JP2001011252A - Method for making surface of polyolefin conductive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the surface of a polyolefin semipermanently antistatic by adhering a polypyrrole containing a dopant being a terminal-sulfonated PP to its surface. SOLUTION: The terminal-sulfonated PP as the dopant of a polypyrrole being a conductive polymer has an affinity for a polyolefin, so that it can make the surface of the polyolefin semipermanently conductive. The polypyrrole used is desirably one obtained by polymerization through chemical oxidation with an oxidizing agent being an Fe (III) salt of a terminal-sulfonated PP. To adhere the polypyrrole to the surface of a polyolefin, it is desirable to adopt, for example, a process comprising applying an iron salt of a terminal-sulfonated PP to the surface of the polyolefin and exposing the surface to a vapor of pyrrole to polymerize the pyrrole. The iron salt of the terminal-sulfonated PP is obtained, for example, by reacting styrene with a PP obtained by the living polymerization of propylene to effect its terminal modification, sulfonating the terminal-modified PP, and treating the treating the sulfonated PP with an Fe (III) salt solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for making a polyolefin surface conductive.

[0002]

2. Description of the Related Art Polyolefins are used in films, molded products,
Widely used as molding materials such as fibers. These generally have excellent electrical insulation, waterproofness, chemical resistance, and the like, but have no electrical conductivity, and therefore have a problem that static electricity is easily charged and accumulated, and the surface is easily stained. Was. Therefore, conventionally, as a method for imparting antistatic properties to polyolefin, a method of kneading an antistatic agent into polyolefin, a method of applying an antistatic agent to the surface of a polyolefin molded article, and the like have been used. However, the antistatic agent kneaded into the polyolefin gradually bleeds out, weakening the antistatic effect, and the antistatic agent applied to the product surface is easily removed by friction, etc. There was a problem that it was difficult to maintain the prevention effect.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for imparting conductivity to a polyolefin surface and having semi-permanent antistatic performance.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the present inventors have found that a conductive polymer having a terminal sulfonated polypropylene having a polyolefin surface affinity with polyolefin as a dopant. It has been found that by attaching polypyrrole, conductivity can be imparted to the polyolefin surface and semipermanent antistatic performance can be imparted, and the present invention has been completed.

That is, the present invention is a method for making a polyolefin surface conductive, which comprises attaching polypyrrole using terminally sulfonated polypropylene as a dopant to the surface of the polyolefin.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for making a polyolefin surface conductive by attaching polypyrrole which is a conductive polymer having a terminal sulfonated polypropylene having affinity for the polyolefin as a dopant to the surface of the polyolefin. This will be described in detail below.

[0007] 1. Polyolefin The polyolefin used in the present invention is not particularly limited, and includes known polyolefins. For example, homopolymers such as ethylene, propylene, butene, pentene, hexene, and 4-methyl-pentene-1 or two kinds thereof may be used. The above copolymers are used. Among these polyolefins, preferably, a homopolymer of ethylene or propylene, ethylene and propylene, butene, hexene, 4-
Ethylene copolymers with methyl-pentene-1 or octene; propylene copolymers with propylene and butene, hexene, 4-methyl-pentene-1 or octene. The shape of the polyolefin may be any molded product, and examples thereof include powder, pellets, films, sheets, fibers, nonwoven fabrics, woven fabrics, and various molded products.

[0008] 2. Terminal sulfonated polypropylene The terminal sulfonated polypropylene used in the present invention is a polypropylene-based polymer in which a sulfone group is introduced at the terminal of polypropylene, and is a polypropylene or ethylene-
The propylene random copolymer is a polypropylene whose terminal is modified with a sulfone group and is close to monodisperse. Here, the polypropylene is not limited to a propylene homopolymer, and may be one or more of propylene and another α-olefin (eg, ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, etc.). Block copolymer.

