WO2018130189A1 - Rubber composite, processing, conveyor belt applying composite, and manufacturing method - Google Patents

Abstract

Disclosed is a rubber composite comprising the following in terms of parts by weight: a rubber substrate 100 parts, where the content of branched polyethylene is a : 0 < a ≤ 100 parts, and the total content of ethylene propylene monomer rubber and ethylene propylene diene monomer rubber is b : 0 ≤ b < 100 parts; a crosslinking agent 1.5-9 parts; a crosslink assisting agent: 0.2-9 parts; a reinforcing filler : 40-170 parts; a plasticizer : 6-93 parts; and a metal oxide 3-25 parts. The technical effect of the present invention is the provision of the rubber composite having heat resistance and great mechanical performance and applicable as a conveyor belt-covering rubber.

Description

Rubber composition and processing method, and conveyor belt and production method thereof Technical field

The invention belongs to the technical field of rubber, and particularly relates to a rubber composition, a processing method thereof, a conveyor belt using the rubber composition, and a method for producing a conveyor belt.

Background technique

Conveyor belts used in high temperature environments, in order to meet the high temperature performance requirements, some or all of the rubber parts of the conveyor belt (especially the cover layer in direct contact with the material) will be partially or fully heat resistant. Propylene rubber. However, the tensile strength of ethylene-propylene rubber is significantly lower than that of the substituted styrene-butadiene rubber or natural rubber, especially when a large amount of ethylene-propylene rubber is used in order to satisfy better heat resistance. The defects are more obvious. Therefore, the use of ethylene propylene rubber as a cover tape for heat-resistant conveyor belts limits the range of applications of such heat-resistant conveyor belts.

China Patent Licensing Bulletin No. CN101028888B discloses a high temperature resistant conveyor belt, which adopts the technology mainly by adding a binary ethylene propylene rubber or a diethylene propylene rubber and an EPDM rubber to an internal mixer for pre-pressure mixing, and adding a thermal conductive agent. The anti-aging agent is further mixed; then the reinforcing agent, the softener and the aramid short fiber are added to the rubber compound for mixing, and processed into a mixture of rubber; the above-mentioned rubber compound is added to the internal mixer to continue the second mixing. Refining, adding the cross-linking agent and the co-crosslinking agent in the second-stage mixing, and then dispersing the rubber evenly after the mixing; then the above-mentioned final rubber compound is hot-rolled into a film; the film and the anti-sliding canvas strip are attached. Synthetic type, rolled up for vulcanization, trimming inspection for finished products. However, the drawback of this rubber is that there is no mention of an improvement in the mechanical properties of the heat-resistant conveyor belt, and the introduction of short fibers significantly increases the processing difficulty and increases the production cost.

China Patent Licensing Publication No. CN102898730B also discloses a rubber material for a high temperature resistant conveyor belt and a manufacturing method thereof, which include EPDM rubber, carbon black, nano zinc oxide, stearic acid, dicumyl peroxide, and the like. Crosslinking agent, crosslinker, accelerator CZ, accelerator MDB, anti-aging agent MB, anti-aging agent 264, anti-aging agent RD, anti-aging agent 4020, polybutene, tackifying resin PN-110, tackifier reactive methyl Acrylate, magnesia, dispersant, special paraffinic hydrocarbon oil; this conveyor belt is based on the original addition of a co-crosslinking agent, cross-linking agent, accelerator MDB and special paraffinic hydrocarbon oil, so that the production The conveyor belt has better high temperature resistance. The defects of this kind of rubber still only emphasize the high temperature resistance, and can not significantly improve the mechanical strength of the heat-resistant conveyor belt.

Chinese Patent Publication No. CN104312018B discloses a heat-resistant conveyor belt cover rubber comprising a binary ethylene propylene rubber, a low Mooney EPDM rubber, a high wear resistant carbon black, a zinc methacrylate, a white carbon black, a paraffin wax, Adhesive enhancer, resorcinol, anti-aging agent and other components. The present invention solves the heat resistance of the conveyor belt, but it does not significantly improve the mechanical strength of the heat-resistant conveyor belt.

Ethylene-propylene rubber is a synthetic rubber with saturated molecular chain. It can be divided into two major categories: ethylene-propylene rubber and EPDM rubber. Both of them have good aging resistance. They are commonly used in ethylene-propylene rubber products. It is EPDM rubber, but because EPDM rubber contains a third monomer, the molecular chain contains double bonds, and the ethylene-propylene rubber molecular chain is completely saturated, so the ethylene-propylene rubber has more excellent resistance to aging. Sex, therefore, in the case of high requirements for aging resistance, it is a common technical solution to improve the aging resistance of EPDM by using ethylene propylene diene rubber together. However, the mechanical strength of the binary ethylene propylene rubber is low, which will affect the overall physical and mechanical properties.

Diethylene propylene rubber is a copolymer of ethylene and propylene and belongs to the copolymer of ethylene and α-olefin. Ethylene and α-olefin copolymers are polymers containing only hydrocarbon elements and saturated molecular chains. The common types of carbon atoms in such polymers are generally classified into primary, secondary and tertiary carbons, while tertiary carbons are the most It is easy to be trapped by hydrogen to form free radicals, so the ratio of tertiary carbon atoms to all carbon atoms is generally considered to be a major factor affecting the aging resistance of ethylene and α-olefin copolymers. The lower the ratio, the better the aging resistance. The ratio can be expressed by the degree of branching. For example, a diethylene propylene rubber having a propylene content of 60% by weight can be calculated to contain 200 propylene units per 1000 carbon atoms, that is, 200 tertiary carbon atoms or 200. One methyl branch, so its degree of branching is 200 branches / 1000 carbons. Ethylene ethylene propylene rubber generally has a weight percentage of 40% to 65% or 40% to 60%, so its branching degree is generally 117 to 200 branches/1000 carbons or 133 to 200 branches/ This degree of branching can be considered to be higher than other common ethylene and alpha-olefin copolymers in the 1000 carbon range.

In the prior art, the α-olefin in the common ethylene and α-olefin copolymer may be an α-olefin having a carbon number of not less than 4 in addition to propylene, and may be selected from a C ₄ - C ₂₀ α-olefin. It is usually selected from the group consisting of 1-butene, 1-hexene and 1-octene. If the degree of branching of the copolymer of ethylene and α-olefin is too low, the melting point and crystallinity are too high, and it is not suitable for use as a rubber component. If the degree of branching is high, the content of α-olefin is high, which may result in Process difficulty and raw material cost are high, and operability and economy are low. In the prior art, a polyolefin obtained by copolymerizing ethylene with 1-butene or ethylene and 1-octene may be referred to as a polyolefin plastomer or a polyolefin elastomer according to the degree of crystallinity and melting point, and a part of the polyolefin is elastic. Due to its proper crystallinity and melting point, it can be used well with ethylene propylene rubber and has a low degree of branching. It is considered to be an ideal material for improving the aging resistance of ethylene propylene rubber. It can replace ethylene propylene rubber to a certain extent. use. Since the molecular chain of ethylene and 1-octene copolymer is softer, more rubbery and has good physical and mechanical properties relative to the copolymer of ethylene and 1-butene, the polyolefin elastomer commonly used in rubber products is generally ethylene. And the copolymer of 1-octene, the octene weight percentage is generally not higher than 45%, more commonly not higher than 40%, the corresponding degree of branching is generally not higher than 56 branches / 1000 carbon, The more commonly used degree of branching is not higher than 50 branches/1000 carbons, which is much lower than the degree of branching of ethylene dipropylene rubber, so it has excellent aging resistance and good physical and mechanical properties.

