JPH10244538A - Regeneration of polyurethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regeneration method having no environmental problem by a simple method in the regeneration method to a polyurethane foam sheet. SOLUTION: Polyurethane foam is crushed to form urethane chips and a thermoplastic resin powder is mixed with the urethane chips to be put in a container having heating air jet orifices and heating air is jetted to melt the resin powder and, after the molten powder is pressed by an upper plate, pressure is released and the open air is sucked or jetted to cool the molten powder to obtain a block member which is, in turn, sliced into appropriate slices and the slice pieces are pressed by a hot plate of which the single surface is at least heated to melt urethane chips to form a sheet like article.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating unnecessary polyurethane foam.

[0002]

2. Description of the Related Art Unwanted materials such as polyurethane foam scraps are crushed into urethane chips, a urethane prepolymer solution is additionally mixed and charged into a container, and steam is jetted to slice a block obtained to a predetermined thickness. It is used as a cushioning material. In the above method, since a urethane prepolymer solution is used, there is a problem that it is difficult to handle due to environmental problems caused by a solvent.

In order to solve this problem, a powder having a particle size of 3 mm to 8 mm is used without using a urethane prepolymer solution.
Preheat at a temperature of 180 ° C for 5 minutes or more.
A method of regenerating a polyurethane foam by controlling the thickness of a molded product by a land spacer of a mold so as to have a temperature of 10 ° C. and a density of 0.50 to 0.85 g / cc is disclosed. (Japanese Unexamined Patent Publication No. 5-169647)

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 5-169449
In order to carry out the process industrially, it is necessary to measure the preheated urethane chips distributed over a wide range of particle size, charge them so that they do not spill into the heating mold, and smooth the surface so that they are uniform. is there. Therefore, a method for regenerating a polyurethane foam that does not use a conventional urethane prepolymer solution was developed by another simple manufacturing method.

Another object of the present invention is to develop not only a regenerated polyurethane foam having various physical properties due to a change in urethane foam density but also a composite product in which physical properties are changed by other compounds.

[0006]

According to the present invention, "a mixture of urethane chips obtained by crushing a polyurethane foam and a pulverized product of a fiber product, if necessary, is charged into a container having a jet hole for heated gas. Then, a heated gas is injected from the ejection hole to melt the resin powder, the pressure is released by the upper plate, the pressure is released, the outside air is sucked or injected, and the block obtained by cooling is sliced into an appropriate thickness, and the slice is cut. A method for regenerating a polyurethane foam in which a piece is pressed with a hot plate at least one of which is heated to melt the urethane chips to form a sheet. "
By doing so, the problem could be solved.

[0007] The thermoplastic resin powder is a material which enables slicing of urethane chips as a block. A material having a high melting point requires a higher melting temperature and requires more heat energy. Not preferred.

The temperature of the heating plate is higher than the temperature at which the urethane chips are welded, and one or both of the plates are heated at a temperature at which decomposition of the constituents does not occur so much as to form a sheet. Whether to use single-sided heating or double-sided heating depends on the intended use.

The mixing ratio of the urethane chips, the resin powder or the pulverized fiber products varies depending on the size and particle size distribution of the crushed urethane chips, and a certain range cannot be determined. The smaller the crushed particle size, the greater the minimum blending ratio of the crushed fiber product and the resin powder. A sheet having a wide range of densities can be obtained depending on the compounding ratio, slice thickness, heating and pressurizing conditions of the heating plate, and the like.

[0010]

The thermoplastic resin powder is melted by injection of a heated gas such as steam or heated air, and acts to weld the urethane chips. In addition, when fibers are blended, they also act as welding.
Therefore, the temperature of the heated gas must be at least a temperature at which the resin powder is melted. Urethane chips and fibers are welded and sliced.

When the outside air is sucked or injected after the heating and pressurization, the room temperature air of the outside air passes through the material, so that the cooling effect can be promoted, and there is an effect of improving the productivity. The welded block body can be easily sliced, and the sliced piece can be easily subjected to pressing by a heating plate in the next step.

