Wanhua Chemical high-resilience polyether series has been commercialized for more than a year since the production started in September 2016. The products have been widely recognized and highly praised by customers for its high activity, low odor, low VOC, stable and good quality.
With the improving standard for air quality of automotive interiors and the increasing demands of people on the comfortability of car seats, there are ever growing requirements on inherent quality of polyether products for the application of polyurethane.
To better meet customer demands, Wanhua Chemical has strived to make technological breakthroughs to improve the inherent quality and application performance of products. According to researches, the degree of functionality of polyether directly influences the performance of foam products. As there are side reactions during the synthetic process, in which terminal hydroxyl groups are replaced by unsaturated bonds and carboxyl groups, causing a reduction in the content of terminal hydroxyl groups, the measured degree of functionality is generally lower than the theoretical value. The more violent the side reactions are, the bigger the difference between the measured value and thoretical value is.
Generally, the inhibition of side reactions and improvement of the measured degree of functionality can be achieved by optimization of raw materials, CAT and production process control.
☛ Glycerol
High-quality glycerol is necessary for polyether production. In addition to purity, saponification equivalent shall be of great concern. A higher saponification value means higher content of fatty acid, esters and alcohols in the raw materials, leading to side reactions during the polymerization process with PO.
☛ Moisture
At present, the moisture of such main raw materials as glycerol, PO and EO used for polyether production is generally controlled at a low level. However, in case of preparation of potassium alkoxide solution by reaction between glycerol and KOH, the moisture produced shall be completely removed to enhance the degree of functionality of the final product. Generally the moisture shall be controlled below 500ppm.
☛ EO
In view of typically high molecular weight of EO terminated polyether and relatively low concentration of CAT during polymerization, the flow, temperature, stirring speed or circulation volume for polymerization shall be controlled to reduce self-polymerization of EO and enhance effective capping rate.
☛ CAT
Generally KOH is used as the catalyst for the synthesis of polyether. It has high reactivity, however which could reduce along a curve as the PO/EO polymerization goes on and the molecular weight grows. Delivery of desired products may be guaranteed by adding CAT in a balanced manner and controlling the PO/EO flow curve to improve the polymerization conversion rate.
☛ Temperature
In the synthetic process of polyether, there is strict requirement on the selection of temperature for PO/EO polymerization. Excessively high or low temperature would have significant impact on side reactions. Therefore, a reasonable standard for temperature control shall be determined and the system shall be kept stable.
Wanhua Chemical has optimized the production process by taking such measures as control of quality of raw materials, deep removal of moisture in potassium alkoxides and optimization of polymerization speed, to minimize side reactions, enhance conversion rate of polymeric monomer, and accordingly, effectively enhance the degree of functionality of polyether products.
For example, Wanhua Chemical WANOL® F3135/F3128 features a measured degree of functionality more than 10% higher than that of other commercially available products of the same type. Wanhua Chemical also produces high-resilience POP with the said products. The two are used collaboratively for production of composite material for car seats and shoe soles as well as in other industries. They exhibit unique and excellent performance in improving the mechanical property, dimensional stability, fineness of foam cell, and comfortability.
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