JP7165078B2 - Light-transmitting sheets, multilayer sheets, lighting devices, automobile interior materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a light-transmitting sheet, a multilayer sheet using the same, a lighting device, and an automobile interior member.

Various levels of softness and various functions are required for skin materials that cover the surfaces of hard machinery such as passenger cars and other automobiles, furniture, indoor interiors, and even robots. For example, as an interior skin material for automobiles, it has heat resistance, weather resistance, cold resistance, texture retention including heat history during molding, scratch resistance against human contact (scratch abrasion resistance), and human accompaniment. Oil resistance and chemical resistance to chemical substances are required. In recent years, with the diversification of consumer tastes, light-transmitting artificial leather sheets have been developed.

A light-transmitting artificial leather sheet has a leather-like appearance and feel, and can be backlit to create a design that combines letters, figures, and patterns (see, for example, Patent Document 1). .

JP 2016-81817 A

However, the artificial leather sheet of Patent Document 1 cannot be said to have sufficiently high scratch resistance, heat resistance, oil resistance, and the like. There is a risk that the function of highlighting (design presentation function when lit) will be impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a light-transmitting sheet capable of maintaining the function of presenting a design when lit for a long period of time.

According to the present invention, the thermoplastic elastomer composition (I) containing the cross-copolymer (A) is blended with a colorant to set the optical density (OD value) to 0.5 or more and 3.0 or less. A light transmissive sheet is provided.

Since the light-transmitting sheet of the present invention has excellent shielding properties, visibility of the design is suppressed when backlighting is not performed. In addition, the light-transmissive sheet of the present invention is excellent in transparency and long-term transparency, so it can maintain the function of presenting a design when lit for a long period of time.

Various embodiments of the present invention are illustrated below. The embodiments shown below can be combined with each other.
Preferably, the composition (I) contains 50 to 85% by mass of the cross-copolymer (A) and 15 to 50% by mass of the polyolefin resin (B).
Preferably, the above-described light-transmitting sheet, wherein the polyolefin resin (B) contains at least one of a polyethylene resin and a polypropylene resin.
Preferably, it is the light-transmitting sheet described above, wherein the gel content of the composition (I) is 1% by mass or more and 50% by mass or less.
Preferably, the permeable sheet described above, wherein the composition (I) contains 1 to 20% by mass of a styrenic thermoplastic elastomer (C) other than the cross-copolymer (A).
Preferably, the light-transmitting sheet described above contains 1 to 50 parts by mass of the plasticizer (D) per 100 parts by mass of the composition (I).
Preferably, the cross-copolymer (A) has a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via aromatic polyene monomer units. and a copolymer satisfying at least one of the following conditions (1) to (3). (1) The aromatic vinyl compound monomer unit content of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the aromatic polyene monomer unit content is 0.01 mol% or more. 0.5 mol % or less, the balance being the content of olefinic monomer units. (2) The olefin-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less and a molecular weight distribution (Mw/Mn) of 1.8 or more and 6 or less. (3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross-copolymer is in the range of 60 to 95% by mass.
Preferably, the above-described light-transmitting sheet, wherein the olefin of the cross-copolymer (A) is ethylene.
Preferably, the cross-copolymer (A) is an olefin-aromatic vinyl-aromatic polyene copolymer having an aromatic vinyl monomer unit content of 10 to 30 mol% and an aromatic 5 to 30% by mass of an aromatic vinyl polymer composed of vinyl monomer units, wherein the olefin-aromatic vinyl-aromatic polyene copolymer and the aromatic vinyl polymer are substantially separated by solvent fractionation It is the above-described light-transmitting sheet that cannot be separated by
A multilayer sheet comprising the sheet described above is preferred.
Preferably, the lighting device comprises a light-emitting member under the sheet described above.
Preferably, it is an automotive interior member using the above-described sheet or the above-described lighting device.

The present invention will be described in detail below. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope that does not impair the effects of the present invention. In addition, in the present specification and claims, the numerical range includes its lower limit and upper limit unless otherwise specified.

1. Light-Transmitting Sheet The light-transmitting sheet of the present invention is produced by blending the thermoplastic elastomer composition (I) containing the cross-copolymer (A) with a coloring agent to give an optical density (OD value) of 0.5 or more. , 3.0 or less.

