JPH04342743A - Composition for open-cell type propylene-based resin foam - Google Patents

Abstract

PURPOSE:To obtain a composition for open-cell type propylene-based resin foam suitable for building material, agricultural material, filter, etc., being excellent in heat resistance, mechanical characteristics, chemical resistance, etc., and uniform foam diameter. CONSTITUTION:(A) 100 pts.wt. polypropylene-based resin is blended with (B) 0.01-10 pts.wt. lower alkenyl group-containing organopolysiloxane, (C) 1-30 pts.wt. blowing agent (e.g. azobisisobutyronitrile) having 100-200 deg.C foaming temperature (Tf) and (D) 0.2-10 pts.wt. organic peroxide (e.g. succinic acid peroxide) having 110-220 deg.C 10 minutes half-life period temperature (Tp) and satisfying -10 deg.C<=Tp-Tf<=50 deg.C, molded into a given shape at <= the decomposition temperature of the blowing agent and <= the decomposition temperature of the organic peroxide and heated to 130-300 deg.C.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for open-cell propylene resin foam. More specifically, the present invention relates to a resin composition from which an open-cell propylene resin foam having excellent heat resistance, mechanical properties, chemical resistance, etc. It is used in heat insulating materials, automobile interior materials, various mat materials, etc., and is particularly suitable as various filter materials.

0002

[Prior Art] Propylene resin is a highly crystalline resin with stereoregular coordination, so it has a melting point about 30 to 50°C higher than ethylene resin, and has excellent heat resistance and mechanical strength. Therefore, foams made from this material have been proposed. Propylene resins have a higher melting point and lower melt viscosity than ethylene resins, and the viscosity changes rapidly near the melting point, so the temperature range suitable for extrusion foaming is extremely narrow. Therefore, it is difficult to uniformly knead a blowing agent into a propylene resin, and even if it were possible to knead it, only a blowing agent with a high decomposition temperature can be used, and the range of selection of blowing agents is narrow. In addition, in order to obtain an appropriate melt viscosity for foaming, crosslinking with an organic peroxide may be considered as a diversion from polyethylene foaming technology, but due to the molecular structure of polypropylene, it contains tertiary carbon, so the crosslinking reaction The decomposition reaction takes priority and no effective effect can be obtained unless a crosslinking aid is used.

In order to solve these problems, the melting point of the polymer is lowered by copolymerizing propylene with other monomers, so that the melt viscosity is relatively high over a wide temperature range and the change in melt viscosity is small. It is proposed that
1460 etc.). There is also a proposal to incorporate a styrene-isoprene block copolymer in order to prevent the melt viscosity from decreasing (Japanese Patent Publication No. 60-39697). Furthermore, a method has been proposed in which the melt viscosity is made relatively high by modifying a propylene resin with an alkoxy group-containing vinylsilane and water-crosslinking it (Japanese Patent Publication No. 18933/1983). Foams made of propylene resin have come to be industrially produced by these methods, but all of them have a closed cell structure, and open cell foams have never been proposed.

0004

[Problems to be Solved by the Invention] The present invention provides that conventional propylene resin foams have a closed cell structure and are inferior in air permeability, softness, flexibility, etc., and in particular, have no air permeability at all. Since it cannot be used as a filtering material, in order to solve these problems, it is an object of the present invention to propose an open-cell propylene-based resin foam.

[0005]

[Means for solving the problem] As mentioned above, propylene resin has a high melting point, and the viscosity decreases rapidly above the melting temperature of the crystals. Providing an appropriate melt viscosity is an important technical point in making a foam, and creating an open-cell foam requires special means.

