JPS621537A - Conveyor belt for transporting oil sand - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a conveyor belt for transporting oil sand that has excellent oil sand non-adhesion properties.

(Prior art) Oil sands are petroleum resources with large reserves, especially in Canada and Venezuela, and Canada's Athabas oil sands are particularly famous as they contain about 1/3 of the world's reserves. . Taking Athabas oil sand as an example, it is formed by a thin water film covering fine silica sand grains, which is further surrounded by bitumen, and the water film also contains trace amounts of metals. It is. The oil sands generally contain 5-20% by weight of a heavy, viscous, tar-like substance, or bitumen, and are therefore commercially extracted as a petroleum resource. Collection methods include so-called open-pit mining and a method in which unnecessary components such as bitumen and silica sand are separated underground and collected, but Athabas Riki uses open-pit mining in which the overburden of the oil sand is removed and the oil sand is directly collected. The collected oil sands are then transported to an extraction and purification plant by a conveyor belt.

Conveyor belts that transport oil sand have conventionally used rubber belts made of mixed rubber compounds of natural rubber and styrene-butadiene rubber or acrylonitrile-butadiene rubber reinforced with steel cords. Oil sand adheres and accumulates, which not only contaminates the conveyor belt, but also obstructs the conveyor belt from moving straight, reducing its carrying capacity. For this reason, conventionally, relatively low-grade petroleum fractions such as dissolved oil and light oil are sprayed onto a conveyor belt as a non-adhesive liquid to prevent oil sand from adhering and then transported to an extraction and refining plant. There is. However, this method uses flammable molten oil or light oil, which poses a risk of fire, accelerates the deterioration of the conveyor belt, and increases collection costs. Therefore, in recent years, water has been used as a non-stick liquid in place of dissolved oil or diesel oil in summer, and an aqueous mixture of water, surfactant and antifreeze in winter has been used as a non-stick liquid. In addition to the extra cost of separating the oil sand due to antifreeze contamination with the sand, -50
At low temperatures such as °C, there is a risk that the non-adherent liquid itself may freeze.

In order to solve the above-mentioned problems, Japanese Patent Application Laid-open No. 58
-198548 and JP-A-58-198550 disclose non-adhesive vulcanized rubber made by vulcanizing a rubber composition made by mixing a highly polar material, for example, glycol such as ethylene glycol or propylene glycol. Conveyor belts having layers have been proposed. However, in order to obtain such non-adhesive vulcanized rubber, the conventional rubber processing method of kneading highly polar materials such as ethylene glycol and propylene glycol with rubber in an internal mixer does not allow for the uniform production of highly polar materials such as ethylene glycol or propylene glycol. The amount of material that can be incorporated into rubber is limited. For example, when kneading acrylonitrile-butadiene rubber with an acrylonitrile content of 20% by weight as the rubber and ethylene glycol as the highly polar material in an internal mixer, the amount of ethylene glycol is about 5% per 100 parts by weight of the rubber. Parts by weight is the maximum blending amount in normal kneading operations, and if this is exceeded, the rubber will slip on the roll surface during mixed wire processing using an internal mixer or oven roll. However, with this level of ethylene glycol content, the vulcanized rubber may still not have sufficient anti-stick properties.

(Object of the Invention) As a result of intensive research to solve the above-mentioned problems, the present inventors have discovered that a predetermined hydrophilic group-containing vinyl monomer is combined with a conjugated diene such as butadiene or isoprene and an α-, β- A rubber compound containing a terpolymer obtained by copolymerizing with an unsaturated nitrile has extremely high polarity because it contains the hydrophilic group-containing vinyl monomer component. can be easily blended with highly polar materials such as polyhydric alcohols, and the vulcanized rubber obtained by vulcanizing a rubber compound containing such unvulcanized rubber is
It has exceptional oil sand non-stick properties, and therefore,
It was discovered that a conveyor belt having such a vulcanized rubber as at least the surface layer is extremely suitable for conveying oil sand, leading to the present invention.

Accordingly, an object of the present invention is to provide a conveyor belt for conveying oil sand that is excellent in non-adhesion of oil sand.

