JP2000026640A - Polyolefin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyolefin foam durable to various molding conditions during thermal shaping molding and excellent in mechanical properties and recyclability by heating a composition containing a specified polyolefin resin, a specified ethylene/propylene/nonconjugated diene copolymer, a PP, a peroxide, and a blowing agent in a specified ratio. SOLUTION: This foam is obtained by heating a composition containing 5-90 pts.wt. peroxide-decomposable polyolefin resin (e.g. propylene polymer) having a melt flow rate of 0.1-80 g/10 min; 9-94 pts.wt. peroxide-crosslinkable ethylene/propylene/nonconjugated diene copolymer having a diene content of 10-25 g/100 g in terms of an iodine value and a Mooney viscosity ML1+4 (100 deg.C) of 10-300; 1-40 pts.wt. low-molecular-weight PP having a number-average molecular weight of 1,000-15,000 and a melting point of 135-145 deg.C (the total of the three components is 100 pts.wt.); 0.5-2.5 pts.wt. peroxide [e.g. 1,3-bis(t- butylperoxyisopropyl)benzene]; and 3-25 pts.wt. blowing agent (e.g. azodicarbonamide).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin-based foam, and more particularly, to an olefin-based foam which has improved mechanical properties against tensile elongation and compression required during thermoforming, and is suitable for interior skin materials of automobiles. About.

[0002]

2. Description of the Related Art In recent years, the recycling of various components constituting automobiles has been promoted, and the recycling of interior materials such as instrument panels, door panels, consoles and the like has been demanded. By the way, these interior materials are composite materials obtained by integrally molding members such as a skin material, a backing foam, and a base material by thermoforming such as vacuum molding and injection molding. If each member such as a base material is formed of the same material, it is effective to improve the recyclability of the material.
Therefore, in recent years, olefin-based materials have been used as skin materials, and in order to promote the recycling of these interior materials, it is required that the materials of the backing foam and the base material be unified to olefin-based materials. .

[0003] In response to these requirements, an olefin-based foamed material having excellent heat resistance and flexibility, as well as excellent recyclability and thermoforming processability, is disclosed in JP-A-2-2557.
No. 38, JP-A-3-47849, and the like. These olefin-based foam materials are excellent in flexibility and recyclability.

[0004]

However, in recent years, the use conditions for each member have become stricter, and there has been a demand for thermoforming workability in heat shaping at a higher temperature than in the past. For example, foams that have excellent mechanical properties that can withstand tensile loads and compressive loads from low pressure to high pressure under severe heating atmosphere, and that show good cushioning properties even after forming by heating shaping It has been demanded. Therefore, there is a demand for the appearance of a foam having higher performance than before, which satisfies the recyclability, heat resistance, and flexibility required for automotive interior materials and can withstand the molding conditions encountered during molding by heat shaping.

Accordingly, the present invention solves the above-mentioned problems of the prior art, is excellent in recyclability, is excellent in mechanical properties against tensile elongation and compression, and can withstand various molding conditions encountered during heat forming. An object is to provide an olefin-based foam.

[0006]

In order to achieve the above object, the olefin foam of the present invention comprises: (a) a peroxide decomposable polyolefin resin having a melt flow rate of 0.1 to 80 g / 10 min. 5 to 90 parts by weight, (b) the diene content is 10 to 25 g / 100 in iodine value.
g, and Mooney viscosity ML _{1 + 4} (100 ° C.) is 10 to 300.
9 to 94 parts by weight of a peroxide crosslinked ethylene-propylene-nonconjugated diene copolymer of (c) having a number average molecular weight of 1,000 to 15,000 and a melting point of 1
1 to 40 parts by weight of low molecular weight polypropylene at 35 to 145 ° C (where the total of (a) + (b) + (c) is 100 parts by weight) (d) Peroxide 0.5 to 2.5 Parts by weight (e) a foaming composition containing 3 to 25 parts by weight of a foaming agent.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The olefin foam of the present invention (hereinafter referred to as "foam of the present invention") will be specifically described below.

