KR20190034495A - The laminate - Google Patents

Abstract

A laminate of a polyolefin resin foam (A) and a skin material (B), wherein the polyolefin resin foam (A) comprises a polyolefin resin foam (A) (a1) of 30% by mass or more and 60% by mass or less, the polyethylene resin (a2) of 1% by mass or more and 20% by mass or less, and the thermoplastic elastomer resin (a3) This makes it possible to promote easy cleansing of the airbag in a range from a low temperature to a high temperature region and to prevent the airbag from being separated from a skin material or a part of the foam And the appearance defect that the skin layer and the foam layer are peeled off do not occur, and the characteristic is particularly exhibited in the low temperature region.

Description

The laminate

TECHNICAL FIELD The present invention relates to a laminated body of an epidermis material and a polyolefin-based resin foam in an automobile interior material such as an instrument panel and a door panel.

The laminate composed of the skin material and the polyolefin resin foam is generally excellent in flexibility, heat resistance, heat insulation, light weight, and good design property and has been conventionally used for industrial materials such as heat insulating materials and flooring of pipe covers, And is used in automobile interior materials such as instrument panels. In particular, there is an increasing demand for the purpose of exhibiting the high-quality appearance and functionality of automotive interiors by imparting softness and softness to the laminate composed of the polyolefin resin foam and the feel of the softness.

In an automobile interior material such as an instrument panel and a door panel, in order to secure the safety of the driver and the crew when a car collides, the airbag is housed inside the cover body. When the cover is opened So that the air bag expands instantaneously. Therefore, there is a case where a hole drilling process or a groove forming process is performed on the relevant portion so that the air bag can easily expand and come out. However, since a structure in which holes and grooves are apparently displayed is not preferable, a resin material (base material) is covered with a laminate having a skin material and a polyolefin resin foam so as to prevent processing marks such as holes and grooves from being visible. So as to provide an automobile interior material having a more luxurious appearance.

In recent years, there has been a demand for a laminate for achieving a high degree of flexibility in appearance, a high-quality appearance, and a property of facilitating the destruction of the laminate made of the skin material and the polyolefin resin foam in the thickness direction.

However, in order to facilitate flexibility and breakage in the thickness direction of the laminate, flexibility is improved by lowering the thickness of the skin material and increasing the expansion ratio of the polyolefin-based resin foam, and the mechanical strength is lowered, However, the laminate is broken at the time of compression molding such as vacuum molding or low-pressure injection molding, which causes a problem in appearance. Further, by lowering the foaming magnification of the polyolefin-based resin foam, the mechanical strength is improved but the flexibility is lowered.

As a method for solving these problems, a laminate of a polyolefin resin foam in which the mixing ratio of a polypropylene resin, a polyethylene resin, and a thermoplastic elastomer resin is regulated, (See Patent Document 1) or a method in which a portion of a foam or a foam is scattered at the time of clearing the airbag or the appearance defect that the foam layer is peeled off (see Patent Document 1) Based resin and a thermoplastic elastomer-based raw material to obtain a crosslinked polyolefin-based resin foam which is excellent in heat resistance and flexibility and is given good design properties capable of secondary processing into a complicated shape; a thermoplastic polyolefin-based resin foam obtained by adding a thermoplastic polyurethane and an acrylic- , (Meth) acrylic acid esters of methyl methacrylate and alcohols having 2 to 8 carbon atoms A method has been proposed in which a sheet-shaped molding material in which calcium carbonate is mixed with a base material is integrated with a base material through a polyurethane foam or a polypropylene foam to obtain a product having a complicated, angular shape, (See Patent Document 2 and Patent Document 3).

As a skin material for an automobile airbag, a skin layer made of a thermoplastic resin layer, a two-layer structure made of a polyolefin foam layer, or a thermoplastic resin layer, a polyolefin foam layer, and a barrier layer made of polypropylene It has also been proposed to improve the appearance of the airbag housing portion and to facilitate the inflating of the airbag by using a layered structure in which a needle hole not visible to the naked eye is present in the skin material (see Patent Document 4).

Japanese Patent Application Laid-Open No. 2014-172307 Japanese Patent Application Laid-Open No. 2008-266589 Japanese Patent No. 3864330 Japanese Patent Application Laid-Open No. 10-44908

However, in a laminate of a polypropylene resin and a foamed article using a polyethylene resin or a thermoplastic elastomer resin, the polyolefin resin foam tends to be brittle and fractured in a low temperature region. Therefore, when the airbag is cleaved, There is a possibility that the airbag may not easily open because the possibility of scattering or the strength of the laminate temporarily increases.

In addition, it is not easy to visually perceive the skin material with a pinhole. If the pinhole is enlarged, it becomes a cosmetic problem. If it is too small, the effect may be limited.

An object of the present invention is to promote ease of opening of an airbag in a range from a low temperature to a high temperature region because the touch panel feels good in softness and feeling of softness, such as an instrument panel and a door panel.

It is another object of the present invention to solve the problem of scattering a part of the skin material or the foam at the time of opening the airbag and the appearance defect of peeling the skin layer and the foam layer.

In order to achieve the above object, the present invention has the following configuration.

The polyolefin resin foam (A) for use in the laminate of the present invention contains 30 mass% or more and 60 mass% or less of the polypropylene resin (a1) and 1 mass% or less of the polyethylene resin (a2) in 100 mass% By mass to 20% by mass, and 30% by mass or more of the thermoplastic elastomer resin (a3).

According to a preferred embodiment of the laminate of the present invention, the tensile elongation of the laminate is 30% or more under the temperature environment at -35 캜.

