JP3479137B2 - Polypropylene resin composition and foam - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene resin composition. More specifically, it has excellent mechanical strength, heat resistance and flexibility, and is, for example, interior materials for automobiles, vehicles, ships, etc., packaging materials for electrical equipment, precision equipment, etc., and interior materials for construction including general houses. And a foam using the composition.

[0002]

2. Description of the Related Art Polypropylene resins have high crystallinity,
When the temperature exceeds the crystallization temperature, the viscosity sharply decreases as compared with an amorphous resin such as a polystyrene resin, so that it is a resin that is extremely difficult to be adapted to foam molding such as extrusion foaming. For this reason, methods have been carried out in which a polypropylene resin is crosslinked with peroxide, or electron beam is crosslinked, and then heat-foamed.
However, since the foam thus obtained is crosslinked, a large amount of gel is generated when melt-kneading again, which is a serious problem when considering recycling.
On the other hand, in recent years, a method for producing a polypropylene resin having a high viscosity and a melt tension even when melted has been disclosed (for example, Japanese Patent Publication No. 62-121704 and Japanese Patent Publication No. 2-2985).
No. 36, etc.), a study has been made to obtain a non-crosslinked polypropylene-based resin foam having substantially no gel by extrusion molding using such a resin (for example, JP-A-4-363227). , JP-A-5-32815 and JP-A-5-506875). However, the propylene-based resin obtained by these techniques and the foam thereof have a smaller elongation (especially the difference in the foamed molded product) is smaller than that of the resin having a crosslinked structure introduced therein. Therefore, when secondary processing such as stamping molding and vacuum molding is performed using the obtained foam sheet, there is a problem in shaping such as breakage and wrinkles due to insufficient elongation.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to provide good mechanical properties, heat resistance and flexibility and high elongation, and to improve primary formability and secondary workability. Another object is to provide an excellent polypropylene-based resin composition and a foam using the composition.

[0004]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the inventors have conducted extensive studies, and as a result, by using a high melt-strength polypropylene having specific properties,
By improving the primary moldability and further adding a crosslinkable resin composition, a polypropylene resin composition having high viscoelasticity at the time of melting and imparting flexibility and elongation characteristics and excellent processability was found. The present invention has been completed based on such findings.

That is, at least (A) melt tension (MT) at 230 ° C. and melt flow index (M)
FR) is logMT> -1.16 × logMFR +
1.2 (provided that the MFR is in the range of 0.1 to 20) and 50 to 90 parts by weight of high melt tension polypropylene and (B) 10 to 50 parts by weight of the crosslinkable resin composition, and crosslinked. The resin composition (B) is a multi-component copolymer comprising (a) ethylene, a radical-polymerizable acid anhydride and a radical-polymerizable comonomer other than this, and the radical-polymerizable acid anhydride in the multi-component copolymer. Unit derived from the group is 0.1
To 20% by weight and 5 to 40% by weight of units derived from other radically polymerizable comonomers, (b) a polyhydric alcohol compound having at least two hydroxyl groups in the molecule, and ( c) The reaction mixture contains a reaction accelerator, and the molar ratio of the unit of the hydroxyl group in the polyhydric alcohol compound as the component (b) to the unit derived from the radical-polymerizable acid anhydride in the component (a) is 0.01. It is in the range of 10 to 0.001, and the reaction accelerator as the component (c) is 0.001 with respect to 100 parts by weight of the ethylene copolymer as the component (a).
A polypropylene resin composition and a foam obtained by using the composition, characterized in that the content is in the range of 20 to 20 parts by weight.

The high melt-strength polypropylene (A) according to the present invention is characterized by excellent heat resistance and mechanical properties and good primary moldability. Further, the crosslinkable resin composition (B) is flexible and has high strength and large elongation, is flexible and has an extremely high tension at the time of melting, and the moldable temperature is the foaming moldability temperature of the high melt tension polypropylene (A). It has the characteristic of being close. By mixing both components having such characteristics, the original heat resistance, mechanical properties and primary moldability of high melt tension polypropylene are not impaired,
It is possible to provide a material that has flexibility and elongation characteristics and is excellent in secondary moldability. The contents of the present invention will be described in detail below.

First, as the high melt tension polypropylene which is the component (A) of the present invention, a. Use of macromolecular reactions,
b. Adding peroxide, c. Examples thereof include polypropylene partially cross-linked and / or long-chain branched introduced by a method such as irradiation with electron beam or radiation (high energy beam). Further, the high melt tension polypropylene of the present invention has MFR (JIS K7210 Table 1, condition 14) and melt tension (MT: measurement temperature 230 ° C., extrusion speed 15 mm /
Min, take-off speed 6.3 m / min, orifice diameter 2.09
It is important that there is a relationship of the formula (1) between the load (g) applied when the resin strand is pulled under the condition of 5 mm and L / D = 3.8. When the MFR and MT of the high melt tension polypropylene used in the present invention do not satisfy the formula (1), good foam moldability cannot be obtained even if the crosslinkable resin composition as the component (B) is added. log (MT)> − 1.16 × log (MFR) +1.2 (1) Here, the MFR of the high melt tension polypropylene is 0.1 to 0.1.
It is in the range of 20 g / 10 minutes, preferably 0.5 to 10
It is in the range of g / 10 minutes. If the MFR is out of this range and is too small or too large, foam molding is difficult, which is not preferable. As such a high melt tension polypropylene, specifically, component (1): a homopolymer of propylene and / or a copolymer of propylene and another α-olefin, and an unsaturated carboxylic acid and / or a derivative thereof are added. Intramolecularly, a modified polypropylene grafted with 0.01 to 2% by weight and a functional group capable of reacting with a unit derived from an unsaturated carboxylic acid and / or a derivative thereof in the modified polypropylene as the component (2): the component (1). A resin composition in which at least two or more reactive compounds are mixed as essential components. The above component (1)
The polypropylene used in the production of the modified polypropylene of (a) is a propylene homopolymer. (B) Propylene and ethylene and α- having 4 to 10 carbon atoms
A copolymer with an olefin selected from the group consisting of olefins, and the olefins may be used alone or in combination of two or more. Examples of the α-olefin having 4 to 10 carbon atoms include 1-butene, isobutylene and 1-butene.
Pentene, 3-methyl-1-butene, 1-hexene,
3,4-dimethyl-1-butene, 1-heptene, 3-methyl-1-hexene and the like can be mentioned. When the olefin is ethylene, the polymerized ethylene content is 5 (preferably 4)% by weight or less, and the olefin has 4 to 10 carbon atoms.
When it is an α-olefin, its polymerization content is 20
It is preferably (preferably 16)% by weight or less.
The copolymer may be a random copolymer or a block copolymer, but is preferably a block copolymer, more preferably a propylene / ethylene block copolymer.

