JPH0411561B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a conductive film-forming emulsion with excellent durability. With the development of the electronics industry in recent years, semiconductor devices have also rapidly advanced and the use of plastics has progressed, but at the same time, various problems such as destruction of semiconductor devices due to electrostatic charging have become more prominent than ever before, and various problems have arisen. Antistatic agents have been put on the market. Among these antistatic agents, the coating type antistatic agent is generally a conductive paint containing a surfactant, carbon particles, or metal particles.
The use of electrolyte polymers has also been applied to various types of recording paper. However, these antistatic agents and low-resistance processing agents have drawbacks such as lack of durability and the formation of black or opaque coatings. In other words, surfactants form a conductive monomolecular film when applied, but they can volatilize during long-term use, easily come off due to friction, and even be washed out by water or solvents, reducing the conductivity. It has the disadvantage that performance deteriorates or disappears. Furthermore, the conductive paint mentioned above is a composite material in which carbon-based particles and metal-based particles are mixed into a polymer substance, and although it has relatively durable performance, it not only lacks transparency and cannot perform a see-through function. Do not damage the appearance of the material being coated,
It has drawbacks such as not being able to print. Furthermore,
A technology has been proposed to create an emulsion paint by introducing a polymer electrolyte into a polymer substance (see Japanese Patent Publication No. 57-22041), and the coating film produced using this technology has improved transparency and durability. Although this method is improved over the prior art described above, it is still insufficient and cannot be put to practical use. The present invention eliminates these conventional drawbacks and provides a method for producing a conductive film-forming emulsion that is self-crosslinkable or externally crosslinkable and has excellent conductivity, transparency, and durability. That is, the highly durable conductive film-forming emulsion of the present invention comprises an ionic electrolyte monomer having an ethylenically unsaturated group, one or more monomers having both a crosslinkable functional group and an ethylenically unsaturated group, and ethylene. It is obtained by emulsion polymerization of one or more monomers having a sexually unsaturated group and acrylic acid using a cationic emulsifier and a nonionic emulsifier. In the method of the present invention, it is essential to use acrylic acid as a type of polymerization component and to use a cationic emulsifier and a nonionic emulsifier together during polymerization, and if even one of these is missing,
A large amount of agglomerates are generated, and an emulsion with good conductive film-forming properties cannot be obtained. As the ionic electrolyte monomer used in the present invention, any monomer having an anionic or cationic electrolyte group and an ethylenically unsaturated group can be used. Representative examples include sodium styrene sulfonate, methacryloyloxyethyltrimethylammonium chloride, 2-hydroxy, 3-methacryloyloxypropyltrimethylammonium chloride, and sulfonic acid groups, quaternary ammonium groups,
All ethylenically unsaturated monomers with salts such as sulfonium groups, phosphonium groups, etc. can be used. The electrolyte monomer is preferably used in a proportion of 5 to 30% of the total monomers used. If the amount used is less than 5%, the desired conductivity cannot be achieved sufficiently, and if the amount used is less than 30%
Even if the above amount is used, the conductivity reaches an equilibrium and it is not possible to further improve the conductivity. Examples of functional groups capable of crosslinking include N-methylol groups, alkoxymethyl groups, hydroxyl groups, glycidyl groups, and amide groups. Typical monomers that have both a crosslinkable functional group and an ethylenically unsaturated group include N-methylol, alkoxymethyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl acrylate, Dimethylamino-2-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate,
Examples include (meth)acrylamide. An ionic electrolyte monomer having an ethylenically unsaturated group, one or more monomers having both a crosslinkable functional group and an ethylenically unsaturated group, one or more monomers having an ethylenically unsaturated group, and acrylic acid. The polymerized polymer can be self-crosslinked or externally crosslinked, and by crosslinking, a conductive film with excellent durability can be formed. Among ionic electrolyte monomers, those having hydroxyl groups can also be considered as one type of these functional monomers, and are more useful than ionic electrolyte monomers having only ethylenically unsaturated groups. Among functional monomers, polymers polymerized using a monomer having both active hydrogen and an ethylenically unsaturated group and an ionic electrolyte monomer having an ethylenically unsaturated group are polyisocyanate, melamine-formalin-based, and urea-formalin-based. It can be externally crosslinked using a thermosetting initial polymer, etc., and by externally crosslinking, a conductive film with excellent durability can be formed. All polyisocyanates can be used, but water-soluble and water-dispersible polyisocyanates are more useful.
These also include blocked isocyanates (masked isocyanates). Any polymerizable monomer that is mainly used in emulsion polymerization can be used as long as it has an ethylenically unsaturated group, and typical examples include vinyl acetate, styrene, alkyl acrylate, and alkyl methacrylate. , ethylene, propylene, vinyl chloride, acrylonitrile, etc. It goes without saying that a monomer having a functional group capable of crosslinking reaction and an ethylenically unsaturated group can also be used as the polymerizable monomer. The coated film using the conductive film-forming emulsion obtained by the method of the present invention is produced by copolymerizing the conductivity-imparting substance into the molecular chain of the polymer, and further crosslinking this polymer to form a stronger conductive polymer. It was possible to form a film with excellent durability such as water resistance, alcohol resistance, and abrasion resistance. Next, the present invention will be specifically explained using Examples and Comparative Examples. Example 1 500 parts of water (parts by weight,
), 10 parts of lauryltrimethylammonium chloride, 10 parts of polyoxyethylene nonylphenol ether, 74 parts of 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride (50% aqueous solution), and 8 parts of N-methylolacrylamide, and further styrene 80
27 parts of n-butyl acrylate, 15 parts of a monomer mixture consisting of 8 parts of acrylic acid, 0.6 parts of 2,2'-azobis(2-amidinopropane) hydrochloride
Stir and heat while introducing nitrogen until 80%
Perform initial polymerization for 30 min at °C. Furthermore, while maintaining the liquid temperature at 80°C, 5 parts of a 5% aqueous solution of 2,2'-azobis(2-amidinopropane) hydrochloride and the remaining 100 parts of the mixed monomer were added dropwise over 1 hour and 40 minutes to carry out emulsion polymerization. Ivy. After the addition was completed, stirring was continued for 1 hour at 80° C. and then cooled to room temperature to obtain a conductive film-forming emulsion. The emulsion obtained had no aggregates, a concentration of 24.9%, a viscosity of 76CP,
