JP7853782B2 - Laminate and optical display member - Google Patents

Description

This invention relates to a laminate comprising a foam layer and an optical display member comprising the laminate.

Light-based display components in vehicles such as automobiles are undergoing significant development, driven by the need for safety indicators and improved aesthetics. With the increasing prevalence of autonomous driving, vehicle interiors are increasingly demanding greater comfort and livability. Therefore, from the perspective of comfort and personalization, development is progressing on interiors with seamless designs where lighting, displays, and sensors are activated only when necessary and blend seamlessly into the interior exterior when not in operation. Furthermore, development of active mood lighting linked to vehicle systems and sensors is also underway. Specifically, considerations include flashing red lights in the radius of blind spots for other road users, and linking lighting to seat retention, driver alerts, and drowsiness warnings.

Furthermore, from the perspective of luxury and design, various materials have been incorporated into interior materials. Beyond conventional leather-like materials, there has been a desire for the application of new flexible materials such as fabric, synthetic leather, and synthetic leather with perforation processing, including napped synthetic leather (suede). When active lighting or ambient lighting is combined with these fabrics or processed surfaces, glare (pointed light) can be perceived if light shines directly through the mesh or perforations of the fabric. This glare can impair the design of the interior material. Therefore, to prevent this glare, a vehicle interior material with a diffusion sheet laminated onto a fiber base material is known as prior art (see, for example, Patent Document 1). This makes it possible to further improve the design of vehicle interior materials. However, while the vehicle interior material described in Patent Document 1 can prevent glare, it was insufficient in terms of tactile feel.

As a vehicle interior component with improved surface texture, for example, a vehicle interior component in which a cushion layer made of foam is provided beneath the surface layer is known (see Patent Document 2). The cushion layer of the vehicle interior component described in Patent Document 2 has through-holes formed in the thickness direction, allowing light to pass through these through-holes.

Japanese Patent Publication No. 2021-79866 Japanese Patent Publication No. 2019-188919

However, as mentioned above, the vehicle interior material described in Patent Document 1, while able to prevent glare, was insufficient in terms of tactile feel. Furthermore, in the vehicle interior component described in Patent Document 2, the light from the light source directly reaches through the perforations in the cushion layer, making it difficult to prevent glare. Therefore, the vehicle interior component described in Patent Document 2 was insufficient in terms of design aesthetics. Thus, the object of the present invention is to provide a laminate that enables high design aesthetics through light and has a flexible tactile feel, and a light display component equipped with the laminate.

As a result of diligent research, the inventors of the present invention have found that a laminate comprising a skin layer having a predetermined total light transmittance and haze, and a foam layer having a predetermined total light transmittance and haze, can solve the above problems, and have completed the present invention.
The present invention is summarized in the following [1] to [15].
[1] A laminate comprising a light-transmitting epidermal layer and a foam layer, wherein the total light transmittance of the epidermal layer is 0.3% or more, the haze of the epidermal layer is 95% or less, the total light transmittance of the foam layer is 20% or more, and the haze of the foam layer is 95% or more.
[2] The laminate according to [1], wherein the epidermal layer has a plurality of openings.
[3] The laminate according to [1] or [2] above, wherein the total light transmittance is 0.1% or more, the haze is 96% or more, and the Asker C hardness is 70 or less.
[4] The laminate according to any one of [1] to [3] above, wherein the thickness of the foam layer is 0.5 mm or more and the foaming ratio of the foam layer is 5 times or more.
[5] The laminate according to any one of [1] to [4] above, wherein the foam layer is a crosslinked polyolefin foam layer.
[6] The laminate according to any one of [1] to [5] above, wherein the thickness of the epidermal layer is 0.2 to 2.0 mm.
[7] The laminate according to any one of [1] to [6] above, wherein the epidermal layer is made of cloth or a synthetic epidermis having multiple pores.
[8] The laminate according to [7], wherein the average pore diameter or the average length in the longitudinal direction of the pores of the synthetic surface having a plurality of pores is 3.0 mm or less.
[9] The laminate according to [7] or [8] above, wherein the synthetic surface comprises at least one elastic polymer selected from the group consisting of polyurethane resin, olefin-based thermoplastic elastomer, and vinyl chloride resin.
[10] The laminate according to [9] above, wherein the synthetic surface further comprises a base fabric.
[11] The laminate according to any one of [1] to [10], further comprising at least one of the printed layer and the printed film layer.
[12] The laminate according to [11], wherein the printed layer is formed by printing on the surface of at least one of the foam layer and the skin layer.
[13] A light display member comprising a laminate and a light source as described in any one of [1] to [12] above.
[14] The optical display member according to [13], comprising at least one electronic component of a sensor and a switch.
[15] The optical display member described in [13] or [14] above, which is a mobility interior component.

According to the present invention, it is possible to provide a laminate that enables the realization of high design quality through light and has a flexible tactile feel, as well as a light display member equipped with the laminate.

This is a cross-sectional view of one embodiment of the laminate of the present invention. This is a cross-sectional view of another embodiment of the laminate of the present invention. This is a cross-sectional view of another embodiment of the laminate of the present invention. This is a cross-sectional view of another embodiment of the laminate of the present invention. This is a cross-sectional view of another embodiment of the laminate of the present invention. This is a cross-sectional view of one embodiment of the optical display member of the present invention.

[Laminate]
The laminate of the present invention comprises a light-transmitting surface layer and a foam layer. By comprising a light-transmitting surface layer, the design of the optical display member comprising the laminate of the present invention can be improved. Furthermore, by comprising a foam layer, the laminate of the present invention can provide a flexible tactile feel to the optical display member comprising the laminate of the present invention. Moreover, by comprising a foam layer, the laminate of the present invention can provide weather resistance and waterproofing to the optical display member comprising the laminate of the present invention.

(epidermal layer)
The surface layer in the laminate of the present invention is light-transmitting. The light-transmitting properties of the surface layer can further improve the aesthetic design of the light display member. From the viewpoint of light transmittance, it is preferable that the surface layer has multiple openings. The surface layer allows light to pass through the multiple openings.
The materials constituting the surface layer are not particularly limited, but examples include polypropylene sheets, polyethylene sheets, olefin-based thermoplastic elastomer (TPO) sheets, polyvinyl chloride sheets, resin sheets such as mixed resin sheets of polyvinyl chloride and ABS resin, fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics using natural or artificial fibers, and synthetic surfaces such as artificial leather and synthetic leather. From the viewpoint of achieving high design quality, fabrics and synthetic surfaces are preferred as the surface layer among these materials. Furthermore, it is preferable that the synthetic surface has multiple holes (through holes) as openings. Since synthetic surfaces usually do not have openings, it is preferable that the synthetic surface is perforated.

