JPH072881B2 - Vinyl chloride polymer composition with high volume resistivity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride polymer composition having a high volume resistivity.

Vinyl chloride polymer (hereinafter abbreviated as PVC) is originally a plastic with a high volume resistivity and is commonly used as an electrical insulating material. However, a small amount of metal compound mixed in the manufacturing process causes a decrease in volume resistivity. Occurs. For example, sodium ion Na ⁺ can be given as a common causative metal. Since caustic soda is generally used in the vinyl chloride purification step, it is extremely difficult to avoid the inclusion of a trace amount of sodium ion Na ^{+ in} vinyl chloride. In addition, it is virtually impossible to completely prevent mixing of other metal ions. It is also known to add clay to increase the volume resistivity, but this is a PVC that has other properties and has satisfactory performance.
No composition is obtained. As a method of obtaining a PVC composition having a large volume resistivity, there is a method of adding a copolymer of styrene and maleic anhydride or a polymer of vinyl ether and maleic anhydride (JP-A-57-119944 and JP-A-56- 15
No. 9242), there is a problem in obtaining a PVC composition having uniform properties due to variations in the obtained effects.

The present inventors have made extensive studies on a PVC composition having a large volume resistivity, and when adding a specific amount of polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone to PVC, the volume resistivity is greatly improved and the variation is extremely large. It was found that the number was small, and further research was conducted to finally reach the present invention.

Polyvinylpyrrolidone having an average molecular weight of 10,000 to 360,000 and water-soluble polymers other than polyvinylpyrrolidone were used for the polymerization in the process of producing the vinyl chloride-based polymer after the polymerization was initiated and the polymerization rate of vinyl chloride exceeded 20%. 50 to 5,000 ppm and 10 to 5,000, respectively for vinyl chloride
A vinyl chloride-based polymer composition having a large volume resistivity, which is characterized by being added at 0 ppm.

Why is PV obtained when a certain amount of polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone are present?
It is not clear whether the volume resistivity of the C composition is improved or not, but it is presumed that polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone are for shielding metal ions in PVC.

The polyvinylpyrrolidone used in the present invention has an average molecular weight of 10,0 in terms of dispersibility and effect in a PVC composition.
It is from 00 to 360,000.

Since polyvinylpyrrolidone and water-soluble polymers other than polyvinylpyrrolidone may be contained in the PVC composition, it is desirable to add them to PVC during molding, but to uniformly disperse them, add them during the polymerization of PVC. It is also possible to keep it. In the suspension polymerization of PVC, polyvinylpyrrolidone is used as a dispersant, but in order to use polyvinylpyrrolidone for the purpose of the present invention, it is necessary to add a predetermined amount again after the polymerization system is uniformly dispersed. is there. By doing so, polyvinylpyrrolidone is incorporated into the PVC polymer during polymerization. In this polymerization, polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone are added after about 20% of vinyl chloride has been polymerized and particle formation is completed.

The addition amounts of polyvinylpyrrolidone and water-soluble polymers other than polyvinylpyrrolidone are 50 to 5,000 ppm and 10 to 5,000 ppm, respectively, with respect to the vinyl chloride used for the polymerization.

As the PVC used in the present invention, not only vinyl chloride homopolymers but also copolymers with other copolymerizable vinyl compounds can be used. Of course, Kraft polymers for other polymers can also be used.

Examples of vinyl compounds copolymerizable with vinyl chloride include olefins such as ethylene and propylene, vinyl acetates such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether,
Examples thereof include acrylic acid, methacrylic acid and esters thereof, maleic acid, fumaric acid and esters thereof, acrylonitrile, vinylidene chloride, and fluorine-containing ethylene.

Further, as the other polymer used in the grout polymerization, any polymer capable of craft polymerization such as polyolefin such as polyethylene and polypropylene, ethylene-vinyl acetate copolymer, polyacrylate, butadiene-containing copolymer may be used. Among them, those having rubber elasticity are preferable.

Further, as the PVC used in the present invention, suspension polymerization, emulsion polymerization, solution polymerization, PVC polymerized by a known method such as bulk polymerization.
Any of them can be used. A PVC obtained by adding polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone to the polymerization system is preferable because a polyvinylpyrrolidone and a PVC composition in which a water-soluble polymer other than polyvinylpyrrolidone are uniformly mixed can be obtained.

