(acrylonitrile-butadiene-styrene)
English name: acrylic butadiene style
Specific gravity: 1.05g/cm3 molding shrinkage: 0.4-0.7% Molding temperature: 200-240℃ Drying condition: 80-90℃ for 2 hours.
The performance of this material is 1, with good comprehensive performance, high impact strength, good chemical stability and good electrical properties.
2. It has good weldability with 372 plexiglass, can be made into two-color plastic parts, and the surface can be chrome-plated and painted.
3, high impact resistance, high heat resistance, flame retardant, reinforced and transparent.
4. The fluidity is a little worse than HIPS, but better than PMMA and PC. And good flexibility. Suitable for manufacturing general mechanical parts, wear-resistant parts, transmission parts and telecom parts.
Plasticity 1. Amorphous materials with medium fluidity and high hygroscopicity must be fully dried. Plastic parts with glossy surface must be preheated and dried at 80-90 degrees for 3 hours.
2. It is advisable to adopt high feed temperature and high mold temperature, but it is easy to decompose when the feed temperature is too high (decomposition temperature > 270 degrees). For high-precision plastic parts, the mold temperature should be 50-60 degrees, and for high-gloss heat-resistant plastic parts, the mold temperature should be 60-80 degrees.
3. In order to solve the problem of water inclusion, it is necessary to improve the fluidity of materials and adopt methods such as high feed temperature, high mold temperature or changing water level.
4. If heat-resistant or flame-retardant materials are formed, after 3-7 days of production, plastic decomposition products will remain on the surface of the mold, resulting in the surface of the mold shining. The mold needs to be cleaned in time, and the exhaust position on the mold surface needs to be increased.
PS plastic
(polystyrene)
English name: polystyrene
Specific gravity: 1.05g/cm3 molding shrinkage: 0.6-0.8% Molding temperature: 170-250℃ Drying conditions:-
The material has excellent electrical insulation (especially high-frequency insulation), colorless and transparent, light transmittance is second only to plexiglass, good coloring, water resistance and chemical stability, and average strength, but it is fragile, prone to stress embrittlement, and resistant to organic solvents such as benzene and gasoline. Suitable for making insulating transparent parts, decorative parts, chemical instruments, optical instruments and other parts.
The formability is 1. Amorphous materials have small hygroscopicity, do not need to be fully dried and are not easy to decompose, but have large thermal expansion coefficient and are prone to internal stress. It has good fluidity and can be molded by screw or plunger injection molding machine.
2. It is advisable to adopt high material temperature, high mold temperature and low injection pressure, and prolonging injection time is beneficial to reduce internal stress and prevent shrinkage and deformation.
3. Various gates can be used, and the gates are connected with the plastic parts in an arc shape to avoid damaging the plastic parts when the gates are removed. The demoulding slope is large and the ejection is uniform. The wall thickness of plastic parts is uniform, and it is best not to have inserts. If there are inserts, preheat them.
PMMA plastic (plexiglass)
(polymethyl methacrylate)
English name: polymethyl methacrylate
Specific gravity: 1. 18g/cm3 molding shrinkage: 0.5-0.7% Molding temperature: 160-230℃ Drying conditions: 70-90℃ for 4 hours.
The material has excellent transparency, high strength, certain heat and cold resistance, corrosion resistance and good insulation, and its comprehensive performance exceeds that of polystyrene, but it is fragile and easily soluble in organic solvents. For example, as a light-transmitting material, its surface hardness is slightly lower and it is easy to scratch. Suitable for making transparent insulating parts and parts with average strength.
Moldability 1. Amorphous materials have high hygroscopicity, need to be dried, are not easy to decompose, have medium fluidity, and are prone to poor filling, mold sticking, shrinkage and weld marks.
2. It is advisable to inject at high pressure. In the absence of defects, high material temperature and high mold temperature are adopted to increase fluidity, reduce internal stress and improve transparency and strength. The surface of mold gating system should be smooth, with large demoulding slope and uniform ejection. At the same time, an exhaust port should be set to prevent foaming.
polyformaldehyde
(polyoxymethylene)
English name: polyformaldehyde
Specific gravity:1.41-1.43g/cm3 molding shrinkage: 1.2-3.0% molding temperature: 170-200℃ drying conditions: 80-90℃ for 2 hours.
