JP7316032B2 - Thermoplastic resin sheets, laminates and moldings. - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin sheet, and a laminate and molded article using the same.

BACKGROUND ART Conventionally, thermoplastic resin sheets have been widely used in various fields because they can be easily manufactured into products having desired shapes by various molding methods such as vacuum molding. In particular, in automobile applications, it is used as a surface material for interior materials such as ceilings, doors, instrument panels, etc., in order to enhance design, feel, and luxury. For example, a crosslinked olefin resin foam is used as an interior material for automobiles, and the crosslinked olefin resin foam is often used as a laminate by laminating a thermoplastic resin sheet as a skin material.
In the case of crosslinked polyolefin resin foams, odors resulting from decomposition products of the polyolefin resin are released into the vehicle through the skin material made of the thermoplastic resin sheet, and the user often feels uncomfortable.
Further, the thermoplastic resin sheet may be heated during its manufacture, molding, or the like, which may generate decomposition products of the resin, and the thermoplastic resin sheet itself may also cause odor.
Techniques for reducing odors include, for example, a method using a deodorant such as activated carbon (Patent Document 1) and a method using carbon black or the like as an odor suppressant (Patent Document 2).

JP-A-11-60774 JP-A-11-263863

However, for example, when an automobile interior material provided with a thermoplastic resin sheet is used, there is a problem that the odor cannot be sufficiently reduced even by using the conventional technology, especially in hot summer months.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermoplastic resin sheet having good moldability and capable of reducing odor generation, and a laminate and a molded article using the thermoplastic resin sheet.

As a result of intensive studies to achieve the above object, the present inventors have found that by adding a certain amount of a deodorant containing porous particles and a predetermined hydrazide to a thermoplastic resin, molding can be performed. The inventors have found that it is possible to obtain a thermoplastic resin sheet that has good properties and can reduce the generation of odor, and have completed the present invention.
That is, the present invention relates to the following [1] to [10].
[1] Contains 0.2 to 7 parts by mass of a deodorant with respect to 100 parts by mass of a thermoplastic resin,
The deodorant is a thermoplastic resin sheet containing porous particles and hydrazides represented by the following general formula (1).

(Wherein, R represents a hydrogen atom, a group —NH—NH ₂ , or a residue obtained by removing a carboxyl group from a mono-, di-, tri- or tetracarboxylic acid, and n represents an integer of 1 to 4.)
[2] The thermoplastic resin sheet according to [1] above, wherein the hydrazide is at least one selected from the group consisting of carbohydrazide, succinic dihydrazide, adipic dihydrazide, and isophthalic dihydrazide.
[3] The thermoplastic resin sheet according to [1] or [2] above, wherein the porous particles are silica-based porous particles.
[4] The thermoplastic resin sheet according to any one of [1] to [3] above, wherein the thermoplastic resin contains an olefinic thermoplastic elastomer.
[5] The thermoplastic resin sheet according to any one of [1] to [4] above, which is a skin material.
[6] A laminate comprising a crosslinked polyolefin resin foam and the thermoplastic resin sheet according to any one of [1] to [5] laminated on the crosslinked polyolefin resin foam.
[7] The laminate according to [6] above, wherein the crosslinked polyolefin resin foam is obtained by crosslinking and foaming a foamable composition containing a polyolefin resin.
[8] The laminate according to [7] above, wherein the polyolefin resin contains a polypropylene-based resin.
[9] A molded article obtained by molding the laminate according to any one of [6] to [8] above.
[10] The molded article according to [9] above, which is an automotive interior material.

According to the present invention, it is possible to provide a thermoplastic resin sheet having good moldability and capable of reducing odor generation, and a laminate and molded article using the thermoplastic resin sheet.

[Thermoplastic resin sheet]
The thermoplastic resin sheet of the present invention contains 0.2 to 7 parts by mass of a deodorant with respect to 100 parts by mass of the thermoplastic resin, and the deodorant comprises porous particles and the following general formula (1) Including hydrazides shown in.

(Wherein, R represents a hydrogen atom, a group —NH—NH ₂ , or a residue obtained by removing a carboxyl group from a mono-, di-, tri- or tetracarboxylic acid, and n represents an integer of 1 to 4.)

(Deodorants)
The thermoplastic resin sheet of the present invention contains 0.2 to 7 parts by mass of deodorant with respect to 100 parts by mass of thermoplastic resin. The deodorant can reduce odor generation from the thermoplastic resin sheet. Furthermore, in the laminate of the thermoplastic resin and the crosslinked polyolefin resin foam, the odor generated from the crosslinked polyolefin resin foam can also be reduced.
If the content of the deodorant is less than 0.2 parts by mass with respect to 100 parts by mass of the thermoplastic resin, the degree of reduction in the generation of odor is small. On the other hand, when the content of the deodorant exceeds 7 parts by mass with respect to 100 parts by mass of the thermoplastic resin, the surface of the thermoplastic resin sheet is whitened during molding, resulting in poor moldability. On the other hand, if the content of the deodorant is too large, the degree of reduction in the generation of odor becomes small.
From such a viewpoint, the content of the deodorant is preferably 0.3 to 6.0 parts by mass, more preferably 0.4 to 5.5 parts by mass, relative to 100 parts by mass of the thermoplastic resin. and more preferably 0.5 to 5.0 parts by mass.

