AGEING-RESISTANT RUBBER COMPOSITION AND PROCESSING METHOD THEREFOR AND USE THEREOF

Abstract

Disclosed are an aging-resistant rubber composition and a processing method therefor and use thereof. The rubber composition includes a rubber matrix and compounding components, and in parts by weight, every 100 parts of said rubber matrix comprise 50-99 parts of a halogenated butyl rubber, 0-50 parts of a highly branched polyethylene P1, and 0-50 parts of P2 obtained by the polarization modification of said highly branched polyethylene P1, and the sum of P1 and P2 in parts by weight is 1-50 parts; and said compounding components comprise a vulcanization system. The rubber composition improves the heat aging resistance of the halogenated butyl rubber, making it more suitable for high temperature environments, and also improves the properties of the halogenated butyl rubber which are related to the halogen content, such as the adhesiveness, oil resistance, flame retardancy and the like, by adjusting the extent of halogenation of the highly branched polyethylene which is employed in combination, thereby overcoming the limitation caused by the halogen content of the halogenated butyl rubber.

Claims

1. A rubber composition, comprising a rubber matrix and compounding components, wherein, in parts by weight, every 100 parts of said rubber matrix comprise 50-99 parts of a halogenated butyl rubber, 0-50 parts of a highly branched polyethylene P1, and 0-50 parts of P2 obtained by the polarization modification of said highly branched polyethylene P1, and the sum of P1 and P2 in parts by weight is 1-50 parts; and said compounding components comprise a vulcanization system.

2. The rubber composition according to claim 1, wherein, said P1 is an ethylene homopolymer having a branching degree of not less than 50 branches/1000 carbon atoms.

3. The rubber composition according to claim 2, wherein, the branching degree of said P1 is 60-130 branches/1000 carbon atoms.

4. The rubber composition according to claim 3, wherein the branching degree of the P1 is 72-112 branches/1000 carbon atoms.

5. The rubber composition according to claim 1, wherein, the polar monomer used for preparing said P2 comprises at least one of maleic anhydride (MAH), methacrylic acid (MA), acrylic acid (AA), itaconic acid (IA), fumaric acid (FA), isocyanate, glycidyl methacrylate (GMA), methyl methacrylate (MMA), dibutyl fumarate (DBF), β-hydroxyethyl methacrylate (HEMA), dibutyl maleate (DBM), diethyl maleate (DEM), elemental halogen, a halogen-containing compound, a sulfur-containing compound, vinyltrimethoxysilane (VTMS), vinyltriethoxysilane (VTES), 3-methacryloxypropyltrimethoxysilane (VMMS), styrene (St), α-methylstyrene (α-MSt), and acrylonitrile (AN).

6. The rubber composition according to claim 5, wherein, said P2 is a halogen-containing branched polyethylene with a polar group which comprises at least one of a chlorine group, a bromine group, a chlorosulfonyl group, and a bromosulfonyl group.

7. The rubber composition according to claim 6, wherein, the mass percentage of halogen in said halogen-containing branched polyethylene is 0.2-50%, and said halogen-containing branched polyethylene comprises at least one of chlorinated branched polyethylene, brominated branched polyethylene, and chlorosulfonated branched polyethylene.

8. The rubber composition according to claim 7, wherein, the mass percentage of chlorine in said chlorinated branched polyethylene or said chlorosulfonated branched polyethylene is 0.5-45.5%, and the mass percentage of bromine in said brominated branched polyethylene is 0.8-4%.

9. The rubber composition according to claim 1, wherein, based on 100 parts by weight of said rubber matrix, said rubber composition further comprising 0-30 parts of an ethylene propylene diene monomer rubber.

10. The rubber composition according to claim 1, wherein, said vulcanization system is selected from at least one of a peroxide vulcanization system, a sulfur vulcanization system, a thiourea vulcanization system, a metal oxide vulcanization system, and a radiation vulcanization sensitization system.

11. The rubber composition according to claim 10, wherein, said vulcanization system is a peroxide vulcanization system, and based on 100 weight parts of said rubber matrix, the usage amount of peroxides is 1-10 weight parts, and a peroxide crosslinking agent is at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peroxybenzoate, and tert-butylperoxy-2-ethylhexyl carbonate.

12. The rubber composition according to claim 11, wherein, said peroxide vulcanization system further comprises 0.2-20 parts by weight of an auxiliary crosslinking agent, and 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, an unsaturated carboxylic acid metal salt, and sulfur.

