WO2018143373A1

WO2018143373A1 - Multilayer sheet for skin material

Info

Publication number: WO2018143373A1
Application number: PCT/JP2018/003490
Authority: WO
Inventors: 勝長谷川; 彰見山; 荒井　亨; 雄志熊谷
Original assignee: デンカ株式会社
Priority date: 2017-02-01
Filing date: 2018-02-01
Publication date: 2018-08-09
Also published as: JPWO2018143373A1; CN110199000A

Abstract

[Problem] To provide a multilayer sheet for skin material that exhibits an excellent adhesiveness to polypropylene (PP) layers and foam PP layers and an excellent softness, an excellent scratch abrasion resistance, and an excellent oil resistance. [Solution] Provided is a multilayer sheet for skin material having: a skin layer in which the main component is a cross copolymer; and an adhesive layer that satisfies both of the following conditions (A) and (B). (A) The adhesive layer contains at least one resin selected from thermoplastic olefin resins (TPO), thermoplastic styrene resins (TPS), and hydrogenated styrene–diene block copolymers. (B) The adhesive layer has a storage modulus at 25°C of not more than 5 × 108 Pa and a storage modulus at 125°C of at least 5 × 105 Pa.

Description

Multi-layer sheet for skin material

The present invention relates to a multilayer sheet for a skin material which is excellent in adhesiveness with a polypropylene (PP) layer and a foamed PP layer, and is excellent in softness, abrasion resistance and oil resistance.

In addition to various levels of softness, various functionalities are required for skin materials that cover the surfaces of various types of hard machines such as passenger cars, various automobiles, furniture, indoor interiors, and robots. For example, automotive interior skin materials include heat resistance, weather resistance, cold resistance, texture retention including heat history during molding, scratch resistance against human contact, and oil resistance to chemical substances accompanying humans. Chemical resistance is required.

Conventionally, skin sheets made of soft vinyl chloride (soft vinyl chloride) with a plasticizer added have been used in such fields. Soft PVC is a material that is excellent in softness, oil resistance, and scratch resistance, and is advantageous in price. However, soft vinyl chloride is a problem of management during incineration, that is, volatile organic compounds (VOC) due to plasticizers contained in large quantities in recent years, concerns as environmental hormones although some plasticizers, and heavy metal stabilizers Therefore, there is a demand for materials that are more environmentally friendly. Therefore, a skin material sheet made of TPO (thermoplastic olefin resin) or TPS (thermoplastic styrene resin) has attracted attention. TPO and TPS are characterized by heat resistance, softness, recyclability, and environmental characteristics, and have been widely used. These materials are compounds composed of a soft component and a heat-resistant component. However, the PP (isotactic polypropylene) component used as the heat-resistant component has a problem that the wear resistance with scratches is lowered to an insufficient level. ing. Also, the cross-linked ethylene-propylene rubber used as a soft component and the cross-linked or non-cross-linked styrene-based hydrogenated block copolymer have insufficient oil resistance, which may cause swelling and deformation in the harsh environment described above. is there. When the abrasion resistance is improved by reducing the amount of PP added or the like, there is a problem that the heat resistance, particularly the surface wrinkle retention at the time of sheet molding is lowered and wrinkles disappear. Further, when crosslinking is performed on a soft component and / or a hard component, the cost is increased, and there are also problems such as odors derived from various crosslinking materials and auxiliary agents.

In order to cope with such a problem, the present inventors have proposed a cross copolymer which is a new soft resin (Patent Document 1). This resin is characterized in that it can be adjusted in a wide range of hardness from soft to semi-rigid without a plasticizer, and has excellent scratch resistance and oil resistance (Patent Document 2). In order to use the resin itself for the above-mentioned purposes, it is preferable to improve the heat resistance and the texture retention during use as a skin material sheet or during molding. From such a background, the heat resistance has been improved by blending a heat-resistant resin into the cross copolymer. When PP is added to enhance heat resistance, the scratch resistance and wear resistance is reduced as in TPO and TPS. Therefore, the addition of PPE (polyphenylene ether) resin (Patent Document 3) and the addition of TPEE (Polyester-based soft resin) (Patent Document 4) have been attempted to improve heat resistance. Particularly when PPE is added, the abrasion resistance and oil resistance are further improved. In the case of TPEE addition, higher levels of heat resistance and softness can be maintained. Further, the heat resistance of the styrene-ethylene cross copolymer sheet can be improved by electron beam crosslinking. Patent Document 1 describes particularly a tape base material, an electric wire coating material, and a foam material using an electron beam cross-linked body of a cross copolymer.
International Publication No. 2007/139116 JP 2009-102515 A International Publication No. 2009/128444 JP 2010-242151 A

By the way, in order to obtain a soft feel, a skin material sheet for an automobile interior often has a foamed polypropylene sheet as a base (base material) layer. The skin material sheet made of TPO or TPS can be easily adhered to the foamed polypropylene sheet. For example, the skin material sheet and the foamed layer can be adhered by a simple thermal lamination method. However, a skin material sheet made of a conventional styrene-ethylene cross copolymer has a problem that it is difficult to thermally laminate with a foamed polypropylene sheet.
Styrene-ethylene cross-copolymer is a multilayer film for skin materials and a base material layer (mainly polypropylene) in a molding method involving injection molding of a base material layer (mainly polypropylene) such as film insert molding and in-mold molding. It is also useful as a multilayer film for TOM molding upward. Also in this case, good adhesion between the base material layer and the skin layer is important.

The present invention relates to a multilayer sheet for a skin material which is excellent in adhesiveness with a polypropylene base layer and is excellent in softness, scratch-resistant wear and oil resistance.

The present invention employs the following means in order to solve the above problems.
[1] A multilayer sheet for a skin material comprising a skin layer mainly composed of a cross-copolymer and an adhesive layer satisfying the following conditions (A) and (B) on one surface of the skin layer.
(A) The adhesive layer contains at least one resin selected from a thermoplastic olefin resin (TPO), a thermoplastic styrene resin (TPS), and a hydrogenated styrene-diene block copolymer.
(B) The storage elastic modulus at 25 ° C. of the adhesive layer is 5 × 10 ⁸ Pa or less, and the storage elastic modulus at 125 ° C. is 5 × 10 ⁵ Pa or more.
[2] The cross copolymer has a structure in which an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. Furthermore, the multilayer sheet for skin material according to [1], which further satisfies the following conditions (1) to (3):
(1) The content of the aromatic vinyl compound monomer unit of the ethylene-aromatic vinyl compound-aromatic polyene copolymer is 5 mol% or more and 40 mol% or less, and the content of the aromatic polyene monomer unit is 0.01 More than mol% and less than 0.2 mol%, the remainder is ethylene monomer units.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 to 300,000 and a molecular weight distribution (Mw / Mn) of 1.8 to 6.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is 40% by mass or more and 90% by mass or less.
[3] The skin according to [1] or [2], wherein the cross copolymer is a graft-through copolymer of an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain. Multi-layer sheet for materials.
[4] Any one of [1] to [3], wherein one or more base material layers selected from foamed polypropylene and polypropylene are further laminated on the surface of the adhesive layer opposite to the surface in contact with the skin layer. A multilayer sheet for a skin material as described in Crab.
[5] The multilayer sheet for skin material according to any one of [1] to [4], which is for film insert molding, in-mold molding, or TOM molding.
[6] The multilayer sheet for skin material according to any one of [1] to [5], wherein the cross copolymer satisfies all the following conditions (4) to (7):
(4) By ¹ H-NMR measurement, peaks attributed to the ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer were observed, and the aromatic vinyl compound in the ethylene-aromatic vinyl compound copolymer was observed. The content is 5 to 40 mol%, the content of the ethylene-aromatic vinyl copolymer component contained is in the range of 40 to 90% by mass,
(5) The ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer contained have a bond,
(6) MFR (200 ° C., weight 49 N) is in the range of 0.05 to 50 g / 10 minutes,
(7) The gel content is 0.2% by mass or less.
[7] A skin material formed using the multilayer sheet for skin material according to any one of [1] to [6].