The rubber generally needs to be used after cross-linking. In the cross-linking mode commonly used for ethylene-propylene rubber, the copolymer of ethylene and α-olefin may be peroxide cross-linking or irradiation cross-linking, both of which are mainly obtained by capturing tertiary carbon. a hydrogen atom forms a tertiary carbon radical, and then forms a carbon-carbon crosslink by radical bonding, but a copolymer of ethylene and 1-octene (hereinafter referred to as POE) has fewer tertiary carbon atoms and is attached to a tertiary carbon atom. The chain length is large, the steric hindrance is large, and the free radical reaction is difficult to occur, which leads to difficulty in crosslinking, affecting processing efficiency and product performance.

Therefore, there is a need for a better technical solution to improve the aging resistance of ethylene propylene rubber, while having good physical and mechanical properties and cross-linking performance, and it is expected to be specific functional indicators required for conveyor belt rubber products. (such as compression set, etc.) have a good performance.

Summary of the invention

In view of the problems in the prior art, the present invention provides a novel rubber composition formulation, and a method of processing the rubber composition, using a branching polymerization having a branching degree of not less than 50 branches/1000 carbons Ethylene replaces some or all of the ethylene propylene rubber and is vulcanized with peroxide. The present invention also provides a method of producing a high temperature resistant and high strength conveyor belt using the rubber composition, thereby changing the problem that the strength performance of the belt produced by the existing rubber is not good.

In order to achieve the above object, the present invention adopts the following technical solution: a rubber composition comprising a rubber matrix and essential components, comprising: a rubber matrix: 100 parts by weight; wherein the rubber matrix comprises the following components, Parts by weight: the content of branched polyethylene is a: 0 < a ≤ 100 parts; the content of binary ethylene propylene rubber b: 0 ≤ b < 100 parts; the content of ethylene propylene diene rubber c: 0 ≤ c < 100 parts , based on 100 parts by weight of the rubber matrix, the essential components include: cross-linking agent: 1.5 to 9 parts; co-crosslinking agent: 0.2 to 9 parts; reinforcing filler: 40 to 170 parts; plasticizer: 6 to 93 parts Metal oxide: 3 to 25 parts; wherein the branching degree of branched polyethylene is not less than 50 branches/1000 carbons, the weight average molecular weight is not less than 50,000, Mooney viscosity ML (1+4) 125 °C is not less than 2.

"Branched polyethylene" in the prior art means, in addition to a branched ethylene homopolymer, a branched saturated vinyl copolymer, such as an ethylene-α-olefin copolymer, which may be POE, although POE performs well in physical and mechanical properties and aging resistance, but cross-linking performance is not good, although the branched polyethylene of the present invention can contain both branched ethylene homopolymer and POE, but a better choice It is a branched polyethylene having a high proportion of branched polyethylene or a branched ethylene homopolymer. In a preferred embodiment of the invention, the branched polyethylene contains only branched ethylene homopolymer.

In the further elaboration of the technical solution of the present invention, the branched polyethylene used is a branched ethylene homopolymer unless otherwise specified.

The branched polyethylene used in the present invention is a kind of ethylene homopolymer having a branching degree of not less than 50 branches/1000 carbons, and can be called Branched Polyethylene or Branched PE. Currently, the synthesis method is mainly composed of a late transition metal catalyst. The homopolymerization of ethylene is catalyzed by a "chain walking mechanism", and the preferred late transition metal catalyst may be one of (α-diimine) nickel/palladium catalysts. The nature of the chain walking mechanism refers to the late transition metal catalyst. For example, the (α-diimine) nickel/palladium catalyst is more likely to undergo β-hydrogen elimination reaction and re-insertion reaction in the process of catalyzing olefin polymerization, thereby causing branching. Branched chains of such branched polyethylenes may have different numbers of carbon atoms, specifically 1 to 6, or more carbon atoms.

The production cost of the (α-diimine) nickel catalyst is significantly lower than that of the (α-diimine) palladium catalyst, and the (α-diimine) nickel catalyst catalyzes the high rate of ethylene polymerization and high activity, and is more suitable for industrial applications. Therefore, the branched polyethylene prepared by the ethylene polymerization of the (α-diimine) nickel catalyst is preferred in the present invention.

The degree of branching of the branched polyethylene used in the present invention is preferably 50 to 130 branches/1000 carbons, further preferably 60 to 130 branches/1000 carbons, further preferably 60 to 116 branches/1000. A carbon, the degree of branching between POE and ethylene-propylene rubber, is a new technical solution that is different from the prior art, and can have excellent aging resistance and good cross-linking performance.

Cross-linking performance includes factors such as crosslink density and cross-linking rate, which is the specific performance of the cross-linking ability of the rubber matrix during processing.

The branched polyethylene used in the present invention preferably has a methyl branch content of 40% or more or 50% or more, and has a certain similarity with the structure of the ethylene propylene diene rubber. In terms of cross-linking ability, the degree of branching (tertiary carbon atom content) and the steric hindrance around the tertiary carbon atom are the two main factors affecting the cross-linking ability of the saturated polyolefin. The branched polyethylene used in the present invention is low in degree of branching relative to the ethylene propylene rubber, and since the branched polyethylene has a branch having a carbon number of not less than 2, the branched polycondensation used in the present invention The steric hindrance around the tertiary carbon atom of ethylene is theoretically larger than that of ethylene propylene rubber. It can be judged by combining two factors that the crosslinking ability of the branched polyethylene used in the present invention should be weaker than that of the ethylene propylene rubber. In EPDM rubber. However, the actual cross-linking ability of the partially branched polyethylene used in the present invention is close to that of EPDM rubber, and may even be equal to or better than EPDM rubber. This means that the rubber composition of the present invention can obtain a good aging resistance, can also not weaken the crosslinking ability, and can even have excellent crosslinking performance to achieve an unexpected beneficial effect.

This may be explained by the fact that there may be an appropriate number of secondary branched structures on the branched polyethylene used in the preferred embodiment of the present invention, and the so-called secondary branched structure refers to a structure in which branches are further branched. This is also known as "branch-on-branch" during chain walking. Because of the low steric hindrance around the tertiary carbon atoms of the secondary branches, cross-linking reactions are more likely to occur. Having a secondary branched structure is a distinct distinction between the branched polyethylene used in the preferred embodiment of the present invention and the prior art ethylene dipropylene rubber or the conventional ethylene-α-olefin copolymer.

It is a new technical solution to improve the cross-linking ability of saturated polyolefin elastomer by using the secondary steric structure with lower steric hindrance. Under the technical solution of the present invention, it is also considered to be within the technical protection of the present invention to include a vinyl copolymer having a secondary branched structure or other saturated hydrocarbon polymer in the rubber matrix. The vinyl copolymer refers to a copolymer of ethylene and a branched α-olefin, and has a secondary branched structure, wherein the branched α-olefin may be selected from the group consisting of isobutylene and 3-methyl-1- Butylene, 4-methyl-1-pentene, 3-methyl-1-pentene, 2-methyl-1-heptene, 3-methyl-1-heptene, 4-methyl-1- The heptene, 5-methyl-1-heptene, 6-methyl-1-heptene, and the like, the comonomer may also contain a common linear alpha-olefin.

It is generally believed in the prior art that the branched polyethylene prepared by the (α-diimine) nickel catalyst is difficult to exist in the secondary branched structure, and at least it is difficult to sufficiently distinguish it. The technical solution of the present invention is also to analyze the branched polycondensation. The structure of ethylene provides a new idea.

Compared with ethylene propylene rubber, when the branched polyethylene has an appropriate number of secondary branched structures, the cross-linking point of the branched polyethylene can be generated on the tertiary chain of the main chain during the peroxide crosslinking process. It can also be produced on the branched tertiary carbon of the secondary structure, so the rubber network formed by the cross-linking of the branched polyethylene has a richer CC connecting segment between the main chains than the ethylene-propylene rubber. The length can effectively avoid stress concentration, and in the case of good cross-linking efficiency at the same time, the overall mechanical properties are expected to be obtained.

