JPS6253003B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a modified copolymer obtained by radical polymerizing a monomer mixture mainly consisting of vinyl chloride and vinylidene chloride in total. The objective is to use vinyl chloride and vinylidene chloride, which have a high degree of thermal stability and are soluble in inexpensive aromatic hydrocarbon-based solvents, and which have good moldability when used as molding materials. The objective is to industrially advantageously produce a copolymer with an increased polymerization reaction rate. BACKGROUND ART Copolymers of vinyl chloride and vinylidene chloride have heretofore been studied in many ways due to their characteristic properties, ie, gas barrier properties, flexibility, or adhesive properties. However, this copolymer has poor versatility due to its remarkable decomposition properties due to heating, lack of solubility in inexpensive solvents, and poor productivity due to non-uniform polymerization reactivity, which limits its use. For example, it has been limited to soft food packaging materials or emulsion-type paints used indoors. In contrast, the present inventors have discovered that although the mixture is mainly composed of vinyl chloride and vinylidene chloride, it has a high degree of thermal stability and is soluble in a solvent mainly composed of inexpensive aromatic hydrocarbons. Surprisingly, compared to a polymer of vinyl chloride alone, its thermal stability is equal to or higher than that of a polymer of vinyl chloride alone, and is impossible with a copolymer of vinyl chloride and vinylidene chloride. The present invention was completed by discovering a method for producing a copolymer that can be dissolved in hot toluene alone or in a mixed solvent containing a small amount of esters or ketones with high productivity. That is, the present invention provides a monomer mixture consisting of vinyl chloride, vinylidene chloride, allyl chloride or methallyl chloride (hereinafter referred to as (meth)allyl chloride), and optionally other radically polymerizable monomers, The monomer mixture containing allyl chloride in an amount of 0.5 to 20% by weight in the essential monomer mixture and in which the total amount of vinyl chloride and vinylidene chloride accounts for 50% by weight or more in the total monomer mixture is subjected to radical polymerization. This is a method for producing a copolymer characterized by the following. Next, the constituent elements of the method of the present invention will be sequentially explained. The total amount of vinyl chloride and vinylidene chloride must be 50% by weight or more in the total monomer mixture, and it is preferable that each of vinyl chloride and vinylidene chloride is contained in an amount of 4 to 95% by weight. If the total amount of vinyl chloride and vinylidene chloride is not 50% by weight or more in the total monomer mixture, the properties of vinyl chloride and vinylidene chloride, such as flexibility, adhesiveness, fluidity during molding, polymerization reactivity, and thermal stability. , solubility in aromatic hydrocarbons becomes poor. If the vinyl chloride content is less than 4% by weight, the flexibility, adhesiveness, or fluidity during molding of the copolymer will be poor, and at the same time, the thermal stability and polymerization reactivity will tend to decrease. Moreover, if it exceeds 95% by weight, the flexibility, adhesiveness, or fluidity during molding of the polymer becomes poor, and at the same time, it becomes difficult to dissolve in a solvent mainly composed of aromatic hydrocarbons. If the vinylidene chloride content is less than 4% by weight, the flexibility, adhesion, and fluidity during molding of the polymer will be poor, and at the same time, the solubility in solvents mainly composed of aromatic hydrocarbons and polymerization reactivity will decrease. Easy to come. Moreover, if it exceeds 95% by weight, thermal stability or weather resistance becomes poor, solubility in solvents mainly composed of aromatic hydrocarbons or fluidity during molding becomes poor, and at the same time, polymerization reactivity tends to decrease. Next, (meth)allyl chloride must be blended in an amount of 0.5 to 20% by weight in the essential monomer mixture. If the content is less than 0.5% by weight, the thermal stability or weather resistance will be extremely poor, and at the same time, the flexibility and
This results in poor adhesion or fluidity during molding. In addition, the solubility in solvents mainly composed of aromatic hydrocarbons decreases. Moreover, if it exceeds 20% by weight, the polymerization reactivity will be significantly lowered and the mechanical strength of the obtained copolymer will be significantly lowered. Radically polymerizable monomers other than the above three types of monomers can also be used depending on the purpose. As other radically polymerizable monomers, for example, vinyl esters, vinyl ethers, acrylic esters, and vinyl ketones can be used when the purpose is to further increase solubility in solvents and fluidity during molding. In order to further enhance the imparting of , polar group-containing monomers such as acrylic acid, hydroxyethyl acrylate, maleic anhydride, N-methylacrylamide, sodium methallylsulfonate, or glycidyl methacrylate can be used. The amount of such monomer used is desirably maintained at 0 to 40% by weight based on the above-mentioned essential monomer mixture. If the amount exceeds 40% by weight, it becomes difficult for the copolymer to exhibit the above-mentioned properties targeted by the present invention. A more preferable blending ratio of the monomers used in the present invention is vinyl chloride 20 to 70% by weight, vinylidene chloride
20-70% by weight, (meth)allyl chloride 2-15