The terminal sulfonated polypropylene used in the present invention may be obtained by any method, but is preferably manufactured by the method described in JP-A-10-168125. . That is,
It is produced by reacting a polypropylene obtained by living polymerization of propylene with a sulfone group-containing monomer in the presence of a catalyst comprising a specific vanadium compound and an organoaluminum compound.

As the vanadium compound which is a catalyst for living polymerization of propylene, V (acetylacetonato) ₃ , V (2-methyl-1,3-butandionato) ₃ , and V (1,3-butandionato) ₃ are preferable.
Further, as the organoaluminum compound, a compound having 1 to 1 carbon atoms
An organoaluminum compound having 8, preferably 2 to 6 carbon atoms, or a mixture or complex compound thereof, such as dialkylaluminum monohalide, monoalkylaluminum dihalide, and alkylaluminum sesquihalide.

The living polymerization reaction is preferably carried out in a solvent which is inert to the polymerization reaction and which is liquid at the time of polymerization. Such solvents include saturated aliphatic hydrocarbons,
Examples include saturated alicyclic hydrocarbons and aromatic hydrocarbons. The amount of the polymerization catalyst used in the polymerization of propylene is 1 × 10 ^{−4 to} 0.1 mol, preferably 5 × 10 ^{−4 to} 5 × 10 ⁻² mol of the vanadium compound per mol of propylene, and 1 mol of the organoaluminum compound. It is from ^{10-4 to} 0.5 mol, preferably from 1 ^{10-3 to} 0.1 mol. The organic aluminum compound is preferably used in an amount of 4 to 100 mol per 1 mol of the vanadium compound.

Living polymerization is usually carried out at a temperature between -100 ° C and 100 ° C.
C. for 0.5 to 50 hours. The molecular weight of the resulting polypropylene can be adjusted by changing the reaction temperature and reaction time. By setting the polymerization temperature to a low temperature, particularly -30 ° C or lower, a polymer having a molecular weight distribution close to monodispersion can be obtained. At −50 ° C. or lower, Mw (weight average molecular weight) / Mn (number average molecular weight) is 1.05 to 1.4.
0 polymer. At the time of the polymerization reaction, a reaction accelerator can be used. Examples of the reaction accelerator include anisole, water, oxygen, alcohol (eg, methanol, ethanol, isopropanol), and ester (eg, ethyl benzoate, ethyl acetate). The amount of the reaction accelerator used is usually 0.001 to 1 mol of the vanadium compound.
2 moles. As described above, about 800-400,
A living polypropylene having a number average molecular weight of 000 and nearly monodispersion can be produced.

Next, in order to introduce a sulfone group structure into the terminal of the polypropylene, the living polymer obtained by the above reaction is reacted with styrene or a derivative thereof to modify the terminal of the polypropylene. By the treatment, a terminal sulfonated polypropylene is obtained. Styrene or its derivatives include styrene,
Examples include divinylbenzene, allylstyrene, butenylstyrene and the like.

The reaction between living polypropylene and styrene or a derivative thereof is carried out by supplying styrene or a derivative thereof to a reaction system in which a living polymer exists, and
Perform at a temperature of 0 ° C. for 5 minutes to 50 hours. By increasing the reaction temperature or increasing the reaction time, it is possible to increase the modification ratio of the polypropylene terminal with styrene or its derivative. Styrene or a derivative thereof is used in an amount of 1 to 1000 mol per 1 mol of living polypropylene.

The reactant of living polypropylene with styrene or a derivative thereof is then contacted with a proton donor. Examples of the proton donor include methanol, ethanol, phenol, hydrochloric acid, sulfuric acid and the like. The contact with the proton donor is usually performed at -100 ° C to 100 ° C for 1 minute to 10 hours. Following the proton donor treatment,
Perform sulfonation. Sulfonation can be performed by a conventional method, for example, a method in which sulfuric acid, fuming sulfuric acid, chlorosulfonic acid is allowed to act on the terminal-modified polypropylene obtained above.

