JP2010189797A - Synthetic imitation leather, method for producing the same, prepolymer, and adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic imitation leather producible without using organic solvents and water to reduce energy consumption for evaporation and removal of the solvent, and reducing energy consumption for heating owing to treatment temperature of 20-80°C, by using an environmentally friendly adhesive scarcely releasing volatile organic materials in air. <P>SOLUTION: The synthetic imitation leather is composed of a substrate, an adhesive layer and a surface skin layer, wherein the adhesive layer contains a photo-polymerizable urethane prepolymer having a radically polymerizable unsaturated group and a hydroxyl group and the radically polymerizable unsaturated group has an unsaturated equivalent of 4,000-200,000. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a synthetic artificial leather (artificial leather, synthetic leather, leather) and a method for producing the same, and more specifically, an organic solvent having a large environmental impact, and a substantially 100% non-volatile urethane prepolymer that does not use water. The present invention relates to an environment-friendly synthetic artificial leather in which a polymer is used as an adhesive component and energy consumption is reduced due to solvent evaporation and a method for producing the same.

Examples of environmentally friendly urethane resins that are conventionally used in the manufacture of synthetic artificial leather include water-based types, TPU types, hot melt types, NCO-based block types, and the like, and adhesives that bond a base material to a skin layer For example, an aqueous type (Patent Document 1), a hot melt type (Patent Document 2), and an NCO-based block type (Patent Document 3) are known.
JP 2002-086662 A JP 2003-049147 A JP 2006-070058 A

  However, in the above, the water-based adhesive has a high energy consumption amount due to the evaporation and removal of water, and the hot melt type adhesive requires a high temperature heating of 120 to 150 ° C. and has a considerable energy consumption amount. Further, the NCO-based block type adhesive has a problem that the blocking agent is dissociated when the adhesive is cured, and the dissociated blocking agent is released.

  Therefore, the object of the present invention is to reduce the energy consumption required for evaporative removal without using an organic solvent or water, and further reduce the energy consumption required for heating by handling at 20 ° C. to 80 ° C. It is intended to provide a synthetic artificial leather using an environmentally friendly adhesive that hardly releases volatile organic matter therein, a method for producing the same, and the like.

  The above object is achieved by the present invention described below. That is, the present invention comprises a substrate, an adhesive layer, and a skin layer, and the adhesive layer contains a radical polymerizable unsaturated group and a hydroxyl group, and the unsaturated equivalent of the radical polymerizable unsaturated group is A synthetic artificial leather comprising a photopolymerizable urethane prepolymer of 4,000 to 200,000.

  In the above, the urethane prepolymer is substantially 100% non-volatile and liquid at 20 to 80 ° C .; the urethane prepolymer has a hydroxyl value of 5 to 200 mgKOH / g; a radical polymerizable unsaturated group Derived from an isocyanate group-containing (meth) acrylate; and the adhesive is 0.5 to 50 parts by mass of a polyfunctional unsaturated group-containing reactive monomer with respect to 100 parts by mass of the urethane prepolymer. It preferably consists of 0.1 to 10 parts by mass of the agent and 2 to 30 parts by mass of the polyisocyanate crosslinking agent having an NCO content of 5 to 30% by mass.

  In the present invention, the adhesive layer surface is applied to the surface of the skin layer (the surface opposite to the surface in contact with the release paper), and the adhesive is cured with active energy rays. There is provided a method for producing a synthetic artificial leather, characterized in that a base material is laminated on the substrate, and the adhesive is crosslinked and cured by heating and aging.

  The present invention also provides a photopolymerizable urethane comprising a radically polymerizable unsaturated group and a hydroxyl group, wherein the unsaturated equivalent of the radically polymerizable unsaturated group is 4,000 to 200,000. A prepolymer is provided. The urethane prepolymer is substantially 100% non-volatile and is liquid at 20 to 80 ° C .; and the radical polymerizable unsaturated group is preferably derived from an isocyanate group-containing (meth) acrylate.

  Moreover, this invention is 0.5-50 mass parts of polyfunctional unsaturated group containing reactive monomers, 0.1-10 mass parts of photoinitiators, and NCO content rate with respect to 100 mass parts of said urethane prepolymers. Comprising 2 to 30 parts by mass of a polyisocyanate crosslinking agent having a content of 5 to 30% by mass.

  According to the present invention, energy consumption required for evaporative removal is reduced without using an organic solvent or water, and further, energy consumption required for heating is reduced by handling at 20 ° C. to 80 ° C. It is possible to provide a synthetic artificial leather using an environmentally friendly adhesive that hardly emits volatile organic substances to the substrate, a method for producing the same, and the like.

