Commonly used plastic materials, applications, their advantages and disadvantages.

Business information
The ACS is exclusively produced by Showa Denko, with only a form of colored granule, which is slightly higher than standard flame retardant ABS.
Styrene resin ABS.
The triple polymer ABS has been commercialized since the 1940s, and sales have increased year by year, and now it has become the biggest seller in the world.
The U.S. alone sold more than 1.2 billion pounds of thermoplastics in 1989 alone. In commodity plastics and high performance engineering.
Between plastic and plastic, ABS occupies the position of a unique "transition" polymer.
Chemistry and property
The versatility of ABS comes from its three monomer structural units - acrylonitrile, butadiene and styrene. Each component provides a different set of useful properties for the final polymer. Acrylonitrile mainly provides chemical resistance and thermal stability; Butadiene provides initial and impact strength; The styrene group provides hardness and machinability for ABS. There are three kinds of production techniques -- emulsion, continuous body method or suspension method, and the content of styrene in ABS raw materials produced by either method is 50% or higher. Usually at least two processes are used together to optimize the final product. ABS resin belongs to two-phase system: styrene-acrylonitrile copolymer (SAN) is a continuous phase, and butadiene derived rubber is a dispersed phase of elastomer.
There is actually a small amount of styrene and acrylonitrile on butadiene rubber with copolymerization (grafting), incompatible hard SAN and rubber compatibility. Therefore, ABS is considered to be one of the first commercially successful polymer alloys.
Change the ratio of the three monomers A, B and S, the molecular weight of the polymer and the form of rubber phase can have infinite ABS products to choose from. For example, the particle size of the rubber phase can be small from 0. One micron to a few microns. The average particle size and particle size distribution in the rubber phase have an important influence on the overall balance of polymer properties, including strength, toughness and appearance. Large rubber particles increase toughness and reduce smoothness.
The properties of ABS resin have a significant influence on the performance of ABS resin. Generally, the longer the polymer chain, the higher the strength performance (including impact and ductility), and the lower the flow performance.
Finally, hard SAN rubber facies will affect the ratio of ABS resin of equilibrium between the liquidity and shock resistance, for example, the increase of rubber content will increase the impact strength and toughness of ABS materials, but often at the expense of the poor liquidity. The balance between flow performance and impact resistance is the basic product feature of ABS material, which distinguishes the ABS materials from ordinary USES.
Alloys and special supplies.
If add more to the polymerization process a variety of monomers, or mixed with chemical additives, or with another plastic blending or alloy, can further broaden the scope of performance based on ABS resin.
For example, in the process of polymerization, the addition of a methyl styrene or a maleate cake can produce ABS based materials with high thermal deformation temperature. The use of methyl methacrylate can match the refractive index of the hard and rubber phases to make the material more transparent.
Usually, ABS resin and additives in the process of polymerization ingredients as the last process, or as a separate process in extrusion or banbury mixer, such as the melt mixing equipment for molten ingredients. The typical additives can improve the performance of uv resistance and thermal stability, flame retardancy and antistatic properties. Enhanced ABS with higher strength and hardness has been commercialized.
A useful feature of ABS is the ability to form a series of alloys with a variety of different polymers that have a new range of properties beyond the traditional equilibrium performance.
The most common is ABS- a polycarbonate (PC) alloy, which exhibits improved impact resistance (especially at low temperatures) and high heat resistance compared with basic ABS terpolymer. They have strong applicability in automobile market, such as meter panel and wheel baffle. By adding additives, the PC/ABS alloy can also be made into flame retardant materials and has achieved great success in the commercial machine market. Another commercial way for flame retardant ABS materials is to make alloy with PVC. PVC is a flame retardant material.
ABS is made of a crystalline polymer alloy, which has stronger chemical stability. Has commoditized: ABSPBT (polyethylene terephthalate butene ester) nylon alloy and ABS alloy, its target market includes the lawn and garden tools, automotive interior materials, power tool shell and cosmetics packaging materials.
A new series of ABS alloys that do not require chemical additives or fillers (carbon or metal) and show "permanent" electrostatic dissipation. This kind of permanent antistatic property is resistant to wiping and is relatively sensitive to temperature.
These alloys are not weathering and have good shading ability, and the target is mainly in the field of material processing. For more information about ABS alloys, see "alloy and blending" on page 5 of this book.
processing
ABS is an amorphous thermoplastic that softens rather than suddenly melts at a certain temperature range. ABS is slightly hygroscopic and should be dried before melting. ABS is usually sold with pellets, and the colors are primary colors, precolored or mixed colors, and are sold as natural powders. It can also be used to satisfy the final user's precise requirements. All kinds of ABS materials are easy to accept the common secondary processing, such as machine processing, adhesion, fastening, electroplating, painting and so on.
One of the basic strengths of ABS resin is the processing performance. ABS material has a wide range of processing conditions and good shear flow characteristics. Many forms of processing are available, including injection molding, extrusion, thermal forming, structural foam and blow molding.
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ABS products have a wide range of performance, wide range of processing, and a more balanced price and performance, which makes its application market widely transported. This is ABS's largest market in the United States, and it needs about 300 million pounds of resin a year. There are many applications for cars, including cars and cars. For internal injection moulding, high heat resistance, general purpose and low smooth materials have been developed for instrumentation panel, control panel and other automobile interior parts.
ABS is widely believed to be the preferred plastic for making components inside cars. The external application includes the various ribbons made of the heat sink grille, the front lampshade and the large truck. Electroplated ABS can be used for handle, lamp frame, mirror seat, grille and decorative belt. Apparatus. In 1989 the American appliance market consumed 2. 500 million pounds of ABS resin, most of which is consumed in the main equipment, extruded a hot molding door and oil tank lining. Transparent ABS is used as freezer compartment for refrigerator.
Other USES for the appliance market include kitchen appliances, power tools, vacuum cleaners, sewing machines, and injection moulds for electric hair dryers. ABS is favored because of its strength, toughness and smoothness. A good balance between coloring power, processing performance and price.
Commercial machines. It is a large "value-added" market for ABS, which in 1989 was about 75 million pounds of resin, which has historically maintained a strong growth rate. Flame retardant grade material is suitable for computer shell and control board. Building. ABS is widely used in this field, especially in drainage, wastewater and exhaust (called DWV) pipes, and injection pipe fittings. In 1989, the United States sold more than 1. 500 million pounds. ABS material can coexist with low price PVC in the market of DWV pipe, because it can provide improved low temperature impact performance, easy bonding and much lower proportion.
ABS is used in many parts of the consumer and industrial markets. This includes toys, medical devices, lawns and garden appliances, furniture, cosmetic packaging, shipping, drainage, bags and showers. It's very beautiful. Good processing performance, high smoothness and favorable balance between cost/performance determine the suitability of ABS for this broad market segment.
Business information
In terms of industrial standards, ABS has a long history, and most markets and applications of such products and services are not yet mature. Demand for ABS is expected to grow by 3 to 5 per cent a year over the next few years. ABS's growth rate in Europe is estimated to be similar to that of the United States, while the Pacific region is about 7 to 10 percent a year. ABS based alloys are even expected to grow faster than standard ABS resins. On the price list of 1991, the price range of the ordinary ABS injection grade products is: the price of the impact/original resin of the mid-range is 1. $47 per pound; The price of the impact strength grade material is 1. 62 dollars per pound. Generally, the price of extruded products is 5% ~ 10%. Special flame retardant grade and high heat resistance starting price are returned. Sixty-five dollars. This is the wholesale price of the original material.