Among the methods for directly obtaining the PVC composition of the present invention as a polymer, a method by a suspension polymerization method will be shown.

Any polymerization catalyst can be used as long as it is used for suspension polymerization of vinyl chloride. For example, lauroyl peroxide, t
-Butyl peroxypivalate, organic peroxides such as diisopropyl peroxydicarbonate, α
Diazo compounds such as α'-azobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile, which are used alone or as a mixture of two or more kinds.

As the dispersant, any dispersant can be used as long as it is used for suspension polymerization. Examples thereof include partially saponified polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, gelatin and the like. These may be used alone or in combination of two or more.

The above dispersant and polymerization catalyst are charged, together with other resins as necessary, in a polymerization machine containing a predetermined amount of water, the air inside the polymerization machine is removed by decompression or nitrogen purging while sufficiently dispersing with stirring, and then vinyl chloride is required. If available, it is charged with a copolymerizable vinyl compound and stirred at reaction temperature (usually 30
Up to 70 ° C) to polymerize vinyl chloride. At that time, polyvinylpyrrolidone and a polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone are taken into the PVC obtained by coexisting a water-soluble polymer other than polyvinylpyrrolidone, but as described above, other than polyvinylpyrrolidone and polyvinylpyrrolidone. The water-soluble polymer is added after the vinyl chloride is polymerized to about 20% and the particle formation is completed. A PVC containing polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone is obtained in the same manner as in ordinary suspension polymerization of vinyl chloride except that polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone are added.

The PVC composition of the present invention can be obtained by adding polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone to PVC, or by polymerization in the presence of polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone as described above. However, in actual use, a plasticizer, a stabilizer, a filler, an ultraviolet absorber, a colorant, a pigment, a lubricant, etc. are added and used.

Examples of plasticizers that can be used include phthalic acid esters, adipic acid esters, phosphoric acid esters, polyester plasticizers, trimellitic acid esters, epoxy plasticizers, and chlorinated paraffins.

As the stabilizer, tribasic lead sulfate, lead stabilizers such as lead stearate, metal soap stabilizers such as calcium stearate and zinc stearate, octyl tin mercaptide,
Examples include organic tin stabilizers such as dibutyltin malate,
Further examples include auxiliary stabilizers such as epoxy stabilizers, organic phosphites, aminocrotonates, 2-phenylindole, pentaerythritol, solevitol and phosphite chelators.

It is possible to use a conventionally known substance as a filler, a flame retardant, etc. that can be added, and, for example, antimony trioxide, ammonium bromide, guanidine nitrogen compounds, borax, ammonium sulfate, calcium carbonate, Kaolin clay,
Examples include gypsum, titanium oxide, magnesium hydroxide, calcium silicate and the like.

Examples of the ultraviolet absorber include benzophenone-based compounds such as 2,4-dihydroxybenzophenone and 2- (2'-hydroxy-).
Examples thereof include benzotriazole-based UV absorbers such as 5-methylphenyl) benzotriazole and salicylate ester-based UV absorbers such as phenyl salicylate.

Examples of the lubricant include hydrocarbon-based lubricants such as natural paraffin, liquid paraffin and polyethylene wax, fatty acid-based lubricants such as stearic acid, fatty acid amide-based lubricants such as stearic acid amide, ester-based lubricants such as ethylene glycol monostearate, and stearyl alcohol. And higher alcohol-based lubricants, metal soap-based lubricants such as calcium laurate, and esters of higher fatty acids with higher alcohols.

As the antioxidant, 2,2'-methylene-bis- (4-
Examples thereof include bisphenol-based antioxidants such as methyl-6-tert-butylphenol), monophenol-based antioxidants such as 2,6-ditertiary-butylphenol, and hydroquinone-based antioxidants such as 2,5-ditertiary-butylhydroquinone.

Examples of the pigment include carbon black, titanium oxide, barium sulfate and the like.

