The characteristics and processing techniques of the 20
injection molding materials are as follows:
PVC (polyvinyl chloride) Typical applications: water supply pipes, household pipes, house wall panels, commercial machine casings, electronic product packaging, medical equipment, food packaging, etc.
Injection Molding Process Conditions: Drying: Drying is usually not required. Melting temperature: 185~205C. Mold temperature: 20~50C Injection pressure: can be as large as 1500bar holding pressure: can be as large as 1000bar injection speed: in order to avoid material degradation, generally use a considerable injection speed. Runners and gates: All regular gates can be used. If you are working with smaller parts, it is best to use tip-type gates or submerged gates; for thicker parts, it is best to use fan-shaped gates.
Chemical and physical properties: Rigid PVC is one of the most widely used plastic materials. PVC material is a non-crystalline material. PVC materials are often added with stabilizers, lubricants, auxiliary processing agents, colorants, impact agents and other additives in actual use. PVC materials are non-flammable, high strength, weather resistant and excellent geometric stability. PVC is highly resistant to oxidizing agents, reducing agents and strong acids. The flow characteristics of PVC are rather poor and the process range is narrow. In particular, large molecular weight PVC materials are more difficult to process (this material usually incorporates a lubricant to improve flow characteristics), so small molecular weight PVC materials are commonly used. The shrinkage rate of PVC is quite low, generally 0.2 to 0.6%.
PC/ABS Polycarbonate and Acrylonitrile Butadiene Styrene Copolymers and Mixtures: Typical Applications: Computer and Commercial Machine Housings, Electrical Equipment, Lawn Gardening Machines, Auto Parts Dashboards, Interior Finishes, and Wheel Covers.
Injection Molding Process Conditions: Drying: Drying before processing is a must. The humidity should be less than 0.04%. The recommended drying conditions are 90~110C for 2~4 hours. Melting temperature: 230~300C. Mold temperature: 50~100C. Injection pressure: depending on the plastic part. Injection speed: as high as possible.
Chemical and physical properties: PC/ABS has the combined properties of both PC and ABS. For example, the easy processing characteristics of ABS and the excellent mechanical properties and thermal stability of PC. The ratio of the two will affect the thermal stability of the PC/ABS material. The mixed material of PC/ABS also shows excellent flow characteristics. The shrinkage rate is around 0.5%.
PC Polycarbonate Typical applications: electrical and commercial equipment (computer components, connectors, etc.), appliances (food processors, refrigerator drawers, etc.), transportation industry (vehicle front and rear lights, dashboards, etc.).
Injection Molding Process Conditions: Drying: PC materials are hygroscopic, and drying before processing is important. Dry conditions are recommended from 100C to 200C for 3 to 4 hours. The humidity before processing must be less than 0.02%. Melting temperature: 260~340C. Mold temperature: 70~120C. Injection pressure: Use high injection pressure as much as possible. Injection speed: low speed injection for smaller gates and high speed injection for other types of gates.
Chemical and physical properties: PC is an amorphous engineering material with exceptional impact strength, thermal stability, gloss, bacterial inhibition, flame retardant properties and stain resistance. The PC's notch Imagine impact strength is very high, and the shrinkage rate is very low, generally 0.1% to 0.2%. PC has good mechanical properties, but its flow characteristics are poor, so the injection molding process of this material is difficult.
PET Polyethylene terephthalate Typical applications: automotive industry, electrical components (motor housings, electrical couplings, relays, switches, microwave oven internal devices).
Injection Molding Process Conditions: Drying: Drying before processing is necessary because PET is more hygroscopic. It is recommended to dry at 120~165C for 4 hours. The required humidity should be less than 0.02%. Melting temperature: for unfilled type: 265~280C; for glass filling type: 275~290C. Mold temperature: 80~120C. Injection pressure: 300~1300bar. Injection speed: Higher injection speeds can be used without causing embrittlement. Runners and gates: All conventional types of gates can be used. The gate size should be 50~100% of the thickness of the plastic part.
Chemical and physical properties: The glass transition temperature of PET is around 165C, and the crystallization temperature range of the material is 120~220C. PET has a strong hygroscopicity at high temperatures. For glass fiber reinforced PET materials, bending deformation is also very likely to occur at high temperatures. The degree of crystallization of the material can be increased by adding a crystal strengthening agent. Transparent articles processed with PET have gloss and heat distortion temperatures. Special additives such as mica can be added to the PET to minimize bending deformation. If a lower mold temperature is used, a transparent article can also be obtained using a non-filled PET material.
