JP2009228179A - Grained sheet-like material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grained environmentally responsive sheet-like material without using an organic solvent in a method for production, and having good peel strength between a substrate layer and a grain layer, and high-class surface grade. <P>SOLUTION: The grained sheet-like material is composed of the substrate layer comprising a self-emulsifiable type polyurethane in a nonwoven fabric composed of ultrafine fibers having ≥0.001 to ≤0.5 dtex average single fiber fineness, and the grain layer. The grained sheet-like material is characterized in that the self-emulsifiable type polyurethane contained in the nonwoven fabric is a polyurethane having a crosslinked structure by siloxane bonds in the molecular structure, and the grain layer is composed of the self-emulsifiable type polyurethane. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is an environmentally-friendly sheet-like material that does not use an organic solvent in the production method, has a good peel strength between the base layer and the silver surface layer, and has a high-grade surface quality. It is about things.

  Synthetic leather, called so-called silver, formed by coating or laminating a resin such as polyurethane on a fibrous base material has excellent characteristics not found in natural leather and is widely used for various applications. ing. Particularly in recent years, the use of furniture and automobile interior materials as well as clothing and miscellaneous goods has been increasing year by year. However, as the use expands, there has been a demand for high performance that was not conventionally required. For example, various kinds of environmental measures such as high quality closer to natural leather, more flexibility, higher durability, and the absence of organic solvent in the manufacturing process and the generation of volatile organic solvent (VOC) in the final product. There is a strong demand.

  In such a demand, for example, Patent Document 1 examines quality and flexibility close to those of natural leather. By defining the ratio of the ultrafine fiber layer constituting the base layer and the thickness direction of the woven / knitted layer, and inserting a polyurethane sheet between the ultrafine fiber layer and the woven / knitted layer, the texture is similar to that of natural leather. The surface wear resistance is improved by applying a silicone-modified polyurethane to the silver surface layer.

  Silicon-modified polyurethane is used for the silver surface layer to improve surface slip and exhibit wear resistance. Silicon slip surface is also excellent in terms of slipperiness between the base layer and the silver surface layer. In view of the durability as a leather-finished leather-like sheet, it is not practically usable and cannot be applied to, for example, an automobile seat application where a strong frictional force is applied.

  In addition, it is very important to improve the peel strength between the silver surface layer and the base layer as a durability to withstand practical use. Sheet-like materials are being studied.

  For example, Patent Document 2 has a structure having water-dispersible polyurethane inside a nonwoven fabric made of ultrafine fibers, and the presence of water-dispersible polyurethane inside the nonwoven fabric is concentrated on the sheet surface layer portion to resemble the silver surface of the nonwoven fabric surface layer. This is to form the appearance. Since no organic solvent is used in the manufacturing process, it is an environmentally friendly material, and since the silver layer and the base layer have an integrated structure, there is no peeling of the silver layer even in practical use. Is difficult to control, and high quality as natural leather is difficult to develop.

In other words, there is a demand for an environmentally-friendly material that does not use an organic solvent in the manufacturing method, a high-grade quality, and a silver-coated sheet with good peel strength between the base layer and the silver surface layer. A silver-tone sheet that satisfies these requirements has not yet been obtained.
JP 2007-162170 A JP 2007-46183 A

  In view of the background of such conventional technology, the present invention is an environmentally-friendly sheet-like material that does not use an organic solvent in the production method, has good peel strength between the base layer and the silver surface layer, and has a high-grade surface. The present invention provides a silver-like toned sheet having quality.

  That is, the silver-coated sheet-like product of the present invention is “from a base layer containing a self-emulsifying polyurethane in a nonwoven fabric composed of ultrafine fibers having an average single fiber fineness of 0.001 dtex or more and 0.5 dtex or less, and a silver surface layer. The self-emulsifying polyurethane contained in the nonwoven fabric is a polyurethane having a crosslinked structure with a siloxane bond in the molecular structure, and the silver surface layer is made of a self-emulsifying polyurethane. It is a characteristic silver-tone sheet.

  According to the present invention, an environmentally-friendly sheet-like material that does not use an organic solvent in the production method, has good peel strength between the base layer and the silver surface layer, and has a high-grade surface quality. A sheet-like material can be obtained.

  In the present invention, the silver-coated sheet is a sheet formed of a base layer including a nonwoven fabric composed of at least ultrafine fibers and a silver surface layer on the base layer, such as a silver surface of natural leather. It has an excellent surface appearance.

  First, the base layer will be described.

  The base layer contains a self-emulsifying polyurethane in a nonwoven fabric made of ultrafine fibers having an average single fiber fineness of 0.001 dtex or more and 0.5 dtex or less.

  Examples of the ultrafine fibers constituting the nonwoven fabric constituting the base layer include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyester such as polyethylene-2,6-naphthalenedicarboxylate, polyamide such as 6-nylon and 66-nylon. Various synthetic fibers such as acrylic, polyethylene, and polypropylene can be used. Of these, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate are preferably used from the viewpoints of strength, dimensional stability, and light resistance.

  The nonwoven fabric may be configured by mixing ultrafine fibers of different materials, and a woven fabric or a knitted fabric may be inserted into the nonwoven fabric for the purpose of improving the strength. In addition, the average single fiber fineness of the fiber which comprises a textile fabric or a knitted fabric does not have limitation in particular, The fiber of 0.001 dtex or more and 5 dtex or less may be sufficient.

  The average single fiber fineness of the ultrafine fibers constituting the nonwoven fabric is important to be 0.001 dtex or more and 0.5 dtex or less from the viewpoint of flexibility of the silver-coated sheet. Preferably it is 0.3 dtex or less, More preferably, it is 0.2 dtex or less. On the other hand, from the viewpoint of improving the peel strength between the base layer and the silver surface layer, if the fineness is too small, the fibers are easily cut and the peel strength is lowered, so that it is preferably 0.005 dtex or more.

