JP7621050B2 - Interior Surface Materials - Google Patents

Description

The present invention relates to interior surface materials.

Conventionally, automotive interior surface materials have been used that include fiber sheets in which constituent fibers are integrated with adhesive components (such as binders or adhesive fibers). As an interior surface material of this type, the applicant of the present application proposed "an interior skin material in which one side of a fiber web is needle-punched, the needle-punched side is impregnated with a binder, the web is then calendered, and the opposite side to the needle-punched side is impregnated with a binder having low tack" (Patent Document 1) as described in JP-A-62-257472.

Japanese Unexamined Patent Publication No. 62-257472

The interior surface material according to the prior art is provided with a fiber sheet and is soft and highly flexible, so that when the interior surface material is pressed against a heated mold and subjected to a molding process in which the material is given the shape of the mold, the interior surface material stretches and conforms to the internal shape of the mold, allowing the production of an interior material molded into the intended shape (excellent moldability).
However, when the prepared interior material was placed on a punching table and punched out with a die blade to form the desired shape, parts of the punched interior material had loose, protruding fibers on the cross section, indicating poor trimming properties.

The present invention aims to provide an interior surface material that can be used to prepare interior materials with excellent trimming properties.

The present invention relates to a surface material for interior use that is a fiber sheet having a thickness of 1.1 mm or more, in which constituent fibers having a fiber length of 25 mm or more and 76 mm or less are integrated with each other by an adhesive component (excluding those in which the constituent fibers are made only of fibers composed of polyester-based resin),
The constituent fibers of the fiber sheet are rayon fibers and polyester-based resin fibers,
After heat treatment under the following conditions, which are the measurement method, the average values of the longitudinal tear strength and transverse tear strength per basis weight are 0.18 (unit: N/(g/m ² )) or less;
The average value of the 20% modulus in the warp direction divided by the basis weight and the 20% modulus in the cross direction divided by the basis weight is less than 1.13.
Interior surface materials.
Note 1. The interior surface material was placed in a heat press device, and the interior surface material was sandwiched between an upper heating plate and a lower heating plate adjusted to a heating temperature of 200° C. and heated for 5 seconds. The gap distance between the upper heating plate and the lower heating plate during heating was 1.0 mm.
2. The interior surface material that had been subjected to the heat treatment was removed from the heat press device and placed in an atmosphere at room temperature (25° C.) to cool and then subjected to the heat treatment.

As a result of investigations, the applicant of the present application has found that the trimmability of an interior material obtained by subjecting an interior surface material having a fiber sheet in which constituent fibers are integrated together by an adhesive component to a molding process does not depend solely on the composition of the fibers that make up the interior surface material, the degree of entanglement of the constituent fibers of the interior surface material, or the degree of integration of the fibers that make up the interior surface material.
The inventors have also discovered that by using an interior surface material comprising a fiber sheet of this configuration, in which the average longitudinal tear strength and transverse tear strength per basis weight after the heat treatment according to the present invention is less than 0.21, it is possible to provide an interior surface material with excellent trimmability.
The reason for this has not been fully elucidated, but in order to provide an interior material with excellent trimmability, it is necessary to realize an interior material with a structure that allows it to be easily torn apart, starting from the cut formed by the die blade when a force (tension) is applied to the interior material with the die blade to punch it out.
The inventors have found that in order to realize an interior material having the above-mentioned structure, it is necessary to prepare the interior material using an interior surface material having a structure that allows easy tearing with little tension from the formed cut as the starting point. Furthermore, the inventors have found that whether an interior surface material has the above-mentioned structure can be evaluated by the average values of the longitudinal tear strength and transverse tear strength per basis weight of the interior surface material after the heat treatment according to the present invention has been performed.
As described above, the present invention provides an interior material having excellent trimming properties.

In the present invention, various configurations can be appropriately selected, for example, the following configurations.
The interior surface material of the present invention includes a fiber sheet, which is a sheet-like fiber assembly such as a fiber web, a nonwoven fabric, or a woven or knitted fabric. The fiber sheet of the present invention has fibers that constitute the fiber sheet integrated together with an adhesive component. For example, the fibers that form the main skeleton of the fiber sheet are bonded and fixed together with a binder or a thermally adhesive fiber contained in the fiber sheet.

The interior surface material of the present invention is soft and highly flexible because it contains a fiber sheet (particularly a fiber web or nonwoven fabric). Therefore, by subjecting the interior surface material to a molding process in which it is pressed against a heated mold and given the shape of the mold, the interior surface material stretches and conforms to the internal shape of the mold, allowing the production of an interior material molded into the intended shape.