The thickness of the light-transmissive sheet is preferably 0.1-1.2 mm, more preferably 0.3-0.9 mm. If the light-transmitting sheet is too thin, the shielding property tends to be lowered, and if the light-transmitting sheet is too thick, the transparency tends to be lowered.

1-1. Colorant As the colorant, any pigment or dye that can color the light-transmissive sheet can be used. The present invention is characterized in that the colorant is blended so that the optical density (OD value) of the light transmissive sheet is 0.5 or more and 3.0 or less. If the OD value is 0.5 or more, even when the light-emitting member on the back side of the seat is not lit, the lining is not transparent and looks like a general outer skin, so the appearance is excellent. When the OD value is 3.0 or less, when the light-emitting member on the back side of the sheet is turned on, the design by the light-shielding layer becomes clear, and the appearance is excellent. Therefore, by setting the OD value of the light-transmissive sheet to 0.5 or more and 3.0 or less, it is possible to realize the function of presenting the design when lit. The OD value is preferably 1.0-2.5, more preferably 1.1-2.0. This is because the appearance is further improved in this case.

1-2. Composition of Thermoplastic Elastomer Composition (I) Composition (I) contains a cross-copolymer (A). Since the cross-copolymer (A) has excellent scratch resistance, heat resistance, oil resistance, etc., the composition (I) containing the cross-copolymer (A) is used to form a light-transmitting sheet. By doing so, it becomes possible to maintain the function of presenting the design when lit for a long period of time.

Composition (I) preferably has a gel content of 1.0% by mass or more and 50% by mass or less. The gel content can be calculated from the insoluble content of composition (I) immersed in boiling xylene (140° C.) for 8 hours. When the gel content is 1.0% by mass or more, the heat resistance and oil resistance are particularly high. When the content is 50% by mass or less, good thermoplasticity and moldability are obtained. The gel content is preferably 2.0 mass % or 3.0 mass % or more.

A composition (I) with a high gel content can be obtained by a so-called dynamic cross-linking method. Dynamic cross-linking (dynamic vulcanization) is a technique in which shearing, dispersion and cross-linking are simultaneously caused by kneading various compounds in a molten state under temperature conditions at which cross-linking agents react. Such dynamic cross-linking treatment is described, for example, in Document A. Y. Coran et al., Rub. Chem. and Technol. vol. 53.141-(1980), JSR TECHNICAL REVIEW, No. 112/20050, P20-24, etc. The kneader for dynamic crosslinking is usually a Banbury mixer, a closed kneader such as a pressure kneader, a single-screw or twin-screw extruder, or the like. The kneading temperature is usually 130-300°C, preferably 150-200°C. The kneading time is usually 1 to 30 minutes.

Composition (I) preferably has an MFR (measured according to JIS K 7210-1:2014) of 0.3 g/10 min or more and 10 g/10 min or less. If the MFR (JIS K7210: 2014) of the composition (I) is less than 0.3 g/10 minutes, the molding processability may be insufficient and the economy may be lost during production. , the heat resistance and oil resistance may decrease.

The A hardness (measured based on JIS K-6253-3:2012) of composition (I) may be, for example, 100 or less, preferably 95 or less, more preferably 90 or less, and 70 or more. It can have suitable softness because A hardness is this range.

[Cross copolymer (A)]
Any cross-copolymer (A) can be used as long as the main chain of the polymer and another polymer chain are cross-bonded. In a preferred embodiment, the cross-copolymer (A) may have a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded. In a more preferred embodiment, the cross-copolymer (A) comprises an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain via an aromatic polyene monomer unit. may have a structure in which the

In a preferred embodiment, the cross-copolymer (A) may be a copolymer that satisfies one or more of the following conditions (1) to (3), more preferably two or more, and still more preferably all of them.
(1) The content of aromatic vinyl compound monomer units in the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, more preferably 12 to 28 mol%, still more preferably 15 to 25 mol%. %, and the content of the aromatic polyene monomer units is 0.01 mol% or more and 0.5 mol% or less, more preferably 0.01 mol% or more and 0.4 mol% or less, and still more preferably 0.02 mol% or more. 0.1 mol % or less, the balance being the content of olefinic monomer units.
(2) The olefin-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less, and a molecular weight distribution (Mw/Mn) of 1.8 or more and 6 or less, more preferably 1.8 or more. 5 or less, more preferably 1.8 or more and 4 or less.
(3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross-copolymer is 60 to 95% by mass, more preferably 65 to 90% by mass, and still more preferably 70 to 95% by mass. in the range of

The olefin monomer units include α-olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, vinylcyclohexane, and cyclic olefins such as cyclopentene. , norbornene, etc., can be used. Preferably, the olefin may comprise ethylene monomer, most preferably ethylene monomer.

