JPH05194777A - Silicone-modified polyolefin resin composition for foaming and production of resin foam - Google Patents

Abstract

PURPOSE:To produce the title compsn. which gives a foam having cells with diameters more uniform than those of the conventional polyolefin resin foam by mixing a polyolefin resin, an organopolysiloxane, and an org. peroxide under heating and mixing the resulting silicone-modified polyolefin resin with a blow ing agent. CONSTITUTION:100 pts.wt. polyolefin resin, 0.01-10 pts.wt. organopolysiloxane, and 0. 005-1 pt.wt. org. peroxide are mixed under heating to give a silicone modified polyolefin resin. 100 pts.wt. the modified polyolefin resin is mixed with 1-30 pts.wt. blowing agent to give the title compsn., which is formed into a desired shape below the decomposition temp. of the blowing agent and foamed by heating to 110-300 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a silicone-modified olefin polymer foam and a method for producing a resin foam. More specifically, the present invention relates to a resin composition for a resin foam having a uniform cell diameter and a method for producing the resin foam.

[0002]

2. Description of the Related Art There are many foams of olefinic polymers containing silicone compounds and resin compositions for the foams, which have been invented and filed by the inventors of the present invention (for example, JP-A-60-49657, JP-A-60-124632, JP-A-62-89738 and JP-A-62.
-89739, 62-89741, 62-89.
No. 742, No. 63-113034, No. 63-1130
35, 63-126723, JP-A-2-1076.
No. 43, No. 2-107644, No. 3-21640,
No. 3-21641, No. 3-21642, and No. 3-12
No. 4742, No. 3-139536, No. 3-26902
No. 6, No. 3-269027, No. 3-287635,
3-287636, etc.). However, foams made from these conventional olefin-based polymers lack somewhat uniform cell size, and are not satisfactory for special applications such as high-performance filters, high-performance cushioning materials, and high-grade articles. ..

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a resin composition for a foam having a more uniform cell diameter as compared with a foam made of a conventional olefin polymer, and a method for producing the resin foam. Is an issue.

[0004]

In order to develop a foam composition having the above preferable properties, the present inventors have
When an experiment was conducted by blending various polymers with an olefin resin, it was found that a resin composition blended with a specific polymer gives a foam having a uniform cell diameter, thus completing the present invention.

That is, the present invention relates to an olefin resin 1
Silicon modified olefin polymer 100 obtained by heating and kneading 00 parts by weight, 0.01 to 10 parts by weight of organopolysiloxane and 0.005 to 1 part by weight of organic peroxide.
The present invention relates to a resin composition for silicone-modified olefin polymer foam, which comprises 1 part by weight and 1 to 30 parts by weight of a foaming agent.

Further, according to the present invention, the above resin composition is processed into a predetermined shape at a temperature not higher than the decomposition temperature of the compounded foaming agent,
Next, it relates to a method for producing a resin foam, which comprises heating it to 110 to 300 ° C.

In the present invention, the olefin resin means
Homopolymer of ethylene, copolymer of ethylene and other α-olefin, copolymer of ethylene and vinyl acetate or ethyl acrylate, homopolymer of α-olefin other than ethylene, copolymerizable with α-olefin It means a copolymer with a vinyl monomer.

Examples of such olefin resins include high-pressure low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, high-density polyethylene, medium-density polyethylene, and vapor-phase straight-chain resin. Low density polyethylene, gas phase ultra low density polyethylene, ethylene-propylene rubber, ethylene-propylene-diene rubber, isobutylene-isoprene rubber, polypropylene,
There are polybutene-1 and the like, and these may be used alone or in combination of two or more kinds.

In the present invention, the organopolysiloxane means the following formula I: (In the formula, R ¹ represents an aliphatic unsaturated group, R ² represents an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group, and a
And b have the following conditions: 0 ≦ a <1, 0.5 <b <3, 1
<Are those represented by a numeric value that satisfies a + b <3), in this, a vinyl group as ^a group R, an allyl group, acryl group, methacryl group or the like, and examples of R ² is a methyl group, Alkyl group such as ethyl group, propyl group, phenyl group, aryl group such as tolyl group, cycloalkyl group such as cyclohexyl group, cyclobutyl group and hydrogen atom partially bonded to carbon atoms of these hydrocarbon groups, a halogen atom, Examples thereof include a group substituted with a cyano group, a mercapto group, and the like, but these may be the same kind or different kinds of combinations.

