JP5014827B2 - Flexible polyurethane foam - Google Patents

Description

  The present invention relates to a flexible polyurethane foam capable of suppressing discoloration due to NOx gas, and particularly to a flexible polyurethane foam for thermoforming capable of suppressing discoloration due to NOx gas in use after thermoforming.

  Since flexible polyurethane foam has excellent lightness, cushioning and durability, it is widely used in clothing applications, particularly as a pad material for clothing such as brassiere pads and shoulder pads. Usually, a flexible polyurethane foam is obtained by reacting a polyol and an isocyanate in the presence of a blowing agent, a catalyst and an antioxidant.

  In addition, flexible polyurethane foam has a tendency to turn yellow due to changes over time, which is not preferred for clothing applications (hereinafter referred to as yellowing. In addition, a tendency excellent in discoloration resistance is referred to as difficult yellowing). There is a need for improvement.

  The yellowing is said to be caused by a chemical change caused by ultraviolet rays or nitrogen oxide gas (NOx gas) in a flexible polyurethane foam, and a yellow chromophore being formed in the molecular structure of the polyurethane. As a polyurethane raw material forming the chromophore, BHT (butylated hydroxytoluene) used as an antioxidant is known, and it has been proposed to change and modify this antioxidant ( Patent Document 1). Moreover, the method of suppressing NOx yellowing by using a hindered phenol type or phosphorous acid ester type antioxidant is also proposed (patent documents 2-4).

  However, in garment applications, it is common to shape by hot molding (also called hot press molding) in which a flexible polyurethane foam is hot-pressed with a heated mold. However, in the past, yellowing has been studied in a state before thermoforming. In the flexible polyurethane foam, the polymer chain segment is cleaved by thermoforming and is very easily deteriorated, and the yellowing resistance is much worse than the state before thermoforming. Therefore, even if the yellowing resistance is improved before thermoforming, the yellowing resistance may not be improved or slightly improved after thermoforming.

JP 11-323126 A JP 2002-097245 A JP 2002-097246 A JP 2004-323736 A

  This invention is made | formed in view of the said point, Comprising: The yellowing after thermoforming can be suppressed and it aims at provision of the flexible polyurethane foam suitable for clothes.

The invention according to claim 1 is a flexible polyurethane foam obtained by reacting a polyol and an isocyanate in the presence of a foaming agent, a catalyst and an antioxidant. The isocyanate comprises only tolylene diisocyanate, and the catalyst is a reactive amine catalyst. The antioxidant comprises a reactive phosphite ester, and the reactive phosphite ester is tris (dipropylene glycol) phosphite .

  In the present invention, the isocyanate is only tolylene diisocyanate, the catalyst is only an amine catalyst containing a reactive amine catalyst, and the antioxidant contains a reactive phosphite, so that the softness after thermoforming The yellowing of the polyurethane foam can be effectively suppressed. Unlike the non-reactive amine catalyst, the reactive amine catalyst reacts with isocyanate when the flexible polyurethane foam is foamed and does not remain free in the flexible polyurethane foam, so the yellowing of the flexible polyurethane foam after thermoforming The prevention effect is increased. Similarly, reactive phosphite also reacts with isocyanate during foaming of the flexible polyurethane foam and does not remain free in the flexible polyurethane foam, so the yellowing prevention effect of the flexible polyurethane foam after thermoforming is high. can do.

  Moreover, since a reactive amine catalyst has low catalytic activity compared with the other catalyst currently used widely for flexible polyurethane foams, in this invention, tolylene diisocyanate is used in order to supplement it. Furthermore, in the present invention, the catalyst may be only a reactive amine catalyst, but in that case, the catalyst activity is low, and a flexible polyurethane foam having a good foamed state may not be obtained. Therefore, in the present invention, the catalyst is composed of an amine catalyst including a reactive amine catalyst, and the combined use of the reactive amine catalyst and another amine catalyst is not excluded. In addition, in the present invention, the reactive amine catalyst is essential, thereby reducing the amount of non-reactive amine catalyst and improving yellowing resistance after thermoforming, and realizing a good foamed state of flexible polyurethane foam. is doing.