When ethylene monomer units are used, the ethylene monomer is preferably used alone, but in addition to ethylene, a relatively small amount of an α-olefin having 3 to 20 carbon atoms within a range that does not impair the effects of the present invention, α-olefinic monomers and cyclic olefinic monomers such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, vinylcyclohexane, and cyclic olefins such as cyclopentene and norbornene You may copolymerize the monomer unit derived from.

Examples of aromatic vinyl compound monomer units include styrene and various substituted styrenes such as p-methylstyrene, m-methylstyrene, o-methylstyrene, ot-butylstyrene, mt-butylstyrene, p- Examples include units derived from styrenic monomers such as t-butylstyrene, p-chlorostyrene, o-chlorostyrene and the like. Among these, styrene units, p-methylstyrene units and p-chlorostyrene units are preferred, and styrene units are particularly preferred. These aromatic vinyl compound monomer units may be used alone or in combination of two or more.

As the aromatic polyene monomer unit, for example, an aromatic polyene having 10 or more and 30 or less carbon atoms and having a plurality of double bonds (vinyl groups) and one or more aromatic groups can be used. For example, o-divinylbenzene, p-divinylbenzene, m-divinylbenzene, 1,4-divinylnaphthalene, 3,4-divinylnaphthalene, 2,6-divinylnaphthalene, 1,2-divinyl-3,4-dimethylbenzene , 1,3-divinyl-4,5,8-tributylnaphthalene, units derived from aromatic polyene monomers, preferably orthodivinylbenzene units, paradivinylbenzene units and metadivinylbenzene units One or a mixture of two or more is preferably used.

The content in the olefin-aromatic vinyl compound-aromatic polyene copolymer is in the range of 10 to 30 mol% of the aromatic vinyl compound monomer unit from the viewpoint of improving flexibility and scratch resistance. is preferred. When the aromatic vinyl compound monomer unit is 10 mol % or more, sufficient flexibility and scratch resistance can be obtained. When the aromatic vinyl compound monomer unit content is 30 mol % or less, sufficient softness at low temperatures can be obtained, and scratch resistance can be improved.

The content of aromatic polyene monomer units may be 0.01 to 0.5 mol %, preferably 0.02 to 0.1 mol %. When the aromatic polyene monomer unit is 0.01 mol% or more, the mechanical properties are improved, and when it is 0.5 mol% or less, the moldability is improved.

The content ratio of the olefin-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain in the cross-copolymer (A) is preferably olefin- The aromatic vinyl compound-aromatic polyene copolymer chain may be 70 to 95% by mass, and the aromatic vinyl compound polymer chain may be 5 to 30% by mass. Furthermore, from the viewpoint of improving physical properties as a thermoplastic elastomer composition, 82 to 92% by mass of an olefin-aromatic vinyl compound copolymer and 8 to 18% by mass of a polymer composed of aromatic vinyl compound monomer units are used. %.

Details of the present cross-copolymer and its production method are disclosed in WO 2000/37517, WO 2007/139116, or JP 2009-120792, the entire descriptions of which are each incorporated herein by reference. described in the official gazette.

In a preferred embodiment, the olefin-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain may be linked via aromatic polyene monomer units. It is preferable that the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain cannot be substantially separated by solvent fractionation. The term "substantially" as used herein means that the present cross-copolymer may contain a relatively small amount of aromatic vinyl compound (polystyrene) homopolymer to the extent that the effect of the present invention is not impaired. do.

The weight-average molecular weight Mw of the aromatic vinyl compound polymer chain contained in the cross-copolymer (A) is arbitrary, but generally in the range of 10,000 to 80,000.

Although the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain have bonds in this cross-copolymer, it does not substantially contain gel content. and has practical moldability as a thermoplastic resin.