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in adhesiveness with the polypropylene (PP) layer and foamed PP layer which are base material layers, and provides the multilayer sheet for skin materials which is excellent in softness | flexibility, abrasion-resistant abrasion, and oil resistance. it can.

It is a figure which shows the multilayer sheet for skin materials of this invention. It is a figure which shows the multilayer sheet for skin materials which laminated | stacked the base material layer.

Hereinafter, an embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within a range that does not impair the effects of the present invention.

[Multilayer sheet for skin material]
An example of a multilayer sheet for skin material according to the present embodiment (hereinafter also simply referred to as “multilayer sheet”) is shown in FIG. As shown in FIG. 1, the multilayer sheet 3 for skin material has a skin layer 1 and an adhesive layer 2. Specifically, the multilayer sheet for skin material is a multilayer sheet for skin material having a skin layer mainly composed of a cross-copolymer and an adhesive layer satisfying all the following conditions (A) and (B).
(A) The adhesive layer is a resin selected from a thermoplastic olefin resin (TPO), a thermoplastic styrene resin (TPS), and a hydrogenated styrene-diene block copolymer.
(B) The storage elastic modulus at 25 ° C. of the adhesive layer is 5 × 10 ⁸ Pa or less, and the storage elastic modulus at 125 ° C. is 5 × 10 ⁵ Pa or more.

(Skin layer)
The skin layer is mainly composed of a cross copolymer. “Main component” means 50% by mass or more, 80% by mass or more, 90% by mass or more, and preferably 95% by mass or more of the resin constituting the skin layer.
Here, the cross-copolymer is obtained by a production method comprising a coordination polymerization step followed by an anionic polymerization step. As the coordination polymerization step, a single site coordination polymerization catalyst is used to form an ethylene monomer unit, an aromatic An ethylene-aromatic vinyl compound-aromatic polyene copolymer by copolymerizing an aromatic vinyl monomer unit and an aromatic polyene monomer unit, and then, as an anionic polymerization step, this ethylene-aromatic vinyl compound -A copolymer obtained by polymerization using an anionic polymerization initiator in the presence of an aromatic polyene copolymer and an aromatic vinyl monomer unit, and the following conditions (1) to (3): It is a copolymer satisfying all of the above.
(1) The content of aromatic vinyl monomer units in the ethylene-aromatic vinyl compound-aromatic polyene copolymer obtained in the coordination polymerization step is 5 mol% to 40 mol%, preferably 10 mol% to 30 mol. The mol% or less, the content of aromatic polyene monomer units is 0.01 mol% or more and 0.2 mol% or less, and the balance is the content of ethylene units.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer obtained in the coordination polymerization step has a weight average molecular weight of 50,000 to 300,000 and a molecular weight distribution (Mw / Mn) of 1.8 to 6 is there.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is in the range of 40% by mass to 90% by mass. Furthermore, the skin layer mainly composed of the cross copolymer is a skin layer in which the total amount of other resins, fillers, additives, etc. added is 110 parts by mass or less with respect to 100 parts by mass of the present cross copolymer. Means.

Hereinafter, the cross copolymer will be described. This cross-copolymer is a copolymer having an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain derived from a macromonomer, ethylene-aromatic vinyl compound-aromatic It has a structure in which an aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit.

The fact that the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain are bonded via the aromatic polyene monomer unit can be proved by the following observable phenomenon. Here, an example in which a typical ethylene-styrene-divinylbenzene copolymer chain and a polystyrene chain are bonded via a divinylbenzene unit is shown. That is, the ethylene-styrene-divinylbenzene copolymer (macromonomer) obtained in the coordination polymerization step, and ¹ H- of the cross-copolymer obtained through anionic polymerization in the presence of this copolymer and a styrene unit. NMR (proton NMR) was measured, and the peak intensity of vinyl group hydrogen (proton) of both divinylbenzene units was determined using an appropriate internal standard peak (appropriate peak derived from an ethylene-styrene-divinylbenzene copolymer). Compare. Here, the peak intensity (area) of the vinyl group hydrogen (proton) of the divinylbenzene unit of the cross copolymer is the same peak intensity (area) of the divinylbenzene unit of the ethylene-styrene-divinylbenzene copolymer (macromonomer). And 50% or less, preferably 20% or less. In the anionic polymerization (cross-linking step), the divinylbenzene unit is copolymerized simultaneously with the polymerization of the styrene unit, and the ethylene-styrene-divinylbenzene copolymer chain and the polystyrene chain are bonded via the divinylbenzene unit. In the cross-copolymer after anionic polymerization, the peak intensity of hydrogen (proton) of vinyl group of divinylbenzene unit is greatly reduced. Actually, the hydrogen (proton) peak of the vinyl group of the divinylbenzene unit substantially disappears in the cross-copolymer after the anionic polymerization. For details, see the publicly known document “Synthesis of a branched copolymer using an olefin copolymer containing a divinylbenzene unit”, Jun Arai, Masaru Hasegawa, Journal of the Japan Rubber Association, p382, vol. 82 (2009).

