JPS63179945A - Reinforced rubber composition and production thereof - Google Patents

Abstract

PURPOSE:To obtain a rubber composition having excellent productivity and processability and giving a vulcanized product having excellent mechanical properties, by kneading and extruding an ethylene-propylene-diene copolymer rubber, short fibers of a polyamide and a coupling agent at a temperature above a specific level. CONSTITUTION:(A) 100pts.wt. of an ethylene-propylene-diene copolymer rubber (preferably having a Mooney viscosity of 5-80 and an iodine value of 4-30) is compounded with (B) 2-100pts.wt. of fine short fibers of a thermoplastic polyamide (preferably short fibers having an average diameter of 0.05-0.8mum and fiber length of 10mum and made of nylon 6, nylon 66, etc., having a melting point of 180-260 deg.C) and (C) 0.2-5pts.wt. (based on 100pts.wt. of A+B) of a coupling agent (preferably silane coupling agent, etc.). The mixture is kneaded at a temperature above the melting point of the component B and extruded to obtain a reinforced rubber composition wherein the short fibers of the component B are embedded in the component A and the component A is grafted to the polyamide of the component B at the surface of the short fiber via the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel reinforced rubber composition with excellent productivity and processability as well as excellent mechanical properties of the vulcanizate, and a method for producing the same. The reinforced rubber composition of the present invention is used for manufacturing rubber parts for automobiles, industrial rubber products, and rubber products in general.

[Conventional technology and its problems]

EPDM is an ethylene-propylene-diene copolymer
Due to its excellent heat resistance and weather resistance, rubber is widely used as a material for industrial rubber products such as heat-resistant rubber hoses, heat-resistant rubber belts, vibration-proof rubber, and sponge rubber. When ordinary EPDM rubber is used as a manufacturing material for the above-mentioned products, various reinforcing agents are added depending on the type of product. Examples of such reinforcing agents include inorganic reinforcing agents such as carbon blank, silica, magnesium carbonate, and magnesium silicate, and organic reinforcing agents such as phenol formaldehyde resin, polyamide fibers, aramid fibers, and polyester fibers.

EPDM rubber compositions containing the above-mentioned reinforcing agents have increased green strength when unvulcanized, and the vulcanized product also exhibits a high elastic modulus, but in order to increase this effect, a large amount of reinforcing agents must be blended. Must-have. However, when a large amount of the above-mentioned reinforcing agent is blended, the fluidity and roll processability deteriorate, and the surface smoothness of the extrudate during extrusion molding also decreases, resulting in a decrease in productivity and a decrease in practical value. Furthermore, among the organic reinforcing agents, when organic fibers are used as reinforcing agents, it is customary to subject the organic fibers to RFL treatment in order to improve the adhesiveness or adhesion between the organic fibers and the EPDM rubber. but,
No suitable RFL processing method has yet been developed.

For the reasons mentioned above, it is not possible to incorporate a large amount of the reinforcing agent into EPDM rubber, and therefore it is not possible to sufficiently increase the green strength of EPDM rubber. For this reason, the manufacturing process for extruded rubber products requires the cumbersome process of semi-vulcanization, the insertion of a mandrel to prevent deformation, and special vulcanization equipment, making the process complex and costly. cause the amplifier.

In addition, since there is no appropriate RFL treatment method, organic fibers and EP
The interfacial bond with the DM rubber is weak, and in the tensile test of the vulcanizate, voids occur near the interface of the organic fiber during the elongation process, resulting in a decrease in tensile strength and elongation at break.

Inorganic reinforcing agents with low reinforcing effects, such as silica, magnesium carbonate, magnesium silicate, calcium carbonate,
EPDM rubber compositions containing reinforcing agents such as clay and alumina have low green strength, so special technology and equipment are required to produce hollow-shaped products or extruded products with complex cross-sectional shapes. Naturally, there are limits to the shape of the product.

Further, as a method of increasing the green strength of an EPDM rubber composition, it is known to blend EPDM rubber with a high ethylene component content ratio, but by blending the EPDM rubber, the green strength increases by at most about twice. It's nothing more than that. Moreover, as a result of the combination, disadvantages such as a decrease in cold resistance due to crystallization of the ethylene component and a decrease in crack growth resistance for unknown reasons arise.

