The application of UHMWPE

The molecular chain length of UHMWPE is 10 ~ 20 times that of hdpe. The main advantages of longer molecular chains (higher molecular weight) give UHMWPE are toughness, wear resistance and resistance to stress cracking. Because it is a kind of polyethylene, UHMWPE also has lubricity, chemical resistance and general purpose HDPE excellent electrical properties.

Long molecular chains make materials difficult to process in common moulding and extrusion equipment. When heated above the melting point, UHMWPE becomes transparent but does not flow.Chemical and performance UHMWPE is produced by ziegler polymerization. The process requires a particularly high degree of purity, ethylene monomer impurity control in a few parts per million. The product is a white powder with a particle size similar to that of table salt.

UHMWPE is used for low speed bearing housing. Low friction coefficient is further reduced by adding siloxane, aluminum disulfide, graphite and special paraffin wax. In the food processing industry, UHMWPE self-lubricity, easy purification, low flavor gas/flavor transmission and boiling water resistance are used. Has met FDA and USDA requirements for use in food, water, and pharmaceutical industries. Some of the USES of UHMWPE are based on its noise absorption and shock absorption. If UHMWPE is needed, dye can be used for coloring, while pigments are slightly inferior. 

PTFE/Polymer/UHMWPE Tube Ram Extruder, PTFE/Polymer/UHMWPE Rad Ram Extruder, Gasket machine, Plastic Pipe machine, etc. These machines can be used to produce a variety of fields need some ptfe, polymer, ultra high molecular weight and other products.

UHMWPE may be used in a new generation of self-unloading ore carriers, railway wagons and large trucks due to its smooth, non-viscous and abrasion resistance. These properties make it also useful for agriculture and earth-moving machinery, with UHMWPE materials to protect steel. The combination of chemical resistance and surface smoothness has many applications. For food processing industry, UHMWPE is used as the surface material of meat cutting board. UHMWPE is used as contact surface and roller for processing food and medicine conveyors. It has the properties of self-lubricating, resistance to boiling water and resistance to chemical cleaner.

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.

Properties of PTFE

PTFE is ideal for performance due to unique properties. The molecular structure of PTFE is depicted in Fig. . The properties of PTFE widely spread in all the branches and being used for a variety of applications. Various properties of PTFE are represented in Fig. Reports on various properties of PTFE have been discussed in this topic.

Physical properties of PTFE

 Barrier properties

PTFE demonstrated superior hydrophobic nature due to the low surface energy. Wrinkled superhydrophobic surfaces, fabricated from two forms of PTFE exhibit the durable and excellent barrier properties as the roll-off angle of the surfaces tend to be very low. The contact angle for single-scale wrinkled PTFE and hierarchical wrinkled PTFE surface was measured at 163° and 172° that has been possessing higher magnitude. Surface modification of PTFE from hydrophobic to hydrophilic property was optimized by the addition of chemical agents amino (-NH₂), carboxyl (-COOH) and sulfonic acid (-SO₃H). On microfiltration analysis, membranes of PTFE adhered with hydrophilic agent’s shows good microfiltration property. The property of plasma modified PTFE is more effective in high-performance direct contact membrane distillation (DCMD). PTFE has been treated with a plasma to obtain pore on the surfaces. Surface morphology study reveals the appearance of parallel pore layers during plasma treatment. Plasma treatment deploys contact angle as a function of treatment time. The bipolar Argon plasma treatment of PTFE also supports the same as with plasma treatment there is an increase in surface free energy. Even though the low surface energy property of virgin PTFE is useful but somehow it is difficult to blend or grind with other polymers. In such a case, the modification of surface is achieved using high-energy irradiation which is in connection with degradation process. Further examination revealed that under irradiation, the PTFE compound has low molecular weight and lower hydrophobicity.

A work on extended PTFE tape demonstrated the increase in water contact angle in a feasible manner. PTFE was stretched using a mechanical device for different ratio of extension. It was portrayed that the increasing extension ratio significantly increases the water contact angle of the surface. The water-repellent property of the surface was mainly due to the decrease in the density of PTFE tape under stretching. More precisely the reason for higher contact angle was the alignment of PTFE microforms on the tape.

