Photo-crosslinked rubber composition, and rubber product using the same

Abstract

The present invention discloses a photo-crosslinked rubber composition and application thereof. The rubber composition comprises a rubber matrix and an initiator. Based on 100 parts by weight of the rubber matrix, the rubber matrix comprises a branched polyethylene with a content represented as A, in which 0<A≤100, and an ethylene-propylene rubber with a content represented as B, in which 0≤B<100; and the initiator accounts for 0.1-10 parts, and the initiator includes at least one of a cationic photoinitiator and a free radical photoinitiator. In the rubber composition, the ethylene-propylene rubber is partially or completely replaced by the branched polyethylene. The rubber composition can be used for rubber product crosslinked by ultraviolet light, including wire, cable, film, glove, condom, and medical catheter, which achieves excellent elasticity, electrical insulation property, aging resistance and ozone resistance, and also has good mechanical strength.

Claims

1. A rubber composition, comprising a rubber matrix and an initiator, wherein, based on 100 parts by weight of the rubber matrix, the rubber matrix comprises a branched polyethylene with a content represented as A, in which 0<A≤100, and an ethylene-propylene rubber with a content represented as B, in which 0≤B<100; based on 100 parts by weight of the rubber matrix, the initiator accounts for 0.1-10 parts, and the initiator includes at least one of a cationic photoinitiator and a free radical photoinitiator, wherein the branched polyethylene is an ethylene homopolymer having a degree of branching of from 60 to 105 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 the content of the initiator is 0.5-5 parts, based on 100 parts by weight of the rubber matrix.

3. The rubber composition according to claim 1, wherein the cationic photoinitiator comprises at least one of an aromatic diazonium salt, a diaryliodonium salt, a triarylsulfonium salt, an alkylsulfonium salt, a ferrocene salt, a sulfonyloxyketone and a triarylsiloxane, and the triarylsulfonium salt is triarylsulfonium hexafluorophosphate.

4. The rubber composition according to claim 1, wherein the free radical photoinitiator comprises at least one of an intramolecular cleavage type photoinitiator and an intermolecular hydrogen abstraction type photoinitiator, and the intramolecular cleavage type photoinitiator or the intermolecular hydrogen abstraction type photoinitiator is at least one of benzophenone, diphenylethanone, dialkoxyacetophenone, benzoin dimethyl ether, α-hydroxyisobutyrylbenzene, acylphosphine oxide, benzoin isopropyl ether, benzoin n-butyl ester, anthraquinone, and fluorenone.

5. The rubber composition according to claim 1, wherein the rubber composition further comprises auxiliary components, and based on 100 parts by weight of the rubber matrix, the auxiliary components comprise 0.1-5 parts of a crosslinking agent, 0.01-2 parts of an antioxidant, 3-25 parts of a plasticizer, 0-10 parts of a metal oxide, 0-200 parts of an inorganic filler, and 0.3-5 parts of a coupling agent.

6. The rubber composition according to claim 5, wherein the crosslinking agent comprises at least one of triallyl cyanurate, triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triallyl ether, and pentaerythritol ester tetraallyl ether.

7. The rubber composition according to claim 5, wherein the plasticizer comprises at least one of polyethylene wax, pine tar, motor oil, aromatic oil, naphthenic oil, paraffin oil, microcrystalline wax, and coumarone resin; the metal oxide comprises at least one of zinc oxide, magnesium oxide, calcium oxide, lead monoxide, and lead tetraoxide; the inorganic filler comprises at least one of silica, calcium carbonate, talcum powder, calcined clay, magnesium silicate, magnesium carbonate, aluminum hydroxide, and magnesium hydroxide; the coupling agent comprises at least one of vinyl tris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane; the antioxidant comprises at least one of 2,6-di-tert-butylphenol, 2,4,6-tri-tert-butylphenol, 4,4′-thiobis(6-tert-butyl-3-methylphenol), triphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, triisooctyl phosphite, tricresyl phosphate, pentaerythritol tetrakis(3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate), dilauryl thiodipropionate, lauryl-stearyl thiodipropionate, and ditridecyl 3,3′-thiodipropionate.

