JP2001131320A - Rubber-based foaming material and its foamed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a rubber-based foaming material capable of forming an ethylene-propylene-based rubber foamed product, excellent in flame retardancy showing a short combusting time and small amount of residue conforming to the combustion standard UL94HF-1, and hardly generating a corrosion or an environmental problem. SOLUTION: This rubber-based foaming material consists of an admixture containing at least an ethylene-propylene-based rubber, a blowing agent, bis- pentabromodiphynylethylene, aluminum hydroxide and magnesium hydroxide as components, and the rubber-based foamed product consisting of the foamed product of the above rubber-based forming material is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber foam material which can form an ethylene / propylene rubber foam which has excellent flame retardancy and hardly causes corrosion and environmental problems.

[0002]

2. Description of the Related Art An ethylene / propylene rubber foam is
Based on its excellent cushioning and compressibility properties, cushioning materials and padding materials, sealing materials such as airtightness and waterproofness, heat insulation materials and soundproofing materials, indoor products such as home appliances, outdoor products such as automobiles, and buildings such as houses Although it is widely used in various fields such as materials, its flame retardancy is an urgent issue.

[0003] That is, conventionally, such foams are:
One or more of chlorinated polyethylene, chlorinated paraffin, decabromodiphenyl ether and antimony trioxide and aluminum hydroxide have been used to make them flame-retardant. It has been pointed out that decabromodiphenyl ether causes environmental problems due to the generation of dioxin, and antimony trioxide also causes environmental problems due to harmful effects, and its use is concerned, and an alternative flame retardant method is required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to develop a rubber-based foamed material which can form an ethylene / propylene-based rubber foam which has excellent flame retardancy and hardly causes corrosion and environmental problems.

[0005]

The present invention provides an ethylene-propylene rubber, a foaming agent, ethylenebispentabromodiphenyl,
An object of the present invention is to provide a rubber-based foamed material comprising a mixture containing at least aluminum hydroxide and magnesium hydroxide as components.

[0006]

According to the present invention, an ethylene / propylene rubber having a short flame burning time and a short residue, exhibiting excellent flame retardancy conforming to the combustion standard UL94HF-1, and hardly causing corrosion and environmental problems. A foam can be obtained. This is due to the combination of the above flame retardants. That is, while ethylene bispentabromodiphenyl generates hydrogen bromide by its decomposition and shuts off oxygen in its gas phase, aluminum hydroxide and magnesium hydroxide are heated from the low temperature side of about 200 ° C. to 400 ° C.
It exhibits an almost continuous heat absorption effect up to the high temperature side of about ° C., exhibits excellent flame retardancy, and is unlikely to cause corrosion or environmental problems by those substances.

[0007] In the above, if ethylenebispentabromodiphenyl is lacking, the flame burning time becomes longer, and if aluminum hydroxide and magnesium hydroxide are lacking, the residue becomes longer. Accordingly, the use of ethylene bispentabromodiphenyl, aluminum hydroxide, or magnesium hydroxide alone or in combination with one of them lacks flame burning time or prolongs the residue, resulting in the above combustion standard UL94HF-1. Is not obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber-based foamed material according to the present invention comprises an ethylene / propylene rubber, a foaming agent, an ethylene bispentabromodiphenyl, an admixture containing at least aluminum hydroxide and magnesium hydroxide.

As the ethylene-propylene rubber, one or more suitable ones such as ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber, and ethylene-propylene terpolymer can be used. There is no. EPDM, especially Mooney viscosity (ML _{1 + 4} , 100 ° C., the same applies hereinafter) of 100 or less, preferably 70 or less, particularly 5 to 50 is preferred from the viewpoint of the controllability of rubber properties such as compressibility and sealing performance. Can be used.

One or more suitable foaming agents can be used, and there is no particular limitation. Incidentally, examples thereof include inorganic foaming agents such as ammonium carbonate and ammonium hydrogen carbonate, sodium hydrogen carbonate and ammonium nitrite, sodium borohydride and azides.

Also, fluorinated alkanes such as trichloromonofluoromethane and dichloromonofluoromethane, azobisisobutyronitrile and azodicarboxylic amide (AD
CA), azo compounds such as barium azodicarboxylate, p-toluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,
4'-oxybis (benzenesulfonylhydrazide),
Organic blowing agents such as hydrazine compounds such as allyl bis (sulfonyl hydrazide) are also included.

