WO2018130199A1

WO2018130199A1 - Rubber composite, processing method, rubber tube applying composite, and manufacturing method

Info

Publication number: WO2018130199A1
Application number: PCT/CN2018/072374
Authority: WO
Inventors: 徐涛; 傅智盛; 吴安洋
Original assignee: 杭州星庐科技有限公司
Priority date: 2017-01-13
Filing date: 2018-01-12
Publication date: 2018-07-19

Abstract

Provided are a rubber composite, a method for processing the rubber composite, a rubber tube comprising the rubber composite, and a manufacturing method. The rubber composite comprises in terms of unit parts by weight: a rubber substrate 100 parts, a crosslinking agent 1.5-8 parts, a reinforcing filler 50-200 parts, and a plasticizer 10-100 parts, and also comprises a crosslink assisting agent 0.2-8 parts, a metal oxide 2-15 parts, a stabilizer 1-3 parts, and polyethylene glycol 1-5 parts, where the rubber substrate, calculated at 100 parts by weight, comprises: branched polyethylene, the content thereof being a: 0 < a ≤ 100 parts, ethylene propylene monomer rubber and ethylene propylene diene monomer rubber, the content thereof being b: 0 ≤ b < 100 parts.

Description

Rubber composition and processing method, and hose and production method thereof

Technical field

The present invention relates to the field of rubber technology, and in particular to a rubber composition and a processing method for obtaining the rubber composition, and to a hose for applying the rubber composition, and a method for producing the product.

Background technique

Ethylene-propylene rubber has a wide range of applications in the field of hoses. As some hose applications (such as automotive radiator hoses and brake hoses) have higher requirements for heat resistance and compression set resistance, the hose vulcanization process has been adopted from the original. Sulfur vulcanization, gradually tended to use peroxide vulcanization, in order to obtain better heat resistance and compression set resistance. However, the tear strength of the rubber after peroxide vulcanization is lower than sulfur vulcanization, which causes the hose to cause more waste in the production process, reduce production efficiency and increase production cost.

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. Chain length, large steric hindrance, difficulty in radical reaction, resulting in difficulty in crosslinking, affecting processing efficiency and product performance, such as compression set resistance is unsatisfactory.

Therefore, a better technical solution is needed to improve the aging resistance of ethylene propylene rubber, and at the same time, it has good physical and mechanical properties and cross-linking performance, and is expected to be specific to the functional indexes required for rubber-based rubber products ( Such as anti-compression permanent deformation, etc.) have a good performance.

Summary of the invention

In view of the problems existing in the prior art, the present invention provides a rubber composition, and its application and production method in a hose, using a branched polyethylene having a branching degree of not less than 50 branches/1000 carbons. Instead of some or all of the ethylene propylene rubber, peroxide vulcanization, the new rubber composition can be used as a rubber inner layer and/or outer rubber layer compound, or as a pure rubber compound.

The rubber matrix of the rubber composition of the present invention may be composed entirely of branched polyethylene, or may be composed of branched polyethylene and ethylene propylene rubber, composed of branched polyethylene and ethylene propylene diene rubber, and branched polycondensation. Ethylene is composed of ethylene propylene diene rubber and ethylene propylene diene monomer. The combination of branched polyethylene and ethylene propylene diene rubber can improve the mechanical properties and processing properties of ethylene propylene diene rubber. The combination of branched polyethylene and EPDM rubber can improve the heat aging resistance of EPDM rubber. And mechanical properties, a small amount of diene in EPDM plays the same role as an intrinsic co-crosslinker in peroxide vulcanization.

In order to achieve the above object, the technical solution adopted by the present invention relates to a rubber composition comprising, by weight, a rubber matrix and an essential component, wherein the rubber matrix comprises: the content of the branched polyethylene is a: 0 <a ≤ 100 parts; the sum of the contents of the binary ethylene propylene rubber and the ethylene propylene diene rubber b: 0 ≤ b < 100 parts; and the necessary components include: 1.5 to 8 parts of the crosslinking agent, based on 100 parts by weight of the rubber substrate, 50 to 200 parts of the reinforcing filler and 10 to 100 parts of the plasticizer. The branching degree of the branched polyethylene is not less than 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.

"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 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 help to obtain better mechanical properties, including tear strength. Therefore, the technical solution of the present invention can provide a rubber compound and a hose which have both good heat resistance and tear strength.

A further technical solution is that, in 100 parts by weight, the content of branched polyethylene in the rubber matrix is a: 10 ≤ a ≤ 100 parts; the content of the binary ethylene propylene rubber and the ethylene propylene diene rubber is b: 0 ≤ b ≤ 90 The branched polyethylene is an ethylene homopolymer having a degree of branching 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). ) 125 ° C is 6 ~ 102.

A further preferred technical solution for the branched polyethylene is that the degree of branching is 70 to 116 branches/1000 carbons, the weight average molecular weight is 201,000 to 436,000, and the Mooney viscosity ML (1+4) is 125 ° C. ~101.

A further preferred technical solution for the branched polyethylene is that the degree of branching is from 80 to 105 branches/1000 carbons, the weight average molecular weight is from 250,000 to 400,000, and the Mooney viscosity ML (1+4) is 40 °C. ~95.