  Furthermore, in the present invention, attention is paid to the fact that the use of a metal catalyst facilitates yellowing of the flexible polyurethane foam after thermoforming, and only an amine catalyst containing a reactive amine catalyst is used as a catalyst, and no metal catalyst is used. Thus, the yellowing prevention effect of the flexible polyurethane foam after thermoforming is further enhanced.

  The reactive phosphite may be used alone as an antioxidant in the present invention, but the combination of hindered phenol hydroperoxide generation ability and non-radical decomposition of phosphite hydroperoxide. In order to produce a synergistic effect on oxidation resistance deterioration, it is preferable to use in combination with other antioxidants. Therefore, in the present invention, the reactive phosphorous acid ester is included in the antioxidant, and the combined use of the reactive phosphorous acid antioxidant and another antioxidant is not excluded.

  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 isocyanate, only tolylene diisocyanate (TDI) which is a kind of aromatic isocyanate is used. Tolylene diisocyanate includes 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, and any of them can be used. Tolylene diisocyanate is preferable because it is inexpensive and has good reactivity as compared with aliphatic, alicyclic or other aromatic isocyanates. Particularly in the present invention, a highly reactive tolylene diisocyanate is suitable as the isocyanate because the catalyst contains a reactive amine catalyst and the antioxidant contains a reactive phosphite. Furthermore, tolylene diisocyanate having a 2,4-TDI isomer ratio of 80% has a high reaction activity and is more preferable in the production method by the one-shot method.

  As the foaming agent, known ones for flexible polyurethane foams are used, and water is particularly suitable. The amount of water as a blowing agent is preferably about 0.5 to 5.0 parts by weight with respect to 100 parts by weight of polyol.

  As the catalyst, only an amine catalyst including a reactive amine catalyst is used, and a metal catalyst such as a tin catalyst is not used. That is, the reactive amine catalyst is used alone or in combination with other general-purpose amine catalysts (non-reactive amine catalysts) for flexible polyurethane foam. As the reactive amine catalyst, one having a functional group that reacts with isocyanate is used. Further, an amine compound having at least one OH group as a functional group that reacts with isocyanate is preferable. Examples of the reactive amine catalyst comprising an amine compound having at least one OH group include monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine (DMEA), N, N, N′-trimethylaminoethylethanolamine, N , N-dimethylaminoethoxyethanol, N, N-dimethylaminohexanol, N, N-dimethylaminoethoxyhexanol and the like. Two or more reactive amine catalysts may be used.

  Other amine catalysts that can be used with the reactive amine catalyst (non-reactive amine catalyst) include triethylamine, tripropylamine, tributylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine. , Diethyltriamine, N, N, N ′, N′-tetramethylhexanediamine, N, N, N ′, N′-tetramethylpropanediamine, N, N, N ′, N ″, N ″ -penta Examples include amine catalysts such as methyldiethylenetriamine, N, N ′, N′-trimethylaminoethylpiperazine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, and triethylenediamine. Moreover, in this invention, yellowing can be suppressed more effectively by not using a metal catalyst as a catalyst. 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 particular, the amount of the reactive amine catalyst is preferably 5% by weight to 100% by weight with respect to the whole catalyst. More preferably, the reactive amine catalyst is used in combination with another amine catalyst. In this case, the more preferable amount of the reactive amine catalyst is 10% by weight or more and less than 100% by weight based on the total amount of the catalyst.

  As the antioxidant, an antioxidant composed of a reactive phosphite is essential. Tris (dipropylene glycol) phosphite is suitable as an antioxidant comprising a reactive phosphite.

  The antioxidant is not limited to one type, and a plurality of types may be used. The combined use of the reactive phosphite and other antioxidants is particularly preferable because a synergistic effect against oxidation-resistant deterioration is produced as described above. The antioxidant that can be used together with the reactive phosphite is not limited, and examples thereof include phenol-based, amine-based, sulfur-based, and phosphorus-based agents.

