RUBBER COMPOSITE, PROCESSING METHOD, BRAKING-RESISTANT LIQUID PRODUCT APPLYING COMPOSITE, AND MANUFACTURING METHOD

Abstract

The present invention discloses a rubber composition, a processing method thereof, and also a brake fluid-resistant product using the rubber composition and a production method thereof. The rubber composition comprises, in parts by weight, 100 parts of a rubber matrix; 1.5-8 parts of a crosslinking agent 40-140 parts of a reinforcing filler; and 0-40 parts of a plasticizer, wherein the rubber matrix comprises, based on 100 parts by weight of the rubber matrix, a branched polyethylene with a content represented as A, in which 0<A100 parts; an EPM with a content represented as B, in which 0B<100 parts; and an EPDM with a content represented as C, in which 0C<100 parts. The rubber composition is useful in the production of brake fluid-resistant brake rubber hose and brake rubber diaphragm. The beneficial effect is that since the rubber composition comprises the branched polyethylene, the tear strength of the rubber compound is improved, thereby reducing the probability of tearing of the product during the production process and improving the overall processing performance.

Claims

1. A rubber composition, comprising a rubber matrix and essential components, wherein said rubber matrix comprises, based on 100 parts by weight of said rubber matrix, a branched polyethylene with a content represented as A, in which 0<A100 parts, an EPM with a content represented as B, in which 0B<100 parts, and an EPDM with a content represented as C, in which 0C<100 parts; and based on 100 parts by weight of said rubber matrix, said essential components comprise 1.5 to 8 parts of a crosslinking agent, 40 to 140 parts of a reinforcing filler, and 0-40 parts of a plasticizer; wherein, said branched polyethylene comprises an ethylene homopolymer having a degree of branching of not less than 50 branches/1000 carbon atoms, a weight average molecular weight of not less than 50,000, and a Mooney viscosity ML (1+4) at 125 C. of not less than 2.

2. The rubber composition according to claim 1, wherein, said branched polyethylene is an ethylene homopolymer, and if the content of said branched polyethylene in said rubber matrix is more than 90 parts, based on 100 parts by weight of said rubber matrix, said rubber composition comprises 6-40 parts of said plasticizer.

3. The rubber composition according to claim 2, wherein, if the content of said branched polyethylene in said rubber matrix is more than 90 parts, based on 100 parts by weight of said rubber matrix, said rubber composition comprises 10-30 parts of said plasticizer.

4. The rubber composition according to claim 1, wherein, said branched polyethylene is an ethylene homopolymer; and based on 100 parts by weight of said rubber matrix, the content of said branched polyethylene in said rubber matrix is represented as A, in which 10A100 parts, and the content of said EPM in said rubber matrix is represented as B and the content of said EPDM in said rubber matrix is represented as C, in which 0B+C90 parts, wherein, said branched polyethylene has a degree of branching of 60-130 branches/1000 carbon atoms, a weight average molecular weight of 66,000-518,000, and a Mooney viscosity ML (1+4) at 125 C. of 6-102.

5. The rubber composition according to claim 1, wherein, said rubber composition further comprises auxiliary components, which comprise, based on 100 parts by weight of said rubber matrix, 0.2 to 10 parts of an auxiliary crosslinking agent, 3 to 15 parts of a metal oxide, 1 to 3 parts of a stabilizer, 0.5 to 2 parts of stearic acid, 0.5 to 5 parts of polyethylene glycol, and 0 to 3 parts of a vulcanization accelerator, wherein, said stabilizer comprises at least one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), and 2-mercaptobenzimidazole (MB); said polyethylene glycol comprises at least one of those polyethylene glycol having a molecular weight of 2000, 3400, and 4000; said auxiliary crosslinking agent comprises at least one of triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, triallyl trimellitate, trimethylolpropane trimethacrylate, N,N-m-phenylene bismaleimide, N,N-bis(furfurylidene) acetone, 1,2-polybutadiene, a metal salt of an unsaturated carboxylic acid, and sulfur; said metal oxide comprises at least one of zinc oxide and magnesia; and said vulcanization accelerator comprises at least one of 2-mercaptobenzothiazole, dibenzothiazyl disulfide, tetramethyl thiuram monosulfide, tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, bismaleimide, and ethylene thiourea.