Furthermore, as shown in (■) to (■) below, various rubber compositions and resin compositions are known, but these satisfy productivity and processability, and are suitable for forming vulcanizates and molded products. It cannot satisfy good mechanical properties.

■Unexamined Japanese Patent Publication No. 60-139729 discloses tackifier,
A composition containing as essential components a vulcanizable synthetic rubber, a thermoplastic polymer having an amide group, a novolak type phenolic resin, and a formaldehyde donor is disclosed. Specifically, as is clear from Example 13 of the above-mentioned publication, this composition contains a tackifier, EPDM, 6-nylon short fibers, novolak type phenolic resin, and hexamethylenetetramine as essential components, and contains the above-mentioned EPDM and above 6
- Short nylon fibers are grafted via a novolac type phenolic resin.

(2) JP-A-61-120855 discloses a composition containing polyphenylene ether, polyamide, and a silane derivative as essential components.

In this resin composition, the presence of a graft reaction product between polyphenylene ether and polyamide via a silane derivative is presumed, but neither polyphenylene ether nor polyamide are short fibrous materials, and they are not included in this resin composition. There are no chemical bonds between less than 50% by weight of the rubbery high molecular weight polymer and the polyphenylene ether or polyamide.

■Unexamined Japanese Patent Publication No. 49-104992 describes ethylene α
An additive obtained by heating a mixture of an olefin/non-coterminous diene copolymer and maleic anhydride is disclosed.

■Unexamined Japanese Patent Publication No. 51-143061 discloses that polyamide is used as a matrix and fine specific polymers are dispersed therein.
A reinforced multiphase thermoplastic composition is disclosed.

■JP-A-54-63150 and JP-A-54-6
No. 3151 discloses a polyamide resin composition containing a polyamide resin, an epoxy-modified olefin polymer, and a lubricant as essential components.

■Unexamined Japanese Patent Publication No. 60-63242 includes Ep6M and EP
A composition of DM with a thermoplastic resin grafted with an aromatic vinyl monomer is disclosed.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a reinforced rubber composition that has excellent productivity and processability, as well as excellent mechanical properties of the vulcanizate, and a method for producing the same. It is in.

[Failure to solve the problem]

The present invention has the object of "-", in which 2 to 100 parts by weight of fine short fibers of thermoplastic polyamide are embedded in 100 parts by weight of ethylene-propylene-diene copolymer rubber,
and the polyamide and the copolymer rubber are grafted via a coupling agent of 0.2 to 5 parts by weight (an amount based on 100 parts by weight of the total amount of the copolymer rubber and the polyamide) at the interface of the short fibrous material. This has been achieved by providing a reinforced rubber composition characterized by:

The present invention also provides a method for producing the above-mentioned reinforced rubber composition, which includes kneading and extruding ethylene-propylene-diene copolymer rubber, a thermoplastic polyamide, and a coupling agent at a temperature higher than the melting temperature of the thermoplastic polyamide. The present invention provides a method for producing a reinforced rubber composition characterized by the following.

The reinforced rubber composition of the present invention has excellent surface smoothness during extrusion molding and high green strength, which is considered to be a measure of shape retention, compared to EPDM compositions containing ordinary organic fiber reinforcing agents. It is possible to incorporate large amounts of softeners, plasticizers, and fillers, and it can be said that the composition is excellent in productivity, processability, and economy.

In addition, the vulcanizate of the reinforced rubber composition of the present invention has an elastic modulus, for example, an elastic modulus M at 100% elongation, o0, which is equivalent to that of an EPDM composition containing a normal organic fiber reinforcing agent, and an inorganic reinforced rubber composition. It shows a larger value than the EPDM composition containing the agent.

Furthermore, the vulcanizate of the reinforced rubber composition of the present invention exhibits a tensile strength greater than that of an EPDM composition containing an ordinary organic fiber reinforcing agent, and contains an inorganic reinforcing agent with high reinforcing properties, such as carbon blank. It shows a value equivalent to or higher than that of the EPDM composition.

Therefore, it can be said that the vulcanizate of the reinforced rubber composition of the present invention has well-balanced and excellent mechanical properties.

The reinforced rubber composition of the present invention will be explained in detail below.