  Examples of antioxidants that can be used with reactive phosphites include pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxylphenyl) propionate], n-octadecyl 3- ( In amine systems such as 3,5-di-t-butyl-4hydroxyphenyl) propionate, triethylene glycol bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], [Octylated diphenylamine, Nn-butylaminophenol, N, N-diisopropyl-p-phenylenediamine, etc. In the case of sulfur, lauryl stearyl thiodipropionate, dilauryl-3,3′-thiodipropionate, distearyl- 3,3'-thiodipropionate, etc. 2,4-di-tert-butylphenol) phosphite, bis (2,4-tert-butylphenyl) pentaerythritol diphosphite, tris (4-n-nonylphenyl) phosphite, tetrakis (2,4-di-) (t-butylphenyl) 4,4'-biphenylene diphosphite, triphenyl phosphite, triisodecyl phosphite and the like.

  The addition amount of the antioxidant is preferably 0.1 to 13 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the polyol. Furthermore, in the case where the antioxidant comprising the reactive phosphite is used in combination with another antioxidant, the preferred amount of the antioxidant comprising the reactive phosphite is 10 with respect to the whole antioxidant. % By weight or more and less than 100% by weight. When the amount of the antioxidant comprising the reactive phosphite is less than the above range, yellowing after thermoforming of the flexible polyurethane foam cannot be effectively suppressed. Moreover, when there is too much whole quantity of antioxidant, it will become easy to produce foaming defect.

  In addition, in the present invention, additives such as a foam stabilizer, a pigment, a light stabilizer, and an ultraviolet absorber 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 foam of the clothing pad material.

  Examples of the light stabilizer include hindered amines having a hindered piperidine skeleton, such as bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and bis (2,2,6,6-tetramethyl). -4-piperidinyl) sebacate, poly ((6-((1,1,3,3-tetramethylbutyl) amino) -s-tetrazine-2,4-didyl) (2,2,6,6-tetramethyl -4-piperidyl) imino) hexamethylene (2,2,6,6-tetramethyl-4-piperidyl) imino))), bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[ 3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate and the like.

  The UV absorber is 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzo, which is a benzotriazole series. Triazole, 2- (2-hydroxy-5- (1,1,3,3-tetraethylbutyl) phenyl) benzotriazole, 2,2′-methylenebis (6- (2Hbenzotriazol-2-yl) -4-1 , 1,3,3- (tetramethylbutyl) phenol), 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- [5-chloro (2H) -benzotriazol-2-yl]- 2-methyl-4-methoxybenzophenone, 5-benzoyl-4-hydroxy, which are benzophenone-based, such as 4-methyl-6- (t-butyl) phenol 2-methoxybenzene sulfonic acid 2-hydroxy-4-n-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2,4-t-butylphenyl-3,5-di-t-butyl which is benzoate type Examples include cyanoacrylate-based ethyl-2-cyano-3,3-diphenyl acrylate, 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, etc. such as -4-hydroxybenzoate.

  In the production of the flexible polyurethane foam in the present invention, the polyol and isocyanate are directly reacted in the presence of a foaming agent, a catalyst, an antioxidant, etc., or the polyol group and the polyisocyanate are reacted in advance to form an isocyanate group at the terminal. The prepolymer can be obtained by any method of the prepolymer method in which a polyol is reacted with the prepolymer in the presence of a foaming agent, a catalyst, an antioxidant and the like. Moreover, as a flexible polyurethane foam of this invention, a slab polyurethane foam is preferable. The slab polyurethane foam is a continuous material by discharging the mixed and stirred raw material (reaction mixed raw material) onto a belt conveyor, and while the belt conveyor moves, the raw material naturally foams and cures at normal temperature and atmospheric pressure. To be manufactured. Then, after hardening (curing) in a drying furnace, it is cut into a predetermined shape.

  Examples of the present invention will be specifically described below together with comparative examples. Using the components shown in Table 1 and Table 2 in accordance with the blending ratios in the same table, flexible polyurethane foams of Examples and Comparative Examples were produced by the one-shot method and the method for producing slab polyurethane foams.

