JP5116981B2 - Method for producing polyurethane foam molded article - Google Patents

Description

The present invention relates to a polyurethane foam molded article formed by plastic deformation by heat compression, and particularly relates to a method for producing a polyurethane foam molded article which is not easily discolored yellow (hereinafter referred to as yellowing) and is suitable for clothing. .

  Polyurethane foam is foamed from a foaming raw material containing polyol, polyisocyanate, foaming agent and catalyst, and has excellent lightness, cushioning and durability. Widely used for pads and shoulder pads.

  In general, polyurethane foams are markedly yellowed by NOx gas and ultraviolet rays such as sunlight. Therefore, suppression of yellowing is desired for clothing applications.

  Conventionally, as a method for suppressing yellowing, there are a method using a combination of various antioxidants and a method using only an aliphatic polyisocyanate as a polyisocyanate. However, in the method of using various antioxidants in combination, there is a problem that the raw material becomes expensive and the product price of polyurethane foam increases. Further, when only an aliphatic polyisocyanate is used as the polyisocyanate, the reactivity becomes low, and it is necessary to use a special type of catalyst or polyol.

  In addition, because it is necessary to maintain a predetermined shape for clothing pad materials (bra pads, shoulder pads), etc., polyurethane foam that has been processed to a specified thickness is plastically deformed by heat compression that is pressed with a thermoforming mold. And molded into a desired polyurethane foam molded product. However, there has been a problem that yellowing of the polyurethane foam is promoted by heat at the time of heat compression, and that the polyurethane foam molded product is markedly yellowed by the subsequent change over time.

JP 2005-48038 A JP 2000-226429 A Japanese Patent Laid-Open No. 10-36543

The present invention has been made in view of the above points, and provides a method for producing a polyurethane foam molded article capable of suppressing the adverse effect of yellowing due to heat compression for shaping and lessening yellowing due to subsequent aging. Objective.

The invention of claim 1 relates to a method for manufacturing a polyurethane foam molded article shaping by plastically deformed by heat compressing polyurethane foam containing dithiocarbamate compound.

The invention of claim 2 is characterized in that, in claim 1, the amount of the dithiocarbamate compound is 0.1 to 2.0 parts by weight with respect to 100 parts by weight of polyol in the foaming raw material of the polyurethane foam. To do.

According to the present invention, since the polyurethane foam contains a dithiocarbamate compound, adverse effects on yellowing due to heat compression for shaping can be suppressed, and yellowing due to subsequent aging can be reduced.

The polyurethane foam molded article of the present invention is formed by plastic deformation of a polyurethane foam containing a dithiocarbamate compound by heat compression.

The polyurethane foam is obtained by foaming a foaming raw material containing a polyol, a polyisocyanate, a foaming agent, a catalyst, a dithiocarbamate compound and an appropriate additive.

  As the polyol used in the present invention, an ether-based polyol or an ester-based polyol known for use in flexible polyurethane foams can be used. Examples of ether polyols include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, and sucrose, or polyhydric alcohols thereof. The polyether polyol which added alkylene oxides, such as ethylene oxide and a propylene oxide, can be mentioned. As ester polyols, polycondensation of aliphatic carboxylic acids such as malonic acid, succinic acid and adipic acid and aromatic carboxylic acids such as phthalic acid and aliphatic glycols such as ethylene glycol, diethylene glycol and propylene glycol. The polyester polyol obtained in this way can also be used.

  As the polyisocyanate, those known for flexible polyurethane foams can be used. That is, one or more of aromatic, aliphatic, and alicyclic polyisocyanates having two or more isocyanate groups are used.

  The aromatic polyisocyanate refers to a polyisocyanate having an aromatic ring, and examples thereof include toluene diisocyanate (TDI), diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and polymeric polyisocyanate (crude MDI). On the other hand, the aliphatic polyisocyanate refers to a polyisocyanate having an isocyanate group attached to a linear hydrocarbon chain, and examples thereof include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate. The alicyclic polyisocyanate refers to a polyisocyanate having an isocyanate group on a cyclic hydrocarbon chain, and examples thereof include isophorone diisocyanate (IPDI) and dicyclohexamethane diisocyanate. Other prepolymers can also be used.

  As the foaming agent, those known for flexible polyurethane foams can be used. For example, water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide gas and the like can be mentioned, and water is particularly suitable as a blowing agent. The amount of the blowing agent is preferably about 0.5 to 5.0 parts by weight with respect to 100 parts by weight of the polyol.

  As the catalyst, those known for flexible polyurethane foams can be used, such as amine catalysts such as triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, tetramethylguanidine, stannous octoate, and the like. And tin catalysts such as dibutyltin dilaurate and metal catalysts (also referred to as organometallic catalysts) such as phenylmercury propionate or lead octenoate. The general amount of the catalyst is about 0.01 to 2.0 parts by weight with respect to 100 parts by weight of the polyol.

