JP2013108196A - Synthetic leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synthetic leather that is excellent in balance of physical properties such as perspiration resistance and flexibility, does not cause cracking and creasing during storage, does not cause a rough feeling and a sticky feeling, and is capable of being used as an automobile sheet and an interior material.SOLUTION: The synthetic leather is formed from a polyurethane resin including a reaction product of a polycarbonate diol, an organic diisocyanate and a chain extender. The polycarbonate diol includes a repeating unit represented by a formula (A) and a terminal hydroxyl group. 60-100 mol% of the repeating unit represented by the formula (A) is a repeating unit represented by 1,5-pentane diol carbonate B or 1,6-hexane diol carbonate C. The ratio of the repeating unit B to the repeating unit of C is from 90:10 to 10:90 (molar ratio). The polycarbonate diol has a number average molecular weight of 800-3500 and a primary terminal OH ratio of 95-99.5%.

Description

  The present invention relates to a synthetic leather made of a polyurethane resin.

  Conventional synthetic leather is obtained by applying a polyurethane resin solution polymerized using a polyether polyol such as polypropylene glycol or polytetramethylene glycol to a fibrous base material or a film-forming plate and coagulating it in water. is there. Although these synthetic leathers are excellent in flexibility, they have a problem in durability because they are easily decomposed by components such as sweat. Further, there is a synthetic leather obtained by coagulation using a polyurethane resin solution polymerized using a polyester polyol obtained by reacting a hydroxy compound and a dibasic acid. This synthetic leather has a problem in hydrolysis resistance.

  In order to solve these problems, for example, Patent Document 1 uses a polyurene resin polymerized using a polycarbonate diol. For example, a urethane composition comprising a polyurethane comprising a polycarbonate diol, an organic isocyanate and a low molecular diol and a polyurethane comprising a polyester diol, an organic diisocyanate and a low molecular diol is contained in and / or on the fiber base. Or the porous sheet-like material joined is disclosed.

  Patent Document 2 discloses a porous sheet material obtained by a wet film-forming method by applying a polyurethane resin solution comprising a polymer diol, an organic isocyanate, and optionally a chain extender to a substrate, and the polymer diol is a polycarbonate diol. And a polyester diol, and the polycarbonate diol is composed of one or more of 1,4-butanediol and other alkanediols having 4 to 6 carbon atoms, and the diol is based on the total number of moles of the diol. A porous sheet comprising 50 to 90 mol% of 1,4-butanediol, a copolymerized polycarbonate diol having a number average molecular weight of 500 to 5000, and a coagulation value of a polyurethane resin of 7 to 14 A material is disclosed.

  Patent Document 3 discloses that an aliphatic oligocarbonate diol obtained by transesterification of an aliphatic diol and a dialkyl carbonate and a ring-opening addition polymerization of a cyclic ester compound using a compound having an active hydrogen group as an initiator. A synthetic leather surface coating layer using a polyurethane resin comprising a polyester polycarbonate diol, a polyisocyanate, and a chain extender obtained by a transesterification reaction with a polyester polyol is disclosed.

  Patent Document 4 includes a polycarbonate diol (a1) composed of an alkanediol having 4 to 6 carbon atoms and a polycarbonate diol (a2) composed of an alkanediol having 7 to 12 carbon atoms. Both are copolymer polycarbonate diols, and a polymer diol, an organic isocyanate, and a chain extender in which the percentage by weight of (a1) with respect to the total weight of (a1) and (a2) is 10% to 80% are reacted. A porous sheet material obtained by wet coagulation is disclosed.

  Furthermore, in Patent Document 5, in the surface layer-forming composition for a fiber laminate composed of a main agent and a curing agent, the main agent is a polycarbonate diol obtained from 1,6-hexanediol and a low molecular carbonate, and the curing agent Is a hexamethylene diisocyanate modified polyisocyanate (B1) having a number average molecular weight of 350 to 500 and an average functional group number (f) of 2 ≦ f <3, and isocyanurate modified polyisocyanate (B2) of hexamethylene diisocyanate having f ≧ 3 (B1) :( B2) = 50: 50 to 95: 5 (weight ratio), and an organic solvent is not contained in both the main agent and the curing agent. A synthetic leather comprising a surface layer formed from a surface layer material-forming composition and a fiber fabric is disclosed.

  However, although the synthetic leather disclosed in these documents has hydrolysis resistance, sweat resistance is not sufficient in applications where high durability is required such as automobile seats. Furthermore, the synthetic leather is usually stored in a roll shape, but depending on the storage conditions, there are problems such as cracks in the synthetic leather and wrinkles remaining on the synthetic leather after rewinding.

Japanese Patent No. 3142102 JP 2003-119314 A JP 2004-346094 A Japanese Patent No. 4177318 JP 2009-185260 A

  An object of the present invention is to provide a synthetic leather that is excellent in the balance of physical properties such as sweat resistance and flexibility and that does not crack or wrinkle during storage.

As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using a specific polycarbonate diol, and has led to the present invention.
That is, the configuration of the present invention is as follows.
[1] A synthetic leather formed from a polyurethane resin comprising a reaction product of (a) an organic diisocyanate, (b) a polycarbonate diol, and (c) a chain extender,
The polycarbonate diol (b) is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, and 60 to 100 mol% of the repeating unit represented by the formula (A) is: It is a repeating unit represented by the formula (B) or (C), and the ratio of the repeating unit represented by the following formula (B) and the repeating unit represented by the following formula (C) is 90:10 to 10: 90. The above synthetic leather, characterized in that it is 90 (molar ratio), has a number average molecular weight of 800-3500, and has a primary terminal OH ratio of 95-99.5%.