From another viewpoint, in the present cross copolymer, the ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and the aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit ( As an example, the fact that an ethylene-styrene-divinylbenzene copolymer chain and a polystyrene chain are bonded via a divinylbenzene unit can be proved by the following observable phenomenon. That is, even after the Soxhlet extraction is carried out a sufficient number of times using an appropriate solvent, the contained ethylene-styrene-divinylbenzene copolymer chain cannot be separated from the polystyrene chain. Usually, ethylene-styrene-divinylbenzene copolymer (or ethylene-styrene copolymer) and polystyrene having the same composition as the ethylene-styrene-divinylbenzene copolymer chain contained in this cross-copolymer are made of Soxhlet with boiling acetone. By performing extraction, it is possible to fractionate into an ethylene-styrene-divinylbenzene copolymer (or ethylene-styrene copolymer) as an acetone-insoluble part and to polystyrene as an acetone-soluble part. However, when the same Soxhlet extraction is performed on the cross copolymer, a relatively small amount of polystyrene homopolymer contained in the cross copolymer is obtained as the acetone soluble part, but the acetone insoluble, which accounts for the majority, is obtained. The NMR measurement shows that the ethylene-styrene-divinylbenzene copolymer chain and the polystyrene chain are both contained in the part, and it can be seen that these cannot be separated by Soxhlet extraction. Details of this are also described in the publicly known document “Synthesis of a branched copolymer using an olefin copolymer containing a divinylbenzene unit”, Jun Arai, Masaru Hasegawa, Journal of Japan Rubber Association, p382, vol. 82 (2009).

From the above, the expression defining the cross-copolymer constituting this embodiment is that the cross-copolymer has an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain. A copolymer having a structure in which an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit. The cross-copolymer may contain a relatively small amount of an aromatic vinyl compound (polystyrene) homopolymer.
The cross copolymer is more preferably a copolymer that satisfies all the following conditions (1) to (3).
(1) The content of aromatic vinyl monomer units in the ethylene-aromatic vinyl compound-aromatic polyene copolymer obtained in the coordination polymerization step is 5 mol% to 40 mol%, preferably 10 mol% to 30 mol. Mol% or less, the content of aromatic polyene monomer units is 0.01 mol% or more and 0.2 mol% or less, preferably 0.02 mol% or more and 0.1 mol% or less, and the balance is the content of ethylene units. .
(2) The weight average molecular weight of the ethylene-aromatic vinyl compound-aromatic polyene copolymer obtained in the coordination polymerization step is 50,000 to 300,000, preferably 60,000 to 250,000, and the molecular weight distribution (Mw / Mn) is 1.8 or more and 6 or less. In addition, a weight average molecular weight and molecular weight distribution (Mw / Mn) can be measured by normal GPC (gel permeation chromatography).
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross-copolymer is in the range of 40 mass% to 90 mass%, preferably 60 mass% to 90 mass%. .

The weight average molecular weight Mw of the aromatic vinyl compound polymer chain is arbitrary, but is generally in the range of 10,000 to 80,000. In the cross copolymer, the molecular weight of the aromatic vinyl compound polymer chain bonded to the main chain ethylene-aromatic vinyl compound-aromatic polyene copolymer cannot be determined. The weight average molecular weight Mw of the aromatic vinyl compound polymer homopolymer contained in a relatively small amount in the copolymer is defined as the weight average molecular weight Mw of the aromatic vinyl compound polymer chain contained in the cross copolymer. Yes.

As a result of ¹ H-NMR measurement of the cross-copolymer, the amount of aromatic polyene (divinylbenzene) unit contained is significantly less than that of the aromatic vinyl compound (styrene) unit, and the peak position is the aromatic vinyl compound. Since it overlaps with the (styrene) unit, the peak cannot be confirmed directly. Therefore, in the ¹ H-NMR measurement of the present cross-copolymer, the peak derived from the ethylene-aromatic vinyl compound copolymer (ethylene-styrene copolymer) and the peak derived from the aromatic vinyl compound polymer (polystyrene) The ethylene unit content, the aromatic vinyl compound (styrene) unit content derived from the ethylene-aromatic vinyl compound copolymer (ethylene-styrene copolymer) of the cross copolymer, and the weight of the aromatic vinyl compound The content of coalesced (polystyrene) can be determined. Here, in this case, the aromatics actually contained in the ethylene-aromatic vinyl compound-aromatic polyene copolymer (ethylene-styrene-divinylbenzene copolymer) in an amount of 0.01 mol% to 0.2 mol%. The content of polyene (divinylbenzene) is excluded from the fact that it is not detected by ¹ H-NMR measurement, and the respective contents are obtained. The acetone-insoluble part occupying most of the cross-copolymer contains both an ethylene-aromatic vinyl compound copolymer (ethylene-styrene copolymer) and an aromatic vinyl compound polymer (polystyrene). This cannot be separated by further fractionation operations. Therefore, in the present cross copolymer, the ethylene-aromatic vinyl compound copolymer chain and the aromatic vinyl compound polymer chain have a bond (for example, the ethylene-styrene copolymer chain and the polystyrene chain). Can be proved). This cross-copolymer is substantially free of gels and has thermoplasticity despite the fact that the ethylene-aromatic vinyl compound copolymer chain and the aromatic vinyl compound polymer chain have a bond. Practical moldability as a resin, that is, a specific MFR value can be shown.

As described above, the cross copolymer can be defined as a copolymer satisfying all the following conditions (4) to (7) from the viewpoint of detectability.
(4) From ¹ H-NMR measurement, peaks attributed to the ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer were observed, and the content of aromatic vinyl compound in the ethylene-aromatic vinyl compound was 5 -40 mol%, more preferably 10-30 mol%, and the content of the ethylene-aromatic vinyl compound copolymer component contained is in the range of 40-90 mass%, more preferably 60-90 mass%,
(5) The ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer contained have a bond,
(6) MFR (200 ° C., weight 49 N) is in the range of 0.05 to 50 g / 10 min, more preferably in the range of 0.1 to 20 g / 10 min.
(7) The gel content is 0.2% by mass or less, more preferably 0.1% by mass or less.
The melt flow rate (MFR) can be measured according to JIS K 7210. The gel content can be determined according to ASTM-D2765-84.

The cross-copolymer will be described from another viewpoint. This cross-copolymer is obtained by a production method including a polymerization step comprising a coordination polymerization step and an anionic polymerization step. As the coordination polymerization step, a single site coordination polymerization catalyst is used to produce ethylene units and aromatic vinyl monomers. The ethylene-aromatic vinyl compound-aromatic polyene copolymer is synthesized by copolymerization of the body unit and the aromatic polyene monomer unit, and then, as an anionic polymerization step, the ethylene-aromatic vinyl compound-aromatic It is a copolymer produced by anionic polymerization with an anionic polymerization initiator in the presence of a polyene copolymer (macromonomer) and an aromatic vinyl monomer unit. The aromatic vinyl monomer unit used in the anionic polymerization step may be an unreacted monomer remaining in the polymerization solution in the coordination polymerization step, or a new aromatic vinyl compound monomer may be added thereto. good. Anionic polymerization is initiated by adding an anionic polymerization initiator to the polymerization liquid. In this case, the polymerization liquid is compared with an aromatic polyene monomer unit of an ethylene-aromatic vinyl compound-aromatic polyene copolymer. However, the anionic polymerization starts substantially from the overwhelmingly large aromatic vinyl monomer units, and the ethylene-aromatic vinyl compound-aromatic polyene copolymer is polymerized while polymerizing the aromatic vinyl monomer units. While the vinyl group of the aromatic polyene monomer unit is copolymerized, the polymerization proceeds. Therefore, according to known literature and knowledge of those skilled in the art, the obtained cross-copolymer has an ethylene-aromatic vinyl compound-aromatic polyene copolymer as a main chain and an aromatic vinyl compound polymer chain as a cross-chain. Many structures (cross bonds) bonded in a graft-through manner are included, that is, an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain via an aromatic polyene monomer unit. It is thought that there are many structures linked together.

