CN102260379B - Composite heat stabilizer and method for processing chlorine-containing polymer - Google Patents

Abstract

A composite heat stabilizer, which comprises 10-30% of a mixture of ethylenediaminetetraacetic acid and citric acid, 0-30% of epoxidized soybean oil, and 40-80% of an organotin heat stabilizer in terms of mass . The invention also provides a processing method of the chlorine-containing polymer. The above composite heat stabilizer has the advantages of non-toxicity, cost reduction and better stability.

Description

Composite heat stabilizer and processing method of chlorine-containing polymer

technical field

The invention relates to a thermal stabilizer and a processing method for a chlorine-containing polymer, in particular to a composite thermal stabilizer and a processing method for a chlorine-containing polymer using the composite thermal stabilizer.

Background technique

Chlorine-containing polymers are used in a wide variety of applications today. Taking polyvinyl chloride (PVC) as an example, it has been widely used in various fields of industrial and agricultural production due to its excellent corrosion resistance and good mechanical properties, as well as its advantages of low price, abundant raw materials, and mature manufacturing technology. .

When PVC is processed, it needs to be heated. However, due to defects in the structure of polyvinyl chloride, hydrogen chloride will be released when it is heated to 110°C, and hydrogen chloride will also accelerate the decomposition of polyvinyl chloride; Obvious degradation will cause discoloration of the product and reduce the mechanical properties of the product, affecting the service life of the product.

In order to solve the problem that polyvinyl chloride is easily decomposed during processing, heat stabilizers are usually added during polyvinyl chloride processing in the prior art. The main functions of heat stabilizers used in polyvinyl chloride processing are to inhibit the degradation of polyvinyl chloride molecules by replacing unstable chlorine atoms, absorbing hydrogen chloride, and reacting with unsaturated sites.

Heat stabilizers commonly used in PVC processing include lead salt stabilizers, organotin heat stabilizers and metal soap heat stabilizers. Among them, the lead salt stabilizer is the earliest heat stabilizer used in polyvinyl chloride, which has low cost and excellent thermal stability, but has toxicity, poor compatibility and dispersibility. Organotin heat stabilizers have excellent stability, but the cost is relatively high. Metal soap heat stabilizers are usually used in the form of multiple metal soap complexes, which have the advantages of being green and environmentally friendly, but their disadvantages are that they are used in large amounts and have poor stability.

In view of the above situation, it is necessary to provide a processing method of a composite heat stabilizer and a chlorine-containing polymer that can solve the above problems.

Contents of the invention

The invention proposes a composite heat stabilizer, which is non-toxic, can reduce costs and has better stability.

The invention also proposes a processing method of the chlorine-containing polymer, which can improve the stability of the processing process of the chlorine-containing polymer and reduce the cost.

A composite heat stabilizer, which comprises 10-30% of a mixture of ethylenediaminetetraacetic acid and citric acid, 0-30% of epoxidized soybean oil, and 40-80% of an organotin heat stabilizer in terms of mass .

A method for processing chlorine-containing polymers, comprising the following steps. The chlorine-containing polymer and complex heat stabilizer are first mixed in proportion to form a mixture. In terms of mass, the composite heat stabilizer comprises a mixture of ethylenediaminetetraacetic acid and citric acid, 0-30% of epoxidized soybean oil, and 40-80% of organic tin heat stabilizer. The mixture is then heated. Wherein, the usage amount of the composite heat stabilizer can account for 4-8% of the chlorine-containing polymer in terms of mass.

The above-mentioned composite heat stabilizer adopts 10-30% ethylenediaminetetraacetic acid, citric acid or a combination thereof and 0-30% epoxidized soybean oil, and is used in conjunction with an organotin heat stabilizer, so in ensuring that the composite heat stabilizer On the premise of better stability and non-toxicity, the cost can also be reduced.

Detailed ways

The processing method of the composite heat stabilizer and the chlorine-containing polymer of the present invention will be further described in detail in conjunction with the examples below.

The compound heat stabilizer of the embodiment of the present invention, by mass, it can comprise the mixture of 10～30% ethylenediaminetetraacetic acid (EDTA) and citric acid, 0～30% epoxidized soybean oil, and 40～80% % organotin heat stabilizer. In the mixture of the composite thermal stabilizer ethylenediaminetetraacetic acid or citric acid, the mass percent content of ethylenediaminetetraacetic acid can be 8-20%, and the mass percent content of citric acid can be 2-10%. The organotin heat stabilizer can be alkyltin maleate, organotin mercaptide, etc., such as (CH ₃ ) ₂ Sn(SCH ₂ COOC ₈ H ₁₇ ) ₂ . Preferably, the mass percent content of the organotin heat stabilizer in the composite heat stabilizer can be 60-80%. In addition, the epoxidized soybean oil may be commercially available soybean oil, for example, the product of Guangzhou Dongfeng Chemical Industry Co., Ltd. It should be pointed out that in other embodiments of the present invention, only one of ethylenediaminetetraacetic acid (EDTA) and citric acid can be included in the composite heat stabilizer, and at this time the mass percentage of ethylenediaminetetraacetic acid The content can be 10-30%, and the mass percent content of citric acid can be 10-30%.

