CN112608528A - Rubber composition for bonding steel cord and conveyor belt - Google Patents
Rubber composition for bonding steel cord and conveyor belt Download PDFInfo
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- CN112608528A CN112608528A CN202011001699.5A CN202011001699A CN112608528A CN 112608528 A CN112608528 A CN 112608528A CN 202011001699 A CN202011001699 A CN 202011001699A CN 112608528 A CN112608528 A CN 112608528A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L7/00—Compositions of natural rubber
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G15/00—Conveyors having endless load-conveying surfaces, i.e. belts and like continuous members, to which tractive effort is transmitted by means other than endless driving elements of similar configuration
- B65G15/30—Belts or like endless load-carriers
- B65G15/32—Belts or like endless load-carriers made of rubber or plastics
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- C08L9/06—Copolymers with styrene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
- C08K2003/2296—Oxides; Hydroxides of metals of zinc
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
- C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
Abstract
The invention provides a rubber composition for bonding a steel cord, which has excellent water-resistant adhesion, and a conveyor belt. The rubber composition for bonding a steel cord comprises: a rubber component containing at least a diene rubber; rosins; diethylene glycol; a vulcanization accelerator; organic acid cobalt salts; and sulfur, wherein the content of the rosin is 1.0 to 12.0 parts by mass relative to 100 parts by mass of the rubber component, and the content of the diethylene glycol is 0.3 to 2.5 parts by mass relative to 100 parts by mass of the rubber component.
Description
Technical Field
The present invention relates to a rubber composition for bonding steel cords and a conveyor belt.
Background
Conventionally, various rubber compositions have been proposed for the purpose of improving adhesion to a steel cord and the like.
For example, patent document 1 describes a method for bonding a galvanized steel cord and a rubber, in which a rubber composition containing 3 to 15 parts by weight of rosin or a rosin derivative, 0.2 to 1.0 part by weight of an organic cobalt salt in terms of the amount of cobalt, and 3 to 50 parts by weight of an organic chlorine compound are bonded to a galvanized steel cord, based on 100 parts by weight of a sulfur-vulcanizable rubber.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 11-21389
Disclosure of Invention
Problems to be solved by the invention
In this case, the present inventors prepared a rubber composition and evaluated it as a rubber composition for bonding a steel cord with reference to patent document 1, and found that: the water-resistant adhesion between the rubber obtained by vulcanizing such a rubber composition and the steel cord is still in the room for improvement not only in the case where the vulcanization is appropriate but also in the case where the vulcanization is excessive.
Accordingly, an object of the present invention is to provide a rubber composition for bonding a steel cord, which is excellent in water-resistant adhesion even in the case of overcuring. In the present invention, the water-resistant adhesion includes moisture-resistant adhesion. In the present invention, the rubber composition may be excellent in water-resistant adhesion when it is vulcanized to be over-vulcanized, or may be simply referred to as "excellent in water-resistant adhesion".
The present invention also aims to provide a conveyor belt having excellent water-resistant adhesion.
Means for solving the problems
The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that the water-resistant adhesion between the rubber obtained from the rubber composition and the steel cord can be improved regardless of whether the vulcanization of the rubber composition is an overcuring (proper vulcanization or even if the vulcanization is an overcuring) by using a rubber composition for steel cord adhesion comprising: a rubber component containing at least a diene rubber; rosins; diethylene glycol; a vulcanization accelerator; organic acid cobalt salts; and sulfur, wherein the content of the rosin is 1.0 to 12.0 parts by mass relative to 100 parts by mass of the rubber component, and the content of the diethylene glycol is 0.3 to 2.5 parts by mass relative to 100 parts by mass of the rubber component.
The present invention solves the above problems based on the above findings and the like, specifically, with the following configurations.
[1] A rubber composition for bonding a steel cord, comprising:
a rubber component containing at least a diene rubber;
rosins;
diethylene glycol;
a vulcanization accelerator;
organic acid cobalt salts; and
the amount of sulfur is such that,
the content of the rosin is 1.0-12.0 parts by mass relative to 100 parts by mass of the rubber component,
the content of the diethylene glycol is 0.3 to 2.5 parts by mass with respect to 100 parts by mass of the rubber component.
[2] The rubber composition for bonding a steel cord according to [1], wherein the organic acid cobalt salt contains cobalt neodecanoate borate.
[3] The rubber composition for bonding a steel cord according to [1] or [2], wherein the softening point of the rosin is 40 to 130 ℃ or the acid value of the rosin is 50 to 200 mgKOH/g.
[4] The rubber composition for adhesion of steel cord according to any one of [1] to [3], wherein the vulcanization accelerator contains a benzothiazole-based vulcanization accelerator.
[5] The rubber composition for adhesion of steel cord according to any one of [1] to [4], wherein the content of the vulcanization accelerator is 2.0 parts by mass or less with respect to 100 parts by mass of the rubber component.
[6] The rubber composition for steel cord adhesion according to any one of [1] to [5], which is used for adhesion of a galvanized steel cord.