A further preferred technical solution for the branched polyethylene is that the degree of branching is 80 to 105 branches/1000 carbons, the weight average molecular weight is 268,000 to 356,000, and the Mooney viscosity ML (1+4) is 125 ° C. ~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 and residual 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%.

A further technical solution is that the crosslinking agent comprises at least one of a peroxide crosslinking agent and a sulfur, the peroxide crosslinking agent comprising di-tert-butyl peroxide, dicumyl peroxide, and tert-butyl Kecumyl peroxide, 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butyl Oxidation) hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl At least one of -2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxybenzoate, t-butylperoxy-2-ethylhexyl carbonate, more preferably, a crosslinking agent It is 2 to 6 parts by weight.

A further technical solution is that the reinforcing filler comprises at least one of carbon black, calcium carbonate, calcined clay, magnesium silicate, aluminum silicate, magnesium carbonate, talc, diatomaceous earth, preferably, in 100 parts by weight. The rubber base meter further contains 40 to 150 parts by weight of carbon black, and the carbon black is used as a rubber reinforcing agent to greatly improve the mechanical strength of the rubber compound. The talc powder herein may be more preferably a talc powder treated with a vinyl silane coupling agent.

A further technical solution is that the plasticizer comprises at least one of stearic acid, pine tar, motor oil, naphthenic oil, paraffin oil, coumarone, RX-80, paraffin, liquid polyisobutylene, and dioctyl sebacate. Among them, stearic acid can also act as an active agent in a system mainly based on sulfur vulcanization, and can form a soluble salt with some metal oxides, thereby increasing the activation effect of the metal oxide on the promoter. 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.

A further technical solution is that the rubber composition further comprises an auxiliary component, and the auxiliary component comprises: 0.2 to 8 parts of a co-crosslinking agent, 2 to 15 parts of a metal oxide, and 1 to 3 parts of a stabilizer, based on 100 parts by weight of the rubber matrix. 1 to 5 parts of polyethylene glycol and 0 to 3 parts of vulcanization accelerator.

A further technical solution is that the co-crosslinking agent comprises triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, ethyl dimethacrylate, dimethacrylate Triethylene diester, triallyl trimellitate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, N, N'-m-phenylene bismaleimide, N At least one of N'-bis-indenyl acetonone, 1,2-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.

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

A further technical solution is that the stabilizer comprises 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl-1 At least one of 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, zinc di-n-butyldithiocarbamate, N-cyclohexyl-2-benzothiazolyl sulfenamide, N,N-dicyclohexyl-2-benzothiazolyl sulfenamide, double horse At least one of imide and ethylene thiourea.

In an embodiment of the present invention, in order to improve the viscosity of the rubber compound, the rubber composition may further comprise a tackifier, wherein the plasticizer is pine tar, coumarone resin, RX-80, and liquid polyisobutylene. The role of the adhesive, 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, alkyl group. A commonly used tackifier such as a phenol resin, a modified alkyl phenol resin, or an alkyl phenol-acetylene resin, and the tackifier is generally not more than 30 parts by weight, further 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, and the vulcanized rubber may also be simply referred to as a vulcanizate.

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

(1) Rubber mixing: setting the temperature of the internal mixer and the rotation speed of the rotor, and adding the components other than the crosslinking system in the rubber composition to the internal mixer for mixing; then adding the crosslinking system, mixing and arranging Glue, the obtained rubber compound is thinly passed on the open mill, the lower sheet, the parking, the crosslinking system comprises a crosslinking agent, and may further comprise at least one of a co-crosslinking agent and a vulcanization accelerator;

(2) Vulcanization: the rubber compound is filled into the cavity of the mold, heated and pressurized by vulcanization on the flat vulcanizer, and then the mold is released to obtain the vulcanized rubber. In order to improve the mechanical strength and compression set resistance of the vulcanizate, further Vulcanization is carried out using a two-stage vulcanization process

The present invention also provides a pure rubber hose, the rubber compound comprising the above rubber composition.

A method for producing the above pure rubber hose, the production method comprising the following steps:

(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. After the rubber compound is thinned on the open mill, the film is to be vulcanized, the crosslinking system comprises a crosslinking agent, and at least one of a crosslinking agent and a vulcanization accelerator may be further included;

(2) Extrusion and molding: a cold feed extruder is used to extrude the rubber layer on the mandrel to obtain a tube blank, which is cooled by steam vulcanization, de-core, trimmed, inspected, and stored in a warehouse to obtain a hose.

The invention also provides an automobile radiator hose, wherein at least one of the inner rubber layer and the outer rubber layer comprises the above rubber composition.

