JPS6244582B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyurethane composition with excellent heat resistance and weather resistance. Polyurethanes are generally unstable to light, heat, and atmospheric components. This instability stems from the structure of polyurethane, resulting in strong discoloration and a drastic reduction in mechanical properties, severely limiting its applications. For this reason, attempts have been made to stabilize polyurethane by adding antioxidants such as aliphatic polyamines and phenols; ultraviolet absorbers such as benzophenone and benzotriazole. However, these conventional stabilization methods have not yet produced sufficiently satisfactory effects. In particular, as a compound containing an active hydrogen group, having an unsaturated bond,
For example, when using a diene polymer, the stabilizing effect was still insufficient. Furthermore, with conventional improvement techniques, (1) staining (colors the base material), (2) deterioration may be accelerated depending on the combination of stabilizers, and (3) amine-based compounds, etc. There were drawbacks such as some substances being toxic. The present inventors have conducted intensive research to solve the above-mentioned drawbacks, and as a result, have discovered that an excellent stabilizing effect can be obtained when a specific additive is used in combination, and have completed the present invention. That is, the present invention provides a polyurethane comprising a polyisocyanate compound and an active hydrogen group-containing compound, () a benzotriazole ultraviolet absorber,
() Hindered phenolic antioxidant, ()
Hydroquinones represented by the following general formula (A) or aromatic nitro compounds represented by the general formula (B) (Here, R ₁ and R ₂ are hydrogen or an alkyl group.) (Here, R ₃ is hydrogen, a methyl group, or a hydroxyl group, and n is an integer of 1 to 3). Generally, polyurethane is produced by reacting a polyisocyanate compound and usually a polyhydroxy-containing compound, and is an elastic material.
It is used in many ways, including synthetic leather and paint. Examples of the polyisocyanate compound used in the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, xylylene diisocyanate, cyclohexane phenylene diisocyanate, chlorophenylene diisocyanate, naphthalene-1,5- Diisocyanate, xylylene
2,2'-diisocyanate, isopropylbenzene-2,4-diisocyanate, addition reaction product of polypropylene glycol or triol with tolylene diisocyanate, trimethylolpropane 1
An example is an addition reaction product of 3 moles of tolylene diisocyanate and 3 moles of tolylene diisocyanate. Next, examples of active hydrogen group-containing compounds include low-molecular polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, glycerin, trimethylolpropane, 1,2,6-hexanetriol, and pentaerythritol; Addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to amine compounds such as 4'-methylene-bis-2-chloroaniline and 4,4'-methylene-bis-2-ethylaniline, or to low-molecular polyols or amine compounds. Examples include polyether polyols such as propylene oxy adducts of bisphenols. Furthermore, it is a condensation polymer of polyhydric alcohols such as ethylene glycol, propylene glycol, and 1,4-butanediol and polybasic acids such as phthalic acid, maleic acid, malonic acid, succinic acid, adipic acid, and terephthalic acid, and Polyester polyols, acrylic polyols, castor oil, tall oil, etc., each having a hydroxyl group can also be mentioned. There are also liquid rubbers that have active hydrogen groups such as hydroxyl groups, amino groups, imino groups, carboxyl groups, and mercapto groups at the molecular ends. These liquid rubbers have a number average molecular weight of 500
~25,000 diene polymers and copolymers with 4 to 12 carbon atoms, as well as these diene monomers and 2 to 22 carbon atoms.
There are copolymers with α-olefinic addition polymerizable monomers. Specific examples include polybutadiene homopolymer, polyisoprene homopolymer, butadiene-isoprene copolymer, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhexyl acrylate copolymer, butadiene-n-octadecyl acrylate copolymer, and the like. A reaction promoting catalyst can also be added to the polyurethane composition of the present invention in order to lower the reaction temperature and shorten the reaction time. Specific examples thereof include organometallic compounds such as dibutyltin dilaurate, tin octylate, lead octylate, and manganese octylate; amine compounds such as triethylenediamine and tri-n-butylamine; and salts thereof. Furthermore, reinforcing agents, fillers, softeners, colorants, antistatic agents, etc. can be added as auxiliary ingredients. Examples of reinforcing agents or fillers include carbon black, calcium carbonate, finely divided silicic acid, clay, organic powder, organic fiber, and inorganic fiber.
