JPH082986B2 - Open-cell crosslinked ethylene resin foam containing silica-based porous material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an open-cell type cross-linked ethylene-based composition obtained by cross-linking and foaming from a composition for an open-cell type cross-linked ethylene-based resin foam containing a silica-based porous material. It relates to a resin foam.

More specifically, 100 parts by weight of ethylene resin foaming agent 1
To 30 parts by weight and 0.2 to 10 parts by weight of organic peroxide as a cross-linking agent, 0.1 to 10 parts by weight of a trifunctional monomer and 0.1 to 100 parts by weight of silicone oil are added to a cross-linked foaming composition.
5 parts by weight in combination or R ₃ SiO- [R ₂ SiO] _m, - [RXSiO] _s -SiR ₃ (1) and RSi- [0- (R _{2 SiO)} q -Y] ₃ (2) (where, R: 1-valent hydrocarbon X:-[(0) _p- (C _n H
_2n O) _t —R ′] R ′: H, a group selected from an alkyl group, an allyl group, an aralkyl group or a carbamyl group p: 0 or 1 Y: (C _n H _2n O) _t —R ′ m: 0 Silicone block selected from 300 n: 2 to 10 s: 1 to 30 q: 1 to 300 t: 1 to 100 and (C _n H _2n O) is an oxyalkylene group or a mixture of oxyalkylene groups) Copolymer 0.1-5
1 to 3000 parts by weight of a silica-based porous material is added to 100 parts by weight of a composition for an open-cell type crosslinked ethylene-based resin foam obtained by adding any one of parts by weight, and an organic peroxide.
The half-life temperature (Tp) for 10 minutes is 100 to 220 ° C, the foaming temperature (Tf) of the foaming agent is 90 to 220 ° C, and the following formula −10 ° C ≦ Tp−Tf ≦ 50 ° C is satisfied. A film or sheet is formed from the composition for an open-cell type crosslinked ethylene resin foam containing a silica-based porous material, which is obtained by heating at 120 to 300 ° C to foam and crosslink. Further, the present invention relates to an open-cell type crosslinked ethylene resin foam excellent in moisture absorption and dehumidification of external moisture and odor, and gas adsorption.

(Prior Art) Conventionally, zeolite, cristobalite, and other silica-based porous substances are known to be materials that strongly adsorb gases such as ammonia and further have an adsorption / desorption effect.
Its use as a moisture absorbent for gas adsorbents and filters, and as a moisture control material for buildings is being investigated, but if powder of silica-based porous material or pellets is used as is in a container, it will spill or It was very inconvenient to handle as it was picked up. Therefore, a method of using powder or pellet of silica-based porous material wrapped in cloth or paper has been devised, but it has been difficult to form it into a certain shape or cut it into various shapes. . In addition, in order to enable molding, a product obtained by simply mixing a resin such as polyethylene with a powder or pellet of a silica-based porous material and hardening it has almost no moisture permeability or breathability, and the silica-based porous material is not absorbed. It was not possible to make full use of the dehumidifying action and the gas adsorption property.

(Problems to be Solved by the Invention) The present invention is to form a sheet or cut into various shapes without impairing the gas adsorbing property and the absorbing / dehumidifying action of the silica-based porous material. It is intended to manufacture a composite material that can be handled easily. Especially the diameter
For molded products in which the properties of silica-based porous materials are substantially retained by combining silica-based porous materials that are molded into pellets or cylinders of 0.5 mm or more with a small amount of open-cell foam. It is intended to manufacture composite materials.

(Means and Actions for Solving Problems) The inventors of the present invention have previously disclosed Japanese Patent Publication No. Sho 60-49657 and Japanese Patent Laid-Open No. Sho 6-49657.
No. 0-124632 proposes a composition for an open-cell type crosslinked ethylene-based resin foam which is excellent in air permeability, water absorption, weather resistance and the like. That is, in JP-B-60-49657, a crosslinked foaming composition comprising an ethylene resin, a foaming agent, and an organic peroxide as a crosslinking agent is combined with a trifunctional monomer and silicone oil. No. 124632, submitted a composition for an open-cell type crosslinked ethylene resin foam in which a silicone block copolymer is combined with a crosslinked foaming composition comprising an ethylene resin, a foaming agent, and an organic peroxide as a crosslinking agent. However, the problems of the invention are solved by utilizing the techniques of these inventions.

