The weather resistance of PVC profiles is an important performance indicator. Its level is related to the weather resistance of PVC profiles. Recently, two technologies introduced abroad are worth learning from. The introduction is as follows:
Improving weather resistance of pvc profiles with nano-scale cerium oxide
In the past, in order to improve the weather resistance of PVC profiles, UV absorbers such as benzophenone and benzoxazole were added to the vinyl chloride lamp resin. But due to UV absorbers. Because the UV absorber is easily volatilized under the action of light and heat, it deteriorates, and it is difficult to maintain high weather resistance for PVC building materials for a long time. In addition, degraded UV absorbers can impair the transparency of PVC building materials. And in the mixture of vinyl resin, stabilizer, lubricant, processing aid, modifier, plasticizer, filler, antioxidant and ultraviolet absorber, add nano-cerium oxide or use it to replace ultraviolet absorber, It can greatly improve the weather resistance of PVC building materials, so that it can maintain good mechanical strength and transparency for a long time.
For example, take 100 parts of polyvinyl chloride (flat degree of polymerization 1030), 3.9 parts of organic tin stabilizers, 0.5 parts of fatty acid calcium, 1.0 parts of acrylate, 5 parts of methylpropionate-butadiene-stupid ethylene modifier, Add 1.0 part of cerium oxide with a particle size of 6nm to the mixture composed of 0.2 parts of polyethylene wax, place it in a mixer to mix, and then place it in a double-roll mill to mix at 180 ° C for 3 minutes to make a 1mm thick cerium oxide. flakes. The sheet was compounded, preheated at 180°C for 3 minutes, pressed at 5 mPa pressure for 4 minutes, and made into a test piece with a thickness of 2 mm. The transparency was measured with a colorimeter and a moonlight carbon rod arc irradiation respectively. and hue changes. The results show that the use of nano-cerium oxide as the most substitute for ultraviolet absorbers, the weather resistance is significantly improved, and the transparency and color tone remain basically unchanged for a long time.
Improving weatherability of pvc profiles with mixed titanium oxide
Using titanium oxide can improve the weather resistance and hiding power of PVC building materials, prevent fading, and is easy to color. This titanium oxide is commonly used in PVC building materials. However, currently only one of the rutile type anatase type titanium oxides is added to the vinyl chloride resin-based mixture, and the weather resistance cannot be sufficiently improved. The degree test shows that the mixed titanium oxide composed of rutile type and anatase type titanium oxide with a ratio of 1.3:1 added to the vinyl chloride resin as the base material can give full play to the role of titanium oxide and further improve the weather resistance and durability. Covering power and preventing fading are also better.
For example, the color tone of the PVC specimen containing only 0.54 parts of rutile-type titanium oxide will change after being irradiated by the aging tester for 200 hours, while the mixed titanium oxide composed of 0.54 parts of rutile-type and anatase-type titanium oxide is composed of mixed titanium oxide. The color tone of the PVC specimen remains unchanged after being irradiated by an aging tester for more than 600 hours. In addition, compared with the technology group that incorporates expensive resins and admixtures to improve weather resistance, the technology of mixing titanium oxide has lower production costs.
The above two technologies are simple and feasible, suitable for the production of PVC profiles