Ethylene-propylene-diene copolymer rubber (hereinafter referred to as EPDM rubber) used in the reinforced rubber composition of the present invention
As, its Mooney viscosity (ML, or 4.1.00℃
) is preferably in the range of 5 to 80, the iodine value is in the range of 4 to 30, and the molar ratio of ethylene units to propylene units is in the range of 50,150 to 80/20.

In addition, the thermoplastic polyamides used in the reinforced rubber composition of the present invention include nylon 6, nylon 66, nylon 12, nylon 610, which have a melting point of 180 to 260°C.
Nylon 611 and nylon 612 are preferred.

In the reinforced rubber composition of the present invention, the fine short fibers of thermoplastic polyamide embedded in the EPDM rubber have molecules arranged in the fiber axis direction, have a circular cross section, and have an average diameter of 0.05-0.8μm, fiber length 10
μm or more and 90% by weight or more of the fiber is 1000 μm or more
It is embedded in the form of less than m.

The proportion of the short fibers embedded in the EPDM rubber is 2 to 10 parts by weight based on 100 parts by weight of the EPDM rubber.
If it is less than 0 parts by weight, preferably 3 to 80 parts by weight, the green strength and the elastic modulus of the vulcanizate will decrease,
If it exceeds 100 parts by weight, processability will be poor.

Further, as the coupling agent used in the reinforced rubber composition of the present invention, a silane coupling agent, a titanate coupling agent, an unsaturated carboxylic acid, or a mixture thereof is preferable.

Examples of the silane coupling agent include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, T-methacryloxypropyltrimethoxysilane, β-(3,4-,I-poxycyclohexyl)ethyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ- Aminopropylmethyldimethoxysilane, γ
-aminopropyltriethoxysilane, N-phenyl-
Examples include γ-aminopropyltrimethoxysilane, T to mercaptopropyltrimethoxysilane, and particularly silane coupling agents having an amine group, mercapto group, or vinyl group can be preferably used.

Further, examples of the titanate coupling agent include isopropyltriisostearoyl titanate, isopropyltri(N-aminoethyl-aminoethyl)
Titanate, tetra(2,2-diallyloxymethyl-
Examples include 1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctylpyrophosphate)oxyacetate titanate, isopropyltrioctanoyltitanate, isopropyldimethacrylyisostearoyltichnate, isopropylisostearoyldiacryltitanate, etc. Among them, amino A titanate-based pulling agent having a vinyl group or a vinyl group can be suitably used.

In addition, the unsaturated carboxylic acids include α, β unsaturated carboxylic acids, alicyclic unsaturated carboxylic acids, alkenyl carboxylic acids, and derivatives thereof, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, Itaconic acid, vinylbenzoic acid, vinyl phthalic acid, maleic anhydride, itaconic anhydride, endo-bicyclo(2,2,1>-5-heptene-2,3-carboxylic acid, cis-4-cyclohexene-1,2- Carboxylic acid, octadecenyl succinic acid, etc.
and derivatives thereof such as anhydrides, esters, and metal salts. Among these, maleic acid, fumaric acid, itaconic acid, vinylbenzoic acid, vinyl phthalic acid, maleic anhydride, and itaconic anhydride can be preferably used.

The amount of the coupling agent used is 0.2 to 100 parts by weight in total of the EPDM rubber and the polyamide.
5 parts by weight, preferably 0.3 to 3 parts by weight. Although it varies depending on the type of coupling agent, if the amount of the coupling agent used is less than the above range, the number of bonds between the EPDM rubber and the polyamide, the so-called graft ratio, will decrease.
The diameter of the short polyamide fibers increases. If the amount is too large, the fiber length of the short polyamide fibers becomes short, and the reinforcing effect of the rubber compound decreases.

Further, in the reinforced rubber composition of the present invention, the EPD
1 Ratio of the weight of the EPDM rubber grafted to the polyamide (grafted EPDM rubber/ Grafting ratio expressed by fine short fibers of thermoplastic polyamide is 2 to 20
It is preferable that the polyamide forming the fibrous material and the EPDM rubber are graft-bonded via a coupling agent such that the amount of the polyamide is % by weight.

Further, the reinforced rubber composition of the present invention may contain vulcanizable rubber, inorganic fillers, softeners, etc. as optional components.