[7] A conveyor belt formed by using the rubber composition for bonding steel cords according to any one of [1] to [6 ].
ADVANTAGEOUS EFFECTS OF INVENTION
The rubber composition for bonding a steel cord of the present invention has excellent water-resistant adhesion.
The conveyor belt of the present invention is excellent in water-resistant adhesion.
Drawings
Fig. 1 is a sectional perspective view schematically showing an example of a conveyor belt according to the present invention.
Detailed Description
The present invention will be described in detail below.
In the present specification, the numerical range expressed by the term "to" means a range including the numerical values described before and after the term "to" as the lower limit value and the upper limit value.
In the present specification, unless otherwise specified, each component may be used alone or in combination of 2 or more kinds of the substances corresponding to the component. When the component contains 2 or more substances, the content of the component means the total content of the 2 or more substances.
In the present specification, the method for producing each component is not particularly limited as long as it is not particularly specified. For example, a conventionally known method can be used.
In the present specification, the fact that the water-resistant adhesion is more excellent (even when the vulcanization of the rubber composition is an overcuring) may be referred to as the fact that the effect of the present invention is more excellent.
[ rubber composition for adhesion of Steel cord ]
The rubber composition for bonding a steel cord of the present invention (the composition of the present invention) is a rubber composition for bonding a steel cord, comprising:
a rubber component containing at least a diene rubber;
rosins;
diethylene glycol;
a vulcanization accelerator;
organic acid cobalt salts; and
the amount of sulfur is such that,
the content of the rosin is 1.0-12.0 parts by mass relative to 100 parts by mass of the rubber component,
the content of the diethylene glycol is 0.3 to 2.5 parts by mass with respect to 100 parts by mass of the rubber component.
It is considered that the composition of the present invention has the above-described structure, and therefore, the desired effects can be obtained. The reason for this is not clear, and is presumed to be as follows.
It is considered that the composition of the present invention also has excellent water-resistant adhesion by containing the rosin and diethylene glycol (DEG).
The rosin is considered to have a function of reducing (removing) a metal oxide (for example, zinc oxide) on the surface of the steel cord, and contributes to the reaction between the composition of the present invention and the surface of the steel cord.
The present inventors speculate that the reaction efficiency of the composition of the present invention with the surface of the steel cord can be improved by using DEG in combination with rosins having such a function, whereby DEG improves the reaction stability of rosin acid at the time of production or vulcanization of the composition of the present invention.
The components contained in the composition of the present invention will be described in detail below.
< rubber component >
The composition of the present invention contains a rubber component containing at least a diene rubber.
< diene rubber >
The diene rubber contained in the composition of the present invention is not particularly limited as long as it is a polymer obtained by polymerizing a diene monomer.
Examples of the diene rubber include natural rubber, Isoprene Rubber (IR), aromatic vinyl compound-conjugated diene copolymer rubber (e.g., styrene butadiene copolymer rubber), nitrile rubber (NBR), butyl rubber (IIR), halogenated butyl rubber, and Chloroprene Rubber (CR).
The diene rubber is preferably natural rubber, Isoprene Rubber (IR), or an aromatic vinyl compound-conjugated diene copolymer rubber (for example, styrene butadiene copolymer rubber), and more preferably a combination of natural rubber and an aromatic vinyl compound-conjugated diene copolymer rubber (particularly, styrene butadiene copolymer rubber), natural rubber, or Isoprene Rubber (IR), from the viewpoint that the effect of the present invention is more excellent and the durability is excellent.
Natural rubber
The Natural Rubber (NR) is not particularly limited. Examples thereof include those conventionally known.
Isoprene rubber
The isoprene rubber is not particularly limited as long as it is a homopolymer of isoprene. Examples thereof include those conventionally known.
Styrene butadiene copolymer rubber
The styrene-butadiene copolymer rubber is not particularly limited as long as it is a copolymer of styrene and butadiene.
(bound styrene amount of styrene butadiene copolymer rubber)
From the viewpoint of further improving the effect of the present invention and lowering the glass transition temperature of the styrene-butadiene copolymer rubber described later, the amount of bound styrene in the styrene-butadiene copolymer rubber is preferably 5 to 40% by mass, and more preferably 10 to 30% by mass, based on the total amount of the styrene-butadiene copolymer rubber.
(vinyl amount of styrene butadiene copolymer rubber)
From the viewpoint of further improving the effect of the present invention and lowering the glass transition temperature of the styrene-butadiene copolymer rubber described later, the vinyl content (1, 2-vinyl bond content) derived from butadiene in the styrene-butadiene copolymer rubber is preferably 5 to 30% by mass, more preferably 5 to 20% by mass, based on the total amount of repeating units derived from butadiene in the styrene-butadiene copolymer rubber.
In the present invention, the amount of the bound styrene and the amount of the vinyl group in the styrene-butadiene copolymer rubber may be determined by1H-NMR measurement.
(weight average molecular weight of styrene butadiene copolymer rubber)
The weight average molecular weight of the styrene butadiene copolymer rubber is not particularly limited. And may be, for example, 20 to 300 ten thousand.
