JP7635991B2 - Interior covering material and method for producing same - Google Patents

Description

The present invention relates to an interior covering material that uses nonwoven fabric as a base material.

Conventionally, floor carpets that use nonwoven fabric as the interior covering material and have a foamed resin layer on the back side have been known (for example, Patent Documents 1 and 2).

JP 2000-177056 A JP 2004-027466 A

A floor carpet having a foamed resin layer on the back side of an interior covering material is formed by heating a nonwoven fabric as an interior covering material and a foamable resin filled on the back side of the nonwoven fabric in a molding die, causing the foamable resin to foam. However, to ensure sound absorption, the interior covering material is required to have air permeability. For this reason, conventional interior covering materials have an issue in that when the foamable resin is filled in the molding die and then heated, the foamable resin may penetrate the nonwoven fabric and reach the surface side.

The problem that the technology of this specification aims to solve was made in consideration of the above-mentioned points, and aims to provide an interior covering material with a nonwoven fabric base material that can suppress the penetration of foamable resin.

The interior covering material according to the embodiment of the present specification comprises a covering substrate made of a needle-punched nonwoven fabric which is formed from synthetic resin fibers having a thickness of 0.5 to 20 dtex and has a basis weight of 100 to 300 g/ ^m2 and is needle-punched;
a synthetic resin porous layer provided under the skin substrate and having a coating amount of 20 to 100 g/ ^m2 calculated as non-volatile content;
The present invention is characterized by having the following.

The interior skin material according to the embodiment of the present specification comprises a skin substrate made of a needle-punched nonwoven fabric which is needle-punched to form a web having a basis weight of 100 to 300 g/m ² and which is made of synthetic resin fibers having a thickness of 0.5 to 20 dtex, and a synthetic resin porous layer having a non-volatile content of 20 to 100 g/m ² provided below the needle-punched nonwoven fabric. As a result, the interior skin material according to the embodiment has a synthetic resin porous layer formed so as to fill the gaps in the nonwoven fabric, and therefore can suppress the penetration of the foamable resin when the foamable resin is filled into the back side of the fabric in a molding die and then heated.

Here, in the above-mentioned interior skin material, the synthetic resin porous layer may be impregnated into the skin base material.

As a result, since the synthetic resin porous layer is impregnated into the skin substrate, when the foamable resin is filled on the back side of the skin substrate in the molding die and then heated, the interior skin material can suppress the penetration of the foamable resin.

In addition, in the above-mentioned interior skin material, the synthetic resin porous layer may be formed in a foam rubber shape.

With this, a foam rubber-like synthetic resin porous layer is formed on the underside of the skin substrate, so when the foamable resin is filled on the back side of the skin substrate in the molding die and then heated, the interior skin material can suppress the penetration of the foamable resin.

In addition, in the above-mentioned interior skin material, the skin substrate may include a permeation-preventing nonwoven fabric on the underside of the needle-punched nonwoven fabric, and the needle-punched nonwoven fabric and the permeation-preventing nonwoven fabric may be needle-punched together.

This allows the penetration of the foamable resin filled on the back side of the skin substrate to be suppressed by the penetration-preventing nonwoven fabric.

In addition, in the above-mentioned interior covering material, the permeation-preventing nonwoven fabric may be a spunbond nonwoven fabric, a meltblown nonwoven fabric, or a wet-laid nonwoven fabric.

This allows the interior skin material to effectively suppress the penetration of the foamable resin.

In addition, in the above-mentioned interior skin material, the synthetic resin forming the synthetic resin porous layer may be an acrylic resin.

This allows the interior covering material to have excellent durability.

In addition, in the above-mentioned interior skin material, thermally expandable capsules may be mixed into the synthetic resin porous layer.

This allows the amount of air permeability of the interior covering material to be reduced.

Here, the interior skin material according to the embodiment is an interior skin material in which an upper-layer skin substrate and a lower-layer skin substrate are needle-punched,
the upper-layer skin substrate is a nonwoven fabric formed by needle punching a web made of synthetic resin fibers having a thickness of 0.5 to 20 dtex and having a basis weight of 50 to 200 g/ ^m2 ;
The lower skin substrate is characterized in that it is made of synthetic resin fibers having a thickness of 0.5 to 20 dtex, and the web having a basis weight of 50 to 200 g/m ² is a needle-punched nonwoven fabric.

