JP4540545B2 - Flexible polyurethane foam moldings - Google Patents

Description

  The present invention relates to a molded product of a flexible polyurethane foam that is hardly discolored by NOx gas or ultraviolet rays.

  The flexible polyurethane foam is obtained by reacting polyol and polyisocyanate in the presence of water and a catalyst, and has excellent lightness, cushioning and durability, so that it is a brassiere as a pad material for clothing. Widely used for pads and shoulder pads.

  Moreover, in general flexible polyurethane foams, aromatic polyisocyanates such as toluene diisocyanate are used as polyisocyanates, but the soft polyurethane foams obtained thereby are markedly yellowed by NOx gas and ultraviolet rays such as sunlight. . However, in the case of apparel, those that turn yellow are not preferred.

  Conventionally, as a method for suppressing yellowing, there are a method in which various antioxidants are used in combination, and a method in which only an aliphatic polyisocyanate is used 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 the flexible polyurethane foam increases. In addition, when only aliphatic polyisocyanate is used as the polyisocyanate, the reactivity becomes low, and it is necessary to use a special type of catalyst or polyol, and there is a problem of lack of versatility.

  In addition, clothing pad materials (bra pads, shoulder pads), etc. need to retain a predetermined shape, so that flexible polyurethane foam that has been processed to a specified thickness is hot-pressed with a thermoforming mold. It is generally performed to form a desired flexible polyurethane foam molded article. Hot press molding is usually performed at around 200 ° C., but there is a problem that the flexible polyurethane foam is yellowed by heat. Moreover, the later the yellowing tends to be promoted as the heat history (heating temperature and heating press time) during hot press molding increases.

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

  The present invention has been made in view of the above points, and can suppress the influence of yellowing due to hot press molding, and is an inexpensive flexible polyurethane foam molded product that does not require the use of a special catalyst or polyol in production. The purpose is to provide.

According to the first aspect of the present invention, there is provided a flexible polyurethane foam molded article obtained by shaping a flexible polyurethane foam obtained by reacting a polyol and a polyisocyanate in the presence of water and a catalyst by hot press molding. Composed of an aliphatic polyisocyanate and an aliphatic and / or alicyclic polyisocyanate, wherein the weight ratio of the aromatic polyisocyanate and the aliphatic and / or alicyclic polyisocyanate is an aromatic polyisocyanate. Isocyanate: aliphatic and / or alicyclic polyisocyanate = 95: 5 to 60:40, and the catalyst is composed only of an amine catalyst .

  According to the present invention, by using an aromatic polyisocyanate together with an aliphatic and / or alicyclic polyisocyanate as a polyisocyanate, it is possible to suppress a decrease in reactivity during foaming of a flexible polyurethane foam. It is possible to eliminate the need to carefully select a catalyst or to examine a combination with a specific polyol, and to make yellowing of a flexible polyurethane foam molded product caused by hot press molding difficult. Furthermore, even when the catalyst is an amine catalyst only and a tin-based catalyst is not used, it is possible to obtain a flexible polyurethane foam in a good foamed state, and by not using a tin-based catalyst only as an amine catalyst, it is possible to form a flexible polyurethane foam. The yellowing of the product can be made more difficult to occur. In the present invention, “aliphatic and / or alicyclic polyisocyanate” means either or both of an aliphatic polyisocyanate and an alicyclic polyisocyanate.

  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, an aromatic polyisocyanate having two or more isocyanate groups and an aliphatic and / or alicyclic polyisocyanate are used in combination. 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 is 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. In addition, the aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate used in combination are not limited to one type, and may be one or more types. For example, one type of aliphatic polyisocyanate and two types of aromatic polyisocyanate may be used in combination.

  The weight ratio of aromatic polyisocyanate to aliphatic polyisocyanate and / or alicyclic polyisocyanate is aromatic polyisocyanate: aliphatic and / or alicyclic polyisocyanate = 95: 5-60: 40 is preferable, and 90:10 to 70:30 is more preferable. When the proportion of aromatic polyisocyanate is larger than the above range, the effect of aliphatic and / or alicyclic polyisocyanate is reduced, whereas when the proportion of aromatic polyisocyanate is less than the above range, the reactivity is reduced. , The foamability is lowered, and it is difficult to foam well with general polyols and catalysts.

  Water is used as a foaming agent, and is preferably about 0.5 to 5.0 parts by weight with respect to 100 parts by weight of polyol.

As the catalyst, it is possible to use what is known as a flexible polyurethane foam, for example, triethylamine, triethylenediamine, diethanolamine, dimethylamino morpholine, N- ethyl morpholine, amine catalysts such as tetramethylguanidine. In particular, it is preferable to use an amine catalyst alone. By using an amine catalyst alone, yellowing can be more effectively suppressed. 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.

