JP2000344921A - Rubber-based foam material and its foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber-based foam material capable of attaining retardation of combustion without using a flame-retardant and forming an EPDM-based foam having excellent balance of various performances. SOLUTION: This rubber-based foam material comprises an admixture composed of an EPDM having 5-30 Mooney viscosity (MLl+4, 100 deg.C), a vulcanizing agent, a blowing agent and calcium carbonate, magnesium carbonate, silicic acid or a silicate at least as components in amounts of 80-400 pts.wt. of the total of calcium carbonate, magnesium carbonate, silicic acid or a silicate based on 100 pts.wt. of the EPDM. Consequently the rubber-based foam material can control performances such as cushioning properties, compressibility, etc., while excellently preserving rubber properties of EPDM-based foam even in compounding of a large amount of a filler except a flame-retardant capable of controlling combustion characteristics and can be provided with combustion retardation without using a flame-retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EPD exhibiting combustion retardancy.
The present invention relates to a rubber-based foam material capable of forming an M-based foam.

[0002]

2. Description of the Related Art EPDM-based foams are used as cushioning materials and pad materials, sealing materials such as airtight and water-blocking materials, heat insulating materials and soundproofing materials, and as indoor materials for household appliances and the like based on their excellent cushioning properties and compressibility. It is widely used in various fields such as articles, outdoor articles such as automobiles, buildings such as houses, and the properties such as cushioning property and compressibility are adjusted according to the use.

[0003] However, in the past, regarding the flame retardancy of the foam, olefin polymers such as EPDM have high combustion energy. For example, metal oxides, phosphorus compounds, halides, silicone compounds, etc. The method of mixing a heating agent has been exclusively used. For this reason, there has been a problem that it is difficult to balance the difficulty of burning the product with other performances, such as an excessive quality of only the flame retardancy.

[0004]

The present invention relates to a rubber-based foam material capable of forming an EPDM foam having an excellent balance of various performances by achieving a delay in combustion without using a generally used flame retardant. The task is to develop

[0005]

SUMMARY OF THE INVENTION The present invention provides Mooney viscosity (ML).
_{1 + 4} , 100 ° C.) of 5 to 30 EPDM, a vulcanizing agent, a foaming agent, and a mixture containing at least calcium carbonate, magnesium carbonate, silicic acid or silicates, and calcium carbonate per 100 parts by weight of the EPDM. ,
An object of the present invention is to provide a rubber-based foamed material containing 80 to 400 parts by weight of magnesium carbonate, silicic acid or silicates in total thereof.

[0006]

By using the above-mentioned EPDM,
It is possible to mix a large amount of fillers other than flame retardants that can control the combustion characteristics, and it is possible to control the properties such as cushioning and compressibility of the EPDM foam while preserving the physical properties of the rubber. It is possible to provide combustion retardation without using a fuel. Further, when a plasticizer oil having a high flash point is used in combination, it is possible to improve the combustion retardation.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A rubber-based foamed material according to the present invention has an EP having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 to 30.
DM, a vulcanizing agent, a foaming agent, and a mixture containing at least calcium carbonate, magnesium carbonate, silicic acid or silicates, wherein calcium carbonate, magnesium carbonate, silicic acid or silicates per 100 parts by weight of the EPDM Is contained in a total amount of 80 to 400 parts by weight.

As EPDM, Mooney viscosity (ML)
_{(1 + 4} , 100 ° C., the same applies hereinafter) 5 to 30 may be used alone or in combination of two or more. With EPDM having a viscosity outside the above range, it is difficult to adjust properties such as combustion retardation and compressibility while retaining rubber physical properties. The preferred Mooney viscosity of EPDM is 8-25. When two or more types of EPDM satisfying the Mooney viscosity are used, one of the EPDMs is used in consideration of the operability and the like of adjusting the performance.
It is preferable to use 5 to 5 parts by weight and the other in a proportion of 5 to 95 parts by weight.

As the vulcanizing agent, one or more appropriate ones can be used, and there is no particular limitation. Examples include sulfur and sulfur compounds, selenium and magnesium oxide, lead monoxide and zinc oxide, organic peroxides and polyamines, P-quinone dioxime and P, P'-dibenzoylquinone dioxime. Examples thereof include oximes and nitroso compounds such as P-dinitrosobenzine, resins such as alkylphenol-formaldehyde resin and melamine-formaldehyde condensate, and ammonium salts such as ammonium benzoate.

Sulfur and sulfur compounds, especially 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 a sulfur type, usually 0.1 to 10 parts by weight, especially 0.5 to 5 parts by weight is used per 100 parts by weight of EPDM.

