JP2014231645A - Artificial leather paste, and artificial leather sheet and repair material including the same - Google Patents

Abstract

It is an object of the present invention to provide a natural leather-like synthetic leather paste, and a synthetic leather sheet and a repair material using the same. A synthetic leather paste comprising collagen, a polyurethane resin having at least one siloxane bond, and an aqueous solvent. [Selection figure] None

Description

  The present invention relates to a synthetic leather paste. More particularly, the present invention relates to a natural leather-like synthetic leather paste.

  Conventionally, natural leather obtained by processing animal skin has been used for shoes, bags, car seats, interior products, and the like. However, since natural leather is expensive, synthetic leather has been developed as an alternative. Synthetic leather is obtained by impregnating or applying synthetic resin to a natural fabric or an artificial fabric such as a nonwoven fabric. Conventionally, synthetic leather was manufactured using only synthetic resins such as polyvinyl chloride and polyurethane, but the texture, appearance, flexibility and the like were clearly different from those of natural leather. Thus, research has been conducted on natural leather-like synthetic leather that has a texture close to that of natural leather.

  As a method for producing natural leather-like synthetic leather, a method of adding collagen powder to a synthetic resin has been proposed. For example, Patent Document 1 discloses a synthetic leather containing collagen having a fiber structure inside a synthetic resin.

JP-A-6-17378

  Collagen having a fiber structure contained in the synthetic leather described in Patent Document 1 has a structure similar to that of a collagen fiber that forms a three-dimensionally entangled tissue contained in natural leather, so the texture is similar to that of natural leather. To do. However, since the collagen contained in the synthetic leather of Patent Document 1 is one in which collagen powder is fiberized in the stagnation process, its size is very small compared to collagen fibers contained in natural leather, and the fiber structure is also It's simple. Therefore, it cannot be said that the collagen fibers that form the three-dimensionally entangled tissue of natural leather are sufficiently reproduced, and the synthetic leather having this structure has a natural leather-like texture, appearance, flexibility, etc. It was not realized. Therefore, an object of the present invention is to provide means capable of realizing a natural leather-like texture, appearance, flexibility and the like in synthetic leather.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by using a specific polyurethane resin, and have completed the present invention.

  That is, the present invention provides a synthetic leather paste containing an aqueous solvent together with collagen and a polyurethane resin having at least one siloxane bond, and a synthetic leather sheet and a repair material using the same.

  According to the present invention, a natural leather-like synthetic leather paste, and synthetic leather and a repair material using the same are provided. According to the present invention, by using a specific polyurethane resin, collagen can be contained in the polyurethane resin. As a result, a natural leather-like texture, appearance, flexibility and the like can be realized.

  Embodiments of the present invention will be described below.

[Synthetic leather paste]
According to an embodiment of the present invention, a natural leather-like synthetic leather paste may be provided. The synthetic leather paste includes collagen, a polyurethane resin having at least one siloxane bond, and an aqueous solvent.

  According to this embodiment, the polyurethane resin contains at least one siloxane bond, whereby collagen can be contained in the polyurethane resin. Thereby, it is possible to contain not only the conventional collagen powder and the collagen in which this is fibrillated during the production process, but also collagen fibers having a large size and forming a three-dimensionally entangled tissue. For this reason, since the synthetic leather paste which concerns on this form contains the collagen fiber which has a structure equivalent to the collagen fiber contained in natural leather, it can implement | achieve natural leather-like texture, an external appearance, a softness | flexibility, etc.

(collagen)
When collagen is contained in synthetic leather, natural leather-like synthetic leather can be obtained. Generally, collagen is highly hydrophilic and swells by absorbing water. Such water absorption of collagen is related to the water resistance, hygroscopicity, flexibility and the like of synthetic leather, and thus has a great influence on the characteristics of synthetic leather. The action of the collagen with water, that is, moisture absorption and desorption, can be affected by the structure of the collagen. For example, when collagen has a fiber structure, it exhibits a moisture absorption and release property because it exhibits capillary action. Collagen has hydrophilic groups such as a hydroxyl group, an amino group, and a carboxyl group, and these interact with each other so that water is transferred between collagen molecules. The collagen fibers that are large in size and form a three-dimensionally entangled tissue have a triple-stranded helical structure consisting of repeating three amino acid sequences of glycine-proline-hydroxyproline called collagen helix. It is presumed that the collagen helix facilitates intermolecular interaction due to the hydrophilic group.

  As described above, collagen fibers having a large size and a structure that forms a three-dimensionally entangled tissue are highly related to the characteristics of natural leather. If this collagen fiber can be contained in the synthetic leather, synthetic leather similar to natural leather should be manufactured.

  However, the solvent used in the production of synthetic leather is usually an aqueous solvent. Therefore, when the collagen fiber is to be contained in the synthetic resin in the aqueous solvent, the collagen fiber swells with water and is eluted from the synthetic resin. For this reason, it is not possible to use large-sized collagen fibers, and it is necessary to pulverize collagen into a synthetic resin as in Patent Document 1. As described above, even if collagen powder is fibrillated by the stagnation process, its size is very small and the fiber structure is simple. Therefore, the fiber structure of fiberized collagen obtained from collagen powder is greatly different from the fiber structure of collagen fibers contained in natural leather. Therefore, although it can be said that it is similar to natural leather compared to synthetic leather consisting only of synthetic resin, it does not sufficiently realize its texture, appearance, flexibility, etc. compared to actual natural leather.

