01. Introduction of PU sole solution
Polyurethane resin for sole, also known as polyurethane sole solution, is the raw material for preparing polyurethane sole. Polyurethane for soles is a microcellular elastomer between rubber and plastic. It is a microcellular elastic structure with open cells. The cell diameter is 0.01-0.1mm, and the free foaming density is 0.25-0.35. , usually 1-2 mm self-skin, with superior resilience and great energy absorption capacity.
02. PU sole solution performance advantages
The polyurethane sole has the characteristics of softness, warmth, oil resistance, flexural resistance, wear resistance, etc., which is 6 times more wear-resistant than rubber. It can be made into two-color (double-density) double-layer soles according to needs, the lower sole is a micro-foamed high wear-resistant working surface, and the inner sole is a comfortable elastic foam. Much lighter and more suitable for platform shoes that require impact resistance and perforation resistance. The mold requirements are low, and the production is convenient and investment is saved (the pressure on the mold is small when foaming, only 0.14-0.20MPa).
03. Composition of PU sole solution
PU sole solution can be divided into polyester type and polyether type.
Polyester type: the prepolymer method and semi-prepolymer method are mostly used, and it is generally composed of three components: A, B, and C. The components of each component are as follows.
Polyether type: One-step method is usually adopted. Component A is directly prepared by fully mixing polyether polyol, catalyst, foaming agent, foam equalizer, chain extender, etc. in a mixer. Component B is modified isocyanate. or liquefied MDI.
The molding method is simple, and it can produce both soles and continuous shoes. The variety and output are flexible, and it is suitable for modern industrial production.
04. PU sole solution molding process