  The average single fiber fineness of the ultrafine fibers constituting the non-woven fabric is determined by the scanning electron microscope (SEM) in the base layer portion of the cross section of the silver-tone sheet when the cross section of the ultrafine fibers is circular or an ellipse close to a circle. ) Photographed at a magnification of 2000 times, randomly selected 100 ultrafine fibers, measured fiber diameter, converted from the specific gravity of the material polymer to fineness, and further calculated the average value of the 100 fibers .

  On the other hand, when the ultrafine fiber constituting the nonwoven fabric has an irregular cross section, the outer peripheral circular diameter of the irregular cross section is calculated as the fiber diameter in the same manner. Furthermore, when a circular cross section and an irregular cross section are mixed, or when those having greatly different finenesses are mixed, 100 are selected and calculated so that each has the same number.

  Regarding the uniformity of the fineness of the ultrafine fibers constituting the nonwoven fabric, the fineness CV of the ultrafine fibers is preferably 10% or less. Here, the fineness CV is a percentage (%) value obtained by dividing the fineness standard deviation of the fibers constituting the fiber bundle by the average single fiber fineness in the bundle, and indicates that the smaller the value, the more uniform. Is. By setting the fineness CV to 10% or less, the flexibility of the base layer becomes uniform as a whole, and a partial difference in flexibility becomes difficult to occur. The fineness CV when the cross section of the ultrafine fiber is not a circle or an ellipse close to a circle is obtained by the same method as the calculation of the average single fiber fineness.

  The cross-sectional shape of the ultrafine fiber may be a round cross-section, but may be a polygonal shape such as an ellipse, a flat shape, or a triangle, or an irregular cross-section such as a sector shape or a cross shape.

  The nonwoven fabric constituting the base layer may be either a short fiber nonwoven fabric or a long fiber nonwoven fabric. However, when the texture is more important, the short fiber nonwoven fabric is preferable. Further, in the short fiber nonwoven fabric, the fiber length of the short fiber is preferably 25 mm or more and 90 mm or less in consideration of the physical strength of the nonwoven fabric due to the entanglement of the fibers.

  The base layer is formed by impregnating such a nonwoven fabric with a self-emulsifying polyurethane aqueous dispersion as an elastic resin binder so that the self-emulsifying polyurethane exists in the internal space of the nonwoven fabric. Due to the presence of self-emulsifying polyurethane in the inner space of the nonwoven fabric, the ultra-fine fibers constituting the nonwoven fabric are gripped to improve physical properties such as tensile strength and tear strength, and by providing moderate rebound, The hand-held feeling of a tone-like sheet can be expressed.

  The self-emulsifying polyurethane contained in the internal space of the nonwoven fabric is obtained from a self-emulsifying polyurethane aqueous dispersion. In the present invention, the nonwoven fabric is impregnated with the self-emulsifying polyurethane aqueous dispersion. Can exist in space. The self-emulsifying polyurethane water dispersion is a polyurethane water dispersion that is stably dispersed in water without using an emulsifier such as a surfactant, and is hydrophilic in the self-emulsifying polyurethane molecular structure. It has an internal emulsifier.

  The self-emulsifying polyurethane is usually handled in a state of being dispersed in water, and can be obtained from the manufacturer in this state. This is because once dried, it cannot be dispersed in water again.

  Internal emulsifiers are any of cationic systems such as quaternary amine salts, anionic systems such as sulfonates and carboxylates, nonionic systems such as polyethylene glycol, combinations of cationic systems and nonionic systems, and combinations of anionic systems and nonionic systems. However, the cationic internal emulsifier is inferior in light resistance such as yellowing, and the anionic internal emulsifier is preferably a nonionic internal emulsifier because it may cause a harmful effect due to the neutralizing agent.

  That is, when an anionic internal emulsifier is used, a neutralizing agent is required. For example, the neutralizing agent is a tertiary amine such as ammonia, triethylamine, triethanolamine, triisopropanolamine, trimethylamine, or dimethylethanolamine. In some cases, amines are generated and volatilized by the heat generated during film formation and drying, and released outside the system. Therefore, it is indispensable to introduce an apparatus for recovering volatile amines in order to suppress atmospheric emissions and work environment deterioration. In addition, if the amine does not volatilize by heating and remains in the final product sheet, it may be discharged to the environment when the product is incinerated. However, a nonionic internal emulsifier uses a neutralizing agent. Therefore, it is not necessary to introduce an amine recovery device, and there is no fear of remaining amine in the sheet. In addition, when the neutralizing agent is an alkali metal such as sodium hydroxide, potassium hydroxide or calcium hydroxide, or a hydroxide of an alkaline earth metal, the self-emulsifying polyurethane part exhibits alkalinity when wet. However, since the nonionic internal emulsifier does not use a neutralizing agent, there is no need to worry about degradation due to hydrolysis of the self-emulsifying polyurethane.

  As the self-emulsifying polyurethane used in the present invention, those having a structure obtained by appropriately reacting polyol, polyisocyanate, chain extender, and internal crosslinking agent in addition to the internal emulsifier can be used.

  As the polyol, a polycarbonate-based diol, a polyester-based diol, a polyether-based diol, a silicone-based diol, a fluorine-based diol, or a copolymer combining these may be used. Of these, polycarbonate diols and polyether diols are preferably used from the viewpoint of hydrolysis resistance, and polycarbonate diols are more preferable from the viewpoints of light resistance and heat resistance.

  The polycarbonate-based diol can be produced by an ester exchange reaction between an alkylene glycol and a carbonate ester, or a reaction between phosgene or chloroformate ester and an alkylene glycol. Examples of the alkylene glycol include linear chains such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and 1,10-decanediol. Alkylene glycol, branched alkylene glycol such as neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,4 -Alicyclic diols such as cyclohexanediol, aromatic diols such as bisphenol A, glycerin, trimethylolpropane, pentaerythritol and the like. Either a polycarbonate diol obtained from a single alkylene glycol or a copolymerized polycarbonate diol obtained from two or more types of alkylene glycols may be used.