According to this, the interior skin material according to the embodiment is needle-punched from an upper-layer skin substrate formed from synthetic resin fibers having a thickness of 0.5 to 20 dtex and a web having a basis weight of 50 to 200 g/m ² , and a lower-layer skin substrate formed from synthetic resin fibers having a thickness of 0.5 to 20 dtex and a web having a basis weight of 50 to 200 g/m ^2. Because the two layers of needle-punched nonwoven fabric are needle-punched, the interior skin material according to the embodiment is able to suppress penetration of the foamable resin when it is filled with the foamable resin and then heated, by the two layers of needle-punched nonwoven fabric.

In addition, in the above-mentioned interior skin material, an intermediate film layer may be interposed between the upper skin substrate and the lower skin substrate.

This allows the intermediate film layer to suppress the penetration of the foamable resin.

The interior skin material of this embodiment can suppress the penetration of the foamable resin when it is filled on the back side of the mold and then heated.

1 is a cross-sectional image of an interior covering material according to a first embodiment; FIG. 6 is a cross-sectional image of an interior covering material according to a second embodiment. 11 is an enlarged photograph of the rear surface of the interior covering material of Example 3 (first embodiment). 11 is an enlarged photograph of the rear surface of the interior covering material of Example 4 (first embodiment). 1 is a graph showing the normal incidence sound absorption coefficient of floor carpets using the interior covering materials of Examples 3 and 4.

First Embodiment
Hereinafter, the interior covering material 101 according to the first embodiment of the present specification will be described with reference to the drawings. The scope of the present invention is not limited to the scope disclosed in the embodiment. The interior covering material 101 according to the first embodiment is heated together with the foamable resin filled on its back side in a mold, and the foamable resin is foamed to provide a foamed resin layer F on the back side, thereby forming a floor carpet for an automobile interior material. As shown in FIG. 1, the interior covering material 101 according to the first embodiment has a skin substrate 10 having a needle-punched nonwoven fabric 5 as a base material, and a synthetic resin porous layer 60 having a coating amount of 20 to 100 g/m ² in terms of non-volatile content, which is provided on the underside of the skin substrate 10. As a result, the interior covering material 101 according to the first embodiment can suppress the penetration of the foamable resin when the foamable resin is filled on its back side in a mold and then heated, even without using an oil repellent.

The needle-punched nonwoven fabric 5, which is the base material of the skin substrate 10, is made by needle-punching a web made of synthetic resin fibers 1. The synthetic resin fibers 1 can be fully melted synthetic resin fibers 1 made of a single resin composition, or core-sheath type synthetic resin fibers 1, which are composite fibers with a core-sheath structure in which a high-melting-point resin core and a low-melting-point resin sheath. Note that multiple types of these synthetic resin fibers 1 can also be used in combination.

In an embodiment, the fully fused synthetic resin fiber 1 made of a single resin can be polyester fiber, polyolefin fiber (PE (polyethylene), PP (polypropylene), etc.), PA (polyamide) fiber, acrylic resin fiber, polyvinyl alcohol fiber, etc. In another embodiment, the fully fused synthetic resin fiber 1 can be polyester fiber with excellent strength and water resistance, and in yet another embodiment, PET (polyethylene terephthalate) fiber, which is a polyester fiber, can be used.

In an embodiment, the sheath-core type synthetic resin fiber 1 made of a core-sheath composite fiber can be expressed as PET/low melting point PET, PET/PE, PET/PP, PET/PA, PP/PE, PA/PA, etc., in terms of core/sheath. In another embodiment, the sheath-core type synthetic resin fiber 1 can be made of PET/low melting point PET, PET/PE, or PET/PP, which have excellent strength, and in yet another embodiment, PET/low melting point PET can be used.

In the embodiment, the thickness of the synthetic resin fiber 1 can be 0.5 to 20 dtex in terms of the fineness (dtex) which is the weight of 10,000 m of fiber. This is because the needle-punched nonwoven fabric 5 formed from the synthetic resin fiber 1 can be easily formed, and the interior skin material 101 can suppress the penetration of the foamable resin when the interior skin material 101 is formed and the back side of the interior skin material 101 is filled with the foamable resin in the molding die and then heated. If the fineness of the synthetic resin fiber 1 is less than 0.5 dtex, the production efficiency may be poor because the synthetic resin fiber 1 is thin. On the other hand, if the fineness of the synthetic resin fiber 1 exceeds 20 dtex, the synthetic resin fiber 1 is thick, and therefore, there is a risk that the interior skin material 101 cannot suppress the penetration of the foamable resin when the interior skin material 101 is formed and filled with the foamable resin and then heated. In another embodiment, the fineness of the synthetic resin fiber 1 can be 1 to 10 dtex, and in yet another embodiment, the fineness of the synthetic resin fiber 1 can be 2 to 5 dtex.