  INDUSTRIAL APPLICABILITY The present invention has an effect that it is possible to provide a synthetic leather that has an excellent balance of physical properties such as sweat resistance and flexibility and that does not cause cracks or wrinkles during storage. Furthermore, the synthetic leather of the present invention is excellent in hydrolysis resistance and has a good surface without a feeling of roughness or stickiness.

  Hereinafter, the present invention will be specifically described.

Polyurethane resin In the present invention, the polyurethane resin comprises a reaction product of an organic diisocyanate (a), a polycarbonate diol (b), and a chain extender (c).

Organic diisocyanate (a)
Examples of the organic diisocyanate (a) used in the present invention include 2,4-triresin diisocyanate, 2,6-triresin diisocyanate and mixtures thereof, diphenylmethane-4,4′-diisocyanate (MDI), and naphthalene-1,5-diisocyanate. Aromatic diisocyanates such as (NDI), 3,3′-dimethyl-4,4′biphenylene diisocyanate (TODI), crude TDI, polymethylene polyphenylene polyisocyanate (PMDI), crude MDI, xylylene diisocyanate (XDI), phenylene diisocyanate Araliphatic diisocyanates such as 4,4′-methylenebiscyclohexyl diisocyanate (hydrogenated MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), An aliphatic diisocyanate such as rhohexane diisocyanate (hydrogenated XDI) can be mentioned, but is not limited thereto.

Usually, one type of organic diisocyanate is selected and used, but two or more types may be selected from these organic diisocyanates, and these may be mixed or sequentially added. The amount of organic diisocyanate used is usually 0.95 to 1.2 equivalents relative to the total amount of polycarbonate diol and chain extender.
When MDI is used as the organic isocyanate, a synthetic leather having excellent mechanical properties can be obtained, which is preferable. Further, when hydrogenated MDI is used, a synthetic leather excellent in light resistance is obtained, which is preferable.

Polycarbonate diol (b)
The polycarbonate diol (b) used in the present invention is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, and is 60 to 100 mol% of the repeating unit represented by the formula (A). Is a repeating unit represented by the following formula (B) or (C), and the ratio of the repeating unit represented by the following formula (B) to the repeating unit represented by the following formula (C) is 90:10. -10: 90 (molar ratio), number average molecular weight is 800-3500, and primary terminal OH ratio is 95-99.5%.
In the polycarbonate diol (b), the ratio of the repeating unit represented by the formula (A) is preferably 95 mol% to 100 mol%, more preferably 97 mol% to 100 mol%, and still more preferably 99 mol%. It is mol% or more and 100 mol% or less.

The primary terminal OH ratio of the polycarbonate diol (b) in the present invention is an alcohol obtained as an initial fraction by heating the polycarbonate diol at a temperature of 160 ° C. to 200 ° C. with stirring under a pressure of 0.4 kPa or less. Is defined as the weight percentage of the diol having primary hydroxyl groups at both ends to the total of alcohols (excluding ethanol) containing the diol. The alcohol containing diol here corresponds to the segment of the terminal portion of the polycarbonate diol. Specifically, the primary terminal OH ratio in the present invention is such that the polycarbonate diol (70 g to 100 g) is heated at a temperature of 160 ° C. to 200 ° C. with stirring under a pressure of 0.4 kPa or less. A fraction corresponding to about 1 to 2% by weight, i.e. about 1 g (0.7 to 2 g) of a fraction is obtained and recovered using about 100 g (95 to 105 g) of ethanol as a solvent. The value calculated by the following formula (1) from the value of the peak area of the chromatogram obtained by subjecting the recovered solution to gas chromatography (GC) analysis.
Primary terminal OH ratio (%) = A ÷ B × 100 (1)
A: Sum of peak areas of diols whose both ends are primary OH groups B: Sum of peak areas of alcohols (excluding ethanol) containing diols

  Specific examples of “alcohols containing diol (excluding ethanol)” detected in the GC analysis performed for the measurement of the primary terminal OH ratio are 1,5-pentanediol, 1,6- Examples include hexanediol, 1,4-butanediol, 1,5-hexanediol, 1,4-cyclohexanediol, 1,4-pentanediol, 1-butanol, 1-pentanol, and 1-hexanol. When the polycarbonate diol is heated at a temperature of 160 ° C. to 200 ° C. with stirring under a pressure of 0.4 kPa or less as described above, only the terminal portion of the polycarbonate diol is decomposed and evaporated to obtain a fraction. It is done. The ratio of the diol in which both ends of all alcohols in this fraction are primary OH groups is defined as the primary terminal OH ratio of the polycarbonate diol (b) in the present application.

  In polyurethane resins used for synthetic leather, aromatic diisocyanates such as MDI are often used as organic diisocyanates. Since aromatic diisocyanates are highly reactive, it is important to appropriately control the urethane reaction. When the reaction cannot be controlled, a fine gel is formed, and the surface of the synthetic leather becomes rough, and cracks may occur during storage or firewood may occur. Furthermore, when polyurethane is polymerized by the prepolymer method, it is also important to appropriately control the prepolymer reaction in which the organic isocyanate and the polycarbonate diol are reacted. When the reaction cannot be controlled, the molecular weight distribution of the prepolymer becomes wide, the molecular regularity of the polyurethane obtained by the reaction with the chain extender is lowered, and the flexibility and the compression recovery property of the synthetic leather may be lowered. If the primary terminal OH ratio of the polycarbonate diol (b) is 99.5% or less, the urethane reaction is appropriately controlled regardless of the type of organic diisocyanate used, and the resulting synthetic leather has a rough surface. There is no feeling and the occurrence of cracks and firewood during storage is effectively prevented. Furthermore, a polyurethane resin excellent in flexibility and compression recovery can be obtained.