The fibers forming the main skeleton of the fiber sheet are, for example, polyolefin resins (e.g., polyethylene, polypropylene, polymethylpentene, polyolefin resins having a structure in which a portion of a hydrocarbon is substituted with a cyano group or a halogen such as fluorine or chlorine, etc.), styrene resins, polyvinyl alcohol resins, polyether resins (e.g., polyether ether ketone, polyacetal, modified polyphenylene ether, aromatic polyether ketone, etc.), polyester resins (e.g., polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyarylate, wholly aromatic polyester resins, etc.), polyimide resins, It can be constructed using known organic resins such as resin, polyamideimide resin, polyamide-based resin (e.g., aromatic polyamide resin, aromatic polyetheramide resin, nylon resin, etc.), resin having a nitrile group (e.g., polyacrylonitrile, etc.), urethane-based resin, epoxy-based resin, polysulfone-based resin (e.g., polysulfone, polyethersulfone, etc.), fluorine-based resin (e.g., polytetrafluoroethylene, polyvinylidene fluoride, etc.), cellulose-based resin, polybenzimidazole resin, acrylic-based resin (e.g., polyacrylonitrile-based resin copolymerized with acrylic acid ester or methacrylic acid ester, modacrylic-based resin copolymerized with acrylonitrile and vinyl chloride or vinylidene chloride, etc.).
These organic resins may be either linear or branched polymers, may be block or random copolymers, may have any three-dimensional structure, may have any crystallinity, or may be a mixture of multiple organic resins.

When flame retardancy is required for the interior surface material, it is preferable that the fiber forming the main skeleton of the fiber sheet contains a flame-retardant organic resin. Examples of such flame-retardant organic resins include modacrylic resins, vinylidene resins, polyvinyl chloride resins, polyvinylidene fluoride resins, novoloid resins, polyclar resins, polyester resins copolymerized with phosphorus compounds, acrylic resins copolymerized with halogen-containing monomers, aramid resins, and resins kneaded with halogen-based, phosphorus-based, or metal compound-based flame retardants. The fiber sheet may also contain flame-retardant fibers such as rayon fibers as the main skeleton of the fiber sheet.

When the fiber sheet contains thermally adhesive fibers, the fibers constituting the main skeleton of the fiber sheet can be bonded together, or the fibers constituting the main skeleton of the fiber sheet and the thermally adhesive fibers, by heating the thermally adhesive fibers, which is preferable because it gives the fiber sheet strength and dimensional stability. Well-known thermally adhesive fibers can be used, for example, fully fused thermally adhesive fibers or partially fused thermally adhesive fibers such as the composite fibers described below. As a component that exhibits thermal adhesion in the thermally adhesive fibers, for example, thermally adhesive fibers containing low-melting point polyolefin resins or low-melting point polyester resins can be appropriately selected and used.

The amount of the thermally adhesive fiber contained in the fiber sheet is appropriately selected, but the greater the amount of the thermally adhesive fiber, the easier it is to provide an interior surface material with excellent trimming properties, but if the amount is too much, it tends to be difficult to provide an interior surface material with excellent flexibility. Therefore, the percentage of the thermally adhesive fiber mass in the fiber mass constituting the fiber sheet is preferably 70 mass% or less, more preferably 60 mass% or less, and more preferably 50 mass% or less.
On the other hand, the smaller the amount of thermal adhesive fibers contained in the fiber sheet, the easier it is to provide an interior surface material with excellent flexibility, but if the amount is too small, it tends to be difficult to provide an interior surface material with excellent trimming properties. Therefore, the percentage of the thermal adhesive fiber mass in the fiber mass constituting the fiber sheet is preferably 10 mass% or more.

The constituent fibers of the fiber sheet can be obtained by known methods such as melt spinning, dry spinning, wet spinning, direct spinning (melt blowing, spunbonding, electrostatic spinning, etc.), a method of extracting fibers with a small fiber diameter by removing one or more resin components from composite fibers, and a method of beating fibers to obtain split fibers.

The constituent fibers may be made of one type of organic resin or a plurality of types of organic resins. Fibers made of a plurality of types of organic resins may be in the form of what is generally called composite fibers, such as a core-sheath type, a sea-island type, a side-by-side type, an orange type, a bimetal type, or the like.
The constituent fibers may include irregular cross-section fibers other than the substantially circular or elliptical fibers. The irregular cross-section fibers may have a fiber cross section of a hollow shape, a polygonal shape such as a triangular shape, an alphabetic shape such as a Y-shape, an irregular shape, a multi-lobed shape, a symbolic shape such as an asterisk shape, or a shape in which a plurality of these shapes are combined.

When the fiber sheet contains crimpable fibers, the elasticity of the fiber sheet increases and it is preferable that the fiber sheet has excellent conformity to the mold. As such a crimpable fiber, for example, a crimpable fiber that has expressed the crimp of a latent crimpable fiber or a fiber having a crimp can be used. The fiber sheet may also contain a latent crimpable fiber that expresses crimp when heated.

When the fiber sheet is a fiber web or nonwoven fabric, it can be prepared by, for example, a dry method in which the constituent fibers are fed to a carding device or an air-laying device to entangle the fibers, a wet method in which the fibers are dispersed in a solvent and formed into a sheet, or a method in which the constituent fibers are spun and collected using a direct spinning method (such as a melt-blowing method, a spunbonding method, an electrostatic spinning method, or a method in which a spinning solution and a gas flow are discharged in parallel to spin the fibers (e.g., the method disclosed in JP-A-2009-287138), etc.).
Furthermore, the constituent fibers of the prepared fiber web can be entangled to prepare a fiber sheet made of a nonwoven fabric. For example, entanglement can be performed using a needle or a water stream.