The invention also provides a method for producing a car radiator hose, comprising the following steps:

(1) Rubber kneading: setting the appropriate temperature of the internal mixer and the rotor rotation speed, and adding the rubber composition other than the crosslinking system to the internal mixer in order of mixing, and then kneading, and then adding the crosslinking system to be kneaded. After uniformly discharging, the mixture is obtained, the mixture is thinned on the open mill, and then the sheet is to be vulcanized, the crosslinking system contains a crosslinking agent, and at least one of a crosslinking agent and a vulcanization accelerator may be further included. Species

(2) Extrusion and molding: using a cold feed extruder, extruding the inner rubber layer, then knitting the fiber reinforced layer on the inner rubber layer, and then extruding the outer rubber layer to obtain a tube blank, and cutting the vulcanization;

(3) Vulcanization: The mandrel is inserted into the tube blank, cooled by steam vulcanization, de-core, trimmed, inspected, and stored in the warehouse to obtain a car radiator hose.

The present invention also provides an air conditioning hose, wherein at least one of an inner rubber layer and an outer rubber layer comprises the above rubber composition.

The invention also provides a method for producing an air conditioning hose, comprising the following steps:

(1) Rubber kneading: setting the appropriate temperature of the internal mixer and the rotor rotation speed, and adding the rubber composition other than the crosslinking system to the internal mixer in order of mixing, and then kneading, and then adding the crosslinking system to be kneaded. After uniform discharge, the mixture is obtained, and the rubber mixture is thinned on the open mill and then placed under the sheet to be vulcanized. The crosslinking system comprises a crosslinking agent, and may further comprise at least one of a co-crosslinking agent and a vulcanization accelerator;

(2) Extrusion and molding: preparing a mandrel, extruding a nylon alloy lining on the mandrel, extruding the inner rubber layer, weaving the fiber reinforced layer, and then extruding the outer rubber layer;

(3) Vulcanization: vulcanization, disintegration, core removal and truncation. Get the air conditioning hose.

A further technical solution is that the rubber compound used in the outer rubber layer of the radiator hose or the air-conditioning hose may further comprise a binder to enhance the bonding property with the fiber reinforced layer. The component of the binder may be a polyisocyanate salt, and the amount thereof is preferably from 1 to 3 parts by weight. The present invention also provides a rubber hose assembly in which at least one of an inner rubber layer and an outer rubber layer comprises the above rubber composition.

The present invention also provides a method of producing a rubber hose assembly comprising the steps of:

(1) rubber mixing: the raw materials of the inner rubber layer and the outer rubber layer are respectively processed into an inner layer rubber mixture and an outer layer rubber mixture by an open mill or an internal mixer, and the impurities are filtered out after passing the test;

(2) Tube blank forming: the inner rubber layer is extruded by a cold feed extruder, and the aramid fiber layer is knitted on the outer surface of the inner rubber layer, and finally the outer rubber compound is extruded through an outer rubber layer extruder. And coating on the outer surface of the aramid fiber layer to form a tube blank;

(3) vulcanization: the above tube blank is placed on the tube core, placed in a steam vulcanization tank, steam is pressurized to 0.9 MPa, heated to 175 ° C, and vulcanized for 25 minutes to obtain a vulcanized rubber hose;

(4) Loading the clamp: After cleaning and cutting the above vulcanized rubber hose, the pre-opening clamp is bonded at both ends of each hose to obtain a rubber hose assembly.

Compared with the prior art, the present invention has the beneficial effects that the rubber composition containing the branched polyethylene has higher tensile strength and tearing properties under the same or similar conditions of other formulation ingredients. The production of a hose from such a rubber composition can significantly reduce the probability of tearing of the hose during production and use. At the same time, its resistance to 150 ° C hot air aging performance is maintained at the same level as the rubber composition of ethylene propylene rubber alone, or a slight advantage, can meet the high temperature use requirements of the current similar radiator hoses and air conditioning hoses.

detailed description

The rubber composition and a hose according to the present invention are further described below in conjunction with the embodiments. The following examples are merely illustrative of the technical solutions and are not intended to limit the invention. All parts which are not specifically described in the examples are parts by weight.

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 contains a crosslinking agent, and may further contain at least one of a co-crosslinking agent and a vulcanization accelerator.

In the present invention, the ethylene-propylene rubber selected from the rubber base has a Mooney viscosity ML (1+4) of preferably 20 to 50 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 20 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:

The specific performance method and the rubber performance test method involved in the relevant experiments:

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, tear performance test: in accordance with the national standard GB/T529-2008, using an electronic tensile test machine for testing, the tensile speed is 500mm / min, the test temperature is 23 ± 2 ° C, the sample is a rectangular sample;

4. Mooney viscosity test: According to the national standard GB/T1232.1-2000, the test is carried out with a Mooney viscometer. The test temperature is 125 ° C, preheating for 1 minute, testing for 4 minutes;

5, 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;

6, the positive curing time Tc90 test: in accordance with the national standard GB/T16584-1996, in the rotorless vulcanizer, the test temperature is 170 ° C;

The vulcanization conditions of the following Examples 1 to 12 and Comparative Examples 1 and 2 were as follows: temperature: 170 ° C; pressure: 16 MPa; time was Tc90 + 1 min.