According to a preferred embodiment of the laminate of the present invention, the laminate is a laminate of the polyolefin resin foam (A) and the skin material (B), and the polyolefin resin foam (A) A peak exists in a range of 100 DEG C or more and 130 DEG C or less and 145 DEG C or more,

The skin material (B) has at least one in an area having an endothermic peak by differential scanning calorimetry (DSC) of not less than 95 ° C and not more than 110 ° C, and in each area not less than 130 ° C and not more than 160 ° C.

A preferred embodiment of the laminate of the present invention is for automobile interior materials.

When the laminate of the present invention is used as an automobile interior material on which a resin base material having an airbag housing structure is mounted, that is, in an instrument panel, a door panel, or the like, the laminate is excellent in softness And the airbag can facilitate easy cleavage in a range from a low temperature to a high temperature region.

In addition, at the time of airbag clearance, there is no problem of scattering of a part of the skin material or the foam, appearance failure of the skin layer and the foam layer being peeled off, and particularly in the low temperature region.

Hereinafter, the present invention will be described in detail.

The present invention relates to a laminated body of a polyolefin resin foam (A) and a skin material (B), wherein a polyolefin resin foam (A) is a laminate of 100% by mass of a polyolefin resin constituting the polyolefin resin foam (A) (A2) and 30% by mass or more of a thermoplastic elastomer resin (a3), wherein the polypropylene resin (a1) is 30 mass% or more and 60 mass% or less, and the polyethylene resin (a2) is 1 mass% or more and 20 mass% or less.

(A1) is contained in an amount of 30% by mass or more and 60% by mass or less, the polyethylene resin (a2) is contained in an amount of 1% by mass or more and 20% by mass or less and the thermoplastic elastomeric resin (a3) is contained in 100% by mass of a polyolefin- If it is contained in an amount of 30% by mass or more, it has an excellent tactile sensation of feeling flexibility and softness when it comes in contact with the laminate. Particularly in the low temperature region, It is possible to prevent appearance defects such as peeling of the foam layer from occurring.

The polyolefin resin foam (A) used in the laminate of the present invention is required to be composed of at least a polypropylene resin (a1), a polyethylene resin (a2) and a thermoplastic elastomer resin (a3).

Examples of the polypropylene resin (a1) include homopolypropylene, an ethylene-propylene random copolymer and an ethylene-propylene block copolymer. If necessary, a copolymer of a propylene monomer and another copolymerizable monomer may be used . The polypropylene resin (a1) may be used alone or in combination of two or more. The polymerization method of the polypropylene resin (a1) is not particularly limited and may be any one of a high-pressure method, a slurry method, a solution method and a gas phase method. The polymerization catalyst may also be a chitosan catalyst, And the catalyst is not particularly limited.

Wherein the polypropylene resin (a1) has an ethylene-propylene random copolymer and an ethylene-propylene random block copolymer having a melting point of at least 135 캜 and less than 160 캜 and an MFR (230 캜) of at least 0.5 g / 10 min and less than 5.0 g / , The ethylene content in the polypropylene resin (a1) is from 1% by mass or more to less than 15% by mass or the melting point is from 150 占 폚 to 170 占 폚, the MFR (230 占 폚) Propylene block copolymer or homopolypropylene having an ethylene content of 1 mass% or more and less than 15 mass% is particularly preferably used. Here, the "block" of the ethylene-propylene random block copolymer and the ethylene-propylene block copolymer means that the ethylene-propylene random copolymer or the homo-polypropylene is mixed with the ethylene-propylene rubber. In general, Lt; RTI ID = 0.0 > and / or < / RTI >

Examples of the polyethylene resin (a2) include high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer , And if necessary, a copolymer of an ethylene monomer and another copolymerizable monomer may be used. The polyethylene-based resin (a2) may be used alone or in combination of two or more. The polymerization method of these polypropylene type resins is not particularly limited and may be any of a high-pressure method, a slurry method, a solution method and a gas-phase method, and the polymerization catalyst is not particularly limited such as a chitosan catalyst or a metallocene catalyst .

The polyethylene resin (a2) preferably has a density of 890 to 950 kg / m 3 and an MFR (190 캜) of 1 g / 10 min or more and less than 15 g / 10 min. Among these, the density is preferably 920 to 940 kg / 190 占 폚) of 2 g / 10 min to 10 g / 10min and a melting point of 100 占 폚 or higher but lower than 130 占 폚 are particularly preferably used.

Examples of the thermoplastic elastomer resin (a3) include thermoplastic elastomers such as polystyrene thermoplastic elastomer (SBC, TPS), polyolefin thermoplastic elastomer (TPO), vinyl chloride thermoplastic elastomer (TPVC), polyurethane thermoplastic elastomer (TPU), polyester thermoplastic elastomer (TPEE), a thermoplastic elastomer (TPAE), a polybutadiene thermoplastic elastomer, a hydrogenated styrene butadiene rubber (HSBR), a styrene ethylene butylene-olefin crystal block polymer (SEBC), an olefin Crystalline block copolymers such as ethylene-butylene-olefin crystal block polymer (CEBC), styrene-ethylene butylene-styrene block polymer (SEBS) and olefin block polymer (OBC), polyolefin-vinyl type graft copolymers, Amide-based graft copolymers, polyolefin-acrylic graft copolymers, polyolefin-cyclodextrin-based grains Agent such as co-grafting of the polymer agent and the copolymer, and particularly preferably is an olefin block copolymer (OBC) or a polyolefin thermoplastic elastomer (TPO). Among these, it is preferable that both of heat resistance and flexibility are high, and from this viewpoint, olefin block polymer (OBC) is particularly preferable. These thermoplastic elastomer resin (a3) may be blended with at least one kind or at least two kinds. The polymerization method of the thermoplastic elastomer resin (a3) is not particularly limited and may be any one of a high-pressure method, a slurry method, a solution method and a gas-phase method, and a polymerization catalyst such as a chitosan catalyst or a metallocene catalyst But is not limited thereto.