<Total light transmittance>
The total light transmittance of the epidermal layer is 0.3% or higher. If the total light transmittance of the epidermal layer is less than 0.3%, the amount of light transmitted through the epidermal layer will be insufficient, and the effect of light to create a sense of luxury may be inadequate. From this viewpoint, the total light transmittance of the epidermal layer is preferably 0.5% or higher, and more preferably 1.0% or higher. There is no particular upper limit to the range of the total light transmittance of the epidermal layer, but the total light transmittance of the epidermal layer is usually 98% or lower, preferably 80% or lower. The total light transmittance of the epidermal layer can be controlled, for example, by adjusting the spacing between the warp and weft threads in the case of fabric, and by adjusting the size and number of pores in the case of synthetic epidermis. The total light transmittance of the epidermal layer can be measured by the method described in the examples below.

<Parallel light transmittance>
The parallel line transmittance of the epidermal layer is preferably 3% or less. When the parallel line transmittance of the epidermal layer is 3% or less, the epidermal layer can diffuse or block a certain amount of light, and can be sufficiently illuminated. From this viewpoint, the parallel line transmittance of the epidermal layer is more preferably 2% or less, and even more preferably 1% or less. The lower limit of the range of the parallel line transmittance of the epidermal layer is not particularly limited, but the parallel line transmittance of the epidermal layer is usually 0.01% or more. The parallel line transmittance of the epidermal layer can be controlled, for example, by adjusting the spacing between the warp and weft threads in the case of cloth, and by adjusting the size and number of pores in the case of synthetic epidermis. The parallel line transmittance of the epidermal layer can be measured by the method described in the examples below.

<Hayes>
The haze of the epidermal layer is 95% or less. If the haze of the epidermal layer is greater than 95%, the amount of light transmitted through the epidermal layer will be insufficient, and the effect of light to create a sense of luxury may be inadequate. From this viewpoint, the haze of the epidermal layer is preferably 92% or less, and more preferably 90% or less. The lower limit of the range of the haze of the epidermal layer is not particularly limited, but from the viewpoint of sufficiently creating an effect through light diffusion, the haze of the epidermal layer is, for example, 50% or more, preferably 60% or more. The haze of the epidermal layer can be controlled, for example, by adjusting the spacing between the warp and weft threads in the case of fabric, and by adjusting the size and number of pores in the case of synthetic epidermis. The haze of the epidermal layer can be measured by the method described in the examples below.

<Fabric Material>
The fabric constituting the epidermal layer may contain fibers derived from the trunk, stem, branches, leaves, roots, etc., of plants, or it may contain fibers that have been processed by heat treatment, drying treatment, crushing treatment, chemical treatment, etc. Such fibers may include linear fibers derived from kenaf, jute, Manila hemp, sisal, flax, ramie, ganpi, mitsumata, camellia, banana, pineapple, coconut, corn, sugarcane, bagasse, palm (oil palm, etc.), papyrus, reed, esparto, sabaigrass, tossa, wheat, rice, bamboo, coniferous trees (cedar, cypress, etc.), broad-leaved trees, kapok, cotton, etc.

Examples of fabrics include woven fabrics, Raschel lace, Raschel netting, braided fabrics, torsion lace, knotted netting, wool felt, needle-punched nonwoven fabrics, water-punched nonwoven fabrics, chemical nonwoven fabrics, and spunbond. From the viewpoint of design and light transmission through the opening, woven fabrics are preferred among these.

<Size of holes in the fabric>
In fabric, the gaps between the threads that make up the fabric act as openings that allow light to pass through. In the following explanation, the openings formed by adjacent threads will be called holes, the longest distance between each hole will be called the longitudinal length of the hole, and the average of these distances will be called the longitudinal length of the hole (hereinafter, the average longitudinal length of the hole). For example, if the fabric is a woven fabric made of warp and weft threads, the openings formed by adjacent warp threads and adjacent weft threads will be holes, and the longer of the distance between adjacent warp threads and the distance between adjacent weft threads will be the longitudinal length of the hole.
In the present invention, the average length of the holes in the fabric in the longitudinal direction is preferably 3.0 mm or less. When the average length of the holes in the longitudinal direction is 3.0 mm or less, it is possible to suppress the impairment of the design due to the holes. From this viewpoint, the average length of the holes in the longitudinal direction is more preferably 2.5 mm or less, and even more preferably 2.0 mm or less. Furthermore, from the viewpoint of enhancing the design with light emitted from the holes, the average length of the holes in the longitudinal direction is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.06 mm or more.

Furthermore, in the fabric, the average length of the holes in the short direction is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.06 mm or more, from the viewpoint of enhancing the design quality by the light emitted from the holes. From the viewpoint of preventing the design quality from being impaired due to the holes becoming too large in the fabric, the average length of the holes in the short direction is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.0 mm or less.
The length of the hole in the shorter direction is the shorter of the distance between adjacent warp threads and the distance between adjacent weft threads if the fabric is a woven material consisting of warp and weft threads, and the length in the direction perpendicular to the longitudinal direction if the fabric is not a woven material.
The size of the holes in the fabric can be measured by the method described in the examples below.

From the viewpoint of preventing the design from being impaired by large holes, the maximum length of the holes in the fabric in the longitudinal direction is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.0 mm or less. Furthermore, from the viewpoint of enhancing the design with light emitted from the holes, the maximum length of the holes in the longitudinal direction is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more.
From a similar viewpoint, the maximum length of the hole in the short direction is preferably 3.0 mm or less, more preferably 2.5 mm or less, and even more preferably 2.0 mm or less. From a similar viewpoint, the maximum length of the hole in the short direction is preferably 0.01 mm or more, more preferably 0.05 mm or more, and even more preferably 0.1 mm or more.
The size of the holes in the fabric can be measured by the method described in the embodiments below.

<Materials for synthetic skin>
The synthetic surface that constitutes the surface layer includes artificial leather and synthetic leather. Since a synthetic surface that is closer to the properties of natural leather can create a sense of luxury, it is preferable that the synthetic surface is made of synthetic leather. From the viewpoint of making the properties closer to those of natural leather, it is preferable that the synthetic surface contains at least one elastic polymer selected from the group consisting of polyurethane resin, olefin-based thermoplastic elastomer, and polyvinyl chloride resin.

Since natural leather is composed of collagen fibers, it is preferable that the synthetic surface further incorporates a base fabric to impart a similar soft feel to natural leather. Furthermore, from the viewpoint of imparting a similar soft feel to natural leather to the synthetic surface, the base fabric is preferably a nonwoven fabric with interwoven fibers using ultrafine fibers. In this case, the elastic polymer is filled between the nonwoven fabric fibers. Since natural leather does not contain a binder, it is preferable that the elastic polymer content in the artificial surface be low. Also, if there is no appropriate gap between the fibers and the elastic polymer, it may be difficult to impart flexible properties to the artificial surface.