To 100 parts by weight of these open-cell type crosslinked ethylene-based resin foam composition, 1 to 3000 silica-based porous material is added.
By adding parts by weight, a composition for a composite of a silica-based porous material and an open-cell type crosslinked ethylene-based resin foam can be obtained. When the amount of the silica-based porous material added is less than 1 part by weight, the effect of absorbing and dehumidifying cannot be expected substantially,
If the amount is more than 3000 parts by weight, the resin layer does not serve as a binder, and the silica-based porous substance powder or pellets may be scattered.

After heating the composition of the present invention, by cooling, the powder or pellet of the silica-based porous material is incorporated into a part of the open-cell foam, and the gas-adsorbing property or the adsorption / desorption action of the silica-based porous material is obtained. It is possible to obtain a composite material capable of molding a powder of a porous silica material, pellets or other molded articles into a fixed shape or cutting into various shapes without impairing the above.

The silica-based porous material that can be used in the present invention refers to, for example, zeolite, cristobalite, and semi-synthetic products thereof, or synthetic products and the like. Examples of cristobalite-based substances include Chris Barr (manufactured by Nittetsu Mining) and Builder Clay (manufactured by Nittetsu Mining). The silica-based porous material may be in the form of powder, pellets or other molded products. However, in the case of powder with a diameter of 250 μm or less,
With respect to 100 parts by weight of the composition for open-cell type crosslinked ethylene-based resin foam, the addition of 1 to 100 parts by weight gives a uniform composite of the silica-based porous material and the open-cell type crosslinked ethylene-based resin foam. . Further, in the case of powder or pellets having a diameter of 250 μm or more and other molded articles, particularly pellets and other molded articles having a diameter of 0.5 mm or more, 100 to 3000 parts by weight, preferably 1000 to 3000 parts by weight, and sintered. A composite product in or near this state is obtained, and the composite product substantially retains the properties of the silica-based porous material.

In the present invention, the ethylene-based resin is a polymer containing ethylene as a main component, high-pressure polyethylene, linear low-density polyethylene (LLDPE), ethylene-vinyl ester copolymer, ethylene-acrylic ester copolymer, An ethylene-α olefin copolymer and the like.

The organic peroxide used in the present invention has a decomposition temperature of 100 to 220 ° C. with a half-life of 10 minutes, and the following may be mentioned as examples. 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 (11
5), 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-
Butyl peroxymaleic acid (140), cyclohexanone peroxide (145), 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).

The foaming agent used in the present invention has a foaming temperature of 90 ° C.
To 220 ° C., and those in which a decomposition temperature is adjusted to this range by using an accelerator or an auxiliary agent together are also included in this range. Examples include:

Azobisisobutyronitrile, diazocarbonamide, p-toluenesulphonylhydrazide, 4,4'-oxybis (benzenesulphonylhydrazide), n-heptane, n-octane, n-nonane, n-decane.

Examples of trifunctional monomers that can be used in the present invention include triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate and others.

The silicone oil used in the present invention is 1
It is desirable that it is less than 0,000 CS.

Silicone Bro poke copolymer used Te present invention Ioi is, R ₃ SiO- [R ₂ SiO] _m - [RXSiO] _s -SiR ₃ (1) and RSi- [0- (R _{2 SiO)} q -Y] ₃ (2) (However, R: 1 valent hydrocarbon X:-[(0) _p- (C _n H
_2n O) _t —R ′] R ′: H, a group selected from an alkyl group, an allyl group, an aralkyl group or a carbamyl group p: 0 or 1 Y: (C _n H _2n O) _t —R ′ m: 0 300 n: 2 to 10 s: 1 to 30 q: 1 to 300 t: 1 to 100 and (C _n H _2n O) is an oxyalkylene group or a mixture of oxyalkylene groups) is there.

The molecular weight of the silicone block copolymer that can be used in the present invention is preferably 500 or more. If it is less than 500, it may be difficult to mix, and bleeding may occur on the surface of the product after molding.

In the present invention, the 10-minute half-life temperature (T _P ) of organic peroxide
Is 100-220 ℃, the foaming temperature (Tf) of the foaming agent is 90-22
A combination of an organic peroxide and a blowing agent which is 0 ° C. and satisfies the following formula −10 ° C. ≦ Tp−Tf ≦ 50 ° C. is desirable. That is, with this combination, when the composition is heated and then cooled, an open cell foam or an open cell foam partially containing closed cells is obtained.

The amount of organic peroxide required is 0.2 to 10 parts by weight. If the amount is less than 0.2 parts by weight, the viscosity of the resin layer will hardly increase upon heating the composition, and the resin layer will sag. Even if it is more than 10 parts by weight, the improvement of the crosslinking efficiency is little.