In the present invention, the weight average molecular weight of the styrene butadiene copolymer rubber is a standard polystyrene equivalent value based on a measurement value obtained by Gel Permeation Chromatography (GPC) using tetrahydrofuran as a solvent.
(S-SBR)
The method for producing the styrene-butadiene copolymer rubber is not particularly limited. Examples thereof include styrene butadiene copolymer rubber (S-SBR) obtained by solution polymerization and styrene butadiene copolymer rubber (E-SBR) obtained by emulsion polymerization. Among these, the styrene-butadiene copolymer rubber preferably contains S-SBR, from the viewpoint that the effect of the present invention is more excellent.
The S-SBR is not particularly limited as long as it is produced by copolymerizing styrene and butadiene in an organic solvent in the presence of a catalyst. Examples of S-SBR include conventionally known ones.
Further, the above solution polymerization is not particularly limited. Examples thereof include conventionally known ones.
So long as all or a part of the rubber component is a diene rubber. One preferable embodiment is one in which all of the rubber components are diene rubbers.
The content of the diene rubber is preferably 70 to 100 parts by mass per 100 parts by mass of the rubber component.
In the case where the rubber component contains the natural rubber and the styrene-butadiene copolymer rubber, the content of the natural rubber is preferably 20 to 80 parts by mass, and more preferably 30 to 70 parts by mass, per 100 parts by mass of the rubber component, from the viewpoint of further improving the effect of the present invention.
The content of the styrene-butadiene copolymer rubber may be an amount obtained by removing the content of the natural rubber from 100 parts by mass of the rubber component.
When the rubber component contains a rubber other than a diene rubber, examples of the rubber other than a diene rubber include non-diene rubbers such as ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM).
< rosins >
The composition of the present invention contains rosins.
Examples of the rosin include rosin and rosin derivatives.
Rosin (R)
Rosin is generally a natural resin obtained by distilling rosin or the like.
When rosin is exemplified from the viewpoint of the above-mentioned production, examples of the rosin include gum rosin (gum rosin), wood rosin (wood rosin), and tall rosin (tall rosin).
The rosin (among gum rosin, wood rosin, and tall oil rosin) is preferably gum rosin, from the viewpoint that the effect of the present invention is more excellent.
Furthermore, rosin generally comprises resin acids.
Examples of the resin acid include abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, and dehydroabietic acid.
The various resin acids described above are common in that they have a carboxyl group as a functional group.
The rosin may contain at least 1 selected from abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, and dehydroabietic acid. Further, the rosin may be a mixture containing at least 2 or more selected from the above group.
Further, the ratio of the resin acid component generally varies depending on the kind of rosin such as gum rosin.
Rosin derivatives
Examples of the rosin derivative (modified rosin) include compounds obtained by acid-modifying, disproportionating (double-bonding), hydrogenating, dimerizing, or esterifying the resin acid.
The rosin preferably contains rosin from the viewpoint of further improving the effect of the present invention.
Softening point of rosins
The softening point of the rosin is preferably 40 to 130 ℃, and more preferably 50 to 100 ℃ from the viewpoint of further enhancing the effect of the present invention.
The softening point of the rosin can be measured according to JIS K5902-1969.
Acid value of rosins
From the viewpoint of further improving the effect of the present invention, the acid value of the rosin is preferably 50 to 200mgKOH/g, and more preferably 80 to 180 mgKOH/g.
The acid value of the rosin can be determined in accordance with JIS K2501: 2003.
Molecular weight of rosins
The molecular weight of the rosin is preferably 200 to 1000, more preferably 250 to 400, from the viewpoint of further improving the effect of the present invention.
The molecular weight of rosins can be determined by Gel Permeation Chromatography (GPC).
Since rosins are generally a mixture, the molecular weights of the rosins may be average values.
< content of rosin >
In the present invention, the content of the rosin is 1.0 to 12.0 parts by mass with respect to 100 parts by mass of the rubber component.
From the viewpoint of further improving the effect of the present invention, the content of the rosin is preferably 4 to 9 parts by mass per 100 parts by mass of the rubber component.
< diethylene glycol >
The compositions of the present invention contain diethylene glycol.
The present invention uses a combination of abietic acid and diethylene glycol, and thus has excellent water-resistant adhesion.
The compositions of the present invention contain diethylene glycol (HO-CH)2CH2-O-CH2CH2-OH) is not particularly limited. The diethylene glycol may be, for example, a monomer of diethylene glycol, or may be a mixture of diethylene glycol and silica (a blend of the two mixed in advance).
Content of diethylene glycol
In the present invention, the content of diethylene glycol is 0.3 to 2.5 parts by mass with respect to 100 parts by mass of the rubber component.
When the content of diethylene glycol is in the above range, the water resistant adhesion is excellent. If the content of diethylene glycol exceeds 2.5 parts by mass with respect to 100 parts by mass of the rubber component, the water-resistant adhesion becomes low.