From the above, the expression defining the cross-copolymer of the present embodiment is preferably a grafting copolymer of an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain. It is a polymer.

The cross copolymer preferably has an A hardness in the range of 55 to 85 in general. The A hardness can be determined as a type A durometer hardness under the condition of 23 ± 1 ° C. according to the JIS K-7215 plastic durometer hardness test method.

Examples of aromatic vinyl monomer units include styrene and various substituted styrenes such as p-methylstyrene, m-methylstyrene, o-methylstyrene, ot-butylstyrene, mt-butylstyrene, pt Examples thereof include units derived from styrene monomers such as -butylstyrene, p-chlorostyrene, and o-chlorostyrene. Industrially, styrene units, p-methylstyrene units, p-chlorostyrene units, particularly preferably styrene units are used. These aromatic vinyl monomer units may be used alone or in combination of two or more.

The aromatic polyene monomer unit has 10 to 30 carbon atoms, has a plurality of double bonds (vinyl group) and one or more aromatic groups, and is a double bond (vinyl group). Even if one is used in coordination polymerization and polymerized, the remaining double bond is an aromatic polyene capable of anion polymerization. Preferably, any one or a mixture of two or more of an orthodivinylbenzene unit, a paradivinylbenzene unit and a metadivinylbenzene unit is preferably used.

In the production of the olefin-aromatic vinyl compound copolymer or olefin-aromatic vinyl compound-aromatic polyene copolymer in the coordination polymerization step, the monomers, transition metal compounds and promoters exemplified above are used. Although it makes contact, arbitrary well-known methods can be used for the order of contact and the contact method.
As the above copolymerization method, polymerization is performed in a liquid monomer without using a solvent, or pentane, hexane, heptane, cyclohexane, benzene, toluene, ethylbenzene, xylene, chloro-substituted benzene, chloro-substituted toluene, chloride There is a method using a saturated aliphatic or aromatic hydrocarbon such as methylene or chloroform or a halogenated hydrocarbon alone or in a mixed solvent. Preferably, a mixed alkane solvent, cyclohexane, toluene, ethylbenzene or the like is used.

Polymerization form may be either solution polymerization or slurry polymerization. Moreover, well-known methods, such as batch polymerization, continuous polymerization, prepolymerization, and multistage polymerization, can be used as needed. It is also possible to use a single tank or a plurality of connected tank polymerization cans, or a single linear or loop, or a plurality of connected pipe polymerization equipment. Pipe-shaped polymerization cans include various known mixers such as dynamic or static mixers and static mixers that also remove heat, and various known mixers such as coolers equipped with heat removal thin tubes. You may have a cooler. Moreover, you may have a batch type prepolymerization can. Furthermore, methods such as gas phase polymerization can be used.

The polymerization temperature is suitably from 0 to 200 ° C. A polymerization temperature lower than 0 ° C is industrially disadvantageous, and if it exceeds 200 ° C, the transition metal compound is decomposed, which is not suitable. Further, industrially preferred is 0 to 160 ° C, particularly preferred is 30 to 160 ° C. The pressure during the polymerization is suitably 0.09 to 10 MPa, preferably 0.09 to 3 MPa, and industrially particularly preferably 0.09 to 0.98 MPa.

In the anionic polymerization step, polymerization is performed using an anionic polymerization initiator in the presence of an ethylene-aromatic vinyl compound-aromatic polyene copolymer and an aromatic vinyl monomer unit.
As the solvent for anionic polymerization, a mixed alkane solvent that does not cause inconvenience such as chain transfer during anionic polymerization, a solvent such as cyclohexane, benzene, etc. is particularly preferable, but other solvents such as toluene, ethylbenzene, etc. may also be used. Is possible. As the polymerization form, any known method used for anionic polymerization can be used.

In the present embodiment, the order of adding the aromatic vinyl monomer unit and the anionic polymerization initiator is arbitrary. That is, an anionic polymerization initiator may be added after adding an aromatic vinyl monomer unit to the polymerization solution and stirring, or an aromatic vinyl monomer unit may be added after adding an anionic polymerization initiator. In the former, there are many structures (cross bonds) in which the ethylene-olefin-aromatic polyene copolymer obtained in the coordination polymerization process as the main chain and the aromatic vinyl compound polymer chain as the cross chain are bonded in a graft-through manner. In the latter case, it is considered that many graft from (branched bonds) structures are included. Polymerization with better reproducibility and industrial preference is the former. The cross copolymer of the present embodiment is a copolymer obtained by a specific production method, and its structure is arbitrary. The polymerization temperature is suitably −78 to 200 ° C. A polymerization temperature lower than −78 ° C. is industrially disadvantageous, and if it exceeds 200 ° C., chain transfer or the like occurs, which is not suitable. Furthermore, industrially preferred is 30 to 150 ° C.
The pressure during the polymerization is generally suitably from 0.09 to 10 MPa, preferably from 0.09 to 3 MPa, particularly industrially particularly preferably from 0.09 to 0.98 MPa.

In the anionic polymerization step, a known anionic polymerization initiator can be used. Preferably, alkyl lithium compounds, lithium salts such as biphenyl, naphthalene, and pyrene or sodium salts, particularly preferably sec-butyl lithium and n (normal) -butyl lithium are used. Moreover, you may use a polyfunctional initiator, a dilithium compound, and a trilithium compound. Furthermore, you may use a well-known anionic polymerization terminal coupling agent as needed. In the case of using methylalumoxane as a co-catalyst for the polymerization catalyst in the coordination polymerization step, the initiator is used in an amount of at least the equivalent of oxygen atoms contained therein, particularly preferably at least 2 equivalents. Is preferred. When a boron compound is used as a co-catalyst for the polymerization catalyst in the coordination polymerization step, the amount is sufficiently smaller than the oxygen atom equivalent in methylalumoxane, so the amount of initiator can be reduced. is there.

For details of the present cross-copolymer and its production method, the entire description thereof is incorporated herein by reference, International Publication No. 2000/37517, International Publication No. 2007/139116, or Japanese Patent Application Laid-Open No. 2009-12092. It is described in the publication.