  When an aliphatic diisocyanate having low reactivity is used when the end of the raw material diol is not a primary OH group, polymerization takes time and the molecular weight distribution of the resulting polyurethane is increased. When the amount of low molecular weight is increased, the strength of the synthetic leather is lowered and the synthetic leather having the desired thickness may not be obtained. In addition, the surface of the synthetic leather may become sticky and adhesion may occur during storage. If the primary terminal OH group ratio of the polycarbonate diol (b) is 95% or more, these problems are unlikely to occur. When the primary terminal OH group ratio is 96% or more, it is more preferable, and when it is 97% or more, the above problems due to the influence of low molecular weight substances hardly occur.

  The manufacturing method of polycarbonate diol (b) used by this invention is not specifically limited. For example, it can be produced by various methods described in Schnell, Polymer Reviews, Vol. 9, p9-20 (1994).

  The polycarbonate diol (b) used in the present invention uses 1,5-pentanediol and 1,6-hexanediol as diol raw materials. In addition to these diols, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, Diols having no side chain such as 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1, 3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl- Diols having side chains such as 1,3-propanediol and 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedi Pentanol, 2- bis (4-hydroxycyclohexyl) - cyclic diols such as propane, may be used one or more kinds of diol as a raw material. The amount is not particularly limited as long as the ratio of the repeating unit shown in the present invention is satisfied.

  Further, a compound having 3 or more hydroxyl groups per molecule, for example, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol, etc., is used within the range not impairing the performance of the polycarbonate diol (b) used in the present invention. You can also. When too many compounds having three or more hydroxyl groups in one molecule are used, gelation occurs due to crosslinking during the polymerization reaction of the polycarbonate. Therefore, even when a compound having three or more hydroxyl groups in one molecule is used, the compound is preferably 0.1 to 5% by mass with respect to the total amount of diols used as a raw material. More preferably, it is 0.1-2 mass%.

  The polycarbonate diol (b) used in the present invention includes, as carbonate ester, dialkyl carbonate such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, diaryl carbonate such as diphenyl carbonate, ethylene carbonate, trimethylene carbonate, 1,2- Examples include alkylene carbonates such as propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. Among these, one or more carbonate esters can be used as a raw material. The use of dialkyl carbonate and / or diaryl carbonate is preferred because the polycarbonate diol having a primary terminal OH ratio of the present invention can be easily obtained depending on conditions such as the charging ratio of diol and carbonate. Moreover, it is more preferable to use dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and dibutyl carbonate from the viewpoint of easy availability and easy setting of conditions for the polymerization reaction.

  In the production of the polycarbonate diol (b) used in the present invention, a catalyst may or may not be added. When adding a catalyst, it can select freely from a normal transesterification catalyst. For example, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic, cerium and other metals, salts, alkoxides, organic compounds Used. Particularly preferred are titanium, tin and lead compounds. Moreover, the usage-amount of a catalyst is 0.00001 to 0.1% of the polycarbonate diol weight normally obtained.

  As an example of the method for producing the polycarbonate diol (b), a method using dimethyl carbonate as the carbonate will be described. The production of the polycarbonate diol can be carried out in two stages. Diol and dimethyl carbonate are mixed at a molar ratio of 20: 1 to 1:10 and reacted at 100 to 300 ° C. under normal pressure or reduced pressure, and the resulting methanol is removed as a mixture with dimethyl carbonate to reduce the A molecular weight polycarbonate diol can be obtained. Next, heating at 160 to 250 ° C. under reduced pressure removes unreacted diol and dimethyl carbonate, and self-condenses the low molecular weight polycarbonate diol to obtain a polycarbonate diol having a predetermined molecular weight.

  The polycarbonate diol having a primary terminal OH ratio of the present invention is the polymerization conditions such as the purity of the raw material diol, temperature and time, and when a dialkyl carbonate or / and diaryl carbonate is used as the carbonate, the charging ratio of diol and carbonate, etc. From the above conditions, one method can be selected or appropriately combined.

  Industrially obtained 1,5-pentanediol contains 0.2 to 2% by weight of 1,5-hexanediol and 1,4-cyclohexanediol as impurities having secondary hydroxyl groups, respectively. On the other hand, 1,6-hexanediol obtained industrially contains 0.1 to 2% by weight of impurities having a secondary hydroxyl group such as 1,4-cyclohexanediol. Since these diols having secondary hydroxyl groups have low transesterification reactivity during the production of polycarbonate diols, they often become terminal groups of polycarbonate diols, resulting in polycarbonate diols having secondary hydroxyl groups at the ends.

  Also, when dialkyl carbonate and / or diaryl carbonate is used as the carbonate, the polycarbonate diol is prepared by reacting the diol and carbonate in a stoichiometric amount or a proportion close thereto in accordance with the molecular weight of the target polycarbonate diol. In many cases, an alkyl group or an aryl group derived from carbonate remains at the terminal of the. Therefore, by setting the amount of diol with respect to the carbonate to 1.01 to 1.30 times the stoichiometric amount, the terminal of the alkyl group or aryl group remaining at the terminal of the polycarbonate diol can be reduced to form a hydroxyl group. . Furthermore, due to side reactions, the end of the polycarbonate diol may become a vinyl group, or when dimethyl carbonate is used as a carbonate, for example, it may become a methyl ester or a methyl ether. In general, the side reaction is more likely to occur as the reaction temperature is higher and the reaction time is longer.

