JP2002146074A - Vulcainzed epdm foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vulcanized EPDM foam having high expansion ratio ad flexibility, excellent in thermal resistance and weather ability by using an EPDM having high diene content. SOLUTION: This vulcanized EPDM foam comprises a vulcanized foam of a rubber constituent comprising a mixture of an EPDM containing 8-20 wt.% diene content and an ethylene/propylene rubber inanamount of 10-50 wt.% based on the EPDM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an EPD having a high diene content.
The present invention relates to an EPDM vulcanized foam made of M and having excellent heat resistance and weather resistance.

[0002]

2. Description of the Related Art Vulcanized foams of the EPDM type have excellent properties.
Based on cushioning, compressibility, etc.
Home appliances as materials such as sealing materials for heat insulation and soundproofing, etc.
Such as indoor goods such as indoors, outdoor goods such as automobiles, and buildings such as houses.
Widely used in various fields, depending on the application
Characteristics such as cushioning and compressibility are adjusted. That
In this case, apply to parts including non-flat parts such as steps
When necessary, a high level
High foam and high flexibility to maintain high performance
Adjusted to vulcanized foam.

Hitherto, in order to obtain a highly foamed and highly flexible vulcanized foam, EPDM having a high diene content has been used. This is based on its high diene content,
This is because the foaming process is easy to control and the foaming ratio is easily set to a high value. However, a vulcanized foam using EPDM having a high diene content has a problem that heat resistance and weather resistance are inferior to those of a vulcanized foam using EPDM having a low diene content.

[0004]

The present invention relates to an EP having a high diene content.
An object of the present invention is to develop an EPDM vulcanized foam having excellent heat resistance and weather resistance, high foaming and high flexibility by using DM.

[0005]

According to the present invention, there is provided a rubber component vulcanized foam comprising a mixture of EPDM having a diene content of 8 to 20% by weight and an ethylene / propylene rubber having 10 to 50% by weight of the EPDM. An object of the present invention is to provide a vulcanized EPDM foam.

[0006]

According to the present invention, EP having a high diene content is provided.
The use of DM makes it easy to control the vulcanization / foaming process, is excellent in step followability, etc. and exhibits high sealing performance even in parts including non-flat parts. It is possible to obtain a vulcanized foam which exhibits heat resistance and weather resistance almost equal to those obtained when a low EPDM is used and is excellent in properties such as cushioning property and compressibility due to rubber properties.

[0007]

DETAILED DESCRIPTION OF THE INVENTION An EPDM vulcanized foam according to the present invention comprises EPDM having a diene content of 8 to 20% by weight and its EP.
It comprises a vulcanized foam of a rubber component consisting of a mixture of DM and 10 to 50% by weight of ethylene / propylene rubber. Such a vulcanized foam can be formed, for example, by a method of heating and vulcanizing and foaming a mixture containing at least the EPDM, ethylene / propylene rubber, vulcanizing agent and foaming agent.

As EPDM, for example, ethylene α-
Olefin-5-ethylidene-2-norbornene copolymerization
A diene content of 8 to 20% by weight
One or more of the above can be used. Above all, go
The Mooney viscosity (M
L _{1 + 4} EPDM of 5 to 30
Can be preferably used. In addition, as the above-mentioned α-olefin
Is generally, but not limited to, propylene.

[0009] Suitable as ethylene-propylene rubber
One or more of these can be used. Such ethylene pu
Use of EPDM with high diene content in combination with propylene rubber
Low diene content while achieving low density and high foaming
Heat resistance and resistance almost equivalent to vulcanized foam using EPDM
Weatherability can be achieved. It is high in diene content
Good timing control of vulcanization and foaming treatment in EPDM
Combined use of ethylene and propylene rubber without impairing performance
To reduce the diene content as a whole rubber component
The effect is realized, and the use of EPDM with low diene content is almost
It is considered that comparable heat resistance is exhibited.

