JP2016006241A - Artificial leather substrate, artificial leather and leather-like three-dimensional molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial leather superior in contact cold feeling.SOLUTION: A artificial leather substrate contains a fiber entangled body, and a high heat conductance filler having a heat conductivity not less than 1 W/mK and liquid non-volatile oil, the fiber entangled body being impregnated with the high heat conductance filler and the non-volatile oil. At least one face of the artificial leather substrate has a contact cold feeling not less than 0.25 W/cmas a maximum heat absorption rate (q-max value).

Description

  The present invention relates to an artificial leather having excellent contact cold / hot feeling performance.

  Conventionally, artificial leather including a nonwoven fabric which is a fiber entangled body is known. Artificial leather is used as an alternative to natural leather in fields such as shoes, clothing, gloves, bags, balls, interiors, and vehicles.

  Artificial leather is manufactured by applying a surface treatment for imparting a desired appearance to an artificial leather base obtained by impregnating a void inside a nonwoven fabric with a polymer elastic body. The polymer elastic body gives a sense of fulfillment to the nonwoven fabric. As artificial leather, for example, silver-added artificial leather with a silver-like appearance, suede-like or nubuck-like artificial leather with fluffed fibers on the surface of a nonwoven fabric, and the like are known.

  Natural leather has a high level of flexibility and flexibility because it contains dense collagen fibers. The high sense of fullness of natural leather, when bent, forms a fine crease that is rounded and has a high-class feel, and also exhibits excellent drape.

  However, natural leather has been difficult to use in applications that require heat resistance and water resistance, such as automobile seats. This is because collagen fibers are inferior in heat resistance and water resistance.

  On the other hand, artificial leather is superior in heat resistance, water resistance, quality stability and wear resistance to natural leather, and is easy to care for. However, since artificial leather has voids that are not filled with a polymer elastic body in the nonwoven fabric, it is inferior in density and fullness compared to natural leather. For this reason, when the artificial leather is bent, it is not rounded and bent like natural leather, but bends and bends so as to be called “boiled”. Such bending is not high-class. In order to eliminate such breakage, there is also known a method of highly filling the voids by increasing the content ratio of the polymer elastic body in the nonwoven fabric. However, when the voids are reduced by highly filling the polymer elastic body, the feeling of rebound becomes high and a rubber-like rigid texture is obtained.

  By the way, artificial leather is widely used for applications such as shoes, clothing, gloves, and sheets that come into contact with human skin. For example, a three-dimensional molded body of artificial leather is used for the skin of a shoe using artificial leather. The feet of a person wearing artificial leather shoes touch the molded artificial leather. In such a shoe, the body temperature of the foot accumulates in the shoe during walking, which may cause discomfort to the person. In addition, for example, in a seat seat of an automobile, there has been a demand for a seat that does not accumulate heat on the seating surface and gives a cool feeling to a person when sitting.

  Patent Document 1 listed below is a skin material used for interior materials such as automobile seats and interior materials such as skins for sofas and chairs, and is not easily affected even when exposed to extreme temperatures. The skin material which has the feeling of contact cold temperature which is hard to feel a temperature change even if it contacts is disclosed. Specifically, it is a skin material in which a porous heat insulating layer and a colored layer are sequentially laminated on a fibrous base material, the skin material having irregularities on the surface of the skin material, and a contact area ratio on the surface of the skin material of 65% or less. Is disclosed. This technique is a technique for reducing the thermal conductivity of the skin material.

JP 2014-12914 A

  The present invention provides an artificial leather excellent in contact cold / hot feeling performance.

One aspect of the present invention includes a fiber entangled body, a highly thermally conductive filler having a thermal conductivity of 1 W / mK or more, and a liquid non-volatile oil impregnated in the fiber entangled body. Is an artificial leather substrate having a maximum heat absorption rate (q-max value) of 0.25 W / cm ² or more. Such an artificial leather base material gives a feeling of cooling because the high thermal conductivity filler quickly takes away the body temperature when a person touches the surface. In addition, the liquid non-volatile oil contributes to keeping the high thermal conductive filler in the fiber entangled body while maintaining the flexibility without making the texture hard as in the case of using a polymer elastic binder.

When the artificial leather base material has a heat retention rate of 25% or less according to JIS L1096 heat retention property “A method” on the surface having a q-max value of 0.25 W / cm ² or more. Is preferable because the heat retaining property is not too high and the contact cold / warm feeling performance is excellent.

Moreover, when 3-30 mass parts of high heat conductive fillers are contained with respect to 100 parts by mass of the fiber entangled body, it is easy to secure a heat conduction path by sufficiently maintaining the contact between the particles of the high heat conductive filler. Therefore, the q-max value is preferable because it can be easily adjusted to 0.25 W / cm ² or more and a heat retention rate of 25% or less.

  Moreover, when it contains the quantity of highly heat conductive fillers equivalent to 1 mass part or more in conversion of a metal element with respect to 100 mass parts of fiber entangled bodies, it is especially preferable from the point which is excellent in thermal conductivity. In addition, the amount corresponding to 1 part by mass or more in terms of metal element is calculated by multiplying the mass part of the high thermal conductive filler contained by a metal element content ratio that varies depending on the type of the high thermal conductive filler.

  As the non-volatile oil, liquid paraffin, silicone oil, mineral oil, phthalates and the like are preferably used.