When the fiber sheet is a woven or knitted fabric, the woven or knitted fabric can be prepared by weaving or knitting the fibers prepared as described above.

The fineness of the constituent fibers of the fiber sheet is not particularly limited, but in order to provide an interior surface material with appropriate rigidity, it is preferably 1 dtex or more, more preferably 1.5 dtex or more, and even more preferably 2 dtex or more. On the other hand, in order to be able to prepare an interior surface material with a homogeneous texture and to provide a soft interior surface material with high flexibility, it is preferably 100 dtex or less, more preferably 50 dtex or less, more preferably 30 dtex or less, and even more preferably 20 dtex or less.

The fiber length of the fibers constituting the fiber sheet is not particularly limited, but is preferably 20 mm or more, more preferably 25 mm or more, and even more preferably 30 mm or more, so as to provide an interior surface material with appropriate rigidity. On the other hand, if the fiber length exceeds 110 mm, fiber clumps tend to form during preparation of the fiber sheet, making it difficult to prepare an interior surface material with a homogeneous texture and to provide a soft interior surface material with excellent flexibility. Therefore, the fiber length is preferably 110 mm or less, and more preferably 60 mm or less.
The "fiber length" refers to a value measured in accordance with JIS L1015 (2010), 8.4.1c) direct method (method C).

In the case of a fiber sheet in which the constituent fibers of the fiber sheet are bonded together with a binder, the binder may be present in the form of a film, particles or in an indefinite form on a part or the entire surface of the constituent fibers.
The binder may be present uniformly throughout the fiber sheet, or may be present in such a way that the amount of the binder decreases or increases from one main surface of the fiber sheet to the other main surface, or may be present only on one or the other main surface of the fiber sheet. In order to provide an interior surface material that has excellent trimming properties, it is preferable that the binder is present in such a way that the amount of the binder increases from one main surface of the fiber sheet to the other main surface. A fiber sheet of this type can be prepared by applying an entanglement means such as a needle or a water flow from one side to the main surface on the side where the entanglement means has been applied, and then applying a binder liquid to the main surface on the side where the entanglement means has been applied.

The type of binder is appropriately selected, and examples of the binder that can be used include polyolefins (such as modified polyolefins), ethylene-vinyl alcohol copolymers, ethylene-acrylate copolymers such as ethylene-ethyl acrylate copolymers, various rubbers and their derivatives [styrene-butadiene rubber (SBR), fluororubber, urethane rubber, ethylene-propylene-diene rubber (EPDM), etc.], cellulose derivatives [carboxymethyl cellulose (CMC), hydroxyethyl cellulose, hydroxypropyl cellulose, etc.], polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylpyrrolidone (PVP), polyurethane, epoxy resins, polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), acrylic resins, and the like.
If the binder contains an acrylic resin, it is preferable that the binder softens appropriately during heat molding such as heat pressing using a mold, and therefore provides an interior surface material that has excellent conformity to the mold. In addition to the above-mentioned resins, the binder may contain additives such as flame retardants, fragrances, pigments, antibacterial agents, antifungal agents, photocatalyst particles, emulsifiers, dispersants, and surfactants.

The basis weight (solid basis weight) of the binder contained in the fiber sheet is appropriately selected, but the more the binder content, the easier it is to provide an interior surface material with excellent trimming properties, but if the binder content is too high, it tends to be difficult to provide an interior surface material with excellent flexibility. Therefore, the basis weight of the binder is preferably 50 g/m2 or ^less , more preferably 30 g/m2 or ^less , more preferably 20 g/ ^m2 or less, and more preferably 15 g/m2 or ^less .
On the other hand, the smaller the amount of binder, the easier it is to provide an interior surface material with excellent flexibility, but if the amount of binder is too small, it tends to be difficult to provide an interior surface material with excellent trimming properties. Therefore, the weight of the binder is preferably 2 g/ ^m2 or more.

The various configurations of the fiber sheet, such as thickness and basis weight, are appropriately adjusted so as to provide the interior surface material according to the present invention.
The thickness of the fiber sheet is preferably 0.5 mm to 10 mm, more preferably 1 mm to 7 mm, and most preferably 1.1 mm to 5 mm. The basis weight of the fiber sheet is, for example, preferably 50 to 600 g/ ^m2 , more preferably 80 to 550 g/ ^m2 , and most preferably 100 to 250 g/ ^m2 .
In the present invention, the thickness refers to the length perpendicular to the main surface of the object to be measured, measured using a Litematic (registered trademark) thickness gauge manufactured by Mitutoyo Corporation (compression probe: 5 ^cm2 , compression load: 2.0 kPa), and the basis weight refers to the mass per ^m2 on the surface having the widest area (main surface) of the object to be measured.

The interior surface material of the present invention may have a printed layer as a component other than the fiber sheet. The printed layer here refers to a layer containing a resin that is present on one main surface of the fiber sheet.
The type of resin constituting the print layer can be appropriately selected, and the same resin as the binder described above can be used. In particular, it is preferable that the resin constituting the print layer contains an acrylic resin, since this can provide an interior surface material that is appropriately softened during heat molding such as heat pressing using a mold and has excellent mold conformability.
In addition to the resin constituting the print layer, the print layer may contain additives such as flame retardants, fragrances, pigments, antibacterial agents, antifungal materials, photocatalyst particles, emulsifiers, dispersants, surfactants, etc. In particular, when the print layer contains a pigment, it is preferable because it is possible to provide an interior surface material with excellent design.

