JPH02167315A - Vinyl chloride resin molded article having low whitening tendency - Google Patents

Abstract

PURPOSE:To obtain the subject molded article resistant to the whitening of the surface by compounding a transparency stabilizer to a vinyl chloride polymer produced by adding a specific partially saponified PVA in the suspension polymerization of vinyl chloride monomer in the presence of a specific suspension stabilizer. CONSTITUTION:A vinyl chloride polymer is produced by adding 0.01-5wt.% (based on the produced polymer) of a partially saponified PVA having a saponification degree of 20-55mol% and an average polymerization degree of 150-600 in the suspension polymerization of vinyl chloride monomer or a vinyl monomer mixture composed mainly of vinyl chloride monomer in an aqueous medium in the presence of a suspension stabilizer consisting of a partially saponified PVA having a saponification degree of 65-80mol% and an average polymerization degree of 600-1,000. The obtained polymer is compounded with preferably 0.3-5 pts.wt. (based on 100 pts.wt. of the polymer) of a transparency stabilizer (preferably octyltin mercaptide compound, etc.) and the resultant composition is molded by conventional method to form the objective molded article.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a vinyl chloride resin molded product that is useful as sheets, bottles, tubes, etc. and has a transparent composition and is resistant to whitening.

(Conventional technology) Conventionally, vinyl chloride resin products are inexpensive, have excellent mechanical properties, chemical resistance, and weather resistance, and can be made into any hardness from hard to soft by adding many good plasticizers. It is used in a wide range of fields because it provides the following. In particular, vinyl chloride resins are used as optimal resins for molded products that require glass-like transparency, such as sheets, bottles, tubes, hoses, and heat-shrinkable films. However, since this vinyl chloride resin has poor thermal stability during molding, it has always been necessary to add a stabilizer. Many types of stabilizers are known, each based on a J° compound containing yuzu metal, but organic tin compounds and liquid kneading stabilizers are often used as they do not impair transparency.

(Problem to be solved by the invention) However, when these transparent molded products are used as packaging for products such as water, alcohol, and alcohol aqueous solutions, or as containers for these products, or when left in a hot and humid atmosphere for a long time, There is a problem in that when left for a long time, the surface becomes white and opaque, significantly reducing the value of the molded product, and an effective countermeasure has been desired.

(Means for Solving the Problems) The present invention was achieved as a result of intensive research to solve this problem, and uses vinyl chloride monomers or a mixture of vinyl monomers mainly composed of vinyl chloride. , degree of saponification as a suspending agent 65-80 mol%, average degree of polymerization 600-1000
During suspension polymerization in an aqueous medium in the presence of partially saponified polyvinyl alcohol, or in the polymer obtained thereby, a degree of saponification of 20 to 55 mol%, an average degree of polymerization of 1
Vinyl chloride with little whitening obtained by adding a transparency stabilizer to a vinyl chloride polymer obtained by adding 0.01 to 5% by weight of partially saponified polyvinyl alcohol having a molecular weight of 50 to 600% to the resulting polymer. resin sheets, bottles,
This relates to molded products such as hoses.

To explain this, the whitening prevention effect of the transparent molded article according to the present invention is achieved by a degree of saponification of 20 to 55 mol% and an average degree of polymerization of 150%.
This is achieved by adding 0.01 to 5% by weight of partially saponified polyvinyl alcohol of ~600 to the resulting polymer. This is 0. If 1% O is not moistened, whitening of the molded product cannot be prevented, and if it exceeds 5%, the whitening prevention effect will not improve as the amount increases, making it uneconomical.

There are no particular restrictions on the method of addition, such as adding it as a powder or dissolving it in a liquid, and the time of addition can be before the start of polymerization, during polymerization, in the slurry after polymerization, in the cake after dehydration, or after drying. Furthermore, it may be in the polymer immediately before molding.

In addition to vinyl chloride monomer, the polymer raw material used as the molded article material of the present invention includes a mixture of vinyl monomers mainly composed of vinyl chloride and copolymerizable with vinyl chloride (50% by weight or more of vinyl chloride). Comonomers copolymerized with vinyl chloride include vinyl esters such as vinyl acetate, vinyl propionate, vinyl caproate, and vinyl laurate; olefins such as ethylene, propylene, and isobutylene; isobutyl vinyl ether, octyl Alkyl or aryl vinyl ethers such as vinyl ether, dodecyl vinyl ether, phenyl vinyl ether; halogenated olefins such as vinylidene chloride, vinyl fluoride, allyl chloride, vinyl bromide; methyl acrylate, ethyl acrylate, n-butyl acrylate, n
-Acrylic acid or methacrylic acid esters such as butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, stearyl methacrylate; acrylic acid, methacrylic acid, crotonic acid, acrylonitrile, styrene, maleic anhydride, itaconic anhydride and other monomers copolymerizable with vinyl chloride.