In an embodiment, the length of the synthetic resin fiber 1 can be 20 to 100 mm. This is because the needle-punched nonwoven fabric 5 can be easily formed. If the length of the synthetic resin fiber 1 is less than 20 mm, it may be impossible to form the needle-punched nonwoven fabric 5 because it is too short. On the other hand, if the length of the synthetic resin fiber 1 exceeds 100 mm, it may be difficult to form the needle-punched nonwoven fabric 5 because it is too long. In another embodiment, the length of the synthetic resin fiber 1 can be 25 to 90 mm, and in yet another embodiment, it can be 30 to 80 mm.

In the embodiment, the basis weight of the web (basis weight of the needle-punched nonwoven fabric 5) can be 100 to 300 g/m ^2. This is because when the interior skin material 101 is formed from the needle-punched nonwoven fabric 5 and the foamable resin is filled on the back side of the interior skin material 101 in the mold and then heated, the interior skin material 101 can suppress the penetration of the foamable resin. If the basis weight of the needle-punched nonwoven fabric 5 is less than 100 g/m ² , the interior skin material 101 may not be able to suppress the penetration of the foamable resin when the interior skin material 101 is formed from the needle-punched nonwoven fabric 5 and the foamable resin is filled and then heated. On the other hand, if the basis weight of the needle-punched nonwoven fabric 5 exceeds 300 g/m ² , the penetration of the foamable resin can be suppressed, but the amount is excessive, which may be uneconomical. In another embodiment, the weight per unit area of the needle-punched nonwoven fabric 5 can be 180 to 290 g/m ² , and in yet another embodiment, 220 to 280 g/m ² .

The skin substrate 10 used in the interior skin material 101 of the embodiment can be provided with a permeation-preventing nonwoven fabric 20 on the underside of the needle-punched nonwoven fabric 5, and the needle-punched nonwoven fabric 5 and the permeation-preventing nonwoven fabric 20 can be needle-punched. This is because the permeation-preventing nonwoven fabric 20 allows the interior skin material 101 to further suppress the permeation of the foamable resin when the foamable resin is filled on the back side of the interior skin material 101 in the molding die and then heated. As the permeation-preventing nonwoven fabric 20, a nonwoven fabric such as a spunbond nonwoven fabric, a melt-blown nonwoven fabric, or a wet-laid nonwoven fabric can be used. In another embodiment, the permeation-preventing nonwoven fabric 20 can be a spunbond nonwoven fabric.

The interior skin material 101 of the embodiment has a synthetic resin porous layer 60 on the underside of the skin substrate 10. The synthetic resin porous layer 60 is formed from a synthetic resin emulsion, and either an impregnation layer 61 or a foam rubber layer 62 is formed depending on the application method. The impregnation layer 61 is formed as the synthetic resin porous layer 60 in which the synthetic resin emulsion is impregnated or semi-impregnated into the interior skin material 101 by applying the synthetic resin emulsion to the back surface of the skin substrate 10 using a doctor knife. The foam rubber layer 62 is formed as the synthetic resin porous layer 60 by applying a foamed synthetic resin emulsion to the back surface of the skin substrate 10. The synthetic resin porous layer 60 is formed as either the impregnation layer 61 or the foam rubber layer 62, but when the foam rubber layer 62 is formed, it has an impregnation layer in which part of the synthetic resin emulsion is impregnated into the skin substrate 10.

The amount of synthetic resin emulsion applied to form the synthetic resin porous layer 60 can be 20 to 100 g/m ² in terms of non-volatile content, whether it is the impregnated layer 61 or the foam rubber layer 62. This is because the penetration of the foamable resin can be suppressed and the interior skin material 101 can be given a suitable rigidity. If the amount of synthetic resin emulsion applied (hereinafter, the amount of application is in terms of non-volatile content) is less than 20 g/m ² , there is a risk that the penetration of the foamable resin cannot be suppressed and the interior skin material 101 cannot be given a suitable rigidity. On the other hand, if the amount of synthetic resin emulsion applied exceeds 100 g/m ² , it may be an excessive amount and may be uneconomical. In another embodiment, the amount of synthetic resin emulsion applied can be 30 to 80 g/m ² , and in yet another embodiment, it can be 40 to 60 g/m ² .