The composition of inorganic fullerene-like tungsten disulfide (IF-WS₂) nanoparticles and PTFE improved the hydrophobic property. The drastic change in surface roughness of IF-WS₂/PTFE was revealed by atomic force microscope (AFM) images. Such key factor was the reason for the increase in hydrophobicity. The different contact angles reported for PTFE and PTFE composites are graphically shown in Fig.

Tribological property of PTFE surface

Surface friction of PTFE

Extensive studies have been done on the friction property of PTFE because of interesting low friction coefficient. Friction occurs due to the relative motion of the surface. A virgin PTFE reveals the ultimate friction resistance property therefore optimized for different types of lubrication. As a function of glass fiber, carbon, and graphite loading, there has been a strong influence over friction properties. A wear mechanism was reported for metal precursor-based PTFE composites. Nano-sized PTFE particles were filled in nickel (Ni) and phosphorous (P) coatings. The work revealed the considerable change in friction coefficient (μ) of Ni-P/PTFE coatings when subjected to wear test. Comparatively, Ni-P/PTFE coating exhibited low wear resistance than Ni-P coating because of the presence of PTFE particles.

Surface wear of PTFE

Wear is the most important property of PTFE among surface properties. In general, wear is also associated with mechanical properties, the parameters of wear include weight load, velocity, temperature, contact area, and sliding distance. A familiar method known as Pin-on-Disc setup was used to analyze the wear behavior. This test showed that the friction coefficient for virgin PTFE decreased with the increase in loading of carbon and bronze, increased the wear resistance whereas the friction coefficient was affected slightly. PTFE with filler loadings was effectively have good wear resistance when bearing the weight load over the surface.

Surface lubrication of PTFE

The performance of PTFE as self-lubricant bearings was well known and often examined for its excellent sliding behavior. The mitigation of London dispersive forces in PTFE is due to the highly electronegative fluorine atoms. Furthermore, this property of PTFE was thoroughly examined to improve for high efficiency. In PTFE compound, the fluorine atoms are very close, forming a smooth and cylindrical surface so as the other molecules sliding over easily. In tribological view, PTFE is the topmost material preferred among all.

Abrasion property of PTFE

Abrasion property of PTFE interlinked with wear rate and friction coefficient. Pure PTFE compound are good in abrasion resistance but fixing it on the surface is the challenging task. Glass fiber (GF) and carbon fiber (CF) filled PTFE were tested for the abrasion resistance capacity. The abrasiveness and surface morphology of the worn surfaces of GF/PTFE and CF/PTFE was studied using scanning electron microscope (SEM). The wear volume was certainly lost in GF/PTFE than CF/PTFE. Under various weight loads, CF/PTFE poses better abrasion resistance because of the adhesion of carbon fibers with the PTFE matrix. Although PTFE possesses lower friction property than any other polymer, the addition of filler makes it suitable for interfacing with good friction resistance.

Mechanical properties of PTFE

Tensile, hardness, stress, and strain tests on PTFE

The mechanical property of PTFE deals with the study of tensile strength, stress and strain, ductility, hardness, and molding ability. PTFE is ductile in nature and obviously remains low in mechanical phase when compared to other polymers but PTFE has a good advantage in constructing mechanical device parts by loading filler components. Compression test on two grades of PTFE exhibited good mechanistic performance. Significantly the mechanical properties are affected by temperature hence the samples of PTFE were also tested with the load of 50% at a temperature varying from − 198 to 200 °C. During deformation, PTFE undergoes a structural change of approximately 30% in comparison with metals which are less than 10%. The rearrangement of molecules due to strain is temporary because of the viscoelastic nature of polymers and permanent damage when it reaches the physical aging.

Generally, the unfilled PTFE exhibits very poor flexural properties. An improvement over mechanical property has been studied in detail for the composite material Polyamide6 (PA6)/PTFE. Flexural and tensile properties test were conducted for different PA6 content. The samples were analyzed by keeping constant load for five specimens of different magnitudes and the morphology was observed using SEM. Under stress, the deformation of PTFE occurs and improves the flexural toughness due to the absorption of energy. Results showed that the 30% PA6-reinforced PTFE composites have a significant improvement in mechanical performance. The improved tensile strength of PTFE composites is depicted in Fig.