From the viewpoint of the more excellent effect and the excellent durability of the present invention, the content of diethylene glycol is preferably 0.4 to 2.0 parts by mass, more preferably more than 0.5 part by mass and 1.5 parts by mass or less, per 100 parts by mass of the rubber component.
< vulcanization accelerator >
The composition of the present invention contains a vulcanization accelerator.
The vulcanization accelerator contained in the composition of the present invention is not particularly limited as long as it can be used in a rubber composition that can be vulcanized by sulfur.
Examples of the vulcanization accelerator include aldehyde-ammonia type, aldehyde-amine type, thiourea type, guanidine type, thiazole type, sulfenamide type, thiuram type, dithiocarbamate type, xanthate type, and a mixture thereof.
In general, when a vulcanization accelerator classified as a vulcanization accelerator other than thiazole has a thiazole skeleton, the vulcanization accelerator as described above is classified as a thiazole-based vulcanization accelerator in the present specification.
From the viewpoint of more excellent water-resistant adhesion, the vulcanization accelerator preferably contains a thiazole-based vulcanization accelerator, and more preferably contains a benzothiazole-based vulcanization accelerator.
The thiazole-based vulcanization accelerator is not particularly limited as long as it is a vulcanization accelerator having a thiazole skeleton. Examples of the thiazole-based vulcanization accelerator include a benzothiazole-based vulcanization accelerator having a benzothiazole skeleton.
Vulcanization accelerators having a benzothiazolylthioether group
Examples of the benzothiazole-based vulcanization accelerator include a vulcanization accelerator having a benzothiazyl sulfide group.
The benzothiazolyl sulfide group can be represented by the following structure, for example. In addition, in the following structures, a hydrogen atom in the benzothiazole ring may be substituted with a substituent. The substituent is not particularly limited.
In the benzothiazolyl sulfide group represented by the above structure, a sulfur atom not constituting a ring structure may constitute, for example, — SH (mercapto group); a linker (e.g., a 2-or 3-valent linker) such as a (poly) sulfide bond or a sulfonamide bond (e.g., -S-NH-, -S-N <); for example, the salt may be formed with a metal such as zinc or an alkali metal such as sodium.
In the case where the benzothiazolyl sulfide group has the above-mentioned linking group, a group to be further bonded to the above-mentioned linking group is not particularly limited. Examples thereof include hydrocarbon groups which may have hetero atoms such as oxygen, nitrogen and sulfur. Examples of the hydrocarbon group include an aliphatic hydrocarbon group (including linear, branched, and cyclic), an aromatic hydrocarbon group, a heterocyclic ring, and a combination thereof.
Examples of the benzothiazolyl sulfide group in which a sulfur atom not constituting a ring structure constitutes a sulfenamide bond (a benzothiazole-based vulcanization accelerator having a sulfenamide bond) include N-cyclohexyl-2-benzothiazolyl sulfenamide, N-tert-butyl-2-benzothiazolyl sulfenamide, N-oxydiethylene-2-benzothiazolyl sulfenamide, N-diisopropyl-2-benzothiazolyl sulfenamide, and N, N-dicyclohexyl-2-benzothiazyl sulfenamide.
From the viewpoint of more excellent water-resistant adhesion, the vulcanization accelerator (or the benzothiazole-based vulcanization accelerator) preferably contains benzothiazole having a mercapto group or a polysulfide bond, or mercaptobenzothiazole which forms a salt with a metal or an alkali metal.
Examples of the benzothiazole having a mercapto group include 2-mercaptobenzothiazole (the following structure).
Examples of the benzothiazole having a polysulfide bond include benzothiazoles having a disulfide bond such as bis-2-benzothiazolylthiodisulfide (the following structure).
Examples of mercaptobenzothiazoles which form salts with metals or alkali metals include zinc salts of 2-mercaptobenzothiazole (the following structure),
Sodium salt of 2-mercaptobenzothiazole (structure below).
From the viewpoint of more excellent water-resistant adhesion, the vulcanization accelerator (or the benzothiazole-based vulcanization accelerator) is preferably 2-mercaptobenzothiazole, di-2-benzothiazyl disulfide, or a zinc salt of 2-mercaptobenzothiazole, and more preferably di-2-benzothiazyl disulfide.
(content of vulcanization accelerator)
From the viewpoint of more excellent water-resistant adhesion, the content of the vulcanization accelerator is preferably 2.0 parts by mass or less, and more preferably 0.1 to 0.8 parts by mass, per 100 parts by mass of the rubber component.
Organic acid cobalt salt
The organic acid cobalt salt contained in the composition of the present invention is not particularly limited as long as it is a salt formed from an organic acid and cobalt.
(organic acid)
Examples of the organic acid constituting the organic acid cobalt salt include compounds having a carboxyl group. The above carboxyl group may be combined with an organic group. The organic group is not particularly limited. Examples thereof include hydrocarbon groups. Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a combination thereof.
Examples of the aliphatic hydrocarbon group include straight chain, branched chain, cyclic, and combinations thereof. The aliphatic hydrocarbon group may have an unsaturated bond.