The form of the printed layer present on one of the main surfaces of the fiber sheet can be appropriately selected, and may be a form in which the printed layer is present so as to cover the entire surface of the main surface, or a form in which the printed layer is present so as to cover a part of the main surface so as to form a pattern of lines, dots, irregular shapes, etc. Furthermore, the fiber sheet may have a plurality of layers containing one or a plurality of types of resin, and specifically, the fiber sheet may have a plurality of printed layers having the same or different patterns, constituent resins, or ingredients.
The printed layer may be present on the main surface that is exposed to the vehicle space or building space when the prepared interior material is used, or may be present on both main surfaces.
In addition to the embodiment in which the printed layer is present only on the main surface of the fiber sheet, a part of the components such as the resin constituting the printed layer may penetrate between the constituent fibers of the fiber sheet.
The basis weight of the print layer is appropriately selected, but can be, for example, 2 to 50 g/ ^m2 , and can be 10 to 30 g/ ^m2 .

The interior surface material of the present invention comprises the above-mentioned fiber sheet.
The basis weight of the interior surface material is appropriately adjusted so as to provide the interior surface material according to the present invention, but can be 600 g/m2 or ^less , and can be 550 g/m2 or ^less . On the other hand, the lower limit of the basis weight is appropriately adjusted, but it is practical to set it to 10 g/m2 ^{or more} .
The thickness of the interior surface material is appropriately adjusted so as to provide the interior surface material according to the present invention, but can be 5 mm or less, and can be 4 mm or less, while the lower limit of the thickness is preferably thicker than 1 mm so as to be capable of being subjected to the heat treatment specified in the present invention.
The apparent density of the interior surface material is appropriately adjusted so as to provide an interior surface material that is excellent in sound absorbing performance and cushioning properties, and can be 0.101 g/cm ³ to 0.300 g/cm ³ .

The interior surface material of the present invention has an average longitudinal tear strength and transverse tear strength per unit area of less than 0.21 after heat treatment under the conditions described below.

(Heat treatment conditions)
1. The interior surface material was placed in a heat press device , and heated for 5 seconds while being sandwiched between an upper heating plate and a lower heating plate adjusted to a heating temperature of 200° C. The gap distance between the upper heating plate and the lower heating plate during heating was 1.0 mm.
2. The interior surface material that had been subjected to the heat treatment was removed from the heat press device and placed in an atmosphere at room temperature (25° C.) to cool, thereby preparing a heat-treated interior surface material.

When an interior surface material is subjected to a molding process in which it is pressed against a heated mold and given the shape of the mold, the heating conditions for the interior surface material in the molding process are generally stricter than those of the heat treatment of the present invention, in that the heating conditions are higher, the treatment time is longer, and the gap distance is smaller. In other words, interior surface materials subjected to a general molding process are forcibly molded under the strict molding conditions described above, and therefore it is difficult to recognize the problems that the prepared interior material has poor trimming properties and that the interior surface material has poor moldability during the molding process.
On the other hand, the heat treatment according to the present invention is not necessarily higher than the general molding process, the treatment time is not long, and the gap distance is smaller, so the pressurization conditions are not stricter, and therefore the conditions can be said to be less forcibly molding the interior surface material than in the general molding process. In other words, with the interior surface material subjected to the heat treatment according to the present invention, it is easy to recognize problems such as poor trimming properties of the prepared interior surface material and poor moldability during the molding process.

Therefore, by evaluating the trimmability and moldability of an interior surface material that has been heat-treated according to the present invention, it is possible to estimate the results (trimability and moldability) of subjecting the interior surface material to a general molding process. In other words, if the trimmability and moldability of an interior surface material that has been heat-treated according to the present invention are excellent, then by using the interior surface material, it is possible to provide an interior material with even better trimmability and moldability.

The average longitudinal tear strength and transverse tear strength per basis weight are calculated using the following measurement method.

(Method for measuring average values of longitudinal tear strength and transverse tear strength per basis weight)
(1) Using a sample taken from a measurement object, such as an interior surface material after the heat treatment according to the present invention, the tear strength (unit: N) in the longitudinal and transverse directions of the measurement object was determined according to the method specified in 6.4.3 (single tongue method) of JIS L1913-2010. Note that the measurement was performed with the direction parallel to the production direction of the measurement object (generally the orientation direction of the fibers) as the longitudinal direction, and the direction perpendicular to the production direction of the measurement object as the transverse direction.
(2) The vertical tear strength (unit: N) of the object to be measured was divided by its basis weight (unit: g/m2 ⁾ , and the average value was calculated by dividing the horizontal tear strength (unit: N) of the object to be measured by its basis weight (unit: g/m2 ⁾ . This was used as the average vertical tear strength and horizontal tear strength per basis weight unit (unit: N/(g/m2 ⁾ ) .