  In order to achieve the above object, the present inventors use, as an adhesive, a urethane prepolymer containing a radically polymerizable unsaturated group having a solid content of approximately 100% by mass that is liquid at 20 to 80 ° C. as an adhesive. Before being bonded to a substrate such as a nonwoven fabric, woven fabric, knitted fabric, etc., a pre-polymer is formed after forming a cross-linked film to such an extent that the adhesive does not impregnate the substrate by irradiation with active energy rays. The process of producing a synthetic artificial leather by increasing the molecular weight of was found.

  In general, in order to set a urethane prepolymer to a liquid state at 20 ° C. with a solid content of 100%, there is a restriction that an amorphous polyol or diisocyanate compound is used at 20 ° C. and the molecular weight is shortened. When the prepolymer is applied as it is as an adhesive, the flow phenomenon of the coating film occurs due to the fluidity of the above-mentioned prepolymer derived from short molecules, and from the excessive impregnation of the prepolymer to the substrate, It causes a decrease in adhesive strength with the substrate and hardening of synthetic artificial leather.

  Therefore, after coating the skin layer with an adhesive, it is necessary to form a film suitable for bonding with the base material on the surface of the skin layer in a short time until the skin layer is bonded to the base material. The present inventors solved this problem by introducing a radical reaction mechanism into the urethane prepolymer for adhesives.

  That is, in the present invention, the urethane prepolymer (adhesive) applied to the skin layer has a conventional cross-linked structure by radical reaction and suppresses the fluidity of the short polymer-derived prepolymer, and is suitable for the surface of the skin layer. After finishing the film, a step of bonding the skin layer to the base material with the above adhesive was incorporated. Synthetic artificial leather excellent by increasing the molecular weight of the prepolymer (adhesive) by reacting the hydroxyl group or urethane group of the prepolymer with a polyisocyanate crosslinking agent after the skin layer is bonded to the substrate. Can be obtained.

  Next, the present invention will be described in more detail with reference to preferred embodiments. In the present invention, in the production of synthetic artificial leather, before the skin layer is bonded to the base material, the adhesive composition applied to the skin layer is subjected to radical crosslinking reaction, and the skin layer is bonded to the base material. By performing two-stage curing that causes the layer to undergo a crosslinking reaction (high molecular weight), a synthetic pseudo leather having high peel strength and excellent flexibility is obtained using a solventless prepolymer that is liquid at 20 to 80 ° C. as an adhesive. It is done.

  In the case of forming an adhesive layer on the surface of the skin layer, in addition to the above prepolymer, an adhesive composition further containing a polyfunctional unsaturated group-containing reactive monomer, a photopolymerization initiator, a polyisocyanate crosslinking agent, etc. It is applied to the surface of the skin layer, and the adhesive layer is irradiated with an active energy ray such as an ultraviolet ray or an electron beam to form a crosslinked film suitable for bonding to the substrate. Thereafter, the skin layer is bonded to the base material, and an adhesive layer excellent in adhesion to the base material is formed by an aging process (for example, 60 ° C./5 days) to obtain a synthetic artificial leather excellent in peel strength and texture. Can do.

  In this invention, it is preferable to mix a polyfunctional unsaturated group containing reactive monomer with an unsaturated group containing urethane prepolymer. That is, in order to suppress an increase in the viscosity of the prepolymer accompanying the introduction of an unsaturated group into the urethane prepolymer and to form an adhesive layer film suitable for bonding to the base material on the surface of the skin layer using the prepolymer. In addition to the crosslinking of the prepolymer, it is necessary to supplement the crosslinking with a reactive monomer. By changing the mixing amount of the reactive monomer, it is possible to adjust the adhesive strength and texture between the skin layer and the substrate. The preferable composition of the adhesive composition is 0.5 to 50 parts by mass of a polyfunctional unsaturated group-containing reactive monomer with respect to 100 parts by mass of the photopolymerizable urethane prepolymer having a radically polymerizable unsaturated group. 0.1 to 10 parts by mass of the agent and 2 to 30 parts of the polyisocyanate crosslinking agent having an NCO content of 5 to 30% by mass.

  The said prepolymer will not be specifically limited if it is a prepolymer which has a radically polymerizable unsaturated group which can be bridge | crosslinked with an active energy ray in a molecule | numerator. Further, even if a prepolymer that theoretically does not contain an unsaturated group is mixed with the unsaturated equivalent, there is no particular problem as long as the entire prepolymer is within the range of the unsaturated equivalent of the present invention. The unsaturated equivalent should be in the range of 4,000 to 200,000. Here, the unsaturated equivalent means the theoretical molecular weight of the urethane prepolymer per unsaturated bond.

  Preferred unsaturated group-containing prepolymers include, for example, prepolymers having unsaturated groups such as acryloyl groups, methacryloyl groups, vinyl ether groups, and allyl groups as radically polymerizable unsaturated groups. A preferred prepolymer is a prepolymer having an acryloyl group or a methacryloyl group.

