JP4150467B2 - Rubber-based foam material and foamed body thereof - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rubber-based foam material capable of forming an EPDM-based foam exhibiting combustion retardance.
[0002]
[Prior art]
EPDM foam is based on its superior cushioning properties and compressibility, such as cushioning materials and pad materials, sealing materials such as airtight and water-stopping materials, heat insulating materials and soundproofing materials, etc. It is widely used in various fields such as outdoor products and buildings such as houses, and characteristics such as cushioning and compressibility are adjusted according to the application.
[0003]
However, conventionally, regarding the flame retardancy of the foam, an olefin polymer such as EPDM has a high combustion energy, so that a flame retardant such as a metal hydroxide, a phosphorus compound, a halide, or a silicone compound is used. A method of blending has been exclusively adopted. For this reason, there is a difficulty that it is difficult to balance the difficulty of combustion of the product with other performances, such as that only the flame retardancy becomes excessive quality.
[0004]
[Technical Problem of the Invention]
An object of the present invention is to develop a rubber-based foam material capable of forming an EPDM-based foam that achieves a retarded combustion without using a generally used flame retardant and has an excellent balance of various performances.
[0005]
[Means for solving problems]
The present invention relates to EPDM having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 to 30, a vulcanizing agent, a foaming agent, a plasticizer oil having a flash point of 200 to 350 ° C., and calcium carbonate, magnesium carbonate, silicic acid or silica. A mixture comprising at least an acid salt as a component , and 80 parts by weight of the total amount of calcium carbonate, magnesium carbonate, silicic acid or silicates per 100 parts by weight of the EPDM , and 15 to 15 parts of the plasticizer oil. The present invention provides a rubber foam material containing 40 parts by weight .
[0006]
【The invention's effect】
By using the above-mentioned EPDM, it becomes possible to mix a large amount of fillers other than the flame retardant that can control the combustion characteristics, and the cushioning property, compressibility, etc. while preserving the rubber physical properties of the EPDM foam well. performance can be controlled, and be able to have a flame retardant without using a flame retardant, it is possible to improve the flame retardancy by a high flash point plasticizer oils.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The rubber-based foam material according to the present invention comprises an EPDM having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 to 30, a vulcanizing agent, a foaming agent, a plasticizer oil having a flash point of 200 to 350 ° C. , calcium carbonate and magnesium carbonate. , A mixture containing at least a component of silicic acid or silicate , and the total amount of calcium carbonate, magnesium carbonate, silicic acid or silicate is 80 to 400 parts by weight per 100 parts by weight of the EPDM , and the plastic It contains 15 to 40 parts by weight of agent oil .
[0008]
As EPDM, one having Mooney viscosity (ML _{1 + 4} , 100 ° C., hereinafter the same) 5 to 30 can be used alone or in combination. When the viscosity is outside the above range, it is difficult to adjust performance such as combustion retardancy and compressibility while leaving rubber properties. The preferred Mooney viscosity of EPDM is 8-25. When two or more kinds of EPDM satisfying the Mooney viscosity are used, any one of them is used at a ratio of 95 to 5 parts by weight, and the others are used at a ratio of 5 to 95 parts by weight, from the viewpoint of the operability for adjusting the performance. It is preferable.
[0009]
As the vulcanizing agent, one or more suitable 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-quinonedioxime and P, P'-dibenzoylquinonedioxime. Examples thereof include oximes such as nitroso compounds such as P-dinitrosobenzidine, resins such as alkylphenol / formaldehyde resins and melamine / formaldehyde condensates, and ammonium salts such as ammonium benzoate.
[0010]
Sulfur and sulfur compounds, particularly sulfur, can be preferably used from the viewpoint of physical properties such as vulcanizability and foaming durability of the obtained foam. The amount of the vulcanizing agent used can be appropriately determined according to the vulcanization efficiency based on the type. Incidentally, in the case of a sulfur type, usually 0.1 to 10 parts by weight, especially 0.5 to 5 parts by weight are used per 100 parts by weight of EPDM.
[0011]
Moreover, 1 type, or 2 or more types of suitable foaming agents can be used, and there is no particular limitation. Examples thereof include inorganic foaming agents such as ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride and azides.
