METHOCEL Cellulose Ethers

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Technical Handbook

ContentsAn Introduction to METHOCEL Cellulose Ethers . . . . . . . . . . . . . . . . . . . . 1

General Properties of METHOCEL Cellulose Ethers . . . . . . . . . . . . . . . . . 3

Applications for METHOCEL Cellulose Ethers . . . . . . . . . . . . . . . . . . . . . . 7

Regulated Uses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

How to Prepare Aqueous Solutions of METHOCEL Cellulose Ethers. . . . 11

How to Prepare Solutions of METHOCEL Cellulose Ethers

in Nonaqueous Solvents and Nonsolvent Media. . . . . . . . . . . . . . . . . . . 14

Properties of METHOCEL Cellulose Ethers in Powder Form. . . . . . . . . . . 15

Properties of Solutions of METHOCEL Cellulose Ethers . . . . . . . . . . . . . . 16

Thermal Gelation in Aqueous Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Properties of Films of METHOCEL Cellulose Ethers. . . . . . . . . . . . . . . . . . 26

Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Handling Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

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* Trademark of The Dow Chemical Company

METHOCEL* cellulose ethers arewater-soluble polymers derived from cellulose, the most abundantpolymer in nature. For over 50 years these versatile products have played an important role infoods, cosmetics, pharmaceuticals,latex paints, construction products, ceramics, and a host of other applications.

METHOCEL products are used asthickeners, binders, film formers,and water-retention agents. Theyalso function as suspension aids,surfactants, lubricants, protectivecolloids, and emulsifiers. In addition,solutions of METHOCEL thermallygel, a unique property that plays akey role in a surprising variety ofapplications. You won’t find thisvaluable combination of propertiesin any other water-soluble polymer.

Multifunctionality and EfficiencyImprove Formulation Economy

The fact that so many usefulproperties are simultaneouslypresent and often act incombination can be a significanteconomic advantage. In manyapplications, two, three, or moreingredients would be required to do the same job performed by asingle METHOCEL product. Inaddition, METHOCEL celluloseethers are highly efficient, oftenyielding optimum performance at a lower concentration than that required with other water-soluble polymers.

Range of Products Offers Formulating Versatility

The broad range of METHOCELproducts available is certainly onereason they’ve been used successfullyin so many different applications.There are two different chemicaltypes and each is available indifferent grades, physical forms, and viscosities. By choosing a specificMETHOCEL product, it’s possible

to obtain the optimum degree ofthickening, binding, moistureretention, and other propertiesdesired in a given formulation.

Premium and Food Grades forFood and Drug Applications

METHOCEL Premium and Foodproducts have long been used by the food and drug industries. Bothmethylcellulose and hydroxypropylmethylcellulose are recognized asacceptable food additives by theU.S. Food and Drug Administration(FDA) and are listed in the FoodChemicals Codex and theInternational Codex Alimentarius.Both are included in the UnitedStates Pharmacopoeia (USP XXI).Methylcellulose is consideredGenerally Recognized As Safe(GRAS) by the FDA.

Standard Grades for Other Applications

Standard grade METHOCEL products have the same performanceproperties as Premium grades. The major difference is thatStandard grades can have slightlyhigher levels of impurities. Standardgrades are not approved for use infoods, although some Standardgrade products may be used as components of containers coming in contact with food (indirect food additive).

Viscosity Grades from 3 to 100,000 mPa·s

METHOCEL cellulose etherproducts are available in various viscosity grades, ranging from 3 toover 200,000 mPa·s.† Because theviscosity of a solution depends onthe concentration of METHOCEL,this wide range of product viscosityallows you to obtain the viscosityyou want in a formulation, whileusing a concentration that gives the desired level of otherperformance properties.

Available as Powders, Surface-treated Powders, and in Granular Form

For further formulating versatility,METHOCEL products are available in three different forms: powder, surface-treated powder, and granular.The form influences the techniquesused in making solutions. Untreatedpowders are soluble in cold water,but must be thoroughly dispersedbefore they begin to dissolve.Surface-treated powders and granularproducts can be added directly toaqueous systems. The dissolution ofthese products can be controlled bya shift in pH.

Techniques commonly used inpreparing solutions with differentphysical forms of METHOCEL products are summarized on pages 11–14 of this handbook.

Key to Product Nomenclature forMETHOCEL Products

METHOCEL is a trademark of The Dow Chemical Company for aline of cellulose ether products. Aninitial letter identifies the type of cellulose ether. “A” identifiesmethylcellulose products. “E”, “F”,“J”, and “K” identify differenthydroxypropyl methylcelluloseproducts.

The number that follows identifies the viscosity in millipascal-seconds(mPa·s) of that product measured at2% concentration in water at 20°C.In designating viscosity, the letter“C” is frequently used to represent100 and the letter “M” is used torepresent 1,000.

Several different suffixes are alsoused to identify special products. “P” is sometimes used to identifyMETHOCEL Premium grade products. “LV” refers to special“low viscosity” products. “G” identifies “granular” products. The letter “S” identifies

An Introduction to METHOCEL Cellulose Ethers

† Note: mPa.s (millipascal-seconds) is equivalent to centipoise. All solution viscosities are measured with Ubbelohde viscometers at 2% concentration in water at 20˚C (68˚F).

“surface-treated” products, “CR”denotes a controlled-release grade,and “FG” identifies food grade.Developmental grades are denotedby the letter X plus a second letter (usually U or Y) plus a five-digit code.

There are also a number of special-purpose METHOCEL productsdeveloped for cosmetics,pharmaceuticals, ceramics, andother applications which havedifferent systems of nomenclature.For example, METHOCEL 40-Series products make up a familyof special surface-treated products for cosmetic formulations.

Example A: METHOCEL A4CPremium is the designation for aPremium grade methylcelluloseproduct having a viscosity of 400 mPa·s.

Example B: METHOCEL J5MS is a Standard grade hydroxypropylmethylcellulose product with a viscosity of 5,000 mPa·s, whichhas been surface-treated for easy dispersion.

How to Get Started Formulatingwith METHOCEL

To completely evaluate how METHOCEL cellulose ethers canimprove quality, performance, andeconomy in your formulations,you’ll want to try them in yourown lab. Whether you aredeveloping an entirely new productor working to improve an existingone, chances are you’ll find aMETHOCEL product that’s ideally suited to your needs.

Free Samples and Literature Available

Sample quantities of METHOCELproducts are available free ofcharge for your developmentalwork. You can obtain samples bycalling one of the numbers listedon the back cover of this brochure.Literature covering the use ofMETHOCEL products in many ofthe applications listed on pages 7–9of this handbook is also availableon request. Just tell us what typesof formulations or products youare evaluating, and we’ll send you all the current literature thatapplies. Or visit our website atwww.methocel.com for a completeselection of downloadable literature.

Our Technical Service andDevelopment Staff Can Help

Talking with someone on ourTechnical Service and Development(TS&D) staff can save you a greatdeal of formulation time. In certainapplications, a blend of METHOCELproducts may give the best results,and the details may have alreadybeen worked out by someone inour lab. We have technical personnelwho specialize in foods, ceramics,paints, cosmetics, pharmaceuticals,construction products, and otherspecific uses for METHOCELproducts. By taking advantage oftheir experience with METHOCEL,you’ll get a head start with yourformulation and be certain of getting the most out of these versatile products.

Contact Us Today!

Again, if you would like samples,additional literature, or technicalassistance, don’t hesitate to call. Our numbers are listed on theback cover of this brochure. Calltoday. The sooner you get startedformulating with METHOCEL,the sooner you’ll start seeingimproved performance and economy in your products. Our website also contains valuable information to assist you in learning more aboutMETHOCEL.

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General Properties of METHOCEL Cellulose EthersGeneral properties common to thewhole family of METHOCEL cellulose ether products are listedbelow. Individual METHOCELproducts exhibit these properties to varying degrees and may haveadditional properties that aredesirable for specific applications.Detailed information on theperformance properties ofMETHOCEL products can befound on pages 15–21.

Water solubility. METHOCEL cellulose ethers dissolve in waterwith no sharp solubility limit.Surface-treated and granularMETHOCEL products can beadded directly to aqueous systems.This feature provides exceptionalhandling flexibility and control ofsolubilization rate. Althoughuntreated METHOCEL powders aresoluble in cold water, they must firstbe thoroughly dispersed in the waterto prevent lumping. Dispersion techniques are described on pages11–13. The maximum concentrationis limited only by solution viscosity.

Organic solubility. Certain types andgrades of METHOCEL celluloseethers are also soluble in binaryorganic and organic solvent/watersystems, providing a uniquecombination of organic solubilityand water solubility.

No ionic charge. METHOCEL cellulose ethers are nonionic andwill not complex with metallic saltsor other ionic species to form insoluble precipitates.

Thermal gelation. Aqueous solutionsof METHOCEL products gel when heated above a particular temperature, providing controllablequick-set properties. Unlike gelsformed by protein thickeners, the gels go back into solution upon cooling.

Surface activity. METHOCELproducts act as surfactants inaqueous solutions to provideemulsification, protective colloidaction, and phase stabilization.Surface tensions range from 42 to64 mN/m. The surface tension ofwater is 72 mN/m; a typicalsurfactant has a surface tension of 30 mN/m.

Metabolic inertness. Used as foodand drug additives, METHOCELproducts do not add calories to the diet.

Enzyme resistance. Enzyme-resistant METHOCEL productsprovide excellent viscosity stabilityduring long-term storage.

Low taste and odor. METHOCELcellulose ethers have excellent (low)flavor and aroma properties, which is important in food andpharmaceutical applications.

pH stability. METHOCEL celluloseethers are stable over a pH range of2.0 to 13.0.

Water retention. METHOCEL cellulose ethers are highly efficientwater-retention agents. This is valuable in food products, ceramics,coatings on adsorbent constructionsubstrates, and many other applications.

Thickening. METHOCEL celluloseethers thicken both aqueous andnonaqueous systems. The viscosityis related to the molecular weight,chemical type, and concentration ofthe specific METHOCEL product.

Film formation. METHOCELproducts form clear, tough, flexiblefilms that are excellent barriers tooils and greases. In foodapplications, this property is often

used to retain moisture and preventoil absorption during cooking.

