JP2019011197A - Rubber composition for cover rubber layer, and conveyor belt - Google Patents

Abstract

To provide a conveyor belt with suppressed adhesive property with respect to a transportation object.SOLUTION: A conveyor belt comprises a belt body 1 having a three-layered laminate structure in a thickness direction. The belt body 1 is constituted by: a first cover rubber layer 10a constituting an outer peripheral surface on which a transportation object is mounted; a second cover rubber layer 10b constituting an inner peripheral surface; and a core body layer 20 which is formed of canvas and bonded by adhesive rubber between them. The first cover rubber layer 10a and the second cover rubber layer 10b are formed of a cross-linked rubber composition containing adherence inhibitor for inhibiting adhesion of the transportation object.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rubber composition used for forming a cover rubber layer constituting a conveying surface of a conveyor belt, and a conveyor belt provided with a cover rubber layer formed of this rubber composition.

BACKGROUND ART Conventionally, a belt conveyor has been widely used as a conveying device for articles and the like, and various forms of conveyor belts are known as the main constituent members of the belt conveyor.
As this conveyor belt, one in which the belt main body is formed of a rubber composition is widely used. For example, a type of belt in which a core body layer provided with a canvas or a steel cord is sandwiched between two cover rubber layers. Things are widely used.
As the conveyor belt, in addition to a belt main body obtained by processing an endless belt-like belt, a belt provided with a horizontal beam extending in the width direction of the belt main body or a side edge of the belt main body The one having an ear cross provided so as to extend along the surface is widely known.

Such a belt conveyor is normally used for carrying a conveyed product with the conveying surface of the conveyor belt facing upward and rotating the conveyor belt in this state to convey the conveyed product to an unloading place.
The belt conveyor is usually configured to turn the conveyor belt at an unloading place. By this turn, the conveying surface of the conveyor belt is changed from upward to downward to drop a conveyed product loaded on the conveying surface. It is configured to let you.
Thereafter, the conveyor belt is returned to the loading place with the conveyance surface facing downward, and the conveyor belt is turned again so that the conveyance surface is directed upward, and the conveyed product is loaded.

By the way, when the conveyed product conveyed with a belt conveyor is a comparatively fine granular form, there exists a possibility that a conveyed product may be scattered in the middle of conveyance by vibration, the surrounding air current, etc. FIG.
Conventionally, a conveyor belt called a pipe conveyor or the like is known as a conveyor belt used for conveying such a relatively fine granular material (see Patent Document 1 below).
In addition, when the conveyed product has a relatively fine granularity, the conveyed item may adhere to the conveying surface and may fall on the way back to the loading place without dropping at the unloading place.
For this reason, in the above-described pipe conveyor, it is not necessary to make the conveyor belt cylindrical after unloading, but the conveyor belt is also tubular when returning to the loading place to prevent the deposits from falling. It is used in a form that is rounded.

JP 2001-310809 A

From the above, it is desired that the cover rubber layer of the conveyor belt is imparted with an adhesion suppressing effect on the conveyed product.
Such a demand is not only required for a pipe conveyor that conveys a relatively fine granular conveyed product, but is generally required for various conveyor belts.
However, sufficient studies for satisfying this type of request have not been made, and a conveyor belt in which adhesion of conveyed objects is sufficiently suppressed has not been provided.
Then, this invention makes it a subject to satisfy the above problems, and makes it a subject to provide the conveyor belt by which the adhesiveness with respect to a conveyed product was suppressed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has added the above-mentioned request by adding a surfactant or a lubricant to the rubber composition used for forming the cover rubber layer constituting the conveying surface of the conveyor belt. Has been found to be satisfied, and the present invention has been completed.

  That is, the rubber composition for a cover rubber layer of the present invention is used for forming a cover rubber layer that constitutes a conveyance surface of a conveyor belt, and contains an adhesion inhibitor that suppresses adhesion of a conveyance object to the conveyance surface together with rubber. One or more selected from the group consisting of a surfactant and a lubricant is included as the adhesion inhibitor.

