Hard polyurethane molding foam negative pressure foaming raw material formula and hard polyurethane molding foam negative pressure foaming production method

Abstract

The invention relates to a formula of a hard polyurethane molding foam negative pressure foaming raw material, wherein the raw material is prepared by mixing polyether polyol, a polyester polyol, a foam stabilizer, a catalyst and water, and a weight ratio of the polyether polyol to the polyester polyol to the foam stabilizer to the catalyst to the water is 50-90:10-50:2-3:2-3:1-2.5. The hard polyurethane molding foam negative pressure foaming production method comprises carrying out hard polyurethane foaming under a state with a negative pressure of 0 to -0.025 MPa, wherein polyurethane foaming is performed under the negative pressure state so as to reduce polyurethane raw material requirements. In addition, a high functionality polyester polyol can be adopted as a main polyol to prepare a combination polyether so as to carry out foaming, such that a mold cavity can be filled in a short time, and the prepared foam has characteristics of thin cell, high strength and good size stability.

Description

Technical field: [0001] The invention relates to the technical field of rigid polyurethane foam manufacture, in particular to a rigid polyurethane molded foam negative pressure foaming raw material formula and a production method thereof. Background technique: [0002] Under normal circumstances, the production of rigid polyurethane molding foaming is carried out under normal pressure. When the foam is foamed in the mold cavity, as the volume gradually increases and the gas released increases, the flow of the foam in the mold cavity is affected by the internal pressure. The resistance brought by the increase of air pressure will also gradually increase, which will cause insufficient filling or uneven density distribution. The existence of pressure will have a greater impact on the quality of the finished foam. Therefore, foam products have higher requirements on the fluidity and strength of raw materials. Especially in recent years, with the expansion of market demand, highe...

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Problems solved by technology

[0003] 1. Due to the excessively fast polymerization reaction speed, the viscosity of the raw material increases too fast, the fluidity of the foam is greatly reduced, and it is easy to form surface or internal cavities when flowing in the cavity, which affects the thermal insulation and appearance of the foam;

[0004] 2. Due to the excessively fast polymerization reaction speed, the foam has begun to solidify without filling the box, and some places in the box are not filled

[0005] Therefore, the use of normal-pressure rigid polyurethane combined with polyether often brings a lot of product quality problems, which means that there are great limitations in ordinary foaming methods

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