JP2002332409A - Resin composition for vulcanization mold and method for peroxide vulcanization of rubber-like elastic body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition having excellent durability used as a surface of an elastic body in a vulcanization molding when carrying out peroxide vulcanization of the elastic body, and a method for the peroxide vulcanization of the elastic body using the vulcanization mold. SOLUTION: This resin composition for the vulcanization mold comprises a thermoplastic resin having >=200 deg.C melting temperature and an amine antioxidant in an amount of 0.4-5.5 pts.wt. based on 100 pts.wt. of the thermoplastic resin. The method for the peroxide vulcanization of the elastic body comprises installing the vulcanization mold using the resin composition on the surface of the elastic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vulcanization mold resin composition and a method for peroxide vulcanizing rubber-like elastic materials. More specifically, the present invention provides a highly durable resin composition used for a vulcanization mold provided on the surface of a rubber-like elastic body when peroxide vulcanizing the rubber-like elastic body, and providing a vulcanization mold on the surface to provide a rubber-like elastic body. The present invention relates to a vulcanization method using the above-mentioned resin composition having excellent durability as a vulcanization mold when vulcanizing a body with peroxide.

[0002]

2. Description of the Related Art As a method for manufacturing rubber pipes, tubes, hoses, and the like, generally, an inner pipe rubber layer, a reinforcing member layer, and an outer pipe rubber layer are sequentially provided around a mandrel, and the outside thereof is coated with a coating material. After the coating, a vulcanization treatment is performed by applying heat and pressure, and then the coating is peeled off and the mandrel is pulled out. The coating is provided for vulcanization. Conventionally, metallic lead has been used as a coating material. However, due to environmental problems, in recent years, a heat deformation temperature is high, and heat is excellent in releasing property. Polymethylpentene, a plastic resin, is generally used. The coating is referred to as a vulcanization mold in the present invention. By the way, in the case of rubber pipes, tubes, hoses, etc., in order to impart weather resistance, the outer tube rubber layer does not have a double bond in the molecule or has a Ethylene-propylene rubber (EPR) or ethylene-propylene-diene rubber (EPDM) having a low content is often used. Since vulcanization of these rubbers is usually performed by peroxide vulcanization, the polymethylpentene chains covering the outer tube rubber layer are cut by active free radicals generated from peroxide used as a vulcanizing agent. This leads to an undesirable situation. As a result, when repeatedly reused as a vulcanized mold, it becomes brittle due to its cutting action,
With a small number of reuses, the rubber cannot withstand deformation due to thermal expansion of the rubber at the vulcanization temperature, causing cracks in the mold and making it impossible to play a role as a mold. Was.

[0003]

SUMMARY OF THE INVENTION The present invention provides a highly durable resin composition used in a vulcanization mold provided on the surface of a rubber-like elastic body when peroxide vulcanizing the rubber-like elastic body under such circumstances. An object of the present invention is to provide a vulcanization method using a resin composition having excellent durability as a vulcanization mold when a vulcanization mold is provided on a surface and a rubber-like elastic body is peroxide-vulcanized.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and have found that an amine-based antioxidant is blended in a specific ratio with a thermoplastic resin having a high heat distortion temperature. It has been found that such a resin composition can achieve the object. The present invention has been completed based on such findings. That is, the present invention relates to (1) a resin composition used for a vulcanization mold provided on the surface of a rubber-like elastic body when performing peroxide vulcanization, and having a melting temperature of 2
(2) a vulcanization mold resin composition comprising: a thermoplastic resin having a temperature of 00 ° C or higher; and an amine-based antioxidant in an amount of 0.4 to 5.5 parts by weight per 100 parts by weight thereof.
A method for peroxide vulcanizing a rubber-like elastic body, comprising providing a vulcanization mold on the surface and peroxide vulcanizing the rubber-like elastic body, wherein the resin composition is used as the vulcanization mold. It is.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition for a vulcanization mold of the present invention is a resin composition used for a vulcanization mold provided on the surface of a rubber-like elastic body when peroxide vulcanization is performed. In the resin composition, a thermoplastic resin having a melting temperature of 200 ° C. or more is used. This melting temperature is 200 ° C
If it is less than the above, there is a possibility of undergoing thermal deformation during vulcanization. Further, the thermoplastic resin is excellent in mold releasability, and preferably has good moldability, and such a thermoplastic resin is not particularly limited as long as it has the above properties, For example, a mixture of polymethylpentene and another thermoplastic resin containing polymethylpentene as a main component can be preferably mentioned. The properties of currently commercially available polymethylpentene are:
Melt flow rate measured under the condition of 9.03 N [MF
R] (ASTM D1238) 22-180 g / 10
And the mechanical properties (ASTM D638)
Elongation at break at 20 ° C. at a pulling speed of 5 mm / min at 23 ° C.
120%, tensile strength at break 15.7-17.2 N / mm
^{2. The} yield point stress is 14.7 to 23.0 N / mm ² .