Improvement of mechanical property as a function of temperature

PTFE filled with expanded graphite nanoparticles (nano-EG) with reinforcement of nano-aluminum oxide_, nano-copper, nano-silicon dioxide were studied to explore its mechanical properties. Dynamic mechanical thermal analysis (DMTA) method was used to analyze the mechanical property. It is noteworthy that the composites reinforced with nano-materials have a remarkable improvement in strength and hardness in comparison with the pure PTFE. DMTA provided good results under testing of the composites and different types of reinforcement showed different distinct mechanical properties. Notably, the composite added with nano-Al₂O₃ showed higher tensile strength and the composite added with nano-SiO₂ showed high elastic modulus. Dynamic mechanical testing proved that the increase of hardness in PTFE/Nano-EG composites with an increase in stress relaxation time and limit.

Creep resistance properties of PTFE

Creep test is important for engineering polymers. Lower creep rate increases the ability of the material to withstand under harsh physical conditions. PTFE exhibits high creep and causes hindrance to utilize in applications. The improvement in creep properties of PTFE with the addition of micro and nanoscale fillers are an important case of study. Directional PTFE/nano-SiO₂ thin films were tested for the improved creep property. Epoxy based nano-SiO₂ mixed with powder PTFE before it is executed for sintering process. The addition of SiO₂nanoparticles increases the crystalline form of PTFE. Thermal mechanical analyzer (TMA) was used to analyze the mechanical properties of the composite. The tensile properties of PTFE and PTFE composites (nano-SiO₂) were measured and it shows the difference in modulus, tensile strength, and elongation at break at a different weight percent (wt.%) of PTFE/Nano-SiO₂. The results clearly indicate that the addition of nano-SiO₂ considerably improves the tensile strength and hardness and in particular, it reduces the creep strain and creeps rate. The reinforcement of short carbon fibers and short glass fibers significantly improved the tensile strength of 18 wt.% and 20 wt.% of the filler ratio to the PTFE which was reported by the authors.

Chemical properties of PTFE

The peculiar property of PTFE is chemical inertness. Naturally, PTFE is non-reactive and insoluble due to the strongly bonded carbon-fluorine atom. The high molecular weight is responsible for chemical inert behavior. PTFE is not affected by common reagents such as hydrofluoric, hydrochloric, and chlorosulfonic acids. Even above the transition temperature (327 °C), PTFE is insoluble in organic solvents like hydrocarbons, chlorinated hydrocarbons, or ester and phenol. This is due to the very fewer interaction forces between fluorocarbon and other molecules.

Solubility of PTFE

A detailed and comparative examination has been made on the solubility of PTFE under thermodynamic observations. The solvents chosen are oligomers, non-oligomeric perfluorocarbons, aromatic perfluorocarbons, and non-perfluorocarbons. The report was consolidated the different types of thermodynamic solubility influence on PTFE. The solubility of PTFE involves various factors such as temperature, pressure, solvent polarity and swelling in solvents.

There are many practical issues of PTFE in terms of solubility. Several methods were employed to understand the solubility of PTFE with commercial solvents such as perfluorocarbon and other halogenated fluids. Autogenous and superautogenous methods were involved in the solubility of PTFE under applied pressure. The report suggested that the entropy effects cause insolubility due to the less intermolecular forces. The molecular weight of the solvent can influence the solubility with the increase of lower critical solution temperature.

2.4 Thermal properties of PTFE

The performance in terms of thermal conductivity of PTFE over a wide range of temperature is excellent than other polymers. The thermal stability is due to the linear high crystalline arrangement of carbon-fluorine atoms that shows a high melting point of about 342 °C. For the measurement of crystallinity, different techniques can be preferred such as X-ray diffraction, density and dynamic mechanical analysis (DMA). The differential scanning calorimetry (DSC) technique was used to prepare the material from the melt with different crystallinity as a function of temperature. The sample was further tested with reference to one another. The thermal conductivity was measured using Lee’s disk apparatus clearly indicates the improvement in heat transport of aluminum flakes included PTFE. The increase in thermal conductivity at 232 °C was noted for different levels of crystallinity. A detailed study on the thermal behavior was carried out by incorporating ceramics (Sr₂ZnSi₂O₇) as a filler with PTFE. This work explains that how the filler fraction is responsible for the increase in thermal conductivity of the composites. It was measured that the thermal conductivity of Sr₂ZnSi₂O₇ is 16.5 W/mK which is large when compared with PTFE (0.283 W/mK). The increase in thermal conductivity depends upon the filler material’s shape, size, and thermal properties. The fillers generally provide the heat transfer path which was the reason for the increase in thermal conductivity.