The average value can be said to be a schematic representation of the ease of tearing from the cut in the measured object. The lower the average value, the easier it is to tear with less tension from the cut that is formed (in other words, from the starting point of the trimming by the die blade when the object is placed on the punching table and punched).
Therefore, the lower the average value of the interior surface material, the more excellent the trimming property of the interior surface material that can be prepared. The average value is less than 0.21, preferably 0.18 or less, and more preferably 0.15 or less. The lower limit is appropriately selected, but a too low average value means that the rigidity is too low, making it difficult to provide an interior material that satisfies the required rigidity, so it is preferably 0.05 or more.

Furthermore, the values of the 20% modulus (unit: N/50 mm), tensile strength (unit: N/50 mm), and tensile elongation (%) in the warp and weft directions of the interior surface material are appropriately adjusted so as to provide the interior surface material of the present invention. Each value can be determined by the following measurement method.

(Method of measuring 20% modulus)
(1) A total of three rectangular specimens C (long side: 200 mm, short side (perpendicular to the long side): 50 mm) were taken from the object to be measured, such as an interior surface material. The production direction of the object to be measured was parallel to the long side direction.
(2) The sample C was fixed to the chuck (chuck distance: 150 mm) of a tensile strength tester (Tensilon UTM-III-100 (registered trademark), manufactured by Orientec), and pulled at a tensile speed of 200 mm/min., and the stress at 20% elongation when the chuck distance became 180 mm was measured. The stress was measured for each of the three prepared samples C, and the arithmetic average was taken as the 20% modulus (unit: N/50 mm) in the longitudinal direction of the measurement target.
(3) A total of three rectangular samples D (long side: 200 mm, short side (perpendicular to the long side): 50 mm) were taken from the measurement object. The production direction of the measurement object was parallel to the short side direction.
(4) The stress at 20% elongation was measured by subjecting the sample D to the same measurement as in (2) above. The stress was measured for each of the three prepared samples D, and the arithmetic average was taken as the 20% modulus (unit: N/50 mm) in the transverse direction of the measurement subject.

The lower the 20% modulus, the softer the material is. Therefore, an interior surface material with a low 20% modulus has excellent moldability because, when subjected to a molding process, the interior surface material stretches and easily conforms to the internal shape of the mold, allowing the production of an interior material molded into the intended shape.
For this reason, the 20% modulus is preferably 1000N/50mm or less in both the vertical and horizontal directions, more preferably 750N/50mm or less, and more preferably 500N/50mm or less. The lower limit is appropriately selected, but if the 20% modulus is too low, the interior surface material may be too soft during trimming and may unintentionally deform, so the 20% modulus is preferably 100N/50mm or more in both the vertical and horizontal directions.

In addition, the average value of the measured 20% modulus in the longitudinal direction of the interior surface material divided by the basis weight of the interior surface material and the measured 20% modulus in the transverse direction of the interior surface material divided by the basis weight of the interior surface material (hereinafter sometimes referred to as the average 20% modulus per unit basis weight) can be said to represent the ease of elongation of the interior surface material.
The average value can be adjusted as appropriate, but since the lower the average value, the more excellent the moldability of the interior surface material, it is preferable that the average value is less than 1.13, and preferably 0.65 or less. The lower limit value is selected as appropriate, but if the average value is too low, the interior surface material may be too soft during trimming and may be unintentionally deformed, so the lower limit value is preferably 0.2 or more.

(Method of measuring tensile strength)
The tensile strength (unit: N/50 mm) in the longitudinal and transverse directions of the interior surface material was determined for each of Samples C and D by calculating, instead of the stress at 20% elongation in the above-mentioned (method of measuring 20% modulus), the average value of the maximum stress of each of Samples C and D measured until the sample broke.

The tensile strength is adjusted as appropriate, but is preferably 100 to 1000 N/50 mm in both the warp and weft directions, more preferably 200 to 900 N/50 mm, and even more preferably 300 to 850 N/50 mm.

(Method of measuring tensile elongation)
The tensile elongation (unit: %) in the longitudinal and transverse directions of the interior surface material can be calculated by inputting the chuck distance at which the sample broke during the above-mentioned tensile strength measurement into the following formula, and the average value of each chuck distance at which each of Samples C and D broke was calculated for each of Samples C and D.
Tensile elongation (%) = 100 × {(E/150) - 1}
E: Distance between chucks when the sample breaks (unit: mm)
The tensile elongation is adjusted appropriately, but is preferably 20 to 170%, more preferably 25 to 160%, and even more preferably 30 to 150%, in both the longitudinal and transverse directions.

The interior surface material of the present invention may further comprise other components such as a porous body, a film, a foam, etc. These components may be laminated on one or both main surfaces of the interior surface material.
The interior surface material may also contain additives such as flame retardants, fragrances, pigments, antibacterial agents, antifungal agents, photocatalyst particles, emulsifiers, dispersants, and surfactants.

