KR100672759B1 - Antistatic coating agents for plastic and method of manufacturing antistatic layer for plastic using the same - Google Patents

Abstract

Provided are an antistatic coating agent, which forms an antistatic layer superior in an antistatic property, adhesion to plastic materials, gloss, scratch resistance, and transparency, and a method for manufacturing an antistatic layer for plastics. The antistatic coating agent comprises 50-70wt% of a modified acrylic resin, 5-10wt% of carboxymethyl cellulose acetate butyrate, 5-10wt% of an additive including a slip agent and a leveling agent, and 20-40wt% of an organic solvent. The method for manufacturing an antistatic layer for plastics comprises the steps of: forming the antistatic coating agent; and spraying the antistatic coating agent onto the surface of plastics to form an antistatic layer for plastics.

Description

Antistatic coating agent for plastics and manufacturing method of antistatic film using the same {Antistatic coating agents for plastic and method of manufacturing antistatic layer for plastic using the same}

The present invention relates to an antistatic coating for plastics and to a method for manufacturing the antistatic film for plastics using the same, and more particularly to the antistatic coating for plastics and the antistatic coating for plastics using the same It relates to a manufacturing method.

In general, plastics are lighter than metals and are characterized by being free of corrosion and free of corrosion. Due to these characteristics, plastics are used not only in automobiles but also in advanced electronic materials. On the other hand, the plastic has a big disadvantage that it is easy to generate static electricity on the surface. As a result, plastics have low productivity during molding, and there is a risk of fire explosion when storing and transporting flammable paints and solvents. In the manufacturing process of semiconductor devices and electronic equipment, circuit defects frequently occur due to the discharge of static electricity. Have problems.

Therefore, in order to solve the above problems, methods for imparting antistatic properties to plastic surfaces have emerged and developments are in progress.

An example of a method of imparting antistatic property to plastics is an internal addition method in which an antistatic agent is added to the inside of the plastic resin before molding the plastic. As the antistatic agent, an antistatic raw material of a surfactant type is usually used. In this case, the compatibility between the antistatic raw material and the plastic is an important factor, and when the compatibility is excellent, the antistatic raw material is well dispersed on the surface of the plastic resin. The antistatic raw material becomes difficult to apply on the plastic surface. On the other hand, if the compatibility is not suitable, the antistatic raw material is implemented on the surface of the plastic, so that no further subsequent painting work is possible or rather, the physical property of the plastic is degraded. Therefore, the internal addition method has a disadvantage of considering the polarity of the plastic, the crystallinity of the molecular structure and the solubility of the plastic and the solvent.

In addition, there is a method of using nanoparticles, such as indium tin oxide (ITO) and antimony tin oxide (ATO). The nanoparticles may form a transparent thin film through vacuum deposition by a sputtering method or by a wet coating method. This method is mainly used in the manufacture of PDP filters or displays, and it has the disadvantage of requiring expensive equipment and advanced coating technology.

As an example of a method of imparting antistatic property to the plastic, Korean Patent Laid-Open Publication No. 1996-0017509 discloses a method of depositing a diamond-like carbon film on a plastic substrate using a radio wave chemical vapor deposition method. However, the method has a disadvantage that it is not easy to use because of the high deposition technology and the use of expensive raw materials.

As another example, Korean Patent Publication No. 1991-0009871 discloses a transparent antistatic coating composition composed of silicon alkoxide, titanium, alkoxide, zirconium oxy compound (hydrate), acetate, distilled water and inorganic acid. Titanium, an alkoxide, and a zirconium oxy compound, which are conductive materials added here, have a high cost and have a disadvantage of poor wettability with a plastic material due to a high content of water.

For example, an acrylic resin having an antistatic property prepared by solution polymerization by including a metal salt coordinating with an acrylate monomer containing a polyalkylene glycol group is a solvent type resin, and a melamine resin as a curing agent to form a solid dry film. Isocyanate resins or epoxy resins should be used. However, since the drying temperature for curing the curing agents is 100 ° C. or more, it is difficult to apply to plastic materials.

In addition, Japanese Patent Application Laid-Open No. 2000-212535 discloses a pressure-sensitive adhesive having antistatic properties by polymerization of an acrylic monomer having a quaternary ammonium salt at its molecular terminal. In the adhesive, since the monomer having quaternary ammonium is directly polymerized, there is no problem of bleed out to the surface, but yellowing may occur in the quaternary ammonium itself.

An object of the present invention for solving the above problems is to provide an antistatic coating for plastics that can form an antistatic film excellent in antistatic properties, adhesion and transparency to the plastic material.