Here are three major ABS producers in the United States: general plastics (Cycolac), Lustran, dow chemical (Magnum). General plastic co., LTD. (USA) has the largest domestic production capacity and occupies the first place in the market share. All three suppliers have production capabilities outside the United States.
Polypropylene random copolymer.
Polypropylene random copolymer is also a kind of polypropylene, the basic structure of its polymer chain is modified by adding different kinds of monomers. Ethylene is the most commonly used monomer, which causes changes in the physical properties of polypropylene. Compared with PP homopolymer, random copolymer improved optical properties (increased transparency and reduce turbidity fog), improve the shock resistance, increased flexibility, lower melting temperature, thus reducing the hot melt after temperature; At the same time, the chemical stability, water vapor isolation performance and organ sensory properties (low odor and taste) are basically the same as homopolymer.
Developed combined improved transparency and impact strength of PP random copolymer, used in blow molding, injection molding, film and sheet extrusion processing field, food packaging materials, medical packaging materials and consumer goods.
chemical
PP random copolymer generally contains 1-7% (weight) of ethylene molecules and 99-93% (weight) of propylene molecules. In polymer chains, the ethylene molecules are randomly inserted between the molecules of propylene. In this kind of random or statistical copolymers, most (75%) usually ethylene is inserted into the way of combination, called the X3 group (three consecutive ethylene (CH2) arranged in the main chain), it can also be considered a vinyl molecules between two propylene molecules.
Several molecules insert another 25% of ethylene is combined into the main chain, also called X5, because there are five consecutive methylene group (two ethylene molecule inserted between two propylene molecules together). It is difficult to distinguish X5 from higher groups such as X7 and X9. In view of this, the ethylene content of XS and higher groups is counted as > X3 %.
The random ratio of X3 / X5 can be determined. When the percentage of the group above X3 is large, the crystallinity of copolymer will be significantly reduced, which has a great influence on the ultimate performance of the random copolymer. The high content of ethylene in copolymer has an effect on the crystallinity of the polymer, which is similar to the effect of high random polypropylene content.
The random PP copolymer is different from the homopolymer, because the ethylene molecules that are inserted into the polymer chain without the regulation block the crystallization arrangement of the polymer molecules. The reduction of copolymer crystallinity causes the change of physical properties: the random copolymer and PP homopolymer have less rigidity, better impact resistance and better transparency. Ethylene copolymer also has a lower melting temperature, which is the advantage of their application in some aspects.
Random copolymers contain a large number of removable and random PP, as well as polymer chains with a much higher content of ethylene. The higher can take content of leather, depending on the different polymerization process, different degree of copolymer materials consist in all of the goods, and to meet the federal food administration (FDA) causes difficulties about the regulation of food contact.
Manufacturing methods
The ethylene/propylene random copolymer is made by polymerization of ethylene molecules and propylene molecules simultaneously, and the reactor is the same as that of PP. The ethylene molecule is smaller than the propylene molecule, and the reaction is faster than that of propylene. This reduces the stereospecificity of the catalyst and increases the activity, which leads to the increase of random polypropylene products. In order to reduce the random material generated, it is necessary to reduce the reaction temperature, thereby reducing the activity of the catalyst, and reduce the random isomer content in the final product, a product has a balanced performance.
Ethylene content in random copolymer of high (> 3%) in the process of production to handle more difficult, it is also hard to polymerization in hexane diluent, because the reaction of secondary by-products (random copolymer of polypropylene and ethylene content high) can be dissolved in hexane. The same is true for the bulk polymerization of liquid propylene, although the solubility is low. Hexane dilution process produces a large number of by-products, must be in hexane recirculation phase separation, which increases the total production cost, but can get cleaner or a small amount of soluble components of the polymer. In bulk polymerization, these impurities remain in the polymer and cause trouble in processing thin sheets of material. Furthermore, there are more soluble impurities in the products. The use of organic solvent for secondary cleaning can remove most impurities, but increase the total production cost of copolymer. In general, when the content of the byproduct is high, the thin sheet random copolymer will become more viscous, when the ethylene content is higher than 3. This problem is more prominent when it comes to 5% (weight).
Increased processing and low reactor temperatures lead to low production rates of random copolymers. And the production cycle of random copolymer is usually very short. These factors make the total production cost of the random copolymer higher than the homopolymer, especially the random copolymer with high ethylene content.
The melting point of copolymer is directly related to the content of ethylene. According to reports, ethylene content was 7%, the low melting point of copolymer of 152 ° F. The effect of X3 content on the melting point of copolymer is more significant than that of children and higher gene content. It also depends on the catalyst itself, and the ability to use the X3 group to replace the X5 group with ethylene.
performance
Physical properties: generally speaking, random PP copolymer is more flexible and less rigid than PP. When they are on the temperature dropped to 32 ° F, can also maintain moderate impact strength, and when the temperature dropped to - 4 ° F, the usefulness is limited. The bending modulus of copolymer (the secant modulus of 1% strain) is within the range of 483 ~ 1034MPa, while the homopolymer is within the range of 1034 ~ 1379MPa. The molecular weight of PP copolymer material has less influence on rigidity than that of PP. The impact strength of cantilever beam with incisions is generally 0. 8 to 1. 4 feet per inch. Chemical resistance: random PP copolymer on acid. Alkali, alcohol, low boiling point hydrocarbon solvents and many organic chemicals have strong resistance. At room temperature, PP copolymer is basically insoluble in most organic solvents. Also, when exposed to soap and soap lye. Unlike many other polymers, water - based reagents and alcohols do not cause environmental stress fracture damage. When in contact with certain chemicals, especially liquid hydrocarbons. Chlorinated organic compounds and strong oxidizing agents can cause surface cracks or swelling. Nonpolar compounds are generally more easily absorbed by polypropylene than polar compounds.
Barrier properties: PP copolymer and homopolymer have very low water vapor permeability (0. 5 g/ml / 100 square inches / 24 hours). These properties can be improved by orientation. The tensile blow molding polypropylene bottle has improved the water vapor permeability to 0. 3. Oxygen permeability to 2500.
Electrical properties: generally, polypropylene has good electrical properties, including high dielectric strength, low dielectric constant and low loss factor; However, electric power applications generally choose homopolymers.
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The random copolymers are mainly used for high transparency of film, blow molding and injection molding. The copolymer with high ethylene content is widely used as the special seal layer of the co-extrusion thin film structure due to the low initial temperature of the welding.
Impact - resistant PP copolymer.
PP has a lot of useful properties, but it lacks inherent toughness, especially under the condition that it is below its glass temperature. However, by adding impact modifier, its impact resistance can be improved. Traditionally, it is an elastomer, usually ethylene-propylene rubber. It is generally believed that the rubber particles in the semi-crystalline polypropylene matrix can form many stress concentration points on the interface, and 5. Local deformation to prevent fracture spreading.
The impact modifier has been added in the blending, and recently, the field synthesis of elastomers has been of commercial importance. In addition, a new series of impact modifiers are being promoted to replace the ethylene propylene rubber, which is Flexomer polyolefin, Exact plasticizer and Insite polymer. These are olefin polymers that fill the gap between the extremely low density polyethylene and the traditional ethylene-propyl elastomer.
Chemistry and performance
Isotactic PP homopolymer, catalyzed by the ziegler-natta catalyst system, is polymerized by propylene. The ethylene propylene rubber components are synthesized in a series of reactors, or purchased in advance, and then mixed with PP in extruder. The generated anti-impact polypropylene is sold after granulation. The anti - impact PP copolymer can precisely control its important properties by selecting suitable catalyst composition and reactor conditions. The catalyst composition and reactor conditions determine the crystallinity of the matrix resin, the composition and quantity of rubber components and the distribution of the total molecular weight.
