A conveyor belt with an upper convex herringbone pattern and its preparation process

Abstract

The present invention relates to the technical field of conveyor belts, and proposes a conveyor belt with an upper convex herringbone pattern and a preparation process thereof. The conveyor belt with an upper convex herringbone pattern comprises a belt core, an upper covering rubber layer arranged on the outside of the belt core, and a lower covering rubber layer arranged on the inside of the belt core. The upper covering rubber layer and the lower covering rubber layer are each independently composed of covering rubber, and the covering rubber includes the following components in parts by mass: 60 to 80 parts of natural rubber, 20 to 40 parts of nitrile rubber, 30 to 50 parts of filler, 5 to 10 parts of compatibilizer, 1 to 3 parts of antioxidant, 2 to 4 parts of vulcanizer, and 0.5 to 2.5 parts of accelerator; the compatibilizer includes epoxidized natural rubber and / or bis(2-hydroxyethyl)amino(trimethylol)methane. Through the above technical solution, the problem of poor compatibility of natural rubber and nitrile rubber blend materials in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of conveyor belts, and in particular to a conveyor belt with an upper convex herringbone pattern and a preparation process thereof. Background Art

[0002] Conveyor belts are important components for carrying and transporting materials on belt conveyors. They are widely used in heavy industrial fields such as mining, coal, ports, metallurgy, grain, electricity, and chemicals. They are suitable for long-distance and high-speed transportation of materials. Their share in rubber industry products has jumped to second place.

[0003] The rubber conveyor belt product series includes heat-resistant, high-temperature resistant, oil-resistant, acid- and alkali-resistant, flame-retardant, flame-retardant, cold-resistant, tubular, and tear-resistant series. Among these series, the wear resistance of rubber is an important technical indicator pursued by the industry, and the study of rubber wear performance is one of the hot topics in tribology research today.

[0004] Natural rubber offers advantages such as good elasticity, wear resistance, high mechanical strength, and good acid and alkali resistance, but it suffers from disadvantages such as poor aging resistance, oil resistance, and swelling resistance. Nitrile rubber, a copolymer of 1,3-butadiene and acrylonitrile, possesses excellent physical and mechanical properties and processing characteristics. Due to the presence of -CN- bonds in its molecular chain, nitrile rubber exhibits excellent oil resistance and better heat resistance than natural rubber, butadiene rubber, and styrene-butadiene rubber. Furthermore, due to the low price, good supply, and ease of mass production of natural rubber and nitrile rubber, most wear-resistant conveyor belts currently on the market are made by combining natural rubber and styrene-butadiene rubber. However, since natural rubber is non-polar and nitrile rubber is polar, the two are incompatible when blended, significantly reducing the mechanical strength and wear resistance of the conveyor belts, greatly limiting their application. Summary of the Invention

[0005] The invention provides a conveyor belt with an upward convex herringbone pattern and a preparation process thereof, which solves the problem of poor compatibility of natural rubber and nitrile rubber blend materials in the related art.

[0006] The technical solutions of the present invention are as follows:

[0007] A conveyor belt with an upper convex herringbone pattern, comprising a belt core, an upper covering rubber layer disposed on the outer side of the belt core, and a lower covering rubber layer disposed on the inner side of the belt core, wherein the upper covering rubber layer and the lower covering rubber layer are each independently composed of covering rubber, and the covering rubber comprises the following components in parts by weight: 60-80 parts of natural rubber, 20-40 parts of nitrile rubber, 30-50 parts of filler, 5-10 parts of compatibilizer, 1-3 parts of antioxidant, 2-4 parts of vulcanizer, and 0.5-2.5 parts of accelerator;

[0008] The compatibilizer includes epoxidized natural rubber and / or bis(2-hydroxyethyl)amino(trishydroxymethyl)methane.

[0009] As a further technical solution, the compatibilizer includes epoxidized natural rubber and bis(2-hydroxyethyl)amino(trihydroxymethyl)methane.

[0010] As a further technical solution, the mass ratio of the epoxidized natural rubber to bis(2-hydroxyethyl)amino(trihydroxymethyl)methane is 5-7:1-3.

[0011] As a further technical solution, the mass ratio of the epoxidized natural rubber to bis(2-hydroxyethyl)amino(trihydroxymethyl)methane is 3:1.

[0012] As a further technical solution, the epoxidized natural rubber includes one or more of ENR25, ENR50, and ENR75.

[0013] As a further technical solution, the filler includes one or more of carbon black and talc.

[0014] As a further technical solution, the antioxidant includes one or more of antioxidant 4010NA, antioxidant 4020, and antioxidant RD.

[0015] As a further technical solution, the vulcanizing agent includes one or more of sulfur and organic peroxides.

