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Changshu smoothly da plastic products factory about the factors affecting plastic material impact strength
by：CSSSLD
2021-01-23
Low temperature impact strength is an important basis of judge plastic material, and the factors influencing low temperature impact strength of PVC plastic profile with multiple factors, such as formulation, section structure, mould, plasticizing degree, test conditions, etc.
Changshu well below da plastic products factory about the factors influencing low temperature impact strength of PVC plastic profile five!
1, the formula of
now widely use CPE as impact modifier, the chlorine mass fraction of 36% of CPE on PVC modified effect is best, dosage in 8 - commonly 12 quality, low crystallinity and glass transition temperature, good elasticity and the compatibility with PVC.
2, the structure of the section
high quality PVC profile with good cross section structure. Normally, the structure of the small cross section is better than that of the structure of large cross section, the section on the location of the inner ribs appropriate to set up. The thickness of the increase in muscle, joint, muscle and wall using circular arc transition, all help to improve the impact strength at low temperature.
3, mold
mold influence on low temperature impact strength is mainly manifested in the stress of the melt pressure and cooling control. Once the formula to determine, the melt pressure mainly related to the mouth mould. Out of the mouth mould material through different ways of cooling, can make a difference in stress distribution. Stress concentration place PVC impact strength at low temperature is poor. PVC is quenching are prone to stress, so the stock mould cooling water flow channel layout is critical, general control in 14 ℃ - water temperature 16 ℃, adopts the slow cooling method to improve the low temperature impact strength of PVC profiles.
the best state of moulds, regular cleaning mode, to avoid long time continuous production and the impurities clogging mode, resulting in a decrease of discharging, support bar too thin, affect the impact strength at low temperature. Regular cleaning stock mould can guarantee enough stock mould shape vacuum degree and water flow, to ensure that the material is cooled sufficiently in the process of production, reduce the defects, reduce internal stress.
4, plasticizing degree
a lot of research and test results show that the low temperature impact strength of PVC profile is the best value in the plasticizing degree is 60% 70% when available. Experience has shown that & other; High temperature and low speed & throughout; And & other Low temperature high speed & throughout; To get the same plasticizing degree. But the preferred low temperature high speed in production, because of low temperature can reduce the heating power consumption, high speed and can improve the efficiency of production, and twin screw extruder high-speed shearing action obviously when it is squeezed.
5, test condition
GB/T8814 - In 2004 has strict rules to the low temperature impact test, such as the length of the plastic material, quality of drop hammer, hammer head radius, sample freezing conditions, test environment, etc. , in order to make the test results are accurate, we will strictly abide by the rules.
1, the formula of
now widely use CPE as impact modifier, the chlorine mass fraction of 36% of CPE on PVC modified effect is best, dosage in 8 - commonly 12 quality, low crystallinity and glass transition temperature, good elasticity and the compatibility with PVC.
2, the structure of the section
high quality PVC profile with good cross section structure. Normally, the structure of the small cross section is better than that of the structure of large cross section, the section on the location of the inner ribs appropriate to set up. The thickness of the increase in muscle, joint, muscle and wall using circular arc transition, all help to improve the impact strength at low temperature.
3, mold
mold influence on low temperature impact strength is mainly manifested in the stress of the melt pressure and cooling control. Once the formula to determine, the melt pressure mainly related to the mouth mould. Out of the mouth mould material through different ways of cooling, can make a difference in stress distribution. Stress concentration place PVC impact strength at low temperature is poor. PVC is quenching are prone to stress, so the stock mould cooling water flow channel layout is critical, general control in 14 ℃ - water temperature 16 ℃, adopts the slow cooling method to improve the low temperature impact strength of PVC profiles.
the best state of moulds, regular cleaning mode, to avoid long time continuous production and the impurities clogging mode, resulting in a decrease of discharging, support bar too thin, affect the impact strength at low temperature. Regular cleaning stock mould can guarantee enough stock mould shape vacuum degree and water flow, to ensure that the material is cooled sufficiently in the process of production, reduce the defects, reduce internal stress.
4, plasticizing degree
a lot of research and test results show that the low temperature impact strength of PVC profile is the best value in the plasticizing degree is 60% 70% when available. Experience has shown that & other; High temperature and low speed & throughout; And & other Low temperature high speed & throughout; To get the same plasticizing degree. But the preferred low temperature high speed in production, because of low temperature can reduce the heating power consumption, high speed and can improve the efficiency of production, and twin screw extruder high-speed shearing action obviously when it is squeezed.
5, test condition
GB/T8814 - In 2004 has strict rules to the low temperature impact test, such as the length of the plastic material, quality of drop hammer, hammer head radius, sample freezing conditions, test environment, etc. , in order to make the test results are accurate, we will strictly abide by the rules.
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