JPH049806B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a polyurethane composition that is flexible and tough, and has excellent heat resistance, solvent resistance, weather resistance, discoloration resistance, and the like. [Prior Art] Polyurethane compositions have been used in a wide range of applications such as paints, various molded products, and artificial leather due to their excellent properties. For example, silver-covered artificial leather made by coating a fibrous base material with a polyurethane composition is preferably used because of its soft and tough properties. However, we have not been able to obtain sufficient heat resistance to withstand ironing, solvent resistance to withstand dry cleaning and washing, discoloration resistance to withstand long-term use, and durability (stability against light, heat, oxygen, etc.). This is the actual situation. Various methods have been proposed to improve these drawbacks, including (a) using polyurethane with a specific structure, (b) adding various stabilizers, and (c) combining (a) and (b). However, it has been insufficient to satisfy the above characteristics in a well-balanced manner. [Problems to be Solved by the Invention] An object of the present invention is to provide an improved polyurethane composition that is flexible and tough, and satisfies properties such as heat resistance, solvent resistance, discoloration resistance, and durability in a well-balanced manner. More specifically, for example, in the case of silver-finished artificial leather for clothing, polyurethane-based materials are used that are flexible and tough, can withstand dry cleaning and ironing, and have little discoloration or deterioration when worn for long periods of time. An object of the present invention is to provide a composition. [Means for Solving the Problems] The polyurethane composition of the present invention is produced by reacting a polymeric diol with a molecular weight of 500 to 5,000 having hydroxyl groups at both ends with 1.5 to 6.0 molar equivalents of an organic diisocyanate to the polymeric diol. and a polyurethane (A) obtained by further reacting with a chain extender and having a nitrogen content based on isocyanate groups of 2 to 8% by weight and an OH value of 20 or less; (R is a divalent hydrocarbon residue having 2 or 3 carbon atoms.) The polyurethane (A) and the trifunctional isocyanate compound (B) solid content weight ratio of 100:5~50
This is a polyurethane composition characterized by the following. [Function] That is, in the present invention, the excellent properties described above can be obtained by crosslinking the polyurethane elastomer with a specific trifunctional isocyanate compound. Furthermore, by further bonding a specific hindered amine compound, permanent color fastness and weather resistance can be imparted. The polyurethane elastomer used in the present invention is a polymer obtained by reacting a polymeric diol, an organic diisocyanate, and a chain extender. Examples of polymeric diols include polyether glycol, polyester glycol, and polyether ester glycol, which have hydroxyl groups at both ends and have a molecular weight of 500 or more, preferably 1,000 to 5,000. These include ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, polycaprolactone glycol, polyethylene adipate, polybutylene adipate, polytetramethylene adipate, etc. alone or in mixtures. Examples of the organic isocyanate include diphenylmethane-4,4'-diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and mixtures thereof. The chain extender is a compound having two functional groups that react with the organic diisocyanate as shown in the above example, and the glycol chain extender includes ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, etc. be. Examples of the diamine chain extender include 4,4'-diaminodiphenylmethane, tolylene diamine, 4,4'-diaminodicyclohexylmethane, and mixtures thereof. The object of the present invention is flexibility, high strength, and
In order to satisfy physical properties such as heat resistance, solvent resistance, and weather resistance in a well-balanced manner, the amount of organic diisoanate relative to the polymer diol should be 1.5 to 6.0 molar equivalents, and the nitrogen content based on isocyanate groups should be 2 to 8% by weight.
