Vibrathane A TDI-terminated polyester based prepolymer

Transcription

1 199 Benson Road Middlebury, CT USA Effective: Vibrathane 8070 A TDI-terminated polyester based prepolymer VIBRATHANE 8070 is a TDI-terminated polyester based prepolymer which yields a 70 Shore A hardness urethane when cured with 4-4 -methylene bis-(orthochloroaniline), commonly called MBCA. Vibrathane 8070 elastomers are characterized by: High tensile and tear strength. Excellent heat, fuel and solvent resistance. Outstanding abrasion resistance. Good low temperature and dynamic properties. Vibrathane 8070 contains a small quantity of free toluene diisocyanate (TDI) which causes severe irritation to the eyes, skin, mucous membranes, and respiratory system. Avoid contact with eyes, skin and clothing, and wash thoroughly after handling. Avoid breathing vapor. Use only with adequate ventilation. In the USA, employee exposure to TDI is regulated by OSHA. Other materials that may be used with VIBRATHANE 8070 in the manufacture of finished products may present hazards in handling and use. Before proceeding with any compounding or processing work, consult and follow label directions and handling precautions from suppliers of all ingredients. The information contained herein relates to a specific Chemtura product and its use, and is based on information available as of the date hereof. Additional information relating to the product can be obtained from the pertinent Material Safety Data Sheets. NOTHING IN THIS TECHNICAL DATA SHEET SHALL BE CONSTRUED TO CONSTITUE A REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, REGARDING THE PRODUCTS CHARACTERTICS, USE, QUALITY, SAFETY, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Nothing contained herein shall constitute permission or recommendation to practice any intellectual property without the permission of the owner. Chemtura and the Chemtura logo are trademarks of Chemtura Corporation or one of its subsidiaries. Copyright 2007 Chemtura Corporation. All rights reserved. Page 1

2 LIQUID PREPOLYMER SPECIFICATIONS % NCO Amine Equivalent C Solid free from contamination Color, Gardner Melt Range C Brookfield Viscosity, poise 100 C (212 F) Specific Gravity at: 70 C (158 F) C (212 F) Typical Properties Viscosity, Centipoise (Pa 140 F (60 C) F (70 C) F (80 C) F (100 C) (1.0) Recommended Meltdown Procedure Devices such as melting ovens, thermostatically controlled warming blankets, or drum heaters can be used for melting Vibrathane Approximate meltdown times at 70 C (158 F) are: 5 gallon pail...16 Hours 55 gallon drum Hours Resins exposed to temperatures lower than 24 C (75 F) during shipment and/or storage may require longer melt down times. It is recommended that containers of Vibrathane 8070 be rolled prior to use to insure homogeneity. Copyright 2007 Chemtura Corporation. All rights reserved Page 2

3 Vibrathane 8070, like other very low NCO prepolymers, is less tolerant to NCO changes due to exposure to moisture and heat than high NCO resins. As a result, exposure to these conditions must be carefully controlled. Processing Conditions VIBRATHANE 8070, C ( F) ( ) MBCA Temperature, C ( F) ( ) Mold Temperature, C ( F) (212) Typical Pot Life*, Mins Cure, Mins./ C ( F)... 60/100 (212) Postcure, Hrs./ C ( F)... 16/100 (212) * Time to 200 Poise, 350g Scale, theory: Vibrathane C (212 F); 116 C (240 F). Mixing and Curing The temperature at which the curing reaction takes place has an important effect on the final hardness of Vibrathane 8070 as well as other prepolymers in the lower NCO ranges. The curing reaction begins the moment MBCA is mixed with Vibrathane 8070, and continues throughout the fluid stage and beyond the point of solidification until the urethane is completely cured. The reaction between Vibrathane 8070 and MBCA is exothermic. The temperature of the mass rises about 30 C when the reaction is carried out at recommended processing temperatures and in an insulated container. This represents the maximum temperature rise for the largest castings, since very little heat can escape. The actual temperature reached is influenced by several factors: 1. Temperature of prepolymer and curing agent. 2. The mold material and configuration. 3. The mold temperature and oven temperature. The size of the casting also has an effect since small castings can lose heat to the surroundings more easily than large ones. The effect of mold and curing temperature on the hardness of Vibrathane 8070 is illustrated in the following table: Copyright 2007 Chemtura Corporation. All rights reserved Page 3

4 Effect of Mold and Postcure Temperature 1 Mold and Cure Temp., C ( F) 2 82(180) 100(212) 104(220) 82(180) 100(212) 104(220) Postcure Temp. (16 Hrs.) C ( F) 70(158) 70(158) 70(158) 100(212) 100(212) 100(212) Final Hardness, Shore A Prepolymer Temperature = 100 C (212 F) MBCA (90% of theory) Temp. = 116 C (240 F) 2 One hour at specified temperature When hardness of the elastomer is critical, we recommend that close attention be paid to mold and curing temperatures. For further recommendations and assistance, contact Adiprene/Vibrathane Technical Service: Effect of MBCA Level on the Physical Properties 3 of Vibrathane 8070 Vibrathane 8070 (NCO = 2.50%) MBCA % Theory Shore A Hardness % Modulus, Psi (MPa) 310 (2.1) 330 (2.3) 370 (2.5) 270 (1.9) 260 (1.8) 300% Modulus, Psi (MPa) 560 (3.9) 550 (3.8) 470 (3.2) 380 (2.6) 320 (2.2) Tensile, Psi (MPa) 4870 (33.5) 5000 (34.5) 5450 (37.6) 4170 (28.7) 2260 (15.6) Elongation, % Tear, Die C, Pli (kn/m) 310 (54.3) 300 (52.5) 260 (45.5) 225 (39.4) 160 (28.0) Tear, D-470, Pli (kn/m) 60 (10.5) 60 (10.5) 70 (12.3) 55 (9.6) 40 (7.0) Compression Set Method B, 22 F, % Bashore Rebound, % Specific Gravity Cured 1 C (212 F); postcured 16 C (212 F) 4. ( NCO) PPH MBCA = (133.5) 4202 X % Theory Low Durometer Formulations with Vibrathane 8070 Copyright 2007 Chemtura Corporation. All rights reserved Page 4

5 The hardness of low NCO prepolymers, including Vibrathane 8070, cured with diol or triol/mbca blends exhibit strong sensitivity to both mix and curing temperatures. Laboratory experience has taught that meticulous care must be taken during processing to achieve consistent durometer with such curative blends. When it is necessary to achieve lower hardness with Vibrathane 8070/MBCA cures, we recommend using a plasticizer such as Benzoflex 9-88SG 5. For further information on low durometer formulations, please contact Adiprene/Vibrathane Technical Service Trademark, Velsicol Chemical Company Copyright 2007 Chemtura Corporation. All rights reserved Page 5