One or more appropriate 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, azo compounds such as azobisisobutyronitrile and azodicarboxylic acid amide, barium azodicarboxylate, paratoluenesulfonylhydrazide and diphenylsulfone-
Organic foaming agents such as hydrazine compounds such as 3,3'-disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide) and allylbis (sulfonylhydrazide) 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 to be used can be appropriately determined according to the physical properties of the desired foam. Generally, 0.1 to 100 parts by weight, especially 0.5 to 50 parts by weight, especially 1 to 30 parts by weight, of a blowing agent is used per 100 parts by weight of EPDM.

The rubber-based foamed material contains at least one or more of calcium carbonate, magnesium carbonate, silicic acid and silicates in order to impart flame retardancy. The compounding amount is 80 to 400 parts by weight based on the total amount of calcium carbonate, magnesium carbonate, silicic acid or silicates per 100 parts by weight of EPDM.

When the amount is less than 80 parts by weight, the effect of delaying combustion is poor. When the amount is more than 400 parts by weight, the rubber-like properties are deteriorated, and it is difficult to control the performance of the obtained foam. From the viewpoint of the effect of imparting combustion retardation and the controllability of foam performance, the preferred amount of the calcium carbonate or the like is 380 parts by weight or less, particularly 350 parts by weight or less,
Particularly, it is 100 to 300 parts by weight.

The preparation of the admixture is carried out by an appropriate method such as a method in which at least a compounding component comprising EPDM, a vulcanizing agent, a foaming agent and the above-mentioned calcium carbonate is mixed through a kneader such as a kneader or a mixing roll. Can be carried out by mixing. At this time, a mixing method in which the temperature is raised to such an extent that vulcanization proceeds is not preferable.

In the preparation of the above-mentioned admixture, an appropriate compounding agent according to the prior art can be added for the purpose of adjusting the viscosity and vulcanizability, adjusting the physical properties such as the strength of the obtained foam and the like. Incidentally, for the purpose of accelerating vulcanization, for example, one or two or more of guanidines and thiazoles, sulfenamides and tulams, dithiocarbamic acids and xanthogenic acids, aldehyde ammonias and aldehyde amines, thioureas and the like A vulcanization accelerator and further a vulcanization acceleration aid can be blended. The amount of the vulcanization accelerator used is suitably from 0.1 to 10 parts by weight per 100 parts by weight of EPDM, but is not limited thereto.

The admixture may contain an organic acid such as phthalic anhydride, benzoic acid or salicylic acid, N-nitroso-diphenylamine or N-nitroso-phenyl-β-naphthylamine for the purpose of controlling the processability or moldability. One or two or more vulcanization retarders composed of amines or the like may be blended to delay vulcanization in the opposite manner to the vulcanization accelerators described above.

The admixture may further contain, for the purpose of controlling formability, for example, paraffins such as chlorinated paraffins and waxes, drying oils such as naphthenes, aromas and asphalts, linseed oil, and animal and vegetable oils. One or two of petroleum oils, various low molecular weight polymers, phthalates and phosphates, stearic acid and its esters, alkyl sulfonates and tackifiers, etc.
More than one softener or plasticizer may 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 plasticizer which can be more preferably used, for example, has a flash point of 200 to 350 ° C., preferably 22
These oils are 0 to 330 ° C., and in consideration of more improving moldability and maintaining the rubber properties of the obtained foam, 30 to 500 mm ² / sec at 40 ° C., especially 60 to 450 mm.
mm ² / sec, 5~50mm ² / sec at 100 ℃, especially 10 to 4
Those exhibiting a kinematic viscosity of 0 mm ² / sec are particularly preferred. In addition, the compounding amount of the plasticizer oil more preferable from this point is EPDM.
15 to 40 parts by weight, especially 20 to 35 parts per 100 parts by weight
Parts by weight.

In addition, the admixture may contain urea-based, salicylic acid-based, benzoic acid-based foaming aids, talc, clay, mica powder,
Appropriate excluding conventional flame retardants such as fillers such as zinc white, bentonite, carbon black and silica, alumina and aluminum silicate, acetylene black and aluminum powder, antioxidants, antioxidants and pigments, coloring agents and fungicides One or more of the various compounding agents 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.