For the skin layer mainly composed of the cross-copolymer, a resin composed mainly of the cross-copolymer, that is, a resin composition is used. For example, for the purpose of imparting scratched abrasion resistance, oil resistance, and heat resistance. As various resin compositions described in International Publication No. 2000/37517, International Publication No. 2007/139116, or Japanese Patent Application Laid-Open No. 2009-12092, PPE (polyphenylene ether) resin described in International Publication No. 2009-128444 Or TPEE (polyester-based soft resin) described in JP-A-2010-242015 may be added mainly for the purpose of imparting heat resistance. The addition amount depends on the purpose of the present multilayer sheet, but it is appropriate to add up to 110 parts by mass of these resins with respect to 100 parts by mass of the cross-copolymer. Addition beyond this may result in loss of the softness of the skin material sheet. Furthermore, the resin composition described in International Publication No. 2015/072466 can also be suitably used for the purpose of imparting scratched abrasion resistance, oil resistance, and heat resistance.

Moreover, it can bridge | crosslink for the purpose of preventing heat resistance improvement and decoration, such as a wrinkle, disappearing | disappearing and deform | transforming during a secondary shaping | molding process. For such crosslinking, dynamic crosslinking is used. A method for dynamically curing a cross-copolymer is described in WO2000 / 37517.
Preferably, cross-linking with an electron beam is performed on the skin layer, and in particular, cross-linking in the vicinity of the surface can be performed. Such electron beam crosslinking is described in, for example, Japanese Patent Application Laid-Open No. 2011-207936.

The thickness of the skin layer of the multilayer sheet for skin material is arbitrary, but is generally 100 μm to 2 mm. The multi-layer sheet for the skin material may be decorated with a texture, etc., and a protective layer may be further provided on the skin layer, and it can improve scratch resistance, wear resistance, and slipperiness. For the purpose, coating with urethane, silicone or the like may be performed.

(Adhesive layer)
The adhesive layer is an adhesive layer that satisfies all the following conditions (A) and (B).
(A) The adhesive layer contains a resin selected from a thermoplastic olefin resin (TPO), a thermoplastic styrene resin (TPS), and a hydrogenated styrene-diene block copolymer. The content of the resin is preferably 50% by mass or more, more preferably 70% by mass or more, 80% by mass or more, or 95% by mass or more in the components constituting the adhesive layer.
(B) The storage elastic modulus at 25 ° C. of the adhesive layer is 5 × 10 ⁸ Pa or less, and the storage elastic modulus at 125 ° C. is 5 × 10 ⁵ Pa or more.

The thickness of the adhesive layer is not particularly limited, but is generally 1 μm to 1 mm. When foamed PP is used for the base material layer, the thinner one can take advantage of the soft and elastic features of the foamed PP layer. The thickness is preferably 1 μm to 300 μm, and particularly preferably 1 μm to 100 μm.

The thermoplastic olefin resin (TPO) used in the adhesive layer is made of polyolefin such as polypropylene and polyethylene as a hard segment, and rubber / elastomer components such as ethylene-propylene rubber (EPM, EPDM) and ethylene-α olefin copolymer. These are thermoplastic elastomers having a soft segment, and these may be any of a blend type, a dynamic crosslinking type (TPV), and a polymerization type (Reactor-TPO). Preferred commercially available thermoplastic olefin resins (TPO) include Thermoran (Mitsubishi Chemical Co., Ltd.), Excelin (JSR Co., Ltd.), Miralastomer (Mitsui Chemicals Co., Ltd.), Santoprene (ExxonMobil Corp.), Prime TPO ( Examples include Prime Polymer Co., Ltd., Catalloy (manufactured by Lyon Del Basel), and Newcon (Nihon Polypro Co., Ltd.).

The concept of a thermoplastic olefin resin (TPO) includes a resin composition containing an ethylene-α olefin copolymer and polypropylene. Instead of purchasing and using the above commercially available TPO, a resin composition containing an ethylene-α-olefin copolymer and polypropylene can be produced and used. The α-olefin in the ethylene-α-olefin copolymer is an α-olefin having 3 to 12 carbon atoms, and one or more α-olefins may be used. Examples of the ethylene-α olefin copolymer include an ethylene-propylene copolymer, an ethylene-butene copolymer, an ethylene-hexene copolymer, or an ethylene-octene copolymer. The α-olefin content in the ethylene-α-olefin copolymer is preferably 10 to 40% by mass from the viewpoint of adhesiveness. The ethylene-α-olefin copolymer may contain a polyvalent ene component such as ethylidene norbornene or 1,4-hexadiene. The ethylene-α olefin copolymer has an MFR measured in accordance with JIS K7210 of 0.5 to 20 g / min. It is preferable that Further, the ethylene-α-olefin copolymer preferably has a density of 0.850 to 0.900 g / cm ³ in terms of mechanical properties. A polypropylene-free, for example, ethylene-α-olefin copolymer alone is not preferred because it exhibits adhesiveness but lacks heat resistance necessary for the skin adhesive layer. The adhesive layer made of thermoplastic olefin resin (TPO) may be kneaded and blended with a cross copolymer used for the skin layer. In this case, the cross-copolymer is blended in an amount of 1 to 200 parts by weight, preferably 20 to 150 parts by weight, based on 100 parts by weight of the thermoplastic olefin resin (TPO).

The thermoplastic styrenic resin (TPS) used for the adhesive layer of the multilayer sheet for skin material is a blend mainly composed of a hydrogenated styrene-diene block copolymer or a dynamic vulcanizate thereof. The styrene-diene block copolymer thus obtained is distinguished from that used alone as the adhesive layer resin. The thermoplastic styrene resin (TPS) is, for example, a hydrogenated styrene-diene block copolymer (for example, 20 to 90% by mass in the resin composition), a polyolefin such as polypropylene (for example, 5 to 50 in the resin composition). Mass%, or 5 to 40 mass%). In addition, oil may be blended and kneaded and blended if necessary, or further dynamic vulcanization is performed.
The hydrogenated styrene-diene block copolymers used are generally polystyrene-poly (ethylene / propylene) block (SEP), polystyrene-poly (ethylene / propylene) block-polystyrene (SEPS), polystyrene-poly (ethylene). / Butylene) block-polystyrene (SEBS), polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene (SEEPS), which may be diblock, triblock or multiblock, preferably a hard chain polystyrene chain Is a block copolymer having a plurality of Preferably, commercially available Septon (manufactured by Kuraray Co., Ltd.), Kraton G polymer (manufactured by Kraton Polymer Japan Co., Ltd.), Tuftec (manufactured by Asahi Kasei Co., Ltd.) (named above) is used. Moreover, as a commercially available thermoplastic styrene resin (TPS), lavalon (made by Mitsubishi Chemical Corporation), a septon compound, and Arneston (made by Kuraray Plastics Co., Ltd.) can be illustrated. From the viewpoint of heat resistance of the adhesive layer, a thermoplastic styrene resin (TPS) is preferably used.
Further, the hydrogenated styrene-diene block copolymer alone can be used as the adhesive layer resin. When the hydrogenated styrene-diene block copolymer is used alone, it may contain additives such as a stabilizer and oil, but its content is 10 parts by mass with respect to 100 parts by mass of the resin. It is preferable to make it less than.
Further, the above-mentioned thermoplastic styrene resin (TPS) or hydrogenated styrene-diene block copolymer may be kneaded and blended with the above-mentioned cross-copolymer used for the skin layer. In this case, the cross-copolymer is blended in an amount of 1 to 200 parts by mass, preferably 20 to 150 parts by mass with respect to 100 parts by mass of the thermoplastic styrene resin (TPS).