(Structure of the Invention) The conveyor belt for conveying oil sand according to the present invention includes (al conjugated diene component unit 55 to 95% by weight, medium)
α, β-unsaturated nitrile 3 to 20% by weight, and (C) general formula % formula % (However, R1 is a hydrogen atom or a methyl group, R2 is an alkyl group with 3 to 3 carbon atoms, and n is 2 to 8 carbon atoms) 2 to 25 hydrophilic group-containing vinyl monomer component units represented by
% by weight of a terpolymer and 10 to 50 parts by weight of a liquid polyhydric alcohol as at least a surface layer.

Among the copolymer component units in the present invention, as the conjugated diene, for example, butadiene, isoprene, chloroprene, 1,3-pentadiene, hexadiene, etc. can be used. Butadiene or isoprene is preferred from the viewpoint of ease of copolymerization with the hydrophilic group-containing monomer described below; α, β-unsaturated nitriles include acrylonitrile,
Methacrylonitrile etc. can be used, but in particular,
Acrylonitrile is preferred.

The terpolymer in the present invention has the general formula % as a monomer component unit (where R1 is a hydrogen atom or a methyl group, and R2 has a carbon number of 1
-3 alkyl group is shown, and n shows the number of 2-8. ) Contains a hydrophilic group-containing vinyl monomer component represented by:

In the above general formula, R1 is a hydrogen atom or a methyl group, and R2 is a methyl group, an ethyl group, or a propyl group.

If R2 is a higher alkyl group equal to or higher than a butyl group, the resulting vulcanized rubber has poor affinity with water and oil resistance, and is therefore not suitable for use in the present invention. Further, in the above general formula, n is a number from 2 to 8, preferably from 2 to 4. When n is 1, the resulting vulcanized rubber does not have good cold resistance and also has poor oil resistance.

On the other hand, when n is 9 or more, the copolymerizability decreases, making it impossible to obtain the terpolymer used in the present invention.

Examples of such hydrophilic group-containing vinyl monomers include ethyl carbitol acrylate, ethyl carbitol methacrylate, methyl carpitol acrylate, methyl carpitol methacrylate, methyl triglycol acrylate, methyl triglycol methacrylate, Examples include ethyl triglycol acrylate, ethyl triglycol methacrylate, methyltetraglycol acrylate, methyltetraglycol methacrylate, propyl triglycol acrylate, and ethylpentaglycol methacrylate.

The hydrophilic group-containing vinyl monomer as described above can be prepared by mixing the corresponding acrylic acid or methacrylic acid constituting it with alkylene glycol "1-alkyl ether" in a conventional manner, for example, by mixing acrylic acid with 1/2 molar amount of the alkylene glycol "1-lkyl ether". Ethyl carbitol acrylate can be easily obtained by reacting diethylene glycol ethyl ether (carpitol) with an acid catalyst such as lyluenesulfonic acid under reflux for 2 hours.

In the present invention, in the terpolymer having monomer component units as described above, 55 to 55 conjugated diene component units are used.
95% by weight, α,β-unsaturated nitrile 3-20% by weight,
and 2 to 25% by weight of hydrophilic group-containing vinyl monomer component units. Preferably, the content is 67 to 91% by weight of conjugated diene component units, 4 to 13% by weight of α,β-unsaturated nitrile, and 5 to 20% by weight of hydrophilic group-containing vinyl monomer.

When the conjugated diene component unit is less than 55% by weight,
The resulting vulcanized rubber has insufficient cold resistance and is unsuitable as a surface layer for oil sand conveyor belts, which are often used in cold regions. On the other hand, when it exceeds 95% by weight, the oil resistance becomes poor and the affinity with water becomes poor. When the α, β-unsaturated nitrile component unit is less than 3% by weight, the oil resistance is poor, and when it exceeds 20% by weight, the elasticity is poor.
It is not preferable as a surface layer rubber for a conveyor belt, and has poor cold resistance, so it is also unsuitable as a surface layer for a conveyor belt for transporting oil sand.

Furthermore, the hydrophilic group-containing vinyl monomer component unit is 2 to 25 weight percent, or 5 to 20 weight percent, in the terpolymer. If it is less than 2% by weight, satisfactory polarity cannot be imparted to the vulcanized rubber, while if it exceeds 25% by weight, the elongation and strength are significantly reduced.
Not suitable for use on conveyor belts.

In addition, the terpolymer as described above has an intrinsic viscosity [η
] (in tetrahydrofuran at 30°C) is 1.0
~4.0 dl/g, preferably 135-3.0 dl/
It is g. This is because when the intrinsic viscosity is less than 1.0 dl/g, solid retention is poor and handling is difficult, whereas when it exceeds 4.0 dl/g, processability is poor.