A deodorant is usually powdery. The average particle size of the deodorant is preferably 0.1 to 100 μm, more preferably 0.5 to 20 μm, and still more preferably 2 to 2 μm, as a volume-based median diameter measured with a laser diffraction particle size distribution meter. 10 μm.

<Porous particles>
The porous particles contained in the deodorant are not particularly limited as long as they are porous. From the viewpoint of dispersing the hydrazides represented by the general formula (1) on the surfaces of the porous particles, the porous particles are preferably porous particles capable of supporting the hydrazides. From this point of view, the porous particles are preferably inorganic porous particles, more preferably silica-based porous particles. Silica-based porous particles include, for example, silica such as silica gel, zeolite, montrollilonite, hydrotalcite, and the like. Porous particles other than silica-based porous particles include, for example, aluminum oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, strontium hydroxide, barium hydroxide, water Zirconium oxide, zirconium phosphate, titanium phosphate, aluminum phosphate and the like can be mentioned. These may be used individually by 1 type, and may be used in mixture of 2 or more types. Among these, silica such as silica gel and zeolite are preferred, and silica is more preferred. Odor generation can be effectively suppressed by including porous particles in the deodorant.

<Hydrazides>
The hydrazides represented by the general formula (1) include, for example, a monohydrazide compound having one hydrazide group in the molecule, a dihydrazide compound having two hydrazide groups in the molecule, and three hydrazide groups in the molecule. and a tetrahydrazide compound having four hydrazide groups in the molecule. When R is a residue obtained by removing a carboxyl group from a mono-, di-, tri- or tetracarboxylic acid, the carbon number is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15.

Monohydrazide compounds include, for example, monohydrazide compounds represented by the following general formula (2).

(wherein R ¹ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group which may have a substituent).

In the above general formula (2), the alkyl group represented by R ¹ includes, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-heptyl group. , n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group and the like. The aryl group represented by R ¹ includes, for example, a phenyl group, a biphenyl group, a naphthyl group, etc. Among these, a phenyl group is preferred. Examples of substituents of the aryl group include, for example, hydroxyl group, halogen atoms such as fluorine, chlorine and bromine, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, iso A linear or branched alkyl group having 1 to 4 carbon atoms such as -butyl group.

Examples of the monohydrazide compound represented by the general formula (2) include lauric hydrazide, salicylic hydrazide, formhydrazide, acetohydrazide, propionic hydrazide, p-hydroxybenzoic hydrazide, naphthoic hydrazide, and 3-hydroxy-2-naphthoic acid. and acid hydrazides.

Dihydrazide compounds include, for example, dihydrazide compounds represented by the following general formula (3).

(In the formula, R ² represents a group —CO— or a group —CO—R ³ —CO—. ^{R 3} may have a C 1-12 alkylene group or a substituent represents an arylene group.)

In the above general formula (3), the alkylene group represented by ^R3 includes, for example, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene straight-chain alkylene groups having 1 to 12 carbon atoms such as a decamethylene group, an undecamethylene group, and the like. Preferred alkylene groups are linear alkylene groups having 2 to 6 carbon atoms, and more preferred are ethylene, tetramethylene and hexamethylene groups. Substituents for the alkylene group include, for example, a hydroxyl group and the like. The arylene group represented by ^R3 includes, for example, a phenylene group, a biphenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, etc. Among these, a phenylene group, a naphthylene group, etc. are preferable. Examples of substituents for the arylene group include those similar to the substituents for the aryl group described above.

Examples of the dihydrazide compound of the general formula (3) include carbohydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecane-diacid dihydrazide, and maleic acid dihydrazide. , fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, dimer acid dihydrazide, dibasic acid dihydrazide such as 2,6-naphthoic acid dihydrazide, and the like.

Trihydrazide compounds include, for example, citric acid trihydrazide, trinitroacetic acid trihydrazide, nitriloacetic acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide and the like.

Tetrahydrazide compounds include, for example, ethylenediaminetetraacetic acid tetrahydrazide and naphthoic acid tetrahydrazide.

These hydrazides may be used singly or in combination of two or more. Among these, dihydrazide compounds are more preferable, and among the dihydrazide compounds, at least one selected from the group consisting of carbohydrazide, succinic dihydrazide, adipic dihydrazide, and isophthalic dihydrazide is more preferable. Among them, adipic acid dihydrazide is particularly preferred.

From the viewpoint of more effectively suppressing the generation of odor, the hydrazides are preferably supported on the porous particles. For example, hydrazides can be supported on porous particles by an impregnation method.