The thermoplastic elastomer resin (a3) has a melting point in the range of 150 占 폚 or more and a crystal melting energy of less than 30 J / g from the viewpoint of excellent heat resistance and moldability. If the melting point is lower than 150 ° C, there is a possibility that the heat resistance obtained can not be sufficiently obtained. If the crystal melting energy is 30 J / g or more, crystallinity is high and sufficient flexibility may not be obtained. More preferably, the melting point is 160 DEG C or more and the crystal melting energy is less than 25 J / g. Further, a crystallization temperature of 50 DEG C or higher is preferably used. More preferably 60 DEG C or more. If the crystallization temperature is less than 50 캜, there is a possibility that the cycle time at the time of molding the foam can not be shortened.

The glass transition temperature of the thermoplastic elastomer resin (a3) is preferably less than -20 占 폚, more preferably less than -30 占 폚, and most preferably less than -40 占 폚. When the glass transition temperature is -40 占 폚 or higher, desired flexibility may not be obtained, and there is a possibility that the present invention may adversely affect the airbag deployment characteristics at low temperatures.

The thermoplastic elastomer resin (a3) preferably has a density of 850 to 920 kg / m 3 and an MFR (230 ° C) of 1 g / 10 min or more and less than 15 g / 10 min. Among these, the density is preferably 860 to 910 kg / , And an MFR (230 占 폚) of 5 g / 10 min or more and less than 10 g / 10 min are particularly preferably used. Examples of commercially available products of the thermoplastic elastomer resin (a3) used in the present invention include Mitsui Chemicals, Incorporated "Tafmer" PN-3560 as the olefin block polymer (OBC), polyolefin thermoplastic elastomer (TPO) include "TPO" (registered trademark) M142E manufactured by Prime Polymer.

The polyolefin resin foam (A) used in the laminate of the present invention may be mixed with other thermoplastic resin so long as the effect of the invention is not impaired. Examples of the thermoplastic resin include conventionally known polyesters, polyamides, polylactic acid, polyethers, polyvinyl chloride, polyurethane, and polystyrene.

In the polyolefin-based resin foam (A) used in the laminate of the present invention, within the range of not impairing the effect of the present invention, antioxidants such as phenol type, phosphorus type, amine type and sulfur type, Fillers such as talc, flame retardants such as bromine and phosphorus, flame retarding additives such as antimony trioxide, antistatic agents, lubricants, pigments, and additives for polyolefins such as polytetrafluoroethylene.

The polyolefin-based resin foam used in the laminate of the present invention is produced by mixing a blending agent capable of generating a gas into a mixture of polyolefin-based resins. As the method for producing the same, a mixture of a polyolefin- An atmospheric-pressure foaming method in which a foaming agent is added and melt-kneaded, and foaming is carried out by atmospheric pressure heating; an extrusion foaming method in which a pyrolytic chemical foaming agent is heated and decomposed in an extruder and extruded under high pressure; And a method such as an extrusion foaming method in which a gas or a solvent to be vaporized is melted and mixed in an extruder and foamed while being extruded under a high pressure.

The pyrolytic chemical foaming agent used herein is a chemical foaming agent which decomposes by heat and releases gas, and examples thereof include azodicarbonamide, N, N'-dinitrosopentamethylenetetramine, P, P'-oxybenzene Organic foaming agents such as sulfonyl hydrazide, and inorganic foaming agents such as sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and calcium azide.

The foaming agents may be used alone or in combination of two or more. An atmospheric pressure foaming method using azodicarbonamide as a foaming agent is routinely used in order to obtain a foam having high flexibility and high moldability and a high surface smoothness.

The polyolefin-based resin foam (A) used in the laminate of the present invention has a thickness of 0.50 mm or more and 5.0 mm or less. When the laminate of the present invention is used as an automobile interior material, the thickness of the polyolefin-based resin foam is preferably 1.0 mm or more and 4.0 mm or less, and in consideration of promoting breakage in a low-temperature environment of -40 ° C to -10 ° C, A more preferable range is from 2.0 mm to 3.0 mm.

The polyolefin-based resin foam used in the laminate of the present invention preferably has an apparent density in the range of 30 kg / m 3 to 150 kg / m 3 from the viewpoint of excellent moldability and flexibility, , The more preferred embodiment is in the range of 50 kg / m 3 to 100 kg / m 3.

The polyolefin-based resin foam used in the laminate of the present invention may be any of a crosslinked resin foam (referred to as crosslinked foam) and a non-crosslinked resin foam (referred to as a non-crosslinked foam) Select it. However, a cross-linked foam is preferable as the polyolefin-based resin foam in that it has smoothness on the surface of the resin foam, excellent appearance of the laminate, and is not easily broken at the time of molding, .

The method for making the polyolefin-based resin foam (A) into a crosslinked foam is not particularly limited. Examples of the method for obtaining a crosslinked foam include a chemical crosslinking method in which a crosslinking agent having a chemical structure such as a silane group, a peroxide, a hydroxyl group, an amide group or an ester group is chemically crosslinked by incorporating into a raw material, And a radiation crosslinking method of crosslinking by radiating a ray,? -Ray, and ultraviolet rays to a polyolefin-based resin. From the standpoint of promoting the destruction of the laminate in a low-temperature environment of -40 ° C to -10 ° C by making the cells of the foam uniform, and the appearance of the laminate to be excellent by smoothing the surface appearance of the foam, In order to make the crosslinked foam (A) a crosslinked foam, radiation crosslinking by electron beams is preferred.