Moreover, when it has an apparent density of 0.55 g / cm ³ or more, it is easy to maintain sufficient contact between the particles of the high thermal conductive filler and that there are fewer voids that hinder thermal conductivity, The q-max value is preferable because it can be easily adjusted to 0.25 W / cm ² or more and a heat retention rate of 25% or less.

  Another aspect of the present invention is an artificial leather including the artificial leather base as described above.

  Another aspect of the present invention is a leather-like three-dimensional molded article obtained by imparting a three-dimensional shape to the artificial leather as described above by hot pressing. Since the artificial leather base as described above is excellent in thermal conductivity, in order to quickly dissipate the heat applied from the mold during hot pressing, the fiber entangled body contained in the artificial leather base is used. Heat is less likely to accumulate and the fibers are less likely to fuse. Therefore, the molded product obtained after hot pressing does not become hard, and a soft texture is easily maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the artificial leather excellent in the contact cold / hot feeling performance is obtained.

Hereinafter, an embodiment of an artificial leather base material according to the present invention will be described in detail. The artificial leather base material of this embodiment includes a fiber entanglement of ultrafine fibers having a fineness of 0.9 dtex or less, a high thermal conductivity filler impregnated in the fiber entanglement and having a thermal conductivity of 1 W / mK or more, and a liquid non-volatile property. The feeling of contact cold / warm on at least one surface is 0.25 W / cm ² or more as the maximum heat absorption rate (q-max value).

  Hereinafter, the artificial leather base material of the present embodiment will be described in detail along an example of the manufacturing method thereof.

  The fiber entangled body is not particularly limited as long as it is a fiber structure such as nonwoven fabric, woven fabric, woven fabric, or knitted fabric. Among these, nonwoven fabrics, particularly nonwoven fabrics of ultrafine fibers are preferable. Since the nonwoven fabric of ultrafine fibers has a dense fiber density, it is easy to hold a highly heat-conductive filler and liquid nonvolatile oil inside. In addition, the density unevenness of the fibers is low and the homogeneity is high. Therefore, an artificial leather excellent in contact cold / warm feeling performance and excellent in flexibility and high sense of fullness can be obtained. In the present embodiment, the case where a non-woven fabric of ultrafine fibers is used as the fiber entanglement will be described in detail as a representative example.

  The nonwoven fabric of ultrafine fibers can be obtained, for example, by entanglement treatment of ultrafine fiber-generating fibers such as sea-island type (matrix-domain type) composite fibers and the ultrafine fiber treatment. In the present embodiment, the case where the sea-island type composite fiber is used will be described in detail. However, even if an ultrafine fiber-generating fiber other than the sea-island type composite fiber is used, it is directly used without using the ultrafine fiber-generating fiber. Ultra fine fibers may be spun. In addition, as a specific example of the ultrafine fiber generation type fiber other than the sea-island type composite fiber, a plurality of ultrafine fibers are formed by lightly bonding immediately after spinning, and a plurality of ultrafine fibers are formed by unraveling by mechanical operation. Such as a split-divided fiber, or a petal-type fiber in which a plurality of resins are alternately gathered in a petal shape in the melt spinning process, and any fiber that can form ultrafine fibers is used without particular limitation. It is done.

  In the production of the ultrafine fiber nonwoven fabric, the island of the sea-island type composite fiber that is the resin component that forms the sea component (matrix component) of the sea-island type composite fiber that can be selectively removed and the resin component that forms the ultrafine fiber are first introduced. A sea-island type composite fiber is obtained by melt spinning and stretching a thermoplastic resin constituting the component (domain component).

  As the sea component thermoplastic resin, a thermoplastic resin having a different solubility in a solvent or a decomposability in a decomposing agent is selected from the island component resin. Specific examples of the thermoplastic resin constituting the sea component include, for example, a water-soluble polyvinyl alcohol resin, polyethylene, polypropylene, polystyrene, ethylene propylene resin, ethylene vinyl acetate resin, styrene ethylene resin, styrene acrylic resin, and the like. .

  The thermoplastic resin, which is a resin component that forms island components and forms ultrafine fibers, is not particularly limited as long as it is a resin capable of forming sea-island composite fibers and ultrafine fibers. Specifically, for example, polyethylene terephthalate (PET), isophthalic acid modified PET, sulfoisophthalic acid modified PET, polybutylene terephthalate, polyhexamethylene terephthalate and other aromatic polyesters; polylactic acid, polyethylene succinate, polybutylene succinate, Aliphatic polyesters such as polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate resin; polyamides such as polyamide 6, polyamide 66, polyamide 10, polyamide 11, polyamide 12, polyamide 6-12; polypropylene, polyethylene, polybutene , Polyolefins such as polymethylpentene and chlorinated polyolefin. These may be used alone or in combination of two or more.

  As a method for producing a nonwoven fabric of ultrafine fibers, for example, a sea-island composite fiber is melt-spun to produce a web, the web is entangled, and then sea components are selectively removed from the sea-island composite fiber. The method of forming is mentioned. As a method for producing a web, a long-fiber sea-island composite fiber spun by a spunbond method or the like is collected on a net without being cut to form a long-fiber web, or a long fiber is cut into staples. And a method of forming a short fiber web. Among these, a long fiber web is particularly preferable because it is excellent in denseness and fullness. In addition, the formed web may be subjected to a fusion treatment in order to impart shape stability.