The pH was 2.7. Example 2 Emulsion polymerization was carried out in the same manner as in Example 1 except that 46 parts of methacryloyloxyethyltrimethylammonium chloride (80% aqueous solution) was used as the ionic electrolyte monomer to obtain a conductive film-forming emulsion. The emulsion obtained had no aggregates at all, a concentration of 25.9%, a viscosity of 85CP, and a pH of 2.8. Example 3 Into the same polymerization tank as in Example 1, 500 parts of water, 10 parts of lauryltrimethylammonium chloride, 10 parts of polyoxyethylene nonylphenol ether, 2
-Add 74 parts of hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, and further add 80 parts of styrene and n-butyl acrylate.
27 parts, 8 parts of 2-hydroxyethyl acrylate,
23 parts of a mixed monomer consisting of 8 parts of acrylic acid,
0.6 part of 2,2'-azobis(2-amidinopropane) hydrochloride was added and emulsion polymerization was carried out in the same manner as in Example 1 to obtain a conductive film-forming emulsion. The emulsion obtained was completely free of aggregates, had a concentration of 24.9%, a viscosity of 49CP, and a pH of 2.6. Comparative Example 1 In a polymerization tank similar to Example 1, 500 parts of water, 8 parts of lauryltrimethylammonium chloride, 8 parts of polyoxyethylene nonylphenol ether, and Chemistat 6300 (a 30% aqueous solution of cationic polymer electrolyte manufactured by Sanyo Chemical Industries, Ltd.) were added. Added 123 parts, further 88 parts of styrene, 27 parts of n-butyl acrylate,
23 parts of a mixed monomer consisting of 8 parts of acrylic acid,
Add 0.23 parts of 2,2'-azobis(2-amidinopropane) hydrochloride, stir and heat while introducing nitrogen, and perform initial polymerization at 80°C for 30 minutes.
While keeping the liquid temperature at 80℃, add 2,2′-azobis(2
-amidinopropane) 5% of hydrochloride
Emulsion polymerization was carried out by dropping 5 parts of the aqueous solution and the remaining 100 parts of the mixed monomer over 1 hour and 40 minutes. After the addition was completed, stirring was continued for 1 hour at 80° C. and then cooled to room temperature to obtain a conductive film-forming emulsion. The emulsion obtained was completely free of aggregates and had a concentration of 22.9
%, viscosity 74CP, and pH 3.3. Comparative Example 2 500 parts of water, 8 parts of lauryltrimethylammonium chloride, 8 parts of polyoxyethylene nonylphenol ether, 123 parts of Chemistat 6300, and 8 parts of N-methylolacrylamide were added to the same polymerization tank as in Example 1, and further 80 parts of styrene. , 27 parts of n-butyl acrylate, 15 parts of a mixed monomer consisting of 8 parts of acrylic acid, and 0.23 parts of 2,2'-azobis(2-amidinopropane) hydrochloride were added, and emulsion polymerization was carried out in the same manner as in Comparative Example 1. A conductive film-forming emulsion was obtained. The emulsion obtained was completely free of aggregates, had a concentration of 22.9%, and a viscosity of
It was 85CP and PH3.4. Comparative Example 3 Emulsion polymerization was carried out in the same manner as in Comparative Example 1, except that 88 parts of styrene, 19 parts of n-butyl acrylate, 8 parts of 2-hydroxyethyl acrylate, and 8 parts of acrylic acid were used as the mixed monomers, and the conductive film forming property was I got an emulsion. The resulting emulsion had no aggregates, a concentration of 22.9%, a viscosity of 120CP, and a pH of 2.5.
It was hot. Comparative Example 4 In the same polymerization tank as in Example 1, 500 parts of water, 10 parts of lauryltrimethylammonium chloride, 10 parts of polyoxyethylene nonylphenol ether, 2
-Add 74 parts of hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, and further add 88 parts of styrene and n-butyl acrylate.
23 of a mixed monomer consisting of 27 parts and 8 parts of acrylic acid.
part, 2,2'-azobis(2-amidinopropane)
Adding 0.23 parts of hydrochloride, the following Comparative Example 1
Emulsion polymerization was carried out in the same manner as above to obtain a conductive film-forming emulsion. The emulsion obtained was completely free of aggregates, had a concentration of 24.9%, a viscosity of 45CP, and a pH of 2.8. Comparative Example 5 Emulsion polymerization was carried out in the same manner as in Comparative Example 4 except that 46 parts of methacryloyloxyethyltrimethylammonium chloride was used as the electrolyte monomer to obtain a conductive film-forming emulsion. The emulsion obtained is completely free of aggregates and has a concentration of 25.9
%, viscosity 46CP, and pH 2.8. Comparative Example 6 A conductive film-forming emulsion was produced under the same conditions as in Example 1 except for the acrylic acid, but the resulting emulsion contained a large amount of aggregates. It was hot. Comparative Example 7 A conductive film-forming emulsion was produced under the same conditions as in Example 1 except for lauryltrimethylammonium chloride, but the obtained emulsion was the same as in Comparative Example 6. It contained a large amount of aggregates. Comparative Example 8 A conductive film-forming emulsion was produced under the same conditions as in Example 1 except for the polyoxyethylene nonyl phenol ether in the formulation of Example 1, but the emulsion obtained was the same as Comparative Example 6.
Similarly, it contained a large amount of aggregates. Comparative Example 9 A conductive film-forming emulsion was produced under the same conditions as in Example 1 except for lauryl trimethyl ammonium chloride and polyoxyethylene nonyl phenol ether in the composition of Example 1. The emulsion contained a large amount of agglomerates. <Tests and Results> The emulsions obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were each diluted to a concentration of 10% (however,
In the case of the emulsions obtained in Example 3 and Comparative Example 3, a water-dispersible polyisocyanate with an NCO% of 20.1% was added with strong stirring to give an index of 110) and coated on a polyester film with a thickness of 80μ. coating (approximately 3μm coating thickness), both
After drying by heating at 80°C for 5 minutes, a conductive film was obtained by heat treatment at 150°C for 5 minutes. The following tests were conducted on the obtained conductive film. The results are shown in the table. (1) Adhesion: Based on a close-up test. (2) Abrasion resistance: Rub 100 times with a nylon cloth and measure appearance and electrical resistance. (3) Hardness: Measure with pencil hardness (using Mitsubishi Uni). (4) Water resistance: Soak in water for 24 hours. Measure the appearance and electrical resistance after immersion (5) Alcohol resistance: Soak in methanol for 24 hours and measure the appearance and electrical resistance after immersion (6) Surface electricity: manufactured by Tokyo Electronics Co., Ltd. STACK Resistance TR -3 was used.Evaluation: ◯: Good, △: Slightly poor ×: Poor The measurement of the electrical resistance value in (6) was carried out under the same conditions after being left in a sealed container with controlled humidity for more than 1 hour. Samples immersed in water and methanol are kept at room temperature.
After being air-dried for 24 hours or more, measurements were made under the same conditions as above.

