JPH0770556A - Coatable antistatic agent composition - Google Patents

Abstract

PURPOSE:To obtain a coatable antistatic agent composition which is excellent in antistatic properties and also in antifoaming properties, applicability, heat resistance and long-term storage stability. CONSTITUTION:The composition is prepared by mixing a polyoxyalkylene alkyl ether sulfate with a 1-6C alcohol in a weight ratio of 1:50 to 2:1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating type antistatic agent composition which is coated on the surface of a polymer material to exhibit antistatic ability.

[0002]

2. Description of the Related Art Since synthetic polymers have excellent properties, their applications in various fields have been actively developed. However, one of the drawbacks of synthetic polymers is that they are easily charged. In the past, problems caused by electrostatic charging of synthetic polymers were generally caused by the adsorption of dust or dirt or the discomfort caused by static electricity.
In the field of electronics represented by computer, OA equipment, etc., problems such as noise caused by static electricity and damage to IC parts have been taken up.

In recent years, many countermeasures have been taken against such damage due to static electricity, but among them, the method using an antistatic agent is the best in terms of sustainability of the effect and workability, Widely adopted. This antistatic agent falls into the category of surfactants and is classified into cationic, anionic, nonionic and amphoteric from the viewpoint of ionicity, and these are used alone or in combination.

Cationic antistatic agents include tetraalkylammonium salts and trialkylbenzylammonium salts, and anionic antistatic agents include alkyl sulfonates, alkylbenzene sulfonates, alkyl sulfates, and alkyl phosphorus salts. Examples of the nonionic antistatic agent include acid salts such as polyoxyalkylene alkylamines, glycerin fatty acid esters, and polyoxyalkylene aliphatic alcohols.
Ruether, polyoxyalkylene alkyl phenyl ether and the like, and amphoteric antistatic agents include alkyl betaine and imidazoline.

[0005] These improve the ionic conductivity due to adsorbed water due to the water absorption and water retention properties of the surfactant, and exhibit antistatic ability. Such antistatic agents include a kneading type antistatic agent which is kneaded in advance with a polymer material and transfers a part thereof to the surface to exhibit an antistatic ability, and a kneading type antistatic agent which is applied to the surface of the polymer material and charged. There is a coating type antistatic agent that exhibits antistatic ability, and each of them exhibits conductivity by forming a thin film on the surface of a polymer material.

In the case of a kneading type antistatic agent, the antistatic ability is greatly affected by the compatibility between the antistatic agent and the polymer material, the interaction between the antistatic agent and other additives, and the like. Since the antistatic agent may deteriorate the physical properties and moldability of the polymer material, selection of the antistatic agent is quite difficult. On the other hand, the coating type antistatic agent is more versatile because it can be used regardless of the type of polymer material.

[0007]

As the surfactants used in the coating type antistatic agent, there are many cationic surfactants and amphoteric surfactants from the viewpoint of antistatic ability. In terms of heat resistance, the agent is considerably inferior to the anionic surfactant and the nonionic surfactant. In particular, it can be said that the cationic surfactant is often used as a coating type antistatic agent because it has a drawback that it is inferior in heat resistance.

However, in recent years, for the purpose of improving productivity, drying after coating is often carried out at a high temperature, and anionic antistatic agents having excellent heat resistance tend to attract attention. . Further, most of the cationic surfactants contain chlorine, and hydrogen chloride gas is generated during high temperature drying, which causes a problem of corrosion of equipment and the like.

Under these circumstances, the use of anionic surfactants as coating type antistatic agents has recently been investigated. Anionic surfactants that are often used as antistatic agents include alkyl phosphates, alkylbenzene sulfonates, and alkyl sulfonates, but these have poor wettability with polymer materials and are uniform. However, it is not optimal as a coating type antistatic agent.