  In addition, a long fiber means a continuous fiber that is not a short fiber intentionally cut after spinning. More specifically, for example, it means a fiber that is not a short fiber intentionally cut so that the fiber length is about 3 to 80 mm. It is preferable that the fiber length of the sea-island type composite fiber before the ultrafine fiber formation is 100 mm or more, and it can be technically manufactured and unavoidably cut in the manufacturing process. The fiber length may be km or more. In addition, a part of long fiber may be inevitably cut | disconnected and become a short fiber in a manufacturing process by the needle punch at the time of the entanglement mentioned later, or buffing of the surface.

  Sea island type composite fiber is densified by performing fiber shrinkage treatment such as entanglement treatment and heat shrink treatment with water vapor in any process from removing sea components of sea island type composite fiber to forming ultra fine fiber can do. Examples of the entanglement treatment include a method of stacking about 5 to 100 webs and performing needle punching or high-pressure water flow treatment.

  The sea component of the sea-island type composite fiber is removed by dissolution or decomposition at an appropriate stage after the web is formed. By such decomposition removal or dissolution extraction removal, the sea-island type composite fibers are made into ultrafine fibers, and fiber bundle-like ultrafine fibers are formed.

  The fineness of the ultrafine fiber is not particularly limited, but is preferably 0.9 dtex or less, more preferably 0.01 to 0.6 dtex, and particularly preferably 0.02 to 0.5 dtex. When the fineness is too high, there is a tendency that a non-woven fabric with insufficient density is obtained. Moreover, it is difficult to produce a fiber having a fineness that is too low. Moreover, there exists a tendency for fibers to converge and the rigidity of a nonwoven fabric to become high.

  The ultrafine fiber nonwoven fabric thus obtained is subjected to thickness adjustment and flattening treatment as necessary. Specifically, slice processing and buffing processing are performed. In this way, a non-woven fabric of ultrafine fibers that is a fiber entangled body is obtained.

Although the thickness of a fiber entangled body is not specifically limited, It is preferable that it is about 100-3000 micrometers, Furthermore, about 300-2000 micrometers. Further, the apparent density of the fiber entangled body is not particularly limited, but is 0.25 to 0.70 g / cm ³ , further 0.45 to 0.65 g / cm ³ , particularly 0.55 to 0.60 g / cm. ³ is preferable from the viewpoint of obtaining an artificial leather base material having both a sense of fulfillment and a supple texture.

  Next, the process of impregnating the voids of the fiber entangled body with a high thermal conductivity filler having a thermal conductivity of 1 W / mK or more (hereinafter also simply referred to as a high thermal conductivity filler) and liquid nonvolatile oil will be described.

  In this step, first, a dispersion containing a highly thermally conductive filler and nonvolatile oil is prepared.

  In the dispersion, for example, a highly heat-conductive filler and liquid nonvolatile oil are homogeneously mixed and dispersed in a dispersion medium such as water or a mixture of water and a polar solvent such as alcohol.

  Examples of the highly thermally conductive filler in the present embodiment include metal particles and inorganic fillers having a thermal conductivity of 1 W · cm · ° C. or higher.

  The thermal conductivity of the high thermal conductive filler is preferably 1 W / mK or higher, sufficiently higher than that of the resin component forming the fiber entangled body, preferably 10 W / mK or higher, and more preferably 15 W / mK or higher. . Moreover, as a particle diameter of a highly heat conductive filler, it is preferable that it is an average particle diameter of 0.1-15 micrometers, Furthermore, an average particle diameter is about 0.5-10 micrometers.

Specific examples of metal particles having a thermal conductivity of 1 W / mK or more include magnesium oxide (45-60 W / mK, MgO), alumina (20-35 W / mK, Al ₂ O ₃ , titanium dioxide (21.9 W / mK). TiO ₂ )), aluminum nitride (150-250 W / mK, AlN), zinc oxide (25.2 W / mK, ZnO), cerium dioxide (11.3 W / mK, CeO ₂ ), etc., or silica (1 .38 W / mK, SiO ₂ ) and other metalloid compound fillers. These may be used alone or in combination of two or more. Among these, alumina is preferable because it is inexpensive and has excellent thermal conductivity.

  The liquid non-volatile oil in the present embodiment is a liquid having a boiling point of 150 ° C. or higher and substantially not dissolved in a polar solvent. Specific examples include liquid paraffin, paraffinic or naphthenic process oil, mineral oil, silicone oil, and phthalates. These may be used alone or in combination of two or more. Among these, liquid paraffin is preferable because it is excellent in chemical stability and hardly oxidized.

  Further, the voids of the fiber entangled body may be impregnated with a polymer elastic body in addition to the high thermal conductive filler and the liquid non-volatile oil as long as the effects of the present invention are not impaired. In this case, a dispersion liquid containing non-volatile oil, a highly heat conductive filler, and a polymer elastic body is used.

  Specific examples of the polymer elastic body include, for example, polyurethane, acrylic elastic body, silicone elastic body, diene elastic body, nitrile elastic body, fluorine elastic body, polystyrene elastic body, polyolefin elastic body, and polyamide. System elastic body, halogen-based elastic body and the like. These may be used alone or in combination of two or more. Among these, polyurethane is preferable from the viewpoint of excellent wear resistance and mechanical properties.

  The polyurethane is preferably an aqueous polyurethane such as polycarbonate polyurethane, polyester polyurethane, polyether polyurethane, or polycarbonate / ether polyurethane emulsion. These polyurethanes are particularly preferable because the dispersion is easily prepared, a crosslinked structure is easily formed, and a soft texture is easily exhibited by being present in the voids without being too close to the fibers.

