What is the PFA

I. What is the PFA?

The English name of PFA is Polyfluoroalkoxy, or tetrafluoroethylene perfluoroalkoxyethylene ether copolymer (perfluoroalkylate, soluble polytetrafluoroethylene).PFA resin is relatively new fluoroplastic that can be processed by melting. PFA, FEP and PTFE have similar chemical properties, but FEP can only be used below 200 degrees, and PTFE cannot be injected. 【this resource was first published by China fluoroplastics network.】

1. Specific gravity: 2.13-2.167g/cubic centimeter

2. Molding shrinkage rate :3.1-7.7%

3. Molding temperature: 350-400℃

4. The melting point of PFA is about 580F and the density is 2.13-2.16g /cc (g/ cubic centimeter).

II. Features and main USES of PFA

PFA, commonly known as fusible PTFE, is the crown of fluoroplastics with various properties and USES similar to FEP.Widely used in semiconductor industry, as well as medical, chemical corrosion protection, automotive and other fields.

PFA products include granular products for molding and extrusion, and powdery products for rotating molding and coating.Its semi-finished products are membrane, plate, rod and pipe.PFA resin distributed in the American market includes Teflon of DUPOut, Neoflon of Daikin, Hthen of Ansimont and Hostafl of HOechst Celanese.

1. Main USES of PFA:

(1). Suitable for making corrosion resistant parts, wear - resistant parts, seals, insulation parts and medical equipment parts.

(2). High temperature wire, cable insulation layer, anti-corrosion equipment, sealing materials, pump valve bushing, and chemical containers.

2. Molding performance

(1). Crystallization material, small moisture absorption.Products may be processed by the usual thermoplastic processing method.

(2). Poor liquidity, easy decomposition, decomposition produced corrosion gas.It is advisable to strictly control the molding temperature not to exceed 475 degrees, the mold should be heated to 150-200 degrees, the pouring system should have little resistance to the material flow.

(3). Translucent granule, injection molding, extrusion molding.Forming temperature 350-400 degrees, 475 degrees above easy to cause color or bubble.And notice that it's harder to get out of the mold.

(4). Because the molten material on the metal corrosion effect, long-term production, the mold needs to electroplate chromium treatment.

3. Material performance

1. PFA is a copolymer of a small amount of perfluoropropyl perfluoroethylene ether and polytetrafluoroethylene.The melt bond is increased, the solution viscosity is decreased, and the performance is not changed compared with ptfe.The resin can be processed into products directly by ordinary thermoplastic molding.

2, long-term use temperature -80- 260 degrees, excellent chemical corrosion resistance, corrosion resistance to all chemicals, friction coefficient in the lowest plastic, and very good electrical performance, its electrical insulation is not affected by temperature, "plastic king" said.

3. Its chemical resistance is similar to ptfe and better than vinylidene fluoride.

4. Its creep resistance and compression strength are better than ptfe, with high tensile strength and elongation up to 100-300%.Good dielectric property, excellent radiation resistance.

5, non-toxic: with physiological inertia, can be implanted in the human body.

Explanation of main test indicators of PTFE products

PTFE products are a special type of plastic, which is quite different from other plastics. According to the industry standard of the Ministry of Light Industry, the PTFE products produced must meet the requirements of the index. Below we list the definitions of the 13 main test indicators for PTFE products for reference.

1. The coefficient of linear expansion indicates the degree of expansion or contraction of the material. It refers to the expansion ratio of the finished polytetrafluoroethylene plastic at a temperature of 1 ° C under a certain pressure, expressed as the coefficient of linear expansion relative to the unit length. This coefficient is one of the important indicators for understanding the degree of change in product size with increasing temperature of PTFE products, expressed in units of 1/°C or 1/K. The coefficient of linear expansion coefficient is α = ΔL / (L * ΔT), where ΔL is the change in the length of the object at the given temperature change ΔT, and L is the initial length. The linear expansion coefficient of PTFE is about 10-12*10-5/°C (ambient temperature 25-250°C), ie (0.01-0.012)%, and the linear expansion coefficient of PTFE is 10~20 times that of iron, which is larger than most plastics. 

2. Thermal conductivity: Also called thermal conductivity, it reflects the thermal conductivity of the material. It is defined as two parallel planes with an area of ​​1 m2 perpendicular to the direction of heat conduction inside the object. If the temperatures of the two planes differ by 1 K, the heat is transferred from one plane to the other in 1 second. The unit is defined as the thermal conductivity of the substance, and its unit is watt·m-1·open-1 (W·m-1·K-1). It is a reference indicator for studying the thermal insulation of target products when designing products.

