JP5440048B2 - Conveyor belt - Google Patents

Description

  The present invention relates to a conveyor belt using an aramid canvas as a core material. More specifically, the present invention provides excellent adhesion between the core aramid canvas and rubber, provides good durability, and forms an adhesive rubber layer. The present invention relates to a conveyor belt that is excellent in treating workability and laminating workability of a rubber composition and excellent in productivity.

  Steel cords are widely used as a reinforcing material for rubber products such as conveyor belts. At that time, the adhesion between the rubber composition and the steel cord greatly affects the durability of the products.

  Conventionally, as a measure for satisfactorily adhering a steel cord and rubber, a method of combining rosin, organic acid cobalt salt and organic chlorine compound into rubber (Patent Document 1: Japanese Patent Laid-Open No. 2006-31744), triazine , Zinc dimethacrylate, zinc diacrylate and organic acid cobalt in combination with rubber (Patent Document 2: JP-A-2005-350491), acid-modified polymer and zinc dimethacrylate in combination A method of blending with a rubber component (Patent Document 3: Japanese Patent Laid-Open No. 2006-176580) has been proposed.

  On the other hand, since the aramid fiber has high strength, it can be replied compared to nylon and PET, which are widely used as a reinforcing layer, and therefore, aramid canvas is also used as a core material for conveyor belts. In the above-described conventional technology, a sufficient adhesive force is not necessarily obtained for an aramid canvas.

  In addition, when manufacturing a conveyor belt using aramid canvas as a core material, a treating operation is required in which rubber rolled with a roll or the like is bonded to the canvas, and this treating workability, laminating workability, and vulcanization speed are also included in the conveyor. It greatly affects the productivity of the belt, and good treatability, lamination processability, and vulcanization speed are important performances for the rubber composition for the conveyor belt.

JP 2006-31744 A JP 2005-350491 A JP 2006-176580 A

  The present invention has been made in view of the above circumstances, and using an aramid canvas as a core material, the aramid canvas and rubber can be bonded well to achieve excellent durability, and the aramid canvas and cover rubber can be achieved. An object of the present invention is to provide a conveyor belt in which a rubber composition for forming an adhesive rubber layer that adheres to each other has good treatability, lamination workability, vulcanization speed, and excellent productivity.

  As a result of intensive studies to solve the above problems, the present inventor has found that the rubber composition of the adhesive rubber layer includes zinc dimethacrylate and organic acid cobalt in order to improve the adhesion between the adhesive rubber layer and the aramid canvas. When adding and blending, together with a cobalt neodecanoate compound and cobalt stearate as the organic acid cobalt, by adjusting the blending ratio, it is possible to improve the adhesion with the aramid canvas, and good The present invention has been completed by finding that a conveyor belt having excellent treatability, laminating workability, and vulcanization speed and excellent durability can be obtained with high productivity.

Therefore,
(1) The present invention provides a conveyor belt in which an aramid canvas covered with an adhesive rubber layer is disposed as a core between cover rubber layers, and the adhesive rubber layer is dimethacrylic with respect to 100 parts by mass of the rubber component. Conveyor belt formed of a rubber composition containing 0.5 to 3 parts by mass of zinc oxide, 1 to 10 parts by mass of cobalt neodecanoate compound, and 0.5 to 4 parts by mass of cobalt stearate. I will provide a.

  Further, as a result of further investigations, the present inventor has found that a mixed rubber obtained by mixing natural rubber and synthetic rubber such as styrene-butadiene rubber (SBR) at a predetermined ratio is preferable as the rubber component, and cobalt neodecanoate. As the compound, it is preferable to use either one or both of cobalt neodecanoate and cobalt neodecanoate borate, phenol resin, particularly phenol resin internally added with hexamethylenetetramine, β-naphthol, hexamethoxymethylated melamine ( It has been found that the adhesiveness can be further improved by adding a predetermined amount of a curing agent.