  Moreover, you may mix | blend components, such as surfactant, a dispersing agent, and a coloring agent, with a dispersion liquid as needed in the range which does not impair the effect of this invention.

  The method for impregnating the fiber entangled body with the dispersion is not particularly limited. Specifically, for example, a method of impregnating the fiber entangled body by dip-niping the dispersion is preferably used.

  Then, the fiber entangled body is impregnated with the dispersion liquid, and then dried to remove volatile components such as the dispersion medium in the dispersion liquid. Thereby, the highly heat conductive filler and the non-volatile oil in the dispersion remain in the gaps between the fibers of the fiber entangled body. Although drying conditions are not specifically limited, For example, the conditions of making it dry for about 1 to 10 minutes at 70-150 degreeC are mentioned. In this way, the high thermal conductive filler and the non-volatile oil are given to the gaps between the fibers of the fiber entangled body.

  Although content of the highly heat conductive filler with respect to a fiber entangled body is not specifically limited, It is preferable that it is 3-30 mass parts with respect to 100 mass parts of fiber entangled bodies, Furthermore, it is 5-20 mass parts. When the amount of the high thermal conductive filler relative to the fiber entangled body is too small, a lot of voids are likely to remain in the fiber, so that the feeling of contact cold / warmness is hardly expressed, and the sense of fulfillment tends to decrease. Moreover, when there is too much quantity of the high heat conductive filler with respect to a fiber entanglement body, there exists a tendency for a supple texture to fall.

Moreover, as content of the highly heat conductive filler with respect to 100 mass parts of fiber entangled bodies, it is preferable to contain the high heat conductive filler of the quantity equivalent to 1 mass part or more in conversion of a metal element, Furthermore, 3 mass parts or more. In the case of containing a highly heat-conductive filler corresponding to the amount containing such a metal element, it is particularly preferable from the viewpoint of excellent heat conductivity. In addition, the amount corresponding to 1 part by mass or more in terms of metal element is calculated by multiplying the mass part of the high thermal conductive filler contained by a metal element content ratio that varies depending on the type of the high thermal conductive filler. Specifically, for example, in the case of alumina (Al ₂ O ₃ ), the metal element content is 52%. In this case, 10 parts by mass of alumina is 5.2 parts by mass in terms of metal element.

  Although the compounding quantity of the non-volatile oil with respect to a fiber entangled body is not specifically limited, It is preferable that it is 2-20 mass parts with respect to 100 mass parts of fiber entangled bodies, Furthermore, it is preferable that it is 3-10 mass parts. When the amount of the non-volatile oil with respect to the fiber entangled body is too small, the texture tends to be hard. Moreover, when there is too much quantity of the non-volatile oil with respect to a fiber entanglement body, there exists a tendency for a fiber entanglement body to become unable to hold | maintain a non-volatile oil, and to take off easily.

  Moreover, the compounding quantity of the polymeric elastic body with respect to a fiber entangled body is although it does not specifically limit, 0-15 mass parts with respect to 100 mass parts of fiber entangled bodies, Furthermore, 1-14 mass parts, Especially 1-10 mass parts Part. When the amount of the polymer elastic body with respect to the fiber entangled body is too large, the rubber feeling becomes strong and the resilience becomes high, so that the supple texture tends to be lowered. Although the polymer elastic body is not an essential component, it can enhance the form stability and adjust the elasticity by blending.

  Moreover, as a ratio of the high thermal conductive filler in the total amount of the high thermal conductive filler, the non-volatile oil and the polymer elastic body, 10 to 99% by mass, further 30 to 97% by mass, particularly 50 to 90% by mass. It is preferable that When the proportion of the high thermal conductive filler is too low, the feeling of contact cold / warmness tends not to be sufficiently expressed, and the sense of fulfillment tends to decrease. Moreover, when too high, there exists a tendency for a supple texture to fall by the ratio of a non-volatile oil becoming relatively low.

  Further, the ratio of the non-volatile oil in the total amount of the high thermal conductive filler, non-volatile oil and polymer elastic body is not particularly limited, but is 1 to 90% by mass, more preferably 3 to 70% by mass, and particularly 10 to 10%. 50% by mass, particularly 20 to 35% by mass, is preferable from the viewpoint of obtaining a supple texture and a sense of fulfillment. When the proportion of the non-volatile oil is too low, the supple texture tends to decrease, and when it is too high, the proportion of the high heat conductive filler is relatively low, so that the feeling of contact cold / warmness is not sufficiently expressed. At the same time, the sense of fulfillment tends to decrease.

The proportion of the polymer elastic body in the total amount of the high thermal conductive filler, the nonvolatile oil and the polymer elastic body is preferably 0 to 40% by mass, and more preferably 1 to 20% by mass. When the proportion of the polymer elastic body is too high, the q-max value tends to be less than 0.25 W / cm ² or more and tends to have a rubber-like texture.

  In this way, an artificial leather base material is obtained in which the voids between the fibers of the fiber entangled body are impregnated with a high thermal conductive filler, a non-volatile oil and, if necessary, a polymer elastic body. Such artificial leather base materials are subjected to thickness adjustment and flattening treatment by slicing or buffing treatment as necessary, stagnation softening treatment, blanking softening treatment, reverse seal brushing treatment, antifouling treatment Finishing treatment such as treatment, hydrophilization treatment, lubricant treatment, softener treatment, antioxidant treatment, ultraviolet absorber treatment, fluorescent agent treatment, flame retardant treatment and the like may be performed.