A further technical solution is that the content of the branched polyethylene in the rubber matrix is a: 10 ≤ a ≤ 100 parts, and the content of the binary ethylene propylene rubber b: 0 ≤ b ≤ 90 parts; The content of ethylene propylene diene monomer is c: 0 ≤ c ≤ 90 parts, and the branched polyethylene is an ethylene homopolymer having a branching degree of 60 to 130 branches/1000 carbons and a weight average molecular weight of 66,000. ~ 18,000, Mooney viscosity ML (1 + 4) 125 ° C is 6 ~ 102;

A further technical solution is that the content of the branched polyethylene in the rubber matrix is a: 10 ≤ a ≤ 100 parts, and the total content of the binary ethylene propylene rubber and the EPDM rubber is b: 0. ≤ b ≤ 90 parts; the branched polyethylene is an ethylene homopolymer having a degree of branching of 70 to 116 branches/1000 carbons, a weight average molecular weight of 201,000 to 436,000, and a Mooney viscosity ML (1) +4) 125 ° C is 23 ~ 101;

A further technical solution is that the content of the branched polyethylene in the rubber matrix is a: 10 ≤ a ≤ 100 parts, and the total content of the binary ethylene propylene rubber and the EPDM rubber is b: 0. ≤ b ≤ 90 parts; the branched polyethylene is an ethylene homopolymer having a degree of branching of 80 to 105 branches/1000 carbons, a weight average molecular weight of 250,000 to 400,000, and a Mooney viscosity ML (1) +4) 125 ° C is 40 to 95.

A further technical solution is that the content of the branched polyethylene in the rubber matrix is a: 10 ≤ a ≤ 100 parts, and the total content of the binary ethylene propylene rubber and the EPDM rubber is b: 0. ≤ b ≤ 90 parts; the branched polyethylene is an ethylene homopolymer having a degree of branching of 80 to 105 branches/1000 carbons, a weight average molecular weight of 268,000 to 356,000, and a Mooney viscosity ML (1) +4) 125 ° C is 42 to 80.

A further technical solution is that the third monomer of the ethylene propylene diene monomer is preferably a diene monomer, specifically selected from the group consisting of 5-ethylidene-2-norbornene and 5-vinyl-2-nor Borneene, dicyclopentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-pentadiene, 2-methyl-1,4-pentadiene, 3-methyl- 1,4-Hexadiene, 4-methyl-1,4-hexadiene, 1,9-decadiene, 5-methylene-2-norbornene, 5-pentylene-2-norbornate Alkene, 1,5-cyclooctadiene, 1,4-cyclooctadiene, and the like. Specifically, the ethylene propylene rubber may contain two or more kinds of diene monomers at the same time, such as 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene. The functional group of the diene monomer can play the same role as the intrinsic co-crosslinking agent in the peroxide vulcanization, thereby improving the crosslinking efficiency. This helps to reduce the amount of crosslinker and co-crosslinker required and the cost of adding them. The weight specific gravity of the diene monomer to the ethylene propylene rubber is preferably from 1% to 14%, more preferably from 3% to 10%, still more preferably from 4% to 7%.

According to a further aspect of the invention, the rubber composition further comprises an auxiliary component, wherein the auxiliary component comprises 1 to 3 parts by weight of the stabilizer, 1 to 5 parts by weight of the polyethylene glycol, and vulcanization accelerator 0 to 100 parts by weight of the rubber matrix. 3 parts by weight.

In a further technical solution, the stabilizer comprises 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl At least one of -1,2-dihydroquinoline (AW) and 2-mercaptobenzimidazole (MB).

In a further technical solution, the polyethylene glycol comprises at least one of polyethylene glycol having a molecular weight of 2000, 3400, and 4000.

According to a further technical proposal, the vulcanization accelerator comprises 2-thiol benzothiazole, dibenzothiazyl disulfide, tetramethyl thiuram monosulfide, tetramethyl thiuram disulfide, tetrazyl disulfide Kethiram, N-cyclohexyl-2-benzothiazolyl sulfenamide, N,N-dicyclohexyl-2-benzothiazolyl sulfenamide, bismaleimide, ethylene thiourea At least one of them.

In a further technical solution, the crosslinking agent comprises at least one of a peroxide crosslinking agent and a sulfur, and the peroxide crosslinking agent is 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-butyl) Base oxidized) hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, bis(tert-butylperoxyisopropyl)benzene, 2,5-di At least one of methyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxybenzoate, and t-butylperoxy-2-ethylhexyl carbonate.

A further technical solution is that the co-crosslinking agent comprises triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, Triallyl trimellitate, trimethylolpropane trimethacrylate, N,N'-m-phenylene bismaleimide, N,N'-bis-indenylacetone, 1,2- At least one of polybutadiene, a metal salt of an unsaturated carboxylic acid, and sulfur. The unsaturated carboxylic acid metal salt contains at least one of zinc acrylate, zinc methacrylate, magnesium methacrylate, calcium methacrylate, and aluminum methacrylate.

A further technical solution is that the plasticizer comprises stearic acid, pine tar, motor oil, naphthenic oil, paraffin oil, coumarone, RX-80, paraffin, liquid polyisobutylene, dioctyl sebacate. At least one. The rational use of plasticizers can increase the flexibility of the compound and the plasticity suitable for process operation. In order to increase the viscosity, it is also preferred to use an adhesion promoter such as pine tar, coumarone, RX-80, liquid polyisobutylene or the like.

In a further technical solution, the metal oxide comprises at least one of zinc oxide and magnesium oxide.

In a further technical solution, the reinforcing filler comprises at least one of carbon black, calcium carbonate, calcined clay, magnesium silicate, aluminum silicate, and magnesium carbonate.

In an embodiment of the present invention, in order to improve the adhesive property of the rubber compound, the rubber composition may further comprise a tackifier, and the pine tar, the coumarone resin, the RX-80, and the liquid polyisobutylene in the plasticizer have both The role of a tackifier, wherein the liquid coumarone resin has a better viscosity-increasing effect than the solid coumarone resin, and the tackifier may also be selected from the group consisting of C5 petroleum resin, C9 petroleum resin, hydrogenated rosin, terpene resin, and alkane. A commonly used tackifier such as a phenolic resin, a modified alkyl phenol resin, or an alkyl phenol-acetylene resin, and the tackifier is generally used in an amount of not more than 30 parts by weight, more preferably not more than 10 parts by weight based on 100 parts by weight of the rubber base. It is further preferably not more than 5 parts by weight.

The crosslinking agent, the co-crosslinking agent and the vulcanization accelerator involved in the rubber composition provided by the present invention all belong to a crosslinking system.

The rubber composition of the present invention may be present in the form of an uncrosslinked rubber compound, and may be present in the form of a vulcanized rubber after further crosslinking reaction. Vulcanized rubber can also be referred to simply as vulcanizate.

The present invention also provides a method of processing the above rubber composition, comprising the steps of:

(1) Rubber kneading: First, the rubber composition other than the cross-linking system is sequentially added to the internal mixer according to the parts by weight for kneading, and then added to the cross-linking system, uniformly kneaded, and discharged to obtain a rubber compound. The rubber compound is thinned on the open mill and then placed under the sheet to be vulcanized. Wherein, the crosslinking system comprises a crosslinking agent and a co-crosslinking agent, and may further comprise a vulcanization accelerator;

(2) Vulcanization: The rubber compound is filled into the cavity of the mold, and after being vulcanized by vulcanization on a flat vulcanizer, the vulcanized rubber is obtained by demolding.

The invention also provides a conveyor belt comprising a working surface covering glue and a non-working surface covering glue, wherein the working surface covering glue and the non-working surface covering glue are provided with a tensile layer, wherein the working surface is covered with glue and At least one layer of the non-working surface cover rubber comprises the above rubber composition.