[0016] As a further technical solution, the accelerator includes one or more of sulfenamides and thiurams.

[0017] As a further technical solution, the accelerator includes one or more of N,N-diisopropyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide.

[0018] The present invention also proposes a preparation process for a conveyor belt with an upper convex herringbone pattern, comprising the following steps:

[0019] S1, after masticating and banburying the natural rubber, epoxidized natural rubber and nitrile rubber, adding bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, filler and antioxidant for primary mixing, adding vulcanizing agent and accelerator for secondary mixing, and extruding to obtain covering rubber;

[0020] S2. Place the covering rubber on the inner and outer sides of the belt core respectively, perform vulcanization, and form the belt to obtain a conveyor belt with an upward convex herringbone pattern.

[0021] The working principle and beneficial effects of the present invention are:

[0022] 1. The present invention uses epoxidized natural rubber and / or bis(2-hydroxyethyl)amino(trimethylol)methane as a compatibilizer for natural rubber and acrylonitrile-butadiene rubber blend materials. On the one hand, the molecular chain of the epoxidized natural rubber does not contain epoxy groups and can have good compatibility with natural rubber. On the other hand, since the bis(2-hydroxyethyl)amino(trimethylol)methane molecular structure contains hydroxyl and amino groups, it can form hydrogen bonds with the nitrile groups on the acrylonitrile-butadiene rubber molecular chain and can also interact with the epoxy groups on the epoxidized natural rubber molecular chain skeleton. Thus, the compatibility of natural rubber and acrylonitrile-butadiene rubber is increased, the problem of poor compatibility of natural rubber and acrylonitrile-butadiene rubber blend materials in the prior art is solved, and the mechanical strength and wear resistance of the conveyor belt are improved.

[0023] 2. The present invention limits the compatibilizer to epoxidized natural rubber and bis(2-hydroxyethyl)amino(trihydroxymethyl)methane in a mass ratio of 5-7:1-3, which further improves the compatibility of natural rubber and nitrile rubber, and further improves the mechanical strength and wear resistance of the conveyor belt. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] Example 1

[0026] 70 parts of natural rubber, 8 parts of ENR50 and 30 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 40 parts of carbon black and 2 parts of antioxidant 4010NA were added and mixed at 120°C for 4 minutes. 2.5 parts of sulfur and 1 part of tetramethylthiuram disulfide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0027] Example 2

[0028] 70 parts of natural rubber and 30 parts of nitrile rubber were plasticized on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 8 parts of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 40 parts of carbon black, and 2 parts of antioxidant 4010NA were added and mixed at 120°C for 4 minutes. 2.5 parts of sulfur and 1 part of tetramethylthiuram disulfide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0029] Example 3

[0030] 70 parts of natural rubber, 6 parts of ENR50 and 30 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 2 parts of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 40 parts of carbon black and 2 parts of antioxidant 4010NA were added and mixed at 120°C for 4 minutes. 2.5 parts of sulfur and 1 part of tetramethylthiuram disulfide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0031] Example 4

[0032] 70 parts of natural rubber, 5 parts of ENR50 and 30 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 3 parts of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 40 parts of carbon black and 2 parts of antioxidant 4010NA were added and mixed at 120°C for 4 minutes. 2.5 parts of sulfur and 1 part of tetramethylthiuram disulfide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0033] Example 5

[0034] 70 parts of natural rubber, 7 parts of ENR50 and 30 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 1 part of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 40 parts of carbon black and 2 parts of antioxidant 4010NA were added and mixed at 120°C for 4 minutes. 2.5 parts of sulfur and 1 part of tetramethylthiuram disulfide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0035] Example 6

[0036] 60 parts of natural rubber, 3.75 parts of ENR75 and 40 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 1.25 parts of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 30 parts of carbon black and 1 part of antioxidant 4020 were added and mixed at 120°C for 4 minutes. 2 parts of sulfur and 0.5 parts of N,N-diisopropyl-2-benzothiazolesulfenamide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0037] Example 7

[0038] 80 parts of natural rubber, 7.5 parts of ENR25 and 20 parts of nitrile rubber were masticated on an open mill at 55°C for 20 minutes, and then banburyed at 80°C for 2 minutes. 2.5 parts of bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, 50 parts of talc and 3 parts of antioxidant RD were added and mixed at 120°C for 4 minutes. 4 parts of benzoyl peroxide and 2.5 parts of N-cyclohexyl-2-benzothiazolesulfenamide were added and mixed at 115°C for 2 minutes. The belts were extruded at 80°C, placed on the inner and outer sides of a belt core for calendering, and then vulcanized on a flat vulcanizer at 150°C. The belts were molded in a herringbone pattern mold to obtain an upper convex herringbone pattern conveyor belt.

