JP5280303B2 - Nubuck-like sheet and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nubuck-toned sheet-like article having satisfactory appearance, touch feeling, handling and lighting effect as the nubuck-toned sheet-like article together with satisfactory abrasion resistance in a field where a high degree of endurance is required, and capable of being produced by a simple process, and a method for producing the same. <P>SOLUTION: In the nubuck-toned sheet-like article, a foamed layer consisting of a polyurethane resin formed by reacting a hot-melt urethane prepolymer with a urethane curing agent is stacked in a state of coexistence with pile fiber pieces on the surface of the side having the pile fiber pieces of a fibrous substrate having the pile fiber pieces consisting of a non-loop pile fiber on at least one face, at least a part of the pile fiber pieces protrude to be napped pile-like on the surface of the foamed layer and the surface of the protruded pile fiber pieces are covered with a protection film. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a sheet-like material having a nubuck-like appearance and a method for producing the same. More specifically, the present invention relates to a nubuck-like sheet-like material that is excellent in wear resistance and is particularly suitably used as an interior material and a vehicle interior material, and a method for manufacturing the same.

  Conventionally, a sheet-like material having an appearance imitating a nubuck of natural leather has been used for various applications such as clothing, bags, shoes, interior materials, and vehicle interior materials. As the nubuck-like sheet-like material, those produced by a method called a wet method have been widely put into practical use (for example, Patent Documents 1 and 2). In the wet method, a fiber base material is coated or impregnated with a polyurethane resin solvent (organic solvent) solution, which is immersed in a liquid containing a polyurethane resin non-solvent, and the solvent in the polyurethane resin solution becomes a non-solvent. By making it transfer, the polyurethane resin is solidified to form a porous layer, and then the surface is ground to give a nap-like appearance. The sheet-like material obtained by this wet method has a delicate nap-like appearance, a moist and slimy feel, a soft texture, rich in writing (handwriting) effect, and close to natural leather nubuck It is what. However, this method has a problem that a manufacturing process is complicated and a long time is required for manufacturing, and a manufacturing facility to be used is limited. In particular, it is necessary to consider the working environment and the global environment when removing non-solvents and solvents remaining in the polyurethane resin porous layer after immersion in a non-solvent solution of polyurethane resin. It was an inviting factor. In addition, it is difficult to obtain wear resistance that is fragile to external force and that is satisfactory as a field requiring high durability, for example, interior materials and vehicle interior materials.

  On the other hand, nubuck-like sheets manufactured by a method called a dry method have been widely put into practical use. In the dry method, a fibrous base material is coated or impregnated with a solvent solution or an aqueous dispersion of a polyurethane resin, dried, and then the surface is ground to give a raised appearance (for example, patent document) 3). In this method, the production process is simple and inexpensive, and the obtained sheet-like material also has a nap-like appearance at first glance and is excellent in wear resistance. However, it was rough and dry, had a hard texture, lacked lighting effects, and was far from natural leather nubuck.

  In addition, the nubuck-like sheet-like material is often provided with a concavo-convex pattern for the purpose of improving design properties, etc. In this case, an embossing process is separately required in the wet method or the dry method (usually before the grinding process). There is also a problem that the manufacturing cost increases due to an increase in the number of processes.

  There are two main methods for producing nubuck-like sheets, but as one form of dry method, a skin layer made of polyurethane resin prepared on release paper is bonded to a fibrous base material with an adhesive. After that, a release paper is peeled off and the surface of the skin layer is ground to give a nap-like appearance (for example, Patent Document 4). In this method, even when a concavo-convex pattern is imparted, it is sufficient to use a release paper having a concavo-convex pattern, and the manufacturing process is simple and low-cost, and a sheet-like material excellent in wear resistance can be obtained. . However, due to the presence of the adhesive layer, fiber pieces do not appear on the surface, and the skin layer made of polyurethane resin is only ground. Therefore, the appearance was rough, the texture was rough and dry, the texture was hard, the lighting effect was lacking, and it was completely different from the natural leather nubuck.

  Thus, the present situation is that no nubuck-like sheet-like material that is excellent in both nubuck-like sensory characteristics and wear resistance and that has a simple manufacturing process has not been obtained.

Japanese Patent Laid-Open No. 7-42082 Japanese Patent Laid-Open No. 7-42083 Japanese Patent Laid-Open No. 7-60885 Japanese Patent No. 30623399

  The present invention has been made in view of such a current situation, and is satisfactory in the field where high durability and sensory characteristics such as appearance, feel, texture, and lighting effect that can be satisfied as a nubuck-like sheet material are required. It is an object of the present invention to provide a nubuck-like sheet-like material that has both wear resistance and can be manufactured by a simple process, and a method for manufacturing the same.

In the first aspect of the present invention, a hot-melt urethane prepolymer and a urethane-cured material are provided on a surface of a fibrous base material having pile fiber pieces made of non-ring-like pile fibers on at least one surface. The foam layer made of polyurethane resin formed by reaction with the agent is laminated in a state of being mixed with the pile fiber pieces, and at least a part of the pile fiber pieces protrudes in a napped shape on the surface of the foam layer. The pile fiber piece is a nubuck-like sheet in which the surface is covered with a protective film.
The length of the pile fiber piece that protrudes in the form of napping on the surface of the foamed layer is preferably 10 to 300 μm, and the density is preferably 25,000 to 3.5 million pieces / (25.4 mm) ² .

The present invention secondly,
A step of preparing a prepolymer composition by mixing a hot melt urethane prepolymer in a heat-melted state and a urethane curing agent,
The pile fiber of a fibrous base material, which is obtained by applying a prepolymer composition to (a) a releasable base material and having pile fiber pieces made of non-round pile fibers on at least one side of the coated surface. The surface on the side having the piece is bonded together, or (b) the surface on the side having the pile fiber piece of the fibrous base material having the pile fiber piece made of non-round pile fiber on at least one surface. Applying, and bonding the releasable substrate to the coated surface;
A step of aging treatment to form a foam layer made of polyurethane resin,
A step of peeling the releasable substrate,
A step of grinding the surface of the foam layer to project at least a part of the tip of the pile fiber piece into the surface of the foam layer in a raised shape,
Applying a resin composition to the surface of the protruding pile fiber pieces;
A step of heat-treating to form a protective film covering the surface of the protruding pile fiber pieces;
Is a method for producing a nubuck-like sheet material.

  According to the present invention, a nubuck-like sheet-like material that is excellent in various properties such as appearance, feel, texture, lighting effect, and wear resistance and can be applied as an interior material or a vehicle interior material is manufactured in a simple process. Can do.

It is a cross-sectional schematic diagram in the manufacturing stage of the nubuck-like sheet material according to the embodiment, (A) is the stage of the fibrous base material, (B) is the stage before the grinding treatment of the foam layer, and (C) is the foam layer. (D) shows a product state after the grinding process.

  The nubuck-like sheet-like material of the present invention is formed on the surface of the fibrous base material having pile fiber pieces on at least one surface by the reaction of a hot melt urethane prepolymer and a urethane curing agent. The foam layer made of polyurethane resin is laminated so as to be mixed with the pile fiber pieces, and at least a part of the pile fiber pieces protrudes in a napped shape on the surface of the foam layer, and the surface of the protruding pile fiber pieces Is covered with a protective film.

  The fibrous base material used in the present invention is required to have pile fiber pieces on at least one surface. Here, the pile fiber piece is made of non-wound-like pile fiber, and refers to each single fiber forming napped on the surface of the fibrous base material, and made of pile yarn, for example, fiber bundle. They are distinguished from multifilament yarns and spun yarns. As long as the above requirements are satisfied, the form of the fibrous base material is not particularly limited, such as a knitted fabric, a woven fabric, and a non-woven fabric. In addition, a conventionally known solvent-based or solvent-free (including water-based) polymer compound, preferably a polyurethane resin or a copolymer thereof, or a mixture containing polyurethane resin as a main component is applied or impregnated, and dry coagulation is performed. Alternatively, a wet-coagulated product can be used. In addition, the material of the fibers constituting the fibrous base material is not particularly limited, and examples thereof include conventionally known fibers such as natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers. It may be combined. Of these, synthetic fibers are preferable, polyester fibers are more preferable, and polyethylene terephthalate is particularly preferable from the viewpoints of heat resistance and light resistance.