  According to this embodiment, collagen fibers that are large in size and form a three-dimensionally entangled tissue can be contained, so that the synthetic leather contains the collagen fibers to achieve a natural leather-like texture, etc. can do.

  Collagen that can be used in this form is not particularly limited. For example, collagen contained in tissues such as skins, bones, and tendons of animals such as cows, horses, pigs, and sheep can be used. Moreover, you may use the collagen contained in shaving wastes, such as chrome leather shaving waste, cutting waste, inferior goods, etc. which are the wastes produced in the manufacturing process of natural leather. Further, gelatin obtained by denaturing collagen may be used instead of or together with the collagen. Among these, from the viewpoint of providing natural leather-like synthetic leather, it is preferable to use collagen used in natural leather, that is, waste produced in the production process of animal skin or natural leather, from the viewpoint of environmental considerations. It is more preferable to use waste generated in the natural leather manufacturing process. The chrome leather shaving waste is shaving waste generated after chrome tanning in the production process of natural leather, and contains chromium together with collagen. Chrome leather shaving waste can be used as it is as collagen in this form, but considering that trivalent chromium contained in chromium leather shaving waste may be converted to hexavalent chromium harmful to the human body, It is preferable to use purified collagen that has been removed. The said purification method is not specifically limited, For example, it can carry out by the method of repeating an alkali treatment and an acid treatment, the method of performing a hydrogen peroxide treatment, and these combination.

  The shape of collagen that can be used in the present embodiment is not particularly limited, and may be fiberized, powdered, or other shapes. Among these, from the viewpoint of providing a natural leather-like synthetic leather, it is preferable to use collagen fibers in which a three-dimensionally entangled tissue is formed.

  The size of the collagen that can be used in this form is not particularly limited. However, since the fiber structure of the collagen affects the moisture absorption and release characteristics of the leather, collagen that is not powdered and that is as large as possible is used. It is preferable to use it. In this specification, the size of collagen is defined by “collagen length”, and “collagen length” is an average value obtained by taking 200 collagens in a synthetic leather paste and measuring the maximum width of collagen. Means. For example, when the collagen is in the form of a fiber bundle, the length of the collagen is an average value obtained by measuring the lengths of 200 collagens in the long axis direction. The length of the collagen that can be used in this embodiment is preferably 100 to 1000 μm, and more preferably 200 to 500 μm. In addition, the length of the powdered collagen conventionally used is 50 micrometers or less normally.

  The content of collagen contained in the synthetic leather paste is not particularly limited, but is preferably 10 to 80% by mass and more preferably 50 to 70% by mass with respect to the total mass of the synthetic leather paste. . A collagen content of 10% by mass or more is preferred because a natural leather-like synthetic leather paste can be obtained. On the other hand, when the collagen content is 80% by mass or less, it is preferable because excessive swelling of collagen can be prevented.

(Polyurethane resin)
The polyurethane resin has at least one siloxane bond and can incorporate collagen into the polyurethane resin. As a result, the contact between collagen and water in water is suppressed, so that collagen does not swell and elution of collagen from the inside of the synthetic resin can be suppressed. Moreover, it becomes the polyurethane resin which has a network structure by a siloxane bond, and can take in collagen firmly.

  The polyurethane resin that can be used in this embodiment is not particularly limited as long as it has at least one siloxane bond, and any polyurethane resin can be used. In addition, the polyurethane resin having at least one siloxane bond may be derived from a polyurethane resin having at least one silanol group, specifically, a polyurethane resin having at least one silanol group and a strong resin. It can be derived from an aqueous polyurethane resin composition containing a basic tertiary amine. The strongly basic tertiary amine contained in the water-based polyurethane resin composition causes a dehydration condensation reaction of the silanol group due to catalytic action with the silanol group of the polyurethane resin that is stably present in water. Part or all of them form a siloxane bond. When all of the silanol groups of the polyurethane resin having at least one silanol group do not form a siloxane bond, the synthetic leather paste contains a polyurethane resin having a silanol group together with the siloxane bond. It shall be included in the technical idea. In the present invention, it is preferable to obtain a polyurethane resin having at least one siloxane bond by inducing a siloxane bond from a part of the silanol group of the aqueous polyurethane resin composition. The reason for this is that according to the polyurethane resin, the remaining silanol groups further form collagen by forming covalent bonds or non-covalent bonds with hydrophilic groups such as hydroxyl groups, amino groups, and carboxyl groups in the collagen molecule. It is because it can be stably contained in the polyurethane resin.

  As the water-based polyurethane resin composition, commercially available products can be used. For example, Takelac W-405, W-605, W-615, WS-4000, WS-5000, WS-5100, W-6010, W-6020, WS-6021 (manufactured by Mitsui Chemicals, Inc.) and the like are commercially available.

  The aqueous polyurethane resin composition may be produced by mixing a polyurethane resin having at least one silanol group and a strongly basic tertiary amine in an aqueous solvent.