Example 1:

The branched polyethylene used was numbered PER-7.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 100 ° C, the rotor speed is 50 rpm, add 90 parts of ethylene propylene diene rubber and 10 parts of branched polyethylene for 90 seconds; add 2 parts of PEG 4000 1 part of antioxidant RD, mixing for 30 seconds; then adding 80 parts of carbon black N550, 20 parts of paraffin oil SUNPAR2280 to 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), was mixed for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 2:

The branched polyethylene used was numbered PER-6.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed to 50 rpm, add 85 parts of EPDM rubber and 15 parts of branched polyethylene pre-pressed for 90 seconds; add 2 parts of PEG4000 1 part of antioxidant RD, mixing for 30 seconds; then adding 80 parts of carbon black N550, 30 parts of paraffin oil SUNPAR2280 to 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), after 2 minutes of mixing, the rubber is discharged, and the mixture is thinned on an open mill with a roll temperature of 60 ° C to obtain about 2.5 mm. Thick sheet, parked for 20 hours;

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

Example 3:

The branched polyethylene used was numbered PER-4.

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 70 parts of EPDM rubber and 30 parts of branched polyethylene pre-pressed for 90 seconds; add 2 parts of PEG4000 1 part of antioxidant RD, mixing for 30 seconds; then adding 80 parts of carbon black N550, 30 parts of paraffin oil SUNPAR2280 to 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), was mixed for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 4:

The branched polyethylene used was numbered PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° 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 2 parts of PEG 4000 1 part of antioxidant RD, mixing for 30 seconds; then adding 80 parts of carbon black N550, 30 parts of paraffin oil SUNPAR2280 to 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), after 2 minutes of mixing, the rubber is discharged, and the mixture is thinned on an open mill with a roll temperature of 60 ° C to obtain about 2.5 mm. Thick sheet, 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-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 20 parts of ethylene propylene diene rubber, 30 parts of ethylene propylene diene monomer and 50 parts of prepolymerized polyethylene. 90 seconds; add 2 parts of PEG4000, 1 part of antioxidant RD, mix for 30 seconds; then add 100 parts of carbon black N550, 30 parts of paraffin oil SUNPAR2280 in the compound, mix for 3 minutes; finally add 3 parts of crosslinker Dicumyl peroxide (DCP), 1 part of the cross-linking agent, triallyl isocyanurate (TAIC), after 2 minutes of mixing, the rubber is discharged, and the mixture is melted at a roll temperature of 60 ° C. Thin on the machine, 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 6

The branched polyethylene used was numbered PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed to 50 rpm, add 30 parts of EPDM rubber and 70 parts of branched polyethylene pre-pressed for 90 seconds; add 2 parts of PEG4000 2 parts of anti-aging agent RD, mixing for 30 seconds; then adding 170 parts of carbon black N550, 100 parts of paraffin oil SUNPAR2280 to the compound, mixing for 3 minutes; finally adding 8 parts of cross-linking agent dicumyl peroxide (DCP) 3 parts of the co-crosslinking agent, triallyl isocyanurate (TAIC), was mixed for 2 minutes and then discharged. The kneaded rubber 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 was left 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 are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of branched polyethylene pre-pressed and kneaded for 90 seconds; add 2 parts of PEG4000, 1 part of antioxidant RD, mix Refining for 30 seconds; then adding 80 parts of carbon black N550, 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 cross-linking agent The triallyl isocyanurate (TAIC) was degreased after 2 minutes of kneading, and 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: rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of EPDM rubber for 90 seconds, and add 2 parts of PEG 4000, 1 part. Anti-aging agent RD, mixing for 30 seconds; then adding 80 parts of carbon black N550 and 20 parts of paraffin oil SUNPAR2280 to the compound, mixing for 3 minutes; finally adding 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 The cross-linking agent, triallyl isocyanurate (TAIC), 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.

Example 8

The branched polyethylenes used were numbered PER-3 and PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 30 parts of PER-3 and 70 parts of PER-5 pre-pressure mixing for 90 seconds; add 5 parts of zinc oxide, 1 Part of stearic acid, 2 parts of PEG4000, 1 part of antioxidant RD, kneaded for 30 seconds; then add 100 parts of carbon black N550, 100 parts of calcium carbonate and 80 parts of paraffin oil SUNPAR2280 to the compound, knead for 3 minutes; 4 parts of cross-linking agent dicumyl peroxide (DCP), 2 parts of the cross-linking agent triallyl isocyanurate (TAIC), and the mixture was mixed for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 9

The branched polyethylene used was numbered PER-4.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 60 ° C, the rotor speed to 50 rpm, add 30 parts of ethylene propylene diene rubber and 70 parts of branched polyethylene pre-pressure mixing for 90 seconds; add 5 parts of oxidation Zinc, 1 part stearic acid, 2 parts PEG4000, 1 part antioxidant RD, kneaded for 30 seconds; then add 30 parts carbon black N550, 50 parts carbon black N774, 15 parts paraffin oil SUNPAR2280 in the rubber compound, mix 3 Minutes; finally, 3 parts of cross-linking agent dicumyl peroxide (DCP) and 1 part of cross-linking agent triallyl isocyanurate (TAIC) were added, and after 2 minutes of mixing, the gum was 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 10:

The branched polyethylene used was numbered PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed to 50 rpm, add 70 parts of EPDM rubber and 30 parts of branched polyethylene pre-pressed for 90 seconds; add 3 parts of oxidation Zinc, 2 parts PEG4000, 1 part antioxidant RD, kneaded for 30 seconds; then add 50 parts carbon black N550, 10 parts paraffin oil SUNPAR2280 in the rubber compound, mix for 3 minutes; finally add 1 part cross-linking agent peroxide Cumene (DCP), 0.3 parts of co-crosslinker triallyl isocyanurate (TAIC), 0.5 part of crosslinker sulfur, 1 part of N-cyclohexyl-2-benzothiazole sulfenamide ( CZ) and 0.8 parts of tetramethylthiuram disulfide (TMTD), which were mixed for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 11

The branched polyethylenes used were numbered PER-2 and PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 20 parts of PER-2 and 80 parts of PER-5 pre-pressure mixing for 90 seconds; add 10 parts of zinc oxide, 1 a portion of stearic acid, 2 parts of PEG4000, 1 part of antioxidant RD, kneaded for 30 seconds; then add 40 parts of carbon black N550, 60 parts of carbon black 774, 20 parts of paraffin oil SUNPAR 2280 to the compound, and knead for 3 minutes; 3 parts of cross-linking agent dicumyl peroxide (DCP), 8 parts of co-crosslinking agent 1,2-polybutadiene were added, and the mixture was kneaded for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 12

The branched polyethylenes used were numbered PER-1 and PER-5.

The processing steps are as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed to 50 rpm, add 10 parts of PER-1 and 90 parts of PER-5 pre-pressing for 90 seconds; add 5 parts of magnesium oxide, 1 Stearic acid, 2 parts PEG4000, 1 part antioxidant RD, kneaded for 30 seconds; then add 100 parts carbon black N550, 30 parts paraffin oil SUNPAR2280 in the rubber compound, mix for 3 minutes; finally add 5 parts crosslinker Dicumyl peroxide (DCP), 2 parts of the cross-linking agent, triallyl isocyanurate (TAIC), 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 60 ° C, the rotor speed to 50 rpm, add 100 parts of EPDM rubber for 90 seconds, and add 5 parts of zinc oxide and 1 part of stearic acid. 2 parts of PEG4000, 1 part of antioxidant RD, kneaded for 30 seconds; then add 30 parts of carbon black N550, 50 parts of carbon black N774, 30 parts of paraffin oil SUNPAR2280 in the compound, mix for 3 minutes; finally add 3 parts The mixture of dicumyl peroxide (DCP), 1 part of the cross-linking agent, triallyl isocyanurate (TAIC), was mixed for 2 minutes and then discharged. The kneaded rubber 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 was left for 20 hours;

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

Example 13

An automobile radiator hose, wherein the rubber composition used for the inner rubber layer is the rubber composition used in the seventh embodiment. The production process is as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of branched polyethylene pre-pressed and kneaded for 90 seconds; add 2 parts of PEG4000, 1 part of antioxidant RD, mix Refining for 30 seconds; then adding 80 parts of carbon black N550, 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 cross-linking agent Triallyl isocyanurate (TAIC), after 2 minutes of mixing, the gum was discharged. The mixture is thinned on the open mill and then placed on the sheet to be vulcanized.

(3) Vulcanization: The mandrel is inserted into the tube blank, vulcanized by high temperature steam, the temperature is 165 ° C, the steam pressure is 1 MPa, and after vulcanization for 25 minutes, it is cooled, cored, trimmed, inspected, and stored in the warehouse to obtain a car radiator hose. The rubber composition used for the inner rubber layer was the rubber composition used in Example 7.

Example 14

An automobile radiator hose, wherein the rubber composition used for the outer rubber layer is the rubber composition used in the seventh embodiment. The production process flow is the same as that in the embodiment 13.

Example 15

An automobile radiator hose, wherein the rubber composition for the inner rubber layer and the outer rubber layer is the rubber composition used in the seventh embodiment. The production process is the same as in Example 13.

Example 16:

An air-conditioning hose, wherein the rubber composition used for the inner rubber layer is the rubber composition used in the embodiment 9. The production process is as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 60 ° C, the rotor speed to 50 rpm, add 30 parts of ethylene propylene diene rubber and 70 parts of branched polyethylene pre-pressure mixing for 90 seconds; add 5 parts of oxidation Zinc, 1 part stearic acid, 2 parts PEG4000, 1 part antioxidant RD, kneaded for 30 seconds; then add 30 parts carbon black N550, 50 parts carbon black N774, 15 parts paraffin oil SUNPAR2280 in the rubber compound, mix 3 Minute; finally added 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of cross-linking agent N, N'-m-phenylene bismaleimide (HVA-2), 0.3 parts of cross-linking Sulphur, glued for 2 minutes and then discharged. The mixture is thinned on the open mill and then placed on the sheet to be vulcanized.

(3) Vulcanization: The vulcanization process is applied, the temperature is 165 ° C, the steam pressure is 1 MPa, the vulcanization time is 25 minutes, and then the cloth is uncoated, cored off, and cut off. Get the air conditioning hose.

Example 17

An air-conditioning hose whose rubber composition for the outer rubber layer is the rubber composition used in the ninth embodiment. The production process is the same as in Example 16.