8. The rubber composition according to claim 1, wherein based on 100 parts by weight of the rubber matrix, the rubber matrix comprises a branched polyethylene with a content represented as A, in which 10≤A≤100, said ethylene-propylene rubber is consisted of EPM and EPDM, and the EPM and EPDM with a total content represented as B, in which 0≤B≤90; and the branched polyethylene is characterized by having a degree of branching of from 80 to 105 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.

9. A wire, comprising a conductor layer and an insulating layer, wherein, said insulating layer comprises a rubber compound according to claim 1.

10. A cable, comprising a conductor layer, an insulating layer and a sheathing layer, wherein, said insulating layer and sheathing layer comprises a rubber compound according to claim 1.

11. A photo-crosslinked rubber product, wherein, the rubber compound used for said photo-crosslinked rubber product comprises said rubber composition according to claim 1.

12. The photo-crosslinked rubber product according to claim 11, wherein, said photo-crosslinked rubber product is a medical catheter.

13. The photo-crosslinked rubber product according to claim 11, wherein, said photo-crosslinked rubber product is a condom.

14. The photo-crosslinked rubber product according to claim 11, wherein, said photo-crosslinked rubber product is a glove.

Description

DETAILED DESCRIPTION

(1) The present invention is further described through examples, but such examples are not intended to limit the scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention shall also fall within the protection scope of the present invention.

(2) The specific examples of a rubber polymer provided by the present invention are as follows: a formulation of a rubber composition comprises a rubber matrix and an initiator, the rubber matrix comprises a branched polyethylene with a content represented as A, in which 0<A≤100, and an ethylene-propylene rubber with a content represented as B, in which 0≤B<100; and based on 100 parts by weight of the rubber matrix, the content of the initiator is 0.1-10 parts, preferably 0.5-5 parts. The initiator includes at least one of a cationic photoinitiator and a free radical photoinitiator. The branched polyethylene has 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.

(3) The preferred 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 initiator includes at least one of a cationic photoinitiator and a free radical photoinitiator.

(4) The cationic photoinitiator includes at least one of an aromatic diazonium salt, a diaryliodonium salt, a triarylsulfonium salt, an alkylsulfonium salt, a ferrocene salt, a sulfonyloxyketone and a triarylsiloxane, specifically at least one of triarylsulfonium hexafluorophosphate, ferrocene hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and didodecylbenzeneiodonium hexafluoroarsenate.

(5) The free radical photoinitiator includes at least one of an intramolecular cleavage type photoinitiator and an intermolecular hydrogen abstraction type photoinitiator, specifically at least one of benzophenone, diphenylethanone, dialkoxyacetophenone, benzoin dimethyl ether, α-hydroxyisobutyrylbenzene, acylphosphine oxide, benzoin isopropyl ether, benzoin n-butyl ester, anthraquinone, and fluorenone.

(6) The rubber composition also comprises auxiliary components, and based on 100 parts by weight, the auxiliary components include 0.1-5 parts of a crosslinking agent, 0.01-2 parts of an antioxidant, 3-25 parts of a plasticizer, 0-10 parts of metal oxide, 0-200 parts of an inorganic filler, and 0.3-5 parts of a coupling agent. The crosslinking agent includes at least one of triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), pentaerythritol triallyl ether, and pentaerythritol ester tetraallyl ether.

(7) The plasticizer includes at least one of polyethylene wax, pine tar, motor oil, aromatic oil, naphthenic oil, paraffin oil, microcrystalline wax, and coumarone resin.

(8) The metal oxide includes at least one of zinc oxide, magnesium oxide, calcium oxide, lead monoxide, and lead tetraoxide.

(9) The inorganic filler includes at least one of silica, calcium carbonate, talcum powder, calcined clay, magnesium silicate, magnesium carbonate, aluminum hydroxide, and magnesium hydroxide.

(10) The coupling agent includes at least one of vinyl tris(2-methoxyethoxy)silane (A-172), 3-glycidoxypropyltrimethoxysilane (A-187), γ-mercaptopropyltrimethoxysilane (A-189), and 3-methacryloxypropyltrimethoxysilane (KH570). The antioxidant includes at least one of 2,6-di-tert-butylphenol, 2,4,6-tri-tert-butylphenol, 4,4′-thiobis(6-tert-butyl-3-methylphenol), triphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168), triisooctyl phosphite, tricresyl phosphate, pentaerythritol tetrakis(3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate) (antioxidant 1010), dilauryl thiodipropionate (DLTP), lauryl-stearyl thiodipropionate, and ditridecyl 3,3′-thiodipropionate.

