JPH0752294A - Polyolefin resin laminate - Google Patents

Abstract

PURPOSE:To obtain laminate having a sheath layer in which residual offensive odor and a hue change are low by adhering a specific partially crosslinked thermoplastic elastomer layer to a polyolefin foam layer crosslinked emitting ionizing radiation. CONSTITUTION:Partially crosslinked thermoplastic elastomer (ER) is obtained by dynamically heat-treating composition containing 5-80wt.% of crystalline polypropylene, 95-20wt.% of olefin copolymer rubber; 0.015-0.045 pts.wt. of peroxide crosslinking agent and 0.2-2.0 pts.wt. of polyvalent crosslinking assistant to 100 pts.wt. of total sum of the both in an atmosphere containing 0.1% or less of oxygen concentration. The ER is fused to crosslinked polyolefin foam formed with a crosslinking structure by emitting ionizing radiation. A laminated obtained in this manner has low residual offensive odor, and generation of varnish on a sheath layer, deterioration of a hue are not almost recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin laminate comprising a skin layer made of a partially crosslinked thermoplastic elastomer and a polyolefin crosslinked foam layer. The present invention relates to a polyolefin resin laminate having a small change.

[0002]

2. Description of the Related Art Materials used for building materials, interior materials for automobiles, housings for household electric appliances, etc. are polyvinyl chloride layers, foam layers and, if necessary, laminates composed of resin base material layers, and polyolefin-based materials. A thermoplastic elastomer layer made of a partially cross-linked product of a resin and an olefin-based copolymer rubber, a foam layer, and a laminate made of a resin base material layer as necessary are used.

Among these laminates, those using a thermoplastic elastomer as the skin layer do not require an adhesive at the time of lamination and are excellent in flexibility and heat resistance, and are therefore widely used. Most of the thermoplastic elastomers are dynamically heat-treated using an organic peroxide to form a crosslinked structure.

Various proposals have hitherto been made regarding such a thermoplastic elastomer. For example
No. 53-34210 discloses a partially blended thermoplastic blend of a monoolefin copolymer rubber and a polyolefin plastic. Mono-olefin copolymer rubber is
Ethylene-propylene copolymer rubber (EPR) and ethylene-propylene-non-conjugated diene copolymer rubber (EPD)
M) and other elastomers, and polyolefin plastics such as polyethylene and polypropylene. Partial curing is also performed under dynamic conditions, that is, during melt kneading.

Japanese Examined Patent Publication No. 54-2662 discloses that 40 to 90 parts by weight of a monoolefin copolymer rubber, crystalline polypropylene and //
Or crystalline ethylene-propylene block copolymer 60-
Disclosed is a method for producing a thermoplastic elastomer, which comprises kneading 10 parts by weight and partially crosslinking in a molten state.

Further, Japanese Patent Publication No. 55-18448 discloses a blend of 25 to 85 parts by weight of a crystalline thermoplastic polyolefin resin and 75 to 15 parts by weight of a vulcanized monoolefin copolymer rubber, and 100 parts by weight of rubber. Disclosed is a thermoplastic elastomer-like composition containing 0 to 300 parts by weight of extender oil and the like.

A composition comprising a polyolefin resin and a partially cross-linked monoolefin copolymer rubber as described above has improved tensile properties, flexibility, rebound resilience, etc., but moldability and long-term heat stability. There is a problem that the sex is insufficient.

In order to solve such problems, 5 to 40% by weight of polyisobutylene and / or isobutylene-isoprene copolymer rubber, ethylene-propylene copolymer rubber and / or ethylene-propylene-non-conjugated diene A thermoplastic elastomer composition (Japanese Patent Publication No. 54-23702) comprising 30 to 90% by weight of the original copolymer rubber and 5 to 40% by weight of a polyolefin resin, and (a) a peroxide crosslinkable olefin copolymer rubber 90 to 40 parts by weight and (b) 10 to 60 parts by weight of peroxide decomposition type olefinic plastic ((a)
+ (B) is 100 parts by weight), and (c) non-peroxide type hydrocarbon-based rubber-like substance and / or (d) mineral oil-based softener
A partially crosslinked thermoplastic elastomer composition (Japanese Patent Publication No. 56-15741) obtained by dynamically heat treating a mixture of 100 parts by weight in the presence of an organic peroxide has been proposed. Incidentally, typically, the peroxide cross-linking olefin copolymer rubber (a) is ethylene-propylene copolymer rubber or ethylene-propylene-non-conjugated diene copolymer rubber, peroxide decomposition type olefin plastic (b) Is isotactic polypropylene, and the peroxide-non-crosslinked hydrocarbon-based rubber-like substance (c) is polyisobutylene or butyl rubber.

