Characteristics of conveyor belt materials

The rubber materials used in various parts of ordinary conveyor belts include covering rubber, buffer rubber, cloth layer rubbing rubber, and cloth layer adhesive rubber.
1. Covering rubber
When in use, it is subject to impact, wear and microbial erosion of materials, as well as various aging effects. Therefore, the covering rubber is required to have good tensile strength (≥18Mpa) and wear resistance (wear loss ≤0.8cm3/1.61Km), aging resistance, and biological erosion resistance. In addition, it is also required to have good process properties such as viscosity. The key points of formula design are as follows: Rubber Technology Network Raw rubber is mainly natural rubber or a proper amount of styrene-butadiene rubber.
2. Buffer rubber
The buffer rubber is between the covering rubber and the belt core layer, which can increase the adhesion between the two, and can absorb and disperse the impact of the conveying material, playing a buffering role. The rubber material is required to have good adhesion (adhesion between rubber and cloth ≥3.15N/mm), high elasticity, low heat generation, good heat dissipation, and good process performance.
3. Rubbing rubber
The main function of rubbing rubber is to bond the canvas layer of the belt core into a whole. It is required to have good adhesion to the core material (the adhesion strength between the cloths is not less than 4.5N/mm), fatigue resistance (the number of flexion times of the cloth layer is ≥25,000 times/full peeling), and sufficient plasticity (plasticity 0.5~0.6) and anti-scorching and other process properties.
4. The raw rubber is mainly natural rubber, and 20~30 parts by mass of styrene-butadiene rubber is used, with a rubber content of about 50%. The vulcanization system is the same as the general sulfur and accelerator system. The accelerator generally uses M and DM together, or adds a small amount of TMTD to speed up the vulcanization speed, but care should be taken to prevent the rubber from scorching. Carbon black should be semi-reinforced carbon black or other soft carbon black, with an amount of about 10 parts by mass. The amount of coumarone resin and petroleum resin should be appropriately increased for the rubbing rubber mixed with styrene-butadiene rubber, otherwise the adhesion of the cloth layer will be reduced.
Selection and marking of commonly used rubber conveyor belt materials
The rubber belt industry standard needs to involve the following definitions, which users can use as preliminary professional knowledge. The content is summarized as follows: Compression strength: the maximum compression stress that the sample can withstand in the compression test;
Melt flow rate: the amount of thermoplastic material extruded within a certain period of time under specified test conditions;
Elastic modulus: the ratio of stress to the corresponding strain of the material within the proportional limit;
Plastic: a material with polymer as the main component and can flow and form at a certain stage of processing into a finished product;
Rubber: an elastic material that can be modified or has been modified to be insoluble but swellable in boiling solvents such as benzene, methyl ethyl ketone and ethanol toluene azeotrope A modified rubber that is not easily remolded under heating and moderate pressure. Without diluent, it can shrink to less than 1.5 times its original length within 1 minute after being stretched to twice its length at standard room temperature and held for 1 minute and then relaxed;
Curing temperature: the temperature at which the adhesive or adhesive in the assembly is cured;
Curing time Adhesive: the time required for the adhesive in the assembly to cure under specified temperature or pressure or both;
Curing time Plastic: the time it takes for the plastic to fully harden;
Solid content: the mass percentage of non-volatile matter measured under specified test conditions;
Tensile strength: the maximum stress that a material can withstand before it breaks. When the maximum stress occurs at the yield point, it is called yield tensile strength. When the maximum stress occurs at the break, it is called yield tensile strength. , called tensile strength at break;
Viscosity: the performance of the fluid's internal resistance to stable flow. In the test, it is the ratio of the liquid's shear stress to the shear rate. Viscosity usually refers to "Newtonian viscosity". At this time, the ratio of shear stress to shear strain is a constant;
After the above explanation of the terminology, we can elaborate on the general provisions of the selection and marking method. When marking plastics, the name, brand abbreviation code, relevant instructions or performance index code, and standard number should generally be indicated; if there is no brand or code, only its name and standard number are marked. When there is no relevant standard, only the material name or commercial brand can be marked. At this time, the performance indicators of the material should be clearly specified in the product drawings or technical documents. In the plastic marking, if there is a brand, the name is uniformly marked with the word "plastic"; if If there is no brand name, the detailed name of the material should be written. In the marking, except for the name and the abbreviation code, all other components are connected with half-width connectors. The standard number is quoted according to the current valid standard, and only the standard code and standard sequence number are noted. The standard release year does not need to be noted. The standard code and standard sequence number are often separated by a space, that is, half a Chinese character. For example, when polyethylene PE is marked, the name, abbreviation code, recommended use and processing method code, relevant important performance and additive code, density, melt mass flow rate, and standard number should be indicated. When polypropylene (PP) is marked, the polymer type code, main use code, melt flow rate code, and standard number should also be indicated. The polymer type code is written after the abbreviation code. , with a connector in the middle;
In addition, in terms of synthetic rubber, its brand name is composed of a rubber variety code and four Arabic numerals. The first two digits of the four digits indicate the main characteristics of the rubber variety, and the last two digits are serial numbers arranged according to different properties such as filling conditions, Mooney viscosity or molecular weight. Rubber materials are marked with name, type, grade, basic physical properties, grade number, and standard number. The name is uniformly written as rubber. The marking of rubber sheets should indicate the product name rubber sheet, nominal thickness, technical feature code oil resistance, tensile strength, elongation at break, nominal hardness, heat resistance, low temperature resistance and other indicators, standard number, etc. If there is no relevant standard, the performance indicators of the rubber sheet should be clearly specified in the product drawings or technical documents.