(Thermoplastic resin)
The thermoplastic resin sheet of the present invention contains a thermoplastic resin. Thermoplastic resins include thermoplastic elastomers such as olefin-based thermoplastic elastomers (TPO), styrene-based thermoplastic elastomers, ester-based thermoplastic elastomers, amide-based thermoplastic elastomers, polypropylene-based resins, polyethylene-based resins, poly(1- ) polyolefin resins such as butene resins, acrylonitrile-butadiene-styrene (ABS) resins, polycarbonate resins, polyphenylene ether resins, (meth)acrylic resins, polyamide resins, polyvinyl chloride resins (PVC), and the like.

Among these, the thermoplastic resin preferably contains an olefinic thermoplastic elastomer (TPO). By containing the olefin-based thermoplastic elastomer (TPO), the thermoplastic resin sheet tends to have good flexibility and moldability, and the thermoplastic resin sheet and the crosslinked polyolefin resin foam described later can be heat-sealed. make it easier to
As the olefinic thermoplastic elastomer (TPO), any one of blend type, dynamic cross-linking type and polymerization type can be used. Specific examples of olefinic thermoplastic elastomers include those containing polypropylene as a hard segment and a copolymer containing ethylene, propylene and, if necessary, a small amount of diene component as a soft segment. Examples of the copolymer include ethylene-propylene copolymer (EPR) and ethylene-propylene-diene copolymer (EPDM).
Other specific examples of olefinic thermoplastic elastomers (TPO) include a blend of polyethylene and EPR, a blend of polyethylene and EPR partially crosslinked using an organic peroxide, and a blend of polyethylene and EPR. and butyl-grafted polyethylene, etc., which are graft-modified with unsaturated hydroxy monomers, unsaturated carboxylic acid derivatives, and the like.
The content of the olefinic thermoplastic elastomer (TPO) is preferably 30 to 100% by mass, preferably 50 to 95% by mass, and 70 to 90% by mass, based on the total amount of the thermoplastic resin. is preferred.

Moreover, when using an olefin-based thermoplastic elastomer (TPO) as the above-described thermoplastic resin, it is preferable to use it together with a polyolefin-based resin. When these are used in combination, the moldability into a sheet is improved, making it easier to produce a thermoplastic resin sheet. In addition, a thermoplastic resin sheet using these materials in combination is easily heat-sealed with a crosslinked polyolefin resin foam, which will be described later, and easily forms a laminate.
The polyolefin-based resin used in combination with the olefin-based thermoplastic elastomer (TPO) preferably contains at least one of a polypropylene-based resin and a polyethylene-based resin, and more preferably includes both a polypropylene-based resin and a polyethylene-based resin. More preferably, it consists of a polypropylene resin and a polyethylene resin.

Examples of polypropylene-based resins include homopolypropylene, ethylene-propylene random copolymers containing propylene as a main component, and ethylene-propylene block copolymers containing propylene as a main component. They may be used or two or more may be used in combination. Among them, it is preferable to use an ethylene-propylene random copolymer containing propylene as a main component.

Examples of polyethylene resins include, but are not limited to, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and ethylene-α-olefin copolymers containing ethylene as a main component. These may be used singly or in combination of two or more. Among the above polyethylene-based resins, linear low-density polyethylene is preferred.

When an olefinic thermoplastic elastomer (TPO) and a polyolefinic resin are used together, the content of the olefinic thermoplastic elastomer (TPO) is preferably 50 to 95% by mass based on the total amount of the thermoplastic resin, and 70% by mass. It is preferably ~90% by mass. The content of the polyolefin resin is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, based on the total amount of the thermoplastic resin.
Furthermore, when the polyolefin-based resin contains a polypropylene-based resin and a polyethylene-based resin, the content of the polypropylene-based resin is preferably 2.5 to 25% by mass, based on the total amount of the thermoplastic resin, and 5 to 15% by mass. % is more preferred. The content of the polyethylene-based resin is preferably 2.5 to 25% by mass, more preferably 5 to 15% by mass, based on the total amount of the thermoplastic resin.

The thermoplastic resin sheet can be produced by processing the composition containing the thermoplastic resin and deodorant described above into a sheet by a known method, for example, using a kneader such as a Banbury mixer or a pressure kneader. It can be produced by kneading the mixture with an extruder, calendering, conveyor belt casting, or the like, and then continuously extruding the mixture.

As described above, the thermoplastic resin sheet of the present invention can reduce odor and has good moldability, so it can be used as a skin material, and more preferably as a skin material for vehicle interior materials. can be used as The skin material can be attached to various members such as foams to form a laminate, and is arranged on the outermost surface of the laminate. Odors generated from the entire laminate are effectively reduced.
For example, a laminate obtained by laminating the thermoplastic resin sheet of the present invention on a crosslinked polyolefin resin foam to be described later reduces odors generated from the crosslinked polyolefin resin foam by the thermoplastic resin sheet that is the skin material. Since the odor emitted from the surface to the outside is suppressed, the laminate has little odor.

[Laminate]
The laminate of the present invention comprises a crosslinked polyolefin resin foam and the thermoplastic resin sheet laminated on the crosslinked polyolefin resin foam.