  The number average molecular weight of the prepolymer is preferably 1,500 to 10,000, particularly preferably 3,000 to 6,000. When the number average molecular weight is less than 1,500, a liquid flow phenomenon occurs after the adhesive is applied, and a uniform film cannot be formed. On the other hand, if the number average molecular weight exceeds 10,000, the adhesive is solidified at room temperature, and high temperature heating of the adhesive is required at the time of application of the adhesive, which is not preferable because energy consumption increases.

  The prepolymer is a urethane prepolymer having an unsaturated bond in the molecular chain and is liquid at 20 to 80 ° C., but is not particularly defined by viscosity.

  Examples of polyols that can be used in producing the prepolymer include polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, butadiene polyols, polyacryl polyols, oil-modified polyols, silicone-modified polyols, Polycaprolactone polyol, polyvalerolactone polyol, and the like, or a mixture thereof. In order to give the prepolymer fluidity at 20 to 80 ° C., a polyol that is liquid at 20 ° C. or a mixture of the polyols as a polyol. A liquid composition is preferable. The prepolymer can be copolymerized with a short-chain glycol in order to improve the strength and durability of the high molecular weight coating.

  Examples of the isocyanate compound that can be used in producing the prepolymer include 4,4′-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, and xylylene diisocyanate. , Tolidine diisocyanate, p-phenylene diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, diphenylsulfone diisocyanate, etc., 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine methyl ester diisocyanate, methylene diisocyanate , Isopropylene diisocyanate, lysine diisocyanate, 1,5-octylene diisocyanate Aliphatic compounds such as dimer acid diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate, methylcyclohexane diisocyanate, 4,4′-methylenedicyclohexyl diisocyanate, hydrogenated tolylene diisocyanate, isopropylidene dicyclohexyl-4,4′-diisocyanate, and the like. Can be mentioned.

  In order to give the prepolymer fluidity at 20 to 80 ° C., amorphous 1,6-hexane diisocyanate, isphorone diisocyanate, 4,4′-methylene dicyclohexyl diisocyanate, 2,4-trimethyl at 20 to 80 ° C. Range isocyanate / 2,6-tolylene diisocyanate = 80/20 (hereinafter referred to as TDI (−80)) and the like are preferable.

  Examples of the polyether-based polyol that can be used in producing the prepolymer include polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like, as well as low-molecular polyols and glycols. And copolymers obtained by addition polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc., alone or in a known manner by a known method, but the prepolymer has fluidity at 20 to 80 ° C. In order to give it, it is preferable to use a polyol that is liquid at 20 ° C. or a composition that is liquid when mixed with the polyol.

  Examples of the short-chain glycols include ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol And aliphatic glycols such as neopentyl glycol, alicyclic glycols such as bishydroxymethylcyclohexane and cyclohexane-1,4-diol, and aromatic glycols such as xylylene glycol.

  Examples of the polycarbonate-based polyol that can be used for producing the prepolymer include polyols obtained by a condensation reaction of the short-chain glycols with a dialkyl carbonate or alkylene carbonate alone or in a mixture. In order to give fluidity at 20 to 80 ° C. to the polymer, it is preferable to use a polyol that forms a liquid at 20 ° C. or a composition that forms a liquid by mixing with the polyol.

  Examples of polyester-based polyols that can be used in producing the prepolymer include ring-opening polymerization of lactones using the polyols and glycols as initiators in addition to the condensates of the short-chain glycols and dibasic acids. And lactone-based polyols such as polylactone diol, polycaprolactone diol, and polymethylvalerolactone diol obtained by treatment. Examples of the dibasic acid include succinic acid, glutaric acid, adipic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, tartaric acid, oxalic acid, malonic acid, pimelic acid, suberic acid, glutaconic acid. , Azelaic acid, 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid and the like. However, in order to give the prepolymer fluidity at 20 to 80 ° C., it is preferable to use a polyol which is liquid at 20 ° C. or a composition which is liquid by mixing with the polyol.

  In addition, in order to accelerate the reaction in the prepolymer synthesis, conventionally known amine-based and organometallic urethane reaction catalysts can be used alone or in combination of two or more.

  The prepolymer is characterized by having a radically polymerizable unsaturated group, and the method for introducing a radically polymerizable unsaturated group is that after synthesizing a terminal hydroxyl group prepolymer, an isocyanate group and an unsaturated group are contained in the same molecule. The method of making the compound containing this react is mentioned. Examples of the compound containing an isocyanate group and an unsaturated group in the same molecule include 2-methacryloyloxyethyl isocyanate and 2-acryloyloxyethyl isocyanate. In this method, the resulting prepolymer is reacted so that hydroxyl groups remain so that crosslinking can be facilitated by a polyisocyanate crosslinking agent described later. The preferred hydroxyl value in the prepolymer is 5 to 200 mgKOH / g, more preferably 10 to 100 mgKOH / g. This is because when the hydroxyl value of the prepolymer is less than 5 mgKOH / g, the crosslinkability of the prepolymer is insufficient, whereas when the hydroxyl value exceeds 200 mgKOH / g, the strength and elongation of the resulting adhesive film are lowered.