Therefore, the present invention provides the following (2) to (8) as preferred embodiments.
(2) The conveyor belt according to (1), wherein the rubber composition contains one or both of cobalt neodecanoate and cobalt neodecanoate borate as the cobalt neodecanoate compound.
(3) The conveyor belt according to (1) or (2), wherein 20 to 70 parts by mass of natural rubber and 80 to 30 parts by mass of synthetic rubber are contained in 100 parts by mass of the rubber component of the rubber composition.
(4) The conveyor belt according to (3), wherein the synthetic rubber is one or more selected from styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR).
(5) The conveyor belt according to any one of (1) to (4), wherein the rubber composition contains 1 to 10 parts by mass of a phenol resin with respect to 100 parts by mass of the rubber component.
(6) The conveyor belt according to (5), wherein the phenol resin is a resin in which hexamethylenetetramine is internally added.
(7) The conveyor belt according to any one of (1) to (6), wherein the rubber composition contains 1 to 10 parts by mass of β-naphthol with respect to 100 parts by mass of the rubber component.
(8) Any of (1) to (7), wherein the rubber composition contains 1 to 10 parts by mass of hexamethoxymethylated melamine and / or hexamethylenetetramine as a curing agent with respect to 100 parts by mass of the rubber component. Conveyor belt.

  The conveyor belt of the present invention has excellent adhesion between the aramid canvas of the core material and rubber, has good durability, and the rubber composition forming the adhesive rubber layer has good treat workability, lamination processability, It has a vulcanization rate and excellent productivity.

It is a schematic sectional drawing which shows the test piece used for the adhesiveness test in an Example.

  As described above, the conveyor belt of the present invention is a conveyor belt in which an aramid canvas covered with an adhesive rubber layer is disposed as a core between cover rubber layers, and the rubber composition forming the adhesive rubber layer includes , 0.5 to 3 parts by mass of zinc dimethacrylate, 1 to 10 parts by mass of cobalt neodecanoate compound, and 0.5 to 4 parts by mass of cobalt stearate with respect to 100 parts by mass of the rubber component. .

  As the rubber component of the rubber composition forming the adhesive rubber layer, a known rubber can be used as the core adhesive rubber layer in the conveyor belt. For example, natural rubber or a mixture of natural rubber and synthetic rubber is used. be able to.

  In this case, as the synthetic rubber, polyisoprene rubber (IR), polybutadiene rubber (BR), polychloroprene rubber and the like, which are homopolymers of conjugated diene compounds such as isoprene, butadiene, and chloroprene, the conjugated diene compound and styrene, Styrene butadiene copolymer rubber (SBR), vinyl pyridine butadiene styrene copolymer rubber, acrylonitrile butadiene copolymer, which are copolymers with vinyl compounds such as acrylonitrile, vinyl pyridine, acrylic acid, methacrylic acid, alkyl acrylates, alkyl methacrylates, etc. Rubber, butadiene acrylate copolymer rubber, butadiene copolymer methacrylate rubber, methyl acrylate butadiene copolymer rubber, methyl methacrylate butadiene copolymer rubber, ethylene, propylene, isobutyl Copolymers of olefins such as ethylene and diene compounds [eg, isobutylene isoprene copolymer rubber (IIR)], copolymers of olefins and non-conjugated dienes (EPDM) [eg, ethylene-propylene-cyclopentadiene ternary copolymer Polymers, ethylene-propylene-5-ethylidene-2-norbornene terpolymers, ethylene-propylene-1,4-hexadiene terpolymers], polyalkenamers obtained by ring-opening polymerization of cycloolefins (for example, Polypentenamer], rubber obtained by ring-opening polymerization of an oxirane ring (for example, polyepichlorohydrin rubber capable of sulfur vulcanization), polypropylene oxide rubber and the like. Further, halides of the above various rubbers such as chlorinated isobutylene isoprene copolymer rubber (Cl-IIR), brominated isobutylene isoprene copolymer rubber (Br-IIR) and the like are also included. Further, a ring-opening polymer of norbornene can be used. Furthermore, a saturated elastic body such as epichlorohydrin rubber, polypropylene oxide rubber, or chlorosulfonated polyethylene can be blended with the above-mentioned rubber. As the synthetic rubber, styrene butadiene copolymer rubber (SBR) is preferably used.