<Size and shape of pores in synthetic epidermis>
As mentioned above, synthetic skins usually do not have openings, so it is preferable that the synthetic skin be perforated. The method of perforation is not limited in any way, but punching and laser melting are preferred. The shape of the holes in the synthetic skin is not particularly limited, but from the viewpoint of achieving high design quality and ease of processing, circular, elliptical, square, and rectangular shapes are preferred. When the shape of the holes is circular, the average hole diameter is preferably 5.0 mm or less. When the average hole diameter is 5.0 mm or less, it is possible to suppress the impairment of design quality due to the holes. From this viewpoint, the average hole diameter is more preferably 4.0 mm or less, and even more preferably 3.0 mm or less. Furthermore, from the viewpoint of enhancing design quality with light emitted from the holes, the average hole diameter is preferably 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more.
Furthermore, if the shape of the hole is not circular, from a similar viewpoint, the average length of the hole in the longitudinal direction is preferably 5.0 mm or less, more preferably 4.0 mm or less, and even more preferably 3.0 mm or less. Also from a similar viewpoint, the average length of the hole in the longitudinal direction is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more.
Furthermore, if the shape of the hole is not circular, from a similar viewpoint, the average length of the hole in the short direction is preferably 5.0 mm or less, more preferably 4.0 mm or less, and even more preferably 3.0 mm or less. Also from a similar viewpoint, the average length of the hole in the short direction is preferably 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more.
The size of the pores in the synthetic epidermis can be measured by the method described in the examples below.

From the viewpoint of preventing the design from being impaired by large holes, when the shape of the hole is circular, the maximum diameter of the hole is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. Furthermore, from the viewpoint of enhancing the design with light emitted from the hole, the maximum diameter of the hole is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more.
Furthermore, if the shape of the hole is not circular, from a similar viewpoint, the maximum length of the hole in the longitudinal direction is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. Furthermore, from a similar viewpoint, the maximum length of the hole in the longitudinal direction is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more.
Furthermore, if the shape of the hole is not circular, from a similar viewpoint, the maximum length of the hole in the short direction is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. Also from a similar viewpoint, the maximum length of the hole in the short direction is preferably 0.2 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more.
The size of the pores in the synthetic epidermis can be measured by the method described in the examples below.
In each hole, the longest distance is called the longitudinal length of the hole, and the short length of the hole is the length perpendicular to the longitudinal direction.

The number of pores per unit area in the synthetic surface is preferably 1 to 625 pores/ ^cm² . If the number of pores per unit area in the synthetic surface is 1 pore/ ^cm² or more, the light emitted from the pores can sufficiently enhance the appearance. On the other hand, if the number of pores per unit area in the synthetic surface is 625 pores/ ^cm² or less, it is possible to suppress the deterioration of the design due to too many light-emitting pores, or the reduction in the mechanical strength of the synthetic surface. From this viewpoint, the number of pores per unit area in the synthetic surface is more preferably 3 to 100 pores/ ^cm² , and even more preferably 6 to 25 pores/ ^cm² .

<Thickness>
The thickness of the epidermal layer is preferably 0.2 to 2.0 mm. If the thickness of the epidermal layer is 0.2 mm or more, it is possible to achieve an even higher level of design quality due to the epidermal layer. If the thickness of the epidermal layer is 2.0 mm or less, it is possible to suppress the interference of the flexibility of the laminate caused by the foam layer with the epidermal layer. From this viewpoint, the thickness of the epidermal layer is more preferably 0.25 to 1.5 mm, and even more preferably 0.3 to 1.0 mm.

<Color>
The epidermal layer may contain pigments such as carbon black, titanium dioxide, pearl particles, and metal powders such as aluminum powder, from the viewpoint of adjusting the color of the epidermal layer. The pigment content in the epidermal layer is preferably 0.01 to 3% by mass, and more preferably 0.02 to 1% by mass, based on the total amount of the epidermal layer.

(Foam layer)
<Total light transmittance>
The total light transmittance of the foam layer is 20% or more. If the total light transmittance of the foam layer is less than 20%, the amount of light transmitted through the foam layer will be insufficient, and the lighting effects may be inadequate. From this viewpoint, the total light transmittance of the foam layer is preferably 25% or more, and more preferably 30% or more. There is no particular upper limit to the range of the total light transmittance of the foam layer, but the total light transmittance of the foam layer is usually 80% or less, preferably 70% or less. The total light transmittance of the foam layer can be controlled by adjusting the material of the foam, the size of the bubbles in the foam, and the number of bubbles in the foam. The total light transmittance of the foam layer can be measured by the method described in the examples below.

<Parallel light transmittance>
The parallel-ray light transmittance of the foam layer is preferably 0.10% or higher. When the parallel-ray light transmittance of the foam layer is 0.10% or higher, the foam layer can diffuse or block a certain amount of light, allowing for sufficient illumination. Furthermore, the amount of light emitted from multiple openings can be made more uniform. From this viewpoint, the parallel-ray light transmittance of the foam layer is more preferably 0.15% or higher, and even more preferably 0.20% or higher. There is no particular upper limit to the range of the parallel-ray light transmittance of the foam layer, but the parallel-ray light transmittance of the foam layer is usually 7% or lower. The parallel-ray light transmittance of the foam layer can be measured by the method described in the examples below.

<Hayes>
The haze of the foam layer is 95% or more. If the haze of the foam layer is less than 95%, the shape of the light source may be recognizable, which may detract from the sense of luxury created by the light. Furthermore, if the haze of the foam layer is 95% or more, the light emitted from the light source becomes a softer light, which can further enhance the sense of luxury. In addition, the amount of light emitted from multiple openings can be made more uniform. From this viewpoint, the haze of the foam layer is preferably 96% or more, and more preferably 97% or more. There is no particular upper limit to the range of the haze of the foam layer, but the haze of the foam layer is usually 99.9% or less, and preferably 99.8% or less. The haze of the foam layer can be measured by the method described in the examples below.

<Thickness>
The thickness of the foam layer is preferably 0.5 mm or more. By making the foam layer thickness 0.5 mm or more, the laminate tends to have a more flexible feel. In addition, sufficient light resistance and waterproofness can be provided to the light display member. From this viewpoint, the thickness of the foam layer is more preferably 0.7 mm or more, and even more preferably 1.0 mm or more. Furthermore, the thickness of the foam layer is preferably 5 mm or less. By making the thickness of the foam layer 5 mm or less, it is easier to increase the total light transmittance of the laminate. From this viewpoint, the thickness of the foam layer is preferably 4 mm or less, and more preferably 3 mm or less.

<Expansion ratio>
The foaming ratio of the foam layer is not particularly limited, but is preferably 5 times or more. When the foaming ratio is 5 times or more, the laminate tends to become more flexible to the touch, and the total light transmittance of the foam layer also tends to be adjusted to the above range. From this viewpoint, the foaming ratio of the foam layer is more preferably 7 times or more, and even more preferably 10 times or more. Furthermore, the foaming ratio of the foam layer is preferably 40 times or less. By setting the foaming ratio of the foam layer to 40 times or less, the mechanical strength of the foam layer can be kept above a certain level. From this viewpoint, the foaming ratio of the foam layer is more preferably 35 times or less, and even more preferably 30 times or less.

