JPH0432843B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin with improved physical properties, and more particularly to a method for producing a vinyl chloride resin with improved fluidity, thermal stability, transparency, softening temperature, etc. Vinyl chloride resin (hereinafter abbreviated as PVC) is a useful general-purpose resin with advanced mechanical and physical properties, but it has drawbacks such as poor moldability, especially poor fluidity of molten polymer, and poor flexibility temperature. There is. In order to improve moldability, a method of copolymerizing compounds such as vinyl acetate and alkyl vinyl ether is generally used. However, although copolymerization with such vinyl compounds lowers the viscosity of the molten polymer and improves its fluidity, it also lowers other mechanical and physical properties such as thermal stability, tensile strength, and softening temperature. The reality is that the vinyl chloride copolymers obtained can only be used for extremely limited purposes. Other methods include graft copolymerizing vinyl chloride onto a copolymer of ethylene and vinyl acetate (hereinafter abbreviated as EVA), acrylic rubber, or the like. Although the graft copolymer obtained by this method has almost no decrease in thermal stability, tensile strength, or softening temperature, it has the disadvantage of a marked decrease in transparency. As a result of intensive studies to obtain a graft copolymer with excellent thermal stability and flexibility temperature without deteriorating transparency, the present inventors found that α-methylstyrene
If vinyl chloride is graft copolymerized to a resin containing 50% by weight or more, a vinyl chloride graft copolymer resin (hereinafter referred to as graft PVC) with excellent transparency, thermal stability, flexibility temperature, etc. can be obtained. The present invention has been completed. That is, the present invention contains 50% by weight of α-methylstyrene.
Vinyl chloride in 0.5 to 30 parts by weight of the resin contained above.
This is a method for producing grafted PVC, characterized in that 50.0 to 99.5 parts by weight of vinyl chloride and 0 to 20 parts by weight of another monomer copolymerizable with vinyl chloride are graft copolymerized. For resins containing 50% by weight or more of α-methylstyrene, if the amount used is less than 0.5 parts by weight, the excellent effects of the present invention will not be fully obtained, and if more than 30% is used, the melt fluidity will deteriorate. Undesirable. The α-methylstyrene resin used in the present invention is α
- It is sufficient that the vinyl compound contains 50% by weight or more of methylstyrene, and examples of the vinyl compound used together with α-methylstyrene include ethylene, propylene,
-α-olefins with 2 to 30 carbon atoms such as butene, vinyl esters such as styrenes, vinyl acetate and vinyl propionate, and 1 to 28 carbon atoms such as methyl vinyl ether and ethyl vinyl ether
alkyl vinyl ethers, unsaturated fatty acids such as acrylic acid, methacrylic acid, fumaric acid, and maleic acid, and their esters, unsaturated nitriles such as acrylonitrile and methacrylonitrile,
Examples include vinyl chloride, vinylidene chloride, fluorine-containing ethylene, butadiene, isoprene, etc., and these may be used alone or in combination of two or more. Contains 50 vinyl compounds other than α-methylstyrene
If the amount of α-methylstyrene resin is greater than % by weight, the resulting graft copolymer resin will have poor melt fluidity and poor processability, which is not preferred. Note that the degree of polymerization of the α-methylstyrene resin is not particularly limited. Examples of the vinyl compound used with vinyl chloride include α-olefins having 2 to 30 carbon atoms such as ethylene, propylene, and 1-butene, styrenes, vinyl esters such as vinyl acetate and vinyl propionate, methyl vinyl ether, Alkyl vinyl ethers having 1 to 28 carbon atoms such as ethyl vinyl ether, unsaturated fatty acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid and their esters, unsaturated nitriles such as acrylonitrile and methacryl nitrile, Examples include vinylidene chloride, fluorine-containing ethylene, butadiene, and isoprene, and these may be used alone or in combination of two or more. It is desirable that the amount of these vinyl compounds in the grafted PVC is 20 parts by weight or less so that the physical properties do not deteriorate. In the present invention, any of emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization may be used to obtain grafted PVC. A method for obtaining grafted PVC using a general suspension polymerization method will be described. Pure water, a suspension stabilizer such as hydroxypropyl methyl cellulose, and an α-methylstyrene resin are placed in a jacketed polymerization reactor and suspended.The air inside the can is then removed, and then vinyl chloride alone or chloride is added. A monomer copolymerizable with vinyl is injected. After this, the inside of the can is heated through a jacket while stirring.
The α-methylstyrene resin is dissolved, swollen, or dispersed in a monomer such as vinyl chloride. Thereafter, a radical polymerization initiator is added to initiate graft copolymerization.
Since graft copolymerization is an exothermic reaction, the internal temperature is controlled by the jacket as necessary. After the reaction is completed, unreacted monomers such as vinyl chloride are removed from the can to obtain a slurry of grafted PVC. The slurry was dehydrated and dried in a conventional manner, and the graft
PVC is isolated. The charging method to the polymerization reactor is not limited, and among the charged raw materials such as pure water, suspension stabilizer, α-methylstyrene resin, and vinyl chloride, α
- A method may also be adopted in which the methylstyrene resin is dissolved, swollen, or dispersed in vinyl chloride and then charged together with the vinyl chloride. The grafted PVC obtained in the present invention may contain plasticizers, stabilizers, lubricants, impact-resistant agents, fillers, ultraviolet absorbers, leveling agents, surfactants,
Ingredients such as colorants and pigments are added, mixed using a known device such as a Henschel mixer or a ribbon blender, and then molded and processed by a known method such as melt extrusion, stamping, in-die extrusion, etc., and put into practical use. The grafted PVC obtained in the present invention has thermal stability,
It has excellent transparency and a high softening temperature, so it can be suitably used in the field of hard processing. The present invention will be explained below with reference to Examples. Examples 1 to 6, Comparative Example 1 In an autoclave with an internal volume of 3000, pure water 1200
After charging 60 kg of α-methylstyrene resin with the composition shown in Table 1 and 1.2 kg of hydroxypropyl methyl cellulose, and replacing the air inside with nitrogen, 540 kg of vinyl chloride was charged, and the temperature was raised to 63°C. The mixture was stirred for 3 hours to dissolve the α-methylstyrene resin. Thereafter, 3.0 kg of α·α'-azobisisobutyronitrile and 1.0 kg of 2-mercaptoethanol were charged, and the polymerization reaction was continued at 63°C for 18 hours. After removing vinyl chloride, the contents were overdried to obtain about 520 kg of white powder. Analysis of this material revealed that it contained about 12% of components other than vinyl chloride. The average degree of polymerization was about 490 in all cases. To 100 parts by weight of this grafted PVC, 2.0 parts by weight of the tin-based stabilizer "Advastab 17MJ" (trademark) and 0.5 parts by weight of stearic acid were mixed uniformly, and the mixture was further heated at 150°C for 10
A sheet was prepared by kneading with a hot roll for 1 minute and pressing at 180°C for 5 minutes. Thermal stability, flow tester flow temperature, Kratschberg softness temperature, and transparency (hereinafter collectively referred to as physical properties) were measured for samples taken from this sheet. The results are shown in Table 1. Comparative example 2 1 volume of pure water in an autoclave with an internal volume of 3,000
200Kg, hydroxypropyl methyl cellulose 1.2
Kg, α・α′-azobisisobutyronitrile 3.0Kg,
and 1.0 kg of 2-mercaptoethanol,
After replacing the internal air with nitrogen, vinyl chloride
600 kg was charged, and the polymerization reaction was continued at 63°C for 18 hours.
Thereafter, the vinyl chloride was removed and the contents were overdried to obtain 515 kg of white powder. The average degree of polymerization of this product was 490. The sheet was prepared in the same manner as in Example-1, and its physical properties were measured. The results are shown in Table 1. Comparative Example 3 Average polymerization degree of 490 obtained in Comparative Example-2
To 100 parts by weight of PVC and 14 parts of the α-methylstyrene resin used in Example 6, per 100 parts by weight of the total resin,
Tin-based stabilizer “Advustab 17MJ” (trademark) 2.0
Part by weight and 0.5 part by weight of stearic acid are mixed uniformly,
Further knead for 10 minutes with a hot roll at 150℃, then knead at 180℃.
It was pressed for 5 minutes using a hot press at ℃ to form a sheet.
The physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.