6. The rubber composition according to claim 1, wherein, said crosslinking agent comprises at least one of a peroxide crosslinking agent and sulfur, wherein, said peroxide crosslinking agent comprises at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 2,5 -dimethyl-2,5 -di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5 -di(tert-butylperoxy)hexyne-3, bis(tert-butylperoxyisopropyl)benzene, 2,5 -dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butylperoxy-2-ethylhexyl carbonate.

7. The rubber composition according to claim 1, wherein, said plasticizer comprises at least one of high-viscosity paraffin oil, liquid ethylene-propylene rubber, liquid polyisobutene, and liquid 1,2-polybutadiene.

8. The rubber composition according to claim 1, wherein, said reinforcing filler comprises at least one of carbon black N330, carbon black N550, carbon black N774, calcium carbonate, and talc.

9. (canceled)

10. A brake rubber hose, comprising an inner rubber layer, a middle rubber layer, and an outer rubber layer, wherein, the rubber compound used for at least one of said inner rubber layer, said middle rubber layer, and said outer rubber layer comprises said rubber composition according to claim 1.

11. (canceled)

12. A brake rubber diaphragm, wherein, the rubber compound used for said brake rubber diaphragm comprises said rubber composition according to claim 1.

13. (canceled)

Description

DETAILED DESCRIPTION

[0051] The following examples are given to further illustrate the present invention, and not intended to limit the scope of the present invention. Some non-essential improvements and modifications made by the skilled person in the art based on the disclosure herein are still within the scope of the present invention.

[0052] To more clearly illustrate the embodiments of the present invention, the materials involved in the present invention are defined below.

[0053] The crosslinking system includes a crosslinking agent, and also at least one of an auxiliary crosslinking agent and a vulcanization accelerator.

[0054] The materials used in the rubber matrix of the present invention are as follows.

[0055] The EPM useful in the rubber matrix of the present invention preferably has a Mooney viscosity ML (1+4) at 125 C. of 20-40 and preferably has an ethylene content of 45%-60%. The EPDM used preferably has a Mooney viscosity ML (1+4) at 125 C. of 25 to 50, and preferably has an ethylene content of 55% to 75%. The third monomer is 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene or dicyclopentadiene, and the content of the third monomer is 1%-7%.

[0056] The branched polyethylene can be obtained by the catalytic homopolymerization of ethylene in the presence of an (-diimine) nickel catalyst and a cocatalyst. The structure of the (-diimine) nickel catalyst used, the synthesis method and the method for preparing branched polyethylene therewith are disclosed in the prior art, as described in, without limitation, CN102827312A, CN101812145A, CN101531725A, CN104926962A, U.S. Pat. Nos. 6,103,658, and 6,660,677.

[0057] The branched polyethylene has a degree of branching of 60-130 branches/1000 carbon atoms, a weight average molecular weight of 66,000-518,000, and a Mooney viscosity ML (1+4) at 125 C. of 6-102. The degree of branching is measured by .sup.1H NMR, and the molar percentages of various branches are measured by .sup.13C NMR.

[0058] The details are shown in a table below:

TABLE-US-00001 Content of Weight Branched hexyl and average Mooney poly- Degree Methyl Ethyl Propyl Butyl Pentyl higher molecular Moleculear viscosity ethylene of content/ content/ content/ content/ content/ branches/ weight/ weight ML(1 + 4) No. branching % % % % % % 10,000 distribution at 125 C. PER-1 130 46.8 18.3 8.3 6.7 5.2 14.7 6.6 2.2 6 PER-2 116 51.2 17.6 8.2 5.8 5.1 12.1 20.1 2.1 23 PER-3 105 54.0 13.7 6.4 5.3 5.1 15.5 26.8 2.1 42 PER-4 102 56.2 12.9 6.2 5.2 4.9 14.6 27.9 2.1 52 PER-5 99 59.6 11.6 5.8 4.9 5.1 13.0 28.3 1.8 63 PER-6 90 62.1 9.4 5.4 4.6 4.5 14.0 32.1 2.1 77 PER-7 82 64.2 8.7 5.3 4.2 3.9 13.7 35.6 1.7 80 PER-8 70 66.5 7.2 4.6 3.2 3.2 15.3 43.6 2.1 93 PER-9 60 68.1 7.1 4.2 2.7 2.8 15.1 51.8 2.2 102 PER-10 102 56.8 12.7 6.1 5.2 5.1 13.9 34.8 1.9 66

Test Methods of Rubber Performances

[0059] 1. Hardness test: The test is carried out using a hardness tester at room temperature in accordance with the national standard GB/T 531.1-2008.