The terminally sulfonated polypropylene obtained as described above has a number average molecular weight (Mn) of about 800 to 500,000, and has a very narrow molecular weight distribution (Mw / Mn) following the polypropylene itself. = 1.
05 to 1.40). In addition, the terminal has an average of 0.1 to 500, preferably 0.5 to 100, sulfone group-containing terminal structures at the terminal. One characteristic of the terminal sulfonated polypropylene thus produced is that the fraction of syndiotactic dyad is 0.6 or more.

3. Production of Polypyrrole Polypyrrole used in the present invention is obtained by doping high-molecular-weight terminal sulfonated polypropylene as an anion during the polymerization of pyrrole. The polymerization of polypyrrole is carried out by a chemical oxidation polymerization method. In general, chemical oxidative polymerization is a polymerization method using an oxidizing agent, in which the oxidizing agent is reduced, and the generated anions are used as dopants. Forms a polymer. In the chemical oxidative polymerization of the polypyrrole of the present invention, when polymerizing pyrrole as a monomer in the presence of an oxidizing agent, terminal sulfonated polypropylene was introduced by using terminal sulfonated polypropylene as an anion constituting the oxidizing agent. Polypyrrole can be obtained.

Examples of the oxidizing agent having terminal sulfonated polypropylene as an anion include transition metal salt compounds such as F.
e (III) salt, Cr (VI) salt and the like. Chemical oxidative polymerization is a method in which pyrrole is dissolved in a solvent and then oxidized by adding an oxidizing agent, a method in which pyrrole is added to a solution containing the oxidizing agent, or a method in which pyrrole is added to a molded article of the oxidizing agent. Examples of the method include contacting with steam.

The solvent used in the chemical oxidative polymerization is not particularly limited as long as it can dissolve polypyrrole. Chlorine solvents such as chloroform and dichloromethane, benzene, toluene, xylene, m-cresol,
Examples thereof include aromatic hydrocarbon solvents such as nitrobenzene, hydrocarbon solvents such as tetrahydrofuran, hexane, and acetonitrile; and polar solvents such as nitrobenzene, N-methyl-2-pyrrolidone, dimethylformamide, and dimethylsulfoxide. The polymerization temperature is -50 to 50.
C, preferably at -40 to 40C.

4. Attachment of polypyrrole to polyolefin The method of attaching polypyrrole obtained as described above to the polyolefin surface is to treat the polyolefin surface with a terminal sulfonated polypropylene, then treat it with a metal ion solution serving as an oxidizing agent, and then polymerize the pyrrole. Alternatively, there is a method in which a metal salt of a terminal sulfonated polyethylene is applied to the surface of a polyolefin, and a polymerization reaction of pyrrole is performed thereon. In particular, when the polyolefin is a film or the like, it is preferable to apply a terminal sulfonated polyethylene metal salt to the surface of the polyolefin film and expose pyrrole vapor on the polyolefin film to perform a polymerization reaction of pyrrole. When the polyolefin is a woven fabric, a nonwoven fabric, or the like, a method of impregnating a polyolefin woven fabric, nonwoven fabric, or the like with a terminal sulfonated polyethylene metal salt solution and exposing the surface to pyrrole vapor to polymerize pyrrole is preferable.

[0021]

The present invention will be described below in detail with reference to examples. The present invention is not construed as being limited to the following examples. The test method in this example is as follows. (1) Surface resistance: measured in accordance with JIS K6911.

Synthesis Example (a) Living Polymerization of Propylene 30 ml of toluene was placed in a 300 ml flask sufficiently purged with nitrogen gas, and cooled to -60 ° C. At this temperature, 200 mmol of liquefied propylene was added and dissolved in toluene. Then, 15 mmol of Al (C ₂ H ₅ ) ₂ Cl
And 1.5 mmol of a toluene solution of V (2-methyl-1,3-butanedionate) ₃ were added, and polymerization was started with stirring. Polymerization of propylene
Performed at 60 ° C. for 1 hour.