(Crosslinked polyolefin resin foam)
The crosslinked polyolefin resin foam in the laminate of the present invention is obtained by crosslinking and foaming a foamable composition containing a polyolefin resin. Each component contained in the foamable composition will be described in detail below.

(polyolefin resin)
Polyolefin resins contained in the foamable composition include, for example, polyethylene-based resins, polypropylene-based resins, ethylene-vinyl acetate resins, olefin-based thermoplastic elastomers, and the like. The polyolefin resin preferably contains a polypropylene resin, and more preferably contains both a polypropylene resin and a polyethylene resin, from the viewpoint of improving the heat resistance and moldability of the resulting crosslinked polyolefin resin foam. preferable.

Examples of polypropylene-based resins include homopolypropylene, ethylene-propylene random copolymers containing propylene as a main component, and ethylene-propylene block copolymers containing propylene as a main component. They may be used or two or more may be used in combination. Among them, it is preferable to use an ethylene-propylene random copolymer containing propylene as a main component.
The melt flow rate (hereinafter referred to as "MFR") of the polypropylene-based resin is preferably 70 g/10 minutes or less, more preferably 50 g/10 minutes or less, and still more preferably 25 g/10 minutes or less. Also, the lower limit of MFR is usually 0.1 g/10 minutes.
The above MFR is a value measured under conditions of a temperature of 230° C. and a load of 21.2 N in accordance with JIS K 7210.

Examples of polyethylene resins include, but are not limited to, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and ethylene-α-olefin copolymers containing ethylene as a main component. These may be used singly or in combination of two or more. Among the above polyethylene-based resins, linear low-density polyethylene is preferred. The density of the linear low-density polyethylene is preferably 0.900-0.925 g/cm ³ , more preferably 0.902-0.922 g/cm ³ .
The MFR of the polyethylene resin is preferably 0.5 to 70 g/10 minutes, more preferably 1.5 to 50 g/10 minutes.
The above MFR is a value measured under conditions of a temperature of 190° C. and a load of 21.2 N in accordance with JIS K 7210.

When the polyolefin resin contains a polypropylene-based resin, it preferably contains 50% by mass or more, more preferably 55% by mass or more of the polypropylene-based resin in the polyolefin resin from the viewpoint of improving heat resistance.
When the polyolefin resin contains a polyethylene-based resin and a polypropylene-based resin, the amount of the polypropylene-based resin is preferably larger, and the polypropylene-based resin is preferable based on the total amount of the polyethylene-based resin and the polypropylene-based resin. It is 50% by mass or more, more preferably 55% by mass or more. With such a compounding amount, the heat resistance and flexibility of the crosslinked polyolefin resin foam are improved.
In addition, the foamable composition may contain resins other than polyolefin resin, but the content of polyolefin resin is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably, based on the total resin. is 90% by mass or more.
In addition, when the polyolefin resin contains a polypropylene-based resin, it is necessary to foam the foamable composition at a high temperature. For this reason, when the polyolefin resin contains a polypropylene-based resin, it is believed that an aldehyde compound having 6 to 11 carbon atoms, which is presumed to be an odor-causing substance, is likely to be generated. However, in the laminate of the present invention, generation of odor is reduced by laminating a thermoplastic resin sheet containing a specific deodorant on the crosslinked polyolefin resin foam.

<Antioxidant>
The foamable composition used for the crosslinked polyolefin resin foam of the present invention preferably contains an antioxidant. By containing an antioxidant, it is possible to suppress oxidative deterioration of the polyolefin resin and to reduce the generation of odor from the crosslinked polyolefin resin foam. The content of the antioxidant is preferably 0.5 to 5.0 parts by mass, more preferably 1.0 to 4.0 parts by mass, based on 100 parts by mass of the polyolefin resin.
By adding 0.5 parts by mass or more of the antioxidant to 100 parts by mass of the polyolefin resin, the oxidative deterioration of the polyolefin resin is further suppressed, and the odor generation of the crosslinked polyolefin resin foam can be further reduced. . Moreover, by setting the antioxidant to 5.0 parts by mass or less with respect to 100 parts by mass of the polyolefin resin, it is possible to suppress excessive antioxidant from becoming an odorant.

Although the type of antioxidant is not particularly limited, examples thereof include phenol antioxidants, sulfur antioxidants, phosphorus antioxidants, and amine antioxidants. Among these, phenol-based antioxidants are preferred from the viewpoint of reducing the generation of odors from the crosslinked polyolefin resin foam.
Phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2-tert- Butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate ] methane and the like. Among these, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane is preferred.
One type of antioxidant may be used alone, or two or more types may be used in combination.

