JPH06212096A - Antistatic agent - Google Patents

Abstract

PURPOSE:To obtain an antistatic agent giving a stable antistatic coating film by polymerizing acrylic acid, etc., and a water-soluble crosslinking monomer in the presence of a specific phenolsulfonic acid cyclic derivative, copolymerizing the obtained copolymer with vinyl acetate and using the produced copolymer as a component. CONSTITUTION:A reaction vessel is charged with a phenolsulfonic acid cyclic derivative expressed by the formula ((n) is integer of 4-8) or its salt together with water. A mixed aqueous solution of acrylic acid, sodium acrylate and a water-soluble crosslinking monomer (e.g. methylenebisacrylamide) and an aqueous solution of ammonium persulfate as a water-soluble polymerization initiator are charged to the reaction vessel and subjected to polymerization reaction at 82-84 deg.C for 1hr to obtain an aqueous solution of a copolymer. The aqueous solution of copolymer is incorporated with vinyl acetate and an aqueous solution of ammonium persulfate and made to react with each other under nitrogen gas stream at 70-72 deg.C for 1hr to obtain a uniformly emulsified emulsion polymer. The emulsion polymer is compounded with ethyl alcohol denatured with 10% isopropyl alcohol to obtain the objective antistatic agent capable of forming a stable coating film on a plastic surface.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an antistatic agent. More specifically, a copolymer obtained by further copolymerizing vinyl acetate with a copolymer of acrylic acid or a salt thereof and a water-soluble crosslinking agent monomer, wherein the polymer contains a phenol sulfonic acid cyclic derivative in the molecule. The present invention relates to an antistatic agent as an active ingredient, which is soluble in aqueous alcohol and has a quick-drying film-forming property.

[0002]

2. Description of the Related Art A plastic material has a drawback that it is easily charged with static electricity due to friction and the like, which causes dust adhesion and electrostatic damage. To avoid this disadvantageous property, it is known to provide plastic surfaces with a thin surface coating of antistatic agent. In many cases, the antistatic agent used is a water-soluble compound such as a surfactant, and the film formed using these is easily mechanically worn and washed off with water, so the antistatic effect can be easily obtained. Is lost.

[0003]

[Problems to be Solved by the Invention]
A method for forming a polymer film having an antistatic property on the surface of plastic has been proposed (JP-A-63-68676).
(See Japanese Patent Publication). However, this method uses a mixture of a polymeric substance having film-forming properties such as cellulose ester and a conventional surfactant-based antistatic agent to form an antistatic film on the plastic surface, There is a problem that the antistatic agent bleeds over time and the surface becomes sticky. In order to solve the above-mentioned drawbacks of the conventional technique,
The present inventors have proposed a polymer antistatic agent capable of forming an antistatic film on the surface of plastic or the like (Japanese Patent Application No. 4-298052). This polymeric antistatic agent is excellent in antistatic properties, has water solubility, and can be used as an aqueous solution, and is therefore advantageous in terms of occupational hygiene and pollution prevention. However, there is a problem that quick-drying property is required for some applications, and it is difficult to use the above antistatic agent for such applications. The present invention was devised to solve the above-mentioned problems, and has a characteristic that a stable antistatic coating is provided on a plastic surface and that a polymer substance soluble in an alcohol solvent is used as an active ingredient. The purpose is to provide an inhibitor.

[0004]

The antistatic agent of the present invention, which has been made to solve the above problems, acts as a chain transfer agent, represented by the following general formula (1): Acrylic acid and / or a salt thereof (hereinafter referred to as acrylic acid) and a water-soluble crosslinking agent in the presence of a compound represented by the formula (in the formula, n is an integer of 4 to 8) and / or a salt thereof. A copolymer obtained by polymerizing vinyl acetate with a copolymer obtained by radical copolymerization with a monomer in an aqueous system (hereinafter referred to as copolymer 1) (hereinafter referred to as copolymer 2)
Is an active ingredient. That is, the copolymer 1 is an active ingredient of the antistatic agent disclosed in Japanese Patent Application No. 4-298052, and vinyl acetate is radically polymerized with this.
The compound represented by the general formula (1) is incorporated as a constituent component in the copolymer 1, and since this skeleton acts as a chain transfer agent, the copolymer 1 is chain-transfer copolymerized with vinyl acetate. Copolymer 2 is obtained.