3. The tensile strain at break is the tensile strain corresponding to the tensile fracture stress when the sample of the polytetrafluoroethylene product is not fractured under the tensile load, and the tensile strain is just when the sample material is plastically shaped. The ratio of the difference between the length to the original length and the original length, expressed as a percentage (%).

4. Tensile strength: In the test of tensile specimens, the critical value of the transition from uniform plastic deformation to local concentrated plastic deformation, characterizing the resistance of the material to the maximum uniform plastic deformation, is also the maximum load carrying capacity of plastic under static tensile conditions ( Maximum tensile stress). The unit is MPa. 

5. Elongation at break: It is the increment of the index from the original unit length (ie the rate of change of length), which is the ratio of the difference between the length of the pull-off and the original length to the original length, expressed as a percentage (%).

6. Electrical strength: A parameter indicating the breakdown of equipment insulation at a certain rated voltage, indicating the degree of insulation of the product withstand voltage. It means that under certain conditions, the ratio of the breakdown voltage to the thickness of the sample to be broken is the electrical strength of the product.

7. Breakdown voltage: The voltage at which the test piece breaks down is the highest voltage before being penetrated. That is, the sample does not break down at this voltage. The breakdown is usually caused by a partial discharge in the gas or liquid medium surrounding the sample and the electrode, and the sample at the edge of the smaller electrode (or equal-diameter two electrodes) is destroyed.

8. Density The ratio of the mass of a substance to its volume, that is, the mass of a substance per unit volume, is called the density of this substance. Kilograms/meter 3 or 1 gram per cubic centimeter 1.0 x 103 kg/m3 of polytetrafluoroethylene plastic products are usually tested by dipping, liquid pycnometer and titration.

9. Withstand voltage is the sample between the electrodes, the power frequency AC voltage rises to the voltage before the breakdown is the withstand voltage of the sample.

10. Fracture Nominal strain refers to the tensile strain corresponding to the fracture stress when the tensile specimen is not yielded and the fracture specimen is subjected to the specified specimen size, and the % is expressed by a dimensionless ratio or percentage.

11. The longitudinal dimensional change rate means that the pipe (100 ± 1) with a certain length is placed in a (260 ± 2 ° C) oven for 3 hours, and taken out at a normal temperature of 23 ± 2 ° C for 4 hours. The length of the treated sample is The percentage of the difference between the original size and the original size.

12. Dielectric strength is a measure of the electrical strength of a material as an insulator. It is defined as the maximum voltage per unit thickness that a unit is subjected to when it is broken down, in volts per unit thickness. The ratio of breakdown voltage to sample thickness. The breakdown voltage is tested according to GB/T1408.1-2006. The dielectric strength is in kilovolts per millimeter (KV/mm).

Introduction to seal gasket

With the advent of mechanization era, a variety of machinery and equipment emerge in endlessly, in a variety of mechanical equipment, sealing gaskets become unnecessary parts, is the industrial production enterprises and related industries to solve the gas, liquid medium "run, run, drip, leakage", root cure leakage effective tools.

As the name suggests, the seal gasket is a seal, mainly play the role of sealing, it is generally used for machinery, equipment, pipelines and other places where there is a fluid through.Used for connection between pipes or parts of equipment.

Popular at present, the market of sealing gaskets are metal or nonmetal after cutting, stamping or tailor made after processing, such as the common have high pressure asbestos rubber gasket, oil resistant rubber gasket, cylinder gasket, aramid fiber gasket, asbestos gasket, asbestos gasket, rubber mat and so on seven big classes, different material sealing gasket its specific applicable environment is different also, if the gasket failure, not only affects the operation of equipment, sometimes even cause an accident, a threat to the personal and property of people.

Relevant data shows that different gaskets have their national standards are different, in quality, density, corrosion resistance, lubricity resistance, oxidation resistance and other aspects of strict requirements, as long as all the parameters to achieve national standards, before entering the market.

Sealing gasket is commonly used in ptfe gasket, with good flexibility, compression resilience, creep resistance, high and low temperature resistance and excellent corrosion resistance, aging resistance, self-lubrication.With its very low leakage rate and excellent heat resistance and radiation resistance, and at the same time very convenient installation and use, is the chemical industry, medicine, petrochemical, food and beverage, electronics, power, metallurgy, shipping and other industries extremely ideal sealing material.

Teflon Lining Machine

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Advantages:

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PTFE Extrusion Equipment

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PTFE Tube Extruder Features:Vertical Ram Extruder for PTFE tube;Ram extruding machine for PTFE tube;Using for Pre-sintering PTFE material;Suit for new PTFE material or Recycle PTFE material;Rangeof diameter PTFE Extrusion 20-600 mm, Heating zones 5 zones; Automatic

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