  The presaturation equivalent of the prepolymer is required to be in the range of 4,000 to 200,000, particularly preferably 10,000 to 100,000. If the unsaturated equivalent of the prepolymer is too small, the adhesive becomes highly viscous when used as an adhesive, so that high temperature heating is required for use, and energy consumption increases, which is not preferable. On the other hand, if the unsaturated equivalent is too large, the photopolymerization due to the introduction of unsaturated groups is not sufficiently imparted, so that the base material is impregnated with the adhesive, and the object of the present invention may not be achieved.

  Even with the prepolymer alone, it is possible to bond the skin layer and the base material, but in order to give a product value as a synthetic artificial leather, a reactive monomer is added to the prepolymer to supplement the adhesive by crosslinking. It is necessary to improve the peel strength and texture of the substrate.

  As the reactive monomer used in the present invention, any polyfunctional unsaturated group-containing organic compound conventionally used in the field of photosensitive resins can be used, and a polyfunctional acrylic monomer is particularly suitable.

  Examples of polyfunctional acrylic monomers include 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, and trimethylolpropane tri (Meth) acrylate, pentaerythritol tri (meth) acrylate and derivatives thereof may be mentioned.

  The photopolymerization initiator used in the present invention is preferably one that generates radicals by light and initiates radical polymerization of unsaturated group-containing urethane polymers and polyfunctional monomers, and is a conventionally known radical reaction in the photosensitive resin field. Any type photoinitiator can be used and is not particularly limited. For example, benzophenone, acetophenone, benzoisobutyl ether, benzoin methyl ether, 2,4-dimethylthioxanthone, ethyl anthraquinone, 4,4'-bismethylaminobenzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, and the like.

  These photopolymerization initiators can be used alone or in combination of two or more according to the type of unsaturated group-containing urethane polymer and polyfunctional monomer to be used. The usage-amount of a photoinitiator is not specifically limited, Usually, it is used in the ratio of about 0.1-10 mass parts per 100 mass parts of unsaturated group containing polymers bridge | crosslinked with active energy rays, such as an ultraviolet-ray and an electron beam. .

  Depending on the purpose of use, an ultraviolet absorber, an antioxidant, a colorant, a flame retardant, inorganic fillers such as silica and alumina, and the like can be used in combination.

  Next, examples of the crosslinking agent used in the high molecular weight crosslinking reaction of the adhesive after bonding the skin layer and the substrate include polyisocyanate (including block type) crosslinking agents, melamine crosslinking agents, and epoxy crosslinking agents. Carbodiimide cross-linking agents, etc., but the cross-linking method of the coating film comprising the paint of the present invention is particularly preferably a cross-linking method using polyisocyanate utilizing reactivity with a hydroxyl group or a urethane group, and further volatilization in the atmosphere. Considering the suppression of the release of the organic material, the non-blocking type is preferable.

  As the polyisocyanate crosslinking agent, known ones that have been conventionally used can be used and are not particularly limited. From a bullet type such as HDI, TDI, and MDI, an isocyanurate type, an adduct type, and a modified liquid type, these can be used alone or in combination of two or more. The NCO content of the polyisocyanate crosslinking agent is preferably 5 to 30% by mass, particularly preferably 15 to 25%. Although the usage-amount of a polyisocyanate crosslinking agent is not specifically limited, It is preferable to use it in the ratio of about 2-30 mass parts per 100 mass parts of urethane prepolymers.

In the present invention, the active energy ray reactive adhesive composition having the above composition is coated on a polyurethane skin layer formed on a release paper, and then ultraviolet rays of 100 to 1,500 mJ / cm ² or 1 to 1 are applied. An active energy beam such as an electron beam of 10 Mrad is irradiated to cause a radical crosslinking reaction to form a film suitable for bonding to a substrate. Then, it bonds with a base material and peels from a release paper after a heat-aging process (for example, 60 degreeC / 5 days), and obtains synthetic artificial leather.

  In order to promote the crosslinking reaction with polyisocyanate, conventionally known amine-based and organometallic urethane crosslinking catalysts can be used alone or in combination of two or more.

  The synthetic artificial leather of the present invention obtained as described above is excellent in adhesion and texture to the base material of the skin layer, and in the synthesis of the urethane prepolymer, an adhesive is obtained by combining a polyol, a short-chain glycol and an isocyanate compound. It is possible to impart hydrolysis resistance, light resistance, heat resistance, gas discoloration resistance, oleic acid resistance, cold resistance, and solvent resistance to the layer, and furniture such as shoes, bags, clothing, chairs and sofas, and vehicle seats. It is suitable for manufacturing all synthetic artificial leather products.

  The coating material for forming the skin layer of the synthetic artificial leather of the present invention is not particularly limited, such as solvent-based polyurethane, aqueous polyurethane, TPU, etc., but it is possible to provide synthetic artificial leather that reduces environmental burden by combining with aqueous polyurethane or TPU. .

  Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples and comparative examples, but the present invention is not limited thereto. In the following text, “parts” and “%” are based on mass.

Example 1
100 parts of polypropylene glycol having a number average molecular weight of 2,000 (liquid at 20 ° C.), 1.5 parts of 1,4-butanediol, 5.8 parts of TDI (−80) and 0.025 part of dibutyltin dilaurate And then reacting at 105 ° C. for 3 hours, adding 1 part of 2-methacryloyloxyethyl isocyanate and further reacting at 105 ° C. for 2 hours, solid content having hydroxyl group and methacryloyl group 100%, hydroxyl value 31.4 mgKOH / G urethane prepolymer was obtained.

(Example 2)
To 100 parts of a THF-neopentyl glycol copolymer polyol (liquid at 20 ° C.) having a number average molecular weight of 1,800 and 1.5 parts of 1,4-butanediol, 6.28 parts of TDI (−80) are added, After reacting at 105 ° C. for 2 hours, 1 part of 2-methacryloyloxyethyl isocyanate was added and further reacted at 105 ° C. for 2 hours to obtain a solid content having a hydroxyl group and a methacryloyl group of 100% and a hydroxyl value of 34.1 mgKOH / g. A urethane prepolymer was obtained.

(Example 3)
To 100 parts of a THF-neopentyl glycol copolymer polyol (liquid at 20 ° C.) having a number average molecular weight of 1,800 and 1.97 parts of 1,6-hexanediol, 6.07 parts of HDI is added and reacted at 80 ° C. for 2 hours. Then, 1 part of 2-acryloyloxyethyl isocyanate was added, and the mixture was further reacted at 105 ° C. for 2 hours to obtain a urethane prepolymer having a solid content having a hydroxyl group and an acryloyl group of 100% and a hydroxyl value of 33.7 mgKOH / g. .

Example 4
1. 1,5-pentanediol having a number average molecular weight of 2,000 / 1,6-hexanediol = 50/50 (molar ratio) 100 parts of a copolycarbonate diol (liquid at 20 ° C.) and 1,4-butanediol To 5 parts, 5.8 parts of TDI (-80) was added and reacted at 105 ° C. for 1.5 hours, and then 1 part of 2-methacryloyloxyethyl isocyanate was added and further reacted at 105 ° C. for 2 hours. And a urethane prepolymer having a methacryloyl group-containing solid content of 100% and a hydroxyl value of 31.4 mgKOH / g.

(Example 5)
70 parts of a 1,5-pentanediol / 1,6-hexanediol having a number average molecular weight of 2,000 / 1,6-hexanediol = 50/50 (molar ratio) (liquid at 20 ° C.) and a number average molecular weight of 1,800 To a mixture of 30 parts of a THF-neopentylglycol copolymer polyol (liquid at 20 ° C.) and 1.5 parts of 1,4-butanediol, 5.95 parts of TDI (−80) is added, and at 105 ° C. for 1.5 hours. After the reaction, 1 part of 2-methacryloyloxyethyl isocyanate was added and further reacted at 105 ° C. for 2 hours to obtain a urethane prepolymer having a solid content of 100% having a hydroxyl group and a methacryloyl group and a hydroxyl value of 32.2 mgKOH / g. It was.

(Example 6)
70 parts of a 1,5-pentanediol / 1,6-hexanediol having a number average molecular weight of 2,000 / 1,6-hexanediol = 50/50 (molar ratio) (liquid at 20 ° C.) and a number average molecular weight of 1,800 After adding 8.54 parts of MDI to a mixture of 30 parts of THF-neopentylglycol copolymer polyol (liquid at 20 ° C.) and 1.5 parts of 1,4-butanediol, and reacting at 75 ° C. for 1.5 hours, 1 part of 2-methacryloyloxyethyl isocyanate was added, and the mixture was further reacted at 105 ° C. for 2 hours to obtain a urethane prepolymer having a hydroxyl content and a methacryloyl group of 100% solids and a hydroxyl value of 31.4 mgKOH / g.

(Example 7)
In a mixture of 100 parts of polypropylene glycol (liquid at 20 ° C.) having a number average molecular weight of 2,000 and 1.5 parts of 1,4-butanediol, 7.73 parts of TDI (−80) and 0.05 of dibutyltin dilaurate And then reacting at 105 ° C. for 4 hours, then adding 3 parts of 2-methacryloyloxyethyl isocyanate and further reacting at 105 ° C. for 2 hours, solid content having hydroxyl group and methacryloyl group 100%, hydroxyl value 12.6 mgKOH / G urethane prepolymer was obtained.