  As the polyurethane resin having at least one silanol group, a known resin can be used. For example, (1) a compound having at least two active hydrogens in the molecule, (2) a compound having at least two isocyanate groups in the molecule, and (3) an activity capable of reacting with at least one isocyanate group in the molecule. A polyurethane resin having at least one silanol group obtained by reacting hydrogen and a compound containing a hydrolyzable silicon group can be used.

  As the compound (1) having at least two active hydrogens in the molecule, compounds having active hydrogens such as a hydroxyl group, an amino group, and a thiol group can be used. Among these, it is preferable to use polyester polyol, polyether polyol, polyether ester polyol, polyester amide polyol, acrylic polyol, polycarbonate polyol, polyhydroxyl alkane, castor oil, polyurethane polyol, or a mixture thereof. JP-A-9-12864 can be referred to for specific examples of the above compound.

  Examples of the compound (2) having at least two isocyanate groups in the molecule include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, araliphatic diisocyanates, polyisocyanate monomers, dimers derived therefrom, and Trimer, biuret, compound having allophanate bond, polyisocyanate having 2,4,6-oxadiazinetrione ring obtained from carbon dioxide gas and polyisocyanate monomer, polyisocyanate having low molecular weight less than 200 Monomer adducts, polyester polyols, polyether polyols, polyether ester polyols, polyester amide polyols, polycaprolactone polyols, polyvalerolactone polyols, Le polyols, polycarbonate polyols, hydroxyl alkane, castor oil, and said polyisocyanate monomer adduct such as polyurethane polyols, etc. can be used. JP-A-9-12864 can be referred to for specific examples of the above compound.

  The compound containing (3) active hydrogen capable of reacting with at least one isocyanate group in the molecule and a hydrolyzable silicon group includes the active hydrogen and a hydrolyzable group (hydrogen atom, halogen atom, alkoxy group, An acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a thiol group, an alkenyloxy group, etc.) having a hydrolyzable silicon group formed by bonding to a silicon atom can be used. JP-A-9-12864 can be referred to for specific examples of the above compound.

  Moreover, a well-known thing can be used for the strongly basic tertiary amine contained in an aqueous polyurethane resin composition. At this time, the siloxane bond forming reaction described above varies depending on the basic strength of the strong basic tertiary amine used, and the siloxane forming reaction can proceed more strongly with a strong base. Therefore, from the viewpoint of forming a siloxane bond, the strongly basic tertiary amine is preferably a tertiary amine having a pKa of 11 or more, and 1,8-diazabicyclo [5.4.0] undec-7 More preferred is -ene (DBU) or 1,5-diazabicyclo [4.3.0] non-5-ene (DBN). The strong basic tertiary amine may be used alone or in combination of two or more. The content of the strongly basic tertiary amine contained in the aqueous polyurethane resin composition is 0.001 to 10 masses with respect to 100 mass parts of the polyurethane resin having at least one silanol group from the viewpoint of forming a siloxane bond. Part is preferably included.

  The above polyurethane resin having at least one siloxane bond and the aqueous polyurethane resin composition may be used alone or in combination of two or more.

  The content of the polyurethane resin having at least one siloxane bond contained in the synthetic leather paste is not particularly limited, but is preferably 5 to 50% by mass with respect to the total mass of the synthetic leather paste, and 10 to 30 More preferably, it is mass%. When the content of the polyurethane resin is 5% by mass or more, collagen elution can be suppressed, which is preferable. On the other hand, when the content of the polyurethane resin is 50% by mass or less, the content of collagen relative to the synthetic leather paste is not excessively low, and a natural leather-like synthetic leather paste is obtained.

(Aqueous solvent)
When the synthetic leather paste according to the present embodiment contains an aqueous solvent, a paste-like synthetic leather, that is, a synthetic leather paste can be obtained.

  The aqueous solvent of this embodiment is usually derived from the solvent contained in the above-mentioned aqueous polyurethane resin composition and the solvent contained in collagen, and the solvent is water or a mixed solvent of water and an organic solvent. . The organic solvent is not particularly limited as long as it is miscible with water; monoalcohols such as methanol, ethanol, propyl alcohol, isopropyl alcohol, and butanol; ketones such as acetone; ethylene glycol, diethylene glycol, triethylene glycol , Propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, hexylene glycol, glycerin, diglycerin, tetralin and other polyhydric alcohols; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Examples include ethers such as cetate, ethylene glycol monophenyl ether, and propylene glycol monophenyl ether; nitriles such as acetonitrile; dimethyl sulfoxide (DMSO); and aqueous high-boiling solvents such as N-methyl-2-pyrrolidone and 2-pyrrolidone. . The said organic solvent may be used independently and may be used in mixture of 2 or more types.

  As the aqueous solvent, it is preferable to use only water from the viewpoint of environmental consideration.

  The content of the aqueous solvent contained in the synthetic leather paste is not particularly limited, but is preferably 0.5 to 15% by mass, and 5 to 8% by mass with respect to the total mass of the synthetic leather paste. Is more preferable. When the content of the aqueous solvent is 0.5% by mass or more, the viscosity of the synthetic leather paste does not become too high, and the handling becomes easy. On the other hand, it is preferable that the content of the aqueous solvent is 15% by mass or less because the viscosity of the synthetic leather paste does not become too low and the handling becomes easy.