However, each of the above-mentioned compositions forms a crosslinked structure by using a large amount of a peroxide crosslinking agent, and the residual peroxide after crosslinking, peroxide decomposed products or polymer decomposed products, etc. Due to the influence, when the composition is formed into a sheet or the like, eyes and eyes are likely to occur, which causes a problem that the surface is roughened.

JP-B-1-14023 is obtained by dynamically heat-treating a polyolefin resin and 0.1 to 2 parts by weight of organic peroxide per 100 parts by weight of an object to be used for forming a thermoplastic elastomer. Disclosed is a laminate comprising a blended product of a partially crosslinked ethylene / α-olefin copolymer rubber and a surface-embossed thermoplastic elastomer layer, and a polyethylene or polypropylene foam layer. is doing.

However, even in this laminate, since the thermoplastic elastomer composition contains a large amount of peroxide crosslinking agent, it has the same problem as the above-mentioned composition. Therefore, when a sheet made of this thermoplastic elastomer composition is used as a skin material for a laminate with a polyethylene or polypropylene crosslinked foam, problems such as deterioration of hue due to oxidation and generation of odor occur. When used for building materials, interior materials for automobiles, housings for household electric appliances, etc., the problem of residual odor is particularly important.

[0012] Therefore, an object of the present invention is to provide a polyolefin resin laminate comprising an outer skin layer made of a partially crosslinked thermoplastic elastomer having a small residual odor and a change in hue and a polyolefin crosslinked foam layer.

[0013]

In view of the above-mentioned object, the present inventor has found that in a laminate comprising a partially crosslinked thermoplastic elastomer layer and a polyolefin crosslinked foam layer, the residual odor is reduced and the outer layer is a part. As a result of diligent research on a method for reducing the change in hue of the crosslinked thermoplastic elastomer layer, the outer skin layer was made of crystalline polypropylene and an olefin copolymer rubber, a peroxide crosslinking agent, and a polyvalent acrylate crosslinking assistant. The mixture containing
In an atmosphere of 0.1% or less, while forming by a partially crosslinked thermoplastic elastomer obtained by partially crosslinking by dynamically heat treatment, the crosslinked structure of the polyolefin crosslinked foam is formed by irradiation of ionizing radiation, Furthermore, they have found that the outer skin layer and the polyolefin cross-linked foam layer may be adhered by heat fusion, and have conceived the present invention.

That is, the polyolefin resin laminate of the present invention comprises (I) a partially crosslinked thermoplastic elastomer layer and (II)
A laminate comprising a layer of a polyolefin crosslinked foam, wherein the partially crosslinked thermoplastic elastomer comprises (a) 5 to 80% by weight of crystalline polypropylene and (b) 95 to 20% by weight of an olefin copolymer rubber. And (c) the peroxide-based cross-linking agent 0.015 to 0.10 based on 100 parts by weight of the total of (a) + (b).
045 parts by weight, and (d) polyhydric acrylate-based crosslinking aid 0.2-
2.0 parts by weight, each component is partially crosslinked by dynamically heat-treating in an atmosphere having an oxygen concentration of 0.1% or less, and the (II) polyolefin crosslinked foam is A crosslinked structure is formed by irradiation with ionizing radiation, and the (I) layer and the (II) layer are bonded by heat fusion.

The present invention will be described in detail below. [1] Polyolefin resin laminate The polyolefin resin laminate of the present invention is basically (I)
It comprises a partially crosslinked thermoplastic elastomer composition layer and a (II) polyolefin crosslinked foam layer.

(I) Partially Crosslinked Thermoplastic Elastomer Layer The partially crosslinked thermoplastic elastomer comprises a partially crosslinked thermoplastic elastomer having a specific composition.

The composition components of the partially crosslinked thermoplastic elastomer will be described in detail below. (a) crystalline polypropylene propylene homopolymer or ethylene, 1-butene,
It is a random or block copolymer containing propylene as a main component, which is a copolymer of α-olefins such as 1-pentene, 1-hexene, and 4-methyl-1-pentene. Its melt flow rate (MFR, 230 ° C, 2.16 kg load) is 0.
3 to 300 g / 10 minutes, particularly 10 to 100 g / 10 minutes are preferable. In the case of the copolymer, the propylene content is 60% by weight or more.
Thus, in the present specification, the term "crystalline polypropylene" means not only a propylene homopolymer but also a copolymer.

Crystalline polypropylene has the highest melting point among polyolefins and contributes to the improvement of heat resistance and mechanical strength of the composition.

