JPH06240051A - Vulcanizable rubber composition and vulcanized rubber - Google Patents

Abstract

PURPOSE:To obtain a rubber compsn. which, when vulcanized, gives a vulcanizate having high strengths, stiffness, and hardness without detriment to high resistances to weather, ozone, and heat inherent in EPDM. CONSTITUTION:This rubber compsn. contains 100 pts.wt. rubber component comprising 3-85wt.% ethylene/alpha-olefin/nonconjugated diene copolymer rubber and 15-70wt.% styrene/butadiene random copolymer, 5-50 pts.wt. styrene resin, 20-150 pts.wt reinforcing filler, 0-100 pts.wt. extender oil, and 3-10 pts.wt. sulfur.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vulcanizable rubber composition and a vulcanized rubber produced using the same. INDUSTRIAL APPLICABILITY The vulcanizable rubber composition and the vulcanized rubber according to the present invention can be used in a wide range of fields such as automobile parts, industrial parts and building materials.

[0002]

2. Description of the Related Art At present, ethylene / α-olefin / non-conjugated diene copolymer rubber (hereinafter sometimes referred to as EPDM because propylene is generally used as the α-olefin) has weather resistance and ozone resistance. Since it is excellent in heat resistance and workability, it is widely used in fields such as automobile parts, industrial parts and building materials. But EPD
It has heretofore been difficult to provide characteristics such as high strength, high rigidity and high hardness without impairing these characteristics of M. For example, natural rubber, styrene-butadiene rubber,
When a diene rubber such as acrylonitrile-butadiene rubber is used as the rubber component, a large amount of sulfur can be used to easily add a high hardness of 50 (hardness measured by Durometer D type according to ASTM D2240). Although a vulcanized rubber can be obtained, the vulcanized rubber thus obtained generally has insufficient weather resistance and heat resistance. On the other hand, EP
With a rubber having a low degree of unsaturation such as DM, it is not possible to obtain a rubber having a high hardness by the method using a large amount of sulfur as described above. JP-A-64-90240 discloses EPD.
A method of compounding a rubber component of M and / or isobutylene / isoprene copolymer rubber with a solid rubber-like substance containing butadiene and sulfur is disclosed. By this method, a vulcanized rubber having high hardness is obtained. Although it is possible to obtain a vulcanizable rubber composition, further improvement is desired in terms of the hardness of the vulcanized rubber.

[0003]

The present invention is a vulcanized rubber having high strength, high rigidity and high hardness without impairing the weather resistance, ozone resistance and heat resistance which are the features of EPDM,
And to provide a vulcanizable rubber composition that provides the same.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that ethylene / α-
Olefin / non-conjugated diene copolymer rubber: 30-85w
t% and styrene / butadiene random copolymer: 15 to 15%
5 to 50 parts by weight of styrenic resin, 20 to 150 parts by weight of reinforcing filler, 0 to 100 parts by weight of extender oil, and 3 to 10 of sulfur per 100 parts by weight of a rubber component composed of two binary components of 70 wt%. By vulcanizing the vulcanizable rubber composition containing parts by weight, it is possible to obtain a vulcanized rubber having excellent weather resistance, ozone resistance and heat resistance, and having high strength, high rigidity and high hardness. Found and completed the present invention. The present invention will be described in detail below.

Α which is a constituent of EPDM used in the present invention
Examples of the olefin include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene, and examples of the non-conjugated diene include 1,4-pentadiene, 1,4-hexadiene and divinylbenzene. Examples thereof include dicyclopentadiene, methylene norbornene, ethylidene norbornene and vinyl norbornene. Among them, propylene and 1-butene are used as the α-olefin, dicyclopentadiene is used as the non-conjugated diene,
Ethylidene norbornene is preferably used.

The ethylene / α-olefin ratio (weight ratio) in the EPDM is not particularly limited, but is usually 50/50 to 90/10, preferably 6 in terms of the strength of the vulcanized rubber.
It is 0/40 to 80/20. The iodine value of the EPDM is also not particularly limited, but in view of strength and elongation of the vulcanized rubber, it is usually 20 to 45, and particularly preferably 20 to 35. Mooney viscosity of the EPDM (ML _{1 + 4} 100
(° C) is not particularly limited, but from the viewpoint of the processability of the vulcanizable rubber composition and the strength of the vulcanized rubber, it is usually 10 to 100, and particularly preferably 20 to 75.