  The pile fiber piece possessed by at least one surface of the fibrous base material may be formed by knitting or weaving, or may be formed by raising treatment. Examples of those formed by knitting or weaving include double raschel knitted fabrics and moquette pile yarns that have been center-cut. Examples of the woven or knitted fabric knitted or woven with raised yarns in a long-tissued tissue portion and those with raised nonwoven fabrics can be given. Among these, a pile fiber piece formed by a raising process is preferable because a fiber fluff is easily expressed and a pile fiber piece excellent in appearance and lighting effect is obtained.

  As a method of raising a fibrous base material, an endless needle cloth or sandpaper rotating at high speed (a raising machine having a needle cloth as a raising means is a needle raising machine, a raising machine having a sand paper is an emery raising machine ( In general, a method in which a fibrous base material is contacted while being moved in a longitudinal direction is referred to as a buffing machine, a buffing machine, or an emery buffing machine). In the case of needle cloth raising treatment, select various conditions such as the density, length, angle, tip shape of the needle cloth, the number of rotations of the needle cloth during raising, the contact pressure with the fibrous base material, and the number of contacts. Thus, the surface state can be set as appropriate. Also in the emery raising process, the surface state can be appropriately set by selecting various conditions such as the particle size of the sand paper and the number of contact between the sand paper and the fibrous base material during raising. Furthermore, you may give the shirring process for adjusting a hair foot after raising, as needed.

  The length of the pile fiber piece (P, see FIG. 1 (A)) is preferably 0.1 to 2 mm, and more preferably 0.5 to 1.5 mm. If the length is less than 0.1 mm, the pile fiber pieces that are long enough to produce a lighting effect cannot be protruded on the surface of the foamed layer by grinding, and the resulting nubuck-like sheet is obtained. There is a possibility that the appearance and feel of the object may be impaired, or a sufficient lighting effect may not be obtained. When the length exceeds 2 mm, in the obtained nubuck-like sheet-like product, the adhesion between the pile fiber pieces and the foamed layer is deteriorated, the foamed layer is cracked, and the appearance and feel may be impaired.

  As for the numerical range defined in the present specification, those having a distribution such as the length of the pile fiber piece and the thickness of the foamed layer may have an average value within the range unless otherwise specified. .

  The fineness of the pile fiber pieces (single fiber fineness of the yarn forming the pile fiber pieces) is preferably 0.01 to 3 dtex (decitex), and more preferably 0.05 to 2 dtex. When the fineness is less than 0.01 dtex, the fiber fluff hardly appears, the appearance of the resulting nubuck-like sheet is impaired, the sufficient lighting effect cannot be obtained, and the wear resistance is deteriorated. There is a risk that. When the fineness exceeds 3 dtex, the feel of the nubuck-like sheet-like material obtained may be impaired or the texture may become hard.

The density of the pile fiber pieces is preferably from 50,000 to 3,500,000 present ^{/(25.4mm) 2,} and more preferably from 100,000 to 2,700,000 present ^{/(25.4mm) 2.} When the density is less than 50,000 pieces / (25.4 mm) ² , the adhesion between the pile fiber pieces and the foamed layer is deteriorated in the resulting nubuck-like sheet-like material, and the foamed layer is cracked, resulting in appearance and feel. May be damaged. When the density exceeds 3.5 million pieces / (25.4 mm) ² , it becomes difficult for the prepolymer composition that forms the foam layer to penetrate into the pile fiber pieces, and the thickness of the foam layer that is not mixed with the pile fiber pieces increases. As a result, the pile fiber pieces that are long enough to express the lighting effect cannot be raised on the surface of the foamed layer by the grinding process, and the appearance and feel of the resulting nubuck-like sheet are impaired. There is a risk that the texture may become stiff, or a sufficient writing effect may not be obtained.

  The total fineness of the yarns forming the pile fiber pieces is preferably 10 to 200 dtex, and more preferably 20 to 150 dtex. If the total fineness is less than 10 dtex, the fiber fluff hardly appears, the appearance of the resulting nubuck-like sheet is impaired, the sufficient lighting effect cannot be obtained, and the wear resistance is deteriorated. There is a risk. If the total fineness exceeds 200 dtex, the feel of the nubuck-like sheet-like material obtained may be impaired or the texture may become hard.

  The thickness of the fibrous base material including the pile fiber pieces is preferably 0.5 to 2.5 mm, and more preferably 0.8 to 2 mm. If the thickness is less than 0.5 mm, the texture of the resulting nubuck-like sheet may be paper-like, or a sufficient volume may not be obtained. If the thickness exceeds 2.5 mm, the texture of the nubuck-like sheet obtained may be hard.

  The nubuck-like sheet-like product of the present invention has a hot-melt urethane prepolymer and urethane cured as a first resin layer on the side having pile fiber pieces (hereinafter referred to as pile fiber one side) in the above fibrous base material. A foamed layer made of a polyurethane resin formed by reaction with an agent is laminated in a state where it is mixed with pile fiber pieces.

  As is well known, the polyurethane resin is a general term for polymer compounds having a urethane bond (—NHCOO—), and is generally produced by reacting a polyol and a polyisocyanate (crosslinking / curing reaction). The one-part type, which is provided in a polymerized state (that is, as a polyurethane resin), in which the reaction between the polyol and the polyisocyanate is almost completed, whereas the two-part curable type reacts the polyol and the polyisocyanate at the time of use. In general, it consists of two liquids, a urethane prepolymer (main agent) in which the reaction between the polyol and the polyisocyanate is stopped at an appropriate place, and a urethane curing agent. The polyurethane resin constituting the foam layer is classified into this two-component curable polyurethane resin. In addition, the hot melt property of urethane prepolymers is a property resulting from the molecular structure and is solid at room temperature or viscous to the extent that it is difficult to apply to a substrate, but when heated, it melts into a liquid state. That is, the property that the cohesive force is developed again by cooling.

  Since the hot melt urethane prepolymer used for forming the foamed layer is hot meltable, a prepolymer composition (a mixture of a hot melt urethane prepolymer and a urethane curing agent) is applied to a substrate in a heated and melted state. This eliminates the need to use organic solvents that adversely affect the human body and the global environment. For this reason, the process of removing the organic solvent in the manufacturing process becomes unnecessary, and the manufacturing cost can be reduced. In addition, since the prepolymer composition can be adjusted to a relatively high viscosity, excessive penetration into the fibrous base material can be suppressed, and because the prepolymer composition has a high solid content, pile fibers can be used. Appropriate physical voids are formed between the piece and the polyurethane resin obtained by curing. For this reason, the texture of the nubuck-like sheet-like material obtained does not become hard. Furthermore, since it is a two-component curable type that reacts with a urethane curing agent to form a polyurethane resin, it foams and the rubber elasticity peculiar to the resin is eased, so that it can have a soft texture. For this reason, the front-end | tip of a pile fiber piece can be made to protrude in the nap-like shape on the surface of a foaming layer easily by a grinding process. In addition, workability is good because a viscosity suitable for processing can be obtained at a temperature lower than that of the one-pack type. Nevertheless, the softening temperature after curing is high and the foamed layer has excellent heat resistance.

  Hereinafter, the hot melt urethane prepolymer, the urethane curing agent, and the polyurethane resin obtained by curing will be described. However, these characteristics, particularly the characteristics of the polyurethane resin, are reflected in the characteristics of the obtained nubuck-like sheet-like material. Needless to say.

In the present invention, the foam layer uses a prepolymer composition prepared by appropriately mixing a hot melt urethane prepolymer in a heat-melted state and a urethane curing agent,
(A) The prepolymer composition is applied to a releasable substrate, and the pile fiber single side of the fibrous substrate is bonded to the coated surface, or
(B) The prepolymer composition is applied to one side of a pile fiber of the fibrous base material, and a releasable base material is bonded to the coated surface,
Subsequently, it can form in the pile fiber single side | surface of a fiber base material by carrying out an aging process.

  As described above, the hot melt urethane prepolymer is obtained by a reaction between a polyol and a polyisocyanate, and depending on the ratio of the polyol and the polyisocyanate during production, a hot melt urethane prepolymer having a hydroxyl group at the molecular terminal There are two types of hot melt urethane polyisocyanate prepolymers having an isocyanate group at the molecular end. The corresponding urethane curing agents are polyisocyanates and polyols.