The amount of the ethylene / propylene rubber used is at least 10% by weight, preferably at least 20% by weight, particularly 25 to 50% by weight of the EPDM used in combination. If the amount used is less than 10% by weight, the combined effect is poor and the above-mentioned thinning effect and the like are hardly exhibited. If the amount exceeds 50% by weight, it is difficult to achieve high foaming by the use of EPDM having a high diene content. Tends to be inferior in elongation.

EPDM and ethylene / propylene rubber are
It is preferable to mix them in advance and use the mixture for mixing with other components such as a vulcanizing agent from the viewpoint of the stable development of the above-mentioned properties. In such a case, the mixing state by a kneader such as a Banbury mixer is higher in the EP having a higher diene content than in the mixing state at the molecular level as in the mixing method by solution.
The use of DM is preferred from the viewpoint of achieving the above-mentioned properties such as preservation of good timing controllability of the vulcanization / foaming treatment.

As the vulcanizing agent, one or more appropriate ones capable of vulcanizing or cross-linking EPDM and ethylene / propylene rubber can be used, and are not particularly limited. 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.

From the viewpoint of the physical properties of the obtained vulcanized foam,
Sulfur and organic peroxide with a one-minute half-life temperature of over 160 ° C
The method of using together is preferable. 160 ° C with sulfur
1 minute and half life after vulcanizing EPDM on the low temperature side
Ethylene propylene with organic peroxide at a temperature over 160 ° C
Len rubber can be cross-linked at high temperatures above 160 ° C.
Wear. Vulcanizing only EPDM to produce ethylene propylene
When the system is in an uncrosslinked state, the uncrosslinked portion is likely to be distorted.
In addition, it tends to cause a decrease in compression / restorability.

As the organic peroxide having a one-minute half-life temperature of more than 160 ° C., an appropriate one can be used. Particularly, from the viewpoint of processing efficiency and the like, for example, dicumyl peroxide or dimethyldi (t
Organic peroxides having a one-minute half-life temperature of 200 ° C. or less, particularly 170 to 190 ° C., such as -butylperoxy) hexane and bis (t-butylperoxyisopropyl) benzene, can be preferably used. The amount of the vulcanizing agent can be appropriately determined according to the vulcanizing efficiency based on the type of the vulcanizing agent.
Generally, 0.1 to 10 parts by weight, especially 0.5 to 5 parts by weight, is used per 100 parts by weight of EPDM.

On the other hand, one or more foaming agents may be used.
Any appropriate one can be used, and there is no particular limitation. China
Examples include ammonium carbonate and hydrogen bicarbonate.
Monium, sodium bicarbonate or ammonium nitrite,
Inorganic blowing agents such as sodium borohydride and azides
Is raised. Also, trichloromonofluoromethane and dichloromethane
Alkane fluoride such as chloromonofluoromethane, azo
Bisisobutyronitrile or azodicarboxylic amide (A
DCA), azo such as barium azodicarboxylate
Organic foaming agents, such as organic compounds, are also included.

Further, hydrazine compounds such as paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide) and allylbis (sulfonylhydrazide), ρ-toluylenesulfonyl semicarbazide And semicarbazide compounds such as 4,4'-oxybis (benzenesulfonylsemicarbazide);
Triazole compounds such as morpholyl-1,2,3,4-thiatriazole; N-nitroso such as N, N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide An organic foaming agent such as a system compound is also included.

The foaming agent 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 desired physical properties of the vulcanized foam. Generally, EPDM10
0.1 to 100 parts by weight, especially 0.5 to 5 parts by weight
0 parts by weight, in particular 1 to 30 parts by weight, of a blowing agent is used.

The preparation of the admixture is carried out by mixing the components comprising EPDM, ethylene / propylene rubber, a vulcanizing agent, a foaming agent and the like by an appropriate method such as a method of mixing via a kneader such as a kneader or a mixing roll. Can be performed. At this time, a mixing method in which the temperature is raised to such an extent that vulcanization proceeds is not preferable. Also, as mentioned above, EPD
M and the ethylene / propylene rubber can be separately mixed and the mixture can be subjected to mixing with other compounding components.