  In the polycarbonate diol (b) used in the present invention, the ratio of the repeating unit represented by the following formula (B) or (C) in the repeating unit represented by the above formula (A) (hereinafter referred to as “main component ratio”) Is 60 to 100 mol%. When the main component ratio is in the above range, a porous structure having a good performance balance such as hydrolysis resistance, heat resistance and flexibility can be obtained. In particular, when the main component ratio is 60 mol% or more, the softness of the synthetic leather is appropriately maintained, and the occurrence of a situation where the viscosity of the polycarbonate diol increases and the amount of solvent used increases is suppressed. . From these viewpoints, the main component ratio is more preferably 70 to 100 mol%. It is most preferable when the main component ratio is 85 to 100 mol%.

  In the polycarbonate diol (b) used in the present invention, the ratio of the repeating unit represented by the above formula (B) and the repeating unit represented by (C) (hereinafter referred to as “copolymerization ratio”) ): Represented by the above formula (C)) is 90:10 to 10:90 in molar ratio. If the copolymerization ratio is within this range, a synthetic leather having high flexibility can be obtained. Furthermore, when the copolymerization ratio is 70:30 to 30:70, the crystallinity of the polycarbonate diol is lowered, and it is preferable that no cracks occur during storage and no soot is generated. It is more preferable when the copolymerization ratio is 60:40 to 40:60.

  Conventionally, polycarbonate diol consists of a repeating unit represented by the above formula (C) and a terminal hydroxyl group, has high crystallinity, has high hydrolysis resistance, heat resistance and chemical resistance, but lacks flexibility. However, depending on the composition of the urethane resin, there is a problem that cracks occur during storage and firewood is generated. In the present invention, the repeating unit of the above formula (C) is close in methylene chain length, has no branched structure, and has a odd number of methylene chains (repeating unit of the above formula (B)) to reduce crystallinity. , By having a specific main component ratio and copolymerization ratio, it maintains strength and flexibility while maintaining high hydrolysis resistance, heat resistance and chemical resistance, and does not generate cracks or generation of firewood during storage I found that I can get leather.

  The range of the average molecular weight of the polycarbonate diol (b) used in the present invention is 800 to 3500 in terms of number average molecular weight. If the number average molecular weight of the polycarbonate diol is 800 or more, the strength and flexibility of the synthetic leather can be maintained, and cracking and firewood during storage will not decrease. If the number average molecular weight of the polycarbonate diol is 3500 or less, the viscosity is not excessively high, the handling is easy, and a large amount of solvent is not required for polymerization of polyurethane. More preferably, the number average molecular weight of the polycarbonate diol is 1000 to 3000.

The polycarbonate diol (b) of the present invention may contain a structure represented by a repeating unit of the following formula (D) in the molecule for the purpose of improving flexibility.

  In the polycarbonate diol (b) of the present invention, the content of the repeating unit of the formula (D) in the molecule is not particularly limited as long as it does not affect the present invention. And chemical resistance decreases. Accordingly, when the repeating unit represented by the formula (D) is introduced, the repeating unit of the carbonate represented by the formula (A) is represented by the formula (D) (having an ether-derived structure). The repeating unit is preferably 0.05 to 5 mol% or less, and more preferably 0.05 to 3 mol% or less.

Chain extender (c)
Examples of the chain extender (c) used in the present invention include short-chain diols such as ethylene glycol and 1,4-butanediol, ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diphenyldiamine, and diamino. Examples include, but are not limited to, diamines such as diphenylmethane, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, and water. Normally, one type of chain extender is selected and used, but two or more types may be selected from these chain extenders and used in combination. The amount of chain extender used is usually 50 to 500 moles, where the number of moles of polycarbonate diol (b) is 100.

Production of polyurethane resin The polyurethane resin of the present invention can be obtained by methods known in the polyurethane industry. For example, a polycarbonate diol and an organic diisocyanate are reacted at 20 to 150 ° C. for 2 to 12 hours to synthesize a urethane prepolymer having an isocyanate group at the end, and then a chain extender is added thereto to 20 to 150 ° C. Or a prepolymer method for obtaining a polyurethane resin having a target molecular weight by reacting for 2 to 12 hours, or a polycarbonate diol, an organic isocyanate, and a chain extender are added all at once, There is a one-shot method in which a polyurethane resin having a target molecular weight is obtained by reacting for 12 hours.

  If necessary, polyols other than polycarbonate diol can be added and used. Examples of usable polyols include polyester-based polyols, polyether-based polyols, polycaprolactone-based polyols, acrylic polyols, polyolefin polyols, and castor oil polyols, which can be used alone or in combination. The amount of these polyols used is not particularly limited as long as the properties of the prepolymer of the present invention are not impaired. Usually, the amount is 50% by mass or less, preferably 30% or less, more preferably 10% by mass with respect to the polycarbonate diol. % Or less.

  In this reaction, a urethane reaction catalyst can be added as necessary. Examples of the catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and morpholine, metal salts such as potassium acetate, zinc stearate and tin octylate, and organometallic compounds such as dibutyltin dilaurate. A polymerization terminator can also be added as needed. As the polymerization terminator, monohydric alcohols such as methanol, butanol and cyclohexanol, dibutylamine and the like can be used.