The present invention also provides a method of producing a conveyor belt, the work surface covering tape of the conveyor belt comprising the rubber composition provided by the present invention, the production method comprising the steps of:

(1) Rubber kneading process: First, the rubber composition components other than the crosslinking system are sequentially added to an internal mixer according to parts by weight, and kneaded to obtain a master batch; the master batch is parked and then added to the mixture. The machine continues to mix, and the cross-linking system is uniformly mixed and discharged, and the final rubber is obtained for use. The cross-linking system comprises a crosslinking agent and a co-crosslinking agent, and may further comprise a vulcanization accelerator;

(2) calendering process: the above mixing rubber is placed in a screw extruder for hot refining, and then supplied to a calender for calendering and heat preservation for use;

(3) Molding process: the film is closely attached to the preformed adhesive tape strip blank on the forming machine to form a strip of the high temperature resistant conveyor belt, and then rolled up to be vulcanized;

(4) placing the formed conveyor belt blank into a flat vulcanizing machine for segmental vulcanization;

(5) After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

The invention also provides a cold-resistant conveyor belt, comprising a working surface covering glue and a non-working surface covering glue, wherein the working surface covering rubber and the non-working surface covering glue are provided with a tensile layer, the working surface is covered with glue and non-working At least one layer of the surface covering rubber comprises the above rubber composition, and the plasticizer of the rubber composition used contains a cold-resistant plasticizer, and the cold-resistant plasticizer may be selected from dioctyl sebacate, preferably in an amount of 10 to 30. Parts by weight.

The invention also provides a conductive conductive conveyor belt, comprising a working surface covering glue and a non-working surface covering glue, wherein the working surface covering glue and the non-working surface covering glue are provided with a tensile layer, and the working surface is covered with glue and non-working At least one layer of the working surface covering rubber comprises the above rubber composition, and the reinforcing filler in the rubber composition used contains at least one of conductive carbon black and graphite powder, and the conductive carbon black may be selected from conductive furnace black At least one of (CF), superconducting furnace carbon black (SCF), special conductive furnace carbon black (XCF), and acetylene black (ACEF). The total amount of the conductive carbon black and/or the graphite powder is preferably 15 to 40 parts by weight.

The present invention also provides a tubular conveyor belt comprising an inner cover rubber and an outer cover rubber, a tensile layer is disposed between the inner cover rubber and the outer cover rubber, and at least one of the inner cover rubber and the outer cover rubber comprises The above rubber composition.

Compared with the prior art, the beneficial effects of the invention are: because the molecular structure of the branched polyethylene is completely saturated, the heat aging resistance is similar to that of the ethylene propylene rubber, and is superior to the EPDM rubber, and can be used. The oxide system is vulcanized. The production process of the conveyor belt requires the use of medium and low Mooney viscosity rubber grades, while the branched polyethylene has more long-chain branches than ethylene-propylene rubber or EPDM rubber, and has more molecular weights. The small hydrodynamic volume, that is, the Mooney viscosity, is low, so that the branched polyethylene can be used with higher molecular weight and higher mechanical strength, while also meeting the requirements of medium and low Mooney viscosity. On the other hand, since the branched polyethylene has more branches in its molecular structure, and the length of the branch has a certain length and length distribution and a certain number of secondary branched structures exist, during the peroxide crosslinking process, the branch The cross-linking point of the polyethylene can be produced on the tertiary carbon of the main chain or on the branched tertiary carbon of the secondary structure, so the rubber network formed by the cross-linking of the branched polyethylene and the ethylene-propylene rubber Compared with the main chain, there is a richer CC link segment length, similar to the polysulfide bond in the sulfur vulcanization system, but the bond energy is higher, which can effectively avoid stress concentration, and at the same time have good cross-linking efficiency. Under the whole, it is expected to obtain better mechanical properties. Therefore, when the rubber matrix contains branched polyethylene, the rubber composition is used for the covering layer of the conveyor belt, which can effectively improve the shortcomings of the prior art, and to some extent solve the current transportation of ethylene-propylene rubber as the main rubber component. The problem of low mechanical strength of the cover layer.

detailed description

The following examples are given to further illustrate the present invention, but are not intended to limit the scope of the present invention, and some non-essential improvements and adjustments made by those skilled in the art based on the present invention remain within the scope of the present invention. .

In order to more clearly describe the embodiments of the present invention, the materials to which the present invention relates are defined below.

The crosslinking system comprises a crosslinking agent and a co-crosslinking agent, and may further comprise a vulcanization accelerator.

In the present invention, the ethylene-diene rubber selected from the rubber base has a Mooney viscosity ML (1+4) of preferably 30 to 55 at 125 ° C and an ethylene content of preferably 45% to 60%. The ethylene propylene rubber used has a Mooney viscosity ML (1+4) of preferably 30 to 100 at 125 ° C, an ethylene content of preferably 55% to 75%, and a third monomer of 5-ethylidene-2-norbornene, 5 - Vinyl-2-norbornene or dicyclopentadiene, the third monomer content being from 1% to 7%.

The branched polyethylene used can be obtained by catalyzing the homopolymerization of ethylene by a (α-diimine) nickel catalyst under the action of a cocatalyst. The structure, synthesis method and method for preparing branched polyethylene by using the (α-diimine) nickel catalyst are disclosed in the prior art, and can be used but are not limited to the following documents: CN102827312A, CN101812145A, CN101531725A, CN104926962A, US6103658, US6660677.

The selected branched polyethylene is characterized by a branching degree of 60 to 130 branches/1000 carbons, a weight average molecular weight of 66,000 to 518,000, and a Mooney viscosity of ML (1+4) of 125 ° C of 6 to 102. . Among them, the degree of branching is measured by nuclear magnetic resonance spectroscopy, and the molar percentages of various branches are measured by nuclear magnetic carbon spectroscopy.

The details are as follows:

Rubber performance test method:

1. Hardness test: According to the national standard GB/T 531.1-2008, the test is carried out with a hardness tester, and the test temperature is room temperature;

2, tensile strength, elongation at break performance test: in accordance with the national standard GB/T528-2009, using an electronic tensile testing machine for testing, the tensile speed is 500mm / min, the test temperature is 23 ± 2 ° C, the sample is type 2 Dumbbell sample

3, Mooney viscosity test: in accordance with the national standard GB/T1232.1-2000, with Mooney viscosity meter for testing, the test temperature is 125 ° C, preheat 1 minute, test 4 minutes;

4, hot air accelerated aging test: in accordance with the national standard GB/T3512-2001, in the heat aging test chamber, the test conditions are 150 ° C × 72h;

5, DIN wear test: according to the national standard GB/T9867-1998, using a roller wear machine, the preparation of cylindrical vulcanizate sample, sample diameter, 16 ± 0.2mm, height of 8mm, test temperature 23 ± 2 ° C;

6. Positive curing time Tc90 test: According to the national standard GB/T16584-1996, it is carried out in a rotorless vulcanizer, and the test temperature is 160 °C.

The vulcanization conditions of the following Examples 1-9 and Comparative Examples 1 and 2 were uniform: temperature: 160 ° C; pressure: 16 MPa; time was Tc90 + 2 min.

The present invention will be further described below in conjunction with specific embodiments:

A rubber composition comprising: a rubber substrate: 100 parts by weight; wherein the rubber matrix comprises the following components, all in parts by weight: the content of the branched polyethylene is a: 0 < a ≤ 100 parts; The content of the binary ethylene propylene rubber b: 0 ≤ b < 100 parts; the content of the ethylene propylene diene rubber c: 0 ≤ c < 100 parts, based on 100 parts by weight of the rubber matrix, further comprising: a crosslinking agent: 1.5 to 9 Co-crosslinking agent: 0.2-9 parts; reinforcing filler: 40-170 parts; plasticizer: 6-93 parts; metal oxide: 3-25 parts; wherein the branching degree of branched polyethylene is not Below 50 branches/1000 carbons, the weight average molecular weight is not less than 50,000, and the Mooney viscosity ML (1+4) is not lower than 2 at 125 °C.