The present invention has the above-mentioned constitution, and the copolymer 1 which is a raw material for producing the copolymer 2 which is the active ingredient of the antistatic agent of the present invention is disclosed in Japanese Patent Application No. 4-298052. In the presence of the compound represented by the general formula (1) which is a chain transfer agent and / or a salt thereof, the acrylic acid and the water-soluble crosslinking agent monomer are According to the method, it is obtained by radical copolymerization in an aqueous solvent under an inert gas atmosphere.

The compounds represented by the general formula (1) and salts thereof used here are known compounds and are disclosed, for example, in JP-A-61-83156, and the method described therein. Can be prepared at. Examples of the salt of the compound represented by the general formula (1) include alkali metal salts (eg sodium salt, potassium salt etc.), alkaline earth metal salts (eg magnesium salt, calcium salt etc.).
Inorganic metal salt, ammonium salt, organic base salt (eg, trimethylamine salt, triethylamine salt, ethanolamine salt, triethanolamine salt, piperazine salt, piperidine salt, morpholine salt, N-methylmorpholine salt, pyridine salt, picoline) Examples thereof include salts, N-methylpyridinium salts, 2-dimethylaminoethanol salts, etc., salts with amino acids (eg, lysine salts, arginine salts, etc.), and alkali metal salts are preferred. In addition, the salt of the compound represented by the general formula (1) includes both a compound in which all the sulfo groups of the compound represented by the general formula (1) are neutralized and a compound in which a part thereof is neutralized. Included. Further, the phenolic hydroxyl group in the compound represented by the general formula (1) may be neutralized.

Acrylic acid, which is a main raw material monomer of the copolymer 1, can be used in the form of a free acid, a salt or a mixture thereof, and examples of the acrylate include those exemplified above. Although a salt is mentioned, an alkali metal salt is particularly preferably used. As the water-soluble crosslinking agent monomer, any one can be used as long as it is a water-soluble monomer capable of radical polymerization and can be a crosslinking agent, but N, N'- which has excellent copolymerizability with acrylic acids. Methylenebisacrylamide and ethylene glycol diacrylate are preferably used.

The above-mentioned polymerization reaction can be carried out in accordance with ordinary radical polymerization, and any initiator can be used as long as it is used in aqueous radical polymerization, for example, persulfate. Examples include system initiators (eg, potassium persulfate, ammonium persulfate, etc.), redox system initiators (eg, hydrogen peroxide-ferrous salt, etc.), and the like. Regarding the charging ratio of each of the above components, acrylic acid is about 50 to 500 times mol, preferably 100 to 30 with respect to the total amount of the compound represented by the general formula (1) and a salt thereof.
The molar ratio is about 0 times, more preferably about 200 times. The amount of the water-soluble crosslinking agent monomer is 0.05 to 1 with respect to the total amount of the compound represented by the general formula (1) and a salt thereof.
The molar ratio is about 0 times, preferably about 0.1 to 5 times, and more preferably about 0.5 to 2 times.

More specifically, for example, a predetermined amount of the compound represented by the general formula (1) and / or its salt is dissolved in water and the temperature is raised to 80 to 90 ° C. under a nitrogen stream. At this temperature, an aqueous solution in which a predetermined amount of acrylic acid and a water-soluble crosslinking agent monomer are dissolved and an aqueous solution in which an initiator is dissolved are simultaneously and slowly dropped into this solution to initiate polymerization. After completion of the dropping, the copolymer 1 is obtained by aging at the same temperature (usually about 30 minutes to 1.5 hours). In the obtained copolymer 1, a basic substance such as sodium hydroxide may be used to neutralize the acid groups present in the copolymer, if necessary. The copolymer 1 thus obtained may be purified by a conventional method such as dialysis or reprecipitation, or may be directly used as a raw material in the next reaction without purification.