  The blending ratio of the natural rubber and the synthetic rubber is not particularly limited, but usually 20 to 70 parts by mass of natural rubber, 80 to 30 parts by mass of synthetic rubber, particularly natural rubber 20 in 100 parts by mass of the rubber component. It is preferable to set it as -50 mass parts and synthetic rubber 80-50 mass parts.

  In the rubber composition of the adhesive rubber layer used in the present invention, 0.5 to 3 parts by mass, preferably 0.5 to 2 parts by mass of zinc dimethacrylate is added to 100 parts by mass of the rubber component. If the blending amount is less than 0.5 parts by mass, sufficient adhesion to the aramid canvas cannot be obtained, and the object of the present invention cannot be achieved. In addition, the roll workability is greatly lowered and the productivity is lowered, so that the object of the present invention cannot be achieved.

  Further, in the present invention, the zinc dimethacrylate and cobalt neodecanoate are used in combination, thereby improving the adhesive force with the aramid canvas more effectively. Although it does not restrict | limit especially as this neodecanoic acid cobalt compound, Neodecanoic acid cobalt or neodecanoic acid cobalt borate is used preferably, and these can also be used together. In this case, addition of cobalt neodecanoate borate can improve the vulcanization rate of the rubber composition together with the adhesiveness.

  The compounding amount of the cobalt neodecanoate compound is 1 to 10 parts by mass with respect to 100 parts by mass of the rubber component, and in particular, when cobalt neodecanoate is used, 2 to 6 parts by mass with respect to 100 parts by mass of the rubber component and In addition, when using cobalt decanoate of neodecanoate, the amount is preferably 1.5 to 3.5 parts by mass with respect to 100 parts by mass of the rubber component. It is preferable to set it as 1.5-5 mass parts with respect to 100 mass parts of components. If the addition amount of the neodecanoic acid cobalt compound is less than 1 part by mass, sufficient adhesion performance cannot be obtained. On the other hand, if it exceeds 10 parts by mass, heat aging, reduced water-resistant adhesion, high cost, roll Inconveniences such as a decrease in workability may occur, and neither is preferable.

  Next, in the present invention, cobalt stearate is blended together with the cobalt neodecanoate compound. Thereby, the adhesiveness of a composition can be adjusted appropriately, and treat workability and roll workability can be improved without reducing lamination workability. In this case, the compounding quantity of cobalt stearate shall be 0.5-3 mass parts with respect to 100 mass parts of said rubber components, Preferably it is 0.5-2 mass parts. If the blending amount is less than 0.5 parts by mass, the treatment efficiency and roll workability improvement effect due to the addition may not be sufficiently obtained. On the other hand, if it exceeds 3 parts by mass, the adhesiveness may be lowered, or the cover In some cases, the rubber tackiness in the rubber lamination process is lowered, and the laminating workability is lowered. The term “roll processability” as used herein refers to the processability when kneading the rubber composition and passing it through a rolling roll to form a belt-like rubber having a predetermined thickness and width.

  In the rubber composition used as the adhesive rubber layer in the present invention, an appropriate amount of a phenol resin can be blended for the purpose of further improving the adhesiveness. In this case, the phenol resin includes phenol-formaldehyde resin, resorcin-formaldehyde resin, cresol-formaldehyde resin and the like, and phenol-formaldehyde resin is particularly preferably used. In addition to 100% phenol resin, natural resin-modified phenol resin, oil-modified phenol resin, and the like can be used as the phenol resin. Here, although not particularly limited, those internally added with hexamethylenetetramine (hexamine), hexamethoxymethylated melamine (HMMM) and the like are preferably used because they further improve the adhesiveness. Phenol resins into which hexamethylenetetramine is added internally are preferably used.

  The blending amount of these phenol resins is not particularly limited, but is preferably 1 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component. In this case, if the blending amount is less than 1 part by mass, a sufficient effect due to the addition may not be obtained. In some cases, it is not preferable from the viewpoint of decrease in performance and cost. In addition, this phenol resin can also use 2 or more types together.