  For the purpose of adjusting the sense of fulfillment and flexibility of the artificial leather base material, it is preferable to flexibly process the artificial leather base material impregnated with a high thermal conductive filler, a non-volatile oil and, if necessary, a polymer elastic body. The method of softening is not particularly limited, but there is a method in which an artificial leather base material is brought into close contact with an elastic sheet and mechanically contracted in the vertical direction (MD of the production line), and heat-set by heat treatment in the contracted state. preferable. By adopting this method, it is possible to make it flexible while improving the smoothness of the surface.

Artificial leather substrate of the present embodiment, the contact cold feeling at least one surface, is as a maximum heat absorption rate (q-max value) 0.25 W / cm ² or more, preferably 0.28 W / cm ² or more, further Preferably it is 0.3 W / cm ² or more. Thus, when the maximum heat absorption rate (q-max value) is 0.25 W / cm ² or more, the heat transfer efficiency is increased, and for example, a cooling sensation can be obtained when contacting the skin. The feeling of coldness in contact is the skin sensation related to the temperature that is felt when a person touches an object, such as cold or warm, and the maximum heat absorption rate that changes depending on the amount of heat transferred from the skin to the object. It is evaluated by (q-max value). The larger the q-max value, the faster the heat conduction, and the greater the feeling of cooling when touched by a person.

Moreover, the artificial leather base material of this embodiment has a heat retention rate of 30% or less measured according to the heat retention “Method A” of JIS L1096 on the surface having the q-max value of 0.25 W / cm ² or more. Further, it is preferably 25% or less, particularly 20% or less. The heat retention rate is an index for retaining the absorbed heat, and the heat is more easily released as the heat retention rate is lower. That is, the lower the heat retention rate of the artificial leather base material, the faster the absorbed heat is released, and thus the better the feeling of cooling.

The thickness of the artificial leather base material is not particularly limited, but is preferably about 100 to 3000 μm, more preferably about 300 to 2000 μm. Further, the apparent density of the artificial leather base material is not particularly limited, but it is 0.55 to 0.85 g / cm ³ , and more preferably 0.60 to 0.80 g / cm ³ From the viewpoint of excellent balance.

  The artificial leather base material is finished into artificial leather by applying a treatment for imparting a desired appearance to the surface. Artificial leather includes, for example, raised artificial leather (suede, nubuck, velor, buckskin) that has a buffed appearance by buffing the surface of the artificial leather base material to raise or raise the fibers, Examples thereof include a silver-tone artificial leather having a leather-like resin layer provided on the surface of a leather substrate.

  Brushed artificial leather (suede, nubuck, velor, buckskin) can be obtained by buffing the surface layer of an artificial leather base material with sandpaper or the like and raising or raising the surface.

  The silver-tone artificial leather can be obtained by forming a silver-tone resin layer on the surface of the artificial leather substrate. The method for forming a silver-tone resin layer on the surface of the artificial leather substrate is not particularly limited, and for example, a dry surface forming method or a direct coating method is used. In the dry surface-forming method, a coating liquid containing a colored resin for forming a silver surface layer is applied on a release sheet, and then a film is formed by drying, and the film is adhered to the surface of the artificial leather substrate. This is a method of peeling the release sheet after pasting together. The direct coating method is a method in which a coating liquid containing a resin is applied directly to the surface of an artificial leather substrate by a roll coater or a spray coater and then dried.

The artificial leather of the present embodiment has both flexibility as natural leather and a high sense of fulfillment. Specifically, for example, it is preferable that the softness measured by a soft tester is 2.0 mm or more, preferably 2.5 to 4.0 mm. The apparent density is preferably 0.55 to 0.85 g / cm ³ , and more preferably 0.60 to 0.80 g / cm ³ .

  In addition, it is possible to soften stagnation, soften by punching, brushing reverse seal, antifouling, hydrophilization, lubricant, softener, antioxidant, UV absorber, fluorescent agent, flame retardant. A finishing process such as a process may be performed.

  The artificial leather thus formed can be used as a skin material for various products as a sheet or as a three-dimensionally molded article formed by hot pressing. Specifically, for example, skins for leather products such as shoes and bags, interior materials such as seats for automobiles, skins used integrally with the surface of mobile phones, mobile devices, home appliances, etc. Used as a material.

  A three-dimensionally molded article can be obtained, for example, by hot press molding artificial leather using a mold having a three-dimensional cavity composed of a male mold and a female mold. When heat-pressing artificial leather including the artificial leather base material according to the present invention, the artificial leather base material is excellent in thermal conductivity. Further, the fiber entangled body contained in the artificial leather base material is hardly fused. Therefore, the molded product obtained after hot pressing does not become hard, and a soft texture is easily maintained.

  The present invention will be described more specifically with reference to examples. The scope of the present invention is not limited by the examples.

[Example 1]
<Manufacture of non-woven fabric>
Water-soluble thermoplastic polyvinyl alcohol (PVA) as the sea component, isophthalic acid-modified polyethylene terephthalate having a modification degree of 6 mol% as the island component, and a uniform cross-sectional area in the sea component set at a base temperature of 260 ° C. Molten resin was supplied to a plurality of spinning nozzles in which nozzle holes forming a cross section in which 25 island components were distributed were arranged in parallel, and were discharged from the nozzle holes. At this time, it supplied, adjusting pressure so that the mass ratio of a sea component and an island component might become sea component / island component = 25/75.