Example 18

An air-conditioning hose, wherein the rubber composition used for the inner rubber layer and the outer rubber layer is the rubber composition used in the embodiment 9. The production process is the same as in Example 16.

Example 19

A rubber hose assembly whose production process is as follows:

(1) rubber compound: inner rubber layer rubber composition composition and content: 100 parts of branched polyethylene PER-4, 1 part of antioxidant RD, 80 parts of carbon black N550, 20 parts of calcium carbonate, 40 parts of paraffin oil SUNPAR2280, 3 parts of dicumyl peroxide (DCP) and 1 part of N,N'-m-phenylene bismaleimide. The composition and content of the rubber composition of the outer rubber layer are: 100 parts of branched polyethylene PER-4, 1 part of antioxidant RD, 80 parts of carbon black N550, 20 parts of calcium carbonate, 50 parts of paraffin oil SUNPAR 2280, 3 parts of dioxygen peroxide Propylene (DCP) and 1 part of N,N'-m-phenylene bismaleimide.

The raw materials of the inner rubber layer and the outer rubber layer are respectively processed into an inner layer rubber mixture and an outer layer rubber mixture by an open mill or an internal mixer, and the impurities are filtered out after passing the test;

Example 20

An air conditioning hose, wherein the rubber composition used for the inner rubber layer and the outer rubber layer is the same rubber composition. The production process is as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 60 ° C, the rotor speed to 50 rpm, add 100 parts of branched polyethylene PER-10 pre-pressure mixing for 90 seconds; add 5 parts of zinc oxide, 1 part of hard Fatty acid, 2 parts PEG4000, 1 part antioxidant MB, mixed for 30 seconds; then add 30 parts carbon black N550, 50 parts carbon black N774, 15 parts paraffin oil SUNPAR2280 in the rubber compound, mix for 3 minutes; finally add 3 Cross-linking agent dicumyl peroxide (DCP), 1 part of cross-linking agent N, N'-m-phenylene bismaleimide (HVA-2), 0.3 parts of cross-linking agent sulfur, mixing Discharge the glue after 2 minutes. The mixture is thinned on the open mill and then placed on the sheet to be vulcanized.

(3) Vulcanization: using a cloth vulcanization process, the temperature is 165 ° C, the steam pressure is 1 MPa, the vulcanization time is 25 minutes, and then the cloth is uncoated, cored off, and cut off. Get the air conditioning hose.

The rubber composition of the present embodiment was molded into a test sample by molding, and the test performance was as follows:

Hardness: 68; tensile strength: 26.3 MPa; elongation at break: 468%; tear strength: 60 N/mm.

Example 21

The utility model relates to an automobile radiator hose, wherein the rubber composition used for the inner rubber layer and the outer rubber layer is the same rubber composition. The production process is as follows:

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of branched polyethylene PER-11 pre-pressing and kneading for 90 seconds; add 2 parts of PEG4000, 1 part of anti-aging agent MB, 1 part of antioxidant RD, 3 parts of solid coumarone, mixing for 30 seconds; then add 70 parts of carbon black N550, 15 parts of paraffin oil SUNPAR2280 in the compound, mixing for 3 minutes; finally adding 3 parts of crosslinking agent Dicumyl peroxide (DCP), 1 part of the co-crosslinking agent, triallyl isocyanurate (TAIC), was kneaded for 2 minutes and then discharged. The mixture is thinned on the open mill and then placed on the sheet to be vulcanized.

(3) Vulcanization: The mandrel is inserted into the tube blank, vulcanized by high temperature steam, the temperature is 165 ° C, the steam pressure is 1 MPa, and after vulcanization for 25 minutes, it is cooled, cored, trimmed, inspected and stored, and the automobile radiator hose is obtained.

Hardness: 66; tensile strength: 27.8 MPa; elongation at break: 532%; tear strength: 62 N/mm.

Example 22

(1) Rubber mixing: set the temperature of the internal mixer to 90 ° C, the rotor speed is 50 rpm, add 100 parts of branched polyethylene PER-12 pre-pressure mixing for 90 seconds; add 2 parts of PEG4000, 1 part of antioxidant MB, 2 parts solid coumarone, 3 parts modified alkyl phenolic resin TKM-M, compounded for 30 seconds; then add 80 parts of carbon black N550, 20 parts of paraffin oil SUNPAR2280 to the compound, and mix for 3 minutes; 3 parts of cross-linking agent dicumyl peroxide (DCP), 1 part of the cross-linking agent triallyl isocyanurate (TAIC) were added, and the mixture was kneaded for 2 minutes and then discharged. The mixture is thinned on the open mill and then placed on the sheet to be vulcanized.

Hardness: 65; tensile strength: 25.4 MPa; elongation at break: 488%; tear strength: 58 N/mm.

As can be seen from the performance comparison of the above examples and comparative examples, the rubber composition containing the branched polyethylene has higher tensile strength and tearing properties under the same or similar conditions of the other formulation components. The use of such a rubber composition as a raw material for the production of a hose can significantly reduce the probability of tearing of the hose during production and use. At the same time, its resistance to 150 °C hot air aging is maintained at the same level as the rubber composition of ethylene propylene rubber alone, which can meet the high temperature resistance requirements of the current similar radiator hoses and air conditioning hoses.