is preferred. A high molecular weight polyurethane elastomer with an OH value of 20 or less, preferably 10 or less is desirable, and it is important to select the most suitable one depending on the desired properties. The trifunctional isocyanate compound used in the present invention is represented by the above general formula, and is 2,6-
Diisocyanate caproic acid - β-isocyanate ethyl ester, 2,6-diisocyanate caproic acid - γ-isocyanate propyl ester, 2,6-diisocyanate caproic acid -2-
Methyl-β-isocyanate ethyl ester and the like. All of these can be produced by a known method of phosgenating an ester of lysine and an amino alcohol. The mixing ratio of the trifunctional isocyanate compound to the polyurethane elastomer is determined depending on the desired properties, but is preferably 5 to 50%, particularly preferably 10 to 20% by weight. Conventionally, as a crosslinking agent, (a) a triadduct of trimethylolpropane with tolylene diisocyanate and (b) a triadduct of hexamethylene diisocyanate with trimethylolpropane are often used. When (a) is used, a tough but hard film is obtained. If the amount used is increased in order to improve the properties, the material becomes harder and harder, making it impossible to simultaneously satisfy various properties such as flexibility, toughness, heat resistance, and solvent resistance. In the case of (b), it is used as a non-yellowing type crosslinking agent, but it has drawbacks such as being relatively flexible but slow in reaction, and having a rough crosslinked structure and inferior in the above properties. However, the trifunctional isocyanate according to the present invention performs a crosslinking reaction quickly and a dense crosslinked structure is obtained, and is excellent in the above-mentioned properties.Since it is a non-yellowing type, it is excellent in discoloration resistance and light deterioration resistance. Furthermore, the polyurethane composition of the present invention can further significantly improve discoloration resistance and light resistance by bonding a specific hindered amine to the polyurethane molecular chain. Methods for introducing a hindered amine include (a) a method in which it is added and mixed during the reaction of a polyol and an isocyanate during the synthesis of a polyurethane elastomer, or a method in which it is added and mixed when a terminal isocyanate prepolymer and a chain extender are reacted; (b) A method of adding and mixing a polyurethane elastomer and a trifunctional isocyanate during a crosslinking reaction,
Alternatively, a method may be used in which a trifunctional isocyanate and a hindered amine are mixed and reacted, and then crosslinked with a polyurethane elastomer. In the case of (a), there are drawbacks such as the difficulty in increasing the molecular weight of the polyurethane and the fact that the polyurethane elastomer bonded with hindered amine is in a liquid state and easily decomposes when left for a long period of time. In the case of (b), the above-mentioned concerns are avoided and it is preferable because the ingredients are added, mixed, and reacted during the preparation of the paint. The amount of hindered amine added is not particularly limited, but is preferably in the range of 0.1 to 5 parts, particularly preferably 0.1 to 2 parts, based on 100 parts of the polyurethane elastomer. Additionally, hindered amines are effective in small doses;
Both methods (a) and (b) above have remarkable effects without impairing the original properties of polyurethane, and are not simply mixed.
Since it is chemically bonded to polyurethane crosslinked with a trifunctional isocyanate compound, it is not extracted and removed by bleeding out or solvent treatment, and its effect is permanent. Specific examples of hindered amine compounds used in the present invention include 2,2,6,6-tetramethyl-4-hydroxypiperidine, 2,2,6,6-
Tetramethyl-4-methyl-4-hydroxypiperidine, 2,2,6,6-tetramethyl-4-ethyl-4-hydroxypiperidine, 2,2,6,
6-tetramethyl-4-phenyl-4-hydroxypiperidine, 2,2,6,6-tetramethyl-
4-aminopiperidine, 2,2,6-trimethyl-6-ethyl-4-hydroxypiperidine, 2,
2,6-trimethyl-6-ethyl-4-aminopiperidine, 2,2-dimethyl-6,6-diethyl-4-hydroxypiperidine, 2,2-dimethyl-6,6-diethyl-4-aminopiperidine,