(B) Olefin-based copolymer rubber ethylene, propylene, 1-butene, 1-hexene, 4
-Methyl-1-pentene and other two or more copolymer rubbers, and two of the above-mentioned monoolefins (preferably ethylene and propylene) and dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, A copolymer rubber with a non-conjugated diene such as methylene norbornene and ethylidene norbornene or a conjugated diene such as butadiene and isoprene is included. Typically, ethylene-propylene copolymer rubber (EPR), ethylene-
Examples thereof include butene copolymer rubber (EBR) and ethylene-propylene-diene copolymer rubber (EPDM).
These olefinic copolymer rubbers may be used alone or in combination of two or more kinds.

The ethylene content of such an olefin copolymer rubber is preferably 35 to 88% by weight, the iodine value (unsaturation) is 30 or less, and the Mooney viscosity ML _{1 + 8.}
(127 ° C) is preferably 5 to 300. The crystallinity of such an olefinic copolymer rubber is usually 40% by weight or less. The olefin-based copolymer rubber is present as a partially crosslinked rubber in the composition and improves its heat resistance rigidity, impact resistance, flexibility and the like.

The compounding ratio of the above-mentioned (a) crystalline polypropylene and (b) olefinic copolymer rubber is 5 to 80% by weight of (a) crystalline polypropylene, with the total amount of both being 100% by weight. %, Preferably 10 to 50% by weight,
(b) The olefin-based copolymer rubber is 95 to 20% by weight, preferably 90 to 50% by weight. When the crystalline polypropylene is less than 5% by weight (when the olefin copolymer rubber exceeds 95% by weight), the mechanical strength decreases, while when the crystalline polypropylene exceeds 80% by weight (the olefin copolymer rubber 20% by weight). If less than), the physical properties of rubber are deteriorated.

(C) Peroxide-based cross -linking agent As the peroxide-based cross-linking agent, there are hydro-based, dialkyl-based, ketal-based, ketone-based, carbonate-based, ester-based, etc., and examples thereof include dicumyl peroxide and di-t. -Butyl peroxide, 2,5-dimethyl-2,5-
Di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,
3-bis (t-butylperoxyisopropyl) benzene, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (t
-Butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-
Dichlorobenzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, t-butyl cumyl peroxide and the like can be mentioned.

The amount of the above-mentioned (c) peroxide crosslinking agent is 0.015 to 0.045 parts by weight, preferably 100 parts by weight of (a) crystalline polypropylene + (b) olefin copolymer rubber. 0.02 to 0.04 parts by weight. If the amount of the peroxide-based crosslinking agent is less than 0.015 parts by weight, the crosslinking of the olefin-based copolymer rubber is insufficient, and if it exceeds 0.045 parts by weight, not only the deterioration of hue, eyes and odor but also the mechanical properties are deteriorated. descend.

(D) Cross-linking auxiliary agent As the cross-linking auxiliary agent, a polyvalent acrylate-based cross-linking auxiliary agent is used for the purpose of preventing toxicity, workability, crosslinking efficiency, and deterioration of hue, odor, and eyes. use.

As the polyhydric acrylate crosslinking aid, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2-
Bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolypropoxy) phenyl] propane and 2- Diacrylate-based crosslinking aids such as hydroxy-1-acryloxy-3-methacryloxypropane, triacrylate-based crosslinking aids such as trimethylolpropane trimethacrylate, tetramethylolmethane trimethacrylate, trimethylolpropane triacrylate and tetramethylolmethane triacrylate. Agents, tetramethylolmethane tetraacrylate, dipentaerythritol hexaacrylate, and other acrylate-based crosslinking aids having a valence of 4 or more. Of these, trimethylolpropane trimethacrylate is particularly preferable.

The compounding amount of the above-mentioned crosslinking aid is 100 (a) crystalline polypropylene + (b) olefin copolymer rubber in total.
0.2-2.0 parts by weight, preferably 0.3-
It is 1.5 parts by weight. When the amount of the crosslinking aid is less than 0.2 parts by weight, the olefin copolymer rubber is insufficiently crosslinked, and 2.
If it exceeds 0 part by weight, poor dispersion of the cross-linking aid will occur and non-uniform cross-linking will occur, resulting in poor mechanical properties.

(E) Other components In addition, if necessary, stabilizers such as softeners, antioxidants, ultraviolet absorbers, and metal deterioration inhibitors, lubricants, antistatic agents, electrical property improvers, flame retardants, and processing agents. Property improver, additives such as pigments, talc, calcium sulfate, barium sulfate, mica,
An inorganic filler such as calcium silicate or the like can be added.

Among the above-mentioned various components, the softening agent weakens the intermolecular force of the elastomer component to facilitate processing, and
A high-boiling petroleum fraction used for the purpose of improving flexibility, elasticity, and moldability. There are paraffin-based, naphthene-based, aromatic-based, etc., and these softening agents are used alone or in combination of two or more. It is preferably used.