<Closed cell ratio>
The foam constituting the foam layer may be open-cell foam or closed-cell foam. However, from the viewpoint of ensuring watertightness without the need for other layers and preventing water from penetrating from the surface layer into the inside of the foam, it is preferable that the foam constituting the foam layer be closed-cell foam. Note that closed-cell foam means that the ratio of closed cells to the total number of cells in the foam (called the closed-cell ratio) is 65% or more, while open-cell foam means that the closed-cell ratio is less than 65%.
The closed-cell ratio was measured according to the following procedure: A flat, square test piece with sides of 5 cm and a constant thickness was cut from a cross-linked polyolefin resin foam sheet. The thickness of the test piece was measured, and the apparent volume V1 of the test piece was calculated, along with the weight W1 of the test piece. Next, the apparent volume V2 occupied by the cells was calculated based on the following formula. The density of the resin constituting the test piece was assumed to be 1 g/ ^cm³ .
The apparent volume occupied by the bubble is V2 = V1 - W1
Next, the test specimen is submerged in 23°C distilled water to a depth of 100 mm from the surface, and a pressure of 15 kPa is applied to the specimen for 3 minutes. After this, the test specimen is removed from the water, any moisture adhering to the surface of the specimen is removed, the weight W2 of the specimen is measured, and the open-cell ratio F1 and closed-cell ratio F2 are calculated based on the following formulas.
Open cell ratio F1 (%) = 100 × (W2 - W1) / V2
Closed-cell ratio F2 (%) = 100 - F1
From the viewpoint of ensuring watertightness without the need for other layers and preventing water from penetrating from the surface layer into the inside of the foam, the closed-cell ratio of the foam layer is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The upper limit of the closed-cell ratio range for the foam layer is 100%.

<Color>
The foam layer may be colored with a colorant. In this case, it is preferable that the foam layer be colored to a color similar to or the same color as the epidermal layer. Examples of colors for the foam layer include white, black, gray, red, and blue. Examples of colorants for coloring the foam layer include titanium dioxide, carbon black, quinacridone-based red pigment, and phthalocyanine blue. The colorant content in the foam layer is preferably 0.01 to 3.0% by mass, and more preferably 0.05 to 0.5% by mass, based on the total amount of the foam layer.

<Materials>
The foam layer is preferably formed of a resin, specifically a polyolefin-based foam layer, a urethane-based foam layer, an acrylic-based foam layer, and among these, a polyolefin-based foam layer is preferred. The polyolefin-based foam layer is formed by foaming a foamable resin composition containing a polyolefin resin. Examples of polyolefin resins include polypropylene resin, polyethylene resin, and ethylene-vinyl acetate copolymer, which may be used individually or in combination of two or more.
It is preferable that only one type of resin is used to form the foam layer. By using only one type, clouding caused by blending is less likely to occur, and the light transmittance of the foam layer can be improved.
The foam layer may be a single foam layer or a multilayer foam layer formed by stacking two or more foams. The individual foams constituting the multilayer foam layer may have different physical properties such as composition, thickness, total light transmittance, foaming ratio, and degree of crosslinking, and it is preferable that the multilayer foam layer as a whole satisfies the above physical properties.

When the foam layer is a polyolefin-based foam layer, it is preferable that the foam layer is a crosslinked polyolefin-based foam layer (crosslinked polyolefin-based foam layer). One method for crosslinking the foam layer is to irradiate the foam sheet with ionizing radiation such as electron beams, alpha rays, beta rays, and gamma rays. Among these ionizing radiations, it is more preferable that the foam layer is crosslinked by electron beams. Details of electron beam crosslinking will be explained later in the description of the foam layer manufacturing method.

Polyethylene resin
Examples of polyethylene resins include low-density polyethylene resin (0.93 g/ ^cm³ or less, LDPE), medium-density polyethylene resin (greater than 0.930 g/ ^cm³ and less than 0.942 g/ ^cm³ , MDPE), and high-density polyethylene resin (0.942 g/ ^cm³ or more, HDPE). A suitable specific example of low-density polyethylene resin is linear low-density polyethylene resin (LLDPE).

The polyethylene resin may be an ethylene homopolymer, or it may be a copolymer of ethylene and a small amount of α-olefin, with ethylene as the main component (preferably 75% by mass or more, more preferably 90% by mass or more of the total monomer). α-olefins preferably have 3 to 12 carbon atoms, more preferably 4 to 10 carbon atoms, and specifically include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, etc. In the copolymer, these α-olefins can be used individually or in combination of two or more.
Furthermore, polyethylene resin may be used alone or in combination of two or more types.

≪Polypropylene resin≫
Examples of polypropylene resins include homopolypropylene, which is a homopolymer of propylene, and copolymers of propylene with a small amount of ethylene and α-olefins other than propylene, where propylene is the main component (preferably 75% by mass or more, more preferably 90% by mass or more of the total monomers).
Examples of copolymers of propylene with ethylene and α-olefins other than propylene include block copolymers (block polypropylene), random copolymers (random polypropylene), and random block copolymers.
Examples of α-olefins other than propylene include α-olefins with approximately 4 to 10 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene. Among these, ethylene is preferred from the viewpoint of moldability and heat resistance. In copolymers, these α-olefins can be used individually or in combination of two or more.
Furthermore, polypropylene resin may be used alone or in combination of two or more types.

In this invention, polyethylene resin, polypropylene resin, or a mixture thereof, polymerized with polymerization catalysts such as Ziegler-Natta compounds, metallocene compounds, or chromium oxide compounds may be used.

Ethylene-vinyl acetate copolymer
Examples of ethylene-vinyl acetate copolymers used as polyolefin resins include those containing 50% by mass or more of ethylene-derived structural units. Since ethylene-vinyl acetate copolymers have high compatibility with polyethylene resins and polypropylene resins, they can also be used in combination with one or more selected from polyethylene resins and polypropylene resins.
The density of the ethylene-vinyl acetate copolymer is preferably 0.92 g/ ^cm³ or more, more preferably 0.93 g/ ^cm³ or more, even more preferably 0.94 g/ ^cm³ or more, and preferably 0.97 g/ ^cm³ or less, more preferably 0.96 g/ ^cm³ or less.

The polyolefin foam layer may consist solely of the polyolefin resin described above, or it may be a mixture of the polyolefin resin and an elastomer. Examples of elastomers include ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), and styrene rubber. Thermoplastic elastomers are also available. Examples of thermoplastic elastomers include olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers.
The polyolefin resin content in the polyolefin foam layer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the foam layer.