Among the above-mentioned composite heat stabilizers, 10-30% of ethylenediaminetetraacetic acid, citric acid or a combination thereof, 0-30% of epoxidized soybean oil are used in conjunction with organotin heat stabilizers, so in ensuring the composite thermal stability On the premise that the agent has better stability and non-toxicity, the cost can also be reduced.

A processing method for a chlorine-containing polymer, which comprises firstly mixing the composite thermal stabilizer with the chlorine-containing polymer to form a mixture, and then heating the mixture. The heated mixture can be used for shaping or processing into products with desired shape/structure. Wherein, the chlorine-containing polymer can be one of polyvinyl chloride (PVC), chlorinated polyethylene, chlorinated polyvinyl chloride, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer or a combination thereof. In this mixture, the compound heat stabilizer can be used in an amount of 4-8% of the chlorine-containing polymer in terms of mass. Moreover, in order to facilitate the molding and processing of chlorine-containing polymers, this mixture can also be mixed with dioctyl phthalate (DOP), polyethylene wax (PE wax), calcium stearate or zinc stearate as additives . For example, in terms of mass, the amount of dioctyl phthalate is 0-65% of the chlorine-containing polymer, the amount of polyethylene wax is 0.4-1% of the chlorine-containing polymer, and the amount of calcium stearate is the amount of the chlorine-containing polymer. 0-5% of the chlorine polymer, and the amount of zinc stearate is within half of the amount of calcium stearate.

In the above-mentioned processing method of chlorine-containing polymers, since the composite heat stabilizer used has better stability and lower cost, the stability of the processing process of chlorine-containing polymers can be improved and the processing cost can be reduced. Specifically, for example, in the above-mentioned processing process, the thermal stability time of the chlorine-containing polymer can reach more than 60 minutes under the environment of 180±1°C.

In order to further illustrate that the above-mentioned composite heat stabilizer has better stability, and that the above-mentioned processing method of the chlorine-containing polymer can improve the stability of the processing process of the chlorine-containing polymer, specific examples are given below for further description.

According to the formulation shown in Table 1 (wherein the formulation is calculated in parts by mass), first weigh each component and mix to form a mixture. The mixture was then masticated for 5 minutes on a two-roll mill with a roll temperature of about 160° C. and a roll spacing of 1 mm. After the plasticization is complete, the sheet is removed to obtain a sheet sample. According to the national standard GB/T 9349-2002, it is tested by the hot oven method. First cut the obtained sheet sample into a shape of 2 cm × 2 cm and put it into a porcelain plate, then put the porcelain plate into an oven at 180±1°C to observe the discoloration of the sample. In the test results, the corresponding discoloration time of each sheet sample is shown in Table 1.

Table 1 Sample composition formula and its discoloration time

As can be seen from Table 1, the color change time of the polyvinyl chloride sheet sample formed by processing the composite heat stabilizer of the specific embodiment of the present invention at 180 ± 1° C. is more than 60 minutes, which shows that the polyvinyl chloride sheet sample Has good thermal stability. It can be seen that the composite heat stabilizer and the processing method of the chlorine-containing polymer of the present invention can improve the stability of the processing process of the chlorine-containing polymer, and can reduce costs.

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included in the scope of protection claimed by the present invention.

Claims (9)

1. A composite heat stabilizer, by mass, it comprises a mixture of 10-30% ethylenediaminetetraacetic acid and citric acid, 0-30% epoxidized soybean oil, and 40-80% organotin heat stabilizer stabilizer. 2. The composite thermal stabilizer according to claim 1, characterized in that: the content of ethylenediaminetetraacetic acid is 8-20%. 3. The composite thermal stabilizer according to claim 1, characterized in that: the content of citric acid is 2-10%. 4. The composite thermal stabilizer according to claim 1, characterized in that: the content of epoxidized soybean oil is 15-30%. 5. The composite heat stabilizer as claimed in claim 1, characterized in that: the content of organotin heat stabilizer is 60-80%. 6. A processing method for chlorine-containing polymers, comprising: Mixing the chlorine-containing polymer and the composite thermal stabilizer to form a mixture, wherein the composite thermal stabilizer comprises 10-30% of a mixture of ethylenediaminetetraacetic acid and citric acid, and 0-30% of epoxidized soybean oil in terms of mass and 40-80% organotin heat stabilizer; and heating the mixture. 7. The method for processing chlorine-containing polymers as claimed in claim 6, characterized in that: by mass, the amount of the composite heat stabilizer is 4-8% of the chlorine-containing polymer. 8. The processing method of chlorine-containing polymer as claimed in claim 6, characterized in that: plasticizer and/or lubricant should also be mixed in the mixture. 9. the processing method of chlorine-containing polymer as claimed in claim 8, is characterized in that: this plasticizer is dioctyl phthalate, and this lubricant comprises polyethylene wax, calcium stearate and stearic acid Zinc, in terms of mass, the consumption of dioctyl phthalate is 0-65% of the chlorine-containing polymer, the consumption of polyethylene wax is 0.4-1% of the chlorine-containing polymer, and the consumption of calcium stearate is 0-5% of the chlorine-containing polymer, and the amount of zinc stearate is within half of the amount of calcium stearate.