The copolymer 1 obtained above is subjected to radical copolymerization with vinyl acetate in an aqueous solvent to obtain a copolymer 2 which is an active ingredient of the antistatic agent of the present invention. Examples of the initiator used in this reaction include the above radical initiators, and persulfate initiators are preferably used. The amount of vinyl acetate used relative to copolymer 1 is about 0.5 to 10 times by weight vinyl acetate based on copolymer 1, preferably about 1.5 to 4 times by weight, and more preferably 2 to 3 times by weight. It is about doubled. If the amount of vinyl acetate used is less than 0.5 times by weight, the solubility in alcohol is insufficient, and if it exceeds 10 times by weight, the antistatic performance may be poor. More specifically, in the above-mentioned polymerization reaction, for example, a predetermined amount of the copolymer 1 is dissolved in water and the temperature is raised to about 70 to 80 ° C under a nitrogen stream. To this solution at the same temperature,
An aqueous solution in which a predetermined amount of vinyl acetate monomer and an initiator are dissolved is slowly added dropwise at the same time to start polymerization. After completion of the dropping, the emulsion of the copolymer 2 is obtained by aging at the same temperature (usually about 30 minutes to 1.5 hours). The copolymer 2 thus obtained may be purified and used by a conventional method such as dialysis or reprecipitation, or may be directly used as an antistatic agent without purification.

The antistatic agent of the present invention can be used in the same manner as a conventional antistatic agent, but in a preferred embodiment, it is prepared as a hydroalcoholic solution of the copolymer 2 and used in the preparation of plastics, synthetic fibers and the like. Used as a quick-drying surface coating type antistatic agent for molecular materials and products. The aqueous alcohol solution of the copolymer 2 may be used by dissolving the solid substance of the copolymer 2 in the aqueous alcohol at the time of use. A solution prepared by adding alcohol to an aqueous alcohol solution may be used. Examples of the alcohol used here include ethyl alcohol and isopropyl alcohol-modified ethyl alcohol. As the alcohol content of the hydroalcoholic solvent,
About 50 to 95 (w / w)%, preferably 60 to 70
(W / w)%. The antistatic agent of the present invention can be used by, for example, applying the aqueous alcohol solution of the above-mentioned copolymer 2 to the surface of a plastic material such as polyethylene, ABS, polyester, polycarbonate, or polyvinyl chloride, and spraying it. And then dried to form an antistatic coating. The amount of antistatic agent used depends on the type of plastic material,
It is appropriately adjusted depending on the purpose of use.

[0012]

The present invention will be described in more detail based on the following examples and test examples, but the present invention is not limited to these examples. In the following examples, the sodium salt of the compound represented by the general formula (1) was used.
The properties of the compounds used are shown in Table 1. In Table 1 and the following description, CALX-SN is used as an abbreviation for the sodium salt of the compound represented by the general formula (1), and n is 4 in the compound represented by the general formula (1). Is represented by CALX-S4. Similarly, the sodium salt of the compound in which n is 6 is represented by CALX-S4.
6, the sodium salt of the compound in which n is 8 is CALX-S
Displayed at 8.

[0013]

[Table 1]

Production Example 1 35 g of water and 1.271 g of CALX-S4 were placed in a reaction vessel equipped with a stirrer, a thermometer, a dropping device and a reflux condenser.
Was charged, and the temperature was raised to 82 to 84 ° C. under a nitrogen stream. To this solution, 62.6 g of water, sodium acrylate 18.
A mixed aqueous solution of 28 g, 6 g of acrylic acid and 0.2127 g of methylenebisacrylamide (hereinafter referred to as MBAD) and 4 g of a 5 wt% ammonium persulfate aqueous solution were simultaneously added dropwise at 82 to 84 ° C. in 2 hours. As the dropping proceeded, the polymerization reaction proceeded and the viscosity of the reaction system increased. After completion of the dropping, a copolymer (hereinafter referred to as CALX4PA) is obtained by aging the polymerization reaction at 82 to 84 ° C. for 1 hour.
An aqueous solution was obtained. The reaction system was a pale yellow transparent viscous homogeneous aqueous solution. Sampling a part of the reaction system, 70
When the polymerization rate was obtained by drying to constant weight under reduced pressure at ℃,
The polymerization is almost quantitative,> 99%. The solid content concentration was about 20% by weight, and the pH was 6-7. The charged molar composition of this reaction system is as follows.

Production Example 2 Copolymerization was performed in the same manner as in Production Example 1 except that 2-dimethylaminoethanol salt of acrylic acid was used in place of sodium acrylate in Production Example 1, to obtain a copolymer (hereinafter referred to as CALX4PAE1). An aqueous solution was obtained.

Preparation Example 3 Preparation Example 3 except that the triethanolamine salt of acrylic acid was used in place of sodium acrylate in Preparation Example 1 and that the charged mole fraction of the acrylate based on all acrylic acid monomers was 50%. Copolymerization was performed in the same manner as in 1 to obtain a copolymer (hereinafter referred to as CALX4PAE3) aqueous solution.

Example 1 In a reaction vessel equipped with a stirrer, a thermometer, a dropping device and a reflux condenser, 76.9 g of water and an aqueous CALX4PA solution 1
1.9 g (concentration: 20.23%, CALX4PA content:
2.41 g) was charged and the temperature was raised to 70 to 72 ° C. under a nitrogen stream. To this solution, at 70 to 72 ° C., 6.2 g of vinyl acetate and 1 g of a 1% by weight ammonium persulfate aqueous solution were simultaneously added dropwise from individual dropping devices over 1 hour. As the dropping proceeded, the polymerization reaction proceeded, and a uniformly emulsified emulsion polymer was produced. 70 to 72 after completion of dropping
A uniform emulsion of the copolymer (hereinafter referred to as CALX4PA-PVAc) was obtained by aging the polymerization reaction at 0 ° C. for 1 hour. Sampling a part of the reaction system,
When the polymerization rate was determined by drying at 0 ° C. under reduced pressure to a constant weight, the polymerization rate was almost quantitative and was 99% or more. The solid content concentration was about 8.7% by weight, and the pH was 6-7. To the above CALX4PA-PVAc emulsion,
A hydroalcoholic solution was prepared by adding 10% denatured ethyl alcohol to isopropyl alcohol. The properties are shown in Table 2.

Example 2 Instead of the CALX4PA of Example 1, the CALX4PAE1 obtained in Production Example 2 and the CALX obtained in Production Example 3 were used.
Copolymerization was performed in the same manner as in Example 1 except that 4PAE3 was used to obtain each copolymer emulsion.
The copolymer obtained from CALX4PAE1 was used as CALX4.
It is called PAE1-PVAc, and the copolymer obtained from CALX4PAE3 is called CALX4PAE3-PVAc. The obtained copolymer emulsion was added with 10% isopropyl alcohol-modified ethyl alcohol in the same manner as in Example 1 to prepare a hydroalcoholic solution. The properties are shown in Table 2.
Are also shown.

[0019]

[Table 2]

Test Example CALX4PA-PVAc and CALX4 shown in Table 2
PAE1-PVAc and CALX4PAE3-PVAc
Apply the hydroalcoholic solution of to the plastic surface,
After drying, antistatic performance was evaluated. The results are shown in Table 3.
And shown in Table 4. The details of the test are as follows.

Plastic material used: High impact polystyrene (HI-PST): HI-PST
Was pressed at 175 ° C. and 15 kg / cm ² to prepare a sheet having a thickness of 0.1 cm. ABS: ABS pellets at 175 ° C., 15 kg / c
A sheet having a thickness of 0.1 cm was prepared by pressing at m ² . PET: A commercially available PET sheet was used. Polycarbonate: A commercially available polycarbonate sheet was used. PVC: A commercially available PVC sheet was used. Note that none of the above materials has an antistatic agent added.