Further, in the polyolefin-based resin foam (A) used in the laminate of the present invention, when it is difficult to construct a crosslinked structure in the electron beam crosslinking, the crosslinking aid is contained in the raw material for producing the polyolefin- based resin foam (A) Thereby obtaining a crosslinked foamed product by electron beam. The crosslinking aid is not particularly limited, but it is preferable to use a polyfunctional monomer. Examples of the multifunctional monomer include divinylbenzene, trimethylolpropane trimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, Trimellitic acid triallyl ester, triallyl isocyanurate, ethylvinylbenzene and the like can be used. These multifunctional monomers may be used alone or in combination of two or more.

When the polyolefin resin foam (A) used in the laminate of the present invention is crosslinked, that is, when the foam of the present invention is a crosslinked foam, the gel fraction showing the crosslinked state is preferably 20% or more and 65% or less , And more preferably in the range of 30% or more and 50% or less. When the gel fraction is less than 20%, gas of the foaming agent scatters from the surface during foaming, making it difficult to obtain a product having a desired expansion ratio. On the other hand, when the gel fraction exceeds 65%, excessive crosslinking occurs, There are cases where it is difficult to obtain a product and mechanical strength such as elongation at break is reduced and moldability is lowered in some cases.

The polyolefin-based resin foam (A) to be used in the laminate of the present invention is preferably an index having a 25% compression hardness of 30 kPa or more and 120 kPa or less as an index showing flexibility, more preferably 50 kPa or more and 100 kPa or less.

The polyolefin resin foam (A) used in the laminate of the present invention preferably has two or more endothermic peaks in a differential scanning calorimetry analysis. Concretely, it is preferable that the endothermic peak by the differential scanning calorimeter (DSC) is present at 100 ° C or more and 130 ° C or less and 145 ° C or more. More preferably, the first endothermic peak is at least 110 캜 and less than 125 캜, the second endothermic peak is at least 150 캜, and most preferably at least 155 캜. When the first endothermic peak is 130 ° C or higher, the softening temperature at the time of molding the laminate becomes too high, so that the molding cycle may become excessively long. When the second endothermic peak is lower than 145 ° C, The heat resistance tends to be inadequate in the current state where there is a tendency to increase the heating rate for raising.

The total crystalline melting energy per unit mass in the differential scanning calorimetry of the polyolefin-based resin foam (A) used in the laminate of the present invention is preferably less than 80 J / g. When it is 80 J / g or more, there are many crystal components, so that there is a possibility that the flexibility to be achieved by the present invention is not sufficiently obtained. More preferably less than 70 J / g.

It is preferable that the crystalline melting energy per unit mass of the polyolefin-based resin foam (A) used in the laminate of the present invention is not lower than 20 J / g at 145 캜 or higher. If it is 20 J / g or more, a large amount of propylene resin may be contained. In this case, there is a possibility that sufficient flexibility for the purpose of the present invention may not be obtained.

The heat shrinkage ratio of the polyolefin-based resin foam (A) used in the laminate of the present invention after 10 minutes at 180 ° C is preferably less than 40%. If it is 40% or more, it shrinks at the time of vacuum molding. Therefore, if a molded body having a predetermined size is to be obtained, a larger amount of material is required, and the yield is deteriorated, and more skin material becomes necessary and economically disadvantageous.

The molded drawing ratio of the polyolefin-based resin foam (A) used in the laminate of the present invention is preferably 0.4 or more and less than 0.8. If it is less than 0.4, there is no sufficient moldability and cracking may occur at the time of shaping. On the other hand, if it is 0.8 or more, there is a possibility that the laminate is separated from the skin material, which is not preferable. More preferably 0.5 or more and less than 0.7.

The polyolefin-based resin foam (A) used in the laminate of the present invention preferably has a closed-cell structure. In the case of a foam having a closed cell structure, it is possible to form the foam into a complicated shape by sufficiently blowing air by vacuum molding for its structure. Further, the bubbles are preferably fine and uniform because the surface of the foamed product or the molded product formed from the foam is smooth.

It is preferable that the polyolefin-based resin foam (A) used in the laminate of the present invention can be produced in the form of a long sheet. It is possible to supply a large amount at a low cost by making it into a long sheet type.

The thermoplastic resin constituting the skin material (B) constituting the laminate of the present invention is not particularly limited. Examples of the thermoplastic resin constituting the skin material (B) include thermoplastic resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer A thermoplastic polyolefin elastomer (TPO) containing an elastomer component such as ethylene-propylene rubber (EBA) and ethylene-propylene rubber, a vinyl resin such as polyvinyl chloride and polyvinylidene chloride, a polyurethane resin, a polystyrene- Resins, and copolymers composed of monomers copolymerizable with these resins. The thermoplastic resin constituting these skin materials (B) may be mixed with at least one kind or two or more kinds.

The thermoplastic resin constituting the skin material (B) preferably has at least an endothermic peak by differential scanning calorimetry in a range of 95 ° C to 110 ° C and at least 130 ° C to 155 ° C. It is preferable that the skin material (B) has at least an endothermic peak by differential scanning calorimetry in a region of 95 ° C or more and 110 ° C or less and in each region of 130 ° C or more and 155 ° C or less.

For the purpose of improving workability and appearance, an inorganic filler, an antioxidant, a hydrocarbon-based oil, etc. may be added. Particularly, when the skin material (B) contains a block copolymer elastomer having a polyolefin-based hard segment and a polyolefin-based soft segment, the polyolefin-based resin foam (for example, A) is simplified and also flexibility is ensured when it is contacted.