<Degree of cross-linking (gel fraction)>
The degree of crosslinking (gel fraction) of the polyolefin foam layer is preferably 5 to 60% by mass. If the gel fraction is above the lower limit, sufficient crosslinking is formed in the foam layer, which tends to increase the mechanical strength. If the degree of crosslinking is below these upper limits, it is easier to ensure a flexible feel. From this viewpoint, a degree of crosslinking of 10 to 50% by mass is more preferable, and 10 to 40% by mass is even more preferable. The degree of crosslinking can be measured by the measurement method described later.

(Manufacturing of the foam layer)
The foam layer is formed by foaming a foamable resin composition. Foaming methods include using a thermal decomposition type foaming agent, a foaming agent such as water, or a foaming method using an inert gas such as carbon dioxide or butane gas, as will be described later.

(Manufacturing of polyolefin-based foam layer)
The polyolefin-based foam layer is produced, for example, by foaming a foamable resin composition containing the polyolefin resin and a foaming agent as described above. Examples of foaming agents include chemical foaming agents and physical foaming agents.

<Foaming agent>
As a chemical blowing agent, a pyrolysis-type blowing agent is preferred. As pyrolysis-type blowing agents, organic blowing agents and inorganic blowing agents can be used. Examples of organic blowing agents include azodicarbonamide, azodicarboxylic acid metal salts (such as barium azodicarboxylic acid), azobisisobutyronitrile and other azo compounds, nitroso compounds such as N,N'-dinitrosopentamethylenetetramine, hydrazodicarbonamide, hydrazine derivatives such as 4,4'-oxybis(benzenesulfonyl hydrazide) and toluenesulfonyl hydrazide, and semicarbazide compounds such as toluenesulfonyl semicarbazide.
Examples of inorganic blowing agents include ammonium carbonate, sodium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, and anhydrous monosodium citrate.
Among these, azo compounds are preferred from the viewpoint of obtaining fine bubbles, as well as from the viewpoints of economy and safety, and azodicarbonamides are more preferred.
A single type of thermal decomposition foaming agent may be used alone, or two or more types may be used in combination.
Examples of physical foaming agents include inert gases, which will be discussed later.

The amount of foaming agent in the foamed resin composition is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and even more preferably 2 to 20 parts by mass, per 100 parts by mass of polyolefin resin. By adding 1 part by mass or more of the foaming agent, the foam layer is appropriately foamed, allowing for a certain degree of flexibility. Furthermore, by adding 30 parts by mass or less of the foaming agent, excessive foaming of the foam layer is prevented, resulting in improved mechanical strength and other properties of the foam layer.

<Nucleating agent>
The foaming lipid composition may contain a nucleating agent. The nucleating agent is not particularly limited as long as it has the effect of improving the rate of crystal nucleation. Adding a nucleating agent to polyolefin resins such as polyethylene resin or polypropylene resin can reduce the size of the resulting crystals, thereby improving the transparency of the foam layer.
Examples of nucleating agents include substances that improve the rate of crystal nucleation by promoting molecular chain orientation through the adsorption process of polymer molecular chains.
More specifically, examples include high-melting-point polymers, organic carboxylic acids or their metal salts, aliphatic alcohols, dibenzylidene sorbitol or its derivatives, rosin acid partial metal salts, amide compounds, inorganic fine particles, organophosphate compounds or their metal salts, imides, quinacridones, quinones, aromatic sulfonates or their metal salts, sugars, and mixtures thereof. These may be used individually or in combination of two or more.

<Additives>
The foamed resin composition may contain components such as crosslinking aids, decomposition temperature regulators, and antioxidants.
A polyfunctional monomer can be used as a crosslinking aid. By adding the crosslinking aid to the polyolefin resin, the electron dose irradiated in step (2) described later is reduced, thereby preventing the severance and degradation of resin molecules associated with electron beam irradiation.
Specific examples of crosslinking aids include compounds with three functional groups in one molecule, such as trimethylolpropane trimethacrylate, trimellilic acid trialyl ester, 1,2,4-benzenetricarboxylic acid trialyl ester, and triallyl isocyanurate; compounds with two functional groups in one molecule, such as 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, and divinylbenzene; and diallyl phthalate, diallyl terephthalate, diallyl isophthalate, ethylvinylbenzene, neopentyl glycol dimethacrylate, lauryl methacrylate, and stearyl methacrylate.
These crosslinking agents can be used individually or in combination of two or more.

The amount of crosslinking aid added is preferably 0.5 to 10 parts by mass, more preferably 1.0 to 8 parts by mass, and even more preferably 1.5 to 5 parts by mass, per 100 parts by mass of polyolefin resin. By adding 0.5 parts by mass or more, it is possible to stably obtain the desired degree of crosslinking in the foam layer, and by adding 10 parts by mass or less, it becomes easier to control the degree of crosslinking in the foam layer.

The foamed resin composition may contain a decomposition temperature regulator. The decomposition temperature regulator is added to lower the decomposition temperature of the thermal decomposition foaming agent or to accelerate the decomposition rate. Specific examples of such compounds include zinc oxide, zinc stearate, and urea. The decomposition temperature regulator is added, for example, in an amount of 0.01 to 5 parts by mass per 100 parts by mass of polyolefin resin, to adjust the surface condition of the foam layer.

The foamed resin composition may contain antioxidants. Examples of antioxidants include phenolic antioxidants such as 2,6-di-t-butyl-p-cresol and pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], sulfur-based antioxidants such as dilauryl thiodipropionate, phosphorus-based antioxidants, and amine-based antioxidants. The antioxidant is added in an amount of, for example, 0.01 to 5 parts by mass per 100 parts by mass of the polyolefin resin.
In addition to these, the foamed resin composition may also contain additives commonly used in foams, such as heat stabilizers, colorants, flame retardants, antistatic agents, and fillers.

(Manufacturing process for polyolefin foam layer)
There are no particular limitations on the method for producing the polyolefin foam layer, but it can be produced by heating a foamable sheet made of a foamable resin composition containing at least a polyolefin resin and a thermal decomposition type blowing agent to foam the thermal decomposition type blowing agent. More specifically, the production method preferably includes the following steps (1) to (3).
Step (1): A step of molding a foamed sheet made of a foamed resin composition containing at least a polyolefin resin and a pyrolysis-type foaming agent. Step (2): A step of crosslinking the foamed sheet by irradiating it with an electron beam. Step (3): A step of heating the crosslinked foamed sheet to foam the pyrolysis-type foaming agent and obtain a foamed layer.

In step (1), the method for forming the foamed sheet is not particularly limited, but for example, a polyolefin resin, a pyrolysis-type foaming agent, a nucleating agent (if necessary), and additives may be supplied to an extruder, melted and kneaded, and the foamed resin composition may be extruded from the extruder into a sheet. Alternatively, the foam layer may be formed by pressing the foamed resin composition or the like.
The molding temperature of the foamed resin composition (i.e., the temperature during extrusion or pressing) is preferably 50°C to 250°C, and more preferably 80°C to 180°C.

