WO2013190976A1

WO2013190976A1 - Conveyor belt

Info

Publication number: WO2013190976A1
Application number: PCT/JP2013/065159
Authority: WO
Inventors: 寛之尻池; 健桑鶴
Original assignee: バンドー化学株式会社
Priority date: 2012-06-22
Filing date: 2013-05-31
Publication date: 2013-12-27
Also published as: JPWO2013190976A1

Abstract

The present invention is a conveyor belt to carry transport goods through a transport path, wherein the invention is characterized in that at least one of a front face cover rubber and a back face cover rubber is formed from a flame-resistant rubber composition, and the flame-resistant rubber composition contains no less than 3 parts by weight and no more than 30 parts by weight of montmorillonite particles with respect to 100 parts by weight of a base rubber containing chloroprene. The generation of frictional heat in the conveyor belt can be suppressed by way of this configuration.

Description

Conveyor belt

The present invention relates to a conveyor belt that is used for transporting the transported object through a transport path on which a transported object is placed on the surface and surrounded by the periphery.

BACKGROUND ART Conventionally, a belt conveyor has been widely used as a conveying device for articles and the like, and various characteristics corresponding to applications are required for a conveyor belt that is a main component of the belt conveyor.
For example, a conveyor belt is required to have flame retardancy depending on the application. Patent Document 1 listed below has excellent flame retardancy for a conveyor belt by forming a cover rubber with a flame retardant rubber composition exhibiting a high oxygen index. It is described that it is given.

Japanese Unexamined Patent Publication No. 2009-249459

The conveyor belt is also widely used in ore mining sites and the like. For example, the conveyor belt is used to transport coal through a tunnel surrounded by a rock or the like in a coal mine.
Moreover, the said conveyor belt is utilized in the environment where the circumference | surroundings were enclosed besides the tunnel, for example, it is installed in the pipe body and is utilized for conveyance of articles | goods.
In such a case, it is difficult to visually recognize the traveling state of the conveyor belt during the conveyance directly from the outside.
Therefore, for example, even if a situation occurs in the middle of the conveyance path that causes the conveyor belt to slidably contact with an inner wall surface of a tunnel or a pipe body or other members constituting the belt conveyor for some reason, It is hard to be found early.

Conventionally, this point has not been particularly important, but the present inventor has analyzed the situation of the conveyor belt in the conveyance path, paying attention to this point.
As a result, the present inventor, when transporting an object that easily generates dust such as coal, rotates the roller by, for example, biting the dust into a roller bearing that supports the conveyor belt from the back side. We found that it was easy to make it defective.
And this inventor discovered that there exists a possibility of producing smoke and a fire on a conveyor belt by the frictional heat which arises between the roller which became poor rotation, and the conveyor belt.

For such a problem, as described in the above-mentioned patent document, a measure to make the cover rubber flame-retardant is effective in preventing smoke and fire of the conveyor belt.
The present inventor has found that suppressing the generation of frictional heat, which is the root cause of smoke generation and ignition, can be a more effective measure.
Conventionally, however, the above-mentioned problem has not been sufficiently recognized, and therefore, a method for preventing the generation of frictional heat in the conveyor belt has not been sufficiently studied.

In addition, in the point that it is difficult to grasp the situation in the conveyance path and that it may cause smoke and ignition by sliding contact with other members, etc., it is common even when things other than coal are conveyed through pipes etc. is there.
That is, the above problems are common to conveyor belts that are used for transporting a transported object through a transport path surrounded by the periphery.
And this invention makes it a subject to suppress generation | occurrence | production of the frictional heat in the conveyor belt used by the said conveyance path, and to prevent that a smoke and a fire arise in a conveyor belt by extension.

In order to solve the above-mentioned problems, the present invention is a conveyor belt that is used to transport a transported object through a transport path in which a transported object is placed on the surface and surrounded by the surface, and the surface side that constitutes the surface At least one of the cover rubber and the back surface side cover rubber constituting the back surface opposite to the front surface is formed of a flame retardant rubber composition, the flame retardant rubber composition includes a base rubber, Containing a flame retardant and montmorillonite particles, containing at least one chloroprene rubber as the base rubber, containing aluminum hydroxide, antimony trioxide, and chlorinated paraffin as the flame retardant, the base The ratio of the said montmorillonite particle with respect to 100 mass parts of rubber | gum is 3 mass parts or more and 30 mass parts or less, The conveyor belt characterized by the above-mentioned is provided.

In the present invention, at least one of the front side cover rubber and the back side cover rubber is formed of a flame retardant rubber composition having excellent flame retardancy, and frictional heat is generated in the flame retardant rubber composition. Montmorillonite particles effective for prevention are contained.
Therefore, the conveyor belt of the present invention can suppress the generation of frictional heat in the cover rubber, and can suppress the cover rubber from smoking and igniting.

The general use state figure of the belt conveyor provided with the conveyor belt of one Embodiment. FIG. 2 is a cross-sectional view taken along line XX in FIG. 1 showing a schematic cross-sectional structure of a conveyor belt according to an embodiment. Schematic showing the Australian standard test method implemented to rank the heat generation temperature due to friction. The graph showing the test result of the standard.

The preferred embodiments of the present invention will be described below.
First, based on the attached drawings, a belt conveyor using the conveyor belt of the present embodiment will be described by taking as an example a case where it is used to transport coal through a tunnel.

FIG. 1 is a diagram schematically showing a method of using a belt conveyor provided with the conveyor belt of the present embodiment, and FIG. 2 is a cross-sectional structure taken along the line XX indicated by a broken line in FIG. It is arrow sectional drawing which showed schematically.

FIG. 1 shows a state of the belt conveyor 1 in which the conveyor belt 10 of the present embodiment formed in an endless shape is arranged so as to have a constant upward gradient from the right side to the left side when viewed from the front in FIG. The state which sees the mode which conveys coal A through the mine shaft which attached | subjected the code | symbol 100 and was typically shown from the conveyance direction side is shown.
The belt conveyor 1 of the present embodiment includes the conveyor belt 10 and pulleys 20 arranged on one end side (loading side) and the other end side (unloading side) in the longitudinal direction of the transport path (tunnel). .
The conveyor belt 10 is provided between the pulley 20 and the belt conveyor 1.
Of the pair of pulleys 20 around which the conveyor belt 10 is stretched, the unloading pulley 20 is a driving pulley 21 connected to a driving source.
Another pulley 20 arranged on the stacking side is a driven pulley 22 that rotates together with the endless conveyor belt 10 circulated by the drive pulley 21.

The belt conveyor 1 according to the present embodiment further includes support rollers 30 disposed at a plurality of locations between the drive pulley 21 and the driven pulley 22.
Specifically, the belt conveyor 1 includes a plurality of forward path side support rollers 30a that support the conveyor belt 10 from the back surface side in a transport path (forward path) from the loading side to the unloading side.
Further, the belt conveyor 1 has its outer peripheral surface in contact with the surface of the conveyor belt 10 that faces downward in a path (return path) from the unloading side to the loading side so that the conveyor belt 10 And a plurality of return-path-side support rollers 30b.

That is, the driving pulley 21, the driven pulley 22, and the plurality of forward-side support rollers 30a are arranged at their respective upper ends while their rotational axes are arranged in parallel to each other so as to support the conveyor belt 10 in the outward path with a substantially constant inclination. Is provided on the belt conveyor 1 so that the vertical position of FIG.
In addition, as shown in FIG. 2, three outward support rollers 30a are arranged at one support location, the conveyor belt 10 is curved in the width direction, and the conveyor belt 10 is formed in a bowl shape in the entire outward path. It is arranged to run.
In other words, the three forward path support rollers 30a are arranged side by side with the rotation axis extending in the width direction of the conveyor belt 10, and of the three forward path support rollers 30a, two forward path side support rollers are provided. The rollers 30a are inclined and arranged so as to rise outward in the belt width direction in order to lift both side edges of the conveyor belt 10.
Further, the plurality of the return path side support rollers 30b are arranged so that their rotation axes are parallel to each other so that the conveyor belt 10 on the return path can be supported at a substantially constant inclination, and the vertical position of the upper end portion is lowered to the right in FIG. It is provided in the belt conveyor 1 so as to be.

In addition, the conveyor belt 10 in this embodiment is formed in the shape of a flat belt which is not provided with a horizontal beam crossing in the belt width direction and an ear beam standing along both side edges of the belt.
And the conveyor belt 10 in this embodiment is a cover rubber 11 which forms the surface side (outer peripheral side) of the conveyor belt 10 in which coal A is mounted, and the surface on the opposite side to the surface in which the said coal A is mounted. A two-layer cover rubber 11 with a cover rubber 11 constituting the back surface is provided.
The conveyor belt 10 further includes a canvas layer 12 in which a canvas for imparting tensile strength to the conveyor belt is embedded inside the two layers of cover rubber 11.

The conveyor belt 10 of this embodiment is used to transport the coal A through a transport path in which the transported object is coal A as described above and the tunnel 100 is surrounded.
Since the dust discharged from the coal A is easily filled in the mine shaft, the support roller 30 may interfere with smooth rotation because the dust enters a bearing or the like.
Moreover, the said support roller 30 has a possibility of becoming a state which cannot be rotated with dust depending on the case.
And, normally, while the conveyor belt 10 is running, it should generate only a small frictional heat due to rolling friction between the conveyor belt 10 and the support roller 30, but when the support roller 30 stops rotating, Frictional heat due to sliding friction is generated between the conveyor belt 10 and the support roller 30.
Usually, the sliding friction coefficient (dynamic friction coefficient) is 2 to 3 digits or more larger than the rolling friction coefficient, so that if the support roller 30 is unable to rotate, there is a risk of generating a great amount of frictional heat.

In particular, since the coal A is loaded in the forward path, the conveyor belt 10 is in a state in which a large load is applied between the back surface thereof and the outer peripheral surface of the roller 30, and the support roller 30 becomes unable to rotate. The back surface is heated to a high temperature by frictional heat, and in some cases, there is a risk of smoking or ignition.
For this reason, the conveyor belt 10 includes a front cover rubber 11 (hereinafter also referred to as “front cover rubber 11a”) and a back cover rubber 11 (hereinafter also referred to as “back cover rubber 11b”). It is preferable to form at least the back rubber 11b on the inside in a state excellent in flame retardancy and slipperiness.

In order to impart flame retardancy and slipperiness to the back side cover rubber 11b, the back side cover rubber 11b is made of a flame retardant rubber composition containing a flame retardant and a slipperiness imparting agent in addition to the base rubber. What is necessary is just to form.
In addition, as the flame retardant rubber composition for forming the back side cover rubber 11b, the rubber (base rubber) serving as a base of the flame retardant rubber composition may be one or more types of chloroprene rubber. is important.
More specifically, the flame retardant rubber composition of the present embodiment contains a base rubber (A) composed of one or more chloroprene rubbers and a flame retardant (B), and aluminum hydroxide is used as the flame retardant. It is important to use (B1), antimony trioxide (B2), and chlorinated paraffin (B3), and further containing montmorillonite particles (C) as the slipperiness-imparting agent. .
The flame retardant rubber composition may further contain a general rubber chemical (D) such as a vulcanizing agent.
Below, each component is demonstrated in detail.

(A) Base rubber The base rubber constituting the flame retardant rubber composition may be a single type of rubber or a mixed rubber obtained by mixing a plurality of types of rubber, but at least chloroprene rubber should be contained. is important.
This chloroprene rubber is excellent in flame retardancy by containing chlorine, which can be expected to have a radical scavenging action, in the molecule.
In other words, in general, in the thermal decomposition of polymers, radicals generated by molecular chain scission promote further molecular scission and promote thermal decomposition. However, chloroprene rubber captures radicals and stabilizes them. Degradation can be made gradual.
Moreover, since the chloroprene rubber generates nonflammable hydrogen chloride as the pyrolysis gas, it has an action of quickly shutting off the supply of oxygen to the conveyor belt that has started combustion with the pyrolysis gas and extinguishing the flame.
In this respect, it is important that the flame retardant rubber composition contains chloroprene rubber.

The chloroprene rubber is not particularly limited, and examples thereof include those commercially available from Showa Denko Co., Ltd. under the product names “Showrene W”, “Showrene WM1”, “Showrene G”, and “Denka Chloroprene”. PM-40 "," Denkachloroprene S-41 "and other" Denkachloroprene "series names commercially available from Denki Kagaku Kogyo Co., Ltd. are used alone, or a plurality of these are included in the base rubber. be able to.

In addition, the base rubber can contain a small amount of rubber other than the chloroprene rubber, for example, chlorinated polyethylene such as chlorinated polyethylene and chlorosulfonated polyethylene that can be expected to have the same function as chloroprene. You may let them.
Furthermore, if necessary, in addition to the chloroprene rubber, non-chlorine rubbers such as natural rubber and ethylene / α-olefin rubber can be contained as a part of the base rubber.

However, since the non-chlorine-based rubber has a risk of reducing the flame retardancy of the flame retardant rubber composition as the content ratio thereof is increased, the ratio of the non-chlorine rubber to the base rubber is preferably 20% by mass or less. The content is more preferably 10% by mass or less, and particularly preferably 5% by mass or less.
The base rubber is most preferably composed of only a chlorinated rubber.

In the case where the base rubber is composed of only a chlorinated rubber, the proportion of the other chlorinated rubber in the total of the chloroprene rubber and the other chlorinated rubber is preferably 20% by mass or less. % Or less, more preferably 5% by mass or less.

(B) Flame retardant (B1) Aluminum hydroxide The aluminum hydroxide exhibits a dehydration reaction at a temperature lower than the thermal decomposition start temperature (about 300 ° C.) of general polymers such as chloroprene rubber, and the dehydration reaction is endothermic. Because it is a reaction, it has the effect of lowering the temperature of the flame retardant rubber composition during the thermal decomposition of the flame retardant rubber composition, and is an important component for imparting flame resistance to the conveyor belt. .
Aluminum hydroxide also works effectively to form a heat-insulating coating with char during combustion, for example, when the back cover rubber is heated above the thermal decomposition temperature by frictional heat with the support roller. Then, char can be formed on the surface of the cover rubber to prevent the heat generated on the surface from being transmitted to the inside in the thickness direction.

The aluminum hydroxide is not particularly limited, but, for example, those having a relatively small particle diameter and a large specific surface area with a median diameter of about 2 μm or less have superior mechanical properties as a flame-retardant rubber composition. It is advantageous for exhibiting excellent flame retardancy.
Such fine aluminum hydroxide having a particle diameter is commercially available from Showa Denko KK under the series name of “Hijilite” such as “Hijilite H-42” and “Hijilite H-43M”. Things.

The aluminum hydroxide is more advantageous in terms of flame retardancy as the content in the flame retardant rubber composition is larger. On the other hand, if excessively contained, the mechanical properties of the cover rubber formed by the flame retardant rubber composition are increased. There is a risk of deteriorating the characteristics.
Therefore, the flame retardant rubber composition is water-soluble at a ratio of 30 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the base rubber in that the flame retardancy and mechanical properties can be exhibited in a balanced manner. It is preferable to contain aluminum oxide.

(B2) Antimony trioxide The antimony trioxide exhibits little flame retardancy by itself, and has a function of improving the flame retardant effect of the flame retardant when used in combination with a halogen-based flame retardant such as chlorinated paraffin. Is.
More specifically, antimony trioxide (Sb ₂ O ₃ ) supports the radical scavenging function of chlorine contained in chlorinated paraffin, chloroprene, etc. and reacts with hydrogen chloride generated by these thermal decompositions to react with oxychloride. When changing to antimony (SbOCl) or antimony trichloride (SbCl ₃ ), water vapor is generated and oxygen is blocked.

The antimony trioxide is a commercial product marketed by Nippon Seiko Co., Ltd. under the product name “PATOX-M”, “PATOX-K”, etc. It can be a commercial product commercially available from the company.
The flame retardant rubber composition usually has an antimony trioxide ratio of 1 to 15 parts by mass, preferably 2 to 10 parts by mass with respect to 100 parts by mass of the base rubber. Can be contained.

(B3) Chlorinated paraffin The chlorinated paraffin is commercially available from Ajinomoto Fine Techno Co., Ltd. under the series name “Empara” such as “Empara 40”, “Empara 70”, “Empara K-45”, etc. And those commercially available from Tosoh Corporation under the “Toyoparax” series name.
The flame-retardant rubber composition can usually contain the chlorinated paraffin at a ratio of 10 parts by mass to 30 parts by mass with respect to 100 parts by mass of the base rubber.

(C) Montmorillonite Particles Montmorillonite as a mineral is classified as a dioctahedral water-containing layered silicate mineral and is generally expressed by the following chemical formula.

(Al _2−y Mg _y ) Si ₄ O ₁₀ (OH) _2. (M ⁺ .M _1/2 ²⁺ ) _y nH ₂ O

(However, y usually represents a value of 0.2 to 0.6, M represents an exchangeable cation and represents Na, K, Ca, Mg, H, etc. n represents interlayer water. A number representing the quantity.)

More specifically, montmorillonite having the following chemical formula is known.

(Na.Ca) _0.33 (Al _1.67 Mg _0.33 ) Si ₄ O ₁₀ (OH) ₂ .nH ₂ O

The montmorillonite particles have an effect of causing delamination on the surface of the cover rubber and exhibiting excellent slipperiness on the conveyor belt.
As the montmorillonite particles, those having a particle size of 2 μm or less when dispersed in the cover rubber are preferable. For example, “Bengel HVP” and other “Bengel” series names are commercially available from Hojun Co. Organic processed products marketed under the series name "can be used.

In order to reliably exert the effect of montmorillonite particles on the conveyor belt, it is necessary to contain the montmorillonite particles to a certain extent in the flame-retardant rubber composition for forming the cover rubber. If it is contained in, there is a risk of deteriorating the wear resistance of the cover rubber.
Therefore, in order to make the cover rubber exhibit excellent sliding properties and wear resistance, the montmorillonite particles are added in a proportion of 3 to 30 parts by mass with respect to 100 parts by mass of the base rubber. It is important to include in the composition.
Specifically, the flame retardant rubber composition has 5 parts by mass or more and 15 parts by mass of the montmorillonite particles with respect to 100 parts by mass of the base rubber, in order to more effectively exhibit the effects of slipperiness and wear resistance. It is preferable to contain it in the ratio below the part.

(D) Other rubber chemicals Examples of the rubber chemicals include, for example, vulcanizing agents such as sulfur and organic peroxides; vulcanization accelerators such as sulfenamide compounds and thiazole compounds, fillers, softeners, Examples include aging inhibitors and processability improvers.
Further, the flame retardant rubber composition may contain a flame retardant other than the above, if necessary.
Further, the flame retardant rubber composition may contain particles made of layered clay minerals such as mica, clay, talc, etc. as a slipperiness imparting agent other than the montmorillonite particles, if necessary.

In addition, the conveyor belt may be formed of the flame retardant rubber composition so as to impart flame retardancy to both sides, similarly to the back side cover rubber 11b.
At this time, the flame-retardant rubber composition used for forming the back-side cover rubber 11b and the front-side cover rubber 11a may have the same content or different content.

The canvas for forming the canvas layer 12 is not particularly limited, and a canvas used for a general conveyor belt can be used 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 prepared, for example, by kneading a flame retardant rubber composition for a cover rubber using a Banbury mixer, a kneader mixer, a roll or the like, and then making the flame retardant rubber composition into a sheet using a calendar or the like. An unvulcanized sheet for cover rubber can be produced, and the unvulcanized sheet and canvas can be integrated by vulcanization.

More specifically, for the conveyor belt, a rubberized canvas is prepared, and the canvas is further sandwiched from outside by an unvulcanized sheet for cover rubber, and “unvulcanized sheet for cover rubber / canvas / unvulcanized for cover rubber”. A laminated body laminated in the order of “sulfur sheet” is formed, and the laminated body can be produced by vulcanization integration using a hot press.

In this embodiment, as an example in which the effect of the present invention is more remarkably exhibited, the case where the conveyed product is coal and a conveyance path through a mine shaft is provided, but the conveyor belt of the present invention is exemplified. Is effective even in cases where materials other than coal are transported through the inside of a tubular body such as a concrete pipe or an iron pipe.
That is, the conveyor belt in such an application is also intended as the conveyor belt of the present invention.

Further, in the present embodiment, the case where the rotation of the support roller is disabled as a cause of the generation of frictional heat is illustrated, but for example, the conveyed object dropped in the middle of the conveyance path and the conveyor belt come into contact. It is also possible to generate frictional heat.
Therefore, the conveyor belt of the present invention is not limited to the one supported and used by the support roller, and the object for imparting flame retardancy and slipperiness is not limited to the back side cover rubber. .
That is, a conveyor belt in which the flame retardant rubber composition containing the montmorillonite particles on which the conveyed product is placed is used only for the formation of the surface side cover rubber is also within the range intended as the conveyor belt of the present invention. It is.
Furthermore, the conveyor belt of the present invention is not limited to the flat belt illustrated in the present embodiment, but also has a cross rail that traverses in the belt width direction and a belt that has ear rails erected along both side edges. It is the range which is intended as the conveyor belt of this invention.
As a conveyor belt of the present invention, it is a matter of course that the conveyor belt exemplified in the embodiment may be modified in various ways other than the above.

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

(Materials used)
Table 1 below shows the abbreviations and specific contents of the raw materials used in the evaluation.

Samples for evaluation were prepared using a flame retardant rubber composition containing the above raw materials in the blending ratio shown in Table 2, and each evaluation was performed.

(Evaluation)
(Evaluation of slipperiness)
A belt-like sample is prepared by each blending, and the friction temperature is evaluated based on the Australian standard (AS1334.111-1988 “DETERMINATION OF IGNITABILITY AND MAXIMUM SURFACE TEMPERATURE OF BELTING SUBRECTED TO FRICTION”). Carried out.

The evaluation was performed using an apparatus as shown in FIG. 3 defined in the same standard.
That is, one end in the longitudinal direction of a belt-shaped sample 10x having a cover rubber formed of the flame-retardant rubber composition shown in Table 2 is fixed to the vertical wall WL, and the belt-shaped sample 10x is moved horizontally away from the fixed position. And a rotary drum TD having a diameter of 212.8 mm disposed so that the rotation axis is orthogonal to the longitudinal direction of the belt-shaped sample 10x at a position away from the vertical wall WL. The belt-shaped sample 10x is extended in the horizontal direction so that the belt-shaped sample 10x is wound around the outer peripheral surface of the rotating drum TD halfway and further approaches the vertical wall WL. Before reaching the vertical wall WL, it is wound around a rotatable auxiliary roll RL and the remaining part is suspended downward, and a load of 35 kg is set on the lower end of the suspended belt-like sample 10x. It was.
That is, the evaluation was performed by generating a tension of 35 kgf from one end in the length direction fixed to the vertical wall WL to the other end where the load was set.
The evaluation was performed by rotating the rotating drum TD at a rotation speed of 190.2 rpm using the motor MT in the above-described state.
At this time, the rotating drum TD was rotated so that the upper end side thereof moved away from the vertical wall WL.
Then, the highest temperature reached by the surface temperature of the belt-like sample 10x (the temperature of the surface in contact with the rotating drum TD) at the position in contact with the rotating drum TD during the test time of about 2 hours was measured.

As a result, the case where the maximum attained temperature was less than 250 ° C. was ranked “A”, and the case where the maximum attained temperature was 250 ° C. or more and less than 300 ° C. was ranked “B”.
Furthermore, the case where the maximum temperature reached 300 ° C. or higher and lower than 325 ° C. was ranked “C”, and the case where the maximum temperature reached 325 ° C. or higher was ranked “D”.
The results are also shown in Table 2 above.
Note that the evaluation of the belt-like sample of Comparative Example 7 was terminated in the middle because of the occurrence of glow.

Here, test conditions of Comparative Examples 7 to 9 and Example 9 are shown in FIGS.
FIGS. 4A to 4D are charts showing how the temperature of the belt-like sample has changed over time, and the friction coefficient (lower chart) calculated based on the temperature (upper chart) is also shown. It is also shown.
Also from this chart and the results shown in Table 2, it can be seen that according to the present invention, it is possible to obtain a conveyor belt which is excellent in sliding property and generation of frictional heat is suppressed.

The evaluation samples were ranked in wear resistance by the DIN abrasion test of JIS K6264-2 “Vulcanized rubber and thermoplastic rubber—How to obtain abrasion resistance—Part 2: Test method”.
At this time, the case where the wear amount of DIN wear was less than 200 mm ³ was ranked “A”, and the case where the wear amount was 200 mm ³ or more and less than 250 mm ³ was ranked “B”.
Furthermore, the case where the wear amount was 250 mm ³ or more and less than 300 mm ³ was ranked “C”, and the case where the wear amount was 300 mm ³ or more was ranked “D”.
The results are also shown in Table 2 above.
From this result, it can be seen that according to the present invention, a conveyor belt excellent in slipperiness can be obtained.

1: Belt conveyor, 10: Conveyor belt, 11: Cover rubber, 12: Canvas layer, 20: Pulley, 30: Support roller

Claims

It is a conveyor belt that is used for transporting the transported object through a transport path on which a transported object is placed and surrounded by a surface,
At least one of the surface side cover rubber constituting the surface and the back side cover rubber constituting the back surface opposite to the surface is formed of a flame retardant rubber composition, and the flame retardant rubber The composition contains a base rubber, a flame retardant, and montmorillonite particles, the base rubber contains at least one kind of chloroprene rubber, and the flame retardant contains aluminum hydroxide, antimony trioxide, and chlorinated paraffin. The conveyor belt characterized by containing and the ratio of the said montmorillonite particle with respect to 100 mass parts of said base rubbers being 3 mass parts or more and 30 mass parts or less.
The conveyor belt according to claim 1, wherein the back side cover rubber is formed of the flame retardant rubber composition.
The conveyor belt according to claim 1 or 2, wherein the flame retardant rubber composition has a ratio of the montmorillonite particles to 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the base rubber.
The conveyor belt according to any one of claims 1 to 3, wherein the transport path is a mine shaft, and the transported material is coal.