[0039] Comparative Example 1

[0040] The only difference from Example 1 is that ENR50 is not added.

[0041] After vulcanization of the cover rubbers obtained in Examples 1 to 7 and Comparative Example 1 on a flat vulcanizer at 150° C., the tensile strength was tested in accordance with GB / T 528-2009, and the wear volume was tested in accordance with GB / T 1689-2014. The test results are recorded in Table 1.

[0042] Table 1 Mechanical strength and wear resistance of covering rubber

[0043] Tensile strength / MPa <![CDATA[Wear volume / cm 3 > Example 1 26.9 0.069 Example 2 25.7 0.075 Example 3 27.6 0.063 Example 4 27.4 0.065 Example 5 27.3 0.066 Example 6 27.0 0.068 Example 7 27.9 0.060 Comparative Example 1 25.3 0.079

[0044] As can be seen from Table 1, the tensile strength of the cover rubber provided by the present invention is above 25.7 MPa, and the wear volume is 0.075 cm 3 Below, it has good mechanical strength and wear resistance.

[0045] Comparative Example 1 shows that ENR50 was added to Example 1 and not added to Example 1. The tensile strength of the cover rubber obtained in Example 1 was higher than that in Comparative Example 1, and the wear volume was lower than that in Comparative Example 1. This indicates that the addition of ENR50 can improve the compatibility between natural rubber and nitrile rubber, and enhance the mechanical strength and wear resistance of the cover rubber.

[0046] Compared with Examples 1 and 2, Example 3 adds ENR50 to Example 1, adds bis(2-hydroxyethyl)amino(trihydroxymethyl)methane to Example 2, and adds ENR50 and bis(2-hydroxyethyl)amino(trihydroxymethyl)methane to Example 3. The tensile strength of the cover rubber obtained in Example 3 is higher than that of Examples 1 and 2, and the wear volume is lower than that of Examples 1 and 2. This indicates that the addition of ENR50 and bis(2-hydroxyethyl)amino(trihydroxymethyl)methane is more effective in improving the compatibility between natural rubber and nitrile rubber than the addition of either ENR50 or bis(2-hydroxyethyl)amino(trihydroxymethyl)methane alone as a compatibilizer, and can significantly improve the mechanical strength and wear resistance of the cover rubber.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A conveyor belt with an upper convex herringbone pattern, comprising a belt core, an upper cover rubber layer provided on the outer side of the belt core, and a lower cover rubber layer provided on the inner side of the belt core, wherein the upper cover rubber layer and the lower cover rubber layer are independently composed of cover rubber, characterized in that: The covering rubber comprises the following components in parts by mass: 60-80 parts of natural rubber, 20-40 parts of nitrile rubber, 30-50 parts of filler, 5-10 parts of compatibilizer, 1-3 parts of antioxidant, 2-4 parts of vulcanizer, and 0.5-2.5 parts of accelerator; The compatibilizer includes epoxidized natural rubber and bis(2-hydroxyethyl)amino(trimethylol)methane; The mass ratio of the epoxidized natural rubber to bis(2-hydroxyethyl)amino(trihydroxymethyl)methane is 5-7:1-3.

2. The conveyor belt with an upward convex herringbone pattern according to claim 1, characterized in that: The mass ratio of the epoxidized natural rubber to bis(2-hydroxyethyl)amino(trihydroxymethyl)methane is 3:

1.

3. A conveyor belt with an upward convex herringbone pattern according to any one of claims 1 to 2, characterized in that: The epoxidized natural rubber includes one or more of ENR25, ENR50 and ENR75.

4. The conveyor belt with an upward convex herringbone pattern according to claim 1, characterized in that: The filler includes one or more of carbon black and talc.

5. The conveyor belt with an upward convex herringbone pattern according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 4010NA, antioxidant 4020, and antioxidant RD.

6. The conveyor belt with an upward convex herringbone pattern according to claim 1, characterized in that: The vulcanizing agent includes one or more of sulfur and organic peroxides.

7. The conveyor belt with an upward convex herringbone pattern according to claim 1, characterized in that: The accelerator includes one or more of sulfenamides and thiurams.

8. The process for preparing a conveyor belt with an upward convex herringbone pattern according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, after masticating and banburying the natural rubber, epoxidized natural rubber and nitrile rubber, adding bis(2-hydroxyethyl)amino(trihydroxymethyl)methane, filler and antioxidant for primary mixing, adding vulcanizing agent and accelerator for secondary mixing, and extruding to obtain covering rubber; S2. Place the covering rubber on the inner and outer sides of the belt core respectively, perform vulcanization, and form the belt to obtain a conveyor belt with an upward convex herringbone pattern.