(Additive)
The synthetic leather paste according to this embodiment may further contain an additive as necessary. Examples of the additive include a crosslinking agent and a greasing agent.

Crosslinking agent The crosslinking agent reacts with the polyurethane resin and / or collagen to form a crosslink. Water resistance can be imparted by crosslinking of the polyurethane resin. The polyurethane resin may be deteriorated by water because the urethane bond is hydrolyzed. Therefore, water resistance can be imparted by forming a crosslink with an epoxy resin. In addition, since the above-mentioned commercially available water-based polyurethane resin composition has a self-crosslinking property, the synthetic leather paste obtained using the water-based polyurethane resin composition has a certain water resistance without adding an epoxy resin. Can be granted. However, it is preferable to add an epoxy resin in order to impart higher durability. On the other hand, since collagen swells with water, the collagen helix may dissociate due to swelling. Therefore, by cross-linking collagen, the fiber structure can be stabilized, and the hygroscopic property of the synthetic leather paste can be maintained. Further, by crosslinking the collagen, the collagen becomes soft and plasticity can be imparted to the synthetic leather paste.

  The cross-linking agent that can be used is not particularly limited, but a water-soluble cross-linking agent is preferably used from the viewpoint of forming a cross-link with collagen. Examples of water-soluble crosslinking agents include epoxy resins and aldehyde resins. Of these, it is particularly preferable to use an epoxy resin. The epoxy resin is not particularly limited, and known ones can be used. Examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, and modified epoxy resin. Of these, alicyclic epoxy resins are preferably used. Examples of the alicyclic epoxy resins include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, and diglycerol polyglycidyl ether. Glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl Examples include ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. The said epoxy resin may be used independently, or 2 or more types may be mixed and used for it. Moreover, the epoxy resin which has 2 or more of epoxy groups from a viewpoint which forms bridge | crosslinking highly and provides durability and plasticity is preferable. Epoxy resins that can be used may be commercially available, for example, Denacol Ex-321, Ex-411, Ex-421, Ex-512, Ex-521, Ex-611, Ex-614, Ex -614B, Ex-622, Ex-821, Ex-830, Ex-832, Ex-841 (manufactured by Nagase ChemteX Corporation) and the like can be used. The said epoxy resin may be used independently and may be used in mixture of 2 or more types.

  According to another embodiment of the present invention, an epoxy resin that is not bonded to a carboxyl group of the polyurethane resin in the synthetic leather can give the synthetic leather flexibility. Although details regarding the provision of flexibility are not clear, for example, the flexibility of the epoxy resin itself present in the synthetic leather alone or by crosslinking or interacting with collagen is directly reflected in the synthetic leather. The mechanism is estimated. In addition, even if the actual mechanism is different from the above description, it is included in the technical idea of the present invention.

  According to the above estimation mechanism, it is sufficient that the epoxy resin is present alone or in a state that exhibits some action with collagen. Therefore, the synthetic leather paste of this embodiment does not necessarily include at least one siloxane bond as described above. It is not necessary to include a polyurethane resin and / or collagen fibers having That is, for example, the technical idea can be applied to the synthetic leather described in Patent Document 1.

  According to the presumed mechanism as described above, it can be expected that the epoxy resin existing in a state of forming a crosslink with the polyurethane resin is not involved in imparting the flexibility of the synthetic leather. Therefore, in order to impart flexibility, the epoxy resin is added in an amount that can exceed the crosslinking reaction of the polyurethane resin, that is, an epoxy resin that does not form a crosslinking with the polyurethane resin in the synthetic leather paste. It is necessary to Usually, since the crosslinking reaction between the polyurethane resin and the epoxy resin is caused by the reaction between the carboxyl group and the epoxy group, the amount of the epoxy resin that can be added can be determined based on the number of moles of the two functional groups. That is, in the synthetic leather paste of this embodiment, the epoxy group of the epoxy resin is present in a larger number of moles than the carboxyl group of the polyurethane resin, and at least one of the epoxy groups is bonded to the carboxyl group. Here, in contrast of the number of moles of the epoxy group and the carboxyl group in the synthetic leather paste, the epoxy group and the carboxyl group are not limited to those existing alone, and the epoxy group and the carboxyl group derived by forming a bridge are not included. Shall be included. Taking an epoxy group as an example, the number of moles of epoxy groups is calculated by including the number of epoxy groups present alone and the epoxy groups formed by a crosslinking reaction with polyurethane resin and / or collagen. Is done. In other words, the epoxy group before crosslinking may be contained in a larger number of moles than the carboxyl group contained in the polyurethane resin. When the epoxy resin is contained in the number of moles, at least 1 mole of epoxy resin having an epoxy group that is free or cross-linked with collagen is included in the synthetic leather paste, and the synthetic leather paste is flexible by the epoxy resin. Can be given.

