JPH0529670B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is a low-humidity dependent material that is not affected by atmospheric humidity, has a stable surface resistivity value at a low level, and has a very short charge decay time. This invention relates to antistatic agents. [Prior Art] In recent years, various problems caused by static electricity have become a problem, and countermeasures have been taken in various fields. For example, measures to prevent static electricity in semiconductor electronic equipment include printing plastic films for packaging, mixing plastic molded products into paints, and in the case of plastic food containers, measures against static electricity damage such as dust adhesion have been taken. Generally, commercially available antistatic agents are all in the category of surfactants, and are used either as combinations of cationic, anionic, nonionic, or amphoteric ionic types, or as single agents. Due to their excellent water absorption and water retention properties, which are the characteristics of surfactants, they are used to enhance ionic conductivity due to adsorbed water and have antistatic properties. [Problems with the Prior Art] By the way, in the surfactant molecule used as a coating type antistatic agent, the hydrophilic group in the molecular structure plays a particularly important role. The water absorption, hygroscopicity, water retention, and moisturizing properties of the hydrophilic groups represented by the four ionic types mentioned above are major factors that determine the ionic conductivity (surface resistance value) of antistatic agents, and prevent static electricity when exposed to the atmosphere. The surface resistance value of the surface largely depends on the relative humidity in the atmosphere. In other words, most surfactants exhibit a resistance value of 10 ¹⁰ Ω/□ or lower in an environment with humidity of 50% or higher, but a resistance value of 10 ¹⁰ Ω/□ under conditions of 20% or lower.
The current situation is that the amount increases to such an extent that it is no longer able to fulfill its role as an antistatic agent. In the recent manufacturing of advanced electronic products, a surface resistance value of 10 ⁹ Ω/□ or more is required under a humidity of 12% to 15% RH. In addition, conventional coating type antistatic agents have high hygroscopicity at high humidity, which also causes stickiness on the coated surface. Therefore, if the performance required for a coating type antistatic agent is listed, it must have the following items. (1) 10 ⁹ Ω/□ or less at low humidity (20% RH or less). (2) No stickiness on the surface at high humidity (60% RH or higher). (3) Good heat resistance. (4) Good wear resistance. (5) Low toxicity. The purpose of the present invention is to propose an antistatic agent that has low hygroscopicity under high humidity conditions and does not lose its moisturizing properties under low humidity conditions. [Means for Solving the Problems] In order to solve the above problems, the present invention proposes the following antistatic agent. (1) A low-humidity-dependent antistatic agent made by blending a small amount of diethanolamide, a linear fatty acid, with the fatty acid ertel of choline chloride. (2) A low humidity-dependent antistatic agent made by blending a small amount of linear fatty alkyl diethanolamine with a fatty acid ester of choline chloride. (3) A low humidity-dependent antistatic agent comprising a fatty acid ester of choline chloride mixed with a small amount of linear fatty acid diethanolamide and linear fatty alkyl diethanolamine. (4) A low humidity-dependent antistatic agent comprising the above (1), (2), and (3) in combination with other surfactants (including nonionic, cationic, and zwitterionic types). To explain the configuration of the present invention in more detail, R ₁ COOCH ₂ CH ₂ N+(CH ₃ ) ₃ CI− (1) Hereinafter, (1) will be referred to as ST. R ₂ −CON(CH ₂ CH ₂ OH) ₂ …(2) R ₃ −N(CH ₂ CH ₂ OH) ₂ …(3) However, the formula R ₁ is a fatty acid consisting of 11 to 21 carbon atoms (carbonized (including those with double bonds in the hydrogen chain)
represents an alkyl group. R ₂ in formula (2) represents a linear aliphatic alkyl group,
The number of carbon atoms is 11-21. R ₃ in formula (3) represents a linear aliphatic alkyl group,
The number of carbon atoms is 12-22. Formula (2) is a general term for diethanolamides of linear fatty acids. (Hereinafter referred to as amide) Formula (3) is a general term for linear fatty alkyl diethanolamines. (Hereinafter referred to as amine) The surface resistance values of these compounds alone are shown in Table 1.