The above-mentioned terpolymer includes, for example, 55 to 95% by weight of a conjugated diene monomer, 3% of an α,β-unsaturated nitrile monomer,
~20% by weight and the hydrophilic group-containing vinyl monomer 2-25
% by weight mixture in an aqueous medium or in an organic solvent by conventional radical copolymerization. Examples of radical polymerization initiators include organic peroxides such as benzoyl peroxide, cumene hydroperoxide, paramethane hydroperoxide, and lauroyl peroxide, bisazo compounds such as azobisisobutyl dinitrile, persulfates such as potassium persulfate, and organic A redox catalyst such as a combination of a compound and iron sulfate is used. A molecular weight regulator may also be used if necessary. As the molecular weight modifier, for example, t-dodecylmercaptan, dialkylxanthogen disulfide, etc. are used. The copolymerization reaction is usually carried out at a temperature of 0 to 50°C in an oxygen-free atmosphere.

In the present invention, a liquid polyhydric alcohol having a plurality of hydroxyl groups is used as a highly polar material that imparts further non-stick properties to the vulcanized rubber. Liquid polyhydric alcohols include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, and hexylene glycol, as well as glycerin, trimethylolpropane, hexanetriol, and pentyl alcohol. Preferred specific examples include trihydric or higher polyhydric alcohols such as erythritol, but especially low molecular weight, low viscosity liquids such as ethylene glycol and propylene glycol, and at normal rubber vulcanization temperatures. Polyhydric alcohols that do not easily evaporate at temperatures of 140 to 160°C are preferred.

In the present invention, the rubber compound is rubber 10 as described above.
The liquid polyhydric alcohol is contained in an amount of 10 to 50 parts by weight, preferably 10 to 30 parts by weight per 0 parts by weight. The amount of liquid polyhydric alcohol is 1 per 100 parts by weight of rubber.
If it is less than 0 parts by weight, the vulcanized rubber will have sufficient surface non-stick properties, but if it exceeds 50 parts by weight, it will be difficult to mix it uniformly with the rubber, and the vulcanized rubber will not be easily kneaded by the machine. This is undesirable because it deteriorates the physical properties.

In the present invention, the rubber compound contains an appropriate vulcanizing agent along with the above terpolymer and liquid polyhydric alcohol.

Sulfur and/or sulfur-containing compounds are usually blended as the vulcanizing agent. Any sulfur-containing compound may be used as long as it can vulcanize the terpolymer rubber, but for example, tetramethylthiuram disulfide, tetraethylthiuram disulfide, and the like are preferably used.

These vulcanizing agents are used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the terpolymer rubber. Further, a vulcanization aid may be used in combination with the vulcanizing agent. As the vulcanization aid, conventionally known ones can be used as appropriate. For example, as the vulcanization accelerator, diphenylguanidine, diorthotolylguanidine salt of dicatecolboric acid, 2-mercaptobenzothiazole,
Dibenzothiazyl disulfide, N-cyclohexyl-
2-benzothiazylsulfenamide, tetramethylthiuram monosulfide, etc., and metal oxides such as zinc white, magnesium oxide, litharge, etc. as vulcanization accelerating aids,
Examples include fatty acids such as stearic acid and oleic acid, amines such as triethanolamine and jetanolamine, and other activators such as diethylene glycol and triallyl trimellitate.

Further, in the present invention, the rubber compound may contain various commonly used fillers in addition to the above. For example, fillers include white carbon, carbon black, silica, calcium carbonate, clay, magnesium carbonate, diatomaceous earth, various silicates, and organic fillers. When blending these fillers, plasticizers such as di(2-ethylhexyl) phthalate, di(2-ethylhexyl) adipate, dibutyl phthalate, tri(2-ethylhexyl) trimellitate, tricresyl phosphate, and paraffinic process oils are used. , a softening agent such as aromatic process oil can be used in combination. Furthermore, phenyl-α-naphthylamine, N
, N'-diphenyl-p-phenylenediamine, 6-nitoxy2.2.4-trimethyl-1,2-dihydroquinoline, N-phenyl-N'-isopropyl-p-phenylenediamine, 2-mercaptobenzimidazole,
Antiaging agents such as nickel dibutyldithiocarbamate may also be used. If necessary, scorch inhibitors, processing aids, etc. are also used in combination.