The thickness of the skin material (B) constituting the laminate of the present invention is not particularly limited and may be used by processing to a thickness according to the intended use. The thickness of the skin material (B) is preferably in the range of 0.1 mm to 1.5 mm. The thickness of the skin material (B) is preferably 0.3 mm or more and 0.6 mm or less in consideration of promoting breakage in a low temperature environment of -40 占 폚 to -10 占 폚.

The method of laminating the polyolefin resin foam (A) and the skin material (B) of the present invention is not limited. The surface of the surface of the polyolefin resin foam (A) or the surface material (B) which is in contact with the adhesive agent is subjected to electric discharge machining to introduce hydroxyl groups on the surface thereof to improve the adhesiveness. As a known adhesive, a polyester- or urethane- There is a method in which a base adhesive or an emulsion base adhesive is applied to the polyolefin-based resin foam (A) and bonded. Specific examples of the adhesive include "Pandex T-5265" manufactured by Dainippon Ink And Chenicals, Inc., "Desmocall # 500" manufactured by Bayer AG, etc. . As another method, a hot-melt bonding method in which the polyolefin-based resin foam (A) and the skin material (B) are laminated by heating is suitably used.

The laminate of the present invention preferably has a tensile elongation of 30% or more under an environment of -35 占 폚. If the tensile elongation at -35 캜 of the laminate is less than 30%, the polyolefin-based resin foam (A) is scattered during cleavage of the airbag, which is not preferable. The tensile elongation when the polyolefin resin foam (A) and the skin material (B) were peeled off or peeled off from the material under the environment of -35 캜 of the laminate was measured in the longitudinal direction ) And in the direction perpendicular to the direction (hereinafter referred to as " TD " direction).

The laminate of the present invention preferably has a maximum peel strength of at least 20 N / 25 mm at the interface peeling between the polyolefin resin foam (A) and the skin material (B) or the material peeling peeling. When the maximum peel strength of interfacial peeling or material peeling peeling is less than 20 N / 25 mm, the polyolefin resin foam (A) and the skin material (B) are peeled off at the time of destruction, There is a possibility of causing a problem that one part of the foam material (A) or the skin material (B) is scattered. Particularly, in an automobile interior material on which an airbag is mounted, when the polyolefin-based resin foam (A) is peeled from the skin material (B) due to the impact that the airbag destroys the laminate, only the polyolefin-based resin foam (A) B) is not broken, and it is feared that the speed at which the airbag is cleared is slowed down. It is preferable that the maximum peel strength of the interface peel between the polyolefin resin foam (A) and the skin material (B) or the material peeling peel of the laminate is 25 N / 25 mm or more. The maximum peel strength of the interface peel between the polyolefin resin foam (A) and the skin material (B) or the material peeling peel of the laminate of the present invention is 20 N / 25 mm in both the MD and TD directions Or more.

The upper limit of the maximum peel strength between the polyolefin resin foam (A) and the skin material (B) of the present invention is not limited, but is preferably 150 N / 25 mm or less.

When the laminate of the present invention is used as an automobile interior material, the adhesive for bonding the laminate and the resin substrate is not particularly limited. For example, "Pandex T-5265" manufactured by Dainippon Ink and Chemicals, Inc., and "Desmocall # 500" manufactured by Bayer Co., Ltd. may be used as adhesives on the polyolefin resin foam side.

The difference in tensile elongation at low temperature between the polyolefin-based resin foam (A) used in the laminate of the present invention and the skin material is preferably less than 150%. , More preferably not less than 10% and less than 100%, and still more preferably not less than 25% and less than 80%. When the airbag is deployed at a low temperature in the case of 150% or more, the timing at which the foamed material and the skin material are broken is staggered, so that peeling at the interface occurs more severely and scattering of the foam is generated.

The automobile interior material made of the laminate of the present invention generally has at least three layers of a skin material (B), a polyolefin resin foam (A), and a resin material.

The composition (composition) of the resin base material used in the automobile interior material of the present invention is not particularly limited and may be selected from the group consisting of polypropylene resin, ABS resin, polycarbonate resin, talc, mica, wollastonite, glass beads, It is common to use a composite reinforced with an inorganic filler such as a fiber.

In the case of the automobile interior material comprising the laminate of the present invention, there is no limitation on the molding process. In general, the laminate of the polyolefin resin foam (A) and the skin material (B) is subjected to extrusion molding, vacuum molding, , Blow molding, or the like, a method of forming a molded article of a laminate in the form of an interior material, and bonding the polyolefin resin foam (A) and the resin substrate with an adhesive or a heat medium interposed therebetween. The molding may be performed by heat welding, vibration welding, ultrasonic welding, laser welding, or the like to a secondary shape according to necessity.

When the laminate of the present invention is laminated on a resin base material having an airbag function of an automobile interior material, in order to accelerate the cleansing of the airbag, a hole drilling machine or a laser processing machine is used so that the appearance of the skin material (B) Lt; / RTI > It is preferable that the holes in the resin base material and the polyolefin-based resin foam (A) are punched in the direction from the resin base material side to the skin material (B) side so that the air bag is more easily separated.

Next, the method for producing the foam of the present invention will be described.

A thermally decomposable foaming agent such as azodicarbonamide is further added to the polypropylene resin (a1), the polyethylene resin (a2) and the thermoplastic elastomer resin (a3) and uniformly mixed using a mixing device such as a Henschel mixer or a tumbler Mix. Thereafter, melt kneading is uniformly performed at a temperature lower than the decomposition temperature of the thermally decomposable foaming agent by using a melt kneading machine such as an extruder or a pressurized kneader, and the resultant is molded into a sheet shape by a T- And crosslinked.