The foam of the present invention comprises a polyolefin resin (a), an ethylene-propylene-nonconjugated diene copolymer (b), a low molecular weight polypropylene (c), a peroxide (d) and a foaming agent (e). An olefin foam obtained by heating a foamable composition containing the olefin foam.

The polyolefin resin as the component (a) of the foamable composition for obtaining the foam of the present invention is composed of a peroxide-decomposable polyolefin. The polyolefin resin (a) is a homopolymer or copolymer of an α-olefin having 3 to 20 carbon atoms, and is mixed with a peroxide (d) described below and kneaded under heating. , Which is thermally decomposed. Other α-olefins having 3 to 20 carbon atoms include, for example, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-
Hexene, 1-octene, 1-nonene, 1-decene, 1
-Undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene,
-Heptadecene, 1-octadecene, 1-nonadecene,
1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4
-Dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-
Hexene, 9-methyl-1-decene, 11-methyl-1
-Dodecene, 12-ethyl-1-tetradecene, etc., and these are used alone or in combination of two or more. The content of the α-olefin having 3 to 20 carbon atoms in the polyolefin resin (a) is 50 to 10
0 mol%.

Specific examples of the polyolefin resin (a) include the following homopolymers and copolymers. (1) Homopolymer of propylene (2) Random copolymer of propylene and 10 mol% or less of other α-olefin (3) Block copolymer of propylene and 30 mol% or less of other α-olefin (4) 1-butene homopolymer (5) Random copolymer of 1-butene and 10 mol% or less of other α-olefin (6) 4-methyl-1-pentene homopolymer (7) 4 Copolymer of -methyl-1-pentene and 20 mol% or less of other α-olefin

Among these, homopolymers of propylene and propylene-α-olefin copolymers are preferred because a foam having excellent heat resistance can be obtained.

In the present invention, the polyolefin resin (a) has a melt flow rate (MFR) of 0.1 to 8
0 g / 10 min, more preferably 1 to 10 g / 10 min. In the present invention, the melt flow rate is 230 ° C., based on ASTM D1238.
This is a value measured under the condition of a 16 kg load. By using the propylene polymer (a) having a melt flow rate within the above range, a foam having excellent heat moldability during heat shaping can be obtained.

Further, in the present invention, the polyolefin resin (a) is characterized in that the polyolefin resin (a) is excellent in heat resistance and recyclability, and is capable of obtaining a foam having excellent moldability during heat shaping. ), Ethylene-propylene-nonconjugated diene copolymer (b) and low molecular weight polypropylene (c) in a total of 100 parts by weight,
The compounding ratio is preferably 90 to 90 parts by weight, more preferably 20 to 60 parts by weight, particularly preferably 20 to 40 parts by weight.

The ethylene-propylene-nonconjugated diene copolymer which is the component (b) of the foamable composition for obtaining the foam of the present invention is a peroxide-crosslinked ethylene-propylene-nonconjugated diene copolymer. It is united. As the non-conjugated diene which is a component of the ethylene-propylene-non-conjugated diene copolymer (b), dicyclopentadiene or ethylidene norbornene is preferable.

The content ratio of ethylene / propylene in the ethylene-propylene-non-conjugated diene copolymer (b) is preferably in the range of 95/5 to 55/45.
Further, the non-conjugated diene content in the ethylene-propylene-non-conjugated diene copolymer (b) is an iodine value of 10 to 25 g / 100 g.
Those having a range of 0 to 23 g / 100 g are preferred.

In the present invention, the ethylene-propylene-nonconjugated diene copolymer (b) has a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of from 10 to 300, and particularly preferably from 30 to 300. Those having a range of 100 to 100 are preferable.

In the present invention, ethylene-propylene-
If the non-conjugated diene, the Mooney viscosity and the iodine value of the non-conjugated diene copolymer (b) are within the above ranges, even in a very severe heating atmosphere which is incurred during molding by heating shaping,
A foam having excellent mechanical properties capable of withstanding a tensile load or a compressive load can be obtained.