  Further, in order to solve the above problems, the present invention is a conveyor belt provided with a cover rubber layer constituting a conveying surface, wherein the cover rubber layer is formed of the rubber composition for a cover rubber layer as described above. Provide a conveyor belt.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition effective in formation of the cover rubber in which adhesion of the conveyed product was suppressed can be provided.

The schematic sectional drawing which showed the structure of the conveyor belt of this embodiment.

The preferred embodiments of the present invention will be described below.
Here, the present invention will be described by taking as an example a conveyor belt which has only a belt main body formed by processing a flat belt-like belt into an endless shape and which is not provided with a cross rail, an ear cross or the like.
FIG. 1 is a diagram showing a conveyor belt according to the present embodiment, and is a diagram schematically showing a cross section of a belt body cut by a virtual plane perpendicular to the longitudinal direction.

As also shown in this figure, the conveyor belt according to the present embodiment includes a belt body having a three-layer laminated structure in the thickness direction.
Specifically, the belt body 1 of the present embodiment has a core body layer 20 interposed between two cover rubber layers 10.
In other words, the belt main body 1 of the present embodiment has the cover rubber layer 10 laminated on both the front and back surfaces of the core body layer 20.
The belt main body 1 of the conveyor belt in the present embodiment includes a first cover rubber layer 10a that constitutes an outer peripheral surface (hereinafter also referred to as “conveying surface” or “surface”) on which a conveyed product is placed, and an inner peripheral surface. The core body layer 20 between the two cover rubber layers and the second cover rubber layer 10b constituting the “opposite surface opposite to the conveyance surface” or “back surface” is composed of canvas.
In the present embodiment, the canvas and the cover rubber layer are bonded with an adhesive rubber (not shown).

In the present embodiment, the first cover rubber layer 10a and the second cover rubber layer 10b of the conveyor belt are formed of a rubber elastic body that is excellent in prevention of adhesion of a conveyed product.
The rubber elastic body in the present embodiment is made of a crosslinked rubber composition.
A rubber composition for a cover rubber layer that forms the cover rubber layer (hereinafter, also simply referred to as “rubber composition”) includes rubber and an adhesion inhibitor.
This adhesion inhibitor is for suppressing adhesion of the conveyed product with respect to a conveyance surface.
Whether or not it can be used as the above-mentioned adhesion inhibitor by exhibiting the effect of suppressing the adhesion of the conveyed product to the conveyance surface is specifically described as a “method for“ verification of adhesion suppression effect ”” in the subsequent examples. It can be confirmed by the method shown automatically.
That is, "verification of adhesion suppression effect" is performed with a rubber composition having a common blending content other than the presence or absence of an adhesion inhibitor, and the adhesion inhibitor is a predetermined amount or more (for example, 10 parts by mass or more with respect to 100 parts by mass of rubber). If a significant difference is found between the verification result blended at a ratio of 1 and the verification result when the adhesion inhibitor is not contained, it can be determined that the adhesion inhibitor functions effectively.

The rubber composition of this embodiment contains one or more compounds selected from the group consisting of a surfactant and a lubricant as the adhesion inhibitor.
The rubber composition of this embodiment further contains a filler, a crosslinking agent, an additive, and the like.

The rubber composition of this embodiment contains a diene rubber and a thermoplastic elastomer as the rubber.
Examples of the diene rubber contained in the rubber composition of the present embodiment include natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, and chloroprene rubber.
Among these, the rubber composition of the present embodiment preferably contains natural rubber and butadiene rubber.
In the rubber composition of the present embodiment, only one type may be selected and contained from a plurality of types of commercially available natural rubbers, or a plurality of types may be blended and contained.
The same applies to butadiene rubber. Either one of a plurality of commercially available butadiene rubbers may be selected and included in the rubber composition, or a plurality of types may be blended and included in the rubber composition. Good.

The mass proportion of natural rubber in all rubbers contained in the rubber composition is preferably 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more.
The mass proportion of natural rubber in all the rubbers contained in the rubber composition is preferably 95% by mass or less, more preferably 85% by mass or less, and particularly preferably 75% by mass or less.