(Carboxylic acid ion)
When the organic acid forming the organic acid cobalt salt is a compound having a carboxyl group, the organic acid cobalt salt may have a carboxyl ion (-COO) derived from the carboxyl group of the organic acid-)。
(cobalt ion)
In the above-mentioned organic acid cobalt salt, the counter ion of the anion (formed by an acid) such as the above-mentioned carboxyl ion is that possessed by the organic acid cobalt saltCobalt ion (e.g. Co)2+、Co3+)。
Examples of the organic acid cobalt salt include organic acid cobalt salts containing no boron, such as cobalt naphthenate, cobalt stearate, cobalt octylate, and cobalt neodecanoate;
and a cobalt boron complex compound such as cobalt neodecanoate borate represented by the following formula (1).
From the viewpoint of the superior effect and the superior durability of the present invention, the organic acid cobalt salt is preferably cobalt naphthenate, cobalt neodecanoate, or cobalt borate neodecanoate, more preferably cobalt naphthenate or cobalt borate neodecanoate, and further preferably contains cobalt borate neodecanoate.
The content of cobalt in the organic acid cobalt salt is preferably 0.22 to 1.20 parts by mass, more preferably 0.25 to 0.80 parts by mass, and still more preferably 0.30 to 0.70 parts by mass, per 100 parts by mass of the rubber component.
Organic acid cobalt salt/diethylene glycol
From the viewpoint of further improving the effect of the present invention, the mass ratio of the content of the organic acid cobalt salt to the content of the diethylene glycol (organic acid cobalt salt/diethylene glycol) is preferably 0.4 to 12.0, and more preferably 1.0 to 5.0.
< Sulfur >
The composition of the present invention contains sulfur. The above sulfur is not particularly limited. For example, elemental sulfur may be mentioned.
(content of sulfur)
From the viewpoint of the more excellent effect and the excellent durability of the present invention, the content of the sulfur is preferably 2.1 to 6.0 parts by mass, more preferably 3.5 to 5.0 parts by mass, and still more preferably more than 4.0 parts by mass and 5.0 parts by mass or less with respect to 100 parts by mass of the rubber component.
(phenol resin)
The composition of the present invention may further contain a phenol resin.
From the viewpoint of more excellent water-resistant adhesion, the composition of the present invention preferably further contains a phenol resin.
As the phenol resin, those which can be generally blended in a rubber composition can be used. The phenol resin may include a resin obtained by a reaction of a phenol with an aldehyde and a modified product thereof. Examples of the phenols include phenol, cresol, xylenol, and resorcinol. Examples of the aldehyde include formaldehyde, acetaldehyde, and furfural.
In addition, the composition of the present invention does not contain a curing agent for a phenol resin, which is one of preferable embodiments.
From the viewpoint of the excellent effect and durability of the present invention, the content of the phenol resin is preferably 2 to 8 parts by mass, and more preferably 3 to 7 parts by mass, per 100 parts by mass of the rubber component.
(chlorinated alkane)
The compositions of the invention may also contain chlorinated paraffins.
The composition of the present invention preferably further contains a chloroparaffin from the viewpoint of more excellent water-resistant adhesion.
The chlorinated paraffin is not particularly limited as long as it is a paraffin having chlorine. Examples thereof include chain-like saturated hydrocarbon compounds having 26 carbon atoms on average, in which all or part of the hydrogen atoms in the compounds are substituted with chlorine atoms.
The amount of chlorine contained in the chlorinated paraffin is preferably, for example, 40 to 80% by mass based on the total amount of chlorinated paraffin.
When the composition of the present invention further contains a chloroparaffin, the content of the chloroparaffin is preferably 3 to 8 parts by mass per 100 parts by mass of the rubber component, from the viewpoint of further improving the effects of the present invention and improving the durability.
(carbon Black)
The composition of the present invention may further contain carbon black.
From the viewpoint of more excellent water-resistant adhesion, the composition of the present invention preferably further contains carbon black.
The carbon black is not particularly limited.
Among these, the carbon black is preferably an HAF-grade carbon black or an ISAF-grade carbon black, and more preferably an HAF-grade carbon black, from the viewpoint of further improving the effect of the present invention.
(nitrogen adsorption specific surface area of carbon Black)
From the viewpoint that the effect of the present invention is more excellent, the nitrogen adsorption specific surface area (N) of the carbon black is2SA) is preferably 60 to 120m2A concentration of 65 to 95m is more preferable2/g。
The nitrogen adsorption specific surface area of carbon black can be determined in accordance with JIS K6217-2: 2017 "(2 nd: determination of specific surface area-nitrogen adsorption method-single point method)'.
(content of carbon Black)
From the viewpoint of further improving the effect of the present invention, the content of the carbon black is preferably 35 to 75 parts by mass, and more preferably 40 to 70 parts by mass, based on 100 parts by mass of the rubber component.
(anti-aging agent)
The composition of the present invention may further contain an antioxidant.
The antioxidant is not particularly limited. Examples thereof include conventionally known antioxidants.
From the viewpoint of further improving the effect of the present invention, the content of the antioxidant is preferably 1.0 part by mass or more per 100 parts by mass of the rubber component.