  In addition, for the purpose of further improving the adhesive force, a monocyclic aromatic compound containing a hydroxyl group such as resorcin and a polycyclic aromatic compound containing a hydroxyl group such as β-naphthol can be blended, In particular, β-naphthol is preferably used. The blending amount of β-naphthol and resorcin is not particularly limited, but is 1 to 10 parts by mass, particularly 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component. If the blending amount is less than 1 part by mass, a sufficient effect due to the addition may not be obtained. On the other hand, if it exceeds 10 parts by mass, the physical properties of the rubber may be deteriorated or economically undesirable. Note that β-naphthol is preferably used in combination with hexamethoxymethylated melamine and / or hexamethylenetetramine, which will be described later.

  Furthermore, a hardening | curing agent can be mix | blended for the purpose of the improvement of adhesive force. Examples of the curing agent include methylene donors, and hexamethylenetetramine and methylolated melamine derivatives are preferably used. Examples of methylolated melamine derivatives include hexamethylolated melamine, hexamethoxymethylated melamine, and hexaethoxymethylated. Melamine, N, N ′, N ″ -trimethyl-N, N ′, N ″ -trimethylolated melamine, N, N ′, N ″ -trimethylolated melamine, N-methylolated melamine, N, N′-di (Methoxymethyl) melamine, N, N ′, N ″ -tributyl-N, N ′, N ″ -trimethylolated melamine and the like. Among these, hexamethoxymethylated melamine and / or hexamethylenetetramine are particularly preferable. The hexamethoxymethylated melamine and this are preferably used. / Or hexamethylenetetramine is preferably used in combination with the β- naphthol.

  Although the compounding quantity of a hardening | curing agent is not restrict | limited in particular, It is preferable to set it as 1-10 mass parts with respect to 100 mass parts of rubber components, especially 1-7 mass parts. If the blending amount is less than 1 part by mass, the effect due to the addition may not be sufficiently obtained. On the other hand, if it exceeds 10 parts by mass, the physical properties of the rubber may be deteriorated or economically undesirable.

  In this rubber composition, sulfur, an organic sulfur compound, and other vulcanizing agents are usually used, and are not particularly limited, but usually 1 to 10 parts by mass with respect to 100 parts by mass of the rubber component, Preferably, 2 to 5 parts by mass of a vulcanizing agent is blended. Although not particularly limited, vulcanization accelerating aids such as zinc white and stearic acid are added together with these vulcanizing agents in an amount of 1 to 20 parts by mass, preferably 3 to 15 parts per 100 parts by mass of the rubber component. A mass part can be mix | blended.

  Further, the rubber composition includes, for example, paraffinic, naphthenic, aromatic process oil, ethylene-α-olefin co-oligomer, paraffin wax, liquid paraffin and other mineral oil, castor oil, cottonseed oil, linseed oil, Oils such as rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil and other vegetable oils can also be blended, and aromatic process oils (aromatic oils) are particularly preferably used. Although the compounding quantity is not specifically limited, 1-10 mass parts with respect to 100 mass parts of rubber components, Preferably 2-7 mass parts can be mix | blended. Furthermore, a rubber composition can be prepared by adding an appropriate amount of fillers such as carbon black, silica, calcium carbonate, calcium sulfate, clay and mica according to the purpose and application, and carbon black is particularly preferably used.

  In addition, various rubber additives can be blended with the rubber composition as needed within a range that does not impair the object of the present invention. For example, vulcanization accelerators such as sulfenamides, anti-aging agents, waxes, antioxidants, foaming agents, plasticizers, lubricants, tackifiers, ultraviolet absorbers and the like can be appropriately contained.

  This rubber composition can be placed on and closely adhered to the aramid canvas and vulcanized so that it can adhere well to the aramid canvas. For example, the aramid canvas is sandwiched with a sheet of this rubber composition, and the rubber composition is heated. The core of the conveyor belt of the present invention can be formed by adhering and covering the rubber composition to the aramid canvas by pressure bonding and vulcanization adhesion. In this case, the vulcanization conditions are appropriately selected according to the type of the vulcanizing agent and the vulcanization accelerator. For example, in the case of sulfur vulcanization, the conditions can be set at 135 to 180 ° C. for 10 to 100 minutes.

  In the conveyor belt of the present invention, a core body coated with a galvanized steel cord with an adhesive rubber layer made of the above rubber composition is disposed and bonded between cover rubber layers. In this case, the rubber composition and the like of the aramid canvas and the cover rubber layer can be appropriately selected according to the use of the conveyor belt and the like, and known ones can be used.