[Polyolefin resin (B)]
Composition (I) preferably contains polyolefin resin (B). This improves the heat resistance and oil resistance of the composition. Preferably, it contains 50 to 85% by mass of the cross-copolymer (A) and 15 to 50% by mass of the polyolefin resin (B). If the cross-copolymer (A) is less than 50% by mass, the flexibility of the obtained composition may be insufficient, and if it is more than 85% by mass, the heat resistance and oil resistance may be insufficient.

Polyolefin-based resin (B) is a polymer of one or more olefins. Alpha-olefins and cyclic olefins such as 1-pentene, 1-octene, vinylcyclohexane, and cyclic olefins, ie, cyclopentene, norbornene, can be used.

The polyolefin-based resin (B) preferably contains at least one of a polyethylene-based resin and a polypropylene-based resin, more preferably both.

A polyethylene-based resin is a resin containing 50% by mass or more of ethylene monomer units. Examples of polyethylene resins include polyethylene, ethylene/α-olefin copolymers, ethylene/vinyl acetate copolymers, ethylene/(meth)acrylic acid copolymers, and ethylene/(meth)acrylic acid ester copolymers. can be done. Examples of polyethylene include low-density polyethylene (branched ethylene polymer), medium-density polyethylene, high-density polyethylene (linear ethylene polymer) (hereinafter “HDPE”), and ultra-high molecular weight polyethylene. Examples of the ethylene/α-olefin copolymer include ethylene/butene copolymer, ethylene/hexene copolymer, ethylene/heptene copolymer, ethylene/octene copolymer, and ethylene/4-methylpentene copolymer. be done. From the viewpoint of heat resistance, the polyethylene-based resin preferably contains HDPE.

HDPE has a density of 0.940 g/cm ³ or more, preferably 0.940 to 0.970 g/cm ³ , more preferably 0.950 to 0.970 g/cm ³ . Its melting point is preferably 126 to 136 ° C. as measured by the DSC method (differential scanning calorimeter), and the melt flow rate (MFR) is specified in JIS K-6922-2: 2010 at a temperature of 190 ° C. and a load of 2.16 kg. Under measurement conditions, it is preferably 0 (substantially no flow) to 30 g/10 minutes, more preferably 0.05 to 10 g/10 minutes. When the MFR is 0.05 g/10 min or more, the thermoplastic elastomer composition has excellent processability, and when it is 10 g/10 min or less, the resulting thermoplastic elastomer composition has high mechanical properties. In addition, so-called ultra-high molecular weight polyethylene having a number average molecular weight of 1,000,000 or more can also be suitably used.

A polypropylene-based resin is a resin containing 50% by mass or more of propylene monomer units. Polypropylene resins include propylene homopolymers such as isotactic homopolypropylene, syndiotactic homopolypropylene and atactic homopolypropylene, ethylene-propylene random copolymers, ethylene-propylene block copolymers and ethylene-propylene random block copolymers. Copolymers and α-olefin-propylene copolymers typified by soft olefins (either compound type or reactor type) blended with an elastomer component can be mentioned. These polypropylene-based resins may be used alone or in combination of two or more. From the viewpoint of heat resistance, the polypropylene-based resin preferably contains block polypropylene (b-PP).

[Styrene-based thermoplastic elastomer (C) other than cross-copolymer (A)]
The composition (I) preferably contains 1 to 20% by mass of the styrenic thermoplastic elastomer (C) other than the cross-copolymer (A). This can improve the flexibility of the light transmissive sheet. As elastomer (C), for example, a thermoplastic elastomer containing a styrene portion can be used. As an example, the "Septon" series (SEP, SEPS, SEEPS, SEBS, SEEPS-OH) sold by Kuraray Co., Ltd. can be used.

[Plasticizer (D)]
Composition (I) preferably contains 1 to 50 parts by mass of plasticizer (D) per 100 parts by mass of composition (I). This can improve the flexibility of the light transmissive sheet. Further, by using the elastomer (C) and the plasticizer (D) together, it is possible to improve flexibility while preventing bleeding out.

Examples of the plasticizer (D) include paraffin-based (liquid paraffin, etc.), naphthenic, aromatic process oils, mineral oil-based softeners such as liquid paraffin, castor oil, linseed oil, olefin-based waxes, mineral-based waxes, and various Known substances such as esters can be used.