The amount of foaming agent is required to be 1 to 30 parts by weight. If it is less than 1 part by weight, there is almost no effect of foaming, and if it is more than 30 parts by weight, the amount of the decomposed product of the foaming agent wastefully escaping into the atmosphere at the time of foaming increases, resulting in poor efficiency.

The amount of trifunctional monomer should be 0.1 to 10 parts by weight. If it is less than 0.1 parts, the effect is hardly recognized, and if it is more than 10 parts, the product surface may ooze out.

The amount of silicone oil required is 0.1-5 parts by weight. If it is less than 0.1 part by weight, bubbles having a uniform fine structure cannot be obtained, and if it is more than 5 parts by weight, oozing may occur.

The amount of silicone block copolymer should be 0.1-5 parts by weight. If it is less than 0.1 part by weight, bubbles having a uniform fine structure cannot be obtained, and if it is more than 5 parts by weight, oozing may occur.

In the present invention, the composition may optionally contain an oxidation stabilizer,
UV stabilizers, inorganic fillers, pigments, flame retardants, rubbers and the like can be added.

The open-cell type crosslinked ethylene resin foam can be produced by a single step of heating the composition, for example, a pellet, a powder or film, a sheet or other molded article, and heating and cooling the composition.

In the present invention, the temperature at which the composition is heated is equal to or higher than the temperature required for foaming and crosslinking, and specifically, it is between 120 and 300 ° C.

In the present invention, the decomposition temperature of the organic peroxide is shown as the temperature at which the half-life of the pure product is 10 minutes, so that crosslinking proceeds even below this temperature.

In the present invention, the heating time of the composition is the time required to produce a foam having open cells, and specifically 1
It is in the range of ~ 60 minutes.

In the present invention, the structure is fixed by heating the composition and then cooling the foam. The cooling temperature is preferably 50 ° C or lower.

As a heating method, heating gas such as air, direct or indirect contact with a heated metal such as iron or aluminum, external heating by infrared rays, burners, electric heating, etc., as well as internal heating such as high frequency heating can be applied. .

Further, depending on the purpose, heating may be performed under normal pressure or under pressure.

 Examples will be given below.

Example 1 100 parts of an ethylene-vinyl acetate copolymer (manufactured by Nippon Unicar) having a melt index of 30 and a vinyl acetate content of 35% by weight was added to an azodicarbonamide-based foaming agent "Celmic CAP" (foaming temperature 130 ° C: three Kyokasei) 4 parts, dicumyl peroxide (decomposition temperature 150 ° C: NOF Corporation) 1
Part, triallyl cyanurate 1 part, silicone oil (100C
S: Made by Nippon Unicar) 1 part with a bumper mixer at 80 ℃
After kneading for 10 minutes, 2000 parts of granular Krisvar (manufactured by Nittetsu Mining Co., Ltd.) having a diameter of 3 mm and a length of 5 mm was added, and after further kneading for 10 minutes, it was heated with a hot press at 180 ° C for 10 minutes, and then at room temperature for 1 hour. The mixture was gradually cooled to 1 to obtain a plate-shaped foam molded product having a thickness of 15 mm, a length of 550 mm, and a width of 580 mm. When this plate-shaped foamed article was made to absorb water, it contained 45 g of water per 100 g. The plate-shaped foamed product was dropped from the height of 1 m on the floor, but it was not damaged.

Example 2 100 parts of an ethylene-ethyl acrylate copolymer having a melt index of 20 and an ethyl acrylate content of 20% by weight (manufactured by Nippon Unicar Co., Ltd.) was used as an azodicarbonamide-based foaming agent "Celmic CAP" (foaming temperature 130 ° C). : 4 parts of Sankyo Kasei), 1 part of dicumyl peroxide (decomposition temperature 150 ° C: made by NOF Corporation), 1 part triallyl isocyanurate, 1 part of silicone oil (50CS: made by Nippon Unicar) on a roll mill at 80 ° C. After kneading for 25 minutes, add 25 parts by weight of Builder Clay (made by Nittetsu Mining Co., Ltd.) with an average particle size of 100
What was kneaded for a minute was pelletized.