The blending amount of the above-mentioned mineral oil-based softening agent is 10 in total of crystalline polypropylene + olefin-based copolymer rubber.
100 parts by weight or less, preferably 5 to 0 parts by weight
It is 50 parts by weight.

Method for Producing Partially Crosslinked Thermoplastic Elastomer The partially crosslinked thermoplastic elastomer used in the present invention is produced by mixing the above-mentioned components and melt-kneading in an atmosphere having an oxygen concentration of 0.1% or less. You can If the oxygen concentration exceeds 0.1%, odor is generated and a large amount of eyes and eyes are generated. As a kneading device, a non-open type Banbury mixer, an extruder (including a twin screw),
A conventionally known one such as a kneader or a continuous mixer can be used. In such a device, a device for ejecting an inert gas such as N ₂ gas is provided below the hopper for supplying the raw material, and the inert gas is ejected from the device into the kneading device to remove the air in the kneading device from the inert gas. And the raw material is supplied while ejecting an inert gas, the melt kneading can be performed in an atmosphere having an oxygen concentration of 0.1% or less.

The kneading is carried out at a temperature at which the half-life of the peroxide-based crosslinking agent used is less than 1 minute (usually a barrel temperature of 130-
280 ° C., preferably 160 to 250 ° C.) for 0.1 to 10 minutes, preferably 0.2 to 3 minutes. In particular, it is preferable to melt-knead the crystalline polypropylene, the olefin-based copolymer rubber, the peroxide-based cross-linking agent, the cross-linking aid and the softening agent using a twin-screw extruder.

Furthermore, in the partially crosslinked thermoplastic elastomer,
It may contain up to 50% by weight of crystalline polyolefin. Examples of the crystalline polyolefin resin include homopolymers of α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, copolymers of ethylene and propylene or other α-olefins, or α of these. -Copolymers of two or more kinds of olefins and the like.

The partially crosslinked thermoplastic elastomer composition comprises
It can be manufactured by mixing the partially crosslinked elastomer described above and the crystalline polyolefin and melt-kneading. As a kneading device, a conventionally known device such as a non-open type Banbury mixer, an extruder (including a twin screw), a kneader, and a continuous mixer can be used.

The partially crosslinked thermoplastic elastomer (or composition thereof) thus obtained has a temperature of 150 to 250 ° C.
A sheet can be formed by extruding from an extruder having a T-die. The thickness of the sheet is
It is preferably 100 to 1000 μm, particularly preferably 200 to 500 μm.

(II) Polyolefin cross-linked foam layer (1) Composition component (a) Resin component The polyolefin used for the polyolefin cross-linked foam is α-, such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene. Examples thereof include homopolymers of olefins, copolymers of ethylene and propylene, or other α-olefins, or copolymers of two or more of these α-olefins. Among these,
Polyethylene and polypropylene are preferred.

Polyethylene is a polymer mainly composed of ethylene, and is about 10 mol% or less with other α-olefins such as propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1. Including a copolymer of The above polyethylene has a melt index of 0.1 to 20 g / 10 min (190 ℃,
2.16 kg load). Examples of such polyethylene include low density polyethylene, linear low density polyethylene, and high density polyethylene. Particularly, linear low density polyethylene is preferable.

Polypropylene is a polymer mainly composed of propylene, and includes ethylene, butene-1, and pentene.
-1, hexene-1, 4-methylpentene-1 and other α-olefins in a proportion of about 10 mol% or less. The above polypropylene has a melt flow rate of 1 to 30 g / 10 min.
(230 ° C., 2.16 kg load) is preferable. Typical examples of such polypropylene resin include homopolypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer and the like.

(B) Foaming agent The foaming agent added to the above resin is a compound that is liquid or solid at room temperature, but decomposes or vaporizes when heated above the melting point of the polyolefin, such as sheeting. Any material may be used as long as it does not substantially interfere with the molding or crosslinking reaction. Especially the decomposition temperature is 180-270 ℃
The range of is preferable. Examples of the foaming agent include azodicarbonamide, azodicarboxylic acid metal salt,
Dinitrosopentamethylenetetramine, hydrazodicarbonamide, p-toluenesulfonyl semicarbazide,
Examples thereof include s-trihydrazinotriazine and the like.

The blending amount of the above foaming agent is polyolefin 10
It is preferably 1 to 30 parts by weight, particularly 2 to 15 parts by weight, relative to 0 parts by weight, and the compounding amount can be appropriately set within the above range according to the desired expansion ratio.

