for Adhesive Tapes andother Products

By Shrikant AthavalePrathith ConsultantsPune MS. India

By Shrikant AthavalePrathith ConsultantsPune MS. India

The release coatings are also called as Abhesive

The coating that is used to prevent or greatly decrease adhesion , is termed as Abhesive

The coated abhesive , creates a surface that discourages adhesion.

Abhesive materials are also often referred to as mold-release agents, non-stick surface coatings, parting agents, or antistick agents. Abhesion is exactly the opposite of adhesion, and the requirements for a good abhesive

The applications for abhesives are nearly as numerous and as commercially important as they are for adhesives.

The most recognizable abhesives are used as mold release surfaces and as liners for pressure sensitive tapes and labels.

A variety of materials and processes have been developed to provide surfaces that function as abhesives.

However, the main purpose of this review will be to explain the material and surface science fundamentals required for an abhesive to function.

Mechanism

In order to understand how abhesives work, In order to understand how abhesives work,

Let us understand the mechanism of adhesion and the factors that affect it.Let us understand the mechanism of adhesion and the factors that affect it.

Adhesion occurs through a: mechanical interlocking, interdiffusion,adsorption (surface reaction), and electrostatic attraction.

Adhesion occurs through a: mechanical interlocking, interdiffusion,adsorption (surface reaction), and electrostatic attraction.

adhesion depends on the surface topology, surface tension and energy,wetting, andthermodynamic work of adhesion.

Therefore, surface treatment is required to enhance adhesion .

This is done by

removing weak boundary layers, changing surface topography, changing the chemical nature of the surfaces, and modifying the physical structure of the surface.

Therefore, surface treatment is required to enhance adhesion .

This is done by

removing weak boundary layers, changing surface topography, changing the chemical nature of the surfaces, and modifying the physical structure of the surface.

Abhesion

requires just the opposite. For maximum abhesion, or resistance toadhesion, the surface should exhibit the following characteristics.

1. A barrier to mechanical interlocking 2. Prevention of interdiffusion 3. Poor adsorption and surface reaction 4. Low surface tension and thermodynamic work of separation 5. Limited or no electrostatic attraction 6. Incorporation of a weak boundary layer.

Abhesion

requires just the opposite. For maximum abhesion, or resistance toadhesion, the surface should exhibit the following characteristics.

1. A barrier to mechanical interlocking 2. Prevention of interdiffusion 3. Poor adsorption and surface reaction 4. Low surface tension and thermodynamic work of separation 5. Limited or no electrostatic attraction 6. Incorporation of a weak boundary layer.

Since many of the factors causing adhesion are of a chemical nature, a good abhesive must also be chemically inert toward the two materials whose adhesion are to be prevented.

Abhesion, therefore, occurs via one of two primary modes: (1) prevention of adhesion to the abhesive coating layer, or(2) an easily separable coating or cohesively weak boundary layer.

Thus, there are several ways in which abhesives can be classified. The most popular classifications are permanent (corresponding to 1 above) and sacrificial (corresponding to 2 above).

Several examples of each are readily evident in the household environment. The coating on a non-stick baking pan is an example of permanent abherend.

Flour, grease, or oil used for non-stick baking are examples of sacrificial abherends. of release.

Permanent abherends require that the abhesive material have good spreading tendency on the material to be protected and a surface that exhibits poor spreading tendency to the material which adhesion is to be prevented.

The permanent abherend must be a good coating material (i.e., easily applied, uniformly spread over the surface to be protected, and relatively permanent during all expected processes).

Sacrificial abherends require only that the abhesive material fill the pores or smooth-out the roughness of a surface (e.g., an inert powder on a rough metal surface).

Sacrificial abherends generally remain attached to both surfaces after release, and they must be applied to a surface every time it is to be protected. On the other hand, permanent abherends will last through many cycles of release.

An important factor in choosing an abhesive is temperature dependence.

A material could act as an abhesive at room temperature and as an adhesive at elevated temperatures.

Thermoplastic polyethylene coatings are good examples of this.

Polyethylene is relatively inert with a low surface energy, non-stick surface in its solid state, but it has good adhesive properties in the molten state.