The storage elastic modulus at 25 ° C. of the adhesive layer of the multilayer sheet for skin material is 5 × 10 ⁸ Pa or less. Moreover, it is preferable that a lower limit is 1 * 10 < ⁶ > Pa or more. Since the storage elastic modulus at 25 ° C. is 5 × 10 ⁸ Pa or less, the softness of the multi-layer sheet for skin material is maintained, and the softness and elasticity of the foamed PP layer used for the substrate can be reflected. By setting the storage elastic modulus to 1 × 10 ⁶ Pa or more, the peel strength can be sufficiently maintained.

The storage elastic modulus of the adhesive layer at 125 ° C. is 5 × 10 ⁵ Pa or more, preferably 1 × 10 ⁶ Pa or more and 1 × 10 ⁸ Pa or less. Since the storage elastic modulus at 125 ° C. is 5 × 10 ⁵ Pa or more, the peel strength between the adhesive layer and the skin layer or the base material layer (foamed PP layer or PP layer) at a high temperature can be maintained. By setting the storage elastic modulus to 1 × 10 ⁸ Pa or less at 125 ° C., the softness from room temperature to near high temperature can be maintained. The separation strength (180 ° peel test) between the multilayer sheet for the skin material and the base material layer is preferably 10 N / 25 mm or more at 25 ° C., more preferably 20 N / 25 mm or more.
Since the adhesive layer is also excellent in heat sealability (thermal weldability), it can be easily adhered to the base material layer even when the base material layer described later is laminated, and the adhesive strength with the base material layer can be increased. Can be increased.

(Production method)
Arbitrary well-known methods are employable as a manufacturing method of a multilayer sheet. Examples of such methods include dry lamination, thermal lamination, extrusion lamination, and coextrusion. Examples of the adhesive used in the dry laminating method and the extrusion laminating method include polyvinyl acetate adhesives, polyacrylate adhesives, reactive (meth) acrylic adhesives, cyanoacrylate adhesives, ethylene and acetic acid. Ethylene copolymer adhesives made of copolymers with monomers such as vinyl, ethyl acrylate, acrylic acid, methacrylic acid, etc., polyester adhesives, polyamide adhesives, polyimide adhesives, urea resins or melamine resins Adhesives such as amino resin adhesives, phenol resin adhesives, epoxy adhesives, polyurethane adhesives, rubber adhesives made of chloroprene rubber, styrene-butadiene rubber, etc. can be used. . The composition system of the above-mentioned adhesive may be any composition form such as an aqueous type, a solution type, an emulsion type, and a dispersion type, and the property is any of film / sheet form, powder form, solid form, etc. Further, the bonding mechanism may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, and a hot pressure type. The adhesive can be applied by, for example, a roll coating method, a gravure roll coating method, a kiss coating method, a coating method such as others, or a printing method, and the coating amount is 0.1 to 10 g / m. ² (dry state) is desirable.

Further, in the production of a multilayer sheet, a heat laminating method, that is, a method in which a pre-formed skin layer sheet or adhesive layer sheet is pressure-bonded using a roll or a press method in a temperature range of 130 to 280 ° C. can be employed.

Industrially, the multilayer sheet is preferably formed into a film by coextrusion in which a resin or a resin composition that is a raw material for the skin layer and the adhesive layer is fused and integrated by separate extruders. Further, it is preferable to perform melt coextrusion molding in a temperature range of 130 to 280 ° C. As the coextrusion method, a T-die coextrusion method or an inflation coextrusion method can be used. As each extruder, a single screw extruder, a twin screw (multi-screw) extruder or the like can be used, and general cylinders and screws of the extruder can be used. In addition, the twin screw extruder can be used with either two parallel shafts or a conical type with screw shafts crossed, and screw flight meshing type, non-meshing type, screw rotation in the same direction Can be used either in a different direction or in a different direction. In the case of a single-screw extruder, various screw designs such as a dull image type, rotor type, flute mixing type, etc. can be used as a mixing part, and even a shape without these mixing parts can be melted and formed into a sheet. . In the twin-screw extruder, a kneading disk, a rotor segment, a reverse screw flight, or the like may be arranged as a mixing unit, but a full flight screw without these can also be achieved. The cylinder can be either a vent type or a no vent type. As for the joining and film formation of the skin layer and the adhesive layer, there can be used a method in which the melted sheet discharged after flowing into a flat die (T die) after being joined by a feed block is taken out while being cooled. As the flat die, a T-type manifold die, a fish tail die, a coat hanger die, a screw die, or the like can be used. Also, a method of discharging a molten sheet by flowing into a multi-manifold die, a method of discharging from an inflation die, or the like can be used. The material temperature is preferably in the range of 130 to 280 ° C. at the time of coextrusion molding, but if the temperature is below this range, the melting becomes insufficient, and fish eyes are generated in the sheet, Interlayer adhesion may be insufficient. Further, when the temperature is higher than this range, there is a possibility that the sheet is colored or decomposed gas is generated due to thermal decomposition of the resin of each layer. A more preferable range of temperature is 180 to 250 ° C. Moreover, in the case of manufacture by such coextrusion, it can adjust within the said thickness range by adjusting the discharge speed of the material from an extruder. The discharge speed is adjusted by adjusting the screw speed in a single-screw extruder. In the case of a twin-screw extruder, the feed speed of the raw material charged into the extruder is adjusted by a feeder, and the screw speed of the extruder is further adjusted. This can be achieved by adjusting the rotational speed of the gear pump.

(Base material layer)
In the multilayer sheet for skin material, at least one base material layer selected from foamed polypropylene and polypropylene is adhered to the adhesive layer side (that is, the surface of the adhesive layer opposite to the surface in contact with the skin layer). May be. In FIG. 2, an example at the time of laminating | stacking the base material layer 4 on the surface on the opposite side to the skin layer 1 of the contact bonding layer 2 of the multilayer sheet 3 for skin materials is shown. The method for adhering the base material layer to the adhesive layer can be carried out according to the method for producing the multilayer sheet. Multi-layering with a foamed polypropylene layer is preferably a heat laminating method, that is, pressurizing a pre-formed multilayer sheet of this embodiment and a foamed polypropylene layer sheet at a temperature range of 130 to 280 ° C. using a roll or a press method. A method of bonding is adopted. In this case, good heat sealability of the base material layer and the adhesive layer is important. In addition, a coextrusion method and various laminating methods are preferably employed for multilayering with the polypropylene layer. When the base material polypropylene is not a sheet or film but a molded body, a film insert molding method, an in-mold molding method or the like that involves injection molding of the base material layer, or a TOM molding method on the base material layer Is also applicable. In this case as well, good heat sealability of the base material layer and the adhesive layer is important. As for TOM molding (Three Dimension Overlay Method), the molding method and molding equipment have been developed and provided by Fuse Vacuum Co., Ltd., and details are described in the literature, Color Material Association Vol. 79 (2006) ) No. 12, 561-566.