The material has good comprehensive performance, high strength and rigidity, good wear resistance, low water absorption and good dimensional stability, but poor thermal stability, easy combustion and aging in the atmosphere. Suitable for manufacturing wear-resistant parts, transmission parts, chemicals, instruments and other parts.
The formability is 1. Crystallized materials have narrow melting range and fast melting and solidification, and crystallization occurs when the material temperature is slightly lower than the melting temperature. Medium liquidity. Low hygroscopicity, can be dried.
2. The friction coefficient is low, the elasticity is good, and the surface defects of plastic parts are prone to wrinkle patterns.
3. It is easy to decompose, and the decomposition temperature is 240 degrees. Irritant and corrosive gases will be produced during decomposition. Therefore, die steel should be made of corrosion-resistant materials.
PP plastic
(polypropylene)
English name: polypropylene
Specific gravity: 0.9-0.9 1g/cm3 molding shrinkage: 1.0-2.5% Molding temperature: 160-220℃ Drying conditions:-
The material has low performance density and better strength, stiffness, hardness and heat resistance than low-pressure polyethylene, and can be used at about 100 degree. Good electrical performance, high-frequency insulation, not affected by humidity, but brittle at low temperature, not mildew-proof, easy to age. Suitable for manufacturing general mechanical parts, corrosion-resistant parts and insulating parts.
Plasticity 1. Crystalline substance, low hygroscopicity, easy to melt and break, easy to decompose after long-term contact with hot metal.
2. The fluidity is good, but the shrinkage range and shrinkage value are large, which is prone to shrinkage cavity, dent and deformation.
3. The cooling speed is fast, and the pouring system and cooling system should slowly dissipate heat, and pay attention to controlling the molding temperature. In the direction of lower material temperature, the directionality is obvious, especially under low temperature and high pressure. When the mold temperature is lower than 50 degrees, the plastic parts are not smooth, and it is easy to produce poor welding and traces, and it is easy to warp and deform above 90 degrees.
4. The plastic wall thickness should be uniform, avoiding lack of glue and sharp corners and preventing stress concentration.
PE plastic
(polyethylene)
English name: polyethylene
Specific gravity: 0.94-0.96g/cm3 molding shrinkage: 1.5-3.6% Molding temperature: 140-220℃ Drying conditions:-
The material has excellent corrosion resistance, electrical insulation (especially high frequency insulation), can be modified by chlorination and irradiation, and can be reinforced by glass fiber. Low pressure polyethylene has high melting point, high rigidity, hardness and strength, low water absorption, good electrical properties and radiation resistance; High pressure polyethylene has good flexibility, elongation, impact strength and permeability; Ultra-high molecular weight polyethylene has high impact strength, fatigue resistance and wear resistance. Low-pressure polyethylene is suitable for manufacturing corrosion-resistant parts and insulating parts. High pressure polyethylene is suitable for making films, etc. Ultra-high molecular weight polyethylene is suitable for making shock absorption, wear resistance and transmission parts.
The formability is 1. Crystalline materials have low hygroscopicity and do not need to be fully dried. Its liquidity is very sensitive to pressure. High pressure injection molding should be used. Uniform material temperature, fast filling speed and sufficient pressure. The sprue is not suitable to prevent uneven shrinkage and increase internal stress. Pay attention to the selection of gate position to prevent shrinkage and deformation.
2. The shrinkage amplitude and shrinkage value are large, the directionality is obvious, and it is easy to deform and warp. The cooling speed should be slow, and the mold is equipped with a cold cavity and a cooling system.
3. The heating time should not be too long, otherwise it will decompose and burn.
4. When the soft plastic parts have shallow side grooves, they can be forcibly demoulded.
5. The melt may crack, so it is not suitable to contact with organic solvents to prevent cracking.
polyvinyl chloride
English name: Poly (vinyl chloride)
Specific gravity: 1.38g/cm3 molding shrinkage: 0.6- 1.5% Molding temperature: 160- 190℃ Drying conditions:-
The material has excellent mechanical and electrical properties, strong acid and alkali resistance, good chemical stability, but low softening point. Suitable for manufacturing thin plates, wire and cable insulation layers, seals, etc.
The formability is 1. Amorphous substances have low hygroscopicity and poor fluidity. In order to improve fluidity and prevent bubbles, plastics can be dried in advance. The gating system of the mold should be thick and short, the gate section should be large, and there should be no dead angle. The mold should be cooled and the surface should be chrome plated.