[Table] Amides and amines were both combined with STC, and the formulations showed lower values than the individual surface resistance values shown in Table 1. Showing this, Table 2
It is as follows.

From [Table], it can be seen that the amides and amines added to STC have a significant mutual effect as a means of reducing the surface resistance value. Furthermore, it was found that a combination of the above three types exhibited an even more additive effect. The values are shown in Table 3 below.

[Table] The above combination formulation has excellent antistatic performance as a coating type antistatic agent, especially under low humidity conditions. Also, in these combinations,
Further, a similar additive effect is also exhibited when the diethanolamine derivative is blended with the above-mentioned amides and amines in which ethylene oxide is added to the ethanol group. However, as the number of moles of ethylene oxide added increases, the stickiness increases, making it less desirable as a coating type. Note that all of the above examples were measured by applying a 1% ethanol solution to a polyester film with a thickness of 0.1 μm. In addition, STC, amides, and amines are all insoluble in water, and STC in particular is insoluble in BTX-based, ketone-based, and ester-based solvents, and alcohol-based (methanol, ethanol, isopropyl alcohol).
has a small amount of solubility in However, the combination formulation shown in Table 3 above exhibits solubility in BTX, ketone, alcohol, and water that can be freely diluted. This makes the compound extremely useful as a coating type antistatic agent. In addition, in the oral toxicity test of the formulations in Table 3 above, LD ₅₀
= A value of 16g/Kg or more. In other words, it has low toxicity. Next, the antistatic performance of the formulations shown in Table 4 was further evaluated as formulations for making water-insoluble STC water-soluble and maintaining a low surface resistance value under low humidity.

[Table] As the alkyl betaine in Table 4, a zwitterionic surfactant having the structural formula of Formula 5 was used. Formula (5) (ALKYL DIMETHYL ETHYL
AMMONIUM ETHOSULFATE) In the formula, R ₄ represents an aliphatic alkyl group. [Effects of the present invention] As can be seen from the above examples, by using STC as the main component and adding the above-mentioned amide-based, amine-based, and betaine-based surfactants, the surface resistance value under low humidity conditions can be improved. It is possible to prepare a very useful coating type antistatic agent that maintains a low resistance value. [Example] Weighed 80 g of STC, 15 g of amide, and 5 g of amine,
Dissolve by heating at 90 to 100°C, and gradually add 100 g of an aqueous ethyl alcohol solution to prepare a completely transparent 50% concentration solution (this is called a concentrated solution). This concentrated solution was further diluted 50 times with ethyl alcohol to prepare a 1% solution to obtain an antistatic agent for practical use. Next, apply this inhibitor to a polyester film (25
bar coat with a 10 micron wire bar on top (micron thickness), then dry to coat the surface of the film with a 0.1 micron wire bar.
A completely transparent film (antistatic film) was formed. This performance table is shown in Figures 1-3.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between relative temperature and surface resistance value in Examples. FIG. 2 is a graph showing heat resistance in Examples. FIG. 3 is a graph showing the abrasion resistance in Examples.

Claims (1)

[Claims] 1. A low humidity-dependent antistatic agent comprising a fatty acid ester of choline chloride mixed with a small amount of diethanolamide of a linear fatty acid. 2. A low-humidity-dependent antistatic agent made by blending a small amount of linear fatty alkyl diethanolamine with a fatty acid ester of choline chloride. 3. A low humidity-dependent antistatic agent comprising a fatty acid ester of choline chloride mixed with a small amount of linear fatty acid diethanolamide and linear fatty alkyl-diethanolamine. 4. A low-humidity-dependent antistatic agent made by combining 1, 2, and 3 above with other surfactants (including nonionic, cationic, and amphoteric ionic types).