[Skin material]
A skin material is a member used so that the surface of various components may be covered. Since the skin material according to the present embodiment is formed using the above-described multilayer sheet for skin material, the skin material is excellent in softness, scratch resistance, oil resistance, and texture retention. Therefore, it can be suitably used as a skin material that covers the surfaces of various automobiles, furniture, indoor interiors, parts such as robots. The shape of the skin material is not particularly limited, and is usually in the form of a sheet or film.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these.
[material]
The raw material resins and production methods used in Examples and Comparative Examples are as follows.
(Skin layer)
The material and manufacturing method of the skin layer are as follows.
<Cross copolymer>
The following cross copolymers 1 to 3 were used. These cross copolymers were produced by the production methods of Examples or Comparative Examples described in International Publication No. 2000/37517, International Publication No. 2007/139116, and Japanese Patent Application Laid-Open No. 2009-12092. Similarly, it was determined by the method described in these publications. In other words, the composition in the cross-copolymer or ethylene-aromatic vinyl compound-aromatic polyene copolymer, ie, the content of ethylene, aromatic vinyl compound or aromatic vinyl compound polymer is determined by ¹ H-NMR (proton NMR). The content of aromatic polyene in the ethylene-aromatic vinyl compound-aromatic polyene copolymer was determined from the amount of aromatic polyene charged at the time of polymerization and gas chromatographic analysis of the polymerization solution sampled after completion of coordination polymerization. It calculated by calculating | requiring the amount of aromatic polyene used for superposition | polymerization from the difference of the amount of unreacted aromatic polyene, and comparing with the amount of the copolymer obtained by superposition | 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.
The styrene content, divinylbenzene content, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) of the ethylene-styrene-divinylbenzene copolymer used to define the cross copolymer, the cross copolymer The ethylene-styrene-divinylbenzene copolymer content, polystyrene chain weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) are shown.

Cross copolymer 1
-Ethylene-styrene-divinylbenzene copolymer having a styrene content of 25 mol%, a divinylbenzene content of 0.05 mol%, a weight average molecular weight of 142,000, a molecular weight distribution of 2.3,
-Content of ethylene-styrene-divinylbenzene copolymer: 82% by mass,
-Weight average molecular weight of polystyrene chain 30000, molecular weight distribution 1.3
・ A hardness 60
-The gel content was below the lower limit of detection (0.05 mass%).
・ MFR 3.7g / 10min (200 ℃, 49N)
Cross copolymer 2
-Styrene content of ethylene-styrene-divinylbenzene copolymer 25 mol%, divinylbenzene content 0.06 mol%, weight average molecular weight 130,000, molecular weight distribution 2.5,
-Content of ethylene-styrene-divinylbenzene copolymer: 76% by mass,
-Weight average molecular weight of polystyrene chain 30000, molecular weight distribution 1.2
・ A hardness 70
-The gel content was below the lower limit of detection (0.05 mass%).
・ MFR 6.6 g / 10 min (200 ° C., 49 N)
Cross copolymer 3
An ethylene-styrene-divinylbenzene copolymer having a styrene content of 20 mol%, a divinylbenzene content of 0.04 mol%, a weight average molecular weight of 101,000, a molecular weight distribution of 2.2,
-Content of ethylene-styrene-divinylbenzene copolymer: 82% by mass,
-Weight average molecular weight of polystyrene chain 30000, molecular weight distribution 1.2
・ A hardness 60
-The gel content was below the lower limit of detection (0.05 mass%).
-MFR 7.8g / 10min (200 degreeC, 49N)
The gel content was determined according to ASTM-D2765-84. The hardness A was determined according to the durometer hardness test method of JIS K-7215 plastic under the condition of 23 ± 1 ° C. This hardness is an instantaneous value.

<Preparation of resin compound for skin layer>
Using a Brabender plastic coder (PL2000 model manufactured by Brabender), a cross copolymer and polyphenylene ether (PPE) (YPX-100L manufactured by Mitsubishi Engineering Plastics Co., Ltd.) are cross-copolymer 85: polyphenylene ether 15 ( In total mass, about 45 g was kneaded at 250 ° C., 100 rpm for 10 minutes to prepare a resin compound for a skin material. As an antioxidant, 0.1 parts by mass of hindered phenolic antioxidant Irganox 1076 (manufactured by BASF) was used.

<Production of resin sheet for skin layer>
A skin sheet (length 75 mm, width 25 mm, thickness 1.0 mm) as a skin layer is heated and pressed (temperature 200 ° C., time 5) using the cross copolymer shown in Table 1 or a resin compound for the skin layer. And a pressure of 50 kg / cm ² ).

(Adhesive layer)
The adhesive layer was produced using the following materials.
<Olefin resin>
Thermoplastic olefin resin (TPO): Prime TPO R110E (manufactured by Prime Polymer Co., Ltd.) was used as the polymerization type (reactor TPO).
As an ethylene-α-olefin copolymer (ethylene-octene copolymer), Engage 8003 (manufactured by Dow Chemical Co., Ltd.), octene content 26 mass%, density 0.885 g / cm ³ , 190 ° C., load 2.16 kg Is 1.0 g / 10 min. It was used.
As the polypropylene (PP), Prime Polypro J106G (manufactured by Prime Polymer Co., Ltd.) was used.

<Styrene resin>
Arneston CE003 (manufactured by Kuraray Plastics Co., Ltd.) was used as the thermoplastic styrene resin (TPS).
As hydrogenated styrene-diene block copolymer (SEBS), Tuftec H1053 (manufactured by Asahi Kasei Co., Ltd.) and polystyrene-poly (ethylene / propylene) block-polystyrene (SEPS) as Septon 2007 (manufactured by Kuraray Co., Ltd.) were used. .

<Preparation of resin compound for adhesive layer>
Using the materials shown in Table 1, compounds used for the adhesive layer were produced as follows. The kneading of SEBS and polypropylene, SEPS and polypropylene, ethylene-α olefin copolymer and polypropylene was carried out using a Brabender plastic coder (PL2000 model manufactured by Brabender) with the formulation shown in Table 1 (parts by mass). . A total of about 45 g of the raw materials were kneaded at 220 ° C. and a rotation speed of 100 rpm for 10 minutes to prepare an adhesive layer resin compound. As an antioxidant, 0.1 parts by mass of hindered phenolic antioxidant Irganox 1076 (manufactured by BASF) was used.