Next, a method for producing the interior surface material of the present invention will be described, with a description omitted for the same points as those described above for the interior surface material.
The method for producing the interior surface material according to the present invention can be appropriately selected. As an example,
(1) preparing a fiber sheet including a main frame fiber and a thermal adhesive fiber;
(2) A step of applying heat to the fiber sheet to melt or soften the adhesive component of the thermal adhesive fiber;
(3) A process of cooling the fiber sheet to bond and integrate the fibers constituting the main skeleton of the fiber sheet with each other and/or the fibers constituting the main skeleton of the fiber sheet with the thermal adhesive fibers by the adhesive component of the thermal adhesive fibers;
A method for producing an interior surface material comprising the steps of:

First, step (1) will be described.
A sheet-like fabric, such as a fiber web, a nonwoven fabric, a woven fabric, a knitted fabric, or the like, is prepared, which is made of a main fiber and a thermal adhesive fiber. The fineness and length of the constituent fibers of the fiber sheet, the thickness and basis weight of the fiber sheet, and other configurations can be those described above.

Next, the step (2) will be described.
The method of applying heat to the fiber sheet can be appropriately selected, for example, a method of heating or heating and pressing with a roll, or a method of subjecting the sheet to a heater such as an oven dryer, far-infrared heater, dry heat dryer, or hot air dryer. The temperature for melting or softening the adhesive component of the thermal adhesive fiber is appropriately adjusted depending on the relationship between the melting point, glass transition temperature, or decomposition start temperature of the components other than the adhesive component constituting the fiber sheet and the temperature at which the adhesive component of the thermal adhesive fiber exerts its adhesive function, such as the melting point or glass transition temperature of the adhesive component. Specifically, it is preferable to adjust the heating temperature of the fiber sheet so that the components constituting the fiber sheet other than the adhesive component of the thermal adhesive fiber do not melt, soften, or decompose, or are otherwise denatured, and that only the adhesive component of the thermal adhesive fiber melts or softens to exert its adhesive function.

Step (3) will now be described.
The method for cooling the fiber sheet after the above-mentioned step (2) can be appropriately selected, and examples of the method include a method of cooling by leaving it to stand in a room temperature atmosphere, a method of subjecting it to a cooling device such as a cooling roll, etc. The cooling temperature can also be appropriately adjusted, and is preferably a temperature lower than the heating temperature by the above-mentioned heating device, specifically, a temperature lower than the melting point or glass transition temperature of the adhesive component of the thermal adhesive fiber.
By cooling, the fibers that form the main skeleton of the fiber sheet and/or the fibers that form the main skeleton of the fiber sheet and the thermally adhesive fibers can be fixed together by the adhesive component of the thermally adhesive fibers, and a fiber sheet in which the constituent fibers are integrated together by the adhesive component can be prepared.

Furthermore, the fiber sheet prepared as described above may be used as a surface material for interior decoration as it is, but if necessary, a printed layer may be provided on at least one of the main surfaces of the fiber sheet to be used as a surface material for interior decoration.
A printed layer refers to a layer containing a resin, and a printed layer can be provided on the main surface of a fiber sheet by applying a printing liquid containing a resin (resin solution or resin dispersion) onto one main surface of the fiber sheet and then removing the solvent or dispersion medium from the printing liquid.
The type of resin, solution or dispersion medium constituting the printing liquid, the type of additive, the application method and application mode, and the method of removing the solvent or dispersion medium from the printing liquid can be appropriately selected.
In particular, when the printing liquid contains a pigment, it is preferable because it is possible to provide an interior surface material having excellent design. The printing liquid may be applied to one or both main surfaces of the fiber sheet.

Furthermore, the fiber sheet may be subjected to a pressure treatment process such as a reliant press process to smooth the surface. The pressure method and pressure conditions may be appropriately selected, and if necessary, a heat and pressure treatment may be performed. The pressure conditions and heating temperature are adjusted so that the shape and function of the components constituting the fiber sheet are not unintentionally deteriorated.
The interior surface material may also be manufactured through various secondary processes, such as a process of laminating other components such as other porous bodies, films, or foams, or a process of processing the material by punching out a shape according to the intended use or mode of use.

The present invention will be described in detail below with reference to examples, but these are not intended to limit the scope of the present invention.

(Comparative Example 1)
The fibers were mixed according to the composition described below, and the fibers were opened by a carding machine to prepare a fiber web.
Main fiber 1:
Polyester fiber (fineness: 13 dtex, fiber length: 51 mm, fiber color: black, melting point: 240°C) 55% by mass,
Main fiber 2:
Polyester fiber (fineness 6.6 dtex, fiber length 51 mm, fiber color: white, melting point: 240°C) 5% by mass,
Main fiber 3:
5% by mass of rayon fiber (fineness: 3.3 dtex, fiber length: 60 mm, fiber color: black, decomposition temperature: 260° C.),
Thermo-bondable fibers:
Low melting point polyester fiber (fineness: 4.4 dtex, fiber length: 51 mm, fiber color: black, melting point: 120°C) 35% by mass,
The prepared fiber web was then needle-punched from one side at a needle density of 293 needles/ ^m2, and then needle-punched from the opposite side at a needle density of 90 needles/ ^m2 to prepare a needle-punched nonwoven fabric.
The prepared needle-punched nonwoven fabric was then fed between heated rolls (gap interval: 1.2 mm, roll heating temperature: 160° C.) to melt the thermal adhesive fibers, and then allowed to cool to room temperature to prepare a fiber sheet (basis weight: 503 g/m ² , thickness: 3.1 mm) in which the fibers constituting the various main skeletons were bonded and integrated with each other by the adhesive component (low melting point polyester resin) derived from the thermal adhesive fibers.

