JPH0687170A - Production of reclaimed polyurethane foam molded product - Google Patents

Abstract

(57) [Abstract] [Purpose] There is no risk of toxicity or environmental pollution in the manufacturing method of polyurethane foam remolded products in which a binder is attached to chips of waste polyurethane foam, and this is cured and molded in a molding mold. Provide a method of using a binder that does not limit the pot life. [Structure] A binder made of an aqueous resin emulsion is uniformly adhered to a waste material polyurethane foam chip, and after filling a molding mold, pressurized dry hot air is blown into the mold to dry and cure the aqueous resin emulsion. As a result, a cured product in a dry state is obtained. Aqueous resin emulsions include polyurethane emulsions, polyacrylic ester emulsions, polyvinyl acetate emulsions, poly (ethylene / vinyl acetate)
Copolymer emulsions, poly (styrene / butadiene)
Copolymer emulsions and the like can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a recycled polyurethane foam article by curing and molding waste polyurethane foam pulverized into chips into a binder.

[0002]

2. Description of the Related Art Polyurethane foam is a material widely used as a cushion material, a heat insulating material, a soundproof material, and the like. These shape-shaped products, which are continuously mass-produced, are manufactured by cutting and molding polyurethane foam according to the usage site. Recycled waste polyurethane foam commonly called "Mimi" discharged at this time is recycled. Various usage methods have been proposed.

As one of them, a method has been developed in which a waste material polyurethane foam crushed into chips is molded using a binder. This method comprises the following steps.

(A) Pulverizing treatment step: Amorphous waste polyurethane foam is pulverized into chips of arbitrary size.

(B) Binder attaching step: The binder is uniformly attached to the waste polyurethane foam crushed into chips. As the binder, solvent-type polyurethane or two-component solventless polyurethane is used. These binders are mainly composed of a high molecular weight polymer containing an active isocyanate. Since the high molecular weight polymer has a high viscosity, it is diluted with an organic solvent in the solvent type polyurethane. As the organic solvent, a halogenated solvent such as methylene chloride is used exclusively because it satisfies the requirements of volatility and nonflammability. The two-component solventless polyurethane is of a two-component type using an amine curing agent or the like.

(C) Mold filling step: Polyurethane foam chips to which a binder is attached are filled in a molding mold. At this time, chips are weighed in order to control the foam density of the obtained cured molded product. Further, the chips are uniformly filled so that there is no uneven filling.

(D) Press-cure process: By blowing pressurized steam into the chips compressed and filled in the molding mold, reaction water and reaction heat are applied to cause the binder to react and cure.

(E) Curing Molded Product Drying Step Since the cured molded product taken out from the molding mold is wet with water vapor, it is dried. Usually, it is dried in a drying oven at 90 ° C. for about 3 to 6 hours, or is dried in the sun for about 1 week to obtain a polyurethane foam recycled molded product.

[0009]

The following problems have been pointed out in the conventional methods for producing recycled polyurethane foam molded articles as described above.

1) The active isocyanate compound used as the main component of the reaction-curable binder is toxic and therefore dangerous to work, and there is a problem of environmental pollution due to an organic halogenated solvent used as a diluent solvent for the binder. .

2) The pot life of the binder containing the curing agent is influenced by the temperature and humidity of the working environment and is restricted, which lowers the working efficiency.

3) Water vapor blown into the molding mold is used as a reaction water source and a reaction heat source to react and cure the binder, so that the cured molded product is taken out of the mold in a wet state, and as a result, a drying step of the cured molded product is essential. And reduce work efficiency.

Therefore, the present invention has been made for the purpose of providing a new and improved method for producing a remanufactured molded article of polyurethane foam which can solve the problems in the conventional methods such as 1) to 3) described above. It is a thing.

[0014]

The inventors of the present invention have conducted various studies to achieve the above-mentioned object, and as a result, by using an aqueous resin emulsion as a binder,
The present invention has been completed by finding that the problems in the conventional method using a reaction-curable binder containing an active isocyanate as a main component can be solved.

That is, in the method for producing a polyurethane foam remolded product according to the present invention, a binder made of an aqueous resin emulsion is uniformly adhered to a waste material polyurethane foam pulverized into chips, which is then filled in a molding mold, The aqueous resin emulsion is dried and cured by blowing pressurized dry hot air into the mold, and the dried and cured molded product is taken out from the mold.