[0012]
Also, fluorinated alkanes such as trichloromonofluoromethane and dichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, azodicarboxylic acid amide and barium azodicarboxylate, paratoluenesulfonyl hydrazide and diphenylsulfone-3,3 Organic foaming agents such as hydrazine-based compounds such as' -disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide), and allylbis (sulfonylhydrazide) are also included.
[0013]
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, N, N′— Organic foaming agents such as dinitrosopentamethylenetetramine and N-nitroso compounds such as N, N′-dimethyl-N, N′-dinitrosotephthalamide are also included. The foaming agent used may be heat-expandable fine particles in which a heat-expandable substance is enclosed in microcapsules. The thermally expandable fine particles include commercially available products such as microspheres (trade name, manufactured by Matsumoto Yushi Co., Ltd.).
[0014]
The amount of the foaming agent used can be appropriately determined according to the physical properties of the target foam. In general, 0.1 to 100 parts by weight, especially 0.5 to 50 parts by weight, especially 1 to 30 parts by weight, of foaming agent is used per 100 parts by weight of EPDM.
[0015]
The rubber-based foam material is blended with at least one or more of calcium carbonate, magnesium carbonate, silicic acid or silicates in order to impart combustion retardancy. The blending amount is 80 to 400 parts by weight based on the total amount of calcium carbonate, magnesium carbonate, silicic acid or silicate per 100 parts by weight of EPDM.
[0016]
If the blending amount is less than 80 parts by weight, the effect of retarding combustion is poor, and if it exceeds 400 parts by weight, it is difficult to adjust the performance of the foam obtained by reducing the rubbery properties. The preferred blending amount of calcium carbonate and the like is 380 parts by weight or less, especially 350 parts by weight or less, particularly 100 to 300 parts by weight, from the viewpoint of the effect of imparting such a flame retardancy and the ability to adjust foam performance.
[0017]
The admixture is prepared by blending at least a blending component consisting of EPDM, a vulcanizing agent, a foaming agent , a plasticizer oil having a flash point of 200 to 350 ° C. and the above calcium carbonate, through a kneader such as a kneader or a mixing roll. Can be carried out by mixing by an appropriate method such as a mixing method. At that time, a mixing method in which the temperature rises to such an extent that vulcanization proceeds is not preferable.
[0018]
In preparing the admixture described above, an appropriate compounding agent according to the prior art can be added for the purpose of adjusting viscosity and vulcanizability, and adjusting physical properties such as strength of the resulting foam. Incidentally, for the purpose of promoting vulcanization, for example, guanidines and thiazoles, sulfenamides and turums, dithiocarbamic acids and xanthogenic acids, aldehyde ammonias, aldehyde amines, thioureas, etc. Vulcanization accelerators, and further vulcanization acceleration assistants 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 EPDM, but is not limited thereto.
[0019]
The admixture contains organic acids such as phthalic anhydride, benzoic acid, and salicylic acid, and amines such as N-nitroso-diphenylamine and N-nitroso-phenyl-β-naphthylamine for the purpose of controlling processability and moldability. One or two or more kinds of vulcanization retarders composed of a kind or the like can be blended to delay the vulcanization, contrary to the above vulcanization accelerator.
[0020]
For admixtures, for example, paraffins such as chlorinated paraffins and waxes, naphthenes, aromas, asphalts, dry oils such as linseed oil, animal and vegetable oils, petroleum One or more softeners or plastics consisting of oils, various low-volume polymers, phthalates and phosphates, stearic acid and esters thereof, alkyl sulfonates and tackifiers An agent can also be added. Note that stearic acid and its esters are useful as a lubricant and the like, and therefore, examples of components in which various lubricants can be blended.
[0021]
The like that utilize the flame retardant is in the preparation of the blend, flash point 200 to 350 ° C., preferably used are plasticizers consisting of oils of 220-330 ° C., moldability further improves and the resulting foam when considering the maintenance and the like of the rubber characteristics of, 30~500mm ² / s at 40 ° C., especially 60~450mm ² / sec, 5 to 50 mm ² / s at 100 ° C., especially 10 to 40 mm ² / Those showing a kinematic viscosity in seconds are particularly preferred. The amount of such points by Rika plasticizer oil is 15 to 40 parts by weight per EPDM100 parts by weight, preferably 20 to 35 parts by weight.