The amount of other radically polymerizable monomers is 0 to 20% by weight based on the essential monomer mixture. In the present invention, various other polymerization reaction conditions may be suitably adopted according to conventional methods, but industrially it is desirable that the polymerization temperature is 40 to 70°C and the polymerization time is 7 to 20 hours. As the polymerization method, any of suspension polymerization, emulsion polymerization, and solution polymerization can be employed. For example, when using the simplest suspension polymerization method, partially saponified PVA, methylcellulose, a copolymer of ethylene oxide and propylene oxide, or a copolymer of vinyl acetate and maleic acid can be used as the suspending agent. As the radical-generating catalyst, benzoyl peroxide, lauroyl peroxide, di2-ethylhexyl peroxydicarbonate, α,α'-dimethylvaleronitrile, etc. are used. Further, when employing an emulsion polymerization method or a solution polymerization method, the purpose of the present invention can be achieved by appropriately using a water-soluble catalyst, an oil-soluble catalyst, an emulsifier, and various general-purpose solvents. The object of the invention is achieved essentially by:
This is due to the unique physical properties of the terpolymer of vinyl chloride, vinylidene chloride, and (meth)allyl chloride, and the rate of polymerization. It is understood that the copolymer obtained under the conditions of the present invention can inhibit the so-called Zipper reaction in which dehydrochlorination reaction starts rapidly, and at the same time exhibits remarkable thermal stabilization and balances copolymerization reactivity. It is believed that a uniform polymerization reaction rate is obtained, and as a result, the crystalline portion of the copolymer disappears, so that the solubility in solvents is significantly increased or the fluidity during molding is improved. According to the present invention, a copolymer with excellent flexibility, adhesiveness, fluidity during molding, thermal stability, solubility in a container mainly composed of aromatic hydrocarbons, weather resistance, etc. can be easily obtained. It can be used as an outdoor paint, a soft to semi-rigid packaging material without the risk of coloring or decomposition under high temperatures, and a molding material for sheets, which is difficult to use with vinyl chloride and vinylidene chloride copolymers. It can also be used as a hot melt adhesive with good working efficiency even at high temperatures. Furthermore, since it is soluble in an inexpensive solvent system mainly composed of toluene, it is extremely useful as a lacquer type primer, adhesive, or paint. However, when used as a molding material, it is necessary to employ the present invention under conditions that yield a copolymer with a relatively high molecular weight. More specific applications include various coating agents for concrete, metal materials, and synthetic resins, primers before application, binders for magnetic recording media, binders for printing inks, vehicles for paint, resins for powder coating, and gas barrier packaging materials. can be given. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In addition, each characteristic of the polymer obtained in each example was measured by the following method. 1. Thermal stability: The product was maintained in a gear oven at 80° C. for 2 months without adding a heat stabilizer, and the state of discoloration was observed. 2 Solubility in toluene: 20 parts by weight of the polymer was added to 80 parts by weight of toluene, and the solubility was observed under stirring at 23°C. 3 Adhesion test; 20% by weight of the obtained polymer to mild steel plate
A tetrahydrofuran solution was prepared, and the film was coated and dried at room temperature, and the presence or absence of peeling was observed using the Erichsen test method of JIS K-6744. 4 Average degree of polymerization: The value was calculated in terms of vinyl chloride homopolymer according to the viscosity method of JIS K-6721. Example 1 In a 5 m ⁸ autoclave, 70 parts by weight of vinyl chloride, 26 parts by weight of vinylidene chloride, 4 parts by weight of methallyl chloride, OKS-7514 (partially saponified PVA with saponification degree of 40 mol%, Nippon Gosei Co., Ltd.) as a suspending agent. )) and Epan 485 (block copolymer of ethylene oxide and propylene oxide, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
1.0 parts by weight of 2-ethylhexyl peroxydicarbonate was used as a radical-generating catalyst.
Add 0.5 parts by weight and 200 parts by weight of pure water, 500 rpm
Suspension polymerization was carried out at 60°C for 13 hours under stirring.
After centrifugal dehydration and drying, a powdery polymer was obtained with a polymerization yield of 58% by weight. When this polymer was subjected to a physical property evaluation test, the results were as shown in Table 1. Examples 2 to 7 and Comparative Examples 1 to 3 In Example 1, polymerization was carried out by changing the monomer composition and keeping the other polymerization conditions the same. As a result, the test results shown in Table 1 were obtained.

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Claims (1)

[Claims] 1 A monomer mixture consisting of vinyl chloride, vinylidene chloride, allyl chloride or methallyl chloride, and optionally other radically polymerizable monomers, in which allyl chloride or methacryl chloride is contained in an amount of 0.5 to 20% in the above essential monomer mixture. % by weight, and the total amount of vinyl chloride and vinylidene chloride occupies 50% by weight or more in the total monomer mixture, and the method for producing a copolymer is characterized by radical polymerization.