Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
PPA plastic in Chinese: high temperature resistant nylon PPa has a heat deformation temperature of more than 300буC, and the continuous use temperature can reach 170буC, which can meet your short-term and long-term thermal performance requirements.
Maintains its excellent mechanical properties - strength, hardness, fatigue resistance and creep resistance in a wide temperature range and high humidity environment. Toughened grade PPA combines excellent toughness with a certain range of hardness and flexibility, and is a good choice for fasteners that require rigidity for one-time use and flexibility in repeated use
Polyphthalamide (PPA for short) resin is a semi-aromatic polyamide based on terephthalic acid or phthalic acid. There are both semi-crystalline and non-crystalline states, and its glass transition temperature is around 255буF. Non-crystalline PPA is mainly used in occasions requiring barrier properties; semi-crystalline PPA resin is mainly used for injection molding, and is also used in other melt processing processes. The following mainly introduces the latter - semi-crystalline PPA resin, unless otherwise specified. Semi-crystalline PPAS has a melting point of about 590буF and is supplied in opaque rectangular slices.
PPA resins are stronger and harder than aliphatic polyamides such as nylon 6,6; they are less sensitive to moisture; they have better thermal properties; and they have much better creep, fatigue, and chemical resistance. For example: PPA resin containing 45% glass short fibers has a tensile strength of about 276MPa, a flexural modulus of more than 13786MPa, and a heat distortion temperature (HDT) of 549буF. Even mineral-filled grades of PPA have a tensile strength of 117MPa. PPA resins are not as ductile as nylon 6,6, however, unreinforced impact-modified grades of PPA resins have been developed with notched Izod impact strengths of up to 20 ft.-lbs/in.
All polyphenolamines absorb a certain amount of moisture, causing plasticization and dimensional changes. For example, nylon 6,6 can absorb 8.9% water at 23буF and 100% relative humidity, which reduces its glass transition temperature from 6.5буC to -20буC and increases its size by 2.3%. Under the same conditions, PPA resin can absorb about 6% water, but its glass transition temperature Tg will not fall below 40буC, and the accompanying size growth does not exceed 1.0%.
As mentioned earlier, glass-reinforced PPA resins have high HDT values and can withstand short-term effects of very high temperatures, such as in a furnace or in the steam phase and in infrared countercurrent polymerization processes. The thermal oxidative stability of PPA resins enables it to withstand long-term high temperature effects. Glass-reinforced PPA can be used continuously at temperatures of up to 330буF for 20,000 hours.
Under normal environmental conditions, PPA resins generally exhibit excellent resistance to aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, esters, ketones, alcohols and most aqueous solutions. This type of resin cannot withstand the effects of extremely strong acids and strong oxidants. Soluble in phenol and cresol. PPA is not inherently flame retardant. According to the UL94 standard, flame retardant grades of resin are rated as VO up to 0.031 inches thick.
Although other melt processes can also be used, most PPA resins are processed by traditional injection molding. Pre-dry the PPA raw material to a humidity level below 0.1% and then pack it into heat-sealed metal bags or boxes. These containers ensure that the PPA raw material does not need to be dried again before processing. The acceptable humidity level for processing is 0.15% or lower. Processing wet resin can reduce molecular weight and cause corresponding loss of mechanical properties. Using a desiccant hopper dryer, it is easy to dry the resin to a dew point humidity of -25буF or even lower at 175буF. The drying time depends on the amount of water absorbed and is generally in the range of 4-16 hours.
During injection molding, the melt temperature is in the range of 615-650буF, and the residence time of the material in the barrel does not exceed 10 minutes, so that the mechanical properties of the injection molded product are the best. The mold temperature is required to be at least 275буF in order to obtain a product with complete crystallization and optimal dimensional stability. Parts with thick walls can be injected at lower mold temperatures due to slow cooling. Mold temperature is critical to optimizing the surface appearance of the finished part. The mold surface temperature of mineral filler grade PPA resin used for vacuum metallization into electroplated metal requires 350буF.
Due to the outstanding physical, thermal and electrical properties of 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. The trend towards better aerodynamic body design together with higher performance motors will increase the temperature of the engine box, making traditional thermoplastic not entirely suitable. These new requirements make PPA one of the candidate materials for the following parts: automotive headlight reflectors, bearing seats, pulleys, sensor housings, fuel line components and electrical components.
The development direction of electrical components is miniaturization and high-temperature bonding, such as infrared bonding and vapor phase bonding, which requires the superior performance of PPA. Flame retardant PPA has excellent electrical properties, high HDT value, high high temperature flexural modulus, and can be processed into long thin-walled parts with minimal flash, so it is suitable for making switchgear. Connectors, brush holders and motor brackets.
Mineral filler grade PPA is used for reflective surfaces and metal plating, including automotive headlights, decorative pipes and hardware. Unreinforced impact modified grade PPA has excellent balanced mechanical and high temperature properties. Extraordinary toughness and these properties are minimally affected by humidity. Its uses include oil field components, military supplies, sporting goods, fan impellers and gears and personal safety products.
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