On the other hand, various amine antioxidants can be used, but secondary aromatic amines are preferred. Here, examples of the secondary aromatic amine include naphthylamines such as phenyl-α-naphthylamine and phenyl-β-naphthylamine, p- (p-toluenesulfonylamide) -diphenylamine, and 4,4′-bis (α, α -Dimethylbenzyl) diphenylamine,
Diphenylamines such as 4,4'-dioctyldiphenylamine, octylated diphenylamine, alkylated diphenylamine and diphenylamine derivatives, N, N '
Diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N,
N'-di-2-naphthyl-p-phenylenediamine, N
-Cyclohexyl-N'-phenyl-p-phenylenediamine, N-phenyl-N '-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, N, N'-bis (1-methylheptyl)- p-phenylenediamine, N, N'-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N'-bis (1-ethyl-3-methylpentyl) -p-phenylenediamine, N- ( 1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, phenylhexyl-
p-phenylenediamines such as p-phenylenediamine and phenyloctyl-p-phenylenediamine; and the like. One of these amine antioxidants may be used alone, or two or more thereof may be used in combination. This amine-based antioxidant is used before active free radicals generated from peroxide during peroxide vulcanization extract hydrogen bonded to tertiary carbon in a thermoplastic resin such as polymethylpentene and cause molecular cleavage. It reacts with active free radicals and has the effect of preventing molecular cleavage.

[0007] In the resin composition of the present invention, the amine-based antioxidant is blended in an amount of 0.4 to 5.5 parts by weight based on 100 parts by weight of the thermoplastic resin. If the amount is less than 0.4 part by weight, the effect of increasing the number of repeated use of the vulcanization mold, ie, the effect of improving the durability, is hardly exhibited. On the other hand, if it exceeds 5.5 parts by weight, vulcanization is inhibited near the interface where the peroxide vulcanized rubber and the thermoplastic resin come into contact, which causes an increase in surface tackiness. In addition, since the amine-based antioxidant is consumed as the resin composition is repeatedly used as a vulcanization mold, it is newly added every one or more times of repeated use so as to fall within the specified range. Is preferred. In the resin composition of the present invention, as long as the object of the present invention is not impaired, various additives such as an antioxidant other than an amine-based antioxidant, a thermal deterioration inhibitor, a lubricant, a release agent, Agents and the like can be blended.

Next, a method for peroxide vulcanizing a rubber-like elastic material according to the present invention will be described. In the vulcanization method of the present invention, a vulcanization mold made of the above-described resin composition is provided on the surface, and the rubber-like elastic body is peroxide-vulcanized. here,
The rubber-like elastic material to be peroxide-vulcanized is not particularly limited as long as it can be peroxide-vulcanized, and various materials can be used. Examples of such a rubbery elastic body include ethylene-propylene rubber (EPR),
Ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), hydrogenated NBR, acrylic rubber (ACM), chlorosulfonated polyethylene rubber (CSM), fluorine rubber, ethylene-methyl acrylate copolymer, Examples include natural rubber, silicone rubber, epichlorohydrin rubber, and the like. These may be used alone or in a combination of two or more.

On the other hand, there is no particular limitation on the peroxide used for peroxide vulcanization, and peroxides conventionally used for peroxide vulcanization of rubbery elastomers, such as dialkyl peroxides, peroxyesters and peroxyketals, can be used. Any of them can be selected and used, but dialkyl peroxide is particularly preferred. Here, examples of the dialkyl peroxide include di-tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, 2,
5-dimethyl-2,5-di-tert-butyl peroxide hexane, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 2,
5-dimethyl-2,5-di-tert-butylperoxyhexyne-3 and the like. In the present invention, in the peroxide vulcanization of the rubber-like elastic body, the peroxide is preferably used in an amount of 1 to 20 parts by weight, more preferably 3 to 100 parts by weight, based on 100 parts by weight of the rubber-like elastic body.
10 to 10 parts by weight, and if necessary, an unvulcanized composition containing a filler, a processing aid, an antioxidant, a vulcanization accelerator, a vulcanization acceleration aid, and the like is formed into a desired shape. After that, the above-described vulcanization mold is provided on the surface, and vulcanization is performed by heat treatment.

