JPH09188873A - Antistatic agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antistatic agent which develops good antistatic properties even when added in a small amount and has good resistance to water washing by using a salt of a specified sulfonated styrene polymer with an organic base. SOLUTION: A sulfonating agent is introduced into a solution prepared by dissolving 100 pts.wt. styrene polymer having a weight-average molecular weight of 1,000-50,000 and a molecular weight distribution (Mw/Mn) of 2.0-2.8, 0.1-10 pts.wt. ether compound and/or carbonyl compound in a halohydrocarbon solvent to sulfonate the styrene polymer, and the reaction mixture is neutralized to obtain a sulfonated styrene polymer having a weight-average molecular weight of 3,000-300,000 and a molecular weight distribution (Mw/Mn) of 2.0-2.8. This polymer is reacted with an organic base comprising tert. and/or quat. amines each of which has a 6C or higher hydrocarbon group to form a product which has a degree of sulfonation of 30% or above and in which 70-100% of the sulfonic groups of the polymer are in the form of a salt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antistatic agent, and more particularly to an antistatic agent having excellent water wash resistance as a kneading type antistatic agent for plastics.

2. Description of the Related Art Plastic materials have been used in a wide range of fields due to their excellent properties, but because they are electrically insulating, they are apt to be electrostatically charged, and as a result, dust adheres to the molded product and damages its appearance. When used in cases or parts of electric / electronic equipment, malfunction or IC of equipment due to discharge
It also causes the destruction of the. For this reason, studies for improving the antistatic property of plastics have been actively pursued. In order to impart antistatic properties to plastics, a method of adding a surfactant type antistatic agent is generally used. In this case, although the short-term antistatic property after molding is excellent, long-term It is difficult to maintain the antistatic property, and there is a problem that the performance sharply deteriorates especially after washing with water. In addition, a method of kneading a conductive inorganic substance such as carbon fiber or carbon black into a plastic in order to provide sustainability has been put into practical use, but there is a problem that the color tone is limited to black. On the other hand, recently, a method of imparting a durable antistatic effect by a method using a polymer alloy with a conductive polymer has been disclosed. For example, Japanese Patent Laid-Open No. 61-18555
No. 7, JP-A-62-25164, and JP-A-SHO-6
A method of adding an epihalohydrin-based polymer such as epichlorohydrin rubber is disclosed in JP-A-4-1748, and a method of adding a polyether ester amide is disclosed in JP-A-58-118836. However, these methods have a problem that unless the conductive polymer is added in a large amount to the target plastic, sufficient antistatic properties cannot be exhibited and the mechanical properties of the plastic are deteriorated. As a technique that requires a relatively small amount of addition, Japanese Patent Application Laid-Open No. 48-65237 discloses a method of adding a tertiary amine salt of polystyrenesulfonic acid to a plastic. Although the antistatic property afterwards is maintained to some extent, the effect is not yet sufficient.

[0002]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antistatic agent that exhibits good antistatic properties even when it is added in a small amount, and that has good washing resistance with water.

The present invention provides a salt of a styrene-based polymer sulfonate having a specific weight average molecular weight (or a sharp molecular weight distribution) and a specific organic base. This was done based on the finding that the above problems can be solved by using them. That is, the present invention has a weight average molecular weight of 3,000 to 300,0.
An antistatic agent comprising a sulfonated styrene polymer of No. 00 and a salt of an organic base.

[0003]

TECHNICAL FIELD The antistatic agent of the present invention has a weight average molecular weight of 2,000 to 100,000 (preferably, the molecular weight distribution (Mw / Mn) is 2.0 to 2.0).
8) a styrene polymer sulfonate and an organic base are reacted, or an alkali metal or alkaline earth metal salt of the sulfonate and an organic base having a counter ion which forms an insoluble salt with the metal. It can be produced by ion exchange. The above-mentioned sulfonated styrene polymer or alkali (earth) metal salt has a weight average molecular weight of 1,000 to 50,000 (preferably a molecular weight distribution) according to the method disclosed in Japanese Patent Application No. 6-166633. The styrene-based polymer having a (Mw / Mn) of 2.0 to 2.8) is added to the styrene-based polymer in an amount of 0.1 to 100 parts by weight.
By introducing a sulfonating agent into a halogenated hydrocarbon solvent which is dissolved together with 10 parts by weight of an ether compound and / or a carbonyl group-containing compound and reacting the styrenic polymer with the sulfonating agent, alkali metal or It can be produced by neutralizing with an alkaline earth metal hydroxide. The disclosure of Japanese Patent Application No. 6-166633 is included in the present specification.