The curing reaction between the hot melt urethane prepolymer and the urethane curing agent is shown in the following formula (I). After all, this reaction is shown as a reaction between the hydroxyl group of the polyol and the isocyanate group of the polyisocyanate. In addition to the reaction with the hydroxyl group, the isocyanate group reacts with moisture in the atmosphere to produce an amine compound and carbon dioxide (formula (II) below), and further reacts in a chain with the reaction product ( Formulas (III) and (IV) below).
A large number of holes are formed in the resin layer by the carbon dioxide gas generated in the formula (II), and a foam layer is formed.

  The polyol that can be used in producing the hot-melt urethane prepolymer is not particularly limited, and examples thereof include polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol, polyolefin polyol, castor oil polyol, and silicone-modified polyol. These can be used alone or in combination of two or more. Of these, polyether polyol or polycarbonate polyol is preferred from the viewpoint of hydrolysis resistance. Further, polycarbonate polyol is more preferable from the viewpoint of light resistance and heat resistance, and polyether polyol is more preferable from the viewpoint of texture.

  On the other hand, the polyisocyanate that can be used for producing the hot melt urethane prepolymer is not particularly limited, and examples thereof include phenylene diisocyanate, tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), 2 , 4'-diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate and other aromatic diisocyanates, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), aliphatic such as dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate Diisocyanate or alicyclic diisocyanate, and 4,4'-diphenylmethane diisocyanate , And the like polymeric MDI containing dimers and trimers of isocyanate (MDI). Among these, 4,4′-diphenylmethane diisocyanate (MDI) is preferable in that the curing reaction can be easily controlled.

  The hot melt urethane polyol prepolymer used in the present invention can be obtained by reacting the above polyol and polyisocyanate under conditions where the hydroxyl group of the polyol is excessive with respect to the isocyanate group of the polyisocyanate. Under the present circumstances, it is preferable that it is 1.1-2.5, and, as for the equivalent ratio of a hydroxyl group / isocyanate group, it is more preferable that it is 1.2-2. When the equivalence ratio is less than 1.1, it is difficult to make both ends of the prepolymer into hydroxyl groups, and the isocyanate group remaining in the prepolymer reacts with surrounding moisture, resulting in an increase in molecular weight and an increase in viscosity. There is a possibility that workability may be deteriorated. When the equivalent ratio exceeds 2.5, when the prepolymer and the urethane curing agent are reacted, an unreacted hydroxyl group remains, and the polyurethane resin obtained by curing is prone to hydrolysis, and the physical properties related to strength are all general. There is a risk of getting worse.

  On the other hand, the hot melt urethane polyisocyanate prepolymer used in the present invention is obtained by reacting the above polyol and polyisocyanate under the condition that the isocyanate group of the polyisocyanate is excessive with respect to the hydroxyl group of the polyol. Can do. At this time, the equivalent ratio of isocyanate group / hydroxyl group is preferably 1.1 to 5, and more preferably 1.5 to 3. When the equivalence ratio is less than 1.1, unreacted hydroxyl groups remain in the prepolymer, and the polyurethane resin obtained by curing is likely to be hydrolyzed, which may deteriorate the overall physical properties related to strength. When the equivalence ratio exceeds 5, the stability is poor and the curing reaction may not be controlled.

  In order to produce the hot melt urethane prepolymer used in the present invention, various conventionally known methods can be adopted and are not particularly limited. For example, dripping a polyol from which water has been removed into a polyisocyanate, or mixing a polyisocyanate into a polyol from which water has been removed, and then heating and reacting in a batch system, or heating each polyol and polyisocyanate from which water has been removed. In addition, a method in which the reaction is carried out in a continuous extrusion reaction system after being introduced into the extruder at a predetermined ratio can be employed.

  The softening temperature of the hot melt urethane prepolymer thus obtained is preferably 20 to 100 ° C, and more preferably 40 to 70 ° C. When the softening temperature is less than 20 ° C., the softening temperature of the polyurethane resin obtained by curing is low, and sufficient heat resistance may not be obtained or the strength may be insufficient. When the softening temperature exceeds 100 ° C., a high temperature is required to obtain a viscosity suitable for processing, and workability may be deteriorated. In the present specification, the softening temperature is measured by differential scanning calorimetry using a DSC thermal analyzer.

Next, the urethane curing agent used in the present invention will be described.
When a hot melt urethane polyol prepolymer is used as a hot melt urethane prepolymer, a polyisocyanate is used as a urethane curing agent. When a hot melt urethane polyisocyanate prepolymer is used as a hot melt urethane prepolymer, a urethane curing agent is used. A polyol is used.

  The urethane curing agent that can be used for the hot melt urethane polyol prepolymer, that is, the polyisocyanate is not particularly limited, and examples thereof include tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), and modified diphenylmethane. Diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), xylene diisocyanate, tetramethylxylene diisocyanate, norbornene diisocyanate, triphenylmethane triisocyanate, polyphenylpolymethylene polyisocyanate, carbodiimide Containing polyisocyanate DOO, polyisocyanates containing allophanate groups, and the like can be illustrated polyisocyanates containing isocyanurate groups may be used in combination thereof singly or two or more. Among them, 4,4′-diphenylmethane diisocyanate (MDI) is preferable in terms of easy control of the curing reaction, and aliphatic polyisocyanate is preferable in terms of less yellowing of the polyurethane resin obtained by curing. Hexamethylene diisocyanate is more preferred.

  Furthermore, as a urethane curing agent, in addition to the above-mentioned polyisocyanate, a compound obtained by reacting a polyol and a polyisocyanate under a condition where an isocyanate group of the polyisocyanate is excessive with respect to a hydroxyl group of the polyol is used. Can do. This compound can be a main component in forming a polyurethane resin as a urethane polyisocyanate prepolymer, and those having hot melt properties can also be used as the hot melt urethane polyisocyanate prepolymer in the present invention. By using such a urethane polyisocyanate prepolymer as a urethane curing agent, in addition to working as a urethane curing agent, an effect as a chain extender can be obtained, so that the flexibility of a polyurethane resin obtained by curing is improved. Can do.

  On the other hand, the urethane curing agent that can be used for the hot melt urethane polyisocyanate prepolymer, that is, the polyol is not particularly limited. For example, polyester polyol, polyether polyol, polycarbonate polyol, acrylic polyol, polyolefin polyol, castor oil polyol And silicone-modified polyols, and the like. These can be used alone or in combination of two or more. Of these, polyether polyol or polycarbonate polyol is preferred from the viewpoint of hydrolysis resistance. Further, polycarbonate polyol is more preferable from the viewpoint of light resistance and heat resistance, and polyether polyol is more preferable from the viewpoint of texture.

  Further, as the urethane curing agent, in addition to the above-mentioned polyol, a compound obtained by reacting a polyol and a polyisocyanate under a condition in which the hydroxyl group of the polyol is excessive with respect to the isocyanate group of the polyisocyanate is used. it can. This compound can be a main component in forming a polyurethane resin as a urethane polyol prepolymer, and those having hot melt properties can also be used as the hot melt urethane polyol prepolymer in the present invention. By using such a urethane polyol prepolymer as a urethane curing agent, the same effect as when a urethane polyisocyanate prepolymer is used as a urethane curing agent for the hot melt urethane polyol prepolymer can be obtained.

Next, the equivalent ratio when the hot melt urethane prepolymer and the urethane curing agent are reacted will be described.
When the hot melt urethane polyol prepolymer is used as the hot melt urethane prepolymer and the polyisocyanate is used as the urethane curing agent, the equivalent ratio of isocyanate group / hydroxyl group is preferably 0.95 to 2, and 1.1 to 1 .3 is more preferable. When the equivalence ratio is less than 0.95, an unreacted prepolymer remains, and the polyurethane resin obtained by curing is likely to be hydrolyzed, so that the physical properties related to the strength may be deteriorated. If the equivalent ratio exceeds 2, the curing reaction may proceed too much and the texture may become hard. At this time, the amount of the urethane curing agent used with respect to 100 parts by weight of the prepolymer is usually 3 to 50 parts by weight, more preferably 5 to 40 parts by weight, although it depends on the molecular weight of the prepolymer and the urethane curing agent.

  On the other hand, when the hot melt urethane polyisocyanate prepolymer is used as the hot melt urethane prepolymer and the polyol is used as the urethane curing agent, the equivalent ratio of isocyanate group / hydroxyl group is preferably 1.1 to 10, 1.2 More preferably, it is ~ 3. If the equivalent ratio is less than 1.1, unreacted urethane curing agent remains, and the polyurethane resin obtained by curing is likely to be hydrolyzed, which may deteriorate the overall physical properties related to strength. If the equivalent ratio exceeds 10, the curing reaction may proceed too much and the texture may become hard. At this time, the amount of the urethane curing agent used with respect to 100 parts by weight of the prepolymer is usually 3 to 50 parts by weight, more preferably 10 to 30 parts by weight, although it depends on the molecular weight of the prepolymer and the urethane curing agent.

