New Developments in Aromatic Curative Technology · New Developments in Aromatic Curative Technology Yong Tang, ... Curative Blend 1, PPT-80a, DOP 0 wt% 7 wt% 16 wt% 28 wt% PDA Europe

PDA Europe 2014 Annual Conference – Krakow, 5-7 November

New Developments in Aromatic

Curative Technology

Yong Tang, Ph.D.


Outline

• Hand Applied Roof Coating

» MOCA replacement

» Development of new curative package with use of Design of Experiment

(DOE)

• Use of these new curative package (E500 series curatives)

» Spray polyurea coatings

» Cast elastomers

• Conclusions


• Global provider of specialty chemicals products. Headquartered in Baton Rouge, LA,

USA.

• Diversified mix of solution-based products and custom services sold to a wide range of

customers and end markets.

» Over 3,000 customers in 100 countries; Over 3,500 employees around the world.

» Operate 40+ facilities encompassing production, R&D, and administrative.

offices in North and South America, Europe, the Middle East and Asia.

• Two global business units:

» Catalyst Solutions

» Performance Chemicals

Catalysts 38%

Bromine Derivatives

36%

Mineral FR 6%

Stabilizers & Curatives

9%

Fine Chemstry Services

11%

Strong History of Growth

Albemarle Corporation


Background

• MOCA is one of the most commonly used curatives in PU, due to cost and performance, however represents a significant hazard to workers. The sun-set day of MOCA is 22 Nov 2017.

• New regulations in the world (REACH, China, etc.) driving very high costs and long time frames for registration of new chemicals.

• Blending of registered products is a cost effective and rapid way to explore new applications, which can provide potential alternatives to MOCA.

• New curative applications:

» Coatings (spray or hand applied)

• Protect concrete roofs and decking

• Waterproofing required

» Cast Elastomers

» Adhesives and Sealants


Japan Roofing Market

• The Japan roof coating market is about 50% asphalt technology, 30% PU

coatings and 20% PVC sheeting.

• Market shares have roughly stayed the same for the last 10 years. Total

market size is flat.

• MOCA is the dominate curative for the PU coating due to cost and

performance. The largest application for MOCA in Japan is

for PU Roof Coatings, about 1500 tons/y.

50%

20%

30% Asphalt Technology

PVC sheeting

PU coating


Roofing Materials and Hand Applied

System in Japan

• Material classifications

» Urethane system

» Acrylic system

» Chloroprene system

» Asphalt system

• Hand applied system two-component

» A side: TDI based prepolymer

» B side: curative (i.e. MOCA)

Japan Roof Coating


Roof Coating Physical Property Targets

Property Target

Pot-life (min)† 60-90

Hardness (Shore A) † 30-70

Tensile Strength (psi) ‡ >355

Tear Strength (lb/in) ‡ >84

% elongation‡ >450%

† customer specifications

‡ Japanese Industrial Standard: JIS A 6201


Current Curative System in Japan PU Roofing

• MOCA in 2K polyurethane coating

» Methylene bis(ortho-chloroaniline)

» Used to cured TDI-based isocyanate prepolymer

» Long pot-life (~60-90 minutes)

» Gives desired physical properties

H2N NH2

ClCl


MOCA Toxicity

• In 2010, IARC reclassified MOCA from a Class 2a carcinogen

(probably causes cancer) to a Class 1 carcinogen (known to cause

cancer). (IARC, vol. 57, vol. 99, in prep.).

• Potential worker exposure to MOCA in Japanese roof coating.

• Need to develop alternative curative technology to MOCA

delivering desired performance.

» Easy application

» Long pot life

» Desired physical properties


Experimental

A-side

• TDI-based

• 3.6% NCO

• liquid at RT

B-side

• Amine

• Plasticizer (DOP)

• Filler

Dual-axis high speed mixer Draw-down mold

Material Source

3.6% NCO TDI Prepolymer Air Products Airthane ® PPT-80A

DETDA (E100) Albemarle

DMTDA (E300) Albemarle

Calcium carbonate Aldrich

Dioctyl phthalate Aldrich

• Materials

• Equipment

Brookfield DV-I Viscometer


Test Methods

• Coating Physical Properties:

» Room temperature cure

• Demold after 1d

• Testing after 7days in condition room

» Shore A hardness (ASTM 2240)

» Tensile strength and elongation (ASTM D-412)

» Pot-life: Brookfield viscometer (100, 000 cPs)