2. It is very easy to decompose, and it is easier to decompose when it contacts steel and copper at 200 degrees, and corrosive and irritating gases escape during decomposition. The molding temperature range is small.
3. When using the nozzle of the screw injection machine, the aperture should be large to prevent the dead angle from being delayed. If there is an insert, preheat it.
PA plastic (nylon)
(polyamide)
English name: polyamide
Specific gravity: PA6-1.14g/cm3 PA66-15g/cm3 PA10-1.05g/cm3 molding shrinkage: PA6-0.8-2.
The material is tough, wear-resistant, oil-resistant, water-resistant and enzyme-resistant, but it has high water absorption.
Nylon 6 has good elasticity, high impact strength and high water absorption.
Nylon 66 is superior to nylon 6 in performance, high strength and good wear resistance.
Nylon 6 10 is similar to nylon 66, but its water absorption and stiffness are low.
Nylon 10 10 is translucent, with low water absorption and good cold resistance, and is suitable for making general mechanical parts, wear-resistant parts, transmission parts, chemical, electrical and instrument parts.
The formability is 1. Crystalline materials have high melting point, narrow melting temperature range and poor thermal stability. When the material temperature exceeds 300 degrees, it will decompose if the residence time exceeds 30 minutes. It is easy to absorb moisture and needs to be dried, and the water content cannot exceed 0.3%.
2. Good liquidity and easy to overflow. Self-locking nozzles should be used and heated.
3. The molding shrinkage is large, the direction is obvious, and shrinkage cavity and deformation are easy to occur.
4. Mold temperature is selected within the range of 20-90 degrees according to the wall thickness of plastic parts, injection pressure is selected according to the type of injection molding machine, material temperature, shape and size of plastic parts, and mold gating system, and molding cycle is selected according to the wall thickness of plastic parts. When the viscosity of resin is small, the injection cooling time will be long, and white oil should be used as the release agent.
5. The form and size of mold gating system, and reduce shrinkage by increasing the size of runner and gate.
PC plastic
(polycarbonate)
English name: polycarbonate
Specific gravity:1.18-1.20g/cm3 molding shrinkage: 0.5-0.8% Molding temperature: 230-320℃ Drying conditions:10-/20℃ for 8 hours.
The material has high impact strength, good dimensional stability, colorless and transparent, good coloring, good electrical insulation, corrosion resistance and wear resistance, but poor self-lubrication, stress cracking tendency, easy hydrolysis at high temperature and poor compatibility with other resins. Suitable for making small instrument parts, insulating transparent parts and impact-resistant parts.
Moldability 1. Amorphous substance, good thermal stability, wide molding temperature range and poor fluidity. Small hygroscopicity, but sensitive to water, must be dried. Molding shrinkage is small and prone to melt cracking and stress concentration, so the molding conditions must be strictly controlled and the plastic parts must be annealed.
2. For plastic parts with high melting temperature, high viscosity and more than 200g, it is recommended to use a heated extension nozzle.
3. The cooling speed is fast, and the mold gating system is based on the principle of short thickness. It is advisable to set up a cold well, the gate should be large and the mold should be heated.
4. If the material temperature is too low, it will cause material shortage, plastic parts will be dull, and if the material temperature is too high, it will easily overflow and plastic parts will bubble. When the mold temperature is low, the shrinkage, elongation and impact strength are high, while the bending, compression and tensile strength are low. When the mold temperature exceeds 120℃, the plastic parts cool slowly and are easy to deform and stick to the mold.
Polyphenylene ether plastic
(polyphenylene ether)
Chinese name: polyphenylene ether
Specific gravity: 1.07g/cm3 molding shrinkage: 0.3-0.8% Molding temperature: 260-290℃ Drying conditions:130℃ for 4 hours.
The material performance is 1, which is white particles. It has good comprehensive performance, can be used in steam at 120℃, has good electrical insulation and low water absorption, but has a tendency to stress crack. Modified polyphenylene ether can eliminate stress cracking.
2. Excellent electrical insulation and water resistance, and good dimensional stability. Its dielectric properties rank first among plastics.
3.MPPO is a modified material made of PPO and HIPS*** (high impact polystyrene), and all the materials on the market at present are of this kind.
4. High heat resistance, glass transition temperature of 2 1 1 degree, melting point of 268 degrees, and easy to decompose when heated to 330 degrees. The higher the PPO content, the better the heat resistance, and the thermal deformation temperature can reach 190 degrees.