(Comparative Example 1)
To a mixture of 100 parts of a polycarbonate polyol (solid at 20 ° C.) having a glycol component of 1,6-hexanediol and a number average molecular weight of 2,000 and 1.5 parts of 1,4-butanediol, TDI (−80) After adding 5.8 parts and reacting at 105 ° C. for 1.5 hours, adding 1 part of 2-methacryloyloxyethyl isocyanate and further reacting at 105 ° C. for 2 hours, 100% solid content having a hydroxyl group and a methacryloyl group, A urethane prepolymer having a hydroxyl value of 31.4 mgKOH / g was obtained.

(Comparative Example 2)
To a mixture of 100 parts of a THF-neopentyl glycol copolymer polyol (liquid at 20 ° C.) having a number average molecular weight of 1,800 and 1.5 parts of 1,4-butanediol, 10.77 parts of TDI (−80) is added. After addition and reaction at 105 ° C. for 4 hours, 1 part of 2-methacryloyloxyethyl isocyanate was added and the reaction was further conducted at 105 ° C. for 2 hours. The solid content having a hydroxyl group and a methacryloyl group was 100%, and the hydroxyl value was 7.0 mgKOH / g. The urethane prepolymer was obtained.

(Comparative Example 3)
To a mixture of 100 parts of a THF-neopentyl glycol copolymer polyol (liquid at 20 ° C.) having a number average molecular weight of 1,800 and 1.5 parts of 1,4-butanediol, 6.28 parts of TDI (−80) is added. After addition and reaction at 105 ° C. for 2 hours, 5.5 parts of 2-methacryloyloxyethyl isocyanate was added and further reacted at 105 ° C. for 2 hours to obtain a solid content having a hydroxyl group and a methacryloyl group of 100%, a hydroxyl value of 18.2 mgKOH. / G urethane prepolymer was obtained.

(Comparative Example 4)
To a mixture of 100 parts of a THF-neopentyl glycol copolymer polyol (liquid at 20 ° C.) having a number average molecular weight of 1,800 and 1.5 parts of 1,4-butanediol, 6.28 parts of TDI (−80) is added. Then, after reacting at 105 ° C. for 2 hours, 0.08 part of 2-methacryloyloxyethyl isocyanate was added and further reacted at 105 ° C. for 2 hours to obtain a solid content having a hydroxyl group and a methacryloyl group of 100%, a hydroxyl value of 37.4 mgKOH. / G urethane prepolymer was obtained.

(Comparative Example 5)
To 100 parts of poly [(3-methyl-1,5-pentanediol) -alt- (adipic acid)] polyol (liquid at 20 ° C.) having a number average molecular weight of 500, 17.4 parts of TDI (−80) is added. After reacting at 105 ° C. for 1.5 hours, 1 part of 2-methacryloyloxyethyl isocyanate was added, and the mixture was further reacted at 105 ° C. for 2 hours. The solid content having a hydroxyl group and a methacryloyl group was 100%, and the hydroxyl value was 92.1 mgKOH / g of urethane prepolymer was obtained.

  The appearance, the viscosity at 20 ° C. and 80 ° C., the coating suitability, the number average molecular weight and the unsaturated equivalent of the urethane prepolymers obtained in the above Examples and Comparative Examples are summarized in Table 1 below.

(Application examples)
Using the adhesive obtained in the present invention, a skin layer and a base material (tricot) were bonded together to produce a synthetic leather. In addition, the skin layer was created on the following conditions using DNTP-155T-FLAT (made by Dai Nippon Printing Co., Ltd.) for the release paper.
<Preparation> Rezamin PUD-6029 SPA (water-based resin manufactured by Dainichi Seika Kogyo Co., Ltd.) 100 parts, Rezamin D-52 cross-linking agent (manufactured by Dainichi Seika Kogyo Co., Ltd.) 10 parts, D-87 thickener (Daiichi Seika Kogyo Co., Ltd.) 3 parts) <Coating amount> 150 μm / wet
<Drying conditions> 100 ° C./5 minutes <Film thickness> about 45 μm

(Application 1)
To 100 parts of the urethane prepolymer obtained in Example 7, 10 parts of trimethylolpropane triacrylate as a reactive monomer, 1 part of 2,2-dimethoxy-1,2-diphenylethane-1-one as a photopolymerization initiator, poly Adhesive with 22 parts of 24A-100 (manufactured by Asahi Kasei Chemicals) as an isocyanate crosslinking agent and 0.05 part of octylate of 1,8-diazabicyclo (5,4,0) undecene-7 as a crosslinking reaction accelerator The composition was prepared. The viscosity was 80 dPa · s at 20 ° C.

  Next, the adhesive composition was applied on the skin layer with a thickness of 100 μm, and an electron beam with a light intensity of 5 Mrad was irradiated to obtain a crosslinked coating suitable for bonding to the substrate. Next, the skin layer was bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 25 ° C.) and then aged at 60 ° C./5 days to increase the molecular weight of the adhesive composition, Synthetic leather with excellent texture was obtained.