Examples of the above-mentioned vulcanizable rubber include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, nitrile rubber, butyl rubber, etc. When these vulcanizable rubbers are blended, they can be mixed with the above-mentioned EPDM rubber. 2 to 100 parts by weight of the total amount of the above vulcanizable rubber
Preferably, 100 parts by weight of fine short fibers of the thermoplastic polyamide are included.

Further, examples of the inorganic filler include carbon blank, anhydrous silicic acid, hydrated silicic acid, silicate compounds such as synthetic silicates, calcium carbonate, relay, etc. The amount is preferably 300 parts by weight or less based on 100 parts by weight of EPDM rubber.

In addition, as the above-mentioned softening agent, paraffin-based process oil,
Naphthenic process oil, aromatic process oil, petroleum resin, polymerized high boiling point strong aromatic oil, paraffin, liquid paraffin, mineral oil softener such as white oil, cottonseed oil,
Vegetable oil-based softeners such as rapeseed oil, palm oil, rosin, and pine tar; sabu such as black and white sabu; fatty acids such as ricinoleic acid, balmitic acid, stearic acid, and lauric acid; barium stearate, calcium stearate, and zinc stearate. Examples include fatty acid salts such as

The reinforced rubber composition of the present invention also contains sulfur, vulcanizing agents such as sulfur-containing compounds, organic peroxides such as dicumyl peroxide and ditertiary butyl peroxide, and organic vulcanization accelerators such as aldehydes, ammonias, and aldehydes. Vulcanization accelerators such as amines, guanidines, thioureas, thiazoles, thiurams, dithiocarbamates, and dithiophosphates can be blended.

In addition, in the reinforced rubber composition of the present invention, a compounded rubber composition in which EPDM rubbers of the same type or different types are mixed and compounded may also be used.
When 2 to 100 parts by weight of the short fibers of the thermoplastic polyamide are embedded per 100 parts by weight of the rubber component of the compounded rubber composition, the performance is equivalent to that of the reinforced rubber composition of the present invention. Regardless of the blending method used, such compositions also fall within the scope of the reinforced rubber compositions of the present invention.

The above-described reinforced rubber composition of the present invention can be produced efficiently and with stable quality by the above-described method for producing a reinforced rubber composition of the present invention, for example, the following method.

100 parts by weight of the EPDM rubber, 2 to 1 parts by weight of the polyamide
00 parts by weight, 0.2 to 5 parts by weight of the coupling agent and 20 parts by weight or less of a tackifier, and further 5 parts by weight or less as necessary, based on 100 parts by weight of the total amount of the EPDM rubber and the polyamide. A mixture containing an anti-aging agent of 1 to 1 is mixed using a Banbury mixer, a roll, or an extruder at a temperature higher than the melting temperature of the polyamide.
After kneading for 30 minutes, the resulting kneaded product is extruded at a temperature above the melting temperature of the polyamide and preferably below 280°C, and then the extrudate is wound up to obtain the reinforced rubber composition of the present invention.

Further, the above-mentioned optional components such as vulcanizable rubber, inorganic filler, and softener are appropriately added to the above mixture as necessary.

According to the method of the present invention, the EPDM rubber is used as a continuous phase, and the polyamide is used as a fine short fibrous material.
It can be dispersed in PDM rubber, and the polyamide and the EPDM rubber can be graft-bonded via the coupling agent at the interface of the short fibrous material. In the thus obtained reinforced rubber composition of the present invention, the fine short fibers of the polyamide have a circular cross section, an average diameter of 0.05 to 0.8 μm, and a fiber length of 10 μm or more and 90% by weight of the fiber
The above particles are embedded in the EPDM rubber in the form of 1000 μm or less.

In the method of the present invention, the coupling agent can be melt-blended in advance with the thermoplastic polyamide, deposited on the surface of the polyamide, or dispersed in the EPDM rubber. It may be added during kneading, any method may be used, or a combination of the above methods may be used.

Furthermore, in the method of the present invention, the EPDM rubber is used in an amount of 2 to 50 parts by weight per 100 parts by weight of the thermoplastic polyamide, and the coupling agent is added in an amount of 0.2 to 5 parts by weight per 100 parts by weight of the total N of the thermoplastic polyamide and EPDM rubber. Part by weight is added, kneaded at a temperature higher than the temperature at which the polyamide melts, and further E
PDM may be added, and if necessary, a coupling agent may be added and kneaded, followed by extrusion at a temperature higher than the temperature at which the polyamide melts.