The styrene content in the styrene / butadiene random copolymer (hereinafter referred to as "SBR") used in the present invention is not particularly limited, but it is usually 10 to 70 wt from the viewpoint of hardness and strength of the vulcanized rubber. %, Preferably 20 to 50 wt%, more preferably 35 to 45 wt
It is good to set it as%. It is preferable that 30% or more of the double bonds derived from butadiene in the SBR are 1,2 bonds. Mooney viscosity of the SBR (ML _{1 + 4} 100
The temperature is not particularly limited, but it is usually preferably 20 to 100 from the viewpoint of the processability of the vulcanizable rubber composition and the strength of the vulcanized rubber.

In the rubber component composed of two elements, EPDM and SBR, used in the present invention, the compounding ratio of EPDM is 30.
~ 85 wt%. EPDM compounding ratio is 30 wt%
If the amount is less than the above range, the elongation of the vulcanized rubber decreases, which is not preferable. On the other hand, if it is more than 85 wt%, the hardness of the vulcanized rubber becomes low and a desired hardness cannot be obtained.

The vulcanizable rubber composition of the present invention has the above-mentioned EP
It comprises a styrene-based resin, a reinforcing filler, sulfur, and, if necessary, an extender oil together with a binary rubber component of DM and SBR.

As the styrene resin in the present invention,
Besides styrene homopolymer (GPPS), rubber-modified polystyrene (HIPS), styrene-acrylonitrile copolymer (AS), styrene-butadiene-acrylonitrile copolymer (ABS), etc.
PPS and AS are preferably used. The addition amount is usually 5 to 50 parts by weight per 100 parts by weight of the rubber component. If it is less than 5 parts by weight, the hardness after vulcanization is low, and if it exceeds 50 parts by weight, the elongation and strength of the vulcanized rubber decrease, which is not preferable.

Examples of the reinforcing filler used in the present invention include carbon black and silica, among which carbon black is preferably used. The compounding amount of the reinforcing filler is usually 20 to 150 relative to 100 parts by weight of the rubber component.
Parts by weight, preferably 30 to 120 parts by weight.
If the compounding amount of the reinforcing filler is within the above range, high hardness,
It is possible to obtain a vulcanizable rubber composition having good processability that gives a vulcanized rubber having high strength.

As the extender oil used in the present invention, aromatic oils, naphthene oils, which are usually used for rubber applications,
Examples thereof include so-called process oils such as paraffin oil and vegetable oils such as coconut oil. Of these, process oils are preferable, and paraffin oil or naphthene oil is particularly preferable. The amount of the extender oil is usually 0 to 100 parts by weight of the rubber component.
It is 100 parts by weight, and the compounding amount thereof can be arbitrarily selected within this range according to desired workability and hardness of the vulcanized rubber. When the blending amount of the extender oil is in such a range, a vulcanizable rubber composition having high hardness and high strength and having good processability can be obtained.

The amount of sulfur in the present invention is usually 3 to 10 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the rubber component. If the sulfur content is less than 3 parts by weight, the strength and hardness of the vulcanized rubber will be low, which is not preferable. On the other hand, even if the amount of sulfur compounded exceeds 10 parts by weight, the elongation after vulcanization is reduced, excess sulfur is bloomed, and the effect of improving the hardness of the vulcanized rubber is not remarkable, which is not preferable.

In order to improve processability, a polyethylene resin or a polypropylene resin may be added to the vulcanizable rubber composition of the present invention, if necessary. The vulcanizable rubber composition of the present invention includes fillers, softeners, vulcanization accelerators, vulcanization aids, processing aids, defoamers, zinc white, stearic acid, antioxidants, and other rubber applications. You may select and mix the compounding agent normally used suitably.

Conventionally known processing methods can be applied to the production of the vulcanizable rubber composition of the present invention. That is, compounding components such as styrene resin, reinforcing filler, extender oil and sulfur are added to a rubber component composed of two elements, EPDM and SBR,
These are mixed using an open roll mill, a Banbury mixer, a kneader or the like to obtain the vulcanizable rubber composition of the present invention. In order to produce the vulcanized rubber of the present invention from the vulcanizable rubber composition, the vulcanizable rubber composition is vulcanized after it is formed into a desired shape by extrusion molding, calender molding or the like, if necessary. Vulcanization methods include press vulcanization, can vulcanization, injection vulcanization, hot air vulcanization, UHF vulcanization, LCM vulcanization,
A continuous vulcanization method consisting of PCM vulcanization or a combination thereof can be adopted. Among them, the continuous vulcanization method capable of efficiently producing a long product is preferable as the method for producing the vulcanized rubber of the present invention.