Binding. METHOCEL celluloseethers are used as high-performancebinders for pigments, paper, tobaccoproducts, structured foods,pharmaceutical products, and ceramics.

Lubrication. METHOCEL productsare used to reduce friction in rubber,cement, and ceramic extrusions.They are also used to improvepumpability of concrete and sprayplasters, such as stucco, and in food applications as lubricity aids in extrusion and other forming processes.

Suspending. METHOCEL productsare used to control settling of solidparticles, for example, herbs andspices in salad dressings, solids in ceramic slips, and antacid suspensions.

Protective colloidal action. METHOCEL products are used toprevent droplets and particles fromcoalescing or agglomerating.

Emulsification. METHOCEL cellulose ethers stabilize emulsionsby reducing surface and interfacial tensions and by thickening the aqueous phase.

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Nonaqueous Solvent Solubility

In general, binary solvent systemsfunction more effectively withMETHOCEL products than single solvents. Where alcohols comprisepart of the binary solvent, solubilityimproves as the molecular weight of the alcohol decreases. Table 1lists several compounds which aretypical of the types of solvents that can be used with certainMETHOCEL cellulose ether products.

Table 1: Typical Nonaqueous Solvents Usedwith METHOCEL Cellulose Ethers

• Furfuryl alcohol• Dimethyl formamide• Dimethyl sulfoxide• Methyl salicylate• Propylene carbonate• Formic acid• Glacial acetic acid• Pyridine• Mixtures of methylene chloride and

ethyl, methyl, or isopropyl alcohols• Mixtures of chloroform and methanol

or ethanol• N-Methyl pyrrolidone

Solvent Solubility at ElevatedTemperatures

METHOCEL E and METHOCEL Jcellulose ether products possessstructures that provide unusual solubility properties. They are soluble in certain nonaqueous mediaat elevated temperatures, permitting the formulation of mixes which canbe fabricated by techniques ofextrusion, hot-melt casting, andinjection and compression molding.Examples of suitable “hot solvents”are found in Table 2.

METHOCEL 310 Series Products

METHOCEL 310 Series products are granular, high-viscosity materials(Table 3) that are sold only inEurope at this time. Controlledgranulometry provides good dry-flow properties, low dust formation,and lump-free dispersibility in water as well as organic solvents.Their carefully balanced level ofsubstitution renders them soluble in both water and certain organic solvents or blends of solvents (Table 4). METHOCEL 310cellulose ether products can beadded directly to any solvent orblend of solvents under normalagitation. When using solvent blendsthere is no need to pre-disperse theproduct in a non-solvent or low-solvent component.

SolventBoiling Point

°CSolubility Point

°CDegree ofSolubilitya

GlycolsEthylene glycol 197.3 158 CDiethylene glycol 244.8 135 CPropylene glycol 188.2 140 C1,3-Propanediol 214 120 CGlycerine 290 260 PDOWANOL* EE ethylene 134.7 120 C

glycol, ethyl etherDOWANOL TPM 242.4 160 P

tripropylene glycol, methyl ether

EstersEthyl glycolate 160 110 CGlyceryl monoacetate (Acetin) 127 100 C

at 4 mbarGlyceryl diacetate (Diacetin) 123–133 100 C

at 5 mbarAmines

Monoethanolamine 170–172 120 CDiethanolamine 268–269 180 C

Table 2: Representative Solvents for METHOCEL E and METHOCEL J Cellulose Ether Productsat Elevated Temperatures

* Trademark of The Dow Chemical Companya C= completely soluble; P= partially soluble

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Physical Form Slightly off-white granules

Table 3: Typical Properties for METHOCEL 310 Cellulose Ether

Solution Appearance

Clear, Hazy,Smooth Structured Swellable Insoluble

Ethanol (EtOH)

Methanol (MeOH)

Ethanol/H2O 40/60

Methanol/H2O 40/60

Methylene chloride (MeCl2)

MeCl2/EtOH 84/16

MeCl2/MeOH 84/16

Tetrahydrofuran (THF)

THF/H2O 90/10-80/20

Isopropanol

Isopropanol/H2O 90/10-60/40

Isopropanol/MeCl2

1,1,1-Trichloroethane

Polypropylene glycol

Polypropylene glycol/H2O 70/30 delayed thickening

Butylglycol

Butylglycol/H2O 50/50

Dioxane

Acetone

CELLOSOLVE™

Dimethylformamide

DOWANOL PM

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Solvents

Solvent Type after 1 hour after 24 hoursin methanol (MeOH) 500 mPa.s 650 mPa.sin ethanol (EtOH) 600 mPa.s 900 mPa.sin methylene chloride (MeCl2) 7,500 mPa.s 10,000 mPa.s

Moisture (as packaged) max. 8%

Sodium chloride max. 1.5%

Particle size ca. 100-500 micron

Nominal viscosity1% Brookfield RVT,RT, 20 rpm

Table 4: Some Typical Solvents and Solvent Blends for METHOCEL 310 Cellulose Ether

Chemistry of METHOCEL Cellulose Ethers

METHOCEL cellulose etherproducts are available in two basictypes: methylcellulose andhydroxypropyl methylcellulose.Both types of METHOCEL have thepolymeric backbone of cellulose, anatural carbohydrate that contains a basic repeating structure ofanhydroglucose units (Figure 1).During the manufacture of celluloseethers, cellulose fibers are heatedwith a caustic solution which in turnis treated with methyl chloride, yielding the methyl ether of cellulose.The fibrous reaction product is purified and ground to a fine, uniform powder.

Methylcellulose is made using only methyl chloride. These areMETHOCEL A brand products.For hydroxypropyl methylcelluloseproducts (METHOCEL E, F, J, andK brand products), propylene oxide is used in addition to methylchloride to obtain hydroxypropylsubstitution on the anhydroglucoseunits. This substituent group,–OCH2CH(OH)CH3–, contains a secondary hydroxyl on thenumber two carbon and may alsobe considered to form a propylene glycol ether of cellulose. These products possess varying ratios of hydroxypropyl and methyl substitution, a factor whichinfluences organic solubility and thethermal gelation temperature ofaqueous solutions.

There are also special-gradeMETHOCEL products availablethat have been formulated to meet the requirements of specificindustries.

Degree of Substitution

The amount of substituent groupson the anhydroglucose units of cellulose can be designated by weightpercent or by the average number of substituent groups attached to the ring, a concept known to cellulose chemists as “degree of substitution” (D.S.).

If all three available positions oneach unit are substituted, the D.S. isdesignated as 3; if an average of twoon each ring are reacted, the D.S. isdesignated as 2, etc.

The number of substituent groupson the ring determines theproperties of the various products.METHOCEL A cellulose ethercontains 27.5 to 31.5% methoxyl,or a methoxyl D.S. of 1.64 to 1.92,a range that yields maximum watersolubility. A lower degree ofsubstitution gives products havinglower water solubility, leading toproducts that are only soluble incaustic solutions.

Higher degrees of substitutionproduce methylcellulose productsthat are soluble only in organic solvents.

In the METHOCEL E, METHOCEL F, and METHOCELK cellulose ether products, themethoxyl substitution is still themajor constituent (Table 5). Themolar substitution (MS) reports thenumber of moles of hydroxypropylgroups per mole of anhydroglucose.In the METHOCEL J and 310-Series products, the hydroxypropylsubstitution is about 50% of thetotal substitution.

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Hydroxypropyl MethylcelluloseMETHOCEL E, METHOCEL F, METHOCEL J, and METHOCEL K brand products

MethylcelluloseMETHOCEL A brand products

ProductMethoxyl Degree

of SubstitutionMethoxyl

%Hydroxypropyl

Molar Substitution Hydroxypropyl

%

METHOCEL A 1.8 30 — —METHOCEL E 1.9 29 0.23 8.5METHOCEL F 1.8 28 0.13 5.0METHOCEL J 1.3 18 0.82 27METHOCEL K 1.4 22 0.21 8.1METHOCEL 2.0 25 0.8 25310 Series

Table 5: Degree of Substitution for METHOCEL Products

Figure 1: Typical Chemical Structures of METHOCEL Products

The diverse products and processeslisted here all have one thing incommon: All benefit significantlyfrom remarkably small concentrationsof METHOCEL cellulose ethers. In most cases, the major benefits are improved physical properties,but in many applications there areimprovements in processing efficiencyand overall economy as well.

For more detailed information onany of these applications, contactone of the numbers listed on theback cover of this brochure or visitour website at www.methocel.com.

Adhesives

Carpet backsizing compounds.METHOCEL products impartexcellent foaming characteristics or “pan froth” to backsizing compounds. This helps keep theadhesive in the glue line instead ofsoaking into the backing materials.Also, due to thermal gelation, adhesives set quickly and dry fasterat elevated temperatures.

Leather processing adhesives.METHOCEL cellulose ethers areused to paste hides to smooth porcelain or glass surfaces in leather drying processes. Because of itswater retention efficiency and thermal gelation, METHOCEL ismuch more effective than starch-based pastes.

Plywood laminating adhesives.METHOCEL products are used in plywood laminating adhesives to control viscosity in glues for plywood manufacture. Thermalgelation and thickening properties of METHOCEL products keep the adhesive from soaking into the wood.

Cigar and cigarette adhesives. Safe and efficient, METHOCELproducts have long been used asbinders for reconstituted tobaccosheets and as adhesives for cigar andcigarette manufacture.

Wallpaper pastes. Used as the primary adhesive in dry mixes,METHOCEL cellulose ether provides the wet tack required tohold a variety of paper types on thewall, yet has excellent slip propertiesso patterns can easily be matched. In premixed pastes, METHOCEL is used to control viscosity andimprove wet tack. Pastes made withMETHOCEL cellulose ethers areeasily cleaned up with water anddon’t provide a source ofnourishment for insects.

Latex adhesives. METHOCEL products are used as thickeners in a variety of latex adhesives, such asadhesives used in shoe manufacturing.Fast drying speeds and high wet-tack strength due to thermal gelation are key benefits in many of these applications.

Agricultural Chemicals

Dispersing agents. METHOCELcellulose ethers are used as suspendingand dispersing aids for wettable pesticide and fertilizer powders.They provide high wet tack andadhesion to waxy plant surfaces.Chemically inert and nonionic,METHOCEL cellulose ether is compatible with a wide range ofactive ingredients.