The upper limit of the content of the antioxidant may be 5.0 parts by mass or less with respect to 100 parts by mass of the rubber component.
(Zinc oxide)
The composition of the present invention may further contain zinc oxide. The zinc oxide is not particularly limited.
(content of Zinc oxide)
The upper limit of the content of the zinc oxide may be 20 parts by mass or less with respect to 100 parts by mass of the rubber component.
From the viewpoint of further improving the effect of the present invention, the content of the zinc oxide is preferably 5.0 parts by mass or more, and more preferably 5 to 15 parts by mass, per 100 parts by mass of the rubber component.
The composition of the present invention may contain, if necessary, additives such as stearic acid, fillers other than carbon black, and oils in addition to the above-mentioned essential components within a range not impairing the object of the present invention.
The method for producing the composition of the present invention is not particularly limited. For example, the resin composition can be produced by mixing the above-mentioned essential components, for example, stearic acid, carbon black, and the like, which may be used as needed, with a roll mill, a banbury mixer, a roll, or the like.
The composition of the present invention can be used for example for bonding steel cords (specifically, for example, galvanized steel cords).
By using the composition of the present invention together with a steel cord (e.g., a galvanized steel cord), for example, vulcanization is performed, a composite body having a vulcanized rubber and a steel cord can be obtained. The vulcanized rubber and the steel cord may be bonded to each other in the composite.
Examples of the steel cord include a steel cord; a steel cord obtained by galvanizing a steel cord.
The steel cord is preferably a galvanized steel cord from the viewpoint of further excellent effects and excellent rust prevention properties of the present invention.
The wire diameter, the cord diameter, and the like of the steel cord (including galvanized steel cord, the same applies hereinafter) can be appropriately selected. The above steel cord may be a steel cord whose surface is not treated.
The temperature at which the composition of the present invention is vulcanized may be, for example, about 140 to 160 ℃.
The composition of the present invention can be suitably used for, for example, the production of a conveyor belt. In the case where the composition of the present invention is used for the production of a conveyor belt, the composition of the present invention is preferably formed into a coating rubber layer (e.g., cushion rubber and/or joint rubber) coating a steel cord, for example, as a member constituting the conveyor belt. The 1 coating rubber layer coating the steel cord may have functions of both cushion rubber and joint rubber.
As the cushion rubber, for example, when the conveyor belt has a cover rubber layer, there can be mentioned a rubber adjacent to the cover rubber layer.
Examples of the joint rubber include rubbers capable of connecting the conveyor belt to the end portion, for example. The conveyor belt may be lengthened and/or looped by attachment using a joint rubber.
[ conveyor belt ]
Next, the conveyor belt of the present invention will be explained below.
The conveyor belt of the present invention is formed using the rubber composition for bonding steel cords of the present invention.
It is preferable that the conveyor belt of the present invention has a steel cord. From the viewpoint of further improving the effect of the present invention, it is preferable that the steel cord is a galvanized steel cord.
The rubber composition for bonding a steel cord used for the conveyor belt of the present invention is not particularly limited as long as it is the composition of the present invention.
From the viewpoint that the effect of the present invention is more excellent, it is preferable that the composition of the present invention forms a coating rubber layer (e.g., cushion rubber and/or joint rubber) coating the steel cord.
The conveyor belt of the present invention may preferably further include a rubber coating layer. The rubber composition capable of forming the cover rubber layer is not particularly limited.
In addition, when the coating rubber layer formed using the composition of the present invention is a joint rubber, the cap rubber layers may or may not be adjacent to each other in the coating rubber layer.
The conveyor belt according to the present invention will be described below with reference to the drawings. The conveyor belt of the present invention is not limited to the drawings.
Fig. 1 is a sectional perspective view schematically showing an example of a conveyor belt according to the present invention.
In fig. 1, the conveyor belt 1 has cover rubber layers 6 on both surfaces, and has steel cords 2 and a coating rubber layer 4 between the cover rubber layers 6. The coating rubber layer 4 coats the steel cord 2. The coating rubber layer 4 is preferably formed of the rubber composition for bonding steel cords of the present invention.
Examples
The following examples illustrate the present invention in detail. However, the present invention is not limited thereto.
< production of composition >
The components shown in table 1 below were used in the compositions (parts by mass) shown in the table.
First, among the components shown in table 1 below, components other than sulfur and a vulcanization accelerator were mixed by a banbury mixer to obtain a mixture, and then sulfur and a vulcanization accelerator were added to the mixture in the amounts shown in table 1 and mixed by a roll to produce respective compositions.
In table 1, column 1 of the organic acid cobalt salt, the upper layer is the amount of the organic acid cobalt salt by dry weight, and the lower layer is the amount of cobalt contained in the organic acid cobalt salt.
[ evaluation ]
The following evaluations were made using each composition produced as described above. The results are shown in table 1.
< Water-resistant adhesion >
The water-resistant adhesion was evaluated by the rubber adhesion rate.