<Crosslinking aid>
The foamable composition preferably contains a cross-linking aid. The content of the cross-linking aid in the foamable composition is preferably 2.0 to 5.0 parts by mass, more preferably 2.5 to 4.7 parts by mass with respect to 100 parts by mass of the polyolefin resin. More preferably, the amount of the cross-linking aid is 2.0 parts by mass or more per 100 parts by mass of the polyolefin resin, so that the odor of the foam can be reduced. This is presumably because the polyolefin resin is crosslinked to some extent, thereby suppressing deterioration due to heat and the like, and as a result, suppressing the production of odor-causing substances. By setting the cross-linking aid to 5.0 parts by mass or less with respect to 100 parts by mass of the polyolefin resin, it becomes easy to prevent defective foaming.
In addition, by setting the amount of the cross-linking aid in the foamable composition to such a range and setting the amount of the antioxidant to the above range, the generation of odor-causing substances in the foam can be suppressed, and the effect is improved. Odor generation from the foam can be effectively reduced.

Examples of cross-linking aids include trifunctional (meth)acrylate compounds, polyfunctional (meth)acrylate compounds such as bifunctional (meth)acrylate compounds, compounds having three functional groups in one molecule, and the like. mentioned. Other cross-linking aids include compounds having two functional groups in one molecule such as divinylbenzene, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, ethylvinylbenzene, lauryl methacrylate, stearyl methacrylate, and the like. be done.
Examples of trifunctional (meth)acrylate compounds include trimethylolpropane trimethacrylate and trimethylolpropane triacrylate.
Bifunctional (meth)acrylate compounds include 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, and neopentyl glycol dimethacrylate.
Compounds having three functional groups in one molecule include triallyl trimellitate, triallyl 1,2,4-benzenetricarboxylic acid, and triallyl isocyanurate.
A cross-linking coagent can be used individually or in combination of 2 or more.
Among these, polyfunctional (meth)acrylate-based compounds are preferred, bifunctional (meth)acrylate-based compounds are more preferred, and 1,9-nonanediol dimethacrylate is even more preferred, from the viewpoint of reducing the generation of odor from the foam. .

<Blowing agent>
Methods for foaming foamable compositions include chemical foaming methods and physical foaming methods. The chemical foaming method is a method of forming bubbles by gas generated by thermal decomposition of a compound added to the foaming composition, and the physical foaming method impregnates the foaming composition with a low boiling point liquid (foaming agent). After that, the foaming agent is volatilized to form cells. The foaming method is not particularly limited, but a chemical foaming method is preferred.
As the foaming agent, a thermally decomposable foaming agent is preferably used. For example, an organic or inorganic chemical foaming agent having a decomposition temperature of about 140 to 270° C. can be used.
Organic foaming agents include azodicarbonamide, azodicarboxylic acid metal salts (barium azodicarboxylate, etc.), azo compounds such as azobisisobutyronitrile, nitroso compounds such as N,N'-dinitrosopentamethylenetetramine, Hydrazodicarbonamide, 4,4'-oxybis(benzenesulfonylhydrazide), hydrazine derivatives such as toluenesulfonylhydrazide, semicarbazide compounds such as toluenesulfonylsemicarbazide, and the like.

Examples of inorganic foaming agents include ammonium acid, sodium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodium borohydride, and anhydrous monosoda citric acid.
Among these, azo compounds and nitroso compounds are preferred from the viewpoint of obtaining fine air bubbles and from the viewpoints of economy and safety, and azodicarbonamide, azobisisobutyronitrile, and N,N'-dinitrosopentamethylene. Tetramine is more preferred, and azodicarbonamide is particularly preferred.
A foaming agent can be used individually or in combination of 2 or more types.
The amount of the foaming agent added to the foamable composition is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the polyolefin resin, from the viewpoint of easily adjusting the apparent density of the foam to the above range. , 3 to 12 parts by mass is more preferable.

<Other additives>
Additives commonly used for foams such as heat stabilizers, colorants, flame retardants, antistatic agents, fillers, rust inhibitors, and decomposition temperature regulators are added to the foamable composition as necessary. may be blended.

<Independent porosity>
The closed porosity of the crosslinked polyolefin resin foam of the present invention is preferably 70% or more. When the closed porosity is 70% or more, the odor generation of the foam can be further reduced.
The closed porosity of the foam is more preferably 80% or more, still more preferably 90% or more, from the viewpoint of further reducing odor generation.
The closed cell rate can be measured by the method described in Examples below.

<Apparent density>
The apparent density of the crosslinked polyolefin resin foam of the present invention is not particularly limited, but is preferably 20 to 100 kg/m ³ , more preferably 25 to 80 kg/m ³ , still more preferably 40 to 70 kg/m ³ . is. When the apparent density is 20 kg/m ³ or more, the mechanical strength of the foam can be improved, and when the apparent density is 100 kg/m ³ or less, the flexibility of the foam can be easily secured. The apparent density of the crosslinked polyolefin resin foam is measured by the method described in Examples below.
The apparent density can be measured by the method described in Examples below.

<Thickness>
The thickness of the crosslinked polyolefin resin foam is not particularly limited, but is preferably 0.05 to 15 mm, more preferably 1 to 10 mm. The thickness of the crosslinked polyolefin resin foam is measured by the method described in Examples below.
The thickness can be measured by the method described in Examples below.