  Examples of the polyisocyanate include aliphatic systems such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and xylylene diisocyanate, and aromatic systems such as diphenylmethane diisocyanate and tolylene diisocyanate, and these may be used in combination. Of these, aliphatic systems such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and isophorone diisocyanate are preferable from the viewpoint of light resistance.

  As the chain extender, amines such as ethylenediamine and methylenebisaniline, diols such as ethylene glycol, and polyamines obtained by reacting polyisocyanate with water can be used.

  The internal cross-linking agent is a compound having a functional group capable of cross-linking that is introduced into the molecular structure in advance when a self-emulsifying polyurethane is synthesized as a part of the self-emulsifying polyurethane molecule. , A compound used to introduce a silanol group into a self-emulsifying polyurethane molecular structure. By introducing a silanol group into the molecular structure of the self-emulsifying polyurethane, the self-emulsifying polyurethane existing in the inner space of the nonwoven fabric has a cross-linked structure by siloxane bonds. Durability can be dramatically improved. Moreover, it contributes to the peeling strength improvement of the silver surface layer and base layer which are mentioned later.

  A compound used for introducing a silanol group into a self-emulsifying polyurethane molecular structure is a compound containing an active hydrogen group capable of reacting with at least one isocyanate group and a hydrolyzable silicon group in one molecule. It is.

  The hydrolyzable silicon group means a group in which a hydrolyzable group that is hydrolyzed by moisture is bonded to a silicon atom. Specific examples of the hydrolyzable group include a hydrogen atom, a halogen atom, and an alkoxy group. And generally used groups such as an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group that has low hydrolyzability and is relatively easy to handle is preferable. The hydrolyzable group is bonded to one silicon atom in the range of 1 to 3, but from the viewpoint of reactivity of the hydrolyzable silyl group, water resistance, etc., those having 2 to 3 bonds are preferable. .

  Examples of the active hydrogen group capable of reacting with an isocyanate group include a mercapto group, a hydroxyl group, and an amino group.

  Hydrolyzable silicon group-containing compounds having a mercapto group as an active hydrogen group and an alkoxy group as a hydrolyzable group include, for example, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyl. Examples of the hydrolyzable silicon group-containing compound having an amino group as an active hydrogen group and an alkoxy group as a hydrolyzable group include dimethoxysilane and γ-mercaptopropylmethyldiethoxysilane. Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyldimethoxysilane, γ- (2-aminoethyl) aminopropyldiethoxysilane, γ-aminopropyltrimethoxysilane .gamma.-aminopropyltriethoxysilane, .gamma.-aminopropyl dimethoxysilane, .gamma.-aminopropyl diethoxy silane and the like. Among these, from the viewpoint of weather resistance and hydrolysis resistance, it is preferable to introduce a hydrolyzable silicon group into the middle part of the self-emulsifying polyurethane molecule, and further a hydrolyzable silicon group-containing compound having two or more active hydrogen groups Is preferred.

  The self-emulsifying polyurethane into which the hydrolyzable silicon group-containing compound has been introduced contains a crosslinked structure due to a siloxane bond in the state of being present in the interior space of the nonwoven fabric. With this cross-linked structure, the durability of the self-emulsifying polyurethane can be dramatically improved, and the deterioration of the physical properties due to the deterioration of the self-emulsifying polyurethane can be suppressed in the silver-coated sheet. Furthermore, when a crosslinked structure is formed between the resin forming the silver surface layer and the self-emulsifying polyurethane of the base layer in the silver surface layer described later, the peel strength between the silver surface layer and the base layer is greatly increased. Can be improved.

  Here, in order to form a siloxane bond, silanol groups directly bonded to the polymer need to be condensed. Therefore, the presence of a siloxane bond indicates that the silanol groups are condensed and a crosslinked structure that bonds the polymers.

  The presence or absence of a siloxane bond can be confirmed by a peak due to the siloxane bond in the measurement of polyurethane by NMR.

  The content of silicon atoms is preferably more than 0% by weight and 1% by weight or less based on the weight of polyurethane. As the number of cross-linked structures due to siloxane bonds increases, the durability of the self-emulsifying polyurethane, such as hydrolysis resistance, improves. However, if too much, the flexibility of the self-emulsifying polyurethane decreases and the flexibility of the silver-toned sheet-like material decreases. descend.

  In addition, content of a silicon atom can be quantified by performing the elemental analysis of the polyurethane-like toned sheet-like material or the polyurethane extracted from the silver-like toned sheet-like material.

  The self-emulsifying polyurethane present in the nonwoven fabric may be used alone or in combination of two or more, and other polymers may be used in combination.

  Examples of other polymers include water-dispersible and water-soluble polymers such as acrylic and silicone.

  The self-emulsifying polyurethane present in the internal space of the nonwoven fabric preferably does not substantially adhere to the ultrafine fibers constituting the nonwoven fabric.

  Since the ultrafine fibers and the self-emulsifying polyurethane are not substantially in close contact with each other, the self-emulsifying polyurethane does not hinder the movement of the ultrafine fibers, and thus the silver-tone sheet is very flexible.

  The term “substantially not adhered” as used herein means that the self-emulsifying polyurethane becomes an ultrafine fiber when a scanning electron microscope (SEM) photograph of the cross section of the base layer of the silver-coated sheet is observed at a magnification of 300 times. It means that it is not adhered and it can be confirmed that a void exists between the self-emulsifying polyurethane and the ultrafine fiber. There may be a partial contact, but basically there is a gap.

  Self-emulsifying polyurethanes are pigments such as carbon black, dyes, antifungal agents, light-proofing agents such as antioxidants and UV absorbers, flame retardants, penetrating agents and lubricants, anti-blocking agents such as silica and titanium oxide, antistatic A surfactant such as an agent, an antifoaming agent such as silicone, a filler such as cellulose, and a coagulation adjusting agent may be contained.

  The content of the self-emulsifying polyurethane relative to the weight of the base layer is preferably 20% by weight or more and 200% by weight or less. By making it 20% by weight or more, it is possible to obtain sheet strength and prevent the fibers from falling off, and by making it 200% by weight or less, it is possible to prevent the texture from becoming harder than necessary. More preferably, it is 30 wt% or more and 180 wt% or less.