Then, the discharged melted fiber was drawn by a suction device so that the average spinning speed was 3700 m / min, and a long fiber of a sea-island type composite fiber having a fineness of 2.1 dtex was spun. The spun long islands of sea-island type composite fibers were continuously deposited on a movable net, and lightly pressed with a metal roll at 42 ° C. to suppress surface fuzz. And the long fiber of the sea-island type composite fiber was peeled off from the net, and passed between a lattice-shaped metal roll having a surface temperature of 55 ° C. and a back roll. In this manner, a hot fiber web having a basis weight of 31 g / m ² was obtained by hot pressing at a linear pressure of 200 N / mm.

Next, the web was overlapped on 8 layers using a cross-wrapper apparatus so that the total basis weight was 250 g / m ² , an overlapped web was prepared, and a needle breakage preventing oil was sprayed. Next, using a 6 barb needle with a distance of 3.2 mm from the tip of the needle to the first barb, needle punching was alternately performed at 3300 punch / cm ² from both sides at a needle depth of 8.3 mm. The area shrinkage rate by the needle punching process was 68%, and the basis weight of the entangled web after the needle punching was 550 g / m ² .

The entangled web was immersed in hot water at 70 ° C. for 14 seconds at a winding line speed of 10 m / min to cause area shrinkage. Next, by repeatedly performing dip nip treatment in hot water at 95 ° C. to dissolve and remove PVA, a fiber bundle having a fineness of 2.5 dtex containing 25 ultrafine fibers having a fineness of 0.1 dtex was entangled three-dimensionally. A nonwoven fabric was prepared. The area shrinkage percentage measured after drying was 52%. The nonwoven fabric was sliced and buffed to adjust the thickness to 1.05 mm. The nonwoven fabric of ultrafine fibers, which is the fiber entanglement thus obtained, had a basis weight of 576 g / m ² and an apparent density of 0.565 g / cm ³ .

<Impregnation with high heat conductive filler and liquid non-volatile oil>
An aqueous dispersion containing 35% owf of alumina particles, 15% owf of non-volatile oil (liquid paraffin), and 5% owf of an aqueous polyurethane was prepared. Then, after impregnating the dispersion into the non-woven fabric of ultrafine fibers at a pickup rate of 85%, the moisture was dried to impregnate with alumina, liquid paraffin, and aqueous polyurethane. Then, a non-woven fabric of ultrafine fibers impregnated with alumina, liquid paraffin, and water-based polyurethane was contracted using a contraction processing device (manufactured by Komatsubara Tekko Co., Ltd., Sun Foraging Machine). This was treated at a drum temperature of 120 ° C. at a conveyance speed of 10 m / min and contracted 4.0% in the vertical direction (length direction) to obtain an artificial leather base material. The obtained artificial leather base material contains 10.5 parts by mass of alumina, 4.5 parts by mass of liquid paraffin, and 1.5 parts by mass of water-based polyurethane with respect to 100 parts by mass of the nonwoven fabric of ultrafine fibers, and has a basis weight of 680 g / m. ² and the apparent density was 0.671 g / cm ³ .

  As the alumina particles, an aqueous dispersion (KTC-18 manufactured by Daikyo Chemical Co., Ltd., solid content 40%) of alumina particles having an average particle diameter of 5 μm (thermal conductivity 30 W / mK) was used. In addition, the metal element content rate of an alumina is 52 mass%. As liquid paraffin, an aqueous dispersion of liquid paraffin (Lastex LB manufactured by Daikyo Chemical Co., Ltd., solid content 30%) was used. Further, as the water-based polyurethane, the soft segment is a 70:30 mixture of polyhexylene carbonate diol and polymethylpentanediol, and the hard segment is a crosslinked type polyurethane mainly composed of hydrogenated methylene diisocyanate (solid content 30% by mass, An emulsion having a melting point of 180 to 190 ° C., a loss elastic modulus peak temperature of −15 ° C., and a hot water swelling ratio at 130 ° C. of 35% was used.

<Formation of silver layer: Tanner treatment>
A base coat layer having a thickness of 28 μm was formed on the surface of the artificial leather base material by roll-coating the base coat solution at a coating amount of 140 g / m ² using STARPLUS manufactured by Gemata. In addition, as the base coat solution, a polyurethane emulsion (DIC Co., Ltd., LCC binder UB1770 solid content 30% by mass) adjusted with a thickener so that the viscosity of Ford Cup No. 4 55S was 195 mPa · s was used. . Then, a color coat layer having a film thickness of 14 μm was formed by spray coating the surface of the formed base coat layer with a color coat solution at a coating amount of 70 g / m ² using STARPLUS manufactured by Gemata. As the color coating solution, a polyurethane emulsion (DIC Co., Ltd., LCC binder UB1770 solid content 30%) adjusted with an Iwata cup (IWATA NK-2 12s) to 30 mPa · s was used. Further, the blanking process was performed at 40 to 50 ° C. for 2 to 4 hours. Then, the surface layer was embossed using an embossing roll at 125 ° C. and 50 kg / cm ² at a line speed of 7.0 m / min. Then, a top coat paint (clear paint made by Tope Co., Ltd.) adjusted to 30 mPa · s with an Iwata cup (IWATA NK-2 12s) was applied to the surface to form a top coat with a film thickness of 13.5 μm. In this way, a silver-tone artificial leather having a basis weight of 745.5 g / m ² and an apparent density of 0.697 g / cm ³ was obtained.