The impact PP is one of the lightest thermoplastics, with a density of less than 1, and the price per pound is lower than PET, PBT, high impact polystyrene and ABS. According to the specific volume, the unit volume cost of the anti-impact PP is lower than that of the above-mentioned resins and PVC. Only HDPE is comparable in this respect. Shock resistant PP at moderate temperature processing, usually range is 350 ~ 350 ° F.
The anti - impact polypropylene copolymer has a wide - spectrum melt flow rate, usually ranging from 1 to about 30. The resin with the highest melt flow rate is usually made by the material "visbreaking and cracking" of materials with low melt flow rate. In other words, a one-step reaction to the material from the reactor is made to reduce the average molecular weight, thus making the product with a higher melt flow rate.
Anti-impact polypropylene copolymer has high resistance to chemical and environmental stress fracture. After treatment, the material can have excellent impact strength of cantilever beam and low impact performance of Ghana. The range of impact strength of cantilever beam is back. 5 to 15 feet/inch; Under - 40 ° F, Ghana's impact strength range of 15 to 300 inches / $# 8226 pounds.
The rubber group is divided into polypropylene to provide the impact strength, but the anti-impact polypropylene is compared to the homopolymer, reducing the stiffness and thermal deformation temperature. The anti-impact polypropylene copolymer with filler can tolerate higher temperature without deformation. The packing is usually fiberglass. Mica, talc and calcium carbonate. The end users of these polymers should be aware of the tradeoffs between the different melting strength, melt flow rate, stiffness and thermal deformation temperature of each product.
use
The main commercial use of anti - impact polypropylene is used in automobile, household articles and equipment. Its impact resistance, low density, coloring and processing properties make it ideal material. Moderate impact resin with high melt velocity has high flow performance, which is particularly useful in injection molding large parts such as car panels.
High capacity have lower melt flow rate of the resin (usually less than 2), can be converted to penetration resistance excellent film, the film impact resistance and resistance to the steam sterilization ability, suitable for one-off medical waste bags. The extruded sheet can be processed into large and thick parts by hot forming, such as the protective plate in the automobile industry and the lining of the trunk of the car.
The mechanism of the impact resistance of elastomer component modified polypropylene can induce stress whitening when the material is subjected to shock.
Most applications are based on the dispersion of the elastic component in the polypropylene matrix. On the contrary, new types of bumpers are being developed. The result is a molecular composite structure.
Business information
It is estimated that in the past five years, the demand for anti-impact polypropylene copolymer has been increasing at about 15 per cent a year. Future growth will be accelerated by increased penetration of the car market, which will become more important in automotive applications.
polypropylene
The most prominent property of polypropylene is polyhedral, which is suitable for many processing methods and applications. Its value and versatility are mainly derived from excellent chemical resistance, lowest density and highest melting point and moderate cost in bulk thermoplastic.
Chemistry and performance
The difference between polypropylene (PP) and polyethylene (PE) is that the former has a methyl group on every other carbon atom, which makes the chain harden. Unless these methyl groups are on the same side of the chain, the polymer doesn't crystallize. Before Natta and Ziegler (independently) developed stereotactic catalysts, they could only produce soft and cohesive polypropylene. The hardness and resistance of commercial plastics are derived from crystallization. The chain of PP is harder than PE, so PP has higher melting temperature and tensile strength, but less crystallinity. The melting point of PP homopolymer is about 330 ° F, depending on the heating rate and thermal history.
Insertion of ethylene (random copolymerization) on the PP chain will make the chain less regular and softer, thus reducing the crystallinity, modulus, melting point and melting point of the polymer. A typical random copolymer is relatively transparent, melting point in the range of 293-305 ° F. When the ethylene content increases, the crystallinity of the polymer becomes lower and lower, and finally becomes ethylene propylene rubber (EPR).
The other kind of important copolymer is anti - impact non - homogeneous copolymer. These products are made by polymerization of rubber (sometimes PE) in the homopolymer matrix. The rubber used is usually EPR, which generates a phase state separated from the homopolymer matrix, forming a light fog. Translucent appearance. These materials are not real block copolymers, because the rubber phase can be extracted by solvent. With EPR and PP, a similar product is used, and the anti-impact copolymer has a melting point similar to the homopolymer.
Molecular weight and molecular weight distribution are very important in PP processing. It's 446T and 4. The melt flow under 75 pounds of load is an index of melt viscosity, which is related to the weight average molecular weight. The melt flow of commodity polypropylene is low to 0. 25 g / 10 minutes to as high as 800 g / 10 minutes. The ratio of the weight average molecular weight to the average molecular weight of the molecular weight distribution shows that the ratio of high crystallinity PP can be as high as 11. The PP used for the blown fabric can be as low as 2. L,. This ratio is very important in the process of fiber spinning, and it affects the extrusion, extrusion, molding internal stress and orientation process.
Like most polymers, polypropylene oxidizes, especially during melting. As far as PP is concerned, it is necessary to remove free radicals that attack tertiary hydrogen to protect the polymer. For the long-term use of PP at high temperature, the complex multi-component stabilizer system is adopted. For situations that limit smell or taste, a stable system must be very simple. If used to protect against sunlight (uv), add black carbon or use a special stabilization method.
The tensile strength of ordinary PP is 34. 5MPa, the bending modulus is about 1723MPa. The tensile strength is 100MPa and the bending modulus is 9650MPa glass filled grade PP. The bending modulus of the mineral filler PP can be up to about 4480MPa, but the tensile strength is not much increased. In less than a 75 ° F remain ductility. Anti-impact copolymer with low tensile strength to 18 6MPa and low bending modulus to 689MPa is not the most recent variety. The modern polymerization process can produce the blank material between polypropylene and olefin rubber.
In addition to strong oxidants and non-polar solvents, PP has a strong resistance to chemical erosion. For example, concentrated sulfuric acid with nitric acid or heat can degrade PP, but a less concentrated solution is harmless to PP. Liquids such as gasoline, xylene and chlorinated hydrocarbons can cause the PP to swell and become soft. The swelling degree of copolymer is higher than that of homopolymer. After the PP is removed from this solvent, its size will be restored. Due to the high surface inertia of PP, it is difficult to print, paint and glue on PP without flame treatment or similar technology.
The combustion of polypropylene is very high and it is difficult to make flame retardant products, but there are several kinds of flame retardant grade PP sold in the market. PP is also an excellent electrical insulator with low dielectric constant and loss factor. It has good moisture resistance, but it is not a good barrier to oxygen.
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Fibre is a major market for PP. By stretching or orienting, the tensile strength can be increased by 15 times. Silk products include clothing, diapers, and non-woven fabrics. Furniture leather, agricultural bag, cord, floor fabric, belt. Carpet and carpet back village. PP can also be cast or directed to stretch into thin films. Targeted films can be used as cigarettes. Packaging materials for sweets and many items; The non-directional film is used for capacitors or packaging materials.
PP sheet is used in food containers for heating and forming, which must comply with FDA regulations. The new type of extremely low - scale products can be extended by calender and compete with soft vinyl resin for the market.
PP can be processed into hollow products by injection blow molding, extrusion blow molding or stretching blow molding. In order to improve the performance of blow molding and thermal forming, high melt strength grade PP has been developed.
In the market, there is a rapid processing extrusion adhesive grade PP; The excellent electrical properties of polypropylene make it suitable for insulation materials for telephone lines and data transmission cables.