In step (2), the method for crosslinking the foamed sheet is to irradiate the foamed sheet with an electron beam. The electron beam irradiation dose should be adjusted so that the degree of crosslinking of the resulting foam layer falls within the desired range described above, but it is preferably 1 to 9 Mrad, and more preferably 1.9 to 5 Mrad.

In step (3), the heating temperature when heating the foaming sheet to foam the pyrolysis-type foaming agent should be at or above the foaming temperature of the pyrolysis-type foaming agent, but preferably 200 to 300°C, more preferably 220 to 280°C.

Furthermore, in this manufacturing method, the foamed sheet may be stretched in either the medium-density (MD) or the tectonic (TD) direction, or both. The stretching of the foamed sheet may be performed after foaming to obtain a foamed layer, or it may be performed while foaming the foamed sheet. When stretching the foamed layer after foaming to obtain a foamed layer, the foamed layer may be stretched continuously while maintaining the molten state from the foaming stage without cooling, or the foamed layer may be cooled, then heated again to a molten or softened state before stretching. Stretching makes it easier to make the foamed layer thinner. Also, during stretching, the foamed layer should be heated to, for example, 100 to 280°C, preferably 150 to 260°C. In this invention, stretching increases the bubble diameter of the foam along either the MD or TD direction, or both, which tends to increase light transmittance.

However, in steps (1) to (3) above, instead of irradiating with an electron beam, crosslinking may be performed by pre-mixing an organic peroxide into the polyolefin resin composition and then heating the foamed sheet to decompose the organic peroxide.

The method for producing the polyolefin foam layer is not limited to the method of performing steps (1) to (3) above, but may also be foamed by physical foaming.
When foaming is induced by physical foaming, it is preferable to impregnate the resin composition containing polyolefin resin, a nucleating agent as needed, and additives with a physical foaming agent. It is preferable to impregnate the resin composition with the physical foaming agent after it has been formed into a sheet. Alternatively, the resin composition may be formed into a sheet, irradiated with an electron beam, and then impregnated with the physical foaming agent. Electron beam irradiation can be performed using the same method as in step (2) above.
It is preferable to use a high-pressure inert gas as the physical blowing agent. The inert gas is not particularly limited as long as it is inert to the resin composition and can impregnate it, and examples include carbon dioxide, butane gas, nitrogen gas, and air. These gases may be used in mixtures. Of these, carbon dioxide and butane gas are preferred from the viewpoint of easily increasing the foaming ratio of the foam layer. It is preferable that the inert gas used for impregnation be in a supercritical or subcritical state.

(Printed layer, printed film layer)
The laminate of the present invention may comprise at least one of a printed layer and a printed film layer. This allows the shape corresponding to the printed pattern to be perceived from the surface layer side by light. The printed layer can be formed, for example, by printing on the surface of at least one of the foam layer and the surface layer. The printed film layer is formed by forming a printed layer on a base film such as a polyolefin film or a polyester film such as a PET film. Known methods such as inkjet printing can be used as appropriate for forming the printed layer. The thickness of the printed layer is preferably 1 to 25 μm, more preferably 2 to 10 μm. The thickness of the printed film layer is preferably 4 to 50 μm, more preferably 12 to 25 μm.

(Adhesive layer)
The laminate of the present invention may have an adhesive layer. Preferably, the adhesive layer is provided between the skin layer and the foam layer. By providing an adhesive layer between the skin layer and the foam layer, the skin layer and the foam layer can be easily integrated. Furthermore, by using an adhesive layer, the adhesive layer functions as a waterproof layer, and the waterproofness of the laminate can be ensured even if the foam constituting the foam layer is an open-cell foam.
The adhesive layer may be an adhesive layer composed of an adhesive sheet or the like, or it may be a resin sheet. Examples of resin sheets include thermoplastic resin sheets and hot melt films.
Furthermore, the printed film layer described above may be used as an adhesive layer.
The adhesive layer may be formed with an adhesive other than an adhesive, but an adhesive layer formed with an adhesive is preferred. Known adhesives can be used for the adhesive layer, including acrylic adhesives, urethane adhesives, silicone adhesives, and rubber adhesives.

The total light transmittance of the adhesive layer is, for example, 70% or more, preferably 80% or more, and more preferably 90% or more, from the viewpoint of not impairing the design quality achieved by the epidermal layer and foam layer. The upper limit of the range of total light transmittance is not particularly limited and may be 100%. Also, the parallel line transmittance is, for example, 70% or more, preferably 80% or more, and more preferably 90% or more. The upper limit of the range of parallel line transmittance is not particularly limited and may be 100%.
The thickness of the adhesive layer is preferably 15 to 500 μm. If the thickness of the adhesive layer is 15 μm or more, the surface layer and the foam layer can be bonded more firmly. If the thickness of the adhesive layer is 500 μm or less, the obstruction of light transmission of the laminate by the adhesive layer can be suppressed. From this viewpoint, the thickness of the adhesive layer is more preferably 20 to 200 μm, and even more preferably 25 to 150 μm.
The adhesive layer may be colored with pigments or dyes. The pigments, dyes, colors, and quantities used are as described above for the foam layer.

(Other layers)
The laminate of the present invention may further comprise layers other than those described above, as long as the effects of the present invention are not impaired.

(Laminate)
<Total light transmittance>
The total light transmittance of the laminate is preferably 0.1% or higher. When the total light transmittance of the laminate is 0.1% or higher, sufficient light can be transmitted through the laminate, allowing for sufficient lighting effects. From this viewpoint, the total light transmittance of the laminate is more preferably 0.3% or higher, and even more preferably 1.5% or higher. There is no particular upper limit to the range of the total light transmittance of the laminate, but the total light transmittance of the laminate is usually 30% or less, preferably 20% or less. The total light transmittance of the laminate can be controlled by adjusting the total light transmittance of the skin layer and the total light transmittance of the foam layer. The total light transmittance of the laminate can be measured by the method described in the examples below.

<Parallel light transmittance>
The parallel-ray light transmittance of the laminate is preferably 0.01% or higher. When the parallel-ray light transmittance of the laminate is 0.01% or higher, the laminate can diffuse or block a certain amount of light, and can be sufficiently illuminated. There is no particular upper limit to the range of the parallel-ray light transmittance of the laminate, but the parallel-ray light transmittance of the laminate is usually 3% or less. The parallel-ray light transmittance of the laminate can be controlled by adjusting the parallel-ray light transmittance of the surface layer and the parallel-ray light transmittance of the foam layer. The parallel-ray light transmittance of the laminate can be measured by the method described in the examples below.