2.4.1 Thermal transport property of PTFE composites

Thermal transport property of Al/PTFE nanocomposite with graphene and CNT were reported. Graphene and CNT are widely involving in numerous applications and significantly influence the material behavior which is added along with them. By introducing graphene into Al/PTFE, increasing thermal conductivity was observed. Al acts as a mediator for heat transportation throughout the composite. Thermal diffusivity analysis of Al/PTFE portrayed about how quickly the material responds to the heated environment. The addition of graphene in Al/PTFE increases thermal diffusivity in contrast to the addition of nano carbon (C) allotrope and CNT. The amorphous nature of nano C and CNT is due to the random arrangement of sp² and sp³carbons which results in low thermo-physical property.

2.5 Electrical properties of PTFE

2.5.1 Dielectric property of PTFE

PTFE would play a role of a dielectric medium or insulating medium in an electronic component was consumed potentially because of distinct electric properties. The dielectric constant (ɛ_r) and the dissipation factor (tanδ) are very important for a material operating as a dielectric medium in the charge storing devices. Recently, many works were explored the dielectric properties of PTFE-based composites. Depending upon the filler property, the ɛ_r and tanδ varied and demonstrated in many reports. The improved ɛ_r and tanδ for various PTFE-based composites are shown in Fig. . It shows the PTFE composites tested under different frequency ranges and their respective ɛ_r and tanδ values. It is obvious that depending upon the frequency, the polarization mechanism varies for different types of composites. For PTFE filled with SiO₂ (silicon dioxide), the values of ɛ_r and tanδ increased at 5GHZ of frequency when compared to Virgin-PTFE. The large surface area of the SiO₂ and their moisture absorbance and contaminants were taken into account for explaining the function of ɛ_r and tanδ. PTFE/AlN (aluminum nitrate) showing improved ɛ_r and tanδ as a function of filler loading. The values were obtained in the low frequency range from 100 Hz to 1 MHz which was suggested for electronic packaging. PTFE/TeO₂ showed excellent ɛ_r and tanδ stability tested under 1 MHz and 7 GHz of the frequency range. The increase in tanδ was observed due to the interfacial polarization of the ceramic TeO₂ particles at higher volume fraction in the PTFE matrix. The experimental results showed the improved dielectric constant of MgTiO₃ceramic filled PTFE. The results were good in agreement with the Maxwell-Garnett theoretical model which considers the occupation of ceramic particles in the host polymer system. The calcium copper titanate incorporated PTFE and its dielectric property was studied. The ɛ_rhere reported at low frequency (100 Hz) and attributed to interfacial polarization mechanism. The size of the particle present in the composites obviously changing the value of ɛ_r and tanδ which were demonstrated. Over different frequency ranges, PTFE is stable and possess low dielectric constant ɛ_r ∼ 2.1 and low loss tangent because of the neutralization of dipole moment exhibited by C-F bonds. A work was reported on the moisture absorbance of PTFE/Micron-rutile and PTFE/Nano-rutile composites. The moisture absorbing phenomena is important here because the water molecules are polar in nature having high ɛ_r ∼ 70 which can significantly affect the dielectric nature of the PTFE composition. It is to understand from the above notes that the filler compositions, the size of the particles, frequency, and property of the host polymer system are the important parameters for the dielectric properties.

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 Optical and spectral properties of PTFE

The inherent optical and spectral properties of PTFE greatly help in the instrumentation of efficient optical devices. The light reflectance and diffusion parameters of PTFE are extremely high; hence, the material has been inevitable in optical instrumentation. Reflectance factor is the measurement of the surface’s ability to reflect light which is equal to the ratio of reflected flux to the incident flux. PTFE exhibits good optical characteristics from a broad ultra-violet to near infra-red spectrum and good in performance when exposed to light or any other electromagnetic radiation. The reflectance angle measurements were studied using reflectometer which was used to measure the bidirectional reflectance of the PTFE pallet. The applications of PTFE as a light diffuser in radiometry were very attractive. The Lambertian surfaces (an ideal surface having high diffusive reflectance) are constructed with PTFE. Previous works considering that low density PTFE functions as a Lambertian diffuser. Measurement of bidirectional reflectance distribution function (BRDF), directional hemispherical reflectance (DHR) and directional hemispherical reflectance (DHT) were taken for two samples namely high density PTFE (HD PTFE) and low density PTFE (LD PTFE). To cover the entire wavelength of the spectrum, the aforesaid measurements were carefully done with the help of Fourier transform infrared Raman spectroscopy (FTIR) and LAMBDA 950 spectrophotometer. The results shown were in favor of LD PTFE because of the order of magnitude for DHR is less than HD PTFE.