[0060] 2. Tensile strength and elongation at break performance test: The test is carried out with a type 2 dumbbell specimen using an electronic tensile tester at a tensile speed of 500 mm/min and a test temperature of 232 C. in accordance with the national standard GB/T528-2009.

[0061] 3. Tear resistance test: The test is carried out with a right-angled specimen using an electronic tensile tester at a tensile speed of 500 mm/min and a test temperature of 232 C. in accordance with the national standard GB/T529-2008.

[0062] 4. Mooney viscosity test: The test is carried out in accordance with the national standard GB/T1232.1-2000, with a Mooney viscosity meter at a test temperature of 125 C. by preheating for 1 minute, and the test is continued for 4 minutes.

[0063] 5. Compression set resistance test: The test is carried out with a Type B specimen using a compression set tester in accordance with the national standard GB/T7759-1996, where the compression rate is 25%, and the test temperature is 120 C.

[0064] 6. Hot air accelerated aging test: The test is carried out in a heat aging test chamber at 125 C. for 72 h in accordance with the national standard GB/T3512-2001.

[0065] 7. Test of resistance to DOT brake fluid: The test is carried out at 120 C. for 72 h in accordance with the national standard GB/T1690-2006.

[0066] 8. Test of optimum vulcanization time Tc90: The test is carried out at 170 C. in a rotorless vulcanizer in accordance with the national standard GB/T16584-1996.

[0067] The rubber composition used in the tests comprises, in parts by weight, 100 parts of a rubber matrix which comprises A parts of a branched polyethylene, in which 0<a100 parts, B parts of EPM, in which 0b<100 parts, and C parts of EPDM, in which 0c<100 parts; and further comprises, based on 100 parts by weight of the rubber matrix, 1.5 to 8 parts of a crosslinking agent, 40 to 140 parts of a reinforcing filler, and 0 to 40 parts of a plasticizer.

[0068] In a further embodiment, when the content of branched polyethylene in the rubber matrix is 90 parts, the content of the plasticizer is 6-40 parts based on 100 parts by weight of the rubber matrix, where the branched polyethylene has a degree of branching of 60-130 branches/1000 carbon atoms, a weight average molecular weight of 66,000-518,000, and a Mooney viscosity ML (1+4) at 125 C. of 6-102.

[0069] In a further embodiment, when the content of branched polyethylene in the rubber matrix is 90 parts, the content of the plasticizer is 10-30 parts based on 100 parts by weight of the rubber matrix.

[0070] The rubber composition further comprises auxiliary components, which comprise 0.2 to 10 parts of an auxiliary crosslinking agent, 3 to 15 parts of a metal oxide, 1 to 3 parts of a stabilizer, 0.5 to 2 parts of stearic acid, 0.5 to 5 parts of polyethylene glycol, and 0 to 3 parts of a vulcanization accelerator.

[0071] The stabilizer comprises at least one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), and 2-mercaptobenzimidazole (MB). The polyethylene glycol comprises at least one of those polyethylene glycol having a molecular weight of 2000, 3400, and 4000.

[0072] The auxiliary crosslinking agent comprises at least one of triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, triallyl trimellitate, trimethylolpropane trimethacrylate, N,N-m-phenylene bismaleimide, N,N-bis(furfurylidene) acetone, 1,2-polybutadiene, a metal salt of an unsaturated carboxylic acid, and sulfur.

[0073] The metal oxide comprises at least one of zinc oxide and magnesia. The vulcanization accelerator comprises at least one of 2-mercaptobenzothiazole, dibenzothiazyl disulfide, tetramethyl thiuram monosulfide, tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, bismaleimide, and ethylene thiourea.

[0074] The crosslinking agent includes at least one of a peroxide crosslinking agent and sulfur. The peroxide crosslinking agent includes at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butyl peroxide-3,3,5 -trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5 -dimethyl-2,5 -di(tert-butylperoxy)hexyne-3, bis(tert-butylperoxyisopropyl)benzene, 2,5 -dimethyl-2,5 -bis(benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butylperoxy-2-ethylhexyl carbonate.