In preparing the admixture, an appropriate compounding agent according to the related art is added as necessary for the purpose of adjusting the viscosity and vulcanizability, and adjusting the physical properties such as the strength of the obtained vulcanized foam. be able to. By the way, for the purpose of accelerating vulcanization, for example, guanidines and thiazoles, sulfenamides and tulams, dithiocarbamic acids and xanthogenic acids,
One or more vulcanization accelerators composed of aldehyde ammonias, aldehyde amines, thioureas and the like, and vulcanization acceleration aids can be added. The amount of the vulcanization accelerator used is 0.1 to 1 per 100 parts by weight of EPDM.
0 parts by weight is suitable, but 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 its processability or formability. 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.

Further, the admixture is intended to control moldability and the like.
For example, paraffins such as chlorinated paraffins and waxes
Camphors, naphthenes, aromas, asphalts, flax
Dried oils such as d oil, animal and vegetable oils, petroleum oils and various
Low molecular weight polymers, phthalates and phosphoric acid esters
Ters, stearic acid and its esters, alkyl sulf
One or two consisting of phonates, tackifiers, etc.
More than one softener or plasticizer may be added.
In addition, stearic acid and its esters are used as lubricants, etc.
Are also useful, and are examples of components that can also contain various lubricants.
I can give it. The blending amount of such a softener is EPDM1
15 to 40 parts by weight, especially 20 to 35 weight per 00 parts by weight
Parts by weight are common.

In addition, the admixture includes foaming aids such as urea, salicylic acid and benzoic acid, talc and clay, calcium carbonate and mica powder, zinc white and bentonite, carbon black and silica, alumina and aluminum silicate, Appropriate blending of fillers such as acetylene black and aluminum powder, flame retardants such as magnesium carbonate and aluminum hydroxide, silicic acid and its salts, and other antioxidants, antioxidants, pigments and colorants, and fungicides One or more of the agents can be added as needed. 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.

The formation of the EPDM vulcanized foam according to the present invention can be carried out by heating and vulcanizing and foaming the above-mentioned admixture. And vulcanized foam can be obtained by subjecting the molded body to 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 of the vulcanization and foaming treatment may be the one 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. It may be molded into a predetermined form having irregularities or the like by an appropriate method such as injection molding or press molding.

In the formation of a vulcanized foam having an uneven shape in the above, an unvulcanized sheet is placed on a mold having unevenness and heated to form an admixture for forming the unvulcanized sheet on the unevenness of the mold. And vulcanization and foaming treatment 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. Therefore, the size of the molded body is arbitrary and can be appropriately determined according to the intended form of the vulcanized 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-mentioned vulcanization / foaming treatment can be carried out under appropriate conditions similar to those of the prior art, depending on the vulcanization starting temperature or vulcanization / foaming temperature of the used vulcanizing agent or foaming agent. The general vulcanization and foaming temperature is 450 ° C. or less, especially 100 to 350
° C, especially 120-300 ° 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 this case, 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 pressurizing condition can be according to the conventional.

The expansion ratio (density ratio before and after vulcanization and foaming) of the vulcanized foam to be formed can be appropriately determined according to the purpose of use and the like. Generally, it is 10 times or more, especially 12 to 20 times, from the point that the advantage of high foaming by using EPDM having a high diene content is utilized. 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, it is possible to control the foaming structure such as independent or continuous vulcanized foam obtained by adjusting the expansion ratio, or a mixture thereof.

The vulcanized EPDM foam according to the present invention is preferably used in various conventional applications such as cushioning materials and padding materials, sealing materials for various purposes such as airtightness and waterproofing, heat insulation and soundproofing, and vibration reducing materials. Can be used. Above all, as a vulcanized foam with high foaming and high flexibility by using EPDM with high diene content, as a sealing material etc. applied to parts including non-flat parts such as steps based on its good step followability It can be preferably used.