The reflectance factor of PTFE is extreme to sustain at high intense electromagnetic radiation. For all optics-based instrumentation works, PTFE was suggested as a white light diffuser. A work was conducted to study the reflectance factor of pressed PTFE powder with a standard reflectance factor scale ratio (45°/0°). The sample was pressed and examined with 45°/0° reflectometer for wavelength varying from 380 to 770 nm. Analysis of samples was done by taking two variabilities: one is an operator (samples collected from 10 different laboratories) and another one is the material (various composition of PTFE). Final result evolved with the expanded uncertainty of 45°/0° reflectance factor due to material and operator variability.

Amorphous PTFE commercially known as Teflon®AF is having a glass-like transparency and possess good optical properties and highly preferred in optical devices. Teflon® AF is a copolymer of PDD and TFE. A detailed study was conducted to calculate the refractive index, extinction coefficient (k), the absorption coefficient (α) and optical absorbance (A) of three different grades of Teflon®AF. The purpose of this work was to compare all the three grades for their respective optical properties. The samples were analyzed using spectroscopic ellipsometer. Further results revealed that the optical characteristics varied for three different grades of Teflon®AF with respect to the TFE content.

Types of Plastic Blow and Injection Molding

Each plastic part requires a specific manufacturing process which can be significantly different from one product to another. Injection molding is used to manufacture solid components while blow molding is used to make plastic products with hollow areas, such as bottles and containers

Injection stretch blow molding combines the injection molding and blow molding processes.The plastic is first molded into a solid preform, to create a threaded bottle neck. Once the preform cools it is fed into a stretch blow mold machine. The preform is then reheated using an infrared heater and blown into a plastic bottle with forced compressed air.

The Injection Molding Process

Injection molding is used to manufacture higher volume quantities of plastic products ranging in size from large components to small components requiring micro-precision accuracy.

There are many types of manufacturing  methods categorized under injection molding, such as thermoplastic injection molding, over molding, insert molding, cold runner molding and hot runner molding.

Thermoplastic Injection Molding

Thermoplastic injection molding uses thermoplastic polymer, meaning it changes to a liquid state when heated. Unlike thermoset plastics that cool into permanent solid, thermoplastics can be remitted into a liquid after cooling into a solid.

Overmolding

Overmolding, or two shot molding, is a process that covers an injection mold over another substance, such as metal, to improve the performance or durability of a product. A rubber-like compound, called thermoplastic elastomer (TPE), is a commonly used overmold material. An example of a TPE overmold application is the handle grips on a toothbrush.  Overmolds can also be used to seal products with parts made from several injection molds.

Insert Molding

Like overmolding, insert molding is an injection moldingprocess that combines two or more components into a single finished product. Insert injection molding inserts a component into the injection mold cavity and plastic material is filled around the insert. Inserts can add strength to a product and eliminate the need for additional parts to reduce the product weight.

Cold Runner Injection Molding

Cold runner molds use a sprue to fill the runners that inject plastic resin into the mold cavity.  In 2 plate molds, the runner system and parts are attached, and an ejection system may be used to separate the pair from the mold.The cold runner can reduce waste by recycling and regrinding the material, but this can also increase the total cycle time. Cold runner systems can be used for a wide variety of polymers and can allow for easy color changes.

Hot Runner Molds

Hot runner molds use a manifold to heat melted plastic resin and then send the material through a gate to fill the mold cavity. The two main types of hot runner molds are externally heated and internally heated.  The externally heated molds can be used with polymer that is less sensitive to thermal variations while internally heated hot runner molds allow for better control of material flow.

Because  hot runner molding  does not require the use of runners, potential waste material is reduced and  the recycling and regrind and process of virgin plastic does not impact the total run cycle time.

