Material selection and formula design
DATE：2019/12/6 8:59:43 / READ： / SOURCE：This station
1. Material selection and formula design
Because PVC has poor thermal stability, poor processing fluidity, and great brittleness, stabilizers, lubricants, modifiers, and other auxiliaries should be added to the formula to ensure its smooth processing and sufficient toughness.
(1) Selection of materials
1) PVC. Water supply UPWC pipes should meet sanitary requirements and have certain mechanical strength. Therefore, PNC must meet sanitary standards, and its vinyl chloride monomer content should be less than 5 × 10-6, and its degree of polymerization is preferably 900-1000.
2) Stabilizers and lubricants. Stabilizers and lubricants are added to ensure that UPVC has good stability and lubricity during processing. Adjusting the reasonable ratio between stabilizers and between stabilizers and lubricants can ensure the normal production and performance requirements of UPVC pipes. At present, many domestic manufacturers use composite stabilizers, such as Germany's Bear brand stabilizers, Japan's Mizusawa company stabilizers, etc., whose performance can meet production requirements, and can ensure the hygienic requirements of UPVC pipes. The use of composite stabilizers can reduce batching errors, reduce dust, and improve environmental conditions during the batching process.
3) Modifier. PWC pipe has poor impact resistance, and its processing fluidity is not good. Adding a modifier is the most direct and effective method to improve the UPVC processing fluidity and its toughness. CPE, ACR, MBS are generally used as modifiers in the production of UPVC water supply pipes. ① CPE modifier. The modification effect of CPE as a modifier depends mainly on the molecule
The chlorine content within the range is preferably between 32% and 40%.
② ACR modifier. The toughening effect of ACR as a modifier is mainly determined by the content of co-dye propylene n-butyl ester. The larger the content, the better the toughening modification effect.
③MBS. The toughening effect of MBS as a modifier is mainly determined by the content of rubber phase II. The larger the content, the better the toughening effect, but the worse the compatibility with PVC resin.
(2) The effect of modifier on the processing performance and mechanical properties of UPVC pipe 1) The effect of modifier on the processing performance of UPVC pipe. In actual application
Now: CPE has little effect on UPVC processing, MBS can improve UPVC processability
After entering ACR, it can significantly improve the processability of UPVC. Its processing temperature is 5-8 ° C lower than the heating temperature of pure UPVC, and the surface of the produced pipe is smooth. If a methyl methacrylate copolymer is used, PC has better processing fluidity. This is because PVC / ACR is a better compatible system. The adhesion between the two interfaces is relatively large. Under certain conditions, a relatively high friction force is generated, which prevents the relative slippage between the surfaces in a short time. The internal particles are stretched and broken to form a more uniform melt, which improves the plasticizing properties of UPC and is easy to shape and process.
2) The effect of modifiers on the mechanical properties of UPVC pipes. The effect of modifiers on the mechanical properties of UPVC pipes is shown in Table 1-25
Because PVC has poor thermal stability, poor processing fluidity, and great brittleness, stabilizers, lubricants, modifiers, and other auxiliaries should be added to the formula to ensure its smooth processing and sufficient toughness.
(1) Selection of materials
1) PVC. Water supply UPWC pipes should meet sanitary requirements and have certain mechanical strength. Therefore, PNC must meet sanitary standards, and its vinyl chloride monomer content should be less than 5 × 10-6, and its degree of polymerization is preferably 900-1000.
2) Stabilizers and lubricants. Stabilizers and lubricants are added to ensure that UPVC has good stability and lubricity during processing. Adjusting the reasonable ratio between stabilizers and between stabilizers and lubricants can ensure the normal production and performance requirements of UPVC pipes. At present, many domestic manufacturers use composite stabilizers, such as Germany's Bear brand stabilizers, Japan's Mizusawa company stabilizers, etc., whose performance can meet production requirements, and can ensure the hygienic requirements of UPVC pipes. The use of composite stabilizers can reduce batching errors, reduce dust, and improve environmental conditions during the batching process.
3) Modifier. PWC pipe has poor impact resistance, and its processing fluidity is not good. Adding a modifier is the most direct and effective method to improve the UPVC processing fluidity and its toughness. CPE, ACR, MBS are generally used as modifiers in the production of UPVC water supply pipes. ① CPE modifier. The modification effect of CPE as a modifier depends mainly on the molecule
The chlorine content within the range is preferably between 32% and 40%.
② ACR modifier. The toughening effect of ACR as a modifier is mainly determined by the content of co-dye propylene n-butyl ester. The larger the content, the better the toughening modification effect.
③MBS. The toughening effect of MBS as a modifier is mainly determined by the content of rubber phase II. The larger the content, the better the toughening effect, but the worse the compatibility with PVC resin.
(2) The effect of modifier on the processing performance and mechanical properties of UPVC pipe 1) The effect of modifier on the processing performance of UPVC pipe. In actual application
Now: CPE has little effect on UPVC processing, MBS can improve UPVC processability
After entering ACR, it can significantly improve the processability of UPVC. Its processing temperature is 5-8 ° C lower than the heating temperature of pure UPVC, and the surface of the produced pipe is smooth. If a methyl methacrylate copolymer is used, PC has better processing fluidity. This is because PVC / ACR is a better compatible system. The adhesion between the two interfaces is relatively large. Under certain conditions, a relatively high friction force is generated, which prevents the relative slippage between the surfaces in a short time. The internal particles are stretched and broken to form a more uniform melt, which improves the plasticizing properties of UPC and is easy to shape and process.
2) The effect of modifiers on the mechanical properties of UPVC pipes. The effect of modifiers on the mechanical properties of UPVC pipes is shown in Table 1-25
Author：admin