13. The rubber composition according to claim 1, wherein, based on 100 parts by weight of said rubber matrix, said compounding components further comprise 10-200 parts of a reinforcing filler, 0-80 parts of a plasticizer, 3-30 parts of a metal oxide, 0-3 parts of stearic acid, 0-15 parts of a surface modifier, 0-6 parts of a stabilizer, 0-15 parts of a tackifier, 0-20 parts of an adhesive, 0-150 parts of a flame-retardant agent, 0-20 parts of a foaming agent, and 0-40 parts of an air-blocking agent.

14. A conveyor belt, comprising a covering rubber layer for working surface, a covering rubber layer for non-working surface, and a tensile layer provided between said covering rubber layer for working surface and said covering rubber layer for non-working surface, wherein, the rubber used for at least one of said covering rubber layer for working surface and said covering rubber layer for non-working surface comprises said rubber composition according to claim 1.

15. (canceled)

16. A tire, comprising an inner liner, wherein, the rubber used in said inner liner comprises said rubber composition according to claim 1.

Description

DETAILED DESCRIPTION

[0058] 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.

[0059] The branched polyethylene raw materials used in examples are characterized by preferably having a branching degree of 50-130 branches/1000 carbon atoms, a weight average molecular weight of 6.6×10.sup.4-53.4×10.sup.4 g/mol, and a Mooney viscosity ML (1+4) at 125° C. of 6-105. The branching degree is measured by .sup.1H-NMR, and the molar percentages of various branches are measured by .sup.13C NMR.

[0060] The branched polyethylene raw materials are further preferably selected from the following table:

TABLE-US-00001 Weight Mooney Hexyl and average viscosity Branched longer molecular Molecular ML polyethylene Branching Methyl Ethyl Propyl Butyl Pentyl branch weight/ weight (1 + 4) No. degree content/% content/% content/% content/% content/% content/% ×10,000 distribution 125° C. PER-1 130 46.8 18.3 8.3 6.7 5.2 14.7 6.6 2.2 6 PER-2 120 49.2 17.9 8.2 6.1 5.1 13.5 8.2 2.1 12 PER-3 112 52.4 16.2 7.6 5.6 4.9 13.3 22.5 1.9 32 PER-4 105 54.0 13.7 6.4 5.3 5.1 15.5 26.8 2.1 42 PER-5 102 56.2 12.9 6.2 5.2 4.9 14.6 27.9 2.1 52 PER-6 99 59.6 11.6 5.8 4.9 5.1 13.0 28.3 1.8 63 PER-7 97 60.5 10.8 5.7 4.7 4.9 13.3 34.8 2.0 65 PER-8 90 62.1 9.4 5.4 4.6 4.5 14.0 32.1 2.1 77 PER-9 82 64.2 8.7 5.3 4.2 3.9 13.7 35.6 1.7 80 PER-10 72 67.1 6.2 3.7 4.1 3.3 15.6 15.8 1.9 20 PER-11 70 66.5 7.2 4.6 3.2 3.2 15.3 43.6 2.1 93 PER-12 60 68.1 7.1 4.2 2.7 2.8 15.1 51.8 2.2 102 PER-13 50 69.2 7.1 3.9 2.5 2.6 14.7 53.4 2.3 105

[0061] The preparation method for the halogen-containing branched polyethylene used in the examples of the present invention was prepared by introducing chlorine gas, bromine, or sulfur dioxide into a carbon tetrachloride or hexane solution containing a branched polyethylene and a free radical initiator (such as azobisisobutyronitrile), and controlling different reaction temperatures and times, to obtain different halogen-containing branched polyethylenes. The halogen-containing branched polyethylene used in the examples of the present invention is selected from the following table:

TABLE-US-00002 Branched poly- Mass Mass Mass ethylene raw percentage percentage percentage P2 No. materials No. of Chlorine/% of Bromine/% of Sulfur/% P2-1 PER-5 0.5 P2-2 PER-5 1.2 P2-3 PER-5 1.9 P2-4 PER-5 3.1 P2-5 PER-5 6.3 P2-6 PER-5 10.4 P2-7 PER-8 1 P2-8 PER-5 1.5 P2-9 PER-4 1.9 P2-10 PER-7 2.1 P2-11 PER-8 3.2 P2-12 PER-10 6.2 P2-13 PER-5 15.3 P2-14 PER-4 23.8 P2-15 PER-4 35.6 P2-16 PER-4 45.5 P2-17 PER-3 36.1 1

[0062] The halogenated butyl rubber used in the examples of the present invention may be selected from the following table:

TABLE-US-00003 Mass Mass Mooney Halogenated butyl percentage percentage viscosity rubber No. of Chlorine/% of Bromine/% ML (1 + 8) 125° C. CIIR-1 1.2 38 CIIR-2 1.2 50 BIIR-1 2 32 BIIR-2 2 46

[0063] Rubber Performance Test Methods:

[0064] 1. Hardness test: The test is carried out by using a hardness tester at room temperature in accordance with the national standard GB/T531.1-2008.

