The rubber material using sulfur vulcanization has good physical and mechanical properties, and the combination with accelerator can promote sulfur activation, accelerate the cross-linking reaction among sulfur and rubber molecules, shorten the vulcanization time and reduce the vulcanization temperature. When using nitrile recycled rubber as the main raw material to produce rubber products, sulfur is the most commonly used vulcanizing agent, how much sulfur is appropriate? Which accelerator is more suitable for the sulfur-accelerator system of nitrile recycled rubber products?
1. The amount of sulfur in the sulfur-accelerator system of nitrile recycled glue
When the rubber products produced by nitrile rubber, nitrile recycled rubber or nitrile rubber/recycled rubber are vulcanized with sulfur, the amount of sulfur directly determines the cross-linking density and cross-linking bond type of the compound, and affects the hardness, strength, elasticity, heat resistance and compression set properties of the vulcanized rubber of nitrile recycled rubber.
The amount of sulfur in nitrile rubber products can be adjusted according to the acrylonitrile content of nitrile rubber, and the amount of sulfur in nitrile rubber and nitrile recycled rubber with high acrylonitrile content is less, in 1.5-2 parts; The amount of sulfur in nitrile rubber with low acrylonitrile E5LYY822 content can be appropriately increased. When producing hard rubber from nitrile rubber and nitrile recycled rubber, the amount of sulfur needs to be increased to 10-25 parts to achieve extremely high cross-linking density. When producing heat-resistant, low-compression permanent rubber products, the amount of sulfur is reduced to 0.1-0.5 parts.
2. Accelerator selection skills in the sulfur-accelerator system of nitrile recycled glue
When nitrile rubber and nitrile recycled rubber products are sulfur vulcanized, the commonly used accelerators are thiazoles, hyposulfonamides and autumn rams. When aldehyde amines and guanidine alkaline accelerators are used alone, they are easy to scorch and increase the compression deformation, which is not suitable for nitrile compounds.
(1) Select tetramethyl chiurum disulfide (TMTD) or chulam vulcanization accelerator with the same structure, and adopt low-sulfur or sulfur-free combinations, nitrile rubber, nitrile recycled rubber vulcanized rubber can obtain excellent thermal properties;
(2) The sulfurization system of tetramethyl churamm monosulfide (TS) and sulfur can make the NBR vulcanized rubber have low compression deformation and minimal scorching tendency.
(3) When choosing the vulcanization system of disulfide dibenzothiazole (DM) or N-cyclohexyl-2-benzothiazole hyposulfonamide (CZ) and sulfur, the vulcanization speed is faster, and the vulcanization glue of nitrile recycled rubber has good performance, which is a general vulcanization system.
(4) The combination of accelerator DM and aldehyde-amine condensate can improve the constant tensile strength, reduce elongation and permanent deformation of oil-resistant vulcanized glue, and have good heat aging resistance.
(5) In the vulcanization system, the combination of high amounts of autumn rams and hyposulfonamides, or the combination of autumn rams and thiazoles, can produce nitrile vulcanized glue with excellent physical and mechanical properties, good heat aging resistance and low compression deformation, and can reduce the scorching phenomenon and frost spraying of vulcanized glue.
When using nitrile rubber, nitrile recycled rubber and its combined rubber to produce rubber products, the vulcanization system must be reasonably selected. In actual production, nitrile recycled rubber can also use peroxide vulcanization, resin vulcanization or cadmium-magnesium vulcanization system, and continue to discuss related issues with you later.
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