< preparation of test body >
Vulcanization under ordinary vulcanization conditions
Each of the compositions prepared as described above was applied to a galvanized steel cord having a diameter of 4.1mm, which was stored in a dryer and subjected to dust-proof and moisture-proof treatment, at a thickness of 15mm to prepare a composite of each composition and the steel cord (a state in which the steel cord was embedded in the composition), and the composite was press-vulcanized by a press molding machine at 153 ℃ and a surface pressure of 2.0MPa for a vulcanization time of 20 minutes to prepare a test piece (rubber/galvanized steel cord composite) under ordinary vulcanization conditions.
Vulcanization under over-vulcanization conditions
A test piece was produced in the same manner as the test piece under the above-mentioned normal vulcanization condition except that the vulcanization time was changed from 20 minutes to 80 minutes, and a test piece under the over vulcanization condition was obtained.
Evaluation method
In the test piece under the above-mentioned normal vulcanization conditions, the boundary between the rubber and the steel cord at the position where the steel cord protrudes from the rubber surface was sealed with beeswax, and the test piece was placed in a constant temperature and humidity bath at a temperature of 50 ℃ and a relative humidity of 95% for 3 weeks.
In the test piece under the above-mentioned overcuring condition, the boundary between the rubber and the steel cord at the position where the steel cord protrudes from the rubber surface was sealed with beeswax, and the test piece was placed in a constant temperature and humidity bath at a temperature of 50 ℃ and a relative humidity of 95% for 5 weeks.
After the test pieces were left in the constant temperature and humidity chamber for the above period, a pull-out test for pulling out the steel cord from each test piece was performed at room temperature (23 ℃). The above-mentioned pull-out test was carried out in accordance with DIN 22131.
After the pull-out test, the state of the pulled-out steel cord was confirmed, and the ratio of the coated area of the rubber remaining on the surface of the steel cord after the pull-out to the surface area of the original steel cord (rubber coating rate,%) was calculated. The rubber coverage calculated as described above is shown in table 1 as the rubber adhesion.
Evaluation criteria
In the present invention, when the rubber adhesion rate (rubber coverage rate) of the test piece under the above-mentioned normal vulcanization condition is 70% or more and the rubber adhesion rate of the test piece under the above-mentioned over-vulcanization condition exceeds 50%, it is evaluated that the water resistant adhesion is excellent regardless of the vulcanization condition (not only in the case where vulcanization is appropriate but also in the case where over-vulcanization is performed).
When the rubber adhesion rate of the test piece under the above-mentioned normal vulcanization condition was less than 70%, or when the rubber adhesion rate of the test piece under the above-mentioned overcuring condition was 50% or less, the water resistant adhesion was evaluated to be poor.
As described above, when the water resistant adhesion is excellent (when the rubber adhesion rate of the test piece under the normal vulcanization condition is 70% or more, and the rubber adhesion rate of the test piece under the over-vulcanization condition exceeds 50%), the water resistant adhesion is evaluated to be more excellent as the rubber adhesion rate of the test piece under the normal vulcanization condition is more than 70%, or the rubber adhesion rate of the test piece under the over-vulcanization condition is more than 50%.
[ Table 1]
The details of each component shown in table 1 are as follows.
(diene rubber)
Diene rubber 1 (NR): natural rubber. TSR20
Diene rubber 2 (SBR): styrene butadiene copolymer rubber was solution polymerized. Trade name タフデン 2000R (manufactured by Asahi Kasei corporation). Glass transition temperature-70 ℃. Weight average molecular weight 32 ten thousand, bound styrene amount 27 mass%, vinyl amount 9 mass%
(rosins)
Rosins 1 (rosin): gum rosin. China rosin WW, manufactured by Mitsui chemical industries, Inc. Softening point: 65 ℃, acid value: 162mgKOH/g, molecular weight: 289
(diethylene glycol)
Diethylene glycol: as diethylene glycol, a product name DST パウダー 1.6.6 (a blend of diethylene glycol and silica 60: 40 (mass ratio)) manufactured by japan ピグメント co. In addition, the amount shown in the diethylene glycol column of table 1 is the amount of diethylene glycol contained in DST パウダー used.
(cobalt salt of organic acid)
Organic acid cobalt salt 1 (cobalt neodecanoate borate): cobalt neodecanoate borate represented by the following formula (1). DICNATE NBC-II (cobalt content in cobalt borate neodecanoate: 22.2% by mass) produced by DIC CORPORATION.
HAF grade carbon black: シヨウブラック N330T (nitrogen adsorption specific surface area 74m, manufactured by キャボットジャパン K.K.)2/g)
Anti-aging agent (OD-3): p, p' -dioctyldiphenylamine represented by the following formula. ノンフレックス OD-3, available from Seiko chemical Co., Ltd.
Phenol resin: スミライトレジン PR-175, Sumitomo デュレズ Kabushiki Kaisha
Chlorinated alkane: chloroparaffins (chlorine content 70 mass%). エンパラ 70S, manufactured by Meizizhisu ファインテクノ.