  In the prepolymer composition, if necessary, within a range that does not impair the physical properties of the polyurethane resin obtained by curing, a urethanization catalyst, a silane coupling agent, a filler, a thixotropic agent, a tackifier, a wax, Heat stabilizer, light resistance stabilizer, fluorescent whitening agent, foaming agent, thermoplastic resin, thermosetting resin, dye, pigment, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, oil repellent, Hollow foam, crystal water-containing compound, flame retardant, water-absorbing agent, moisture-absorbing agent, deodorant, foam stabilizer, antifoaming agent, antifungal agent, preservative, algaeproofing agent, pigment dispersant, inert gas, blocking Arbitrary components, such as an inhibitor and a hydrolysis inhibitor, can be used singly or in combination of two or more. Among them, it is preferable to use a urethanization catalyst in order to reduce the process load and improve the physical properties of the polyurethane resin.

  A mixing head is used to mix the hot melt urethane prepolymer and urethane curing agent, and optional components used as necessary. The mixing head is connected to a raw material tank for storing the prepolymer and the like through a supply pipe. After mixing and stirring at a ratio, the mixture is supplied to a coating apparatus.

  Hot melt urethane prepolymer is solid at room temperature or viscous to a degree that is difficult to apply to a substrate. To mix with other raw materials and apply to a substrate as a prepolymer composition, the prepolymer is heated and melted. And it needs to be liquid. The heating and melting temperature at this time is set to a temperature that is preferably 10 to 80 ° C., more preferably 20 to 60 ° C. higher than the softening temperature of the prepolymer. When the heating and melting temperature is higher than the softening temperature of the prepolymer by less than 10 ° C., the viscosity of the prepolymer is high, and workability at the time of application may be deteriorated. If the heating and melting temperature is higher than the softening temperature of the prepolymer by more than 80 ° C., the curing reaction may not be controlled. The heating and melting temperature is usually set in the range of 30 to 150 ° C, more preferably 40 to 120 ° C. By setting the heating and melting temperature in the above range, the temperature of the prepolymer composition is usually 30 to 150 ° C., more preferably 40 to 120 ° C., preferably 1000 to 15000 cps, more preferably 3000 to 10000 cps. It becomes a prepolymer composition having a viscosity (described later). Note that the prepolymer is melted by heating in a temperature-adjustable raw material tank.

  On the other hand, the urethane curing agent is solid or liquid at room temperature. In the case where the urethane curing agent is solid or liquid, it is preferable to adjust to an appropriate viscosity by heating in order to improve the handleability and uniformly mix with the prepolymer. Many urethane curing agents are liquid at room temperature, and the heating temperature is often lower than the heating and melting temperature of the prepolymer.

  The viscosity of the prepolymer composition is preferably 1000 to 15000 cps, more preferably 3000 to 10,000 cps. If the viscosity is less than 1000 cps, the prepolymer composition may excessively penetrate into the fibrous base material, and the resulting nubuck-like sheet-like material may become hard. When the viscosity exceeds 15000 cps, it becomes difficult for the prepolymer composition to penetrate into the pile fiber pieces of the fibrous base material, and as a result of increasing the thickness of the foamed layer that is not mixed with the pile fiber pieces, the grinding treatment can improve the lighting effect. The pile fiber pieces that are long enough to express the texture cannot be raised on the surface of the foam layer, and the appearance and feel of the resulting nubuck-like sheet can be impaired, the texture can become hard, There is a risk that a sufficient lighting effect may not be obtained. The viscosity of the prepolymer composition is determined by the temperature of the prepolymer composition, and the temperature of the prepolymer composition is determined by the heating and melting temperature of the prepolymer, the heating (melting) temperature of the urethane curing agent, the temperature of the prepolymer and the urethane curing agent. It is determined by the mixing ratio (further, the amount of heat generated by the reaction between the prepolymer and the urethane curing agent), the heating temperature of the mixing head, and the like. Especially, the influence of the pre-heating temperature of the prepolymer is large. The temperature of the prepolymer composition is usually 30 to 150 ° C., more preferably 40 to 120 ° C.

  The prepolymer composition is applied to either the releasable substrate or the pile fiber single side of the fibrous substrate. That is, when laminating a foam layer on one side of a pile fiber of a fibrous base material, the prepolymer composition is applied to (a) a releasable base material, and the pile of the fibrous base material is applied to the coated surface. A fiber single side may be bonded together, or (b) it may apply | coat to the pile fiber single side | surface of the said fibrous base material, and a release base material may be bonded together to this application surface. In the case of using a releasable substrate having a concavo-convex pattern for the purpose of improving the design properties, the step (a) is preferable because a clear concavo-convex pattern can be formed. Hereinafter, although it demonstrates along the process of (a), various description items, such as a coating method, are the matters which are common also when employ | adopting the process of (b) fundamentally.

  The releasable base material used in the present invention is not particularly limited, and may be a base material having releasability with respect to a polyurethane resin or a base material subjected to a release treatment. For example, release paper And a release treatment cloth, a water repellent treatment cloth, an olefin sheet or film made of polyethylene resin or polypropylene resin, a fluororesin sheet or film, a plastic film with release paper, and the like. The releasable base material may have a concavo-convex pattern. By using such a releasable base material, a foam layer having a concavo-convex pattern on the surface can be formed, thereby improving the design. Can do.

  A typical example of the concavo-convex pattern is a textured pattern. By using such a releasable base material, a high-grade nubuck-like appearance having a grainy texture pattern can be reproduced. In addition, the uneven pattern is not limited to a textured pattern, for example, a fabric pattern such as a fabric-like or denim-like pattern, or a geometrical combination of random dots, lines, rounds, triangles, squares, dotted lines, or the like. It can be a pattern like pattern.

  The height difference of the concavo-convex pattern of the releasable base material (corresponding substantially to the height difference of the concavo-convex pattern on the surface of the foam layer) is preferably 500 μm or less, and more preferably 10 to 200 μm. When the height difference exceeds 500 μm, the prepolymer composition does not reach the details of the concavo-convex pattern of the releasable substrate, and the desired concavo-convex pattern may not be obtained.

  Since the uneven pattern formed on the surface of the foam layer by using the release paper having the uneven pattern is formed simultaneously with the formation of the foam layer, there is no need to separately provide an embossing treatment as in the wet method or the dry method. The process is simple and low cost.

  As a method for applying the prepolymer composition to the releasable substrate, various conventionally known methods can be adopted and are not particularly limited. For example, it is applied to the releasable substrate using a roll coater, spray coater, T-die coater, knife coater or comma coater. In particular, coating with a knife coater or a comma coater is preferable because a uniform thin film layer can be formed.

  The coating thickness of the prepolymer composition varies depending on the length and density of the pile fiber pieces of the fibrous base material, and the height difference of the concavo-convex pattern of the releasable base material, but is preferably 25 to 900 μm, More preferably, it is -500 micrometers. By setting the coating thickness within the above range, a foamed layer having a thickness of 1.1 to 3.5 times, more preferably 1.2 to 3.2 times the coating thickness can be obtained in a normal case. The foamed layer has a thickness of preferably 27 to 1000 μm, more preferably 60 to 750 μm (described later). In addition, the thickness of a foaming layer here means the thickness before a grinding process.

  Next, while the prepolymer composition maintains the viscosity at the time of application, the pile surface of the fibrous base material is bonded to the coated surface, cooled to room temperature, and subjected to an aging treatment, whereby a fibrous base material is obtained. A foam layer is formed on one side of the pile fiber of the material.

  When laminating the prepolymer composition and the fibrous base material, the prepolymer is brought to the extent that the tip of the pile fiber piece reaches the releasable base material or a position as close as possible to the releasable base material. It is preferred that the composition penetrates into the pile fiber pieces. Insufficient penetration results in an increase in the thickness of the foam layer that is not mixed with the pile fiber pieces.As a result, the pile fiber pieces that are long enough to produce a lighting effect are ground on the surface of the foam layer. There is a possibility that the nubuck-like sheet-like material obtained cannot be protruded in a nap-like shape, and the appearance and feel of the resulting nubuck-like sheet material may be impaired, the texture may become hard, or a sufficient writing effect may not be obtained. The prepolymer composition (having a releasable substrate on one side thereof) is bonded to the fibrous base material, then increases in thickness toward the fibrous base material, and is mixed with the pile fiber pieces. A foam layer in a state is formed.