There are various unsaturated carboxylic acids and / or their derivatives (hereinafter referred to as "unsaturated carboxylic acid compounds") used for obtaining the modified polypropylene as the component (1). For example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, maleic anhydride, itaconic anhydride, endic acid anhydride, citraconic anhydride, 1-butene-3,4 A dicarboxylic acid anhydride, an alkenylsuccinic anhydride having a double bond at the end having at most 18 carbon atoms, an alkadienyl succinic anhydride having a double bond at the end having at most 18 carbon atoms, a monocarboxylic acid dicarboxylic acid An ester etc. can be mentioned. These unsaturated carboxylic acid compounds may be used alone or in combination of two or more. Of these, maleic anhydride and itaconic anhydride are preferably used.

In the modified polypropylene of the component (1), the graft amount of the unsaturated carboxylic acid compound is 0.01
Is in the range of 2 to 2% by weight, preferably 0.03 to 1.0
%, More preferably 0.05 to 0.7% by weight. The graft amount of the unsaturated carboxylic acid compound is 0.
If the amount is less than 01% by weight, the melt tension cannot be sufficiently improved, and a sufficient effect of improving moldability cannot be obtained. 2% by weight
If it exceeds the range, a large amount of gel component is generated, and the physical properties such as appearance and tensile properties of the molded product may be impaired, which is not preferable.

In producing the modified polyolefin used in the present invention, various commonly known methods can be used. That is, the polyolefin is dissolved in a solvent to form a solution, and a radical grafting agent and an unsaturated carboxylic acid or a derivative thereof are mixed and reacted, a solution grafting method, a melting grafting method in which the modification is carried out in an extruder in the absence of a solvent, an electron beam. A radiation grafting method utilizing the above can be used. Further, in order to remove the unreacted unsaturated carboxylic acid compound, it is preferable to perform a step of removing unreacted substances and reaction byproducts by washing with a solvent after the graft modification.

MF of modified polyolefin relating to the present invention
R (according to condition 14 of JIS K-7210 Table 1) is preferably in the range of 0.1 to 500 g / 10 minutes,
It is more preferably 0.1 to 200 g / 10 minutes, and particularly preferably 0.1 to 50 g / 10 minutes. MFR is 0.1
If it is less than g / 10 minutes or more than 500 g / 10 minutes, a composition meeting the object of the present invention cannot be obtained.

Examples of the functional group in the component (2) include those capable of reacting with the unit derived from the unsaturated carboxylic acid compound in the component (1). For example, a hydroxyl group, an amino group, an epoxy group, an isocyanate group and the like are used. Particularly preferred are a hydroxyl group, an amino group and an epoxy group.

Specific examples of the polyhydric alcohol compound having two or more hydroxyl groups in the molecule and its derivative include:
For example, ethylene glycol, diethylene glycol,
Glycols such as triethylene glycol; alcohol compounds such as 1,4 butanediol, 1,6 hexanediol, 1,8 octanediol, 1,10 decanediol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol Arbitol, sorbitol, sorbitan, xylose,
Alamininose, glucose, galactose, sorbose, fructose, palatinose, maltotriose,
Saccharides such as malezitose; saponified products of ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyolefin oligomers having a plurality of hydroxyl groups, ethylene-hydroxyethyl (meth) acrylate [(meth) acrylate are
Methacrylate and acrylate are meant. Less than,
The same] A polymer having a plurality of hydroxyl groups in the molecule such as a copolymer can be used.

The polyhydric alcohol compound is represented by the general formula (1) or (2) (R) _a C (CH ₂ OH) _b ………… (1) (wherein R is hydrogen or carbon). A chain or cyclic alkyl group having 1 to 12 atoms or an aralkyl group is represented, a is an integer of 0 to 2, b is an integer of 2 to 4, and a + b = 4.
Is selected to satisfy. _{) HO-CH 2 CH (OH} ) CH 2 -O- [CH 2 CH (OH) CH 2 -O] n -H ............... (2) ( wherein, n is an integer of 0 And a polyoxyalkylene compound having a structure in which ethylene oxide or propylene oxide is added to the polyhydric alcohol compound represented by the formula (3) and R'-COOH (3) (wherein R'is An organic carboxylic acid compound represented by a chain or cyclic alkyl group having 2 to 25 carbon atoms or an aralkyl group) and the polyglycerol represented by the general formula (2) are dehydrated and condensed. It is also possible to use the obtained polyglycerin ester having two or more hydroxyl groups in the molecule.

Specific examples of these polyoxyalkylene compounds include 1,3-dihydroxypropane, 2,2-dimethyl-1,3-dihydroxypropane, trimethylolethane and 1,1,1-trimethylol. Propane, 1,1,
1-trimethylolhexane, 1,1,1-trimethyloldodecane, 2-cyclohexyl-2-methylol-1,3-dihydroxypropane, 2- (p-methylphenyl) -2-methylol-
1,3-dihydroxypropane, pentaerythritol,
Examples thereof include those obtained by adding ethylene oxide or propylene oxide to glycerin, diglycerin, hexaglycerin, octaglycerin, decaglycerin and the like.

Specific examples of the above-mentioned polyglycerin ester include glycerin monostearate, glycerin monooleate, glycerin monolaurate, glycerin monocaprylate, glycerin monohexanoate and glycerin monophenethyl. Ester, glycerin monopropionate, diglycerin monostearate, diglycerin distearate, diglycerin monooleate, diglycerin monohexanoate, diglycerin dioctanoate, tetraglycerin monostearate, tetraglycerin tristearate Rate, tetraglycerin tetrastearate, tetraglycerin trihexanoate, tetraglycerin monophenethyl ester, hexaglycerin monostearate,
Hexaglycerin distearate, hexaglycerin pentastearate, hexaglycerin trioleate,
Hexaglycerin monolaurate, hexaglycerin pentalaurate, decaglycerin monostearate, decaglycerin octastearate, decaglycerin pentaoleate, decaglycerin dilaurate, pentadecaglycerin distearate, pentadecaglycerin decaoleate, octadeca Examples thereof include glycerin tetrastearate.