<Hayes>
The haze of the laminate is preferably 96.0% or higher. When the haze of the laminate is 96.0% or higher, the light emitted from the light source becomes a soft light, which can further effectively create a sense of luxury. It also prevents the shape of the light source from being recognized, which would detract from the sense of luxury created by the light. Furthermore, it can suppress unevenness in brightness in the laminate. From this viewpoint, the haze of the laminate is more preferably 97.0% or higher, and even more preferably 98.0% or higher. There is no particular upper limit to the range of the haze of the laminate, but the haze of the laminate is usually 99.9% or lower. The haze of the laminate can be controlled by adjusting the haze of the surface layer and the haze of the foam layer. The haze of the laminate can be measured by the method described in the examples below.

<Asker C hardness scale>
The Asker C hardness of the laminate is preferably 70 or less. A Asker C hardness of 70 or less provides the laminate with a sufficiently flexible feel. From this viewpoint, the Asker C hardness of the laminate is more preferably 65 or less, even more preferably 60 or less, and even more preferably 55 or less. While there is no particular lower limit to the Asker C hardness, from the viewpoint of maintaining a certain level of mechanical strength, the Asker C hardness of the laminate is preferably 5 or more, and more preferably 10 or more. The Asker C hardness of the laminate can be adjusted by the thickness of the foam layer, the foaming ratio, etc. The Asker C strength of the laminate can be measured by the method described in the examples below.

(Manufacturing of laminates)
The laminate of the present invention can be manufactured, for example, by laminating a foam layer, a skin layer, and a printed film layer, which may be provided as needed. The foam layer may be one on which the printed layer has been formed. Lamination may be carried out by a thermal lamination method, or the layers may be bonded together with a bonding agent or adhesive.

(Laminated structure)
The laminate of the present invention may be a laminate 1A comprising a skin layer 10 and a foam layer 20, as shown in Figure 1. Alternatively, a printed layer 30 may be further provided on the side of the foam layer 20 opposite to the skin layer, as shown in the laminate 1B in Figure 2. Furthermore, a printed layer 30 may be further provided between the skin layer 10 and the foam layer 20, as shown in the laminate 1C in Figure 3. The printed layer 30 may be formed by printing on the foam layer 20 or by printing on the skin layer 10. Alternatively, a printed film layer 40 may be further provided on the side of the foam layer 20 opposite to the skin layer, as shown in the laminate 1D in Figure 4. Furthermore, a printed film layer 40 may be further provided between the skin layer 10 and the foam layer 20, as shown in the laminate 1E in Figure 5.

Here, although each of the above layers may be laminated directly, it is preferable that each of the above layers be laminated via an adhesive layer (not shown). For example, in the configurations of Figures 1, 2, and 4, it is preferable that an adhesive layer is provided between the foam layer 20 and the surface layer 10, and that the foam layer 20 and the surface layer 10 are bonded via the adhesive layer. Also, in the configuration of Figure 3, it is preferable that an adhesive layer is provided between the surface layer 10, which has a printed layer 30, and the foam layer 20, and that these are bonded via the adhesive layer. Alternatively, it is preferable that an adhesive layer is provided between the foam layer 20, which has a printed layer 30, and the surface layer 10, and that these are bonded via the adhesive layer.
Furthermore, in the configuration shown in Figure 5, the printed film layer 40 may also serve as an adhesive layer, or adhesive layers may be provided between the printed film layer 40 and the surface layer 10, between the printed film layer 40 and the foam layer 20, or both thereof, so that each layer is bonded together by the adhesive layer.

[Optical display component]
The laminate of the present invention can be suitably used as an optical display member. The optical display member of the present invention comprises the laminate of the present invention and a light source. The configuration of the optical display member is not particularly limited, but for example, as shown in Figure 6, it can be an optical display member in which a light source 50 is laminated on a laminate 1. Here, the laminate 1 and the light source 50 may be laminated directly, but it is preferable that the laminate 1 and the light source 50 are laminated via a bonding material or adhesive (not shown). The bonding material and adhesive may be a thermoplastic resin, a thermosetting resin, a hot melt film, or an adhesive. Examples of light sources include liquid crystal displays (LCDs) and light-emitting diodes (LEDs).

The light display component may be equipped with sensors. Examples of sensors include electrostatic sensors, pressure sensors, hover sensors, heat sensors, and vibration sensors. For example, by providing electrostatic and pressure sensors on the light display component, touch input can be enabled. This allows, for example, light effects to be activated by touching the light display component. Furthermore, by providing an electrostatic sensor on the light display component, it is possible to detect when a person approaches the light display component. This allows, for example, light effects to be activated when a person approaches the light display component. By providing a hover sensor on the light display component, non-contact input can be enabled. This allows, for example, light effects to be activated by bringing a hand close to the light display component. By providing a heat sensor on the light display component, light effects can be activated according to the room temperature, for example, according to the season. It is also possible to activate light effects to draw attention when the room temperature is too high or too low. By providing a vibration sensor on the light display component, theft of mobility can be prevented. For example, if a vibration sensor detects vibration while a mobility device is parked, it can activate a light to alert those nearby of theft. The light display component may also include a switch. Examples of switches include mechanical switches and membrane switches. By providing such a switch in the light display device, the light display can be started and stopped using the switch. Furthermore, the light display component may include both a sensor and a switch.

In the optical display member, the sensor may be placed between the foam layer and the surface layer, or between the foam layer and the light source. The sensor is preferably a sheet-like component (sensor sheet) to facilitate placement in the laminate. The switch may also be placed between the foam layer and the surface layer, or between the foam layer and the light source. However, if the light source is provided on the back side of the switch, light from the light source will transmit through it, allowing switch information such as switch position information and information related to switch operation (up/down switch display, selection switch display, keyboard-like switch display, etc.) to be displayed. In other words, by placing the switch in a position illuminated by light from the light source, the operator can be accurately shown the switch position. Furthermore, the switch information can also be displayed on the surface of the optical display member using the aforementioned printed layer or printed film layer.

This light-displaying member is suitably used as a mobility interior component in mobility devices such as automobiles, flying cars, airplanes, and ships. Furthermore, this mobility interior component exhibits excellent design qualities through the laminate of the present invention and the light leaking from the openings in the surface layer.

The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

The evaluation method is as follows:
<Total light transmittance, parallel line transmittance, and haze>
Total light transmittance, parallel light transmittance, and haze were measured in accordance with ASTM D1003 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH4000").

<Size of the pores>
When observing the epidermal layer from a direction perpendicular to it, the opening was defined as a hole. If the shape of the hole was not circular, the length in the longitudinal direction and the length in the transverse direction were measured. If the shape of the hole was circular, the average hole diameter was measured. Specifically, if the shape of the hole was not circular, 10 arbitrary holes were measured to determine the average length in the longitudinal direction, the average length in the transverse direction, the maximum length in the longitudinal direction, and the maximum length in the transverse direction. If the shape of the hole was circular, 10 arbitrary holes were measured to determine the average hole diameter. Note that when holes in the epidermal layer are formed by perforation processing, the size of the holes is almost constant, so the maximum length and maximum hole diameter are approximately the same as the average length and average hole diameter, respectively.