  For example, the aramid canvas is not particularly limited, but an epoxy resin layer is formed on the surface of an aromatic aramid fiber body, and the epoxy resin layer is treated with resorcin formalin latex (RFL) (Japanese Patent No. 3304515). Etc.) are preferably used.

  As the cover rubber layer, natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), or a mixture of one or more polymers, nitrile rubber (NBR), ethylene propylene A rubber composition having a known composition mainly composed of rubber such as rubber (EPDM) mixed with carbon and oil and sulfur vulcanized or peroxide vulcanized can be used.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a part and% show a mass part and mass%.

[Examples 1 to 5, Comparative Examples 1 to 23]
A rubber composition having the composition shown in Tables 1 and 2 below was prepared, and the adhesive strength with a galvanized steel cord, vulcanization speed, roll workability, and laminating workability were evaluated by the following methods. The results are shown in Tables 1 and 2.

The details of each component shown in Tables 1 and 2 are as follows.
・ Natural rubber: RSS # 3
Styrene-butadiene rubber: SBR1500 (emulsion polymerization method SBR, manufactured by JSR)
・ Carbon black: Asahi Carbon Co., Ltd. “# 70”
・ Anti-aging agent: Sumitomo Chemical Co., Ltd. “ANTIGENE 6C”
Aroma oil: Idemitsu Kosan Co., Ltd. “Diana Process Oil AH-85”
・ Sulfur: Tsurumi Chemical Co., Ltd. “Z Sulfur”
・ Vulcanization accelerator: Ouchi Shinsei Chemical Co., Ltd. “Noxeller NS-F”
・ Zinc flower: Toho Zinc Co., Ltd.
・ Zinc dimethacrylate: Kawaguchi Chemical Industry Co., Ltd. “Actor ZMA”
・ Cobalt neodecanoate: DIC Corporation “Cobaltic acid cobalt”
・ Cobalt borate of neodecanoate: DIC Corporation “DICnate NBC-II”
・ Cobalt naphthenate: DIC Corporation “Cobalt naphthenate”
・ Cobalt stearate: DIC Corporation “Cobalt stearate”
・ Stearic acid: Kao Corporation “LUNAC RA”
Unsaturated fatty acid zinc: "EXTON L2", Kawaguchi Chemical Industry Co., Ltd.
・ Phenolic resin-1: Sumitomo Bakelite Co., Ltd. “Sumilite Resin PR-50235”
Phenol resin-2 (hexamethylenetetramine internal addition type): Sumitomo Bakelite Co., Ltd. “Sumilite Resin PR-12687”
・ Β-Naphthol: Mitsui Chemicals Fine Co., Ltd. “2-Naphthol”
・ Hexamethoxymethylated melamine: Nippon Cytec Industry “CYREZ964RPC”

(1) Adhesion test a. Preparation of Test Pieces Each component shown in Tables 1 and 2 was blended and kneaded using a Banbury mixer to obtain a rubber composition. A sheet (thickness 15 mm) of each rubber composition obtained was prepared, and an aramid canvas was epoxy-treated with glycerol polyglycidyl ether and further RFL-treated) between a pair of sheets, and 170 ° C., 40 minutes Pressure vulcanization was performed under the conditions to prepare a test piece. As the aramid canvas, an aramid cord using PPTA (manufactured by Toray DuPont, diameter 2.1 mm, structure: 3000D / 1/3/3) was epoxy-treated with glycerol polyglycidyl ether and further RFL-treated. A thing was used.
b. Moisture and heat resistant adhesive strength The test piece was allowed to stand for 21 days under conditions of 40 ° C. and humidity of 100% RH, and then the aramid canvas was pulled out of the test piece, and the pulling force was measured. In this case, the pull-out test was performed according to DIN 22131. Evaluation was indexed with the pulling force of Comparative Example 4 in Table 1 as 100. The higher the value, the larger and better the adhesive strength.

(2) Vulcanization speed The value of 155 ° C. and Tc (90) was measured by the method specified in JIS K6300-2. For measurement, “Charactometer W type” manufactured by Nichigo Corporation was used. The measurement value of Comparative Example 4 was set to 100, and the index was displayed so that the smaller the value of Tc (90), the larger the value.