A preferred embodiment: the content of the branched polyethylene in 100 parts by weight of the rubber matrix is a: 10 ≤ a ≤ 100 parts; the content of the binary ethylene propylene rubber b: 0 ≤ b ≤ 90 parts; the content of the EPDM rubber c: 0 ≤ c ≤ 90 parts, a further preferred embodiment: 100 parts by weight of the rubber matrix are branched polyethylene.

Wherein, the above-mentioned preferred branched polyethylene has a degree of branching of 60-130 branches/1000 carbons, a weight average molecular weight of 66,000 to 518,000, and a Mooney viscosity of ML (1+4) of 125 ° C of 6 to 102. .

The rubber composition further includes 1 to 3 parts by weight of a stabilizer, 1 to 5 parts by weight of polyethylene glycol, and 0 to 3 parts by weight of a vulcanization accelerator, based on 100 parts by weight of the rubber base.

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

The vulcanization accelerator comprises 2-thiol benzothiazole, dibenzothiazole disulfide, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, N-ring At least one of hexyl-2-benzothiazolylsulfenamide, N,N-dicyclohexyl-2-phenylthiazolylsulfenamide, bismaleimide, and ethylenethiourea.

The crosslinking agent comprises at least one of a peroxide crosslinking agent and sulfur, and the peroxide crosslinking agent comprises 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-di(benzene At least one of formyl peroxide, hexane, tert-butyl peroxybenzoate, and t-butylperoxy-2-ethylhexyl carbonate.

The co-crosslinking agent comprises triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, triallyl trimellitate , trimethylolpropane trimethacrylate, N,N'-m-phenylene bismaleimide, N,N'-bis-indenylene acetonone, 1,2-polybutadiene, zinc acrylate, At least one of zinc methacrylate, magnesium methacrylate, calcium methacrylate, aluminum methacrylate, and sulfur.

The plasticizer comprises at least one of stearic acid, pine tar, motor oil, naphthenic oil, paraffin oil, coumarone, RX-80, paraffin wax, liquid polyisobutylene, and the metal oxide comprises at least zinc oxide and magnesium oxide. One.

The reinforcing filler contains at least one of carbon black, calcium carbonate, calcined clay, magnesium silicate, aluminum silicate, and magnesium carbonate.

A method of processing the above rubber composition, wherein the processing method comprises the following steps:

(1) Rubber mixing: set the temperature of the internal mixer to 70-120 ° C, the rotor speed is 30-50 rpm, add the rubber matrix pre-pressing and kneading for 90 seconds; add zinc oxide, stearic acid and antioxidant RD, Mix for 1 minute;

(2) then adding carbon black and paraffin oil to the above rubber compound, and kneading for 3 minutes;

(3) Finally, 3 parts of cross-linking agent and co-crosslinking agent are added, and the rubber is discharged after 2 minutes of mixing;

(4) The kneaded rubber is thinly passed on an open mill having a roll temperature of 50 to 70 ° C to obtain a sheet and parked for 20 hours;

(5) After the vulcanization, the test was carried out for 16 hours.

The above vulcanization conditions are: temperature: 160 ° C; pressure: 16 MPa; time is Tc90 + 2 min.

The utility model relates to a conveyor belt, which comprises a working surface covering glue and a non-working surface covering glue, a tensile layer is arranged between the working surface covering rubber and the non-working surface covering glue, and the working surface covering rubber and the non-working surface covering rubber are all the rubber mentioned above. The composition is made.

A method of producing the above conveyor belt according to the claims, the production method comprising the steps of:

(1) Rubber mixing process: set the temperature of the internal mixer to 70 ° C, the rotor rotation speed is 50 rpm, add 100 parts of branched polyethylene pre-pressure mixing for 60 seconds; add 10 parts of zinc oxide, 1 part of stearic acid Mix with 1 part of antioxidant RD for 1 minute; then add 50 parts of carbon black N330, 20 parts of paraffin oil SUNPAR2280 to the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent dicumyl peroxide (DCP) ), 1 part of the cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, after 2 minutes of mixing;

(2) Calendering process: the above mixing rubber is placed in a screw extruder for hot refining, and then calendered in a calender to be used for filming. When the film is rolled out, the film thickness is controlled at 4.5 to 12 mm. use;

(3) Molding process: the film is closely attached to the preformed adhesive tape strip blank on the forming machine to form a strip of the high temperature resistant conveyor belt, and then vulcanized after being rolled up for 4 hours;

(4) The above-mentioned shaped conveyor belt blank is placed in a flat vulcanizing machine for segmental vulcanization, each plate has a vulcanization time of 25 minutes, a vulcanization pressure of 3 MPa, and a vulcanization temperature of 160 ° C;

(5) After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

In order to test the performance of the rubber, the present invention will be described below in conjunction with specific embodiments:

Example 1:

The branched polyethylene used was numbered PER-9.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 100 ° C, the rotor speed to 50 rpm, add 90 parts of EPDM rubber and 10 parts of branched polyethylene for 90 seconds premixing; add 5 parts of oxidation Zinc, 0.2 parts of stearic acid, 1 part of antioxidant RD, kneaded for 1 minute; then add 60 parts of carbon black N330, 25 parts of paraffin oil SUNPAR2280 to the compound, knead for 3 minutes; finally add 5 parts of cross-linking agent Dicumyl oxide (DCP), 1 part of the cross-linking agent, triallyl isocyanurate (TAIC), after 2 minutes of mixing, the rubber was discharged, and the mixture was placed on an open mill with a roll temperature of 60 ° C. Thin, get a sheet thickness of about 2.5mm, park for 20 hours

(2) After the vulcanization, the test was carried out for 16 hours.

Example 2:

The branched polyethylene used was numbered PER-8.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 80 parts of ethylene propylene diene rubber and 20 parts of branched polyethylene for 90 seconds; add 10 parts of oxidation Zinc and 2 parts of stearic acid were mixed for 1 minute; then 80 parts of carbon black N330, 25 parts of paraffin oil SUNPAR 2280 were added to the compound, and kneaded for 3 minutes; finally, 1 part of cross-linking agent dicumyl peroxide was added. DCP), 0.5 parts of cross-linking agent sulfur, 1.5 parts of vulcanization accelerator tetramethylthiuram disulfide and 1 part vulcanization accelerator tetramethyl thiuram vulcanized, glued for 2 minutes, then glued, rubber compound The sheet was thinly passed on an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 3:

The branched polyethylene used was numbered PER-5.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 100 ° C, the rotor speed is 50 rpm, add 20 parts of ethylene propylene rubber, 50 parts of ethylene propylene diene monomer and 30 parts of branched polyethylene pre-pressure mixing. 90 seconds; add 15 parts of zinc oxide, 3 parts of magnesium oxide, 3 parts of stearic acid, 1 part of antioxidant RD, and knead for 1 minute; then add 50 parts of carbon black N330, 10 parts of paraffin oil SUNPAR 2280 to the rubber compound. Mixing for 3 minutes; finally adding 6 parts of cross-linking agent dicumyl peroxide (DCP), 2 parts of cross-linking agent triallyl isocyanurate (TAIC), mixing for 2 minutes, then discharging the glue, The rubber compound was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 4:

The branched polyethylene used was numbered PER-4.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed is 50 rpm, add 50 parts of ethylene propylene diene monomer and 50 parts of branched polyethylene for 90 seconds; add 10 parts of oxidation 1 part of zinc stearic acid, 1 part of antioxidant RD, kneaded for 1 minute; then add 50 parts of carbon black N330, 20 parts of paraffin oil SUNPAR2280 to the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent peroxidation Dicumyl (DCP), 1 part of the cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, after 2 minutes of mixing, the rubber is discharged, and the rubber is mixed at the roll temperature. It was thin on the 60 ° C open mill, and a sheet having a thickness of about 2.5 mm was obtained and parked for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 5:

The branched polyethylene used was numbered PER-3.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 80 ° C, the rotor speed is 50 rpm, add 20 parts of ethylene propylene diene rubber and 80 parts of branched polyethylene for pre-pressure mixing for 90 seconds; add 7 parts of oxidation Zinc, 1.5 parts of stearic acid, 2 parts of polyethylene glycol PEG4000 and 1 part of antioxidant RD, kneaded for 1 minute; then 100 parts of carbon black N330, 20 parts of calcium carbonate and 60 parts of paraffin oil SUNPAR 2280 were added to the compound. The mixture was kneaded for 3 minutes; finally, 6 parts of a cross-linking agent, dicumyl peroxide (DCP), and 1 part of a cross-linking agent, triallyl isocyanurate (TAIC), were added, and the mixture was kneaded for 2 minutes and then discharged. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 6

The branched polyethylene used was numbered PER-4.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene pre-pressed and kneaded for 90 seconds; add 10 parts of zinc oxide, 1 part of stearic acid and 1 part of antioxidant RD, mixing for 1 minute; then add 50 parts of carbon black N330, 20 parts of paraffin oil SUNPAR2280 to the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent dicumyl peroxide (DCP) 1 part of the cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, after 2 minutes of mixing, the rubber is discharged, and the mixture is placed on an open mill with a roll temperature of 60 ° C. Thin, get a sheet thickness of about 2.5mm, park for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 7

The branched polyethylene used was numbered PER-5.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 50 parts of ethylene propylene diene rubber and 50 parts of branched polyethylene pre-pressed for 90 seconds; add 10 parts of oxidation Zinc, 3 parts of magnesium oxide, 2 parts of stearic acid and 1 part of antioxidant RD, kneaded for 1 minute; then add 50 parts of carbon black N330 and 20 parts of paraffin oil SUNPAR 2280 to the compound, knead for 3 minutes; finally add 3 A cross-linking agent, dicumyl peroxide (DCP), 1 part of a cross-linking agent, triallyl isocyanurate (TAIC), and 0.3 parts of a cross-linking agent, sulfur, were mixed for 2 minutes and then discharged. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 8

The branched polyethylenes used were numbered PER-1 and PER-6.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 80 parts of PER-6 and 20 parts of PER-1 pre-pressed for 90 seconds; add 3 parts of zinc oxide and 1 Part of the antioxidant RD, mixing for 1 minute; then add 40 parts of carbon black N330 and 6 parts of paraffin oil SUNPAR2280 in the compound, mixing for 3 minutes; finally adding 2 parts of cross-linking agent dicumyl peroxide (DCP) and 0.2 parts of the crosslinking agent sulfur, and the rubber was discharged after 2 minutes of mixing. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Example 9

The branched polyethylenes used were numbered PER-2 and PER-7.

The processing steps for testing the rubber composition are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 70 parts of PER-7 and 30 parts of PER-2 pre-pressed for 90 seconds; add 20 parts of zinc oxide, 5 Part of magnesium oxide, 3 parts of stearic acid and 2 parts of antioxidant RD, mixing for 1 minute; then adding 120 parts of carbon black N330, 50 parts of calcium carbonate and 90 parts of paraffin oil SUNPAR 2280 to the compound, mixing for 3 minutes; Add 9 parts of cross-linking agent dicumyl peroxide (DCP), 2 parts of cross-linking agent triallyl isocyanurate (TAIC) and 7 parts of cross-linking agent 1,2-polybutadiene, Dispense after 2 minutes of mixing. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Comparative Example 1:

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed is 50 rpm, add 100 parts of EPDM rubber for 90 seconds, and add 10 parts of zinc oxide and 1 part of stearic acid. And 1 part of antioxidant RD, mixing for 1 minute; then add 50 parts of carbon black N330 and 20 parts of paraffin oil SUNPAR2280 in the compound, mixing for 3 minutes; finally adding 3 parts of cross-linking agent dicumyl peroxide (DCP) 1 part of the co-crosslinking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, which was mixed for 2 minutes and then discharged. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

Comparative Example 2:

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 50 parts of ethylene propylene diene rubber and 50 parts of EPDM rubber for 90 seconds; add 10 parts Zinc oxide, 3 parts of magnesium oxide, 2 parts of stearic acid and 1 part of antioxidant RD, kneaded for 1 minute; then 50 parts of carbon black N330 and 20 parts of paraffin oil SUNPAR 2280 were added to the compound, and kneaded for 3 minutes; 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of co-crosslinking agent were mixed by sulfur for 2 minutes and then degreased. The kneaded rubber was thinly passed through an open mill having a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and was left to stand for 20 hours.

(2) After the vulcanization, the test was carried out for 16 hours.

The test performance comparison is shown in the following table:

Performance data analysis:

By comparison of Example 4, Example 6 and Comparative Example 1, it can be found that as the content of branched polyethylene in the rubber composition increases, the tensile strength increases remarkably, the elongation at break increases, and the wear resistance is better. There is no significant change in thermal stability. The same trend of change can also be found by comparison of Example 7 with Comparative Example 2. Therefore, the branched polyethylene is used as the rubber component of the conveyor cover rubber, which is beneficial to improve the mechanical strength and wear resistance of the cover rubber, so that the heat-resistant conveyor belt can be applied to more occasions.

Example 10:

The high temperature resistant conveyor belt is provided with a cored tensile canvas between the working surface covering rubber and the non-working surface covering glue, which makes them a solid whole through molding and vulcanization process.

The working surface of the high temperature resistant conveyor belt covers the composition and proportion of the rubber in terms of the number of parts. The production method includes the following steps:

(1) Rubber mixing process:

Set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-3 pre-pressure mixing for 60 seconds; add 10 parts of zinc oxide, 1 part of stearic acid and 1 part of antioxidant RD, knead for 1 minute; then add 50 parts of carbon black N330, 20 parts of paraffin oil SUNPAR 2280 to the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of help The cross-linking agent, triallyl isocyanurate (TAIC), and 0.3 parts of the cross-linking agent, sulfur, were mixed for 2 minutes and then discharged.

(2) Calendering process:

The above rubber mixture is placed in a screw extruder for hot refining, and then supplied to a calender for calendering to be used. The thickness of the film is controlled to be 4.5 to 12 mm when the film is rolled. After being good, keep warm for use.

(3) Molding process:

The film is closely attached to the pre-formed adhesive canvas strip on the molding machine to form a strip of the high temperature resistant conveyor belt, and then vulcanized after being rolled up for 4 hours.

(4) Vulcanization process:

The formed conveyor belt blank was placed in a flat vulcanizing machine for stage vulcanization, and the vulcanization time per plate was 25 minutes, the vulcanization pressure was 3 MPa, and the vulcanization temperature was 160 °C.

(5) Trimming and inspection:

After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

Example 11

A cold-resistant conveyor belt, the production process is as follows:

(1) Rubber mixing process:

Set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-3 pre-pressure mixing for 60 seconds; add 5 parts of zinc oxide, 1 part of stearic acid and 1 part of antioxidant RD, knead for 1 minute; then add 60 parts of carbon black N330, 5 parts of paraffin oil SUNPAR 2280 and 15 parts of dioctyl sebacate in the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent Propylene (DCP), 1 part of the cross-linking agent, triallyl isocyanurate (TAIC), and 0.3 parts of the cross-linking agent sulfur, were mixed for 2 minutes and then discharged.

(2) Calendering process:

The above rubber mixture is placed in a screw extruder for hot refining, and then supplied to a calender for calendering to be used. The thickness of the film is controlled to be 4.5 to 12 mm when the film is rolled. After being good, keep warm for use.