(11) In the present invention, the EPM and the EPDM used preferably have a Mooney viscosity ML (1+4) at 125° C. of 50-80, and preferably an ethylene content of 50%-70%. The third monomer used is 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene or dicyclopentadiene, and the content of the third monomer is 1%-7%.

(12) The branched polyethylene can be obtained by catalyzing homopolymerization of ethylene in the presence of an (α-diimine) nickel catalyst and a cocatalyst. The structure of the (α-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.

(13) The branched polyethylene used is characterized by having 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.

(14) The details are shown in a table below:

(15) TABLE-US-00001 Weight average Mooney Branched Hexyl or molecular Molecular viscosity polyethylene Degree of Methyl/ Ethyl/ Propyl/ Butyl/ Pentyl/ higher/ 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 87 61.8 10.3 5.4 4.6 4.9 12.0 40.1 1.8 101 PER-11 94 60.5 10.8 5.7 4.7 4.9 13.3 37.8 2.0 85 PER-12 102 56.8 12.7 6.1 5.2 5.1 13.9 34.8 1.9 66

(16) Rubber Performance Test Methods:

(17) 1. 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 250 mm/min and a test temperature of 23±2° C. in accordance with the national standard GB/T 528-2009.

(18) 2. Mooney viscosity test: The test is carried out in accordance with the national standard GB/T 1232.1-2000, with a Mooney viscosity meter at a test temperature of 125° C. by preheating for 1 min, and the test is continued for 4 min.

(19) 3. Hot air accelerated aging test: The test is carried out at 135° C. for 168 h in accordance with the national standard GB/T 3512-2001, in a heat aging test chamber.

(20) 4. Volumetric resistivity test: The test is carried out using a megger in accordance with the national standard GB/T 1692-2008.

(21) 5. Oxygen index: The test is carried out in accordance with the national standard GB/T 2046.2-2009.

(22) Ultraviolet light with a dominant wavelength of 200-400 nm and a light intensity of 400-4000 mW/cm.sup.2 is used to carry out irradiation crosslinking at 160° C., and the lamp distance is controlled at 4-10 cm.

Example 1

(23) Branched polyethylene No. PER-7 was used.

(24) The processing and crosslinking steps were as follows:

(25) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° 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 2 min. Then 1 part of benzoin dimethyl ether was added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(26) (2) The specimen was crosslinked under ultraviolet light radiation for 10 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 2

(27) Branched polyethylene No. PER-7 was used.

(28) The processing and crosslinking steps were as follows:

(29) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° 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 2 min. Then 1 part of benzoin dimethyl ether was added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(30) (2) The specimen was crosslinked under ultraviolet light radiation for 10 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 3

(31) Branched polyethylene No. PER-7 was used.

(32) The processing and crosslinking steps were as follows:

(33) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene was added, prepressed and mixed for 2 min. Then 1 part of benzoin dimethyl ether was added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(34) (2) The specimen was crosslinked under ultraviolet light radiation for 10 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Comparative Example 1

(35) The processing and crosslinking steps were as follows:

(36) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of EPDM was added, prepressed and mixed for 2 min. Then 1 part of benzoin dimethyl ether was added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(37) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 4

(38) Branched polyethylene No. PER-6 was used.

(39) The processing and crosslinking steps were as follows:

(40) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° 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 2 min. Then 3 parts of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(41) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 5

(42) Branched polyethylene No. PER-6 was used.

(43) The processing and crosslinking steps were as follows:

(44) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene was added, prepressed and mixed for 2 min. Then 3 parts of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(45) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 6

(46) Branched polyethylene No. PER-9 was used.

(47) The processing and crosslinking steps were as follows:

(48) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 30 parts of EPM, 60 parts of EPDM and 10 parts of branched polyethylene were added, prepressed and mixed for 2 min. Then 3 parts of paraffin oil SUNPAR2280, 0.1 part of the antioxidant 1010, 2.5 parts of triarylsulfonium hexafluorophosphate, 1 part of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(49) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Example 7

(50) Branched polyethylene No. PER-8 was used.