1-3. Method for Producing Thermoplastic Elastomer Composition (I) Composition (I) can be produced by blending the components constituting composition (I) and kneading them by a known method. At this time, dynamic crosslinking (dynamic vulcanization) may be performed using a crosslinking agent or a crosslinking aid, or the composition may be produced by simply kneading without using these.

2. Multilayer sheets, lighting devices, automotive interior materials.
A light-transmitting sheet using composition (I) may be a single-layer sheet or a multi-layer sheet. In the case of a multilayer sheet, it may be a multilayer sheet further comprising a layer comprising other resin component, or a multilayer sheet comprising only a layer comprising composition (I).

Further, a lighting device can be configured by arranging a light-emitting member such as an LED under the light-transmissive sheet. Such a lighting device can exhibit a design presentation function when lit. Moreover, such a lighting device can be used as an automobile interior member.

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but these are merely illustrative and do not limit the scope of the present invention. Raw materials and manufacturing methods used in Examples and Comparative Examples are as follows.

1. Preparation of Thermoplastic Elastomer Compositions of Examples and Comparative Examples The raw materials shown in Tables 1 and 2 were mixed for 1 minute in a Henschel mixer according to the formulations shown in Tables 3 and 4. The obtained mixture is kneaded using a twin-screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.) at a resin temperature of 220° C., a screw rotation speed of 170 rpm, and a residence time of 120 seconds, extruded into a strand from a die, and cut. , to obtain a thermoplastic elastomer composition (I) containing a coloring agent.

・Cross copolymer (A)
The cross-copolymers shown in Table 1 were produced by the production methods of Examples or Comparative Examples described in WO 2000/37517, WO 2007/139116, and JP-A-2009-120792. , and the following compositions were similarly determined by the methods described in these publications. In other words, the composition in the cross-copolymer and the ethylene-aromatic vinyl compound-aromatic polyene copolymer, that is, the content of ethylene, the aromatic vinyl compound, and the content of the aromatic vinyl compound polymer can be determined by ¹ H-NMR (proton NMR). The content of the aromatic polyene in the ethylene-aromatic vinyl compound-aromatic polyene copolymer was obtained from the amount of the aromatic polyene charged at the time of polymerization and the gas chromatographic analysis of the polymerization liquid sampled after completion of the coordination polymerization. The amount of aromatic polyene used in the polymerization was obtained from the difference in the amount of unreacted aromatic polyene, and was calculated by comparing with the amount of the copolymer obtained by polymerization. The molecular weight in the polymerization solution was determined by GPC measurement. The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the polystyrene chain were determined by GPC measurement of the aromatic vinyl compound polymer separated by solvent fractionation.

In these cross-copolymers, the vinyl group hydrogen (proton) peak intensity (area) of the divinylbenzene unit is the same peak of the divinylbenzene unit of the ethylene-styrene-divinylbenzene copolymer obtained in the coordination polymerization process. It was less than 20% compared to the strength (area). Actually, the hydrogen (proton) peak of the vinyl group of the divinylbenzene unit substantially disappeared in the cross-copolymer after anionic polymerization. In addition, this cross-copolymer was subjected to Soxhlet extraction using boiling acetone, but the ethylene-styrene-divinylbenzene copolymer chains (substantially ethylene-styrene copolymer chains) and polystyrene chains contained in it were extracted. could not be separated. In order to define the cross-copolymer, the styrene content, divinylbenzene content, weight average molecular weight (Mw), molecular weight distribution (Mw/Mn), and cross-copolymer of the ethylene-styrene-divinylbenzene copolymer used Content of ethylene-styrene-divinylbenzene copolymer in the polymer, weight average molecular weight (Mw) of polystyrene chain, molecular weight distribution (Mw/Mn), and MFR (JIS K7210-1, 200°C, 49N) are shown. The gel content measured by ASTM-D2765-84 was less than 0.1% by mass (below the detection limit) for any cross-copolymer.

The measurement conditions for GPC (gel permeation chromatography) were as follows.
<GPC measurement conditions>
Device name: HLC-8220 (manufactured by Tosoh Corporation)
Column: 4 Shodex GPC KF-404HQ in series Temperature: 40°C
Detection: Differential refractive index Solvent: Tetrahydrofuran Calibration curve: Prepared using standard polystyrene (PS).