  In addition, additives such as foam stabilizers, pigments, antioxidants, light stabilizers, ultraviolet absorbers, and crosslinking agents can be appropriately blended. The foam stabilizer is not particularly limited 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 foam of the clothing pad material. Antioxidants include phenol- and amine-based radical chain inhibitors (primary antioxidants) and sulfur- 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.

  The flexible polyurethane foam is formed by a known production method in which a polyurethane foam raw material composed of the polyol, polyisocyanate, water, catalyst, and appropriate additives is mixed with a stirrer to cause the polyol and polyisocyanate to react and foam. .

  The flexible polyurethane foam obtained by the foaming is cut to a required thickness, and then shaped by hot press molding with a thermoforming mold having a mold surface of a predetermined shape to obtain a desired flexible polyurethane foam molded article. The

  The hot press molding preferably has a temperature of 180 ° C. to 230 ° C. and a press time of 30 seconds to 3 minutes, more preferably a temperature of 190 ° C. to 210 ° C. and a press time of 30 seconds to 3 minutes. The thickness is preferably set within the above range. The degree of compression at the time of hot press molding is sufficient if the flexible polyurethane foam is deformed along the mold surface of the thermoforming mold at the time of hot pressing. Specifically, the mold surface shape of the thermoforming mold or the flexible polyurethane to be hot press molded It is determined according to the density of the foam and the required hardness of the molded product of the flexible polyurethane foam.

  Examples of the present invention will be specifically described below together with comparative examples. Each component shown in Table 1 was put into a reaction vessel in accordance with the blending ratio in the same table, stirred according to a conventional method for producing a flexible polyurethane foam, and reacted with a polyol and a polyisocyanate to produce a flexible polyurethane foam. At that time, the foaming state was confirmed. The polyol is a product name: GP3000 (polyoxyalkylene polyol, OHV = 56, molecular weight 3000), manufactured by Sanyo Chemical Industries, Ltd., and the crosslinking agent is a product name: PP-200 (polyoxypropylene glycol), manufactured by Sanyo Chemical Industries, Ltd. Amine catalyst is product name: LV33 (triethylenediamine 33% propylene glycol solution), manufactured by Chukyo Yushi Co., Ltd., tin catalyst is product name: DABCO T-9 (Stanas octoate), Air Products Co., Ltd., foam stabilizer is product name: SZ1136 (polyalkylene-modified silicone), manufactured by Nippon Unica Co., Ltd., light stabilizer is product name: Tinuvin 571 (benzotriazole-based compound), manufactured by Ciba Specialty Chemicals Co., Ltd., antioxidant is product name: Irganox 1135 (phenol-based compound), Ciba Spa Aromatic polyisocyanate manufactured by Jalty Chemicals, Inc., product name: Coronate T-80 (toluene diisocyanate), manufactured by Nippon Polyurethane Industry Co., Ltd., alicyclic polyisocyanate manufactured by ISOCYNAT IPDI (isophorone diisocyanate), manufactured by Degussa Co. . Moreover, the numerical value of each component in Table 1 is parts by weight.

  The flexible polyurethane foam thus obtained was cut to a thickness of 10 mm to form a test piece. The initial YI value was measured with respect to this test piece with a YI value measuring device (COLOUR COMPUTER SM-4, manufactured by Suga Test Instruments).

  The flexible polyurethane foam was cut to a thickness of 10 mm, and then hot press molded to 3 mm with a hot press mold to obtain a shaped flexible polyurethane foam molded product. The mold surface shape of the hot press mold is a flat plate shape. The flexible polyurethane foam molded product thus obtained was subjected to a NOx yellowing test and the YI value was measured. In the NOx yellowing test, first, a test piece 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 2 hours, the test piece was taken out, and the same procedure was repeated again on the test piece. After leaving the test piece in nitrogen dioxide for 2 hours, the test piece was taken out and the YI value was measured. The results are as shown in Table 1. The temperature in the YI value column after exposure to NOx with press in Table 1 indicates the hot press molding temperature, and the time indicates the press time.

  As is clear from Table 1, the YI value of the NOx yellowing test result of the flexible polyurethane foam molded article (with press) of the example is smaller than that of the flexible polyurethane foam molded article (with press) of the comparative example. It turns out that it is difficult. Therefore, the flexible polyurethane foam molded product of the present invention comprising a hot press molded product is not easily yellowed by NOx gas, and is suitable for clothing requiring prevention of yellowing.

Claims (1)

In a flexible polyurethane foam molded product formed by hot press molding of a flexible polyurethane foam obtained by reacting a polyol and a polyisocyanate in the presence of water and a catalyst, the polyisocyanate is an aromatic polyisocyanate and an aliphatic polyisocyanate. And / or alicyclic polyisocyanates ,
The weight ratio of the aromatic polyisocyanate and the aliphatic and / or alicyclic polyisocyanate is aromatic polyisocyanate: aliphatic and / or alicyclic polyisocyanate = 95: 5-60: 40,
A flexible polyurethane foam molded article, wherein the catalyst comprises only an amine catalyst .