(3) Molding process:

The film is used as a cover glue on the molding machine and closely attached to the pre-formed adhesive canvas strip to form a strip of the cold-resistant conveyor belt, and then vulcanized after being rolled up for 4 hours.

(4) Vulcanization process:

The formed conveyor belt blank was placed in a flat vulcanizing machine for stage vulcanization, and the vulcanization time per plate was 25 minutes, the vulcanization pressure was 2.5 MPa, and the vulcanization temperature was 160 °C.

(5) Trimming and inspection:

After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

Example 12

An electrostatic conductive conveyor belt, the production process is as follows:

(1) Rubber mixing process:

Set the temperature of the internal mixer to 70 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-3 pre-pressure mixing for 60 seconds; add 5 parts of zinc oxide, 1 part of stearic acid and 1 part of antioxidant RD, kneading for 1 minute; then adding 40 parts of carbon black N330, 20 parts of acetylene black and 20 parts of paraffin oil SUNPAR 2280 to the compound, mixing for 3 minutes; finally adding 3 parts of cross-linking agent dicumyl peroxide ( DCP), 1 part of the cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, which were mixed for 2 minutes and then discharged.

(2) Calendering process:

The above rubber mixture is placed in a screw extruder for hot refining, and then supplied to a calender for calendering to be used. The thickness of the film is controlled to be 4.5 to 12 mm when the film is rolled. After being good, keep warm for use.

(3) Molding process:

The film is closely attached to the preform as a cover rubber on the molding machine and formed into a strip of the conductive conductive belt, and then vulcanized after being rolled up for 4 hours.

(4) Vulcanization process:

The formed conveyor belt blank was placed in a flat vulcanizing machine for stage vulcanization, and the vulcanization time per plate was 25 minutes, the vulcanization pressure was 2.5 MPa, and the vulcanization temperature was 160 °C.

(5) Trimming and inspection:

After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

Example 13

A high-strength high-temperature conveyor belt, the production process is as follows:

(1) Rubber mixing process:

Set the temperature of the internal mixer to 100 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-10 pre-pressure mixing for 60 seconds; add 5 parts of zinc oxide, 1 part of stearic acid, 3 parts of Gu Ma Long resin and 1 part of antioxidant RD, knead for 1 minute; then add 60 parts of carbon black N330, 20 parts of paraffin oil SUNPAR2280 in the compound, mix for 3 minutes; finally add 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of the cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of the cross-linking agent sulfur, which were mixed for 2 minutes and then discharged.

(2) Calendering process:

The above rubber mixture is placed in a screw extruder for hot refining, and then supplied to a calender for calendering to be used. The thickness of the film is controlled to be 4.5 to 12 mm when the film is rolled. After being good, keep warm for use.

(3) Molding process:

The film is used as a cover glue on the molding machine and closely attached to the pre-formed adhesive canvas strip to form a strip of the high-temperature resistant conveyor belt, and then vulcanized after being rolled up for 4 hours.

(4) Vulcanization process:

The formed conveyor belt blank was placed in a flat vulcanizing machine for stage vulcanization, and the vulcanization time per plate was 25 minutes, the vulcanization pressure was 2.5 MPa, and the vulcanization temperature was 160 °C.

(5) Trimming and inspection:

After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

In this embodiment, the tensile strength of the conveyor belt cover rubber reaches 27.3 MPa.

Example 14

A high-strength high-temperature resistant conveyor belt, the cover rubber and the adhesive core glue adopt the rubber composition provided by the invention, and the production process is as follows:

(1) Rubber mixing process:

Covering rubber mixing: set the temperature of the mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of branched polyethylene PER-12 pre-pressure mixing for 60 seconds; add 8 parts of zinc oxide, 1 part of stearic acid 3 parts of coumarone resin and 1 part of antioxidant RD, mixing for 1 minute; then adding 60 parts of carbon black N330, 10 parts of paraffin oil SUNPAR2280 to the compound, mixing for 3 minutes; finally adding 3 parts of cross-linking agent Dicumyl oxide (DCP), 1 part of the co-crosslinking agent, triallyl isocyanurate (TAIC), and 0.3 parts of the cross-linking agent, sulfur, were mixed for 2 minutes and then discharged.

Adhesive core rubber mixing:

Set the temperature of the internal mixer to 95 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-11 pre-pressure mixing for 60 seconds; add 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of liquid ancient Malone resin, 2 parts of pine tar, 2 parts of modified alkyl phenolic resin TKM-M and 1 part of antioxidant RD, kneaded for 1 minute; then add 60 parts of carbon black N330, 10 parts of paraffin oil SUNPAR 2280 and 5 parts of liquid polyisobutylene, mixing for 3 minutes; finally adding 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of cross-linking agent triallyl isocyanurate (TAIC) and 0.3 parts of help The cross-linking agent is sulfur, and the rubber is discharged after 2 minutes of mixing.

(2) Calendering process:

The above rubber mixture is placed in a screw extruder for hot refining, and then supplied to a calender for calendering to be used. The thickness of the film is controlled to be 4.5 to 12 mm when the film is rolled. After being good, keep warm for use.

(3) Molding process:

The film is formed as a cover rubber on a molding machine and closely formed with a pre-formed canvas strip containing an adhesive core to form a strip of a high-temperature resistant conveyor belt, and then vulcanized after being rolled up for 4 hours.

(4) Vulcanization process:

The formed conveyor belt blank was placed in a flat vulcanizing machine for stage vulcanization, and the vulcanization time per plate was 25 minutes, the vulcanization pressure was 2.5 MPa, and the vulcanization temperature was 160 °C.

(5) Trimming and inspection:

After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse.

In this embodiment, the tensile strength of the conveyor belt cover rubber reaches 29.5 MPa.

The conveyor belts of Examples 13 and 14 have a tensile strength close to that of natural rubber and have aging resistance equal to or better than that of ethylene propylene rubber, and are a high temperature resistant and high strength conveyor belt.

The superiority of the branched polyethylene in cross-linking ability is demonstrated by the cross-linking performance test comparison of Examples 15, 16 and Comparative Example 3.

The rubber substrate used in Example 23 was 100 parts of PER-12, and the rubber substrate used in Example 24 was 50 parts of PER-12 and 50 parts of ethylene propylene diene monomer (ML (1+4) 125 ° C was 60, and the ethylene content was 68. %, ENB content 4.8%), the rubber substrate used in Comparative Example 3 was 100 parts of the ethylene propylene diene rubber used in Example 16. The rest of the formula is consistent.

The processing steps of the three rubber compositions are as follows:

(1) kneading: setting the temperature of the internal mixer to 80 ° C, the rotation speed of the rotor to 50 rpm, adding a rubber matrix pre-pressing and kneading for 90 seconds; adding 10 parts of zinc oxide, 1 part of stearic acid, and kneading for 1 minute;

(2) then adding 70 parts of carbon black N550, 15 parts of calcium carbonate, 45 parts of paraffin oil to the rubber compound, and kneading for 3 minutes;

(3) Finally, 3 parts of cross-linking agent BIPB and 1 part of cross-linking agent TAIC were added, and after 2 minutes of mixing, the glue was discharged;

(4) The rubber compound was thinly passed on an open mill with a roll temperature of 60 ° C to obtain a sheet having a thickness of about 2.5 mm, and the vulcanization property was tested after standing for 20 hours;

The test conditions were 175 ° C, 30 min, and the test results were as follows:

Example 15 Example 16 Comparative Example 3 ML, dN.m 1.24 1.03 0.55 MH, dN.m 11.81 11.24 11.03 MH-ML, dN.m 10.57 10.21 10.48 Tc90,min 6.5 7.3 8.0

The rubber composition of Example 15 had the shortest Tc90 and the highest MH-ML value, indicating that the branched polyethylene used in this example can be superior in cross-linking ability to the conventional EPDM rubber in cross-linking ability.