<Degree of cross-linking>
The degree of cross-linking of the cross-linked polyolefin resin foam of the present invention is preferably 15 to 65% by mass. When the degree of cross-linking is 15 to 65% by mass, the mechanical strength, flexibility and moldability of the foam can be improved in a well-balanced manner. From the viewpoint that the mechanical strength, flexibility and moldability of the foam can be improved in a well-balanced manner, the degree of cross-linking of the cross-linked polyolefin resin foam of the present invention is more preferably 20 to 55% by mass, and even more preferably. is 30 to 50% by mass.
The degree of cross-linking can be measured by the method described in Examples below.

[Method for producing crosslinked polyolefin resin foam]
The production method for producing the crosslinked polyolefin resin foam of the present invention may include, for example, steps 1 to 3 below.
(Step 1) Step of processing a foamable composition containing a polyolefin resin into a sheet to produce a foamable sheet (Step 2) Irradiating the foamable sheet with ionizing radiation to produce a crosslinked foamable sheet Step (Step 3) A step of foaming the crosslinked foamable sheet to produce a crosslinked polyolefin resin foam

(Step 1)
Step 1 is a step of processing a foamable composition containing a polyolefin resin into a sheet to produce a foamable sheet. A foamable sheet is produced by kneading a foamable composition containing a polyolefin resin using a kneader such as a Banbury mixer or a pressure kneader, and then continuously extruding the mixture using an extruder, a calendar, conveyor belt casting, or the like. be able to.

(Step 2)
Step 2 is a step of irradiating the foamable sheet with ionizing radiation to produce a crosslinked foamable sheet.
The irradiation dose when irradiating the ionizing radiation is preferably 1.2 to 2.5 Mrad, more preferably 1.3 to 2.3 Mrad, from the viewpoint of reducing the odor generation of the crosslinked polyolefin resin foam. and more preferably 1.4 to 2.1 Mrad.
From the viewpoint of further reducing the generation of odor from the crosslinked polyolefin resin foam, it is preferable to adjust the amount of the cross-linking aid in the foamable composition within the above range and to set the ionizing radiation irradiation conditions within the above range.
Ionizing radiation may be applied to one side or both sides of the foam sheet. It is preferable to do this on both sides.
Examples of ionizing radiation include electron beams, α-rays, β-rays, γ-rays, and X-rays. Among these, an electron beam is preferable from the viewpoint of productivity and uniform irradiation.

(Step 3)
Step 3 is a step of foaming the crosslinked foamable sheet to produce a sheet-like crosslinked polyolefin resin foam. Examples of the method for foaming the crosslinkable sheet include a batch method such as an oven, and a continuous foaming method in which the crosslinkable and foamable sheet is continuously passed through a heating furnace.
The temperature at which the crosslinkable foamable sheet is foamed is preferably 160 to 280°C. By setting the temperature to 160°C or higher, foaming can be facilitated, and by setting the temperature to 280°C or lower, generation of odor from the crosslinked polyolefin resin foam can be reduced. The temperature at which the crosslinkable foamable sheet is foamed is more preferably 180 to 270°C, more preferably 200 to 260°C.
The method for adjusting the temperature to the above temperature is not particularly limited, but hot air may be used, or infrared rays may be used.
Moreover, the crosslinkable foamable sheet may be stretched in one or both of the MD direction and the CD direction after foaming or while being foamed.

[Laminate production method]
The laminate of the present invention can be produced by laminating and bonding a thermoplastic resin sheet and a crosslinked polyolefin resin foam. Examples of the method for laminating the two include an extrusion lamination method, an adhesive lamination method in which the two are laminated after applying an adhesive, a heat lamination method (thermal fusion bonding method), a hot melt method, a high frequency welder method, and the like. Both should just be adhere|attached also by the method.

Moreover, the laminated body of this invention can be shape|molded and can be set as a molded object. Examples of the molding method for the molded body include stamping molding, vacuum molding, compression molding, injection molding and the like. Among these, the stamping molding method and the vacuum molding method are preferred. As the vacuum forming method, both the male-pulling vacuum forming method and the female-pulling vacuum forming method can be employed, but the male-pulling vacuum forming method is more preferable.
The molded article of the present invention may have a substrate on the side of the crosslinked polyolefin resin foam. The base material serves as the skeleton of the molded article, and is usually made of a thermoplastic resin. As the thermoplastic resin for the substrate, the above-mentioned polyolefin resin, copolymer of ethylene and α-olefin, vinyl acetate, acrylic acid ester, etc., ABS resin, polystyrene resin, and the like can be applied.
The molded article of the present invention can be used as a heat insulating material, a cushioning material, etc., and is less likely to emit odors even in the hot summer months. It can be suitably used as an automobile interior material.

The present invention will be described in more detail with reference to examples, but the present invention is not limited by these examples.