PP polypropylene typical application range: automotive industry (mainly using PP with metal additives: fenders, ventilation pipes, fans, etc.), instruments (dishwasher door gasket, dryer ventilation pipe, washing machine frame and cover, refrigerator Door liners, etc.), consumer goods (turf and garden equipment such as lawn mowers and sprinklers, etc.).
Injection Molding Process Conditions: Drying: No drying is required if stored properly. Melting temperature: 220~275C, please be careful not to exceed 275C. Mold temperature: 40~80C, 50C is recommended. The degree of crystallization is mainly determined by the mold temperature. Injection pressure: up to 1800 bar. Injection speed: Generally, high-speed injection molding can be used to minimize internal pressure. If defects appear on the surface of the product, low speed injection at higher temperatures should be used.
Chemical and physical properties: PP is a semi-crystalline material. It is harder and has a higher melting point than PE. Since the PP temperature of the homopolymer type is very brittle when it is higher than 0 C, many commercial PP materials are random copolymers of 1 to 4% of ethylene or a clamp copolymer of a higher ratio of ethylene. The copolymer type PP material has a low heat distortion temperature (100C), low transparency, low gloss, low rigidity, but has stronger impact strength. The strength of PP increases as the ethylene content increases.
PA6 Polyamide 6 or Nylon 6 Typical applications: Widely used in structural components due to good mechanical strength and stiffness. It has good wear resistance and is also used to make bearings.
Injection Molding Process Conditions: Drying: Since PA6 absorbs moisture easily, special attention should be paid to drying before processing. If the material is supplied in a waterproof material, the container should be kept closed. If the humidity is greater than 0.2%, it is recommended to dry in hot air above 80C for 16 hours. If the material has been exposed to air for more than 8 hours, it is recommended to perform vacuum drying at 105 C for more than 8 hours. Melting temperature: 230~280C, 250~280C for enhanced varieties. Mold temperature: 80~90C. The mold temperature significantly affects the crystallinity, which in turn affects the mechanical properties of the part. Crystallinity is important for structural components, so it is recommended that the mold temperature be 80~90C. For thin-walled, longer-flowing parts, it is also recommended to apply higher mold temperatures. Increasing the mold temperature increases the strength and stiffness of the part, but reduces the toughness. If the wall thickness is greater than 3mm, it is recommended to use a low temperature mold of 20~40C. For glass reinforcement the mold temperature should be greater than 80C. Injection pressure: generally between 750 and 1250 bar (depending on material and product design). Injection speed: high speed (slightly lower for reinforced materials).
Runners and gates: Because the solidification time of PA6 is very short, the location of the gate is very important. The gate aperture should not be less than 0.5*t (where t is the thickness of the plastic part). If a hot runner is used, the gate size should be smaller than with a conventional runner because the hot runner can help prevent premature solidification of the material. If a submerged gate is used, the minimum diameter of the gate should be 0.75 mm.
Chemical and physical properties: The chemical and physical properties of PA6 are similar to those of PA66. However, it has a low melting point and a wide process temperature range. It has better impact resistance and solubility resistance than PA66, but it is also more hygroscopic. Because many of the quality characteristics of plastic parts are affected by hygroscopicity, this should be taken into account when designing products using PA6. In order to improve the mechanical properties of PA6, various modifiers are often added. Glass is the most common additive, and sometimes synthetic rubbers such as EPDM and SBR are added to improve impact resistance. For products without additives, PA6 shrinks between 1% and 1.5%. Adding a fiberglass additive can reduce the shrinkage to 0.3% to 0.5% (but slightly higher in the direction perpendicular to the flow). The shrinkage of the molded assembly is mainly affected by the crystallinity and hygroscopicity of the material. The actual shrinkage is also a function of the plastic part design, wall thickness and other process parameters.
PA66 Polyamide 66 or Nylon 66 Typical Applications: Compared to PA6, PA66 is more widely used in the automotive industry, instrument housings, and other products that require impact resistance and high strength.