Spray adherents. Spray adherents or “seed stickers” made withMETHOCEL products effectivelybind pesticides, inoculants, andnutrients to seeds. METHOCELproducts feature low plant toxicityand won’t harm germinating plants.

Ceramics Processing

Tape casting. Use of METHOCELproducts provides better flow and leveling and more uniformthickness. Low sodium residuesprovide the purity necessary forelectronic items. Thermal gelationreduces binder migration andsurface faults.

Extrusion forming. Used as a temporary binder and processingaid, METHOCEL cellulose ethersallow precise control of rheology inceramic mixes, permitting broaderoperating ranges. Lubricity reducesenergy consumption and die wear,and promotes smoother surfaces.Thermal gelation permits extrusionof extremely delicate, thin-walledshapes without sag or deformation.

Dry and isostatic pressing. METHOCEL products provide optimum grain lubrication fortighter, more uniform packing. The results are more predictablegreen densities, less shrinkage duringfiring, and higher fired strengths.

Glazes/porcelain enamel. METHOCEL cellulose ethersimprove control of viscosity andrheology and fire out completely inthe kiln.

Injection molding. Use of METHOCEL cellulose ethers provides higher green densities and better green strength. In high-temperature coatings/refractorymixes and mortars, METHOCELimproves workability andapplication properties. BecauseMETHOCEL products have lowionic salt residues, they won’t lowermelting points. In fact, they canpermit a reduction in use ofplasticizers with low melting points.

Chemical Specialties

Resins. METHOCEL cellulose ethers are used to control rheologyand as a colloidal stabilizer in avariety of epoxy, fiberglass, andurea-formaldehyde resins. METHOCEL provides ideal flowand leveling characteristics, plusquick-set properties due to thermal gelation.

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Applications for METHOCEL Cellulose Ethers

Rubber. METHOCEL products are used as mold-release agents, stabilizers, and thickeners in rubberlatexes. METHOCEL celluloseethers contribute to more uniformdrying and less pinholing.

PVC suspension polymerization.METHOCEL products are used inPVC polymerization as primary andsecondary suspension agents. Theyprovide excellent particle size control,good porosity for improved plasticizerabsorption, low reactor scaling, andhigh bulk densities.

Construction ProductsDrywall tape-joint compounds.METHOCEL products impartworkability, shrink and crack resistance, slip, and adhesion intape-joint compounds. Water retention properties increase opentimes and help maintain a wet edge.

Cement-based tile mortars. METHOCEL cellulose ethers providewater retention and workability to Portland cement-based ceramictile mortars and grouts. They alsoimprove adhesion, reduce skinning,and increase open time.

Masonry mortars. Used asperformance additives in masonrymortars, METHOCEL productsextend board life and improveworkability. METHOCEL alsocontributes to air entrainment, oftenreducing the need for other additivesfor this purpose.

Gypsum adhesives and gypsum andcement hand and spray plasters.METHOCEL cellulose ethers impart workability, pumpability,and consistency to adhesives andhand and spray plasters. They alsoprovide water retention and anti-sag properties.

Wall and ceiling textures. METHOCEL products impartpumpability, adhesion, workability,and water retention in wall and ceiling texturizing products.

Cement plaster and stucco. METHOCEL cellulose ethers provide water retention for propercuring, improved workability, andpumpability.

FoodsBakery products. Thermal gelationaids in gas retention during baking,increasing baked volumes andimproving texture. METHOCEL also provides a more moist texture,increased shelf life, improvedemulsification of batters, and betterfreeze/thaw stability.

Confections. In glazes, icings, andcoatings, METHOCEL food gumsadd lubricity for easier application,provide creamier texture, improvedspreadability, and clean flavorrelease. In addition, METHOCELgums thermally gel during heating,keeping icings and glazes intact, andduring cooling revert to the originalconsistency of the product.

Pie and pastry fillings. Thermal gelation reduces boil-over during baking and inhibits moisture migration from fillings to crusts during freezing. METHOCEL alsoimproves freeze/thaw stability.

Frozen desserts. METHOCEL products modify ice-crystal size togive smoother textures and improveemulsion stability. Increased airentrainment improves overrun.

Whipped toppings. METHOCELproducts improve whipping properties for better body andappearance. Improved emulsion stability prevents syneresis andextends open times. METHOCELinhibits phase separation in frozentoppings, even through repeatedfreeze/thaw cycles.

Structured vegetable products.METHOCEL products offer excellent film formation and highbinding performance for foods thatneed to keep their componentstogether. Products like vegetarianburgers, onion rings, and formedpotato products are all improved by the binding strength and film formation qualities ofMETHOCEL products.

Structured and extruded foods. Lowconcentrations of METHOCEL give optimum binding strength inmatrix systems. Due to moistureretention and oil insolubilityproperties, fried foods are moremoist, less greasy. Thermal gelationgives increased control over textureand “bite.” Increased lubricity aidsin processing.

Frying batters. In addition to forming an oil-insoluble barrier toblock oil absorption and moistureloss during frying, METHOCELproducts improve adhesion of batters to meat and vegetable substrates. As a result, blow-off ofbatters is reduced and the life of frying oil is extended.

Salad dressings and sauces. Betterstability for oil-in-water emulsionsextends the shelf life of productscontaining METHOCEL. Solids stayin suspension longer and body andpouring characteristics are controlled.

Gelled FuelsFuel thickeners. METHOCEL cellulose ethers are used as thickenersfor gelled alcohol used in charcoallighters, restaurant candles, andcanned-fuel products.

Household ProductsCleaners and detergents. Use of METHOCEL provides viscositycontrol, cling, foaming, soil anti-redeposition, and emulsion stabilization to household cleaners and detergents.

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PaintsLatex paints. METHOCEL cellulose ethers are used asthickeners, protective colloids, and pigment-suspension aids in latexpaints. They provide high enzymeresistance which helps stabilize viscosity. Film-forming propertiescontribute to better paint film quality with fewer pinholes. Theproduct uniformity offered byMETHOCEL cellulose ethers canmean lower quality control costsand more predictable performancefor paints. Their use also improveswet-edge retention. They offer flexibility and ease of incorporation.

Paint RemoversScrape-off and flush-off paintremovers. The unique combinationof organic and water solubilityoffered by METHOCEL productsmakes them ideal thickeners forscrape-off and flush-off paintremovers (both methylene chlorideand alternative paint strippers).They provide the thickening andcling needed to retain the paintremover on vertical or inclinedsurfaces, yet permit the softenedpaint to be rinsed off easily with water.

Paper ProductsGrease-proof coatings, adhesives,release coatings, and surface sizings. Grease and oil barrier properties, in conjunction with film-forming capabilities, makeMETHOCEL valuable in a varietyof paper coatings and sizings. Theexcellent film properties (high tensilestrength and good elongation)offered by METHOCEL play keyroles in these applications.

Personal Care ProductsShampoos. METHOCEL celluloseether is widely used as a thickener in shampoos. Because the thickeningperformance of METHOCEL doesn’t depend on a high surfactant

level, it’s the thickener of choice for shampoos designed for dry andnormal hair. METHOCEL alsohelps stabilize foams, so shampooshave better lather characteristics.

Body Gels. The natural lubricity ofMETHOCEL products can improveproduct flow, aid in dispensing andenhance sensory characteristics. Justas in shampoos, METHOCEL cellulose ethers add texture andprovide a superior volume oflubricious, stable lather especiallyimportant in the formation ofbubble baths and shower gels.

Creams and lotions. METHOCELcan contribute film-forming andsecondary-thickening propertieswhich improve after-feel and othersensory characteristics in creams and lotions.

PharmaceuticalsTablet coatings. METHOCEL cellulose ethers form strong filmswith good adhesion. They providetaste-masking films and act as excellent barriers for water-sensitivedrugs or components. Coatings of METHOCEL also increasecompressive strength and reduce friability.

Granulation. Used at low concentrations as binders in thegranulation process, METHOCELproducts produce hard tablets with low friability, yet don’tnegatively affect tablet disintegration.METHOCEL allows the reductionof compression force, an importantfactor in extending the life oftooling and equipment.

Controlled release. METHOCEL cellulose ether can be used for controlled-release pharmaceuticalsusing two different methods. It isused in hydrophilic-matrix tablets orcapsules as described in a separatebulletin on sustained release. Inaddition, METHOCEL is used indiffusion control films comprised ofMETHOCEL cellulose ethers and

ETHOCEL* ethylcellulose resins.The water-soluble METHOCEL dissolves out of the film, leaving the water-insoluble ETHOCELethylcellulose. Drug diffusion andfilm porosity are controlled by theamount of METHOCEL used.

Water-soluble thermoplastics.METHOCEL cellulose ethers can be heated and mixed with aplasticizer for extrusion or moldinginto a wide range of physical forms.This process is used to producesingle-unit matrix tablets; multi-particle delivery, such as extrudedbeads or chips; transdermal patches;suppositories; or liquid-filled hard-shell capsules.

Liquid preparations. METHOCELproducts are used in oral and topical liquid pharmaceuticalsbecause they are excellent thickeners,improve emulsion stability, suspendsolids, lubricate, and retain moisture.The protective colloid action and emulsifying properties ofMETHOCEL also benefit many liquid formulations.

PrintingPrinting inks. METHOCEL cellulose ethers are used asthickeners and suspending agentsfor water-based inks.

TextilesTextile printing pastes. Used as emulsion stabilizers in textile printing pastes, METHOCEL cellulose ethers help keep inks fromwicking into fabrics.

Fabric sizings. METHOCEL helps hold fibers together, whichstrengthens fabrics duringmanufacturing processes. Thelubricity of METHOCEL helps cutfriction, permitting faster equipment speeds.

Temporary adhesives. Excellent wet-tack and quick-set propertiesmake METHOCEL an ideal temporary fabric adhesive.

9* Trademark of The Dow Chemical Company

Chemical Inventory

METHOCEL products,methylcellulose and hydroxypropylmethylcellulose, comply with allapplicable rules and orders underToxic Substances Control Act PL94-469. The Chemical AbstractsServices Registry No. (CAS) is 9004-67-5 for methylcellulose and9904-65-3 for hydroxypropylmethylcellulose.