(C) Other Components Various additives, crosslinking aids, pigments, various fillers, flame-retardant substances, anti-participants, etc. may be appropriately added to the composition for polyolefin cross-linked foam. it can.

(2) Manufacturing Method The polyolefin crosslinked foamed product including such various components can be manufactured, for example, by the following method.

First, the various components as described above are mixed,
Melt and knead. As a kneading device, a conventionally known device such as a non-open type Banbury mixer, an extruder (including a twin screw), a kneader, and a continuous mixer can be used.

Next, the kneaded product is extruded into a predetermined shape (usually a sheet). A crosslinked structure is formed in the thus obtained molded body. As a method for forming a cross-linked structure, a chemical cross-linking method by adding an organic peroxide tends to generate a residual odor. Therefore, α rays, β rays (electron rays),
The method of irradiating ionizing radiation such as γ-ray is used. A method using electron beam irradiation is particularly preferable. The dose of radiation is
Generally depends on the degree of formation of crosslinked structure, etc.
It is 50 Mrad, preferably 3 to 15 Mrad.

After the crosslinked structure is formed in this way, foaming is performed. Foaming can be performed by heating to a temperature higher than the melting point of the resin component and the decomposition temperature of the foaming agent. For example, in the case of polyethylene, the temperature should be over 200 ℃, especially 230〜.
250 ℃, 230 ℃ or more for polypropylene, especially 250 ~
It can be performed by heating to 300 ° C. The time required for foaming is usually about 0.5 to 5 minutes.

The polyolefin crosslinked foam thus obtained generally has a gel fraction of 20 to 60% by weight, particularly 25 to 50% by weight (the proportion of insoluble matter after soaking in boiling paraxylene for 24 hours is measured. ), The expansion ratio is 10 to 50 times,
It is particularly preferably 10 to 30 times. The thickness of the foam varies depending on the intended use and the like, but is preferably 1 to 5 mm, particularly preferably 2 to 4 mm.

[2] Method for producing polyolefin resin laminate
Method as described above (I) partially crosslinked thermoplastic elastomer layer,
And (II) the polyolefin resin laminate of the present invention comprising a polyolefin crosslinked foam layer is obtained by heat-sealing a partially crosslinked thermoplastic elastomer sheet and a polyolefin crosslinked foam sheet at a temperature of 200 to 250 ° C. It can be manufactured.

Alternatively, the partially crosslinked thermoplastic elastomer may be extruded and heat-fused with the sheet of the polyolefin crosslinked foamed material in a molten state to produce a so-called extrusion laminating method.

The polyolefin resin laminate of the present invention thus obtained has almost no odor, and the partial crosslinked thermoplastic elastomer layer, which is the outer skin layer, has almost no occurrence of eye blemishes and deterioration of hue.

Although the polyolefin resin laminate of the present invention has been described above, the laminate of the present invention is not limited to a two-layer structure. For example, a partially crosslinked thermoplastic elastomer layer (skin layer) may be formed on both sides of the polyolefin crosslinked foam layer, or, if necessary, a resin substrate layer (polyolefin resin, olefin copolymer rubber). And a mixture of inorganic fillers and the like) may be formed on the polyolefin crosslinked foam layer side or the partially crosslinked thermoplastic elastomer layer side.

[0050]

The polyolefin resin laminate of the present invention comprises a mixture containing crystalline polypropylene, an olefin-based copolymer rubber, a peroxide-based crosslinking agent, and a polyvalent acrylate-based crosslinking aid, with an oxygen concentration of 0.1% or less. In an atmosphere of, an outer skin layer composed of a partially crosslinked thermoplastic elastomer obtained by partially crosslinking by dynamically heat treating,
It is composed of a polyolefin cross-linked foam layer having a cross-linked structure formed by irradiation with ionizing radiation, and since the outer skin layer and the polyolefin cross-linked foam layer are adhered by heat fusion, there is little residual odor and the outer skin layer To the eyes,
Also, almost no deterioration in hue is observed.

Although the reason why such an effect is obtained is not always clear, it is considered to be due to the following three reasons. A small amount of peroxide crosslinking agent is added, a specific crosslinking aid is added, and each of these components is melt-kneaded under a low oxygen concentration to efficiently form a crosslinked structure. By forming an outer skin layer from a composition containing a thermoplastic elastomer and a crystalline polyolefin, in the outer skin layer, peroxide does not remain, and since peroxide decomposition products and polymer decomposition products are not generated, Reduction of residual odor, occurrence of eye blemishes in the outer skin layer, deterioration of hue, etc. are hardly observed. Since the crosslinked structure of the foam is formed by irradiation with ionizing radiation, there is no peroxide-based crosslinking agent in the foam layer which causes odor. The outer skin layer and the polyolefin crosslinked foam layer are adhered to each other without using an adhesive agent that causes odor.