The superiority of the branched polyethylene in cross-linking ability is demonstrated by the cross-linking performance test comparison of Examples 23 and 24 and Comparative Example 3.

The rubber substrate used in Example 23 was 100 parts of PER-9, and the rubber substrate used in Example 24 was 50 parts of PER-9 and 50 parts of ethylene propylene diene monomer (ML (1+4) 125 ° C was 80, and the ethylene content was 55. %, ENB content 5.5%), the rubber substrate used in Comparative Example 3 was 100 parts of the ethylene propylene diene rubber used in Example 24. 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 rotor rotation speed is 50 rpm, adding a rubber matrix pre-pressing and kneading for 90 seconds; adding 5 parts of zinc oxide, 1 part of stearic acid, and kneading for 1 minute;

(2) then adding 80 parts of carbon black N550, 10 parts of calcium carbonate, 60 parts of paraffin oil to the 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:

	实施例23Example 23	实施例24Example 24	对照例3Comparative Example 3
ML,dN.mML, dN.m	2.022.02	1.201.20	0.60.6
MH,dN.mMH, dN.m	12.7412.74	11.9411.94	11.2311.23
MH-ML,dN.mMH-ML, dN.m	10.7210.72	10.7410.74	10.6310.63
Tc90,minTc90,min	6.86.8	7.57.5	8.28.2

The rubber composition of Example 19 has the shortest Tc90 and the MH-ML value is higher than that of Comparative Example 3, indicating that the branched polyethylene used in the present embodiment can be slightly superior in cross-linking ability to the conventional EPDM rubber. The Tc90 of Example 20 was between Example 19 and Comparative Example 3, and the MH-ML of Example 20 was larger than that of Example 19 and Comparative Example 3, indicating that the combination of both was expected to increase the overall crosslinking density.

Although preferred embodiments of the invention have been described herein, these embodiments are provided by way of example only. It will be appreciated that variations of the embodiments of the invention described herein may also be used in the practice of the invention. It will be appreciated by those skilled in the art that various modifications, changes and substitutions may be made without departing from the scope of the invention. It is to be understood that the scope of the present invention is defined by the scope of the claims, and the scope of the appended claims.

Claims

A rubber composition comprising, in parts by weight, a rubber matrix and an essential component, the rubber matrix comprising:

The content a of the branched polyethylene is: 0 < a ≤ 100 parts,

The content b of the binary ethylene propylene rubber and the ethylene propylene diene rubber is: 0 ≤ b < 100 parts;

The essential component comprises: 1.5 to 8 parts of a crosslinking agent, 50 to 200 parts of a reinforcing filler, and 10 to 100 parts of a plasticizer, wherein the branched polyethylene contains ethylene, based on 100 parts by weight of the rubber substrate. The homopolymer has 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 of ML (1+4) of not lower than 2 at 125 °C.
The rubber composition according to claim 1, wherein the rubber matrix contains the content of the branched polyethylene in an amount of 100 parts by weight: 10 ≤ a ≤ 100 parts, and the ethylene propylene rubber and the EPDM. The content of rubber b: 0 ≤ b ≤ 90 parts; wherein, the branched polyethylene is an ethylene homopolymer, the degree of branching is 60 to 130 branches / 1000 carbons, and the weight average molecular weight is 66,000 to 518,000. Mooney viscosity ML (1 + 4) 125 ° C is 6 ~ 102.
The rubber composition according to claim 1, wherein the crosslinking agent comprises at least one of a sulfur or a peroxide crosslinking agent, wherein the peroxide crosslinking agent comprises di-tert-butyl group. Peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 2,5-di Methyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, bis(tert-butylperoxide) Isopropyl)benzene, 2,5-dimethyl-2,5-bis(benzoyl peroxy)hexane, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexyl carbonate At least one of them.
The rubber composition according to claim 1, wherein the reinforcing filler comprises carbon black, calcium carbonate, calcined clay, magnesium silicate, aluminum silicate, magnesium carbonate, talc, diatomaceous earth. At least one.
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 And at least one of dioctyl sebacate.
The rubber composition according to claim 1, wherein the rubber composition further comprises an auxiliary component based on 100 parts by weight of the rubber base, and the auxiliary component is in parts by weight, which comprises: a co-crosslinking agent 0.2 to 8 Parts, metal oxide 2 to 15 parts, stabilizer 1 to 3 parts, polyethylene glycol 1 to 5 parts, vulcanization accelerator 0 to 3 parts,

The co-crosslinking agent comprises triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, ethyl dimethacrylate, triethylene glycol dimethacrylate , triallyl trimellitate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, N, N'-m-phenylene bismaleimide, N, N'- At least one of bis-indenyl acetonide, 1,2-polybutadiene, a metal salt of an unsaturated carboxylic acid, and sulfur;

The metal oxide comprises at least one of zinc oxide, magnesium oxide, and calcium oxide;