  The base layer may contain functional agents such as dyes, pigments, softeners, texture modifiers, antibacterial agents, deodorants, water repellents, light proofing agents, weathering agents, and the like.

  Next, the silver layer will be described.

  The resin constituting the silver surface layer is a self-emulsifying polyurethane that is a water-dispersible polyurethane. When forced emulsification type polyurethane is used, it is not preferable because water resistance and abrasion resistance are lowered due to the surfactant remaining between the emulsions, and stickiness due to bleed out of the surfactant occurs.

  As the self-emulsifying polyurethane constituting the silver layer, the self-emulsifying polyurethane used in the base layer can be used. That is, those having a structure obtained by appropriately reacting the same polyol, polyisocyanate, chain extender, and internal emulsifier as described above can be used, and those described above can be used.

  Among these, polyols are preferably polycarbonate polyols from the viewpoint of durability such as light resistance and hydrolysis resistance, and abrasion resistance, and polyisocyanates are hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, etc. from the viewpoint of yellowing resistance. The aliphatic system is preferred.

  For the purpose of improving durability such as hydrolysis resistance and light resistance of the self-emulsifying polyurethane, and further improving peel strength between the silver surface layer and the substrate layer, a crosslinking agent can be used in combination. The cross-linking agent may be an internal cross-linking agent or an external cross-linking agent added as the third component. However, the cross-linking agent is an internal cross-linking agent that can cross-link the inside of the polyurethane more uniformly and the self-emulsifying polyurethane is relatively hard to cure. Preferably there is.

  As the external crosslinking agent, a resin having a reactive functional group such as a melamine resin, an epoxy resin, an isocyanate, a blocked isocyanate, a carbodiimide, an oxazoline group, or a silanol group can be used.

  The internal cross-linking agent is not particularly limited, but it is preferable to use a silanol group as in the base layer. Crosslinking by a siloxane bond formed by using a silanol group can improve durability such as hydrolysis resistance and light resistance while maintaining the flexibility of the self-emulsifying polyurethane constituting the silver surface layer. Furthermore, a crosslinked structure by a siloxane bond can be formed between the self-emulsifying polyurethane having a silanol group in the base layer and the self-emulsifying polyurethane having a silanol group constituting the silver surface layer. The peel strength between the face layer and the substrate layer is remarkably improved.

  The self-emulsifying polyurethane constituting the silver layer may be used alone or in combination of two or more, and other polymers may be used in combination.

  Examples of other polymers include water-dispersible and water-soluble polymers such as acrylic and silicone.

  The self-emulsifying polyurethane constituting the silver layer is composed of pigments such as carbon black, dyes, antifungal agents, light-proofing agents such as antioxidants and UV absorbers, flame retardants, penetrants and lubricants, silica and titanium oxide. May contain anti-blocking agents such as anti-blocking agents, surfactants such as antistatic agents, antifoaming agents such as silicone, fillers such as cellulose, coagulation regulators, antibacterial agents, deodorants, water repellents, etc. .

  Furthermore, the silver surface layer may have a topcoat layer on the outermost surface for the purpose of improving wear resistance and light resistance. As the top coat layer, polycarbonate-based polyurethane can be used.

  If the thickness of the silver surface layer is too thick, the flexibility of the silver-adjusted sheet-like material is impaired, and if it is too thin, the wear resistance is reduced. Therefore, the thickness is preferably 0.05 mm or more and 1.5 mm or less. Moreover, it is preferable that a topcoat layer is also 0.01 mm or more and 1 mm or less for the same reason.

  An adhesive layer may be present between the silver surface layer and the substrate layer.

  The adhesive layer is not particularly limited as long as it can be bonded, but for example, polyurethane, acrylic, natural rubber or the like can be used. From the viewpoint of reducing the amount of organic solvent contained in the silver-coated sheet, a water emulsion It is preferable to use a system, water-soluble, or solvent-free resin, and polyurethane is preferable from the viewpoint of flexibility.

  The adhesive layer may be applied in the form of dots, may be applied in the form of stripes, lattices, etc., or may be applied over the entire surface, but it improves the flexibility of the silver-tone sheet. In order to do so, it is preferable that it is provided in a dot shape.

  Next, an example of a method for producing a silver-tone sheet according to the present invention will be described.

The method for producing a base layer of a silver-coated sheet according to the present invention may be obtained through the steps (1) to (3).
(1) A step of creating a sheet using ultrafine fiber-generating fibers composed of a combination of two or more kinds of polymer substances having different solubility in an alkaline aqueous solution.
(2) A step of impregnating the sheet with a self-emulsifying polyurethane aqueous dispersion to give the self-emulsifying polyurethane.
(3) A step of treating the sheet provided with the self-emulsifying polyurethane with an alkaline aqueous solution to develop ultrafine fibers.

  By carrying out the steps in the order of (1), (2), and (3), a self-emulsifying polyurethane and an ultrafine fiber form a structure that is not substantially adhered, and a very flexible base layer can be obtained.

  As a means for obtaining ultrafine fibers constituting the nonwoven fabric, ultrafine fiber generating fibers are used. A nonwoven fabric in which ultrafine fibers are entangled can be obtained by performing ultrafine fiber after entanglement of ultrafine fiber generating fibers in advance.

  As ultrafine fiber generation type fibers, two or more types of thermoplastic polymer components having different solubility in an alkaline aqueous solution are used as sea components and island components, and the sea components are dissolved and removed using an alkaline aqueous solution to remove island components from ultrafine fibers. The sea-island type composite fiber and the two-component thermoplastic polymer component are arranged alternately in a radial or multi-layer cross section, and each component is peeled and divided to split into ultrafine fibers, etc. Can be adopted. Among them, the sea-island type composite fiber is preferable from the viewpoint of the flexibility of the base layer because it can provide an appropriate gap between the island components, that is, between the ultrafine fibers inside the fiber bundle, by removing the sea component.

