RU1799878C - Method of preparing elastic foam materials - Google Patents

Abstract

Use: for the manufacture of molded cushioning pads and products. SUMMARY OF THE INVENTION: latex copolymer of butadiene and methyl methacrylate in an amount of May 10-60. by spraying applied on May 100. including crushed polyurethane foam waste, pollinated waste is mixed and placed in a mold. Latex may additionally contain in its composition as a hardener a mixture of ethylene glycol Zfirs tri- and tetramethylolmelamines in an amount of May 1 - 5. hours on May 100. including crushed waste polyurethane foam. The molding is carried out at 60 - 80 ° C for 2 hours. The finished material has a hardness index of 4.5 - 6.6, residual deformation of 4.4 - 10.0%. 2 tab.

Description

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WITH

The invention relates to the chemistry of polymers, and more specifically, to a method for producing elastic foams.

The aim of the present invention is to improve the physicomechanical properties of foams (i.e., control stiffness and increase residual deformation), lower the molding temperature and simplify the technology for producing foams (by eliminating the steps of drying and squeezing the moldable mass to remove excess latex).

The goal is achieved in that as latex use a 20% latex copolymer of butadiene and methyl methacrylate in the amount of May 10-60. hours on May 100. including crushed polyurethane foam waste and molding is carried out at a temperature of 60 - 80 ° C for 2 hours.

An additional objective of the present invention is the production of elastic foams with a high stiffness index, which strengthens the essence of the claimed solution, since it helps to expand the range of physicomechanical properties of the resulting foams.

This goal is achieved in that a mixture of ethylene glycol esters of tri- and tetramethylolmelamines (Glycosin) in an amount of May 1-5 is used as a hardener. hours on May 100. including crushed waste polyurethane foam.

A comparative analysis of the claimed solution with the prototype shows that the claimed method differs from the known one in that the elastic foams are molded using a new liquid polymer binder, and

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namely: 20% aqueous latex of butadiene and methyl methacrylate with or without hardener glycosine. Thus, the claimed method meets the criterion of novelty.

An analysis of the literature shows that there are known methods for producing flexible foams from PUF waste by molding using liquid polymer or oligomeric binders, including latexes. However, unlike the indicated methods, in the claimed solution, the use of aqueous latex of a copolymer of butadiene and methyl methacrylate with or without hardener glycosine allows one to obtain foams with improved physicomechanical properties, i.e. materials with controlled stiffness and increased residual deformation It also reduces the molding temperature and simplifies the process of producing foams by eliminating the stages of drying and squeezing the moldable mass to remove excess latex mass. The foregoing allows us to conclude that the claimed decision meets the criterion of significant differences.

The amounts of the taken components should correspond to the declared one, since the latex content of the butadiene copolymer and methyl methacrylate (latex grade DMMA, GOST 13522-72) is lower than May 10. Particularly, it leads to incomplete wetting of crushed PPU waste, which makes it difficult to form a single cellular structure in the molded foams, and the residual deformation of the resulting elastic foams excessively increases (beyond the limits allowed by GOST 19918.3-79). The content of latex DMMA above May 60. hours does not lead to further improvement of the physico-mechanical properties of the resulting foams. An excess increase in the content of DMMA latex (for example, up to May 70 h) leads to an excess increase in stiffness and, in addition, leads to an increase in the time for molding foams due to the presence of more water that must be removed from the volume of the foam.

An increase in the content of glycosine hardener (GOST 10457-73) above the stated limits leads to an excess increase in the stiffness of the molded foams and, therefore, is impractical.

Lowering the molding temperature below 60 ° C leads to undercure

composition (for a given molding time), causing an excessive increase in residual deformation. An increase in the molding temperature above 80 ° C does not give a further improvement in the properties of the foams, since this leads to decomposition of the DMMA latex and, therefore, makes it difficult to form a single cellular structure of the molding materials.

Shortening the molding time below the claimed leads to a non-curing of the composition, to incomplete removal of water from the internal volume of the foamable material, and, therefore, causes

5 deterioration of its physical and mechanical properties. The increase in molding time above. Beyond the stated limits is impractical, since it does not lead to further improvement of physicomechanical properties

0 foam.

The application of DMMA latex to PUF waste is carried out by spraying, which provides a more uniform and better wetting of the surface of crushed PUF waste.

Example. The south of the liquid polymer binder — 20% aqueous latex of a butadiene-methyl methacrylate copolymer (DMMA latex) was sprayed on 100 May. hours

0 PPU waste. The finished pollinated PPU waste is mixed and placed in a mold with a size of 20 x 10 x 10 cm, the crumbs are pressed with the help of the top cover, the resulting overpressure

5 provides a fixation of the geometric dimensions of the molded foam and contributes to better adhesion of crumbs. The mold is placed in a heating zone. The foam is molded at a temperature of 60 ° C for 2 hours. Then the mold is removed from the heating zone, cooled and the finished material is removed from the mold. The obtained elastic foam has a stiffness index of 4.5 and a residual deformation of 5%.

In the table. Table 1 shows examples No. 1-20, corresponding to different compositions of molded elastic foams and the conditions for their preparation, and in Table. 2 are given

0 their physical and mechanical properties.

From the above data it is seen that in the claimed invention, in contrast to the prototype, the residual deformation is increased and the stiffness of the formed foam materials 5 is controlled. Reducing the molding temperature and simplifying the process of producing foams by eliminating the stages of drying and pressing the moldable mass to remove excess latex leads to energy savings and increase

the productivity of the process of forming flexible foams from crushed PPU waste. In addition, the use of production waste instead of scarce raw materials makes the material cheaper. Disposing of PUF waste in this way also helps to solve the problem of creating a waste-free production of polyurethanes, including polyurethane foams.

The proposed method was tested for producing elastic foams from PPU waste at one of the furniture factories in Chisinau.

Claims (2)

1. Method for producing elastic foams by impregnating crushed waste of polyurethane foam with latex sinteTable 1 The composition of elastic foams based on crushed PPU waste and conditions for their molding rubber with subsequent molding of the elastic foam under hot curing conditions, characterized in that, in order to improve the physicomechanical properties of the foam materials, lower the molding temperature and simplify the production technology, 20% butadiene copolymer latex is used as latex and methyl methacrylate in the amount of 10 - 60 may. h, on May 100. including crushed waste polyurethane foam and molding is carried out at 60 - 80 ° C for 2 hours 2. The method of pop. 1, distinct by using a mixture of ethylene glycol esters of tri- and tetramethylolmelamines in an amount of May 1-5 as hardeners. hours on May 100. including crushed waste polyurethane foam. table 2 Physico-mechanical properties of elastic foams based on crushed PPU waste