Further, the coating type antistatic agent is usually used at a dilute concentration, for example, a concentration of about 1 to 2% by weight at the time of coating, but in the case of an aqueous solution type antistatic agent, this concentration is the most. Foaming tends to occur, and the antistatic agent solution tank foams during the coating operation, resulting in reduced workability. Further, the bubbles cause uneven coating when the object to be processed is dried at a high temperature, deteriorate the appearance, and reduce the antistatic ability. In addition, the surfactant has poor storage stability over time in an aqueous solution having a dilute concentration as described above, and greatly impairs the antistatic ability.

In view of the above circumstances, the present invention has excellent coating properties such that the coating liquid is unlikely to foam, has good wettability to a polymer material, and gives a good appearance after coating and drying. At the same time, it is an object of the present invention to provide a coating type antistatic composition which is excellent in original antistatic ability, heat resistance and storage stability over time.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, by using a specific anionic surfactant and a lower alcohol in a specific ratio, In order to complete the present invention, it was found that a coating type antistatic agent composition having excellent antistatic ability, excellent foaming suppression property and coating property, and also excellent heat resistance and storage stability over time can be obtained. It arrived.

According to the present invention, a) a polyoxyalkylene alkyl ether sulfate and b) an alcohol having 1 to 6 carbon atoms are contained in a weight ratio of a component: b component of 1:50 to 2: 1. The present invention relates to a coating type antistatic agent composition, characterized in that it is contained in the following ratio.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Structure / Function of the Invention The component a polyoxyalkylene alkyl ether sulfate used in the present invention has the following general formula (I): RO (AO) _n SO ₃ M (I) (wherein R is Is an alkyl group, AO is an oxyalkylene group,
M is a counter ion), and the oxyalkylene group (AO) includes an oxyethylene group, an oxypropylene group, an oxybutylene group, etc., and these groups are mixed and contained. May be. A particularly preferred group is the oxyethylene group.

The number of added moles (n) of such an oxyalkylene group is 1 to 50, preferably 4 to 30. If the oxyalkylene group is not added, the water retention capacity of the surfactant will be poor and the antistatic property will be insufficient. Conversely, if the added mole number exceeds 50, the water absorption of the surfactant will be strong and The resulting film becomes cloudy and loses transparency or becomes sticky.

The alkyl group (R) preferably has a chain length of 6 to 18 carbon atoms. When the number of carbon atoms is less than 6, the hydrophilicity of the surfactant becomes too strong and the wettability of the surface of the polymer material deteriorates, resulting in poor performance. On the other hand, when it is larger than 18, it becomes difficult to dissolve in water, and insoluble matter remains on the surface of the polymer material, impairing the appearance of the material. The alkyl group may be an alkylphenyl group such as a nonylphenyl group or an octylphenyl group.

Examples of the counter ion (M) include alkali metals and alkaline earth metals, and sodium and potassium are particularly preferable. When the polyoxyalkylene alkyl ether sulfate is used as an aqueous solution as a coating type antistatic agent, the pH of the solution is adjusted to 4 to 9.5 by selecting this counter ion and using a pH adjusting agent if necessary. It is preferable to adjust so as to achieve storage stability over time.

The alcohol as the component b used in the present invention is a lower alcohol having 1 to 6 carbon atoms, which includes methanol,
Ethanol, n-propanol, isopropanol and the like are preferably used. These contribute to suppressing foaming of the aqueous solution and improving storage stability over time. 6 carbon atoms
Alcohols over 10% do not dissolve easily in water, resulting in poor coatability, poor appearance after coating, and loss of antistatic ability, and also for improving foam control and storage stability over time. I can't get good results.

In the present invention, the ratio of the polyoxyalkylene alkyl ether sulphate as the component a and the alcohol as the component b is such that the weight ratio of the former to the latter is 1:50 to 2: 2.
A ratio of 1 is preferable, and a ratio of 1:50 to 2: 3 is particularly preferable. If the amount of component a used is less than the above, the antistatic effect will be insufficient, and a large amount of alcohol will volatilize in the air during drying after coating, which is a safety and work environment problem. Become. On the contrary, when the amount of the component a used is larger than the above amount, the foaming suppressing property is deteriorated and the storage stability with time is deteriorated.