Injection Molding Process Conditions: Drying: If the material is sealed before processing, there is no need to dry. However, if the storage container is opened, it is recommended to dry it in hot air at 85C. If the humidity is greater than 0.2%, it is also necessary to carry out vacuum drying at 105 C for 12 hours. Melting temperature: 260~290C. The product for glass additives is 275~280C. The melting temperature should be avoided above 300C. Mold temperature: 80C is recommended. The mold temperature will affect the crystallinity, which will affect the physical properties of the product. For thin-walled plastic parts, if a mold temperature lower than 40C is used, the crystallinity of the plastic part will change with time, and in order to maintain the geometric stability of the plastic part, annealing treatment is required. Injection pressure: usually between 750 and 1250 bar, depending on material and product design. Injection speed: high speed (slightly lower for reinforced materials). Runners and gates: Because of the short settling time of the PA66, the location of the gate is very important. The gate aperture should not be less than 0.5*t (where t is the thickness of the plastic part). If a hot runner is used, the gate size should be smaller than with a conventional runner because the hot runner can help prevent premature solidification of the material. If a submerged gate is used, the minimum diameter of the gate should be 0.75 mm.
Chemical and physical properties: PA66 has a higher melting point in polyamide materials. It is a semi-crystalline-crystalline material. PA66 also maintains high strength and stiffness at higher temperatures. PA66 is still hygroscopic after molding, the extent of which depends primarily on the composition of the material, the wall thickness and the environmental conditions. When designing a product, it is important to consider the effect of hygroscopicity on geometric stability. In order to improve the mechanical properties of PA66, various modifiers are often added. Glass is the most common additive, and sometimes synthetic rubbers such as EPDM and SBR are added to improve impact resistance. PA66 is less viscous and therefore has good fluidity (but not as good as PA6). This property can be used to machine very thin components. Its viscosity is sensitive to temperature changes. The shrinkage of PA66 is between 1% and 2%. The addition of glass fiber additives can reduce the shrinkage to 0.2%~1%. The shrinkage ratio is large in the flow direction and in the direction perpendicular to the flow direction. PA66 is resistant to many solvents, but is less resistant to acids and other chlorinating agents.
Typical applications for PC/PBT polycarbonate and polybutylene terephthalate: gearboxes, automotive bumpers and required chemical and corrosion resistance, thermal stability, impact resistance and geometric stability The product.
Injection molding process conditions: drying treatment: recommended 110 ~ 135C, about 4 hours of drying. Melting temperature: 235~300C. Mold temperature: 37~93C.
Chemical and physical properties: PC/PBT has the combined properties of both PC and PBT, such as the high toughness and geometric stability of PC and the chemical stability, thermal stability and lubrication properties of PBT. The shrinkage rate is around 0.5%.
PE-HD High Density Polyethylene Typical applications: refrigerator containers, storage containers, household kitchen utensils, sealing covers, etc.
Injection molding process conditions: Dry: no need to dry if stored properly. Melting temperature: 220~260C. For larger molecules, the recommended melting temperature range is between 200 and 250 °C. Mold temperature: 50~95C. Plastic parts with a wall thickness of 6 mm or less should use a higher mold temperature, and plastic parts with a wall thickness of 6 mm or more use a lower mold temperature. The plastic part cooling temperature should be uniform to reduce the difference in shrinkage. For optimum machining cycle time, the cooling tunnel diameter should be no less than 8 mm and the distance from the mold surface should be within 1.3 d (where "d" is the diameter of the cooling tunnel). Injection pressure: 700~1050bar. Injection speed: High speed injection is recommended. Runners and gates: The runner diameter is between 4 and 7.5 mm and the runner length should be as short as possible. Various types of gates can be used, and the gate length should not exceed 0.75 mm. Particularly suitable for use with hot runner molds.
Chemical and physical properties: The high crystallinity of PE-HD leads to its high density, tensile strength, high temperature distortion temperature, viscosity and chemical stability. PE-HD has stronger resistance to permeation than PE-LD. PE-HD has a low impact strength. The characteristics of PH-HD are mainly controlled by density and molecular weight distribution. The PE-HD molecular weight distribution suitable for injection molding is very narrow. For the density of 0.91~0.925g/cm3, we call it the first type PE-HD; for the density of 0.926~0.94g/cm3, it is called the second type PE-HD; for the density of 0.94~ 0.965g/cm3 It is called the third type PE-HD. The material has good flow characteristics and an MFR between 0.1 and 28. The higher the molecular weight, the worse the flow characteristics of PH-LD, but the better the impact strength. PE-LD is a semi-crystalline material with a high shrinkage after molding, between 1.5% and 4%. PE-HD is prone to environmental stress cracking. Cracking can be mitigated by using materials with very low flow characteristics to reduce internal stresses. PE-HD is easily dissolved in hydrocarbon solvents when the temperature is higher than 60C, but its solubility resistance is better than PE-LD.