Many different types of injection parts are made from PP or its impact copolymer. In the car market. The copolymer is used for internal loading and panel, external components and battery, etc. The homopolar and filler levels are used for engine casing or dashboard.
A piece of glass filled with PP as an ornament or utensil. All non-fillable PP resins are available for writers, medical devices, including disposable radioactive sterilizers, mainly using low cost homopolymer and random copolymers. Thin-walled molded containers extend the range of PP's traditional packaging market, such as tamper-proof seals and dispenser.
Polyphthalamide.
Polyphthalamide (PPA) resin is a semi-aromatic polyamide based on terephthalic acid or phthalic acid. Both half and amorphous, but also an amorphous state, the glass transition temperature at about 255 ° F. The non-crystalline PPA is mainly used for blocking performance; PPA resin is mainly used for injection molding and other melting process. The latter is mainly introduced in the latter - half - crystalline PPA resin, except for special mention. Half and amorphous PPAS melting point is about 590 ° F, in the form of opaque rectangular section of supply.
performance
The PPA resin is stronger than the fat polyamide, such as nylon 6,6, etc. It's less sensitive to water; Better thermal performance; And the creep, fatigue and chemical resistance are much better. For example: PPA resin containing 45% short glass fiber, about 276 mpa tensile strength, bending modulus of more than 13786 mpa, heat deformation temperature (HDT) 549 ° F. Even if the mineral filler is PPA, the tensile strength can reach 117MPa. PPA is less malleable than nylon 6,6. However, the unenhanced impact modified PPA resin has been developed, and the impact strength of the gap cantilever beam is as high as 20 feet [$#8226] / inch.
All polyphenolamine absorbed certain moisture, causing plasticization and size change. Nylon 6, 6, for example, under 23 ° F, the relative humidity is 100%, can absorb 8. 9 percent of the water, which makes the glass melt at 6. 5 ° C below 20 ℃, size 2. 3%. Under the same conditions, PPA resin can absorb about 6% of the water, but the glass transition temperature Tg will not lower than 40 ℃, with the size of the growth, not more than 1. 0%.
As previously mentioned, the use of glass reinforced PPA resin has high HDT value, can endure high temperature, short-term effect, for example: in a furnace or in vapor phase and in the process of infrared countercurrent unity. PPA resin thermal oxidation stability make it capable of long-term high temperature, glass reinforced PPA, within 000 hours, its continuous use temperature up to 330 ° F.
Under normal environmental conditions, PPA resin usually exhibits excellent solubility in fatty hydrocarbon, aromatic hydrocarbon, chlorinated hydrocarbon, ester, ketone, alcohol and most aqueous solutions. This type of resin cannot withstand strong acid and strong oxidizing agents. Soluble in phenol and cresol. PPA is not a natural flame retardant. According to the UL94 standard, the resin of the flame retardant grade is VO, until 0. 031 inches thick.
processing
Although other melting processes can be used, most PPA resins are processed by traditional injection molding. Pre-dry the PPA material to less than 0. The 1% humidity level is then loaded into a heat-sealed metal village bag or box that guarantees that the PPA material will not be dry before processing. The acceptable humidity level of the processing technology is 0. 15% or less. The wet resin can reduce the molecular weight and cause the corresponding mechanical loss. Use desiccant storage hopper dryer, under the condition of 175 ° F is easy to dry the resin to the dew point even lower humidity over a 25 ° F. Dry time depends on the amount of water absorbed, usually within 4-16 hours.
Injection when the melting temperature within the scope of the 615-650 ° F, the material stay in the barrel for a time not more than 10 minutes, so injection molding products and mechanical properties of the best. Require at least 275 ° F, mold temperature in order to fully crystalline and dimension stability is the best product. Parts with thick walls can be molded at lower mold temperatures due to slow cooling. Mold temperature is essential for the optimum surface exteriorization of finished parts. Used for vacuum metallized into electroplating metal mineral filler grade of PPA resin mold surface temperature for 350 ° F.
use
Due to the outstanding physical, thermal and electrical properties of the PPA resin, especially the moderate cost, it has a wide range of applications. These properties, together with excellent chemical resistance, make PPA a candidate for many USES in the automotive industry. A better aerodynamic body design with a higher performance motor will increase the temperature of the engine case, making the traditional thermoplastic plastic appear inapplicable. These new requirements make PPA one of the candidate materials for making the following components: automotive headlight reflectors, bearing seats, pulley, sensor housing, fuel line elements and electrical components.
The development direction of electrical components is miniaturization and high temperature solidarity, such as infrared consolidation and vapor solidarity, which requires the superior performance of PPA. The flame retardant PPA has excellent electrical performance, high HDT value, high temperature bending modulus, and thin wall component with minimal overburden processing. Therefore, it is suitable for making switchgear. Connector, brush holder and motor bracket.
The mineral filler grade PPA is used for reflective surfaces and metal-plated aspects, including automotive headlights, decorative pipe fittings and hardware. Unenhanced impact modifier PPA has excellent balance mechanical properties and high temperature performance. The exceptional toughness and the effect of these properties on humidity are minimal, and its USES include oil field components, military supplies, sporting goods, fan impeller and gear and personal safety supplies.
Business information
The company that produces the non-crystal PPA resin is: Amoco features products company (Amodel), dupont (Eytel), Dynamit Nobel (Trogamid). Amoco and mitsui petrochemical co., LTD., respectively produce the crystalline PPA resin for Amodel and Arlen.
Modified polyphenylene oxide
Polystyrene can be mixed and polyphenyl ether in any proportion, and relatively easy to give products with flame retardant, make may produce broad-spectrum physical properties, heat resistance and flame retardant properties of materials. The thermal deformation temperature of existing products in the range between 170 ~ 460 ° F. Processing methods from standard molding and extrusion to blow molding and structural foam molding. Both the general and the flame retardant grades are extremely versatile. For standard molded products, the minimum thickness ranges from 0. 060 to 0. 125 inches for structural foam, minimum thickness range from 0. 125 to 0. 250 inches, its flammability range is from UL94 HB to v-o.
Because of the hydrophobic properties of these two main polymer components, most modified polyphenyl ether alloys have low moisture absorption capacity. Therefore, in the wide humidity and temperature range, there is good electrical performance. The degree of chemical erosion of water, most salt solutions, acids and bases is extremely low. However, exposure to some organic chemicals causes polymer alloys to soften or crack.
Chemistry and property
Modified polyphenylene oxide (PPO) from 2, 6 - dimethyl phenol oxidative coupling polymerization, it is a kind of linear and amorphous polymers, the Tg of about 410 ° F. PPO can form an alloy with styrene (PS) in a wide range. PS, which is usually high anti-impact (HIPS), provides excellent melt flow characteristics. However, because of the PS Tg is about 220 ° F, it join reduces the thermal deformation of polymer blend. PPO polymers, with very high Tg, increase the thermal deformation of blends. However, the addition of PPO polymers leads to the increase of melt viscosity, which makes it difficult to process the forming process.
Because the flame retardant properties of PPO are much better than styrene resins, the blends introduced by PPO can easily be flame-retardant by adding the heat-resistant phospho-based additives.