The molded article according to the invention has f! in an aqueous medium using these monomers. I? In lia polymerization, it is necessary to carry out the polymerization in the presence of partially saponified polyvinyl alcohol with a degree of saponification of 65 to 80 mol% and a degree of polymerization of 600 to 1,000 as a suspending agent. Other suspending agents commonly used during polymerization 1. Water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose; acrylic acid polymers; water-soluble polymers such as gelatin; sorbitan monolayers; Oil-soluble emulsifiers such as sorbitan triolate, glycerol tristearate, ethylene oxide propylene oxide block copolymer; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerol oleate, sodium laurate, etc. There is no problem even if two or more types are used in combination.

The polymerization initiator used in this polymerization may also be one that has been conventionally used in vinyl chloride polymerization, such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and jetoxyethyl peroxydicarbonate. Percarbonate compounds such as carbonate; Perester compounds such as t-butyl peroxyneodecanate, t-butyl peroxypivalate, t-hexyl peroxypivalate, α-cumyl peroxyneodecanate; Decanoyl peroxy Peroxides such as oxide, lauroyl peroxide, benzoyl peroxide, acetylcyclohexylsulfonyl peroxide, 2,4.4-trimethylpentyl-2-peroxyphenoxyacetate, 3,5.5-trimethylhexanoyl peroxide ;α.

Azo compounds such as α'-azobisisobutyronitrile, α,α'-azobis-2,4-dimethylvaleronitrile, α,α'-azobis(4-methoxy-2,4-dimethylvaleronitrile); These can be used alone or in combination of two or more. Also,
Potassium persulfate, ammonium persulfate, hydrogen peroxide, etc. can also be used in combination with these catalysts.

Further, if necessary, polymerization regulators, chain transfer agents, pH regulators, gelling improvers, antistatic agents, scale inhibitors, etc., which are appropriately used in vinyl chloride polymerization, may be added.

Other conditions for this polymerization 1. The aqueous medium, vinyl chloride monomer, in some cases other comonomers, suspending agents, polymerization initiators, etc. may be charged in the same manner as conventional methods. The polymerization conditions such as the charging ratio and polymerization temperature may also be the same.

The vinyl chloride resin thus obtained is
By blending 0.3 to 5 parts by weight of a transparency stabilizer per 0 parts by weight, vinyl chloride resin molded articles with little whitening can be obtained. If the amount added is less than 0.3 parts by weight, the effect of thermal stability cannot be obtained, and if it exceeds 5 parts by weight, no further improvement in the effect can be expected and the cost will increase economically, which is not preferable.

Examples of the transparency stabilizer include mercaptide-based organotin compounds such as dibutyltin mercaptide-based compounds and octyltin mercaptide-based compounds; maleate-based organotin compounds such as dibutyltin maleate-based compounds and octyltin maleate-based compounds; and dibutyltin laurate-based compounds. Examples include laurate-based organotin compounds such as compounds; Ca-Ba-based, Ba-Zn-based, or Ca-Zn-based liquid composite stabilizers; and these are used alone or in combination of two or more.

However, when the obtained molded product is used for food, octyltin mercaptide compounds,
Octyltin maleate compound.

Alternatively, it is desirable to select a Ca--Zn based liquid composite stabilizer, and when seeking both transparency and anti-whitening effects, a mercaptide based organotin compound is preferably used.

Furthermore, when using this for blow bottles or heat-shrinkable films and sheets, the butadiene-styrene copolymer resin is added at a ratio of 4 to 15 parts by weight per 100 parts by weight of the vinyl chloride resin. is preferred. Examples of the butadiene-styrene copolymer resin include methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, and methyl methacrylate-acrylonitrile-butadiene copolymer.
Examples include styrene copolymers.

The above vinyl chloride resin may be used as required.