PE-LD Low Density Polyethylene Typical Applications: Bowls, Cabinets, Pipe Couplers
Injection molding process conditions: Drying: generally does not require melting temperature: 180~280C Mold temperature: 20~40C In order to achieve uniform cooling and economical heat removal, it is recommended that the cooling channel diameter be at least 8mm and from the cooling channel to the mold surface. Do not exceed 1.5 times the diameter of the cooling channel. Injection pressure: up to 1500 bar. Holding pressure: up to 750bar. Injection speed: It is recommended to use a fast injection speed. Runners and gates: Various types of runners and gates PE can be used, particularly suitable for use with hot runner molds.
Chemical and physical properties: Commercially available PE-LD materials have a density of 0.91 to 0.94 g/cm3. PE-LD is permeable to gases and water vapor. The high coefficient of thermal expansion of PE-LD is not suitable for processing products for long-term use. If the density of PE-LD is between 0.91 and 0.925 g/cm3, the shrinkage is between 2% and 5%. If the density is between 0.926 and 0.94 g/cm3, the shrinkage is 1.5%~4. %between. The current actual shrinkage rate also depends on the injection molding process parameters. PE-LD is resistant to a wide range of solvents at room temperature, but aromatic hydrocarbons and chlorinated hydrocarbon solvents allow it to swell. Similar to PE-HD, PE-LD is prone to environmental stress cracking.
PEI Polyetherimide Applications: Automotive (engine accessories such as temperature sensors, fuels and air handlers), electrical and electronic equipment (printed circuit boards, chip housings, explosion-proof boxes, etc.), product packaging, aircraft interior equipment, Pharmaceutical industry.
Injection Molding Process Conditions: Drying: PEI has hygroscopic properties and can cause material degradation. The required humidity value should be less than 0.02%. Drying conditions of 150 C for 4 hours are recommended. Melting temperature: 340~400C for common type materials and 340~415C for enhanced type materials. Mold temperature: 107~175C, the recommended mold temperature is 140C. Injection pressure: 700~1500bar. Injection speed: Use the highest possible injection speed.
Chemical and physical properties: PEI has a very high temperature stability, even for non-reinforced PEI, it still has good toughness and strength. Therefore, the superior thermal stability of PEI can be used to fabricate high temperature heat resistant devices. PEI also has good flame retardancy, chemical resistance and electrical insulation properties. The glass transition temperature is very high, reaching 215C. PEI also has a very low shrinkage (typically between 0.4% and 0.7%) and good isotropic mechanical properties.
Typical application range of PBT polybutylene terephthalate: household appliances (food processing blades, vacuum cleaner components, electric fans, coffee utensils, etc.), electrical components (switches, motor casings, computer keyboard keys, etc.), automotive industry (heat radiator window, wheel cover, door and window parts, etc.).
Injection Molding Process Conditions: Drying: This material is easily hydrolyzed at high temperatures, so drying prior to processing is important. It is recommended to dry in air at 120C, 6~8 hours, or 150C for 2~4 hours. The humidity must be less than 0.03%. If drying with a hygroscopic dryer, the recommended conditions are 150C, 2.5 hours?. Melting temperature: 225~275C, recommended temperature: 250C. Mold temperature: 40 to 60 C for unreinforced materials. The cooling channels of the mold are well designed to reduce the bending of the plastic parts. The loss of heat must be fast and even. It is recommended that the mold cooling channel has a diameter of 12 mm. Injection pressure: medium (up to 1500 bar). Injection speed: The injection speed should be as fast as possible (because PBT solidifies quickly).
Chemical and physical properties:
PBT is one of the toughest engineering thermoplastics. It is a semi-crystalline material with excellent chemical stability, mechanical strength, electrical insulation properties and thermal stability. These materials are very stable under a wide range of environmental conditions. PBT has a weak hygroscopic property. The tensile strength of the non-reinforced PBT is 50 MPa, and the tensile strength of the PBT of the glass additive type is 170 MPa. Excessive glass additives will cause the material to become brittle. PBT; crystallization is very rapid, which will cause bending deformation due to uneven cooling.