[0028]

EXAMPLE 1 Ethylene propylene / 5 having a diene content of 9.5% by weight
-70 parts (parts by weight, hereinafter the same) of EPDM composed of an ethylidene-2-norbornene copolymer (Esprene 505A, ethylene content: 50% by weight, manufactured by Sumitomo Chemical Co., Ltd.) and ethylene / propylene rubber (Esprene, manufactured by Sumitomo Chemical Co., Ltd.) 201: 49 parts by weight of ethylene), 30 parts were kneaded with a Banbury mixer for 10 minutes, and 10 parts of carbon black (Asahi Carbon # 50, manufactured by Asahi Carbon Co., Ltd.) and zinc oxide (2 types of zinc oxide, manufactured by Mitsui Kinzoku Kogyo KK) 5 parts, powdered stearic acid (manufactured by NOF Corporation) 2 parts, process oil (manufactured by Idemitsu Kosan Co., Diana Process PW-90) 30
Part, heavy calcium carbonate (Maruo Calcium) 100
And 30 parts of aluminum hydroxide (manufactured by Showa Denko KK, Hijirai H-42), and the mixture was further kneaded for 8 minutes, and then kneaded with a mixing roll to form a sheet.

Next, 0.5 part of sulfur (manufactured by Hosoi Chemical Co., Ltd., differential sulfur) and 100 parts of organic peroxide (Perhexa V-40, manufactured by NOF CORPORATION: 1 minute half-life temperature) 166 ° C.) 3.0 parts, thiazole vulcanization accelerator (Ouchi Shinko Chemical Co., Ltd., Noxeller M) 1.0 part, dithiocarbamate foaming agent (Ouchi Shinko Chemical Co., Ltd., Noxeller EZ) 0.6 Part, dithiocarbamate foaming agent (Ouchi Shinko Chemical Co., Ltd., Noxeller PZ) 0.6 part, ADCA
12 parts (Vinihole AC # LQ, manufactured by Eiwa Chemical Co., Ltd.) and 3 parts of urea (Cell Paste K-5: foaming aid manufactured by Eiwa Chemical Co., Ltd.) were added and kneaded with a mixing roll to obtain an admixture. It is formed with an extruder and has a thickness of 4.5 mm and a width of 150
mm unvulcanized sheet at 100 ° C in a dryer.
After preheating for 0 minutes, the temperature was raised to 160 ° C. over 15 minutes, heated at that temperature for 15 minutes to perform vulcanization and foaming treatment, and then heated at 180 ° C. for 70 minutes to obtain a vulcanized foam sheet having an expansion ratio of 12 times. Was.

Example 2 EPDM and ethylene / propylene rubber were used in a proportion of 50
Vulcanized foamed sheet having an expansion ratio of 12 times according to Example 1 except that the same amount was used for each part, the amount of sulfur used was 1.0 part, and the amount of organic peroxide used was 5.0 parts. I got

COMPARATIVE EXAMPLE 1 EPDM was used in an amount of 100 parts without ethylene-propylene rubber, and carbon black 10 parts, zinc oxide 5 parts, powdered stearic acid 2 parts, process oil 3
0 parts, 100 parts of heavy calcium carbonate, and 30 parts of aluminum hydroxide were added, and the mixture was kneaded with a Banbury mixer for 10 minutes, then kneaded with a mixing roll to form a sheet, and 100 parts of the mixture was mixed with 0.5 part of sulfur and thiazole 0.5 parts of a vulcanization accelerator, 0.6 parts of a dithiocarbamate foaming agent,
12 parts of ADCA and 3 parts of urea were added and kneaded with a mixing roll to obtain a mixture, which was formed into an unvulcanized sheet by an extruder. I got a sheet.