Next, the obtained sheet-like material is heated to a temperature not lower than the decomposition temperature of the thermally decomposable foaming agent and foamed by the gas generated by the decomposition by a method of putting the obtained sheet-like material on a bath of a fruit or a method of introducing into the atmosphere such as hot air, (A) of the polyolefin-based resin can be obtained.

Next, the method for producing the skin material of the present invention will be described.

The thermoplastic resin constituting the skin material (B) is melted and kneaded using a melt kneading machine such as an extruder or a pressurized kneader, and molded into a sheet form by a T-type kneading or calender roll, and controlled to have a predetermined thickness. The obtained sheet having a predetermined thickness can be air-cooled or water-cooled to obtain a skin material (B).

Next, a method for producing the laminate of the present invention will be described.

(A) obtained by the method for producing a foam and the surface material (B) obtained by the method for producing a skin material are subjected to a temperature of -10 ° C to + 10 ° C relative to a maximum temperature obtained from the endothermic peak Layer structure of a three-layer structure by a heat-sealing method through a nip roll adjusted to a gap in the range of -0.3 mm to 1.5 mm than the sum of the thickness of the skin material (B) and the thickness of the polyolefin-based resin foam (A) I get a sieve.

<Examples>

The evaluation methods used in the following Examples and Comparative Examples are as follows.

(1) MFR of polyolefin-based resin:

The MFR of the polyolefin resin is determined in accordance with JIS K7210 (1999) "Annex B (Reference)" Test Method of Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Plastics-Thermoplastic Plastics " (A1) and the thermoplastic elastomer resin (a3) under conditions of a temperature of 190 占 폚, a load of 2.16 kgf, a polypropylene resin (a1), a temperature of 230 占 폚 and a load of 2.16 kgf (Melt indexer type F-B01, manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used as a melt-mass flow rate meter, and a manual cutting method was employed. And the weight of the resin was measured.

(2) Density of polyolefin-based resin:

The density of the polyolefin resin was measured in accordance with JIS K7112 (1999) &quot; Method of measuring density and specific gravity of plastic-nonfoamed plastic &quot;.

(3) Melting point, crystallization temperature and glass transition temperature of the resin constituting the polyolefin-based resin foam (A) and the skin material (B):

In the present invention, the melting point of the polyolefin-based resin is the maximum temperature obtained from the endothermic peak of the DSC curve obtained by taking the temperature in the longitudinal axis (J / g) and the longitudinal axis obtained by the differential scanning calorimetry. 2 mg of each sample was prepared using a differential scanning calorimeter (DSC: RDC 220-Robot DSC, manufactured by Seiko Denshi Kogyo Co., Ltd.) and measured under a nitrogen atmosphere. The measurement conditions are as follows: the sample is heated to a temperature of 200 ° C and melted, and then the exothermic peak obtained when the sample is cooled to a temperature of -100 ° C at a rate of 10 ° C / minute is the crystallization temperature; The glass transition temperature corresponds to the middle point. The temperature was raised therefrom at a rate of 10 ° C / minute, and the endothermic peak per unit mass was measured. The endothermic peak obtained at the second heating was defined as the melting point.

(4) Thickness of foam:

The thickness of the foam is a value measured in accordance with ISO1923 (1981) &quot; Method of measuring foam plastic and rubber-line dimensions. &Quot; Specifically, a foamed piece cut to a predetermined size is placed on a flat table using a dial gauge equipped with a circular measuring instrument having an area of 10 cm 2, and then the foam is brought into contact with the surface of the foam at a constant pressure.

(5) Apparent density of the foam:

The apparent density of the foam is a value measured and calculated in accordance with JIS K6767 (1999) &quot; foam plastic-polyethylene-test method &quot;. The thickness of the foam cut into 10 cm squares is measured, and the mass of the test piece is also weighed. The value obtained by the following formula is taken as the apparent density, and the unit is set to kg / m3.

(Kg / m 3) = {mass of test piece (kg) / area of test piece 0.01 (m 2) / thickness of test piece (m)}

(6) Gel fraction of the foam:

The foam is cut into about 0.5 mm square, and about 100 mg is weighed in units of 0.1 mg. Immersed in 200 ml of tetralin at 130 ° C for 3 hours, then naturally filtered with a 100 mesh stainless steel wire net, and the insoluble powder on the wire net is dried for one hour at 120 ° C. by a hot air oven. Then, it is cooled in a desiccator containing silica gel for 10 minutes, and the mass of the insoluble component is precisely weighed, and the gel fraction of the foam is calculated as a percentage according to the following formula.

Gel fraction (%) = {mass (mg) of insoluble fractions / mass (mg) of weighed foam)} 100

(7) 25% of the foam Compression hardness:

The 25% compression hardness of the foam is a value measured based on JIS K6767 (1999) &quot; foam plastic-polyethylene-test method &quot;. Specifically, the foam is cut into 50 mm 50 mm, and the thickness is 20 mm or more and 30 mm or less, and the initial thickness is measured. The sample was placed on a flat plate, compressed at a rate of 10 mm / min up to 25% of the initial thickness and stopped, and the load after 20 seconds was measured and the 25% compression hardness (kPa) was calculated by the following equation.