The application of the rubber composition of the invention in the field of conveyor belt can greatly expand the application range of the existing high temperature resistant conveyor belt and optimize the industrial structure of the conveyor belt.

Claims (18)

A rubber composition comprising, in terms of unit parts by weight, a rubber matrix and an essential component, wherein the rubber matrix is 100 parts, and the rubber matrix comprises the following components, all in parts by weight: The content of polyethylene is a: 0 < a ≤ 100 parts; the content of binary ethylene propylene rubber b: 0 ≤ b < 100 parts; the content of ethylene propylene diene rubber c: 0 ≤ c < 100 parts, with 100 weight For the rubber base, the essential components include: a crosslinking agent: 1.5 to 9 parts; a crosslinking agent: 0.2 to 9 parts; a reinforcing filler: 40 to 170 parts; a plasticizer: 6 to 93 parts; Oxide: 3 to 25 parts, wherein the branched polyethylene comprises an ethylene homopolymer having a branching degree of not less than 50 branches/1000 carbons, a weight average molecular weight of not less than 50,000, and a Mooney viscosity ML ( 1+4) 125 ° C is not less than 2. The rubber composition according to claim 1, wherein the rubber base comprises a branched polyethylene: 100 parts by weight; and the essential component comprises: cross-linking based on 100 parts by weight of the rubber base Agent: 1.5 to 9 parts; co-crosslinking agent: 0.2 to 9 parts; reinforcing filler: 40 to 170 parts; plasticizer: 6 to 93 parts; metal oxide: 3 to 25 parts; It is an ethylene homopolymer having a degree of branching of not less than 50 branches/1000 carbons, a weight average molecular weight of not less than 50,000, and a Mooney viscosity of ML (1+4) of not less than 2 at 125 °C. The rubber composition according to claim 1, wherein the content of the branched polyethylene in the 100 parts by weight of the rubber matrix is a: 10 ≤ a ≤ 100 parts; the content of the binary ethylene propylene rubber b: 0 ≤ B≤90 parts; the content of ethylene propylene diene rubber c: 0 ≤ c ≤ 90 parts, the branched polyethylene is an ethylene homopolymer, the degree of branching is 60 to 130 branches / 1000 carbon, heavy The average molecular weight is 66,000 ~ 518,000, Mooney viscosity ML (1 + 4) 125 ° C is 6 ~ 102; The rubber composition according to claim 1, wherein the rubber composition further comprises an auxiliary component in an amount of 100 parts by weight per unit of the rubber base, the auxiliary component comprising 1 to 3 parts of a stabilizer, and polyethylene glycol 1 to 5 parts, vulcanization accelerator 0 to 3 parts. The rubber composition according to claim 4, wherein the stabilizer comprises 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy group- At least one of 2,2,4-trimethyl-1,2-dihydroquinoline (AW) and 2-mercaptobenzimidazole (MB). The rubber composition according to claim 4, wherein the polyethylene glycol comprises at least one of polyethylene glycol having a molecular weight of 2,000, 3,400, and 4,000. The rubber composition according to claim 4, wherein the vulcanization accelerator comprises 2-thiol benzothiazole, dibenzothiazole disulfide, tetramethylthiuram monosulfide, and tetrasulfide disulfide. Kethiram, tetraethylthiuram disulfide, N-cyclohexyl-2-benzothiazolyl sulfenamide, N,N-dicyclohexyl-2-phenylthiazolyl sulfenamide, bismaleyl At least one of an imine and an ethylene thiourea. The rubber composition according to claim 1, wherein the crosslinking agent comprises at least one of a peroxide crosslinking agent and sulfur, and the peroxide crosslinking agent is 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-butylperoxyperoxide) Of phenyl, 2,5-dimethyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxybenzoate, t-butylperoxy-2-ethylhexyl carbonate At least one. The rubber composition according to claim 1, wherein the co-crosslinking agent comprises triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, Triethylene glycol dimethacrylate, triallyl trimellitate, trimethylolpropane trimethacrylate, N,N'-m-phenylene bismaleimide, N,N'-double At least one of mercaptoacetone, 1,2-polybutadiene, a metal salt of an unsaturated carboxylic acid, and sulfur. The rubber composition according to claim 1, wherein the plasticizer comprises stearic acid, pine tar, motor oil, naphthenic oil, paraffin oil, coumarone, RX-80, paraffin, liquid polyisobutylene At least one of dioctyl sebacate. The rubber composition according to claim 1, wherein the metal oxide comprises at least one of zinc oxide and magnesium oxide. The rubber composition according to claim 1, wherein the reinforcing filler comprises at least one of carbon black, calcium carbonate, calcined clay, magnesium silicate, aluminum silicate, and magnesium carbonate. A method of processing the rubber composition according to any one of claims 1 to 12, characterized in that the processing method comprises the steps of: (1) Rubber kneading: First, the rubber composition other than the cross-linking system is sequentially added to the internal mixer for mixing by weight, and then added to the cross-linking system, uniformly kneaded, and discharged to obtain a rubber compound. The rubber compound is thinned on the open mill, and then left, and parked, waiting for vulcanization. The cross-linking system comprises a crosslinking agent and a co-crosslinking agent, and may further comprise a vulcanization accelerator; (2) Vulcanization: The rubber compound is filled into the cavity of the mold, and after being vulcanized by vulcanization on a flat vulcanizer, the vulcanized rubber is obtained by demolding. A conveyor belt comprising a working surface covering glue and a non-working surface covering glue, wherein the working surface covering glue and the non-working surface covering glue are provided with a tensile layer, wherein the working surface is covered with glue and non-working At least one layer of the face covering rubber comprises the rubber composition according to any one of claims 1 to 12. A method of producing a conveyor belt according to claim 15, wherein the production method comprises the following steps: (1) Rubber kneading process: First, the rubber composition components other than the crosslinking system are sequentially added to an internal mixer according to parts by weight, and kneaded to obtain a master batch; the master batch is parked and then added to the mixture. The machine continues to mix, and the cross-linking system is uniformly mixed and discharged, and the final rubber is obtained for use. The cross-linking system comprises a crosslinking agent and a co-crosslinking agent, and may further comprise a vulcanization accelerator; (2) calendering process: the above mixing rubber is placed in a screw extruder for hot refining, and then supplied to a calender for calendering and heat preservation for use; (3) Molding process: the film is closely attached to the pre-formed adhesive canvas strip blank on the forming machine to form a strip of high temperature resistant conveyor belt, and then rolled up for waiting for vulcanization; (4) placing the formed conveyor belt blank into a flat vulcanizing machine for segmental vulcanization; (5) After the vulcanization is finished, it is trimmed, inspected, and then packaged into the warehouse. A cold-resistant conveyor belt comprising a working surface covering rubber and a non-working surface covering glue, wherein the working surface covering rubber and the non-working surface covering rubber are provided with a tensile layer, wherein the working surface covering rubber comprises a right The rubber composition according to any one of 1 to 12, wherein the plasticizer of the rubber composition used contains a cold-resistant plasticizer. An electrostatically conductive conveyor belt comprising an inner cover rubber and an outer cover rubber, and a tensile layer is disposed between the inner cover rubber and the outer cover rubber, wherein at least one of the inner cover rubber and the outer cover rubber is The layer comprises the rubber composition according to any one of claims 1 to 12, and the reinforcing filler in the rubber composition used contains at least one of conductive carbon black and graphite powder. A tubular conveyor belt comprising an inner cover rubber and an outer cover rubber, and a tensile layer is disposed between the inner cover rubber and the outer cover rubber, characterized in that at least one of the inner cover rubber and the outer cover rubber A rubber composition according to any one of claims 1 to 12.