5, good flame retardancy, self-interest, and moderate flammability after mixing with HIPS. Light weight, non-toxic, and can be used in food and medicine industries. Poor light resistance, long-term use in the sun will change color.
6. It can be modified with ABS, HDPE, PPS, PA, HIPS and glass fiber. 1, suitable for making heat-resistant parts, insulation parts, wear-resistant parts, transmission parts, medical and electronic parts.
2. Parts that can be used at higher temperature, such as gears, blades and valves, can be replaced by stainless steel.
3, can make screws, fasteners and connectors.
4. Electrical parts of motors, rotors, housings and transformers.
Moldability 1. Amorphous substance, low hygroscopicity.
2. Poor fluidity, similar to Newtonian fluid, its viscosity is sensitive to temperature, the product thickness is generally above 0.8 mm ... It is easy to decompose, and corrosive gas is generated during decomposition. The molding temperature should be strictly controlled, the mold should be heated, and the resistance of the gating system to the material flow should be small.
3. The water absorption of polyphenylene ether is very low, about 0.06%, but a small amount of water will cause the surface of the product to be uneven, such as silver lines. It is best to dry it in the air, and the temperature should not be higher than 150 degrees, otherwise it will change color.
4. The molding temperature of polyphenylene ether is 280-330 degrees, and the molding temperature of modified polyphenylene ether is 260-285 degrees.
polysulfone
(polysulfone)
English name: polysulfone
Specific gravity: 1.25- 1.35g/cm3 molding shrinkage: 0.5-0.7% Molding temperature: 290-350℃ Drying conditions:130-150℃ for 4 hours.
materials performance
/use 1, polysulfone is amber transparent solid material with high hardness, high impact strength, non-toxic, good heat and cold resistance and aging resistance, and can be used for a long time at-100- 175 degrees. Resistant to corrosion of inorganic acids and alkali salts, but not resistant to aromatic hydrocarbons and halogenated hydrocarbons. Polyarylsulfone has high hardness, radiation resistance, good heat and cold resistance and self-interest, and can be used for a long time at-100- 175 degrees.
2. The reinforcement and modification of glass fiber can greatly improve the wear resistance of materials.
3. Polysulfone, ABS, polyimide, polyetheretherketone and fluoroplastics can all be made into modified products of polysulfone, mainly to improve its impact strength and elongation, solvent resistance, environmental resistance, processability and electroplating. Such as PSF/PBT, PSF/ABS, PSF+ mineral powder. 1, suitable for making heat-resistant parts, insulation parts, wear-resistant parts, instrument parts and medical equipment parts, and polyarylsulfone is suitable for making low-temperature working parts.
2. Polysulfone is often used to manufacture integrated circuit boards, coil formers, contactors, complete sets of frames, capacitor films and high-performance alkaline battery casings in electronic and electrical industries.
3. Polysulfone is used in household appliances, such as microwave oven equipment, coffee heaters, humidifiers, hair dryers, dryers, beverage and food dispensers. It can also replace non-ferrous metals for precision structural parts such as watches, copiers and cameras.
4. Polysulfone has passed the relevant specifications in American medicine and food field, and can replace stainless steel products. Polysulfone can be used as surgical tool tray, sprayer, fluid controller, heart valve, pacemaker, gas mask, denture and so on. Because it has the characteristics of steam resistance, hydrolysis resistance, non-toxicity, high temperature steam disinfection resistance, high transparency and good dimensional stability.
The formability is 1. Amorphous materials have high hygroscopicity, and the water absorption rate is 0.2%-0.4%. It must be fully dried before use to prevent moisture absorption again. Ensure that the water content is below 0. 1%.
2. Moldability is similar to that of PC, with poor thermal stability, and it begins to decompose at 360 degrees.
3. The fluidity is poor and the cooling is fast, so high temperature and high pressure molding should be adopted. The mold should have sufficient strength and rigidity, cold well and short runner, and the gate size should be 1/2- 1/3 of the wall thickness of plastic parts.
4. In order to reduce the internal stress of injection molded products, the mold temperature should be controlled at 100- 140 degrees. After molding, it can be annealed in glycerin bath 160 degrees, 1-5 minutes; Or air bath 160 degrees, 1-4 hours. The annealing time depends on the size and wall thickness of the product.