  These reactions may be performed in an organic solvent. As the organic solvent, dimethylformamide (DMF), dimethylsulfoxide, diethylformamide, dimethylacetamide, tetrahydrofuran (THF), methyl ethyl ketone (MEK), dioxane, acetone, cyclohexane, toluene and the like can be used. These organic solvents can be used as one kind or a mixture of two or more kinds. Generally, an organic solvent is used so that the density | concentration of the polyurethane resin obtained may be 5 to 50 weight%.

  The polyurethane resin of the present invention is dissolved in an organic solvent and used as a polyurethane resin solution for the production of synthetic leather. As the organic solvent, dimethylformamide (DMF), dimethylsulfoxide, diethylformamide, dimethylacetamide, tetrahydrofuran (THF), methyl ethyl ketone (MEK), dioxane, acetone, cyclohexane, toluene and the like can be used. These organic solvents can be used as one kind or a mixture of two or more kinds. The concentration of the polyurethane resin solution in the organic solvent is generally 5 to 50% by weight.

  A film forming aid may be added to the polyurethane resin solution. As film forming aids, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, melicic acid and other aliphatic carboxylic acids having a relatively large number of carbon atoms, octyl alcohol, nonyl alcohol, decyl Long chain alcohols such as alcohol, dodecyl alcohol, tetradecyl alcohol, cetyl alcohol, stearyl alcohol and the like can be mentioned. Furthermore, a carboxylic acid ester obtained from an alkyl alcohol having 1 to 6 carbon atoms and an aliphatic carboxylic acid having 6 to 18 carbon atoms, a carboxylic acid monoester or diester obtained from glycerin and an aliphatic carboxylic acid having 10 to 22 carbon atoms, Carboxylic acid monoesters and diester triesters obtained from triesters, sorbitans and C10-22 aliphatic carboxylic acids.

  If necessary, the polyurethane resin solution may include a colorant, an antioxidant, an ultraviolet absorber, a flame retardant, a water / oil repellent, a deodorant, an antistatic agent, an aromatic, a release agent, a lubricant, a filler, An additive such as a foaming agent may be added alone or in combination of two or more. Furthermore, if necessary, synthetic rubber, polyvinyl chloride or vinyl chloride copolymer, vinyl acetate or vinyl acetate copolymer, amino acid resin, polyurethane / polyamino acid block copolymer, polyester elastomer, polyamide elastomer, polyamide, etc. A polymer can also be added.

Manufacture of synthetic leather As a method of manufacturing the synthetic leather of the present invention, there are a wet method in which a polyurethane resin solution is applied or impregnated on a substrate and wet coagulated, and a dry method in which the polyurethane resin solution is applied to a release paper or substrate and dried. is there. Furthermore, it is also possible to use a transfer coating method in which a release resin is removed after a polyurethane resin solution is applied to the release paper and a substrate is bonded to the release paper via an adhesive layer.

The wet method will be described below as an example.
Various substrates can be used as the substrate. For example, examples of the fibrous base material include a fiber assembly in which the fibers are formed into a nonwoven fabric, a woven fabric, a net cloth, or the like, or a fiber assembly in which each fiber of the fiber assembly is bonded with an elastic polymer. Examples of fibers used in the fiber assembly include natural fibers such as cotton, hemp, and wool, regenerated or semi-synthetic fibers such as rayon and acetate, and synthetic fibers such as polyamide, polyester, polyacrylonitrile, polyvinyl alcohol, and polyolefin. . These fibers may be single-spun fibers or mixed-spun fibers. Examples of other substrates include paper, release paper, polyester and polyolefin plastic films, metal plates such as aluminum, and glass plates.

  When the substrate is a raised fabric, a knitted fabric, or a non-woven fabric, the polyurethane resin solution applied to the surface easily penetrates into the substrate, and the flexibility is inferior. Therefore, it is possible to pre-treat the substrate in advance. As the pretreatment method, there are a method of treating the substrate with a fluorine-based water repellent or the like, and a method of crushing and smoothing the swelling of the substrate through a calendar.

  The polyurethane resin solution can be applied and impregnated by a generally used method. Examples of the coating method include a floating knife coater, a knife over roll coater, a reverse roll coater, a roll doctor coater, a gravure roll coater, and a kiss roll coater.

  As a wet coagulation method, for example, a base material impregnated or coated with a polyurethane resin solution has an affinity with a solvent of the polyurethane resin solution, and the polyurethane resin has no affinity and is directly immersed in a coagulation bath which is a non-solvent. There is a method of coagulating by extracting the organic solvent. Examples of non-solvents that have an affinity for the above organic solvent and no affinity for polyurethane resins include water, ethylene glycol, glycerin, ethylene glycol monoethyl ether, and hydroxyethyl acetate. A mixture of more than one type can be used. Furthermore, an organic solvent can also be mixed and used in arbitrary ratios.

  The temperature of the coagulation bath is usually 30 to 50 ° C. By setting the temperature of the coagulation bath in such a temperature range, a porous structure can be easily obtained when using a polycarbonate diol-based polyurethane resin, which is practically preferable. The coagulation process can be performed continuously in several stages. In this case, the first stage coagulation bath temperature is preferably 30 to 50 ° C. In the coagulation bath after the first stage, the temperature can be set on either the high temperature side or the low temperature side as necessary. After wet coagulation, washing and drying can be performed by ordinary methods.

  In the present invention, when the substrate has a large porosity such as a knitted fabric, when the polyurethane resin solution is directly applied or impregnated, the polyurethane resin may penetrate into the entire substrate and reduce flexibility. In that case, a laminating method in which an adhesive is interposed may be employed. As the adhesive, polyurethane, polyacryl, polyamide, polyester, or the like can be used, but it is preferable to use polyurethane. The method of applying the adhesive can be applied to the entire surface of the synthetic leather, but from the viewpoint of texture and moisture permeability, a method of applying the adhesive to the synthetic leather in a dotted or linear manner and laminating is preferable.