The coating type antistatic composition of the present invention comprises a polyoxyalkylene alkyl ether sulfate of component a and b.
Alcohol of the component, the concentration of a component in water is usually 1 to 3
As a coating liquid dissolved in water so as to be about wt%,
Be used. At that time, known additives may be appropriately contained in the coating liquid. By applying this coating solution to the surface of a polymer material in the form of a film or the like by a dipping method or the like and drying it, good antistatic ability can be imparted to the material.

[0021]

EFFECT OF THE INVENTION The coating type antistatic agent composition of the present invention has excellent coating properties such that the coating liquid is unlikely to foam, has good wettability to polymer materials, and gives a good appearance after coating and drying. In addition, it has the advantage of being excellent in original antistatic ability, heat resistance and storage stability over time.

[0022]

EXAMPLES Next, examples of the present invention will be described to more specifically describe.

Example 1 Sodium polyoxyethylene dodecyl ether sulfate as component a (in the above general formula (I), AO = oxyethylene group, n = 4, R = dodecyl group, M = sodium)
, Ethanol was used as the b component, the weight ratio of the a component: b component was 1: 2, and these were dissolved in water so that the concentration of the a component in water was 2% by weight, and the coating type An antistatic agent aqueous solution was prepared.

Example 2 As component a, sodium polyoxyethylene dodecyl ether sulfate [in the above general formula (I), AO = oxyethylene group, n = 1, R = dodecyl group, M = sodium]
A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except that

Example 3 Sodium polyoxyethylene dodecyl ether sulfate [AO = oxyethylene group, n = 50, R = dodecyl group, M = sodium in the above general formula (I)] was used as the component a. A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except for the above.

Example 4 Sodium polyoxyethylenehexyl ether sulfate as component a (AO = oxyethylene group, n = 4, R = hexyl group, M = sodium in the above general formula (I))
A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except that

Example 5 As component a, sodium polyoxyethylene stearyl ether sulfate [AO = oxyethylene group, n = 4, R = stearyl group, M = sodium in the above general formula (I)] was used. A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except for the above.

Example 6 As component a, sodium polyoxyethylene octylphenyl ether sulfate [in the above general formula (I), AO =
Oxyethylene group, n = 4, R = octylphenyl group,
M = sodium], and otherwise the same as in Example 1 to prepare a coating type antistatic agent aqueous solution.

Example 7 A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except that methanol was used as the component b.

Example 8 Hexanol was used as the component b, and the other components were used in Example 1.
A coating type antistatic agent aqueous solution was prepared in exactly the same manner as in.

Example 9 Except that the weight ratio of component a: component b was changed to 1:50,
A coating type antistatic agent aqueous solution was prepared in exactly the same manner as in Example 1.

Example 10 A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except that the weight ratio of the component a: the component b was changed to 2: 1.

Comparative Example 1 Coating was carried out in the same manner as in Example 1 except that dodecyltrimethylammonium chloride (cationic surfactant) was used in place of the component a sodium polyoxyethylene dodecyl ether sulfate. An aqueous antistatic agent solution was prepared.

Comparative Example 2 Example 1 was repeated except that sodium dodecylbenzenesulfonate (anionic surfactant) was used in place of the component a sodium polyoxyethylene dodecyl ether sulfate.
A coating type antistatic agent aqueous solution was prepared in exactly the same manner as in.

Comparative Example 3 Instead of sodium polyoxyethylene dodecyl ether sulfate as the component a, sodium dodecyl sulfate [corresponding to n = 0, R = dodecyl group, M = sodium in the above general formula (I)] A coating type antistatic agent aqueous solution was prepared in the same manner as in Example 1 except that

Comparative Example 4 An aqueous solution of a coating type antistatic agent was prepared in the same manner as in Example 1 except that octanole was used in place of ethanol as the component b.