The vulcanizable rubber composition of the present invention is used for the production of vulcanized rubber, and as a part of the rubber product itself, for example, as a surface layer, a lip portion, a core material portion and the like, other rubber compositions and It is compounded with a resin composition and used for the production of rubber products. The vulcanized rubber of the present invention is excellent in weather resistance, ozone resistance and heat resistance, and has high strength, high rigidity and high hardness, and therefore can be used in a wide range of fields such as automobile parts, industrial parts and building materials. You can As automotive parts, for example, packing, hoses, draining rubber, grass run rubber, weather strip, mudguard, solid rubber part in a composite of soft solid and hard solid, sponge applied to door seals and trunk seals. The solid rubber portion and the like in the composite of rubber and solid rubber, rubber rolls, sealing materials, packings and the like are industrial parts, and setting blocks, rubber tiles, gaskets and the like are building materials.

[0017]

When the vulcanizable rubber composition of the present invention is vulcanized, the vulcanized rubber has high strength, high rigidity and high hardness without impairing the weather resistance, ozone resistance and heat resistance originally possessed by EPDM. Is obtained.

[0018]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 15 In a BR Banbury mixer, after kneading among the compounding ingredients shown in Table-1 from EPDM to Hitanol 1501, the remaining compounding ingredients in Table-1 were further added. And kneaded with an open roll of 10 inches to prepare a vulcanizable rubber composition. The obtained vulcanizable rubber composition was vulcanized at 160 ° C. for 20 minutes using a press vulcanizer. Table 2 and Table 3 show the types and properties of EPDM and SBR used.
Table 4 and Table 5 show the combination of compounding ingredients, the compounding amount, and the physical properties of the obtained vulcanized rubber. The physical properties of the vulcanized rubber are JIS K6301 and ASTM D22.
It measured based on 40.

Comparative Examples 1 to 5 By the same method as in Example 1, the components were kneaded in the combinations and amounts of the components shown in Table 6 and then vulcanized. The physical properties of the vulcanized rubber obtained are shown in Table-6.

The vulcanized rubbers of Examples 1 to 15 of the present invention all have high strength, high rigidity and high hardness. On the other hand, the vulcanized rubbers of Comparative Examples 1 to 4 in which the styrene resin is compounded but the SBR is not compounded are excellent in hardness but inferior in tensile strength. Further, in Comparative Example 5 in which SBR and styrenic resin are compounded but the amount of sulfur compounded is small,
The hardness and tensile strength of the vulcanized rubber are poor.

[0022]

[0023]

[0024]

[0025]

[0026]

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Claims (6)

[Claims] 1. Styrene per 100 parts by weight of a rubber component consisting of a binary of ethylene / α-olefin / non-conjugated diene copolymer rubber: 30 to 85 wt% and styrene / butadiene random copolymer: 15 to 70 wt%. 5 resin
A vulcanizable rubber composition comprising: -50 parts by weight, 20-150 parts by weight of a reinforcing filler, 0-100 parts by weight of extender oil, and 3-10 parts by weight of sulfur. 2. The Mooney viscosity (ML _{1 + 4} 100 ° C.) of the ethylene / α-olefin / non-conjugated diene copolymer rubber is 10 to 100, and the ethylene / α-olefin ratio (weight ratio) is 50/50. ~ 90/10 with an iodine value of 2
The vulcanizable rubber composition according to claim 1, which is 0 to 45. 3. The vulcanizable rubber composition according to claim 1, wherein the α-olefin is propylene or 1-butene, and the non-conjugated diene is dicyclopentadiene or ethylidene norbornene. 4. The styrene-butadiene random copolymer has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 20 to 100 and a styrene component content of 10 to 70 wt%.
The vulcanizable rubber composition according to claim 1, wherein 30% or more of double bonds derived from butadiene are 1,2 bonds. 5. The vulcanizable rubber composition according to claim 1, wherein the styrene resin is polystyrene or a styrene-acrylonitrile copolymer. 6. A vulcanized rubber produced by continuous vulcanization using the vulcanizable rubber composition according to claim 1.