(51) The processing and crosslinking steps were as follows:

(52) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 10 parts of EPM, 60 parts of EPDM, 30 parts of branched polyethylene and 0.1 part of the antioxidant 1010 were added, prepressed and mixed for 2 min. Then 5 parts of paraffin oil SUNPAR2280, 2.5 parts of triarylsulfonium hexafluorophosphate, 1 part of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(53) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

Comparative Example 2

(54) Branched polyethylene No. PER-8 was used.

(55) The processing and crosslinking steps were as follows:

(56) (1) Rubber mixing and molding: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of EPDM was added, prepressed and mixed for 2 min. Then 3 parts of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged. After being plasticated on an open mill, the rubber mix was pressed into a 1 mm thick specimen on a press vulcanizer.

(57) (2) The specimen was crosslinked under ultraviolet light radiation for 8 seconds, then allowed to stand for 16 h, and cut to be subjected to various tests.

(58) The performance test data of Examples 1-7 and Comparative Examples 1 and 2 are shown in the table below.

(59) TABLE-US-00002 Comparative Comparative Test Item Example 1 Example 2 Example 3 Example 1 Example 4 Example 5 Example 6 Example 7 Example 2 Tensile strength/ 8.6 10.3 11.2 7.4 11.3 13.2 10.5 11.2 9.2 MPa Elongation at break/ 858 793 778 946 763 732 612 769 867 % Volumetric resistiv- 2.8 × 10{circumflex over ( )}16 3.0 × 10{circumflex over ( )}16 3.1 × 10{circumflex over ( )}16 2.6 × 10{circumflex over ( )}16 2.8 × 10{circumflex over ( )}16 2.8 × 10{circumflex over ( )}16 2.7 × 10{circumflex over ( )}16 2.8 × 10{circumflex over ( )}16 2.7 × 10{circumflex over ( )}16 ity/Ω .Math. cm After aging at 135° C. for 168 h Retention rate of 104 102 104 105 103 102 103 102 105 tensile strength/% Retention rate of 95 93 96 94 93 95 97 96 93 elongation at break/ %

Example 8

(60) Branched polyethylene No. PER-5 was used.

(61) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 50 parts of EPDM, 50 parts of branched polyethylene, 0.8 part of the silane coupling agent KH570, 0.2 part of the antioxidant 1010 and 0.1 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 60 parts of calcined clay, 40 parts of talcum powder and 5 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 3.5 parts of ferrocene tetrafluoroborate, 1 part of benzoin dimethyl ether and 2 parts of triallyl isocyanurate (TAIC) were added, and the rubber compound was mixed for 3 min and then discharged.

(62) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Example 9

(63) Branched polyethylene No. PER-5 was used.

(64) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 30 parts of EPDM, 70 parts of branched polyethylene, 0.8 part of the silane coupling agent KH570 and 0.2 part of the antioxidant 1010 were added, prepressed and mixed for 2 min. Then 60 parts of calcined clay, 40 parts of talcum powder and 5 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 3 parts of benzoin dimethyl ether and 2 parts of triallyl isocyanurate (TAIC) were added, and the rubber compound was mixed for 3 min and then discharged.

(65) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Example 10

(66) Branched polyethylene No. PER-5 was used.

(67) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of branched polyethylene was added and prepressed, and 0.8 part of the silane coupling agent KH570, 0.2 part of the antioxidant 1010 and 0.1 part of the antioxidant DLTP were added and mixed for 2 min. Then 60 parts of calcined clay, 40 parts of talcum powder and 5 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 3.5 parts of ferrocene tetrafluoroborate, 1 part of benzophenone and 2 parts of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(68) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Comparative Example 3

(69) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of EPDM, 0.8 part of the silane coupling agent KH570 and 0.2 part of the antioxidant 1010 were added, prepressed and mixed for 2 min. Then 60 parts of calcined clay, 40 parts of talcum powder and 5 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 3 parts of benzoin dimethyl ether and 2 parts of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(70) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Example 11

(71) Branched polyethylene Nos. PER-2 and PER-5 were used.