<Preparation of resin sheet for adhesive layer>
Using the above-mentioned olefin resin, styrene resin, or resin compound for adhesive layer, the resin sheet for adhesive layer (length 50 mm, width 25 mm, thickness 0.2 mm) is the same as the resin sheet for skin layer, Molding was performed by a hot press method (temperature 230 ° C., time 5 minutes, pressure 50 kg / cm ² ).

(Base material layer (underlayer of multilayer sheet for skin material))
The following was used for the base material layer.
<Foamed PP sheet>
TORAYPEF 10010 AP67 (manufactured by Toray Industries, Inc.) (thickness: 1.0 mm) was used.
<PP sheet>
A sheet having a thickness of 1.0 mm was molded by a hot press method (temperature 220 ° C., time 5 minutes, pressure 50 kg / cm ² ) using homopolypropylene and Prime Polypro J106G (manufactured by Prime Polymer Co., Ltd.).

(Examples 1 to 13, Comparative Examples 1 to 3: Production of multilayer sheet)
A cross-copolymer skin sheet (skin layer resin sheet) having the composition shown in Table 1 and an adhesive layer resin sheet are stacked and adhered, and are subjected to pressure bonding at 200 ° C., 1 MPa, 10 seconds by a hot press method. A multilayer sheet was prepared.

Further, the multilayer sheet composed of the resin sheet for the skin layer and the resin sheet for the adhesive layer and the foamed PP sheet (75 mm in length, 25 mm in width, 1.0 mm in thickness) are stacked and adhered, and 200 by a hot press method. A multilayer sheet containing a foamed PP sheet was prepared by pressure bonding at 10 ° C. for 10 seconds.

[Evaluation]
Evaluation was performed as follows. The results are shown in Table 1.
<Peel test>
Using a multilayer sheet (length 75 mm, width 25 mm, thickness 1.0 mm) produced using the multilayer sheet containing the foamed PP sheet obtained in the examples and comparative examples, a part of the skin sheet having no adhesive layer The foamed PP sheet was chucked, and the 180 ° peel strength was measured at 23 ° C. and 50% humidity with a Shimadzu AGS-100D type tensile tester at a tensile rate of 100 mm / min.
In Table 1, “Peeling mode” indicates the peeling state. For example, “foamed PP material breakage” indicates that the foamed PP sheet is broken and peeled off.

<Measurement of viscoelasticity of resin sheet for adhesive layer: storage elastic modulus>
A film having a thickness of about 0.3 mm was produced by the hot press method (temperature 230 ° C., time 5 minutes, pressure 50 kg / cm ² ) in the same manner as the adhesive layer resin sheets used in Examples and Comparative Examples. A sample for measurement (8 mm x 50 mm) is cut out from this film, and measured using a dynamic viscoelasticity measuring device (Rheometrics RSA-III) at a frequency of 1 Hz and a temperature range of -50 ° C to 200 ° C and stored. The elastic modulus E ′ was determined. Other main measurement parameters related to the measurement are as follows.

Measuring frequency 1Hz
Temperature rising rate 4 ° C / min Sample measurement length 10mm
Initial Static Force = 5.0 [g]
AutoTension Sensitivity = 1.0 [g]
Max Automation Rate = 0.033 [mm / s]
Max Applied Strain = 1.5 [%]
Min Allowed Force = 1.0 [g]

The results of the peel test and the value of the storage elastic modulus (E ′) of the adhesive layer sheet are shown in Table 1. The multilayer sheet for skin material having the skin layer mainly composed of the cross-copolymer used in the examples and the adhesive layer satisfying a predetermined condition is bonded to the foamed PP or PP base sheet with high strength. In addition, the adhesive layer is soft at room temperature and has high heat resistance, and this multilayer sheet is suitable as a soft skin material. In addition, in the notation of the storage elastic modulus (E ′) in Table 1, for example, 3.6E + 07 Pa indicates 3.6 × 10 ⁷ Pa.

1: skin layer 2: adhesive layer 3: multilayer sheet for skin material 4: base material layer

Claims

A multilayer sheet for a skin material, comprising: a skin layer mainly composed of a cross copolymer; and an adhesive layer satisfying the following conditions (A) and (B) on one surface of the skin layer.
(A) The adhesive layer contains at least one resin selected from a thermoplastic olefin resin (TPO), a thermoplastic styrene resin (TPS), and a hydrogenated styrene-diene block copolymer.
(B) The storage elastic modulus at 25 ° C. of the adhesive layer is 5 × 10 8 Pa or less, and the storage elastic modulus at 125 ° C. is 5 × 10 5 Pa or more.
The cross copolymer has a structure in which an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain are bonded via an aromatic polyene monomer unit, and The multilayer sheet for skin material according to claim 1, wherein the following conditions (1) to (3) are satisfied.
(1) The content of the aromatic vinyl compound monomer unit of the ethylene-aromatic vinyl compound-aromatic polyene copolymer is 5 mol% or more and 40 mol% or less, and the content of the aromatic polyene monomer unit is 0.01 More than mol% and less than 0.2 mol%, the remainder is ethylene monomer units.
(2) The ethylene-aromatic vinyl compound-aromatic polyene copolymer has a weight average molecular weight of 50,000 to 300,000 and a molecular weight distribution (Mw / Mn) of 1.8 to 6.
(3) The content of the ethylene-aromatic vinyl compound-aromatic polyene copolymer contained in the cross copolymer is 40% by mass or more and 90% by mass or less.
The multilayer sheet for a skin material according to claim 1 or 2, wherein the cross copolymer is a graft-through copolymer of an ethylene-aromatic vinyl compound-aromatic polyene copolymer chain and an aromatic vinyl compound polymer chain.
The one or more types of base material layers selected from a foaming polypropylene and a polypropylene are further laminated | stacked on the surface on the opposite side to the surface which contact | connects the skin layer of an contact bonding layer. Multi-layer sheet for skin material.
The multilayer sheet for skin material according to any one of claims 1 to 4, which is for film insert molding, in-mold molding or TOM molding.
The multilayer sheet for a skin material according to any one of claims 1 to 5, wherein the cross-copolymer satisfies all of the following conditions (4) to (7):
(4) By 1 H-NMR measurement, peaks attributed to the ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer were observed, and the aromatic vinyl compound in the ethylene-aromatic vinyl compound copolymer was observed. The content is 5 to 40 mol%, the content of the ethylene-aromatic vinyl copolymer component contained is in the range of 40 to 90% by mass,
(5) The ethylene-aromatic vinyl compound copolymer and aromatic vinyl compound polymer contained have a bond,
(6) MFR (200 ° C., weight 49 N) is in the range of 0.05 to 50 g / 10 minutes,
(7) The gel content is 0.2% by mass or less.
A skin material formed using the multilayer sheet for a skin material according to any one of claims 1 to 6.