Examples of the dithiocarbamate compound include pentamethylenedithiocarbamate piperidine salt, pipecolyldithiocarbamate pipecoline salt, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, N- Examples include zinc pentamethylenedithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, and tellurium diethyldithiocarbamate. The amount of the dithiocarbamate compound is 0.1 to 2 parts by weight, preferably 0.2 to 1.0 parts by weight, based on 100 parts by weight of the polyol. When the amount of the dithiocarbamate compound is less than 0.1 parts by weight, it becomes difficult to obtain the yellowing prevention effect of the polyurethane foam molded product, whereas when it exceeds 2 parts by weight, it becomes an addition more than the necessary amount for preventing yellowing Moreover, it becomes difficult to obtain a good polyurethane foam by increasing the acid content.

  In addition, additives such as foam stabilizers, pigments, antioxidants, light stabilizers, ultraviolet absorbers, and crosslinking agents can be appropriately blended. Any foam stabilizer may be used as long as it is used for flexible polyurethane foams, and examples thereof include silicone foam stabilizers, fluorine-containing compound foam stabilizers, and known surfactants. As the pigment, those according to the required color are used. In particular, a white pigment is preferable as the pigment in the polyurethane foam of the clothing pad material. Antioxidants include phenol-based and amine-based radical chain inhibitors (primary antioxidants) and sulfur-based and phosphorus-based peroxide decomposers (secondary antioxidants). If this is done, a synergistic effect can be obtained. As the light stabilizer, a hindered amine having a hindered piperidine skeleton can be used. Examples of the ultraviolet absorber include benzotriazole, benzophenone, benzoate, and cyanoacrylate. Examples of the crosslinking agent include ethylene glycol, 1,3-propanediol, 1,4-butanediol, glycerin, diethanolamine, triethanolamine, and ethylenediamine.

Moreover, the polyurethane foam before the heat compression consists of a slab foamed product obtained by foaming the foaming material by a slab foaming method and cut into a predetermined size. The slab foaming method is a method in which the foaming raw material is prepared with a predetermined composition, and then the foaming raw material is reacted at room temperature and atmospheric pressure, and is a known method for producing flexible polyurethane foam. Specifically, a foaming raw material composed of the polyol, polyisocyanate, foaming agent, catalyst, dithiocarbamate compound and appropriate additives is mixed with a stirrer, and the stirring mixed foaming raw material is moved on a conveyor belt moving in one direction. It is carried out by making it discharge and making it foam on a conveyor belt.

  The polyurethane foam after the cutting is pressed by a thermoforming mold having a mold surface of a predetermined shape and subjected to heat compression molding to be plastically deformed to obtain a polyurethane foam molded product having a desired shape.

  The heat compression is set to the temperature, compression time, and compression level of a thermoforming mold that can plastically deform polyurethane foam. Specifically, the temperature of the thermoforming die is preferably 160 ° C. to 250 ° C. and the pressing time is preferably 2 to 8 minutes, more preferably the temperature of the thermo forming die is 180 ° C. to 230 ° C. and the pressing time is 3 to 6 minutes. It is set within the above range depending on the thickness of the polyurethane foam to be heat compression molded. The compression degree at the time of heat compression may be a compression degree that allows the polyurethane foam to be deformed along the mold surface of the thermoforming mold. Specifically, the mold surface shape of the thermoforming mold or the polyurethane foam to be heat compression molded It is determined according to the density, hardness required of the polyurethane foam molded product, and the like.

Examples of the present invention will be specifically described below together with comparative examples. Polyurethane foam is formed by the slab foaming method in which each of the ingredients shown in Tables 1 and 2 is mixed with the mixing ratios in the same table, mixed with a stirrer, discharged onto a conveyor belt, and foamed at room temperature under atmospheric pressure. did. Those Examples 1-3 having different dithiocarbamate compounds, those examples 4～5,8～9 is obtained by changing the amount of dithiocarbamate compounds, when Examples 5-7 are then heat compression This is for changing the heating temperature. Further, Comparative Examples 1 to 5 were obtained by using antioxidants 1 to 5 in place of the dithiocarbamate compounds 1 to 3 in Examples, and Comparative Example 6 did not include any of the dithiocarbamate compound and the antioxidant. Is.