  A laminator is used for bonding. Of these, it is preferable to use a laminator having a temperature-adjustable roll because the penetration of the prepolymer composition can be easily controlled. At this time, it is preferable that roll temperature is 30-150 degreeC, and it is more preferable that it is 40-120 degreeC. When the roll temperature is less than 30 ° C., the prepolymer composition hardly penetrates into the pile fiber pieces of the fibrous base material, and as a result of increasing the thickness of the foam layer not mixed with the pile fiber pieces, , Pile fiber pieces that are long enough to produce a lighting effect cannot be raised on the surface of the foam layer, raising the appearance and feel of the nubuck-like sheet, resulting in a hard texture Or a sufficient lighting effect may not be obtained. When roll temperature exceeds 150 degreeC, there exists a possibility that the prepolymer composition may osmose | permeate a fiber base material excessively and the feel of the nubuck-like sheet-like material obtained may become hard.

  The reaction rate between the hot melt urethane prepolymer and the urethane curing agent varies greatly depending on the type and amount of the prepolymer, urethane curing agent, and optional additive (especially the urethanization catalyst) to be selected. It is necessary to appropriately set the aging treatment conditions, but in normal cases, it is performed at room temperature for about 1 day to 1 week. In this process, the curing reaction between the prepolymer and the urethane curing agent is completed. If the curing reaction is incomplete, physical properties, particularly wear resistance, may be deteriorated.

  The softening temperature of the polyurethane resin obtained by curing is preferably 130 to 240 ° C, and more preferably 140 to 200 ° C. If the softening temperature is less than 130 ° C., sufficient heat resistance may not be obtained. If the softening temperature exceeds 240 ° C, the texture may become hard.

  The thickness of the foamed layer before the grinding treatment (F, see FIG. 1 (B)) is preferably 27 to 1000 μm, and more preferably 60 to 750 μm. When the thickness of the foamed layer is in the above range, after the grinding treatment, the foamed layer preferably has a thickness of 17 to 800 μm, more preferably 40 to 650 μm (described later).

  The ratio of the thickness (F) of the foamed layer to the length (P) of the pile fiber pieces is preferably 30 to 120%, more preferably 50 to 100% from the tip of the pile fiber pieces ( (See FIG. 1B). If the ratio is less than 30%, the foamed layer may crack in the resulting nubuck-like sheet-like product, and the appearance and feel may be impaired, or a sufficient volume feeling may not be obtained. If the ratio exceeds 120%, the resulting nubuck-like sheet-like material may become hard.

  After the aging treatment, as shown in FIG. 1B, a laminate of a fibrous base material and a foamed layer in a state of being mixed with pile fiber pieces is obtained by peeling the releasable base material. Next, the exposed surface of the foam layer is ground, and the tip of at least a part of the pile fiber piece is protruded from the surface of the foam layer in a napped shape (see FIG. 1C). The grinding method is in principle the same as the above-described raising method, and grinding with a needle cloth or grinding with sandpaper is possible. Among them, a pile fiber piece that is capable of uniformly grinding the surface of the foam layer and that is long enough to exhibit a lighting effect and does not exhibit a suede-like appearance is used. Because of the fact that the surface can be protruded in the form of napped hair, a grinding process using a sand perper is preferable. Although it is as above-mentioned that the surface state can be suitably selected by selection of various conditions, the particle size of sandpaper is important among them, and the particle size defined by JIS R6252 is preferably 180-1500, 240-400 800 is more preferable. Here, it means that it is coarse, so that the numerical value of a particle size is small. If the particle size is less than 180, grinding lines are likely to occur, and the appearance of the resulting nubuck-like sheet may be impaired. When the particle size exceeds 1500, it may take a long time to obtain a desired surface state.

  The length of the pile fiber piece that protrudes from the surface of the foamed layer in a raised shape is preferably 10 to 300 μm, and more preferably 20 to 200 μm. If the length is less than 10 μm, the appearance of the resulting nubuck-like sheet may be impaired, or a sufficient lighting effect may not be obtained. When the length exceeds 300 μm, the suede appearance may be exhibited beyond the nubuck-like category.

  In this invention, the length of a pile fiber piece is calculated | required as follows. The vertical cross section of the nubuck-like sheet was observed with a microscope (manufactured by Keyence Corporation, Digital HF microscope VH-8000), the length was measured for any 10 pile fiber pieces, and the distribution (minimum value) ~ Average value) and average value. This average value is preferably within the above range, and more preferably both the maximum value and the minimum value are within the above range.

  The grinding thickness is adjusted so that the length of the pile fiber piece that protrudes in the napped shape on the surface of the foam layer falls within the above range. The grinding thickness varies depending on the length and density of the pile fiber pieces of the fibrous base material, the height difference of the concave and convex pattern in the case of using a releasable base material having the concave and convex pattern, and is 10 to 200 μm. Is preferable, and it is more preferable that it is 20-100 micrometers. If the grinding thickness is less than 10 μm, the appearance and feel of the resulting nubuck-like sheet-like material may be impaired, the texture may become hard, or a sufficient writing effect may not be obtained. If the grinding thickness exceeds 200 μm, the foam layer is cracked in the resulting nubuck-like sheet-like product, and the appearance and feel may be impaired. In the case of using a releasable base material having a concavo-convex pattern, it is more preferable to grind the foam layer so as to leave a concave portion formed thereby in order to enhance the nubuck-like appearance and feel. However, if the length of the pile fiber piece that protrudes on the surface of the foamed layer is within the above range, the pile that protrudes after grinding by the uneven pattern imparted at the time of forming the foamed layer, even if grinding is performed until the concave portion disappears Since the fiber piece is given a change corresponding thereto, a nubuck-like appearance and feel can be obtained.

The density of the pile fiber pieces to be protruded is preferably 25,000 to 3.5 million pieces / (25.4 mm) ² , more preferably 50,000 to 2.7 million pieces / (25.4 mm) ² , More preferably, it is 100,000 to 1,500,000 pieces / (25.4 mm) ² . If the density is less than 25,000 / (25.4 mm) ² , the appearance and feel of the resulting nubuck-like sheet may be impaired. When the density exceeds 3.5 million / (25.4 mm) ² , the texture of the resulting nubuck-like sheet may be hardened.

  The thickness of the foamed layer after the grinding treatment is preferably 17 to 800 μm, and more preferably 40 to 650 μm. If the thickness is less than 17 μm, a sufficient volume feeling may not be obtained. If the thickness exceeds 800 μm, the texture may become hard.

  The thickness of the sheet-like material after the grinding treatment is preferably 0.4 to 2.5 mm, and more preferably 0.6 to 2 mm. If the thickness is less than 0.4 mm, the texture of the resulting nubuck-like sheet may be paper-like, or a sufficient volume may not be obtained. If the thickness exceeds 2.5 mm, the texture of the nubuck-like sheet obtained may be hard.

  The nubuck-like sheet-like material of the present invention is a second resin layer or a second resin film in which the surface of a pile fiber piece protruding in a napped shape is coated with a protective film on the surface of the foam layer. Yes (see FIG. 1D). Thereby, the abrasion resistance of the nubuck-like sheet-like material obtained can be improved. Furthermore, depending on the resin used, the feel, that is, the slime feeling can be improved. In the present invention, the protective film is a general term for a resin film that covers the surface of each protruding pile fiber piece and protects the protruding pile fiber piece, and is composed of at least one layer of resin film. It can be composed of two or more resin films having the same or different compositions.

  Resin used for formation of a protective film is not specifically limited, What is necessary is just to select suitably from what is generally used. For example, a polyurethane resin, an acrylic resin, a polyvinyl chloride resin, a polyester resin, a polyamide resin, a silicone resin, and the like can be given, and these can be used alone or in combination of two or more. Especially, a polyurethane resin or an acrylic resin is preferable in terms of excellent film strength. The form of the resin may be either solvent-based or solvent-free, but a solvent-free system, particularly a water-based emulsion is preferable from the viewpoint of less environmental burden.

