Polywin developed one kind of TDI/ester, Madisonol® HS series is a special ester-based prepolymer that cast with MOCA, which is no different from conventional TDI/ester in the pouring process. In terms of physical properties, it is equivalent to or even exceeds MDI/ester products. As a result, HS is a high-quality prepolymer that is easy to process and has high quality.

The background of HS emerge in this market

u Conventional TDI polyester prepolymer

For cast polyurethane, the mining and steel industries are important end markets. In the Chinese market, TDI/ester prepolymers are mainly supplied to these two industries. TDI-prepolymer has low price, excellent conventional physical properties, and simple pouring process. However, TDI polyester products are not resistant to water, low rebound, large endogenous heat, rapid strength decline at high temperatures, poor low-temperature resistance, general fatigue resistance, high permanent deformation and so on. So TDI-polyester has made a deep low-end brand on the industry.

For the gallop screen, the fatigue resistance of TDI polyester is only 10W times, the board surface is easy to break, and the service life is less than 1 month, which cannot meet the application. For the dewatering screen, TDI/ester has poor rebound and is not resistant to water, and the slag is easy to get stuck in the cracks, so downstream manufacturers are reluctant to use it. For large-hole screens, due to the poor energy absorption of TDI/ester, the wear resistance is not as good as that of MDI/ester sieve plates. For high-speed belts, TDI/ester is not as abrasion resistant and impact resistant as MDI polyester blades. For the increasing speed of steel mills, the TDI/ester type roller has poor dynamic performance and is prone to bulging. Especially for pinch rolls, TDI polyester rollers have been fully used.

Therefore, TDI/ester is no longer competent in many industries, so it has formed a trend in the industry to replace TDI/ester prepolymers with MDI/ester.

u Hard-to-Use MDI/ester

Compared with TDI/ester polyurethane, MDI/ester polyurethane has the following advantages: High rebound, Better fatigue life, Low pressure change, Slightly better resistance to low temperatures, Slightly lower pressure change, workable in cold water, but TDI/ester without.

For two-component MDI prepolymers

- Higher price

- The viscosity is slightly high, which is not conducive to pouring complex products

- Strong heat buildup, easy to lack of pouring time for large products (the larger the product, the shorter the gel)

- The demoulding time is long, generally 1.5-2 hours, occupying the mold and production tooling

- The BDO ratio is low, and the actual chain expansion coefficient is easy to fluctuate

- BDO is easy to absorb water, resulting in product defects

For three-component MDI/ester system:

- Large investment in equipment

- The equipment is complex and requires more human investment

- Prepolymers are high in NCO, easy to crust, and easy to deteriorate in winter

- Sensitive to moisture, raw materials need strict nitrogen protection

- High exothermic reaction, products are prone to spots

- Large shrinkage

- The viscosity in the early stage is very low, and it is easy to leak material for molds that are not well sealed

Balanced solution - Madisonol® HS series

In response to above those background, Polywin has developed a distinctive HS series, HS cast with MOCA, which is no different from conventional TDI/ester in terms of pouring process. In terms of physical properties, it is equivalent to or even exceeds MDI-polyester products. As a result, HS is a high-quality prepolymer that is easy to process and has high quality. HS has the following features:

- MOCA pouring, no need for customers to change equipment;

- Prepolymers have a lower viscosity than traditional TDI-ester prepolymer, have a long gel time, and are very easy to pour;

- The product has a short demoulding time and high initial strength, which can be processed quickly;

- The product has high resilience, fatigue resistance, low pressure change, and has the same feel as MDI/ester;

- The product has good dynamic performance and high retention rate of physical properties at high temperature, which is better than TDI/ester and MDI/ester products;

- Since the chain extender is MOCA, its water resistance is slightly lower than that of MDI/ester products;

The following table shows the comparison of specific data: