JP2006152106A - Rubber composition for aramid conveyer belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for an aramid conveyer belt, having a good peeling strength and rubber attachment with the aramid canvas and the aramid conveyer belt by using the rubber composition. <P>SOLUTION: This rubber composition for the aramid conveyer belt is provided by containing a diene-based rubber, an organic cobalt salt and an organic chlorine compound, wherein, 0.1-1.5 pts.mass organic cobalt salt as the amount of the cobalt, based on 100 pts.mass diene-based rubber and 2-17.5 pts.mass organic chlorine compound as the amount of chlorine, based on the 100 pts.mass diene-based rubber are contained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition for an aramid conveyor belt and an aramid conveyor belt using the rubber composition.

  “Conveyor belts”, which have the property of being transported continuously at a low cost and far away as a transportation means in industry, are used in a wide range of fields as “industrial aorta” in the era of mass and high-speed transportation. In particular, “Steel Cord Conveyor Belt” that enables mass transport over ultra-long distances, (1) High tension, large capacity and super-spun belt, (2) Less stretch and less take-up space (3) Excellent trough performance and no meandering, (4) Good travel performance, long belt life, etc. "Long distance", "High speed", "Large capacity transport" are required Has been widely used in the field.

In recent years, “aramid conveyor belts” that meet the needs of a new era such as energy saving and environmental measures have been used as such conveyor belts, and are being replaced by steel cord conveyor belts.
This aramid conveyor belt is a conveyor belt using “aramid fiber”, which has been attracting attention as a new material with less elongation like steel cords, as a canvas (aramid canvas) of a belt core (tension layer).

  As a technology relating to such an aramid conveyor belt, Patent Document 1 discloses that “an aromatic aramid fiber body having an epoxy resin layer treated with a resorcin formalin latex formed on its surface is 100 parts by weight of a diene raw rubber, an organic cobalt salt 0 An aramid fiber / rubber embedded in a vulcanized body of a rubber composition containing 0.05 to 15 parts by weight, phenols 0.5 to 10 parts by weight, and phenol formaldehyde resin 1 to 20 parts by weight Based composite materials ", and belts for belt conveyors are described as composite materials.

Japanese Patent Laid-Open No. 7-11012

  However, even with the aramid fiber / rubber-based composite material (belt conveyor belt) described in Patent Document 1, the adhesive force between the aramid canvas and the coated rubber sandwiching it (peeling force (N / inch) with rubber) (%)) May be insufficient, and it is clear that there is room for improvement, especially with rubber.

  Then, this invention makes it a subject to provide the aramid conveyor belt using the rubber composition for aramid conveyor belts with good peeling force and rubber | gum attachment with respect to an aramid canvas, and this rubber composition.

  As a result of intensive studies to solve the above problems, the present inventors have found that a rubber composition in which a specific amount of an organic cobalt salt and an organic chlorine compound is blended with a diene rubber is excellent in both peeling force and rubber attachment to an aramid canvas. As a result, the present invention has been completed. That is, this invention provides the rubber composition for aramid conveyor belts described in the following (1) and the aramid conveyor belt described in the following (2).

(1) containing a diene rubber, an organic cobalt salt, and an organic chlorine compound;
The organic cobalt salt is contained in an amount of 0.1 to 1.5 parts by mass with respect to 100 parts by mass of the diene rubber,
A rubber composition for an aramid conveyor belt containing 2 to 17.5 parts by mass of the above-mentioned organochlorine compound as a chlorine content with respect to 100 parts by mass of the diene rubber (first aspect).

  (2) An aramid conveyor belt using the rubber composition for an aramid conveyor belt described in (1) as a coat rubber layer (second embodiment).

  As will be described below, according to the present invention, it is possible to provide a rubber composition for an aramid conveyor belt which is excellent in both peeling force and rubber attachment to an aramid canvas, thereby achieving a longer life and higher strength. A conveyor belt can also be provided which is very useful.