2,2-dimethyl-4-hydroxy-1-azaspiro[5,5]undecane, and 2,2-dimethyl-4-amino-1-azaspiro[5,5]undecane, or a mixture thereof. 1-benzyl-2,2,6,6-tetramethyl-4-hydroxypiperidine, 1-benzyl-2,2,
6,6-tetramethyl-4-ethyl-4-hydroxypiperidine, 1-benzyl-2,2,6,6
-Tetramethyl-4-phenyl-4-hydroxypiperidine, 1-benzyl-2,2,6,6-tetramethyl-4-aminopiperidine, 1-benzyl-2,2,6-trimethyl-6-ethyl-4 −
Hydroxypiperidine, 1-benzyl-2,2,
6-trimethyl-6-ethyl-4-aminopiperidine, 1-benzyl-2,2-dimethyl-6,6
-diethyl-4-hydroxypiperidine, 1-benzyl-2,2-dimethyl-6,6-diethyl-
4-aminopiperidine, 1-benzyl-2,2-
dimethyl-4-hydroxy-1-azaspiro[5,5]undecane, and -1benzyl-2,
2-dimethyl-4-amino-1-azaspiro[5,5]undecane or a mixture thereof. 1-methyl-2,2,6,6-tetramethyl-
4-hydroxypiperidine, 1-methyl-2,
2,6,6-tetramethyl-4-ethyl-4-hydroxypiperidine, 1-methyl-2,2,6,
6-tetramethyl-4-phenyl-4-hydroxypiperidine, 1-methyl-2,2,6,6-tetramethyl-4-aminopiperidine, 1-methyl-2,2,6-trimethyl-6-ethyl- 4-hydroxypiperidine, 1-methyl-2,2,6-
Trimethyl-6-ethyl-4-aminopiperidine, 1-methyl-2,2-dimethyl-6,6-diethyl-4-hydroxypiperidine, 1-methyl-2,2-dimethyl-6,6-diethyl-4- Aminopiperidine, 1-methyl-2,2-dimethyl-4-hydroxy-1-azasubiro[5,5]undecane, 1-methyl-2,2-dimethyl-4-
Amino-1-azaspiro[5,5]undecane or mixtures thereof. More preferably,
2,2,6,6-tetramethyl-4-hydroxypiperidine, 2,2,6,6-tetramethyl-4
-Aminopiperidine, 1-benzyl-2,2,
6,6-tetramethyl-4-hydroxypiperidine, 1-benzyl-2,2,6,6-tetramethyl-4-aminopiperidine, 1-methyl-2,
2,6,6-tetramethyl-4-hydroxypiperidine, 1-methyl-2,2,6,6-tetramethyl-4-aminopiperidine or a mixture thereof. More preferably 2,2,6,6-tetramethyl-4-hydroxypiperidine, 2,2,
6,6-tetramethyl-4-aminopiperidine,
1-methyl-2,2,6,6-tetramethyl-4
Hydroxypiperidine, 1-methyl-2,2,
6,6-tetramethyl-4aminopiperidine or a mixture thereof. In addition to the above compounds, the hindered amine compound that can be used in the present invention is such that hydrogen bonded to the oxygen atom or nitrogen atom of the amino group, hydroxyl group, and monoalkylamino group of the substituent represented by X is -(R ₃ O) _o −H or −(COR ₄ COOR ₅ O) _n
-H may also be substituted. In the former case, R ₃ is a lower alkylene group and n is 1
Represents an integer between ~50. The lower alkylene group has 2 to 14 carbon atoms. This compound is obtained by reacting the original hindered amine compound with R ₃ O (alkylene oxide). Specific examples of R ₃ O (alkylene oxide) include ethylene oxide,
Propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, epichlorohydrin, etc., and mixtures thereof. In the latter case, R ₄ is an organic dicarboxylic acid residue, R ₅
represents an organic diol residue, and m represents an integer of 1 to 15. The organic dicarboxylic acid preferably has 2 to 12 carbon atoms, and specifically includes succinic acid, adipic acid,
Examples include azelaic acid, sebacic acid, phthalic acid, isophthalic acid, anhydrides thereof, and mixtures thereof. Organic diol has 2 or more carbon atoms
8 is preferred, and specific examples include ethylene glycol, propylene glycol, butylene glycol, hexane glycol, octane glycol, diethylene glycol, triethylene glycol, etc., and mixtures thereof. The above-mentioned hindered amine compounds are, for example,
It is synthesized according to the method described in Publication No. 53-1294 and its cited documents. The compositions of the present invention include other elastomeric polymers, pigments,
Dyes, fillers, stabilizers, etc. can be mixed and used as required. The composition of the present invention can be applied to paints, adhesives, artificial leather,
Can be used in a wide variety of molded products. In particular, when used as a coating agent and/or impregnating agent for silvered artificial leather, its characteristics can be maximized. The fibrous substrate may be a non-woven fabric, a woven fabric, a knitted fabric, or a laminated or sandwiched fabric made of ultra-fine fibers and ultra-fine fiber bundles formed from natural and synthetic fibers of normal fineness, sea-island type fibers, peelable and split type fibers, etc. A polymer elastomer solution and/or dispersion liquid is applied as necessary. At least one side of these fibrous substrates may be fluffed by napping, buffing, or the like.