Further, semicarbazide compounds such as ρ-toluylenesulfonyl semicarbazide and 4,4′-oxybis (benzenesulfonyl semicarbazide), triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; Organic foaming agents such as N-nitroso-based compounds such as N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide are also included. The foaming agent to be used may be heat-expandable fine particles in which a heat-expandable substance is encapsulated in microcapsules. The heat-expandable fine particles include commercially available products such as microspheres (trade name, manufactured by Matsumoto Yushi Co., Ltd.).

The amount of the foaming agent can be appropriately determined according to the physical properties of the desired foam. Generally, a foaming agent is used in an amount of 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, particularly 1 to 30 parts by weight, per 100 parts by weight of the ethylene / propylene rubber.

As the flame retardant for imparting flame retardancy, three kinds of ethylene bispentabromodiphenyl, aluminum hydroxide and magnesium hydroxide are used in combination. The blending amount can be determined as appropriate. However, ethylene bispentabromodiphenyl is used in an amount of 5% based on the solid content of the admixture from the viewpoint of lowering the density due to a high expansion ratio and maintaining a rubbery texture by suppressing curing. -50% by weight, preferably 10-40% by weight, especially 15-35% by weight, 2-30% by weight of aluminum hydroxide and magnesium hydroxide, especially 3-25% by weight, especially 5-20% by weight. It is preferable to use a composition.

The blend is prepared by mixing at least the components comprising ethylene / propylene rubber, a foaming agent, ethylenebispentabromodiphenyl, aluminum hydroxide, magnesium hydroxide, etc., through a kneader such as a kneader or a mixing roll. It can be carried out by mixing in an appropriate method such as a method of mixing by mixing.

In preparing the admixture, an appropriate compounding agent similar to the conventional one for the purpose of controlling the viscosity and the physical properties of the foam to be obtained, especially the one which does not easily cause the above-mentioned corrosion problems and environmental problems. It can be added as needed. Incidentally, a vulcanizing agent can be blended for the purpose of improving the strength by the vulcanizing treatment, and the vulcanizing agent is not particularly limited, and one or more suitable vulcanizing agents can be used.

Specific examples of the vulcanizing agent include sulfur and sulfur compounds, selenium and magnesium oxide, lead monoxide and zinc oxide, organic peroxides and polyamines, P-quinone dioxime and P, P '. -Oximes such as dibenzoylquinone dioxime, nitroso compounds such as P-dinitrosobenzine, alkylphenol-formaldehyde resin,
Examples include resins such as melamine-formaldehyde condensate and ammonium salts such as ammonium benzoate.

Sulfur and sulfur compounds, particularly sulfur, can be preferably used from the viewpoint of physical properties such as durability due to vulcanizability and foamability of the obtained foam. The amount of the vulcanizing agent can be appropriately determined according to the vulcanizing efficiency based on the type of the vulcanizing agent. By the way, in the case of sulfur, usually 0.1 to 10 parts by weight per 100 parts by weight of ethylene-propylene rubber,
In particular, 0.5 to 5 parts by weight are used. When a vulcanizing agent is compounded, a mixing method in which the temperature rises to such an extent that vulcanization proceeds in the preparation of the admixture is not preferred.

For the purpose of accelerating the above-mentioned vulcanization treatment, the admixture may be, for example, guanidines, thiazoles, sulfenamides, turams, dithiocarbamic acids, xanthogenic acids, aldehyde ammonias, aldehydeamines, thioureas. One or two or more kinds of vulcanization accelerators, and vulcanization acceleration aids can be blended. The amount of the vulcanization accelerator used is suitably 0.1 to 10 parts by weight per 100 parts by weight of the ethylene / propylene rubber, but is not limited thereto.

Further, the admixture includes drying oils such as paraffins, waxes, naphthenes, aromas, asphalts, linseed oil, animal and vegetable oils, petroleum oils, various kinds of oils for the purpose of controlling moldability and the like. One or more softeners or plasticizers comprising low-molecular-weight polymers, phthalates and phosphates, stearic acid and esters thereof, alkyl sulfonates and tackifiers, particularly difficult Those having a higher flash point than that of improving the flammability can also be added. In addition, stearic acid and its esters are also useful as a lubricant and the like, and are therefore examples of components that can also contain various lubricants.

The admixture may further contain an organic acid such as phthalic anhydride, benzoic acid or salicylic acid, N-nitroso-diphenylamine, N-nitroso-phenyl-β- One or more vulcanization retarders composed of amines such as naphthylamine may be blended to delay vulcanization contrary to the vulcanization accelerators described above.