(Application example 2)
To 100 parts of the urethane prepolymer obtained in Example 2, 8 parts of trimethylolpropane diacrylate as a reactive monomer and 0.5 parts of 2,2-dimethoxy-1,2-diphenylethane-1-one as a photopolymerization initiator Then, 20 parts of D-101 (manufactured by Asahi Kasei Chemicals Co., Ltd.) as a polyisocyanate crosslinking agent and 0.03 part of stannous octylate as a crosslinking reaction accelerator were mixed and stirred to prepare an adhesive composition. The viscosity was 80 dPa · s at 20 ° C.

Next, the adhesive composition is applied to the skin layer with a thickness of 100 μm, and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source to obtain a crosslinked coating suitable for bonding to a substrate. It was. Next, the skin layer was bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 25 ° C.) and then aged at 60 ° C./5 days to increase the molecular weight of the adhesive composition, Synthetic leather with excellent texture was obtained.

(Application 3)
To 100 parts of the urethane prepolymer obtained in Example 4, 2 parts of pentaerythritol triacrylate as a reactive monomer, 0.5 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, and 25 parts of D-101 as a polyisocyanate crosslinking agent was mixed and stirred to prepare an adhesive composition. The viscosity was 150 dPa · s at 80 ° C. Next, the adhesive composition is applied to the skin layer with a thickness of 100 μm, and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source to obtain a crosslinked coating suitable for bonding to a substrate. It was.

  Next, the skin layer was bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 25 ° C.) and then aged at 60 ° C./5 days to increase the molecular weight of the adhesive composition, Synthetic leather with excellent texture was obtained.

(Application 4)
To 100 parts of the urethane prepolymer obtained in Example 5, 4 parts of pentaerythritol triacrylate as a reactive monomer, 0.5 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, As an polyisocyanate crosslinking agent, 10 parts of D-101 and 5 parts of THA-100 (manufactured by Asahi Kasei Chemicals) were mixed and stirred to prepare an adhesive composition. The viscosity was 140 dPa · s at 80 ° C.

Next, the adhesive composition is applied to the skin layer with a thickness of 100 μm, and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source to obtain a crosslinked coating suitable for bonding to a substrate. It was. Next, the skin layer was bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 25 ° C.) and then aged at 60 ° C./5 days to increase the molecular weight of the adhesive composition, Synthetic leather with excellent texture was obtained.

(Comparative Application Example 1)
To 100 parts of the urethane prepolymer obtained in Example 4, 25 parts of D-101 as a polyisocyanate crosslinking agent and 0.5 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator Were mixed and stirred, and the reactive monomer was removed to prepare an adhesive composition. The viscosity was 160 dPa · s at 80 ° C.

Next, the adhesive composition was applied to the skin layer with a thickness of 100 μm and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source, but the film formation was insufficient. After bonding with a base material and a laminating machine (clearance 0 μm, roll temperature 25 ° C.), aging was performed at 60 ° C./5 days to increase the molecular weight of the adhesive composition, but the adhesive strength and texture were insufficient. It became synthetic leather.

(Comparative application example 2)
To 100 parts of the urethane prepolymer obtained in Example 5, 4 parts of pentaerythritol triacrylate as a reactive monomer, 0.5 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, Then, 1 part of D-101 as a polyisocyanate crosslinking agent was mixed and stirred to prepare an adhesive composition. The viscosity was 190 dPa · s at 80 ° C. Next, the adhesive composition is applied to the skin layer with a thickness of 100 μm, and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source to obtain a crosslinked coating suitable for bonding to a substrate. It was.

  Next, the skin layer was bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 25 ° C.) and then aged at 60 ° C./5 days to obtain a high molecular weight of the adhesive composition. Synthetic leather has a good texture but lacks adhesive strength.

(Comparative Application Example 3)
To 100 parts of the urethane prepolymer obtained in Comparative Example 4, 20 parts of trimethylolpropane diacrylate as a reactive monomer, 2 parts of 2,2-dimethoxy-1,2-diphenylethane-1-one as a photopolymerization initiator, poly An adhesive composition was prepared by mixing and stirring 20 parts of D-101 as an isocyanate crosslinking agent and 0.03 part of stannous octylate as a crosslinking reaction accelerator. The viscosity was 60 dPa · s at 20 ° C.

Next, the adhesive composition was applied on the skin layer to a thickness of 100 μm, and irradiated with ultraviolet rays using a metal halide lamp having a light amount of 390 mj / cm ² as a light source, but a hard coating containing a fluid resin was obtained. After bonding with a base material and a laminating machine (clearance 0 μm, roll temperature 25 ° C.), aging was performed at 60 ° C./5 days to increase the molecular weight of the adhesive composition, but the adhesive strength and texture were insufficient. It became synthetic leather.

(Comparative Application Example 4)
To 100 parts of the urethane prepolymer obtained in Comparative Example 5, 5 parts of pentaerythritol triacrylate as a reactive monomer, 0.5 part of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, 15 parts of THA-100 as a polyisocyanate crosslinking agent was mixed and stirred to prepare an adhesive composition. The viscosity was 30 dPa · s at 20 ° C.