  For the resin forming the protective film, if necessary, a colorant, a matting agent, a smoothing agent, a crosslinking agent, an antifoaming agent, a foam stabilizer, a dispersing agent, an activator, as long as the physical properties of the resin are not impaired. Arbitrary components, such as 1 type, can be used individually by 1 type or in combination of 2 or more types. Among these, from the viewpoint of wear resistance, it is preferable to use a smoothing agent or a crosslinking agent as an additive.

  The protective film is formed by applying a resin composition to the surface of the protruding pile fiber piece and then performing a heat treatment. As the coating method, various conventionally known methods can be adopted and are not particularly limited. Examples thereof include a method using a reverse roll coater, spray coater, roll coater, gravure coater, kiss roll coater, knife coater, comma coater, and the like. Especially, application | coating with a spray coater is preferable at the point that a uniform thin film can be formed on the surface of the protruding pile fiber piece, without eliminating the nap by a pile fiber piece by embedding.

The coating amount of the resin composition is preferably 0.5 to 50 g / m ² in terms of solid content, and more preferably 1 to 15 g / m ² . If the coating amount is less than 0.5 g / m ² , the obtained nubuck-like sheet-like product may be deteriorated in wear resistance. If the coating amount exceeds 50 g / m ² , the naps due to the pile fiber pieces are buried in the resin and disappear, and the appearance and feel of the resulting nubuck-like sheet may be impaired.

  In the case of using a crosslinking agent that evaporates the solvent in the resin composition, dries the resin, and causes a crosslinking reaction by the heat treatment, the heat treatment accelerates the reaction and forms a film having sufficient strength. To be done. The heat treatment temperature is preferably 60 to 170 ° C, and more preferably 80 to 150 ° C. The heat treatment time is preferably 2 to 30 minutes, and preferably 5 to 10 minutes. If the heat treatment temperature is less than 60 ° C. or if the heat treatment time is less than 2 minutes, the resin may be insufficiently crosslinked and wear resistance may deteriorate. When the heat treatment temperature exceeds 170 ° C. or when the heat treatment time exceeds 30 minutes, the texture of the fibrous base material itself may become hard.

The thickness of the protective film thus formed is extremely thin and does not greatly affect the length and density of the pile fiber pieces and the thickness of the sheet-like material.
Thus, the nubuck-like sheet-like material of the present invention can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. “Parts” in the examples are based on weight. Moreover, evaluation of the obtained nubuck-like sheet-like material followed the following method.

[appearance]
Sensory evaluation was performed and judged according to the following criteria.
○: Delicate appearance of nubuck-like △: Slightly lacking nubuck-like appearance ×: No nubuck-like appearance at all, rough appearance

[Feel]
Sensory evaluation was performed and judged according to the following criteria.
○: Moist feel with nubuck tone △: Slightly lacking nubuck feel ×: No feel of nubuck tone, rough and dry feel

[Texture]
The bending resistance was measured as an index for texture evaluation, and judged according to the following criteria. In addition, the measurement of bending resistance was based on JIS L1096-1999 8.19.1 A method (45 degree cantilever method). Further, as the test piece, one having a width of 25 mm and a length of 200 mm, which was collected from the vertical direction and the horizontal direction, was used.
○: Bending softness is less than 60 mm and excellent in texture △: Bending softness is 60 mm or more and 80 mm or less and has a slightly hard texture ×: Bending softness exceeds 80 mm and texture is hard

[Lighting effect]
Place the sheet horizontally so that the longitudinal direction is up and down and the width direction is left and right. With a finger, trace the surface of the sheet-like material about 10 cm from top to bottom and from bottom to top at an angle of 60 degrees with respect to the width direction. Next, trace similarly at an angle of 45 degrees with respect to the width direction, and finally trace similarly at an angle of 30 degrees. The lighting effect at each angle was confirmed and judged according to the following criteria.
○: The lighting effect can be confirmed at any angle △: The lighting effect cannot be sufficiently confirmed at a specific angle ×: The lighting effect can hardly be confirmed at any angle

[Abrasion resistance]
A test piece T-TYPE with a width of 70 mm and a length of 300 mm is taken from the vertical direction and a urethane foam with a width of 70 mm, a length of 300 mm and a thickness of 10 mm is attached to the back surface. Fix to Daiei Kagaku Seiki Seisakusho Co., Ltd. A test piece is worn by applying a load of 9.8 N to a friction piece covered with cotton canvas. The friction element wears at a speed of 60 reciprocations per minute between 140 mm on the surface of the test piece. The cotton canvas is changed every 2500 times of wear, and wears a total of 10,000 times. The state of the test piece after abrasion was observed and judged according to the following criteria.
○: No cracks, tears, etc. △: Cracks occurred ×: Breaks occurred

Moreover, the hot-melt urethane prepolymer was produced as follows.
[Production Example 1]
Polycarbonate polyol having a number average molecular weight of 2000 (Kuraray Polyol P2012: made by Kuraray Co., Ltd.) and polycarbonate polyol having a number average molecular weight of 2000 (Kuraray Polyol C2090: stock) in a 1 liter four-necked flask kept at 60 ° C. 50 parts of Kuraray Co., Ltd. and 10 parts of polyether polyol (PTMG1000: manufactured by Sanyo Chemical Industries Co., Ltd.) having a number average molecular weight of 1000 are stirred, and then 15 parts of 4,4′-diphenylmethane diisocyanate (MDI). The mixture was stirred at 80 ° C. until the isocyanate group disappeared (equivalent ratio (hydroxyl group / isocyanate group) was 1.25) to obtain a hot melt urethane polyol prepolymer (softening temperature: 40 ° C.).

[Production Example 2]
10 parts of polyester polyol (Kuraray polyol P1012: manufactured by Kuraray Co., Ltd.) having a number average molecular weight of 1000 and 6 parts of 4,4′-diphenylmethane diisocyanate (MDI) are placed in a 1-liter four-necked flask kept at 60 ° C. The mixture was stirred at 80 ° C. until the hydroxyl group disappeared (equivalent ratio (isocyanate group / hydroxyl group) was 2.4) to obtain a hot melt urethane polyisocyanate prepolymer (softening temperature: 30 ° C.).

Moreover, the following polyurethane resin composition was used for formation of a protective film (each component of composition 1 and 2 is a product made from Stahl).
[Resin composition]
The solutions of Composition 1 and Composition 2 were mixed immediately before coating (total 430 parts) to obtain a resin composition.

Composition 1
HM-183 (smoothing agent) 5 parts HM-4986 (smoothing agent) 15 parts WT-2524 (polyurethane resin) 100 parts LA-1688 (activator) 20 parts Water 270 parts

Composition 2
XR-13-436 (crosslinking agent) 10 parts water 10 parts

[Example 1]
Using a tricot knitting machine with 28 gauges and 3 rivets, interlace yarn of polyethylene terephthalate 32dtex / 102f (single fiber fineness 0.31dtex) is used for the front heel, and polyethylene terephthalate 75dtex / 36f for the middle heel and back heel. The fabric is front 筬 1-0 / 3-4, middle 筬 1-0 / 1-2, back 筬 2-3 / 1-0, 70 course / 25.4mm tricot on knitting machine Knitted fabric.
The resulting knitted fabric was dyed using a disperse dye at 130 ° C. for 30 minutes with a liquid dyeing machine, then dried by heat treatment at 150 ° C. for 2 minutes using a heat setter.

Next, from a knitting end direction and a knitting start direction at a cloth roller torque of 2.5 MPa and a cloth speed of 12 m / min by a needle cloth raising machine having a needle cloth roll having twelve pile rollers and twelve counter pile rollers. Brushing was performed 13 times alternately, and semi-cut brushing was performed so that about 50% of the front yarn was cut. Subsequently, it heat-processed at 190 degreeC with the heat setter for 1 minute, and was finished. The resulting pile pile fabric had a knitting density of 38 wale / 25.4 mm, 64 course / 25.4 mm, and a thickness of 1.0 mm. Moreover, the length of the pile fiber piece was 0.6 mm, and the density of the pile fiber piece was 480,000 pieces / (25.4 mm) ² . Such a raised pile knitted fabric was used as a fibrous base material.

  100 parts of the hot melt urethane polyol prepolymer of Production Example 1 heated and melted to 100 ° C. as a hot melt urethane prepolymer, 20 parts of the hot melt urethane polyisocyanate prepolymer of Production Example 2 heated to 40 ° C. as a urethane curing agent, Add 10 parts of carbon black pigment Polyton Black (Dainippon Ink Chemical Co., Ltd.) as a colorant and 1 part of an amine catalyst TOYOCAT-DT (Tosoh Corporation) as a urethanization catalyst. A composition (equivalent ratio (isocyanate group / hydroxyl group) was 1.1) was prepared. The temperature of the prepolymer composition was 75 ° C. and the viscosity was 5000 cps. Sheet of this prepolymer composition on a release paper DE-146 (manufactured by Dai Nippon Printing Co., Ltd.) having a grainy uneven pattern (height difference: 20 to 60 μm) with a comma coater so that the coating thickness becomes 200 μm. It was applied to the shape.