  For the sea-island type composite fiber, a sea-island type composite base is used, and a polymer inter-array system in which the two components of the sea and the island are mutually arranged and spun, and the mixed spinning in which the two components of the sea and the island are mixed and spun. Although a system etc. can be used, the sea island type composite fiber by a polymer array system is more preferable at the point from which the ultrafine fiber of uniform fineness is obtained.

  Here, the difference in solubility in an alkaline aqueous solution means that the dissolution rate is different by 20 times or more, more preferably 40 times or more under the condition that the ultrafine fiber is developed. If it is less than 20 times, it is difficult to control the fineness of the thermoplastic polymer component having low solubility when developing the ultrafine fiber, which is not preferable.

  The dissolution rate in the alkaline aqueous solution can be calculated from the weight ratio obtained by treating the treatment time as 1 hour in accordance with the chemical resistance test (test solution: sodium hydroxide 10%) of JIS K6911 (1995).

  As a sea component of the sea-island type composite fiber having high solubility in an aqueous alkali solution, from the viewpoint of the dissolution rate in an aqueous alkali solution and spinning stability, polyethylene terephthalate, polybutylene terephthalate, etc., polyester 5-sodium sulfosulfophthalate, polyethylene glycol A copolymerized polyester obtained by copolymerizing 5 to 12 mol% of sodium dodecylbenzenesulfonate, bisphenol A compound, isophthalic acid, adipic acid, dodecadioic acid, cyclohexylcarboxylic acid, or the like, or polylactic acid can be used. In particular, from the viewpoint of heat resistance and solubility in a weak alkaline aqueous solution, it is preferable to use a polyethylene terephthalate copolymer or polylactic acid obtained by copolymerizing 5 to 12 mol% of sodium 5-sulfoisophthalate. These copolymers may be not only binary but also ternary or higher multi-component copolymers.

  The obtained ultrafine fiber-generating fiber is preferably crimped and cut into a predetermined length to obtain a nonwoven raw cotton. A usual method can be used for crimping and cutting. The obtained raw cotton is made into a web with a cross wrapper or the like, and then the fibers are entangled to make a nonwoven fabric.

  As a method for obtaining a nonwoven fabric by entanglement of fibers, usual methods such as needle punching and water jet punching can be used.

  The obtained nonwoven fabric may be subjected to shrinkage treatment by dry heat treatment, hot water treatment, or wet heat treatment in order to improve the fineness of the fibers.

  Further, the non-woven fabric may be obtained by half-cutting (dividing into two sheets) or dividing into several sheets in the thickness direction of the non-woven fabric before applying the self-emulsifying polyurethane water dispersion.

  In applying the self-emulsifying type polyurethane water dispersion to the nonwoven fabric, the nonwoven fabric is impregnated with the polyurethane water dispersion or applied to dry heat solidification, and the nonwoven fabric is impregnated with the polyurethane water dispersion and then wet heat solidified. There are a method of heat drying, a method of wet coagulation in hot water and heat drying, and a combination thereof, but there is no particular limitation.

  If the drying temperature is too low, the drying time will be long, and if it is too high, it may cause thermal degradation of the self-emulsifying polyurethane, so that it is preferably 80 ° C. or higher and 180 ° C. or lower. More preferably, it is 90 ° C or higher and 160 ° C or lower.

  The polyurethane water dispersion used for the production of the base layer is a polyurethane water dispersion dispersed in water as an emulsion, and is a self-emulsifying polyurethane water dispersion containing no emulsifier such as a surfactant.

  When a forced emulsification-type polyurethane aqueous dispersion containing an emulsifier such as a surfactant is used, the surface of the obtained base layer generates stickiness or the like due to the emulsifier. Increase and lead to cost increase. Furthermore, the forced emulsification type polyurethane water dispersion is not preferred because the presence of an emulsifier lowers the water resistance of the polyurethane film formed into a film, so that the polyurethane drops into the dyeing liquid during dyeing.

  The self-emulsifying polyurethane water dispersion may contain a water-soluble organic solvent in an amount of 0% by weight to 40% by weight with respect to the aqueous dispersion in order to improve storage stability and film forming property. It is preferable that the organic solvent is contained in an amount of 0 wt% to 1 wt% because of concerns such as the release of the organic solvent into the atmosphere due to heating and the residual organic solvent in the final product.

  The self-emulsifying polyurethane aqueous dispersion is a self-emulsifying polyurethane aqueous dispersion containing at least one silanol group in the self-emulsifying polyurethane molecular structure (hereinafter referred to as silanol group-containing self-emulsifying polyurethane). By containing a silanol group, silanol groups condense at the time of film formation, and the crosslinked structure by a siloxane bond is formed, and the alkali hydrolysis resistance of polyurethane improves dramatically.

  Silanol groups in the silanol group-containing self-emulsifying polyurethane are hydrolyzed in a compound containing at least one isocyanate group capable of reacting with at least one isocyanate group and a hydrolyzable silicon group in one molecule used in the reaction. It is produced by hydrolyzing a functional silicon group in water. Silanol groups in the silanol group-containing self-emulsifying polyurethane have sufficient water around them, so they do not reach the stage where silanol groups react with each other to form siloxane bonds, and exist stably in water.

  The silanol group contained in the silanol group-containing self-emulsifying polyurethane may be bonded to at least one or both of the both ends of the silanol group-containing self-emulsifying polyurethane molecule, or both. Since it affects the water resistance, physical properties, etc. of the self-emulsifying polyurethane after film formation, it is preferable to contain a silanol group in the middle part of the silanol group-containing self-emulsifying polyurethane molecule.

  The concentration of the self-emulsifying polyurethane aqueous dispersion (content of the self-emulsifying polyurethane relative to the self-emulsifying polyurethane aqueous dispersion) is 10% by weight or more and 50% by weight from the viewpoint of storage stability of the self-emulsifying polyurethane aqueous dispersion. The following is preferred.