The stabilizer comprises 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 6-ethoxy-2,2,4-trimethyl-1,2-di At least one of hydrogenated quinoline (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, dibenzothiazyl disulfide, tetramethylthiuram monosulfide, tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, two Zinc n-butyldithiocarbamate, N-cyclohexyl-2-benzothiazolyl sulfenamide, N,N-dicyclohexyl-2-benzothiazolyl sulfenamide, bismaleimide, sub At least one of ethyl thiourea.
A method of processing the rubber composition according to any one of claims 1 to 6, wherein the processing method comprises the steps of:

(1) setting the temperature of the internal mixer and the rotation speed of the rotor, and sequentially adding the components other than the crosslinking system of the rubber component to the internal mixer; then adding the crosslinking system, and then discharging the rubber after mixing, wherein The crosslinking system comprises a crosslinking agent, and may further comprise at least one of a co-crosslinking agent and a vulcanization accelerator;

(2) The rubber compound obtained in the step (1) is thinly passed on the open mill, and the lower piece is placed and parked;

(3) The rubber compound is filled into the cavity of the mold, heated and pressurized on a flat vulcanizer, and then released to obtain a vulcanized rubber.
A hose characterized in that the rubber composition comprises the rubber composition according to any one of claims 1 to 6.
A method of producing the hose of claim 8, characterized in that the production method comprises the following steps:

(1) Rubber kneading: firstly, the rubber components other than the cross-linking system are sequentially added to the internal mixer according to the parts by weight for kneading, and then added to the cross-linking system, which is uniformly kneaded and discharged to obtain a rubber compound. After the mixture is thinned on the open mill, the tablet is left to be vulcanized, wherein the crosslinking system comprises a crosslinking agent, and may further comprise at least one of a crosslinking agent and a vulcanization accelerator;

(2) Extrusion and molding: a cold feed extruder is used to extrude the rubber layer on the mandrel to obtain a tube blank, which is cooled by steam vulcanization, de-core, trimmed, inspected, and stored in a warehouse to obtain a hose.
An automobile radiator hose, characterized in that at least one of an inner rubber layer and an outer rubber layer of the automobile radiator hose comprises the rubber composition according to any one of claims 1 to 6.
A method for producing a car radiator hose according to claim 10, comprising the steps of:

(1) Rubber kneading: setting the appropriate temperature of the internal mixer and the rotor rotation speed, adding the rubber components other than the crosslinking system to the internal mixer in order of mixing, and then adding the crosslinking system to the mixture. After being uniformly discharged, a rubber mixture is obtained, and the rubber compound is thinned on the open mill and then left to be left to be vulcanized, wherein the crosslinking system contains a crosslinking agent, and may further comprise a crosslinking agent and a vulcanization accelerator. At least one

(2) Extrusion and molding: using a cold feed extruder, extruding the inner rubber layer, then knitting the fiber reinforced layer on the inner rubber layer, and then extruding the outer rubber layer to obtain a tube blank, and cutting the vulcanization;

(3) Vulcanization: The mandrel is inserted into the tube blank, cooled by steam vulcanization, de-core, trimmed, inspected, and stored in the warehouse to obtain a car radiator hose.
An air-conditioning hose characterized in that at least one of an inner rubber layer and an outer rubber layer of the air-conditioning hose comprises the rubber composition according to any one of claims 1 to 6.
A method of producing the air-conditioning hose of claim 12, comprising the steps of:

(1) Rubber mixing: set the appropriate temperature of the internal mixer and the rotor speed, and add the rubber components other than the cross-linking system to the internal mixer for mixing, and then add the cross-linking system to be kneaded. After being uniformly discharged, a rubber mixture is obtained, and the rubber compound is thinned on the open mill and then left to be left to be vulcanized, wherein the crosslinking system contains a crosslinking agent, and may further comprise a crosslinking agent and a vulcanization accelerator. At least one

(2) Extrusion and molding: preparing a mandrel, extruding a nylon alloy lining on the mandrel, extruding the inner rubber layer, weaving the fiber reinforced layer, and then extruding the outer rubber layer;

(3) Vulcanization: the cloth is vulcanized, uncoated, uncored, and cut off to obtain an air-conditioning hose.
A rubber hose assembly characterized in that at least one of the inner rubber layer and the outer rubber layer comprises the rubber composition according to any one of claims 1 to 6.
A method of producing the hose assembly of claim 14 comprising the steps of:

(1) rubber mixing: the raw materials of the inner rubber layer and the outer rubber layer are respectively processed into an inner layer rubber mixture and an outer layer rubber mixture by an open mill or an internal mixer, and the impurities are filtered out after passing the test;

(2) Tube blank forming: the inner rubber layer is extruded by a cold feed extruder, and the aramid fiber layer is knitted on the outer surface of the inner rubber layer, and finally the outer rubber compound is extruded through an outer rubber layer extruder. And coating on the outer surface of the aramid fiber layer to form a tube blank;

(3) vulcanization: the above tube blank is placed on the tube core, placed in a steam vulcanization tank, steam is pressurized to 0.9 MPa, heated to 175 ° C, and vulcanized for 25 minutes to obtain a vulcanized rubber hose;

(4) Loading the clamp: After cleaning and cutting the above vulcanized rubber hose, the pre-opening clamp is bonded at both ends of each hose to obtain a rubber hose assembly.