[0065] 2. Tensile strength and elongation at break performance test: The test is carried out with a type 2 dumbbell sample by using an electronic tensile tester at a tensile speed of 500 mm/min and a test temperature of 23±2° C. in accordance with the national standard GB/T528-2009.

[0066] 3. Mooney viscosity test: The test is carried out with a Mooney viscosity meter in accordance with the national standard GB/T1232.1-2000, at a test temperature set according to the actual conditions, by preheating for 1 minute, and the test is continued for 4-8 minutes.

[0067] 4. Hot air accelerated aging test: The test is carried out in a heat aging test chamber in accordance with the national standard GBAT3512-2001, at a temperature and for the time set according to the actual conditions.

[0068] 5. Air tightness test: The gas barrier test is carried out by using an air tightness tester in accordance with the national standard GB7755.

Examples 1-6 and Comparative Example 1

[0069] The present invention provides a rubber composition with a good heat resistance and wear resistance, which is suitable for the applications such as a heat-resistant conveyor belt that have requirements for the heat resistance and wear resistance. Examples 1-6 and Comparative Example 1 are used as examples. The basic compositions of Examples 1-6 and Comparative Example 1 are shown in Table 1:

TABLE-US-00004 TABLE 1 Comparative Example Example Example Example Example Example Component Example 1 2 3 4 5 6 Halogenated butyl BIIR-2 BIIR-2 BIIR-2 BIIR-2 BIIR-2 CIIR-2 CIIR-2 rubber No. Amount of 100 90 80 70 75 60 50 Halogenated butyl rubber P1 No. PER-3 PER-4 PER-5 PER-10 Amount of P1 10 20 30 20 P2 No. P2-10 P2-12 P2-13 Amount of P2 25 20 50 Zinc oxide 5 5 5 5 5 5 5 Magnesium oxide 1 1 1 1 1 1 1 Stearic acid 1 1 1 1 1 1 1 Anti-aging agent RD 1 1 1 1 1 1 1 Polyethylene glycol 2 2 2 2 2 2 2 PEG4000 Carbon black N330 50 50 50 50 50 50 50 Paraffin oil 10 10 10 10 10 10 10 Sunpar2280 DCP 1 1.2 1.4 1.6 1.5 2 2 HVA-2 2 2 2 2 2 1.5 1.5 TAIC 0.3 0.5 0.5 0.5 0.6 0.6 Sulfur 0.1 0.1 0.1 0.2 0.2

[0070] The rubber compositions of Examples 1-6 and Comparative Example 1 were mixed according to the following method:

[0071] The internal mixer was set to a temperature of 70° C. and a rotor speed of 40 rpm. The rubber matrix was added, prepressed, and mixed for 90 seconds. Magnesium oxide, stearic acid, anti-aging agent RD, and polyethylene glycol PEG4000 were then added and mixed for 1 minute. Carbon black and paraffin oil were then added and mixed for 2 minutes. Finally, the remaining components were added and mixed for 2 minutes, and then a rubber mix was discharged. The rubber mix was plasticated on an open mill to a sheet, unloaded, and stood for 24 hours.

[0072] The sheet was remixed and discharged. The samples used in the Tensile and DIN wear tests were prepared according to the test standards and tested after stood for 20 hours.

[0073] The performance test results of Examples 1-6 and Comparative Example 1 were shown in Table 2:

TABLE-US-00005 Comparative Example Example Example Example Example Example Test items Example 1 2 3 4 5 6 Hardness (Shore A) 52 51 53 55 56 58 59 Tensile strength/MPa 12.1 12.4 14.2 16.7 17.5 18.4 18.6 Elongation at break/% 428 445 462 478 469 442 431 Relative wear volume as 281 263 237 188 172 145 138 per DIN/mm.sup.3 After aging (150° C. × 70 h) Hardness (Shore A) 53 52 54 56 57 58 59 Retention rate of tensile 76 79 82 84 84 85 86 strength/% Retention rate of 63 68 70 75 72 76 78 elongation at break/%

[0074] Through comparison, it may be found that the mechanical properties, heat aging resistance and wear resistance of the rubber composition were improved after being used in combination with the highly branched polyethylene and/or the halogenated highly branched polyethylene.