In the blending, it is understood that the greater the blending amount of the resin powder and the fiber, the higher the rigidity of the sheet, and the greater the slice thickness and the heating temperature, pressure, and time on the heating plate, the higher the density and the rigidity of the sheet. Was. Therefore, conditions are appropriately selected according to the application.

The pulverized fiber product remains without being melted and remains stiff and increases in elasticity. In particular, the welding of the carpet backing resin to the non-heated surface may have an effect of increasing the weldability by the rivet effect. all right.

[0014]

EXAMPLE 1 10 parts of polyethylene powder was mixed with 100 parts of urethane chips obtained by crushing a piece of urethane foam having a density of 0.06, and the mixture was stirred and heated to adhere the powder to the surface of the urethane chips. 50 in a 80cm * 100cm * 120cm square container with injection holes connected to the air source
After adding Kg and injecting heated air for 4 minutes and heating to 115 ° C, the upper plate was lightly pressurized to release the pressurization, and the outside air was sucked in for 3 minutes to obtain a block body.

The average apparent density was 0.16. This was sliced to a thickness of 10 mm, and the sliced piece was pressed to a thickness of 2 mm for 2 minutes using a 220 ° C. picture heating plate to obtain an elastic sheet. It was found that when this sheet was cut into a predetermined shape and welded to the back surface of an automobile carpet during molding, a good sound insulating material was obtained.

[0016]

EXAMPLE 2 100 parts of urethane chips obtained by crushing a piece of urethane foam having a density of 0.04 were crushed with 70 parts of anti-wool of a woven fabric composed of natural fibers and synthetic fibers.
100 parts of pulverized material obtained by pulverizing felt scraps obtained by heat-treating a web consisting of 0 parts to melt polypropylene cotton;
80 cm * 100 cm * having an injection hole in which 30 parts of ethylene-vinyl acetate resin powder are mixed and agitated so that a kana body is attached to chips and crushed fibers to a heated steam source.
It was put into a 120 cm square container, heated steam was injected for 3 minutes, heated to 95 ° C., lightly pressurized with the upper platen, then depressurized, sucked in outside air for 2 minutes and cooled to obtain a block.

The density of this product was 0.14 as an average apparent density. This is sliced to a thickness of 10 mm, and the sliced piece is used as a one-sided heating plate at 220 ° C. for 2 minutes and a thickness of 3 m.
m to obtain a sheet with a non-heated surface having fine irregularities.
It was found that this sheet was welded to the back of the carpet at the time of molding, as in Example 1, to provide a carpet with excellent sound insulation. In particular, it has been found that the non-heated surface has a good welding property to the ethylene-vinyl acetate resin containing calcium carbonate, which is a car backing resin.

[0018]

The urethane chips are mixed with a thermoplastic resin powder to melt the powder, and the urethane chips are welded together to facilitate slicing as a block. It was possible to regenerate urethane sheets with high productivity using simple equipment that does not have environmental problems and is easy to handle without using. Further, a ground product of a fiber product was blended, and the urethane sheet could be regenerated into a modified urethane sheet having modified rigidity and weldability of a resin. The material is a fiber product that does not require urethane foam, and by using them, resources could be used effectively.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 04 105: 26 B29L 7:00

Claims (2)

[Claims] An urethane chip obtained by crushing a polyurethane foam mixed with a thermoplastic resin powder is charged into a container having a heating gas ejection hole, and the heating gas is ejected from the ejection hole to form a resin powder. The block obtained by melting and pressing the upper plate and then releasing the pressure and sucking or ejecting the outside air to cool and slice the block to an appropriate thickness, and pressing the sliced piece with a hot plate at least one of which is heated. A method for regenerating polyurethane foam by melting urethane chips to form a sheet. 2. A mixture of a urethane chip obtained by crushing a polyurethane foam and a thermoplastic resin powder and a crushed product of a fiber product is charged into a container having a heated gas outlet, and the heated gas is discharged from the outlet. Injecting and melting the resin powder, pressing the upper plate, releasing the pressure, releasing the outside air, or injecting or ejecting the air to cool and block the resulting block body to an appropriate thickness, and heat the sliced piece at least one of which is heated A method for regenerating polyurethane foam by pressing a plate to melt urethane chips to form a sheet.