[0006] The present inventors have applied for numerous patents regarding the technology for obtaining open-cell foams using ethylene resin as a material (Japanese Patent Publication No. 49657/1983, Japanese Patent Application Laid-open No. 60-49657,
No. 0-124632, No. 62-89738, No. 62-
No. 89739, No. 62-89741, No. 62-897
No. 42, No. 63-113034, No. 63-11303
No. 5, No. 63-126733, patent application No. 63-2606
No. 20, No. 63-260621, Patent Application No. 1-1546
No. 36, No. 1-154637, No. 1-264419, No. 1-276149, etc.). The present invention has been completed by developing these techniques and applying them to propylene-based resins.

That is, the present invention comprises: (1) a) 100 parts by weight of a propylene resin; b) 0.01 to 0.01 parts by weight of a lower alkenyl group-containing organopolysiloxane;
c) 1 to 30 parts by weight of a blowing agent having a foaming temperature (Tf) in the range of 100 to 200°C, and d) 0 organic peroxide having a 10 minute half-life temperature (Tp) of 110 to 220°C. .2 to 10 parts by weight (however, -10℃≦T
p-Tf≦50°C); (2) The composition for open-cell propylene resin foam of (1) above is heated below the decomposition temperature of the blowing agent. and processed into a predetermined shape at a temperature below the decomposition temperature of the organic peroxide, and
A method for producing an open-cell propylene resin foam characterized by heating to 300°C; (3) An open-cell propylene resin foam produced by the production method in (2) above.

In the present invention, the propylene resin is a polymer whose main component is propylene, including propylene homopolymer, propylene and other α-olefins (ethylene,
Butene-1, 4-methyl-pentene-1, hexene-1
, octene-1, etc.), and has an MFR (metre flow rate) of 0.1 to 2.
0 (g/min 230°C), preferably 0.2 to 10. If it is less than 0.1, it will be difficult to knead with a foaming agent and the extrusion processability will be poor, and if it is more than 20, the melt viscosity will decrease and foaming will become difficult. Specific examples include polypropylene, propylene-ethylene block or random copolymers, propylene-butene-1 block or random copolymers propylene-ethylene-butene-1, random or block copolymers, and the like.

In the present invention, the lower alkenyl group-containing organopolysiloxane has the general formula

[Formula 1] (wherein, R1 is an alkenyl group, R2 is an unsubstituted or substituted monovalent hydrocarbon group not containing an alkenyl group, 0<a<1
, 0.5<b<3, 1<a+b<3). Specific examples of R1 are vinyl, allyl, isopropenyl, acrylic, methacryl, etc., and R2 is methyl, ethyl, propyl, butyl, pentyl, hexyl,
aliphatic hydrocarbon groups such as phenyl, tolyl, xylyl,
Represents unsubstituted or substituted monovalent hydrocarbon groups that do not contain alkenyl groups, such as aromatic hydrocarbon groups such as cumenyl, mesityl, benzyl, phenethyl, and styryl, and alicyclic hydrocarbon groups such as cyclohexyl and cyclobutyl groups. may be a combination of the same or different types thereof. Also, a is 0
It needs to be larger and less than 1, preferably from 0.0004 to 0.06. If a is 0, reaction with the ethylene resin will not occur, which is undesirable;
If it is more than that, the foam produced from the composition of the present invention will become too hard, which is not desirable. b is greater than 0.5 and 3
It needs to be less than 1, preferably 1 to 2. If b is less than 0.5, it will be difficult to knead the composition of the present invention and the processability will be reduced, and if b is greater than 3, the foam produced from the composition of the present invention will become too hard, which is undesirable. In the present invention, the amount of the lower alkenyl group-containing organopolysiloxane used is 0.01 to 10 parts by weight, and 0.01 to 10 parts by weight.
If it is less than 0.01 parts by weight, it will not form an open foam, and even if it is more than 10 parts by weight, the effect of forming an open foam will reach a saturation point, causing an undesirable oozing phenomenon. The molecular structure of the organopolysiloxane of the present invention may be linear, branched, cyclic, network, three-dimensional network, etc., as long as it falls within the range of formula (A). Specific examples include vinylmethyl-dimethylpolysiloxane and vinylmethyl-phenylmethyl-dimethylpolysiloxane.