PMMA Polymethyl methacrylate Typical applications: automotive industry (signal equipment, instrument panels, etc.), pharmaceutical industry), industrial applications (video discs, light diffusers), consumer goods (beverage cups, stationery, etc.).
Injection Molding Process Conditions: Drying Treatment: PMMA is hygroscopic so that drying before processing is necessary. The recommended drying conditions are 90C for 2~4 hours. Melting temperature: 240~270C. Mold temperature: 35~70C. Injection speed: medium
Chemical and physical properties: PMMA has excellent optical properties and resistance to weathering. The penetration of white light is as high as 92%. PMMA products have very low birefringence and are especially suitable for making DVDs. PMMA has room temperature creep properties. As the load increases and the time increases, stress cracking can occur. PMMA has good impact resistance. The shrinkage rate is around 0.5%.
POM POM Typical Applications: POM has a very low coefficient of friction and good geometric stability, making it ideal for gears and bearings. Because it also has high temperature resistance, it is also used in pipeline devices (valves, pump housings), lawn equipment, etc.
Injection Molding Process Conditions: Drying: If the material is stored in a dry environment, drying is usually not required. Melting temperature: homopolymer material is 190~230C; copolymer material is 190~210C. Mold temperature: 80~105C. In order to reduce the shrinkage after molding, a higher mold temperature can be used. Injection pressure: 700~1200 bar. Injection speed: medium or high injection speed. Runners and gates: Any type of gate can be used. If a tunnel gate is used, it is best to use a shorter type. Hot nozzle flow channels are recommended for homopolymer materials. For the copolymer material, either an internal hot runner or an external hot runner can be used.
Chemical and Physical Properties: POM is a tough, resilient material that retains excellent creep resistance, geometric stability and impact resistance even at low temperatures. POM has both homopolymer materials and copolymer materials. The homopolymer material has good ductility and fatigue strength, but is not easy to process. The copolymer material has good thermal stability, chemical stability and is easy to process. Whether a homopolymer material or a copolymer material, it is a crystalline material and does not easily absorb moisture. The high degree of crystallization of POM results in a relatively high shrinkage rate of up to 2% to 3.5%. There are different shrinkage rates for a variety of different reinforced materials.
PPE Polypropylene Typical application range: electrical appliances such as dishwashers, washing machines, etc., such as controller housings, fiber optic connectors, etc.
Injection molding process conditions: drying treatment: It is recommended to carry out drying treatment for 2~4 hours and 100C before processing. Melting temperature: 240~320C. Mold temperature: 60~105C. Injection pressure: 600~1500bar. Runners and gates: All types of gates can be used. Particularly suitable for use with handle gates and fan gates.
Chemical and Physical Properties: Typically, commercially available PPE or PPO materials are typically blended with other thermoplastic materials such as PS, PA, and the like. These hybrid materials are still generally referred to as PPE or PPO. Mixed PPE or PPO have much better processing characteristics than pure materials. The change in properties depends on the ratio of the mixture such as PPO to PS. The mixed material mixed with PA 66 has stronger chemical stability at high temperatures. This material has low hygroscopicity and its articles have excellent geometric stability. The material in which PS is mixed is amorphous, and the material in which PA is mixed is crystalline.
PA12 Polyamide 12 or Nylon 12 Typical applications: water gauges and other commercial equipment, cable jackets, mechanical cams, sliding mechanisms and bearings.
Injection molding process conditions: drying treatment: the humidity should be below 0.1% before processing. If the material is stored in the air, it is recommended to dry in 85C hot air for 4 to 5 hours. If the material is stored in a closed container, it can be used directly after 3 hours of temperature equilibration.
Chemical and physical properties: PA12 is a linear, semi-crystalline-crystalline thermoplastic from butadiene. Its characteristics are similar to those of PA11, but the crystal structure is different. PA12 is a good electrical insulator and, like other polyamides, does not affect insulation properties due to moisture. It has good impact resistance and chemical stability. PA12 has many improved varieties in terms of plasticizing properties and reinforcing properties. Compared to PA6 and PA66, these materials have a lower melting point and density and have a very high moisture regain. PA12 is not resistant to strong oxidizing acids. The viscosity of PA12 is mainly determined by humidity, temperature and storage time. It is very fluid. The shrinkage is between 0.5% and 2%, depending on the material variety, wall thickness and other process conditions.