(B) Reaction with styrene 7 mmol of styrene was added to the above reaction system at -60 ° C, and reacted at the same temperature for 30 minutes. Thereafter, the reaction solution was poured into 500 ml of ethanol to precipitate a polymer. The precipitate was dissolved in n-hexane, and a supernatant was obtained by centrifugation. 500 ml of this supernatant
Was poured into methanol to precipitate the polymer again. The obtained polymer was washed five times with methanol, and dried under reduced pressure at room temperature to obtain 1.47 g of a polymer. The molecular weight and molecular weight distribution of the obtained polymer were measured by GPC (gel permeation chromatography) model 150 (Wa).
ters). Using o-dichlorobenzene as a solvent, measurement temperature 135 ° C., solvent flow rate 1.0
Performed at ml / min. The column is GMH6HT (trade name,
Tosoh Corporation) was used. In the measurement, a standard curve of polystyrene was prepared using a monodisperse polystyrene standard sample manufactured by Tosoh Corporation. Thus, a calibration curve of polypropylene was prepared by the universal method. The GPC runoff curve of the resulting polymer was unimodal. The number average molecular weight (Mn) of this polymer was 4.2 × 10 ³ , and the molecular weight distribution (weight average molecular weight / number average molecular weight = Mw / Mn) was 1.34, a value close to monodispersion.

(C) Determination of Structure of Polymer The structure of the obtained polymer was determined by IR and NMR as follows. IR: Model IR manufactured by JASCO Corporation
-810 (trade name) was measured by a liquid film method (KBr plate) using an infrared spectrophotometer. Absorption near 1600 cm ^-1 based on the stretching vibration of the CC bond of the benzene ring, and absorption near 700 cm ^-1 based on the out-of-plane bending vibration of CH were observed. ¹ H-NMR: GSX-400 (trade name) manufactured by JEOL Ltd.
Using a Fourier transform type NMR spectrometer, 40
The measurement was performed under the conditions of 0 MHz, 30 ° C., and a pulse interval of 15 seconds. The sample was prepared by dissolving in deuterated chloroform. Peaks attributed to protons of polypropylene (δ = 0.7 to
In addition to the peak (1.7 ppm), a peak (δ = 6.3 to 7.3 ppm) due to a proton on the benzene ring of styrene was observed. Proton signal (δ
= 0.7 to 1.7 ppm) and the area ratio between the peak signal attributable to the proton of the benzene ring of styrene and
The resulting polymer was found to have an average of 7 styrene units introduced at the end of the polypropylene.

(D) Sulfonation reaction In a 300 ml flask sufficiently purged with nitrogen gas, 1.0 g of the polymer obtained above and 100 ml of chloroform were placed.
And the polymer was dissolved in chloroform. This was cooled to −8 ° C. and stirred, and 1 mmol of chlorosulfonic acid was added, and the mixture was reacted at this temperature for 2 hours. Then, 1 mol /
One liter of an aqueous sodium hydroxide solution (5 ml) was added, and the mixture was further reacted for 1 hour. The solution was washed five times with water and then poured into one liter of methanol to precipitate and recover the polymer. The recovered polymer was dried under reduced pressure at room temperature. Elemental analysis of the obtained polymer showed that
The S content was 2.5% by weight. That is, 53 mol% of the styrene units introduced into the terminals were sulfonated (terminal sulfonated polypropylene).

Example 1 (1) Synthesis of Iron Salt of Terminal Sulfonated Polypropylene A sufficiently dried three-necked flask was equipped with a stirrer and a dropping funnel, and after purging with nitrogen, toluene of the terminal sulfonated polypropylene obtained in Synthesis Example was used. Solution (10% by weight)
In a 0 ml flask, put a toluene solution of FeCl ₃ (2
200% by weight) was added dropwise at room temperature. After dropping, 1
After stirring for an hour, the solution was dropped into 1000 ml of methanol, and the precipitated yellow polymer was recovered. Furthermore, after washing with methanol three times, it was dried under reduced pressure. After drying,
9 g of a terminal sulfonated polypropylene iron salt were obtained.