The mass proportion of butadiene rubber in all the rubbers contained in the rubber composition is preferably 20% by mass or more, more preferably 25% by mass or more, and particularly preferably 30% by mass or more.
The mass proportion of butadiene rubber in all the rubbers contained in the rubber composition is preferably 55% by mass or less, more preferably 50% by mass or less, and particularly preferably 45% by mass or less.

When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of other rubbers is preferably less than 15 parts by mass, and less than 12.5 parts by mass. More preferably, it is less than 10 parts by mass.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of other rubbers is preferably more than 0 parts by mass and more than 1 part by mass. Preferably, it exceeds 2 mass parts, and it is especially preferable.

In addition to natural rubber and butadiene rubber, examples of suitable rubber to be included in the rubber composition include the thermoplastic elastomer.
The thermoplastic elastomer can be, for example, a polyolefin-based thermoplastic elastomer (TPO), a styrene-based thermoplastic elastomer (TPS), a polyurethane-based thermoplastic elastomer (TPU), or a polyamide-based thermoplastic elastomer (TPA).

The thermoplastic elastomer is preferably a block copolymer having a plurality of low-polarity low-polar blocks, for example.
Examples of the monomer that is a constituent unit of the low polarity block include α-olefins having 2 or more carbon atoms.
Examples of the monomer include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1- Examples include octene.
One low polarity block among the plurality of low polarity blocks constituting the thermoplastic elastomer is preferably composed of ethylene, and the other low polarity block among the plurality of low polarity blocks is α- It is preferably composed of olefin.
The thermoplastic elastomer is preferably an ethylene / α-olefin block copolymer.
The α-olefin constituting the thermoplastic elastomer is preferably 1-octene.
That is, the thermoplastic elastomer is preferably an ethylene / 1-octene block copolymer.

When the total amount of the natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the first thermoplastic elastomer is preferably 0.5 parts by mass or more, preferably 1 mass. More preferably, it is more preferably 2 parts by mass or more.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the first thermoplastic elastomer is preferably 6 parts by mass or less, and preferably 5 parts by mass or less. It is more preferable that

The thermoplastic elastomer contained in the rubber composition may include a repeating unit having a polar group in order to improve the affinity between the surfactant or the lubricant and the diene rubber.
The thermoplastic elastomer may be, for example, a block copolymer having a high polarity block such as a polyacrylate block and a low polarity block having a lower polarity than the high polarity block.
Examples of the monomer that is a constituent unit of the low polarity block include α-olefins having 2 or more carbon atoms.
Examples of the monomer include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1- Examples include octene.
The monomer that is a constituent unit of the highly polar block is formed from, for example, an unsaturated acid such as acrylic acid or methacrylic acid; acrylic acid such as methyl acrylate or ethyl acrylate, and an alkyl alcohol having 1 to 10 carbon atoms. Acrylic acid esters; methacrylic acid esters formed from methacrylic acid such as methyl methacrylate and ethyl methacrylate and alkyl alcohols having 1 to 10 carbon atoms; vinyl cyanide such as acrylonitrile and methacrylonitrile; vinyl acetate and propionic acid Vinyl esters such as vinyl; acrylic esters formed from acrylic acid such as polyethylene glycol acrylate and polytetramethylene glycol acrylate and long chain glycols having a molecular weight of 80 to 6000; polyethylene glycol methacrylate, poly methacrylate Methacrylic acid ester formed from methacrylic acid such as tramethylene glycol and long chain glycol having a molecular weight of 80 to 6000; Unsaturated epoxy compound such as glycidyl methacrylate; 3-hydroxy-1-propene, 4-hydroxy-1-butene , A compound having a hydroxyl group such as cis-1,4-dihydroxy-2-butene, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl crotonic acid; Examples thereof include fumaric acid, maleic anhydride, maleimide and the like.