In addition, the admixture includes foaming aids such as urea, salicylic acid and benzoic acid, calcium carbonate and talc,
Conventional fillers such as clay and mica powder, zinc white and bentonite, carbon black and silica, alumina and aluminum silicate, magnesium oxide and aluminum powder, antioxidants, antioxidants and pigments, coloring agents and fungicides One or more appropriate compounding agents other than the flame retardant can be added as necessary. The zinc white is useful as a stabilizer, and carbon black is also useful as a reinforcing agent. Accordingly, examples of the components that can also contain various stabilizers and reinforcing agents are given.

In addition, one or more rubber-based polymers other than non-rubber-based polymers and ethylene-propylene-based rubbers are blended in the mixture for the purpose of controlling physical properties such as the strength of the obtained foam. You can also. As the non-rubber-based polymer or rubber-based polymer, an appropriate one can be used, and there is no particular limitation.

Incidentally, examples of the non-rubber-based polymer include acrylic polymers such as poly (meth) acrylic acid alkyl ester, polyethylene, polypropylene and ethylene-vinyl acetate copolymer, polyvinyl acetate and polyamide, polyester and urethane-based polymers. Polymers, styrene-based polymers, silicone-based polymers, epoxy-based resins, and the like. The amount used is preferably 50% by weight or less, more preferably 30% by weight or less, and particularly preferably 15% by weight or less, of the ethylene / propylene rubber from the viewpoint of maintaining the rubber-like properties of the foam.

On the other hand, examples of the rubber-based polymer other than the above-mentioned ethylene-propylene-based rubber include a cyclic or non-cyclic compound having a non-conjugated double bond such as α-olefin dicyclopentadiene such as butene-1 or ethylidene norbornene. Rubber-based copolymers and silicone rubbers, fluorine rubbers and acrylic rubbers, polyurethane rubbers and polyamide rubbers, natural rubber and polyisobutylene,
Polyisoprene, butyl rubber, nitrile butyl rubber, styrene / butadiene rubber, styrene / butadiene / styrene rubber, styrene / isoprene / styrene rubber, styrene / ethylene / butadiene rubber, styrene / ethylene / butylene / styrene rubber, styrene / isoprene / propylene / styrene Rubber and the like. ethylene·
The amount of the rubber-based polymer other than the propylene-based rubber may be the same as in the case of the non-rubber-based polymer.

The foam using the rubber-based foamed material according to the present invention is formed by heating and foaming the above-mentioned admixture, and by vulcanizing and foaming when a vulcanizing agent is contained. Although it can be performed, at the time of its formation, if necessary, the mixture is molded into a predetermined form such as a sheet,
The molded body can be heat-treated to form a foam.
In that case, the molded body may be formed into an arbitrary form by an appropriate method, and the form is not particularly limited.

Accordingly, the object to be subjected to the foaming treatment may be an admixture formed into a sheet or other form by an appropriate method such as a mixing roll, a calender roll, or extrusion molding, or a predetermined mold. It may be formed into a predetermined form having irregularities and the like by an appropriate method such as injection molding or press molding through the like.

In the above, in the formation of the foam having the uneven shape, the molded sheet is placed on a mold having the unevenness and heated, and the mixture forming the sheet is flowed into the unevenness of the mold to form the foam. A processing method can be adopted. Such a method has an advantage that the uneven shape can be accurately formed even in the case of a mold having a complicated and deep uneven structure having a fold structure. The same applies when forming a vulcanized foam.

Therefore, the size of the molded article is arbitrary, and can be appropriately determined according to the desired form of the foam. In the case of a sheet or the like, the thickness is generally 100 mm or less, preferably 1 μm to 80 mm, particularly 10 μm to 50 mm.

The above foaming treatment or vulcanization foaming treatment comprises:
It can be carried out under appropriate conditions according to the related art, depending on the foaming temperature of the foaming agent or vulcanizing agent used, the vulcanization start temperature, and the like. The general processing temperature is 450 ° C or less, especially 100 ~
350 ° C, especially 120-300 ° C. Generally, the foaming treatment softens the admixture, expands the foaming agent, and forms a foamed structure to form a desired foam. Also, in the vulcanization and foaming treatment, the mixture softens and the foaming agent expands to form a foamed structure, and vulcanization proceeds to form a desired vulcanized foam.

In the above, the foaming treatment can be performed under pressure for the purpose of adjusting the expansion ratio and the like. The pressurizing condition can be according to the conventional. In the case of vulcanization / foaming treatment, the foaming treatment and vulcanization treatment can be performed under different temperature conditions, and appropriate treatment conditions can be adopted.