Another factor to be considered in choosing an abhesive is volatility.

Water would be a good abhesive, but because it vaporizes at relatively low temperatures, water could not be used as a mold release in many high temperature applications.

Theory

Two solid materials generally do not adhere to each other because wetting does not take place and there is no penetration or interdiffusion of one material into the other.

When wetting is minimal, the secondary van der Walls bond forces that provide the majority of molecular adhesion are not large, the work of adhesion is minimal, and the surface has the properties of a good abherend.

Wetting can be determined by contact angle measurements

Two solid materials generally do not adhere to each other because wetting does not take place and there is no penetration or interdiffusion of one material into the other.

When wetting is minimal, the secondary van der Walls bond forces that provide the majority of molecular adhesion are not large, the work of adhesion is minimal, and the surface has the properties of a good abherend.

Wetting can be determined by contact angle measurements

A simple view of the relationship of wetting and adhesion is provided by Figure 1. Here the contact angle of a drop of a liquid on a surface of different critical surface tension is shown. The expected bond strengths would increase as the contact angle decreases. Therefore, best abhesive scenario is when the contact angle is greatest.

Figure 1: Interaction of the same liquid with surfaces of different surface tension (mJ/m2 = dyne/cm).

After intimate contact is achieved between adhesive and adherend through wetting, it is believed that permanent adhesion results primarily through forces of molecular attraction. Four general types of chemical bonds are recognized as being involved in adhesion and cohesion: electrostatic, covalent, and metallic, which are referred to as primary bonds, and van der Walls forces that are referred to as secondary bonds.

There are many materials that can be used as abhesives. These are generally classified chemically as shown in Table 1. They can be supplied in many different forms such as fluids, waxes, greases, emulsions, dry films, and solid powders. Many commercial abhesives are of proprietary composition. These products can be formulations of more than one type of abhesive with modifiers or additives, such as emulsifiers, biocides, solvents, etc., incorporated into the final product.

Types of Abherend materials

Chemical Class Chemical Subdivision

Specific Examples<

Waxes

Petroleum waxesParaffin wax, microcrystalline wax

Vegetable waxes Carnauba wax

Animal waxes Lanolin

Synthetic waxes Polyethylene wax

Fatty acid metal soaps

Metal stearates Magnesium stearate, zinc stearate

Others Calcium ricinoleate

Long chain alkyl derivatives

Fatty ester synthetic waxes

Diethylene glycol monostearate, hydrogenated castor oil

Fatty acids Stearic acid, oleic acid

Fatty amidesEthylenebis(stearamide), oleyl palmitamide

Natural products

Cellulose derivatives Cellophane, cellulose acetate

Polysaccharides Sodium alginate

Inorganic materials

Silicates Talc

Clay Kaolin, mica

Other Silica, graphite

Synthetic polymers

SiliconesPolydimethylsiloxane, polyalkylmethylsiloxane

Fluorocarbons Polytetrafluoroethylene

Other fluoropolymers

Poly(fluoroacrylates), poly(fluoroethers)

Polyolefins Polyethylene, polypropylene

Other Polyvinyl alcohol

Fluorinated compounds

Fluorinated fatty acids and alcohols

Perfluorolauric acid

All abhesive materials are characterized by providing a low energy surface, and any liquid placed on such a surface will exhibit a contact angle, which will be larger as - increases. When is large enough, such poor adhesion will occur that the application of a modest external stress will cause the bond to separate. Table 2 gives values of for common abhesive materials.

AbherendSurface Tension,dyne/cm

Carnauba wax 38

Paraffin wax 23

Fatty acid monolayer 24

Polyethylene 25-36

Polypropylene 29-34

Polymethylsiloxane film 24

Polymethylsiloxane fluid 20

Polyvinyl fluoride 28

Polyvinylidene fluoride 25

Polytetrafluoroethylene 18.5

Fluoroethylene propylene 16

Perfluorolauric acid monolayer 6

Silicone oil 21

Petroleum lubricating oil 29

Now BASF – India and Prathith Consultants , offer a water based Release coating agent ( Non Silicone ) for backsizing applications, in the manufacture of Self wound Self adhesive Tapes.There a number of applications for our product. The Prdost Data sheet as wellas the variety of applications for the same , are shown in the slides to follow.