The polyols in the table are product names: SANNICS GP3050F (polyoxyalkylene polyol, OHV = 56, molecular weight 3000), manufactured by Sanyo Chemical Industries, Ltd., amine catalyst is 33LV (triethylenediamine 33% propylene glycol solution), Chukyo Yushi Co., Ltd. Made by company, tin catalyst is product name: MRH-110 (dibutyltin dilaurate), manufactured by Johoku Chemical Industry Co., Ltd., foam stabilizer is product name: F650 (silicone foam stabilizer), manufactured by Shin-Etsu Chemical Co., Ltd., polyisocyanate is product name: Coronate T-80 (toluene diisocyanate), manufactured by Nippon Polyurethane Industry Co., Ltd., dithiocarbamate compound 1 is product name: Noxeller ZTC (zinc dibenzyldithiocarbamate), manufactured by Ouchi Shinsei Chemical Co., Ltd., dithiocarbamate compound 2 is product name : Noxeller EZ (Zinc diethyldithiocarbamate), manufactured by Ouchi Shinsei Kagaku Kogyo Co., Ltd., dithiocarbamate compound 3 is product name: Noxeller ZP (Z-N-pentamethylenedithiocarbamate zinc), manufactured by Ouchi Eki Kagaku Kogyo Co., Ltd., antioxidant 1 Product name: Noxeller M (2-mercaptobenzothiazole), manufactured by Ouchi Shinsei Chemical Co., Ltd., Antioxidant 2 is product name: Noxeller MSA-G (N-oxydiethylenebenzothiazole-2-sulfenamide), Ouchi Shinsei Made by Chemical Industry Co., Ltd., Antioxidant 3 is product name: NOCRACK MB (2-mercaptobenzimidazole), manufactured by Ouchi Shinsei Chemical Co., Ltd., Antioxidant 4 is product name JP-308E (Tris (2-ethylhexyl) phosphite) ), Manufactured by Johoku Chemical Industry Co., Ltd., antioxidant 5 is product name AO-503 (thioether acid) Inhibitor), it is made by Asahi Denka Kogyo Co., Ltd..

  The polyurethane foam slab foam product thus obtained was cut into a thickness of 10 mm × 50 mm × 50 mm to form a test piece. With respect to this test piece, the YI value (initial YI value) before heating and compression was measured with a YI value measuring device (COLOUR COMPUTER SM-4, manufactured by Suga Test Instruments).

  Further, the test piece cut to a thickness of 10 mm × 50 mm × 50 mm is plastically deformed by heating and compressing it to a thickness of 50% (5 mm) for a predetermined time by using a thermoforming mold at a predetermined temperature, so that a mold surface shape is obtained. A shaped polyurethane foam molded article was obtained. The mold surface shape of the thermoforming die is a flat plate shape. Tables 3 and 4 show the heat compression temperature (temperature of the thermoforming mold) and the heat shrinkage time. Moreover, the YI value after heat-compression and the YI value after exposure to NOx gas for 3 hours were measured for the polyurethane foam molded article thus obtained. In the NOx 3 hour exposure method, first, a polyurethane foam molded article is set in a desiccator, and about 2 ml (milliliter) of 99.9% nitrogen dioxide is collected with a syringe and injected into the desiccator. After stirring at 400 rpm for 5 minutes, when the concentration of nitrogen dioxide gas is measured with a detector tube (manufactured by Gastec), it becomes approximately 10 ppm. After leaving in that state for 3 hours, the polyurethane foam molded article was taken out and the YI value was measured. Furthermore, the difference between the YI value before the heat compression and the Y1 value after the heat compression, and the difference between the YI value after the heat compression and the YI value after the NOx 3 hour exposure were obtained. The measurement results and differences of YI values are as shown in Tables 3 and 4.

Table 3 and Table 4, a polyurethane foam molded article of Example 1-9 containing dithiocarbamate compounds, compared to Comparative Examples 1-6 containing no dithiocarbamate compound polyurethane foam moldings, It can be seen that the difference between the YI value after heat compression and the YI value after exposure to NOx for 3 hours is small, and yellowing is suppressed. From this, it can be seen that the polyurethane foam molded articles of Examples 1 to 9 containing the dithiocarbamate compound have little adverse effect on yellowing due to heat compression, and are hardly yellowed due to changes over time after heat compression. . Therefore, the polyurethane foam molded article of the present invention comprising a plastically deformed product by heat compression has little adverse effect on yellowing due to heat compression and is difficult to yellow due to subsequent aging, and particularly clothing that requires prevention of yellowing. It is suitable for use.

Claims (2)

Polyurethane foam moldings manufacturing method of shaping by plastic deformation by heat compressing polyurethane foam containing dithiocarbamate compound. Production of polyurethane foam molded article of claim 1 wherein the amount of said dithiocarbamate compound is 0.1 to 2.0 parts by weight per 100 parts by weight of polyol in the foam material of the polyurethane foam Way .