The method of the present invention will be described below in order of steps in comparison with the conventional method. (A) Pulverizing process: The pulverizing process can be performed in the same manner as the pulverizing process in the conventional method, and the waste polyurethane foam is pulverized into a desired size according to the purpose.

(B) Binder attaching step: The binder is uniformly attached to the waste polyurethane foam crushed into chips. For the adhesion treatment, a method of spraying a binder while stirring the foam chips can be preferably used.

In the present invention, an aqueous resin emulsion is used as the binder. The aqueous resin emulsion is cured by removing water as a solvent to obtain a cured molded article having desired physical properties. That is, since the curing is not performed by a chemical reaction, there is an advantage that there is no restriction on the pot life that accompanies the progress of the reaction unlike the conventionally used reaction-curable binder.

Aqueous resin emulsions that can be preferably used as the binder in the present invention include polyurethane emulsions, polyacrylic ester emulsions, polyvinyl acetate emulsions, poly (ethylene / vinyl acetate) copolymer emulsions, and poly (styrene / butadiene) copolymer emulsions. And the like. One of these may be used alone, or two or more thereof may be mixed and used.
Further, modified resin emulsions obtained by modifying these resins can also be used. As the modified resin, various functional groups at the molecular terminals of the above resin, for example, a carboxy group, an amino group,
Acrylic, styrene, butadiene, ethylene, propylene, vinyl, etc., all of which are modified to allow polycondensation reaction by adding allyl group, silanol group, sulfone group, etc. Examples thereof include those copolymerized in an arbitrary quantitative ratio. Among the above-mentioned aqueous resin emulsions, polyurethane emulsions having a structure similar to the material of the polyurethane foam chip can be particularly preferably selected as the binder.

The adhered amount of the binder can be adjusted by the same standard as in the past. That is, the weight of the resin component contained in the binder is adjusted to be in the range of 3 to 10% with respect to the weight of the foam chips.

Since the amount of binder required for uniform attachment varies with the shape change of the foam chip, the shape of the foam chip is controlled by the bulk specific gravity, and the binder amount is in the range of 1 to 2% with respect to the apparent volume of the foam chip. Adjust so that

The amount of binder used and the resin component concentration of the binder are determined by the following equations. Amount of binder used X (g) = A ÷ B × D Resin content concentration of binder F (%) = [(A × C) / X]
× 100 where A = foam tip weight (Kg) B = foam tip bulk specific gravity (weight ÷ apparent specific gravity) C = above adjustment standard D = above adjustment standard

For example, when 1% of foam chip having a bulk specific gravity of 0.04 is used as the above adjustment standard of 5% and the above adjustment standard of 1%, the following calculation can be performed. Amount of binder used = 1 ÷ 0.04 × 0.01 = 0.25
Kg binder resin content concentration = (1 × 0.05) ÷ 0.25 ×
100 = 20%

(C) Mold filling step: The foam chips to which the binder is attached are filled in the molding mold. As described above, since the aqueous resin emulsion as the binder is cured by removing the water serving as the solvent, it is necessary to take care not to dry the foam chips to which the binder is attached during the filling operation.
It should be noted that, by attaching a release agent to the inner wall of the mold in advance before filling, the cured molded product can be taken out of the mold easily and efficiently.

(D) Pressure-hardening step: By blowing pressurized dry hot air into the foam chips filled and compressed in the molding mold, the water in the aqueous resin emulsion, which is the binder, is efficiently vaporized and quickly. Can be cured. As a result, the time required for curing can be approximated to that of the conventional reaction-curable binder. According to the present invention, unlike the conventional method, steam is not blown in but dry hot air is blown in, so that the cured molded product taken out from the molding mold can be obtained in a dry state. Therefore, the step of drying the cured molded article, which is required in the conventional method, is not necessary.

As described above, in the present invention, various advantages can be obtained by using an aqueous resin emulsion as a binder in place of the reaction-curable binder used in the conventional method. In some cases, the water resistance of the resulting cured molded article is not always sufficient. Particularly when it is desired to obtain a cured molded article having high water resistance, it is preferable to add a water resistance improver to the aqueous resin emulsion. As the water resistance improver, an aqueous solution or an aqueous dispersion of a reaction curable polymer such as polyepoxy resins, polyethyleneimine compounds, melamine resins, glyoxal resins, polyoxazoline resins and the like can be used. In addition to these, polyamines that are effective for certain urethane-based resin emulsions, various alkoxysilane compounds known as silane coupling agents, and blocked polyisocyanate compounds and the like are used as an aqueous resin emulsion. Can be added in.