  The obtained synthetic leather can be used as it is. Alternatively, for the purpose of imparting various properties, this synthetic leather is coated with a polymer solution or emulsion such as polyurethane resin, vinyl chloride or cellulose resin, or separately coated on release paper. It can also be used as a laminate obtained by peeling the release paper after pasting with a coating film obtained by drying.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited at all by these examples.
The physical property values shown in the following examples and comparative examples were measured by the following methods.

1) Primary terminal OH ratio of polycarbonate diol The primary terminal OH ratio of polycarbonate diol was measured by the following method. 70 to 100 g of polycarbonate diol was weighed into a 300 cc eggplant flask and stirred at about 180 ° C. under a pressure of 0.1 kPa or less using a rotary evaporator connected to a trap bulb for collecting fractions. The polycarbonate diol was heated in a heating bath to obtain an initial fraction in an amount corresponding to 1 to 2% by weight of the polycarbonate diol, that is, about 1 g (0.7 to 2 g) of the initial fraction. This was recovered using about 100 g (95 to 105 g) of ethanol as a solvent, and the peak value of the chromatogram obtained by subjecting the recovered solution to GC analysis was calculated by the following formula (1).
Primary terminal OH ratio (%) = A ÷ B × 100 (1)
A: Sum of peak areas of diols whose both ends are primary OH groups B: Sum of peak areas of alcohols (excluding ethanol) containing diol Gas chromatographic analysis conditions: Column; DB-WAX (US & J Company) Manufactured), 30 m, film thickness 0.25 μm, temperature rising condition: 60 ° C. to 250 ° C., detector: FID (flame ionization detector)

2) Number average molecular weight of polycarbonate diol The hydroxyl value is determined by “neutralization titration method (JIS K 0070-1992)” in which acetic anhydride and pyridine are used and titrated with an ethanol solution of potassium hydroxide. Used to calculate the number average molecular weight.
Number average molecular weight = 2 / (OH value × 10 ⁻³ /56.1) (2)

3) Copolymerization ratio and main component ratio of polycarbonate diol 1 g of a sample was taken into a 100 ml eggplant flask, and 30 g of ethanol and 4 g of potassium hydroxide were added and reacted at 100 ° C. for 1 hour. After cooling the reaction solution to room temperature, 2-3 drops of phenolphthalein was added to the indicator and neutralized with hydrochloric acid. After cooling in the refrigerator for 1 hour, the precipitated salt was removed by filtration and analyzed using GC (gas chromatography). GC analysis was performed using gas chromatography GC-14B (manufactured by Shimadzu Corporation, Japan) with DB-WAX (manufactured by J & W, USA) as a column, diethylene glycol diethyl ester as an internal standard, and FID as a detector. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min.

(I) Copolymerization ratio Using the above analysis results, from the molar ratio of 1,5-pentanediol and 1,6-hexanediol, the copolymerization ratio (of 1,5-pentanediol when the whole is 100) The number of moles: the number of moles of 1,6-hexanediol).
(Ii) Main component ratio It calculated | required by following Numerical formula (3) using said analysis result.
Main component ratio (mol%) = {(B + C) / A} × 100 (3)
A: Total number of moles of diol derived from the repeating unit of the above formula (A)
B: Number of moles of 1,5-pentanediol
C: Number of moles of 1,6-hexanediol

4) Purity analysis of polycarbonate diol raw material diol 1,5-hexanediol and 1,6-hexanediol used as diol raw materials were analyzed by gas chromatography. The conditions were as follows. Gas chromatography GC-14B (manufactured by Shimadzu Corporation) with DB-WAX (manufactured by J & W) as a column was used, diethylene glycol diethyl ester was used as an internal standard, and FID was used as a detector. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min.

5) Sweat resistance of synthetic leather Oleic acid was used as a substitute for sweat. The sample was immersed in oleic acid at 45 ° C. for 1 week, and the surface was observed. The case where there was no change from before immersion (◯), the case where a feeling of slimness was felt (Δ), and the case where the surface shape was changed (×) were evaluated for the sweat resistance of the synthetic leather.

6) Softness of synthetic leather The softness of the synthetic leather was evaluated based on the feeling of touch based on the synthetic leather prepared in Comparative Example 2 described later. The case where it was softer than this standard synthetic leather was indicated as (◯), the case where it did not change was indicated as (Δ), and the case where it was hard was indicated as (×).

7) Evaluation of the surface feel of the synthetic leather The surface feel of the synthetic leather was evaluated based on a sticky feeling and a rough feeling. The evaluation was performed by five inspectors, and the touch when the surface of the synthetic leather was touched with a hand was scored based on the following criteria and expressed as an average score.
(I) Evaluation of stickiness A score of 0 to 5 was assigned with 0 points for non-stickiness and 5 points for strong stickiness.
(Ii) Evaluation of Roughness A score of 0 to 5 was assigned, with 0 being the case where there was no roughness and 5 points for the case where there was a general feeling of roughness.

8) Storage stability of synthetic leather Synthetic leather was wound around a paper tube having a diameter of 10 cm and stored in a temperature-controlled room at 23 ° C and 50% humidity for 1 month. The synthetic leather was removed from the paper tube and left in a temperature-controlled room at a temperature of 23 ° C. and a humidity of 50% for 1 day, and then the surface was visually observed. The case where there were no cracks or wrinkles at all (◯), the case where minute cracks or wrinkles of 1 mm or less were observed (Δ), and the case where cracks or wrinkles exceeding 1 mm were observed were scored as (×).