The present invention is described in detail below.
The rubber composition for an aramid conveyor belt according to the first aspect of the present invention (hereinafter sometimes simply referred to as “the rubber composition of the present invention”) includes a diene rubber, an organic cobalt salt, an organic chlorine compound, Containing 0.1 to 1.5 parts by mass of the organic cobalt salt as a cobalt amount with respect to 100 parts by mass of the diene rubber, and the organochlorine compound with respect to 100 parts by mass of the diene rubber. Is a rubber composition for an aramid conveyor belt containing 2 to 17.5 parts by mass of chlorine.
Hereinafter, the diene rubber, the organic cobalt salt and the organic chlorine compound used in the rubber composition of the present invention will be described in detail.

<Diene rubber>
The diene rubber used in the present invention is not particularly limited as long as it is a conventionally known one. Specific examples thereof include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and 1,2-butadiene. Rubber, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene-diene rubber (EPDM) These may be used, and these may be used alone or in combination of two or more.
Of these, natural rubber, isoprene rubber, and styrene-butadiene rubber are preferably used from the viewpoint of the balance between elongation at break (E _B ), strength at break (T _B ) and processability, and particularly natural rubber and styrene-butadiene rubber. The use of the mixed rubber with the rubber can suppress heat generation during the mixing process of the resulting rubber composition of the present invention, and the characteristic that it is easy to form into a sheet during processing (particularly during roll rolling in a factory) ( In the following, it is also referred to as “roll workability”, which is more preferable.

<Organic cobalt salt>
The organic cobalt salt used in the present invention is generally used as a liquid phase oxidation catalyst and is not particularly limited as long as it is a conventionally known one. A cobalt acetate solution is added to an alkaline soap solution of a corresponding organic acid to metathesis. What is obtained by a method of precipitation, a method of heating and melting an organic acid and cobalt (II) oxide, a method of adding an aqueous solution of cobalt sulfate or cobalt nitrate to a benzine solution of an organic acid, and the like can be used.

Specific examples of the organic cobalt salt used in the present invention include, for example, cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt orthoborate, cobalt octylate, cobalt versatate, cobalt octylate, cobalt palmitate, and rosin. Examples thereof include cobalt oxide, cobalt propionate, and cobalt boron complex. These may be used alone or in combination of two or more.
Among these, cobalt naphthenate is preferable because the adhesiveness between the obtained rubber composition of the present invention and the aramid canvas is further improved.
As such an organic cobalt salt, a commercially available product can be used. Specifically, for example, 10% cobalt naphthenate manufactured by Dainippon Ink & Chemicals, Inc. can be used.

  In the rubber composition of the present invention, the content of such an organic cobalt salt is 0.1 to 1.5 parts by mass as a cobalt amount with respect to 100 parts by mass of the diene rubber. The amount is preferably 0.5 parts by mass.

<Organic chlorine compounds>
As the organic chlorine compound used in the present invention, an organic chlorine compound generally used as a chlorine-based flame retardant can be used, but a linear organic chlorine compound is preferably used. Specific examples of the linear organic chlorine compound include chlorinated paraffin and chlorinated polyethylene.
As such an organic chlorine compound, a commercial product can be used. Specifically, for example, ENPARA 70S (chlorinated paraffin, chlorine content 70%), ENPARA 40S (chlorinated paraffin) manufactured by Ajinomoto Fine Techno Co., Ltd. , Chlorine content 40%) and the like.

  In the rubber composition of the present invention, the content of such an organic chlorine compound is 2 to 17.5 parts by mass as a chlorine amount with respect to 100 parts by mass of the diene rubber, and 2 to 7 parts by mass. Preferably there is.

In the present invention, in the aramid conveyor belt using the obtained rubber composition of the present invention for the coated rubber layer, if the above organic cobalt salt and the above organic chlorine compound are contained in the above-mentioned ranges, respectively, Both the peeling force and the rubber attachment with the coated rubber layer to be sandwiched are good, and the rubber attachment is particularly excellent. This is considered to be because the cross-linking points between the aramid canvas and the coat rubber layer are increased.
In the present invention, the total content of the organic cobalt salt as a cobalt amount and the organic chlorine compound as a chlorine amount is 3 to 13 parts by mass with respect to 100 parts by mass of the diene rubber. It is preferable from the viewpoints of elongation at break and strength at break and roll processability.

In one preferred embodiment, the rubber composition of the present invention contains a vulcanizing agent.
Examples of the vulcanizing agent that can be used in the rubber composition of the present invention include sulfur-based, organic peroxide-based, metal oxide-based, phenolic resin, quinone dioxime, and the like.
Specific examples of the sulfur vulcanizing agent include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, alkylphenol disulfide, and the like.
Specific examples of the organic peroxide vulcanizing agent include benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di- (T-Butylperoxy) hexane, 2,5-dimethylhexane-2,5-di (peroxylbenzoate) and the like.
Other examples include magnesium oxide, risurge, p-quinonedioxime, p-dibenzoylquinonedioxime, poly-p-dinitrosobenzene, methylenedianiline, and the like.

In the rubber composition of the present invention, the content of such a vulcanizing agent is preferably 0.1 to 10 parts by mass, and 0.3 to 5 parts by mass with respect to 100 parts by mass of the diene rubber. More preferably, it is part.
If the content of the vulcanizing agent is within this range, the elongation at break (E _B ) and the fracture of the aramid conveyor belt according to the second aspect of the present invention (hereinafter simply referred to as “the conveyor belt of the present invention”) obtained. This is preferable because the balance between strength (T _B ) and hardness is excellent and fatigue resistance is improved.

  The rubber composition of the present invention contains a vulcanization accelerator, a vulcanization aid, a vulcanization retarder, and various compounding agents as necessary, in addition to the above-mentioned various components, as long as the object of the present invention is not impaired. May be.

Examples of the vulcanization accelerator include aldehyde / ammonia, guanidine, thiourea, thiazole, sulfenamide, thiuram, and dithiocarbamate vulcanization accelerators.
Specific examples of aldehyde / ammonia-based vulcanization accelerators include, for example, hexamethylenetetramine (H); specific examples of guanidine-based vulcanization accelerators include, for example, diphenylguanidine; thiourea-based vulcanization. Specific examples of the accelerator include, for example, ethylene thiourea; and examples of the thiazole vulcanization accelerator include, for example, dibenzothiazyl disulfide (DM), N-cyclohexyl-2-benzothiazolyl. Rusulfenamide (CZ), 2-mercaptobenzothiazole and its Zn salt, etc .; as thiuram vulcanization accelerator, specifically, for example, tetramethylthiuram disulfide (TMTD), dipentamethylene thiuram tetrasulfide, etc. Specific examples of the dithiocarbamate vulcanization accelerator include Na Dimethyl dithiocarbamate, Zn- dimethyldithiocarbamate, Te- diethyldithiocarbamate, Cu- dimethyldithiocarbamate, Fe- dimethyldithiocarbamate, pipecolic pin Pekori Le dithiocarbamate, and the like, respectively.

As the vulcanization aid, general rubber aids can be used together, and examples thereof include zinc white, stearic acid, oleic acid, and Zn salts thereof.
The content of the vulcanization accelerator and the vulcanization aid is preferably 0.1 to 10 parts by mass and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the diene rubber. .

Specific examples of the vulcanization retarder include organic acids such as phthalic anhydride, benzoic acid, salicylic acid, and acetylsalicylic acid; N-nitrosodiphenylamine, N-nitrosophenyl-β-naphthylamine, N-nitroso- Nitroso compounds such as polymers of trimethyl-dihydroquinoline; halides such as trichloromelanin; 2-mercaptobenzimidazole; santoguard PVI and the like.
The content of the vulcanization retarder is preferably 0.1 to 0.3 parts by mass, and more preferably 0.1 to 0.2 parts by mass with respect to 100 parts by mass of the diene rubber.

Examples of compounding agents include reinforcing agents (fillers), anti-aging agents, antioxidants, pigments (dyes), plasticizers, thixotropic agents, UV absorbers, flame retardants, solvents, surfactants (leveling agents). ), Dispersant, dehydrating agent, rust preventive agent, adhesion-imparting agent, antistatic agent, filler (filler), processing aid and the like.
As these compounding agents, those generally used for rubber compositions can be used. Their blending amounts are not particularly limited and can be arbitrarily selected.

  The rubber composition of the present invention is produced by kneading the above-described diene rubber, organic cobalt salt and organochlorine compound, and a compounding agent to be added as required, using a roll, a kneader, a Banbury mixer, etc. It can be carried out by adding a sulfur accelerator and kneading with a kneading roll machine or the like.

The conveyor belt of the present invention is an aramid conveyor belt using the rubber composition for an aramid conveyor belt according to the first aspect of the present invention described above as a coat rubber layer, specifically, a cover rubber layer, a coat rubber layer, An aramid conveyor belt provided with an aramid canvas, wherein the coated rubber layer is a conveyor belt formed of the rubber composition of the present invention.
Below, the conveyor belt of this invention is demonstrated using FIG. 1, However, The structure of the conveyor belt of this invention is not limited to this.

FIG. 1 is a cross-sectional view schematically showing an example of a preferred embodiment of the conveyor belt of the present invention. In FIG. 1, 1 is a conveyor belt, 2 is an upper surface cover rubber layer, 3 is an upper surface coat rubber layer, 4 is a reinforcing layer, 5 is a lower surface coat rubber layer, 6 is a lower surface cover rubber layer, and 7 is a transported material conveyance surface.
As shown in FIG. 1, the conveyor belt 1 has a reinforcing layer 4 as a central layer, and an upper surface coat rubber layer 3 and a lower surface coat rubber layer 5 are provided on both sides thereof, and further, an upper surface cover rubber layer 2 and an outer side thereof. A bottom cover rubber layer 6 is provided.

  In FIG. 1, the reinforcing layer 4 is composed of one layer, but in the present invention, the number of reinforcing layers is not limited to one, and may be two or more. When there are two reinforcing layers, a coat rubber layer is also provided between the reinforcing layers.

Here, the upper surface coat rubber layer 3 and the lower surface coat rubber layer 5 are formed of the rubber composition of the present invention, and the reinforcing layer 4 is an aramid canvas whose core is formed of aramid fibers. In addition, it is preferable to use what was immersed in the liquid mixture of the resorcin / formalin initial condensate aqueous solution and rubber latex as this aramid canvas (hereinafter referred to as “RFL treatment”).
Moreover, it is preferable that the upper surface cover rubber layer 2 which comprises the conveyed product conveyance surface 7 is formed from the rubber composition excellent in heat resistance, abrasion resistance, and oil resistance, and the lower surface cover rubber layer 6 which comprises the back surface is It is preferably formed from a rubber composition excellent in low tack and low friction.

The manufacturing method of the conveyor belt of this invention is not specifically limited, The method etc. which are normally used are employable.
Specifically, after kneading the raw materials using a roll, kneader, Banbury mixer, etc., it is then formed into a sheet shape for each cover rubber layer using a calendar, etc., and then each obtained layer is reinforced. The method of laminating | stacking in a predetermined | prescribed order so that a layer may be pinched | interposed and pressing for 10 to 60 minutes at the temperature of 150-170 degreeC is illustrated suitably.

  In the conveyor belt of the present invention, since the rubber composition of the present invention, which has both excellent peeling force against rubber and aramid canvas, is used for the coated rubber layer, it is possible to achieve long life and high strength.

Examples The rubber composition and conveyor belt of the present invention will be described in more detail below, but the present invention is not limited thereto.
(Examples 1-10 and Comparative Examples 1-7)
The rubber composition for each aramid conveyor belt was prepared with the composition components (parts by mass) shown in Table 1 below with respect to 100 parts by mass of the mixed rubber of NR50 parts by mass and SBR50 parts by mass. Each of the obtained rubber compositions was evaluated for elongation at break, break strength, roll processability, peeling force, and rubber as shown below. The results are shown in Table 1 below.

<Elongation at break, strength at break>
A dumbbell-shaped No. 3 test piece having a thickness of 2 mm was cut out from a vulcanized rubber composition obtained by vulcanizing each obtained rubber composition under a vulcanization condition of 148 ° C. for 45 minutes, and each dumbbell-shaped No. 3 test piece was cut out. , A tensile test (tensile speed: 200 mm / min) according to JIS K6251-1993 was performed, and elongation at break (E _B ) [%] and breaking strength (T _B ) [MPa] were measured at room temperature (25 ° C.). .