PS Polystyrene Typical applications: product packaging, household goods, tableware, trays, etc., electrical (transparent containers, light source diffusers, insulating films, etc.).
Injection Molding Process Conditions: Drying: Drying is usually not required unless stored improperly. If drying is required, it is recommended to dry at 80C for 2-3 hours. Melting temperature: 180~280C. The upper limit for the flame retardant material is 250C. Mold temperature: 40~50C. Injection pressure: 200~600bar. Injection speed: A fast injection speed is recommended. Runners and gates: All conventional types of gates can be used.
Chemical and physical properties: Most commercial PSs are transparent, amorphous materials. PS has very good geometric stability, thermal stability, optical transmission characteristics, electrical insulation properties and a very small tendency to absorb moisture. It is resistant to water, diluted inorganic acids, but can be corroded by strong oxidizing acids such as concentrated sulfuric acid and can swell and deform in some organic solvents. Typical shrinkage is between 0.4 and 0.7%.
SA styrene-acrylonitrile copolymer Typical application range: electrical sockets, housings, etc., household goods kitchen appliances, refrigerators, TV sets, etc., automotive industry (headlights, dashboards, etc.), household items (tableware, Food knives, etc.), cosmetics packaging, etc.
Injection Molding Process Conditions: Drying: SA has some hygroscopic properties if not properly stored. The recommended drying conditions are 80C for 2 to 4 hours. Melting temperature: 200~270C. If a thick walled product is processed, a melting temperature below the lower limit can be used. Mold temperature: 40~80C. For reinforced materials, the mold temperature should not exceed 60C. The cooling system must be well designed because the mold temperature will directly affect the appearance, shrinkage and bending of the article. Injection pressure: 350~1300bar. Injection speed: High speed injection is recommended. Runners and gates: All regular gates can be used. The gate size must be appropriate to avoid streaks, freckles and voids.
Chemical and physical properties: SA is a hard, transparent material. The styrene component makes SA hard, transparent and easy to process; the acrylonitrile component gives SA chemical and thermal stability. SA has a strong load carrying capacity, chemical resistance, thermal deformation resistance and geometric stability. The addition of glass fiber additives to SA can increase the strength and resistance to thermal deformation and reduce the coefficient of thermal expansion. The Vicat softening temperature of SA is about 110C. The deflection temperature under load is about 100C. The shrinkage rate of SA is about 0.3 to 0.7%.
Allyl ester resin
Allyl esters are allyl based esters. Allyl esters based on monobasic or dibasic acids can be used as low tack monomers or thermoplastic prepolymers. They are often used as crosslinkers for unsaturated resins and are also used in the processing of reinforced thermosetting molding materials and high performance transparent materials.
The resin retains its original electrical properties under high temperature and high humidity conditions, and the molded article has the advantages of dimensional stability, chemical resistance, mechanical strength and heat resistance. Allyl ester resin molding compounds with flame retardant are commercially available, and some varieties have been approved by Underwriters Laboratories. Some resins, tested with their thin test pieces, have a flame-retardant UL94 V-0 flammability rating and are resistant to strong arc ignition and arc tracking.
Chemistry and properties
Commercially the most widely used allyl esters are diallyl phthalate and diallyl isophthalate monomers and prepolymers, which are easily converted into thermoset molding compounds as well as glass cloth and paper. Prepreg.
Diethylene glycol bis(allyl carbonate)
Because of its excellent transparency, it is used more and more widely. It is the main material for making plastic lenses due to its light weight, dimensional stability, abrasion resistance and easy coloring. Other applications include dashboard covers, camera filters, and all areas of the fast-growing glass industry.
Recently, a modified bisphenol A bis(allyl carbonate) has emerged, which is a transparent polymer with a high refractive index (1.56) and a diethylene glycol double (carbonic acid propylene). The refractive index of the ester is also high. In addition, there is a modified type used in lens design that changes the design of the lens. Other commercially valuable monomers are diallyl fumarate and diallyl maleate. This is a class of highly reactive trifunctional monomers containing two double bonds that can be polymerized. Allyl methacrylate also has bifunctional properties and can be used as a crosslinking agent and a monomeric intermediate. Diallyl cyanurate can be used as a crosslinking agent for unsaturated polyester resins.