As the styrene polymer used here, not only polystyrene but also poly-α-methylstyrene,
A styrene-α-methylstyrene copolymer, a styrene acrylic copolymer, or the like can be used. If the molecular weight of the antistatic agent of the present invention is less than 3,000, the water resistance of the antistatic agent decreases, and if it is more than 300,000, the viscosity becomes high and the antistatic effect is difficult to be exhibited at a low addition amount. Become. Furthermore, the workability and the yield at the time of manufacturing the antistatic agent itself are reduced. The molecular weight is preferably 4,000 to 250,000, more preferably 5,000 to 200,000.
0.

The sulfonation rate of the styrene polymer which is the antistatic agent of the present invention is preferably 30% or more. The sulfonation rate is preferably 40% to 100%, particularly preferably 50 to 95%. In the antistatic agent of the present invention, it is desirable that 70% to 100% of the sulfone groups in the polymer form a salt with an organic base. In the antistatic agent of the present invention, various organic bases can be used as the organic base that forms a salt with the sulfonated styrene polymer, but a tertiary amine having a hydrocarbon group having 6 or more carbon atoms is used. Preferably, more preferably the third compound represented by the general formula (I)
Examples include primary amines.

[0006]

Embedded image R ₁ N (R ₂ ) R ₃ (I) (wherein R ₁ , R ₂ and R ₃ are the same or different saturated or unsaturated hydrocarbon groups, and R ₁ , R ₂ And at least one of R ₃ is a hydrocarbon group having a carbon number of 6 or more, and R ₁ and R ₂ may be connected to each other to form a heterocycle with a nitrogen atom, and in this case, R ₁ and At least one of the groups to which R ₂ is linked or R ₃ is a hydrocarbon group having 6 or more carbon atoms.) The saturated or unsaturated hydrocarbon group represented by R ₁ , R ₂ and R ₃ has 1 to 1 carbon atoms. 22 alkyl groups, alkenyl groups, phenyl groups, substituted phenyl groups, aralkyl groups, cycloalkyl groups and the like. The saturated or unsaturated hydrocarbon group having a substituent introduced therein has 1 to 22 carbon atoms.
The N-acylaminoalkyl group, the acyloxyalkyl group, the hydroxyalkyl group, the group in which an alkylene oxide is added to the hydroxyalkyl group, and the like can be mentioned.
It is essential that at least one of R ₁ , R ₂ and R ₃ is a hydrocarbon group having 6 or more carbon atoms, and one having 8 to 22 carbon atoms is preferable. Further, a quaternary ammonium salt having a hydrocarbon group having 6 or more carbon atoms is also preferable, and among these, the quaternary ammonium salt represented by the general formula (II) is preferable.

[0007]

[Image Omitted] R ₄ N ⁺ (R ₅ ) (R ₆ ) R ₇ · X ⁻

[0008] _{(wherein, R 4, R 5, R} 6 and R ₇ are each a hydrocarbon group or substituted hydrocarbon group, saturated or unsaturated identical or _{different, R 4, R 5, R} 6 and R
_At least one of ₇ contains a hydrocarbon group having 6 or more carbon atoms. R ₄ and R ₅ may be linked to each other to form a heterocycle together with a nitrogen atom. In this case, a group in which R ₄ and R ₅ are linked or at least one of R ₆ and R ₇ has 6 or more carbon atoms. Is a hydrocarbon group. X is a halogen atom, NO ₃ , 1
It is an anion such as / 2 (SO ₄ ). ). R ₄ , R ₅ , R
₆ and R ₇ are unsubstituted or substituted saturated or unsaturated hydrocarbon groups. Examples of the unsubstituted hydrocarbon group include an alkyl group having 1 to 22 carbon atoms, an alkenyl group, a phenyl group and a cycloalkyl group. As the hydrocarbon group having a substituent introduced, an alkylene oxide is added to a substituted phenyl group having 1 to 22 carbon atoms, an aralkyl group, an N-acylaminoalkyl group, an acyloxyalkyl group, a hydroxyalkyl group or a hydroxyalkyl group. Groups and the like.