Results – Quick Screen

• DMTDA has extended pot-life, but lower physical properties

• DETDA is too fast, but delivers good physical properties

• SBMDA did not cure (>24 hrs)

• Initial Screening blends achieved desired pot-life, but mechanical properties didn’t meet the targets

Curative Pot life (min) Hardness (Shore A) Tensile (psi) Elongation (%)

Target 60-120 35-50 >362 >450

MOCA/PPG 2000 50-120 44-60 272-500 500-1200

DMTDA (E300) 300 50 169 57

DETDA (E100) 18 72 617 479

SBMDA (E420) Did not cure

Screening Blend 1 60 52 355 535

Screening Blend 2 89 57 280 439


Pot Life Measurement

0

50.000

100.000

150.000

200.000

250.000

0 50 100 150 200 250 300 350

Vis

cosity (

cP

)

Time (minutes)

Viscosity Rise of Coatings

E100 Screening blend 1 Screening Blend 2 E300

Time until

viscosity

reaches

100,000cP


Use of Plasticizers Common in PU Coating

Formulations

• Pot life and elongation increased, but tensile strength decreased

Wt% DOP

in coating 0% 7% 16% 28% Target

Pot Life (min) 21 29 44 51 60-90

Hardness (Shore A) 62 57 52 60 >45

Tensile (psi) 662 632 597 578 >362

Elongation (%) 342 360 423 611 >450


Effect of Plasticizer on Pot Life

0

50.000

100.000

150.000

200.000

250.000

0 10 20 30 40 50 60 70

Vis

cosity (

cP

)

Time(min)

Viscosity Rise as Plasitcizer Added Curative Blend 1, PPT-80a, DOP

0 wt% 7 wt% 16 wt% 28 wt%


Effect of Plasticizer

0 wt.% DOP

6 wt.% DOP

17wt.% DOP


Effect of Iso/Amine Ratio (Index)

0

100

200

300

400

500

600

700

800

900

0,90 0,95 1,00 1,05 1,10 1,20 1,30

Tensile Strength and % Elongation Curative Blend 1, PPT-80 Index Scan

Tensile (psi) Elongation (%)


Effect of Iso/Amine Ratio (Index)

0,9

1

1,1

1,2

1,3

30

35

40

45

50

55

0,85 0,95 1,05 1,15 1,25 1,35

Po

t-lif

e (

min

ute

s)

Index

Pot-life vs. Index


Need to Develop New Approach

• A need exists - customers want to eliminate MOCA use in

these PU roof coatings.

• But after 10+ years of formulation effort by Japanese customers

and suppliers, no single amine curative system has been able

to deliver the cure speed and physical properties of MOCA.

• Screening blends are able to achieve desired pot life, but

mechanical properties still need to be improved.

• Need to develop new approach to find alternative curative

technology to MOCA.


Use of Design of Experiment (DoE) Software

• Use multi-component blends of registered amine curatives

• DoE Software: Minitab 15

» Factor levels determined in this quick screen

• Index: 1 to 1.3

• Plasticizer: 7 to 16 wt.% in total coating formulation

• Curative B: 50 to 67% in curative blend

» Factorial

• 2-level

• 3 factors

• 8 runs, 1 replicate


DoE Results – Pot Life

Index

Pla

sticiz

er

Index

Cu

rative

B

Plasticizer

Cu

rative

B

Contour Plots of Pot Life

• Index, plasticizer, and wt.% curative B all increase pot-life

Target: 60-90


DoE Results – Tensile Strength

Index

Pla

sticiz

er

Index

Wt.

% C

ura

tive

B

Plasticizer

Wt.

% C

ura

tive

B

Contour Plots of Tensile

Target >355

• Plasticizer * index plot shows slight curvature, indicating slight interaction

• Curative B * index and curative B * plasticizer do not interact to affect tensile


DoE Results - % Elongation

Contour Plots of Elongation

Index

Pla

sticiz

er

Index

Wt.

% C

ura

tive

B

Plasticizer

Wt.

% C

ura

tive

B

Target >450

• Lines are curved, indicating strong interactions between variables.

• The effect of plasticizer and curative B loading are stronger at a 1.0 index than at

1.3; at lower plasticizer loading, the curative B has a greater impact on elongation.


DoE Results - Hardness

Contour Plots of Hardness

Index

Pla

sticiz

er

Index

Wt.

% C

ura

tive

B

Plasticizer

Wt.

