JPH0116426B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyurethane foam, and more particularly to a method for producing a regeneration solution from cutting waste or molded products thereof that can be used again as a raw material for polyurethane foam. Polyurethane foam is used as a cushion material for pine cushions, seat cushions, etc.
It has a wide variety of uses such as clothing and interior decoration materials, and is used widely and in large quantities. These polyurethane foam products are not only directly formed by mold foaming, but also by continuous foaming to produce large foam blocks, commonly called bread, which are then cut into predetermined dimensions. By the way, when manufacturing various polyurethane foam products as described above, for example, when processing and cutting a polyurethane foam bread that has been continuously foamed into a large block into a desired shape,
A large amount of processing waste is generated before the final product is made, and the epidermis and hypodermis of the block-shaped bread have poor surface properties, so they cannot be made into a product.
A large amount of polyurethane foam is generated which ultimately has to be disposed of. On the other hand, when manufacturing polyurethane foam products by mold foaming, defective molded products or so-called "balls" formed when foaming solution spills out of the mold from the gas vent holes may occur.
There is a considerable amount of polyurethane foam that cannot be made into products. For this reason, methods to effectively utilize these cut scraps and defective products have been raised as an issue for consideration.One example is to turn these defective products and processed scraps into chips and mix adhesives into them. Conventionally, a method of manufacturing a so-called chip form by heating and pressurizing and integrating the chips has already been practiced. However, in this method, the specific scope of recycling is limited to chip foam, so it is practically impossible to effectively utilize all of the large quantities of defective products and processing waste. If polyurethane foam could be produced in the same way again using the above-mentioned processing scraps and defective products as raw materials, the range of effective use would be significantly expanded both quantitatively and qualitatively, and there would be no need for disposal. It becomes possible to reduce the amount of unavoidable processing waste and defective products to virtually zero. The present invention has been made in view of the above circumstances, and aims to provide a method for recycling polyurethane foam processing waste and defective products from foam molding as raw materials for manufacturing the same polyurethane foam again. be. That is, the present invention is a method for obtaining a regenerating solution that can be used as a raw material for producing polyurethane foam again from polyurethane foam, which comprises adding an amine catalyst, a tin catalyst, and a fat to a phosphoric ester plasticizer. A urethane foam regenerating solution characterized in that the polyurethane foam is added to a solution containing one or more selected from the group consisting of group organic acids and surfactants, and is dissolved by heating and stirring. This is the manufacturing method. The details of the present invention will be explained below. Generally, polyurethane foam is obtained from an organic isocyanate compound, a polyol compound, and water.The isocyanate component and polyol component undergo a polymerization reaction to grow urethane linkages, and at the same time, the isocyanate component and water undergo the following reaction. A foam structure is formed due to the foaming action of the carbon dioxide gas that is generated.
A polyurethane foam is produced. Note that these reactions generally require the presence of an amine catalyst or a tin catalyst, and a foam stabilizer such as silicone oil is used to obtain a uniform cell structure. -N=C=O+H ₂ O→-NH ₂ +CO ₂ As mentioned above, in the production of polyurethane foam, the growth reaction of the urethane linkage and the foaming reaction using carbon dioxide gas need to be carried out simultaneously. The polyurethane foam, which has already been polymerized and foamed by these reactions, no longer has the ability to carry out the above reactions. Therefore, in order to reuse this polyurethane foam as a raw material for producing polyurethane foam again, it is necessary to dissolve it by an appropriate method and to cut the polyurethane linkage to carry out the above-mentioned polymerization and foaming reactions. must be broken down into components with The present invention uses a phosphoric ester plasticizer as a solvent, and adds one or more selected from amine catalysts, tin media, aliphatic organic acids, or surfactants as catalysts, and heats and dissolves the plasticizers. This is what made it possible. Examples of the phosphoric ester plasticizer in the present invention include phenyl diisopropylphenyl phosphate, diphenyl isopropylphenyl phosphate, trisisopropylphenyl phosphate,
Tris phenyl phosphate, tris methyl phenyl phosphate, tris ethyl phenyl phosphate, tricresyl phosphate, tri-2-
Ethylhexyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, etc. can be used. It is thought that these phosphoric acid ester plasticizers not only act as a simple solvent for the polyurethane warm, but also participate in the reaction of cutting urethane bonds and decomposing the polyurethane into an isocyanate component and a polyol component. As the polyether polyol in the present invention, polyether polyols ranging from bifunctional to polyfunctional can be used alone or in combination. However, due to viscosity and properties, it is difunctional to tetrafunctional, molecular weight
