The recycled rubber processed by crushing, heating, mechanical and chemical treatment and other physical and chemical processes has a certain plasticity and viscosity, and can be reprocessed and re-vulcanized, which can replace high-priced natural rubber and synthetic rubber to produce various rubber products, effectively reducing the cost of raw materials, rubber sealing ring is one of them. So which recycled rubber can produce rubber seals? What issues should be paid attention to when choosing recycled rubber for rubber seals?
1. Definition and performance requirements of rubber sealing rings
Rubber sealing ring is a sealing element processed from rubber as the main material for various mechanical equipment, the main function is to prevent fluid or solid particles from leaking from adjacent bonding surfaces, and prevent external impurities from invading the equipment or system. The materials used in seals need to meet the following requirements.
(1) The material is dense and not easy to leak the working medium. (2) It has good adaptability and stability to the working medium. (3) It has appropriate mechanical strength and hardness, and is less affected by the working medium. (4) Good compressibility and recovery, small permanent deformation. (5) Good temperature adaptability to meet the working temperature requirements, such as no softening or decomposition at high temperature; It does not harden or crack at low temperature. (6) Small friction coefficient and good wear resistance. (7) Good corrosion resistance, can work in the working medium for a long time, and its volume and hardness change small. (8) Good softness and elasticity for adhesion to the sealing surface. (9) Good ozone resistance and aging resistance, long service life. (10) Good processing performance and low price. Recycled rubber has good elasticity and mechanical strength, and can be used in the production of rubber sealing rings, effectively reducing the cost of raw materials.
2. Commonly used recycled rubber varieties and characteristics of rubber sealing rings
(1) EPDM recycled glue
EPDM recycled rubber is processed from EPDM head adhesive, unvulcanized EPDM rubber and waste EPDM rubber products such as sealing strips as raw materials, which has good high and low temperature resistance, ozone resistance and weather resistance, and is an ideal raw material for the production of rubber sealing rings. Compared with EPDM raw rubber, EPDM recycled rubber has good processing performance and better compatibility with other rubbers, and can not only be used with EPDM raw rubber to produce rubber sealing rings, but also with butyl rubber, butyl recycled rubber, etc.
(2) Nitrile recycled rubber
Nitrile recycled rubber is processed from waste nitrile rubber and its products as raw materials, with excellent oil resistance, good wear resistance, heat resistance, and a certain mechanical strength, which can be used alone or in combination with nitrile rubber E5LYY95 and neoprene to produce oil-resistant rubber sealing rings, effectively reducing the cost of raw materials. The acrylonitrile content of nitrile recycled rubber directly affects the oil resistance of rubber sealing rings, and considering the oil resistance and price of recycled rubber, nitrile recycled rubber with acrylonitrile content of 36%-42% is more cost-effective.
(3) Other recycled rubber
Butyl recycled rubber has the characteristics of good air tightness, heat resistance, chemical corrosion resistance, etc., latex recycled rubber has good feel elasticity, high mechanical strength, and low price of tire recycled rubber products, which can be used in the production of rubber sealing rings, effectively reducing the cost of raw materials under the premise of ensuring the performance of rubber sealing rings.
3. Optiontion skills for recycled rubber for rubber sealing rings
(1) Determine the variety of recycled rubber
When using recycled rubber in rubber sealing rings to reduce costs, first of all, it is necessary to determine the variety of recycled rubber according to the use of rubber sealing rings, generally for rubber seals with high ozone resistance and weather resistance requirements to choose EPDM recycled rubber, oil-resistant rubber sealing rings use nitrile recycled rubber, general rubber sealing rings can be determined according to the cost budget whether to use tire recycled rubber or latex recycled rubber.
(2) Judge the quality of recycled glue
① The higher the rubber hydrocarbon content, the better the strength, elasticity and aging resistance.
② Mooney recycled rubber with a viscosity of 40-70 is more suitable for the production of rubber seals; Recycled rubber with too high viscosity makes it difficult to mix and has poor fluidity, and if the viscosity of Mooney is too low, the strength is insufficient and easy to deform.
③ The fineness of recycled rubber is greater than 60 mesh, with few impurities, smooth surface, no bubbles, and the rubber sealing ring produced is stable in size, flat in appearance, and has a higher yield.
④ The appearance of recycled rubber is uniform in color, the surface is fine, there are no hard lumps, no impurities, and no bubbles.
⑤ According to the requirements of the physical properties of the rubber sealing ring, choose a recycled rubber with tensile strength and tear elongation that is close to the requirements of the sealing ring.
⑥ Rubber sealing rings with environmental protection and odorless requirements need to use environmentally friendly recycled rubber and odorless recycled rubber.
When choosing recycled rubber for rubber sealing rings, a small batch of recycled rubber can be thinned out on the refinery, easy to wrap rollers, no rollers, no sticky rollers, and uniform mixing, proving that the processability of recycled rubber is good. It is difficult to wrap the roll, remove the roll, stick the roll, and mix unevenly, and the viscosity of the recycled rubber Mooney is abnormal and the regeneration is insufficient.
When using recycled rubber to reduce the production cost of rubber seals, rubber product manufacturers must choose the appropriate recycled rubber products according to actual needs, reasonably determine the mixing ratio of recycled rubber, and later share with you the key points of EPDM recycled rubber, EPDM rubber/EPDM recycled rubber and rubber sealing ring formula design and production process with glue.
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