According to the present invention, it is possible to obtain a foam having excellent mechanical properties which is excellent in flexibility and can withstand a tensile load and a compressive load even in an extremely severe heating atmosphere applied during thermal working. In this respect, this ethylene-propylene-non-conjugated diene copolymer (b) is a total of 100 parts by weight of the polyolefin resin (a), the ethylene-propylene-non-conjugated diene copolymer (b) and the low molecular weight polypropylene (c). In, 9-
A compounding ratio of 94 parts by weight, preferably a compounding ratio of 30 to 70 parts by weight, particularly preferably a compounding ratio of 40 to 70 parts by weight.

The low molecular weight polypropylene which is the component (c) of the expandable composition for obtaining the foam of the present invention has a number average molecular weight in the range of 1,000 to 15,000, and preferably has a number average molecular weight of 1,000 to 1,000. It is in the range of 10,000.

The low molecular weight polypropylene (c) has a melt flow rate in the range of 100 to 300 g / 10 minutes, preferably in the range of 150 to 250 g / 10 minutes. Further, the melting point is in the range of 135 ° C to 145 ° C, preferably in the range of 135 to 140 ° C.

In the present invention, the low molecular weight polypropylene (c) is used in a total of 100 parts by weight of the polyolefin resin (a), the ethylene-propylene-nonconjugated diene copolymer (b) and the low molecular weight polypropylene (c). , 1 to 40 parts by weight, preferably 1 to 30 parts by weight.
A compounding ratio of 1 part by weight, particularly 1 to 20 parts by weight is preferable.

In the present invention, in addition to the above-mentioned polyolefin resin (a), ethylene-propylene-non-conjugated diene copolymer (b) and low molecular weight polypropylene (c), the foamable composition further comprises other components. May be blended. For example, an ethylene polymer, an ethylene-α-olefin copolymer, or the like may be blended as needed, as long as the object of the present invention is not impaired. Specific examples of the ethylene polymer or the ethylene-α-olefin copolymer include low-pressure or high-pressure polyethylene, or ethylene and another monomer such as another α-olefin or a vinyl monomer such as vinyl acetate or ethyl acrylate. And a copolymer with a polymer. As other α-olefins, for example, ethylene, propylene, 1-butene, 1-pentene, 1-
Hexene, 1-octene, 1-decene, 1-dodecene,
4-methyl-1-pentene, 3-methyl-1-pentene and the like. Also, when the ethylene polymer contains other monomers, the content of other monomers other than ethylene,
Usually, it is 10 mol% or less, and the content of monomers other than ethylene in the ethylene-α-olefin copolymer is usually 45 mol% or less.

When the foamable composition contains the ethylene polymer or the ethylene-α-olefin copolymer, the amount of the ethylene polymer or the ethylene-α-olefin copolymer is determined by the amount of the polyolefin resin (a), Ethylene-
For a total of 100 parts by weight of the propylene-nonconjugated diene copolymer (b) and the low molecular weight polypropylene (c),
Usually, the amount is 30 parts by weight or less.

The foamable composition contains a peroxide (d) and a foaming agent (e) to constitute the foam of the present invention by crosslinking and foaming. The peroxide (d) is a component for heat crosslinking of the foamable composition, and is preferably an organic peroxide. Specific examples of the organic peroxide include dicumyl peroxide and di-tert.
-Butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-
Dimethyl-2,5-di (tert-butylperoxy)
Hexin-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert
-Butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide,
p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperbenzoate, t
tert-butyloxyisopropyl carbonate, diacetyl peroxide, lauroide peroxide, tert
-Butyl cumyl peroxide and the like.

In the foamable composition used in the present invention, the mixing ratio of the peroxide (d) is appropriately determined in consideration of the balance between the cell diameter of the foam obtained, the gel fraction, and the like. 100 total of components (a), (b) and (c)
It is used in a blending ratio of 0.5 to 2.5 parts by weight, particularly preferably 0.5 to 2 parts by weight, based on part by weight.