Something between 1000 and 5000 is suitable. Moreover, polyethylene glycol, 1,4-butanediol, etc. can be used as the polyhydroxy compound in the present invention. These polyether polyols and polyhydroxy compounds have been conventionally used as raw materials for manufacturing ordinary polyurethane foams, and by mixing them with the phosphoric ester plasticizer, they can improve the affinity for polyurethane foams. Improved compatibility as a solvent. In addition, when only a phosphoric acid ester plasticizer is used as a solvent, when producing polyurethane foam from the obtained regenerated solution, it is necessary to newly replenish and blend polyether polyol to prepare a foaming stock solution. In contrast, in the case of the present invention, since the polyether polyol and polyhydroxy compound are added to the solvent from the beginning, the formulation and assembly of the foaming stock solution is required even when producing polyurethane foam again from the obtained regenerated solution. This has the effect of making it easier. The polyether polyol compound may be added in any amount within the range of 2000 parts by weight per 100 parts by weight of the phosphoric ester plasticizer. As the amine catalyst in the present invention, triethylenediamine, triethanolamine, diethanolamine, monoethanolamine, triethylamine, ethylenediamine, n-ethylmorpholine, etc. can be used. As the tin catalyst in the present invention, starus octoate, dibutyltin dilaurate, etc. can be used. As the aliphatic organic acid in the present invention, stearic acid, oleic acid, linoleic acid, lauric acid, etc. can be used. Further, as the surfactant in the present invention, a cationic surfactant such as a quaternary ammonium salt or an amine salt, or an anionic surfactant such as a phosphate ester salt can be used. In the present invention, the amine catalyst, tin catalyst, aliphatic organic acid, and surfactant promote the decomposition reaction of the urethane linkage, and the total amount of these is 100% by weight of the phosphoric ester plasticizer. It is desirable to add it in an amount of 0.5 parts by weight or more. When carrying out the present invention, first, the above-mentioned polyether polyol compound and, if necessary, the above-mentioned polyhydroxy compound were added and mixed to the above-mentioned phosphoric acid ester plasticizer, and then the above-mentioned amine catalyst, tin catalyst, etc. were added. Prepare the digestion solution. Subsequently, polyurethane foam may be added to the solution and dissolved by heating and stirring. At this time, it is preferable to add the polyurethane foam little by little in the form of small pieces, but it may also be added in large chunks. Moreover, the polyurethane foam may be added after the decomposition solution is heated to a predetermined temperature in advance, or the polyurethane foam may be mixed into the decomposition solution and then heated and stirred. The heating temperature at that time varies depending on the properties of the polyurethane foam to be melted, but is generally around 150℃~
A temperature of about 250℃ is sufficient. When the polyurethane foam is added while being heated to a constant temperature and stirred, it gradually dissolves and decomposes into a liquid with increased viscosity, yielding the desired regenerated solution. In that case, the amount of polyurethane foam strips added depends on the concentration of the regeneration solution to be obtained, but as a rough guide, it is per 100 parts by weight of the plasticizer mentioned above.
A range of up to 800 parts by weight is preferred. If a larger amount is added than this, the decomposition will not proceed as expected, and the resulting regenerated solution will also tend to solidify when cooled to room temperature. In this sense, a more preferable addition range of polyurethane foam is 100 to 300 parts by weight. The regeneration solution obtained as described above contains the phosphoric acid ester plasticizer and polyether polyol (sometimes also containing polyhydroxy compounds) used as a solvent, as well as amine catalysts, tin catalysts, aliphatic organic acids, surfactants, etc. In addition to the agent and catalyst, it also contains a urethane decomposition solution. In order to produce polyurethane foam using this regenerated solution, the regenerated solution may be added as an extender to a usual raw material formulation for producing polyurethane foam, and foamed in accordance with a conventional method. In this case, since the above-mentioned regenerated solution contains the polyether polyol added as a solvent in addition to the polyol component generated by decomposition of the polyurethane foam, it is natural that the newly blended isocyanate compound and polyol compound can be significantly reduced compared to conventional polyurethane foam production.
In some cases, there is no need to newly add or blend a polyol component. The remanufactured polyurethane foam has excellent elasticity, specific gravity, hardness, tensile strength, tear strength,
In terms of elongation, etc., it has approximately the same properties as polyurethane foam manufactured from ordinary raw material formulations. In addition, since the phosphoric ester plasticizer used as a solvent has traditionally been highly evaluated as a flame retardant, it is recommended to use a larger amount of the phosphoric ester plasticizer than polyether polyol compounds or polyhydroxy compounds. In this case, the recycled polyurethane foam can have excellent flame retardancy. Examples of the present invention will be described below. Example 1 (1) Production of regeneration solution 200 g of triphenyl phosphate and molecular weight
3000, trifunctional polyether polyol 800g
and 60 g of a triethylene diamine solution (a mixture of triethylene diamine and a trifunctional polyether polyol with a molecular weight of 3000 heated at a ratio of 1:4) were weighed and mixed into a stainless steel container, and the soft polyurethane was added into the container. After adding 300g of foam strips and mixing the whole thing,
It was heated to 180°C using a heater and stirred.
When the introduced soft polyurethane foam is almost dissolved, add the soft polyurethane foam pieces little by little while heating and stirring.