Further, the polyhydric alcohol compound is obtained by dehydration condensation of sorbitan or a sorbitan derivative having two or more hydroxyl groups in the molecule and an organic carboxylic acid compound represented by the general formula (3). It is also possible to use sorbitan alkyl esters. As the sorbitan alkyl ester, specifically, for example, sorbitan monostearate, sorbitan monooleate, sorbitan monolaurate, sorbitan monocaprylate, sorbitan monohexanoate, sorbitan monophenethyl ester, sorbitan monopropionate, Examples thereof include sorbitan tristearate and sorbitan tetrastearate. Among these, preferred are those having a valence (number of hydroxyl groups in one molecule) of 3 to 7.

The compounds having a plurality of amino groups in the molecule include ethylenediamine, diaminopropane, diaminobutane, 1,2-dimethyl-1,3-propanamine,
Hexamethylenediamine, 2-methyl-1,5-pentadiamine, diaminoheptane, diaminooctane, 2,
5-dimethyl-2,5-hexanediamine, diaminononane, diaminodecane, diaminododecane, diethylenetriamine, N- (aminoethyl) -1,3-methyldipropanediamine, 3,3'-diamino-N-methyldipropylamine , 3,3′-iminobispropylamine, triethylenetetramine, tris (2-aminoethyl) amine, tetraethylenepentamine, 1,4-diaminocyclohexane, polyethyleneimine and the like. Alternatively, a compound having both an amino group and a hydroxyl group can also be used. For example, ethanolamine 2-hydroxyethylhydrazine, 3-amino-1-propanol,
DL-2-amino-1-propanol, DL-1-amino-2-propanol, 4-amino-1-butanol,
2-amino-1-butanol, 2-amino-1-pentanol, DL-2-amino-1-pentanol, 6-amino-1-hexanol, 2- (2-aminoethoxy)
Ethanol or the like is used.

Examples of the compound having a plurality of epoxy groups in the molecule include sorbitol polyglycidyl ether,
Polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, hydroquinone diglycidyl ether, diglycidyl bisphenol A and its hydrogenated product, phthalic acid diglycidyl ester, trimethylolpropane triglycidyl ether, butanediol diglycidyl ether, epoxidized soybean oil , Epoxidized linseed oil, cyclohexanedimethanol diglycidyl ether, hexanetriol glycidyl ether,
Alicyclic epoxy resin, heterocyclic epoxy resin, brominated epoxy resin, bisphenol A-epichlorohydrin resin, polyfunctional epoxy resin, aliphatic epoxy resin, brominated novolac type epoxy resin, brominated bisphenol A type Examples thereof include epoxy resin, biphenyl type epoxy resin, polyglycidyl amine type epoxy resin, ester type epoxy resin, orthocresol novolac type epoxy resin, phenol novolac type epoxy resin and the like.

Examples of the compound having a plurality of isocyanate groups in the molecule include ethylene diisocyanate, diisocyanate butane, diisocyanate hexane, diisocyanate dodecane, diisocyanate-2-methylpentane and m-phenylenediene. Isocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-
Naphthylene diisocyanate, 4 ', 4', 4 "-triphenylmethane triisocyanate, 4,4 'diphenylmethane triisocyanate, 3,3'-dimethyl-
4,4′-diphenylene diisocyanate, m-xylylene-diisocyanate, p-xylylene-diisocyanate and the like can be mentioned.

The melting point of the compound of component (2) is 30.
It is preferably 0 ° C. or lower. Moreover, these compounds may be used in combination of two or more kinds at the same time.

The amount of the component (2), which is a reactive compound according to the present invention, used is the number of functional groups contained in the reactive compound with respect to the unit derived from the unsaturated carboxylic acid or its derivative contained in the modified polyolefin. Ratio of 1:10
A range of 10: 1 is desirable. More preferably from 1: 7
It is in the range of 7: 1, more preferably in the range of 1: 5 to 5: 1. When the amount of the reactive compound is out of this range and the amount is small, it is impossible to introduce an effective amount of long-chain branching and / or cross-linking structure into the composition, so that the relationship between melt tension and MFR described later is satisfied. It may become difficult and the moldability may become insufficient. Further, when the amount of the reactive compound is out of the above range and is large, it is substantially meaningless in terms of introducing a long-chain branch and / or a crosslinked structure, and further impairs other physical properties of the composition of the present invention. There is a fear that it is not preferable.

Further, the high melt tension polypropylene (A) according to the present invention is, for example, JP-A-62-1217.
04 or polypropylene as produced according to the method disclosed in JP-A-2-298536. That is, in an environment in which the active oxygen concentration is maintained at less than about 15% by volume, polypropylene whose melt tension is improved by irradiating with high-energy radiation or atmospheric oxygen or its equivalent is substantially absent. And in an environment of a temperature range of room temperature to 120 ° C., about 90 to
A half-life of 5 minutes or less in the temperature range of 120 ° C, a half-life of less than 40 minutes in the temperature range of about 60 to about 90 ° C, or a half-life of less than 60 minutes in the temperature range of room temperature to about 60 ° C. Examples thereof include polypropylene having a low decomposition temperature peroxide and a propylene polymer substance that are mixed, and then the melt tension is improved by decomposition of the peroxide.

The high melt tension polypropylene which is the component (A) is used in the range of 50 to 90 parts by weight. It is preferably in the range of 55 to 90 parts by weight, more preferably 60.
˜85 parts by weight. When this high melt tension polypropylene is less than 50 parts by weight, heat resistance, mechanical strength and the like are deteriorated, and when it exceeds 90 parts by weight, flexibility and elongation are lowered, which is not preferable.

In the present invention, the crosslinkable resin composition (B)
The ethylene-based multi-component copolymer which is the component (a) is a multi-component copolymer obtained by copolymerizing ethylene with a radical-polymerizable acid anhydride and another radical-polymerizable comonomer (hereinafter referred to as a third monomer). is there.

Here, as the radically polymerizable acid anhydride,
There are various ones, specifically, for example, maleic anhydride, itaconic anhydride, endic acid anhydride, citraconic anhydride, 1-butene-3,4-dicarboxylic acid anhydride,
Examples thereof include alkenyl succinic anhydride having a double bond at the terminal having at most 18 carbon atoms and alkadienyl succinic anhydride having a double bond at the terminal having at most 18 carbon atoms. These radical-polymerizable acid anhydrides may be used alone or in combination of two or more. Of these, maleic anhydride and itaconic anhydride are preferably used.