These may be used singly or in combination of two or more which do not promote deterioration of the polyurethane composition.
The amount of these compounds should be 500 parts by weight or less per 100 parts by weight of the composition. If it exceeds 500 parts by weight, the quality of the composition will deteriorate, which is not preferable. Further, softeners include process oil, asphalt, petroleum resin, polybutene, etc., and are similarly used in an amount of 500 parts by weight or less per 100 parts by weight of the composition. The polyurethane composition of the present invention is made by adding and mixing () a benzotriazole ultraviolet absorber, () a hindered phenol antioxidant, and () hydroquinones or aromatic nitro compounds into these polyurethanes. . Here, () What is benzotriazole ultraviolet absorber? General formula (1) General formula (2) (In the above general formulas (1) and (2), X is hydrogen, halogen, R ₁ , R ₂ , R ₃ are hydrogen, halogen, alkyl group, hydroxyl group, alkoxy group.) Specifically, 2(2'-hydroxy-3',5'-di-t-butylphenyl)5-chlorobenzotriazole, 2(2'-hydroxy-5'-
methylphenyl)benzotriazole, 2(2′-
hydroxy-3',5'-di-t-amyl phenyl)
Benzotriazole, 2(2'-hydroxy-3',
5'-di-t-butylphenyl)benzotriazole, 2(2'-hydroxy-3'-t-butyl-5'-
methylphenyl)benzotriazole, 2(2′-
Hydroxy-3',5'-diisoamyl phenyl)benzotriazole, 2(2',4'-dihydroxyphenyl)5-chlorobenzotriazole, 2
Examples include (2',4'-dihydroxyphenyl)benzotriazole and 2(2'-hydroxy-4'-octyloxyphenyl)benzotriazole. Also, what is () hindered phenolic antioxidant? General formula (3) General formula (4) General formula (5) General formula (6) (In the above general formulas (3) to (6), R ₄ is hydrogen or an alkyl group, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ is hydrogen or an alkyl group, and X is carbon, nitrogen, an alkyl group, or an alkylene group. group, alkyleneamine group, Y, Y' are alkylene group, alkylidene group, sulfur, n is 1 to 4, m is 1
~5, and tBu is a t-butyl group. ), and preferred as the compound of the above general formula (3) is the compound represented by the formula

It is a dialkyl-substituted hydroquinone represented by the formula: (R ₅ and R ₆ are alkyl groups). Specific compounds include 2,5-di-t-amylhydroquinone, 2,5-di-t-
Butyl hydroquinone, 2-t-butyl hydroquinone monomethyl ether, 5-t-butyl hydroquinone monomethyl ether, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyphenylpropionate)] methane, N, N ，
N-Tris [β-3,5-di-t-butyl-4-
hydroxyphenyl)-propionyl]-tripropanolamine, 1,3,5-trimethyl-
2,4,6-tris(3,5-di-t-butyl-
4-Hydroxybenzyl)benzene, 2,2'-methylene-bis(6-t-butyl-4-methylphenol), 4,4'-butylidenebis(6-t-butyl-3-methylphenol)2,6- Di-stearyl-4-methylphenol, n-octadecyl-β-(4'-hydroxy-3',5'-di-t-butylphenylpropionate), 4,4'-thiobis(6-t- butyl-3-methylphenol)
Examples include 4,4'-methylene-bis(2,6-di-t-butylphenol). Next, () What are hydroquinones or aromatic nitro compounds? General formula (In the above general formulas (A) and (B), R ₁ and R ₂ are hydrogen,
It is an alkyl group, R ₃ is hydrogen, a methyl group, or a hydroxyl group, and n is an integer of 1 to 3. ), and specific examples include the following: That is, the compounds of general formula (A) include hydroquinone, hydroquinone monomethyl ether, hydroquinone monoethyl ether,
Examples include hydroquinone diethyl ether, hydroquinone dimethyl ether, and hydroquinone-n-butyl ether. Examples of the compound of general formula (B) include 2,4-dinitrotoluene, dinitrobenzene, trinitrotoluene, trinitrobenzene, nitrophenol, and trinitrophenol. These compounds are generally used as polymerization inhibitors such as styrene and methyl acrylate, but no effect is observed even if they are simply blended with polyurethane. However, when used in combination with the additives () and () of the present invention,
A superior synergistic effect is observed compared to the effect obtained when using either alone or in combination. This was first discovered through experiments conducted by the present inventors. Next, the amount of these additives to be added is not particularly limited, and is arbitrarily determined depending on the conditions under which the polyurethane composition is used. Usually each additive