・Other raw materials Other raw materials are as shown in Table 2.

2. Evaluation as a Light-Transmitting Sheet Various evaluations as a light-transmitting sheet were performed using the composition (I) having the composition shown in Tables 3 and 4 and using the physical property evaluation samples described below. The results are shown in Tables 3 and 4.

As shown in Tables 3 and 4, good results were obtained in all of the hiding properties, permeability, and long-term permeability in all the examples. On the other hand, in all of the comparative examples, the results were not good in at least one of hiding property, permeability and long-term permeability.

In Comparative Example 1, the OD value was too low, resulting in poor hiding properties. Comparative Example 2 had poor permeability and long-term permeability due to its too high OD value. Comparative Examples 3 to 5 were inferior in at least one of oil resistance, heat resistance, and scratch resistance, and thus were inferior in long-term permeability.

Example 1 containing no polyolefin resin (B) was relatively poor in heat resistance. In Example 5, in which the proportion of the cross-copolymer (A) was less than 50% by mass, the flexibility was relatively poor.

Example 3 and Examples 9 to 11 have the same blending ratio of the cross copolymer (A) and the polyolefin resin (B), but in Example 3, which does not contain an organic peroxide, dynamic No cross-linking was performed, whereas dynamic cross-linking was performed in Examples 9-11, which contained an organic peroxide. In Example 3, the gel content was less than 1% by mass, whereas in Examples 9 to 11, the gel content was 1% by mass or more as a result of dynamic cross-linking. Examples 9 to 11, in which the gel content was 1% by mass or more, were superior in permeability and long-term permeability compared to Example 2, in which the gel content was less than 1% by mass.

Example 12, in which the polyolefin-based resin (B) contains both polyethylene-based resin and polypropylene-based resin, was superior in heat resistance to Example 10, in which only one of them was included.

Compared with Example 12 containing neither elastomer (C) nor plasticizer (D), Examples 13 to 19 containing at least one of elastomer (C) and plasticizer (D) had excellent flexibility. .

In Example 17, since the OD value was less than 1, the hiding property was relatively poor. Example 18 had relatively poor permeability and long-term permeability due to an OD value greater than 2.5.

(Sample for physical property evaluation)
As a sample for evaluating physical properties, a mirror surface mold (manufactured by STAVAX) was used to heat press (200 ° C., time 5 minutes, pressure 50 kg / cm ² ) to mold the compositions of Examples and Comparative Examples. Square specular press sheets of 0.3 mm, 0.6 mm and 1 mm thickness were used. As the one-side grained mirror-finished press sheet, a one-sided grained mirror-finished press sheet having a thickness of 0.6 mm was used, which was obtained by applying a grain pattern to one side of the sheet by the same hot pressing method using a grain mold.

(Optical density (OD value))
A square mirror press sheet with a thickness of 0.3 mm or 0.6 mm and a side of 50 mm is measured according to JIS K7136 with a haze meter (NDH-1001DP type manufactured by Nippon Denshoku Industries Co., Ltd.) to measure the total light transmittance (T). It was measured. Using this total light transmittance (T), the OD value was calculated by Equation (1).

Formula (1) OD=-Log ₁₀ [T/100]

(Gel fraction)
Cut a 0.3 mm or 0.6 mm thick mirror-finished press sheet with one-sided texturing into a width of 1 mm and a length of 3 mm, immerse 0.2 g of the sheet in xylene at 140°C for 8 hours, and remove the insoluble matter through a 200-mesh metal mesh filter. and the xylene-insoluble gel content was calculated as % by mass from the dry weight.

(softness)
Instantaneous hardness was obtained using type A durometer hardness in accordance with JIS K6253-3:2012. As a test piece, six 1-mm-thick square mirror press sheets were stacked and used. A smaller value means better flexibility.