In the present invention, at the time of crosslinking using the peroxide (d), the gel fraction of the obtained foam can be adjusted by using a crosslinking aid. Specific examples of the crosslinking aid include sulfur, p-quinonedioxime, p,
p'-benzoylquinone dioxime, N-methyl-N-
4-dinitrosoaniline, nitrosobenzene, diphenylguanidine, trimethylolpropane-N, N'-m
A peroxy crosslinking aid such as phenylenedimaleimide or a polyfunctional methacrylate monomer such as divinylbenzene, triallyl cyanurate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, allyl methacrylate, vinyl butyrate, Examples thereof include polyfunctional vinyl monomers such as vinyl stearate.

(E) of the foamable composition used in the present invention
As the foaming agent as a component, a pyrolytic foaming agent that generates a gas by thermal decomposition is preferable. Specifically, sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, inorganic blowing agents such as ammonium nitrite,
Nitroso compounds such as N, N'-dimethyl-N, N'-dinitrosoterephthalamide, N, N'-dinitrosopentamethylenetetramine, diethyl azocarboxylate, azodicarbonamide, azobisisobutyronitrile, azocyclohexyl Azo compounds such as nitrile, azodiaminobenzene and barium azodicarboxylate; sulfonyl hydrazides such as benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, 4,4′-oxybis (benzenesulfonyl hydrazide), and diphenyl sulfone-3,3′-disulfonyl hydrazide; Compound, calcium azide, 4,4'-diphenylsulfonyl azide, p
And azide compounds such as toluenesulfonyl azide. These foaming agents can be used alone or in combination of two or more.

This foaming agent (e) is used in the above (a), (b)
And 3 to 2 parts by weight based on a total of 100 parts by weight of component (c).
5 parts by weight, preferably 4 to 20 parts by weight, more preferably 5 to 15 parts by weight.

Further, if necessary, a foaming aid may be used in combination for the purpose of lowering the decomposition temperature of the foaming agent, accelerating the decomposition, and homogenizing the bubbles. As the foaming auxiliary used,
For example, zinc, calcium, iron, metal compounds such as barium, salicylic acid, phthalic acid, organic acids such as stearic acid,
Alternatively, urea or a derivative thereof may be used.

Further, the foamable composition used in the present invention may further contain various crosslinking agents, crosslinking accelerators,
Foaming aids, weather stabilizers, heat stabilizers, plasticizers, flame retardants,
Additives commonly used in olefin-based thermoplastic elastomer compositions, such as thickeners, lubricants, and colorants, can be added as long as the objects of the present invention are not impaired.

The foam of the present invention may also contain a filler. As the filler used, for example, organic filler materials such as carbon black, nitroso pigment, red iron oxide, phthalocyanine pigment, pulp, fibrous chips, agar, clay, kaolin, talc, silica, diatomaceous earth, aluminum hydroxide, barium sulfate , Calcium sulfate, magnesium carbonate, molybdenum disulfide, zinc oxide, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, mica, bentonite, shirasu balloon, zeolite, silicate clay, cement, fumed silica, glass fiber, glass Examples include inorganic fillers such as spheres, graphite, and alumina.

The foam of the present invention comprises the above-mentioned polyolefin resin (a), ethylene-propylene-non-conjugated diene copolymer (b), low molecular weight polypropylene (c), peroxide (d) and blowing agent (e). ), And other components blended as needed, for example, a foamed composition obtained by crosslinking and foaming a foamable composition containing the ethylene polymer or the like by heating. In the present invention, “crosslinking foaming” means that the polyolefin resin (a) reacts with the peroxide (d) by heating the foamable composition, and the polyolefin resin (a) is decomposed to increase the fluidity. The reaction and the reaction in which the peroxide-crosslinking type ethylene-propylene-nonconjugated diene copolymer (b) and the peroxide (d) crosslink to decrease the fluidity are caused by antagonism, and ethylene-propylene -Means that foam is formed by the foaming agent (e) in parallel with the crosslinking of the non-conjugated diene contained in the non-conjugated diene copolymer (b) to form a foam.