Further, a non-rubber polymer or EP may be added to the mixture for the purpose of controlling physical properties such as strength of the obtained foam.
One or more rubber-based polymers other than DM may be blended. 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 polymer include acrylic polymers such as poly (meth) acrylic acid alkyl ester, polyvinyl chloride, polyethylene and polypropylene, ethylene / vinyl acetate copolymer, polyvinyl acetate, polyamide and the like. Examples include polyester, chlorinated polyethylene, urethane-based polymers, styrene-based polymers, silicone-based polymers, and epoxy-based resins.
The amount of EPDM used is preferably 50% by weight or less, more preferably 30% by weight or less, particularly preferably 15% by weight or less, for maintaining the rubber-like properties of the foam.

On the other hand, examples of rubber-based polymers other than the above-mentioned EPDM include α-olefins such as butene-1.
A rubber-based copolymer or ethylene-propylene rubber containing a cyclic or acyclic polyene having a nonconjugated double bond such as dicyclopentadiene or ethylidene norbornene,
Ethylene-propylene terpolymer, silicone rubber,
Fluorine rubber, acrylic rubber, polyurethane rubber, polyamide rubber, natural rubber, polyisobutylene, polyisoprene, chloroprene rubber, butyl rubber, nitrile butyl rubber, styrene / butadiene rubber, styrene / butadiene / styrene rubber, styrene / isoprene / styrene rubber, Examples include styrene / ethylene / butadiene rubber, styrene / ethylene / butylene / styrene rubber, styrene / isoprene / propylene / styrene rubber, and chlorosulfonated polyethylene. The amount of the rubber-based polymer other than EPDM can be the same as in the case of the non-rubber-based polymer.

The foam using the rubber-based foam material according to the present invention can be formed by heating and vulcanizing and foaming the above-mentioned admixture. And vulcanized foam by subjecting the molded body to a heat treatment. In that case, the molded body may be formed into an arbitrary form by an appropriate method, and the form is not particularly limited.

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

In the above, in the formation of a foam having an uneven shape, the unvulcanized sheet is placed on a mold having unevenness and heated, and the mixture forming the unvulcanized sheet is formed on the unevenness of the mold. It is also possible to adopt a method of vulcanizing and foaming by flowing and infiltrating. 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.

Accordingly, the size of the molded article is arbitrary, and can be appropriately determined according to the desired form of the vulcanized foam. In the case of a sheet or the like, the thickness is 100 mm or less,
In particular, 1 μm to 80 mm, especially 10 μm to 50 mm is common.

The above-mentioned vulcanization / foaming treatment can be carried out under appropriate conditions according to the prior art, depending on the vulcanization starting temperature and the foaming temperature of the used vulcanizing agent or foaming agent. General vulcanization foaming temperature is 450 ° C or less, especially 100-350 ° C,
Particularly, it is 120 to 300 ° C. Usually, the vulcanization and foaming treatment softens the admixture and expands the foaming agent to form a foamed structure, and vulcanization proceeds to form a desired vulcanized foam.

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

The expansion ratio (density ratio before and after foaming) of the vulcanized foam to be formed is appropriately determined according to the purpose of use and the like, but is generally 1.1 to 25 times, preferably 1.5 times or more. , Especially 5 to 20 times. The expansion ratio can be controlled by the amount of the above-mentioned foaming agent, the processing time and temperature of vulcanization and foaming, and the like. In addition, by adjusting the expansion ratio, it is possible to control the foaming structure such as independent or continuous vulcanized foam to be obtained, or a mixture thereof.

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, the same applies hereinafter), 1 part of sulfur, 3 parts of a vulcanization accelerator (Noxeller EZ, manufactured by Ouchi Shinko Chemical Co., Ltd.)
Blowing agent (Vinifall AC # LQ, manufactured by Eiwa Chemical Co., Ltd.)
20 parts, foaming aid (Cell Paste K, manufactured by Eiwa Chemical Industry Co., Ltd.)
-5) 5 parts, 200 parts of heavy calcium carbonate, 25 parts of low density polyethylene (Mirason 67, manufactured by Mitsui Chemicals, Inc.), plasticizer oil with a flash point of 270 ° C (Diana Process Oil PW-90, manufactured by Idemitsu Kosan Co., Ltd., paraffin) Oil, kinematic viscosity 4
0 ° C .: 96 mm ² / sec, 100 ° C .: 11 mm ² / sec) 25
Parts, 10 parts of carbon black, 5 parts of zinc oxide (2 types) and 1 part of powdered stearic acid are kneaded with a pressure kneader to obtain an admixture, which is formed by an extruder, and is formed into an unvulcanized sheet having a thickness of 10 mm. Was heated in an oven at 160 ° C. for 30 minutes for vulcanization and foaming treatment to obtain a foamed sheet having a density of 0.12 g / cm ³ .