〔Example〕

EXAMPLES Hereinafter, the reinforced rubber composition of the present invention and its manufacturing method will be explained in more detail with reference to Examples and Comparative Examples. The raw material names, product names, and manufacturing company names used in Examples and Comparative Examples are summarized in Table 1 below. Moreover, in the following description, parts indicate parts by weight.

Example 1 In a Banbury mixer adjusted to 150°C, 100 parts of EP-33, 5 parts of 1030u (nylon 6), 2 parts of Tamanol 510, 1 part of Tsuklak G1, and KBM6 were added.
0.5 part of 03 was added and kneaded for 10 minutes. During this time, the temperature inside the mixer rose to 240°C, and 1030u was melted and finely dispersed in EP-33, and BP-33 was graft-bonded to the interface of the dispersed particles. The obtained kneaded product was extruded from an extruder using a die with an inner diameter of 2 mm, then wound up at a draft ratio of 20 and rolled with rolls to obtain a reinforced rubber composition of the present invention.

The obtained reinforced rubber composition was analyzed as follows.

2 g of the reinforced rubber composition was added to 200 mff1 of toluene at room temperature or 80° C. to melt the rubber component in the reinforced rubber composition, and the resulting slurry was centrifuged to separate into a solution portion and a precipitate portion.

After repeating the above-described toluene dissolution and centrifugation operations for the precipitated portion seven times, the precipitated portion was dried to obtain a nylon fibrous material. The shape and fiber diameter of the obtained nylon fibrous materials were measured using a scanning electron microscope at a magnification of 10,000 times for 400 fibrous materials.

In addition, the nylon fibrous material was dissolved in a mixed solvent of phenol and orthodichlorobenzene, and analyzed by IH nuclear magnetic resonance spectrum (NMR), and the NMR chart showed a peak of methylene groups adjacent to NH groups originating from nylon, The areas of the peaks of methyl groups caused by rubber were determined, and the molar ratio of nylon to rubber and the grafting rate were calculated.

Example 2 A reinforced rubber composition of the present invention was obtained in the same manner as in Example 1, except that the amount of 1030u used was changed to 50 parts by weight and the amount of KBM603 used was changed to 1 part by weight.

The obtained reinforced rubber composition was analyzed in the same manner as in Example 1.

Example 3 The amount of 1030u used was changed to 80 parts by weight, and KBC
A reinforced rubber composition of the present invention was obtained in the same manner as in Example 2 except that 1 part by weight of 1003 was added.

The obtained reinforced rubber composition was analyzed in the same manner as in Example 1.

Comparative Example I A rubber composition was obtained in the same manner as in Example 2 except that the amount of KBM603 used was changed to 0.1 parts by weight.

The obtained rubber composition was analyzed in the same manner as in Example 1.

Example 4 100 parts by weight of EP33, 2 parts by weight of Tamanol 510,
and 1 part by weight of Tsurank G1 were mixed using a 10-inch roll. The obtained mixture, 1030u, KBM603, and KBM803 were continuously fed to a 65-fin kneading extruder (manufactured by Ikegu Iron Works) at a feed ratio of 103:5o:o, s:o, and 5. The temperature of the screw tip, head, and nozzle was set at 250° C., and the discharge rate was 16 kg/hr. The obtained extrudate was fed to a 50-frame extruder (manufactured by Nippon Steel) and heated at 250°C.
Spinning was carried out at a temperature of , draft ratio 15, winding speed 45 m.
/n+in and supplied to a 60-Ryu plasticizing extruder (manufactured by Mitsuha Seisakusho) to obtain a reinforced rubber composition of the present invention. At this time, the plasticizing temperature was 120°C.

The obtained rubber composition was analyzed in the same manner as in Example 1.

Examples 5 to 6 The type and amount of coupling agent used were changed (Example 5
Reinforced rubber compositions of the present invention were obtained in the same manner as in Example 4, except that 1 part by weight of Prenact KR44 was used in Example 6, and 0.5 parts by weight of KBM603 was used in Example 6. Analysis of the obtained rubber composition is shown in Example 1.
The same procedure was used.