METHOCEL products have also been reported for the following inventories:

European Inventory of ExistingChemical Substances (EINECS)

Australia Inventory of ChemicalSubstances (AICS)

Ministry of International Trade andIndustry Inventory (MITI, theJapanese inventory)

Canadian Domestics Substances List (DSL)

Many countries are in the midst ofcreating new chemical inventories.

Pharmaceuticals

Premium grades of METHOCEL A,METHOCEL E, METHOCEL F,and METHOCEL K products areused for pharmaceutical and topicalapplications. Premium grades ofMETHOCEL products meet thespecifications of the United StatesPharmacopoeia (USP XXIII),European Pharmacopoeia (EP) andJapanese Pharmacopoeia (JP) andare listed as methylcellulose andhypromellose1. In addition,methylcellulose (METHOCEL Aproducts) is Generally RecognizedAs Safe (GRAS) by the U.S. Foodand Drug Administration.

To support new drug applications inthe United States, masters files forthese products are on file at theBureau of Drugs of the U.S. Foodand Drug Administration.

Foods

METHOCEL food gums have long been used in the food industry.METHOCEL food gums areapproved within the FoodChemicals Codex and are listed asmethylcellulose and hydroxypropylmethylcellulose.

In the U.S., methylcellulose isapproved as a multiple purposeGRAS food substance according to21CFR 182.1480. It is also allowedfor use in meat products according to 9CFR 318.7 and 9CFR 381.147.Hydroxypropyl methylcellulose isapproved for direct food use by theFDA under 21CFR 172.874. It isalso approved by the USDA as anemulsifying agent, binder, thickener,and stabilizer and is listed in theStandards and Labeling Policy Bookpublished by the USDA. Becausethey are approved for direct fooduse, METHOCEL products can alsobe used as packaging componentsand in indirect food applications.

In the European Union,METHOCEL food gums areapproved for use within theEuropean Directive 95/2/EC.Hydroxypropyl methylcellulose andmethylcellulose are included inAnnex I of this Directive.

When labeling these foodingredients, one can use either theirproper chemical names or theircommon names. Therefore, onecould use “methylcellulose” or“modified vegetable gum” forMETHOCEL A products. For

METHOCEL E, F, or K products,one could use “hydroxypropylmethylcellulose” or “carbohydrategum.” METHOCEL products arealso certified as kosher for year-round and Passover use by theUnion of Orthodox JewishCongregations of America.

Pesticide UseUnder 40CFR 180.1001, certaininert ingredients used in pesticideformulations are exempt from therequirements of a tolerance.Methylcellulose and hydroxypropylmethylcellulose may be used in formulations applied to growingcrops or raw agricultural commodities after harvest. BothStandard and Premium gradeMETHOCEL cellulose etherproducts are appropriate.

10

Regulated Uses

1 The former official monograph name of hypromellose was “hydroxypropyl methylcellulose” or “HPMC.”

METHOCEL cellulose ether products are carbohydrate polymers which dissolve in coldwater (and in some instances incertain organic solvents) byswelling and subsequent hydration.There is no sharp solubility limitsuch as occurs in the dissolution ofionizing salts. The concentration ofMETHOCEL in solution is usually limited by the viscosity that a manufacturer is equipped to handle.It also depends on the viscosityand chemical type of METHOCELproduct used. Solutions of low-viscosity products can be made at10% to 15% concentration. High-viscosity products find a normallimit at 2% to 3% concentration.

The form of METHOCEL cellulose ether product chosen(powder or surface-treated powder,or granules) influences the techniquesused to make solutions. Surface-treated and granular products canbe added directly to aqueous systems. They disperse readily withmild agitation and dissolve (buildviscosity) gradually under neutralconditions. The dissolution rate of surface-treated products can be increased by adjusting to an alkaline pH after dispersing the powder in water. Althoughuntreated METHOCEL powdersare soluble in cold water, theymust first be thoroughly dispersedin the water to prevent lumping.

Working with Surface-treated Dispersible Powders

In many applications, the combination of easy dispersion incold water and rapid hydration(viscosity build) is desirable.Surface-treated METHOCEL powders are chemically treated sothat they become temporarilyinsoluble in cold water. This allows

the METHOCEL product to beadded to a formulation and dispersed at relatively low shearwithout any significant viscosityincrease initially.

The “time delay” of the hydrationor viscosity build is a function ofthe level of surface treatment aswell as temperature, pH of the system, and concentration of theMETHOCEL product. Normally,the concentration of METHOCELin the system does not become afactor until the concentrationexceeds 5% by weight (relative to water in the system). At higherconcentrations, the time ofhydration (referred to as delaytime) is reduced. The delay time isgenerally reduced as temperature is raised. Figure 2 shows a typicaldelay time as a function of pH,evaluated at room temperature.

In many cases it is desirable to“trigger” viscosity build immediatelyfollowing dispersion. Aqueousslurries can be held for 45 minutesand still remain usable in neutral

systems. A trigger can convenientlybe used by adding a small amountof a base, such as ammoniumhydroxide, sodium bicarbonate,etc. If METHOCEL is dispersed inneutral water (pH approximately 7),there is adequate time for thoroughdispersion. Addition of base toraise the pH to approximately 9causes the hydration to becompleted in just a few minutes.

For best results and to achievemaximum hydration, surface-treatedpowders should be added withgood agitation to a neutral pH system. The system should be agitated thoroughly for a few minutes, followed by an adjustmentof pH to 8.5 to 9.0 with continuedagitation, until full viscosity isreached (usually 10 to 30 minutes).Once the pH has been shifted tothe alkaline side (pH 8.5 to 9.0),allowing full and rapidsolubilization of the surface-treatedproduct, solutions are stable overthe pH range of 3 to 11.

11

How To Prepare Aqueous Solutions of METHOCEL Cellulose Ethers

Figure 2: Typical Hydration Delay Time of Surface-treated METHOCELProducts as a Function of pH

0 2 4 6 8 10pH

1000.0

100.0

10.0

1.0

0.1

Hydr

atio

n Ti

me,

min

The addition of a slurry to an alkaline pigment grind or filler dispersion, or the addition of a slurry to a basic pigment-latex formulation, provides rapidsolubilization and uniform viscosity development. The addition of dry,alkaline pigments or fillers to a slurry on high-speed or low-speedmixing equipment also results inrapid solubilization and viscositydevelopment.

CAUTION: Attempts to adjust the pH of high-concentration slurries may lead toexcessively high viscosity so that they cannotbe pumped or poured. The pH adjustmentshould be made only after a slurry is diluted tothe concentration at which it will be used.

Dispersion Technique

1. Add the surface-treated METHOCELpowder to the water.Begin agitation.

2. Continue agitationand add sufficientammonium hydroxide,sodium bicarbonate,or other alkaline material (e.g., pigmentgrind) to the dispersionto obtain a pH of 8.5 to 9.0. This will result in rapid viscosity development. Continue agitationuntil sufficient hydration has been achieved.

Working with Untreated Powders

Although METHOCEL powders are soluble in cold water, they mustfirst be thoroughly dispersed in thewater to prevent lumping. In someapplications, dispersion can beaccomplished at ambienttemperatures or in cold water byusing an eductor funnel or high-shear mixer. However, if untreatedpowders are added directly to coldwater without sufficient agitation, alumpy solution may result. Lumpingresults from incomplete wetting ofthe individual powder particles.Only part of the powder dissolves, a gelatinous membrane whichshields the remaining powder fromcomplete hydration. Severaldispersion techniques are commonlyused and are described below. Eachhas advantages in certainapplications.

Dispersion in Hot Water

Often called the “hot/cold” technique,this method takes advantage of theinsolubility of METHOCEL celluloseethers in hot water. The powder isfirst dispersed by mixing thoroughlywith 1/5 to 1/3 of the total requiredvolume of water that has been heated to above 90°C (194°F).Mixing continues until all particlesare thoroughly wetted.

For complete solubilization, theremainder of the water is thenadded as cold water or ice to lowerthe temperature of the dispersion.Once the dispersion reaches the temperature at which that particularMETHOCEL product becomeswater soluble, the powder begins tohydrate and viscosity increases.

12

Figure 3: Viscosity Development of METHOCEL A andMETHOCEL K Products Slurried at 2% in Hot Water

100 80 60 40 20 0Temperature, °C

10,000

1,000

100

10

Visc

osity

, mPa

. s

Viscosity on InitialCooling ofMETHOCEL A Premium

Viscosity on InitialCooling ofMETHOCEL K Premium

In some applications, it may be desirable to heat the entire volume of water, disperse the METHOCELpowder, then cool the mixture whileagitating until hydration is complete.It is very important, however, tohave adequate cooling after wettingwith hot water to ensure completehydration and viscosity development.

For improved clarity and reproduciblecontrol of viscosity, solutions ofMETHOCEL A cellulose ether products (methylcellulose) should becooled to 0° to 5°C (32° to 41°F)for 20 to 40 minutes. In general, solutions of METHOCEL E,METHOCEL F, METHOCEL J,and METHOCEL K brand cellulose ethers (hydroxypropylmethylcellulose) require cooling to20° to 25°C (68° to 77°F) or below.

Because complete hydration dependson adequate cooling, METHOCELE, F, J, and K brand products arefrequently used in applicationswhere cold water is not available.Figure 3 illustrates the effects ofcooling hot slurries of METHOCELA and METHOCEL K products.This figure shows that a slurry ofMETHOCEL K brand celluloseether requires much less cooling for hydration than a slurry ofMETHOCEL A cellulose ether.Slurries of METHOCEL E, F, and Jbrand products also require less cooling than METHOCEL A brand products.

Dispersion Technique

1. Heat approximately1/3 the requiredvolume of water to atleast 194°F (90°C).

2. Add the METHOCELpowder to the heatedwater with agitation.

3. Agitate the mixtureuntil the particles arethoroughly wettedand evenly dispersed.

4. For complete solubilization, add the remainder of thewater as cold water or ice to lower the

temperature of the dispersion. Once the dispersion reaches the temperature at which that particularMETHOCEL product becomeswater soluble, the powder begins tohydrate and viscosity increases. See pages 12 and 13 for coolingtimes and temperatures for specificMETHOCEL products.