[0075] The plasticizer comprises at least one of high-viscosity paraffin oil, liquid ethylene-propylene rubber, liquid polyisobutene, and liquid 1,2-polybutadiene. The liquid ethylene propylene rubber in the plasticizer is used as a plasticizer, and its content is not included in the rubber matrix.

[0076] The reinforcing filler includes at least one of carbon black N330, carbon black N550, carbon black N774, calcium carbonate, and talc.

[0077] The processing method for obtaining the rubber composition will be described below in conjunction with specific examples.

EXAMPLE 1

[0078] Branched polyethylene No. PER-3 was used.

[0079] The processing steps of the rubber composition were as follows.

[0080] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 50 parts of EPDM and 50 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. Then 70 parts of carbon black N550, and 10 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 4 parts of the crosslinking agent dicumyl peroxide (DCP) was added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0081] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 2

[0082] Branched polyethylene No. PER-3 was used.

[0083] The processing steps of the rubber composition were as follows.

[0084] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene was added, prepressed and mixed for 90 seconds. Then 70 parts of carbon black N550, and 10 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 4 parts of the crosslinking agent dicumyl peroxide (DCP) was added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0085] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 3

[0086] Branched polyethylene Nos. PER-3 and PER-6 were used.

[0087] The processing steps of the rubber composition were as follows.

[0088] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 70 parts of PER-3 and 30 parts of PER-6 were added, prepressed and mixed for 90 seconds. Then 70 parts of carbon black N550, and 10 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 4 parts of the crosslinking agent dicumyl peroxide (DCP) was added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours. (2) After vulcanization, various tests were carried out after standing for 16 hrs.

Comparative Example 1

[0089] The processing steps of the rubber composition were as follows.

[0090] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of EPDM was added, prepressed and mixed for 90 seconds. Then 70 parts of carbon black N550, and 10 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 4 parts of the crosslinking agent dicumyl peroxide (DCP) was added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours. (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 4

[0091] Branched polyethylene No. PER-9 was used.

[0092] The processing steps of the rubber composition were as follows.

[0093] (1) Rubber mixing: The temperature of the internal mixer was set to 100 C., and the rotor speed was set to 50 rpm. 90 parts of EPDM and 10 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0094] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 5

[0095] Branched polyethylene No. PER-7 was used.

[0096] The processing steps of the rubber composition were as follows.

[0097] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 20 parts of EPM, 50 parts of EPDM and 30 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0098] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 6

[0099] Branched polyethylene No. PER-3 was used.

[0100] The processing steps of the rubber composition were as follows.

[0101] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 30 parts of EPDM and 70 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0102] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

Example 7

[0103] Branched polyethylene Nos. PER-2 and PER-5 were used.

[0104] The processing steps of the rubber composition were as follows.

[0105] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 80 parts of PER-5 and 20 parts of PER-2 were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0106] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 8

[0107] Branched polyethylene Nos. PER-1 and PER-6 were used.

[0108] The processing steps of the rubber composition were as follows.

[0109] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 80 parts of PER-6 and 20 parts of PER-1 were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0110] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

Comparative Example 2

[0111] The processing steps of the rubber composition were as follows.

[0112] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of EPDM was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0113] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

[0114] The performance test data of Examples 1 to 8 and Comparative Examples 1 and 2 are shown in a table below.

TABLE-US-00002 Comparative Comparative Example Example Example Example Example Example Example Example Example Example Test Item 1 2 3 1 4 5 6 7 8 2 Hardness 74 73 75 75 77 74 73 74 75 74 Tensile 20.8 22.6 24.1 18.7 21.5 21.9 22.4 23.3 22.1 19.6 strength/ MPa Elongation 336 389 376 283 332 412 392 382 428 328 at break % Tear 34 39 45 31 36 37 38 47 43 32 strength N/mm Compression 33 30 30 37 37 37 33 29 31 39 set (at 120 C. for 24 h) After aging (at 125 C. for 72 h) Hardness 76 76 77 77 79 76 76 77 78 76 Retention 105 105 106 108 105 106 105 108 106 109 rate of tensile strength/% Retention 94 95 94 93 95 93 92 93 92 92 rate of elongation at break/% After aging in DOT4 (at 120 C. for 72 h) Hardness 72 71 73 72 74 72 71 72 72 70 Retention 105 105 103 104 104 105 102 103 104 102 rate of tensile strength/% Retention 93 94 94 95 93 92 91 92 92 91 rate of elongation at break/% Variation of +3 +4 +3 +4 +2 +2 +3 +2 +3 +2 volume/%

EXAMPLE 9

[0115] Branched polyethylene No. PER-5 was used.

