JPH06807B2 - Method for making halogen-containing polymer conductive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for making a halogen-containing polymer conductive.

(Prior Art) As a method for producing a polyene polymer by dehydrochlorination of a halogen-containing polymer such as polyvinyl chloride, the halogen-containing polymer is dispersed in an aqueous medium containing an inorganic base such as sodium hydroxide and heated under pressure. Dehalogenation or dehydrohalogenation (JP-A-49-112979), a method of heating a chlorine-containing polymer to 160 to 300 ° C. in an aqueous solution of sodium hydroxide or the like to which an acid amide as a catalyst is added ( JP-A-50-121390),
A method for producing dehydrohalogenation of a halogen-containing polymer using an aqueous alkali solution and a phase transfer catalyst (JP-A-58)
-142905), a method of dehydrochlorinating a vinyl chloride resin by heating it in the presence of concentrated sulfuric acid having a concentration of 90% or more at a temperature of 150 ° C to the boiling point of the sulfuric acid (Japanese Patent Publication No. 53-12552). There is.

(Problems of the prior art) These methods require severe reaction conditions such as high temperature and high pressure, or the obtained polyene-bonded polymer has insufficient conductivity, and When left in the air, there is a problem that it gradually turns red (oxidation stability is poor).

(Problems to be Solved by the Invention) The present invention has been intensively studied to develop a method for converting a halogen-containing polymer into a polyene polymer having excellent conductivity by a simple treatment without such a problem. It was surprisingly found that extremely excellent conductivity can be obtained by treating a halogen-containing polymer with sulfur trioxide known as a dopant, and the present invention has been completed based on this finding.

(Means for Solving the Problems) The present invention provides a method for making a halogen-containing polymer conductive by treating the halogen-containing polymer with sulfur trioxide.

As the halogen-containing polymer used in the present invention, vinyl chloride, vinyl bromide, vinyl halide homopolymers such as vinyl fluoride, vinylidene chloride, vinylidene bromide, vinylidene halide homopolymers such as vinylidene fluoride. , Vinyl halide-vinylidene halide copolymers, vinyl halides or vinylidene halides and other monomers copolymerizable therewith, such as vinyl acetate, acrylic acid, methacrylic acid or esters of these acids, acrylonitrile , Copolymers with at least one kind of styrene (random and block, graft), polychloroprene, tetrafluoroethylene / propylene fluorine rubber,
Vinylidene fluoride / hexafluoropropylene-based fluorocarbon rubber,
Examples thereof include fluorocarbon rubbers such as tetrafluoroethylene / perfluoroalkyl perfluorovinyl ether system / fluorocarbon rubbers and halogenated polymers such as chlorinated polyethylene. These polymers can be used alone or as a mixture. Also, a mixture of a halogen-containing polymer and a halogen-free polymer, such as polyvinyl chloride and A
It can also be used as a mixture with a BS resin, a mixture of polyvinyl chloride and an acrylonitrile-butadiene copolymer rubber, and the like. The halogen-containing polymer is not limited to the above examples, but it is preferable to increase the chain length of the polyene bond in order to increase the conductivity, and a halogen-containing monomer and a halogen-free monomer As for the copolymer (1), the chain length of the polymer block of the halogen-containing monomer in the copolymer chain is desired to be as long as possible, and the degree of polymerization is preferably at least 20. The content of the halogen-containing monomer in the copolymer is preferably 10 mol% or more.

Examples of the sulfur trioxide used in the present invention include sulfur trioxide, fuming sulfuric acid containing sulfur trioxide, and a compound that decomposes to produce sulfur trioxide, such as sulfur trioxide.

Treatment of the halogen-containing polymer with sulfur trioxide is accomplished, for example, by contacting the solid or solution polymer with sulfur trioxide.