Polymer blend can be further used rubber improved toughness, impact modifiers used glass and graphite fiber to improve the rigidity, and in all kinds of packing to improve strength, stiffness and flame retardancy, and at the same time reduce the mold shrinkage. The use of impact strength modifier can make the resin of many brands highly malleable in a certain temperature range. A good formula system will typically impact the cantilevered beam of the product up to 7 feet [$#8226] / inch, and the Gail impact will hit 30 feet [$#8226]. At temperature as low as a 40 ° F, material still maintain good ductility. The stiffness of the fiber is determined by the type and number of fibers used. Graphite fiber is the hardest, with 10% packing, the bending modulus exceeds 4136MPa. Glass is the most commonly used because of its low price. When glass is 30% (wt), the product modulus exceeds 6893MPa. Mineral filler increases the tensile strength of the PPO alloy to over 6893MPa and increases the modulus moderately. In addition, fiber and packing reduce mold shrinkage.
Special brand
Unique material consists of a series of glass filling goods, used to improve the rigidity and dimensional stability of foaming brand, can be foamed brand for microwave food packaging, used in the telecommunications and device can spray town and electroplating grade, used for computer and electrical equipment within the structure of high modulus brand, as well as blow molding grades for the house and furniture.
A series of products based on PPO and nylon blend have been developed. PPO provides excellent heat resistance and toughness, crystalline nylon phase oil/gasoline/solvent. The moisture absorption and moisture increase of PPO and nylon alloy are much lower than that of nylon. The PPO/nylon alloy has lower density, higher toughness, and less tool/mechanical wear than the mineral-filled nylon. PPO/nylon brand is used as the required paint temperature of 370 ° F car plate. These brands have replaced nylon in automotive applications, used in components that require high heat and ductility, as well as hardness or dimensional stability, such as wheel cover, mirror frame, joint and coupling. The PPO/nylon brand is used in liquid treatment applications that require chemical resistance, size stability and heat resistance. The large part is made from the resin of the blow molding plate or from the hot forming sheet.
processing
Most PPO based on polymer blends have excellent processing stability, so a wide range of products can be processed on most professional equipment. The screw injection molding machine is more popular than plunger type equipment because it can provide more rapid and uniform heat. Usually, the processing temperature is between 500 to 600 ° F.
Extruder resin can be machined on single or double screw equipment. The plate number based on polyphenyl ether can be machined on the equipment with exhaust or no exhaust. The extruded sheet is easy to vacuum and has good rolling uniformity. Blow molding brand has enough thermal strength to make large parts. Good temperature control can maintain high strength at the geometric inflection point.
application
The polymer blends used in cars include main internal components such as dashboards and seat backs and external components such as baffles, wheel covers and mirror frames.
With the new technology, it is possible to improve the flow characteristics of the special plate number of the vehicle within a wide range of temperature, while maintaining the impact and toughness. Telecommunications and commercial machinery are another major application area. Specific applications include terminal equipment housing, keyboard seat, CATV shell, appliance, and portable mixer. Hair dryer and power tools. The pump room and impeller, as well as the high temperature pipes of the contact fluid, can be made with a PPO based alloy.
Business information
Modified polyphenyl ether alloys can be obtained from GE plastics, whose products are called Noryl and Prevex. They are a PPO - based series of thermal plastics based on PPO. The price tag of the Norvl standard is $1. 38 to $2. 80 / LBS, with a special packing number of $5 / lb. NORYL GTX resin, a PPO/nylon alloy, costs $1. 72 to $2. 70 / lb.
Thermoplastic polyimide.
Several new high-temperature thermoplastic polyimides have been commercialized in the past few years. Thermoplastic polyimide has some advantages over the traditional thermosetting polyimide, and the most remarkable is the ability to improve toughness and heat processing and molding. After the curing reaction of thermosetting polyimide is chemical crosslinking, can't again forming (i.e., the crosslinking), linear polymer and thermoplastic polyimide is fully reflect, containing imide group - CONCO - as part of the polymer chains. Because thermoplastic polyimides have no chemical crosslinking during processing, they can be molded and reshaped.
Chemistry and performance
Since aromatic rings are combined into the polymer framework to bring higher thermal stability, the commercialized thermoplastic polyimide is derived from aromatic diamine and aromatic dianhydride. The preparation of aromatic polyimides usually involves the condensation of aromatic diamine and aromatic dianhydride, which occurs in the appropriate reaction medium and produces an intermediate product polyamide acid. The generated polyamides can be converted into linear thermoplastic polyimide with general structure in some fields or by heat or chemical action.
The main properties of aromatic thermoplastic polyimide are prominent high glass temperature (Tg), significant resistance to high temperature, toughness, good electrical properties, inherent flame retardancy and high radiation resistance. However, due to the relatively high Tg and melt viscosity of thermoplastic polyimide, a relatively high processing temperature is required. In some cases, the processing temperature may exceed the decomposition temperature of polyimide. Although the linear aromatic polyimides, which are processed at temperatures above their thermal decomposition temperature, are theoretically thermoplastic, they are often referred to as pseudo thermoplastic polyimides. In this case, the intermediates of the polyamides, which are more easily dissolved and fused than the final polyimides, may become thin films or moulds before the heat is converted into polyimide. Aromatic polyimide difficult processing problem, to some extent, has been through the double match in the polymer chain and diamine between either or both of the aromatic ring such as acetone, ether and six fluorine vision and propyl groups such as flexible chain and solved. One of the most effective aromatic diamines to improve the processability of thermoplastic polyimide is perfluoroisopropyl diamine (4 BDAF). 4-BDAF and aromatic binary reaction produce polyimide with the structure of the right image.
The thermoplastic polyimides obtained from 4-bdaf are much easier to process than polyimides, which are made from benzodiazepines and aromatic compounds, and still have high Tg and good oxidation thermal stability. The presence of fluorine in 4-BDAF also results in improved electrical performance of polyimide. Other diamines used to improve thermoplastic polyimide processing are aromatic diamines modified with siloxane and diaminobenzene 1, 2-hydrogenindene.
The main characteristic of thermoplastic polyimide is their heat resistance, which is reflected in their high Tg. Is the scope of a typical Tg: from 423 ° F for aromatic polyether imide, some containing 4 - BDAF polyimide of more than 700 ° F.
Compared with thermosetting polyimide, the range of elongation ranges from 5% to more than 50%, and its fracture range is from 8. Raise it to 14 inches [$#8226] / square inch.
Thermoplastic polyimide has excellent electrical properties, and its dielectric constant is less than 2 from the partial fluorinated aromatic polyimide. 8 (1kHz) to non-fluorinated polyimide 3. 5 (1kHz).
With a few exceptions, aromatic thermoplastic polyimide is capable of most ordinary organic solvents and dilute acids. Polyimide is degraded by exposure or immersion in concentrated acids of alkali and heat. Some thermoplastic polyimides are soluble in highly polar organic solvents.
Product form
There are several forms of complete imide thermoplastic polyurethane. Thin film, moulding powder, varnish and fiber supporting film are suitable for mould pressing and injection molding, laminating, electrical insulation and jacket, enameled wire, electric coating, protective coating and adhesives. There are also the prefabricated general profiles of polyimide, which can be machined into various parts.
Made from thermoplastic polyamide intermediate polyamide acid varnish has supply, used in electronic and protective coating and long fiber winding used polyimide acid lacquer, requirements for thermal imide coating or long fiber winding preforming process.
Thermoplastic polyimide can also be made into carbon fiber prepreg to make advanced synthetic materials. The hot type polyimide product also has "dry" thermoplastic prepreg and wet-type prepreg billet. These products are made from a mixture of polyimide monomers which are converted to polyimide network resin during the process of producing composite materials.
processing
Due to the high Tg of aromatic thermoplastic polyimide, high temperature is required to process these polymers.