It ranges from 0.01 to 5% by weight, preferably from 0.05 to 2% by weight. If the amount added is less than this range, it is difficult to recognize the stabilizing effect, and if it is more than this range, the physical properties such as strength and elongation of the resulting product will not only decrease, but also may cause initial discoloration. So I don't like it. Note that the amount of each additive added does not necessarily have to be equal, and is arbitrarily determined depending on the type of polyisocyanate compound and active hydrogen group-containing compound used as raw materials. Similarly, the most suitable combination of specific compounds among each additive may be selected as appropriate. The polyurethane composition thus obtained has significantly reduced yellowing and deterioration caused by heat, light, or atmospheric components. Therefore, the composition of the present invention can be used for elastic molded bodies, paints, adhesives, pressure-sensitive adhesives,
It can be applied to applications that were previously limited due to lack of stability in fields such as synthetic leather and foam, significantly expanding the range of their use. The present invention will be explained below with reference to Examples and Comparative Examples. Examples, Comparative Examples Liquid polybutadiene containing terminal hydroxyl groups (number average molecular weight 2800, viscosity 50 poise (30°C), hydroxyl group content
0.83meq/g) to 100 parts by weight, add the prescribed amount (unit: parts by weight) of the stabilizer shown in Table 1, and heat at 70 to 120°C.
The stabilizer was dissolved by heating and stirring for 10 to 20 minutes. Next, 38.3 parts by weight of 4,4'-diphenylmethane diisocyanate liquid modified prepolymer (equal amounts of the above-mentioned terminal hydroxyl group-containing liquid polybutadiene and polyoxypropylene glycol (molecular weight 2000), NCO group content: 9% by weight) 0.03 parts by weight of di-n-butyltin dilaurate was added and thoroughly mixed and stirred. After degassing this mixture, it was poured into a mold with a thickness of 1 mm, compressed at 70°C for 60 minutes, and a cured product sheet (100 mm
x 100 mm x 1 mm) was obtained. The obtained sheet was subjected to a heat treatment test in a gear oven at 70°C for 7 days. At the same time, a 500-hour weather test was conducted using a carbon arc weather meter (rain cycle: 120 minutes, rain duration: 18 minutes). The degree of yellowing of the sample after the test was observed and the results are shown in Table 1. The test machine used in the experiment is as follows. (1) Gear oven: Gear type aging tester manufactured by Uejima Seisakusho Co., Ltd. (2) Carbon arc weather meter…Du-Cycle Sunshine Super Long Life Weather Meter manufactured by Suga Test Instruments Co., Ltd. WEL-SUN-
D.C. Moreover, the yellowing degree evaluation in the heat treatment test and the weathering test is as follows. 1...almost colorless 2...slight yellow 3...slight yellow 4...slight yellow 5...yellow 6...slightly brown 7...brown

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Claims (1)

[Claims] 1 A polyurethane consisting of a polyisocyanate compound and an active hydrogen group-containing compound, () a benzotriazole ultraviolet absorber, () a hindered phenol antioxidant, () general formula (A) (Here, R ₁ and R ₂ are hydrogen or an alkyl group.) Hydroquinones or general formula (B) (Here, R ₂ is hydrogen, methyl group, or hydroxyl group, and n is an integer of 1 to 3.) A polyurethane composition prepared by adding and mixing an aromatic nitro compound represented by the following. 2 The active hydrogen group-containing compound has a hydroxyl group, an amino group,
The polyurethane composition according to claim 1, which is a liquid diene polymer or copolymer containing one type of carboxyl group. 3 Hindered phenolic antioxidant has the general formula The polyurethane composition according to claim 1 or 2, which is a dialkyl-substituted hydroquinone represented by the formula (wherein R ₅ and R ₆ are alkyl groups).