The foaming agent used in the present invention has a foaming temperature of 100°C to 220°C, preferably a decomposition temperature higher than the crystal melting point of the propylene resin used, and is used in combination with an accelerator or auxiliary agent. This also includes those whose decomposition temperature is adjusted within this range. As an example,
These include: azobisisobutyronitrile,
Diazocarbonamide, p-toluenesulfonylhydrazide, 4,4'-oxybis(benzenesulfonylhydrazide), n-heptane, n-octane, n-nonane,
n-decane. The amount of blowing agent required is 1 to 30 parts by weight. If it is less than 1 part by weight, there is almost no foaming effect, and if it is more than 30 parts, the amount of foaming agent decomposition products that wastefully escape into the atmosphere during foaming increases, resulting in poor efficiency.

The organic peroxide used in the present invention preferably has a decomposition temperature of 110 to 220°C with a half-life of 10 minutes, that is, a half-life of 110 to 220°C in 10 minutes. Examples include: However, the value 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-2,5-di(benzoylperoxy)hexane (140), t-butylperoxyacetate (140), di-t -butyl diperoxyphthalate (140), t-butylperoxymaleic acid (140), cyclohexanone peroxide (14)
5), t-butyl peroxybenzoate (145),
Dicumyl peroxide (150), 2,5-dimethyl-
2,5-di(t-butylperoxy)hexane (155
), t-butylcumyl peroxide (155), t-butyl hydroperoxide (158), 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).

In the present invention, the amount of organic peroxide is 0.2
~10 parts by weight are required. If it is less than 0.2 parts by weight, the viscosity of the resin will hardly increase when the composition is heated, and the resin layer will become flat. Even if the amount is more than 10 parts by weight, the increase in crosslinking efficiency is small. Next, in the present invention, 1 of the organic peroxide
When the 0 minute half-life temperature is Tp and the foaming temperature of the blowing agent is Tf, the organic peroxide and the blowing agent should be selected and combined so as to satisfy the following formula -10℃≦Tp-Tf≦50℃. is necessary. That is, by using such a combination, by heating the composition and then cooling it, a foam with open cells or open cells containing some closed cells can be obtained.

In the present invention, an ethylene resin such as polyethylene, an oxidation stabilizer, an ultraviolet stabilizer, an inorganic filler, a pigment, a flame retardant, a rubber, etc. can be added to the composition as necessary. The temperature at which the composition of the present invention is heated is:
The temperature is above the temperature necessary for foaming and crosslinking to occur, specifically between 130 and 300°C. In the present invention, the decomposition temperature of the organic peroxide is the half-life of the pure product.
Since the temperature is shown at 0 minutes, crosslinking proceeds even below this temperature. Depending on the purpose, heating can be carried out either under normal pressure or under increased pressure.

In order to produce the open-cell propylene resin foam of the present invention, each component is mixed and kneaded at a temperature below the decomposition temperature of the blowing agent or chemical blowing agent, and the kneaded product is formed into a predetermined shape, for example. , sheets, rods, balls, etc. are made, with or without a mold, at a temperature higher than the decomposition temperature of the blowing agent or chemical foaming agent and satisfying -10℃≦Tp-Tf≦50℃. It can be obtained by heating (or pressurizing) at a temperature of Examples of the present invention are shown below.

[0015]