5. Polysulfone is close to Newtonian body in molten state, similar to polycarbonate, and its fluidity is sensitive to temperature. In the range of 3 10 -420 degrees, the fluidity will increase by 1 times when the temperature rises by 30 degrees. Therefore, the processing fluidity is mainly improved by increasing the temperature in the molding process.
Polytetrafluoroethylene plastic (F4)
(PTFE)
English name: Polytetrafluoro ethylene
Specific gravity: 2. 1-2.2g/cm3 molding shrinkage: 3. 1-7.7% Molding temperature: 330-380℃ Drying conditions:-
The material performance is 1, and the long-term service temperature is -200-260 degrees. It has excellent chemical resistance, corrosion resistance to all chemicals, the lowest friction coefficient in plastics and good electrical properties. Its electrical insulation is not affected by temperature, and it is known as the "king of plastics".
2, transparent or translucent, the higher the crystallinity, the worse the transparency. The raw materials are mostly powdered resin or concentrated dispersion, with extremely high molecular weight, which is a thermoplastic polymer with high crystallinity. Suitable for manufacturing corrosion-resistant parts, wear-resistant parts, sealing parts, insulating parts and medical device parts.
Plasticity 1. Crystalline substance, low hygroscopicity.
2. Poor fluidity, easy decomposition, and corrosive gas generated during decomposition. The molding temperature should be strictly controlled, the mold should be heated, and the resistance of the gating system to the material flow should be small.
3. Powder resin is usually formed by powder metallurgy and sintering. The sintering temperature is 360-380℃ and should not exceed 475℃. Emulsion resin is usually treated by cold extrusion and sintering, which can form an anti-corrosion layer on the surface of articles. If transparency and toughness of products are required, rapid cooling should be adopted. Extrusion molding can also be used, and pipes, rods and profiles can be extruded.
4. The melt viscosity of 4.PTFE is very high, and its volume viscosity decreases with the increase of shear stress, showing its non-Newtonian fluid characteristics.
5. Secondary processing, which can be hot pressing compounding, welding, bonding, strengthening, machining, etc. To make the final product.
ASA plastic
(Acrylic-Styrene-Acrylic Eye)
English name: acrylic style acrylic copolymer
Specific gravity: 1.05g/cm3 molding shrinkage: 0.4-0.7% Molding temperature: 170-230℃ Drying conditions: 80-90℃ for 2 hours.
Material characteristics ASA polymer is an amorphous material, which can be made into products with excellent weather resistance by extrusion and injection molding. The mechanical properties of ternary polymer ASA are usually similar to ABS resin, but the difference is that the performance of ASA is much less affected by outdoor climate than ABS resin. It is suitable for manufacturing shells, outdoor furniture and automobile exterior rearview mirrors in the general building field.
Plasticity 1. Amorphous materials with medium fluidity and high hygroscopicity must be fully dried. Plastic parts with glossy surface must be preheated and dried at 80-90 degrees for 3 hours.
2. It is advisable to adopt high feed temperature and high mold temperature, but it is easy to decompose when the feed temperature is too high (decomposition temperature > 250 degrees). For high-precision plastic parts, the mold temperature should be 50-60 degrees, and for shiny and heat-resistant plastic parts, the mold temperature should be 60-80 degrees.
3. The brands of ASA base resin sold in the market are: Luran S brand (BASF Plastic Materials Company); Gelog brand (General Plastics Company); Centrex (Monsanto)
Phenyl sulfide
(polyphenylene sulfide)
English name: phenyl sulfide
Specific gravity: 1.36g/cm3 molding shrinkage: 0.7% Molding temperature: 300-330℃ Drying conditions:-
The material has excellent performance of 1, electrical insulation (especially high-frequency insulation), hard and brittle white color, metallic sound when landing, light transmittance second only to plexiglass, coloring water resistance and good chemical stability. It has excellent flame retardancy and is a non-combustible plastic.
2, general strength, good rigidity, but fragile, prone to stress embrittlement, not resistant to benzene, gasoline and other organic solvents. Long-term use temperature can reach 260 degrees, 400 degrees in air or nitrogen to maintain stability. By adding glass fiber or other reinforcing materials, the impact strength can be greatly improved, and the heat resistance and other mechanical properties can also be improved. The density is increased to 1.6- 1.9, and the molding shrinkage is as low as 0. 15-0.25%, which is suitable for making heat-resistant parts, insulating parts and chemical and optical instruments.