Next, the adhesive composition was applied to the skin layer with a thickness of 100 μm, but a liquid flow phenomenon occurred and a uniform coating film could not be obtained. After irradiating ultraviolet rays using a metal halide lamp with a light amount of 390 mj / cm ² as a light source, the substrate and a laminating machine (clearance 0 μm, roll temperature 25 ° C.) are bonded and aged for 60 ° C./5 days, and the adhesive composition The synthetic leather obtained by increasing the molecular weight of the product was a defective product with a non-adhered portion although the texture was good.

(Reference example)
The skin layer and the base material (tricot) were bonded together using a solvent-type adhesive to produce a synthetic artificial leather. In addition, the skin layer was created on the following conditions using DNTP-155T-FLAT (made by Dai Nippon Printing Co., Ltd.) for the release paper.
<Preparation> Resamine ME-8106 (manufactured by Dainichi Seika Kogyo Co., Ltd. 70% solvent) 100 parts, 33 parts DMF <application amount> 200 μm / wet
<Drying conditions> 100 ° C./5 minutes <Film thickness> about 45 μm

(Reference Example 1)
Resamine UD-8358D (manufactured by Dainichi Seika Kogyo Co., Ltd., 42% solvent) 100 parts of Resamine UD-crosslinking agent (Daiichi Seika Kogyo Co., Ltd.), UD-103 accelerator (Daiichi Seika Kogyo) 5 parts were mixed and stirred to prepare a solvent-based adhesive compounding solution. Next, the adhesive composition was applied onto the skin layer at 200 μm / wet and dried at 100 ° C./90 seconds to form an adhesive layer of about 100 μm. Next, the skin layer is bonded to the base material with a laminating machine (clearance 0 μm, roll temperature 120 ° C.) and then aged at 60 ° C. for 5 days to increase the molecular weight of the adhesive composition and to make a known synthesis. Leather was produced. When the adhesive strength and texture of the environmentally friendly synthetic leather obtained in the present invention were compared with those of the leather, the results were equivalent. The evaluation results are shown in Tables 3 and 4 below.

  According to the present invention, energy consumption required for evaporative removal is reduced without using an organic solvent or water, and further, energy consumption required for heating is reduced by handling at 20 ° C. to 80 ° C. It is possible to provide a synthetic artificial leather using an environmentally friendly adhesive that hardly emits volatile organic substances to the substrate, a method for producing the same, and the like.

Claims (10)

  It consists of a base material, an adhesive layer, and a skin layer, and the adhesive layer contains a radical polymerizable unsaturated group and a hydroxyl group, and the unsaturated equivalent of the radical polymerizable unsaturated group is 4,000 to 200. A synthetic artificial leather comprising a photopolymerizable urethane prepolymer having a molecular weight of 1,000.   The synthetic artificial leather according to claim 1, wherein the urethane prepolymer is substantially 100% non-volatile and liquid at 20 to 80 ° C.   The synthetic artificial leather according to claim 2, wherein the urethane prepolymer has a hydroxyl value of 5 to 200 mgKOH / g.   The synthetic artificial leather according to claim 3, wherein the radical polymerizable unsaturated group is derived from an isocyanate group-containing (meth) acrylate.   The adhesive is 0.5 to 50 parts by mass of a polyfunctional unsaturated group-containing reactive monomer, 0.1 to 10 parts by mass of a photopolymerization initiator, and NCO with respect to 100 parts by mass of the urethane prepolymer according to claim 3. The synthetic artificial leather according to claim 4, comprising 2 to 30 parts by mass of a polyisocyanate crosslinking agent having a content of 5 to 30% by mass.   The adhesive according to claim 5 is applied to the surface of the skin layer (the surface opposite to the surface in contact with the release paper), the adhesive is cured with active energy rays, and then the surface of the adhesive layer is A method for producing a synthetic artificial leather, comprising laminating materials and heat aging to crosslink and cure the adhesive.   A photopolymerizable urethane prepolymer comprising a radical polymerizable unsaturated group and a hydroxyl group, wherein the unsaturated equivalent of the radical polymerizable unsaturated group is from 4,000 to 200,000.   The photopolymerizable urethane prepolymer according to claim 7, wherein the urethane prepolymer is substantially 100% non-volatile and is liquid at 20 to 80 ° C.   The photopolymerizable urethane prepolymer according to claim 8, wherein the radically polymerizable unsaturated group is derived from an isocyanate group-containing (meth) acrylate.   Polyfunctional unsaturated group containing reactive monomer 0.5-50 mass part with respect to 100 mass parts of urethane prepolymers of any one of Claims 7-9, 0.1-10 mass of photoinitiators. An adhesive composition comprising 2 to 30 parts by mass of a polyisocyanate crosslinking agent having an NCO content of 5 to 30% by mass.