Plasticizers such as P, stabilizing agents such as epoxidized soybean oil,
Processing aids such as methyl methacrylate resin (MMA), UV absorbers, colorants such as bluing agents, lubricants,
Other additives such as fJ2 may be added within a range that does not impair transparency.

Each of the above extraction components is generally blended with a lithium hibinyl resin by the method (2), extrusion molding, and calender molding.

Transparent molded products with less whitening can be made by injection molding, Plow J & molding, etc.

The obtained molded product was made into a sheet with a size of 0.
The transparency (haze) value of the wet water test whitening 1"if at a temperature of 160°C or higher, which is ap+added, was generally 5.0 or less, and the best (directly, 3.0 degrees or more).

The molded product according to the present invention is a film for packaging or good quality products,
Shrinkage film, films and sheets such as sheets for construction work or home use, for drinking water, alcohol, industrial use, or medicine, bottles for various uses, agricultural use, or Suitable for industrial hoses, tubes, etc.

(Examples) Hereinafter, the JL and interbody aspects of the present invention will be explained using Examples and Comparative Examples, but the present invention is not limited thereto.

(Manufacture of vinyl chloride resin) Example ↓.

900 kg of deionized water was placed in a stainless steel autoclave with a 2000 Q volume stirrer and jacket.
, =lZ 300 g of partially saponified polyvinyl alcohol with a degree of homopolymerization of 770 and a degree of saponification of 72.4 mol%, 60 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 300 and a degree of saponification of 48.2 mol%, azobis-2,4-dimethyl Pour 180g of valeronitrile into each container, and add 50g of valeronitrile to each container.
After degassing until the volume became 11 g, 600 kg of vinyl chloride monomer was charged. The reaction force inside the polymerization vessel was 8.0 kg/JG.
Unreacted monomers were collected when the temperature decreased to . The slurry containing the polymer was taken out of the vessel and dehydrated and dried to obtain a vinyl chloride resin according to the present invention.

Example 2 In the previous example, instead of adding 60 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 300 and a degree of saponification of 48.2 mol% before the start of polymerization, 120 g of this was added to the slurry after the completion of polymerization. A vinyl chloride resin was obtained in the same manner as in the previous example except for dehydration and drying.

Example 3゜In Example 1, the Hei 1 Kuton degree was 300 and the saponification degree was 48.
Instead of 2 mol% partially saponified polyvinyl alcohol,
A divinyl vinyl resin was obtained in the same manner as in Example Y, except that partially saponified polyvinyl alcohol having an average degree of polymerization of 500 and a degree of saponification of 36.8 mol% was used.

Example 4゜Average degree of polymerization in actual stripping: 770, saponification degree: 72.4
300 g of partially saponified polyvinyl alcohol in mole%
In place of , flat/J degree of polymerization is 790. 360 g of partially saponified polyvinyl alcohol with 73.0 mol% saponified skin;
29% methoxy substituents, 1 hydroxypropoxy substituent
A vinyl chloride resin was obtained in the same manner as in Example 1, except that 3 g of 0% hydroxypropyl methyl cellulose was used.

Comparative Example 1゜Ilt homopolymerization degree in Example 1: 770, saponification degree: 72
．． 300 of 4 mol% partially saponified polyvinyl alcohol
g, XI, L Instead of using 60 g of partially saponified polyvinyl alcohol with a degree of homopolymerization of 300 and a degree of saponification of 48.2 mol%,
．． 270 of 0 mol% partially saponified polyvinyl alcohol
A vinyl chloride resin was obtained in the same manner as in Example (except that G was used).

Comparative Example 2゜ Average degree of polymerization in Example 770, degree of saponification 72.4
Instead of using 300 g of partially saponified polyvinyl alcohol with mol % and 60 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 300 and a saponification degree of 48.2 mol %, methoxy substituents 20% and hydroxypropoxy substituents 8%
A vinyl chloride resin was obtained in the same manner as in Example 1, except that 300 g of hydroxypropyl methylcellulose was used.

Example 5 Deionized water was added to a stainless steel autoclave with an internal volume of 2000 Q and a stainless steel autoclave equipped with a stirrer F1] and a jacket.
kg, 300 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 980 and a degree of saponification of 78.0 mol%, 60 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 300 and a degree of saponification of 48.2 mol%, di(2-ethylhexyl) peroxy After charging 250g of dicarbonate and deaerating the inside of the container until the volume became 50ml and 11g, 600kg of vinyl chloride monomer was charged. While stirring the inside of the vessel, hot water was passed through the jacket to raise the temperature to 57.0°C, and polymerization was continued while maintaining that temperature. The pressure inside the polymerization vessel is 6.0 kg.
When the concentration decreased to /ff1G, unreacted monomers were collected. The slurry containing the polymer was taken out and dehydrated and dried to obtain a 1lfi vinyl resin according to the present invention.