<Expansion ratio>
The expansion ratio was calculated by determining the density (apparent density) of the foam layer and then calculating the reciprocal of that density. The apparent density was measured in accordance with JIS K7222:2005.

<Asker C hardness scale>
An Asker rubber hardness tester Type C (manufactured by Polymer Instruments Co., Ltd.) was used to measure the hardness by placing the tester's indenter against the surface layer of the laminate. The measurement was performed at 25°C.

<Gel fraction (degree of crosslinking)>
A test specimen of approximately 100 mg was taken from the foam layer, and its weight A (mg) was accurately weighed. Next, this test specimen was immersed in 30 ^cm³ of xylene at 120°C and left for 24 hours. Then, it was filtered through a 200-mesh wire mesh, and the insoluble matter on the mesh was collected, vacuum-dried, and the weight B (mg) of the insoluble matter was accurately weighed. From the obtained value, the degree of crosslinking (mass %) was calculated using the following formula.
Degree of crosslinking (mass%) = (B/A) x 100

<Closed cell ratio>
The closed-cell ratio of the foam layer was measured using the method described in the section on the closed-cell ratio of the foam layer above.

<Evaluation of glare (point light)>
The laminate was placed horizontally with the foam layer facing downwards. A 20mm diameter pen-type light (manufactured by ESCO Corporation, product name "EA758RK-4") was used to illuminate the laminate from below. The laminate was observed from a vertical direction above the illuminated laminate, and glare (point light) was evaluated as follows.
○...Because the light was diffused, the range of light emitted by the pen-type light could not be determined.
×...The range of light emitted by the pen-type light was recognized.

<Evaluation of Light Contours>
The laminate was placed horizontally with the foam layer facing downwards. A 20mm diameter pen-type light (manufactured by ESCO Corporation, product name "EA758RK-4") was used to illuminate the laminate from below. The laminate was observed from above, perpendicular to the illuminated laminate, and the outline of the pen-type light was evaluated as follows.
○...The outline of the pen-shaped light could not be recognized.
×...The outline of the pen-shaped light was recognized.

<Materials used in the foam layer>
The materials used in the examples and comparative examples are as follows:
Fabric: Manufactured by Shincol Co., Ltd., product name "ML3332 Anowar", warp threads: 100% polyester, weft threads: 100% polyethylene.
Foam: Manufactured by Sekisui Chemical Co., Ltd., product name "VSW2002", cross-linked polyolefin closed-cell foam, double-sided corona treated.

Furthermore, the synthetic epidermis used in the examples was prepared as follows.
80 parts by mass of olefin-based thermoplastic elastomer (TPO), 10 parts by mass of propylene-based random copolymer (rPP), 10 parts by mass of linear low-density polyethylene (LLDPE), and 0.2 parts by mass of pigment masterbatch (manufactured by Tokyo Ink Co., Ltd., product name "PEX99901") were put into an extruder and melt-kneaded to obtain a resin composition. Then, a synthetic surface with a thickness of 0.50 mm was produced by extruding the resin composition into a sheet.
Next, circular pores with a diameter of approximately 300 μm were formed in the synthetic surface by perforation processing, such that the number of pores per unit area was 20 pores/ ^cm² .
The raw materials used to produce the synthetic epidermis were as follows:
Olefin-based thermoplastic elastomer (TPO): Manufactured by Mitsui Chemicals, Inc., product name "8030N"
Propylene-based random copolymer (rPP): Manufactured by Prime Polymer Co., Ltd., trade name "E-333GV"
Linear low-density polyethylene (LLDPE): Manufactured by Prime Polymer Co., Ltd., product name "20100J"
Pigment masterbatch: Manufactured by Tokyo Ink Co., Ltd., product name "PEX99901", containing 40% by mass of pigment (carbon black).

(Example 1)
The fabric and foam were laminated together via a 100 μm thick adhesive sheet (manufactured by Sekisui Chemical Co., Ltd., product name "LSP02", total light transmittance 87%, parallel light transmittance 79%) to obtain the laminate of Example 1.
Each of the obtained laminates was evaluated, and the results are shown in Table 1.

(Example 2)
A laminate of Example 2 was obtained by laminating a porosity-formed synthetic surface and a foam material via a 0.5 mm thick adhesive sheet (manufactured by Sekisui Chemical Co., Ltd., product name "LSP02").
Each of the obtained laminates was evaluated, and the results are shown in Table 1.

(Comparative Example 1)
As Comparative Example 1, each evaluation was performed on fabric only, and the results are shown in Table 1.

The Asker C hardness test results showed that the laminates of Examples 1 and 2 possessed a flexible tactile feel. Furthermore, the glare (point illumination) and light contour evaluation results were favorable. On the other hand, Comparative Example 1, based on the Asker C hardness test results, lacked a flexible tactile feel. Furthermore, Comparative Example 1 performed poorly in both glare (point illumination) and light contour evaluation.

1, 1A-1E Laminate 2 Light display component 10 Surface layer 20 Foam layer 30 Printed layer 40 Printed film layer 50 Light source

Claims (13)

A laminate comprising a light-transmitting epidermal layer and a foam layer,
The total light transmittance of the epidermal layer is 0.3% or more.
The haze of the epidermal layer is 95% or less.
The total light transmittance of the foam layer is 20% or more.
The haze of the aforementioned foam layer is 95% or more.
The aforementioned foam layer is a cross-linked polyolefin foam layer.
The aforementioned epidermal layer is a laminate made of cloth or a synthetic epidermis having multiple pores . The laminate according to claim 1, wherein the surface layer has a plurality of openings. The laminate according to claim 1 or 2, wherein the total light transmittance is 0.1% or more, the haze is 96% or more, and the Asker C hardness is 70 or less. The thickness of the foam layer is 0.5 mm or more.
The laminate according to any one of claims 1 to 3, wherein the foaming ratio of the foam layer is 5 times or more. The laminate according to any one of claims 1 to 4, wherein the thickness of the surface layer is 0.2 to 2.0 mm. The laminate according to any one of claims 1 to 5, wherein the average pore diameter or the average length in the longitudinal direction of the pores in the synthetic surface having the plurality of pores is 3.0 mm or less. The laminate according to any one of claims 1 to 6 , wherein the synthetic surface comprises at least one elastic polymer selected from the group consisting of polyurethane resin, olefin-based thermoplastic elastomer, and polyvinyl chloride resin. The laminate according to claim 7 , wherein the synthetic surface further comprises a base fabric. The laminate according to any one of claims 1 to 8 , further comprising at least one of the printed layer and the printed film layer. The laminate according to claim 9 , wherein the printed layer is formed by printing on the surface of at least one of the foam layer and the skin layer. A light display member comprising a laminate and a light source according to any one of claims 1 to 10 . The optical display member according to claim 11 , comprising at least one electronic component of a sensor and a switch. The optical display member according to claim 11 or 12 , which is a mobility interior component.