(Comparative Example 2)
A fiber sheet (basis weight: 496 g/m2, thickness: 3.3 mm) was prepared in the same manner as in Comparative Example 1, except that polyester fiber (fineness: 11 dtex, fiber length: 51 mm, fiber color: black, melting point: 240°C) was used as fiber 1 constituting the main skeleton. In the same manner as in Comparative Example ¹ , various main skeleton fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

(Comparative Example 3)
A fiber sheet (basis weight: 528 g/m2, thickness: 3.2 mm) was prepared in the same manner as in Comparative Example 1, except that polyester fiber (fineness: 13 dtex, fiber length: 76 mm, fiber color: black, melting point: 240°C) was used as fiber 1 constituting the main skeleton. In the same manner as in Comparative Example ¹ , various main skeleton fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

(Comparative Example 4)
A fiber sheet (basis weight: 501 g/m2, thickness: 3.3 mm) was prepared in the same manner as in Comparative Example 1, except that polyester fiber (fineness: 11 dtex, fiber length: 76 mm, fiber color: black, melting point: 240°C) was used as fiber 1 constituting the main skeleton. In the same manner as in Comparative Example ¹ , various main skeleton fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

(Comparative Example 5)
A fiber sheet (basis weight: 481 g/ ^m2 , thickness: 2.7 mm ⁾ was prepared in the same manner as in Comparative Example 1, except that needle punching was performed on one side of the fiber web at a needle density of 468 needles/m2, and then needle punching was performed on the opposite side at a needle density of 250 needles/ ^m2 to prepare a needle punched nonwoven fabric, in which various main skeletal fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

(Comparative Example 6)
A fiber sheet (basis weight: 467 g/m2, thickness: 3.3 mm) was prepared in the same manner as in Comparative Example 4, except that a low melting point polyester fiber (fineness: 4.4 dtex, fiber length: 38 mm, fiber color: ^black , melting point: 120°C) was used as the thermal adhesive fiber. The fibers constituting the main skeleton were bonded together with an adhesive component derived from the thermal adhesive fiber (low melting point polyester resin).

Example 1
The surface interior material of Comparative Example 4 was heated for 20 seconds by sandwiching the needle-punched nonwoven fabric between the upper and lower heating plates, the heating temperature of which was adjusted to 200° C. The gap distance between the upper and lower heating plates during heating was 1.0 mm. In this manner, a fiber sheet (basis weight: 501 g/m 2 , thickness: 1.8 mm) was prepared in which the fibers constituting the various main skeletons were bonded and integrated with each other by the adhesive component ( ^low melting point polyester resin) derived from the thermal adhesive fiber.

Example 2
A fiber sheet (basis weight: 502 g/ ^m2 , thickness: 3.0 mm ⁾ was prepared in the same manner as in Comparative Example 4, except that needle punching was performed on one side of the fiber web at a needle density of 326 needles/m2, and then needle punching was performed on the opposite side at a needle density of 150 needles/ ^m2 to prepare a needle-punched nonwoven fabric, in which various main skeletal fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

Example 3
Except for changing the type of needle used for needle punching, a fiber sheet (basis weight: 514 g/ ^m2 , thickness: 3.1 mm) was prepared in the same manner as in Example 2, in which various main skeletal fibers were bonded together with an adhesive component (low melting point polyester resin) derived from a thermal adhesive fiber.

Example 4
A fiber sheet (basis weight: 514 g/ ^m2 , thickness: 2.6 mm) was prepared in the same manner as in Comparative Example 1, except that needle punching was performed on one side of the fiber web at a needle density of 586 needles/ ^m2 , and then needle punching was performed on the opposite side at a needle density of 180 needles/ ^m2 to prepare a needle-punched nonwoven fabric, in which various main skeletal fibers were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

Example 5
The fibers were mixed according to the composition described below and fed to a carding machine to open the fibers and form a fiber web.
Main fiber 1:
Polyester fiber (fineness: 11 dtex, fiber length: 76 mm, fiber color: black, melting point: 240°C) 45% by mass,
Main fiber 2:
Polyester fiber (fineness 6.6 dtex, fiber length 51 mm, fiber color: white, melting point: 240°C) 5% by mass,
Main fiber 3:
5% by mass of rayon fiber (fineness: 3.3 dtex, fiber length: 60 mm, fiber color: black, decomposition temperature: 260° C.),
Thermo-bondable fibers:
Low melting point polyester fiber (fineness: 4.4 dtex, fiber length: 51 mm, fiber color: black, melting point: 120°C) 45% by mass,
Except for using the fiber web thus prepared, a fiber sheet (basis weight: 535 g/m2, thickness: 3.7 mm) was prepared in the same manner as in Comparative Example ¹ , in which various fibers constituting the main skeleton were bonded together with an adhesive component derived from a thermal adhesive fiber (low melting point polyester resin).