The synthetic resin emulsion may be made of acrylic resin, vinyl acetate resin, vinyl versatate resin, ethylene vinyl acetate copolymer resin, styrene butadiene resin, or the like. In another embodiment, an acrylic resin emulsion with excellent weather resistance may be used.

In other words, an acrylic resin emulsion is a copolymer emulsion containing modified acrylic ester. As structural units that become copolymers of acrylic ester, (meth)acrylic acid, di(meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 2-aminoethyl (meth)acrylate, (meth)acrylamide, N-methylol (meth)acrylamide, N-(2-hydroxyethyl) (meth)acrylamide, (meth)acrylonitrile, and mixtures thereof, as well as mixtures of these with styrene, can be used. As resins to be modified, urethane-modified, silicone-modified, vinyl chloride-modified, etc. can be used. Of course, unmodified acrylic ester copolymer emulsions can also be used. As another embodiment, an acrylic resin emulsion containing acrylonitrile can be used as a structural unit that becomes a copolymer of acrylic ester. In yet another embodiment, an acrylic resin emulsion containing acrylonitrile and styrene as structural units that form an acrylic acid ester copolymer can be used. For example, a mixture of an acrylonitrile-styrene-acrylic acid ester copolymer emulsion or an acrylonitrile-acrylic acid ester copolymer emulsion can be used.

The acrylic resin (modified acrylic acid ester copolymer) constituting the acrylic resin emulsion can have a glass transition temperature (Tg) of 0 to 50°C. This is because it can impart an appropriate rigidity to the interior skin material 101. If the Tg of the acrylic resin is less than 0°C, the resin is soft and may not be able to impart an appropriate rigidity to the interior skin material 101. On the other hand, if the Tg of the acrylic resin exceeds 50°C, the film formation temperature (≒Tg) is high and it may be difficult to form a film of the acrylic resin. In another embodiment, the glass transition temperature (Tg) of the resin can be 5 to 30°C, and in yet another embodiment, 10 to 20°C.

The Tg of the acrylic resin can be adjusted by adjusting the type and amount of the monomer (structural unit that becomes a copolymer of acrylic acid ester) used. Tg can be calculated from the FOX formula (formula (1) below). Wi indicates the mass fraction of monomer i, Tgi indicates the Tg (°C) of monomer i, and the Tg of the monomer can be a known value such as the value described in the Polymer Handbook (John Willey & Sons).

1/(273+Tg)=Σ(Wi/(273+Tgi))...(1)

The acrylic resin emulsion can be prepared by adding a pre-emulsion (a monomer component, a surfactant, water, etc. pre-emulsified) and a polymerization initiator dropwise over a period of about 2 hours into a reactor in which a polymerization reaction proceeds, in which an aqueous solution containing a surfactant and the like is placed, and the aqueous solution is adjusted to 80 to 90° C. A synthetic resin emulsion can be prepared by polymerizing the monomer component. It should be noted that an emulsion having a core-shell structure can be prepared by preparing two or more types of pre-emulsion and dropping them in sequence.

The synthetic resin porous layer 60 (impregnated layer 61, foam rubber layer 62) can be mixed with thermally expandable capsules 70. By mixing the thermally expandable capsules 70 into the synthetic resin porous layer 60, the interior skin material 101 can suppress the amount of air permeability (woven and knitted fabric test method (JIS L 1096:2010) 8.26 Air Permeability A Method (Fragile type method)), and when the foamable resin is filled on the back side of the interior skin material 101 in the molding die and then heated, the penetration of the foamable resin into the interior skin material 101 can be suppressed and appropriate rigidity can be imparted to the interior skin material 101. The thermally expandable capsules 70 have a particle diameter of 10 to 50 μm before expansion, but expand to a particle diameter of 30 to 200 μm when heated. In another embodiment, the thermally expandable capsule 70 can have a particle size of 15 to 40 μm before expansion, and expand to a particle size of 50 to 180 μm when heated.

In an embodiment, the thermally expandable capsule 70 may be a commercially available product, and examples of commercially available products that may be used include Kureha Microsphere (manufactured by Kureha Corporation), Advancel EM (manufactured by Sekisui Chemical Co., Ltd.), and Expancel (manufactured by Nippon Ferrite Co., Ltd.).