[Polycarbonate diol polymerization example 1]
1,5-pentanediol and 1,6-hexanediol used as raw materials were analyzed. The 1,5-pentanediol had a purity of 98.5% and contained 1.1% by mass of 1,5-hexanediol and 0.1% by mass of 1,4-cyclohexanediol. The remaining 0.3% by mass was a plurality of unknown items. The 1,6-hexanediol had a purity of 98.9% and contained 0.6% by mass of 1,4-cyclohexanediol. The remaining 0.5% by mass was a plurality of unknown items. In the following polymerization examples, the raw materials were used except for Polymerization Examples 8 and 12.

  In a 2 L glass flask equipped with a rectifying column packed with a regular packing and a stirrer, 430 g (4.8 mol) of dimethyl carbonate, 260 g (2.5 mol) of 1,5-pentanediol, 1,6- 310 g (2.6 mol) of hexanediol was charged. Titanium tetrabutoxide (0.09 g) was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C. and the pressure was 10 to 15 kPa, and the reaction was performed for 6 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC1.

[Polycarbonate diol polymerization example 2]
Using the same apparatus as in Polymerization Example 1, 420 g (4.7 mol) of dimethyl carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 270 g (2.3 mol) of 1,6-hexanediol were charged. Titanium tetrabutoxide 0.08 g was added as a catalyst, and the reaction was performed under the same conditions as in Polymerization Example 1. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC2.

[Polycarbonate diol polymerization example 3]
Using the same apparatus as in the above Polymerization Example 1, 500 g (4.2 mol) of diethyl carbonate, 150 g (1.4 mol) of 1,5-pentanediol, and 350 g (3.0 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 10 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 190 ° C., the pressure was 10 to 15 kPa, and the reaction was performed for 6 hours while distilling off the mixture of ethanol and diethyl carbonate to be produced. Then, it was made to react at 190 degreeC for 8 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC3.

[Polymerized diol polymerization example 4]
Using the same apparatus as in Polymerization Example 1, 465 g (5.3 mol) of ethylene carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 330 g (2.8 mol) of 1,6-hexanediol were charged. 0.10 g of titanium tetrabutoxide was added as a catalyst, and the mixture was stirred and heated at normal pressure. The reaction temperature was 150 ° C. to 190 ° C., the pressure was 3.0 to 5.0 kPa, and the reaction was carried out for 16 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Thereafter, the pressure was reduced to 0.5 kPa, and the reaction was further continued at 190 ° C. for 8 hours while distilling off ethylene carbonate and diol. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC4.

[Polymerized diol polymerization example 5]
Using the same apparatus as in Polymerization Example 1, the raw materials were charged under the same conditions. The mixture was heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and the mixture was reacted for 7 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Thereafter, the reaction was carried out at a reaction temperature of 150 ° C. to 190 ° C. and a pressure of 10 to 15 kPa for 3 hours while distilling off the resulting mixture of methanol and dimethyl carbonate. Then, it was made to react at 190 degreeC for 3 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC5.

[Polymerized diol polymerization example 6]
Using the same apparatus as in Polymerization Example 1, the raw materials were charged under the same conditions as in Polymerization Example 5. 0.10 g of titanium tetrabutoxide was added as a catalyst, and the mixture was stirred and heated at normal pressure. The reaction temperature was 150 ° C. to 190 ° C., the pressure was 3.0 to 5.0 kPa, and the reaction was carried out for 10 hours while distilling off the mixture of ethylene glycol and ethylene carbonate to be produced. Thereafter, the pressure was reduced to 0.5 kPa, and the mixture was further reacted at 190 ° C. for 5 hours while distilling off ethylene carbonate and diol. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC6.

[Polymerized diol polymerization example 7]
The reaction was carried out under the conditions of Polymerization Example 4 above, and the reaction was further carried out at 190 ° C. for 10 hours while distilling off the diol at 0.5 kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC7.

[Polymerized diol polymerization example 8]
Raw materials 1,5-pentanediol and 1,6-hexanediol were purified by distillation. As a result, 1,5-pentanediol had a purity of 98.9% and contained 0.4% by mass of 1,5-hexanediol, but 1,4-cyclohexanediol was not detected. The remaining 0.7% by mass was a plurality of unknown items. The 1,6-hexanediol had a purity of 99.1% and contained 0.3% by mass of 1,4-cyclohexanediol. The remaining 0.6 mass% was a plurality of unknown items. Polycarbonate diol was polymerized using the above raw materials.

  The apparatus shown in Polymerization Example 3 above, except that 570 g (4.8 mol) of diethyl carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 315 g (2.7 mol) of 1,6-hexanediol were used. The reaction was conducted under conditions. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC8.

[Polymerized diol polymerization example 9]
Using the same apparatus as in Polymerization Example 1, 460 g (3.9 mol) of diethyl carbonate, 100 g (0.7 mol) of 1,5-pentanediol, and 370 g (3.1 mol) of 1,6-hexanediol were charged. Titanium tetrabutoxide (0.10 g) was added as a catalyst, and the reaction was carried out under the same conditions as in Polymerization Example 3. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC9.

[Polymerized diol polymerization example 10]
Using the same apparatus as in Polymerization Example 1, 430 g (4.8 mol) of dimethyl carbonate and 590 g (5.0 mol) of 1,6-hexanediol were charged. Titanium tetrabutoxide 0.09 g was added as a catalyst, and the reaction was carried out under the same conditions as in Polymerization Example 1. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC-10.