5. Continue agitationfor at least 30 minutesafter the propertemperature isreached. Yoursolution ofMETHOCEL cellulose ether is now ready to use.

Dispersion by Dry-Blending

Dry-blending involves mixingMETHOCEL powder with otherdry ingredients before adding thewater component. Dry-blending separates the particles of METHOCELcellulose ethers to allow thoroughwet-out and complete hydrationwhen water is added. The minimumratio of other dry, powdered ingredients to METHOCEL powdervaries from 7:1 to 3:1.

Dispersion Technique

1. Combine METHOCEL powderwith other dry-powderingredients. The suggested ratio of otherdry-powder ingredients

to METHOCEL is 7:1; however, theratio may vary from 7:1 to 3:1.

2. Thoroughly blend the dry components.

3. Add the dry mix to the water with agitation. The rate ofhydration will dependupon both the relative

particle sizes and the rate ofagitation during and after additionof the mixture to the water.

4. Agitate until theMETHOCEL powderhas completely hydrated and the solution is consistentlysmooth. Your solutionof METHOCEL cellulose ether is now ready for further processing.

Dispersion in Concentrated SaltSolutions

Both untreated and surface-treatedMETHOCEL cellulose ethers can be dispersed in concentrated saltsolutions. Dissolution occurs whenthe brine is diluted with cold water.

13

Solubility in Nonaqueous Solvents

The solubility of METHOCEL cellulose ethers in nonaqueous mediavaries according to the nature andquantity of substituent groups on theanhydroglucose chain. When using awater-miscible, organic solvent, suchas an alcohol or glycol, use a ratio of at least 5 to 8 parts of solvent to 1 part METHOCEL.

Dispersion in Non-solvent Media

Untreated METHOCEL celluloseethers may also be dispersed in non-solvent media such as vegetableoil, propylene glycol, polyethyleneglycol, glycerine, corn syrup, andhigh-fructose corn syrup. A ratio of 5 to 8 parts non-solvent to 1 partMETHOCEL is recommended toobtain a fluid slurry. The dispersionof METHOCEL in a non-solvent medium may then be added to coldwater, or the cold water may beadded to the dispersion.

Dispersion Technique

1. Add the METHOCELcellulose ether to the non-solvent. A ratio of5–8 parts non-solvent to 1 part METHOCEL isrecommended to obtain a liquid slurry.

2. Agitate the mixtureand METHOCEL powder until the particlesof METHOCEL celluloseether are evenly dispersed.

3. The dispersion ofMETHOCEL in a non-solvent medium may beadded to cold water, orthe cold water may beadded to the dispersion.

4. Continue mixing untilthe METHOCEL powderis completely hydratedand the solution issmooth. You can now addthe remaining ingredientsin your formulation.

14

How To Prepare Solutions of METHOCEL CelluloseEthers in Nonaqueous Solvents and Nonsolvent Media

METHOCEL cellulose ether products are white to slightly off-white powders which are essentiallyodorless and tasteless. The apparentdensity of the powders ranges from0.25 to 0.70 g/cm3 (250–700 kg/m3).

Moisture Sorption

METHOCEL products sealed intheir original shipping containersabsorb little to no atmosphericmoisture. Once a container isopened, however, there is pickup of moisture from the air. When“exposed” METHOCEL celluloseether is weighed, a portion of thetotal weight, therefore, may bewater. Such weight must be correctedfor moisture content to ensure thatthe proper weight of METHOCELis used to give the desired viscosity.

To minimize moisture pickup,opened bags should be tightlyresealed. The moisture-sorption rate of METHOCEL K brand products is somewhat greater thanfor METHOCEL A brand products.However, the moisture-sorptionrates are about the same within asingle chemical type. Typical moisture sorption is shown in Figure 4.

Resistance to Microorganisms

An important property of METHOCEL cellulose etherproducts is their high resistance to attack by microorganisms.METHOCEL products with higherdegrees of substitution are especiallyresistant to enzymes. The fact thatvirtually all METHOCELmethylcellulose and METHOCELhydroxypropyl methylcelluloseethers pass through the intestinaltract essentially unchanged attests tothe stability of these products to awide range of biochemical andenzymatic systems. Shelf-life inpaints and other latex-basedcoatings, and stability of solutions and other products containing METHOCEL celluloseether, can be greatly increased bythis resistance to microorganisms.

As the cellulose is modified by substitution with various radicals,such as alkyl and hydroxyalkylgroups, resistance to microbial attack increases. Several researchershave reported that the degree ofsubstitution (D.S.) of water-solublecellulose derivatives was a primaryfactor, with a threshold D.S. valueof 1.0 required for protection.†

Because METHOCEL celluloseether products have excellent uniformity of substitution, with aD.S. much higher than 1.0, theypossess excellent resistance to microbial attack.

15

Properties of METHOCEL Cellulose Ethers in Powder Form

Figure 4: Equilibrium Moisture Contentvs. Percent Relative Humidity, 25°C

0 10 20 30 40 50 60 70 80 90 100% Relative Humidity, Mean Average Value,

+95% Probability

80

70

60

50

40

30

20

10

0

%H 2O,

25°

C

†H.S. Levinson and E.T. Reese, J. Gen. Physiol. 33, No. 601 (1950).E.T. Reese, R.G.H. Siu, and H.G. Levinson, J. Bacteriology 59, No. 485 (1950).E.T. Reese, Ind. Eng. Chem. 49, No. 104 (1957).

Some of the general solutionproperties of METHOCEL celluloseether products are listed in Table 6.

Rheology of Solutions of METHOCEL Cellulose Ether

The rheology of solutions of METHOCEL plays an importantrole in many practical applicationswhere the modification of flowbehavior is essential (for example,paints, cosmetics, food products,building products). A Newtonianfluid is one whose viscosity is independent of shear rate (or velocity gradient of flow). In actualpractice many systems exhibit non-Newtonian flow behavior whereapparent viscosity may decrease(pseudoplastic) or increase (dilatant)with increasing rate of shear.

Rheology of an aqueous solution of METHOCEL is affected by itsmolecular weight, concentration,temperature, and by the presence ofother solutes. In general, aqueoussolutions of METHOCEL exhibitpseudoplastic flow behavior.Pseudoplasticity increases withincreasing molecular weight or concentration. However, at very low shear rates, all solutions ofMETHOCEL cellulose ether appearto be Newtonian and the shear ratebelow which the solution becomesNewtonian increases with decreasingmolecular weight or concentration.Figures 5 and 6 illustrate this behavior (the numbers on curvesindicate viscosity types).

16

Properties of Solutions of METHOCEL Cellulose Ethers

Table 6: General Solution Properties

Specific gravity, 4°C, all types1% solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00125% solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.011710% solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0245

Refractive index, 2% solutions, all types1.336

Partial specific volume4,000 mPa·s METHOCEL A . . . . . . . . . . . . . . . . . . . . . . . 0.725 cm3/g (0.087 gal/lb)4,000 mPa·s METHOCEL E . . . . . . . . . . . . . . . . . . . . . . . 0.767 cm3/g (0.092 gal/lb)4,000 mPa·s METHOCEL F . . . . . . . . . . . . . . . . . . . . . . . 0.734 cm3/g (0.087 gal/lb)5,000 mPa·s METHOCEL J . . . . . . . . . . . . . . . . . . . . . . . 0.725 cm3/g (0.087 gal/lb)4,000 mPa·s METHOCEL K . . . . . . . . . . . . . . . . . . . . . . . 0.717 cm3/g (0.086 gal/lb)15,000 mPa·s METHOCEL K . . . . . . . . . . . . . . . . . . . . . . 0.724 cm3/g (0.087 gal/lb)

Freezing point, 2% solutions, all types0.0°C at 2% concentration

Surface tension, 25°C, 0.05% concentrationWater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72–74 x 10-3 Newton/meter (72–74 dynes/cm)Methylcellulose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53–59 x 10-3 Newton/meter (53–59 dynes/cm)Hydroxypropyl methylcellulose . . . . . . . . . . . . . . . . . . . 43–55 x 10-3 Newton/meter (43–55 dynes/cm)

17

Figure 5: Apparent Viscosity vs. Shear Rate, 2% Aqueous Solutions, 20°C

0.1 1 10 100 1,000Shear Rate, s-1

10,000

1,000

100

10

Appa

rent

Vis

cosi

ty, m

Pa. s

4,000

1,500

400

100

25

Figure 6: Apparent Viscosity vs. Shear Rate, for Aqueous Solutions of 4,000mPa.s METHOCEL Cellulose Ethers at Various Concentrations

0.1 1 10 100 1,000Shear Rate, s-1

10,000

1,000

100

10

Appa

rent

Vis

cosi

ty, m

Pa. s

@ 2

0°C

2%

1.5%

1%

0.5%

Molecular Weight/Viscosity Relationships

The apparent viscosity of an aqueous solution of a METHOCEL cellulose ether is proportional to themolecular weight or chain length ofthe specific METHOCEL productused. Commercial designations ofMETHOCEL products are based on viscosity values determined inwater at 20°C, with a concentrationof 2% METHOCEL. Themeasurement methods used aredescribed in the current ASTMmonographs D1347 and D2363.The correlation between the numberaverage molecular weight (Mn) andthe commercial viscosity designation for METHOCEL A cellulose ethersis shown in Figure 7.

Table 7 provides further informationregarding the correlation of number average molecular weight with thecommercial viscosity designation.Intrinsic viscosity is the limiting quotient of the specific viscositydivided by the concentration asinfinite dilution is approached (as the concentration approaches zero).The number average molecularweight (Mn) is calculated from the limiting osmotic pressure of thesolvent as the concentration ofthe solute approaches zero. Theaverage molecular weight (Mw) will be 3 to 10 times the Mn.

Effect of Concentration on Viscosity

Most formulations require a predetermined product viscosity ofMETHOCEL cellulose ether. Figure8 shows how the concentration ofMETHOCEL products of varying viscosity affects the aqueous solutionviscosity at 20°C. The measurementswere made using an Ubbelohde viscometer (ASTM D2363). Datafor both low and high molecularweight METHOCEL products areshown and represent the averagematerial found within a viscosityspecification.