Next, a method for manufacturing the interior covering material 101 according to the first embodiment of this specification will be described. The method for manufacturing the interior covering material 101 according to the first embodiment includes the following steps: a carding process in which the synthetic resin fibers 1 used in the needle-punched nonwoven fabric 5 are unraveled to form a web (fibrous sheet); a needle-punching process in which the fibers in the formed web are entangled and bonded with tiny needle protrusions to form the needle-punched nonwoven fabric 5; a lamination process in which the needle-punched nonwoven fabric 5 and the permeation-preventing nonwoven fabric 20 are attached to each other by needle-punching to form the skin substrate 10; a smoothing process in which the skin substrate 10 is smoothed using a heated roller; and a coating process in which a synthetic resin emulsion containing thermally expandable capsules 70 is applied to the skin substrate 10 to form the synthetic resin porous layer 60, in that order. The lamination process and the smoothing process are steps that can be incorporated as necessary and can be omitted.

In the carding process, synthetic resin fibers 1, which are the raw material for the needle-punched nonwoven fabric 5, are mixed in a specific ratio, and the mixed fibers are loosened and arranged in a carding machine to form a sheet-like mass and a web.

In the needle punching process, needles (a flat plate with countless needles standing at roughly right angles on one side) are pressed against the web formed in the carding process at high speed and repeatedly, and the tiny protrusions of the needles entangle and bond the fibers to form the needle punched nonwoven fabric 5. In this embodiment, needle punching is performed on only one side of the web.

In the lamination process, the needle-punched nonwoven fabric 5 and the permeation-preventing nonwoven fabric 20 were attached together by needle punching to form the skin substrate 10. In this embodiment, needle punching was performed from the upper side (needle-punched nonwoven fabric 5 side). In an embodiment that does not include the permeation-preventing nonwoven fabric 20, the lamination process is omitted, and the needle-punched nonwoven fabric 5 itself becomes the skin substrate 10.

In the smoothing process, a heated roller is pressed against the upper side of the skin substrate 10, and the upper side of the skin substrate 10 is heated and smoothed. The temperature of the roller is adjusted to a temperature at which the synthetic resin fibers 1 forming the skin substrate 10 (needle-punched nonwoven fabric 5) soften and fuse together. When the synthetic resin fibers 1 are PET/low-melting point PET, the temperature of the roller is set to 190-200°C. The smoothing process is a process that is incorporated as needed and can be omitted.

In the coating process, a synthetic resin emulsion containing thermally expandable capsules 70 was applied to the back surface (lower side) of the skin substrate 10, and the synthetic resin porous layer 60 was formed by heating and drying. There are two types of coating methods: a method in which the synthetic resin emulsion is applied to the back surface of the skin substrate 10 using a doctor knife to form an impregnation layer 61, and a method in which a foamed synthetic resin emulsion is applied to the back surface of the skin substrate 10 to form a foam rubber layer 62. In the coating process, either the method in which the impregnation layer 61 is formed or the method in which the foam rubber layer 62 is formed is performed. The thermally expandable capsules 70 are mixed as necessary, and may be omitted depending on the embodiment. The thermally expandable capsules 70 thermally expand by heating and drying after the application of the synthetic resin emulsion.

The interior skin material 101 thus manufactured is formed from a skin substrate 10 made of synthetic resin fibers 1 having a thickness of 0.5 to 20 dtex and a base material of needle-punched nonwoven fabric 5 having a basis weight of 100 to 300 g/m ² , and a synthetic resin porous layer 60 formed on the underside thereof and having a coating amount of 20 to 100 g/m ² calculated as non-volatile content. Since the interior skin material 101 has a synthetic resin porous layer (synthetic resin porous layer 60) formed so as to fill the gaps in the skin substrate 10 (needle-punched nonwoven fabric 5), even if it does not contain an oil repellent, it is possible to suppress the penetration of the foamable resin when the foamable resin is filled on the back side of the substrate in a molding die and then heated.

The interior skin material 101 thus manufactured can have an air permeability of 10 to 100 cc/ ^cm2 /sec, thereby achieving both rigidity and resistance to resin seepage. In another embodiment, the air permeability can be 20 to 80 cc/ ^cm2 /sec, and in yet another embodiment, 25 to 55 cc/ ^cm2 /sec.