25% Compressive hardness (kPa) = 25% Compressive load after 20 seconds (N) / 25 (cm2) / 10

(8) Measurement method of the foam by differential scanning calorimetry:

In the present invention, the endothermic peak of the foam refers to the heat amount (J / g) in the vertical axis obtained by differential scanning calorimetry analysis and the peak of the endothermic side in the DSC curve obtained when the temperature is taken along the horizontal axis. Specifically, the bubbles of the foam were crushed by a mixing roll or the like in advance, and about 2 mg of the test piece was weighed and measured using a differential scanning calorimeter (DSC: RDC 220-Robot DSC manufactured by Seiko Denshi Kogyo Co., Ltd.) Lt; / RTI &gt; The measurement conditions are as follows: the sample is heated up to a temperature of 200 ° C and melted, then cooled to a temperature of -50 ° C at a rate of 10 ° C / minute, and then heated again at a rate of 10 ° C / minute to obtain a DSC curve. The peak that can be obtained from the DSC curve obtained at the second temperature rise is called an endothermic peak. The total crystalline melting energy is calculated by the DSC curve at this time and the area surrounded by the baseline. Further, the term endothermic per unit mass of 130 占 폚 or more means a portion surrounded by the DSC curve and the baseline divided by a line of 130 占 폚 and calculated by the area of the portion higher than this temperature.

(9) Method of Measuring Heat Shrinkage of Foam:

The measurement of the heat shrinkage ratio is carried out in accordance with JIS K6767 (1999) &quot; foamed plastic-polyethylene-test method &quot;. Specifically, the amount of decrease in the interval of the marks after standing for 10 minutes in a hot-air oven in which a test piece drawn with a 100 mm square is adjusted to 180 ° C is expressed as a percentage of the original interval between marks Value.

(10) Method of Measuring Molded Drawing Ratio of Foam:

When the foam is heated on a vertical cylindrical female mold (female mold) having a diameter D and depth H of the molding, the foam is not destroyed when the foam is straight-formed using a vacuum molding machine, and the H / D, respectively.

(11) Tensile test method of foam or skin material under high temperature and low temperature:

A sample of a test piece punched in a dumbbell-type mold 1 was placed in an environment of a thermostatic chamber for 6 minutes, at 160 占 폚 for a high temperature and at -20 占 폚 for a low temperature and then subjected to a test according to JIS K6767 (1999 ) A tensile test was carried out in accordance with &quot; foamed plastic-polyethylene-test method &quot;, and the maximum value of tensile strength and the value of tensile elongation at breakage were determined.

Device: Densilon UCT-500 (Orientech Corporation)

Tensile speed: 500 mm / min

(12) Tensile strength and elongation of the laminate at -35 캜:

A test piece sample of the laminate cut in both the MD and TD directions was placed in an environment of -35 占 폚 for 10 minutes and then subjected to a test at a test speed of 500 mm / min in accordance with JIS K6767 (1999) -Testing method &quot;, the maximum value of the tensile strength and the value of the tensile elongation at breakage were determined.

Device: Densilon UCT-500 (Orientech Corporation)

Tensile speed: 500 mm / min

The obtained tensile strength and tensile elongation are the average values obtained from the values measured two times.

(13) Maximum peel strength of the laminate

A test piece sample of a laminate cut in a size of 150 mm x 25 mm in both the MD and TD directions was peeled under the conditions of a tensile speed of 200 mm / min, a peeling angle of 180 deg., And a peeling distance of 80 mm in accordance with JIS Z 0237 (2009), the value of the maximum peel strength was obtained. The measurement temperature is 23 ° C and the humidity is 50% RH.

Device: Densilon UCT-500 (Orientech Corporation)

Tensile speed: 200 mm / min

The peel strength obtained is the maximum peel strength value within a peel distance of 80 mm and is an average value obtained from the values measured twice.

(14) Flexibility evaluation of laminate:

The stroke length when the laminate 100 × 100 mm was compressed from the skin material (B) side was evaluated in five steps as described below.

[test requirements]

Apparatus: Handy compression tester "KES-G5" manufactured by KATO TECH CO., LTD.

Measurement environment: 23 ℃

Measurement conditions: Stroke length (mm) when compressed by 1 kg

Compression speed: 1.5 mm / sec

5: 1.31 mm or more

4: 1.01 to 1.30 mm

3: 0.71 to 1.00 mm

2: 0.41 to 0.70 mm

1: Not more than 0.40 mm.

(15) Moldability evaluation of laminate

With respect to the evaluation of the formability of the laminate, the sensory evaluation indexes are shown below. More specifically, the cylindrical molding die of (10) was used to heat the laminate (upper surface of the skin material as the foam surface) until the surface temperature became 160 ° C, straight-mold it using a vacuum molding machine, The appearance, in particular, the surface of the skin material was observed to determine whether it was good or not. In addition, for the touch feeling, it was similarly judged whether or not the surface of the skin material side was good with a finger.

5: It has sufficient flexibility as a touch and excellent in appearance

4: Flexibility is retained as the feel, and there is no defects such as grooves as appearance,

3: There is no problem in appearance, but the feeling of flexibility is lowered, the feeling of bottom is felt, or the feeling is not a problem, but there are some apparent problems.

2: As for the feeling, either flexibility is not felt or a large defect occurs in appearance, and a remarkably poor state

1: Both the touch and the appearance are remarkably problematic, and the product can not stand as a product

(16) Tensile elongation comparison of skin material and foam in a laminate at low temperature

Evaluation was made in five steps from the values obtained when the tensile test of the skin material and the foam made in the step (11) and the average value of the tensile elongation in the MD direction and the TD direction at low temperature (-20 캜) were calculated by the following formulas Respectively. Indicators are shown below.

Average value (%) of low temperature tensile elongation of the skin material - average value (%) of low temperature tensile elongation of the foam material

5: Less than 200%

4: 200% or more and less than 230%

3: 230% or more and less than 260%

2: 260% or more and less than 290%

1: More than 290%.

(17) Overall evaluation

Flexibility evaluation, formability evaluation and low temperature tensile elongation comparison evaluation were evaluated based on the following indexes, and the results were evaluated as acceptable.