  The epoxy resin that can be used in this embodiment is not particularly limited as long as it has flexibility. The flexibility can usually depend on the number of single bonds that the epoxy resin has. Accordingly, it is preferable to use an epoxy resin containing a large number of straight or branched single bonds, and specifically, it is preferable to use a polyglycidyl ether epoxy resin. Examples of the polyglycidyl ether-based epoxy resin include commercially available Denacol Ex-512, Ex-521, Ex-821, Ex-830, Ex-832, Ex-841 (manufactured by Nagase ChemteX Corporation). . The said epoxy resin may be used independently and may be used in mixture of 2 or more types.

  The number of moles of the carboxyl group and epoxy group can be determined by calculation. For example, the number of moles of carboxyl groups contained in the water-based polyurethane resin can be determined by the number of carboxyl groups that the prepolymer of the polyurethane resin has and the weight ratio of the prepolymer to the polyurethane resin. Moreover, the epoxy group contained in an epoxy resin can be calculated | required similarly. Information disclosed as information on commercially available products may be referred to. For example, since it is disclosed that the epoxy equivalent (molecular weight per epoxy group) of Denacol Ex-830 is 268, the epoxy equivalent From the above, the number of moles of epoxy groups contained in the epoxy resin can be calculated.

  When two or more of the above epoxy resins are used as a mixture, the epoxy resin that contributes to flexibility is present in the synthetic leather paste in a state in which no crosslink is formed via the polyurethane resin and the epoxy group. It must be added in an amount that is possible.

Greasing Agents Greasing agents have the effect of imparting flexibility to synthetic leather by filling inside collagen fibers or adhering to the surface. By using a greasing agent, it is possible to prevent the collagen fibers from hardening even when the synthetic leather is dried.

  The greasing agent that can be used is not particularly limited, and a known greasing agent can be used. However, considering that it acts on collagen, it is preferable to use a hydrophilic greasing agent. Examples of greasing agents that can be used include refined raw oils and synthetic resins, such as vegetable oils such as wood oils; semi-drying oils such as rapeseed oil, corn oil, sunflower oil, and soybean oil. Non-drying oils such as olive oil, castor oil and peanut oil; vegetable fats such as coconut fat, palm kernel fat and palm oil; fish oil such as herring oil and sardine oil; liver oil such as cod liver oil and shark liver oil; Terrestrial animal oils; animal fats such as beef tallow, sheep fat, lard, milk fat, bone fat; vegetable waxes (wax) such as nauba wax, candelilla wax, montan wax; bees wax, wool fat (wool grease), etc. Animal wax (wax): non-living fatty substances such as paraffin wax, mineral oil, olefin, synthetic hydrocarbon, synthetic fatty acid ester, higher alcohol, alkylbenzene Etc. The.

[Synthetic leather sheet]
According to one embodiment of the present invention, a synthetic leather sheet can be formed by using the synthetic leather paste described above. Since the synthetic leather sheet is large in size and can contain collagen fibers forming a three-dimensionally entangled tissue, it can have natural leather-like characteristics.

  The synthetic leather paste according to this embodiment can be formed on a base material by a known method to produce a synthetic leather sheet. The method for producing the synthetic leather sheet can be produced, for example, by foaming a synthetic leather paste and then molding the obtained foam paste on a substrate.

(Base material)
The base material supports the synthetic leather paste. As the base material that can be used, natural fabrics or artificial fabrics, specifically, synthetic resin films, woven fabrics, nonwoven fabrics, knitted fabrics made of polyethylene, polypropylene, nylon, (meth) acrylic, polyethylene terephthalate, polyethylene naphthalate, etc. Examples thereof include cloth, paper, synthetic paper, glass material, and metal material.

(Foaming agent)
The foaming agent is added when a synthetic leather sheet is produced from the synthetic leather paste. By foaming the synthetic leather paste, flexibility and heat insulation can be imparted to the polyurethane resin having at least one siloxane bond.

  There is no restriction | limiting in particular as a foaming agent which can be used, A well-known foaming agent can be used. For example, thermal decomposable blowing agents such as azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), p, p'-oxybisbenzenesulfonyl hydrazide (OBSH), p-toluenesulfonyl hydrazide (TSH), and butane In addition, volatile blowing agents such as lower alkanes such as pentane, halogenated hydrocarbons, carbon dioxide gas, and nitrogen gas can be used. The said foaming agent may be used independently, or 2 or more types may be mixed and used for it.

  The foaming agent is added in an amount of 3 to 20 parts by mass, preferably 10 to 15 parts by mass, with respect to 100 parts by mass of the synthetic leather paste.

[Repair materials]
According to an embodiment of the present invention, a repair material including the above-described synthetic leather paste can be obtained. The use as the repair material utilizes the high affinity between collagens, and the synthetic leather paste described above contains collagen fibers similar to natural leather. In the present specification, “repair” is a concept that includes repair as a homogenization of natural leather and repair of a wound of a product containing collagen.

  The homogenization of the natural leather means that the flow of natural leather fibers is made uniform. Since natural leather is made from animal skin, the density of the fibers varies depending on the part of the animal skin. Due to such a difference in fiber density, wrinkles are likely to occur when natural leather is used. Therefore, the generation of the wrinkles can be prevented by making the fiber density uniform with a repair material containing collagen by utilizing the high affinity between collagens. Since the repair material including the synthetic leather paste according to the present invention includes collagen fibers similar to natural leather, the fibers can be more effectively uniformized.