This pellet was compressed into a sheet having a thickness of 1 mm at 90 ° C. Pressure and time are 100kg / cm ² , 5 respectively
It was a minute. This sheet was placed on a wire mesh of 200 mesh, heated in an oven at 180 ° C for 7 minutes, and then allowed to cool. As a result, a foam having a soft texture and a continuous open cell with a thickness of 3 mm and an average diameter of 0.3 mm was formed. Was obtained. The air permeability of this foam was 40 when the air passage speed of the B5 filter paper was 100. The foam was vacuum dried at room temperature for 24 hours and then placed in a desiccator to make it have an atmosphere of 90% relative humidity. After 24 hours, the weight of the foam increased by 8 g per 100 g of the foam. Similarly, when placed in an ammonia gas atmosphere, a weight increase of 60 mg per 100 g of the foam was observed after 24 hours. This foam could be easily cut with scissors.

Example 3 Melt index 5, ethylene having a density of 0.895 g / cm ³
Azodicarbonamide-based blowing agent "Celmic CA" for 100 parts of α-olefin copolymer (made by Union Carbide)
P500 "(foaming temperature 150 ° C: Sankyo Kasei) 10 parts triallyl trimellitate 1 part, perhexin 25B (decomposition temperature 170
℃: 1 part of Nippon Oil & Fats and 1 part of silicone oil (50CS: Nippon Unicar) were kneaded with a Banbury mixer at 125 ° C for 10 minutes, and then 30 parts by weight of Builder Clay (made by Nippon Mining Co., Ltd.) having an average particle size of 50 mesh. The mixture was added and kneaded for 10 minutes, and then pelletized. The pellet was compression-molded into a sheet having a thickness of 2 mm, placed on an aluminum plate, heated in a pine oven at 200 ° C. for 5 minutes, taken out, and allowed to cool. The obtained foam was an open-cell type foam having a thickness of 8 mm and 0.30 g / cm ³ . This foam could be easily cut with scissors.

Example 4 100 parts of an ethylene-vinyl acetate copolymer (manufactured by Nippon Unicar) having a melt index of 30 and a vinyl acetate content of 35% by weight was added to an azodicarbonamide-based foaming agent "Celmic CAP" (foaming temperature 130 ° C: 3%). Kyokasei) 4 parts, dicumyl peroxide (decomposition temperature 150 ° C: NOF Corporation) 1
Parts, silicone Bro poke copolymers CH ₃ Si _{[O {(CH 3) 2 SiO} } 6 (C 2 H 4 O) 20 (C 3 H 6 O) 20 C 4 H 9 ] (1,000 cs: manufactured by Nippon Unicar) 1 part Was mixed with a Banpary mixer at 80 ° C for 10 minutes, then 2000 parts of granular Krisvar (manufactured by Nittetsu Mining Co., Ltd.) having a diameter of 3 mm and a length of 5 mm was added, and the mixture was kneaded for 10 minutes and heated at 180 ° C for 10 minutes with a hot press. Then slowly cool to room temperature over 1 hour, thickness 15mm, length 550mm, width 580
A plate-shaped foam molded product having a size of mm was obtained. When this plate-shaped foamed article was made to absorb water, it contained 45 g of water per 100 g.
The plate-shaped foamed product was dropped from the height of 1 m on the floor, but it was not damaged.

Example 5 100 parts of an ethylene-ethyl acrylate copolymer having a melt index of 20 and an ethyl acrylate content of 20% by weight (manufactured by Nippon Unicar Co., Ltd.) was used as an azodicarbonamide-based foaming agent “Celmic CAP” (foaming temperature 130 ° C.). : Sankyo Kasei) 4 parts, dicumyl peroxide (decomposition temperature 150 ° C: made by NOF Corporation) 1 part, silicone block copolymer (CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] ₃₅ [(CH ₃ ) (OC ₂ H ₄ ) ₄ (OC ₃ H ₆ ) _4- OC ₄ H ₈ Si (CH ₃ ) O] ₃ Si (CH ₃ ) ₃ (1,000CS: made by Nippon Unicar) 1 part with a roll mill at 80 ° C
After kneading for 10 minutes, 25 parts by weight of builder clay having an average particle size of 100 mesh (manufactured by Nittetsu Mining Co., Ltd.) was added, and the mixture was kneaded for 10 minutes, and pelletized.