[0116] The processing steps of the rubber composition were as follows.

[0117] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400 and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 80 parts of carbon black N550, and 30 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0118] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 10

[0119] Branched polyethylene No. PER-8 was used.

[0120] The processing steps of the rubber composition were as follows. (

[0121] 1) Rubber mixing: The temperature of the internal mixer was set to 100 C., and the rotor speed was set to 50 rpm. 80 parts of EPDM and 20 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. 3 parts of zinc oxide, 0.5 part of stearic acid, 1 part of polyethylene glycol PEG3400 and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 60 parts of carbon black N550, and 20 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 2 parts of the crosslinking agent dicumyl peroxide (DCP), 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC), and 0.2 part of the auxiliary crosslinking agent sulfur were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0122] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 11

[0123] Branched polyethylene No. PER-6 was used.

[0124] The processing steps of the rubber composition were as follows.

[0125] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 70 parts of EPDM and 30 parts of branched polyethylene were added, prepressed and mixed for 90 seconds. 3 parts of zinc oxide, 0.5 part of stearic acid, 0.5 part of polyethylene glycol PEG3400 and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 40 parts of carbon black N550 was added to the rubber compound, and mixed for 3 min. Finally, 1 part of the crosslinking agent dicumyl peroxide (DCP), 0.3 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC), 0.5 part of the crosslinking agent sulfur, 1 part of N-cyclohexyl-2-benzothiazole sulfenamide (CZ), and 0.8 part of tetramethyl thiuram disulfide (TMTD) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0126] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 12

[0127] Branched polyethylene Nos. PER-1, PER-2 and PER-6 were used.

[0128] The processing steps of the rubber composition were as follows.

[0129] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 10 parts of PER-1, 20 parts of PER-2 and 70 parts of PER-6 were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 0.5 part of polyethylene glycol PEG3400 and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 60 parts of carbon black N550, and 6 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP), 1 part of the auxiliary crosslinking agent triallyl isocyanurate (TAIC), and 0.3 part of the auxiliary crosslinking agent sulfur were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0130] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 13

[0131] Branched polyethylene Nos. PER-4 and PER-6 were used.

[0132] The processing steps of the rubber composition were as follows.

[0133] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 50 parts of PER-4 and 50 parts of PER-6 were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 1 part of stearic acid, 5 parts of polyethylene glycol PEG3400 and 2 parts of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 100 parts of carbon black N550, 20 parts of liquid ethylene-propylene rubber and 12 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 6 parts of the crosslinking agent dicumyl peroxide (DCP), 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC), and 8 parts of the auxiliary crosslinking agent 1,2-polybutadiene were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0134] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

EXAMPLE 14

[0135] Branched polyethylene Nos. PER-4 and PER-6 were used.

[0136] The processing steps of the rubber composition were as follows.

[0137] (1) Rubber mixing: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 50 parts of PER-4 and 50 parts of PER-6 were added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 2 parts of stearic acid, 5 parts of polyethylene glycol PEG3400 and 2 parts of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 140 parts of carbon black N550, 20 parts of liquid ethylene-propylene rubber and 20 parts of liquid polyisobutene were added to the rubber compound, and mixed for 3 min. Finally, 8 parts of the crosslinking agent dicumyl peroxide (DCP), 3 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC), and 0.3 parts of the auxiliary crosslinking agent sulfur were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill with a roll temperature of 60 C. to obtain a sheet having a thickness of about 2.5 mm, which was stood for 20 hours.

[0138] (2) After vulcanization, various tests were carried out after standing for 16 hrs.

[0139] The performance test data of Examples 9 to 14 are shown in a table below.