  Moreover, the repair of the wound of the said product containing collagen means repairing and repairing the damage | wound produced in the product containing collagen with a repair material. As described above, collagen has a high affinity, and since it contains collagen fibers similar to natural leather, it is easy to be familiar with a wound produced in a product containing collagen, and the wound can be suitably repaired.

  As the repair material according to this embodiment, the synthetic leather paste may be used as it is as the repair material, or a repair material may be manufactured by appropriately mixing known additives.

[Production method of synthetic leather paste]
According to one embodiment of the present invention, a method for producing a synthetic leather paste with a low production cost is provided. In the conventional synthetic leather manufacturing method, the collagen powder to be contained in the synthetic leather needs to be fine (about 50 μm or less), and therefore, a hydrolysis step and a plurality of pulverization steps of collagen fibers are necessary, and further obtained. Care was also required in handling the collagen powder. However, according to this embodiment, since collagen fibers having a large size can be used, the preparation of collagen fibers contained in the synthetic leather paste is facilitated. Therefore, in the method for producing the synthetic leather paste, the collagen pulverization step is easy and the hydrolysis step is not required, resulting in low production costs. In view of the above characteristics, in the manufacturing method according to this embodiment, collagen fibers, particularly collagen pulverized material having a length of 100 to 1000 μm is used. In addition, the length of the said collagen fiber is the average value which took 200 collagen fibers and measured the maximum width | variety of collagen like the above. Therefore, the production method of this embodiment includes a step of pulverizing collagen to obtain a collagen pulverized product having a length of 100 to 1000 μm, and a step of mixing an aqueous polyurethane resin having at least one siloxane bond with the collagen pulverized product. Including.

  When collagen obtained by dechromating chrome leather shaving waste generated during the production of natural leather is used as the collagen used in the manufacturing process, the previously discarded chrome leather shaving waste is reused. This is more preferable from the viewpoint of environmental considerations. Therefore, in the manufacturing method of this form, it is preferable to further include the step of dechromating chrome leather shaving waste generated during the production of natural leather to obtain the collagen.

  Hereinafter, each step will be described in detail.

(1) Step of dechromating chrome leather shaving waste This step is an optional step when chrome leather shaving waste is used as a collagen raw material. When using chrome leather shaving waste as a raw material, it is preferable to purify collagen by removing chrome leather by this step.

  As described above, this step can be performed by, for example, a method of repeating alkali treatment and acid treatment, a method of performing hydrogen peroxide treatment, and a combination thereof.

  The method of repeating alkali treatment and acid treatment utilizes the property that the structure of collagen fibers changes depending on the liquidity, in which the fiber structure loosens in a basic solvent and the fiber structure loosened in an acidic solvent returns. . When the fiber structure is loosened, the chromium adhering to the collagen by chrome tanning is separated from the collagen, and the chromium can be removed by washing. And the loose fiber structure can be restored even in an acidic solvent. By repeating the base treatment and the acid treatment, chromium adhering to any part of the collagen fiber can be removed.

  The basic solvent used is not particularly limited and is sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, magnesium hydroxide, copper hydroxide (II), aluminum hydroxide, iron hydroxide (III). An aqueous solution in which a base such as the above is dissolved is exemplified. On the other hand, examples of acidic solvents that can be used include aqueous solutions in which acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, carbonic acid, and oxalic acid are dissolved.

  In the method of performing the hydrogen peroxide treatment, chromium cross-linked with collagen by chrome tanning can be removed by the hydrogen peroxide treatment. In the hydrogen peroxide treatment, trivalent chromium cross-linked with collagen is converted into water-soluble hexavalent chromium, so that the chromium can be removed by washing with water.

  The method of repeating the alkali treatment and the acid treatment and the method of performing the hydrogen peroxide treatment may be carried out by only one method or a combination of both methods. From the viewpoint of effectively removing both chromium, it is preferable to carry out both methods.

  The effects of the present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[Example 1]
(Preparation of collagen)
As a collagen raw material, chrome leather shaving waste obtained from a plurality of lots in the natural leather manufacturing process was used.

  First, the chrome leather shaving waste was stored in a sealed state for one month to make the moisture content uniform. Next, the chrome leather shaving waste having a uniform moisture content was taken, and 10 times the amount of water of the chrome leather shaving waste was added. Then, 0.1% of Silastol R687 (manufactured by Schill Seillacher GmbH), which is a nonionic surfactant, was added and stirred slowly at 30 ° C. for 1 hour.

  10% by mass of chrome leather shaving scraps obtained by collecting slaked lime (calcium hydroxide) was added to the solution, and stirring and leaving every 6 hours were repeated at room temperature for 2 days to swell and loosen the collagen fibers. Next, the liquid containing chrome is removed using 300 mesh, and the obtained solid content is added to 10 times the amount of chrome leather shaving waste collected and stirred for 15 minutes at 15 to 20 ° C. for washing. did. After washing, the liquid was removed again with 300 mesh.

  In order to remove the added slaked lime, the obtained solid content is mixed with 10 times the amount of collected chrome leather shaving waste, and 2.5% by mass of the chrome leather shaving waste collected in the water is chlorinated. The ammonium was dissolved and stirred slowly at 15-20 ° C. for 20 minutes. In the same manner as described above, the obtained mixture was subjected to removal of liquid content by 300 mesh, washing with 10 times the amount of collected chrome leather shaving waste, and solid content from which slaked lime was removed by removal of liquid content by 300 mesh. Got.