% C

ura

tive

B

Target >30-70

• The lines are generally straight, except sight curvature for curative B * plasticizer

interaction


Optimized Blend

Summary

• DoE very effective and powerful technique

for optimizing the formulation

• Actual results have good correlation

with predicted results

Curative B Plasticizer Properties

Desired Predicted Actual*

Pot Life (min) 100 99.9 102

Tensile (psi) >356 373 478

% elongation >451 471 605

Hardness (A) 35-50 42 47


Status

• DoE effectively used to create two new curative blends which

met all of the desired properties of MOCA.

• These two blends (E520 and E534) have been commercialized

and are being used hand applied coatings (i.e. roofing coatings).

• Now looking at curative blends for other PU applications.

» Spray polyurea coating

» Cast elastomer


Low Pressure Static Mixed Spray System

Tests:

• Tensile

• Tear

• Hardness

• Adhesion


Mechanical Properties of Spray Coating

Containing E420 and E500 Curatives

Formulation Δ E420 E520 E534

Gel Time(S) 27 24 27

Tensile (psi) 1300 1512 1627

Modulus (psi) 5558 7613 7772

Elongation % 416 385 433

Tear resistance (lbf/in) 357 368 409

Hardness (shore A) 79 82 82

Adhesion (psi) @ 215 224 220

Δ The equivalent ratio between E420/E100 and E500/E100=1/1;

@ The adhesion test was conducted with hardy board without base coating.


Physical Properties of Spray Coating with

Varying Equiv Ratio of E100/E520

Formulation 1 2 3 4 5 6

Equiv.ratio

E100:E520 80:20 70:30 60:40 40:60 30:70 20:80

Gel time (sec) 6.2 12 32 59 75 97

Tensile (psi) 1738 2208 1395 1320 1350 1187

Modulus (psi) 8755 9534 6871 6130 6004 5013

Elongation % 407 432 337 339 395 372

Tear resistance (lbf/in) 381 466 370 347 337 310

Hardness (shore A) 92 92 88 88 85 84

• Gel time increases with increase of E520 in B side

• The mechanical properties have the maximum values at Equiv ratio of E100/E520=70/30; and minimal values at 20/80.


Mechanical Properties of Cast Elastomers

Containing E500 Curatives

Sample Tensile

(psi)

Elongation

(%)

Young’s

Modulus

(psi)

Hardness

(shore A)

Compression

set %

Resilience

%

Tear Resistance

(lbf/in)

TDI-wt.4% NCO/E520-1.05 2498 449 399 67 60 54 207.

TDI-wt.4% NCO/E534-1.05 3688 440 732 69 63 51 256

TDI-6 wt.% NCO /E534-1.1 5456 341 1363 73 51 24 319

TDI-6 wt.% NCO /E534-1.2 5043 327 1310 80 63 21 287

MDI- 4wt.% NCO/E520-1.05 3194 540 480 66 43 23 264

MDI-4wt.%NCO/E534-1.05 4157 464 697 71 46 / 356

MDI-4wt.%NCO/E520-1.2 5126 453 1004 71 53 25 341

MDI-6wt.%NCO/E534-1.1 6588 424 1193 73 47 17 /

• Deliver considerable tensile strength, but the hardness still needs to be optimized. • MDI/E500 gives better performance compared with TDI/E500 system


Comparison of UV Performance

of E300 and E500

E300 E520 E300 E520

300 hrs UV exposure

ΔE E300=61.2

ΔE E500=32.9

Before UV exposure After UV exposure

E500 exhibits better weatherability compared with E300.


Conclusions

• Demonstrated it is possible to design blends of amine curatives to produce

coatings with similar pot-lives and physical properties as coatings cured with

MOCA.

• These blends are liquid and have an improved HSE profile versus MOCA and

thus provide viable alternatives.

• Used DoE to predict a formulation that met and exceeded

performance targets.

• E500 series curatives exhibit great potential in spray polyurea coating. The

cast elastomer made of E500 series curatives deliver considerable tensile

strength, but the hardness still needs to be optimized by special selection of

prepolymer blends to match the application. E500 curatives have better

weather ability compared with E300.

• Future work will be to apply this approach to developing new products in other

polyurethane markets.


Thank You!

Yong Tang, Ph.D.

Sr. R & D Engineer

[email protected]

225-359-2215

Paul Wiggins, Ph.D.

R & D Advisor

[email protected]

225-359-2017

w w w . a l b e m a r l e . c o m

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Documents

New Developments in Aromatic Curative Technology · New Developments in Aromatic Curative Technology Yong Tang, ... Curative Blend 1, PPT-80a, DOP 0 wt% 7 wt% 16 wt% 28 wt% PDA Europe