TABLE-US-00003 Example Example Example Example Example Example Test Item 9 10 11 12 13 14 Hardness 75 77 75 75 76 78 Tensile strength/MPa 24.9 20.7 24.3 24.8 23.7 24.3 Elongation at break % 489 375 388 432 386 355 Tear strength N/mm 46 37 39 42 41 43 Compression set (at 29 36 34 31 33 32 120 C. for 24 h) After aging (at 125 C. for 72 h) Hardness 78 80 78 77 77 80 Retention rate of 97 106 94 107 109 109 tensile strength/% Retention rate of 92 93 83 92 93 89 elongation at break/% After aging in DOT4 (at 120 C. for 72 h) Hardness 72 74 73 73 74 74 Retention rate of 105 102 92 103 104 102 tensile strength/% Retention rate of 91 93 87 91 92 88 elongation at break/% Variation of volume/% +1 +3 +3 +3 +2 +1

[0140] Specific embodiments of the present invention further include use of the rubber composition mainly in the production of brake rubber diaphragms and brake rubber hoses, and the specific embodiments are as follows:

EXAMPLE 15

[0141] The present invention provides a brake rubber hose having an inner rubber layer using the rubber composition, and the brake rubber hose comprises the inner rubber layer, a first knitted layer, a middle rubber layer, a second knitted layer and an outer rubber layer. The production method comprises the following steps:

[0142] (1) Rubber mixing: The formulation and mixing process of the inner rubber layer were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-5 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400 and 1 part of the anti-aging agent RD were then added. Then 80 parts of carbon black N550, and 30 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0143] (2) Extrusion molding

[0144] An inner rubber layer was extruded on a mandrel at 90 C. by using a 60 mm cold feed extruder equipped with a T-slot die; then a layer was knitted with vinylon; next, a middle rubber layer was extruded; then a layer was knitted with vinylon again; and an outer rubber layer was extruded to obtain a hose blank, which was vulcanized, cooled, removed from the mandrel, trimmed, inspected, and stored, where the vulcanization process was steam vulcanization at 160 C. for 30 min under a steam pressure of 0.6 MPa.

EXAMPLE 16

[0145] The present invention provides a brake rubber hose having an inner rubber layer and an outer rubber layer using the rubber composition, and the brake rubber hose comprises the inner rubber layer, a first knitted layer, a middle rubber layer, a second knitted layer and the outer rubber layer. The production method comprises the following steps:

[0146] (1) Rubber mixing: The formulations and mixing processes of the inner rubber layer and the outer rubber layer of the brake rubber hose were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-5 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400 and 1 part of the anti-aging agent RD were then added. Then 80 parts of carbon black N550, and 30 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0147] (2) Extrusion molding: An inner rubber layer was extruded on a mandrel at 90 C. by using a 60 mm cold feed extruder equipped with a T-slot die; then a layer was knitted with vinylon; next, a middle rubber layer was extruded; then a layer was knitted with vinylon again; and an outer rubber layer was extruded to obtain a hose blank, which was vulcanized, cooled, removed from the mandrel, trimmed, inspected, and stored, where the vulcanization process was steam vulcanization at 160 C. for 30 min under a steam pressure of 0.6 MPa.

EXAMPLE 17

[0148] The present invention provides a brake rubber hose having an inner rubber layer, a middle rubber layer and an outer rubber layer using the rubber composition, and the brake rubber hose comprises the inner rubber layer, a first knitted layer, the middle rubber layer, a second knitted layer and the outer rubber layer. The production method comprises the following steps:

[0149] (1) Rubber mixing: The formulations and mixing processes of the rubber layers were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-5 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400 and 1 part of the anti-aging agent RD were then added.

[0150] Then 80 parts of carbon black N550, and 30 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0151] (2) Extrusion molding

[0152] An inner rubber layer was extruded on a mandrel at 90 C. by using a 60 mm cold feed extruder equipped with a T-slot die; then a layer was knitted with vinylon; next, a middle rubber layer was extruded; then a layer was knitted with vinylon again; and an outer rubber layer was extruded to obtain a hose blank, which was vulcanized, cooled, removed from the mandrel, trimmed, inspected, and stored, where the vulcanization process was steam vulcanization at 160 C. for 30 min under a steam pressure of 0.6 MPa.

EXAMPLE 18

[0153] The present invention provides a brake rubber hose having an outer rubber layer using the rubber composition, and the brake rubber hose comprises an inner rubber layer, a knitted layer, a middle rubber layer, a knitted layer and the outer rubber layer. The production method comprises the following steps:

[0154] (1) Rubber mixing:

[0155] The formulations and mixing processes of the rubber layers were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-5 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400 and 1 part of the anti-aging agent RD were then added. Then 80 parts of carbon black N550, and 30 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0156] (2) Extrusion molding

[0157] An inner rubber layer was extruded on a mandrel at 90 C. by using a 60 mm cold feed extruder equipped with a T-slot die; then a layer was knitted with vinylon; next, a middle rubber layer was extruded; then a layer was knitted with vinylon again; and an outer rubber layer was extruded to obtain a hose blank, which was vulcanized, cooled, removed from the mandrel, trimmed, inspected, and stored, where the vulcanization process was steam vulcanization at 160 C. for 30 min under a steam pressure of 0.6 MPa.