  Next, in order to return the collagen fibers loosened by the acid treatment, water of 2.5 times the solid content is added to the obtained solid content, and further 80% concentrated sulfuric acid of 3 to 4% by mass of the solid content. An aqueous solution was added. Stirring and standing every 30 minutes were repeated for 1 hour at room temperature. The liquid component was removed using 100 mesh, and the stirring washing and the liquid component removal using 10 times the amount of water of the solid content were repeated twice.

  The collagen fiber structure was loosened again with a strong base. To the obtained solid content, 10 times as much water as the solid content was added, and 0.4 to 0.5 mass% sodium hydroxide of the solid content was added as a strong base. Stirring and standing every 15 minutes was repeated for 1 hour at room temperature to swell and loosen the collagen fibers. The liquid component was removed using 100 mesh, and the stirring and washing using the water of 3 times the solid content and the liquid component were repeated three times.

  The chromium that could not be removed by the base treatment was removed by converting trivalent chromium to hexavalent chromium by hydrogen peroxide treatment to enhance water solubility. Specifically, 35% hydrogen peroxide solution having a solid content of 1.5% by mass was added to the obtained solid content, and stirring and leaving every 15 minutes were repeated for 1 hour at room temperature. Was converted to hexavalent chromium. The liquid component was removed using 100 mesh, and the stirring and washing using the 4 times amount of water of the solid content and the liquid component removal were repeated twice.

  Collagen as a raw material for synthetic leather paste was prepared from collagen fibers obtained by removing chromium as described above. To the obtained solid content, succinic anhydride having a solid content of 0.1 to 0.15% by mass was mixed and allowed to stand at 5 to 10 ° C. for 12 to 16 hours. Next, 0.1-0.15 mass% sodium sulfite of the solid content was added and allowed to stand at room temperature for 1 hour. Finally, the pH was adjusted to 6.9 to 7.2 using β-aminoethanol. The obtained solid content was stored at 10 ° C. or lower.

  The solid content was taken, dispersed in water twice as much as the solid content, and collagen pulverization was repeated twice using a pulverizer Osterlizer Blender 890 (Oster). The length of the obtained pulverized collagen product was 300 μm in average length of the maximum width of 200 collagen fibers. In addition, the said average length put the collagen ground material in water dispersion | distribution on the slide glass CG-100 with a scale (made by Uchida Yoko Co., Ltd.), photographed with the optical microscope, and measured length using a caliper. Average value. The pulverized product was recovered, 5% by volume of isopropyl alcohol was recovered, and the mixture was allowed to stand for 1 hour to remove moisture. The solution was removed by suction filtration with 100 mesh to obtain a pulverized collagen product as a raw material for the synthetic leather paste.

(Manufacture of synthetic leather paste)
The obtained collagen pulverized product is mixed with an equal amount of water of the pulverized product, and urea is 1 to 1.2% by mass, sodium chloride is 0.35 to 0.4% by mass with respect to the collagen pulverized product, And 3-5% by mass of Catalix GS (manufactured by Clariant Co.), which is a weak cationic greasing agent for leather. The mixture was allowed to stand at 5 ° C. or lower for 24 hours. Next, the mixture was repeatedly stirred and allowed to stand at 5 to 20 ° C., and the generated moisture was removed to obtain a paste in which the moisture content of the mixture was adjusted to 80 to 85%. 100 parts by mass of the paste, 13 parts by mass of glycerin as a plasticizer, Takelac WS-6021 as an aqueous polyurethane resin composition (silanol group-containing aqueous polyurethane resin composition containing DBU; isophorone diisocyanate / polyester / solid content 30 %; Made by Mitsui Chemicals, Inc.) 37 parts by mass, Denacol Ex-830 as a water-based epoxy resin (polyglycidyl ether-based epoxy resin; epoxy equivalent: 268 WPE, viscosity: 70 mPa · s, bifunctional; manufactured by Nagase ChemteX Corporation) 37 parts by mass, and 2 parts by mass of Denacol Ex-614B (polyglycidyl ether-based epoxy resin; epoxy equivalent: 173 WPE, viscosity: 5000 mPa · s, water content: 94%, tetrafunctional or higher; manufactured by Nagase ChemteX Corporation), and As a pigment Of Disperse Black EX (KK Toupe) were mixed 1.5 parts by weight, were mixed with slow stirring up to 50 ° C., to produce a synthetic leather paste. The molar ratio of the carboxyl group of Takelac WS-6021 and the epoxy group of Denacol Ex-614B is carboxyl group: epoxy group = 1: 1.3, and the carboxyl group of Takelac WS-6021 and Denacol Ex- The molar ratio of 830 to the epoxy group is carboxyl group: epoxy group = 1: 2.5. Therefore, there will be more epoxy groups of Denacol Ex-830 which provide a softness | flexibility than a carboxyl group. Further, at least one epoxy group of Denacol Ex-830 is bonded to the carboxyl group of the polyurethane resin together with the epoxy group of Denacol Ex-614B.