In the present invention, the ethylene-based multicomponent copolymer as the component (a) has a unit derived from the radical-polymerizable acid anhydride in the range of 0.1 to 20% by weight, preferably 0.5 to 10% by weight. Is. When the unit derived from the radical-polymerizable acid anhydride is less than 0.1% by weight, the foaming moldability of the obtained resin composition is deteriorated, and the mechanical strength of the foamed product obtained is also unfavorable. On the other hand, if it exceeds 20% by weight, the properties such as flexibility and moisture absorption resistance are impaired, and at the same time, the cost increases, which is not preferable.

The third monomer used in combination with the radical-polymerizable acid anhydride is an ethylenically unsaturated ester compound, an ethylenically unsaturated amide compound, an ethylenically unsaturated acid compound, an ethylenically unsaturated ether compound, an ethylenically unsaturated ester compound. A saturated hydrocarbon compound etc. can be mentioned.

Specifically, the ethylenically unsaturated ester compounds include vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, benzyl (meth) acrylate, methyl fumarate, ethyl fumarate, propyl fumarate, butyl fumarate, dimethyl fumarate, fumarate Diethyl acid, dipropyl fumarate, dibutyl fumarate,
Examples thereof include methyl maleate, ethyl maleate, propyl maleate, butyl maleate, dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, and the like.

As the ethylenically unsaturated amide compound,
(Meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N
-Octyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, etc. can be illustrated.

Examples of the ethylenically unsaturated carboxylic acid compound include (meth) acrylic acid, maleic acid and fumaric acid. Ethylenically unsaturated ether compounds include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Examples thereof include octadecyl vinyl ether and phenyl vinyl ether. Ethylenically unsaturated hydrocarbon compounds and other compounds include styrene and α-
Methylstyrene, norbornene, butadiene, acrylonitrile, methacrylonitrile, acrolein, crotonaldehyde, trimethoxyvinylsilane, triethoxyvinylsilane, vinyl chloride, vinylidene chloride and the like can be mentioned. If necessary, two or more kinds of these third monomers may be used together.

The content of the third monomer in the ethylene copolymer as the component (a) of the crosslinkable resin composition (B) relating to the present invention is 5 to 40% by weight, preferably 10 to 30% by weight. If the content of the third monomer is less than 5% by weight, the elongation property of the resulting foam is not sufficient, which is not preferable, and if it exceeds 40% by weight, the resin becomes too flexible and the handling during molding becomes difficult. As a result, the heat resistance of the resulting foam may decrease, which is not preferable.

MFR of ethylene-based multicomponent copolymer which is the component (a) (according to condition 4 of Table 1 of JIS K-7210)
Is preferably in the range of 0.1 to 500 g / 10 minutes, more preferably 0.1 to 100 g / 10 minutes, and particularly preferably 0.1 to 30 g / 10 minutes. MFR is 0.1g
If it is less than / 10 minutes or exceeds 500 g / 10 minutes, a resin composition meeting the object of the present invention cannot be obtained.
Such an ethylene-based multi-component copolymer can be produced by a generally known method, that is, a polymerization process such as bulk, solution, suspension or emulsion.
Basically, conventional equipment and technology for producing a resin composition can be used.

Examples of the polyvalent alcohol compound having two or more hydroxyl groups in the molecule which is the component (b) of the crosslinkable resin composition include the compounds exemplified above.

The polyhydric alcohol compound having two or more hydroxyl groups in the molecule of component (b) is preferably one having a melting point of 300 ° C. or lower among the above polyhydric alcohol compounds. These polyhydric alcohol compounds may be used alone or in combination of two or more. Among the above-mentioned polyhydric alcohol compounds, the compounds represented by the following general formula (1) or (2) and the general formula (1) or (2) are particularly preferably used.
It is a polyoxyalkylene compound having a structure in which ethylene oxide or propylene oxide is added to the compound represented by. (R) _a C (CH ₂ OH) _b (1) (wherein R represents hydrogen, a chain or cyclic alkyl group having 1 to 12 carbon atoms or an aralkyl group, and a represents Represents an integer of 0 to 2, b represents an integer of 2 to 4, and a + b = 4
Is selected to satisfy. _{) HO-CH 2 CH (OH} ) CH 2 -O- [CH 2 CH (OH) CH 2 -O] n -H ............... (2) ( wherein, n is an integer of 0 .)

The amount of the polyhydric alcohol compound as the component (b) used is in the polyhydric alcohol compound based on the unit derived from the radical-polymerizable acid anhydride contained in the ethylene-based multicomponent copolymer as the component (a). The molar ratio of hydroxyl groups contained in is 0.0
It is in the range of 1-10. In this case, the range of 0.05 to 5 is more preferable. When this molar ratio is less than 0.01, it becomes insufficient to introduce the crosslinked structure into the composition in an effective amount, and when the molar ratio exceeds 10, the crosslinking reaction structure is effectively introduced. In addition to being pointless, it is not preferable because it is costly.

In the present invention, the reaction accelerator which is the component (c) of the crosslinkable resin composition is a carbonyl group contained in a unit derived from the radical-polymerizable acid anhydride contained in the ethylene-based multicomponent copolymer. Is a compound that activates the compound and accelerates the reaction between the hydroxyl group and the acid anhydride.

There are various kinds of reaction accelerators, and one example thereof is a metal salt of an organic carboxylic acid. As the metal salt of an organic carboxylic acid, a metal salt of a fatty acid having 1 to 30 carbon atoms, for example, acetic acid, propionic acid, butyric acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, Behenic acid, benzoic acid, terephthalic acid, etc.
IIA, IIB, IIIB metals (eg, Li, Na,
K, Mg, Ca, Zn, Al, etc.).
Specifically, lithium acetate, sodium acetate, magnesium acetate, aluminum acetate, potassium butyrate, calcium butyrate, zinc butyrate, sodium octanoate, calcium octanoate, potassium decanoate, magnesium decanoate, zinc decanoate, lithium laurate, Sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate, potassium stearate, calcium stearate, zinc stearate, Examples thereof include sodium oleate, sodium behenate, sodium benzoate, potassium terephthalate and the like. Preferably,
Lithium laurate, sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate, potassium stearate, calcium stearate,
Zinc stearate, sodium oleate, etc. are used.