In the above formula I, a is 0 or greater than 0 and less than 1. This range is because when a is 1 or more, the foam produced by the present invention becomes too hard. a is preferably 0.0004 to 0.06.

In the above formula I, b is greater than 0.5 and less than 3. If this range is 0.5 or less, it is difficult to knead the composition of the present invention and the processability is poor, and if it is 3 or more, the foam produced by the present invention becomes too hard, which is not desirable. b is preferably 1-2.

The molecular structure of the organopolysiloxane in the present invention may be linear, branched, cyclic, reticulated, three-dimensional reticulated or the like, as long as it is represented by the above formula I.

Examples of such organopolysiloxanes include so-called silicone gum stock, which is commercially available as a tear strength improver for silicone rubber. Further, the linear organopolysiloxane used in the present invention has a general formula: (In the formula, R represents an unsubstituted or substituted monovalent hydrocarbon group,
n represents a number of 10 or more), and there is one generally called silicone oil.

R in the above formula is a group selected from an alkyl group, an aryl group and a hydrogen atom, and is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group,
Typical examples are i-butyl group, t-butyl group, phenyl group and hydrogen atom. All R's in the molecule may be the same, some R's may be different groups, and some R's may be vinyl groups or hydroxyl groups.

N is 10 or more, and 100 to 10
00 is preferred. When n is less than 10, kneading with the olefin resin becomes difficult.

The organopolysiloxane polymer represented by the above formula I used in the present invention has a viscosity at 23 ° C. of 10 CS or more, preferably 10 ³ to 10 ⁶ CS. When the viscosity is lower than 10 CS, heat kneading is difficult, and the organopolysiloxane polymer may exude from the surface of the foam.

Examples of the functional group-containing organopolysiloxane include vinylmethyl-dimethylpolysiloxane and vinylmethyl-phenylmethyl-dimethylpolysiloxane.

The organic peroxide which can be used in the present invention preferably has a decomposition temperature of 100 to 220 ° C. with a half-life of 10 minutes, that is, a 10 minute half-life temperature (Tp) of 100 to 220 ° C. Examples thereof include the following (however, the temperature in parentheses is the decomposition temperature (° C)): succinic acid peroxide (110), benzoyl peroxide (110), t-butylperoxy-2-ethylhexanoate. (113), p-chlorobenzoyl peroxide (115), t-butylperoxyisobutyrate (115), t-butylperoxyisopropyl carbonate (135), t-butylperoxylaurate (140), 2,5-dimethyl-. Two
5-di (benzoylperoxy) hexane (140),
t-butyl peroxyacetate (140), di-t-
Butyldiperoxyphthalate (140), t-butylperoxymaleic acid (140), cyclohexanone peroxide (145), t-butylperoxybenzoate (145), dicumyl peroxide (150),
2,5-Dimethyl-2,5-di (t-butylperoxy) hexane (155), t-butylcumyl peroxide (155), t-butyl hydroperoxide (15)
8), di-t-butyl peroxide (160), 2,5
-Dimethyl-2,5-di (t-butylperoxy) hexyne-3 (170), di-isopropylbenzene hydroperoxide (170), p-menthane hydroperoxide (180), 2,5-dimethylhexane-2,5 −
Dihydroperoxide (213).

The foaming agent used in the present invention has a foaming temperature of 15 from the melting point of the olefin resin used.
It is preferably higher than ℃, and therefore selected according to the olefin resin. Typical examples are azobisisobutyronitrile, diazocarbonamide, p-toluenesulfonylhydrazide, 4,4′-oxybis (benzenesulfonyl). Hydrazide), n-heptane, n-octane, n-nonane, n-decane and the like.
In addition, the foaming agent of the present invention also includes a foaming temperature adjusted within the above range by using an accelerator or an auxiliary agent together.

