Process for preparing rigid polyurethane foams

Abstract

The invention discloses a manufacturing method of hard polyamino foam plastic, which comprises the following steps: a) blending foamer and foaming additive through circulating transmitting pump; b) adopting polyol, water, catalyst and stabilizer to make composite polyether; c) transmitting the foamer, foaming additive and composite polyether to the static blender to mix; d) reacting composition and polyisocyanates to foam. The invention can form dense, even and seal foam hole, which reduces heat conductive coefficient and improves the insulating property of insulating layer.

Description

technical field [0001] The invention relates to the technical field of foamed plastics, in particular to a production method of rigid polyurethane foamed plastics. Background technique [0002] Rigid polyurethane foam has good thermal insulation performance and certain strength, and is often used as the insulation layer of refrigerators and freezers. The production method of preparing rigid polyurethane foam is to mix the mixture of combined polyether (including polyol, water, catalyst, stabilizer, foaming agent) and organic polyisocyanate under high pressure, and then high-pressure inject it into the middle interlayer of the refrigerator box, etc. area. After injection, the blowing agent is converted from liquid to gas under the high temperature generated by the PU reaction, and a large number of bubbles are generated, so that the polyurethane polymer forms a honeycomb foam structure and forms a foam plastic. In order to obtain rigid polyurethane foams with excellent ther...

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Problems solved by technology

[0003] In order to reduce the thermal conductivity of cyclopentane to improve its thermal insulation performance, suitable foaming additives can be used to promote the reaction of polyols and organic polyisocyanates to generate fine and uniform foams with small closed cells. Nucleating additives are added during the foaming process, such as 3M’s 6-carbon perfluoroolefin, the main component of which is perfluorohexene, with a boiling point of 20-80°C. However, the use of this additive can reduce the thermal conductivity of polyurethane foam, but The GWP of this additive is 9000, the greenhouse effect is obvious, and it cannot meet the current international environmental protection requirements, so it will gradually stop using it

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