Another example of the metal salt of an organic carboxylic acid is a resin having a metal salt structure of a carboxylic acid. Examples of such resins include metals of Group IA, Group IIA, Group IIB, and Group IIIB of ethylene and radically polymerizable unsaturated carboxylic acid (for example, Li, Na, K, Mg, Ca, Zn, Al, etc.).
Examples thereof include those having a structure in which a salt is copolymerized, or those having a structure in which ethylene and a metal salt of the radical-polymerizable carboxylic acid and another radical-polymerizable unsaturated carboxylic acid and / or a derivative thereof are multi-polymerized. To be

Further, a metal salt of a radically polymerizable unsaturated carboxylic acid (free unsaturated carboxylic acid may be polymerized and neutralized later on a polyolefin resin such as polyethylene, polypropylene or ethylene-propylene copolymer). .) Is graft-polymerized, or a resin having a structure in which a metal salt of a radical-polymerizable carboxylic acid and another radical-polymerizable unsaturated carboxylic acid and / or a derivative thereof are simultaneously graft-polymerized to a polyolefin resin. Can be mentioned. The radically polymerizable unsaturated carboxylic acid and its derivative used here include (meth) acrylic acid, maleic acid,
Fumaric acid, monomethyl maleate, monomethyl fumarate, monoethyl maleate, monoethyl fumarate, monobutyl maleate, monobutyl fumarate, methyl (meth) acrylate, dimethyl maleate, dimethyl fumarate, diethyl maleate, diethyl fumarate, Mention may be made of dibutyl maleate, dibutyl fumarate and the like.

Another example of the reaction accelerator is a tertiary amine compound. Specific examples of the tertiary amine compound used here include trimethylamine, triethylamine, triisopropylamine, trihexylamine, trioctylamine, trioctadecylamine,
Dimethylethylamine, methyldioctylamine, dimethyloctylamine, diethylcyclohexylamine,
N, N-diethyl-4-methylcyclohexylamine and the like can be mentioned.

Another example of the reaction accelerator is a quaternary ammonium salt. Specific examples of the quaternary ammonium salt used here include tetramethylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetramethylammonium bromide, tetraethylammonium bromide, tetraethylammonium iodide and the like.

Further, as another example of the reaction accelerator, IIA
Examples thereof include hydroxides of group IIIB, group IIIB, and group IIIB metals.
Specific examples include calcium hydroxide, magnesium hydroxide, aluminum hydroxide and the like. Also II
Examples thereof include halides of Group A and Group IIB metals. Specific examples thereof include calcium chloride, calcium bromide, magnesium chloride and the like.

Further, oxo acid and IA group, IIA group, IIB
Salts of group IIIB metals can be mentioned as other examples of the reaction accelerator according to the present invention. As a concrete example,
Examples thereof include sodium nitrate, calcium nitrate, zinc nitrate, magnesium nitrate, aluminum nitrate, sodium phosphate and the like.

Furthermore, LiBF ₄ , NaBF ₄ , KBF ₄ , NaPF ₆ ,
KPF ₆ , NaPCl ₆ , KPCl ₆ , NaFeCl ₄ , NaSnCl ₄ , NaSbF ₆ ,
Alkali metal salts of Lewis acids such as KSbF ₆ , NaAsF ₆ and KAsCl ₆ can also be mentioned as other examples of the reaction accelerator. Of the above-exemplified reaction accelerators, metal salts of organic carboxylic acids are preferably used. The reaction accelerators exemplified above are
If necessary, two or more kinds may be used together at the same time.

The amount of these reaction accelerators to be used is 0.1% with respect to 100 parts by weight of the ethylene copolymer as the component (a).
001 to 20 parts by weight, more preferably 0.01 to 20 parts by weight.
It is in the range of 15 parts by weight. If this amount is less than 0.001 part by weight, the reaction becomes too slow and it becomes difficult to effectively introduce the crosslinked structure into the resin composition. Further, if this amount is more than 20 parts by weight, it is meaningless in terms of improving the reaction rate and is not economically preferable.

The above crosslinkable resin composition is used in the range of 10 parts by weight or more and less than 50 parts by weight. The range is preferably 10 parts by weight or more and less than 45 parts by weight, more preferably 15 parts by weight.
It is in the range of not less than 40 parts by weight and not less than 40 parts by weight. When this crosslinkable resin composition is 50 parts by weight or more, heat resistance, mechanical strength and the like are deteriorated, and when it is less than 10 parts by weight, flexibility and elongation are lowered, which is not preferable.

As a method for producing the crosslinkable resin composition, various commonly known resin mixing methods can be used. As a specific example, a Henschel mixer or a tumbler may be used for dry blending, and a kneader such as a pressure kneader, a roll, a Banbury mixer, a static mixer, or a screw extruder may be used. It may be melt-kneaded. At this time, a uniform mixture can be obtained by previously dry-blending and melt-kneading the resulting mixture. As the method for obtaining the resin composition of the present invention from the high melt tension polypropylene of the component (A) and the crosslinkable resin composition of the component (B), the above-mentioned various resin mixing methods can be used. Further, in the production stage of the crosslinkable resin composition, it is possible to mix the high melt tension polypropylene of the component (A).

It is also possible to melt mix the components during the primary processing and molding of the resin composition of the present invention. That is, it is also possible to mix (dry blend) the respective components in the form of pellets, powder, etc., and melt-mix using the stage of producing the foam. In the polypropylene resin composition thus obtained, various additives, compounding agents, fillers and the like can be used as long as the characteristics of the composition are not impaired. Specific examples of these are antioxidants (heat stabilizers), ultraviolet absorbers (light stabilizers), antistatic agents, antifogging agents, flame retardants, lubricants (slip agents, antiblocking agents), glass fillers, etc. Inorganic fillers, organic fillers, reinforcing agents, colorants (dyes, pigments), and fragrances. The polypropylene resin composition obtained as described above has an MFR at 230 ° C. in the range of 0.1 to 20 g / 10 minutes, preferably 0.5 to 15 g / 10 minutes, more preferably 0.5 to 10 g. It is necessary to be in the range of / 10 minutes. Outside this range, the MFR is too small,
If it is too large, foam molding becomes substantially difficult.