It is essential that at least one of R ₄ , R ₅ , R ₆ and R ₇ is a hydrocarbon group having 6 or more carbon atoms, and one having 8 to 22 carbon atoms is particularly preferable. The carbon number of the remaining three hydrocarbon groups is not particularly limited. The antistatic agent of the present invention can be applied to a wide variety of plastics to exhibit antistatic properties. Examples of plastics include polyethylene resin, polypropylene resin, acrylic resin, polystyrene resin, polyacrylonitrile resin, AS resin, MS resin, vinyl chloride resin, ABS resin, polyethylene terephthalate, polyamide, polycarbonate resin, and polyphenylene ether resin. You can The antistatic agent of the present invention is 0.1 to 15 parts by weight, preferably 100 parts by weight of the above plastic.
It is suitable to add 0.3 to 12 parts by weight, particularly preferably 0.5 to 10 parts by weight.

When the antistatic agent of the present invention is added to various plastics, lubricants such as higher alcohols, fatty acid amides and fatty acid metal soaps, antioxidants, ultraviolet absorbers, silicon derivatives, antiblocking agents are added as required. , A colorant, a filler, and other additives can be used in combination. When the antistatic agent of the present invention is added to plastic, the antistatic agent in the form of powder, wax or paste is uniformly mixed with pellets or powdery plastic in a Henschel mixer or extruded once. After the compound containing the antistatic agent is prepared by a machine, the compound can be supplied to various molding machines for processing. It is also possible to process the masterbatch containing the antistatic agent in a high concentration and dilute the masterbatch for use. The plastics to which the antistatic agent of the present invention has been added are subjected to press molding, injection molding, extrusion molding, blow molding, calender molding, etc. in the same manner as unadded plastics to form sheet films and various shaped articles. You can

[0011]

INDUSTRIAL APPLICABILITY The antistatic agent of the present invention, when kneaded into various plastics, exhibits an antistatic effect extremely quickly, maintains the effect in a wide temperature and humidity range for a long time, and is washed with water. It has excellent properties. Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

【Example】

Production Example 1 100 parts by weight of polystyrene having a weight average molecular weight of 5000 (Mw / Mn = 2.1) was dissolved in 400 parts by weight of 1,2-dichloroethane, and 1.0 part by weight of acetone was further added to prepare a raw material solution. . This raw material solution was continuously supplied to a sulfonation reactor equipped with a turbine-type stirrer together with SO ₃ , which is a sulfonating agent, to perform a sulfonation reaction at 45 ° C.
In this case, the feed rate is 23.6 g / min of raw material and SO ₃ 4.
0 g / min, SO ₃ / polystyrene molar ratio is 1.10
Also, the reactor is equipped with a jacket and the tank capacity is 400 m.
1 was used. 1 part of the obtained sulfonated product
After neutralization with 0% NaOH, separation was carried out to obtain Na polystyrene sulfonate. The obtained polystyrene sulfonate Na had a weight average molecular weight of 9200, Mw / Mn of 2.2,
The sulfonation rate was 88%.

10% of this polystyrene sulfonate Na
The aqueous solution and an IPA solution of octadecyltrimethylammonium chloride were mixed with stirring, then filtered and washed with water to obtain octadecyltrimethylammonium salt of polystyrenesulfonic acid (antistatic agent A). The octadecyltrimethylammonium chloride and the sulfone group in Na polystyrene sulfonate were reacted in equimolar amounts. The molecular weight of the antistatic agent A is 24,000, Mw / M
It was n = 2.2. Then, for the remaining sulfonates,
Octadecyldimethylamine in the same amount as the number of moles of sulfone groups in the sulfonated product was added and reacted to synthesize an octadecyldimethylamine salt of polystyrenesulfonic acid (antistatic agent B). The molecular weight of the antistatic agent B is 2300
0 and Mw / Mn = 2.2.