When the thermoplastic elastomer contains a low polarity block and a high polarity block, the thermoplastic elastomer has a mass ratio of the low polarity block of 55% by mass to 95% by mass (the high polarity block is 5% by mass to 45% by mass). % Or less).
The rubber composition of this embodiment does not need to contain a single thermoplastic elastomer, and may contain a plurality of types of thermoplastic elastomers.

  Examples of the surfactant contained in the rubber composition as the adhesion inhibitor include anionic surfactants, cationic surfactants, nonionic surfactants, and zwitterionic surfactants.

  Examples of the anionic surfactant include fatty acid sodium, fatty acid potassium, sodium alkylbenzene sulfonate, sodium alkyl sulfate ester, sodium alkyl sulfonate, sodium alkyl ether sulfate, monoalkyl phosphate ester, polyoxyethylene alkyl ether phosphate. Examples include sodium acid ester, sodium fatty acid ester sulfonate, sodium fatty acid ester sulfate, sodium fatty acid alkylose amide sulfate, sodium fatty acid amide sulfonate, and the like.

  Examples of the cationic surfactant include alkylmethylammonium chloride, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, alkyldimethylbenzylammonium chloride, and alkylpyridinium chloride.

  Examples of the nonionic surfactant include sucrose fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene lanolin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycol monofatty acid ester, isopropanolamide, alkylamine oxide, polyoxyethylene Examples thereof include oxyethylene amine, polyoxyethylene alkyl ether, and polyoxyethylene alkyl phenyl ether.

  Examples of the zwitterionic surfactant include carboxybetaine, alkylbetaine, sulfobetaine, and phosphobetaine.

  When the rubber composition of the present embodiment contains a surfactant, the surfactant does not need to be contained alone, and a plurality of types may be contained.

  Examples of the lubricant contained in the rubber composition as the adhesion inhibitor include fatty acid salts and fatty acid amides.

Examples of the fatty acid salts include metal salts such as saturated fatty acids such as lauric acid, palmitic acid, stearic acid, and behemic acid; unsaturated fatty acids such as erucic acid, oleic acid, brassic acid, and elaidic acid. A magnesium salt, a calcium salt, a sodium salt, a potassium salt, etc. are mentioned.
Examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behemic acid amide, erucic acid amide, oleic acid amide, brassic acid amide, elaidic acid amide, methylene bis stearic acid amide, and methylene bis oleic acid. Examples thereof include amide, ethylene bis stearic acid amide, and ethylene bis oleic acid amide.

  When a lubricant is contained in the rubber composition of this embodiment, the lubricant does not need to be contained alone, and a plurality of kinds may be contained.

As the lubricant, a fatty acid amide is suitable.
10-25 are preferable and, as for carbon number of fatty acid amide, 12-22 are more preferable.
The melting point of the fatty acid amide is preferably 40 ° C. or higher and 110 ° C. or lower, more preferably 60 ° C. or higher and 95 ° C. or lower.

The melting point of the fatty acid amide can be measured by a so-called transparent method using a capillary tube.
Specifically, the melting point of the fatty acid amide is determined according to a test method based on “7.5.2 Visual method” in JIS K6220-1: 2015 “Rubber compounding agent—Organic chemicals—Test method—Part 1: General”. Can be measured.

The fatty acid amide used as the lubricant can form a chemical bond with the diene rubber when the rubber composition is crosslinked by having an unsaturated bond, and is lost from the cover rubber layer by bleed-out. It can be suppressed.
The fatty acid amide preferably has an iodine value of 70 or more.
The iodine value of the fatty acid amide is more preferably 72 or more.
The iodine value of the fatty acid amide is preferably 90 or less, more preferably 85 or less, and particularly preferably 80 or less.
The fatty acid amide used as a lubricant in this embodiment is preferably erucic acid amide.

  The iodine value of a fatty acid amide should be measured based on the method described in JIS K0070: 1992 “Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponified product of chemical products”. Can do.

When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the lubricant is preferably 0.5 parts by mass or more, and preferably 1 part by mass or more. Is more preferable, and 2 parts by mass or more is particularly preferable.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the lubricant is preferably 10 parts by mass or less, more preferably 8 parts by mass or less. It is preferably 5 parts by mass or less.

