PTFE Products - Teflon Gasket making process

mail: info@sukoptfe.com 

https://ptfe-machinery.com/ 

https://www.sukopolymer.com/ 

https://www.sukoplastic.com/

Best cutting solution for sealing PTFE gaskets

PTFE gaskets, also known as Teflon gaskets, are widely used as sealing and filling materials in petroleum, chemical, pharmaceutical, electric power, steel and other industries for their excellent material properties. And the great empowering values created by Teflon gaskets should not be underestimated. Today, let’s talk about knowledge about PTFE gaskets and PTFE gasket molding equipment.

Teflon gasket is a polymer compound made of tetrafluoroethylene by polymerization, which has excellent chemical stability, corrosion resistance, sealing, non-toxicity, high lubrication, non-adhesion, electrical insulation, age resistance, and many other excellent characteristics. Therefore, it has been widely used in various applications.

As one of the best corrosion resistant materials, PTFE gasket has solved many problems in the areas of chemical, petroleum and pharmaceutical. Meanwhile, it has a variety of applications as a sealing material. How to better cut and process PTFE to solve the problems of complicated punching operations, serious material wastes, low utilization rate and secondary grinding processing has become the key focus of many gasket manufacturers.

With the market becoming intelligent and mechanized, manual operation has been gradually replaced by machines, and laser machine, an insulation cutting machine, is not suitable for the cutting of all the materials, which will easily produce odor or material damage, thus reducing sales volume.

Highly efficient and accurate PTFE gasket automatic press molding machines are designed to improve production efficiency and product quality, and promote the green and sustainable development of the production chain. This kind of machine can meet customers’ needs and guarantee product quality in a more efficient and precise manner in the era of intelligent automation.

Established in 2006, Suko has over 13 years of manufacturing experience in PTFE/UHMWPE extrusion machinery and equipment for special applications in the field of plastics processing, and stays forefront of the Tetrafluorohydrazine industry with technology innovation, profession and intelligence both domestically and abroad.

Study on Sintering of Ptfe

From the perspective of the three factors that determine the properties of PTFE products -- molecular weight, crystallinity and voidage, the voidage is mainly affected by the preforming pressure, and the molecular weight and crystallinity all change with the different sintering conditions. Therefore, sintering process conditions play a decisive role in the final properties of products such as density, hardness, permeability and mechanical properties.

Wang ping found that the sintering process of PTFE was affected by the rising and falling speed, sintering temperature and sintering time. The larger the product, the slower the speed of rising and cooling, the longer the sintering time. The sintering temperature of suspension resin is higher than that of dispersion resin. The sintering temperature of pure material products is higher than that of filled products. In general, the rate of warming is faster than the rate of cooling. In the same sintering furnace, pure material and filling products cannot be mixed; Products with different sintering conditions cannot be mixed. Products of different raw materials cannot be mixed. Taking the production of 3-layer molded circular plate with diameter of 1 m, thickness of 20 mm, double layer as pure ptfe and middle layer as filled ptfe as an example, the compression strength, bending strength, hardness and other mechanical properties of the circular laminated plate produced by this technology have been greatly improved.

Liu xianlan studied the forming process characteristics, forming method and mold design characteristics of PTFE, analyzed the defects and causes of PTFE products produced by cold pressing and sintering, and put forward the treatment methods. PTFE can be molded by a variety of preforming processes, such as molding, extrusion, hydraulic molding, push molding and secondary processing, and then sintered to the final product.PTFE molding is mostly made of suspended resin. When the thickness of sheet is less than 1.5mm, disperse resin is used. Its technological process: resin - sieve (suspension resin after pounding, loose, and the 20 mesh mesh sieve) - press (PTFE powder loading the mould under pressure from 20 to 35 MPa, after press compaction forming) - sintering (in 370 ~ 380 "C temperature sintering in sintering furnace) - moulded products (under free state within the mold or after cooling to finalize the design as required by the board, rods, tubes, gaskets and packing products, etc.).Hydraulic method is also called the equilibrium method or rubber molding in its operating process is: put rubber bag in die - connected to the water pump, filling the water swell the rubber bag into a cylindrical - resin evenly join between bag and external mold mold closing - continue to gradually increase the water pressure, water filling up to 12 ~ 13 mpa pressure maintaining 30 min: after water - decompression, ripping, sintering, cooling is the use of bright and clean appearance. Push is also called the paste extrusion molding, 20 ~ 30 mesh sieve dispersion resin and organic liquid (such as toluene, petroleum ether, the solvent oil) mixture 1:5 paste mixture, preloading into thick wall cylinder billet, push into the compressor cylinder, heating, with a plunger push molding, after drying in the 360 ~ 380 ° C temperature sintering, after cooling products have strong push tube, rod, etc.Extrusion molding can be divided into two types: screw extrusion and plunger extrusion. The pre-sintered resin after crushing and sifted is added to the material cylinder. Through screw rotation or reciprocating push of plunger, the raw material is transported to the extruder at the same time of compaction.