In the production of the foam of the present invention, first, a polyolefin resin (a), an ethylene-propylene-nonconjugated diene copolymer (b) and a low molecular weight polypropylene (c)
Are melt-kneaded to prepare a base material composition. For example, a polyolefin resin (a), an ethylene-propylene-non-conjugated diene copolymer (b) and a low molecular weight polypropylene (c) are temporarily converted into a known type such as V-type Brabender, tumble Brabender, ribbon Brabender, Henschel Brabender, etc. And, if necessary, further kneading using an extruder, a mixing roll, a kneader, a Banbury mixer or the like. At this time, the peroxide (d) and the foaming agent (e) as a crosslinking agent, and other additives may be added and kneaded individually. This kneading is desirably performed at a temperature lower than the decomposition temperature of the foaming agent.

Further, additives such as a foaming aid, a wetting agent, a weather resistance stabilizer, a heat resistance stabilizer, an antioxidant, and a coloring agent, and a filler may be blended at any stage of the melt-kneading. it can.

Next, a peroxide (d) as a crosslinking agent and, if necessary, a crosslinking aid, a vulcanization accelerator and the like are added to the kneaded product obtained by the above-mentioned kneading. Using a known kneading machine such as Brabender, Ribbon Brabender, Henschel Brabender, etc., preferably kneading uniformly at a temperature of 50 ° C. or lower than the decomposition reaction temperature of peroxide (d), and then obtaining the kneading The mixture is kneaded and dispersed with a known kneading machine such as an open-type mixing roll or a non-open-type Banbury mixer, an extruder, a kneader, a continuous mixer, or the like, and the uncrosslinked unfoamed soft resin is dispersed. A molded article can be obtained. This kneading is preferably performed at a temperature lower than the decomposition temperature of the foaming agent (e) and the peroxide (d), preferably at a temperature lower by 20 to 50 ° C. than the one-minute half-life temperature of the peroxide (d). .

Next, the uncrosslinked and unfoamed soft resin molded product obtained by the above process is packed in a molding die formed according to a desired molded product, and is filled at 130 ° C. or more (preferably 140 ° C.). At 230 ° C.), the peroxide (d) and the foaming agent (e) contained in the unfoamed soft resin molded body are thermally decomposed and crosslinked and foamed by hot pressing, whereby the foam of the present invention is formed. Can be manufactured.

The foam of the present invention preferably has a gel fraction of 90 to 99%, particularly preferably 95 to 99%. In the present invention, the gel fraction means that the foam is 14%.
After performing extraction treatment with hot xylene at 0 ° C. for 5 hours, the residue is dried and weighed, and according to the weight before and after the extraction treatment,
It refers to the value obtained according to the following equation. Gel fraction [%] = (W1 × 100 / Wb × W0) × 10
0 [W0: Weight of foam sample before extraction treatment (g) W1: Weight of residue after extraction treatment (g) Wb: Ethylene-propylene-non-conjugated diene copolymer (b) in foam base material In the present invention, the foam having a gel fraction in the above range is excellent in flexibility and heat resistance, and is also excellent in shapeability even under high-temperature heating during molding by heat shaping. It can exhibit excellent mechanical properties that can withstand the tensile load and the load from low pressure to high pressure compression load.

[0038]

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples, the gel fraction [%] and the compression set [%] were determined by the following measuring methods. <Measurement Method> (1) Gel Fraction [%] A foam sample is cut into 1 mm square, and a sample piece of about 0.2 g is precisely weighed (W0 [g]). 140 ° C
After performing an extraction treatment with 500 cc of hot xylene for 5 hours,
The residue is dried and weighed (W1 [g]), and the gel fraction is determined according to the following equation. Gel fraction [%] = (W1 × 100 / Wb × W0) × 1
00 (a) + (b) + (c) = 100 [Wb: parts by weight of ethylene / propylene / non-conjugated diene copolymer (b) in base material of foam]

(2) Compression set [%] JIS K676
According to the measurement method specified in 7, the permanent compression set after compression at 25 ° C. by 50% of the thickness of the test piece is determined.