[Polymerized diol polymerization example 11]
Using the same apparatus as in Polymerization Example 1, 460 g (5.1 mol) of dimethyl carbonate, 260 g (2.5 mol) of 1,5-pentanediol, and 280 g (2.4 mol) of 1,6-hexanediol were charged. Titanium tetrabutoxide 0.09 g was added as a catalyst, heated and stirred at a temperature of 140 to 150 ° C. under normal pressure, and reacted for 5 hours while distilling off the resulting mixture of ethanol and diethyl carbonate. Thereafter, the reaction temperature was 150 ° C. to 210 ° C. and the pressure was 9 to 15 kPa, and the reaction was performed for 6 hours while distilling off the mixture of ethanol and diethyl carbonate to be produced. Then, it was made to react at 210 degreeC for 6 hours, reducing pressure gradually to 0.5kPa. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC11.

[Polymerized diol polymerization example 12]
The reaction was carried out using the apparatus and conditions shown in Polymerization Example 4 except that the raw materials used in Polymerization Example 8 were used. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC-12.

[Polymerized diol polymerization example 13]
Using the same apparatus as in Polymerization Example 1, 430 g (4.8 mol) of dimethyl carbonate and 550 g (5.3 mol) of 1,5-pentanediol were charged. Titanium tetrabutoxide 0.09 g was added as a catalyst, and the reaction was carried out under the same conditions as in Polymerization Example 1. The results of analyzing the obtained polycarbonate diol are shown in Table 1. This polycarbonate diol is referred to as PC-13.

[Polymerization Examples 1 to 13 of Polyurethane Resin]
A reactor equipped with a reflux condenser, a thermometer, and a stirrer was charged with 350 g of polycarbonate diol (hereinafter abbreviated as PCD) and dimethylformamide (hereinafter abbreviated as DMF) and sufficiently stirred. Subsequently, isophorone diisocyanate (hereinafter abbreviated as IPDI) and dibutyltin dilaurate as a catalyst were added and reacted at 75 ° C. for 5 hours to obtain an isocyanate-terminated prepolymer. After the temperature was lowered to 40 ° C., isophoronediamine (hereinafter abbreviated as IPDA) was added, and when the number average molecular weight reached 50,000, 1 g of n-hexylamine was added to stop the reaction. Then, DMF was added so that solid content might be 30 mass%, it stirred uniformly, the polyurethane resin solution was prepared, and it used for manufacture to synthetic leather.
Table 2 below shows the charged amounts of each raw material of the polyurethane resin. The obtained polyurethane resins are referred to as PUR1 to PUR13, respectively.

[Example 1]
70 denier nylon 66 base fabric (warp density 136 / inch, weft density 104 / inch) in a bath containing 0.8% fluorinated water repellent (Aseihi LS317, manufactured by Meisei Chemical Co., Ltd.) After dipping and squeezing at a squeezing rate of 80%, it was dried with a dryer at 150 ° C. for 5 minutes. On the base fabric, the polyurethane resin solution PUR1 was applied with a clearance of 100 μm using an applicator. After dipping in a 10% DMF aqueous solution at 25 ° C. for 5 minutes for wet solidification, the solvent was removed by immersion in warm water at 65 ° C. for 5 minutes. Subsequently, it squeezed with a squeeze roll and dried at 110 ° C. to obtain a synthetic leather 1.

[Examples 2 to 8]
Synthetic leathers 2-8 were obtained in the same manner as in Example 1 except that the polyurethane resin solutions PUR2-4 or PUR6-9 were used.

[Comparative Examples 1-5]
Synthetic leather 9-13 was obtained by the same method as Example 1 except having used polyurethane resin solution PUR5 or PUR10-13.

  With respect to the obtained synthetic leathers 1 to 13 (the synthetic leathers of Examples 1 to 8 and Comparative Examples 1 to 5), the flexibility, sweat resistance, surface stickiness, surface roughness and storage stability were evaluated. The results are shown in Table 3 below.

[Example 9]
The polyurethane resin solution PUR1 was applied to a polyethylene terephthalate film peel-treated with a silicon-based resin with a thickness of about 100 μm using a reverse roll coater. Then, it heated for 8 minutes at 120 degreeC, it accumulated on the base fabric used in Example 1, and bonded together using the calender roll heated to 120 degreeC. After curing at 80 ° C. for 36 hours, the polyethylene terephthalate film was peeled off to obtain a synthetic leather.

  According to the present invention, the composition has an excellent balance of physical properties such as sweat resistance, hydrolysis resistance and flexibility, and does not cause cracks or wrinkles during storage, and has a good surface with no roughness or stickiness. You can get leather. This synthetic leather can be suitably used for applications such as automobile seats, interior materials, clothing, shoes, bags, miscellaneous goods, and furniture.

Claims (1)

A synthetic leather formed from a polyurethane resin comprising a reaction product of (a) an organic diisocyanate, (b) a polycarbonate diol, and (c) a chain extender,
The polycarbonate diol (b) is a polycarbonate diol having a repeating unit represented by the following formula (A) and a terminal hydroxyl group, and 60 to 100 mol% of the repeating unit represented by the formula (A) is: It is a repeating unit represented by the formula (B) or (C), and the ratio of the repeating unit represented by the following formula (B) and the repeating unit represented by the following formula (C) is 90:10 to 10: 90. The above synthetic leather, characterized in that it is 90 (molar ratio), has a number average molecular weight of 800-3500, and has a primary terminal OH ratio of 95-99.5%.