  Polyol 1 shown in Tables 1 and 2 is product name: GP3000 (polyether polyol, propylene oxide adduct of glycerin starter, Mw = 3000, f = 3, OHV = 56.1), manufactured by Sanyo Chemical Industries, polyol 2 Is product name: N-2200 (polyester polyol, OHV = 60.5), manufactured by Nippon Polyurethane Industry Co., Ltd., polyol 3 is product name: F-3010 (polyester polyol, 3-methyl-1,5-pentanediol / adipic acid Copolymer, Mw = 3000, f = 3, OHV = 56.1), manufactured by Kuraray Co., Ltd., reactive amine catalyst 1 is dimethylethanolamine, manufactured by Air Products Co., Ltd., reactive amine catalyst 2 is product name: KL No. . 25 (N, N-dimethylaminohexanol), manufactured by Kao Corporation, non-reactive amine catalyst 1 is product name 33LV (triethylenediamine 33% dipropylene glycol solution), manufactured by Air Products Co., Ltd., non-reactive catalyst 2 is product name: KL No. 8 (N, N ″, N′-trimethylaminoethylpiperazine), manufactured by Kao Corporation, non-reactive catalyst 3 is a product name: KL No. 22 (N-ethylmorpholine), manufactured by Kao Corporation, metal catalyst is product name: MRH-110 (stannas octoate), manufactured by Johoku Chemical Industry Co., Ltd., foam stabilizer 1 is product name: SZ-1136 (polyalkylene-modified silicone) ), Manufactured by Nippon Unicar Co., Ltd., foam stabilizer 2 is product name: B-8324 (silicone foam stabilizer for ester), manufactured by Goldschmidt Co., Ltd., foam stabilizer 3 is product name: BJ-100 (nonionic surfactant). , Manufactured by Kao Corporation, reactive phosphite antioxidant is product name: CS-22 (tris (dipropylene glycol) phosphite), manufactured by GE Toshiba Silicone Co., Ltd., other antioxidant 1 is product name: I- 1135 (benzenepropanoic acid, 3,5-bis (1,1-methyl-ethyl) -4hydroxy-, C7-C9 side chain alkyl ester), Ciba Specialty Other antioxidants 2 manufactured by Chemicals Co., Ltd. are product names: JPP-13IN (bis (tridecyl) pentaerythritol diphosphite), Johoku Chemical Industry Co., Ltd., isocyanates are product names: Coronate T-80 (tolylene diisocyanate, 2 , 4-TDI isomer ratio 80%), manufactured by Nippon Polyurethane Industry Co., Ltd. Each example and each comparative example were in a good foamed state.

  Examples 1 to 3 are examples in which the polyol is a polyether polyol, Examples 4 to 5 are examples in which the polyol is a polyester polyol, and Example 6 is an example in which a polyether polyol and a polyester polyol are used in combination with the polyol. In Example 3, the reactive amine catalyst 2 was used, and in the other examples, the reactive amine catalyst 1 was used. In contrast, Comparative Example 1 is an example in which the same amount of other antioxidant 2 was used in place of the reactive phosphorous ester antioxidant in Example 1, and Comparative Example 2 was reactive phosphorous acid in Example 2. Example in which another antioxidant 2 was increased in the same amount in place of the ester antioxidant, Comparative Example 2A was an example in which a metal catalyst was further added to the formulation of Example 2, and Comparative Example 3 was a reactive amine in Example 3. Example in which the addition amount of the catalyst 2 was 0 parts by weight, Comparative Example 3A was an example in which the non-reactive amine catalyst 1 was increased by the same amount instead of the reactive amine catalyst 2 in Example 3, and Comparative Example 3B was in Example 3. Example in which the same amount of the non-reactive amine catalyst 2 was used instead of the reactive amine catalyst 2 in Comparative Example 4, and Comparative Example 4 used another antioxidant 2 in place of the reactive phosphite antioxidant in Example 4 Example 5 and Comparative Example 5 are reactive amine catalysts in Example 5. The amount of 1 is an example of the 0 part by weight.