The polypropylene resin composition of the present invention comprises
Although the main components are the high melt tension polypropylene (A) and the crosslinkable resin composition (B), various polyolefin resins can be blended according to the use and the purpose within the range where the object of the present invention is not lost. . Examples of such polyolefin resins include homopolymers such as polyethylene, polypropylene, polyisoprene, polybutene, poly-3-methylbutene-1, poly-4-methylpentene-1, polybutadiene and polystyrene.
Further, copolymers of the respective comonomers constituting these homopolymers, for example, ethylene-propylene copolymers; butene-1, 4-methylpentene-1, hexene-1, octene-1, etc. A chain resin composition; a copolymer such as a propylene-ethylene block copolymer may also be mentioned. Further, a mixture of the above resins, a graft copolymer, a block copolymer, an ethylene-vinyl acetate copolymer, and the like can be mentioned. The blending amount of the above-mentioned polyolefin resin is such that the composition mainly contains the high melt tension polypropylene (A) and the crosslinkable resin composition (B) as components.
The amount is preferably 200 parts by weight or less with respect to 100 parts by weight. When the blending amount of the polyolefin resin exceeds 200 parts by weight, the flexibility, heat resistance, mechanical strength, foam moldability and the like which the polypropylene resin composition of the present invention originally has may not be exhibited.

The polypropylene resin composition of the present invention comprises
The foam can be produced by using various methods already known. For example, there is a so-called gas foam molding method in which a volatile foaming agent is added to a polypropylene resin composition, melt-kneaded under pressure, and extruded into atmospheric pressure. . Examples of the volatile blowing agent used here include hydrocarbons such as propane, butane, pentane, isobutane, hexane and butadiene, and methyl chloride, methylene chloride, dichlorofluoromethane, dichlorotetrafluoroethane, 1,1,1. Halogenated hydrocarbons such as 1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane, and 1,2-dichloro-2,2,2-trifluoroethane are gaseous compounds at room temperature and atmospheric pressure. Can be mentioned. Further, a so-called extrusion foam molding method is used, in which a heat-decomposable foaming agent is kneaded with the polypropylene resin composition of the present invention, melt-kneaded under pressure at a decomposition temperature of the heat-decomposable foaming agent or higher, and extruded into atmospheric pressure. You can also Examples of the heat decomposition type foaming agent used here include:
Inorganic compound-based foaming agents such as sodium hydrogen carbonate and potassium hydrogen carbonate, and mixtures thereof with an organic carboxylic acid or an organic carboxylic acid salt, azodicarbonamide, azobisisobutyronitrile, paratoluenesulfonyl hydrazide, etc. It is also possible to use an organic compound-based foaming agent as a main component.

As another foaming method, the above heat-decomposable foaming agent and the polypropylene-based resin composition of the present invention are melt-kneaded at a temperature not higher than the decomposition temperature of the foaming agent, extrusion-molded, and then this extrusion-molded product. It is also possible to obtain a foam by a heating foaming method in which is charged into a heating furnace and heated above the decomposition temperature of the foaming agent to foam. Among the above methods, for the purpose of the present invention, a gas foaming method or an extrusion foaming method using an inorganic thermal decomposition type foaming agent is particularly recommended. The foamed product of the present invention thus obtained is characterized by excellent heat resistance and mechanical strength, flexibility and particularly high elongation. Therefore, by using the foamed body of the present invention formed into a sheet shape, for example, it becomes possible to manufacture a good automobile member such as a door trim by stamping molding, vacuum forming or the like.

[0053]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto. (Evaluation method) Melt tension (hereinafter referred to as MT) Measurement temperature 230 ° C., extrusion speed 15 mm / min, take-up speed 6.3 m / min, orifice diameter 2.095 mm, L / D
= Load (g) applied when the resin strand is pulled under the condition of 3.8. Melt Flow Index (hereinafter referred to as MFR) JIS K7210 Table 1 Condition 14. Tensile breaking elongation Tensile speed 200 mm / mi according to JIS K7113
n. I went there. Appearance of foam The foam sheet was visually observed and evaluated as follows. ◯: There is no surface roughness or open cell parts, and the whole has a homogeneous property. Poor: There are rough and open cell portions on the surface, and the whole does not have homogeneous properties. Evaluation of heat resistance The dimensions of the foam sheet (100 × 100 mm square) of the present invention in the M direction (take-off direction) and the T direction (perpendicular direction of take-up) were measured, and the measurements were made in a gear oven at 140 ° C.
Leave for hours. After that, the dimension after heating was measured and the rate of change in heating dimension was calculated by the following formula. Heating dimensional change rate = 100 (dimension before heating-dimension after heating) / dimension before heating Stamping evaluation MCM500 injection compression molding machine manufactured by Takahashi Seiki Seisakusho was used as a molding machine. The foam sheet of the present invention was previously set between molds and was connected to the lower mold by using a flat plate mold having a 600 × 600 mm square and a mold clearance of 5 mm at the time of mold clamping. Molten resin (MFR50g / 10min impact-resistant polypropylene) is injected from a nozzle at a resin temperature of 200 ° C through a hot runner from an injection molding machine, and stamping molding is performed by clamping, pressurizing, and cooling to give an appearance of the molded product. evaluated. Good: Good x: A corner was torn. X: The foam was crushed.

Reference Example 1 A modified polypropylene (PP1) was produced by graft-modifying a propylene homopolymer with maleic anhydride. The modified polypropylene (PP1) obtained had an MFR of 2.5 g / 10 min and a maleic anhydride-derived unit content of 0.23% by weight. 50 parts by weight of the above modified polypropylene, 50 parts by weight of homopolypropylene having an MFR of 3.0 g / 10 min, and trimethylolpropane triglycidyl ether as a reactive compound (Epiclon 725 epoxy equivalent 14 manufactured by Dainippon Ink and Chemicals, Inc.)
1) 0.35 parts by weight (epoxy group / maleic anhydride =
3.0), 0.1 part by weight of calcium stearate as a reaction accelerator, 0.1 part by weight of BHT, and 1.0 part by weight of talc (average particle size of about 2.0 μm) were mixed. For mixing, after dry blending the 6 components with a Henschel mixer, use a 37 mmφ same-direction twin-screw extruder to
The mixture was melt-kneaded at ℃ and pelletized. The MFR of the mixture was 1.7 g / 10 minutes and the MT was 17 g. This satisfies the following formula (1). This was designated as high melt tension polypropylene (1). logMT> -1.16 × logMFR + 1.2 (1)