Polyimide powder can be molded under moderate pressure (21 to 41MPa). According to the thermoplastic polyimide Tg, need to use cast temperature between 500 and 845 ° F to melt the powder. Powder and granule with medium Tg can also be molded by injection molding. Due to high melting viscosity, it is necessary to enrich the professional knowledge for injection molding. In order to optimize the performance of injection molding, it is necessary to follow the procedure recommended by the polyamide supplier for injection molding a special resin.
With the help of traditional film casting technology, the film can be made from polyimide varnish (if it can be dissolved in a suitable solvent) or polyamide acid varnish. If the polyamide acid varnish is used, the film must be thermimide to obtain polyimide film.
Usually, the melt extrusion technique is used because of the high temperature of the aromatic thermoplastic polyimide, which cannot be made into acceptable films. However, it is possible to modify the processing temperature of polyimide by using siloxane diamine or ether modified double face to reduce the processing temperature of polyimide. Thus, the traditional melt extrusion method is feasible.
Impregnated glass, quartz, graphite fiber and/or continuous fiber bundles with polyimide or polyamide solution, then remove the solvent, and heat the resin to melt it to make laminated plates. As with the use of polyamides in other situations, there is a need for a final thermimide process.
The advanced composite materials with high temperature resistance can be prepared from the "wet" or "dry" thermoplastic polyamide preimpregnated billet. The specific polyimide is used to reinforce prepreg and to use polyimide melt. Normally, autoclave temperature over 600 ° F, pressure over 14 mpa. In order to obtain good quality, when making composite materials from thermoplastic polyimide prepreg, it is necessary to comply with the processing conditions recommended by preloading billet suppliers.
False thermoplastic polyimide powder, can use the method of cold forming powder metallurgical technology manufactured components, and then, in 680 to 720 ° F high temperature sintering.
Thermoplastic polyimide is also used in the production of protective coatings for metal and advanced composite materials and the dielectric coating for corrosion barrier coatings and electronic facilities. Usually, polyamide acid varnish is used. Adopt traditional coating techniques (e.g., spray, brush, dip and roll). After a drying step, the polyamide acid coating is converted to polyimide by heat. For thin coatings required in electronic applications, high speed rotary coating processes are used. Similarly, if the polyamide acid varnish is used, a final thermimide process is required in the coating process.
application
Aromatic polyimide is mainly used in aviation and aerospace, navigation, automobile, electrical and electronic industries. The long-term high temperature performance of polyimide meets the needs of these applications.
Aromatic polyimide film is used in electrical insulation of motor, magnetic wire, aircraft and missile and flat soft cable. Due to the inherent barrier properties of aromatic polyimides, thin films are also used to make fire compartments for aircraft and ships. They have excellent radiation resistance and are used in nuclear applications for seat, seal and thermal insulation. Aromatic polyimide bearings, made of moulding and injection moulding, are used in jet engines, appliances and office equipment that require high temperatures and chemicals and natural lubricants. The molded aromatic polyimide is also used as a piston ring for rotary vane compressors, as well as for cars and non-lubricated seals for locomotives on the path.
Advanced composite materials prepared with thermoplastic polyimide are suitable for use in jet engines and advanced military and civil aircraft as primary (structural) and secondary components.
Aromatic polyimide laminate is mainly used in the manufacture of multilayer printed circuit boards. Low dielectric constant, relatively low thermal expansion coefficient (28 to 34 X 10-6 inches/inch / ° F) and strong stick relay with conductive metal, in the most demanding higher replace epoxy resin in electronic purposes.
Coatings based on thermoplastic polyimide are used in the wear and corrosion protection of metal and advanced composite materials. Dielectric coatings obtained from aromatic polyimides are used in semiconductor wafers and high density interconnection (HDI) electronic devices.
Aromatic polyimide foam is used in many aircraft and ships. The low density (< 1 lb/cubic feet = foam) with inherent flame retardants (< 1 lb/cubic feet = foam used in commercial/military aircraft and naval vessels for insulation and acoustic insulation).
Business information
Fake thermoplastic polyimide suppliers are: dupont, the trademark is Kapton (thin film), Vmpel (profile and sintered parts), Pyralin and Pyre ML (paint); Rosers company supplies profile and powder, and its trademark is Envex. The company that supplies the paint has: mon-santo company, which is the Skybond700 American Cysnamid company. The brand name is FM-34, P[$#8226]D[$#8226]George, and the trademark is Untratherm. Albemarle's imi-tech unit is supplying foam with a trademark Solimide.
Thermoplastic polyimide. The supplier of paint and powder is: Rogers company, the trademark is Duramid, Ciba Geigy company, the trademark is Matrimid thermoplastic polyetherimide can be purchased from GE plastics company, its trademark is Ultem. Thermal plastic polyamide curing film have two supply company, they are: dupont, trademark name Avimid, American Cyanamid company, trademark for Cypac. Ethylene/vinyl alcohol copolymer (EVOH) ethylene polymer processability and vinyl alcohol polymer barrier for the combination of ethylene/vinyl alcohol copolymer not only show the excellent processing performance, but also for gas, smell, flavor, such as solvent presents excellent blocking effect. Because of its thermal stability with ethylene, multilayer containers with EVOH barrier layers are fully reusable. It is these characteristics that can replace many glass and metal containers in food packaging with a plastic container containing the EVOH barrier.
Chemistry and performance
Polyvinyl alcohol (PVOH) has the lowest gas permeability in today's available polymers. However, PVOH is water-soluble and difficult to process. The EVOH copolymer is produced in this way: first, ethylene and vinyl acetate copolymer, then hydrolysis of the copolymer to get ethylene - vinyl alcohol. Therefore, the high barrier function is still retained, and there is a significant improvement in moisture protection and processing performance. In nature, the EVOH copolymer is highly crystalline, and its properties mainly depend on the relative concentration of its copolymers. Generally speaking, when the ethylene content increases, the gas barrier property decreases, the moisture resistance improves, and the resin is easier to process. The most notable characteristic of EVOH resin is its blocking effect on gas. It is used in the packaging structure to improve the retention of flavor and quality by preventing the infiltration of oxygen. In the use of inflatable packaging technology, the EVOH resin effectively retains the carbon dioxide or nitrogen used to protect the product. Due to the presence of hydroxyl in the molecular structure of EVOH resin, the EVOH resins are hydrophilic and hygroscopic. When the moisture is absorbed, the barrier properties of the gas are affected. However, the moisture content in the barrier layer can be carefully controlled, and the use of multilayer technology to wrap the EVOH resin layer with strong insulating resin such as polyolefin can do this.
Oil resistant
The EVOH resin also has strong resistance to oil and organic solvents. Under 68 ° F in various kinds of solvent oil and 1 years later, the percentage of weight increase as follows: to cyclohexane, xylene, petroleum ether, benzene and acetone solvent was 0%, the ethylene glycol to 2. 3%, for methanol is 12. 2%, zero for salad oil. 1%. Thermal/mechanical properties <, SPAN lang= en-us >.
The EVOH resin has high mechanical strength, elasticity, surface hardness, abrasion resistance and weather resistance, and has strong antistatic properties. The EVOH film has high gloss and low foggy and is therefore highly transparent.
EVOH resin is all commercial strong barrier resins, the highest thermal stability of resin, the properties of produced in the processing of waste can be recycled and reused, reworked material contains up to more than 20% of EVOH.
processing
There are three basic methods for using EVOH in multilayer structure, and they are: co-extrusion. The EVOH resin is combined with polyolefin or polyphenolamine to form a framework. The film layer is pressed onto other substrates or coated with other materials.
Using EVOH resin as a coating for a variety of substrates or single-layer containers. It is easy to process on traditional manufacturing equipment without special changes.