【table】

[Table] As is clear from Example 1 and Comparative Examples 6 to 9, when a cationic emulsifier and a nonionic emulsifier are used in combination and acrylic acid is not used, an emulsion with good conductive film-forming properties without aggregates can be obtained. is something that cannot be obtained. As is clear from the results shown in the table, the conductive film obtained by the conductive film-forming emulsion obtained by the method of the present invention has excellent transparency and durability. In other words, the conductive film manufactured by the method shown in the comparative example has a large resistance change due to water resistance and alcohol resistance. In addition, it has defects in one or more of transparency, adhesion, abrasion resistance, hardness, water resistance, and alcohol resistance. The conductive film obtained by the conductive film-forming emulsion obtained by the method of the present invention has a high surface resistance value at low humidity, but as shown in the figure, the electrostatic voltage decay rate is a typical characteristic of the antistatic function. but
It fully satisfies the MIL standard (MIL-B-81705B, standard value 2.00 seconds or less) and does not cause any practical problems.

[Brief explanation of drawings]

The figure shows the electrostatic voltage decay rate of a conductive film formed from the highly durable conductive film-forming emulsion obtained according to the present invention.

Claims (1)

[Claims] 1 An ionic electrolyte monomer having an ethylenically unsaturated group, one or more monomers having both a functional group capable of crosslinking and an ethylenically unsaturated group, a monomer having an ethylenically unsaturated group, and acrylic acid are cationically combined. A method for producing a highly durable conductive film-forming emulsion, which comprises emulsion polymerization using an emulsifier and a nonionic emulsifier.