Production Example 2 100 parts by weight of polystyrene having a weight average molecular weight of 9000 (Mw / Mn = 2.1) was dissolved in 400 parts by weight of 1,2-dichloroethane, and 5.0 parts by weight of benzoic acid was further added to prepare a raw material. A solution was prepared. This raw material solution was subjected to a sulfonation reaction at 55 ° C. in the same manner as in Reference Example 1, a part of the obtained sulfonated product was neutralized with 10% NaOH, and then separated to obtain Na polystyrene sulfonate. The weight average molecular weight of the obtained polystyrene sulfonate Na was 20,500 and Mw /
Mn was 2.8 and the sulfonation rate was 92%. Using this polystyrene sulfonate Na, a octadecyl trimethyl ammonium salt of polystyrene sulfonate (antistatic agent C) was obtained in the same manner as in Production Example 1. Antistatic agent C
Had a molecular weight of 56000 and Mw / Mn = 2.8. Using the remaining sulfonated product, an octadecyldimethylamine salt of polystyrenesulfonic acid (antistatic agent D) was synthesized in the same manner as in Production Example 1. The molecular weight of the antistatic agent D was 53,000 and Mw / Mn = 2.8.

Production Example 3 Polystyrene having a weight average molecular weight of 5000 (Mw / Mn = 2.1) was used, and acetone was not used. In the same manner as in Production Example 1, Na polystyrene sulfonate and a sulfonated product of polystyrene were obtained. It was The weight average molecular weight of the obtained polystyrene sulfonate Na was 15400, Mw /
Mn was 3.5 and the sulfonation rate was 89%. Using this polystyrene sulfonate Na, the octadecyl trimethyl ammonium salt of polystyrene sulfonate (antistatic agent E) was synthesized in the same manner as in Production Example 1. The molecular weight of the antistatic agent E was 41,000 and Mw / Mn = 3.6. Further, octadecyldimethylamine salt of polystyrene sulfonic acid (antistatic agent F) was synthesized in the same manner as in Production Example 1 using the remaining sulfonated compound. Antistatic agent F
Had a molecular weight of 39000 and Mw / Mn = 3.7.

The properties of the polystyrene sulfonate prepared in the above Production Example were determined as follows. (1) Molecular weight of polystyrene Standard polystyrene is used as a standard substance, and Tosoh Corporation's TSKG1000HXL (7.8 mm ID ×
30cm), UV detector (wavelength 266nm)
And determined by GPC. When styrene was detected in the sample, styrene was excluded and the weight average molecular weight was determined. (2) Molecular Weight of Sulfonated Styrene Polymer Standard sodium standard polystyrene sulfonate was used as a standard substance, and TSK G manufactured by Tosoh Corporation as a separation column.
3000SW (7.5mm ID x 30cm) and TSK G
It was measured by GPC method using 4000 SW (7.5 mm ID × 30 cm) and an ultraviolet ray detector (measurement wavelength 238 nm). When a styrene sulfonate was detected in the sample, the weight average molecular weight and the number average molecular weight were determined, excluding the styrene sulfonate. The molecular weight distribution is the weight average molecular weight (Mw) /
The number average molecular weight (Mn) was calculated and determined.

(3) Sulfonation rate Total S and C were obtained by elemental analysis and calculated by the following equation. (4) Molecular Weight of Tertiary Amine Salt and Quaternary Ammonium Salt of Sulfonated Styrene Polymer As a standard substance, octadecyltrimethylammonium salt of standard polystyrene sulfonate synthesized from standard sodium sodium polystyrenesulfonate and octadecyltrimethylammonium chloride Using TSK G1000HXL (7.8 mm ID) manufactured by Tosoh Corporation as a separation column.
X 30 cm) and an ultraviolet detector (measurement wavelength 26
6 nm) and determined by the GPC method. The molecular weight of the octadecyldimethylamine salt of polystyrene sulfonic acid is the numerical value in terms of the standard substance. The molecular weight distribution is the weight average molecular weight (Mw) at the main peak.
/ The number average molecular weight (Mn) was calculated and calculated.

Example 1 Polypropylene homopolymer 9 with melt flow rate 9
0% and 10% of each of the antistatic agents A to D prepared in Production Examples 1 and 2 were mixed using a Henschel mixer and then kneaded using a twin-screw extruder to prepare strand cut pellets. Next, the pellets were molded into a 76 mm × 76 mm × 1.6 mm plate-shaped sample at a cylinder temperature of 230 ° C. using a TS-150 type injection molding machine manufactured by Nissei Plastic Industry Co., Ltd. This sample is 20 ° C, relative humidity 60
% Of the sample was stored in a thermostatic chamber for 1 day, and then the surface resistivity of the sample was measured. Next, this sample was placed in a beaker and flushed with tap water for 1 hour. Then, the surface moisture was wiped off with gauze and stored in a thermostatic chamber at 20 ° C. and 60% relative humidity for 1 day, and then the surface resistivity of the sample was measured. The results are shown in Table 1. The surface resistivity was measured using a Hiresta H-210 type resistance measuring device manufactured by Mitsubishi Petrochemical Co., Ltd. at a printing voltage of 500V. The antistatic agents E and F prepared in Production Example 3 were used, and a plate-shaped sample was prepared in the same manner as above, and then the same evaluation was performed.
Table 1 shows the measurement results.