Comparative Example 5 A coating type antistatic aqueous solution was prepared in the same manner as in Example 1 except that the component b was not used.

Comparative Example 6 Except that the weight ratio of component a: component b was changed to 1:70,
A coating type antistatic agent aqueous solution was prepared in exactly the same manner as in Example 1.

Comparative Example 7 A coating type antistatic agent aqueous solution was prepared in exactly the same manner as in Example 1 except that the weight ratio of the component a to the component b was changed to 3: 1.

The above Examples 1 to 10 and Comparative Examples 1 to 7
For each coating type antistatic agent aqueous solution of,
The antistatic ability, foam suppression, coating property, heat resistance and storage stability over time were measured and evaluated. The results are shown in Tables 1 and 2 below.

<Antistatic Ability> A coating type antistatic agent aqueous solution is dip-coated on a commercially available polyethylene terephthalate film, and then the temperature is 20 ° C. and the relative humidity is 50%.
The film was air-dried for 2 hours under a constant temperature and constant humidity environment to prepare an antistatic film. For this treated film, the surface resistivity (Ω) of the film surface was measured using a surface resistivity meter to evaluate the antistatic ability.

<Foam formation inhibitory property> In a graduated cylinder with a stopper of 100 ml, 50 ml of an aqueous solution of a coating type antistatic agent was placed and the stopper was opened. After shaking twice, the stopper was opened and the height of the foam was measured immediately. By doing so, the foam suppressing property was evaluated.

<Coatability> The coatability was evaluated by the two items of wettability and coating appearance. The wettability and the coating appearance are the wettability to the film when the coating type antistatic agent aqueous solution is applied to the film in the production of the antistatic treatment film, and the appearance of the antistatic treatment film prepared by air-drying after coating. It was examined visually (whether or not there was cloudiness due to uneven coating) and evaluated as follows. The coating appearance was not evaluated for those that could not be coated due to poor wettability. § Wetting property ◎… Wet evenly and cleanly ○… Slightly uneven but cleanly wet △… Repels only partially wet ×… Can not be repelled at all § Appearance ◎… Transparent and has no cloudiness ○… The film is slightly hazy, but the transparency is not impaired. △ ... White haze is recognized and the transparency is impaired. × ... White turbidity is observed and the film is not transparent.

<Heat resistance> As a heat resistance test, the antistatic-treated film produced by the above method was left at a temperature of 150 ° C. for 5 minutes, and then the surface resistivity of the film was measured by a surface resistivity meter ( Ω) was measured. This surface specific resistance (Rs) and the surface specific resistance (R
o) was compared and evaluated as follows. ◎… Both are almost the same level ○… Rs rises to about 10 times Ro △… Rs rises to about 100 times Ro ×… Rs rises to about 1,000 times Ro

<Storage stability over time> The storage stability over time was evaluated by the change in surface resistivity and the change in pH. As a storage test, the change in the surface resistivity was carried out by placing the coating type antistatic agent aqueous solution in a container for 4 months and storing it, and then preparing an antistatic treatment film in the same manner as described above. And the surface specific resistance (Ω) was measured. By comparing this surface specific resistance (Rt) with the surface specific resistance (Ro) of the antistatic film produced without the storage test, it is possible to evaluate the degree of attenuation of the antistatic performance after long-term storage. did. In addition, the pH change can be carried out by placing the coating type antistatic agent aqueous solution in an appropriate glass container, covering it with a lid and storing it in a water bath at 60 ° C. for 1 month, 2 months and 4 months. The pH of the aqueous solution was measured.
The storage stability with time was evaluated by comparing the pH after the storage with the initial pH.