[0022]
In addition, the admixtures include foaming aids such as urea, salicylic acid and benzoic acid, talc, clay, mica powder, zinc white, bentonite, carbon black and silica, alumina, aluminum silicate, acetylene black and aluminum powder. One kind or two or more kinds of suitable compounding agents excluding conventional flame retardants such as fillers, antioxidants, antioxidants, pigments, colorants and fungicides can be added as necessary. The zinc white is also useful as a stabilizer, and carbon black is useful as a reinforcing agent. Therefore, examples of components in which various stabilizers and reinforcing agents can be blended are listed.
[0023]
Further, in the admixture, one or more kinds of non-rubber polymers and rubber polymers other than EPDM can be blended for the purpose of adjusting physical properties such as strength of the obtained foam. Any suitable non-rubber polymer or rubber polymer can be used without any particular limitation.
[0024]
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 polyester, chlorine. Polyethylene, urethane polymer, styrene polymer, silicone polymer, epoxy resin and the like. The amount used is preferably not more than 50% by weight of EPDM, more preferably not more than 30% by weight, especially not more than 15% by weight, from the viewpoint of maintaining the rubbery properties of the foam.
[0025]
On the other hand, examples of rubber-based polymers other than the above-mentioned EPDM include rubbers containing as a component a cyclic or non-cyclic polyene having a non-conjugated double bond such as α-olefin dicyclopentadiene such as butene-1 or ethylidene norbornene. Copolymer, ethylene / propylene rubber, ethylene / propylene terpolymer and silicone rubber, fluorine rubber and acrylic rubber, polyurethane rubber and polyamide rubber, natural rubber and polyisobutylene, polyisoprene and chloroprene rubber, butyl rubber and 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 Beam, such as chlorosulfonated polyethylene. The blending amount of the rubber-based polymer other than EPDM can be based on the non-rubber-based polymer.
[0026]
Formation of the foam using the rubber-based foam material according to the present invention can be performed by heating the above-mentioned admixture and subjecting it to vulcanization and foaming treatment. It is also possible to form a vulcanized foam by heat-treating the molded body. In that case, the molded body may be molded into an arbitrary form by an appropriate method, and the form is not particularly limited.
[0027]
Therefore, the object of vulcanization and foaming treatment may be a mixture obtained by molding the admixture into a sheet or other form by an appropriate method such as a mixing roll, a calender roll, or extrusion molding, or through a predetermined mold. Further, it may be formed into a predetermined form having irregularities by an appropriate method such as injection molding or press molding.
[0028]
In the above, in the formation of a foam having an uneven shape, an unvulcanized sheet is placed on a mold having unevenness and heated, and the mixture forming the unvulcanized sheet flows into the unevenness of the mold to flow in A method of vulcanizing and foaming can also be adopted. Such a method has an advantage that the concavo-convex shape can be accurately formed even in the case of a mold having a complex and deep concavo-convex structure.
[0029]
Therefore, the size of the molded body is arbitrary, and can be appropriately determined according to the form of the target vulcanized foam. In the case of a sheet or the like, the thickness is generally 100 mm or less, in particular, 1 μm to 80 mm, particularly 10 μm to 50 mm.
[0030]
The vulcanization foaming treatment described above can be performed under appropriate conditions according to the prior art depending on the vulcanization start temperature, foaming temperature, and the like using the vulcanizing agent and the foaming agent used. A typical vulcanization foaming temperature is 450 ° C. or lower, especially 100 to 350 ° C., particularly 120 to 300 ° C. In general, the vulcanization and foaming treatment softens the admixture and expands the foaming agent to form a foam structure, and vulcanization proceeds to form the desired vulcanized foam.
[0031]
In the above, the foaming treatment and the vulcanization treatment can be performed under different temperature conditions, and appropriate treatment conditions can be taken. The vulcanization foaming treatment can also be performed under pressure for the purpose of adjusting the foaming ratio. The pressurizing condition can be based on the conventional one.
[0032]
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, etc., but is generally 1.1 to 25 times, especially 1.5 times or more, especially 5 -20 times. The expansion ratio can be controlled by the blending amount of the foaming agent described above, the processing time and temperature of vulcanization foaming, and the like. In addition, by adjusting the foaming ratio, the foamed structure of the obtained vulcanized foam can be controlled independently, continuously, or a mixture thereof.
[0033]
The rubber-based foam according to the present invention is preferably used in various conventional applications such as cushion materials, pad materials, sealing materials for various purposes such as airtightness and waterproofing, heat insulating materials, vibration reducing materials such as soundproofing and vibration damping. Can be used.