The Blow Molding Process

During the blow molding process, the raw plastic material is shaped into a hollow tube with one open end called a parison. The parison is pressed into a cooled metal mold and compressed air is forced into the parison. When the formed plastic cools and hardens, the metal mold opens and expels the product.

Source:https://www.sukoptfe.com/types-of-plastic-blow-and-injection-molding

Extruder Machine for PTFE Liner

Teflon PTFE Lined Tube high viscosity in the gel state (it does not truly melt) prevents it from being processed conventionally in extruders or injection molding. PTFE tubing is therefore dry molded or extruded in hydraulic extruders with (paste extrusion) or without (ram extrusion) lubricants. Paste extrusion of PTFE yields flexible tubing. However, it occurs in a batch process and thus long continuous lengths are limited to the batch size, unlike the melt-processible fluoropolymers FEP, PFA and ETFE.

This PTFE liner Extruder is to extrude PTFE liner,It keeps stable ram speed and produces precise high quality PTFE liner products. with our original technology. The PTFE liner ram extruder series from Sunkoo is able to extrude tube which dia from 20- 150mm.

Advantages:

* Save time and money; * Advance designed; * High output; * Low energy consumption; * Long-life; * PC touch screen,extremely user-friendly operation; * The extrude PTFE tubes physical properties is stable and adjustable;

PTFE Extrusion and Sintering Equipment

Jiangsu Sunkoo Machine Tech Co., Ltd is a leading Manufacturer and exporter of PTFE & UHMWPE machines having rich experience of more than 12 years in China.
Main Machines: PTFE & UHMWPE Rod Ram Extruder, PTFE Tube Ram Extruder, PTFE Semi-Automatic press molding machine, PTFE Full Automatic press molding machine, PTFE Gasket Machine,Sintering equipment.

Pipe/Tube extrusion Machine Features:Highly innovative, Save time and money;Advance designed; High output;Low energy consumption;Long-life;Tube OD Size range:20-600 mm;Tube Production Per Hour in Kg:10-15;Length :Unlimited;Fully automated systems;Ram Machine ensures precision both in the pressing procedure and in the sinter zone;Temperature controls are also provided.
 
Rod extrusion Machine Features:Highly innovative;Save time and money;Intelligent and easy-to-use;Fully automatic systems;Rod Dia Range Min – Max Dia:4mm – 500 mm;Production Per Hour in Kg:7-10+;Long- life, with modern technology and optimized design;Ram Machine ensures precision both in the pressing procedure and in the sinter zone;Temperature controls are also provided.

Sintering Furnace Features:Sunkoo sintering Furnace deliver tight temperature control and temperature uniformity throughout the heated chamber providing an efficient and consistent sintering process from cycle to cycle. These ovens are commonly used in applications requiring a material to be formed without melting, such as: sintering a PTFE molded rods, sheets tubes etc. Details:https://www.sukoptfe.com/teflon-ptfe-sintering-furnace

Source:https://www.sukoptfe.com/ptfe-extrusion-and-sintering-equipment

A vertical extruder to produce plastic rods

Vertical Extruder Features:Save time and money;Intelligent and easy-to-use;Long- life, with modern technology and optimized design;Min - Max Dia:20-500mm;Production Per Hour:Extrusion at 9-18kg/h;Automatic;

Sunkoo Rod Extruder(Teflon PTFE Rod extrusion) is designed using latest technology, fully reliable and easy to operate for customers. Performance in terms of production and working hour capacity is competitive to other machines. Low maintenance is required , giving high production in market.

1.Horizontal Ram Extruder for PTFE rod

2.Ram extruding machine for PTFE rod

3.Using for Pre-sintering PTFE material.

4.Suit for new PTFE material or Recycle PTFE material.

Features:

1. Save time and money, good advantage price offer to customers.

2. Intelligent and easy-to-use operations.

3. Small workplace required due to its compact design and electricity saving machine.

4. Super quality output and the physical properties is adjustable.

5. Precise temperature control, reaches + -1 degree.

6. Long- life, with modern technology and optimized design.

Ram extrusion is a process enabling the continuous production and processing of  PTFE (Polytetrafluoroethylene). The basic material is PTFE powder. The powder is fed into a cylindrical extrusion pipe, compressed by means of a ram and at the same time, transported through the pipe, which is heated up to sintering temperature. 

