JPS64990B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinylidene chloride resin composition with excellent thermal stability and a method for producing the same. Vinylidene chloride resin usually consists of a vinylidene chloride copolymer and appropriate amounts of additives such as plasticizers and stabilizers, and has excellent oxygen gas barrier properties, moisture resistance, transparency, flexibility, oil resistance, and heat resistance. It has characteristics such as contractility. For this reason, it has become indispensable as a packaging material for various foods, and its uses have been expanding more and more in recent years. However, a drawback is poor thermal stability during melt processing. Generally, in order to improve the thermal stability of vinylidene chloride-based resins during melt processing, an antioxidant is used in combination with a thermal stabilizer such as epoxidized vegetable oil. In recent years, vitamin E has come to be used as an antioxidant for vinylidene chloride resins, but in order to exert its stabilizing effect, it must be heated to 160°C in order to form chromophores called tocoquinone and tocoredo. In the processing of vinylidene chloride-based resins that exceed this level, although they have been shown to be effective, they have not been sufficient. The present inventor has focused on preventing coloration when using vitamin E as a stabilizer for vinylidene chloride resin, and has conducted extensive research with the aim of obtaining an additive (synergist) and an addition method that increase the stabilizing effect of vitamin E. As a result, we found that ethylenediaminetetraacetic acid (hereinafter referred to as "vitamin E synergist")
We found that EDTA (abbreviated as EDTA) and its salts are effective. It has also been found that the effect is further enhanced when an alkyl thiodipropionic acid ester having an alkyl group having 12 to 18 carbon atoms is added together with a synergist selected from vitamin E, EDTA, and their salts. and,
Vitamin E has the greatest effect,
When a synergist selected from EDTA and its salts is added in combination with a thiodipropionic acid alkyl ester, the vitamin E
The inventors discovered that a special method of adding a portion of the monomer into the monomer led to the completion of the present invention. That is, the present invention provides, in addition to ordinary plasticizers, stabilizers, etc., 0.0005 to 0.2 parts of vitamin E and a synergist selected from EDTA and its salts per 100 parts by weight of vinylidene chloride copolymer (the same applies hereinafter).
0.0005 to 0.2 parts are to be blended together.
Furthermore, when 0.0005 to 0.2 parts of a thiodipropionic acid alkyl ester having an alkyl group having 12 to 18 carbon atoms is blended together, the thermal stabilization effect is further improved. In these cases, the maximum effect is achieved by adding 0.0005 to 0.0005 of the added vitamin E.
The special method of addition is that 0.01 part is added to the monomer and the remainder is added to the resulting copolymer. The vinylidene chloride copolymer referred to in the present invention refers to a copolymer containing vinylidene chloride as a main component and an unsaturated monomer having copolymerizability, and is 60 to 95% (wt%) in the copolymer. , hereinafter the same) contains vinylidene chloride. These are usually obtained by copolymerizing 50 to 98% vinylidene chloride and 50 to 2% of a copolymerizable unsaturated monomer by a conventional method. Examples of copolymerizable unsaturated monomers include vinyl chloride, acrylic esters such as methyl acrylate and butyl acrylate, methacrylic esters such as methyl methacrylate and butyl methacrylate, acrylonitrile, isobutylene, vinyl acetate, etc. Two or more types of these copolymerizable unsaturated monomers can also be used in combination. The vitamin E used in the present invention includes various tocopherols α, β, γ, and δ, and mixtures of tocopherols selected from these, and these may be natural products or synthetic products. . In addition, the EDTA salts used in the present invention include, for example, compounds of EDTA and alkali and alkaline earth metals, such as sodium EDTA, calcium EDTA, magnesium EDTA, etc.
Examples include EDTA zinc. Further, examples of the thiodipropionic acid alkyl ester used in the present invention include dilaurylthiodipropionate and distearylthiodipropionate. The amount of stabilizer added in the present invention is 0.0005 to 0.2 part, preferably 0.001 to 0.05 part, per 100 parts of vinylidene chloride copolymer, and less than 0.0005 part is sufficient to achieve the purpose of the present invention. Moreover, if it exceeds 0.2 parts, it is not only economically disadvantageous, but also causes problems such as the color tone and transparency of the molded product being impaired, which is not preferable. In particular, if the amount of vitamin E added to the monomer exceeds the addition range specified in the present invention, not only will the polymerization rate be delayed, but the resulting vinylidene chloride copolymer will be colored.
The thermal stability of the molded product also deteriorates. In addition, EDTA or its salt, or thiodipropionic acid alkyl ester used in combination with vitamin E may be added to the monomer or to the vinylidene chloride copolymer, and these methods of addition may be There is no difference in the thermal stabilization effect of vinylidene chloride resins. In addition, when processing vinylidene chloride resins, in addition to the above-mentioned stabilizers, plasticizers such as acetyl tributyl citrate, dioctyl adipate, or dibutyl sebacate should be added in an amount of 10% or less, and epoxidized soybean oil or Up to 5% of epoxidized vegetable oil, such as epoxidized linseed oil, is used, and the method of addition thereof may be either monomer or vinylidene chloride copolymer. Hereinafter, the features and effects of the present invention will be explained using Examples. In addition, in Examples and Comparative Examples, parts or % refer to parts by weight and % by weight, respectively.
It represents. Example 1 Glass lined 30 with sliding stirrer
A reactor is charged with 15 kg of deionized water in which 20 g of hydroxypropyl methylcellulose is dissolved, and after the system is purged with nitrogen, 8 kg of vinylidene chloride monomer in which 15 g of diisopropyl peroxydicarbonate is dissolved and 2 kg of vinyl chloride monomer are added thereto. Polymerization was started by increasing the internal temperature to 42℃ while stirring, and the temperature was increased to 15℃.
After an hour, the temperature was raised to 53°C and polymerization was continued for an additional 19 hours. Thereafter, unreacted monomers are released, and the slurry is taken out and dehydrated. Obtained vinylidene chloride
After drying the vinyl chloride copolymer for 40 hours in a hot air dryer at 40°C, 5 parts of acetyl tributyl citrate, 1.5 parts of epoxidized linseed oil, 0.01 part of d-α tocopherol, and EDTA were added to 100 parts of the copolymer. Add 0.02 part of disodium. The obtained vinylidene chloride-vinyl chloride copolymer resin composition is aged at 40°C for 40 hours. Evaluation of thermal stability The obtained vinylidene chloride copolymer resin composition was heated to 170
℃, melted resin while kneading at 50 revolutions/min.
After sampling every minute, the discoloration over time was observed every 5 minutes to evaluate the thermal stabilization effect during processing of vinylidene chloride resin. 〓 ◎ 〇 △ × Best Excellent Good Acceptable Example 2 Suspending agent, deionized water, monomer, etc. were prepared in the same manner as in Example 1, except that 0.3 g of d-α tocopherol was added to the vinylidene chloride monomer, Polymerization is initiated by raising the internal temperature to 42°C while stirring, and after 15 hours, the temperature is raised to 53°C, and polymerization is continued for an additional 20 hours, followed by the same treatment. For 100 parts of the obtained vinylidene chloride-vinyl chloride copolymer, 5 parts of acetyl tributyl citric acid, 1.5 parts of epoxidized linseed oil,
Disodium EDTA (0.02 part) and dl-α tocopherol are each added in a total amount of 0.01 part. After aging the copolymer resin composition at 40° C. for 40 hours, the thermal stabilization effect was evaluated using plastograph in the same manner as in Example 1. Example 3 To 100 parts of vinylidene chloride-vinyl chloride copolymer obtained in Example 2, 5 parts of acetyl tributyl citric acid, 1.5 parts of epoxidized linseed oil,
0.01 part of disodium EDTA, 0.01 part of dilauryl thiodipropionate (hereinafter abbreviated as DLTDP), and dl-α tocopherol are added so that the total amount added is 0.01 part. Then, after aging the copolymer resin composition at 40°C for 40 hours, Example 1
The thermal stabilization effect was evaluated using Plastograph in the same manner as above. Comparative Examples 1 to 3 To 100 parts of the vinylidene chloride-vinyl chloride copolymer obtained in Example 1, 5 parts of acetyl tributyl citrate was added so that the addition ratio of various additives was as shown in Table 1. , along with 1.5 parts of epoxidized linseed oil, and the copolymer resin composition is aged at 40° C. for 40 hours. Then, the thermal stabilization effect of the resin composition was evaluated using plastograph in the same manner as in Example 1. The evaluation results of Examples 1 to 3 are shown in Table 1 together with the results of Comparative Examples 1 to 3.

