PTFE is a fluorine-containing material with excellent comprehensive properties. With the continuous improvement of social demand, the market potential of this part of the product is huge.
Polytetrafluoroethylene (PTFE) has the reputation of “the king of plastics”. The excellent performance of polytetrafluoroethylene comes from its unique molecular structure. The structural formula of polytetrafluoroethylene molecule is [CF2CF2]n, and all the hydrogens connected to carbon atoms are replaced by fluorine atoms. Under the protection of fluorine atoms, polytetrafluoroethylene Ethylene has excellent temperature resistance, corrosion resistance, aging resistance, insulation, flame retardant, anti-sticking, self-lubricating and other properties, and has been widely used in many fields.
Using the excellent properties of PTFE to blend and modify engineering plastics can achieve complementary advantages, further improve the performance of engineering plastics, and expand its application fields. The modification of engineering plastics by polytetrafluoroethylene blend modifier mainly focuses on two aspects: anti-friction lubrication and anti-drip flame retardant.
1. Anti-friction lubricant
The surface friction coefficient of most engineering plastics is high, and external lubricants need to be used in sliding friction occasions, which limits the application of engineering plastics in occasions where external lubricants are not allowed. Polytetrafluoroethylene has low surface energy and excellent self-lubricating properties. By blending polytetrafluoroethylene with engineering plastics, oil-free lubricating composite materials with low surface friction coefficient can be prepared.
The PTFE anti-friction lubricant used for the modification of engineering plastics is a PTFE ultrafine powder with a molecular weight of 30,000 to 200,000 and an average particle size of less than 30 microns, also known as PTFE micropowder. The use temperature range, weather resistance, chemical stability, self-lubrication, non-stickiness and other properties of PTFE micropowder are exactly the same as those of high molecular weight PTFE resin. While maintaining the original performance, PTFE micropowder also has the advantages of good dispersibility, easy to mix with other materials evenly, etc. It is a modifier with excellent performance.
2. Anti-drip agent
With the continuous expansion of the application field of engineering plastics, its products are divided into three categories for PTFE anti-drip agents: pure powder type, emulsion type and core-shell type.
(1) Pure powder type
The pure powder type anti-drip agent is pure PTFE particles. By sintering the surface of the particles, the dispersibility and fluidity of PTFE can be improved. When the anti-drip agent is pre-mixed with plastic, it can express Better dispersion properties and avoid premature fibrillation.
The advantage of pure powder type anti-drip agent is that the content of PTFE is 100%, no other impurities are introduced, and a relatively large amount can be added.
(2) Emulsion type
Emulsion type anti-drip agent is to disperse polytetrafluoroethylene in water under the action of dispersant to make polytetrafluoroethylene dispersion emulsion. Because the emulsion contains a large amount of water, the equipment and technology are required to be higher in use. Affected by this, few domestic engineering plastics manufacturers use emulsion-type anti-drip agents.
(3) Core-shell type
The core-shell type anti-drip agent is coated with a layer of polymer on the outside of the PTFE particles, so that it has better dispersibility in the process of mixing with plastic resins. The outer covering shell polymers are typically polyacrylonitrile, polystyrene and polymethyl methacrylate.
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