  It is preferable that the rubber of the rubber composition in the present embodiment further contains fats and oils as the adhesion inhibitor.

Examples of fats and oils include fatty acids and fatty acid esters in which a carboxyl group is bonded to the terminal of a hydrocarbon chain having 6 to 18 carbon atoms (carbon bonded with hydrogen bonded in a chain).
Examples of the oils and fats include vegetable oils such as soybean oil, rapeseed oil, palm oil and palm oil; animal oils such as beef tallow, lard and liver oil; and mineral oils such as paraffinic mineral oil.

  When fats and oils are contained in the rubber composition of the present embodiment, the fats and oils do not need to be contained singly, and plural kinds of fats and oils may be contained.

The surfactant, the lubricant, and the oil / fat bleed out on the surface of the cover rubber to suppress adhesion of the conveyed product.
And the said thermoplastic elastomer exhibits the function to make this bleed out slow.
Among these, the thermoplastic elastomer is effective for release of the lubricant.
Therefore, the rubber composition of this embodiment preferably contains the lubricant as the adhesion inhibitor, and the rubber further contains a thermoplastic elastomer together with the diene rubber.

When the lubricant or the fat / oil has an unsaturated bond, it may have a high molecular weight by ultraviolet rays or the like after bleeding out on the conveying surface to generate an adhesive compound.
Therefore, it is preferable that the lubricant and the oil or fat have a low unsaturated bond or become a dry state when a film is formed quickly when the unsaturated bond is exposed to sunlight at a certain level or more.
Accordingly, the lubricant and the oil / fat have an element value of 100 or less as determined by JIS K0070-1992 “Testing method for acid value, saponification value, ester value, iodine value, hydroxyl value, and unsaponified product of chemical products”. Or an iodine value of 90 or less or 150 or more.

In the present embodiment, the rubber composition preferably contains a plurality of adhesion inhibitors.
The rubber composition of the present embodiment preferably contains the surfactant as the adhesion inhibitor and further contains fats and oils as the adhesion inhibitor.
The rubber composition of the present embodiment preferably contains both the surfactant and the lubricant as the adhesion inhibitor.

These adhesion inhibitors are preferably contained in the rubber composition at a predetermined ratio with respect to the diene rubber.
The total content of the adhesion inhibitor is preferably 1 part by mass or more and 35 parts by mass or less, more preferably 5 parts by mass or more and 20 parts by mass or less, with respect to 100 parts by mass of the diene rubber. More preferably, it is 17 parts by mass or less.

The rubber composition of the present embodiment preferably further contains a compatibilizer in order to suppress excessive bleeding out of the adhesion inhibitor on the surface of the cover rubber.
The compatibilizer is preferably a thermoplastic resin, and is preferably a block copolymer having a low polarity block and a high polarity block.
The low polarity block in the block copolymer used as the compatibilizer is preferably composed of ethylene.
The highly polar block of the block copolymer is preferably composed of acrylic acid.
That is, the rubber composition of this embodiment preferably contains an ethylene / ethyl acrylate block copolymer (EEA) as the compatibilizing agent.

The rubber composition of the present embodiment preferably further contains a compatibilizing agent different from the ethylene / ethyl acrylate block copolymer.
That is, the rubber composition of the present embodiment contains a first compatibilizing agent that is an ethylene / ethyl acrylate block copolymer and a second compatibilizing agent different from the first compatibilizing agent. Is preferred.

The second compatibilizer is preferably a graft copolymer obtained by grafting another block copolymer to the same or different ethylene / ethyl acrylate block copolymer as the first compatibilizer. .
That is, the second compatibilizing agent is preferably a graft copolymer in which an ethylene / ethyl acrylate block copolymer constitutes the main chain and has a side chain composed of the other block copolymer.
The block copolymer constituting the side chain of the graft copolymer is preferably an n-butyl acrylate / 2-hydroxypropyl acrylate / styrene terpolymer.