In the present invention, the blending amounts of the organopolysiloxane and the organic peroxide are 0.01 to 10 parts by weight and 0.005 to 1 part by weight, respectively, relative to 100 parts by weight of the olefin resin. This is the lower limit for both components (ie 0.01 parts by weight of organopolysiloxane,
If the amount of the organic peroxide is less than 0.005 parts by weight, the bubbles of the resulting foam may be connected to each other to increase the bubble diameter, and it is difficult to obtain a uniform bubble diameter. Further, the upper limit (that is, the organopolysiloxane) is not obtained. Is more than 10 parts by weight and the organic peroxide is more than 1 part by weight), the expansion ratio is not increased, which is not desirable.

The blending amount of the foaming agent in the present invention is
The amount is 1 to 30 parts by weight based on 100 parts by weight of a silicone-modified olefin polymer obtained by kneading an olefin resin, an organopolysiloxane and an organic peroxide with heating. This is because if the amount is less than 1 part by weight, the effect of foaming is scarce, and if the amount is more than 30 parts by weight, the amount of the decomposed product of the foaming agent that scatters into the atmosphere at the time of foaming is increased and the foaming efficiency is poor.

If desired, the resin composition of the present invention may further contain other additives such as an oxidation stabilizer, an ultraviolet stabilizer, an inorganic filler, a pigment, a flame retardant, and rubbers. These are preferably added to the olefin resin in advance.

The silicone-modified olefin polymer according to the present invention is obtained by heating and kneading a composition comprising an olefin resin, an organopolysiloxane and an organic peroxide, and this heating and kneading is 10% higher than the melting point of the olefin resin. It is desirable to carry out at a temperature higher than ℃.

Further, the resin composition for a silicone-modified olefin polymer foam of the present invention contains a predetermined amount of a silicone-modified olefin polymer and a foaming agent at a temperature higher than the melting point of the olefin resin by at least 10 ° C. It is obtained by heating and kneading at a temperature below the foaming temperature.

In the resin foam of the present invention, first, the above resin composition is processed into a predetermined shape at a temperature not higher than the decomposition temperature of the compounded foaming agent, and then at a temperature not lower than the temperature required for foaming, that is, 110.
By heating to ˜300 ° C., it is produced as having a uniform bubble diameter. The heating at this time may be performed under normal pressure or under pressure. Further, the foam in the present invention is not particularly limited, but means, for example, a filtering material, a door material for automobiles, a cushioning material for building materials, a vibration damping material, a cushioning material and the like.

[0026]

EXAMPLES Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples, and those embodying the technical idea of the present invention are within the scope of the present invention. Contained within. In the following examples, parts mean parts by weight.

Example 1 100 parts of ethylene-propylene random copolymer (manufactured by Tonen Kagaku) having an ethylene content of 4% by weight as an olefin resin and a melt flow index of 15 g / 10 min, and a methylvinylsiloxane content of 0 as an organopolysiloxane. Silicone gum stock having a plasticity of 80 mol% at 70 ° C. (trade name RZ7601, manufactured by Nippon Unicar) 1
Parts and 0.04 parts of organic peroxide 1,3-di (t-butylperoxyisopropyl) benzene (trade name Perbutyl P, manufactured by NOF CORPORATION) with a Banbury mixer.
The mixture was kneaded at 20 ° C. for 20 minutes. This kneaded product was named "SG-A".

SG-A 100 parts, foaming agent azodicarbonamide having a foaming temperature of 204 ° C. (trade name Celmic C-2,
8 parts of Sankyo Kasei Co., Ltd. and 0.1 parts of an antioxidant (trade name Irganox 1010, manufactured by Ciba-Geigy) were kneaded with a kneader at 160 ° C. for 10 minutes, and then compression molded at 160 ° C. to a thickness of 1 mm. It was a sheet. This sheet was placed on a polyester sheet and placed in an oven at 200 ° C., whereupon it foamed uniformly in 9 minutes. When this foam was taken out and allowed to cool to room temperature, a foam having a uniform cell diameter of 10 mm and an average cell diameter of 0.4 mm was obtained.