Source:https://www.sukoptfe.com/a-vertical-extruder-to-produce-plastic-rods

Horizontal Extruder - Horizontal PTFE Extruder

Horizontal PTFE extruder gives our customers great flexibility while occupying a minimum amount of floor space.

Horizontal extruders are come in standard sizes of 25-Ton, 50-Ton, 75-Ton, and 100-Tons of thrust, with stroke lengths of 36", 54", 72", 108" and the World’s Longest Stroke Extruder. This allows productivity unmatched in the industry.  It gives the World's Highest yield per cycle and when combined with our other equipment, makes the perfect extruder for a wire line or tubing line.

Horizontal PTFE Extruder Advantages

* Long service life through solid workmanship and use of high quality componentes
* Low wall thickness tolerance through self-centering mandrel and special nozzle
* Additional heatable extrusion cylinder for better extrusion quality
* Measurement transducer like pressure, force and ram speed for permanent control of the extrusion process and extrusion speed
* Hydraulic closure with high closing force for quick loading of the extruder
* Quick loading with special loading carriage - also possible with several pre-forms, no manual touch
* Special pre-form press with pre-form preparation device for multiple loading of the loading carriage i.e. extruder
* Electrically adjustable mandrel
* Measuring and controlling system for constant extruder speed
* Controlling system for constant speed of the extrudate
* Low space requirement through vertical construction
* Front and back charger, vertical and horizontal possible with hydraulic and spindle drive (2 degrees of accuracy)
* Delivery of complete systems possible (PTFE processing, pre-form press, paste extruder oven, winding unit as well as convoluting machine)
* User-friendly and maintenance-free system
* Special drying and sintering oven with adjustable blind, thus a better temperature guidance within the two zones and avoidance of explosion hazard
* The paste extrusion systems are designed especially to costumers requests
* Automatic adjustment of the total system as well as recording of the formula
* Operating through touch screen and recording of the extrusion process parameters

Source:https://www.sukoptfe.com/horizontal-ptfe-extruder

Fish Feed Extrusion Process with Extruder Machine

The early-stage extrusion processing was mainly used in food processing industry. Since the nineteen fifties, America had started to use this technology for feed processing field, especially for processing pet food and pretreatment of feed ingredients. 

Till the nineteen eighties, it has become the fastest developing technique of feed processing industry in the world, and has started to be applied in each sphere of feeding stuff industry, widely used for dry pet foods, some applications for livestock feed and fish feed. With the unceasing development of technology and the continuous rising of people living standard, the growth of aquaculture must follow the principle of producing green food without pollution, bringing significant attention and lots of intensive study on aqua feed production technology. And there is a consensus that adopting extrusion process to make fish feed is the major means to ensure producing high quality and safe aquatic products for human health, which is also a trend for feed industry progress in the future.

Commercial fish feed extrusion process refers to cook the mixture of feed ingredients under high temperature, moisture and high pressure by means of fish feed extruder within short time, whereby the high temperature is a direct result of friction(dry extrusion) or preconditioning and steam injection (wet extrusion). As a technological treatment, extrusion can make it possible to process a variety of fish feed ingredients, such as soybean, corn, rice, peas and raw materials with high water content. According to the moisture content of raw materials treatment, fish feed extrusion process can be divided into two types — dry type extrusion and wet type extrusion.

Currently, the main extrusion equipment applied in aquatic feed production is single screw fish feed extruder which is also divided into dry type fish feed extruder and wet type fish feed extruder machine. With different parameters and feed formulation, fish farmers and feed plants can make floating, sinking and slow-sinking feed with high quality and nutrition so as to adapt for diverse ingestion requirements of various aquatic animals. Adopting alloy steel as material, FANWAY dry type fish feed extruder has been widely used in small-scale and medium-scale fish farm or feed plants to produce aqua feed and also dog/cat pet feed in virtue of its simple structure and low noise. Other than dry type, the wet type fish feed extruder machine is equipped with a boiler that can add vapor constantly into chamber when extruding feed ingredients, which makes it widely applied to produce floating fish feed pellets for fish farm, aquaculture and even poultry farms.

Source:https://www.sukoptfe.com/fish-feed-extrusion-process-with-extruder-machine