Rubber processing aids are mainly used to improve the processing performance and physical properties of rubber compounding, calendering, extrusion, molding, etc., including dispersants, flow agents, homogenizers, viscosity enhancers, etc. EPDM rubber is a non-polar rubber, and the affinity among the compound and polar rubber is small, so when using EPDM rubber, EPDM recycled rubber, EPDM rubber/recycled rubber and rubber to produce rubber products, it is necessary to choose the appropriate variety of processing aids according to the actual needs to further reduce the cost of raw materials and improve the processing process performance and finished product performance.
1. Fatty acid rubber additives
Fatty acid rubber additives are one of the most commonly used processing aids in the production of EPDM rubber, EPDM recycled rubber and their combined rubber products, especially stearic acid: stearic acid can not only be used as an active agent in EPDM compounds, but also improve dispersion, prevent adhesive sticking to rollers, and improve release properties; When EPDM compounds contain impurities, stearic acid can also reduce the interfacial tension of the filler, destroy the agglomeration structure of the filler, and further improve the uniformity and stability of the compound.
2. Low molecular weight polymers
Polyethylene wax in low molecular weight polymers is widely used in the production of EPDM rubber and EPDM recycled rubber products. Polyethylene wax is a by-product of polyethylene synthesis, with low melting point and low melt viscosity, good compatibility with EPDM, and has a good internal lubrication effect and surface lubrication effect during processing, which can reduce the viscosity of the compound and improve the dispersion of the compound, and improve the mixing, calendering, extrusion and release properties of the compound, and the dosage is generally among 2-5 parts.
Hydrogenated liquid isoprene rubber, liquid EPDM rubber, polyisobutene and other low molecular weight polymers have good aging resistance and good compatibility with EPDM rubber, which can not only replace E5LYY826 paraffin oil as a low-volatility softener, improve the processing performance of EPDM compounds, but also improve the surface smoothness of EPDM products or the adhesion of semi-finished products. Generally, the dosage as a softener is about 10-25 parts, and the dosage as a processing aid is about 5-10 parts.
3. Wax rubber processing aids
Wax rubber processing aids are mainly used as external lubricants in the production of EPDM rubber and EPDM recycled rubber products. Ordinary paraffin wax can reduce the viscosity and metal adhesion of the compound, and the dosage in EPDM recycled adhesive is controlled within 1.5 parts to avoid frost spraying. Microcrystalline wax can effectively reduce the risk of frost spraying due to the controllable content of linear hydrocarbons, higher melting point and weaker migration, and is more suitable for the processing of high-quality EPDM rubber and recycled rubber products.
4. Polyethylene glycol
Polyethylene glycol is a multi-functional rubber processing aid, which can not only be used as a vulcanization activator and silica surface treatment agent in EPDM compounds, but also can improve the fluidity of EPDM rubber and EPDM recycled rubber, improve the appearance and release of products, and the dosage in the formulation of EPDM recycled rubber is 1.5-3 parts in the formula of EPDM recycled rubber extruded and injection molding.
5. Viscosity enhancer
EPDM rubber, EPDM recycled rubber or EPDM rubber/recycled rubber combined with adhesive to produce rubber products that need to be bonded with fabrics and metals, tackifiers are essential, thermoplastic phenolic resin ratio is common, the viscosity effect is better, the general dosage is 2-5 parts; The viscosity effect of m-tolucarbon-formaldehyde system is more effective, and the most used system is the system with the combination of viscosity enhancer RS and viscosity enhancer RH, usually 2-3 parts and 1-2 parts respectively, if it is used in combination with silica, the viscosity effect will be better.
6. Other processing aids
Rubber processing aids such as petroleum resin and coumalone resin can promote the dispersion and bonding of different rubber phases (such as EPDM and polar rubber), and the dosage is 2-5 parts in the combined system of EPDM recycled rubber, which can effectively improve the dimensional stability and physical properties of the product. Phenolic resin tackifiers can enhance the bonding strength of EPDM recycled adhesives with fabrics and metals, usually in 2-5 parts, which is a key additive for composite structural products.
When using EPDM rubber, EPDM recycled rubber or EPDM rubber/EPDM recycled rubber and using glue to produce different varieties of rubber products, it is necessary to choose the appropriate processing additives according to the processing needs to further reduce production costs and improve the yield.
Exclusive original article [commercial authorization] reprint, excerpt and excerpt in any form are prohibited without written authorization. Focus on Hongyun rubber: learn the process formula and raw material technology of producing rubber products from recycled rubber to help you reduce costs and increase profits