The vulcanization conditions vary depending on the type of the rubber-like elastic material and the type of peroxide.
At a temperature of ~ 190 ° C for about 10 to 180 minutes, preferably at a temperature of 130 to 180 ° C for 15 to 12 minutes.
The vulcanization is performed by performing a heat treatment for about 0 minutes. In the method of the present invention, the above-described resin composition of the present invention having excellent durability is used for the vulcanization mold provided on the surface of the rubber-like elastic body in peroxide vulcanization. Mold deterioration is suppressed,
The number of times of repeated use can be extended. Such a peroxide vulcanization method of the present invention is suitably used for producing, for example, rubber pipes, tubes, hoses and the like.

[0011]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 to 3 First, an isobutylene / bromo-p-methylstyrene copolymer (registered trademark “MDX89-1”, manufactured by Exxon Co.) was used as a composition for the inner tube rubber layer. Parts by weight, 65 parts by weight of FEF carbon black, 0.5 parts by weight of stearic acid, 5 parts by weight of paraffin oil, 5 parts by weight of zinc white, 1 part by weight of a vulcanization accelerator (tetramethylthiuram disulfide) and 0.5 parts by weight of sulfur As a composition for an intermediate rubber layer, 80 parts by weight of an isobutylene / bromo-p-methylstyrene copolymer (described above), 20 parts by weight of EPDM,
EF carbon black 65 parts by weight, stearic acid 0.5
Parts by weight, paraffin oil 5 parts by weight, zinc white 1 part by weight,
A composition containing 1 part by weight of a vulcanization accelerator (tetramethylthiuram disulfide) and 0.5 part by weight of sulfur was used as an outer rubber composition, 100 parts by weight of EPDM, 80 parts by weight of FEF carbon black, and 1 part by weight of stearic acid. Parts, 15 parts by weight of paraffin oil, atactic polypropylene (manufactured by Chisso Petrochemical Co., Ltd., registered trademark "Vistax M")
30 parts by weight, zinc white 5 parts by weight, dialkyl peroxide [registered trademark "Park Mill D-4" manufactured by NOF Corporation
0 "] A composition containing 5 parts by weight and 12 parts by weight of bismaleimide was prepared.

Next, a 6-mm mandrel is placed on a mandrel having a diameter of 13 mm.
After extruding the inner resin composition blended with nylon and polyolefin and coating it with a thickness of about 0.2 mm,
The composition for the inner tube rubber layer was extruded thereon, and the thickness was 1.2 mm.
Was provided with an inner tube rubber layer. Next, 30
Twenty-four 00 denier polyester reinforcing yarns are aligned and spirally wound, and then the composition for the intermediate rubber layer is extruded to provide an intermediate rubber layer having a thickness of 0.3 mm. Were aligned and wound spirally. Subsequently, the composition for the outer covering rubber was extruded, and a 1.3 mm thick outer covering rubber layer was provided. After that, the resin compositions shown in Tables 1 and 2 were melt-extruded thereon, and were extruded to a thickness of 2 mm. A sulfur mold was provided. Next, this product was vulcanized at 150 ° C. for 60 minutes in a hot air oven, the vulcanization mold was peeled off immediately after vulcanization, and the mandrel was pulled out to produce a hose having the structure shown in FIG. In FIG. 1, reference numeral 1 denotes an inner surface resin, 2 denotes an inner tube rubber layer, 3 denotes an inner tube layer, 4 denotes a reinforcing yarn and an intermediate rubber layer, and 5 denotes a jacket rubber.