Example 2 A plasticizer oil having a flash point of 300 ° C. (manufactured by Idemitsu Kosan Co., Ltd., Diana Process Oil PW-380, paraffin oil, kinematic viscosity 40 ° C .: 382 mm ² / sec, 100 ° C.)
A foamed sheet having a density of 0.11 g / cm ³ was obtained in the same manner as in Example 1 except that 30 mm ² / sec) was used.

Example 3 A density of 0.14 g / cm ³ was obtained in the same manner as in Example 1 except that the amount of heavy calcium carbonate used was 300 parts, and 35 parts of Diana process oil PW-380 (plasticizer oil) was used.
Was obtained.

Comparative Example 1 An EPDM having a Mooney viscosity of 42 (manufactured by Mitsui Chemicals, Inc., EPT4045) was used, and the density was 0.35 g / cm. ³
Was obtained.

Comparative Example 2 The same procedure as in Example 1 was repeated except that the amount of the foaming agent was changed to 15 parts and the amount of the heavy calcium carbonate was changed to 50 parts.
A foamed sheet of 13 g / cm ³ was obtained.

Comparative Example 3 Plasticizer oil having a flash point of 170 ° C. (Nippon Oil Co., Ltd., Nisseki Polybutene Oil HV-15, kinematic viscosity 40)
(° C: 655 mm ² / sec, 100 ° C: 31 mm ² / sec), and a foamed sheet having a density of 0.13 g / cm ³ was obtained according to Example 1.

Evaluation Test The rubber foams obtained in the Examples and Comparative Examples were tested for UL94.
The flammability of a test piece of a predetermined thickness of 150 mm in length and 50 mm in width was examined in accordance with the horizontal burning test method for a foamed plastic material according to safety standards, and the HBF corresponding to the flame retardancy was examined. The standard of the HBF level is such that all the test pieces of a predetermined quantity are 125 mm from the mark starting from the ignition starting point.
It is satisfied when the burning speed is 40 mm / min or less up to the mm mark line, or when the combustion ends between the ignition start point and the 125 mm mark line.

The results are shown in the following table. Example Comparative example 1 2 3 1 2 3 3 Burning speed (mm / min) 33 25 21 24 45 52 Loss distance (mm) * 1 95 75 55 80 150 150 Judgment HBF HBF HBF HBF--* 1: Maximum 150 mm

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Takehiro Ui 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 Yutaka Kuryu 1-1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Inside Nitto Denko Corporation (72) Mitsuo Matsumoto 1-1-2 Shimohozumi, Ibaraki City, Osaka Prefecture F-term in Nitto Denko Corporation (reference) 4F074 AA25 AB05 AC02 AC26 AC32 AD09 AG01 AG02 AG10 BA01 BB05 BB09 CA29 CC04Y DA02 DA32 DA33 DA39 DA40 DA57 4J002 AE053 BB151 CC052 CC182 DA006 DA046 DE076 DE106 DE156 DE207 DE37 DJ007 DF007 EF059 EG076 EH029 EH149 EK006 EN006 EQ037 ES006 ES007 ES016 EV249 EV267 EV347 EW049 FB287 FD010 FD023 FD029 FD138 FD142 FD146 FD150 FD320 FD327 GJ02 GL00

Claims (5)

[Claims] 1. Mooney viscosity (ML _{1 + 4} , 100 ° C.)
Is a mixture containing at least 5 to 30 EPDM, a vulcanizing agent, a foaming agent, and calcium carbonate, magnesium carbonate, silicic acid or silicates.
A rubber-based foamed material containing 80 to 400 parts by weight of calcium carbonate, magnesium carbonate, silicic acid or silicates in a total amount of 0 part by weight. 2. The method according to claim 1, wherein the flash point is 200 to 3
50 ° C. plasticizer oil is added in an amount of 1 per 100 parts by weight of EPDM.
A rubber foam material containing 5 to 40 parts by weight. 3. The method according to claim 2, wherein the plasticizer oil is 40%.
30 ~ 500mm at ℃ ²/ Sec, 5-50mm at 100 ° C²/
A rubber-based foam material that exhibits a kinematic viscosity of seconds. 4. The method according to claim 1, wherein at least two kinds of EPDM satisfying the Mooney viscosity are used.
A rubber-based foam material used in an amount of 5 parts by weight and 5 to 95 parts by weight. 5. A rubber foam comprising a vulcanized foam of the rubber foam material according to claim 1.