Example 6゜In Example 5. Average degree of polymerization: 300, saponification degree: 48.
A vinyl chloride resin was prepared in the same manner as in Example 5, except that instead of adding 60 g of 2 mol % partially saponified polyvinyl alcohol before the start of polymerization, 120 g of this was added to the slurry after polymerization and dehydrated and dried. I got it.

Example 7゜In Example 5, the average degree of polymerization was 980 and the degree of saponification was 78.
300 g of 0 mol% partially saponified polyvinyl alcohol
Instead of the average degree of polymerization of 980. Saponification degree 78.0 mol%
360 g of partially saponified polyvinyl alcohol and
Hexy substituents 29%, hydroxypropoxy substituents lO
A vinyl chloride resin was obtained in the same manner as in Example 1, except that 3 g of hydroxypropyl methylcellulose (3 g) was used.

Comparative Example 3゜Average degree of polymerization in Example 5: 980, saponification degree: 78.0
Instead of using 300 g of partially saponified polyvinyl alcohol with an average degree of polymerization of 300 and a degree of saponification of 48.2 mol %, a portion with an average degree of polymerization of 2640 and a degree of saponification of 81.0 mol % was used. Besides using 270g of saponified polyvinyl alcohol,
A vinyl chloride resin was obtained in the same manner as in Example 5.

(Whitening test for molded products) The vinyl chloride resins obtained in Examples 1 to 4 and Comparative Examples 1 to 2 above are shown below (sheets).
The components of and (bottle) were mixed and kneaded using a test roll at 170°C for 3 minutes to prepare a sheet with a thickness of 0°5m, which was further pressed at 180°C for 6 minutes to form a transparent test piece.

Further, for each of the vinyl chloride resins obtained in Examples 5 to 7 and Comparative Example 3, the following (hose) components were blended, and a transparent resin with a thickness of 0 and 5 ++ was prepared in the same manner as described above. A press sheet was created.

(Sheet) Vinyl chloride resin 100 parts by weight D O
P5. Q n dibutyltin mercaptide 3,511 acrylic auxiliary agent 1. Qn stearyl alcohol
0.5II butyl stearate
0.5//(bottle) Vinyl chloride resin 100 parts by weight M B
S7. Q n Acrylic auxiliary agent 2. OII octyltin mercapto stabilizer 1.81I stearic acid monoglyceride l, Qn polyethylene wax
0.2〃(Hose) Vinyl chloride resin 100 parts by weight DOP
70/1 Epoxidized soybean oil 2.00 Liquid Ba-Zn stabilizer 1.5tt Soak these in warm water kept at 80°C for 30 minutes, then remove from the water, and after 24 hours, use a digital turbidity meter ND11- 200 (manufactured by Hondenshoku Kogyo Co., Ltd.), the haze and total transmittance were measured according to JIS K-7105, and the results are shown in the following table.

(Effects of the Invention) Molded products such as sheets, bottles, hoses, tubes, etc. obtained by the present invention can be sterilized by contact with water, alcohol, or an aqueous alcohol solution, or in a high-temperature and humid atmosphere, such as during a steam sterilization process in food containers. It is possible to prevent whitening of the surface due to the length 11 and the gap left unattended.

Claims (1)

[Claims] 1. Vinyl chloride monomer or a mixture of vinyl monomers mainly composed of vinyl chloride is used as a suspending agent with a saponification degree of 6.
During suspension polymerization in an aqueous medium in the presence of partially saponified polyvinyl alcohol with an average degree of polymerization of 5 to 80 mol% and an average degree of polymerization of 600 to 1000, or in the resulting polymer, a saponification degree of 20 to 55 mol% is added. , average degree of polymerization 150-6
Vinyl chloride resin molding with less whitening obtained by adding a transparency stabilizer to a vinyl chloride polymer obtained by adding 0.01 to 5% by weight of partially saponified polyvinyl alcohol No. 00 to the resulting polymer. Goods.