(Oil resistance)
A mirror-finished press sheet with a thickness of 0.3 mm or 0.6 mm and 20 mm on one side with a grain on one side was immersed in a 60 mL plastic bottle containing 4 g of liquid paraffin (Hicol K-350 manufactured by Kaneda Corporation) with the grain side facing up. ℃ for 7 days. After the test, the press sheet was taken out, the liquid paraffin was wiped off, and visual confirmation was performed, and the change in appearance was classified according to the following evaluation criteria.
Grade 3: Not recognized at all Grade 2: Slightly recognized but barely noticeable Grade 1: Clearly recognized

(Heat-resistant)
A 0.3 mm or 0.6 mm thick mirror-finished press sheet with one side of 50 mm was left at 110° C. for 120 hours. The gloss change value of the textured surface of the press sheet was calculated. A smaller value means better heat resistance.

(Scratch resistance)
A scratch-type hardness tester "318S" manufactured by Erichsen with a diameter of 1.0 mm ball tip (carbide) was used on the mirror side of a mirror-finished press sheet with a thickness of 0.3 mm or 0.6 mm and 50 mm on one side with grain on one side. , a scratch of 3 cm or more was drawn at a load of 3 N. The depth of the groove in the central portion of the scratch (the portion intersecting the center line of the press sheet) was measured using a surface roughness measuring instrument (Surfcoder ET4000AK manufactured by Kosaka Laboratory Ltd.). A smaller value means better scratch resistance.

(Concealability)
A 0.3 mm or 0.6 mm thick, 50 mm square mirror-finished press sheet is placed on a 50 mm side white copy paper, and the Arial font alphabet letters (A to Z) printed on the copy paper are transparent. It was visually confirmed whether it was visible, and classified according to the following evaluation criteria.
Grade 3: Can't see at all Grade 2: Can see faintly, but can't distinguish letters of the alphabet Grade 1: See clearly, can distinguish letters of the alphabet

(permeability)
A square mirror press sheet with a thickness of 0.3 mm or 0.6 mm and a side of 50 mm is placed on the display panel of a digital indicator controller (Yokogawa UT321), and the numbers (0 to 9) displayed by the red LED are It was visually confirmed whether it could be seen through and classified according to the following evaluation criteria.
Level 3: Numbers can be clearly seen and numbers can be identified Level 2: Numbers can be seen faintly and numbers can be identified Level 1: Numbers cannot be identified at all or even if visible

(long-term permeability)
A scratch resistance test, a heat resistance test, and an oil resistance test were all conducted on a mirror-finished press sheet having a thickness of 0.3 mm or 0.6 mm and a side of 50 mm with grain on one side. Using the pressed sheet after the test, the above permeability test was performed and evaluated according to the same criteria.

3. Evaluation as Automobile Interior Member The thermoplastic elastomer composition obtained in Example 13 was extruded by an extrusion sheet molding machine with a T-die set at a die temperature of 200° C. to obtain a sheet according to Example 20. The thickness of this sheet was 0.6 mm. The resulting sheet is vacuum-formed using an instrument panel mold made of polycarbonate resin under the condition that the surface temperature of the sheet is 110° C., and a light-shielding layer and a light-emitting member are placed on the back side of one part of the instrument panel mold. Thus, an automobile interior member was obtained. Table 5 shows the evaluation criteria and the results.

As shown in Table 5, good results were obtained in all evaluation items.

(Appearance of automobile interior parts)
Visual evaluation of the appearance of the automobile interior member and the emergence of the design by the light-emitting member and the light-shielding layer revealed that both were good.

(Heat cycle test)
An instrument panel type automotive interior member was subjected to a heat cycle test of 10 cycles, with 4 hours at 80° C. and 2 hours at −30° C. as one cycle. After the test, after leaving the instrument panel type automotive interior member at room temperature for 1 hour or more, 5 randomly designated parts were measured using a colorimetric color difference meter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.) L * , a*, and b* were measured, and the average value was used as the reference value. The color difference ΔE was calculated by comparing with the average values of L*, a*, and b* before the test. A color difference ΔE of 2.0 or less was defined as a passing level.

After the heat cycle test, the appearance of the instrument panel type automotive interior member was visually checked to confirm that there was no deformation, cracks, or peeling.

(chemical resistance)
A glass cleaner (genuine product number 08CBC-B010L1 manufactured by HONDA) was spread on the surface of an instrument panel type automobile interior member so that the coating amount was about 0.4 g/100 cm 2 . After being left at 80° C. for 48 hours, the appearance of the instrument panel type automotive interior member was visually checked to confirm that there was no deformation, cracks, or peeling.