[Table] Pre-addition in Table 1 means the method of adding the additive to the mixed monomer before polymerization, and post-addition means the method of adding the additive to the obtained vinylidene chloride copolymer after polymerization. means the method (the same applies hereinafter). As is clear from Table 1, along with vitamin E
EDTA disodium is superior to vitamin E alone,
It can be seen that disodium EDTA is an excellent synergist of vitamin E. Furthermore, it can be seen that the heat stabilizing effect is increased by the method of adding a portion of vitamin E to the monomer according to the present invention, and by using it in combination with DLTDP. Examples 4 to 9 Using the vinylidene chloride-vinyl chloride copolymer obtained in Example 2, 5 parts of sebacic acid dipyl ester, 1.5 parts of epoxidized soybean oil, and d-α tocopherol were added to 100 parts of the copolymer. The total addition ratio is
After adding 0.01 part of each EDTA salt and 0.01 part of each of the various EDTA salts shown in Table 2,
Time aging. Then, as in Example 1, the thermal stabilization effect was evaluated using plastograph. Comparative Example 4 Using the vinylidene chloride-vinyl chloride copolymer obtained in Example 2, 5 parts of dibutyl sebacate, 1.5 parts of epoxidized soybean oil, and d-α tocopherol were added to 100 parts of the copolymer. Add so that the total addition ratio is 0.02 part, and age at 40°C for 40 hours. Then, as in Example 1, the thermal stabilization effect was evaluated using plastograph.