Using commercial equipment, EVOH resin can be used in the following processing: single or multilayer film extrusion; Extruded sheet and profile; Co-extrusion blow molding; Co-extrusion coating; Lamination (or lamination) and injection molding.
Secondary processing of the EVOH resin frame or EVOH film, such as thermal forming, vacuum forming and printing, is easy to carry out. Like other polymers, the EVOH resin can be modified by overheating.
Coating techniques including multilayer coatings or co-extrusion coatings can also be used to produce multi-layer structures, and the resulting structure is very similar to the co-extrusion structure. It can be sprayed with EVOH resin, immersed or roller coating. The production of carbonated beverage containers or the purpose of blocking solvents, spices, or odors.
The adhesion of the EVOH resin to most polymers is very poor. To overcome this difficulty, a specially designed adhesive resin or "connecting resin" is required. Except for nylon, no adhesive resin is used, and the EVOH resin is well attached to nylon.
The new development
With the growth of rigid and high barrier plastic packaging, new performance requirements are proposed for EVOH resin. To meet these needs, the EVOH supplier provides some brand products, such as the J102 (EVALCA) and the ST series of Goshei. These products improve the machinability and wider range of molding. Other products, such as the F100 and E151 of EVAL, are also developed with better viscosity and better compatibility with the typical polyolefins used in rigid containers.
In the field of plastic recycling, EVOH resin is more advantageous. Used high density polyethylene milk bottles and multilayer bottles (containing EVOH resin) are used to produce containers for non-food use.
application
The barrier structure containing the EVOH resin is used in all kinds of hard and soft packaging and all types of food processing including sterilization, heat injection and pressure cooking. Products packed with EVOH materials include: seasoning (soy sauce), tomato sauce, juice, edible batter, meat products, cheese products and processed fruits.
Non-food applications include solvents, chemicals and product packaging related to pharmaceuticals.
Manufacturers of vehicle fuel tanks, fuel pipes and air-conditioning equipment are evaluating the use of the EVOH structure to reduce hydrocarbon and/or freon emissions.
Business information
Suppliers include Nippon Goshei, Japan's Kuraray co., and American EVAL inc.
Ethylene-acrylate (EMAC)
Ethylene-acrylate copolymer (EMAC) is one of the best thermal stability of all high - pressure alpha olefin copolymer. The EMAC is used as a single material or blending material. Molding, blow molding, extruding and extrusion molding and co-extrusion have many applications. It can be added more than 50% of the packing without affecting its elasticity, and can be compatible with all polyolefin resin and can be used as matrix resin for the parent material.
Chemistry and performance
The EMAC is produced by a normal high pressure reactor, and the acrylic monomer and the ethylene gas are sprayed into the reactor to produce a random copolymer. The commodity EMAC contains 18 ~ 24% (wt) of acrylate, and the melting index value of commercial materials is 0. 5- 20 g / 10 minutes. Some of the specifications are pure resins, while others contain smooth and antibonding ingredients. In order to improve its processing performance and softness. Adhesion properties, other formulations are being developed. EMAC copolymer during the most remarkable performance improvement (compared with LDPE homopolymer) include: d CARDS, Vicat softening temperature decreased from 194 ° F to 194 ° F. The bending modulus decreases; The performance of environmental stress fracture is improved remarkably. Dielectric performance is enhanced. This kind of material has good resistance to most chemicals, but is not designed as a continuous immersion in organic solvents and nitric acid.
processing
With a standard of LDPE film extrusion line, at about 325 ° F melting temperature, it is easy to blow the EMAC processed into during the film. Blown film has extremely high impact strength, and it is very easy to heat and weld using traditional heat fusion equipment or RF method (RF). The same kind of material can put glue in the conventional extrusion temperature 600 ~ 620 ° F extrusion under post adhesive glue or coextrusion. The temperature of the flow film, injection molding and blow molding is in the above temperature range, which shows that the processing performance of ethylene methacrylate copolymer is very high.
The film has the flexibility of latex rubber, suitable for disposable gloves and some medical supplies.
use
According to FDA and USDA regulations, EMAC meets the requirements of food packaging. EMAC has also been recognized as a hot seal and food surface contact material in the use of the aseptic packaging of the hydrogen peroxide sanitizer. Such materials also meet the VI standard requirements for medical use of USP. The EMAC resin does not release unpleasant substances, such as halogens, during incineration.
The surface turbidity of EMAC films is higher than that of the typical polymer LDPE. This feature, along with the softness of its latex rubber, makes it ideal for disposable gloves and some medical supplies.
EMAC is a good extruded adhesive and extruded laminated resin. This is due to its natural good thermal stability, adhesion to common matrix, thermal fusion and rf welding performance, and can be machined on a device designed for LDPE.
In order to form a hot fusion layer on the substrate, the ring and planar thin film die are extruded. It is used as the bonding layer, and the laminated adhesiveness of polyolefin, depolymerization, polyester, polyurethane, EVA, PVDC, EAA, OPET, OPP and so on.
The hoses and profiles have excellent resistance to stress fracture and low temperature impact strength. Foam sheet can be used for meat or food packaging.
EMACN used with LDPE, polypropylene, polyester, nylon and polycarbonate blending component, in order to improve the impact strength and toughness, to enhance thermal performance, improve the adhesive properties, reduce stiffness and increasing surface friction coefficient.
Impact polystyrene.
The production of polystyrene began in 1930, and was one of the first thermoplastic polymers of industrial production. In order to meet the requirements of ductile materials, rubber modified polystyrene (HIPS) was developed in 1950. High impact polystyrene with different properties can be produced by adding rubber to polystyrene substrate. In recent years, has developed a variety of special grade of HIPS, existing flame retardant, resistance to stress cracking, high gloss, high impact strength, glass fiber reinforced level, and low residual volatile grading, etc., they are in many application areas have been able to compete with expensive engineering resins.
The characteristics of anti - impact polystyrene are easy to process, high dimensional stability, high impact strength and high rigidity. HIPS are just heat resistant. There are certain limits in oxygen permeability, uv stability and oil resistance. Chemistry and performance
The impact polystyrene is made by mixing the polydiene rubber in the styrene monomer prior to polymerization. Although HIPS can be used in suspension polymerization, HIPS are currently produced in industry mainly by bulk polymerization. In the process of bulk polymerization, a mixture of styrene monomer/rubber/additive is obtained through a series of reactors with a conversion rate of 70 ~ 90%.
In the polymerization reaction, it is necessary to heat or add the initiator to complete the reaction, and then in the vacuum, the volatile residual monomer is removed from the resin, and then the granulation is sold. Anti-impact polystyrene is divided into several levels according to its relative impact strength: the impact strength of the gap cantilever beam with medium impact grade is generally 0. 6-1. 5 ft. Lb/in; The impact degree of high impact resistance is 1. 5-2. 5 ft. Lb/in. The impact strength is > 2. 5 ft. Lb/in. Some HIPS have an impact strength of up to 6. 0 ft. Lb/in, but this resin is usually used in blends to enhance the impact of low - strength grade resin.
Other important properties of the standard HIPS are: bending strength 13. 8 ~ 55. 1 mpa; Tensile strength 13. 8-41. 4 mpa; The elongation at break is 15-75%; Density of 1. 035-1. 04 g/ml; Vicat softening point 185-220 ° F. The only industrial mixed HIPS alloy is its blend with polyphenyl ether. This blend is resistant to heat and toughness.
However, products are much higher than HIPS (see "alloy and blend" P15).