[0046]

[Table 1]

[0047]

[Table 2]

As is clear from the results shown in Tables 1 and 2, the coating type antistatic agent aqueous solutions of Examples 1 to 10 of the present invention have good antistatic ability and foam suppressing ability. It has excellent coating properties, heat resistance, and storage stability over time. On the other hand, the aqueous solution of the coating type antistatic agent of Comparative Example 1 in which a cationic surfactant was used instead of the component a was significantly inferior in heat resistance, and an anionic surfactant other than the component a was used. The coating type antistatic agent aqueous solutions of Comparative Examples 2 and 3 are inferior in antistatic ability, and the coating type antistatic agent aqueous solutions of Comparative Example 2 also show a decrease in coating property.

Further, in the coating type antistatic agent aqueous solution of Comparative Example 4 in which octanole having 8 carbon atoms was used in place of the component b,
Since the water solubility of the alcohol itself is reduced, the aqueous solution becomes a viscous suspension, which significantly impairs the coating properties, and in particular the white powder blown on the surface after film drying,
The appearance of the coating becomes extremely poor, and the antistatic ability and stability over time also deteriorate. Furthermore, in the coating type antistatic agent aqueous solution of Comparative Example 5 in which the component b was not used, the foaming was remarkable and the pH of the aqueous solution was significantly decreased with time, and the antistatic ability was completely lost after 4 months.

The weight ratio of the component a to the component b is 1: 7.
In the case of the coating type antistatic agent aqueous solution of Comparative Example 6 which is 0, the sufficient amount of antistatic agent cannot be obtained because the antistatic agent amount is insufficient, and the weight ratio of the component a to the component b is 3: 1. In the coating type antistatic agent aqueous solution of Comparative Example 7, the amount of alcohol is too small, so that the foaming suppressing property is lowered, the coating property is deteriorated, and the storage stability with time is lowered.

The anionic surfactant used in Comparative Example 3 is a surfactant in which the number of moles of oxyalkylene groups added in the general formula (I) is 0. It is presumed that the antistatic ability of the agent is not sufficient because its water retention capacity is not strong. On the other hand, sodium polyoxyethylene dodecyl ether sulfate [AO = oxyethylene group, n = 60, R = dodecyl group, M = sodium in the above general formula (I)] is used as the component a, and the others are carried out. From another test example using a coating type antistatic agent aqueous solution prepared in exactly the same manner as in Example 1, the general formula (I)
In the case of using a surfactant in which the number of moles of oxyalkylene groups added exceeds 50, the amount of water adsorbed becomes too large, which causes the film to become sticky or whiten and impair the appearance. It was recognized that there was a tendency to come.

As the component a, sodium polyoxyethylene butyl ether sulfate [the above-mentioned general formula (I)
AO = oxyethylene group, n = 4, R = butyl group,
M = sodium] and the other tests were carried out in the same manner as in Example 1 except that the coating type antistatic agent aqueous solution was prepared. From the general formula (I), the number of carbon atoms of the alkyl group was smaller than 6. It was found that when such a surfactant is used, the hydrophilicity becomes too strong, the wettability of the aqueous solution on the film surface is lowered, and sufficient antistatic ability cannot be obtained.

Further, as the component a, sodium polyoxyethylene araquinyl ether sulfate [in the above general formula (I), AO = oxyethylene group, n = 4, R = araquinyl group, M = sodium] is used. , Others are Example 1
From another test example using a coating type antistatic agent aqueous solution prepared in exactly the same manner as above, in the general formula (I), when a surfactant having an alkyl group having a carbon number of more than 18 is used,
It was also confirmed that the solubility in water was lowered, and the insoluble matter remained on the film surface after coating and drying, impairing the surface appearance, and that sufficient antistatic ability could not be obtained.

Claims (1)

[Claims] 1. A) polyoxyalkylene alkyl ether
Tellurium sulfate and b) an alcohol having 1 to 6 carbon atoms,
A coating type antistatic agent composition comprising a component: b component in a weight ratio of 1:50 to 2: 1.