The method for treating the halogen-containing polymer in the solid state (for example, film, molded article, powder, etc.) is (1) contacting the polymer with vapor of sulfur trioxide (2) liquid or trioxide of sulfur trioxide Examples include a method of immersing the polymer in a dispersion or solution of sulfur in an organic or inorganic solvent that does not react with sulfur trioxide in a poor solvent for the polymer (a solvent in which the polymer swells does not matter) To be done.

As a method for treating the halogen-containing polymer in a solution state, (1) blowing sulfur trioxide vapor into a solution of the halogen-containing polymer (using a good solvent for the polymer that does not react with sulfur trioxide as a solvent) Examples of the method include (2) a method of dissolving or dispersing sulfur trioxide in a solution of a halogen-containing polymer.

The polyene polymer precipitates in the dissolved state treatment.

The treatment conditions depend on the kind of the halogen-containing polymer, the concentration of sulfur trioxide, etc., but are usually several seconds to several tens hours at room temperature. The treatment temperature is not limited to room temperature, but may be in the range of room temperature to 100 ° C. Conductivity cannot be obtained by treatment with concentrated sulfuric acid at such a temperature. The conductivity of 10 ^-2 to 10 ^-6 S / cm can be obtained by changing the processing conditions.

After completion of the treatment, the polymer such as film or the powdery polymer separated therefrom is thoroughly washed with alcohol or water and dried.

The polyene polymer thus obtained has extremely excellent conductivity and is extremely stable against oxidation.

Further, the dopants usually used for enhancing conductivity can be doped by chemical doping and electrochemical doping.

As the dopant, known dopants disclosed in JP-A-58-206065 can be used.

The present invention will be specifically described below with reference to examples.

Example 1 Film of polyvinyl chloride (polymerization degree: 1300) (prepared by Solpent cast method, 20 mm width × 20 mm length × 0.2 m
(thickness) was placed in a glass reaction vessel equipped with a two-way cock, deaerated with a vacuum pump, and then SO ₃ vapor was introduced through a trap cooled with dry ice-methanol to be saturated with SO ₃ vapor. . The experiment was repeated by changing the standing time at room temperature. The film turned black immediately upon contact with SO ₃ vapor.

For comparison, dehydrochlorination was carried out using 1,8-diazabicyclo [5,4,0] undecene-7 (DBU).

Diisopropyl ether / 1,2-dimethoxyethane (4
(1 / weight ratio) The above polyvinyl chloride is dissolved in a mixed solvent, and 5 mol of DBU is added to 1 mol of polyvinyl chloride,
It was treated with stirring at 50 ° C. for 5 hours. After the treatment, the precipitated polyene polymer powder was separated, thoroughly washed with methanol, and dried. A 0.2 mm thick sheet was formed by hot pressing.

DC microvolt ammeter (Toa Denpa Co. PM-1
8R) and was measured at room temperature by the two-terminal method. The results are shown in Table 1.

Unreacted polyvinyl chloride was removed from the test piece of Experiment No. 4 by washing with dimethoxyethane, and then elemental analysis was performed. As a result, the polymer obtained by treating polyvinyl chloride with SO ₃ (The number in the formula represents% by weight, and ↓ indicates that it is doped).

Example 2 A film of a salt bee vinegar picopolymer (vinyl acetate content: 23% by weight) was treated with SO ₃ vapor for 20 hours in the same manner as in Example 1. The conductivity of the treated film was measured in the same manner as in Example 1 and a result of 1.8 × 10 ^-2 S / cm was obtained.

Example 3 A sheet (20 mm ×) of a 50/50 (weight ratio) mixture of ABS resin and polyvinyl chloride resin (AL-4003 manufactured by Zeon Kasei Co., Ltd.)
(20 mm length × 0.5 mm thickness) was treated with SO ₃ vapor for 20 hours in the same manner as in Example 1.

The conductivity after the treatment was 5.3 × 10 ^-2 S / cm.

Claims (1)

[Claims] 1. A method for making a halogen-containing polymer conductive, which comprises treating the halogen-containing polymer with sulfur trioxide.