The continuous development of polystyrene technology enables the production plant to produce more outstanding quality grades than the standard PS. Many of the properties of polystyrene can not be combined, and if you want to increase the impact strength, you have to sacrifice the gloss. Some of the new types of resins that are present, they have the gloss of ABS, and also have high toughness. Some grades, such as the ability to tolerate a variety of fats and oils as well as the use of CFC foaming agents for refrigerating machines, have been developed. Flame retardant grade (UL V-0 and UL 5-V), anti - impact polystyrene has been produced and widely used in television case, commercial machine and electrical products. These resins are easier and cheaper to process than many flame-retardant engineering resins.
processing
The anti-impact PS can be processed by many traditional molding methods, such as injection molding, structural foam molding, sheet and film extrusion, thermal molding and injection molding, etc. HIPS resins absorb water more slowly, so they generally do not need to be dry. Sometimes too much water on the surface of the material will be absorbed, which will affect the appearance quality of the final product. Drying under 160 ° F for 2-3 h to remove excess water.
The extrusion of thin film, sheet and profile is the most suitable processing method for HIPS. The impact polystyrene has a wide range of processing, so it is one of the most easily formed resins. General use common extrusion equipment resin melt temperature is 400-500 ° F, the melt index of the resin range is 1. 5 to 4. 0 g / 10 min. Rotary, series and shuttle pressure and vacuum thermoforming equipment are also often used. HIPS has excellent thermal stability and shear stability, and can be used for multiple recovery materials without reducing the product performance. The amount of recycled materials used in hot forming process can reach up to 60%.
Injection molding is the most widely used processing method after extrusion. Resin injection molding is generally in the length ratio of 16:1-24:1, compression ratio is 2. 5/1-3. 0/1 reciprocating screw injection molding machine. Processing temperature 350-500 ° F, but for the flame retardant grade HIPS, its processing temperature must be lower than 470 ° F, in order to prevent the additives in the degradation reaction. The melt index of resins processed by injection molding is generally 5. 0 ~ 15. 0 g/min. Structural foam forming method is a common process, using chemical and physical foaming agent.
Despite all kinds of HIPS resin are compatible, but before operation to clean processing equipment, to ensure product quality, good resistance to impact of PS and propylene eyes yiding Th a styrene copolymer (ABS), polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), acrylic resin, and most other plastic are incompatible, incompatible plastic mixture in the processing equipment can produce separation delaminating phenomenon, cause physical performance greatly.
application
The anti-impact PS is easy to process, good performance and low price, so it is used to make many kinds of products and industrial products. The main applications are packaging and disposable products, instrumentation, household appliances, toys and entertainment products and construction industries.
HIPS's biggest use is for packaging and disposable materials, especially food packaging materials and eating utensils. The main applications include daily packaging containers. The vending machine USES and distributes cups, covers and plates. Bowl and so on. Disposable products such as disc, bottle cap, safety razor, pen, etc. Are also a large part of the use of HIPS consumption.
In recent years, special products have been the focus of HIPS product development. New development of the HIPS products in some application fields can compete with engineering resin, some was much higher than the current quality of the products, instruments and consumer electronics is one of the HIPS products growing market, including small instrument, refrigerator inner surface and internal parts, TV shell, air-conditioning unit, business machines and recording video cassette. The special grade HIPS resin has replaced the high-priced engineering plastics in many fields, with a high impact strength and high temperature HIPS that can even be used as car interior parts.
Business information
In 1992, HIPS resin production was about 27/100 million lb, almost half of the total output of PS. In the United States, the impact of PS has seven major producers: Amoco, Chevron, Dow, Fina, Huntsman, BASF and Novacor impact polystyrene standard price is 40 a 50 cents/lb, in terms of moulding and extrusion, and engineering plastics and plastic goods (such as polyolefin resin, PVC, etc.), compared to its price/performance is good, this is the advantage of it.
PPS
Polyphenylene sulfide is a semi-crystalline material with excellent properties of high temperature resistance, chemical resistance, fluidity, dimensional stability and electrical properties. This material can be filled with reinforced fibers and fillers for injection molding.
Chemistry and performance
Polyphenylene sulfide (PPS) is made from 1,4 dichlorobenzene and sodium sulfide in polar solvents.
After the beginning of the process, the material is cooked at high temperature, and the high viscosity material is partially branched, which is suitable for the processing of thermoplastic plastics.
Various companies have been able to eliminate this maturation period and make the material have a normal linear PPS structure. Now there are two forms of PPS in the market: one is characterized by partial branching structure; The other is a relatively linear PPS structure. The latter product has better mechanical strength and higher melt stability.
As PPS melt viscosity is low, it can load up to 70% of various fillers and enhancers. Different fillings change the strength, electrical properties, surface performance and dimensional stability of the material, as well as the cost of the mixture. Hot melting temperature of around 545 ° F PPS, can withstand the test of 500 ° F in the short term. In 1. Under the load of 82MPa, the thermal deformation temperature of PPS is generally higher than 500T, and the upper limit temperature also depends on the stress.
Due to the chemical structure of PPS, 70% of aromatic compounds and 30% of sulfur are naturally flame retardant. When the material is recycled, its flame retardant performance will not be affected. The minimum oxygen concentration required to maintain the continuous combustion of PPS samples is more than 40 percent. In normal circumstances, only about 22 percent of the oxygen in the atmosphere is not enough to sustain PPS combustion. Made of PPS material components can be resistant to corrosive chemical environment: in less than 400 ° F, known solvents can dissolve it. However, PPS cannot be used in oxidizing acids for long periods of time, such as hot nitric acid. In addition, PPS does not absorb moisture, which is different from nylon, polyethers and polyesters.
processing
PPS injection tooling generally USES the traditional injection molding machine screw type, heating zone temperature range is 600 a 680 ° F. The injection pressure is generally between 55MPa and 83MPa, and the specific value shall be determined according to the component design and the mixture of PPS. The high turnover rate of PPS can be filled with long and thin sections.
Before processing, the material should be in dehydration drying oven dry 3-4 hours, the drying temperature of 300 ° F. If necessary, cheng fang to 2 inches deep plate, drying with the traditional heating furnace 2, 4 hours, the temperature is 300-350 ° F. PPS that are not thoroughly dried will not affect the homogeneity of the parts, but will cause trouble during processing. In the injection molding machine barrel, the moisture that is assembled in the mixture is turned into steam, which causes the nozzle of the injection molding machine to flow.
The temperature of the mould must be controlled precisely because of the high thermal stability of PPS. The mold temperature is between 275-325t and the material can be crystallized. Below this range, the components may or may not be crystalline. If the part is not fully crystalline and is used at a temperature higher than the original mold temperature, the component will begin to crystallize.
It is not desirable that parts shrink when they are out of the mold. Even if a component is only used for non-thermal chemical processes, the high mold temperature is also important, because the surface of the parts that are machined under the high mold temperature is smooth and is "rich resin". For a cold molded part, the packing tends to move towards the surface and is vulnerable to chemical attacks. The parts of the die subjected to high shear stress should be hardened steel, which is due to the high content of the filler and the wearability of the packing.
application
Because PPS materials have high thermal deformation temperature (HDT) and flame retardant properties, and can fill long and thin sections, its primary purpose is to make electrical connectors and electrical components. For an electrical fittings, generally do not need resistance to high temperature of 500 ° F, then why need to high heat deformation temperature (HDT)? Here, the connection between the connector and the printed circuit board is the key. With the use of the new united method, such as infrared and vapor phase of consolidation consolidation, materials have to undergo the actual temperature as high as 450 ° F, PPS at such a high temperature to maintain its stiffness, make the insert fitting the nail surface not loosen.