[0052]

The present invention will be described in more detail by the following examples. The following raw material components were used in each of the examples and comparative examples. [1] Propylene-ethylene block copolymer BPP: [density 0.90 g / cm ³ , melt flow rate (MF
R, 230 ° C, 2.16kg load) 20g / 10min, ethylene content 7% by weight] [2] Low density polyethylene LDPE: [density 0.919g / cm ³ , melt index (MI, 190 ° C, 2.16kg load) 0.24 g / 10 minutes] [3] Olefin-based copolymer rubber Ethylene-propylene-ethylidene norbornene copolymer rubber EPDM: [Moonie viscosity ML _{1 + 4} (100 ° C) = 88, iodine value 15.0, propylene content 28% by weight] [4] Softener Naphthene-based and paraffin-based mixed process oil softener: [Flexon 876 manufactured by Exxon Chemical Co., Ltd.] [5] Peroxide-based crosslinking agent (POX) 2,5-dimethyl-2,5-di- (T-Butylperoxy) hexyne-3 [6] Crosslinking aid Trimethylolpropane trimethacrylate (TMP
T)

Production Example 1 Production of partially crosslinked thermoplastic elastomer Propylene-ethylene block copolymer (BPP) 22.7
Parts by weight, 68.2 parts by weight of ethylene-propylene-ethylidene norbornene copolymer rubber (EPDM), 0.02 part by weight of a peroxide-based crosslinking agent (POX), and a crosslinking aid (T
MPT) 0.6 part by weight, and N ₂ is added to the bottom of the hopper.
Using a twin-screw extruder (58 mmφ) with a gas jet,
The N ₂ gas is jetted from the N ₂ gas jet to replace the air in the extruder with the N ₂ gas, and then while the jetting of the N ₂ gas is continued, the barrel temperature is 200 ° C. and the rpm is 0.2 to 3
Melt kneading for a minute. After kneading, 9.1 parts by weight of a softening agent was added, and the mixture was melt-kneaded at a barrel temperature of 200 ° C. for 20 to 30 seconds to obtain pellets of partially crosslinked thermoplastic elastomer (TE-1). The oxygen concentration under the hopper during melt-kneading is 0.05%.
Met.

Production Example 2 Production of partially crosslinked thermoplastic elastomer Propylene-ethylene block copolymer (BPP) 22.7
Parts by weight, 68.2 parts by weight of ethylene-propylene-ethylidene norbornene copolymer rubber (EPDM), 0.12 parts by weight of a peroxide type crosslinking agent (POX), and a crosslinking aid (TMP).
T) 0.12 parts by weight was blended and melt-kneaded using a twin-screw extruder (58 mmφ) at a barrel temperature of 200 ° C. and 250 rpm for 0.2 to 3 minutes. After the kneading, 9.1 parts by weight of the softening agent was added, and the mixture was melt-kneaded at a barrel temperature of 200 ° C. for 20 to 30 seconds to obtain pellets of the partially crosslinked thermoplastic elastomer (TE-2). In addition,
The oxygen concentration under the hopper during melt kneading was about 21%.

Production Example 3 Production of Polypropylene Crosslinked Foam Propylene-ethylene random copolymer (melt flow rate (230 ° C., 2.16 kg load) 5 g / 10 minutes, melting point 147
℃, ethylene content 0.3% by weight) 100 parts by weight, 15 parts by weight of azodicarbonamide and 2 parts by weight of a crosslinking aid (TMPT) were added and mixed in a Henschel mixer, which was then mixed with a twin screw extruder (47 mmφ, L / D = 42) at 160 ° C, 12
The mixture was melt-kneaded at 5 rpm for 0.5 minutes and pelletized.

The pellets were put into an extruder (50 mmφ, L / D =
32) with an extrusion temperature of 160 ° C and a width of 250 mm and a thickness of 1.
It was extruded into a 5 mm sheet. Subsequently, this sheet was irradiated with an electron beam having an accelerating voltage of 750 kV and a dose of 8 Mrad to be crosslinked (a gel fraction measured by the proportion of insoluble matter after being immersed in boiling paraxylene for 24 hours, 53 wt%). Then 250
The mixture was placed in an air oven at ℃ for 1.5 minutes to decompose the foaming agent to obtain a polypropylene crosslinked foamed sheet (f-PP-1).
The thickness of the obtained polypropylene crosslinked foamed sheet is 3 mm
And the expansion ratio was about 25 times.