Second Embodiment
Hereinafter, an interior covering material 102 according to a second embodiment of the present specification will be described with reference to the drawings. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 2, the interior skin material 102 according to the second embodiment is formed by joining an upper skin substrate 10A and a lower skin substrate 10B by needle punching. Since the two layers of needle punched nonwoven fabric are joined by needle punching, the interior skin material 102 according to the embodiment can suppress the penetration of the foamable resin even without an oil repellent when the foamable resin is filled on the back side of the fabric in a mold and then heated by the two layers of needle punched nonwoven fabric. In the interior skin material 102 according to the second embodiment, an intermediate film layer 30 made of a synthetic resin film that suppresses the penetration of the foamable resin can be interposed between the upper skin substrate 10A and the lower skin substrate 10B.

The upper-layer skin substrate 10A is a nonwoven fabric formed from synthetic resin fibers 1 having a thickness of 0.5 to 20 dtex and having a basis weight of 50 to 200 g/m ² , which has been needle-punched, and the lower-layer skin substrate 10B is a nonwoven fabric formed from synthetic resin fibers 1 having a thickness of 0.5 to 20 dtex and having a basis weight of 50 to 200 g/m ² , which has been needle-punched. The synthetic resin fibers 1 used in the upper-layer skin substrate 10A and the lower-layer skin substrate 10B can be the same as the synthetic resin fibers 1 used in the needle-punched nonwoven fabric 5 of the first embodiment.

The intermediate film layer 30 is made of a synthetic resin film, and is a film that can be provided to further suppress the penetration of the foamable resin when the foamable resin is filled on the back surface of the interior skin material 102 and then heated. In an embodiment, the intermediate film layer 30 can be made of a polyester film, a polyolefin film (PE (polyethylene), PP (polypropylene), etc.), a PA (polyamide) film, an acrylic resin film, a polyvinyl alcohol film, etc. In addition, the intermediate film layer 30 can also be a multilayer film made by laminating these films, and can be made of either a stretched film or an unstretched film.

Next, a method for manufacturing the interior skin material 102 according to the second embodiment of this specification will be described. The method for manufacturing the interior skin material 102 according to the second embodiment includes a carding process for forming a web from the synthetic resin fiber 1 used for the upper skin substrate 10A (lower skin substrate 10B), a needle punching process for forming the upper skin substrate 10A (lower skin substrate 10B) from the formed web, a lamination process for laminating the upper skin substrate 10A, the lower skin substrate 10B, and a synthetic resin film (intermediate film layer 30) interposed therebetween by needle punching, and a smoothing process for smoothing the surface of the laminated multilayer skin substrate 10C using a heated roller. The synthetic resin film (intermediate film layer 30) is used as necessary and can be omitted.

The carding process and needle punching process are the same as those in the first embodiment.

In the bonding process, the upper skin substrate 10A, the lower skin substrate 10B, and the synthetic resin film (intermediate film layer 30) interposed therebetween are bonded together by needle punching. In an embodiment that does not include the intermediate film layer 30, the synthetic resin film is omitted.

In the smoothing process, a heated roller is pressed against the upper side or the upper and lower sides of the laminated multilayer skin substrate 10C, and the surface of the multilayer skin substrate 10C is heated and smoothed. The multilayer skin substrate 10C becomes the interior skin material 102 through the smoothing process. The roller temperature is set to the same temperature as that of the first embodiment.

The interior skin material 102 thus manufactured is a needle-punched upper-layer skin substrate 10A formed from synthetic resin fibers 1 having a thickness of 0.5 to 20 dtex and having a web having a basis weight of 50 to 200 g/m ² , a synthetic resin film (intermediate film layer 30) which is interposed as necessary, and a lower-layer skin substrate 10B formed from synthetic resin fibers 1 having a thickness of 0.5 to 20 dtex and having a web having a basis weight of 50 to 200 g/m ^2. Since the two layers of needle-punched nonwoven fabric are needle-punched, the interior skin material according to the embodiment, even if it does not contain an oil repellent, can suppress the penetration of the foamable resin when the foamable resin is filled on the back side of the fabric in a molding die and then heated by the two layers of needle-punched nonwoven fabric.

