Plasticizer varieties used in PVC blown film

plasticizer varieties for PVC blown film

plasticizer varieties for commonly used blown film are benzene dimethyl dioctyl ester (DOP), Petroleum sulfonate, dibutyl phthalate (DBP)Dioctyl sebacate (DOS) , Dioctyl adipate, epoxy ester, chlorinated paraffin, etc.

when selecting the plasticizer variety of blown film, the following factors should be considered:

① plasticization: the formula of blown film requires good plasticizing performance and high plasticizing efficiency, otherwise it will cause the surface to blossom, stripe, bubble, even blow, pull the traction frame, etc. According to its plasticizing performance, dibutyl phthalate is the best. However, due to its volatility and water extraction, it ages very fast, especially the buried part of the agricultural film, which will harden rapidly, so it is not often used in the formula or a smaller proportion is considered. Dioctyl phthalate is a commonly used plasticizer. Because of its good performance, it is often selected by people. Petroleum ester can also be used instead of dioctyl phthalic acid vinegar, but the plasticizing performance and efficiency are poor. Therefore, if the same plasticization degree is to be achieved, the amount of petroleum Ester should be appropriately increased. Chlorinated paraffin has poor plasticizing efficiency, so the film is hard, but due to its low price and wide sources, appropriate proportion can also be considered in the formula. However, too much will make the bubble inaccurate and difficult to control due to poor plasticization, and there will be sweating during use (Precipitation)Phenomenon.

Dioctyl adipate, dioctyl sebacate and epoxy ester are also often used in blown film. Because their low temperature performance is ideal, adding appropriate proportion to the formula is of great benefit to the cold resistance of agricultural films. However, their plasticization performance is relatively poor. After adding more, the surface of the blown film will bloom and the thickness will be uneven. Moreover, their prices are also relatively expensive. Therefore, in general formulas, their total amount does not exceed ten.

② aging resistance: the aging performance of polyvinyl chloride blown film is related to plasticizer and stabilizer. The aging performance of different plasticizer varieties is also different. Generally speaking, comparing the aging resistance of agricultural films is usually comprehensively evaluated in terms of starting to stick or produce spots sooner or later, the rate of spot development, the degree of embrittlement, strength and elongation of the films. According to the results of comprehensive tests, when Petroleum Ester and dioctyl phthalate are used alone, their natural aging properties are better, and they can be dried for about two years ( Generally, when the film is folded in half, that is, it is brittle, or when the relative elongation reaches about 20%, it is considered to reach the end point of aging damage). In general, the faster the plasticizer volatilizes, the lower the elongation retention rate after aging, and the volatility and atmospheric aging resistance of dioctyl phthalate and petroleum ester are relatively close, however, the tensile strength and elongation retention rate of petroleum ester are higher than that of dioctyl phthalate, but the aging and discoloration of petroleum ester are relatively rapid in the later stage of exposure.

dibutyl phthalate has poor atmospheric aging resistance due to its high volatility, heating loss and large water extract.

due to the poor miscibility of chlorinated paraffin and polyvinyl chloride, the aging resistance is correspondingly poor, but its water extraction property in the buried part is better, therefore, an appropriate proportion can be incorporated into the formula.

at 6050 ° C constant temperature in the oven, take the soil from the paddy fields of Shanghai suburbs, bury the sample directly, and keep the soil moist.

diphenyl-octyl phosphate is better than dioctyl phthalate in aging performance. Judging from the aging speed of the buried part of the agricultural film, diphenyl phosphate-octyl phosphate does not show its advantages.

③ low temperature performance: Dioctyl adipate, dioctyl decanoic acid, epoxy ester and diphenyl phosphate monooctyl ester are cold-resistant plasticizers, which play a great role in improving low temperature performance in agricultural films, otherwise, even if the total amount of plasticizer increases, the low temperature performance will not improve much.

epoxy ester is a recommended cold-resistant plasticizer in agricultural films, especially adding epoxy ester to barium-cadmium stabilizer system has synergistic effect. After it is added, it still has obvious thermal stabilization effect, greatly improving the thermal aging performance of the product, and increasing the thermal stability and low-temperature softness of the product, which is exactly what we need. However, epoxy ester also has its disadvantages, I . e. the plasticizing performance is not ideal enough, especially under the condition of low temperature, the surface flowering phenomenon is more serious, and 5 ~ is generally added to the formula of agricultural film ~ 7 parts of epoxy ester is more suitable.