Rigid polyurethane foam plastic and preparation method thereof

Abstract

The invention provides a rigid polyurethane foam plastic, which is prepared from the following raw materials: isocyanate, high-functionality polyester polyol, a nano microsphere reinforcing agent, a foaming agent, an organic silicon foam stabilizer, a cross-linking agent, a catalyst and a compound filler. The method has the advantages of simple process, easy industrial production, no generation ofthree wastes in the whole process, meeting of environmental protection requirements, and strong practicality.

Description

technical field [0001] The invention relates to the technical field of polyurethane materials, in particular to a rigid polyurethane foam and a preparation method thereof. Background technique [0002] Polyurethane is the abbreviation of polyurethane, which is a general term for a class of polymers with repeated -NHCOO- groups on the main chain prepared by the reaction of polyols and polyisocyanates. The most important thing in polyurethane products is polyurethane foam, which has excellent physical and mechanical properties, acoustic properties, electrical properties and chemical resistance. , Variety and other adjustment formula combinations, to produce end products with various properties and uses, so it is widely used. The biggest advantages of rigid polyurethane foam are light weight, good heat insulation, sound absorption and shock resistance, high compression strength and good dimensional stability, so it is widely used in national defense, construction and transport...

AI Technical Summary

Problems solved by technology

If polyester polyols are simply used to produce rigid polyurethane foams, due to their low functionality, the degree of crosslinking inside the foam will be insufficient, which will affect the mechanical strength of the foam, and ultimately affect the dimensional stability of the foam, making it difficult to When used in the field of building insulation, it is prone to severe shrinkage, which makes the foam board easily fall off from the building bonding surface

Although the functionality of polyether polyols is relatively high (usually ≥ 4), it is simple to use polyether polyols with 4 functionalities (for example, the brand is 4110, and its functionality is 4) for foaming. The main chain structure is an ether bond, and its strong intramolecular flexibility will reduce the mechanical strength of polyurethane rigid foam made of polyether, and simply use a higher functional polyether polyol (such as the brand N-635, its functional Degree 6), on the one hand, because of its high functionality, the foaming process is difficult to control, which can easily lead to excessive foam crosslinking density; on the other hand, this type of polyether polyol has a higher hydroxyl value (usually ≥450mgKOH / g), compared with the same number of polyester polyols, the use of this type of polyether polyol will consume more isocyanate, which will not only increase the cost, but also greatly increase the content of hard segments in the foam, causing the board to become crispy and flaky. crisp

In order to solve the above problems, the existing foaming technology generally adopts the method of mixing polyether polyol and polyester polyol to increase the average functionality of the polyol mixture, and uses the ester bond inside the polyester polyol to increase the rigidity of the material. , but on the one hand, because the main chain structure of polyether polyol and polyester polyol is not consistent, the miscibility of the two is poor, and stratification often occurs after high-speed mixing and stirring, which will destroy the structure of the cell structure. Regularity, and affect the rigidity and thermal conductivity of the foam, on the other hand, this method is more cumbersome and costly

[0004] Chinese Patent Application Publication No. CN104262596A discloses a high-functionality polyester polyol and a preparation method thereof. It adopts a high-functionality polyester polyol and foams a rigid foam by prior art methods, although the produced The mechanical strength of the obtained rigid polyurethane foam has been improved to a certain extent, but it barely meets the strength requirements for polyurethane rigid foam composite insulation boards in the construction industry standard "JG / T314-2012" (compressive strength ≥ 150KPa), while In practical applications, most industries have higher requirements for the mechanical strength and dimensional stability of foamed plastics (general requirements ≥ 200KPa), which also makes the above-mentioned foamed plastics have great limitations in practical applications.

Chinese Patent Application No. 200610019610.1 provides a method for preparing high-strength polyurethane foam with polyether polyol. This method mainly increases the strength of the foam by adding inorganic materials in the formula. However, the above-mentioned inorganic materials are difficult to be uniform during the mixing process. Distributed in the polyether polyol system, cause the cell density that it forms when foaming is uneven, easy to open or even collapse, directly affect the dimensional stability of the foamed plastic product (the foamed plastic product prepared by this method, at 20 ℃, under the condition of 24 hours, the dimensional stability > 0.6% (and according to the foamed plastics prepared by the method of the present invention, it is at 80 ℃, under the condition of 48 hours, the dimensional stability < 0.5%)

Chinese patent application number 200610039944.5 uses rapeseed oil to prepare a kind of biomass-based polyol, and then mixes it with other polyether (or polyester) polyols to foam and prepare rigid polyurethane foam. Although this method has a certain effect on reducing costs, However, the mechanical strength of the foamed plastic prepared by this method is not high, and the molding density is 37.6kg / m 3 The compressive strength only reaches 203KPa, which limits the application field of foamed plastics; secondly, the preparation of bio-based polyols with rapeseed oil is too complicated and the product quality is not stable.

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