Coating method: A 15 cm × 15 cm sheet was uniformly coated with a hydroalcoholic solution containing about 1.0 to 1.5 g of a test antistatic agent, and then dried in a fume hood at room temperature for 30 minutes. At this time, the tackiness of the sheet surface was examined, but no tackiness was observed. Next, this coating sheet was left for 12 hours or more in a constant temperature and constant humidity chamber (temperature 25 ° C., humidity 50%), and then subjected to measurement. Even at this time, no tackiness on the sheet surface was observed.

Measurement of specific surface resistivity: TERA OHM METER (model VE-30) in a constant temperature and constant humidity chamber.
S, manufactured by Kawaguchi Electric Co., Ltd.) and applied voltage 5 according to a conventional method.
The surface resistivity was measured at 00V.

Measurement of high electrostatic field charging half-life: In a constant temperature and humidity chamber, a static meter (S-4104, manufactured by Nippon Static Co., Ltd.) was used to charge at 10 kV according to a conventional method, and then the degree of attenuation was determined. (Half-life) was measured.

Measurement of friction electrification voltage: Using a Kyoto University Kaken rotary static tester (manufactured by Koa Shosha Co., Ltd.) in a constant temperature and constant humidity chamber, a sample plastic sheet was rotated at a high speed, and a cotton cloth with a coated surface left standing. The surface was rubbed and the frictional electrification voltage (V) was measured.

[0026]

[Table 3]

[0027]

[Table 4]

As shown in Tables 3 and 4, the plastics on which the antistatic agent film of the present invention is formed have lower surface resistivity, half-life and frictional electrification voltage than those of the blanks. It was revealed that the antistatic agent has excellent antistatic ability. In particular, No. When the sample of 606-K was applied to HI-PST and ABS, the surface resistivity was in the order of 10 ⁹ Ω / □, and good antistatic property was exhibited. Further, although it is slightly inferior in performance, it was clarified that it has antistatic properties even when the neutralizing base of the acrylic acid moiety is triethanolamine or 2-dimethylaminoethanol. All had good film forming ability.

The antistatic effect of such a copolymer 2 is as follows.
It is considered to be caused by the copolymer 1, and it is presumed that the copolymer was copolymerized with vinyl acetate to impart solubility to alcohol. By the way, CALX4P
A, CALX4PAE1 and CALX4PAE3 are sparingly soluble in alcohol, and when alcohol is added to an aqueous solution of these to make an aqueous alcohol solution as shown in Table 2, precipitation occurs. On the other hand, as shown in Table 2, in Copolymer 2, since precipitation did not occur even if alcohol was added, a copolymer of Copolymer 1 and vinyl acetate was produced. It was found to be not a mixture of polyvinyl acetate and polyvinyl acetate. In addition, CALX-SN
Is stable in the aqueous radical polymerization reaction at a temperature of 70 to 90 ° C.
This is shown in Japanese Patent Publication No. 100890.

[0030]

As described above, the antistatic agent of the present invention is
It has excellent antistatic properties and can be prepared into a hydroalcoholic solution, and a stable antistatic coating can be formed on the plastic surface by coating and drying on the plastic surface, resulting in high workability. .

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C09K 3/16 102 H 108 (72) Inventor Yoshiaki Matsumoto 4-4-6 Usu, Wakayama Sugai Chemical Industrial Co., Ltd. In the company

Claims (3)

[Claims] 1. The following general formula (In the formula, n represents an integer of 4 to 8.) A copolymer obtained by polymerizing acrylic acid or a salt thereof and a water-soluble crosslinking agent monomer in the presence of a compound or a salt thereof, and vinyl acetate. An antistatic agent containing a copolymer of and as an active ingredient. 2. The antistatic agent according to claim 1, wherein the dosage form is a hydroalcoholic solution. 3. The antistatic agent according to claim 2, which is a surface coating type antistatic agent for polymer materials and products.