MOCA cured high performance polyester prepolymer

Madisonol®HS90 is a special TDI-polyester polymer. When using MOCA as curative, HS90 has the same casting process as TDI-polyester based material, but has similar physical properties with MDI-polyester products. Thus HS90 is a prepolymer with good processing and high-quality.

Polyurethane Industry Pain Point

Low-end TDI prepolymers

For cast polyurethane, the mining and steel industries are important end markets.TDI-polyester prepolymers in the Chinese market are also the main supply of these two industries. TDI-polyester  product have the advantages of low price, excellent conventional physical properties and simple casting process. However, TDI-polyester products have some disadvantages, such as poor water-resistant, low rebound, large endogenous heat, fast strength decline at high temperature, poor low temperature resistance, weak fatigue resistance, high permanent deformation and so on. So TDI-polyester prepolymers are often being labeled as low-end products.

For the tension screen, the fatigue resistance of TDI-polyester product is only 100,000 times. The plate surface is easy to fracture and the service life is less than 1 month which can not meet the application requirement. For dehydration screen, TDI-polyester product has poor rebound and weak water resistance. Slag is easily trapped in the cracks, so the downstream manufacturers are unwilling to use. For large-hole screen, TDI-polyester  product has poor energy absorption and poor wear resistance compared to MDI-polyester product. For high-speed belt, TDI-polyester  product's abrasion resistance and impact resistance is weaker than MDI-polyester scraper. For the increasing speed of iron and steel plant, TDI-polyester product's poor dynamic performance makes it easy to produce bulges.Especially for the pinch roller, TDI-polyester rubber roller is no longer in use at all. So TDI-polyester prepolymer in many industries have been unable to do. MDI-polyester prepolymer has formed a trend to replace TDI polyester prepolymers.

Addvantages of using MDI polyester

 Compared to TDI-polyester polyurethane, MDI-polyester polyurethane has the following advantages:

--High resilience

--Better fatigue life

--Lower pressure

--Slightly better low temperature resistance

--Slightly lower compression set

--Can work in cold water, but TDI-polyester prepolymer can not.

Difficulties in using MDI polyester

At the same time, MDI polyester prepolymer also has its pain points.

For two-component MDI prepolymer:

-Cost slightly higher

--Viscosity slightly larger, not conducive to casting complex products

--Large heat storage; casting time is insufficient for large products(the bigger the product, the shorter the gel)

--Long demoulding time(generally to 1.5-2 hours), occupy mold and production tooling

--BDO ratio is low; the actual chain expansion coefficient is easy to fluctuate

--BDO easy to absorb water, causing defects in the product

For the casting of three-component MDI-polyester:

--Equipment investment is large, the cheapest is more than 30W

--Equipment is complex, requires the operator's high-quality

--High NCO content, easy to crust, easy to deteriorate in winter

--Sensitive to water, the raw material needs strict nitrogen protection

--High exothermic reaction, the product is easy to appear spots

--Shrinkage rate is large

--Early viscosity is very low, easy to leak material for untight mold

Perfect Solution ---Madisonol® HS90 Prepolymer

For the polyurathane industry's pain point, Polywin developed a characteristic prepolymer named Madisonol® HS90. HS90 uses MOCA as curative and its casting process is not different from TDI-polyester prepolymer and its physical properties is equivalent to MDI-polyester products or even more. Thus HS90 is a prepolymer with good processing and high-quality. HS90 has the following features:

-- MOCA as curative , no equipment replacement

--lower viscosity than the traditional TDI-polyester prepolymer

--long gel time, very easy to casting

--short demoulding time, high initial strength, fast processing

--high resilience, excellent fatigue resistance, low compression set, with the same feel as MDI-polyester

--excellent dynamic performance, higher physical property retention rate at high temperature than TDI polyester and MDI-polyester products

--due to chain extender MOCA, its water resistance is slightly better than MDI-polyester products

VS901 is the TDI-polyester prepolymer, S1650 is the MDI-polyester three-component casting system, SM903 is the MDI-polyester two-component prepolymer. MSR is a MOCA-cured MDI-polyester prepolymer. Its physical properties is similar to HS90, but MSR's viscosity is higher and gel is faster. So it's difficult to cast large products. And the price is relatively expensive. The two reasons limit its use.