Technical InformationTechnical Information

Contact UsContact Us

This is an aqueous, finely divided emulsion of a very hard poly- ethylene wax with a high melting point. It is manufactured under pressure by means of a special BASF process.This conforms to the requirements of various FDA regulations on account of its chemical composition and the process by which it is manufactured.Microbial attack This is fully protected against microbial attack during transport, but biocides need to be added in order to prevent problems with microorganisms from occurring during storage and processing. Careful attention has to be paid to the hygiene of storage facilities.Low-temperature stability It is not advisable to store This in the open during winter. Measures should be taken to prevent it from freezing. If it does freeze, the best course of action is to thaw it gradually by leaving it to stand at room temperature. It should not be heated directly. It is advisable to filter reconstituted dispersions before use.Shelf life This has a shelf life of one year in its sealed original packaging, provided it is stored properly. Drums should be tightly resealed each time material is taken from them. We would recommend filtering this product before use if it has been left in storage for long periods or if a crust has formed on the surface due to the evaporation of water.

This is an aqueous, finely divided emulsion of a very hard poly- ethylene wax with a high melting point. It is manufactured under pressure by means of a special BASF process.This conforms to the requirements of various FDA regulations on account of its chemical composition and the process by which it is manufactured.Microbial attack This is fully protected against microbial attack during transport, but biocides need to be added in order to prevent problems with microorganisms from occurring during storage and processing. Careful attention has to be paid to the hygiene of storage facilities.Low-temperature stability It is not advisable to store This in the open during winter. Measures should be taken to prevent it from freezing. If it does freeze, the best course of action is to thaw it gradually by leaving it to stand at room temperature. It should not be heated directly. It is advisable to filter reconstituted dispersions before use.Shelf life This has a shelf life of one year in its sealed original packaging, provided it is stored properly. Drums should be tightly resealed each time material is taken from them. We would recommend filtering this product before use if it has been left in storage for long periods or if a crust has formed on the surface due to the evaporation of water.

Applications

This is particularly versatile on account of the balanced combination of hardness, toughness and elasticity of the polyethylene wax on which it is based.

 Overprint varnishes The wax contained in this is very hard, which makes it very effective in overprint varnishes applied to paper and plastic film in the packaging industry, etc. It usually needs to be applied at a rate of 8 – 10 %, expressed as a proportion of the overall formulation.

Paper and board this coating , because of the hardness of the wax on which it is based, can be used in combination with film-forming agents to increase the resistance of paper to scratching and mechanical action. conforms to the requirements of various FDA regulations concerning coatings applied to paper and board for food-contact applications. Polyurethane coatings This coating is very effective for improving the scratch resistance ofwater-based polyurethane coatings, such as those applied to parquet floors. Printing inksThis coating can be added to water-based printing inks to improve their abrasion resistance. It also reduces the sliding friction of printed surfaces. 

 Textile finishingThe high hardness and the low friction of the wax contained in, combined with the very high stability of dilute emulsions, makes it very effec- tive in finishes applied to textile fabrics in order to improve their sewability, abrasion resistance and tear resistance, etc. Floor polishes Dry-bright polishes can be formulated with in combinationwith styrene-acrylic polymer dispersions. The wax contained in is very hard and tough, and this enables dry-bright films with exceptionally hard-wearing films with high traffic resistance to be obtained. is compatible with all conventional polymer dispersions, resin solutions, plasticizers, film-forming agents and surfactants. 

FDA Paragraph 21 CFR 175.105 Adhesives 176.170 Components of paper and paperboard in contact with aqueous and fatty foods 176.180 Components of paper and paperboard in contact with dry food 177.1390 High-temperature laminates  www.basf.com/detergents-formulators

FDA Paragraph 21 CFR 175.105 Adhesives 176.170 Components of paper and paperboard in contact with aqueous and fatty foods 176.180 Components of paper and paperboard in contact with dry food 177.1390 High-temperature laminates  www.basf.com/detergents-formulators

Safety

We know of no ill effects that could have resulted from using this coating for the purpose for which it is intended and from processing it in accordance with current practice. According to the experience that we have gained over many years and other information at our disposal, this does not exert any harmful effects on health, provided that it is used properly, due attention is given to the precautions necessary for handling chemicals, and the information and advice given in our safety data sheet are observed.