This pellet was compressed into a sheet having a thickness of 1 mm at 90 ° C. Pressure, time is, respectively, 100 kg / cm ^2,
It took 5 minutes. This sheet was placed on a wire mesh of 200 mesh, heated in an oven at 180 ° C for 7 minutes, and then allowed to cool. As a result, a foam having a soft texture and a continuous open cell with a thickness of 3 mm and an average diameter of 0.3 mm was formed. Was obtained. The air permeability of this foam was 40 when the air passage speed of the B5 filter paper was 100. The foam was vacuum dried at room temperature for 24 hours and then placed in a desiccator to make it have an atmosphere of 90% relative humidity. After 24 hours, the weight of the foam increased by 8 g per 100 g of the foam. Similarly, when placed in an ammonia gas atmosphere, a weight increase of 60 mg per 100 g of the foam was observed after 24 hours. This foam could be easily cut with scissors.

Example 6 Melt index 5, ethylene having a density of 0.895 g / cm ³
Azodicarbonamide-based blowing agent "Celmic CA" for 100 parts of α-olefin copolymer (made by Union Carbide)
P500 "(foaming temperature 0.99 ° C.: Sankyo Chemical Co., Ltd.) 10 parts, Pahekishin 25B (decomposition temperature 170 ° C.: manufactured by NOF), 1 part of silicone Bro poke copolymer (CH _{3) 3} SiO [(CH _{3) 2} SiO] ₆₅ [ _{(CH 3) (OC 2 H} 4) 16 (OC 3 H 6) 2 -CO 4 H 8 Si (CH 3) O ] _{4 Si (CH 3) 3 (} 1,000CS: Nippon Unicar Ltd.) 1 part Banbury mixer After kneading at 125 ° C for 10 minutes, add 30 parts by weight of Builder Clay (manufactured by Nittetsu Mining Co., Ltd.) with an average particle size of 50 mesh, and
What was kneaded for 10 minutes was pelletized. The pellet was compression-molded into a sheet having a thickness of 2 mm, placed on an aluminum plate, heated in a pine oven at 200 ° C. for 5 minutes, taken out, and allowed to cool. The resulting foam has a thickness of 8 mm and 0.30 g / cm ³
It was an open-cell type foam. This foam could be easily cut with scissors.

Comparative Example 1 In the same manner as in Example 2, the foam obtained without adding Hilder Clay was vacuum dried at room temperature for 24 hours, then placed in a desiccator and placed in an atmosphere of 90% relative humidity. There was a weight gain of 1.5g per 100g of body. Similarly, when placed in an ammonia gas atmosphere, a weight increase of 5 mg per 100 g of the foam was observed after 24 hours.

(Effect of the Invention) The composite of the silica-based porous material and the ethylene-based resin foam obtained from the composition of the present invention almost impairs the properties of the silica-based porous material such as the adsorption / desorption function and the gas adsorption property. It is a composite material that can be molded into a sheet shape or cut into various shapes without being used, and is used for a moisture absorption filter, a gas adsorption filter, a humidity control sheet, and the like.

Claims (1)

[Claims] 1. An ethylene resin 100 parts by weight, a foaming agent 1 to 30.
0.1 to 10 parts by weight of a trifunctional monomer and 0.1 to 100 parts by weight of a silicone oil, based on a crosslinkable foaming composition comprising 0.2 to 10 parts by weight of an organic peroxide as a crosslinking agent.
5 parts by weight in combination or R ₃ SiO- [R ₂ SiO] _m, - [RXSiO] _s -SiR ₃ (1) and RSi- [0- (R _{2 SiO)} q -Y] ₃ (2) (where, R: 1 monovalent hydrocarbon X: - _{[(0) p - (C n} H 2n O) t -R ' ] R': H, an alkyl group, an allyl group, a group selected from aralkyl or carbamyl p: 0 or 1 Y: (C _n H _2n O) _t −R ′ m: 0 to 300 n: 2 to 10 s: 1 to 30 q: 1 to 300 t: 1 to 100 and (C _n H _2n O) Is an oxyalkylene group or a mixture of oxyalkylene groups) 0.1 to 5
1 to 3000 parts by weight of the silica-based porous material per 100 parts by weight of the composition for open-cell type crosslinked ethylene-based resin foam prepared by adding any one of the parts by weight, and organic peroxide The 10-minute half-life temperature (Tp) of the product is 100 to 220 ℃, the foaming temperature (Tf) of the foaming agent is 90 to 220 ℃, and the following formula −10 ℃ ≦ Tp−Tf ≦ 50 ℃ is satisfied. Forming a film or sheet from a composition for open-cell type crosslinked ethylene resin foam containing a silica-based porous material characterized in that it is foamed and crosslinked by heating it at a temperature of 120 to 300 ° C. An open-cell crosslinked ethylene-based resin foam obtained by, which is excellent in moisture absorption and dehumidification of external moisture, odor, and gas adsorption.