Zinc oxide: 3 kinds of zinc oxide produced by the same chemical industry society
Stearic acid: stearic acid YR (manufactured by Nichisu oil Co., Ltd.).
(vulcanization accelerators)
Vulcanization accelerator 1 (DM): a benzothiazole-based vulcanization accelerator. Bis-2-benzothiazyl disulfide (structure below). サンセラー DM-PO, (manufactured by Sanxin chemical industry Co., Ltd.)
(Sulfur)
Sulfur: jinhua stamp-pad ink containing sulphur micropowder (produced by Hejian chemical industry Co., Ltd.)
As is clear from the results shown in Table 1, comparative examples 1 and 2 which contained no diethylene glycol had poor water-resistant adhesion.
Comparative example 2, which contained no rosin, was inferior in water-resistant adhesion.
In comparative example 3 in which the content of rosin was out of the predetermined range, the water-resistant adhesion was poor.
In comparative example 4 in which the content of diethylene glycol exceeded the predetermined range, the water-resistant adhesion was poor.
In contrast, the composition of the present invention is excellent in water-resistant adhesion.
Description of the symbols
1 conveyor belt
2 steel cord
4 coating rubber layer
6 covering the rubber layer.
Claims (7)
1. A rubber composition for bonding a steel cord, comprising:
a rubber component containing at least a diene rubber;
rosins;
diethylene glycol;
a vulcanization accelerator;
organic acid cobalt salts; and
the amount of sulfur is such that,
the content of the rosin is 1.0-12.0 parts by mass relative to 100 parts by mass of the rubber component,
the content of the diethylene glycol is 0.3 to 2.5 parts by mass with respect to 100 parts by mass of the rubber component.
2. A rubber composition for adhesion of steel cord according to claim 1, wherein said organic acid cobalt salt comprises cobalt neodecanoate borate.
3. A rubber composition for adhesion of steel cord according to claim 1 or 2, wherein the rosin has a softening point of 40 to 130 ℃ or
The acid value of the rosin is 50-200 mgKOH/g.
4. The rubber composition for steel cord adhesion according to any one of claims 1 to 3, wherein the vulcanization accelerator comprises a benzothiazole vulcanization accelerator.
5. The rubber composition for adhesion of steel cord according to any one of claims 1 to 4, wherein the content of the vulcanization accelerator is 2.0 parts by mass or less with respect to 100 parts by mass of the rubber component.
6. A rubber composition for steel cord adhesion according to any one of claims 1 to 5, which is used for adhesion of a galvanized steel cord.
7. A conveyor belt comprising the rubber composition for bonding steel cord according to any one of claims 1 to 6.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019-182769 | 2019-10-03 | ||
| JP2019182769A JP7287232B2 (en) | 2019-10-03 | 2019-10-03 | Steel cord adhesive rubber composition and conveyor belt |
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| CN112608528A true CN112608528A (en) | 2021-04-06 |
| CN112608528B CN112608528B (en) | 2023-03-14 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1121389A (en) * | 1997-07-02 | 1999-01-26 | Yokohama Rubber Co Ltd:The | Method for bonding galvanized steel cord to rubber and conveyer belt made by using the method |
| JP2010059234A (en) * | 2008-09-01 | 2010-03-18 | Yokohama Rubber Co Ltd:The | Rubber composition for coating steel cord |
| WO2015083746A1 (en) * | 2013-12-03 | 2015-06-11 | バンドー化学株式会社 | Conveyor belt |
| CN104837911A (en) * | 2012-12-14 | 2015-08-12 | 横滨橡胶株式会社 | Rubber composition and conveyor belt |
| WO2017047472A1 (en) * | 2015-09-18 | 2017-03-23 | 横浜ゴム株式会社 | Rubber composition for steel cord covering and tire |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5772227B2 (en) | 2011-05-30 | 2015-09-02 | 横浜ゴム株式会社 | Rubber composition for tire tread for heavy load and pneumatic tire using the same |
-
2019
- 2019-10-03 JP JP2019182769A patent/JP7287232B2/en active Active
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- 2020-09-22 CN CN202011001699.5A patent/CN112608528B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1121389A (en) * | 1997-07-02 | 1999-01-26 | Yokohama Rubber Co Ltd:The | Method for bonding galvanized steel cord to rubber and conveyer belt made by using the method |
| JP2010059234A (en) * | 2008-09-01 | 2010-03-18 | Yokohama Rubber Co Ltd:The | Rubber composition for coating steel cord |
| CN104837911A (en) * | 2012-12-14 | 2015-08-12 | 横滨橡胶株式会社 | Rubber composition and conveyor belt |
| WO2015083746A1 (en) * | 2013-12-03 | 2015-06-11 | バンドー化学株式会社 | Conveyor belt |
| WO2017047472A1 (en) * | 2015-09-18 | 2017-03-23 | 横浜ゴム株式会社 | Rubber composition for steel cord covering and tire |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112608528B (en) | 2023-03-14 |
| JP7287232B2 (en) | 2023-06-06 |
| JP2021059628A (en) | 2021-04-15 |
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