(3) Treat workability Adjust the gauge of the three calendars so that the rubber is rolled to a thickness of 1 mm, and roll the rubber while inserting the aramid canvas (thickness 0.8 mm, made of nylon) from the back side. Pull out the canvas with rubber on one side. The workability at this time was evaluated as treat workability. The evaluation was made in three stages: good ◎, good ○, and poor ×.

(4) Lamination workability The unvulcanized rubber laminate shown in FIG. 1 was prepared as a sample. Samples were prepared by first kneading a cover rubber composition having the following composition with a Banbury mixer. Using this cover rubber composition, cover rubber layers 1 and 1 having a thickness of 4 mm were prepared and shown in Tables 1 and 2. Further, an aramid canvas 3 was sandwiched between adhesive rubber layers 2 and 2 each having a thickness of 2 mm formed of each rubber composition, which was further sandwiched between a pair of the cover rubber layers 1 and 1 and pressed by a hand roller.
(Cover rubber composition)
Natural rubber (RSS # 3) 70 parts by mass Styrene butadiene rubber (SBR 1500, manufactured by JSR) 30 parts by mass HAF carbon 55 parts by mass Stearic acid (Kao Corporation “LUNAC RA”) 3 parts by mass ZnO 3 parts by mass Wax (large Inner Emerging Chemical Industry “Sannok N”) 2 parts by mass anti-aging agent RD (Kawaguchi Chemical “ANTAGE RD”) 0.5 parts by mass anti-aging agent 6C (Kawaguchi Chemical “ANTAGE 6C”) 0.5 parts by mass aroma oil (Idemitsu) Kosan Co., Ltd. “Diana Process Oil AH-85”) 5 parts by mass sulfur 2 parts by mass vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd. “Noxeller NS-F”) 0.7 parts by mass Was forcibly peeled between the cover rubber layer / adhesive rubber layer, and the adhesiveness was evaluated as good ○, good Δ, and poor ×.

  As shown in Tables 1 and 2, the conveyor belt of the present invention has excellent adhesiveness between the core aramid canvas and rubber, and the rubber composition forming the adhesive rubber layer has good treat workability, lamination workability, It has a vulcanization speed and is excellent in productivity.

1 Cover rubber layer 2 Adhesive rubber layer 3 Aramid canvas

Claims (8)

In a conveyor belt in which an aramid canvas covered with an adhesive rubber layer is disposed as a core body between cover rubber layers,
The adhesive rubber layer is 0.5 to 3 parts by mass of zinc dimethacrylate, 1 to 10 parts by mass of cobalt neodecanoate, and 0.5 to 4 parts by mass of cobalt stearate with respect to 100 parts by mass of the rubber component. A conveyor belt, which is formed of a rubber composition containing the conveyor belt.   The conveyor belt according to claim 1, wherein the rubber composition contains one or both of cobalt neodecanoate and cobalt neodecanoate borate as the cobalt neodecanoate compound.   The conveyor belt according to claim 1 or 2, wherein 20 to 70 parts by mass of natural rubber and 80 to 30 parts by mass of synthetic rubber are contained in 100 parts by mass of the rubber component of the rubber composition.   The conveyor belt according to claim 3, wherein the synthetic rubber is one or more selected from styrene-butadiene rubber (SBR), butadiene rubber (BR), and isoprene rubber (IR).   The conveyor belt according to any one of claims 1 to 4, wherein the rubber composition contains 1 to 10 parts by mass of a phenol resin with respect to 100 parts by mass of the rubber component.   The conveyor belt according to claim 5, wherein the phenolic resin has hexamethylenetetramine added therein.   The conveyor belt according to any one of claims 1 to 6, wherein the rubber composition contains 1 to 10 parts by mass of β-naphthol with respect to 100 parts by mass of the rubber component.   8. The rubber composition according to claim 1, wherein the rubber composition contains 1 to 10 parts by mass of hexamethoxymethylated melamine and / or hexamethylenetetramine as a curing agent with respect to 100 parts by mass of the rubber component. Conveyor belt.

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