It is preferable that such a fibrous material is colored, but if it is uncolored, it may be colored after imparting a silver surface. It is desirable that this fluff layer forms a silver surface. Furthermore, the finer the denier of the fibers in the fluff layer, and the higher the fluff density, the thinner the grain layer can be, resulting in a softer texture and superior appearance quality. Also,
It is preferable that the surface of the fibrous substrate is made of microfibers and/or bundles thereof densely intertwined, since its smoothness allows the coating layer of the high molecular weight polymer to be made thinner, thereby reducing the rubbery feel. In addition, methods for obtaining silver-finished artificial leather include a method of applying the composition of the present invention to a fibrous substrate using a gravure roll, a reverse roll coater, a knife coater, etc., heating and curing it, adding texture, and finishing the surface. A surface resin is applied to a textured release paper, and after drying and solidification, the composition of the present invention is applied thereon, and a fibrous substrate is bonded to the surface while it is dry and still sticky, and both are peeled off after being heated and cured. It is possible to obtain the amount by [Effect of the invention] The characteristics of the polyurethane composition of the present invention and the characteristics of products using the same are that it is flexible and tough, and has a good balance of various properties such as heat resistance, solvent resistance, weather resistance, and discoloration resistance. It can satisfy you well. For example, when used in silvered artificial leather, it exhibits characteristics such as soft texture, high grain surface strength, excellent ironing and dry cleaning properties (especially change in appearance), and little discoloration or deterioration due to long-term use. . In addition, characteristics such as bleed-out of various additives in the film during long-term storage, migration of dye from the dyed base material to the film, and bleed-out are extremely low. Furthermore, in the manufacturing method of silver-covered artificial leather, a surface layer is formed on release paper, an adhesive layer is applied on top of the surface layer, and the base material is laminated.
Taking advantage of the flexible and highly crosslinkable characteristics of the crosslinking agent according to the present invention, it can be used extensively in adhesive layers, and a portion thereof can be transferred to the surface layer to improve solvent resistance. Hereinafter, embodiments of the present invention will be shown, but the present invention is not limited thereto. Unless otherwise indicated, percentages and parts are by weight. Example 1 Polyurethane elastomer (OH value = 4) consisting of polycaprolactone glycol, diphenylmethane-4,4'-diisocyanate and butylene glycol
Add 15 parts of 2,6-diisocyanate caproic acid β-isocyanate ethyl ester as a trifunctional isocyanate compound to 15 parts of 2,6-diisocyanate caproic acid β-isocyanate ethyl ester per 100 parts of polyurethane solid content to a 45% solution of MEK/TOL = 2/1 mixture with nitrogen content of 5.25%). A composition solution was prepared. These dry membranes with a thickness of approximately 75 μm were prepared and evaluated on various items. The evaluation method is as follows. Light resistance was evaluated visually using a fade meter after 50 hours of irradiation (at 63°C) and rated the discoloration on a five-point scale (5 being the best).The strength retention rate was calculated using the following formula by measuring the strength before and after irradiation.Strength retention rate (%) = Intensity after irradiation / Intensity before irradiation ×
100 Hydrolysis resistance was determined by the following formula based on the strength retention rate when left for 4 weeks at a temperature of 70°C and a humidity of 90%. Strength retention rate (%) = Strength after hydrolysis / Strength before hydrolysis × 100 Per-Clene swelling resistance is calculated by calculating the area swelling rate when immersed in dry cleaning liquid (Per-Cene type) at 50℃ for 2 hours using the following formula. I asked for it. Area swelling rate (%) = Area after immersion / Area before immersion ×
100 Example 2 As a trifunctional isocyanate compound, 2,6-diisocyanate caproic acid-γ having the same general formula
A dry membrane was obtained in the same manner as in Example 1 except that -isocyanate propyl ester was used. Comparative Example 1 A dry film was obtained in the same manner as in Example 1, except that a 3-mol adduct of trimethylolpropane and tolylene diisocyanate having different general formulas was used as the trifunctional isocyanate. Comparative Example 2 A dry film was obtained in the same manner as in Example 1, except that a 3-mol adduct of hexamethylene diisocyanate of trimethylolpropane having a different general formula was used as the trifunctional isocyanate. Examples 3 and 4, Comparative Examples 3 and 4 The island component is 70 parts of polyester and the sea component is 30 parts of polystyrene, number of islands is 16, single yarn denier is 3.5
I made needle punched felt using 51mm denier. Next, this was shrunk in boiling water and dried, then impregnated with a 10% mixed dispersion consisting of 4 parts of non-yellowing type polyurethane and 6 parts of polyvinyl alcohol, and dried. Next, the polystyrene was extracted and removed in triclene, and after drying, it was impregnated with a 12% polyvinyl alcohol solution, and after drying, it was impregnated with a 12% DMF solution of polycaprolactone-based polyurethane.