When the total amount of the natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the first compatibilizer is preferably 0.5 parts by mass or more, and 1 part by mass. More preferably, it is more preferably 2 parts by mass or more.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the first compatibilizer is preferably 10 parts by mass or less, and 8 parts by mass or less. It is more preferable that

When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the second compatibilizing agent is preferably 0.5 parts by mass or more, preferably 1 part by mass. More preferably, it is more preferably 2 parts by mass or more.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the content of the second compatibilizer is preferably 6 parts by mass or less, and preferably 5 parts by mass or less. It is more preferable that

When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the total content of all compatibilizers is preferably 1 part by mass or more, preferably 2 parts by mass or more. More preferably, it is more preferably 4 parts by mass or more.
When the total amount of natural rubber and butadiene rubber contained in the rubber composition is 100 parts by mass, the total content of all compatibilizers is preferably 16 parts by mass or less, and 15 parts by mass or less. More preferably, it is particularly preferably 14 parts by mass or less.

The rubber composition of this embodiment further contains a filler, a crosslinking agent, and an additive as described above.
Examples of the filler include carbon black, silica, calcium carbonate, talc, clay, aluminum hydroxide, and magnesium hydroxide.
The rubber composition of this embodiment does not need to contain one type of filler alone, and may contain a plurality of types of fillers.

Among those exemplified above, carbon black is preferably contained in the rubber composition because it is particularly excellent in the reinforcing effect of rubber.
The rubber composition of the present embodiment preferably contains 20 to 100 parts by mass of carbon black with respect to 100 parts by mass of the diene rubber, and contains 30 to 90 parts by mass of carbon black. More preferably.

Examples of the crosslinking agent contained in the rubber composition include sulfur and organic peroxides.
As a crosslinking agent contained in the rubber composition of this embodiment, sulfur is preferable.
Further, the rubber composition may further contain a vulcanization accelerator such as N-cyclohexyl-2-benzothiazolylsulfenamide, a vulcanization acceleration assistant such as zinc oxide, and the like.

Examples of the additive include functional agents such as anti-aging agents such as amine-ketone compounds, aromatic secondary amine compounds, benzimidazole compounds, and special waxes; flame retardants; weathering agents; .
Examples of the additive include processability improvers such as process oil, peptizer, and scorch inhibitor.

The conveyor belt may use a common rubber composition for forming the first cover rubber layer 10a and the second cover rubber layer 10b, and each may be formed of a different rubber composition. It may be.
Further, the first cover rubber layer 10a and the second cover rubber layer 10b may have different thicknesses or the like.
In particular, the conveyor belt preferably has a thickness of the first cover rubber layer that is greater than a thickness of the second cover rubber layer.
For example, the thickness of the first cover rubber layer 10a constituting the transport surface is preferably 1.1 times or more the thickness of the second cover rubber layer 10b constituting the opposite surface of the transport surface. It is more preferably 5 times or more, and particularly preferably 2 times or more.
The thickness of the first cover rubber layer 10a is usually 5 mm or more and 15 mm or less, and the thickness of the second cover rubber layer 10b is usually 1 mm or more and less than 5 mm.

The canvas for forming the core layer 20 is not particularly limited, and a canvas used for a general conveyor belt can be used in this embodiment.
Further, the core layer 20 may be formed using a steel cord or the like instead of the canvas.

  Furthermore, the adhesive rubber is not particularly limited, and those used in general conveyor belts can be employed in this embodiment.

The manufacturing method of the conveyor belt of this embodiment is not particularly limited, and can be manufactured in the same manner as a general conveyor belt.
The conveyor belt is, for example, a kneaded rubber composition for a cover rubber layer using a Banbury mixer, a kneader mixer, an open roll, and the like, and then the rubber composition is formed into a sheet using a calendar or the like to form a cover rubber layer The unvulcanized sheet can be produced, and the canvas carrying the surface of the adhesive rubber and the unvulcanized sheet can be integrated by vulcanization.