The present invention will be described in more detail below with reference to examples. The properties of the synthetic resin fiber 1 used are shown in Table 1, the properties of the permeation-blocking nonwoven fabric 20 in Table 2, the properties of the synthetic resin emulsion forming the synthetic resin porous layer 60 in Table 3, the properties of the thermally expandable capsules 70 in Table 4, and the properties of the intermediate film layer 30 in Table 5. The synthetic resin emulsion N in Table 3 is a mixture of an acrylonitrile-styrene-acrylic acid ester copolymer emulsion and an acrylonitrile-acrylic acid ester copolymer emulsion.

The performance of the interior skin materials 101 and 102 of the examples was evaluated in terms of normal incidence sound absorption coefficient, air permeability, rigidity, and resin seepage resistance. The evaluation methods are described below.

(Normal incidence sound absorption coefficient)
The normal incidence sound absorption coefficient was measured according to Measurement of sound absorption coefficient and impedance using an acoustic tube - Part 2: Transfer function method (JIS A 1405-2:2007 (ISO 10534-2:1998)). Then, it was evaluated as follows: better than the comparative example (Table 6), △, and worse than the comparative example.

(Ventilation volume)
The air permeability was measured according to 8.26 Air Permeability A (Fragile method) of the Fabric Testing Method for Woven and Knitted Fabrics (JIS L 1096:2010). The lower the air permeability value, the better the results.

(rigidity)
The rigidity was evaluated by comparing with the comparative example (Table 6). The rigidity was evaluated as follows: ◯: superior to the comparative example (Table 6), Δ: equivalent to the comparative example, and ×: inferior to the comparative example.

(Resin seepage resistance)
The resin bleeding resistance was evaluated by filling the back side of the interior covering materials 101, 102 with a foamable resin in a molding die, heating it, and checking the degree of bleeding to the front side of the interior covering materials 101, 102. The resin was then rated as ◯ when no bleeding was observed, △ when bleeding was observed but not to the extent that the texture of the surface was impaired, and × when bleeding was observed and the texture of the surface was impaired.

Table 6 shows the formulations and physical property evaluations for the examples and comparative examples of the first embodiment. The comparative examples are conventional interior skin materials. Examples 3 and 4 are examples in which the best mode is achieved. An enlarged photograph of the back surface of the interior skin material 101 of Example 3 is shown in FIG. 3, and an enlarged photograph of the back surface of the interior skin material 101 of Example 4 is shown in FIG. 4. Also, a graph of the normal incidence sound absorption coefficient of the floor carpets of Examples 3 and 4 (with a foamed resin layer F on the back side of the interior skin material 101) is shown in FIG. 5. The solid line is Example 3, and the dotted line is Example 4.

In Example 1, the basis weight of the needle-punched nonwoven fabric 5 was increased from the comparative example, and the amount of synthetic resin emulsion applied to form the synthetic resin porous layer 60 was increased. In Example 1, the resin seepage resistance was such that although seepage was noticeable, it was not so great that the texture of the surface was impaired.

In Example 2, by blending thermally expandable capsules 70 with the synthetic resin emulsion, it was possible to achieve resistance to resin bleeding, with no visible bleeding even when the amount of synthetic resin emulsion applied was reduced. It was also confirmed that the use of thermally expandable capsules 70 has the effect of filling the spaces between the fibers of the spunbond nonwoven fabric (permeation-resistant nonwoven fabric 20) and reducing breathability.

In Example 3, it was confirmed that high rigidity could be obtained by changing the synthetic resin emulsion to an acrylic synthetic resin emulsion containing acrylonitrile and styrene. It was also confirmed that resistance to resin seepage could be improved by increasing the amount of thermally expandable capsules 70.

In Example 4, even without the incorporation of the thermally expandable capsules 70, the foam rubber layer 62 (synthetic resin porous layer 60) is formed from a synthetic resin emulsion, as shown in FIG. 4, and the resin seepage resistance is such that no seepage is observed.

In Example 5, the synthetic resin emulsion was changed from an acrylic synthetic resin emulsion containing acrylonitrile and styrene to an acrylic synthetic resin emulsion, and a foam rubber layer 62 was formed from the synthetic resin emulsion in the same manner as in Example 4. Although the resistance to resin seepage was good, the acrylic synthetic resin emulsion did not sufficiently impregnate the skin substrate 10, resulting in poor rigidity.

In Example 6, the permeation-blocking nonwoven fabric 20 was changed to a wet-laid nonwoven fabric made of pulp and rayon. An interior covering material 101 with excellent performance was obtained.

In Example 7, the permeation-preventing nonwoven fabric 20 was changed to a melt-blown nonwoven fabric. An interior covering material 101 with excellent performance was obtained.