18

Molecular Weight

Figure 7: Molecular Weight/Viscosity Correlation, 20°C

1,000 10,000 100,000

100,000

10,000

1,000

100

10

0

Vis

cosi

ty o

f an

Aque

ous

Solu

tion,

mPa

. s @

20°

C

Mw

Mn

Table 7: Viscosity of Methylcellulose of Various Molecular Weights

5 1.2 53 10,00010 1.4 70 13,00040 2.0 110 20,000

100 2.6 140 26,000400 3.9 220 41,000

1,500 5.7 340 63,0004,000 7.5 460 86,0008,000 9.3 580 110,000

15,000 11.0 650 120,00019,000 12.0 750 140,00040,000 15.0 950 180,00075,000 18.4 1,160 220,000

Intrinsic Number Average Number AverageViscosity Grade Viscosity Degree of Molecular2%, 20°C, mPa·s (h), dL/g Polymerization Weight (Mn)

This graph is plotted on an 8throot scale, not a logarithmic scale.The 8th root of the viscosity is a roughly linear function of the concentration.

The equation which expresses the illustrated approximaterelationship between solutionviscosity and polymerconcentration is �1/8 = (C·�) + 1,where � is the solution viscosity in millipascal-seconds, C is thepolymer concentration in solution(expressed in percent), and � is aconstant specific to the molecularweight. The value of � may becalculated by substitution and maythen be used to calculate theapproximate viscosity at thedesired concentration.

For example, for a 4,000 mPa·s product, (4,000)1/8 = (C·�) + 1. Solving for � yields a value of0.910. For a 1,500 mPa·s product,(1,500)1/8 = (C·�) + 1. Solving for� yields a value of 0.747. Havingcalculated � for a particularMETHOCEL product, this valuecan be used to calculate viscosityat other concentrations.

To find the line for any intermediategrade, locate the desired 2% viscosity above 2% on the abscissaand draw a straight line to thepoint of origin.

Blending for Intermediate Viscosity

METHOCEL products of the samesubstitution type, but of differentviscosity grades, can be blended toobtain an intermediate viscositygrade. Figure 9 is a blending chartthat can be used for this purpose.

To use the chart, mark theviscosity of one material along theleft axis (Scale A) and the viscosityof the other material along theright axis (Scale B). Connect thetwo points in a straight line thatcrosses the graph. In the exampleshown, the viscosities of the

starting materials are 400 mPa·son the left and 15,000 mPa·s onthe right.

Now find the desired finalviscosity on either axis and draw ahorizontal line that intersects withthe first line. From this intersectionpoint, draw a vertical line down tothe bottom scale. The number ofthat scale shows the percentage ofScale B Material needed in theblend. In this example 4,000 mPa·sis the desired final viscosity. So therequired blend is 60% of the15,000 mPa·s (Scale B) materialand 40% of the 400 mPa·s (Scale A) material.

19

Figure 8: Viscosity/Concentration Relationships

0 1 2 3 4 5 6 7

% METHOCEL Cellulose Ether

100,000

75,000

50,000

Vis

cosi

ty, m

Pa. s

@ 2

0°C

15,000

10,000

4,000

1,500

1,000

400250

100

50251510

1

15

5

50

100

400

4,000

15,000

40,000

100,000

1,500

The relationship may be expressedmathematically as: �B

1/8 = x1�11/8 +

x2�21/8 , where x1 and x2 are the

weight fractions of componentsone and two, respectively.

The example on the chart showsthat 60% of 15,000 mPa·s materialand 40% of the 400 mPa·s materialare needed to make a blend havinga viscosity of 4,000 mPa·s.

Effect of pH on Viscosity

Because METHOCEL productsare nonionic, the viscosities oftheir solutions are generally stableover a wider pH range than arethe viscosities of gums that areionic in nature. Outside the rangeof pH 3 to 11, however, there maybe a gradual loss of viscosity athigher temperatures or after longperiods of standing, especially withhigh-viscosity solutions. Solutionsof METHOCEL cellulose ethers inacids or in strong caustic solutionswill decrease in viscosity. This factor should be considered when determining the shelf life of products.

Effect of Additives on Viscosity

In the preparation of formulations,viscosities may occasionally resultwhich are considerably higher thanexpected. This phenomenon can be caused by the interaction ofMETHOCEL with one or more of the formula ingredients. As aresult, it may be possible to useless thickener and still have adequate viscosity.

This effect usually passes througha maximum that is dependent onthe concentration of the interactingmaterials and on the presence ofother ingredients such as pigments,latex particles, or preservatives.

In systems having lower concentrations of additives (~1%),METHOCEL A or METHOCEL Fproducts are frequently suitable. Insystems where the concentration ofadditives is rather high (~10%),the more highly substitutedproducts such as METHOCEL E,J, or K products may be more compatible.

Effect of Freezing on Solutions

Solutions of METHOCEL celluloseether products do not undergoseparation into phases uponfreezing. There is no separation of fluid layers (syneresis) orformation of insoluble

precipitates or haze. This lack ofphase separation on freezing isparticularly important in frozenfood items. As solutions ofMETHOCEL cellulose etherproducts are cooled, solubilizationincreases, as evidenced byincreasing viscosity and improvedclarity of solutions. When thesolutions freeze, part of the wateris held in the latent super-cooledstate and does not freeze. The heatnormally released on freezing (heatof fusion) is decreased by theamount of the super cooling.

20

Figure 9: Blending Chart

0 20 40 60 80 100

% of Scale B Material in Blend

100,000

Sca

le A

V

isco

sity

, mPa

. s @

20°

C

10,000

1,000

100

10

400

100,000

10,000

1,000

100

10

Sca

le B

V

isco

sity

, mPa

. s @

20°

C4,000

15,000

Defoamers for Aqueous Solutions

The foaming of solutions of METHOCEL cellulose ethers is easily controlled by using foam stabilizers and defoamers.

Defoamer concentrations should be kept to the minimum requiredbecause these materials are generallylow in water solubility. The choiceof a defoamer depends on the typeof surfactant, latex, and other ingredients in the system. Fordefoaming complex systems, consultation with the supplier ofdefoamers is suggested.

Antifoam agents are extremely efficient surface-active compositionswhich displace other surface-activesubstances at the air/water interface.Their use, therefore, might interferewith the performance of METHOCELproducts in applications where themechanical properties of solution-surface films is critical.

Preservatives for Aqueous Solutions

METHOCEL cellulose ethersnormally do not requirepreservatives. They are not, however, antimicrobial agents. If contamination occurs,microorganism growth will not be inhibited.

To preserve solutions ofMETHOCEL, addition of 0.05% to 0.15% of DOWICIDE* A antimicrobial or DOWICIL* 75preservative is suggested. Moreinformation on these products isavailable upon request. For regulateduses, you should use the appropriatepermitted preservative.

Compatibility of Aqueous Solutions

The methylcellulose molecule isnonionic and is not precipitated asan insoluble salt by multivalentmetal ions. However, METHOCEL cellulose ethers can be salted out of solution when the concentrationof electrolytes or other dissolved materials exceeds certain limits. This is caused by competition of the electrolytes for water andresults in reduced hydration of the cellulose ether.

Because of the difference in theamounts of organic substitution,METHOCEL E, F, J, K, and 310-Series brand hydroxypropylmethylcellulose products generallyexhibit a higher tolerance for salts insolution than METHOCEL A brandmethylcellulose products. There isonly a slight variation in electrolytetolerance among the variousMETHOCEL hydroxypropylmethylcellulose products.

Water-insoluble materials such aspigments, fillers, etc. will notadversely affect METHOCEL cellulose ethers. Actually, solutions ofMETHOCEL often serve as excellentdispersing media for such materials.Other water-soluble substances, suchas starches, glues, and resins, may ormay not be compatible withMETHOCEL. Tests should be runon these materials to determine compatibility. Because METHOCELcellulose ether products are not soluble in concentrated salt solutions,these media can be used as non-solvent dispersing media fornon-surface-treated METHOCEL products. Subsequent dilutionreduces the salt concentration to alevel that allows dissolution of theMETHOCEL product.

21

* Trademark of The Dow Chemical Company

METHOCEL cellulose ethers possess unique solubility propertiesin aqueous media. These productsare insoluble in water that has been heated above a particulartemperature. Below thosetemperatures, the solution andsolubility of the METHOCELcellulose ether products increase asthe temperature is lowered. Aqueoussolutions of METHOCEL celluloseethers will gel when heated totemperatures that are specific foreach type. The gels are completelyreversible and the solutions liquefyupon cooling. This unique bulkthermal-gelation property provesvaluable, compared to that of othernatural and synthetic gums, in awide variety of applications.

Bulk thermal gelation of aqueoussolutions of METHOCEL is thoughtto be primarily caused by thehydrophobic interaction betweenmolecules containing methoxylgroups. In a solution state at lowertemperatures, molecules are hydratedand there is little polymer-to-polymerinteraction other than simple entanglement. Figure 10 shows theviscosity of a typical solution as it isheated to its gel temperature, thencooled to the original temperature.

As the temperature of the solution is increased, the cellulosic polymersgradually lose their water ofhydration, and viscosity decreases.When the gel point is reached,sufficient dehydration of thepolymer occurs to cause a polymer-to-polymer association, and the solution begins to gel.

Gel strength continues to build as the temperature is held above the gel point.

When the solution is cooled, the geleffect begins to reverse and viscositydrops rapidly. Finally, the viscosityof the cooling solution merges with the original heating curve and increases as the temperaturedecreases. Once the solution hascooled, the viscosity is the same as itwas originally. Thus, the thermalgelation process is reversible andcan be repeated if desired.

22

Thermal Gelation in Aqueous Media

0.25 C/min

0 10 20 30 40 50 60 70Temperature, °C

Vis

cosi

ty, m

Pa. s

200

160

120

80

40

0

Gelled

Incipient GelationTemperature

Cont

inue

d He

atin

g

Heating

Cooling

Figure 10: Gelation of 2.0% Aqueous Solutionof METHOCEL A100 Methylcellulose, HeatingRate 0.25°C/min

Controlling Gel Temperature

The specific temperature at whichbulk thermal gelation occurs (theincipient gelation temperature orIGT) and the firmness of the gel aregoverned by the nature and quantityof the substituent groups attached tothe anhydroglucose ring and, thus,vary with each type of celluloseether. The molecular weight of theparticular METHOCEL productselected has little effect on the geltemperature. However, increasingthe concentration of the solutionlowers the gel temperature as shownin Figure 11.

