A kind of material for making rigid foam plastics and its preparation method for rigid foam plastics

Abstract

The invention discloses a material used for preparing a rigid foamed plastic, and a preparation method of the rigid foamed plastic. According to the preparation method, a polyester polyol, an isocyanate, a catalyst 1, a catalyst 2, a physical foaming agent, a foam stabilizer, and a cross-linking agent are taken as raw materials; the degree of functionality of the polyester polyol is high, and ranges from 2.8 to 3.0, the viscosity of the polyester polyol at 25 DEG C ranges from 7000 to 10000mPa.S, hydroxyl value ranges from 380 to 450mgKOH / g, and acid value ranges from 0.1 to 2mgKOH / g; the foam stabilizer is a mixture of two organosilicon surfactants; organic combination of two key technologies, high efficiency emulsifying and nucleation, in rigid foamed plastic processing is realized, and the rigid foamed plastic with a compression strength and a bending strength of 500KPa or higher, and a dimension changing rate (80 DEG C, 48h) of 0.4% or lower is prepared. The rigid foamed plastic can be widely applied to the fields such as building and building material, communication and transportation, and refrigerating plants such as refrigerators, and cold storages.

Description

technical field [0001] The invention belongs to materials for making rigid foam plastics and the preparation of foam plastics. It relates to a material for manufacturing rigid foam plastics and a method for preparing rigid foam plastics. The invention uses raw materials such as high-functionality polyester polyols to prepare high-strength polyurethane foam plastics. The obtained rigid foam plastics are suitable for building materials, Transportation, refrigerators, freezers and other refrigeration devices and equipment and other fields. Background technique [0002] In the prior art, the preparation methods of polyurethane rigid foams are mainly divided into two types: polyester polyol type and polyether polyol type. The functionality of polyester polyols is generally around 2.0 to 2.4. If polyester polyols are simply used to produce polyurethane rigid foams, due to their low functionality, the degree of crosslinking inside the foam will be insufficient, which will affect ...

AI Technical Summary

Problems solved by technology

If polyester polyols are simply used to produce polyurethane rigid 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

[0003] 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 polyurethane rigid foam obtained has been improved to a certain extent, but it barely meets the strength requirements of the polyurethane rigid foam composite insulation board in the construction industry standard "JG / T 314-2012" (compressive strength ≥ 150KPa), 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 No. 200610039944.5 uses rapeseed oil to prepare a biomass-based polyol, and then mixes it with other polyether (or polyester) polyols to foam to prepare polyurethane rigid 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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