Table 7 shows the formulation and physical property evaluation of the example of the second embodiment.

In Example 8, the upper skin substrate 10A and the lower skin substrate 10B are needle punched. Both the front and back surfaces are smoothed with a heated roller, so the interior skin material 102 in Example 8 has excellent resistance to resin seepage and excellent rigidity.

In Example 9, the PP (polypropylene) fiber of the synthetic resin fiber 1 of the lower skin substrate 10B of Example 8 was changed to PET (polyester) fiber. During the smoothing process, the melting point of the PET fiber is high and it does not heat fuse, resulting in poor resistance to resin bleeding.

Example 10 is an example of Example 9 with an intermediate film layer 30 (single layer of polyurethane) added between the upper skin substrate 10A and the lower skin substrate 10B. The intermediate film layer 30 improved the resistance to resin seepage, but the intermediate film layer 30 also reduced the sound absorption. In addition, in the lamination process in which the two substrates are attached by needle punching, a large amount of film pieces adhered to the barbs of the needles, resulting in poor work efficiency.

In Example 11, the polyurethane single layer of the intermediate film layer 30 of Example 10 was changed to a three-layer film. The results were the same as in Example 10, with the intermediate film layer 30 improving the resistance to resin seepage, but resulting in poor sound absorption. Furthermore, by changing the intermediate film layer 30 to a three-layer film, adhesion of film pieces to the barbs of needles during the lamination process in which the films are attached by needle punching was reduced, making the product more practical.

1...synthetic resin fiber, 5...needle-punched nonwoven fabric, 10...skin substrate, 10A...upper layer skin substrate, 10B...lower layer skin substrate, 10C...multi-layer skin substrate, 20...permeation-preventing nonwoven fabric, 30...middle film layer, 60...synthetic resin porous layer, 61...impregnated layer, 62...foam rubber layer, 70...thermally expandable capsule, 101...interior skin material, 102...interior skin material, F...foamed resin layer.

Claims (8)

a skin substrate made of a needle-punched nonwoven fabric base material, the needle-punched nonwoven fabric base material being formed from synthetic resin fibers having a thickness of 0.5 to 20 dtex and having a basis weight of 100 to 300 g/ ^m2 ;
the surface substrate is provided with a permeation-preventing nonwoven fabric below the needle-punched nonwoven fabric, and the needle-punched nonwoven fabric and the permeation-preventing nonwoven fabric are needle-punched together;
a synthetic resin porous layer provided on the underside of the skin substrate and having a coating amount of 20 to 100 g/ ^m2 calculated as non-volatile content;
The synthetic resin porous layer is impregnated into the skin substrate,
The interior skin material is characterized in that thermally expandable capsules are mixed into the synthetic resin porous layer. 2. The interior covering material according to claim 1 , wherein the permeation-preventing nonwoven fabric is a spunbonded nonwoven fabric, a meltblown nonwoven fabric, or a wet-laid nonwoven fabric. 3. The interior skin material according to claim 1, wherein the synthetic resin emulsion forming the synthetic resin porous layer is an acrylic resin emulsion. 4. The interior skin material according to claim 3 , wherein the synthetic resin emulsion is an acrylic resin emulsion containing acrylonitrile and styrene. 5. The interior skin material according to claim 3 , wherein the glass transition temperature (Tg) of the resin constituting the synthetic resin emulsion is 10 to 20.degree. 6. The interior skin material according to claim 1 , wherein an upper side of the skin substrate is heated and smoothed. A method for producing an interior skin material according to claim 1 ,
a carding step of forming the web from the synthetic resin fibers having a thickness of 0.5 to 20 dtex and having a basis weight of 100 to 300 g/ ^m2 ;
a needle punching step in which the fibers of the formed web are entangled and bonded with tiny needle protrusions to form a needle punched nonwoven fabric;
a lamination step of laminating the needle-punched nonwoven fabric and the permeation-preventing nonwoven fabric by needle punching to form the skin substrate;
a coating step of coating the skin substrate with a synthetic resin emulsion containing the thermally expandable capsules to form the synthetic resin porous layer;
2. A method for producing an interior skin material comprising the steps of: 8. The method for producing an interior skin material according to claim 7, further comprising a smoothing step between the laminating step and the coating step , in which a heated roller is pressed against an upper side of the skin substrate to heat and smooth the upper side of the skin substrate.

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