(2) Polymerization of pyrrole on film Terminal-sulfonated polypropylene iron salt obtained in (1) 1
g was dissolved in 100 ml of toluene, applied to a polypropylene film, and dried. After drying, at room temperature, put a polypropylene film coated with terminal sulfonated polypropylene iron salt in a desiccator filled with pyrrole vapor,
It was exposed to pyrrole vapor for 30 minutes to carry out polymerization. After 30 minutes, it was taken out of the desiccator, washed with methanol, and dried under reduced pressure for 2 hours. After 2 hours, the surface resistance of the polypropylene film was measured to be 10 ⁵ Ω / cm.
It was ² .

Example 2 A conductive film was obtained in the same manner as in Example 1 except that a polyethylene film was used instead of the polypropylene film. When the surface resistance of the obtained polyethylene film was measured, it was 10 ⁵ Ω / cm ² .

Example 3 In the same manner as in Example 1, the synthesized terminal-modified sulfonated polypropylene iron salt was dissolved in toluene, impregnated in a polypropylene nonwoven fabric, and dried under reduced pressure. After the drying was completed, the nonwoven fabric was put in a desiccator filled with pyrrole vapor at room temperature, and exposed to pyrrole vapor for 30 minutes to perform polymerization. 30
After a minute, it was taken out of the desiccator, washed with methanol, and dried under reduced pressure for 2 hours. After 2 hours, the surface resistance of the polypropylene nonwoven fabric was measured to be 10 ⁶ Ω / cm ²
Met.

Example 4 A conductive treated film was obtained in the same manner as in Example 3, except that a polypropylene microporous film was used instead of the polypropylene nonwoven fabric. When the surface resistance of the obtained polypropylene microporous film was measured, it was 10 ⁴ Ω / cm ² .

Example 5 The terminal-modified sulfonated polypropylene obtained in the synthesis example was dissolved in toluene, applied on a polypropylene film, and dried under reduced pressure. After drying, it was immersed in an aqueous solution of iron (III) chloride for 1 hour at room temperature and dried. After drying, put the polypropylene film in a desiccator filled with pyrrole vapor at room temperature and expose it to pyrrole vapor for 30 minutes,
Polymerization was performed. After 30 minutes, it was taken out of the desiccator, washed with methanol, and dried under reduced pressure for 2 hours. Two hours later, the surface resistance of the polypropylene film was measured and found to be 10 ⁵ Ω / cm ² .

Comparative Example The polypropylene film used in the examples
Tylene film, polypropylene non-woven fabric, polypropylene
The surface resistance of the microporous film was as follows. Polypropylene film: 10¹⁶Ω / cm²  Polyethylene film: 10¹⁶Ω / cm²  Polypropylene non-woven fabric: 10¹⁶Ω / cm²  Polypropylene microporous film: 10¹⁶Ω / cm²

[0033]

According to the method for making a polyolefin surface conductive according to the present invention, the surface resistance of ordinary polyolefin is 10%.
^{While the} resistance is ¹⁶ Ω / cm ² , the surface resistance of the polyolefin can be reduced to 10 ⁶ to 10 ⁴ Ω / cm ^2, and its use is very large industrially.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masami Kizaki 371 Nakafukuoka, Kamifukuoka City, Saitama Prefecture (72) Naomi Murakami 125-1-102 Sunatsuda, Kawagoe City, Saitama F-term (reference) 4J002 BB031 BB051 BB121 BB141 BB151 BB171 BB262 CM023 FD113

Claims (2)

[Claims] 1. A method for making a polyolefin surface conductive, comprising attaching polypyrrole using terminally sulfonated polypropylene as a dopant to the surface of the polyolefin. 2. The method according to claim 1, wherein the polypyrrole is polypyrrole obtained by chemical oxidative polymerization using Fe (III) salt of terminal sulfonated polypropylene as an oxidizing agent.