(Manufacture of synthetic leather sheets)
To the obtained synthetic leather paste, 13 parts by mass of a lepton enhancer CP (manufactured by BASF), which is a preform type foaming agent, was added and heated to 65 ° C. while slowly stirring. Subsequently, it cooled until it became 45 degrees C or less, and also 4 mass parts of lepton enhancer CE (made by BASF) which is a thermal foaming type foaming agent was added. The obtained foam was molded. Finally, the foam was extruded and injected onto a sheet obtained by pulverizing the leather as a base material into a fiber and press-molding it.

[Example 2]
A synthetic leather sheet was produced in the same manner as in Example 1 except that water-based polyurethane resin composition Takelac WS-5000 was used as the polyurethane resin having at least one siloxane bond.

[Comparative Example 1]
Except for using UB-1770 (non-yellowing polyurethane resin emulsion; manufactured by Dainippon Ink Co., Ltd.), which is an aqueous polyurethane resin having no silanol group, instead of the polyurethane resin having at least one siloxane bond. A synthetic leather sheet was produced in the same manner as in Example 1.

[Comparative Example 2]
Example except that PRU-22 (aliphatic isocyanate polyurethane resin aqueous solution; manufactured by ALPA spa) which is an aqueous polyurethane resin having no silanol group was used instead of the polyurethane resin having at least one siloxane bond. A synthetic leather sheet was produced in the same manner as in No. 1.

[Comparative Example 3]
A synthetic leather sheet was produced in the same manner as in Example 1 except that LCC binder TF-80 (Dainippon Ink Co., Ltd.), which is an acrylic resin, was used instead of the polyurethane resin having at least one siloxane bond. However, the viscosity was high and could not be molded.

[Comparative Example 4]
A synthetic leather sheet is produced in the same manner as in Example 1 except that Aron NW-400 (manufactured by Toagosei Co., Ltd.), which is an acrylic resin, is used instead of the polyurethane resin having at least one siloxane bond. did.
(Evaluation results)
The obtained synthetic leather sheet was compared with natural leather.

  When a polyurethane resin having at least one siloxane bond is used as in the synthetic leather sheets of Examples 1 and 2, collagen fibers having a large size and forming a three-dimensionally entangled tissue can be contained. As a result, a synthetic leather having a natural leather-like texture was obtained. Moreover, the synthetic leather showed excellent moisture absorption / release properties like natural leather by containing collagen having a large size and forming a three-dimensionally entangled tissue. Furthermore, it can be understood that the epoxy resin contained in the synthetic leather sheet is provided with flexibility by being present alone or in an interaction state with collagen.

  In the synthetic leather sheets of Comparative Examples 1 and 2, since the collagen fibers were swollen and aggregated with water, the collagen fibers could not be sufficiently contained, and the texture and moisture absorption / release properties were inferior. On the other hand, there was a certain degree of flexibility due to the action of an epoxy resin present alone or in an interaction state with collagen.

  Even when the acrylic resin was used, the collagen fibers were swollen and aggregated with water, and the collagen fibers could not be sufficiently contained inside the polyurethane resin, and the texture and moisture absorption / release properties were inferior. On the other hand, there was a certain degree of flexibility due to the action of an epoxy resin present alone or in an interaction state with collagen.

  From the above results, the synthetic leather sheet produced from the synthetic leather paste according to the present invention has a natural leather-like texture and the like. Further, it can be understood that the epoxy resin added in a certain amount or more exhibits the property of imparting flexibility if the synthetic leather sheet contains collagen.

Claims (11)

  A synthetic leather paste comprising collagen, a polyurethane resin having at least one siloxane bond, and an aqueous solvent.   The synthetic leather paste according to claim 1, wherein the siloxane bond is formed by a dehydration condensation reaction using a strongly basic tertiary amine of a silanol group of the polyurethane resin as a catalyst.   The synthesis according to claim 1 or 2, wherein the polyurethane resin is formed by reacting a compound having active hydrogen, a compound having an isocyanate group, and a compound having active hydrogen and a hydrolyzable silicon group. Leather paste.   The synthetic leather paste according to any one of claims 1 to 3, wherein the collagen has a length of 100 to 1000 µm.   The synthetic leather paste according to any one of claims 1 to 4, wherein the collagen is derived from natural leather chrome shaving waste.   The synthetic leather paste according to any one of claims 1 to 5, further comprising an epoxy resin. Including collagen, a polyurethane resin having a carboxyl group, an epoxy resin, and an aqueous solvent,
A synthetic leather paste, wherein the epoxy resin has more epoxy groups than carboxyl groups, and at least one of the epoxy groups is bonded to the carboxyl groups.   The synthetic leather sheet formed using the synthetic leather paste of any one of Claims 1-7.   The repair agent containing the synthetic leather paste of any one of Claims 1-7. A step of pulverizing collagen to obtain a pulverized collagen product having a length of 100 to 1000 μm,
Mixing the aqueous polyurethane resin having at least one siloxane bond with the collagen pulverized product,
A method for producing a synthetic leather paste, comprising:   The manufacturing method of Claim 10 which further includes the process of dechromating the chrome leather shaving waste which arises during natural leather manufacture, and obtaining the said collagen.