  The density (JIS K 7222: 1999 compliant), hardness (JIS K 6400-2: 2004 D compliant), and elongation (JIS K 6400) were compared with the flexible polyurethane foams of Examples and Comparative Examples thus obtained. -5: 2004 compliant), tensile strength (JIS K 6400-5: 2004 compliant), and tear strength (JIS K 6400-5: 2004 compliant) were measured. The measurement results are shown in the lower column of Tables 1 and 2.

  Further, a 40 × 20 × 10 mm thick sample was cut out from the central part of the flexible polyurethane foams of the examples and comparative examples, and the NOx discoloration property, the NOx discoloration property after thermoforming, and the NOx discoloration property test after heat history were conducted as follows. It was done like that. The measurement results are as shown in the lower columns of Tables 1 and 2. Samples for NOx discoloration, NOx discoloration after thermoforming, and NOx discoloration test after thermal history were prepared.

In the NOx discoloration test, a sample was stored together with 5% NO ₂ gas (diluted with N ₂ ) in a NOx gas exposure device (product name: KG-120, manufactured by Fact Kei Co., Ltd.) and exposed to NO ₂ gas for 3 hours. The YI value before exposure and 1 day after the end of gas exposure was measured with a color difference meter (product name: SM color computer SM-T, manufactured by Suga Test Instruments Co., Ltd.), and the difference ΔYI value was used as the NOx discoloration measurement value. The NO ₂ concentration is 15 ppm, the test environment temperature is 30 ° C., and the humidity is 75% RH.

In the NOx discoloration test after thermoforming, the sample cut out as described above was sandwiched by a hot press machine heated to 200 ° C., pressed to a thickness of 3 mm (3/10 thickness before pressing), and maintained in that state for 60 seconds. Then, after releasing the heat press and leaving it for 1 day, the sample was exposed to NO ₂ gas for 3 hours under the same conditions as in the NOx discoloration test, and the heat press (thermoforming) was performed. ) Immediately after and one day after the end of gas exposure, the YI value was measured with a color difference meter (product name: SM color computer SM-T, manufactured by Suga Test Instruments Co., Ltd.), and the difference ΔYI value was measured as the NOx discoloration measurement value after thermoforming. did.

The NOx discoloration test after the heat history was carried out by storing the sample cut out as described above in a plastic bag, sealing the bag, storing the bag together in a 120 ° C. constant temperature layer, leaving it for 20 hours, and then leaving the bag from the constant temperature layer. After removing the sample from the bag and leaving it for 1 day, the sample was exposed to NO ₂ gas for 3 hours under the same conditions as in the NOx discoloration test, and immediately after removal from the bag and 1 day after the end of the gas exposure. The YI value was measured with a color difference meter (product name: SM color computer SM-T, manufactured by Suga Test Instruments Co., Ltd.), and the difference ΔYI value was taken as the NOx discoloration measurement value after thermal history.

  As shown in the measurement results of Tables 1 and 2, the flexible polyurethane foams of Examples 1 to 6 containing both a reactive amine catalyst and a reactive phosphite antioxidant and no metal catalyst were reacted. A flexible polyurethane foam of Comparative Examples 1, 2, 3 to 5 lacking at least one of a reactive amine catalyst and a reactive phosphite antioxidant, and both a reactive amine catalyst and a reactive phosphite antioxidant In addition, in comparison with the flexible polyurethane foam of Comparative Example 2A containing a metal catalyst, the ΔYI value is small for NOx discoloration, NOx discoloration after thermoforming, and NOx discoloration after heat history. It was excellent.

  Thus, the flexible polyurethane foam of the present invention is excellent in discoloration resistance after thermoforming, and is suitable for clothing that is shaped by thermoforming (hot pressing).

Claims (1)

In a flexible polyurethane foam obtained by reacting a polyol and an isocyanate in the presence of a blowing agent, a catalyst and an antioxidant,
The isocyanate consists only of tolylene diisocyanate,
The catalyst consists only of an amine catalyst containing a reactive amine catalyst,
The flexible polyurethane foam, wherein the antioxidant includes a reactive phosphite, and the reactive phosphite is tris (dipropylene glycol) phosphite .