(Example 1) Propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load) 1.6 g / 10 min] 20 parts by weight, ethylene / propylene / dicyclopentadiene copolymer rubber [EPT:
Ethylene content 38 mol%, diene content (iodine value) 1
2g / 100g, Mooney viscosity ML _{1 + 4} (100 ° C) 40]
An azodicarbonamide [ADC
A; foaming agent] 6 parts by weight, 1 part by weight of 1,3-bis (tert-butylperoxyisopropyl) benzene (peroxide crosslinking agent) and 1 part by weight of zinc oxide were roll-kneaded at 110 ° C. A crosslinked unfoamed composition was prepared.

Next, this uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.065 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 95
%, 50% compressive stress is 0.85 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 7.8%. Then, when the crosslinked foamed sheet was subjected to vacuum forming at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability could be obtained.

Example 2 Propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load) 1.6 g / 10 min] 20 parts by weight, ethylene-propylene-ethylidene norbornene copolymer rubber [EP
T: ethylene content 38 mol%, diene content (iodine value)
12g / 100g, Mooney viscosity ML _{1 + 4} (100 ° C) 6
5] 100 parts by weight of a base material composed of 70 parts by weight and 10 parts by weight of a low-molecular-weight polypropylene [number-average molecular weight (Mn) 3000] are added to azodicarbonamide [A
DCA; foaming agent], 6 parts by weight, 1,3-bis (tert-
Butylperoxyisopropyl) benzene (peroxide crosslinking agent) 1 part by weight and zinc oxide 1 part by weight
And kneaded with a roll to prepare an uncrosslinked unfoamed composition.

Next, the uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.069 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 96.
%, 50% compressive stress is 0.95 kgf / cm ² ,
The 22% 50% compression set at room temperature was 5.8%. Next, when the crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability was obtained.

Example 3 Propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load) 1.6 g / 10 min] 25 parts by weight, ethylene-propylene-dicyclopentadiene copolymer rubber [EPT:
Ethylene content 38 mol%, diene content (iodine value) 12
g / 100 g, Mooney viscosity ML _{1 + 4} (100 ° C.) 40] 5
Base material 1 composed of 5 parts by weight and 20 parts by weight of low molecular weight polypropylene [number average molecular weight (Mn) 3000]
Azodicarbonamide [ADC
A: Blowing agent] 6 parts by weight, 1 part by weight of 1,3-bis (tert-butylperoxyisopropyl) benzene (peroxide crosslinking agent) and 1 part by weight of zinc oxide are roll-kneaded at 110 ° C., and are not crosslinked. A foam composition was prepared.

Next, the uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.063 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 96.
%, 50% compressive stress is 0.65 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 6.9%. Next, when the crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability was obtained.

Example 4 A propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load) 1.6 g / 10 min] 20 parts by weight, ethylene-propylene-dicyclopentadiene copolymer rubber [EPT:
Ethylene content 38 mol%, diene content (iodine value) 12
g / 100 g, Mooney viscosity ML _{1 + 4} (100 ° C.) 80] 6
Substrate 1 composed of 0 parts by weight and 10 parts by weight of low molecular weight polypropylene [number average molecular weight (Mn) 3000]
Azodicarbonamide [ADC
A; foaming agent] 6 parts by weight, 1 part by weight of 1,3-bis (tert-butylperoxyisopropyl) benzene (peroxide crosslinking agent) and 1 part by weight of zinc oxide were roll-kneaded at 110 ° C. A crosslinked unfoamed composition was prepared.

Next, this uncrosslinked unfoamed composition was placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.069 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 98.
%, 50% compressive stress is 0.95 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 5.3%. Next, when the crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability was obtained.