The formability is 1. Amorphous materials have little hygroscopicity, but are suitable for drying and molding.
2. The fluidity is between ABS and PC, which has the advantages of fast curing, small shrinkage and easy decomposition, so the injection pressure and injection speed are high. The mold temperature is 100- 150 degrees. The taper of the main channel should be large and the channel should be short. ]
ETFE plastic
(PTFE-ethylene * * * polymer)
English name: Polytetrafluoro ethylene
Specific gravity: 1.7g/cm3 molding shrinkage: 3. 1-7.7% Molding temperature: 300-330℃ Drying conditions:-
The material performance is 1, and the long-term service temperature is -80-220 degrees. It has excellent chemical resistance, corrosion resistance to all chemicals, the lowest friction coefficient in plastics and good electrical properties. Its electrical insulation is not affected by temperature, and it is known as the "king of plastics".
2. Its chemical resistance is similar to PTFE, but better than vinylidene fluoride.
3. Its creep resistance and compressive strength are better than PTFE, and its tensile strength is high, and its elongation can reach 100-300%. Good dielectric properties and excellent radiation resistance. 1, suitable for making corrosion-resistant parts, wear-resistant parts, sealing parts, insulating parts and medical device parts.
2, wire and cable insulation, anti-corrosion equipment, sealing materials, pump valve casing and chemical containers.
Plasticity 1. Crystalline substance, low hygroscopicity. It can be processed into products by conventional processing methods of thermoplastics.
2. Poor fluidity, easy decomposition, and corrosive gas generated during decomposition. The molding temperature should be strictly controlled not to exceed 350 degrees, the mold should be heated to 100- 150 degrees, and the resistance of the gating system to the material flow should be small. Thin-walled simple products with a thickness of 0.7-0.8mm can be formed.
3. Transparent granular materials, injection molding and extrusion molding. The molding temperature is 300-330 degrees, and it is easy to change color or blister above 350 degrees. Suitable for high-speed and low-pressure molding, demoulding will be more difficult.
polytetrafluoroethylene
(Soluble PTFE)
English name: Polytetrafluoro ethylene
Specific gravity: 2. 13-2. 167g/cm3 molding shrinkage: 3. 1-7.7% Molding temperature: 350-400℃ Drying conditions:-
The material performance is 1, and it is a * * polymer of a small amount of perfluoropropyl perfluorovinyl ether and polytetrafluoroethylene. Compared with PTFE, the melt adhesion is enhanced, the solution viscosity is reduced, and the properties are unchanged. This resin can be directly processed into products by ordinary thermoplastic molding methods.
2. Long-term use temperature is -80-260 degrees, with excellent chemical resistance, corrosion resistance of all chemicals, the lowest friction coefficient among plastics, and good electrical performance, and its electrical insulation is not affected by temperature, so it is known as the "king of plastics".
2. Its chemical resistance is similar to PTFE, but better than vinylidene fluoride.
3. Its creep resistance and compressive strength are better than PTFE, and its tensile strength is high, and its elongation can reach 100-300%. Good dielectric properties and excellent radiation resistance. The flame retardancy reaches V0 level. 1, suitable for making corrosion-resistant parts, wear-resistant parts, sealing parts, insulating parts and medical device parts.
2. Insulation layer of high-temperature wire and cable, anti-corrosion equipment, sealing material, pump valve bushing, chemical container.
Plasticity 1. Crystalline substance, low hygroscopicity. It can be processed into products by conventional processing methods of thermoplastics.
2. Poor fluidity, easy decomposition, and corrosive gas generated during decomposition. The molding temperature should be strictly controlled not to exceed 475 degrees, the mold should be heated to 150-200 degrees, and the resistance of the gating system to the material flow should be small.
3. Translucent granular materials, injection molding and extrusion molding. The molding temperature is 350-400 degrees, and it is easy to change color or blister above 475 degrees. And pay attention to demoulding will be more difficult.
4. Because the melt has corrosive effect on metal, long-term production needs chromium plating.
PAR plastic (u plastic)
(polyaryl compound)
English name:
Specific gravity: 1.2- 1.26g/cm3 molding shrinkage: 0.8% Molding temperature: 300-350℃ Drying conditions: 100 ~ 120℃-5 hours.