The composition of the present invention is added with various necessary additives, that is, a plasticizer, a stabilizer, a filler, a lubricant, a pigment, a surfactant, and the like, by a conventionally known method using a Banbury mixer, a Henschel mixer, or the like. After being uniformly mixed, they are used after being molded by various conventionally known molding methods.

Since the composition of the present invention contains a polyvinylpyrrolidone and a water-soluble polymer other than polyvinylpyrrolidone, it is considered to shield metal ionic impurities contained in PVC, and therefore the volume resistivity is improved, It is used as a material for wire coatings and terminal adapters that require a large volume resistivity. Further, the metal ionic impurities in PVC are locally present, and therefore the electrical properties are judged to be locally defective, but this local defect is also caused by polyvinylpyrrolidone and polyvinylpyrrolidone. Since it is solved by adding a water-soluble polymer,
The composition of the present invention can be applied to members that require highly uniform electric properties, such as records, video disks, electromagnetic shielding members, and other members that require uniform and high electrical conductivity by adding conductive carbon or the like. Is also preferably used.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. All of these are for explaining the present invention, and not for limiting the scope thereof.

Throughout the examples and comparative examples, the physical properties of vinyl chloride polymers were measured as follows unless otherwise indicated. In addition, a part shows a superposition | polymerization part here.

(B) Volume resistivity: 100 parts of PVC, 50 parts of dioctyl phthalate (DOP) and 3 parts of tribase (tribasic lead sulfate) 150 parts
The mixture was kneaded for 7 minutes with a mixing roll at ℃, and then taken out to obtain a sheet having a thickness of 0.5 mm. A DC voltage of 500 mV was applied to this sheet to determine the volume resistivity (according to the method of JIS K 6723). The unit is Ωcm.

(B) Light transmittance: 100 parts of PVC, 2 parts of cibutyltin mercaptide and 0.5 part of stearic acid were kneaded with a mixing roll at 150 ° C for 10 minutes to obtain a sheet with a thickness of 1.2 to 1.3 mm, which was then pressed to a thickness of 1.0 mm. It was a sheet. The total light transmittance of this sheet was measured by an integrating sphere light transmittance measuring device (JIS K 6717). The unit is a percentage (%).

(C) Haze value: Measured in the same manner as the light transmittance. The unit represents a percentage (%).

(D) Particle size distribution: 100 parts of PVC was placed in a Tyler sieve and hit for 20 minutes, and the weight of the polymer remaining on each sieve was measured to determine the particle size distribution. The unit is the weight fraction (wt%).

Example 1 3,000 kg of deionized water was added to a stainless steel polymerization tank having an internal volume of 7 m ³ .
Vinyl chloride 2,000 kg, t-butyl baroxy pivalate
0.6 kg, hydroxypropyl methylcellulose 0.5 kg, saponification degree 80 mol% partially saponified polyvinyl alcohol 1.5 kg
Was charged and reacted at 57 ° C., and after the polymerization rate of the monomer exceeded 20% and particle formation was completed, 1 kg of a styrene-maleic anhydride copolymer having a molecular weight of 2,500 together with an aqueous solution containing 10 kg of polyvinylpyrrolidone having an average molecular weight of 10,000 was charged. An aqueous solution containing water was added, and the reaction was further continued until the pressure in the polymerization tank reached 5 kg / cm ² G. After the reaction was completed, unreacted monomers were collected, the polymer slurry was discharged, dehydrated and dried to obtain a product, and the volume resistivity and other physical properties were measured by the methods described above. The results are shown in Table 1.

Comparative Example 1 In Example 1, polyvinylpyrrolidone and styrene-
A polymer was obtained in the same manner as in Example 1 except that the maleic anhydride copolymer was not added. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that the styrene-maleic anhydride copolymer was not added. Table 1 shows the physical properties of the obtained polymer.

Example 2 3,000 kg of deionized water was added to a stainless steel polymerization tank having an internal volume of 7 m ³ .
Vinyl chloride 2,000 kg, t-butyl peroxypivalate
0.6 kg, hydroxypropyl methylcellulose 0.5 kg, and hydroxyethyl cellulose 1.5 kg were charged and reacted at 57 ° C., and the reaction was continued until the pressure reached 5 kg / cm ² G. After the reaction was completed, unreacted monomers were collected, and the average molecular weight was 360,000.
An aqueous solution containing 1 kg of hydroxyethyl cellulose was added together with an aqueous solution containing 1 kg of polyvinylpyrrolidone, and after sufficiently stirring, the polymer slurry was discharged, dehydrated and dried to obtain a product. Various physical properties of this polymer are shown in Table 1.

