PTMEG Based Casting Polyurethane Prepolymer have good abrasion resistance,water resistance,germ proof,excellent mechanical properities,color regualting by adding pigment.
PTMEG Based Casting Polyurethane Prepolymer can be used to make rods, rollers, caster wheel, sealing ring,sieve palste and other polyurethance elastomers.
PTMEG Based Casting Polyurethane Prepolymer after vacuum degassing at 80-85℃, blending with melted MOCA, degassing and then casting, vulcanization molding. PTMEG TDI Polyurethane Prepolymer is apply to manual or casting machines
Product Specifications
|
BQ6595 |
Unit |
Test Data |
Testing Standard |
|
Appearance (20°C) |
Colorless transparent viscous liquid |
||
|
NCO% |
% |
6.3±0.2 |
HG/T 2409 |
|
Viscosity (80°C) |
mPa·s |
500±100 |
GB/T 12009.3 |
Storage Conditions
PTMEG Based Casting Polyurethane Prepolymer should be stored in a cool, dry place, avoiding moisture and high temperatures. The shelf life of unopened prepolymer is twelve months.
Casting Process
|
Preheat temperature before use/℃ |
70±5 |
|
Preheat time before use/h |
4~6 |
|
Chain extender type |
MOCA |
|
Recommended R value ratio (isocyanate/chain extender) |
1.05~1.1 |
|
Mixing temperature of prepolymer/℃ |
75~85 |
|
Mixing temperature of chain extender/℃ |
110 |
|
Prepolymer to chain extender ratio/ per 100 parts of prepolymer |
18.5~18.8 |
|
Mold temperature during casting/℃ |
100 |
|
Oven temperature during casting/℃ |
100 |
|
Gel time/min |
5~6 |
|
Demold time/min |
20~30 |
|
Post-curing time (100℃)/h |
12~16 |
The above test results are based on samples PTMEG TDI Polyurethane Prepolymer molded in a rectangular flat mold weighing 100g.
Demold time depends on the size and shape of the casting. If the product is larger or the mold shape is complex, the curing time should be appropriately extended.
Finished Product Properties
|
Item |
Unit |
Standard |
BQ6595/MOCA |
|
Appearance of finished product (25℃) |
Light yellow elastomer |
||
|
Finished product hardness |
Shore A |
GB/T 531.1-2008 |
95±2 (45D±3) |
|
Finished product density |
g/cm³(25℃) |
GB/T 533-2008 |
1.126 |
|
100% Modulus stress |
MPa |
GB/T 528-2009 |
13 |
|
300% Modulus stress |
MPa |
GB/T 528-2009 |
28 |
|
Tensile strength at break |
MPa |
GB/T 528-2009 |
52 |
|
Elongation at break |
% |
GB/T 528-2009 |
380 |
|
Right angle tear strength |
kN/m |
GB/T 529-2008 |
113 |
|
DIN abrasion |
mm³ |
GB/T 9867-2008 |
53 |
|
Rebound resilience |
% |
GB/T 1681-2009 |
42 |
Processing Procedure
1.Preheat the PTMEG Based Casting Polyurethane Prepolymer to 70~75℃ for 4~6 hours until completely melted. Take a measured amount of PTMEG Based Casting Polyurethane Prepolymer and heat to 85~90℃, and degas under a vacuum of -0.1MPa until all bubbles are eliminated.
2.Measure a quantity of MOCA and heat until melted (around 110℃), and set aside for later use.
3.Control the temperature of the degassed PTMEG Based Casting Polyurethane Prepolymer between 75～85℃, add the melted MOCA, using a ratio of 100 parts prepolymer to 18.5~18.8 parts MOCA, and mix evenly. Pay attention to the working time; pigments can be added with the chain extender.
4.Secondary vacuum defoaming can be performed within the working time, controlling the defoaming time to less than 1 minute until no obvious bubbles are present.
5.Pour the mixed material into a mold coated with a polyurethane-specific release agent and preheated to the correct temperature, with the mold temperature controlled at 100℃. Be careful to avoid trapping too many bubbles when pouring, and break any bubbles that rise to the surface with a flame.For products that require pressure molding, control the gel point before the surface becomes sticky but is not yet completely hardened.
6.The demold time is 20~30 minutes. Generally, the larger the product, the longer the demold time, so please extend the demold time appropriately.
7.After demolding, the product should be placed in a 100℃ oven to continue post-curing for 12~16 hours until the physical properties fully meet the requirements.
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