The details of the raw materials used in each example and comparative example are as follows.
(Raw material for thermoplastic resin sheet)
・TPO: Thermoplastic olefin elastomer, manufactured by Mitsui Chemicals, Inc., trade name “8030NS”
LLDPE (1): Linear low-density polyethylene, manufactured by Prime Polymer Co., Ltd., trade name "2022L", density 0.919 g/cm ³ , MFR 2.0 g/10 min
- Polypropylene resin (1): Ethylene-propylene random copolymer, manufactured by Prime Polymer Co., Ltd., trade name "F227D", density 0.910 g/cm ³ , MFR 7.0 g/10 min
・Deodorant (1): A deodorant containing zeolite (content: about 80% by mass) and adipic acid dihydrazide (content: about 20% by mass), manufactured by Sinanen Zeomic Co., Ltd., trade name "Dashlight"7MH"
- Deodorant (2): Adipic acid dihydrazide (deodorant containing no porous particles), manufactured by Otsuka Chemical Co., Ltd., trade name "Chemcatch H-6000HS", melting point: 180 ° C.

(Raw material for crosslinked polyolefin resin foam)
- Polypropylene resin (2): Ethylene-propylene random copolymer, manufactured by Sumitomo Chemical Co., Ltd., trade name "AD571", density 0.90 g/cm ³ , MFR 0.5 g/10 minutes (230°C)
LLDPE (2): Linear low-density polyethylene: manufactured by Prime Polymer Co., Ltd., trade name “Ultrazex 1020L”, density 0.909 g/cm ³ , MFR 2 g/10 min (190° C.)
· Foaming agent: azodicarbonamide, manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name "Vinihole AC-K3-TA", decomposition temperature: 208 ° C.
Crosslinking aid: 1,9-nonanediol dimethacrylate, manufactured by Kyoeisha Chemical Co., Ltd., trade name “Light Ester 1,9ND”, viscosity 8 mPa s/25°C
・ Phenolic antioxidant: BASF Japan Ltd., trade name “Irganox 1010”

[Example 1]
(Manufacture of thermoplastic resin sheet)
80 parts by mass of TPO, 10 parts by mass of LLDPE (1), 10 parts by mass of polypropylene resin (1), and 1 part by mass of deodorant (1) are kneaded at a temperature of 230°C by a single screw extruder to obtain a 0.5 mm thick product. A thermoplastic resin sheet was obtained.
(Production of crosslinked polyolefin resin foam)
Foamability obtained by mixing 60 parts by mass of polypropylene resin (2), 40 parts by mass of LLDPE (2), 2.5 parts by mass of phenolic antioxidant, 3 parts by mass of crosslinking aid, and 8 parts by mass of foaming agent The composition was melt-kneaded with a single-screw extruder at a temperature of 180° C. to form a foamable sheet. Both surfaces of the foamable sheet were irradiated with 2.0 Mrad of ionizing radiation (electron beam) at an acceleration voltage of 1000 keV to obtain a crosslinked foamable sheet. After that, the crosslinked foamable sheet was supplied to a vertical hot air foaming furnace having an internal temperature of 250° C., and heated and foamed while being stretched to obtain the desired crosslinked polyolefin resin foam.
The thickness, apparent density, degree of cross-linking, and independent cell content of the crosslinked polyolefin resin foam were measured as follows.
(manufacture of laminate)
On one surface of the crosslinked polyolefin resin foam produced as described above, both surfaces were heated to 160° C. by far-infrared heating, passed between lamination rolls with a clearance of 1.0 mm in the thickness of the laminate, and the above thermoplastic resin sheet was attached. to form a laminate. Measurements and evaluations were performed as follows, and the results are shown in Table 1.

[Examples 2 to 5, Comparative Examples 1 to 3]
A laminate was obtained in the same manner as in Example 1, except that the raw material composition of the thermoplastic resin sheet was changed as shown in Table 1. Measurements and evaluations were performed as follows, and the results are shown in Table 1.

(foam thickness)
The thickness of the foams of Examples and Comparative Examples was measured according to JIS K6767.

(Apparent density of foam)
The apparent densities of the foams of Examples and Comparative Examples were measured according to JIS K7222.

(Degree of cross-linking)
A test piece of about 100 mg was taken from the foam, and the mass A (mg) of the test piece was accurately weighed. Next, after immersing this test piece in 30 cm ³ of xylene at 120° C. and leaving it for 24 hours, it is filtered through a 200-mesh wire mesh to collect the undissolved matter on the wire mesh, dried in vacuum, and weighed the insoluble matter. B (mg) was accurately weighed. From the obtained values, the degree of cross-linking (% by mass) was calculated according to the following formula.
Crosslinking degree (mass%) = 100 x (B/A)