[Table] Example 7 In Example-6, vinyl chloride was replaced with vinyl chloride.
Polymerization was carried out in the same manner as in Example 6 except that 510 kg and 30 kg of propylene were used to obtain 515 kg of white powder. Hereinafter, physical properties were measured in the same manner as in Example-1. The results are shown in Table 2. Comparative Example 4 In Comparative Example-2, vinyl chloride was replaced with vinyl chloride.
Polymerization was carried out in the same manner as in Comparative Example 2, except that 560 kg and 30 kg of propylene were used, and 520 kg of white powder was obtained. 100 parts by weight of this resin and 17 parts by weight of α-methylstyrene resin (65% by weight of α-methylstyrene, 25% by weight of acrylonitrile, 7% by weight of styrene, 3% by weight of methyl methacrylate) are added to the tin-based resin per 100 parts by weight of the total resin. Stabilizer, “Advustab 17MJ”
(Trademark) and 0.5 parts by weight of stearic acid were uniformly mixed, kneaded at 150°C for 10 minutes using hot rolls, and then pressed for 5 minutes using a hot press at 180°C to form a sheet. The physical properties were measured in the same manner as in Example 1. The results are shown in Table 2.

[Table] Amounts of components other than vinyl chloride Example 8, 9 100 parts by weight of grafted PVC obtained in Examples 1 and 7 and conductive carbon “Ketsuchin Black EC” (trademark)
20 parts by weight, tin-based stabilizer “Advustab 17MJ”
(Trademark) 2.0 parts by weight and 0.5 parts by weight of stearic acid were mixed uniformly, and further kneaded with hot rolls at 140°C for 10 minutes.
A sheet was produced by pressing at 180°C for 5 minutes. Thermal stability, flow tester flow temperature, and Kratschberg softness temperature were measured for samples taken from this sheet. The results are shown in Table 3. Comparative Example 5 Example using the grafted PVC obtained in Comparative Example 2-
A sheet was produced in the same manner as in Example 8, and its physical properties were measured. The results are shown in Table 3.

[Table] The grafted PVC obtained according to the present invention has excellent thermal stability, melt flowability, and Kratschberg flexibility temperature, and can be suitably used as a material for capacitive recording media.

Claims (1)

[Claims] 1 Graft copolymerization of 50.0 to 99.5 parts by weight of vinyl chloride and 0 to 20 parts by weight of a vinyl compound copolymerizable with vinyl chloride to 0.5 to 30 parts by weight of an α-methylstyrene resin containing 50% by weight or more of α-methylstyrene. A method for producing a vinyl chloride graft copolymer resin having improved thermal stability and a high softening temperature.