In order to produce the rubber compound according to the present invention, the above components are usually kneaded using a Banbury mixer, a kneader mixer, a roll, or the like. Further, vulcanization of the rubber metal fittings is usually carried out by applying pressure at a temperature of 130 to 170°C for 10 to 60 minutes.

The conveyor belt according to the present invention has at least a surface layer of vulcanized rubber obtained by vulcanizing a rubber compound containing the above terpolymer and a liquid polyhydric alcohol, and is made of metal, organic fiber cord, canvas, etc. The conveyor belt reinforced in the longitudinal direction not only has excellent non-stick properties against oil sand, but also has excellent oil resistance, flexibility, and low-temperature properties, making it an excellent conveyor belt for transporting oil sand. demonstrate.

FIG. 1 shows a cross-sectional view of an example of a conveyor belt, in which a cushion rubber 3 is laminated and bonded between surface layers 1 and 2 that constitute the front and back sides of the conveyor belt, that is, cover rubber. A steel cord 4 as a core material is buried.

FIG. 2 shows a cross-sectional view of another example of a conveyor belt,
In order to strengthen the bond between the surface layers 1 and 2 and the cushion rubber 3, an intermediate rubber layer 5 is further laminated and bonded.

As the cushion rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, or a mixture thereof is preferably used. In particular, acrylonitrile-butadiene rubber with an acrylonitrile content in the range of 15 to 25% by weight has good cold resistance and oil resistance. It is particularly preferably used because of its excellent gender balance. The compounding agents such as vulcanizing agents and fillers in these cushion rubbers are well known in the art, but may be the same as in the case of the terpolymer rubber according to the present invention.

(Effect of the invention) As described above, the hydrophilic group-containing vinyl monomer α,
Regarding the β-unsaturated unsaturated citrile-conjugated diene copolymer, the terpolymer contained as a copolymer component unit of the acrylonitrile-butadiene copolymer itself has polarity. A large amount of liquid polyhydric alcohol can be blended into the vulcanized rubber, which is obtained by vulcanizing an unvulcanized rubber compound containing such liquid polyhydric alcohol. In addition to the unit, it has a significantly high polarity due to the liquid polyhydric alcohol.

Therefore, a conveyor belt having such a vulcanized rubber in its surface layer has a surface with extremely high polarity, and oil sand does not substantially adhere thereto during conveyance of the oil sand.

In addition, the belt can be transported from the collection point to the extraction and purification plant without spraying melt oil or water on the belt surface and without substantially adhering oil sand to the belt surface as in the conventional method.

In particular, the conveyor belt according to the present invention does not contain liquid polyhydric alcohol, since the liquid polyhydric alcohol leaches onto the surface of the conveyor belt and exhibits the same effect as when antifreeze is sprayed on the belt. Compared to a conveyor belt whose surface layer is made of vulcanized rubber made by vulcanizing the same rubber compound, it has better anti-adhesion properties from oil sand.

Furthermore, according to the conveyor belt of the present invention, even when an aqueous non-stick liquid containing water or antifreeze is sprayed on the conveyor belt surface, a water film is not formed on the conveyor belt surface because the surface layer is highly polar. As a result, it is not necessary to spray the non-adhesive liquid every time oil sand is loaded, and the number of times of spraying and consumption of the non-adherent liquid can be significantly reduced. Of course, since the conveyor belt of the present invention has excellent oil resistance, there is no problem in spraying melted oil or the like on its surface if necessary.

Therefore, according to the conveyor belt of the present invention, the cost of unnecessary non-adhesive liquid can be saved, the deterioration of the conveyor belt due to non-adherent liquid is less likely to occur, and the extra refining operation of collected oil sand due to contamination with water etc. can be avoided. can be omitted, reducing collection and purification costs. Furthermore, since there is no need to use a flammable non-adhesive liquid such as light oil, the risk of fire or the like caused by it is also eliminated.

(Examples) Examples of the present invention are listed below, but the present invention is not limited to these Examples. Note that in the following, parts indicate parts by weight.

Examples (Preparation of rubber compound and vulcanized rubber) 100 parts of a terpolymer consisting of the component units shown in the table, a predetermined amount of liquid polyhydric alcohol, carbon black (N-33
08AP) After mixing 55 parts of zinc oxide, 1 part of stearic acid, and 3 parts of anti-aging agent in an internal mixer, 2 parts of sulfur and 1.5 parts of vulcanization accelerator were further mixed in an oven roll. A rubber compound was prepared. Next, each rubber compound was vulcanized at 150° C. for 30 minutes, and then its physical properties were measured. The results are shown in the table.

For comparison, a commercially available acrylonitrile-butadiene rubber (N250S manufactured by Nippon Gosei Rubber, 20% by weight of bound acrylonitrile, 80% by weight of butadiene) was used as the rubber, and the same procedure as above was used except that no polyhydric alcohol was blended. A rubber compound was prepared, and after vulcanization at 150° C. for 30 minutes, its physical properties were measured. The results are shown in the table as Comparative Example 1.

Furthermore, for comparison, the above-mentioned terpolymer was included,
Rubber compound without liquid polyhydric alcohol (Comparative Example 2)
) was prepared, and a vulcanized rubber sheet was obtained in the same manner as above.

The results are shown in the table as Comparative Example 2.

The rubber compounds according to the present invention (Examples 1 to 17) were generally easy to knead and had good processability into sheets, but examples in which an excessive amount of ethylene glycol was blended as the polyhydric alcohol Regarding samples 3 and 4, processing was difficult.

(Oil sand adhesion test on rubber sheet) The following oil sand adhesion test was conducted on vulcanized rubber sheets obtained by vulcanizing the rubber compound according to the present invention and Comparative Examples 1 and 2. The rubber sheet is 21m thick, 30cm wide, and 3cm long.
It was set to 0CI11.

A first belt conveyor with a machine length of 9m, a second belt conveyor with a machine length of 9m, and a third belt conveyor with a machine length of 4m are arranged in a U-shape, and oil is transferred from the first to the second and from the second to the third. The test apparatus was constructed so that the sand could be conveyed sequentially, and each of the vulcanized rubber sheets obtained above was adhered to the second belt conveyor located in the center using an adhesive.

At an ambient temperature of 20-25° C., a hopper is installed on the end of the first belt conveyor, and 4 k of Canadian oil sands is poured from this hopper onto the end of the first belt conveyor.
g/min, and each belt conveyor was run for 20 minutes at a speed of 40 m/min. After 80 kg of oil sand was transported by each belt conveyor in this way, the oil sand adhering to the center part (area 10XIO) of the vulcanized rubber sheet on the second belt conveyor was scraped off with a spatula, and the weight was measured as the amount of oil sand adhesion. The results are shown in the table.

As is clear from the table, only a small amount of oil sand was attached to the vulcanized rubber sheet according to the present invention, whereas the conventional acrylonitrile-butadiene rubber compound (Comparative Example 1)
A large amount of oil sand adhered to the rubber sheet.

In addition, compared to the vulcanized rubber sheet made of the compound of Comparative Example 2, which uses a terpolymer and does not contain polyhydric alcohol, the vulcanized rubber sheet according to the present invention has a remarkable amount of oil sand attached. few.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing examples of conveyor belts. 1 and 2...Surface layer, 3...Cushion rubber, 4.
...Heartwood, 5...Intermediate rubber layer.

Claims (4)

[Claims] (1) (a) 55 to 95% by weight of conjugated diene component units, (
b) 3 to 20% by weight of α,β-unsaturated nitrile, and (c) general formula CH_2=CR^1COO-(CH_2CH_2O)_
n-R^2 (However, R^1 is a hydrogen atom or a methyl group, R
^2 represents an alkyl group having 1 to 3 carbon atoms, and n represents a number of 2 to 8 carbon atoms. ) 100 parts by weight of a ternary copolymer consisting of 2 to 25% by weight of hydrophilic group-containing vinyl monomer component units represented by 10 to 50 parts by weight of a liquid polyhydric alcohol is vulcanized. A conveyor belt for oil sands, characterized in that it has vulcanized rubber as at least a surface layer. (2) the conjugated diene is butadiene or isoprene,
A conveyor belt for transporting oil sand according to claim 1, characterized in that the α,β-unsaturated nitrile is acrylonitrile. (3) The conveyor belt for oil sand transport according to claim 1, wherein the hydrophilic group-containing vinyl monomer component unit is ethyl carbitol acrylate. (4) The conveyor belt for oil sand transport according to claim 1, wherein the hydrophilic group-containing vinyl monomer component unit is methyl triglycol acrylate.