[0034]
【Example】
Example 1
100 parts of EPDM (Mitsui Chemicals, EPT4021) with Mooney viscosity 23, 1 part of sulfur, 1 part of sulfur, 3 parts of vulcanization accelerator (Ouchi Shinsei Chemical Co., Noxeller EZ), foaming agent (Eiwa Chemicals) Industrial parts, VINIFOL AC # LQ 20 parts, foaming aid (manufactured by Eiwa Chemical Industries, Cell Paste K-5), heavy calcium carbonate 200 parts, low density polyethylene (Mitsui Chemicals, Mirason 67) 25 parts, plasticizer oil with a flash point of 270 ° C. (Idemitsu Kosan Co., Ltd., Diana Process Oil PW-90, paraffin oil, kinematic viscosity 40 ° C .: 96 mm ² / sec, 100 ° C .: 11 mm ² / sec) 25 parts, carbon black 10 parts, 5 parts of zinc oxide (2 types) and 1 part of powdered stearic acid were kneaded with a pressure kneader to obtain a blend, which was molded with an extruder to obtain a 10 mm thick unvulcanized sheet, 1 It was heated in an oven at 60 ° C. for 30 minutes and vulcanized and foamed to obtain a foamed sheet having a density of 0.12 g / cm ³ .
[0035]
Example 2
As a plasticizer oil, those flash point 300 ° C. (manufactured by Idemitsu Kosan Co., Ltd., Diana Process Oil PW-380, paraffin oil, kinematic viscosity 40 ℃: 382mm ² / s, 100 ℃: 30mm ² / s) but using the A foamed sheet having a density of 0.11 g / cm ³ was obtained according to Example 1.
[0036]
Example 3
A foamed sheet having 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. .
[0037]
Comparative Example 1
A foamed sheet having a density of 0.35 g / cm ³ was obtained in the same manner as in Example 1 except that an EPDM having a Mooney viscosity of 42 (EPT4045 manufactured by Mitsui Chemicals, Inc.) was used and the amount of foaming agent used was 15 parts. It was.
[0038]
Comparative Example 2
A foamed sheet having a density of 0.13 g / cm ³ was obtained in the same manner as in Example 1 except that the amount of foaming agent used was 15 parts and the amount of heavy calcium carbonate used was 50 parts.
[0039]
Comparative Example 3
Flashpoint those 170 ° C. as plasticizer oils other embodiments using the (Nippon Oil Co., Nisseki polybutene oils HV-15, kinematic viscosity 40 ℃:: 655mm ² / s, 100 ° C. 31 mm ² / sec) 1, a foamed sheet having a density of 0.13 g / cm ³ was obtained.
[0040]
For the rubber-based foams obtained in the evaluation test examples and comparative examples, the flammability of a test piece having a predetermined thickness of 150 mm in length and 50 mm in width is examined in accordance with the horizontal combustion test method for foamed plastic materials according to UL94 safety standards. At the same time, HBF corresponding to combustion retardancy was examined. The standard for the HBF level is that when a predetermined number of all specimens are between the 25mm mark and the 125mm mark from the ignition start point and the combustion speed is 40mm / min or less, or the combustion is between the ignition start point and the 125mm mark. Satisfied when ending with.
[0041]
The results are shown in the following table.

Claims (4)

EPDM having a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 5 to 30, a vulcanizing agent, a foaming agent, a plasticizer oil having a flash point of 200 to 350 ° C., and calcium carbonate, magnesium carbonate, silicic acid or silicates. It is composed of an admixture containing at least components, and contains 100 to 100 parts by weight of EPDM, 80 to 400 parts by weight of the total amount of calcium carbonate, magnesium carbonate, silicic acid or silicates , and 15 to 40 parts by weight of the plasticizer oil A rubber-based foam material characterized by: In claim 1, a rubber-based foamed material shows a kinematic viscosity of 5 to 50 mm ² / sec at plasticizer oil is 40 ℃ 30~500mm ² / sec, at 100 ° C.. The rubber-based foamed material according to claim 1 or 2 , wherein two or more kinds of EPDM satisfying the Mooney viscosity are used in a ratio of 95 to 5 parts by weight, and 5 to 95 parts by weight. Rubber foam, characterized in that it consists of vulcanized foam rubber-based foam material according to one of claims 1 to 3.