Principle and selection of PU polyurethane release agent

Principle of PU polyurethane release agent:The bonding force between polyurethane and mold surface is generally believed to be caused by two reasons. Firstly, the surface of the mold is usually covered by a very thin or even monolayer water film, which reacts with isocyanates to produce strong adhesion. Secondly, adhesion is caused by the chemical bonds formed by the polar groups on the inner surface of the mold reacting with the polar groups of polyurethane and polyurethane. In order to make the product easy to demold, it is necessary to have a dense and smooth film on the surface of the mold. The film must not react with the raw materials, have a certain degree of adhesion to the mold, and have a certain degree of flexibility. Spray the effective demolding substance (usually an inert substance) evenly onto the mold through a medium (water), and after the medium (water) evaporates, a smooth film is formed, thus achieving the demolding effect.

Selection of PU polyurethane release agent:The main component of PU polyurethane release agent is a mixture of organic silicon and high-temperature resistant resin, which has excellent thermal and chemical stability, excellent demolding and isolation effects, does not corrode the mold, does not leave decomposition products on the mold surface, has a smooth and beautiful appearance, does not affect the adhesion and paint strength of the product, and does not pollute the mold.

Usage method of PU polyurethane release agentHeat the mold to above 50 ℃. Dilute the release agent with a solvent or solvent mixture, and evenly apply it to the mold with a brush or spray gun. After the solvent evaporates, it can be used. The frequency of use is based on the complexity of the mold and the molding material. Generally, shoe soles or elastic components are sprayed 2-3 times. For better dispersion on the surface of the mold, it is recommended to dilute with volatile petroleum ether solvent or 25-30 parts of chlorinated solvent.

What are the main technical requirements for PU polyurethane foaming process, including product thickness, dual hardness product insulation, concave blocks, test area shape, and intermediate skeleton connection of the product.