【Example】

Example 1 Impact-resistant polypropylene J-409 (manufactured by Tonen Chemical) 20
kg, azodicarbonamide foaming agent “Celmic C-
2" (foaming temperature 204°C: manufactured by Sankyo Kasei) 2 kg, organic peroxide "Parkadox 14" (decomposition temperature 158°C: manufactured by Kayaku Nury) 40 g, antioxidant "Irganox 1"
010'' (manufactured by Ciba Geigy) 10 g, silicone gum stock with a viscosity of 300,000 CP at 23°C and a methyl vinyl silicone content of 1.0% (manufactured by Nippon Unicar)
600 g was kneaded at 160° C. for 10 minutes using a DS20-40MWA-H type kneader manufactured by Moriyama Seisakusho. The rotation speed of the blade was 45 rpm. This kneaded material was pelletized. This pellet was compressed at 150℃ to a thickness of 1m.
It was made into a sheet of m. Pressure and time are each 100kg/
cm2 for 5 minutes. When this sheet was placed on a polyester sheet and placed in an oven at 200°C, it foamed uniformly in 9 minutes. When this foam was taken out and allowed to cool to room temperature, it had a thickness of 10 mm and an average cell diameter of 0.
．． A 5 mm foam was obtained. The density of the foam is 0.07
It was 3g/cm3. After this foam was immersed in warm water at 90° C. for 10 minutes, the thickness was measured and found to be 10 mm. In addition, when the foam was repeatedly compressed and relaxed in water at 23°C to force it to absorb water, the result was 8 per cm3.
．． 5g of water was absorbed.

Comparative Example 1 A sheet was obtained in the same manner as in Example 1 using dithylpolysiloxane (manufactured by Nippon Unicar) having a viscosity of 300,000 CP at 23° C. instead of the silicone gum stock. Place this sheet on top of the polyester sheet and
When it was placed in an oven at ℃, it foamed in 9 minutes. When this foam was taken out and allowed to cool to room temperature, the thickness was 1.
Although the foam had a diameter of 0 mm, it was a foam with rough cells having an average major axis of 5 mm and an average minor axis of 1 mm.

Comparative Example 2 A sheet was obtained in the same manner as in Example 1 without using a crosslinking agent. Place this sheet on top of the polyester sheet and
When it was placed in an oven at ℃, it foamed in 9 minutes. When this foam was taken out and allowed to cool to room temperature, the thickness was 1.
Although the foam had a diameter of 0 mm, it was a foam with rough cells having an average major axis of 5 mm and an average minor axis of 1 mm.

Example 2 Impact-resistant polypropylene J-409 (manufactured by Tonen Chemical Co., Ltd.) 18
kg, low density polyethylene NUCG-5381 (manufactured by Nippon Unicar) 700g, azodicarbonamide foaming agent
Cellmic C-2” (foaming temperature 204℃: manufactured by Sankyo Kasei)
2kg, organic peroxide "Parkadox 14" (decomposition temperature 158°C: manufactured by Kayaku Nouri) 40g, antioxidant "Irganox 1010" (manufactured by Ciba Geigy) 10g, 2
600 g of silicone gum stock (manufactured by Nippon Unicar) with a viscosity of 300,000 CP at 3°C and a methyl vinyl silicone content of 1.0% was added to DS20-40 manufactured by Moriyama Seisakusho.
The mixture was kneaded at 160° C. for 10 minutes using a MWA-H type kneader. The rotation speed of the blade was 45 rpm. This kneaded material was pelletized. The pellets were formed into a 1 mm thick sheet by compression molding at 150°C. The pressure and time were 100 kg/cm2 and 5 minutes, respectively. When this sheet was placed on a polyester sheet and placed in an oven at 200°C, it foamed uniformly in 9 minutes. When this foam was taken out and allowed to cool to room temperature, it had a thickness of 10 mm.
A foam having an average cell diameter of 0.4 mm was obtained. After this foam was immersed in warm water at 90° C. for 10 minutes, the thickness was measured and found to be 10 mm. Furthermore, when the foam was repeatedly compressed and relaxed in water at 23° C. to force it to absorb water, it absorbed 8.8 g of water per 1 cm 3 .