(Closed cell rate)
A test piece having a square shape with a side of 5 cm and a constant thickness was cut out from the foamed resin sheet. The thickness of the test piece was measured, the apparent volume V1 of the test piece was calculated, and the weight W1 of the test piece was measured. Next, the apparent volume V2 occupied by the bubbles was calculated based on the following formula. The density of the resin constituting the test piece was 1 g/cm ³ .
Apparent volume occupied by bubbles V2 = V1 - W1
Subsequently, the test piece was submerged in distilled water at 23° C. to a depth of 100 mm from the water surface, and a pressure of 15 kPa was applied to the test piece for 3 minutes. After releasing the pressure in water, remove the test piece from the water, remove the water adhering to the surface of the test piece, measure the weight W2 of the test piece, open cell rate F1 based on the following formula, and closed cell rate F2 was calculated.
Open cell rate F1 (%) = 100 × (W2 - W1) / V2
Closed cell rate F2 (%) = 100-F1

(Odor evaluation)
An odor evaluation test was conducted on each laminate obtained in Examples and Comparative Examples. The conditions of the odor evaluation test were as follows.
Sampling days: Immediately after laminate production Sampling size: 100 cm ²
Odor bottle: 100 cm ² glass container Test temperature: 80°C x 2 hours → cool to 60°C Sniffing temperature: 60°C
Number of people tested: 5 How to sniff the odor: Open the lid of the odor bottle and tilt the odor bottle at an angle of 45° with respect to the horizontal plane. Then, with the nostril placed in the center of the mouth of the odor bottle and the nostril separated from the mouth of the odor bottle by 1 cm, the subject smelled the gas emitted from the odor bottle for 5 to 10 seconds.

Odor evaluation was performed as follows. Aqueous n-butanol solutions having the following n-butanol concentrations were used as odor intensity standard solutions. 150 mL of each of these solutions was weighed into a 1 L glass bottle and used as a reference odor. Then, the odor of the laminate was evaluated based on the odor intensity of these standard odors.
Strength grade 1: n-butanol concentration 0 ml / L
Strength grade 1.5: n-butanol concentration 1.4ml/L
Strength grade 2: n-butanol concentration 2.0 ml / L
Strength grade 2.5: n-butanol concentration 3.6 ml / L
Strength grade 3: n-butanol concentration 6.0 ml / L
Strength grade 3.5: n-butanol concentration 9.0 ml / L
Strength grade 4: n-butanol concentration 18.0 ml / L
Strength grade 4.5: n-butanol concentration 22.7 ml/L
Strength grade 5: n-butanol concentration 30.0 ml / L
Strength grade 5.5: n-butanol concentration 57.0 ml / L
Strength grade 6: n-butanol only

(Vacuum formability)
For the evaluation of vacuum formability, the laminates produced in Examples and Comparative Examples were subjected to vacuum cup forming at 160° C., and then the following judgments were made. If the diameter of the cup is D, the depth is H, and the ratio H/D of the depth H to the diameter D is increased, the laminate is torn or partially whitened. The moldability was evaluated by H/D. Good moldability was evaluated as ◯, and poor moldability was evaluated as ×.
○: H/D≧0.8
×: H/D<0.8

The laminate of each example uses a thermoplastic resin sheet containing 0.2 to 7 parts by mass of a specific deodorant with respect to 100 parts by mass of the thermoplastic resin, and is good in odor evaluation and vacuum moldability evaluation. good results were obtained.
In the laminate of Comparative Example 1, the amount of deodorant in the thermoplastic resin sheet was small, and good results were not obtained in the odor evaluation.
In the laminate of Comparative Example 2, the amount of deodorant in the thermoplastic resin sheet was large, and when vacuum forming was performed, the surface of the laminate was whitened, and the vacuum formability was not good.
In the laminate of Comparative Example 3, the deodorant contained in the thermoplastic resin sheet did not contain porous particles, and good results were not obtained in the odor evaluation.

Claims (9)

Containing 0.2 to 7 parts by mass of a deodorant with respect to 100 parts by mass of the thermoplastic resin,
The deodorant is a thermoplastic resin sheet containing zeolite and hydrazides represented by the following general formula (1) supported on the zeolite .

(Wherein, R represents a hydrogen atom, a group —NH—NH ₂ , or a residue obtained by removing a carboxyl group from a mono-, di-, tri- or tetracarboxylic acid, and n represents an integer of 1 to 4.) 2. The thermoplastic resin sheet according to claim 1, wherein the hydrazide is at least one selected from the group consisting of carbohydrazide, succinic dihydrazide, adipic dihydrazide, and isophthalic dihydrazide. The thermoplastic resin sheet according to claim 1 or 2 , wherein the thermoplastic resin contains an olefinic thermoplastic elastomer. The thermoplastic resin sheet according to any one of claims 1 to 3 , which is a skin material. A laminate comprising a crosslinked polyolefin resin foam and the thermoplastic resin sheet according to any one of claims 1 to 4 laminated on the crosslinked polyolefin resin foam. The laminate according to claim 5 , wherein the crosslinked polyolefin resin foam is obtained by crosslinking and foaming a foamable composition containing a polyolefin resin. The laminate according to claim 6 , wherein the polyolefin resin contains a polypropylene-based resin. A molded article obtained by molding the laminate according to any one of claims 5 to 7 . The molded article according to claim 8 , which is an automobile interior material.