Within the range of viscosityavailable in the “A” type, the low-viscosity products will have gelpoints substantially higher thanthose of the high-viscosity products. The spread between highand low viscosity for the otherMETHOCEL cellulose ether types is relatively narrow.

The Effects of Heating Rate andAgitation on Gelation

Accurate measurement of gelationtemperature requires care because it is a function of the rate of heatingand the rate of shear. Both a highrate of shear and a fast heating rate result in an apparently high gel temperature.

Agitation also affects the strength ofthe gel. Continued rapid agitationduring gelation may break down the gel structure and alter both thetexture and strength of the gel. Formaximum development of gelstrength, heat the solution wellabove the gelation temperatureunder quiescent conditions.

Gel Strength and Texture

The texture and strength of gelsproduced by heating solutions ofMETHOCEL cellulose ethers varieswith the product type, viscositygrade, and concentration of

METHOCEL used. In applicationswhere a strong, elastic gel is desiredat slight elevations in temperature,METHOCEL A products arerecommended. For softer, non-rubbery gels, METHOCEL F or E products should be used. For an even softer gel texture,METHOCEL K or METHOCEL Jproducts are suggested.

In general, the strength of the gelincreases sharply as molecularweight increases and graduallybecomes constant at or above a viscosity of 400 mPa·s. Gel strength also increases withincreasing concentration.

Effect of Concentration on ThermalGelation

As the temperature of a solution ofMETHOCEL cellulose ether israised, hazing of the solution occursimmediately prior to gelation, andthe viscosity may start to rise. Atthis point, if the concentration ishigh enough, the solution willchange to a soft or firm gel. If theconcentration is below 0.5%, a fluidmixture of individual gel particlesand water is formed, rather than afirm gel.

In general, as the concentration of METHOCEL cellulose ether isincreased, the gelation temperaturewill be lowered. An increase of 2% in concentration can cause a 10°Cdrop in the gelation temperature for METHOCEL A cellulose etherproducts. A 2% increase inconcentration of a solution ofMETHOCEL F cellulose etherproduct lowers the gelationtemperature by only 4°C.

Interfacial Gelation

In addition to bulk-phase gelation,METHOCEL cellulose ethers alsoexhibit interfacial or surface gelationphenomena as a result of their surfactant nature. Interfacial gelationplays an important role in many

applications where a protective colloid, emulsification, or surfactantfunction is desirable. Examplesinclude: suspension polymerizationof vinyl chloride; aqueous foam stabilization in shampoos, bubblebaths; and the stabilization of non-dairy whipped toppings andsalad dressings.

To achieve bulk thermal gelation,concentrations of 1.5 wt % are generally necessary. However, evenat concentrations as low as 0.001wt %, many METHOCEL productsexhibit surface thermal gelation due to the migration of polymermolecules to the air/water interface.Maximum gelation properties areachieved with METHOCEL A, E,and F.

The equilibrium concentration ofMETHOCEL products at any giveninterface depends upon the natureof the interface, presence of othersolvents, temperature, and potentialfor formation of associative structures with other surfactants.However, the concentration ofMETHOCEL at an interface can beorders of magnitude greater thanthat presumed to be present in thebulk phase. As a result, surface filmformation (surface gelation) occurs.

23

Figure 11: Gelation Temperature asa Function of Concentration

1 2 3 4 5 6 7 8 9 10 11 12Concentration, Wt. %

60

55

50

45

40

35

30

25

Gela

tion

Tem

pera

ture

,°C

METHOCEL ESlope = -1.0

METHOCEL FSlope = -1.77

METHOCEL ASlope = -2.33

As a specific example, a 0.01 wt %solution of METHOCEL A15 LVcellulose ether exhibits surface gelation at 20°C, whereas bulk gelation with the same productwould require a concentrationexceeding 12 wt % at such a lowtemperature. A 0.01 wt % solutionof METHOCEL A15 LV cannot bemade to undergo bulk gelation atany temperature.

Surface gelation (filming) occurs very rapidly in many solutions ofMETHOCEL products whetherdilute or concentrated. This effect is most evident (and troublesome)when one employs du Nouy tensiometry to determine surface tension.

Generally speaking, increasing themolecular weight, concentration, or temperature of a solution ofMETHOCEL will promote the onset of surface gelation just as in bulk thermal gelation.

Effect of Additives on ThermalGelation

Additives may either increase or decrease thermal-gelation temperature, depending on whetherthe additive exhibits a coagulant or a solubilizing effect on theMETHOCEL product. For example,solutes such as ethanol, PEG 400,and propylene glycol all raise the gelpoints of METHOCEL products.

This is due to the solubilizing effectwhich they impart. Additives suchas glycerin, sorbitol, and salts lowergel points by lowering the solvency ofthe aqueous system, resulting in amore rapid dehydration of theMETHOCEL product (Table 8).

If a manufacturer requires a highthermal gelation temperature andplans to use additives known toreduce the gel temperature, aMETHOCEL product with a gelpoint higher than the temperaturerequired should be used. As the concentration of the gel-causingadditive increases, the thermal geltemperature decreases. Although thebehavior of a particular solute mustbe determined empirically, the following general guidelines apply.

24

% METHOCEL METHOCEL METHOCEL METHOCELAdditive Additive A15C, °C F4M, °C K4M, °C J5M, °C

None 0 50 63 85 62NaCl 5 33 41 59 42MgCl2 5 42 52 67 50FeCl3 3 42 53 76 53Na2SO4 5 salted out salted out salted out salted outAl2(SO4)3 2,5 salted out 45 48 41Na2CO3 5 salted out salted out salted out salted outNa3PO4 2 32 42 52 43Sucrosea 5 51 66 84 60Sucrose 20 44 59 61 53Sorbitol 20 30 46 48 —Glycerine 20 34 60 65-70 55Ethanola 20 >75 >75 >75 >78Polyethylene Glycol 400a 20 52 >80 >80 >78Propylene glycola 20 59 >80 >80 >78

aNote: This material raises the gelation temperature.

Table 8: Effect of Additives on Gelation Temperature for 2% Solutions of METHOCEL Cellulose Ether

Additives Which Lower Gel Points

Most electrolytes, as well assucrose, glycerine, etc., lower thegel point because they have agreater affinity for water and dehydrate the cellulosic polymer.Decreases in gel temperature are a function of the ions present inthe additive.

Additives Which Raise Gel Points

The effect of an additive that raisesgel point varies with differentMETHOCEL products. For example, the amount of propyleneglycol required to increase thethermal gel point of a solution ofMETHOCEL A cellulose ether by4˚C will increase the gel point of a solution of METHOCEL F by10˚C and METHOCEL K by 20˚C.

The increase in the thermal gelpoint is directly proportional tothe increase in concentration of the additive. Figures 12 and 13illustrate the relationship betweenconcentrations of ethanol andpropylene glycol and the thermalgel point of representativeMETHOCEL products.

25

Figure 13: Effect of Propylene Glycol on GelTemperature, 2% Solutions

0 5 10 15 20Propylene Glycol, % by Volume

25

20

15

10

5

0

Chan

ge in

The

rmal

Gel

Tem

p.,°C

METHOCEL A4M(4,000 mPa.s)

METHOCEL F4M(4,000 mPa.s)

Figure 12: Effect of Ethanol on GelTemperature, 2% Solutions

0 5 10 15 20Ethanol, % by Volume

25

20

15

10

5

0

Chan

ge in

The

rmal

Gel

Tem

p.,°C

METHOCEL A4M(4,000 mPa.s)

METHOCEL F4M(4,000 mPa.s)

High-strength, water-soluble films,supported or unsupported, may be rolled, cast, or extruded fromformulations of METHOCEL cellulose ether products. These clear, smooth films or coatings are impervious to oils, greases, and most solvents. They are alsoeffective binders, even when loadedwith inert materials.

Tensile and elongation properties of typical films of METHOCEL cellulose ethers cast from water areshown in Table 9. The need for aplasticizer may be more pertinentwhen using low viscosity 5 mPa·sMETHOCEL cellulose ethersbecause of lower film elongationproperties. This can be more acute ifdrying temperatures are too high.

Effect of Additives on Film Solubility

The water solubility of films andcoatings of METHOCEL celluloseethers can be altered by the use of

cross-linking compounds and resins.The degree of insolubility can be controlled by the choice and quantityof a cross-linking reagent. All ureaformaldehyde, melamineformaldehyde, and resorcinolformaldehyde resins can be used.Dialdehydes such as glyoxal are alsoeffective. Supplier literature shouldbe consulted for selection ofcatalysts and curing compounds.

Resistance of Films to Solvents

Films and coatings of METHOCELare unaffected by animal and vegetable oils, greases, and petroleumhydrocarbons. Of the different types of products, METHOCEL A, METHOCEL F, and METHOCELK brand products are most resistant.

Thermoplastic Forming

Procedures for preparing a dry-mixformulation of METHOCEL E or J cellulose ether products withpropylene glycol and other plasticizers are available for extrudedsheeting and injection or compressionmolding. Such mixes may be compounded in a ribbon-typeblender at room temperature andsatisfactorily handled by a feederdesigned for powders. Most feedersperform better if the dry mix is firstdensified by being passed through a set of press rolls or through a pellet mill.

Flakes of METHOCEL E or J cellulose ether products withpropylene glycol and otherplasticizers may be extruded ormolded directly into a finished,water-soluble product attemperatures ranging from 80 to160°C (176 to 320°F). Properlyplasticized sheet and tubing ofMETHOCEL cellulose ether can beheat-sealed at about 130°C (266°F).