The expansion ratio (density ratio before and after foaming) of the foam or vulcanized foam to be formed can be appropriately determined according to the purpose of use and the like. Generally, the density is 1.1 to 25 times, especially 1.5 to 20 times, but the density is 0.01 to 0.5 g.
/ Cm ³ foam can be preferably used for various applications. The expansion ratio can be controlled by the amount of the above-mentioned blowing agent, the processing time and temperature of vulcanization and expansion, and the like. In addition, by controlling the expansion ratio, it is possible to control the foaming structure of the obtained foams, such as independent or continuous, and their mixture.

The rubber-based foam according to the present invention includes various conventional materials such as cushioning materials and padding materials, sealing materials for various purposes such as airtightness and waterproofing, heat insulating materials, and vibration reducing materials such as soundproofing and vibration suppression. It can be preferably used for applications.

[0034]

EXAMPLES Example 1 EPDM having Mooney viscosity of 23 (EPT4 manufactured by Mitsui Chemicals, Inc.)
021) 100 parts (parts by weight, hereinafter the same), ADCA20
Parts, urea-based foaming aid 5 parts, ethylene bispentabromodiphenyl 100 parts, aluminum hydroxide 50 parts, magnesium hydroxide 50 parts, sulfur 1.5 parts, dithioate-based vulcanization accelerator 1.2 parts, thiazole 1.0 part of a system vulcanization accelerator, 10 parts of carbon black, 5 parts of zinc oxide, 3 parts of powdered stearic acid, 35 parts of process oil and 1 part of polyethylene glycol are kneaded with a pressure kneader to obtain an admixture. An unvulcanized sheet having a thickness of 10 mm was obtained by molding with an extruder. The sheet was heated in an oven at 160 ° C. for 20 minutes to perform vulcanization and foaming treatment to obtain a foamed sheet.

Comparative Example 1 A foamed sheet was obtained in the same manner as in Example 1, except that aluminum hydroxide and magnesium hydroxide were not used.

Comparative Example 2 Ethylene bispentabromodiphenyl and magnesium hydroxide were not blended, and the amount of aluminum hydroxide used was 10
A foamed sheet was obtained in the same manner as in Example 1 except that the amount was 0 part.

Comparative Example 3 Ethylene bispentabromodiphenyl and aluminum hydroxide were not blended, and the amount of magnesium hydroxide used was 10
A foamed sheet was obtained in the same manner as in Example 1 except that the amount was 0 part.

Comparative Example 4 Ethylene bispentabromodiphenyl was not added, and the amount of aluminum hydroxide and magnesium hydroxide used was 10
A foamed sheet was obtained in the same manner as in Example 1 except that the amount was 0 part.

Comparative Example 5 A foamed sheet was obtained in the same manner as in Example 1 except that magnesium hydroxide was not used and aluminum hydroxide was used in an amount of 100 parts.

Comparative Example 6 A foamed sheet was obtained in the same manner as in Example 1, except that aluminum hydroxide was not used and that the amount of magnesium hydroxide used was changed to 100 parts.

Evaluation Test The foamed sheets obtained in Examples and Comparative Examples were examined for their density and whether or not they conformed to the flame retardancy according to the flame retardancy standard UL94HF-1. The results are shown in the following table. Example 1 Comparison 1 Comparison 2 Comparison 3 Comparison 4 Comparison 5 Comparison 6 Density (g / cm ³ ) 0.09 0.08 0.08 0.09 0.11 0.09 0.09 Flame retardant Compatible Nonconforming Nonconforming Nonconforming Nonconforming Nonconforming

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yutaka Kuryu 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Manabu Matsunaga 1-1-2 Shimohozumi, Ibaraki-shi, Osaka No. Nitto Denko Corporation (72) Inventor Kazumasa Tanaka 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4F074 AA25 AC19 AC20 AD02 AG10 BA03 BA04 BA05 BA06 BA08 BA13 BA14 BA15 BA17 BA18 BA19 BA20 BA53 BA56 BA91 BB02 BB05 BB06 BB07 BB08 BB09 BB10 BB27 CC04Y CC04Z CC22X CC24X DA32 DA39 DA40 4J002 BB151 DE079 DE148 DE226 DF006 DF016 DF036 DK006 EB066 FD 137 006 FD140 FD150 FD170 FD180 FD326 FD340 GJ02 GL00

Claims (3)

[Claims] 1. An ethylene / propylene rubber, a foaming agent,
A rubber-based foamed material comprising a mixture containing at least ethylenebispentabromodiphenyl, aluminum hydroxide and magnesium hydroxide. 2. A rubber foam comprising a foam of the rubber foam material according to claim 1. 3. The method according to claim 2, wherein the density is 0.01 to
A rubber foam having a weight of 0.5 g / cm ³ .