 

Safety

We know of no ill effects that could have resulted from using this coating for the purpose for which it is intended and from processing it in accordance with current practice. According to the experience that we have gained over many years and other information at our disposal, this does not exert any harmful effects on health, provided that it is used properly, due attention is given to the precautions necessary for handling chemicals, and the information and advice given in our safety data sheet are observed.

 

Note The data contained in this publication are based on our current knowledge and experience. In view of the many factors that may affect processingand application of our product, these data do not relieve processors from carrying out their own investigations and tests; neither do these data imply any guarantee of certain properties, nor the suitability of the product fora specific purpose. Any descriptions, drawings, photographs, data, pro- portions, weights etc. given herein may change without prior information and do not constitute the agreed contractual quality of the product. It is the responsibility of the recipient of our products to ensure that any proprietary rights and existing laws and legislation are observed. 

Note The data contained in this publication are based on our current knowledge and experience. In view of the many factors that may affect processingand application of our product, these data do not relieve processors from carrying out their own investigations and tests; neither do these data imply any guarantee of certain properties, nor the suitability of the product fora specific purpose. Any descriptions, drawings, photographs, data, pro- portions, weights etc. given herein may change without prior information and do not constitute the agreed contractual quality of the product. It is the responsibility of the recipient of our products to ensure that any proprietary rights and existing laws and legislation are observed. 

Here are some specialty Tapes , self wound , that need , a easy release , on unwinding.There are lot may options available as of today.We have now something to offer Ex. Stock, water borne.

Here are some specialty Tapes , self wound , that need , a easy release , on unwinding.There are lot may options available as of today.We have now something to offer Ex. Stock, water borne.

For Fabrics based Tapes

For Fabrics based Tapes

Uni and Bi directional Polyester TapesUni and Bi directional Polyester Tapes

Fibre Glass Cloth TapesFibre Glass Cloth Tapes

For Foil / Alu Glass Tapes

For Foil / Alu Glass Tapes

Aluminium Foil TapesAluminium Foil Tapes

Alu Glass TapesAlu Glass Tapes

For Pet / PE , film based Tapes

For Pet / PE , film based Tapes

PET Holding Tape

PET Holding Tape PE Surface

Protection Tape

PE Surface Protection Tape

PET Electrical Insulation Tape

PET Electrical Insulation Tape

PET Application Tape

PET Application Tape

For BOPP , film based Tapes , with HM Adhesive

For BOPP , film based Tapes , with HM Adhesive

Adhesive Coating station

Adhesive Coater for self wound Tapes with our backsizing solutionAdhesive Coater for self wound Tapes with our backsizing solution

The requirements of ,Backside non- Silicone release coating ( which is also termed as Abhesive ) are,

1.It has to be quick drying.2.It must be non curing type , no chemical reaction or Cross linking is involved.3.Very very low coat weight.4.Should not interfere with the PS Adhesive , or lower the peel adhesion , due to unwanted pick up of the release coating by adhesive5.Must be cost effective6.Ability to coat in single pass , along with adhesive.

The requirements of ,Backside non- Silicone release coating ( which is also termed as Abhesive ) are,

1.It has to be quick drying.2.It must be non curing type , no chemical reaction or Cross linking is involved.3.Very very low coat weight.4.Should not interfere with the PS Adhesive , or lower the peel adhesion , due to unwanted pick up of the release coating by adhesive5.Must be cost effective6.Ability to coat in single pass , along with adhesive.

The Advantages of our Non Silicone Release Coat (Poligen WE 6 )

Ex Stock availabilityPurely water based Quick dryingVery cost effective as compared to Imported products Especially highly suitable for the manufacture of Surface protection Tapes on , co-extruded Poly Ethlene Films

contact us on

Email : shrikantathavale@psadhesive.comOr Mobile : 07588288204Email : Shyam.devikar@basf.com

OrVisit us on : www.psadhesive.com

For more details on the TDS , Free sample for machine trials , assistance for machine trials, minor machine modifications etc.,