The peeled mold was pelletized by a pulverizer and used repeatedly. However, in the case of the fifth embodiment,
After repeated use up to 10 times, at the time of the 11th use, add 1 part by weight of an amine-based antioxidant, which is an amount corresponding to the amount consumed up to the 10th time, and make a total of 3 parts by weight for 20 times In the case of Example 6, it was repeated up to 20 times in the same manner as in Example 5, and then 2
At the time of the first use, 1 part by weight of the amine-based antioxidant corresponding to the amount consumed at the 11th to 20th times was added, and the mixture was repeatedly used up to 30 times as a total of 3 parts by weight.

The following evaluation was performed on this vulcanization method.
The results are shown in Tables 1 and 2. <Evaluation> (1) Influence on rubber In order to determine the tackiness of the outer rubber caused by the vulcanization inhibition by the amine antioxidant in the resin composition, the outer cover was removed when the vulcanization mold was peeled off. The presence or absence of scratches on the rubber surface was visually observed, and the degree of influence on the rubber was evaluated based on the following criteria. C: Scratches were observed and the sample could not be put to practical use. A: Other than the above. (2) Number of repeated use of the resin composition The number of repetitions of the resin composition was evaluated according to the following criteria. ：: When used for vulcanization more than 10 times, ×: In cases other than the above,

[0016]

[Table 1]

[0017]

[Table 2]

1) Polymethylpentene MX002: registered trademark “TPXMX002” manufactured by Mitsui Chemicals, Inc. 2) Polymethylpentene MX004: Mitsui Chemicals, Inc.
3) Amine-based anti-aging agent: N- [1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine 4) In Comparative Example 3, the outer rubber was inhibited by vulcanization. Since the surface was tacky and the surface of the rubber jacket was damaged when the mold was peeled off, the operation was stopped once and was not repeated.

[0019]

By using the resin composition of the present invention, a vulcanization mold used for peroxide vulcanization of a rubber-like elastic body can be provided with a mold having excellent durability and a large number of repeated uses. it can. The method of the present invention of providing the vulcanization mold on the surface and peroxide vulcanizing the rubber-like elastic body includes, for example, rubber pipes, tubes,
It can be preferably applied to the manufacture of hoses and the like.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view showing a structure of a hose manufactured in an example and a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner surface resin 2 Inner tube rubber layer 3 Inner tube layer 4 Reinforcement thread and intermediate rubber layer 5 Outer rubber

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 23/16 C08L 23/16 // B29K 9:00 B29K 9:00 19:00 19:00 105: 24 105: 24 F-term (reference) 4F070 AA13 AA15 AA40 AC56 AE08 GA05 GC04 4F202 AA09 AA46 AB03 AB06 AJ03 AJ07 AR06 CA27 CB01 CD01 CD30 CK90 CM26 4F203 AA09 AA46 AB03 AB06 AJ03 AJ07 AR06 DA11 DB01 DC01 ED02 076066

Claims (8)

[Claims] 1. A resin composition used for a vulcanization mold provided on the surface of a rubber-like elastic body when peroxide-vulcanizing the same, comprising: a thermoplastic resin having a melting temperature of 200 ° C. or higher;
A resin composition for a vulcanization mold, comprising 0.4 to 5.5 parts by weight of an amine antioxidant per 100 parts by weight thereof. 2. The resin composition for a vulcanization mold according to claim 1, wherein the thermoplastic resin having a melting temperature of 200 ° C. or more contains polymethylpentene. 3. The resin composition for a vulcanization mold according to claim 1, wherein the amine-based antioxidant is a secondary aromatic amine. 4. A vulcanization mold is provided on the surface, and in vulcanizing the rubber-like elastic body with peroxide, the resin composition according to claim 1 is used as the vulcanization mold. Peroxide vulcanization of rubber-like elastic material. 5. The method according to claim 1, wherein the resin composition is used repeatedly as a vulcanization mold, and the content of the amine-based anti-aging agent is within a predetermined range. The peroxide vulcanization method for a rubber-like elastic material according to claim 4, wherein an agent is added. 6. The method according to claim 4, wherein the rubber-like elastic body is ethylene-propylene rubber (EPR) and / or ethylene-propylene-diene rubber (EPDM). 7. The rubber-like elastic material according to claim 4, wherein the peroxide used for peroxide vulcanization is at least one selected from dialkyl peroxides, peroxy esters and peroxy ketals. Peroxide vulcanization method. 8. The peroxide vulcanization method for a rubber-like elastic material according to claim 4, wherein the vulcanization temperature is 110 to 190 ° C.