(Reference Examples 2 to 6) High melt tension polypropylenes (2) to (6) were produced in the same manner as in Reference Example 1 using the propylene polymer compositions shown in Table 1. The results are shown in Table 1. All of them showed good foam moldability. In addition,
Explanations of symbols and words in Table 1 are as follows. Functional group ratio = ratio of the number of functional groups in the reactive compound to the units derived from the unsaturated carboxylic acid compound in the modified polyolefin PP1 MFR 2.5 g / 10 minutes, 0.23 weight units derived from maleic anhydride % Of modified homopolypropylene PP2 MFR 3.2 g / 10 minutes, modified random polypropylene in which the unit derived from maleic anhydride is 0.34% by weight [propylene-ethylene (2% by weight) copolymer] PP3 MFR 4.2 g / 10 minutes, modified random terpolymer having 0.42% by weight of a unit derived from maleic anhydride [propylene-ethylene (2% by weight) -1-butene (4% by weight) copolymer] PP4 MFR 3.0 g / 10 minutes of homopolypropylene PP5 MFR 5.0 g / 10 minutes of random polypropylene [propylene-ethylene (2 wt. ) Copolymer] PP6 MFR2.2g / 10 min homopolypropylene TMG = trimethylolpropane triglycidyl ether TMP = trimethylolpropane DPT = dipentaerythritol HMA = hexamethylenediamine DA = n-decanol

Reference Example 7 Homopolypropylene (P1) was used instead of the modified polypropylene (PP1) in Reference Example 1.
A composition was obtained in the same manner as in Reference Example 1 except that P4) was used.

Reference Example 8 A composition was obtained in the same manner as in Reference Example 1 except that the reactive compound of Reference Example 1 was not added.

Reference Example 9 A composition was obtained in the same manner as in Reference Example 1 except that n-decanol was used in place of trimethylolpropane glycidyl ether which was the reactive compound of Reference Example 1.

Reference Example 10 A composition was obtained in the same manner as in Reference Example 1 except that the amount of trimethylolpropane, which was a reactive compound of Reference Example 2, was reduced as shown in Table 1.

(Reference Example 11) Using a high-pressure polyethylene production facility having a tank reactor, MFR (JISK72
10 Table 1 Condition 4) 10 g / 10 minutes, 3.0% by weight of maleic anhydride-derived units and 27% by weight of methyl acrylate-derived units, a multi-component copolymer of ethylene and maleic anhydride and methyl acrylate. A polymer was produced. The composition of the copolymer was determined by infrared absorption spectrum. As a metal salt of 100 parts by weight of the copolymer, 1.6 parts by weight of pentaerythritol (hydroxyl group / acid anhydride group = 1.5) and an organic carboxylic acid, MFR (JIS K
7210 Table 1, condition 4) 3.0 g / 10 minutes, density 0.9
4 g / cm ³ partially neutralized product of ethylene-methacrylic acid copolymer (a) (methacrylic acid content 18% by weight, copolymer obtained by neutralizing about 10% of the methacrylic acid <sodium salt>) 5 parts by weight were mixed. When mixing,
30m after blending 3 components with Henschel mixer
The mixture was melt-kneaded and pelletized at 200 ° C. by using an mφ different-direction biaxial extruder. This was designated as a crosslinkable resin composition (11).

Reference Examples 12 to 16 A crosslinkable resin composition (12 to 16) was prepared in the same manner as in Reference Example 11 using the ethylene-based multi-component copolymer, polyhydric alcohol and reaction accelerator shown in Table 2.
16) was produced. The symbols in Table 2 are explained below. MA = methyl acrylate BA = butyl acrylate MMA = methyl methacrylate VA = vinyl acetate PE = pentaerythritol HEA ethylene and 2-hydroxyethyl acrylate (8% by weight) copolymer TM = trimethylolpropane DG = decaglycerin PG-CT pentaglycerin Caprylic acid monoester PE-45P Propylene oxide (4.5 mol) adduct of pentaerythritol DG-80E Ethylene oxide (8.0 mol) adduct of decaglycerin Metal salt (a) Ethylene-methacrylic acid (18% by weight) Copolymer Na
Salt (10% molar neutralization of methacrylic acid), MFR (JIS-
K7210, Table 1, Condition 4) 3.0 g / 10 min Metal salt (b) = Sodium stearate

Reference Example 17 Reference Example 1 except that the polyhydric alcohol of the crosslinkable resin composition (11) of Reference Example 11 was omitted.
Prepared as in 1.

Reference Example 18 The procedure of Reference Example 11 was repeated except that the reaction accelerator of the crosslinkable resin composition (11) of Reference Example 11 was omitted.

Example 1 70 parts by weight of the high melt tension polypropylene (1) of Reference Example (1) and 30 parts by weight of the crosslinkable resin composition (11) of Reference Example (11) were mixed. In mixing, after dry-blending the two components with a tumbler mixer, use a 30 mmφ different-direction biaxial extruder,
The mixture was melt-kneaded at 200 ° C. and pelletized. The polypropylene resin composition obtained had a tensile elongation at break of 270% and was flexible. Next, the polypropylene resin composition pellets were kneaded at 220 ° C. in a tandem extruder composed of a 50 mmφ extruder and a 65 mmφ extruder, and chlorodifluoromethane and 1-chloro-containing volatile foaming agents were added in the middle of the extruder.
13 parts by weight of a mixture of 40:60 (weight basis) of 1,1-difluoroethane was press-fitted, and a lip width of 600 mm and a pressure of 0.
From the T-shaped die with a gap of 4mm, die temperature 160 ℃
Was extruded into the atmosphere to produce a foamed sheet. The molding could be carried out without any problems. The apparent density of the obtained foamed sheet was 0.04 g / cm ³ , and the appearance and the bubble state were good. The stamping evaluation of the foamed sheet was also good.

Examples 2 to 8 Using the high melt tension polypropylene and the crosslinkable resin composition shown in Table 3, Example 1 was used.
The polypropylene resin composition (2-8) was manufactured similarly to the above. In all the polypropylene resin compositions, the elongation was good, and the appearance of the foam and the stamping evaluation were good.

(Comparative Example 1) The procedure of Example (1) was repeated except that the crosslinkable resin composition of Example (1) was not added. The tensile elongation at break was as low as 40%. The foam had a good appearance, but the corners were torn in the stamping evaluation.

(Comparative Examples 2 to 4) Production was carried out in the same manner as in Example (1) except that the resins shown in Table 3 were used instead of blending the crosslinkable resin composition of Example (1). When a foam was produced and the appearance was observed, open cells were partially seen.