[0027]

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples. Example 1 Aqueous polyurethane emulsion (Brand name "Izelax S-1040", Hodogaya Chemical Co., Ltd., resin content 5)
3%) 37.74 g was weighed, and ion-exchanged water was added thereto to make the total amount 100 g to prepare a binder having a resin content of 20%. On the other hand, 40 g of a polyurethane foam chip having a bulk specific gravity (= foam chip weight [g] / apparent volume [cm ³ ]) of 0.04 was weighed in a 2 liter container, and the binder 1 prepared above while stirring the foam chip.
The binder was uniformly wetted and adhered to the entire foam chip by spraying 0 g. Next, a foam chip with a binder attached is used as a test mold (200 mm in length).
× Internal width of 100 mm × height of 20 mm), and compressed with dry hot air (110 ° C
A discharge pressure of 3 Kg / cm ² ) was blown in for 8 minutes to dry and cure the binder, and the cured cured product in the dry state was taken out from the mold. Foam chip density at this time (= foam chip weight [g] / mold internal volume [cm ³ ])
Was set to 0.1.

Example 2 Aqueous polyurethane emulsion ("Izelax S-
1040 ") 37.74 g was weighed, and a polyamine-based water resistance improver (trade name" Aizerax additive B-2 "was added to this.
0 ", Hodogaya Chemical Co., Ltd., 0.38 g was added, and ion-exchanged water was further added to make the total amount 100 g to prepare a binder having a resin content of 20%. A cured molded product was obtained in the same manner as in 1.

Example 3 Polyacrylic ester emulsion (trade name "Movinyl DM-772", Hoechst Synthetic Co., Ltd., resin component 4)
6%) 43.49 g was weighed, and a water-soluble epoxy resin-based water resistance improver (trade name “Denacol EX-313”,
After adding 2 g of Nagase Kasei Co., Ltd., ion-exchanged water was further added to adjust the total amount to 100 g to prepare a binder. A cured molded article was obtained in the same manner as in Example 1 except that this binder was used.

Example 4 40 g of poly (ethylene / vinyl acetate) copolymer emulsion (trade name "Panflex OM-2000", manufactured by Kuraray Co., Ltd., resin content 50%) was weighed, and a water-soluble epoxy resin system was added thereto. Water resistance improver (trade name "Denacol EX-81
2 ", manufactured by Nagase Kasei Co., Ltd.), and ion-exchanged water was further added to make a total amount of 100 g to prepare a binder. A cured molded product was prepared in the same manner as in Example 1 except that this binder was used. Got

Example 5 Poly (styrene / butadiene) copolymer emulsion (trade name "Nippol Lx-430", Nippon Zeon Co., Ltd.)
40.9 g of resin content (resin content 49%) was weighed, and a water-soluble epoxy resin water resistance improver (trade name "Denacol EX-
614 ″, manufactured by Nagase Kasei Co., Ltd.) was added, and then ion-exchanged water was further added to adjust the total amount to 100 g to prepare a binder.
A cured molded product was obtained in the same manner as in.

Example 6 Polyvinyl acetate emulsion (trade name "Movinyl-6"
00L ", Hoechst Synthetic Co., Ltd., resin content 40%) 50
g of water-soluble epoxy resin water resistance improver (trade name "Denacol EX-211", Nagase Kasei Co., Ltd.)
2 g) and 1 g of a polyamine-based water resistance improver (tetraethylenepentamine) were added, and ion-exchanged water was further added to adjust the total amount to 100 g to prepare a binder. A cured molded article was obtained in the same manner as in Example 1 except that this binder was used.

Example 7 Aqueous polyurethane emulsion ("Izelax S-
1040 ″) 18.87 g was weighed, and 2 g of a water-soluble epoxy resin water resistance improver (glycerol polyglycidyl ether) was added, and then ion-exchanged water was added to make the total amount 100 g to obtain a binder having a resin content of 20%. A cured molded article was prepared in the same manner as in Example 1 except that this binder was used.