Each of the fiber sheets prepared as described above was used as a surface material for interior decoration as it was, and various physical properties were measured. The results are summarized in Table 1.
In Table 1, the column "Average value A" means the average values of the longitudinal tear strength and transverse tear strength per unit basis weight, and the column "Average value B" means the average value of the 20% modulus per unit basis weight.

The "Trimability" and "Moldability" columns in Table 1 show the results of evaluating interior surface materials by subjecting them to the following measurement methods.

(Method of evaluating trimming ability)
The interior surface material was subjected to the treatment method described in the section "Conditions for heat treatment" to prepare an interior surface material after heat treatment. The interior surface material after heat treatment was placed on a punching table and punched out with a die blade. The cross section was visually inspected and the trimmability was evaluated according to the following criteria.
○: No part in which fibers protruded from the cross section of the interior surface material after the heat treatment as if they had come loose (part in which fibers protruded from the cross section by a length of 10 mm or more) was observed. Therefore, the interior surface material was evaluated as an interior surface material that can be used to prepare an interior material with excellent trimming properties.
×: After the heat treatment, there were observed portions in which fibers protruded from the cross section of the interior surface material as if they had come loose (portions in which fibers protruded from the cross section by a length of 10 mm or more). Therefore, the interior surface material was evaluated as an interior surface material that could not be used to prepare an interior material with excellent trimming properties.

(Method of Evaluating Moldability)
(1) The interior surface material was left to stand in a heated high-temperature furnace (furnace temperature: 200° C.) for 30 seconds, and then the interior surface material was placed in a molding die and pressure molded. Thereafter, it was allowed to cool to room temperature to prepare the interior material.
(2) The state of the interior surface material during the above-mentioned molding process and the state of the molded interior material were visually confirmed, and the moldability was evaluated according to the following criteria.
◯: The interior surface material conformed to the molding die and could be molded to fit the internal shape of the molding die. Therefore, the interior surface material was evaluated as having excellent moldability.
×: The interior surface material had difficulty conforming to the molding die, and it was difficult to mold it to match the internal shape of the molding die. Therefore, the interior surface material was evaluated as having inferior moldability compared to interior surface materials evaluated as "○".

The results in Table 1 show that interior surface materials having a fiber sheet in which constituent fibers are integrated with each other by an adhesive component, and in which the average values of longitudinal tear strength and transverse tear strength per basis weight (average value A) after the heat treatment according to the present invention are less than 0.21, are interior surface materials that can provide interior materials with excellent trimming properties.

The following was found from the comparison between the comparative examples and the examples.
The results of comparing Comparative Examples 1 to 4 show that even if the fineness or fiber length of the fibers constituting the main skeleton of the fiber sheet constituting the interior surface material is changed, it does not necessarily result in an interior surface material that can provide an interior material with excellent trimmability.
From the results of comparing Comparative Example 1 with Comparative Example 5 and Example 4, it was found that even if the needle punching conditions were changed to make the entanglement state denser, it does not necessarily result in an interior surface material that can provide an interior material with excellent trimmability.
The results of comparing Comparative Example 4 with Comparative Example 6 and Example 1 show that even if the bonding and integration mode between the fibers that form the main skeleton of the fiber sheet that constitutes the interior surface material (or differences in bonding conditions) is changed, it does not necessarily result in an interior surface material that can provide an interior material with excellent trimmability.
From this, it was found that whether or not an interior surface material is capable of providing an interior material with excellent trimmability can be determined only by whether or not it satisfies the average values of longitudinal tear strength and transverse tear strength per basis weight specified in the present invention.

The results in Table 1 also show that if the average 20% modulus per unit area weight (average B) is less than 1.13, an interior surface material with superior moldability can be provided.

The interior surface material of the present invention has a superior feel and can therefore be suitably used for automobiles such as ceilings, door sides, pillar garnishes, and rear packages; interiors such as partitions; and building materials such as wall coverings.

Claims (1)

A surface material for interior use which is a fiber sheet having a thickness of 1.1 mm or more, in which constituent fibers having a fiber length of 25 mm or more and 76 mm or less are integrated with each other by an adhesive component (excluding those in which the constituent fibers are composed only of fibers made of polyester-based resin),
The constituent fibers of the fiber sheet are rayon fibers and polyester-based resin fibers,
After heat treatment under the following conditions, which are the measurement method, the average values of the longitudinal tear strength and transverse tear strength per basis weight are 0.18 (unit: N/(g/m ² )) or less;
The average value of the 20% modulus in the warp direction divided by the basis weight and the 20% modulus in the cross direction divided by the basis weight is less than 1.13.
Interior surface materials.
Note 1. The interior surface material was placed in a heat press device, and the interior surface material was sandwiched between an upper heating plate and a lower heating plate adjusted to a heating temperature of 200° C. and heated for 5 seconds. The gap distance between the upper heating plate and the lower heating plate during heating was 1.0 mm.
2. The interior surface material that had been subjected to the heat treatment was removed from the heat press device and placed in an atmosphere at room temperature (25° C.) to cool and then subjected to the heat treatment.