<Evaluation of artificial leather>
The obtained artificial leather was evaluated according to the following evaluation methods.

(Measurement of maximum heat absorption rate (q-max value))
As an evaluation of the contact cooling sensation, the maximum heat absorption rate (q-max value) was measured using a precise rapid thermophysical property measuring apparatus (KES-F-M7 Thermolab II type, Kato Tech Co., Ltd.). In the measurement, the surface on which the silver surface layer of the artificial leather is not formed is used as the measurement surface, and the temperature difference between the temperature detector and the measurement surface of the artificial leather is 20 ° C. in a room with a room temperature of 20 ° C. and a humidity of 65% RH. Measured with setting. In addition, the q-max value of the surface where the silver surface layer of the artificial leather is not formed is substantially equal to the q-max value of the surface of the artificial leather base material where the silver surface layer is not formed.

(Measurement of thermal insulation rate according to JIS L1096 thermal insulation "Method A")
A test piece was attached to a constant temperature heating element set to a constant temperature (36 ± 0.5 ° C.) using a heat retention tester, and the amount of heat (a) dissipated through the test piece after 2 hours was determined. On the other hand, the amount of heat (b) dissipated after 2 hours in a state where no test piece was attached was determined. And the heat retention rate (%) was calculated by the following formula: heat retention rate (%) = (1−a / b) × 100.

(Sensory evaluation of cold feeling of contact)
The surface of the artificial leather that was left in a room at room temperature of 20 ° C. and a humidity of 65% RH for 24 hours was touched with each palm with 10 general consumers as subjects. Then, the cold feeling of contact felt by each subject was determined according to the following criteria.
A: A clear feeling of cooling was given B: A feeling of cooling was not obtained or was not obtained clearly

(Bending softness: softness)
Bending softness was measured using a softness tester (leather softness measuring device ST300: manufactured by MSA Engineering System, UK). Specifically, a predetermined ring having a diameter of 25 mm was set in the lower holder of the apparatus, and then a silver-tone artificial leather was set in the lower holder. And the metal pin (diameter 5 mm) fixed to the upper lever was pushed down toward the silver-finished artificial leather. And the numerical value when the upper lever was pushed down and the upper lever was locked was read. The numerical value represents the penetration depth, and the larger the numerical value, the more flexible.

(Texture)
A sample was prepared by cutting out artificial leather into 20 × 20 cm. Then, the appearance when bent inward from the center and the appearance when gripped were determined according to the following criteria.
A: When it was bent, it was bent like a round, and fine and fine creases were generated. It was also excellent in drape.
B: When bent, it bent and bent, and rough wrinkles and deep wrinkles were generated. Moreover, it was inferior to the drape property.
C: The texture was remarkably low.
(Apparent density)
According to JIS L1913, the thickness (mm) and the basis weight (g / cm ² ) were measured, and the apparent density (g / cm ³ ) was calculated from these values.

  The above evaluation results are shown in Table 1 below.

[Examples 2-3]
In Example 1, artificial leather was obtained and evaluated in the same manner as in Example 1 except that the number of blended parts of each component relative to the nonwoven fabric of ultrafine fibers was changed as shown in Table 1. The results are shown in Table 1.

[Example 4]
In Example 1, artificial leather was prepared in the same manner as in Example 1 except that titanium oxide particles having an average particle size of 5 μm (thermal conductivity 21.9 W / mK) were used instead of mixing alumina particles having an average particle size of 5 μm. Obtained and evaluated. In addition, the metal element content rate of titanium oxide is 57.9 mass%. The results are shown in Table 1.

[Example 5]
In the composition of the dispersion prepared in Example 1, instead of blending alumina particles having an average particle size of 5 μm, an aluminum dialkylphosphinate having an average particle size of 5 μm (composition formula C ₁₂ H ₃₀ AlO ₆ P ₃ ) (thermal conductivity 10 W / mK) was added and evaluated in the same manner as in Example 1 except that silver-finished artificial leather was obtained. In addition, the metal element content rate of aluminum dialkylphosphinate is 20 mass%. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, artificial leather was obtained and evaluated in the same manner as in Example 1 except that 10.5 parts by mass of alumina particles was added to 100 parts by mass of the nonwoven fabric, instead of 1 part by mass of alumina particles. The results are shown in Table 1.

[Comparative Example 2]
In Example 1, instead of impregnating a dispersion containing alumina, liquid paraffin, and water-based polyurethane into the nonwoven fabric of ultrafine fibers, 12.5 parts by mass of solid content is contained with respect to 100 parts by mass of the nonwoven fabric of ultrafine fibers. Thus, artificial leather was obtained and evaluated in the same manner except that the same aqueous polyurethane dispersion used in Example 1 was impregnated and dried at 120 ° C. The obtained artificial leather base material contained 12.5 parts by mass of an aqueous polyurethane with respect to 100 parts by mass of the nonwoven fabric of ultrafine fibers. The results are shown in Table 1.