Example 7 100 parts by weight of EP33, 2 parts by weight of Tasoquirol EP20, and 1 part by weight of Naragard XL-1 were mixed using a 10-inch roll. The mixture, 2020u and KBM6
03 and plain act KR7 103 = 50:0.5:0
．． 30■ Twin-screw kneading extruder (manufactured by Nakagama Seisakusho) with a feed ratio of 5
was continuously supplied.

The temperature of the screw tip, head and nozzle is 270°
C, and the discharge amount was 5 kg/hr. The raw materials kneaded in the extruder are passed through a nozzle (L/D
= 2, D = 2 dragon φ, 10 holes) and wound up at a draft ratio of 15. The rolled material was plasticized using a 10-inch roll to obtain a reinforced rubber composition of the present invention. The obtained rubber composition was analyzed in the same manner as in Example 1.

Example 8 A reinforced rubber composition of the present invention was obtained in the same manner as in Example 7 except that BP43 was used instead of EP33. The obtained rubber composition was analyzed in the same manner as in Example 1.

Example 9 The type and amount of coupling agent used were changed (KBM60
(1 part by weight of 3 and 1 part by weight of maleic anhydride were used)
Except for this, a reinforced rubber composition according to the invention was obtained in the same manner as on the day of the example. The obtained rubber composition was analyzed in the same manner as in Example 1.

Example 10 A reinforced rubber composition of the present invention was prepared in the same manner as in Example 7, except that 1 part by weight of Brenact KR44 and 1 part by weight of maleic anhydride were used to change the type and amount of the coupling agent added. Obtained. The obtained rubber composition was analyzed in the same manner as in Example 1.

The composition ratios of the raw materials in Examples 1 to 10 and Comparative Example 1 and the analysis results of the obtained reinforced rubber compositions are summarized in Table 2 below.

Next, the excellent properties of the reinforced rubber composition of the present invention will be clarified by the following examples (test examples).

Example 11 65.1 parts of the reinforced rubber composition obtained in Example 1, BP2
2 40 parts, HAF carbon black 50 parts, naphthenic process oil (Koumoresox No. 2, manufactured by Nippon Oil) 25
1 part, 5 parts of zinc white, and 1 part of stearic acid were kneaded for 5 minutes using a Banbury mixer. The temperature inside the mixer at the start of kneading was 60°C, and the rotor rotation speed was 75R.
It was designated as PM.

To the obtained kneaded material, 31.5 parts of vulcanization accelerator T, 1.5 parts of vulcanization accelerator Mo2S, and 1.5 parts of sulfur were blended with 100 parts of the rubber component of the kneaded material using a 10-inch roll,
An unvulcanized rubber compound was prepared.

The physical properties of this unvulcanized rubber compound and the physical properties of a vulcanized product of this compound were measured as follows.

The shear viscosity ηa and die swell ratio of the above formulation were measured using a cavilograph (manufactured by Toyo Seiki), and the surface smoothness of the extrudate was visually observed. The measurement conditions were: temperature 100°C, shear rate 1005ec-'
, the capillary L/D (1 dragon φ).

Further, the roll processability of the above-mentioned compound was judged based on the smoothness of the sheet obtained by dispensing the sheet with a roll and the ability to wrap the sheet around the roll.

Create a sheet with a thickness of 2.3 cm using a roll, place it in a real press mold (150 mm x 150 mm x 20 tons), and place it at 80°C for 60 minutes (for green strength measurement, unvulcanized sheet). ) or 160'CX 30 minutes (for measuring properties of vulcanized materials)
Samples were prepared under the following conditions.

The unvulcanized sheet was punched out using a JIS No. 1 dumbbell in a direction parallel to the grain, and a tensile test was performed on the test piece to measure the tensile strength (green strength).

Measurement temperature was 22℃, tensile speed 100 ++ m/min
, the distance between gauges was set at 20 brightness. The maximum stress during the stretching process was defined as the green strength.

Regarding the vulcanized sheet, measurements were performed according to the regulations of JIS K6301. In the normal temperature tensile test, a JISI dumbbell was punched in a direction parallel to the grain of the sheet to form a test piece, and in the heat aging test, the No. 1 dumbbell was punched in an air atmosphere at 150°C for 72 hours using a gear aging tester. After being exposed to water, each dumbbell was measured in the same manner as the tensile test above.