Production Example 4 Production of polyethylene crosslinked foam Linear low density polyethylene (melt index (190
℃, 2.16kg load) 3g / 10min, melting point 126 ℃, density 0.92g /
cm ³ ) 100 parts by weight, 15 parts by weight of azodicarbonamide and 1 part by weight of a crosslinking aid (TMPT) are added and mixed by a Henschel mixer, and then an extruder having a T-die (50 mm
φ, L / D = 28) and extrude at an extrusion temperature of 140 ° C,
A sheet having a thickness of 1.0 mm was obtained.

Subsequently, this sheet was irradiated with an electron beam having an accelerating voltage of 750 kV and a dose of 6 Mrad to be crosslinked (gel fraction 35% by weight). Then, put it in an air oven at 250 ° C for 1.5 minutes to decompose the foaming agent, and crosslink the polyethylene crosslinked foamed sheet.
(f-PE-1) was obtained. The thickness of the obtained polyethylene crosslinked foamed sheet was 3 mm and the expansion ratio was about 25 times.

Example 1 100 parts by weight of partially crosslinked thermoplastic elastomer (TE-1) was fed to an extruder (50 mmφ, L / D = 32) having a T die, and extruded at a temperature of 230 while melt-kneading at 220 ° C. It was extruded into a sheet having a width of 450 mm and a thickness of 0.3 mm at ℃.

While the extruded product was in a molten state, it was fused with a polypropylene crosslinked foamed sheet (f-PP-1) to obtain a polyolefin resin laminate having a skin layer of a partially crosslinked thermoplastic elastomer and a foamed layer. Obtained.

The odor of the thus-obtained polyolefin resin laminate was evaluated, the presence or absence of the skin layer on the eyes and the discoloration degree of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Example 2 An extruder having 50 parts by weight of partially crosslinked thermoplastic elastomer (TE-1) and 40 parts by weight of low density polyethylene (LDPE) and having a T-die (50 mmφ, L / D = 32). While being melt-kneaded at 220 ° C., it was extruded into a sheet having a width of 450 mm and a thickness of 0.3 mm at an extrusion temperature of 230 ° C.

This extruded product is fused with a polyethylene crosslinked foamed sheet (f-PE-1) in a molten state to form a polyolefin resin laminate having a skin layer of a partially crosslinked thermoplastic elastomer composition and a foam layer. Got the body

The odor of the thus obtained polyolefin resin laminate was evaluated, the presence or absence of the skin layer on the eyes and the degree of discoloration of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Comparative Example 1 100 parts by weight of partially crosslinked thermoplastic elastomer (TE-2) was fed to an extruder having a T die (50 mmφ, L / D = 32), and extruded at a temperature of 230 while melt-kneading at 220 ° C. It was extruded into a sheet having a width of 450 mm and a thickness of 0.3 mm at ℃.

This extruded product was melted and fused with a polypropylene foam sheet (f-PP-1) to obtain a polyolefin resin laminate having a skin layer of a partially crosslinked thermoplastic elastomer and a foam layer. It was

The odor of the polyolefin resin laminate thus obtained was evaluated, the presence or absence of the skin layer on the eyes and the degree of discoloration of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Comparative Example 2 60 parts by weight of partially crosslinked thermoplastic elastomer (TE-2) and 40 parts by weight of low density polyethylene (LDPE) were compounded, and an extruder having a T-die (50 mmφ, L / D = 32). While being melt-kneaded at 220 ° C., it was extruded into a sheet having a width of 450 mm and a thickness of 0.3 mm at an extrusion temperature of 230 ° C.

This extruded product is fused with a polyethylene foam sheet (f-PE-1) in a molten state, and has a skin layer of a partially crosslinked thermoplastic elastomer composition and a polyolefin resin laminate having a foam layer. Got

The odor of the thus obtained polyolefin resin laminate was evaluated, the presence or absence of the skin layer on the eye and the discoloration degree of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Comparative Example 3 In Example 2, as the polyolefin crosslinked foam, a polyethylene crosslinked foam by chemical crosslinking (Sekisui Chemical Co., Ltd.)
Manufactured by Softlon BN # 3010: f-PE-2) was used to produce a polyolefin resin laminate in the same manner.

The odor of the obtained polyolefin resin laminate was evaluated, the presence or absence of the skin layer on the eyes and the degree of discoloration of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Comparative Example 4 In Comparative Example 2, a polyethylene cross-linked foam by chemical cross-linking as a foam (manufactured by Sekisui Chemical Co., Ltd., Softlon B).
N # 3010: f-PE-2) was used in the same manner as above to produce a polyolefin resin laminate.

The odor of the obtained polyolefin resin laminate was evaluated, the presence or absence of the skin layer on the eyes and the skin, and the discoloration degree of the skin layer were measured. The results are shown in Table 1 together with the composition of the skin layer and the type of foam.