(72) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 70 parts of PER-5, 30 parts of PER-2, 1 part of the silane coupling agent A-172 and 0.2 part of the antioxidant 1010 were added, prepressed and mixed for 2 min. Then 80 parts of calcined clay and 5 parts of paraffin oil SUNPAR2280 were added and the rubber compound was mixed for 3 min. Then 0.5 part of benzophenone and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(73) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 15 seconds.

Example 12

(74) Branched polyethylene No. PER-3 was used.

(75) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 50 parts of EPDM, 50 parts of branched polyethylene, 3 parts of zinc oxide, 0.3 part of the silane coupling agent A-172 and 0.3 part of the antioxidant 1010 were added, prepressed and mixed for 2 min. Then 10 parts of high-dispersibility silica, 40 parts of calcined clay and 5 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 5 parts of ferrocene hexafluorophosphate, 5 parts of benzophenone and 3 parts of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(76) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Example 13

(77) Branched polyethylene No. PER-4 was used.

(78) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 50 parts of EPDM, 50 parts of branched polyethylene, 0.3 part of the antioxidant 1010 and 0.2 part of DLTP were added, prepressed and mixed for 2 min. Then 150 parts of the silane coupling agent modified aluminum hydroxide and 10 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 3 parts of ferrocene hexafluorophosphate, 2 parts of benzophenone and 0.5 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(79) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

Example 14

(80) Branched polyethylene Nos. PER-1 and PER-7 were used.

(81) (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 PER-7, 20 parts of PER-1, 0.3 part of the antioxidant 1010 and 0.2 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 180 parts of the silane coupling agent modified aluminum hydroxide, 20 parts of calcined clay and 10 parts of paraffin oil SUNPAR2280 were added, and the rubber compound was mixed for 3 min. Then 4.5 parts of ferrocene hexafluorophosphate, 3.5 parts of benzoin dimethyl ether and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(82) (2) Extrusion and crosslinking: The rubber mix was extruded into a cable material by a double screw extruder. Then the cable material was subjected to melt extrusion to form the insulating layer or the sheathing layer coating a cable conductive core. The insulating layer or the sheathing layer was crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 10 seconds.

(83) The performance test data of the ultraviolet light crosslinked cable materials prepared in Examples 8-14 and Comparative Example 3 were as follows:

(84) TABLE-US-00003 Comparative Test Item Example 8 Example 9 Example 10 Example 3 Example 11 Example 12 Example 13 Example 14 Tensile strength/MPa 12.9 15.2 14.8 11.9 13.6 15.3 10.2 14.8 Elongation at break/% 456 553 516 587 673 428 419 343 Volumetric resistivity/ 2.5 × 10{circumflex over ( )}12 5.8 × 10{circumflex over ( )}14 6.9 × 10{circumflex over ( )}12 2.7 × 10{circumflex over ( )}14 7.2 × 10{circumflex over ( )}14 5.7 × 10{circumflex over ( )}14 8.6 × 10{circumflex over ( )}14 6.2 × 10{circumflex over ( )}14 Ω .Math. cm After aging (at 135° C. for 168 h) Retention rate of 106 105 106 108 105 105 106 107 tensile strength/% Retention rate of 94 96 95 94 96 96 93 94 elongation at break/% Oxygen index 31 32

(85) Examples of the present invention also include application of the above rubber composition for producing rubber products including wires and cables, films, gloves, condoms, and medical catheters.

(86) The specific examples thereof are described below.

Example 15

(87) A medical catheter was processed by the following steps:

(88) Branched polyethylene Nos. PER-8 and PER-2 were used.

(89) (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 PER-8, 20 parts of PER-2, 0.3 part of the antioxidant 1010 and 0.2 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 60 parts of talcum powder and 3 parts of paraffin oil SUNPAR2280 were added and the rubber compound was mixed for 3 min. Then 2 parts of ferrocene hexafluorophosphate, 2 parts of benzophenone and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(90) (2) Extrusion and vulcanization: The rubber mix was extruded into a rubber hose by a double screw extruder, and the rubber hose was immediately crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 15 seconds to obtain the medical catheter. The catheter material has a tensile strength of 18.5 MPa and an elongation at break of 680%, and meets the requirements of general medical catheters for various performances.