Comparative Example (Conventional Method) Polyoxypropylene glycol (average molecular weight 200
0) 500 g and tolylene isocyanate 62.25 g were reacted at 85 ° C. for 4 hours in a nitrogen-sealed container equipped with a stirrer to obtain a polyurethane prepolymer having isocyanate at both ends (containing 1.61% of active isocyanate). . After cooling this polyurethane prepolymer to room temperature, 2249.0 g of dichloroethylene as a solvent was added and dissolved uniformly to prepare a solvent-type polyurethane (reaction-curable binder) having a resin content of 20%. On the other hand, 40 g of a polyurethane foam chip having a bulk specific gravity of 0.03 was weighed into a 2 liter container, and 10 g of the reaction-curable binder prepared above was sprayed while stirring the foam chip,
The binder was uniformly wetted and adhered to the entire foam chip. Next, the foam chip with the binder attached is used as a test mold (200 mm length × 100 mm width ×
Filled and compressed to a height of 20 mm) and pressurized steam (103 ° C, pressure 1.8 Kg / c) from the mold vent.
m ² ) was blown for 3 minutes to cure the binder, and the cured molded product was taken out of the mold. Since the taken out product was wet with water vapor, it was dried in a drying oven at 90 ° C. for 4 hours to obtain a cured molded product in a dry state. The foam chip density at this time was 0.1 as in the example.

Table 1 shows the results of the aging test, the residual strain test and the wet strength test performed on the cured molded articles obtained in the above Examples and Comparative Examples. Each test method was performed as follows. Aging test: The test was performed according to JIS K-6382 (1978) "Cushion foam rubber test method", item 5.4 "Aging test" (hardness change rate). Residual strain test: The residual strain test was performed according to JIS K-6382 (1978) "Cushion foam rubber test method", item 5.5 "Compression residual strain test". Wet strength test: A foam chip cured molded article having a thickness of 10 mm was dipped as No. 1 dumbbell piece in a 0.1% sodium dioctylsulfosuccinate aqueous solution for 2 hours, and then the tensile strength in a wet state (pulling speed: 200 mm / min. ) Was measured and compared with the rate of decrease in strength.

[0036]

As can be seen from Table 1, the performances of the molded articles of the examples produced by the method of the present invention using the aqueous resin emulsion as the binder are compared with those of the comparative example by the conventional method using the reaction-curable binder. Then, no significant difference in performance was observed between the two. In addition, the molded article of Example 1 to which the water resistance improver is not added tends to have a large decrease rate of strength in a wet state, but in Examples 2 to 7 in which the water resistance improver is added, the reaction Water resistance comparable to that of the molded article of the comparative example obtained by the conventional method using a curable binder was obtained.

[0038]

As described above, according to the present invention, since the aqueous resin emulsion is used as the binder in place of the conventional reaction-curable binder, the following effects can be obtained.

1) Since the isocyanate compound having toxicity as in the reaction-curable binder and the diluent such as the organic halogenated solvent which has the risk of environmental pollution are not used, there is no danger of working and environmental pollution. Don't worry. 2) Since the binder does not contain a curing agent, there is no restriction on the pot life associated with the curing reaction of the curing agent, so work efficiency is not reduced. 3) When the binder is cured in the molding mold, in the present invention, dry hot air is blown into the mold instead of steam as in the conventional method, so that a cured cured product in a dry state can be taken out from the mold. As a result, the step of drying the cured molded product becomes unnecessary, and the process can be simplified and the working efficiency can be improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29K 105: 26

Claims (2)

[Claims] 1. A waste polyurethane foam crushed into chips is uniformly adhered with a binder consisting of an aqueous resin emulsion, which is then filled in a molding mold and blown with hot dry hot air into the mold. A method for producing a polyurethane foam recycled molded article, which comprises drying and curing a resin emulsion and taking out the dried and cured molded article from a mold. 2. A polyurethane emulsion, a polyacrylic acid ester emulsion, a polyvinyl acetate emulsion, a poly (ethylene / vinyl acetate) copolymer emulsion, a poly (styrene / butadiene) copolymer emulsion as the aqueous resin emulsion. The method for producing a recycled polyurethane foam molded article according to claim 1, wherein one or a mixture of two or more selected from the group consisting of the following compounds and modified products thereof is used.