  The self-emulsifying polyurethane aqueous dispersion preferably has a thermal gelation temperature. By having a thermal gelation temperature, it is possible to suppress the polyurethane migration phenomenon when the sheet is impregnated and dried. However, if the thermal gelation temperature is too low, there is a high possibility of gelation in the storage of the polyurethane water dispersion, and if it is too high, the migration phenomenon cannot be suppressed. preferable.

  The self-emulsifying polyurethane aqueous dispersion preferably has a heat-sensitive gelation property alone, but for the purpose of imparting the heat-sensitive gelation property to the self-emulsifying polyurethane water dispersion or lowering the heat-sensitive gelation temperature, Inorganic salts such as calcium, sodium sulfate and potassium sulfate may be added.

  In addition, when applying a self-emulsifying polyurethane aqueous dispersion, a pigment such as carbon black, a dye, an antifungal agent, a light-resistant agent such as an antioxidant or an ultraviolet absorber, a flame retardant, a penetrating agent or a lubricant. Antiblocking agents such as silica and titanium oxide, antistatic agents, antifoaming agents such as silicone, fillers such as cellulose, polyurethane coagulation adjusting agents, and the like can be added and used.

  In the base layer, a self-emulsifying polyurethane is applied to a sheet made of ultrafine fiber-generating fibers, and then the ultrafine fibers are expressed by treating with an alkaline aqueous solution.

  The alkaline aqueous solution is not particularly limited, and an aqueous solution such as sodium hydroxide or potassium hydroxide, an ammonia salt, or the like can be used.

  The concentration of the aqueous alkali solution is not particularly limited as long as ultrafine fibers can be expressed, but is preferably 0.05 mol / L or more and 10 mol / L or less.

  The treatment with an alkaline aqueous solution is to immerse a sheet made of ultrafine fiber-generating fibers after application of a self-emulsifying polyurethane and to perform a constriction liquid. In the case of a sea-island type composite fiber divided by physical force, the sea component dissolved in alkaline water is eluted to generate ultrafine fibers, so the method is not particularly limited, but for example, a liquid dyeing machine or A refining apparatus etc. and the process using those combination are mentioned.

  The temperature and time in the treatment using a liquid dyeing machine are preferably 50 ° C. or higher and 140 ° C. or lower and 5 minutes or longer and 90 minutes or shorter, respectively.

  In addition, for the purpose of improving the generation of ultrafine fibers, heat treatment, steam treatment, treatment with addition of a penetrant such as a surfactant may be performed as appropriate, and treatment with an acidic aqueous solution having a pH of 3 or less is performed in advance. After performing, you may process by alkaline aqueous solution.

  By combining the base layer and the silver surface layer obtained by the above-described production method or the like, it is possible to obtain the silver-coated sheet-like product of the present invention.

  The silver surface layer may be coated with a resin directly on the base layer, or may be laminated on the base layer via an adhesive layer after being coated on a release paper or the like, or may be heat-laminated.

  In the case of laminating, after forming the topcoat layer on the release paper, the resin layer and the adhesive layer may be formed in this order and combined with the base layer.

  The forming method of the silver surface layer is not particularly limited as long as it is a known forming method represented by a wet surface forming method, a dry surface forming method, a melt surface forming method and the like.

  Further, when a release paper is not used, a desired embossing can be performed by embossing.

  Further, raising treatment may be performed for the purpose of softening the appearance and texture of the back side.

  The silver-tone sheet according to the present invention may be dyed. Dyeing may be performed after dyeing only the base layer and then combined with the silver layer, or after combining the silver layer with the base layer. It is preferable to use a liquid dyeing machine because the dyeing method can be softened by giving a stagnation effect simultaneously with dyeing. As the liquid dyeing machine, a normal liquid dyeing machine can be used.

  If the dyeing temperature is too high, the self-emulsifying polyurethane of the base layer and the resin of the silver surface layer may be deteriorated. On the other hand, if the dyeing temperature is too low, the dyeing to the fiber becomes insufficient. Generally, it is preferably 80 ° C. or higher and 150 ° C. or lower, and more preferably 110 ° C. or higher and 130 ° C. or lower.

  The dye is not particularly limited and may be selected according to the ultrafine fiber constituting the nonwoven fabric. For example, a polyester-based ultrafine fiber is a disperse dye, and a polyamide-based ultrafine fiber is a dye such as an acid dye or a metal-containing dye, and those Can be used.

  When dyed with disperse dyes, reduction washing may be performed after dyeing.

  Moreover, it is preferable to use a dyeing assistant during dyeing for the purpose of improving the uniformity and reproducibility of dyeing. Further, a finishing agent treatment such as a softening agent such as silicone, an antistatic agent, a water repellent, a flame retardant, and a light resistance agent may be applied. The finishing treatment may be performed after dyeing or in the same bath as dyeing.

  The silver-toned sheet-like material of the present invention is an interior material, shirt having a very elegant appearance as a skin material for furniture, chairs, wall materials, seats, ceilings, interiors, etc. in vehicles such as automobiles, trains, and aircraft. As industrial materials such as jackets, casual shoes, sports shoes, men's shoes, women's shoes, uppers and trims for shoes, bags, belts, wallets, etc., clothing materials used for some of them, and polishing pads It can be used suitably.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Evaluation methods]
(1) Average single fiber fineness A scanning electron microscope (SEM) photograph of the base layer of a non-woven fabric or a silver-tone-like sheet was taken at a magnification of 2000 times, and 100 circular or nearly elliptical fibers were randomly selected. The fiber diameter was selected, the fiber diameter was converted to the fineness from the specific gravity of the fiber material polymer, and the average value of 100 was calculated.

(2) Fineness CV
The cross-section inside the base layer of the nonwoven fabric or silver-coated sheet is observed with a scanning electron microscope (SEM) at a magnification of 2000 times. From the photograph, the ultrafine fibers constituting one bundle of bundle fibers are observed. The fiber diameter was measured, converted from the fiber diameter to the fineness of each single fiber, and the value obtained by dividing the fineness standard deviation of the fibers constituting the fiber bundle by the average single fiber fineness in the bundle was expressed as a percentage (%). The same measurement was performed on the five bundle fibers, and the average value was defined as the fineness CV.