[0018]

[Table 1] Table-1 (Evaluation result of antistatic performance for polypropylene) ────────────────────────────────── No. Antistatic agent Surface resistivity (Ω) type Mw / Mn Before washing After washing With water Present invention 1 Antistatic agent A 2.2 8 × 10 ¹¹ 9 × 10 ¹¹ Present invention 2 Antistatic agent B 2.2 6 × 10 ¹¹ 7 × 10 ¹¹ Invention 3 Antistatic Agent C 2.8 5 × 10 ¹¹ 7 × 10 ¹¹ Invention 4 Antistatic Agent D 2.8 7 × 10 ¹¹ 9 × 10 ¹¹ Invention 5 Antistatic Agent E 3 .6 9 × 10 ¹¹ 2 × 10 ¹² Invention 6 Antistatic agent F 3.7 1 × 10 ¹² 3 × 10 ¹² Comparative example No additive-> 2 × 10 ¹⁴ > 2 × 10 ¹⁴

Example 2 90% of an acrylic resin having a melt flow rate of 2 and 10% of each of the antistatic agents A to D prepared in Production Examples 1 and 2
And were mixed using a Henschel mixer, and then kneaded using a twin-screw extruder to prepare strand cut pellets. Next, this pellet is TS manufactured by Nissei Plastic Industry Co., Ltd.
Cylinder temperature 250 ° C using -150 type injection molding machine
Then, it was molded into a plate sample of 76 mm × 76 mm × 1.6 mm. This sample was stored in a thermostatic chamber at 20 ° C. and a relative humidity of 60% for 1 day, and then the resistivity of the sample was measured. Next, after putting this sample in a beaker and running tap water for 1 hour, the surface water was wiped off with gauze, and the sample was placed in a thermostatic chamber at 20 ° C and 60% relative humidity for 1 hour.
After storage for a day, the surface resistivity of the sample was measured. Table-Results
It is shown in FIG. Further, the degree of change in white turbidity of the sample before and after immersion in water was visually compared and evaluated according to the following criteria. No change: ◎ Very slightly turbid: ○ Slightly turbid: △ Quite turbid: × Also, using the antistatic agents E and F prepared in Production Example 3, a plate-shaped sample was prepared in exactly the same manner as above. After the preparation, the same evaluation was performed. Table 2 shows the measurement results.

[0020]

[Table 2] Table-2 (Evaluation result for acrylic resin) ──────────────────────────────────── No Antistatic agent Surface resistivity (Ω) Kind after washing Mw / Mn Before washing After washing White turbidity Present invention 7 A 2.2 6 × 10 ¹¹ 8 × 10 ¹¹ ○ Present invention 8 B 2.2 5 × 10 ¹¹ 7 × 10 ¹¹ ○ Invention 9 C 2.8 6 × 10 ¹¹ 8 × 10 ¹¹ ○ Invention 10 D 2.8 7 × 10 ¹¹ 9 × 10 ¹¹ ○ Invention 11 E 3.6 9 × 10 ¹¹ 3 × 10 ¹² △ Present invention 12 F 3.7 8 × 10 ¹¹ 2 × 10 ¹² △ Comparative example No additive-> 2 × 10 ¹⁴ > 2 × 10 ¹⁴ ◎

Claims (3)

[Claims] 1. A weight average molecular weight of 3,000 to 300,0.
An antistatic agent containing the sulfonated styrene polymer of No. 00 and a salt of an organic base. 2. The antistatic agent according to claim 1, wherein the organic base is a tertiary amine and / or a quaternary ammonium salt having a hydrocarbon group having 6 or more carbon atoms. 3. A molecular weight distribution (Mw /
The Mn) is 2.0 to 2.8, and the antistatic agent according to claim 1.