PT7660 & PT7665 Shore D-60 Hard Urethane Elastomers
DESCRIPTION
The
two Shore D-60 urethane systems described here are exceptionally tough,
hard elastomers that have cured characteristics which make them well
suited for some very demanding industrial uses. Both of these systems
have very high tensile and tear strengths and excellent elongation, so
tooling or parts made with these materials are very durable. They have
very good resistance to abrasion, so they are ideal for the production
of foundry tools and patterns. These materials work hard and solve
problems!
PT7660 is an amber system with a lower viscosity and a fast cure time at
room temperature. The almost 30 minute working time combined with its
low mixed viscosity allows PT7660 to be used in both open casts and
closed molds. Its faster curing time allows quicker production of
multiple-piece patterns and smaller castings.
PT7665 is a tan colored system with a longer pot life and slower cure
and is ideal for larger castings, which will exhibit very low cured
shrinkage. PT7665 can be used to produce solid mass cast patterns,
saving time over surface casting, that is necessary with other, faster
curing systems to prevent excessive shrinkage. PT7665’s outstanding
abrasion resistance makes it perfect for demanding foundry patterns. Its
extreme toughness allows it to produce urethane tooling not possible
with other materials of this hardness. It has given many years of
excellent service in the most difficult tooling situations.
PT7660 and PT7665 can be considered very low hazard potential products,
as they do not contain any toxic or regulated raw materials in their
makeup. They do not contain methylene dianiline (MDA), or other
potentially harmful aniline derivatives, nor do they contain MBOCA or
TDI, and they do not invclude any hazardous or potentially regulated
diluents.
PRODUCT SPECIFICATIONS
| Shore D-60 System | Shore D-60 System | ||||
| PT7660 A | PT7660 B | PT7665 A | PT7665 B | ASTM Method | |
| Color | Amber | Amber | Amber | Tan | Visual |
| Viscosity | 2,800 cps | 180 cps | 6,000 cps | Thin Paste | D23932 |
| Specific Gravity, gms./cc | 1.03 | 1.12 | 1.08 | 1.11 | D1475 |
| Mix Ratio, by Weight | 100 : 44 | 100 : 60 | PTM&W | ||
| Pot Life, 4 fl oz Mass @ 77°F | 26 min. | 112 min. | D2471 |
HANDLING & CURING
Generally, with polyurethane elastomers, full properties are developed
in 7 days at room temperature (75°F). Temperatures below 75°F will
lengthen the cure time, and if the ambient temperature is below 60°F,
additional heat may be necessary for proper cure. Elevated temperatures
will accelerate the cure of urethanes, but care must be taken if a
higher temperature is used to cure the material. Generally, the higher
the curing temperature, the greater the final cured shrinkage. When heat
curing for more rapid processing, to best control shrinkage, the
casting should be allowed to set for 12 to 18 hours at room temperature
before an oven post cure. A typical accelerated curing cycle, therefore,
would be: Allow to gel on the pattern for 12 to 18 hours at room
temperature (70°F to 80°F), then post cure for a minimum of 8 hours at
150°F to 165°F and allow to cool before demolding.
PACKAGING WEIGHTS
| Quart Kit | Gallon Kit | Pail Kit | |
| PT7660 A | 2 lb. | 8 lb. | 40 lb. |
| PT7660 B | .9 lb. | 3.75 lb. | 17.75 lb. |
| Kit | 2.9 lb. | 11.75 lb. | 57.75 lb. |
| PT7665 A | 8 lb. | 40 lb. | |
| PT7665 B | 4.9 lb. | 24 lb. | |
| Kit | 12.9 lb. | 64 lb. |
Inasmuch
as PTM&W Industries, Inc. has no control over the use to which
others may put material, it does not guarantee that the same results as
those described herein will be obtained. The above data was obtained
under laboratory conditions, and to the best of our knowledge is
accurate. This information is presented in good faith to assist the
user in determining whether our products are suitable for his
application. No warranty or representation, however is intended or
made, nor is protection from any law or patent to be inferred, and all
patent rights are reserved. Before using, user shall determine the
suitability of the product for his intended use, and user assumes all
risk and liability whatsoever in connection therewith. In no event with
PTM&W Industries, Inc. be liable for incidental or consequential
damages. Buyer’s sole and exclusive remedy in such instances shall be
limited to replacement of the purchase price.
TYPICAL MECHANICAL PROPERTIES
| PT7660 A/B | PT7665 A/B | ASTM Method | |
| Mix Ratio, by Weight | 100 : 44 | 100 : 60 | PTM&W |
| Color | Amber | Tan | Visual |
| Mixed Viscosity, @77°F, centipoise | 2600 cps | 5000 cps | D2393 |
| Working Time, 4 fl. oz. Mass @ 77°F | 26 min. | 112 min. | D2471 |
| Cured Hardness, Shore D | 60 Shore D ± 5 | 60 Shore D ± 5 | D2240 |
| Shrinkage, in/in, mold #1, Vol: .053 Gal mold #3, Vol: 1.23 Gal | 0.001 in/in — | Nil 0.008 | D2566 |
| Specific Gravity, grams, cc | 1.06 | 1.09 | D1475 |
| Density, lb./cu in, | 0.0383 | 0.0396 | D792 |
| Specific Volume, cu. in./lb. | 26.1 | 25.3 | D792 |
| Tensile Strength, psi | 6014 psi | 5005 psi | D638 |
| Elongation at Break, % | 646 % | 554 % | D638 |
| Tensile Modulus @ 100% Elongation | 1896 psi | 1765 psi | D412 |
| Tensile Modulus @ 200% Elongation | 2457 psi | 2363 psi | D412 |
| Tensile Modulus @ 400% Elongation | 4071 psi | 3850 psi | D412 |
| Tear Strength, Die C, pli | 565 pli | 661 pli | D412 |
| Compression Set, Method B | 88 % | 56 % | D395 |
| Bashore Rebound | 48 % | 53 % | D2632 |
| Taber Abrasion, H18 Wheel, 1000 grams, 1000 cycles, mg loss | 13 milligrams | 19.1 milligrams | D1044 |
SAFETY & HANDLING
PTM&W epoxy products are made from raw materials carefully chosen to minimize or even eliminate toxic chemicals, and therefore offer the user high performance products with minimum hazard potential when properly used. Generally, the PTM&W epoxy resins and hardeners will present no handling problems if users exercise care to protect the skin and eyes, and if good ventilation is provided in the work areas. However, all epoxy resins and hardeners can be irritating to the skin, and prolonged contact may result in sensitization; and breathing of mist or vapors may cause allergenic respiratory reactions, especially in highly sensitive individuals. As such, avoid contact with eyes and skin, and avoid breathing vapors. Wear protective rubber apron, clothing, gloves, face shield or other items are required to prevent contact with the skin. In case of skin contact, immediately wash with soap and water, followed by a rinse of the area with vinegar, and then a further wash with soap and water. The vinegar will neutralize the hardener and lessen the chances of long term effects. Use goggles, a face shield, safety glasses or other items as required to prevent contact with the eyes. If material gets into the eyes, immediately flush with water for at least 15 minutes and call a physician. Generally, keep the work area as uncluttered and clean as possible, and clean up any minor spills immediately to prevent accidental skin contact at a later time. Keep tools clean and properly stored. Dispose of trash and empty containers properly. Do not use any of these types of products until Material Safety Data Sheets have been read and understood.