(3) Structure of the silver-tone-like sheet-like material The cross-section of the base layer of the silver-tone-like sheet-like material is observed with a scanning electron microscope (SEM) at a magnification of 300 times, and the adhesion state between polyurethane and ultrafine fibers is determined from the photograph. did.

(4) Confirmation of siloxane bond and silicon atom content Each of the polyurethane samples sampled from 3 or more random base layers of the sheet-like material or the silver surface layer is measured by NMR, and at least in any of the measurements, The presence or absence of a siloxane bond was confirmed by confirming the resulting peak. In addition, elemental analysis of polyurethane was performed at least 5 times, and the average value was taken as the silicon atom content.

(5) Thermosensitive gelation temperature of polyurethane water dispersion 10 g of polyurethane water dispersion with a solid content concentration of 10% by weight is put in a test tube, heated in a constant temperature hot water bath at 95 ° C., and the polyurethane water dispersion is fluid. The temperature at which gelation / solidification occurs after loss of heat was defined as the thermal gelation temperature. A total of two or more measurements were performed, and the average value was defined as the thermal gelation temperature.

(6) Peel strength of silver layer (N / cm)
It measured according to the measuring method prescribed | regulated to JISK6854-2: 1999. A polyurethane crepe rubber plate (length 150 mm, width 27 mm, thickness 5 mm) was used as the rigid adherend, and three pieces were cut out in the longitudinal and lateral directions as flexible adherends. A silver-tone sheet having a thickness of 250 mm and a width of 25 mm was used. A test piece was prepared by adhering a silver-coated sheet and a rubber plate using a polyurethane two-component adhesive so that the adhesive force was sufficiently exhibited. The stress required when the test piece was peeled off at a speed of 50 mm / min and the peel length were measured to obtain a stress-peel length curve. The average peel force was determined from the obtained curve. The average peel force obtained for each of the longitudinal direction and the transverse direction was calculated by averaging.

(7) Appearance quality The surface quality of the silver-tone-like sheet was evaluated by visual observation of the creases that occur when the silver-tone-like sheet was folded in the direction of the silver surface layer as follows. .
5: Shows creases that are as fine and fine as a leather with natural silver leather.
4: Although slightly inferior to leather with natural silver, it shows fine and fine creases.
3: Shows fine creases that are not precise.
2: Shows a large crease.
1: Shows large creases and large deep wrinkles with a buckling feeling.

(8) Flexibility (flexibility)
Based on method A (45 ° cantilever method) described in JIS L1096-8.19.1 (2005 version), five 2 × 15 cm test pieces were prepared and placed on a horizontal table having a 45 ° slope, and the test pieces The scale when the center point of one end of the test piece was in contact with the slope was read, and the average value of 5 sheets was obtained.

[Notation of chemical substances]
The meanings of the abbreviations of chemical substances used in each example and comparative example are as follows.
3MPC: poly (3-methylpentane carbonate) diol PTMG: polytetramethylene glycol PHC: polyhexamethylene carbonate diol H12MDI: dicyclohexylmethane diisocyanate HDI: hexamethylene diisocyanate HDA: hexamethylenediamine.

[Example 1]
Polyethylene terephthalate copolymerized with 8 mol% of sodium 5-sulfoisophthalate is 45 parts as sea component and 55 parts of polyethylene terephthalate as island component, and 36 islands are contained in one filament. A sea island-type fiber staple (fiber length: 51 mm) having a fineness of 2.8 dtex was used to form a web through a card and a cross wrapper, and a nonwoven fabric was formed by needle punching.

  This nonwoven fabric was treated in 90 ° C. hot water for 2 minutes to shrink and dried at 100 ° C. for 5 minutes. Next, the self-emulsifying type polyurethane water dispersion A having a solid content concentration of 25% by weight is impregnated and dried with hot air at a drying temperature of 120 ° C. for 10 minutes so that the weight of polyurethane with respect to the weight of island components of the nonwoven fabric is 30% by weight. A sheet provided with polyurethane was obtained.

  Next, this sheet was immersed in an aqueous solution of sodium hydroxide having a concentration of 10 g / L heated to 90 ° C. and treated for 30 minutes to obtain a sea-removed sheet from which sea components of sea-island fibers were removed. By observation with a scanning electron microscope (SEM) on the surface of the sea removal sheet, it was confirmed that the average single fiber fineness was 0.04 dtex and the fineness CV was 7.4%.

  And the sheet | seat (1) used as a base layer was obtained by smoothing the surface by grinding using 180 mesh endless sandpaper.

On the other hand, self-emulsifying type polyurethane water dispersion F (solid content concentration 30% by weight) thickened with a water-based thickener on release paper (AR-130SG: trade name manufactured by Asahi Roll Co., Ltd.) is applied in an amount of water dispersion. After applying and drying to an amount of 80 g / m ² , an adhesive layer was applied. With the adhesive layer being semi-dry and sticky, it was passed between metal rolls while being bonded to the ground surface of the sheet (1) serving as the substrate. And after performing the aging for 2 days in 40-50 degreeC atmosphere, the release paper was peeled.

It dye | stained with the disperse dye with the circular dyeing | staining machine, and obtained the toned sheet-like material of this invention.
The resulting silver-coated sheet was an environmentally friendly material that did not use an organic solvent in the production process, exhibited good appearance quality and texture, and had good peel strength.

[Example 2]
A sea island-type fiber staple having an average density of 3.8 dtex and a polyfilament containing 20 parts as a sea component and 80 parts of nylon 6 as an island component in one filament. Using a fiber length of 51 mm), a web was formed through a card and a cross wrapper, and a nonwoven fabric was formed by needle punching.

  This nonwoven fabric was treated in 90 ° C. hot water for 2 minutes to shrink and dried at 100 ° C. for 5 minutes. Next, impregnated with a self-emulsifying type polyurethane aqueous dispersion A having a solid content concentration of 25% by weight and dried with hot air at a drying temperature of 120 ° C. for 10 minutes to give polyurethane so that the weight of polyurethane relative to the weight of the nonwoven fabric becomes 20% by weight. Sheet was obtained.

