To an outsider,the production of rubber sheet rolls may seem like a simple roll of dark material.But to insiders,it’s a complex process involving intricate details—from molecular structure to equipment parameters.From raw materials entering the factory to final packaging and shipment,a qualified rubber sheet must go through four major stages:mixing,calendering,vulcanization,and testing.
When raw rubber first arrives at the workshop,it is not yet in the”usable”state described by experienced workers.The rubber molecules are long and coiled,tangled together with poor fluidity.They must first be repeatedly rolled and sheared using open mills,shortening the molecular chains and making their structure more uniform under shear forces—a process known as”plasticizing.”Once properly plasticized,the rubber sheet feels soft to the touch and has a fine,matte surface.Next,the compound enters the internal mixer,where additives such as carbon black,light calcium carbonate,naphthenic oil,and zinc oxide are added sequentially according to the formula.Carbon black plays the most critical role—it acts like countless tiny rivets anchoring between rubber molecules,directly determining the final product’s wear resistance and tensile strength.During mixing,the compound temperature rises rapidly,typically maintained around 120°C.If too high,the compound risks scorching;if too low,the additives won’t disperse evenly.Skilled operators can judge whether the mix is ready simply by listening to changes in the motor sound of the internal mixer—when the sound becomes dull and muffled,it indicates that the compound has become compact and well-mixed,signaling completion of this stage.
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The mixed compound is then transferred hot to the calendering machine.This machine operates similarly to an old-fashioned dough roller,with two or three large rollers rotating toward each other,gradually compressing the rubber into uniformly thin sheets.The precise gap between the rollers determines the thickness tolerance of the final roll.Although the resulting rubber blank now has the shape of a sheet,its molecular structure remains linear—soft when heated,brittle when cooled—and lacks any practical use value.
It is vulcanization that gives rubber its true elasticity,wear resistance,and tensile strength.Under heat and pressure,sulfur forms a three-dimensional cross-linked network among the rubber polymer chains,transforming individual chains into a vast 3D mesh.The choice of vulcanizing equipment directly influences the final product form.Drum-type vulcanizers are the primary machines for continuous roll production,distinguished by their large-diameter heated steel drums.The rubber blank slowly passes over the drum surface while being pressed continuously by high-strength steel bands,undergoing continuous vulcanization under combined heat and pressure.Most rubber sheets ranging from 1 to 10 millimeters in thickness are processed this way.In the final step,inspection,approved rolls are wound onto cores,labeled,and packaged according to customer requirements.
There are no shortcuts in rubber sheet manufacturing—each stage demands patience and precision.What appears as a simple roll of rubber is actually the result of meticulous,day-in-day-out craftsmanship,from raw material to finished product.
Jingdong Rubber Co., Ltd. is a professional rubber sheet manufacturer, producing silicone rubber sheet, natural rubber sheet, fluorine rubber sheet, neoprene rubber sheet, insulating rubber sheet,EPDM rubber sheets, oil-resistant rubber sheets, anti-static rubber sheets, flame-retardant rubber sheets, conductive rubber sheets, anti-slip rubber sheets, and cowshed mats, etc. with over 40 years of industry experience, are popular both at home and abroad. If you need any of our products,please send emails to ventas@jingdongrubber.com.