Comparative Example 5 A resin was prepared in the same manner as in Example (1) except that the resin of Reference Example (7) was used instead of blending the high melt tension polypropylene of Example (1). Bubbles were not stable and a foamed sheet with a good appearance could not be obtained.

(Comparative Examples 6 to 8) Instead of blending the high melt tension polypropylene of Example (1), Reference Examples (8 to 1)
The procedure of Example (1) was repeated except that the resin of (0) was used. Bubbles were not stable and a foamed sheet with a good appearance could not be obtained.

(Comparative Example 9) A product was prepared in the same manner as in Example (1) except that the high melt tension polypropylene of Example (1) was not added. The foam was crushed during stamping of the foam.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

[Table 3]

[0074]

EFFECT OF THE INVENTION The present invention provides a polypropylene resin composition having good mechanical properties, heat resistance and flexibility, and excellent in foam moldability. Further, the foam obtained using the polypropylene resin composition of the present invention is also excellent in secondary processability, interior materials for automobiles, vehicles, ships, etc., electrical equipment, packaging materials for precision equipment, etc. Alternatively, it can be widely used for applications such as interior materials for construction including general houses.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08L 71:02) (72) Inventor Hirotaka Tagoshi, Oita City, Oita Prefecture 2 Nakanosu, Showa Denko K.K. (56) References JP-A-8-143743 (JP, A) JP-A-8-27350 (JP, A) JP-A-7-241947 (JP, A) JP-A-7-70402 (JP, A) Kaihei 6-166777 (JP, A) JP 6-87988 (JP, A) JP 6-57062 (JP, A) JP 2-298536 (JP, A) JP 49-5150 ( JP, A) Tokuheihei 5-506875 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08 C08J 9 / 00

Claims (13)

(57) [Claims] 1. Melt tension (MT) and melt flow index (MFR) at least (A) 230 ° C.
, LogMT> -1.16 × logMFR + 1.2
(MFR is in the range of 0.1 to 20.) 50 to 90 parts by weight of high melt tension polypropylene having a relationship of (B) and 10 to 50 parts by weight of the crosslinkable resin composition (B). The composition (B) is (a) a multi-component copolymer comprising ethylene, a radical-polymerizable acid anhydride and a radical-polymerizable comonomer other than the above, and the radical-polymerizable acid anhydride group in the multi-component copolymer is Unit of origin is 0.1
20% by weight and 5 to 40% by weight of units derived from other radically polymerizable comonomers, an ethylene-based multi-component copolymer, (b) a polyhydric alcohol compound having at least two hydroxyl groups in the molecule, and (c ) The reaction mixture contains a reaction accelerator, and the molar ratio of the unit of the hydroxyl group in the polyhydric alcohol compound of the component (b) to the unit derived from the radical-polymerizable acid anhydride in the component (a) is 0.01 to. 10 parts by weight, and 0.001 with respect to 100 parts by weight of the ethylene copolymer whose component (c) is the reaction accelerator which is component (a).
The polypropylene-based resin composition is characterized by being in the range of 20 parts by weight. 2. The MFR at 230 ° C. is 0.1 to 20.
The polypropylene-based resin composition according to claim 1, which is g / 10 minutes. 3. The high melt tension polypropylene of component (A) is used as component (1): a homopolymer of propylene and / or a copolymer of propylene and another α-olefin, an unsaturated carboxylic acid and / or a derivative thereof. Modified polypropylene grafted with 0.01 to 2% by weight of component (2):
A reactive compound having at least two or more functional groups capable of reacting with a unit derived from the unsaturated carboxylic acid and / or its derivative in the modified polypropylene as the component (1), as an essential component The polypropylene resin composition according to claim 1 or 2. 4. The high melt tension polypropylene (A) is substantially free of atmospheric oxygen or its equivalent and is from room temperature to
Under an environment of a temperature range of 120 ° C., about 90 to 120
Half-life of 5 minutes or less in the temperature range of ℃, about 60 to about 90 ℃
A low-decomposition temperature peroxide having a half-life of less than 40 minutes within the temperature range of about 60 minutes, or a half-life of less than 60 minutes within the temperature range of room temperature to about 60 ° C., and the propylene polymer material is then mixed. The polypropylene-based resin composition according to claim 1 or 2, which is polypropylene having a melt tension improved by decomposition of an oxide. 5. The crosslinkable resin composition (B), which is the component (c) of the reaction accelerator is a metal salt of a polymer containing a carboxyl group or a metal salt of an organic carboxylic acid. The polypropylene-based resin composition described in 1. 6. A component (2) of high melt tension polypropylene.
The polypropylene-based resin composition according to claim 3, wherein the functional group in is a hydroxyl group. 7. A component (2) of high melt tension polypropylene.
The polypropylene-based resin composition according to claim 3, wherein the functional group in is an amino group. 8. A component (2) of high melt tension polypropylene.
The polypropylene-based resin composition according to claim 3, wherein the functional group in is an epoxy group. 9. A component (1) of high melt tension polypropylene.
The ratio of the units derived from the unsaturated carboxylic acid and the derivative thereof in the modified polypropylene and the number of the functional groups in the component (2) is 1:10 to 10: 1. The polypropylene resin composition according to any one of claims. 10. The polypropylene resin composition according to claim 3 or 6 or 9, further comprising a reaction accelerator added to components (1) and (2) of the high melt tension polypropylene. 11. The polypropylene resin composition according to claim 10, wherein the reaction accelerator is an organic carboxylic acid metal salt and / or a tertiary amine. 12. The component (b) of the crosslinkable resin composition (B).
The polyhydric alcohol compound is a compound represented by the following general formula (1) or (2) and a structure obtained by adding ethylene oxide or propylene oxide to the compound represented by the general formula (1) or (2). The polypropylene resin composition according to claim 1, which is a polyoxyalkylene compound. (R) _a C (CH ₂ OH) _b (1) (wherein R represents hydrogen, a chain or cyclic alkyl group having 1 to 12 carbon atoms or an aralkyl group, and a represents Represents an integer of 0 to 2, b represents an integer of 2 to 4, and a + b = 4
Is selected to satisfy. _{) HO-CH 2 CH (OH} ) CH 2 -O- [CH 2 CH (OH) CH 2 -O] n -H ............... (2) ( wherein, n is an integer of 0 .) 13. A foam obtained by foam-molding the polypropylene resin composition according to claim 1.