Example 16

(91) A medical catheter was processed by the following steps:

(92) Branched polyethylene No. PER-7 was used.

(93) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of PER-7, 0.3 part of the antioxidant 1010 and 0.2 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 40 parts of talcum powder and 3 parts of paraffin oil SUNPAR2280 were added and the rubber compound was mixed for 3 min. 0.1 part of benzophenone and 0.1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(94) (2) Extrusion and vulcanization: The rubber mix was extruded into a rubber hose by a double screw extruder, and the rubber hose was immediately crosslinked in a molten-state on-line continuous form under ultraviolet light radiation in an ultraviolet light radiation crosslinking device. The irradiation time was 15 seconds to obtain the medical catheter. The catheter material has a tensile strength of 10.5 MPa and an elongation at break of 880%, and meets the requirements of general medical catheters for various performances.

Example 17

(95) A condom was processed by the following steps:

(96) Branched polyethylene Nos. PER-7 and PER-2 were used.

(97) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 70 parts of PER-7, 30 parts of PER-4 and 0.2 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 2 parts of benzophenone and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(98) (2) Latex preparation: The rubber mix was dissolved in normal octane, and emulsification and dispersion were carried out to obtain latex.

(99) (3) Dip molding: A specific mold was dipped and dried in the latex several times, and ultraviolet light radiation for 30 seconds, crimping, demolding, finishing, electrical inspection, and packaging were carried out to finally obtain the condom. The condom has a thickness of 41 μm, a burst volume of 29 dm.sup.3, a burst pressure of 1.3 kPa, a tensile strength of 18.9 mpa, and an elongation at break of 768%, and meets the requirements of the international condom standard (55 EN ISO 4074: 2002 Natural latex rubber condoms: Requirements and test methods) for various performances.

Example 18

(100) Gloves were processed by the following steps:

(101) Branched polyethylene No. PER-7 was used.

(102) (1) Rubber mixing: The temperature of the internal mixer was set to 100° C., and the rotor speed was set to 50 rpm. 100 parts of PER-7, 0.8 part of the silane coupling agent A-172, 0.3 part of the antioxidant 1010 and 0.2 part of the antioxidant DLTP were added, prepressed and mixed for 2 min. Then 20 parts of talcum powder was added and the rubber compound was mixed for 3 min. Then 2 parts of ferrocene hexafluorophosphate, 2 parts of benzophenone and 1 part of trimethylolpropane triacrylate (TMPTA) were added, and the rubber compound was mixed for 3 min and then discharged.

(103) (2) Latex preparation: The rubber mix was dissolved in normal octane, and emulsification and dispersion were carried out to obtain latex.

(104) (3) Dip molding: A mold was cleaned and dried, dipped in a coagulating agent, dried, dipped in the latex, and lifted up. Ultraviolet light radiation crosslinking for 30 seconds, standing, edge coating, crimping, demolding, and finishing were carried out to obtain the gloves. The gloves have a breaking tenacity of 8.3 N, an elongation of 780%, and an adhesion rate of 0, and meet the requirements of the national standard (GB 10213-2006 Single-use medical rubber examination glove) for various performances.

Example 19

(105) A medical catheter uses branched polyethylene PER-12 as the rubber matrix, and the remaining formulation components and processing steps are same as Example 16.

(106) The catheter material has a tensile strength of 13.4 MPa and an elongation at break of 810%, and meets the requirements of general medical catheters for various performances.

Example 20

(107) A condom uses branched polyethylene PER-12 as the rubber matrix, and the remaining formulation components and processing steps are same as Example 17.

(108) The obtained condom has a thickness of 32 μm, a burst volume of 31 dm.sup.3, a burst pressure of 1.4 kPa, a tensile strength of 22.9 MPa, and an elongation at break of 733%, and meets the requirements of the international condom standard (55 EN ISO 4074: 2002 Natural latex rubber condoms: Requirements and test methods) for various performances.

Example 21

(109) Gloves use branched polyethylene PER-11 as the rubber matrix, and the remaining formulation components and processing steps are same as Example 18.

(110) The obtained gloves have a breaking tenacity of 11.8 N, an elongation of 660%, and an adhesion rate of 0, and meet the requirements of the national standard (GB 10213-2006 Single-use medical rubber examination glove) for various performances.