Table 1 Epidermis Example 1 Example 2 Comparative Example 1 Comparative example 2 Comparative Example 3 Comparative Example 4 Thermoplastic Elastomer Type TE-1 TE-1 TE-2 TE-2 TE-1 TE-2 Amount (parts by weight) 100 60 100 60 60 60 60 LDPE Amount (parts by weight) -40-40 40 40 40Foam layer Type f-PP-1 f-PE-1 f-PP-1 f-PE-1 f-PE-2 f-PE-2Characteristic Odor⁽¹⁾ ○ ○ × × × ×⁽²⁾ ○ ○ × × ○ × Hue⁽³⁾ 6.0 5.4 31.2 23.3 5.4 23.3

(1) Odor: A skin material made of a mixture of BPP and EPDM to which a peroxide type crosslinking agent and a crosslinking aid were not added was used as a propylene-ethylene random copolymer (melt flow rate (230 ° C., 2.16 kg Load) 5g / 10
Min., Melting point 147 ° C., ethylene content 0.3% by weight) laminated body (standard sample) fused to a non-foamed sheet, and 1 kg of each example and comparative example laminated body (comparative sample) in a 125 liter container. After sealing each and storing at 60 ° C for 48 hours, open the container and remove the odor of 2 standard samples and 1 comparative sample.
Evaluation was performed according to the following criteria by a sensory test method by a panel test of point comparison. ◯: 12 or more out of 15 panelists judged that there was no difference in odor between the comparative sample and the standard sample, and the odor was slight or odorless. ×: 12 or more out of 15 panelists judged that the comparative sample had a stronger odor than the standard sample. Δ: Less than 12 people judged that there was no difference in odor between the standard sample and the comparative sample, and less than 12 people judged that the comparative sample had a stronger odor than the standard sample. (2) Eyes and eyes: The eyes and eyes are that the composition is formed into a sheet shape, or the sheets are laminated by fusing or the like, and then the volatile components in the composition adhere to the sheet surface to roughen the sheet surface, The presence or absence of the outer skin layer of the polyolefin resin laminate was evaluated according to the following criteria. ◯: Eyes and eye rash have not occurred for more than 72 hours. Δ: Eyes and eyes were observed in 12 to 72 hours. X: Eye blemishes occurred within 6 hours. (3) Hue: Yellowness of the skin layer measured according to JIS K7105
(YI) is displayed.

As is clear from Table 1, the polypropylene resin laminate of the present invention had little residual odor, and almost no generation of eye blemishes and decrease in hue (yellowing) was observed in the skin layer. On the other hand, all the compositions of Comparative Examples had a remarkable odor. In particular, the laminates (Comparative Examples 1, 2 and 4) using the one having a large addition amount of the organic peroxide (TE-2) as the partially cross-linked thermoplastic elastomer component generate eye blemishes and decrease in hue (yellowing). ) Was remarkable.

[0078]

As described in detail above, the polyolefin resin laminate of the present invention contains crystalline polypropylene, an olefin copolymer rubber, a peroxide crosslinking agent, and a polyvalent acrylate crosslinking assistant. Oxygen concentration in the mixture
From an outer skin layer made of a partially crosslinked thermoplastic elastomer obtained by partially crosslinking by dynamically heat treating in an atmosphere of 0.1% or less, and a polyolefin crosslinked foam layer having a crosslinked structure formed by ionizing radiation. And both layers are bonded by heat fusion. Such a laminate is
There is little residual odor, and there is almost no occurrence of eye blemishes and deterioration of hue in the outer skin layer.

Such a polyolefin resin laminate of the present invention is particularly suitable for building materials, interior materials for automobiles, housings for household electric appliances and the like.

Claims (1)

[Claims] 1. A laminate comprising (I) a partially crosslinked thermoplastic elastomer layer and (II) a layer of polyolefin crosslinked foam, wherein the partially crosslinked thermoplastic elastomer comprises:
(a) 5 to 80% by weight of crystalline polypropylene, (b) 95 to 20% by weight of olefinic copolymer rubber, and (c) per 100 parts by weight of (a) + (b) in total. Oxide crosslinking agent
0.015 to 0.045 parts by weight and (d) 0.2 to 2.0 parts by weight of a polyvalent acrylate cross-linking aid, and each component is dynamically heat treated in an atmosphere with an oxygen concentration of 0.1% or less. The (II) polyolefin crosslinked foam has a crosslinked structure formed by irradiation with ionizing radiation, and the (I) layer and the (II) layer are heat-melted. A polyolefin resin laminate characterized by being adhered by wearing.