The material performance is 1, which is a transparent amorphous thermoplastic engineering plastic with excellent heat resistance, flame retardancy and non-toxicity. It can be directly processed into products by ordinary thermoplastic molding methods.
2. It has excellent thermal performance. Under the load of 1.86MPA, its thermal deformation temperature is as high as 175 degrees, and its decomposition temperature is 443 degrees. Its mechanical properties are less affected by temperature. 1, suitable for making electrical parts with high heat resistance, flame retardancy and dimensional stability. Connector, spool, relay housing.
2. Lighting parts. Can be made into transparent lampshades, lighting lamps, car mirrors, etc.
The formability is 1. With the increase of wall thickness, the molding shrinkage increases.
2. The hygroscopicity is small, about 0. 1-0.3%, but a little moisture will cause the decomposition of polyarylate during injection molding. Therefore, the material must be dried before molding. Make its water content less than 0.02%.
phenolic plastic
English name: phenol formaldehyde (PF)
Specific gravity: 1.5-2.0g/cm3 molding shrinkage: 0.5- 1.0% Molding temperature: 150- 170℃.
Material properties Phenolic plastic is a kind of hard and brittle thermosetting plastic, commonly known as phenolic molding compound. High mechanical strength, good toughness and wear resistance, stable size, corrosion resistance and good electrical insulation. It is suitable for making insulating mechanism parts of electrical appliances and meters, and can be used under hot and humid conditions.
Plasticity 1. Moldability is good, but its shrinkage and directionality are generally greater than that of aminoplast, and it contains water volatiles. Preheat before molding and exhaust during molding. If there is no preheating, the mold temperature and molding pressure should be increased.
2. Mold temperature has a great influence on fluidity. Generally, if it exceeds 160 degrees, the liquidity will drop rapidly.
3. The curing speed is generally slower than that of aminoplastics, and the heat released during curing is large. The internal temperature of large thick-walled plastic parts is easy to be too high, and uneven hardening and overheating are easy to occur.
aminoplast
English name: MF, UF
Specific gravity: 1.5g/cm3 molding shrinkage: 0.6- 1.0% Molding temperature: 160- 180℃.
The material has good arc resistance, electrical insulation, water resistance and heat resistance, and is suitable for molding to make arc-resistant electrical devices and explosion-proof electrical insulation parts.
The formability is 1. The fluidity is good and the hardening speed is fast, so the preheating and molding temperature should be appropriate, and the coating, clamping and pressing speed should be fast.
2. The molding shrinkage is large.
3. There are many water-containing volatiles, which are easy to absorb moisture and agglomerate. When molding, it should be preheated and dried to prevent reabsorption, but if it is too dry, the fluidity will decrease. There are moisture, decomposition products and acidity in the molding process. The mold should be chrome-plated and corrosion-resistant, and it should be vented during molding.
4. The molding temperature has a great influence on the quality of plastic parts. When the temperature is too high, bubbles are easy to decompose, change color and have uneven color. The temperature is too low, the fluidity is poor, and there is no luster.
5. The material is fine, with large specific volume, and there is a lot of air in the material. When large plastic parts are molded with pre-pressed ingots, ripples and streamline are easy to occur, which is generally not suitable.
epoxy
English name: Epoxide Resin
Specific gravity: 1.9g/cm3 molding shrinkage: 0.5% Molding temperature: 140- 170℃.
The material has good mechanical properties, electrical insulation and chemical stability, and has strong adhesion to many materials, but its properties are affected by the variety and content of fillers. The alicyclic epoxy plastic has high heat resistance. Suitable for casting and low-pressure extrusion molding, potting and fixing electrical and electronic components and coils, and can also be used for repair.
Plasticity 1. Castable. Good fluidity and small hardening shrinkage, but poor thermal rigidity and difficult demoulding.
2. The hardening speed is fast, so it is generally unnecessary to exhaust when hardening, and it should be pressurized immediately after loading.
Silicone plastic (IS)
English name: Silicone
Specific gravity: 1.75- 1.95g/cm3 molding shrinkage: 0.5% Molding temperature: 160- 180℃.
The material has high and low temperature resistance, good water resistance, good high-frequency insulation, good radiation resistance and ozone resistance, and is suitable for potting and fixing electronic and electrical components and coils.
Moldability 1. Molding requires good fluidity, slow hardening speed and high molding temperature.
2. After molding, it must be cured at high temperature.