A total of 1000g was dissolved. Final temperature is 210
It was warm at ℃. The polyurethane foam regeneration solution thus obtained was a highly viscous liquid at room temperature. (2) Manufacture of polyurethane foam using the above regenerated solution A foaming solution of polyurethane foam was prepared according to the following formulation, and a soft polyurethane foam was obtained by foaming this by a one-shot method. Above regeneration solution 85wt molecular weight 3000, trifunctional polyether polyol
15 〃 Triethylenediamine 0.08 〃 Stanus octoate 0.13 〃 N-Ethylmorpholine 0.35 〃 Water 4.5 〃 Silicone oil 1.2 〃 Trichlorofluoromethane 2.0 〃 Tolylene diisocyanate 57.0 〃 In addition, as a comparative example, polyurethane foam consisting of the following ordinary formulation was used. Undiluted solution A soft polyurethane foam was produced by foaming using the same one-shot method as in the above example. Molecular weight 3000, trifunctional polyether polyol
100 parts by weight Triethylenediamine 0.1 〃 Stanus octoate 0.08 〃 n-ethylmorpholine 0.35 〃 Water 4.3 〃 Silicone oil 1.2 〃 Trichlorofluoromethane 2.0 〃 Tolylene diisocyanate 55.0 〃 (3) Characteristic tests When various physical properties were tested for each of the soft polyurethane worms obtained, the results shown in Table 1 below were obtained.

[Table] As described above, the physical properties of the flexible polyurethane foams obtained in Examples were almost unchanged compared to those obtained in Comparative Examples. Example 2 (1) Production of regeneration solution 200 g of octyl diphenyl phosphate,
Molecular weight 3000, trifunctional polyether polyol
700g, polyethylene glycol 100g, dibutyltin dilaurate 15g, cationic surfactant and quaternary ammonium salt total 5g
were weighed and mixed in a stainless steel container. Next, while heating this solution using a heater, 1000 g of soft polyurethane foam strips were added little by little and dissolved therein. The final temperature was 200°C. The polyurethane foam regeneration solution thus obtained was a highly viscous liquid at room temperature. (2) Production of polyurethane foam using the above regenerated solution Polyurethane foam with a specific gravity of 0.020 was produced in the same manner as in Example 1 using the regenerated solution obtained above. A polyurethane foam whose physical properties were almost the same as that of the polyurethane foam was obtained. Example 3 (1) Production of regeneration solution 150 g of phenyl diisopropylphenyl phosphate, 850 g of trifunctional polyether polyol with a molecular weight of 3000, and 15 g of dibutyltin dilaurate were weighed and mixed in a stainless steel container, and heated. It was heated to 160°C using a heater.
Subsequently, small pieces of flexible polyurethane foam were added little by little into the decomposed solution with stirring to dissolve 1500 g of polyurethane foam. The final temperature was 210°C. In this way, a regenerated solution of polyurethane foam was obtained as a liquid with high viscosity at room temperature. (2) Production of polyurethane foam using the above regenerated solution A foaming stock solution of polyurethane foam was prepared according to the following formulation, and a soft polyurethane foam was obtained by foaming this by a one-shot method. 100 parts by weight of the above regeneration solution Triethylenediamine 0.10 Stanus octoate 0.13 n-ethylmorpholine 0.35 Water 4.5 Silicone oil 1.2 Trichlorofluoromethane 2.0 Tolylene diisocyanate 55.5 In addition, as a comparative example, the following normal formulation A soft polyurethane foam was produced by foaming using the same one-shot method as in the above example using a polyurethane foaming stock solution consisting of: Molecular weight 3000, trifunctional polyether polyol
100 parts by weight Triethylenediamine 0.1 〃 Stanus octoate 0.08 〃 n-ethylmorpholine 0.35 〃 Water 4.3 〃 Silicone oil 1.2 〃 Trichlorofluoromethane 2.0 〃 Tolylene diisocyanate 55.0 〃 (3) Characteristic tests When various physical properties were tested for each of the flexible polyurethane foams obtained, the results shown in Table 2 below were obtained.

[Table] As described above, the physical properties of the flexible polyurethane foams obtained in Examples were almost unchanged compared to those obtained in Comparative Examples. As described in detail above, according to the present invention, it is possible to obtain recycled solution raw materials that can be used to re-manufacture the same polyurethane foam from processing and cutting waste of polyurethane foam and defective products during foam molding. Very remarkable effects can be obtained, such as the effective use of good products.

Claims (1)

[Claims] 1 A method for obtaining a regenerating solution that can be used as a raw material for producing polyurethane foam again from polyurethane foam, the method comprising: a mixed solution of a phosphoric acid ester plasticizer and a polyether polyol, or a polyhydroxy solution added to the mixed solution. A solution in which one or more selected from the group consisting of an amine catalyst, a tin catalyst, an aliphatic organic acid, and a surfactant is added to a compound is used as a decomposition liquid, and in the decomposition liquid A method for producing a polyurethane foam regenerating solution, which comprises adding the polyurethane foam to the solution and dissolving it by heating and stirring.