[Table] Table 2 shows the thermal stabilization effects of Examples 4 to 9 and Comparative Example 4, and it is clear that vinylidene chloride-vinyl chloride to which EDTA or its salts were added together with vitamin E It can be seen that the polymer resin composition has better thermal stability than the composition without the addition. Examples 10-13 In a monomer mixture of 80% vinylidene chloride and 20% vinyl chloride, 0.15 parts of diisopropyl peroxydicarbonate and 100 parts of the resulting vinylidene chloride-vinyl chloride copolymer were added to 100 parts of the mixed monomer.
0.004 parts of each of the various vitamins shown in Table 3 were added to the total amount of vitamin E shown in Table 3, and polymerization was carried out using hydroxypropyl methylcellulose as a suspending agent at 42°C for 15 hours and then at 53°C for 20 hours in a conventional manner. , processed and dried in the same manner as in Example 1. To 100 parts of the obtained vinylidene chloride-vinyl chloride copolymer, 5 parts diptyle sebacate, 1.5 parts epoxidized soybean oil, and disodium EDTA were added so that the total amount of vitamin E added was 0.01 part each.
0.01 part to prepare several copolymer resin compositions. After aging at 40°C for 40 hours, the thermal stabilization effect was evaluated using the same method as in Example 1. Table 3 shows the type of vitamin E used and the evaluation results.

[Table] As is clear from Table 3, the copolymer resin composition according to the present invention has no difference in thermal stability during processing even if the type of vitamin E is different, and is excellent in all cases. I understand that very well. Examples 14 to 19 In a monomer mixture of 80% vinylidene chloride and 20% vinyl chloride, 0.15 parts of diisopropyl peroxydicarbonate is added to 100 parts of the mixed monomer, and d is added to 100 parts of the resulting vinylidene chloride-vinyl chloride copolymer. -α tocopherol, disodium EDTA, and thiodipropionic acid alkyl ester were added so that the types and amounts thereof were as shown in Table 4, and hydroxypropyl methylcellulose was used as a suspending agent at 42°C for 15 hours. Polymerization is carried out in a conventional manner at 53° C. until the polymerization rate reaches about 90%, and the same treatment as in Example 1 is carried out to obtain a vinylidene chloride-vinyl chloride copolymer. For 100 parts of the obtained copolymer, 3 parts of acetyl tributyl citrate, 3 parts of dibutyl sebacate, 1.5 parts of epoxidized linseed oil, and the types of d-α tocopherol, disodium EDTA, and alkyl thiodipropionate. and added so that the amounts added were in the ratios shown in Table 4 to obtain a resin composition. After aging this at 40° C. for 40 hours, the thermal stabilization effect was evaluated using plastograph as in Example 1. The results are shown in Table 4 along with comparative examples. As is clear from Table 4, the addition of vitamin E alone has no effect, regardless of whether it is added as a pre-addition, as a post-addition, or as a combination of both;
It only becomes effective when added in combination with salts. Furthermore, it is most preferable to add a thiodipropionic acid alkyl ester in combination to maximize the thermal stabilization effect of the present invention. Even when used in combination with EDTA salt, if the pre-added amount of vitamin E exceeds the range specified in the present invention, the resulting vinylidene chloride copolymer will be colored and the thermal stability of the molded product will deteriorate. In addition, EDTA, which is formulated in combination with vitamin E.
It can be seen that there is no difference in the effect of salts and thiodipropionic acid alkyl esters whether they are added to the monomer or to the resulting copolymer, and they are effective in either case. As mentioned above, in the production of vinylidene chloride-based resins, there is a method in which a small amount of vitamin E is first added to a monomer, and the remaining amount is added to the resulting copolymer, and an EDTA salt is used as a vitamin E synergist. It was discovered that thiodipropionic acid alkyl ester has an excellent thermal stabilizing effect, and that this effect is further improved by combining it with a thiodipropionic acid alkyl ester.We have developed a vinylidene chloride resin composition with excellent thermal stability. I started getting things.

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Claims (1)

[Claims] 1. 0.0005 to 0.2 parts by weight of vitamin E, 0.0005 to 0.2 parts by weight of one or more ethylenediaminetetraacetic acids selected from ethylenediaminetetraacetic acid and its salts, per 100 parts by weight of vinylidene chloride copolymer. A vinylidene chloride resin composition comprising: 2 Per 100 parts by weight of vinylidene chloride copolymer, 0.0005 to 0.2 parts by weight of vitamin E, 0.0005 to 0.2 parts by weight of one or more ethylenediaminetetraacetic acids selected from ethylenediaminetetraacetic acid and its salts, alkyl thiodipropionic acid ester A vinylidene chloride resin composition containing 0.0005 to 0.2 parts by weight. 3 Per 100 parts by weight of vinylidene chloride copolymer, 0.0005 to 0.2 parts by weight of vitamin E, 0.0005 to 0.2 parts by weight of one or more ethylenediaminetetraacetic acids selected from ethylenediaminetetraacetic acid and its salts, and thiodipropion as necessary. Acid alkyl ester 0.0005
In the production of a vinylidene chloride-based resin composition containing ~0.2 parts by weight of vitamin E0.0005~
A method for producing a vinylidene chloride resin composition, which comprises adding 0.01 part by weight to a monomer in advance.