<Roll processability>
Evaluation of roll processability is performed by visually observing the roll surface at the time of roll rolling of each obtained rubber composition. If the rubber composition does not adhere to the roll surface, “○” is given. “Δ” indicates that the contact is slightly removed but can be removed, and “×” indicates that contact with the roll is difficult to remove.

<Peeling force>
Each rubber composition obtained was used as a coated rubber layer, an aramid canvas subjected to RFL treatment was used as a reinforcing layer, and vulcanized under a vulcanization condition of 148 ° C. for 45 minutes (size: width 2. 5 cm × depth 15 cm × height 0.5 cm), and the peeling force (N / inch) was measured by a two-layer peeling test.
FIG. 2 is a cross-sectional view illustrating a test body used in the two-layer peeling test of the example, where 10 is an adhesion test body, 11 is a coated rubber layer, and 12 is an aramid canvas.
In the two-layer peeling test, a cellophane film was sandwiched in advance at a part of one end of the coated rubber layer between the aramid canvas 12 at a stage before vulcanization, and after vulcanization, the both ends were peeled 180 degrees at a peeling rate of 50 mm / min. The separation force (N / inch) was measured.

<With rubber>
The surface of the aramid canvas after peeling by the two-layer peeling test was visually observed, and the rubber attachment with the rubber adhesion rate (%) was observed. When the breakage due to peeling occurs on the entire surface of the coated rubber layer, the rubber attachment is 100%, and the adhesion is the best.

In addition, as the rubber component and each component, those shown below were used.
・ Natural rubber (NR): STR20
Synthetic rubber (SBR): NIPOL 1502 (made by Nippon Zeon)
・ Carbon black: HAF (made by Showa Cabot)
・ Zinc flower: 3 types of zinc oxide (manufactured by Shodo Chemical Industries)
・ Stearic acid: Beads stearic acid (manufactured by NOF Corporation)
-Anti-aging agent: Non-flex OD-3 (manufactured by Seiko Chemical Co., Ltd.)
・ Sulfur: Oil-treated sulfur (Karuizawa Refinery)
・ Vulcanization accelerator: Dibenzothiazyl disulfide (Noxeller DM-PO, manufactured by Sanshin Chemical Industry Co., Ltd.)
Resorcinol resin: Sumilite resin PR-175 (manufactured by Sumitomo Durez)
・ Cobalt naphthenate: Cobalt naphthenate 10% (cobalt content 10%, manufactured by Dainippon Ink & Chemicals, Inc.)
-Chlorinated paraffin 1: Empara 70S (chlorine content 70%, manufactured by Ajinomoto Fine Techno Co., Ltd.)
-Chlorinated paraffin 2: Empara 40S (chlorine content 40%, Ajinomoto Fine Techno Co., Ltd.)

  From the results shown in Table 1, it can be seen that the rubber compositions shown in Examples 1 to 10 have good elongation at break, strength at break and roll processability, and these rubber compositions are used for the coated rubber layer. The manufactured conveyor belt was found to have good peeling force against rubber and a rubberized surface.

FIG. 1 is a cross-sectional view schematically showing an example of a preferred embodiment of the conveyor belt of the present invention. FIG. 2 is a cross-sectional view illustrating a test body used in the two-layer peeling test of the example.

Explanation of symbols

1: Conveyor belt 2: Upper surface cover rubber layer 3: Upper surface coat rubber layer 4: Reinforcement layer 5: Lower surface coat rubber layer 6: Lower surface cover rubber layer 7: Carrying material conveying surface 10: Adhesive specimen 11: Coat rubber layer 12: Aramid canvas

Claims (2)

Containing a diene rubber, an organic cobalt salt, and an organic chlorine compound;
Containing 0.1 to 1.5 parts by mass of the organic cobalt salt as a cobalt amount with respect to 100 parts by mass of the diene rubber,
A rubber composition for an aramid conveyor belt, containing 2 to 17.5 parts by mass of the organic chlorine compound as a chlorine content with respect to 100 parts by mass of the diene rubber.   An aramid conveyor belt using the rubber composition for an aramid conveyor belt according to claim 1 as a coat rubber layer.

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