Wet coagulation was performed in water, followed by removal of DMF and polyvinyl alcohol in hot water, followed by drying. Slice this into half thickness, #100 on both sides.
Buffed with sandpaper, then finished buffed with #150 sandpaper, dyed black with a jet dyeing machine, thickness 0.65mm, basis weight 210g/m ² ,
A dyed fibrous substrate with naps on both sides having an apparent density of 0.323 g/cm ³ was obtained. Next, 10% of polycaprolactone polyurethane
% solution was applied to a release paper with a kerf adjustment drawing using a knife coater so that the dry film had a thickness of 7μ, and after drying, 20% of the composition solutions of Examples 1 and 2 and Comparative Examples 1 and 2 were applied to the dry film. After coating to a thickness of 22μ and removing a portion of the solvent, it was bonded and fixed to the above-mentioned fibrous substrate by pressure bonding, and after drying and curing, it was peeled off to obtain silver-covered artificial leather. Comparative Examples 3 and 4). This product was evaluated by the following method. Texture: Using a strip-shaped piece with a width of 2 cm,
It was determined by the cantilever method (45° tilt). Washing resistance: The blouson was sewn and subjected to normal dry cleaning (dry cleaning with Perclean) 5 times, and the appearance of wrinkles on the surface was visually judged and divided into 5 grades. 5 indicates that wrinkles are least likely to form and are good. The evaluation targeted the interlining bonded area and the area without interlining. Silver surface strength; light resistance test (temperature 63 with fade meter)
°C, 50 hours irradiation), hydrolysis resistance test (temperature 70
℃ and 90% humidity for 1 month)) Using a flexometer (JISK6545-1970), the state of surface cracks after 200,000 hours of bending was visually determined and divided into 5 grades. 5 is the best condition with no cracks. Color transfer: Layer white artificial leather with silver (target piece) and colored artificial leather with silver (test piece) and heat at 70°C x 70°C.
%, and color transfer after being left for 24 hours under conditions of 1 Kg/cm ² was visually evaluated on a five-point scale. 5 is the best. Solvent resistance: A cloth was impregnated with toluene and the degree of change in the silver surface when gently wiped was visually evaluated on a five-point scale. 5 is the best. It can be seen that the silvered artificial leather using the composition of the present invention is flexible and has excellent washing resistance and grain surface strength. In addition, both color transfer and solvent resistance were rated 5 for the products of the present invention (Examples 3 and 4), while the comparative products were 3. Examples 5 to 7, Comparative Examples 5 to 7 The compositions of Example 1 and Comparative Example 1 were prepared in the same manner as in Example 5 using various mixing ratios of polyurethane elastomer and trifunctional isocyanate. Silver-finished artificial leather was obtained. The results of evaluation using the method shown in Example 5 are shown in Table 3. The composition of the present invention is flexible and has good washing resistance even when the amount of trifunctional isocyanate added is changed.

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Claims (1)

[Scope of Claims] 1. A polymer diol having a molecular weight of 500 to 5,000 having hydroxyl groups at both ends, and an organic diisocyanate in an amount of 1.5 to 6.0 molar equivalents reacted with the polymer diol, and further reacted with a chain extender. and
A polyurethane (A) with a nitrogen content of 2 to 8% by weight based on isocyanate groups and an OH value of 20 or less, and a general formula (R is a divalent hydrocarbon residue having 2 or 3 carbon atoms.) The polyurethane (A) and the trifunctional isocyanate compound (B) solid content weight ratio of 100:5~50
A polyurethane composition characterized by: 2. The polyurethane composition according to claim 1, wherein the polymeric diol is polycaprolactone. 3. The polyurethane composition according to claim 1 or 2, wherein the organic diisocyanate is of a non-yellowing type.