Example 5 1-butene polymer [PB; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load: 1.8 g / 10 min] 20 parts by weight, ethylene-propylene-dicyclopentadiene copolymer rubber [EPT;
Ethylene content 38 mol%, diene content (iodine value) 12
g / 100 g, Mooney viscosity ML _{1 + 4} (100 ° C.) 80] 6
Substrate 1 composed of 0 parts by weight and 10 parts by weight of low molecular weight polypropylene [number average molecular weight (Mn) 3000]
Azodicarbonamide [ADC
A; foaming agent] 6 parts by weight, 1 part by weight of 1,3-bis (tert-butylperoxyisopropyl) benzene (peroxide crosslinking agent) and 1 part by weight of zinc oxide were roll-kneaded at 110 ° C. A crosslinked unfoamed composition was prepared.

Next, this uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.069 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 97
%, 50% compressive stress is 0.90 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 6.1%. Next, when the crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability was obtained.

Example 6 4-Methyl-1-pentene polymer [PMP; MFR (ASTM D1238, 230)
° C, 2.16 kg load) 5 g / 10 min] 20 parts by weight, ethylene-propylene-dicyclopentadiene copolymer rubber [EPT; ethylene content 38 mol%, diene content (iodine value) 12 g / 100 g, Mooney viscosity ML _{1 +4} (100
80 ° C.) 80 parts by weight, and 6 parts by weight of azodicarbonamide [ADCA; foaming agent] based on 100 parts by weight of a base material composed of 60 parts by weight and 10 parts by weight of low molecular weight polypropylene [number average molecular weight (Mn) 3000] , 1,3-bis (te
1 part by weight of rt-butylperoxyisopropyl) benzene (peroxide crosslinking agent) and 1 part by weight of zinc oxide
Roll kneading was performed at 10 ° C. to prepare an uncrosslinked unfoamed composition.

Next, this uncrosslinked unfoamed composition was placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to obtain a crosslinked foamed sheet having a density of 0.069 g / cm ³ and a thickness of 5 mm. Was. This crosslinked foamed sheet has a gel fraction of 98.
%, 50% compressive stress is 0.95 kgf / cm ² ,
The 22% 50% compression set at room temperature was 5.8%. Next, when the crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., a flexible molded article having a uniform foam thickness and excellent shapeability was obtained.

Comparative Example 1 Propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load: 1.6 g / 10 min] 22.2 parts by weight, and ethylene-propylene-ethylidene norbornene copolymer rubber [EPT: ethylene content 38 mol%, diene content (iodine value) 12 g / 100 g, Mooney viscosity ML _{1+ 4} (100
° C) 65] 6 parts by weight of azodicarbonamide (ADCA; blowing agent), 100 parts by weight of a base material composed of 77.7 parts by weight, 1,3-bis (tert-butylperoxyisopropyl) benzene ( Roll kneading of 1 part by weight of a peroxide crosslinking agent) and 1 part by weight of zinc oxide was attempted at 110 ° C., but only an uncrosslinked unfoamed composition having an inhomogeneous kneading state was obtained.

Next, this heterogeneous uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to form a crosslinked foamed foam having a density of 0.064 g / cm ³ and a thickness of 5 mm. Although the sheet was obtained, the foam was in a state of being cracked or having various sizes of pores inside the foam. This crosslinked foamed sheet has a gel fraction of 8
7%, 50% compressive stress is 0.9 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 5.2%. Next, when this crosslinked foamed sheet was subjected to vacuum forming at a foam surface temperature of 170 ° C., the thickness of the foam of the formed product was not uniform, and an uneven molded product was obtained particularly at a deep drawn shape.

Comparative Example 2 Propylene polymer [PP; M
FR (ASTM D1238, 230 ° C, 2.16 kg
Load: 1.6 g / 10 min] 22.2 parts by weight, and ethylene-propylene-dicyclopentadiene copolymer rubber [EPT: ethylene content 38 mol%, diene content (iodine value) 12 g / 100 g, Mooney viscosity ML _{1 +4} (100
80] 6 parts by weight of azodicarbonamide (ADCA; blowing agent) and 1,3-bis (tert-butylperoxyisopropyl) benzene (100 parts by weight of base material composed of 77.7 parts by weight) Roll kneading of 1 part by weight of a peroxide crosslinking agent) and 1 part by weight of zinc oxide was attempted at 110 ° C., but only an uncrosslinked unfoamed composition having an inhomogeneous kneading state was obtained.