Wang ping studied the forming process of PTFE foam material. Suspended polytetrafluoroethylene is used as raw material, and condensed cyclic aromatic hydrocarbons are selected as pore-forming agent. After mixing, preforming products are preformed and sintered. At the initial stage of sintering, drying process is adopted to make pore-forming agent escape, and then resintering stage is entered. Foam materials with different dielectric constants can be prepared in different proportions to meet various requirements.

Chen xu et al. conducted compression test and sintering test on PTFE, discussed the relationship between density, compression strength and compression modulus, and analyzed the compression strength of specimens under different sintering processes, and obtained more appropriate molding pressure and sintering process. The results showed that the compression strength of PTFE decreased with the increase of pressing pressure, and the compression modulus increased with the increase of pressing pressure. The molding pressure was 27.5mpa, sintering temperature was 380 C, and the insulation time was 4h.

In order to overcome the disadvantages of pure ptfe, such as poor abrasion resistance and large thermal expansion coefficient, Raytheon studied the bronze-filled particles in ptfe, and expanded the application scope of ptfe. The conventional warm pressing molding of ptfe is characterized by long cycle, poor performance, low dimensional accuracy and smoothness, while the warm pressing molding in this study has fewer working procedures, short cycle and significantly improved mechanical properties.

The molding process of the press automatic Moulding Machine

Is moulded plastic processing and molding the application in the city one of the oldest technology. It has a mature production technology, equipment and mold is simple, easy to forming large products, can use multiple modes to improve the production of small parts, etc, in machinery, electronics, transportation and daily life, and many other fields has been widely used.

The market will often see a lot of kinds of Press Moulding Machine, for example: Polymer/PTFE Bush press Automatic Moulding Machine, Polymer/PTFE Flange press Automatic Moulding Machine, Polymer/PTFE gasket automatic Moulding Machine, Semi-automatic Molding Machine and so on.

Molding is widely used in the following fields:

Electrical: insulator, switch box, electrical equipment housing, insulation tools, wiring board, etc.

Automobile: lamp shade, front and rear bumper, battery bracket, engine soundproof board, etc.

Railway: window frame of vehicle, toilet components, seats, table tops, siding and roof of carriage, etc.

Construction: water tank, bath products, door panels, purification tank, building template, etc.

Bathroom: bathtub, integral bathroom equipment, integrated wash basin, etc.

And other areas of industry and agriculture.

Molding technology is a method of putting quantitative molding materials (powder, granular or fibrous plastic) into the metal mold and forming products under the action of temperature and pressure. During the molding process, heat and pressure are required to melt (or plasticize) the molding material, fill the mold cavity with flow, and make the resin solidify. The principle is that the process of pressurizing, shaping and heating depends on the closure of the heated mold.

Moulding Machine technology is the oldest molding method in plastic processing technology. Because of its long history, the molding technology has been quite mature, at present in thermosetting plastics and some thermoplastic plastics (fluoroplastics, uhmwpe, polyimide, etc.) processing is still the most widely used and the main position of the molding method. Moulded thermosetting plastic, placed in the cavity of the thermosetting plastic under the action of heat, first changed from solid to melt, melt flow under pressure with the shape of the cavity and cavity has given, as the crosslinking reaction, resin molecular weight increased, the curing degree rise, moulding material viscosity increase gradually and becomes solid, finally becomes demoulding products. Thermoplastic plastic mold pressure, in the previous stage of the situation and thermosetting Plastic the same, but because there is no cross-linking reaction, so in the flow of full cavity, the mold must be cooled to make its molten plastic into a solid with a constant strength can be demodulated into products. Because thermoplastic plastic mold pressing mold needs to alternately heating and cooling, production cycle is long, so thermoplastic products generally choose injection molding method more economic, only in the mold larger plane of Plastic products or because of the flow of thermoplastic plastic injection molding method is difficult to use molding.

In the mold press material filled with the mold cavity flow process, not only the resin flow, the reinforcement material also to flow, so the mold press molding process molding pressure is higher than other process methods, belongs to the high pressure molding. Therefore, it needs not only the hydraulic press which can control the pressure, but also the high strength, high precision and high temperature resistant metal die.