Examples 7-13 and Comparative Example 2

[0075] The present invention provides a rubber composition with a good heat resistance and air tightness, which is suitable for the applications such as a tire inner-liner or an inner tube that have requirements for the air tightness. Examples 7-13 and Comparative Example 2 are used as examples. The basic compositions of Examples 7-13 and Comparative Example 2 are shown in Table 3:

TABLE-US-00006 TABLE 3 Comparative Example Example Example Example Example Example Example Component Example 2 7 8 9 10 11 12 13 Halogenated butyl BIIR-1 BIIR-1 BIIR-1 BIIR-1 BIIR-1 BIIR-1 BIIR-1 BIIR-1 rubber No. Amount of 100 95 90 85 75 70 60 50 Halogenated butyl rubber P2 No. P2-9 P2-14 P2-15 P2-15 P2-17 P2-17 P2-17 Amount of P2 5 10 15 25 30 40 50 Zinc oxide 3 3 3 3 3 3 3 3 Magnesium oxide 1 1 1 1 2 2 3 3 Stearic acid 1 1 1 1 1 1 1 1 SP-1068 3 3 3 3 3 3 3 3 Escorez 1102 5 5 5 5 5 5 5 5 Carbon black N660 60 60 60 60 60 60 60 60 Paraffin oil 8 8 8 8 8 8 8 8 Sunpar2280 Sulfur 0.5 0.5 0.5 0.4 0.4 0.35 0.3 0.3 Accelerator DM 1.5 1.4 1.4 1.2 1.2 1.2 1 1 DCP 0.2 0.4 0.8 1 1.2 1.4 1.6 TAIC 0.1 0.2 0.5 0.5 0.6 0.7 0.8 Air-blocking agent 20 20 NM360

[0076] The rubber compositions of Examples 7-13 and Comparative Example 2 were mixed according to the following method:

[0077] The internal mixer was set to a temperature of 70° C. and a rotor speed of 40 rpm. The rubber matrix was added, prepressed, and mixed for 90 seconds. Magnesium oxide, stearic acid, SP-1068, and Escorez1102 were then added and mixed for 1 minute. Carbon black, air-blocking agent (if any), and paraffin oil were then added and mixed for 2 minutes. Finally, the remaining components were added and mixed for 2 minutes, and then a rubber mix was discharged. The rubber mix was plasticated on an open mill to a sheet, unloaded, and stood for 24 hours.

[0078] The sheet was remixed and discharged. The samples used in the Tensile and air tightness tests were prepared according to the test standards and tested after stood for 20 hours.

[0079] The performance test results of Examples 7-13 and Comparative Example 2 were shown in Table 4:

TABLE-US-00007 TABLE 4 Comparative Example Example Example Example Example Example Example Performance test Example 2 7 8 9 10 11 12 13 Tensile strength/MPa 10.7 11.1 11.7 12 12.8 13.3 14.8 15.3 Elongation at break/% 810 753 720 683 661 652 624 618 Air permeability 0.25 0.25 0.26 0.26 0.27 0.27 0.23 0.24 coefficient/10.sup.−17m.sup.−2(s .Math. Pa).sup.−1 (25° C., nitrogen) After aging (125° C. × 72 h) Retention rate of tensile 84 84 87 88 89 89 91 91 strength/% Retention rate of 71 73 75 76 78 80 78 81 elongation at break/%

[0080] Through comparison, it may be found that the rubber composition of the present invention may have an air permeability equivalent to that of the perhalogenated butyl rubber, but the mechanical strength and heat resistance are significantly improved, making it possible to have a better tolerance to the working conditions of high-temperature carcasses.

[0081] Although preferred embodiments of the present invention have been described herein, these embodiments are provided merely by way of examples. It is to be understood that variations of the embodiments of the present invention described herein can also be used in the practice of the present invention. It will be appreciated by those skilled in the art that various modifications, changes and substitutions can be made without departing from the scope of the present invention. It is to be understood that the scope of the present invention is defined by the appended claims, and the methods, structures, and equivalents thereof within the scope of the claims are also contemplated in the scope of the claims.