PVC internal & external lubricant
Organic Matting Agent
Shandong Dingding Chemical Co., Ltd.
Add:No.292 Weigao Road Gaoqing Zibo,Shandong China
Application of PVC_ACR low temperature impact modifier
PVC plastic doors and windows due to its excellent insulation, noise reduction, sealing and other characteristics, which has been widely used. Especially in cold areas of northern China and areas prone to sandstorms, more fully demonstrated the incomparable superiority. However, PVC plastic windows after years of use also revealed some weaknesses, such as low temperature impact resistance, cracking, aging discoloration and other issues.
Application of Impact Modifier at Home and Abroad
Since the introduction of PVC plastic door and window manufacturing technology in the 1980s in our country, the impact modifier is mainly based on CPE, and our country's production capacity is strong, the output is large, there is a trend of oversupply. Therefore, the domestic production of PVC plastic window profiles using CPE as an impact modifier is very common. Due to the fierce competition in the market for the production of CPE, individual manufacturers have won in quantity and neglected the quality of their products, affecting the stability of the product quality of some PVC window profiles manufacturers. Such as the thermal deformation temperature drops, the process is unstable, impact performance due to the quality of CPE fluctuations, a direct impact on the PVC plastic window quality. Although many professional and technical personnel have noticed in the formula design PVC low temperature impact resistance and other issues, but always around CPE as a modifier to improve low temperature impact resistance, so the actual effect is not obvious. With the progress of technology, the emergence of a new domestic impact modifier ACR, the trial has obviously improved the PVC plastic window low temperature impact resistance and other issues. After 90 years, with the increase of production of acrylic acid ester (ACR) in our country, the cost will drop, which will make more PVC plastic window profile factory adopt. The superiority of ACR shows more and more the effect of improving low temperature impact resistance of PVC, reducing cracks and improving aging discoloration. At present, the impact modifiers used in foreign countries, especially in Europe, are mainly ACRs, which are obviously superior to CPEs and other modifiers. Therefore, the application of ACR is an important way to improve and improve PVC plastic window performance.
Impact modifier selection
The choice of impact modifier should pay attention to the following aspects:
1, compatibility with PVC resin should be moderate, if the compatibility is too large, two completely molecular mixture, impact modifier may play a role as a plasticizer, and PVC molecules are closely attached, leaving the impact Force directly on the PVC chain, can not improve the role of anti-impact. On the contrary, if the compatibility between the two is too small to achieve uniform dispersion, the adhesion to PVC is lost and the impact can not be absorbed.
2, the glass transition temperature is low, can improve the impact resistance of PVC at low temperature.
3, high molecular weight, if necessary, the best light cross-linked to enhance the enhancement effect.
4, the performance of PVC performance and physical properties had no significant impact.
5, weatherability should be good, small mold expansion.
6, good blends with PVC technology.
7, heat resistance (resistant to deformation, thermal stability) is better.
Properties and Application of Acrylic Series Impact Modifier
As acrylate is a "core-shell" structural elastomer, giving it a series of advantages:
Excellent impact resistance
The impact resistance of "core-shell" structure is better than network structure polymer (CPE, EVA). As far as the glass transition temperature is concerned, the CPE is -10 ° C to -20 ° C, while the acrylate is up to -56 ° C, so that the low-temperature impact performance is obviously superior to that of CPE. The latest development of the TAE-858 glass temperature up to -60 ℃ above, to improve the profile low temperature impact performance is significant.
A wide range of processing technology, operation process and stability
CPE processing temperature range is narrow, because the structure of PVC and PVC close, high temperature (185 ℃), good mixing, easy to damage the network structure, resulting in decreased impact resistance. If the temperature is low, poor plasticization, poor dispersion, but also affect the impact, appearance and other properties, and acrylic impact modifier does not exist the above problems, processing temperature is wide, easy to operate, high yield, stable production Good sex.
Lower thermal shrinkage, dimensional stability
Good use of ACR impact modifier P V C profiles generally 100 ℃, 60 minutes lower shrinkage, usually below 1.5%. The CPE is higher, generally more than 1.5% (standard requirements ≤ 2.5%). The practical significance of this project is to test the longitudinal stress of PVC profiles. The factors affecting the size of longitudinal stress are the degree of plasticizing gel and the speed of the process traction. As a result, the residual stress between molecules is too large, and the local is more concentrated, which is the main reason for the stress cracking of PVD profile. The use of ACR impact modifier to improve the profile of the stress cracking has a significant role in the low temperature assembly cracking less.
Suitable for high-speed profile extrusion, and the role of flow modifier
ACR impact modifier physical structure is reasonable, so a wide range of processing, extrusion speed, to adapt to the higher shear rate, suitable for high-speed extrusion. Low melting temperature, and good fluidity, can save A C R flow modifier, reduce costs.
Product surface gloss is good
Due to ACR easy plasticization, low melt strength, high degree of gel, so the product surface gloss. Experiments show that modified with CPE, the general gloss of 20% to 40%, and after the use of A C R modified, the gloss can reach 40% to 65%, the product is smooth and delicate, feel good.
Improve the welding strength
As the ACR after the application of improved plasticizing properties, so that the performance of the PVC profile body, the other due to a wide processing temperature, adaptability and improve the welding strength, thus significantly improving the strength of the welding.
Improve the weather resistance of PVC profiles
At present, the use of CPE impact-resistant PVC profiles have varying degrees of gray, yellow phenomenon, which has a direct relationship with the CPE. The whiteness of CPE changed greatly after irradiation with ultraviolet light, reaching 50%, while the change of ACR was only 30%. So seriously affect the appearance of PVC profiles color change. Using A C R is an important way to improve weathering and anti-aging properties.