[Comparative Example 3]
In Example 1, instead of impregnating and adding a dispersion containing alumina, liquid paraffin, and water-based polyurethane to the nonwoven fabric of ultrafine fibers, 30 parts by mass of solid content is contained with respect to 100 parts by mass of the nonwoven fabric of ultrafine fibers. Artificial leather was obtained and evaluated in the same manner except that it was impregnated with the same aqueous polyurethane dispersion used in Example 1 and dried at 120 ° C. The obtained artificial leather base material contained 30 parts by mass of water-based polyurethane with respect to 100 parts by mass of the nonwoven fabric of ultrafine fibers. The results are shown in Table 1.

[Comparative Example 4]
In Example 1, instead of an artificial leather base material, general natural leather (genuine leather) whose tissue was highly filled with collagen fibers was evaluated. The results are shown in Table 1.

In any of the artificial leather substrates obtained in Examples 1 to 5 according to the present invention, the q-max value is 0.25 W / cm ² or more, the heat retention is 25% or less, and the sensory evaluation of the feeling of contact cooling Each subject got a clear cool feeling. Moreover, it was an artificial leather having an apparent density of 0.6 g / cm ³ or more, a softness of 2.0 mm or more, and having both a sense of fulfillment and flexibility.

Moreover, the artificial leather of Comparative Example 1 obtained by blending 1 part by mass of alumina particles with respect to 100 parts by mass of the ultrafine nonwoven fabric has a q-max value of 0.213 W / cm ² and a heat retention rate. It was 25.5%, and in the sensory evaluation of the contact cooling sensation, each subject did not obtain a clear cooling sensation.

Moreover, the artificial leather of Comparative Example 2 obtained by blending only 12.5 parts by mass of water-based polyurethane with 100 parts by mass of non-woven fabric of ultrafine fibers has a q-max value of 0.225 W / cm ² and is kept warm. The rate was 25.8%, and in the sensory evaluation of the cool contact feeling, each subject did not obtain a clear cool feeling.

Further, the artificial leather of Comparative Example 3 obtained by blending only 30 parts by mass of water-based polyurethane with 100 parts by mass of the nonwoven fabric of ultrafine fibers has a q-max value of 0.233 W / cm ² and a heat retention rate of 30. 9%, and in the sensory evaluation of the contact cooling sensation, each subject did not obtain a clear cooling sensation.

In Comparative Example 4, as a result of evaluating a general natural leather (genuine leather) in which the tissue was densely filled with collagen fibers, the q-max value was 0.291 W / cm ² , and the heat retention rate was 21. It was 1%, and each subject obtained a clear cooling feeling in the sensory evaluation of the contact cooling feeling.

From the above examples, the fiber entangled body, a high thermal conductivity filler with a thermal conductivity of 1 W / mK or more, and a liquid non-volatile oil impregnated in the fiber entangled body, and a liquid non-volatile oil have a q-max value of 0. According to the artificial leather substrate having a surface of 25 W / cm ² or more, the high thermal conductive filler impregnated in the gaps between the fibers of the fiber entangled body quickly takes away the heat of the skin and gives a cool feeling to the person. Further, the high thermal conductive filler and the liquid non-volatile oil impart a texture and a feeling of fullness to the artificial leather.

[Example 6 and Comparative Example 5]
The artificial leather obtained in each of Example 1 and Comparative Example 2 was hot-pressed with a soap box-shaped mold having a surface temperature of 175 ° C. for 10 seconds to obtain a molded body having a three-dimensional shape. . As a result, the molded product obtained by molding the artificial leather of Example 1 having excellent thermal conductivity maintained a supple or flexible texture. On the other hand, the molded product obtained by molding the artificial leather of Comparative Example 3 melts so that the fiber component and the polymer elastic body are crushed by the heat applied during the hot pressing. It turned into a worn state and lost its supple or flexible texture and had a hard texture.

  The artificial leather using the artificial leather base material of the present invention is used as a leather-like material for shoes, clothing, gloves, bags, balls, interiors, vehicle interiors, and the like.

Claims (9)

A fiber entangled body, a high thermal conductive filler impregnated in the fiber entangled body and having a thermal conductivity of 1 W / mK or more and a liquid nonvolatile oil,
An artificial leather substrate characterized in that the cold feeling of contact on at least one surface is 0.25 W / cm ² or more as a maximum heat absorption rate (q-max value). The artificial leather base material according to claim 1, wherein a heat retention rate measured according to JISL1096 heat retention "Method A" is 25% or less on a surface having the q-max value of 0.25 W / cm ² or more.   The artificial leather base material of Claim 1 or 2 which contains 3-30 mass parts of said highly heat conductive fillers with respect to 100 mass parts of said fiber entangled bodies.   The artificial leather base material of any one of Claims 1-3 which contains the said highly heat conductive filler of the quantity equivalent to 1 mass part or more in conversion of a metal element with respect to 100 mass parts of said fiber entangled bodies.   The artificial leather base material according to any one of claims 1 to 4, wherein the nonvolatile oil includes at least one selected from liquid paraffin, silicone oil, mineral oil, and phthalates. The artificial leather substrate according to any one of claims 1 to 5, which has an apparent density of 0.55 g / cm ³ or more.   The artificial leather base material according to any one of claims 1 to 6, wherein the fiber entangled body includes a nonwoven fabric of ultrafine fibers having a fineness of 0.9 dtex or less.   The artificial leather containing the artificial leather base material of any one of Claims 1-7.   A leather-like molded product obtained by imparting a three-dimensional shape to the artificial leather according to claim 8 by hot pressing.