26

Table 9: Properties of Unplasticized Films of METHOCEL Cellulose Ethers

Propertiesa METHOCEL A15 LV METHOCEL E15 LV

Specific gravity 1.39 1.29Area factor 24,000 in2/lb/mil 25,860 in2/lb/milMoisture vapor

transmission rate, 100°F (38°C), 50% RH 67.5 g/100 in2/24 h/mil 65 g/100 in2/24 h/mil

Oxygen transmission rate, 75°F (24°C) 25 cm3/100 in2/24 h/mil 70 cm3/100 in2/24 h/mil

Tensile strength, 75°F (24°C), 50% RH 9,000 Ib/in2 (62 MPa)±10% 10,000 Ib/in2(69 MPa)

±10%Elongation,

75°F (24°C), 50% RH 5-15% 5-15%Stability to ultraviolet

light, 500 h, Fadeometer exposure Excellent Excellent

Resistance to oils and most solvents Excellent Excellent

Ultraviolet transmission (2 mil film)400 nm 55% 82%290 nm 49% 34%210 nm 26% 6%

aTypical properties, not to be construed as sales specifications. Data based on a 1 mil dry film.

Properties of Films of METHOCEL Cellulose Ethers

Measuring Viscosity

Certain precautions must beobserved for the accuratemeasurement of the viscosity ofsolutions of METHOCELcellulose ethers because theyexhibit a nonlinear shearstress/shear rate relationship,which results in pseudoplastic viscosity behavior at most shear rates.

Dow employs the ASTM referencemethod (D1347 and D2363) as itsstandard procedure. This methodinvolves the use of Ubbelohde viscometers, one type for low viscosities and another for high viscosities. The Ubbelohdeviscometer is a precision devicewhich requires only a small test sample.

For measuring low viscosity, theappropriate capillary tube size is chosen to obtain a flow time of 50 to 150 seconds (see Table 10). Theviscometer is placed in a 20°Cbath, and the length of timerequired to deliver a given volumethrough the capillary tube is measured. The time in seconds isthen converted to millipascal-seconds (mPa·s). Detailed procedures are given in currentASTM standards D1347 andD2363. The most reproducible viscosities are obtained by coolingto 4°C and holding for at leastone-half hour before testing at 20°C.

Viscosity may also be determinedusing a rotational viscometer suchas the Brookfield model LVF†

viscometer. When the viscosity of asolution is less than 500 mPa·s, theviscosity is less dependent on shear,and the solution may be regardedas near-Newtonian. The apparentviscosity of a solution of higherviscosity will be highly dependenton the rate of shear, decreasing asthe rate of shear is increased.

The rotational instrument shouldbe calibrated against standard oils. It’s important to note, however,that there is no direct correlationbetween Ubbelohde and Brookfieldmeasurements for non-Newtonianliquids. For details regardinganalysis methods, please contactyour local salesperson forMETHOCEL cellulose ethers.

27

Analytical Methods

†Brookfield Synchrolectric viscometer, BrookfieldEngineering Co., Stoughton, MA.

Table 10: Capillary Tubes for Measuring Viscosity

Viscosity, Size of Heavy Wall Tubing,mPa.s Inside Diameter

Low viscosity15 25100 400

High viscosity1,500 4,000 8,000 15,000 50,000 75,000

1.5 mm1.8 mm2.4 mm 3.2 mm

5.0 mm6.0 mm7.5 mm 10.0 mm15.0 mm15.0 mm

Published Analytical Methods

Procedures for the analysis ofMETHOCEL cellulose etherproducts have been standardizedunder ASTM D1372 and ASTMD2372. These and otherinformation on analysis are listedin the following references.

Methods for TestingMethylcellulose – Current ASTMD1372, American Society forTesting and Materials, 1916 RaceStreet, Philadelphia, PA 19103.

Methods for TestingHydroxypropyl Methylcellulose –Current ASTM D2372, AmericanSociety for Testing and Materials,1916 Race Street, Philadelphia, PA19103.

Methoxyl and HydroxypropyISubstitution in Cellulose EtherProducts by Gas Chromatography– Current ASTM D3876,American Society for Testing andMaterials, 1916 Race Street,Philadelphia, PA 19103.

Methylcellulose – Food Chemicals Codex, Washington,D.C., National Academy ofSciences and National ResearchCouncil, Current Edition.

Hydroxypropyl Methylcellulose –Food Chemicals Codex,Washington, D.C., NationalAcademy of Sciences and NationalResearch Council, Current Edition.

The Determination of Particle SizeDistribution of METHOCELCellulose Ethers – Dow MethodNo. Mc-l IA (1973).

Application of Anthrone Test toDetermination of CelluloseDerivatives in Nonaqueous Media– Aldrich, J.C., Samsel, E.P., Anal.Chem. 29, 574-76 (1957).

Hydroxypropyl Methylcellulose –The National Formulary, AmericanPharmaceutical Association,Washington, D.C., CurrentEdition.

Colorimetric Determination ofMethylcellulose withDiphenylamine – Danzaki, Grace,Berger, Eugene Y., Anal. Chem. 31,1383-5 (1959).

Colorimetric Method forDetermination of Sugars andRelated Substances – Dubois, M.,Gilles, K.A., Hamilton, J.K.,Repers, P.A., Smith, F., Anal.Chem. 28, 350-356 (1956).

Methylcellulose – U.S.Pharmacopoeia, Bethesda, MD,The United States PharmacopoeialConvention, Inc., Current Edition.

Determination of AlkoxylSubstitution in Cellulose Ethers byZeisel-Gas Chromatography –Hodges, K., Kester, W.,Wiederrich, D., Grover, J., Anal.Chem. 51, 2172-2176 (1979).

28

Material Safety Data Sheets/SafetyData Sheets for METHOCEL products are available from TheDow Chemical Company to helpyou further satisfy your own handling,disposal, and safety needs and thosethat may be required by governmentregulations. Such information shouldbe requested prior to handling oruse. The following comments aregeneral and are not a substitute forthe detailed safety informationfound in the Material Safety DataSheet/Safety Data Sheet.

Health

METHOCEL cellulose ether products resemble the naturallyoccurring plant and seaweed gumsin many of their chemical, physical,and functional properties. All ofthese materials possess a basic carbohydrate structure.

METHOCEL products have hadextensive evaluation and testing inboth acute and long-term feedingstudies in a number of species,including humans. Their many yearsof use in a wide variety of fooditems attests to the safety ofMETHOCEL Premium products.

Although dust from METHOCEL cellulose ether products could conceivably cause temporarymechanical irritation to the skin and eyes under extreme conditionsand may be considered a nuisancedust if inhaled, the products areconsidered to present no significanthealth hazard in handling. Pleasereview the handling precautionswithin the Material Safety DataSheet/Safety Data Sheet for more information.

Flammability

Cellulose ether products are organic polymers that will burnwhen exposed to heat and a sufficient oxygen supply. Fires can be extinguished by conventional

means, avoiding any raising of dust by strong water jets. Dow recommends the use of water spray, carbon dioxide, or powderextinguishers.

Storage

Caution: A fine dust of this materialis capable of forming an explosivemixture with air. Powder samplesshould not be exposed totemperatures above 135° to 145°C.Samples may decompose and lead toa possible dust explosion. As in storage of any dusts or fine powders,good housekeeping is required toprevent dusts in air from reachingpossibly explosive levels. When handling in large quantities or inbulk, the general precautions outlined in NFPA 63, “Prevention of Dust Explosions in IndustrialPlants,” and in NFPA bulletins 68,69, and 654 are recommended.

With METHOCEL cellulose etherproducts with particle sizes of 74µm or less (finer than 200 mesh),critical levels are reached atconcentrations of 28 g/m3 (0.03oz/ft3). The minimum ignitionenergy required to cause a dustexplosion is 28mJ. Static from ahuman body has about 25mJ. Thisis normally not enough energy toignite the powder.

As with any organic chemical material, METHOCEL celluloseethers should not be stored next toperoxides or other oxidizing agents.

Accidental Spills and Housekeeping

Solutions of METHOCEL celluloseethers are slippery. To preventemployee falls and injury, floor spillsof dry powder should be thoroughlyvacuumed or swept up. Any slightresidual product on the walls orfloor can then be flushed with waterinto a sewer. If the spill is a viscoussolution, it should be further diluted

with cold water before disposal.Likewise, accumulation of dustshould be avoided to control this hazard.

Disposal

Despite the very slow rate ofbiodegradation, cellulose ether products should not present anyhazard in the waste/soil compartment.Their behavior is similar to wheatflour or sawdust. Although Dowstudies using standard proceduresshowed no 5-day, 10-day, or 20-dayBOD values, activated sludge studieswith (14C) methylcellulose showedthat methylcellulose was 96%degraded or otherwise removedfrom solution in 20 days. Thus,METHOCEL cellulose ethers shouldpresent no ecological hazard toaquatic life.

Because METHOCEL celluloseether products and their aqueoussolutions present no significant ecological problems, they can be disposed of by industrial incinerationor in an approved landfill, providingregulations are observed.Incineration should be done undercarefully controlled conditions toavoid the possibility of a dust explosion. Customers are advised toreview their local, state, provincial or national regulations governing the disposal of waste materials todetermine appropriate means of disposal in their area.

Customer Notice

Dow encourages its customers toreview their applications of Dow products from the standpoint ofhuman health and environmentalquality. To help ensure that Dowproducts are not used in ways forwhich they are not intended or tested, Dow personnel will assistcustomers in dealing with ecologicaland product safety considerations.Please contact us at the numberslisted on the back cover.

29

Handling Considerations

NOTICE: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from onelocation to another and may change with time, Customer is responsible for determining whether products and the information in this document areappropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and othergovernmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALLIMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

Printed in U.S.A. *Trademark of The Dow Chemical Company Form No. 192-01062-0902 AMSPublished September 2002

For more information, complete literature, and product samples, you canreach a Dow representative at the following numbers:

From the United States and Canada:call 1-800-447-4369fax 1-989-832-1465

In Europe:toll-free +800 3 694 6367†

call +32 3 450 2240fax +32 3 450 2815

From Latin America and Other Global Areas:call 1-989-832-1560fax 1-989-832-1465

www.methocel.com

†Toll free from Austria (00), Belgium (00), Denmark (00), Finland (990), France (00), Germany (00), Hungary (00), Ireland (00), Italy (00),

The Netherlands (00), Norway (00), Portugal (00), Spain (00), Sweden (00), Switzerland (00) and the United Kingdom (00).