In the tear test, a B-type test piece was punched out in the direction perpendicular to the grain of the vulcanized sheet, and the tear strength TR was measured using a tensile tester.
(Kgf/cm) was measured.

Example 12 Example 2 was used instead of the reinforced rubber composition obtained in Example 1.
61.6 parts of the reinforced rubber composition obtained in BP2
An unvulcanized rubber compound was prepared in the same manner as in Example 11, except that 600 parts of No. 2 was added. The physical properties of this unvulcanized rubber compound and the physical properties of the vulcanized product of this compound were measured in the same manner as in Example 11.

Example 13 Example 3 was used instead of the reinforced rubber composition obtained in Example 1.
185 parts by weight of the reinforced rubber composition obtained in EP
An unvulcanized rubber compound was prepared in the same manner as in Example 11 except that No. 22 was not blended.

The physical properties of this unvulcanized rubber compound and the physical properties of the vulcanized product of this compound were measured in the same manner as in Example 11.

Example 14 Example 7 was used instead of the reinforced rubber composition obtained in Example 1.
30.8 parts of the reinforced rubber composition obtained in BP2
An unvulcanized rubber compound was prepared in the same manner as in Example 11, except that 800 parts of No. 2 was added. The physical properties of this unvulcanized rubber compound and the physical properties of the vulcanized product of this compound were measured in the same manner as in Example 11.

Example 15 Example 9 was used instead of the reinforced rubber composition obtained in Example 1.
An unvulcanized rubber compound was prepared in the same manner as in Example 11, except that 311 parts of the reinforced rubber composition obtained in 1 and 800 parts of EP22 were used. The physical properties of this unvulcanized rubber compound and the physical properties of the vulcanized product of this compound were measured in the same manner as in Example 11.

Comparative Example 2 An unvulcanized rubber compound was prepared in the same manner as in Example 11, except that 100 parts of EP22 was blended without the reinforcing rubber composition. The physical properties of this unvulcanized rubber compound and the physical properties of the vulcanized product of this compound were measured in the same manner as in Example 11.

The measurement results of the physical properties of the unvulcanized rubber compound obtained in Examples 11 to 15 and Comparative Example 2 and the physical properties of the vulcanized product of the compound are summarized in Table 3 below.

Table 1 [Effects of the invention] The reinforced rubber composition of the present invention has excellent productivity and processability,
Furthermore, the vulcanizate has excellent mechanical properties.

That is, the reinforced rubber composition of the present invention has fluidity when unvulcanized,
It has excellent roll processability and the surface of the extruded product is smooth.
It has high green strength and excellent shape retention, so it has excellent productivity and processability.In addition, its vulcanizate has, for example, a high modulus of elasticity, high strength and elongation, and high tear resistance. In particular, the heat aging resistance properties are far superior to those of conventional EPDM compositions.

In addition, the reinforced rubber composition of the present invention has the above-mentioned properties and a small die swell during extrusion, so it can be used for rubber extrusion products with complicated shapes, automotive radiator hoses, heater hoses, industrial heat-resistant belts, heat-resistant hoses, etc. It can be suitably used for manufacturing heat-resistant rolls and rubber parts exposed to high temperatures.

Further, according to the production method of the present invention, the above-mentioned reinforced rubber composition of the present invention can be produced efficiently and with stable quality.

Claims (4)

[Claims] (1) Ethylene-propylene-diene copolymer rubber 100
2 to 2 parts by weight of fine short fibers of thermoplastic polyamide
100 parts by weight of the coupling agent is embedded in the polyamide and the copolymer rubber at the interface of the short fibrous material (the total amount of the copolymer rubber and the polyamide is 100 parts by weight). 1. A reinforced rubber composition characterized in that the composition is grafted in a proportion (based on parts by weight). (2) The reinforced rubber composition according to claim (1), wherein the coupling agent is a silane coupling agent, a titanate coupling agent, an unsaturated carboxylic acid, or a mixture thereof. (3) A method for producing a reinforced rubber composition, which comprises kneading and extruding an ethylene-propylene-diene copolymer rubber, a thermoplastic polyamide, and a coupling agent at a temperature higher than the temperature at which the thermoplastic polyamide melts. (4) The method for producing a reinforced rubber composition according to claim (3), wherein the coupling agent is a silane coupling agent, a titanate coupling agent, an unsaturated carboxylic acid, or a mixture thereof.