  Next, this sheet was immersed in an aqueous solution of sodium hydroxide having a concentration of 40 g / L heated to 90 ° C. and treated for 30 minutes to obtain a sea removal sheet from which sea components of sea-island fibers were removed. By observation with a scanning electron microscope (SEM) on the surface of the sea removal sheet, it was confirmed that the average single fiber fineness was 0.2 dtex and the fineness CV was 7.5%.

  And the sheet | seat (2) used as a base layer was obtained by smoothing the surface by grinding using 180 mesh endless sandpaper.

On the other hand, a self-emulsifying type polyurethane water dispersion G (solid content concentration 30% by weight) thickened with an aqueous thickener on release paper (AR-130SG: trade name manufactured by Asahi Roll Co., Ltd.) is applied in an aqueous dispersion amount. After applying and drying to an amount of 80 g / m ² , an adhesive layer was applied. With the adhesive layer being semi-dry and sticky, it was passed between metal rolls while being bonded to the ground surface of the sheet (2) serving as the substrate. And after performing the aging for 2 days in 40-50 degreeC atmosphere, the release paper was peeled.

  It dye | stained with the disperse dye with the circular dyeing | staining machine, and obtained the toned sheet-like material of this invention.

  The resulting silver-coated sheet was an environmentally friendly material that did not use an organic solvent in the production process, exhibited good appearance quality and texture, and had good peel strength.

[Examples 3 and 4, Comparative Example 1]
Except having changed the polyurethane seed | species of the base layer and the polyurethane seed | species of a silver surface layer as Table 3, it carried out similarly to Example 1, and obtained the toned sheet-like material.

  The silver-coated sheets obtained in Examples 3 and 4 are environmentally friendly materials that do not use an organic solvent in the production process, exhibit good appearance quality and texture, and have good peel strength. The silver-coated sheet obtained in Comparative Example 1 is an environmentally-friendly material that does not use an organic solvent in the production process. By applying forced emulsification type polyurethane to the silver surface layer, a surfactant is obtained. Due to the above, the peel strength was low.

[Comparative Example 2]
A polyethylene terephthalate ultrafine fiber having a single fiber fineness of 0.1 dtex was produced by a direct spinning method, and short fibers cut to a fiber length of 5 mm were dispersed in water to obtain a suspension. This suspension was made into a paper sheet having a basis weight of 50 g / m ² . The papermaking sheet was laminated on both sides of a plain woven fabric having a weight per unit area of 50 g / m ^{2 made} of 84 dtex / 72 filament polyethylene terephthalate fiber, and three-dimensionally entangled and integrated by jetting a high-speed water stream with a water jet punch. The high-speed water flow was injected at a pressure of 3 MPa from a straight flow injection nozzle having a hole diameter of 0.1 mm.

  The laminated sheet was placed on an 80-mesh metal mesh having a suction device on the lower surface, and a high-pressure water stream was collided at a position 30 mm from the nozzle. This operation was performed from both the front and back sides of the laminated sheet to produce an ultrafine fiber nonwoven fabric having a fineness CV of 8.2%.

  This nonwoven fabric was treated in 90 ° C. hot water for 2 minutes to shrink and dried at 100 ° C. for 5 minutes. Next, impregnated with a forced emulsification type polyurethane aqueous dispersion E having a solid content concentration of 25% by weight, and hot-air drying at a drying temperature of 120 ° C. for 10 minutes to give polyurethane so that the weight of polyurethane relative to the weight of the nonwoven fabric becomes 20% by weight. Sheet was obtained. The fineness CV was confirmed to be 7.5% by observation with a scanning electron microscope (SEM) on the surface of the sea removal sheet.

  And the sheet | seat (6) used as a base layer was obtained by smoothing the surface by grinding using 180 mesh endless sandpaper.

On the other hand, forcible emulsification type polyurethane water dispersion I (solid content concentration 30% by weight) thickened with an aqueous thickener on release paper (AR-130SG: trade name manufactured by Asahi Roll Co., Ltd.) in an amount of aqueous dispersion. After applying and drying to an amount of 80 g / m ² , an adhesive layer was applied. With the adhesive layer being semi-dry and sticky, it was allowed to pass between the metal rolls while being bonded to the ground surface of the sheet (6) serving as the substrate. And after performing the aging for 2 days in 40-50 degreeC atmosphere, the release paper was peeled.

It dye | stained with the disperse dye with the circular dyeing machine, and obtained the silver-like tone-like sheet-like material.
The obtained silver-coated sheet is an environmentally friendly material that does not use an organic solvent in the manufacturing process, but the peel strength is low due to the influence of the surfactant contained in the forced emulsification type polyurethane, and the substrate layer The polyurethane was directly bonded to the fibers, so that the texture became hard and the appearance quality was poor.

Claims (4)

  A non-woven fabric made of ultra-fine fibers with an average single fiber fineness of 0.001 dtex or more and 0.5 dtex or less, a base layer containing a self-emulsifying polyurethane, and a silver-finished sheet-like material comprising a silver surface layer and contained in the nonwoven fabric A self-emulsifying polyurethane, wherein the self-emulsifying polyurethane is a polyurethane having a crosslinked structure with a siloxane bond in the molecular structure, and the silver surface layer is made of a self-emulsifying polyurethane.   2. The silver-coated sheet according to claim 1, wherein the self-emulsifying polyurethane constituting the silver surface layer is a polyurethane having a crosslinked structure by a siloxane bond in a molecular structure. 3. The silver-coated sheet according to claim 1, wherein at least a part of the self-emulsifying polyurethane and the ultrafine fiber contained in the base layer are not substantially in close contact with each other.   The self-emulsifying polyurethane contained in the base layer and at least one of the self-emulsifying polyurethane constituting the silver surface layer have a nonionic internal emulsifier. A silver-tone sheet.