  Next, while the prepolymer composition maintained the viscosity at the time of application, the pile fiber one side of the fibrous base material was bonded together and pressed with a 0.5 MPa load with a roll adjusted to 80 ° C. Subsequently, the sheet-like material was wound up and aged at room temperature for 1 day, and then the release paper was peeled off. In the obtained laminate of the fibrous base material and the foam layer, the softening temperature of the polyurethane resin constituting the foam layer is 200 ° C., the thickness of the foam layer is 480 μm, the thickness of the foam layer relative to the length of the pile fiber piece The ratio was 80% from the tip of the pile fiber piece.

Next, the surface of the foam layer was ground by 50 μm at a paper speed of 1000 m / min by a buffing machine equipped with sandpaper having a particle size of No. 400, and the tip of the pile fiber piece was protruded in a raised shape on the surface of the foam layer. At this time, the length distribution of the protruding pile fiber pieces was 60 to 180 μm, the average value was 120 μm, the density of the pile fiber pieces was 400,000 pieces / (25.4 mm) ² , and the thickness of the foam layer was 430 μm. . Moreover, the thickness of the sheet-like material was 1.0 mm.

Next, a polyurethane resin composition for forming a protective film was applied with a spray coater so that the coating amount was 7 g / m ^2, and heat-treated at 100 ° C. for 2 minutes with a heat setter. A protective film to be coated was formed, and the nubuck-like sheet-like material of Example 1 was obtained.

[Comparative Example 1]
As the constituent fibers of the nonwoven fabric, ultrafine polyethylene terephthalate with a single fiber fineness of 0.15 dtex cut by direct spinning method to 5 mm length and ultrafine polyethylene terephthalate with single fiber fineness of 0.1 dtex by direct spinning method cut to 5 mm length This was dispersed in water so that the weight ratio was 50:50, and a slurry for papermaking for the surface layer and the back layer was produced. A gauze-like woven fabric made of yarn of polyethylene terephthalate 165 dtex / 48f was enclosed in the middle with a surface layer basis weight of 110 g / m ² and a back layer basis weight of 60 g / m ^2, and a nonwoven fabric having a three-layer laminated structure was produced by continuous papermaking.
A high-speed water stream was jetted onto the obtained nonwoven fabric to obtain a three-dimensional entangled nonwoven fabric. For high-speed water flow, a straight flow jet nozzle having a hole diameter of 0.1 mm was used, and jet treatment was performed at a pressure of 4.0 MPa from the surface layer and 3.0 MPa from the back layer. Subsequently, it heat-dried at 150 degreeC with the heat setter for 1 minute, and dried.

Next, the surface layer of the three-dimensional entangled nonwoven fabric was brushed at a paper speed of 1000 m / min with a buffing machine equipped with sandpaper having a particle size of No. 400. The thickness of the obtained raised pile nonwoven fabric was 1.0 mm. Moreover, the length of the pile fiber piece was 0.5 mm, and the density of the pile fiber piece was 1.06 million pieces / (25.4 mm) ² .

After the impregnated pile nonwoven fabric was impregnated with a treatment solution containing 40% by weight of Evaphanol APC-55 (manufactured by Nikka Chemical Co., Ltd.) as a water-based polycarbonate polyurethane emulsion and 3% by weight of sodium sulfate as a heat sensitive agent, a pickup rate of 120 The film was squeezed with mangles to a weight% (the solid polyurethane adhesion rate of 17% by weight), and then dried by heat treatment at 130 ° C. for 3 minutes with a heat setter.
Next, after using a disperse dye for dyeing at 130 ° C. for 20 minutes with a liquid dyeing machine, heat treatment is performed for 2 minutes at 150 ° C. with a heat setter, and drying is performed. Sheet-like material of Comparative Example 1 (which is a form of a dry method) Got. The length distribution of the pile fiber pieces was 200 to 300 μm, the average value was 250 μm, and the density of the pile fiber pieces was 1.06 million / (25.4 mm) ² . Moreover, the thickness of the sheet-like material was 1.0 mm.

[Example 2]
A sheet-like material was obtained in the same manner as in Comparative Example 1 except that the concentration of the aqueous polycarbonate polyurethane emulsion of the treatment liquid impregnated into the raised pile nonwoven fabric was 9% by weight. The thickness of the sheet was 1.0 mm, the length distribution of the pile fiber pieces was 200 to 300 μm, the average value was 250 μm, and the density of the pile fiber pieces was 1.06 million pieces / (25.4 mm) ^2. It was.
The nubuck-like sheet of Example 2 was used in the same manner as in Example 1 except that such a sheet-like material was used as a fibrous base material, the coating thickness of the prepolymer composition was 100 μm, and the grinding thickness of the foamed layer was 35 μm. A product was obtained. The thickness of the foamed layer before the grinding treatment was 300 μm, and the ratio of the thickness of the foamed layer to the length of the pile fiber piece was 90% from the tip of the pile fiber piece. The length distribution of the pile fiber pieces protruding from the surface of the foamed layer by the grinding treatment is 20 to 50 μm, the average value is 30 μm, the density of the pile fiber pieces is 900,000 pieces / (25.4 mm) ² , The thickness was 265 μm. Moreover, the thickness of the sheet-like material was 1.0 mm.

[Example 3]
Example 1 except that a polyethylene terephthalate 75dtex / 144f (single yarn fineness 0.52 dtex) yarn was used for the front heel, and the number of raising was 5 and semi-cut raising was performed so that about 7% of the front yarn was cut. In the same manner, a brushed pile knitted fabric was obtained. The resulting pile pile fabric had a knitting density of 38 wale / 25.4 mm, 64 course / 25.4 mm, and a thickness of 1.0 mm. Moreover, the length of the pile fiber piece was 0.6 mm, and the density of the pile fiber piece was 50,000 pieces / (25.4 mm) ² .
A nubuck-like sheet-like material of Example 3 was obtained in the same manner as in Example 1 except that such a raised pile knitted fabric was used as a fibrous base material and the coating thickness of the prepolymer composition was 150 μm. The thickness of the foamed layer before the grinding treatment was 375 μm, and the ratio of the thickness of the foamed layer to the length of the pile fiber piece was 110% from the tip of the pile fiber piece. The length distribution of the pile fiber pieces protruding from the surface of the foamed layer by the grinding treatment is 25 to 75 μm, the average value is 50 μm, the density of the pile fiber pieces is 430,000 / (25.4 mm) ² , The thickness was 325 μm. Moreover, the thickness of the sheet-like material was 1.0 mm.

[Example 4]
Polyethylene terephthalate 125dtex / 180f (single fiber fineness 0.69dtex) yarn is used for the front heel, middle heel and polyethylene terephthalate 33dtex / 12f yarn are used for the back heel, and the structure is the front heel 1-0 / 4-5, middle heel A raised pile knitted fabric was obtained in the same manner as in Example 1 except that 1-0 / 1-2 and the back tack 2-3-1-0 were used. The resulting pile pile fabric had a knitting density of 30 wale / 25.4 mm, 70 course / 25.4 mm, and a thickness of 2.5 mm. Moreover, the length of the pile fiber piece was 2.0 mm, and the density of the pile fiber piece was 750,000 pieces / (25.4 mm) ² .
A nubuck-like sheet-like material of Example 4 was obtained in the same manner as in Example 1 except that such a raised pile knitted fabric was used as a fibrous base material and the coating thickness of the prepolymer composition was 500 μm. The thickness of the foamed layer before the grinding treatment was 750 μm, and the ratio of the thickness of the foamed layer to the length of the pile fiber piece was 50% from the tip of the pile fiber piece. The length distribution of the pile fiber pieces protruding from the surface of the foam layer by grinding treatment is 40 to 160 μm, the average value is 100 μm, the density of the pile fiber pieces is 640,000 pieces / (25.4 mm) ² , The thickness was 700 μm. Moreover, the thickness of the sheet-like material was 2.5 mm.