(Scratch resistance)
A test piece with a diameter of about 120 mm is cut out from an instrument panel type automotive interior member, a hole with a diameter of about 6 mm is made in the center, and a Taber type scratch tester (HA-201 manufactured by Tester Sangyo Co., Ltd.) is used to test tungsten carbide. A cutter was attached, and a scratch of 3 cm or more was drawn under the conditions of a rotation speed of 0.5 rpm and a load of 3 N. After the test, the test pieces were visually checked, and changes in appearance were classified according to the following evaluation criteria. Grade 4 or higher was regarded as passing.
Grade 5: Not recognized at all Grade 4: Slightly recognized but hardly noticeable Grade 3: Slightly recognized but clearly recognized Grade 2: Somewhat significant Grade 1: Very significant

(light resistance)
For instrument panel type automotive interior materials, in accordance with JIS B7754, a xenon weather resistance tester (Atlas Ci4000 manufactured by Toyo Seiki Seisakusho Co., Ltd.) is used to test a black panel temperature of 89 ° C., humidity of 50% RH, and irradiance of 100 W / m. ² , A light resistance test was performed under the condition of a radiation exposure amount of 75 MJ/m ² . After the test, after leaving the instrument panel type automotive interior member at room temperature for 1 hour or more, 5 randomly designated parts were measured using a colorimetric color difference meter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.) L * , a*, and b* were measured, and the average value was used as the reference value. The color difference ΔE was calculated by comparing with the average values of L*, a*, and b* before the test. A color difference ΔE of 2.0 or less was defined as a passing level.

Claims (12)

A light-transmissive sheet comprising a thermoplastic elastomer composition (I) containing a cross-copolymer (A) and a coloring agent blended therein to have an optical density (OD value) of 0.5 or more and 3.0 or less. 2. The light-transmitting sheet according to claim 1, wherein the composition (I) contains 50 to 85% by mass of the cross-copolymer (A) and 15 to 50% by mass of the polyolefin resin (B). 3. The light-transmitting sheet according to claim 2, wherein the polyolefin resin (B) contains at least one of polyethylene resin and polypropylene resin. The light-transmitting sheet according to any one of claims 1 to 3, wherein the composition (I) has a gel content of 1% by mass or more and 50% by mass or less. The transmission according to any one of claims 1 to 4, wherein the composition (I) contains 1 to 20% by mass of a styrenic thermoplastic elastomer (C) other than the cross copolymer (A). sex sheet. The light-transmitting sheet according to any one of claims 1 to 5, containing 1 to 50 parts by mass of the plasticizer (D) with respect to 100 parts by mass of the composition (I). The cross-copolymer (A) has a structure in which an olefin-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via aromatic polyene monomer units. The light-transmitting sheet according to any one of claims 1 to 6, which is a copolymer that satisfies one or more of the following conditions (1) to (3).
(1) The aromatic vinyl compound monomer unit content of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 10 to 30 mol%, and the aromatic polyene monomer unit content is 0.01 mol% or more. 0.5 mol % or less, the balance being the content of olefinic monomer units.
(2) The olefin-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 or more and 300,000 or less and a molecular weight distribution (Mw/Mn) of 1.8 or more and 6 or less.
(3) The content of the olefin-aromatic vinyl compound-aromatic polyene copolymer contained in the cross-copolymer is in the range of 60 to 95% by mass. 8. The light-transmitting sheet according to claim 7, wherein the olefin of said cross-copolymer (A) is ethylene. The cross-copolymer (A) comprises 70 to 95% by mass of an olefin-aromatic vinyl-aromatic polyene copolymer having an aromatic vinyl monomer unit content of 10 to 30 mol%, and an aromatic vinyl unit It contains 5 to 30% by mass of an aromatic vinyl polymer consisting of monomer units, and the olefin-aromatic vinyl-aromatic polyene copolymer and the aromatic vinyl polymer cannot be substantially separated by solvent fractionation. The light-transmitting sheet according to any one of claims 1 to 8. A multilayer sheet comprising the sheet according to any one of claims 1-9. A lighting device comprising a light-emitting member under the sheet according to any one of claims 1 to 10. An automobile interior member using the sheet according to any one of claims 1 to 10 or the lighting device according to claim 11.