◎: The total is 13 or more

○: The total is 11 or more and less than 13

?: The total is more than 9 and less than 11

×: The total is less than 9

Resins used in Examples and Comparative Examples are as follows.

&Lt; Polypropylene resin (a1) >

PP1: Prime Polymer Manufacture "Prime Polypropylene" (registered trademark) J452HAP

Density: 900 kg / m 3, MFR (230 캜) = 3.5 g / 10 min, Melting point = 163 캜

PP2: "Novatech" (registered trademark) PP EG8B manufactured by Japan Polypropylene Corporation

Density: 900 kg / m 3, MFR (230 캜) = 0.8 g / 10 min, melting point = 140 캜

&Lt; Polyethylene-based resin (a2) >

PE1: Japanese polyethylene "NOVA TECH" (registered trademark) LL UJ960

Density: 935 kg / m 3, MFR (190 캜) = 5 g / 10 min, melting point = 126 캜

PE2: Japanese polyethylene "NOVA TECH" (registered trademark) LD LJ602

Density: 922 kg / m 3, MFR (190 캜) = 5.3 g / 10 min, melting point = 113 캜

&Lt; Thermoplastic elastomer resin (a3) >

TPE1: "Tafmer" (registered trademark) PN-3560 manufactured by Mitsui Chemicals,

Melting point = 160 占 폚, crystallization temperature = 60 占 폚, glass transition temperature = -25 占 폚, crystal melting energy = 23 J / g

TPE2: Prime polymer preparation "Prime TPO" (registered trademark) M142E

Melting point = 153 占 폚, crystallization temperature = 80 占 폚, glass transition temperature = -23 占 폚, crystal melting energy = 29 J / g

TPE3: "INFUSE " (registered trademark) 9107

Melting point = 121 占 폚, crystallization temperature = 95 占 폚, glass transition temperature = -62 占 폚, crystal melting energy = 15 J / g

TPE4: "Tafmer" (registered trademark) PN-2070 manufactured by Mitsui Chemicals,

Melting point = 140 占 폚, crystallization temperature = 62 占 폚, glass transition temperature = -23 占 폚, crystal melting energy = 23 J / g

Blowing agent: azodicarbonamide manufactured by EIWA CHEMICAL IND. CO., LTD. "Vinihole AC # R " (registered trademark)

Crosslinking aid: 55% divinylbenzene manufactured by Wako Pure Chemical Corporation

Antioxidant: "IRGANOX " (registered trademark) 1010 manufactured by BASF

[Examples 1 to 20], [Comparative Examples 1 to 10]

The foams prepared in Examples 1 to 20 and Comparative Examples 1 to 10 are as follows.

The polypropylene resin (a1), the polyethylene resin (a2), the thermoplastic elastomer resin (a3), the foaming agent, the crosslinking aid and the antioxidant shown in Table 1 were mixed at respective ratios using a Henschel mixer, At a temperature of 170 캜, and a polyolefin-based resin sheet having a predetermined thickness was prepared using a T-die. The thus obtained polyolefin-based resin sheet was irradiated with an electron beam having an accelerating voltage of 800 kV and a predetermined absorption dose from one side to obtain a crosslinked sheet. The crosslinked sheet was floated on a water bath at 220 ° C and heated from above by an infrared heater Lt; / RTI &gt; The foamed product was cooled with water at a temperature of 60 캜 and the surface of the foamed product was washed with water and dried to obtain a polyolefinic resin foamed product A having a thickness of 1.5 to 3.0 mm, an apparent density of 50 to 100 kg / m 3, and a gel fraction of 35 to 45% ) Was obtained.

The skin material (B) was produced as follows.

As the skin material (B), a thermoplastic polyolefin-based elastomer having an endothermic peak at 95 DEG C and 138 DEG C as a differential scanning calorimeter was used and melt-kneaded by an extruder to obtain a sheet having a thickness shown in Table 1 from the T-

The laminate was produced as follows.

The polyolefin-based resin foam (A) is obtained by heating the surface heated at the radial heater side at the time of foaming to 146 ° C to determine the roll gap as the sum of the thickness of the skin material (B) and the thickness of the polyolefin- , The heating surface side and the skin material (B) were thermally fused to form a laminate. Table 1 shows physical properties and evaluation conditions of the polyolefin resin foam (A), the skin material (B), and the laminate.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

&Lt; Industrial applicability >

The present invention is suitable for automobile interior materials such as instrument panels and door panels.

Claims (4)

As a laminated body of the polyolefin resin foam (A) and the skin material (B)
Wherein the polyolefin resin foam (A) contains 30% by mass or more and 60% by mass or less of the polypropylene resin (a1) or less than 60% by mass or less of the polyolefin resin (A) a2) of 1 mass% or more and 20 mass% or less, and 30 mass% or more of a thermoplastic elastomer resin (a3). The method according to claim 1,
Wherein a tensile elongation of the laminate composed of the skin material (B) and the polyolefin-based resin foam (A) is 30% or more under a temperature environment of -35 占 폚. 3. The method according to claim 1 or 2,
A laminate of a polyolefin resin foam (A) and a skin material (B)
The polyolefin-based resin foam (A) has an endothermic peak in a differential scanning calorimeter (DSC) of 100 占 폚 or more and 130 占 폚 or less and 145 占 폚 or more,
The skin material (B) has an endothermic peak in at least one differential scanning calorimeter (DSC) in each region of an endothermic peak by differential scanning calorimetry (DSC) of 95 ° C or more and 110 ° C or less and 130 ° C or more and 160 ° C or less Brass, laminate. 4. The method according to any one of claims 1 to 3,
A laminate for use as an automobile interior material.