[Example 5]
Until the raising by the needle cloth raising machine, the prepolymer composition similar to that of Example 1 is applied to the raising surface (pile fiber one side) of the raising pile knitted fabric obtained in the same manner as in Example 1 so that the coating thickness becomes 200 μm. It was applied in a sheet form with a doctor knife coater. Next, release paper DE-146 (Dai Nippon Printing Co., Ltd.) having a textured uneven pattern (height difference: 20 to 60 μm) is bonded to the prepolymer composition while maintaining the viscosity at the time of application. And a roll adjusted to 80 ° C. with a load of 0.5 MPa.
Thereafter, the nubuck-like sheet-like material of Example 5 was obtained in the same manner as Example 1. The thickness of the foamed layer before the grinding treatment was 400 μm, and the ratio of the thickness of the foamed layer to the length of the pile fiber piece was 100% from the tip of the pile fiber piece. The length distribution of the pile fiber pieces protruding from the surface of the foamed layer by the grinding treatment is 60 to 180 μm, the average value is 120 μm, the density of the pile fiber pieces is 400,000 pieces / (25.4 mm) ² , The thickness was 350 μm. Moreover, the thickness of the sheet-like material was 1.0 mm.

[Comparative Example 2]
Up to the raising with a buffing machine, the raised pile nonwoven fabric obtained in the same manner as in Comparative Example 1 was impregnated with a treatment liquid containing 6% by weight of GL-05 (manufactured by Nippon Synthetic Chemical Co., Ltd.) as polyvinyl alcohol, and then the pickup rate was 100% by weight. It was squeezed with mangles so that the solid content adhesion rate of polyvinyl alcohol was 6% by weight, and then dried by heat treatment at 130 ° C. for 3 minutes with a heat setter.
Next, after impregnating a treatment liquid containing 12% by weight of Crisbon MP-145 (manufactured by Dainippon Ink & Chemicals, Inc.) as a solvent-based polyether / polyester polyurethane resin, it is immersed in water and solidified, and then heated at 150 ° C. with a heat setter. And dried for 2 minutes by heat treatment.
Next, after dyeing at 130 ° C. for 20 minutes with a liquid dyeing machine using a disperse dye, the sheet is dried by heat treatment at 150 ° C. for 2 minutes with a heat setter (this is one form of a wet method). Got. The length distribution of the pile fiber pieces was 150 to 250 μm, the average value was 200 μm, the density of the pile fiber pieces was 1.06 million pieces / (25.4 mm) ² , and the thickness of the foamed layer was 300 μm. Moreover, the thickness of the sheet-like material was 1.0 mm.

[Comparative Example 3]
100 parts of Crisbon NY-328 (manufactured by Dainippon Ink & Chemicals, Inc.) as a solvent-based polycarbonate polyurethane resin, 20 parts of black pigment Dilac L-1770S (manufactured by Dainippon Ink & Chemicals, Inc.) as a colorant, a diluent solvent A release paper UM-11E having a nubuck-like concavo-convex pattern (height difference: 20 to 60 μm) obtained by mixing 20 parts of N, N-dimethylformamide (DMF) and 20 parts of methyl ethyl ketone (MEK) as a diluent. (Dai Nippon Printing Co., Ltd.) is coated with a comma coater so that the coating thickness is 200 μm, heat-treated with a heat setter at 150 ° C. for 2 minutes, and dried to form a film with a thickness of 40 μm for skin formation. Obtained. Furthermore, 100 parts of polycarbonate-based polyurethane resin Crisbon TA-205 (manufactured by Dainippon Ink & Chemicals, Inc.) as an adhesive and 10 parts of Barnock DN-950 (manufactured by Dainippon Ink & Chemicals, Inc.) as a crosslinking agent are formed on the surface. A solution obtained by mixing 40 parts of DMF as a diluent solvent and 20 parts of MEK as a diluent was applied to a coating thickness of 200 μm, heat-treated at 100 ° C. for 2 minutes, and dried.
Next, the same fibrous base material as in Example 1 was pressed and bonded with a roll adjusted to 80 ° C. with a load of 0.5 MPa. Subsequently, the release paper was peeled off to obtain a sheet-like material (thickness: 1.0 mm) of Comparative Example 3.

[Comparative Example 4]
A sheet-like material of Comparative Example 4 was obtained in the same manner as in Example 1 except that the protective film was not formed.

[Comparative Example 5]
The same tricot knitting machine as in Example 1 was used, a polyethylene terephthalate 84dtex / 72f (single yarn fineness 1.17 dtex) interlaced yarn was used for the front heel, and a polyethylene terephthalate 84dtex / 36f yarn was used for the middle heel. A pole bar is arranged on the heel, the organization is front 筬 0-1 / 1-0, middle 筬 1-0 / 1-2, back 筬 0-0 / 1-1, 50 courses / 25 on the knitting machine A tricot knitted fabric having a loop pile at 4 mm was knitted.
The resulting knitted fabric was dyed using a disperse dye at 130 ° C. for 30 minutes with a liquid dyeing machine, then dried by heat treatment at 150 ° C. for 2 minutes using a heat setter. The obtained loop pile knitted fabric had a knitting density of 36 wals / 25.4 mm, 56 courses / 25.4 mm, and a thickness of 1.5 mm. The length of the pile yarn (the length from the engaging portion of the loop pile with the ground structure to the top of the loop) was 1.0 mm, and the density of the pile yarn was 2016 / (25.4 mm) ² .
A sheet-like material (thickness: 1.5 mm) of Comparative Example 5 was obtained in the same manner as in Example 1 except that this loop pile knitted fabric was used as the fibrous base material. However, the grinding process could not be performed satisfactorily, and the tip of the pile fiber piece could not be protruded in a napped shape on the surface of the foam layer.

[Comparative Example 6]
Up to the raising by the needle cloth raising machine, 40% by weight of Evaphanol APC-55 (manufactured by Nikka Chemical Co., Ltd.) as a water-based polycarbonate polyurethane emulsion was added to the raised tricot knitted fabric obtained in the same manner as in Example 1, and sulfuric acid as a heat-sensitive agent. After impregnating with a treatment solution containing 3% by weight of sodium, it is squeezed with mangles so that the pickup rate is 120% by weight (the solid polyurethane adhesion rate is 17% by weight), and then heat treated at 130 ° C. for 3 minutes with a heat setter. Dried.
Next, after forming a leather draw pattern by embossing at 80 ° C. for 5 seconds with a hydrick type embossing machine, grinding treatment was performed in the same manner as in Example 1, and a protective film was further formed. Comparative Example 6 Sheet material (thickness: 0.5 mm) was obtained. However, the grinding process could not be performed satisfactorily, and the tip of the pile fiber piece could not be protruded in a napped shape on the surface of the foam layer.

  Table 1 shows the results of evaluating the performance of the nubuck-like sheet-like materials of the above Examples and Comparative Examples.

Claims (3)

  It is formed on the surface of the fibrous base material having pile fiber pieces made of non-wound-like pile fibers on at least one surface by the reaction of a hot melt urethane prepolymer and a urethane curing agent. The foam layer made of polyurethane resin is laminated in a state of being mixed with the pile fiber pieces, and at least a part of the pile fiber pieces protrudes in a raised shape on the surface of the foam layer, and the surface of the protruding pile fiber pieces is A nubuck-like sheet covered with a protective film. The nubuck according to claim 1, wherein the length of the pile fiber piece protruding from the surface of the foam layer is 10 to 300 µm and the density is 25,000 to 3.5 million pieces / (25.4 mm) ^2. Toned sheet. A step of preparing a prepolymer composition by mixing a hot melt urethane prepolymer in a heat-melted state and a urethane curing agent,
The pile fiber of a fibrous base material, which is obtained by applying a prepolymer composition to (a) a releasable base material and having pile fiber pieces made of non-round pile fibers on at least one side of the coated surface. The surface on the side having the piece is bonded together, or (b) the surface on the side having the pile fiber piece of the fibrous base material having the pile fiber piece made of non-round pile fiber on at least one surface. Applying, and bonding the releasable substrate to the coated surface;
A step of aging treatment to form a foam layer made of polyurethane resin,
A step of peeling the releasable substrate,
A step of grinding the surface of the foam layer to project at least a part of the tip of the pile fiber piece into the surface of the foam layer in a raised shape,
Applying a resin composition to the surface of the protruding pile fiber pieces;
A step of heat-treating to form a protective film covering the surface of the protruding pile fiber pieces;
A method for producing a nubuck-like sheet material comprising

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