EXAMPLE 19

[0158] A method for producing a brake fluid resistant brake rubber diaphragm comprises the following steps:

[0159] (1) Mixing and molding: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-5 was added, prepressed and mixed for 90 seconds. 15 parts of zinc oxide, 2 parts of stearic acid, 1 part of polyethylene glycol PEG3400 and 1 part of the anti-aging agent 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD) were then added. Then 60 parts of carbon black N762, and 10 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent trimethylolpropane trimethacrylate (TMPTMA) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded, stood and inspected. The sheet was remilled, weighed and molded.

[0160] (2) Vulcanization: After mold vulcanizing, cooling, trimming, and inspecting, a finished product was obtained, where the vulcanization temperature was 160 C., the steam pressure was 0.6 MPa, and the vulcanization time was 25 minutes.

EXAMPLE 20

[0161] A method for producing a brake fluid resistant brake rubber diaphragm comprises the following steps:

[0162] (1) Mixing and molding: The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-10 was added, prepressed and mixed for 90 seconds. 15 parts of zinc oxide, 2 parts of stearic acid, 1 part of polyethylene glycol PEG3400 and 1 part of the anti-aging agent MB were then added. Then 60 parts of carbon black N762, and 10 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 3 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent trimethylolpropane trimethacrylate (TMPTMA) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded, stood and inspected. The sheet was remilled, weighed and molded.

[0163] (2) Vulcanization: After mold vulcanizing, cooling, trimming, and inspecting, a finished product was obtained, where the vulcanization temperature was 160 C., the steam pressure was 0.6 MPa, and the vulcanization time was 25 minutes.

EXAMPLE 21

[0164] The present invention provides a brake rubber hose comprising an inner rubber layer, a first knitted layer, a middle rubber layer, a second knitted layer and an outer rubber layer. The production method comprises the following steps:

[0165] (1) Rubber mixing:

[0166] The formulation and mixing process of the inner rubber layer were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-10 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400, 1 part of the anti-aging agent RD, and 1 part of the anti-aging agent MB were then added. Then 50 parts of carbon black N774, 5 parts of liquid polyisobutene and 5 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0167] The formulation and mixing process of the middle rubber layer were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-10 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol

[0168] PEG3400, 3 parts of coumarone resin, 2 parts of RX-80, 1 part of the anti-aging agent RD, and 1 part of the anti-aging agent MB were then added. Then 50 parts of carbon black N774, 5 parts of liquid polyisobutene and 5 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0169] The formulation and mixing process of the outer rubber layer were as follows. The temperature of the internal mixer was set to 90 C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene PER-10 was added, prepressed and mixed for 90 seconds. 5 parts of zinc oxide, 0.5 part of stearic acid, 2 parts of polyethylene glycol PEG3400, 1 part of the anti-aging agent RD, and 1 part of the anti-aging agent MB were then added. Then 80 parts of carbon black N774, 15 parts of liquid polyisobutene and 15 parts of liquid ethylene-propylene rubber were added to the rubber compound, and mixed for 3 min. Finally, 5 parts of the crosslinking agent dicumyl peroxide (DCP) and 2 parts of the auxiliary crosslinking agent triallyl isocyanurate (TAIC) were added, mixed for 2 min, and then discharged. The rubber mix was plasticated on an open mill to obtain a sheet which was then unloaded and stood for 24 hours.

[0170] (2) Extrusion molding

[0171] An inner rubber layer was extruded on a mandrel at 90 C. by using a 60 mm cold feed extruder equipped with a T-slot die; then a layer was knitted with vinylon; next, a middle rubber layer was extruded; then a layer was knitted with vinylon again; and an outer rubber layer was extruded to obtain a hose blank, which was vulcanized, cooled, removed from the mandrel, trimmed, inspected, and stored, where the vulcanization process was steam vulcanization at 160 C. for 30 min under a steam pressure of 0.6 MPa.