Comparative Example 3 20 kg of low density polyethylene NUCG-5381 (manufactured by Nippon Unicar), 2 kg of azodicarbonamide foaming agent "Celmic C-2" (foaming temperature 204°C, manufactured by Sankyo Kasei)
, organic peroxide "Parkadox 14" (decomposition temperature 15
8°C: 40g (manufactured by Kayaku Nouri), 10g of antioxidant "Irganox 1010" (manufactured by Ciba Geigy), 600g of silicone gum stock (manufactured by Nippon Unicar) with a viscosity of 300,000 CP at 23°C and a methyl vinyl silicone content of 1.0%. DS20-40MWA manufactured by Moriyama Seisakusho
The mixture was kneaded for 10 minutes at 160°C using a -H type kneader. The rotation speed of the blade was 45 rpm. This kneaded material was pelletized. The pellets were formed into a 1 mm thick sheet by compression molding at 150°C. Pressure and time are each 10
0 kg/cm2 for 5 minutes. When this sheet was placed on a polyester sheet and placed in an oven at 200°C, it foamed uniformly in 7 minutes. When this foam was taken out and allowed to cool to room temperature, a foam with a thickness of 10 mm and an average cell diameter of 0.2 mm was obtained. This foam is 9
After being immersed in warm water at 0° C. for 10 minutes, the thickness was measured and found to be 11 mm.

Example 3 Polypropylene BJ-315 (manufactured by Tonen Chemical) 18 kg,
Low-density polyethylene NUCG-5381 (manufactured by Nippon Unicar) 700g, azodicarbonamide foaming agent "Celmic C-2" (foaming temperature 204°C: manufactured by Sankyo Kasei) 2kg
, organic peroxide "Parkadox 14" (decomposition temperature 15
8°C: 40g (manufactured by Kayaku Nouri), 10g of antioxidant "Irganox 1010" (manufactured by Ciba Geigy), 600g of silicone gum stock (manufactured by Nippon Unicar) with a viscosity of 300,000 CP at 23°C and a methyl vinyl silicone content of 1.0%. DS20-40MWA manufactured by Moriyama Seisakusho
The mixture was kneaded for 10 minutes at 170°C using a -H type kneader. The rotation speed of the blade was 45 rpm. This kneaded material was pelletized. The pellets were compressed into a sheet with a thickness of 1 mm at 160°C. Pressure and time are each 10
0 kg/cm2 for 5 minutes. When this sheet was placed on a polyester sheet and placed in an oven at 200°C, it foamed uniformly in 9 minutes. When this foam was taken out and allowed to cool to room temperature, a foam with a thickness of 10 mm and an average cell diameter of 0.5 mm was obtained. The density of the foam was 0.08 g/cm3. After immersing this foam in warm water at 90°C for 10 minutes, the thickness was measured to be 20.
It was mm. In addition, when the foam was repeatedly compressed and relaxed in water at 23°C to force it to absorb water, it was found that 1cm3
8.0g of water was absorbed per bottle.

[0021]

Effect of the invention: The foam obtained by the present invention has excellent heat resistance, mechanical properties, chemical resistance, etc., and has a uniform cell diameter, so it can be used as a material for construction materials, agricultural materials, filters, etc. It can be applied to automobile interior wall cushions, culture flooring materials, etc. In particular, since the cells are open cells, they are suitable for use in filters.

Claims (3)

[Claims] Claim 1: a) 100 parts by weight of propylene resin;
b) Lower alkenyl group-containing organopolysiloxane 0.
c) 1 to 30 parts by weight of a blowing agent having a foaming temperature (Tf) in the range of 100 to 200°C, and d) an organic peroxide having a 10 minute half-life temperature (Tp) of 110 to 220°C. 0.2 to 10 parts by weight (however, -10℃≦T
p-Tf≦50°C) A composition for an open-cell propylene resin foam. [Claim 2] Processing the composition for open-cell propylene resin foam according to claim (1) into a predetermined shape at a temperature below the decomposition temperature of the blowing agent and below the decomposition temperature of the organic peroxide; A method for producing an open-cell propylene resin foam, the method comprising heating the foam to 130 to 300°C. 3. An open-cell propylene resin foam produced by the method of claim (2).