Next, this heterogeneous uncrosslinked unfoamed composition is placed in a mold having a thickness of 2 mm and press-foamed at 170 ° C. to form a crosslinked foamed foam having a density of 0.069 g / cm ³ and a thickness of 5 mm. Although the sheet was obtained, the foam was in a state of being cracked or having various sizes of pores inside the foam. This crosslinked foamed sheet has a gel fraction of 6
7%, 50% compressive stress is 0.8 kgf / cm ² ,
The 22-hour 50% compression set at room temperature was 7.3%. Next, when this crosslinked foamed sheet was subjected to vacuum molding at a foam surface temperature of 170 ° C., the foam thickness of the molded article was considerably uneven, and an uneven molded article was obtained particularly at a deep drawn shape. . The above results are summarized in Table 1.

[0057]

[Table 1]

Note) Foaming state ：: A homogeneous foam is obtained. X: A heterogeneous foam is obtained. Molding state 成形: A molded article is obtained in a more uniform state. Part with extremely uneven thickness)

[0059]

EFFECT OF THE INVENTION The olefin foam of the present invention has excellent flexibility and recyclability, and has excellent moldability and tensile strength even under high-temperature heating during molding by heating. Excellent mechanical properties capable of withstanding loads and compressive loads from low pressure to high pressure can be exhibited. The olefin foam of the present invention contains a high Mooney viscosity ethylene-propylene-non-conjugated diene copolymer, and contains a high melting point peroxide-decomposed polyolefin resin in order to improve heat resistance. Since it is contained in an amount, uniform physical properties can be obtained. Therefore, the foam of the present invention has excellent recyclability, excellent mechanical properties against tensile elongation and compression, and is suitable as a material for members required to withstand the severe molding conditions imposed during heat forming. In particular, it is suitable as a foam material for lining interior materials such as instrument panels, door panels, and consoles of automobiles.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Muneyasu Yamaoka, 3 Chizusa Beach, Ichihara-shi, Chiba Mitsui Chemicals Co., Ltd. (72) Inventor Akira 3 Chigusa Coast, Ichihara-shi, Chiba 3 Mitsui Chemicals, Inc. (72) Inventor Koichi Kusakawa 1170-1 Ako, Komagane-shi, Nagano Prefecture, Japan Incorporated company (72) Inventor Shigeki Ichimura 1170-1, Ako, Komagane-shi, Nagano prefecture, Japan Incorporated company (72) Inventor Yonezawa Takashi 1170-1 Ako, Komagane-shi, Nagano Prefecture Japan-originated stock company (72) Inventor Junzo Ukai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hideo Nishimura Toyota Town, Toyota City, Aichi Prefecture No. 1 Toyota Motor Corporation F term (reference) 4F074 AA16 AA24 AA25 AA26 AA98 AB01 AB03 AB05 BA13 BB02 CA24 CC06Y DA04 DA08 DA20 DA35 DA54 DA55

Claims (1)

[Claims] (1) a melt flow rate of 0.1 to 80;
g / 10 min peroxide decomposable polyolefin resin 5
90 parts by weight, (b) The diene content is 10 to 25 g / 100 in iodine value.
g, and Mooney viscosity ML _{1 + 4} (100 ° C.) is 10 to 300.
9 to 94 parts by weight of a peroxide crosslinked ethylene-propylene-nonconjugated diene copolymer of (c) having a number average molecular weight of 1,000 to 15,000 and a melting point of 1
1 to 40 parts by weight of low molecular weight polypropylene at 35 to 145 ° C (where the total of (a) + (b) + (c) is 100 parts by weight) (d) Peroxide 0.5 to 2.5 Part by weight (e) An olefin foam obtained by heating a foamable composition containing 3 to 25 parts by weight of a foaming agent.