Comparative Example 3 A polymer was obtained in the same manner as in Example 2 except that polyvinylpyrrolidone and hydroxyethyl cellulose were not added. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 4 A polymer was obtained in the same manner as in Example 2 except that hydroxyethyl cellulose was not added. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 5 A polymer was obtained in the same manner as in Example 2 except that polyvinylpyrrolidone was not added. Table 1 shows the physical properties of the obtained polymer.

Example 3 3,000 kg of deionized water was added to a stainless steel polymerization tank having an internal volume of 7 m ³ .
Vinyl chloride 2,000 kg, t-butyl peroxypivalate
0.8kg, hydroxypropylmethylcellulose 0.6kg, saponification degree 80mol% partially saponified polyvinyl alcohol 1.8kg
Was charged and reacted at 53 ° C., and after the polymerization rate of the monomer exceeded 20% and the particle formation was completed, 2 kg of polyvinylpyrrolidone having an average molecular weight of 40,000 and 1 kg of styrene-maleic anhydride copolymer having a molecular weight of 2,500 were contained. The aqueous solution was added, and the polymerization reaction was continued until the inside of the polymerization tank reached 5 kg / cm ² G.

After the reaction was completed, unreacted monomers were collected, the polymer slurry was discharged, dehydrated and dried to obtain a product. Various physical properties of this polymer are shown in Table 1.

Comparative Example 6 Polymerization was carried out in the same manner as in Example 3 except that polyvinylpyrrolidone and styrene-maleic anhydride copolymer were not used in Example 3. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 7 The amount of polyvinylpyrrolidone added in Example 3 was 14 kg.
Polymerization was carried out in the same manner as in Example 3 except that Table 1 shows the physical properties of the obtained polymer.

Example 4 3,000 kg of deionized water was added to a stainless steel polymerization tank having an internal volume of 7 m ³ .
Vinyl chloride 2,000 kg, t-butyl peroxypivalate
0.6 kg, hydroxypropyl methylcellulose 0.6 kg, saponification degree of 80 mol% partially saponified polyvinyl alcohol 1.8 kg
Was charged and reacted at 57 ° C., the average molecular weight was 22 when the polymerization rate of the monomer exceeded 70% and the pressure in the polymerization tank began to decrease.
An aqueous solution containing 0.5 kg of polyvinylpyrrolidone (0.5 kg) and hydroxyethyl cellulose (1.5 kg) was added, and the polymerization reaction was continued until the inside of the polymerization tank reached 6 kg / cm ² G.

After the reaction was completed, unreacted monomers were collected, the polymer slurry was discharged, dehydrated and dried to obtain a product. Various physical properties of this polymer are shown in Table 1.

Comparative Example 8 The average molecular weight of polyvinylpyrrolidone in Example 4 was
Polymerization was carried out in the same manner as in Example 4 except that 2,000 was used. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 9 In Example 4, the addition amount of polyvinylpyrrolidone was 0.05.
Polymerization was performed in the same manner as in Example 4 except that Kg was used. Table 1 shows the physical properties of the obtained polymer.

Comparative Example 10 The average molecular weight of polyvinylpyrrolidone in Example 4 was
Polymerization was carried out in the same manner as in Example 4 except that 630,000 was used. Table 1 shows the physical properties of the obtained polymer.

As can be seen from Table 1, the composition of the present invention has improved volume resistivity without impairing other physical properties.

Claims (1)

[Claims] 1. A process for producing a vinyl chloride-based polymer after polymerization of polyvinylpyrrolidone having an average molecular weight of 10,000 to 360,000 and a water-soluble polymer other than polyvinylpyrrolidone is started to cause a polymerization rate of vinyl chloride to exceed 20%. ,
A vinyl chloride-based polymer composition having a large volume resistivity, which is characterized by adding 50 to 5,000 ppm and 10 to 5,000 ppm to vinyl chloride used for polymerization, respectively.