In the present embodiment, it is not necessary to use the rubber composition for the cover rubber layer only for the cover rubber layer, and it may be used for forming adhesive rubber, ear rubber or the like.
Further, in the present embodiment, an example in which cover rubber layers are provided on both surfaces of the core body layer is illustrated, but the cover rubber layer formed of the rubber composition for the cover rubber layer of the present embodiment is at least the core. What is necessary is just to be provided in the single side | surface (conveyance surface side) of the body layer.
In this embodiment, a conveyor belt having only a flat belt-like belt body is illustrated, but a three-dimensional shape is imparted to the belt body itself by being produced using a hot press having unevenness on the press surface. Conveyor belts of the type of the present invention are also intended as conveyor belts of the present invention, and conveyor belts of a type in which a horizontal beam and an ear beam are attached as separate parts to a flat belt-like belt body.
And in the conveyor belt which has a horizontal crosspiece or an ear crosspiece, the rubber composition for conveyor belts can also be used for formation of this horizontal crosspiece or an ear crosspiece.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(Materials used)
Table 1 below shows the abbreviations and specific contents of the compounding agents used for the addition of the adhesion inhibitor.

上記のような原料を表３に示す配合割合で含有するゴム組成物を用いて加硫ゴムシートを作製し、該加硫ゴムシートによって各評価を実施した。
Table 2 below shows the abbreviations of anti-aging agents and their specific contents.

A vulcanized rubber sheet was prepared using a rubber composition containing the raw materials as described above at a blending ratio shown in Table 3, and each evaluation was performed using the vulcanized rubber sheet.

In addition, specifically, “oil sulfur” was used as sulfur in the above blending.
Moreover, N-cyclohexyl-2-benzothiazolylsulfenamide was used as a vulcanization accelerator.

(Evaluation 1: Verification of adhesion suppression effect)
A rubber sheet for evaluation (crosslinked rubber sheet) was prepared with the blending contents shown in each Example and Table 3, and the adhesion of the conveyed product was evaluated by the following procedures 1) to 5).

1) A fine granular coal adjusted to a predetermined moisture content is put into a plastic container.
2) Put a test piece cut out from a rubber sheet into a predetermined shape in the same plastic container.
3) Set a plastic container on the rotary stirrer and stir the contents (coal, test piece).
4) Take out the test piece and collect the coal adhering to the surface on one side.
5) Measure the mass of the collected coal.

In addition, an adhesion test using fine granular iron ore (iron ore adjusted to a particle size of 2 mm or less by classification) was performed in the same manner as in the above procedures 1) to 5).
Furthermore, the adhesion test using a true sand soil was implemented like the procedure of said 1) -5).
The results are also shown in Table 3.

  From the above results, it can be seen that according to the present invention, an excellent adhesion suppressing effect can be exerted on the conveyor belt.

  1: belt body (conveyor belt), 10: cover rubber layer (10a: first cover rubber layer, 10b: second cover rubber layer), 20: core body layer

Claims (6)

Used to form a cover rubber layer that constitutes the conveyor belt transport surface,
Containing an adhesion inhibitor that suppresses adhesion of the conveyed product to the conveying surface together with rubber;
A rubber composition for a cover rubber layer, wherein at least one selected from the group consisting of a surfactant and a lubricant is contained as the adhesion inhibitor.   The rubber composition for a cover rubber layer according to claim 1, comprising the surfactant as the adhesion inhibitor, and further containing fats and oils as the adhesion inhibitor.   The rubber composition for a cover rubber layer according to claim 1, comprising the lubricant as the adhesion inhibitor, and a thermoplastic elastomer together with a diene rubber as the rubber.   The rubber composition for a cover rubber layer according to any one of claims 1 to 3, comprising both the surfactant and the lubricant as the adhesion inhibitor. A conveyor belt provided with a cover rubber layer constituting a conveying surface,
The conveyor belt in which the said cover rubber layer is formed with the rubber composition for cover rubber layers of any one of Claims 1 thru | or 4. A first cover rubber layer constituting the conveying surface;
A second cover rubber layer constituting the opposite surface of the conveying surface,
The conveyor belt according to claim 5, wherein a thickness of the first cover rubber layer is thicker than a thickness of the second cover rubber layer.

Images