Comparative Example 2 The amount of EPDM composed of an ethylene / propylene / 5-ethylidene-2-norbornene copolymer having a diene content of 4% by weight (Esprene 501A manufactured by Sumitomo Chemical Co., Ltd .; ethylene content of 52% by weight) was determined. Ethylene propylene rubber was not blended as 100 parts, and carbon black 10
Parts, 5 parts of zinc oxide, 2 parts of powdered stearic acid, 30 parts of process oil, 100 parts of heavy calcium carbonate, and 30 parts of aluminum hydroxide.
After kneading for a minute, scour with a mixing roll to make a sheet,
1.5 parts of sulfur, 1.0 part of a thiazole vulcanization accelerator, and 1.0 part of a dithiocarbamate foaming agent were added to 100 parts of the mixture.
0 parts, 12 parts of ADCA and 3 parts of urea were added and kneaded with a mixing roll to obtain a mixture, which was formed into an unvulcanized sheet by an extruder according to Example 1 and then dried in a drier.
After preheating at 00 ° C for 25 minutes, the temperature was raised to 160 ° C over 15 minutes, and then heated at that temperature for 15 minutes to perform vulcanization and foaming treatment, and then heated at 180 ° C for 70 minutes to produce a vulcanized foam having an expansion ratio of 10 times. I got a sheet.

Evaluation Test The vulcanized foam sheets obtained in Examples and Comparative Examples were examined for weather resistance (Daipla Metal Weather, manufactured by Dainippon Plastics Co., Ltd.). In the test, the sheet was sliced to a thickness of 10 mm, punched out with a dumbbell No. 1 for a tensile test according to JIS K6251, and the sample was subjected to light energy of 68.0.
8 hours and 30 hours at 83 ° C. and 50% RH at mW / cm ² .
Exposure was repeated four times with one cycle of 4 hours at 98 ° C. and 98% RH, followed by a tensile test in accordance with JIS K6251, and the residual elongation was determined from the elongation at that time by the following formula. Residual elongation (%) = (elongation after exposure / elongation before exposure) × 1
00

The vulcanized foamed sheets obtained in the Examples and Comparative Examples were examined for thermal compression set using a tester for a compression set test according to JIS K6262. The test is
A sample having a diameter of 29 mm and a thickness of 10 ± 0.15 mm was placed between the parallel metal plates, and the parallel metal plates were bolted and fixed via a 5 mm-thick spacer (sample compression ratio 50%).
After being left in a constant temperature bath at 0 ° C. for 22 hours, the sample was taken out from between the parallel metal plates and allowed to cool at room temperature for 30 minutes, and the thickness of the sample was measured with a thickness gauge according to JIS K 6262. The thermal compression set (CS) was calculated by the following equation. CS (%) = (Thickness before test−Thickness after test) / (Thickness before test−Thickness of spacer) × 100

The results are shown in the following table. Example 1 Example 2 Comparative Example 1 Comparative Example 2 Expansion ratio (times) 12 12 12 10 Elongation before exposure (%) 303 253 343 152 152 Residual elongation (%) 68 82 48 86 CS (%) 21 25 45 11

From the table, it can be seen that Examples 1 and 2 in which ethylene and propylene rubbers were used in combination had excellent residual elongation after exposure to a weather meter and low thermal compression set as compared with Comparative Example 1 in which no ethylene / propylene rubber was used. . From this, it can be seen that in the examples, weather resistance and heat resistance almost comparable to Comparative Example 2 having a low diene content were achieved, and a higher expansion ratio was achieved than Comparative Example 2.

Continued on the front page F-term (reference) 4F074 AA00 AA25 AA98 AC02 AC03 AC20 AC26 AD08 AD09 AD13 AD14 AD19 BA13 BA20 BA29 BB02 BB04 BB05 BB29 CA29 CC04Y CC06W CC06Y CC22X DA33 DA39 DA40 4J002 BB15W BB15X DA060 EK 030

Claims (2)

[Claims] 1. An EPDM having a diene content of 8 to 20% by weight.
An EPDM vulcanized foam comprising a vulcanized foam of a rubber component, comprising a mixture of ethylene-propylene rubber and 10 to 50% by weight of the EPDM. 2. The method according to claim 1, wherein the EPDM is an ethylene / α-olefin / 5-ethylidene-2-norbornene copolymer, and is added with sulfur and an organic peroxide having a one-minute half-life temperature of more than 160 ° C. An EPDM vulcanized foam which has been subjected to sulfuric treatment.