Preparation method for low-density viscoelastic polyurethane foam

Abstract

The invention relates to a preparation method for low-density viscoelastic polyurethane foam. Based on 100 parts by weight of mixed polyether, Isocyanate reaction active ingredients include (biii) 70-95 percent of propylene epoxide, ethylene oxide copolymerized polyol or a compound thereof, wherein the oxygen ethylidene unit content is not less than 70 percent by weight, (biii) 5-30 percent of propylene epoxide, epoxy ethane copolymerized polyol or a compound thereof, wherein the oxygen ethylidene unit content is 20 percent by weight at most, and (biv) 0-15 percent of propylene epoxide, propylene epoxide copolymerized polyol or a compound thereof, wherein the oxygen ethylidene unit content is 20 percent by weight at most; a reaction system does not contain any toluene diisocynate component or foaming agents except water; at least two polyether polyols are taken as major polyethers; and low-density viscoelastic polyurethane foam with low odor and excellent fatigue resistance is prepared.

Description

technical field [0001] The invention relates to a method for preparing viscoelastic polyurethane foam, in particular to a method for preparing low-density viscoelastic polyurethane foam. Background technique [0002] Viscoelastic polyurethane foam, also known as slow rebound foam, is mainly used for pillows and mattresses. The annual production of viscoelastic foam in China is about 50,000 tons, and more than 95% of them are exported to Europe and the United States. Although the current domestic demand market is small , but the potential is huge, and it is expected to continue to grow at a rate of more than 15% in the next few years. [0003] Viscoelastic foams exhibit slow recovery during compression cycles, and thus high hysteresis, and generally low ball rebound values. These properties are mostly caused by the structure of the foamed polymer itself. One method is to control the glass transition temperature of the foam near room temperature through the selection of compo...

AI Technical Summary

Problems solved by technology

However, the physical blowing agents such as HCFC-141b or dichloromethane used in this method are all non-environmental protection products, which are harmful to human body and environment.

[0012] In addition, in order to reduce the density, some manufacturers will also use a large amount of highly toxic TDI, which makes the manufacturers have to go through various cumbersome purchase and use procedures. At the same time, TDI also poses a great threat to the health of operators.

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