Comparative Example Example 1 except that the unmodified ethylene-propylene random copolymer described in Example 1 was used instead of SG-A.
The same operation as above was repeated to obtain a sheet. When this sheet was placed on a polyester sheet and put in an oven at 200 ° C., it foamed in 9 minutes, but a foam having non-uniform thickness and non-uniform bubbles such as partial collapse of bubbles was obtained. It was

Example 2 Linear low-density polyethylene (trade name NUCG-538)
1, 100 parts of Nippon Unicar), 2 parts of silicone gum stock (trade name RZ7601, manufactured by Nippon Unicar) and 1,3-di (t-butylperoxyisopropyl) benzene (trade name of Perbutyl P, manufactured by NOF CORPORATION) 0.15 The parts were kneaded with a Banbury mixer at 160 ° C. for 20 minutes. This kneaded product was named "SG-B".

SG-B 100 parts, foaming agent azodicarbonamide having a foaming temperature of 204 ° C. (trade name Celmic C-2,
8 parts of Sankyo Kasei Co., Ltd. and 0.1 parts of an antioxidant (trade name Irganox 1010, manufactured by Ciba-Geigy) were kneaded with a kneader at 160 ° C. for 10 minutes, and then compression molded at 160 ° C. to a thickness of 1 mm. And the sheet. This sheet was placed on a polyester sheet and placed in an oven at 200 ° C., whereupon it foamed uniformly in 8 minutes. When this foam was taken out and allowed to cool to room temperature, a foam having a uniform cell diameter of 10 mm in thickness and an average cell diameter of 0.25 mm was obtained.

Example 3 Ethylene-vinyl acetate copolymer (trade name: DQDJ-38
68, manufactured by Nippon Unicar) 100 parts, silicone gum stock (trade name RZ7601, manufactured by Nippon Unicar) 2 parts and 1,3-di (t-butylperoxyisopropyl) benzene (trade name Perbutyl P, manufactured by NOF CORPORATION) 0.15 The parts were kneaded with a Banbury mixer at 160 ° C. for 20 minutes. This kneaded product was named "SG-C".

Foaming agent azodicarbonamide (trade name: Celmic C-2, product of SG-C 100 parts, foaming temperature 204 ° C.)
8 parts of Sankyo Kasei Co., Ltd. and 0.1 parts of an antioxidant (trade name Irganox 1010, manufactured by Ciba-Geigy) were kneaded with a kneader at 160 ° C. for 10 minutes, and then compression molded at 160 ° C. to a thickness of 1 mm. It was a sheet. This sheet was placed on a polyester sheet and placed in an oven at 200 ° C., whereupon it foamed uniformly in 8 minutes. When this foam was taken out and allowed to cool to room temperature, a foam having a uniform cell diameter of 10 mm in thickness and an average cell diameter of 0.3 mm was obtained.

[0034]

As described in detail above, the resin composition for a silicone-modified olefin polymer foam of the present invention provides a resin foam having a uniform cell diameter. Such a resin foam is useful as a filter material because it allows a uniform passage speed, a uniform pressure, only a substance having a specific diameter or less in the filtration of gas, liquid, organic compound, inorganic compound and the like. In addition, since it has uniform performance in terms of compressibility, impact resilience, etc., it is highly useful as a cushioning material, and it can be made into a fashionable and high-grade product with a beautiful appearance. As described above, the present invention makes it possible to provide a high-performance filter, a high-performance cushioning material, a vibration-proof material, a cushioning material, an automobile door material, and the like.

Claims (2)

[Claims] 1. A silicone-modified olefin-based polymer obtained by heating and kneading 100 parts by weight of an olefin resin, 0.01 to 10 parts by weight of organopolysiloxane and 0.005 to 1 part by weight of an organic peroxide, and A resin composition for a silicone-modified olefin polymer foam, which comprises 1 to 30 parts by weight of a foaming agent. 2. A resin foam, which comprises processing the resin composition according to claim 1 into a predetermined shape at a temperature not higher than the decomposition temperature of the compounded foaming agent and then heating it to 110 to 300 ° C. Production method.