In addition, another object of the present invention to provide a method for producing an antistatic film for plastic using the antistatic coating for the plastic.

Antistatic coating agent for plastics of the present invention for achieving the above object 50 to 70% by weight of the modified acrylic resin, 5 to 10% by weight of carboxymethyl cellulose acetate butyrate resin, 5 to 10% by weight of an additive including a slip agent and a leveling agent And 20 to 40 wt% of an organic solvent.

For example, the modified acrylic resin may be an acrylic resin copolymerized with quaternary ammonium. In addition, the additive comprises 2.5 to 5% by weight of the slip agent and 2.5 to 5% by weight of the leveling agent, the nonvolatile content of the modified acrylic resin is 9 to 15% by weight, the nonvolatile content of the carboxymethyl cellulose acetate butyrate resin is Has a property of 12 to 20% by weight.

Method for producing an antistatic film for plastics using the antistatic coating for plastics of the present invention for achieving the above another object is 50 to 70% by weight of modified acrylic resin, 5 to 10% by weight of carboxymethyl cellulose acetate butyrate resin, slip agent And an antistatic coating agent for plastics containing 5 to 10 wt% of an additive including a leveling agent and 20 to 40 wt% of an organic solvent. Spraying the antistatic coating on the surface of the plastic to form a plastic antistatic film.

Here, the plastic antistatic film is preferably formed to a thickness of 5 to 30㎛.

The antistatic coating agent for plastics having the above-described composition not only has excellent antistatic property and adhesion to plastic materials, but also excellent properties such as gloss, scratch resistance and transparency.

Antistatic Coatings For Plastics

Hereinafter, the antistatic coating agent for plastics of the present invention will be described in detail.

The antistatic coating agent for plastics of the present invention is an additive and an organic solvent including a modified acrylic resin, carboxymethyl cellulose acetate butyrate (CM-CAB) resin, a slip agent and a leveling agent. It includes.

The modified acrylic resin applied to form the antistatic coating agent is a main antistatic resin that absorbs moisture in the air and exhibits an antistatic effect. In addition, the modified acrylic resin serves to improve adhesion, gloss and transparency when applying the coating on the plastic. As an example of the said modified acrylic resin, the acrylic resin which copolymerized the quaternary ammonium whose solid content (non-volatile content) is 9-15 weight% is mentioned.

When the non-volatile content of the modified acrylic resin is less than 9% by weight, it is difficult to form an appropriate coating film while satisfying the painting workability because the content of solids for forming the antistatic film for plastic is relatively small. On the other hand, when the nonvolatile content exceeds 15% by weight, the long-term storage stability of the modified acrylic resin to be formed is poor, resulting in a problem of obtaining the desired antistatic coating agent. Therefore, the nonvolatile content of the modified acrylic resin is preferably 9 to 15% by weight.

When the content of the modified acrylic resin applied to form a coating agent for forming an antistatic film having an antistatic effect with respect to the plastic is less than 50% by weight, a surface resistance value of 10 ¹⁰ Ω / square or more, Even if the content exceeds 70% by weight, the surface resistance value is not lower than 10 ⁷ Ω / square is not preferable. The antistatic coating agent for the plastic preferably contains 50 to 70% by weight of the modified acrylic resin.

The antistatic effect is evaluated through measurement of the surface resistance value, in particular, very good (excellent) at 10 ⁷ to 10 ⁹ Ω / square, very good at 10 ⁹ to 10 ¹⁰ Ω / square, 10 ¹⁰ to 10 ^It is evaluated as good at ¹¹ Ω / square, moderate at 10 ¹¹ to 10 ¹² Ω / square, and poor at 10 ¹² Ω / square.

Accordingly, the modified acrylic resin is preferably adjusted to have a surface resistance value of 10 ⁷ Ω / square to 10 ⁹ Ω / square.

The carboxymethyl cellulose acetate butyrate (CM-CAB) resin applied to form the antistatic coating is applied as a secondary antistatic resin. In addition, the carboxymethyl cellulose acetate butyrate resin serves to maintain excellent scratch resistance and leveling performance without lowering antistatic properties.

The carboxymethyl cellulose acetate butyrate resin has a glass transition temperature of 120 to 150 ° C., a weight average molecular weight of 15,000 to 25,000, an acid value of 50 to 70 mgKOH / g, and a nonvolatile content of 12 to 20 wt%. .

For example, the carboxymethyl cellulose acetate butyrate resin is 35 to 40% by weight of butyl (Buthyl), 1 to 5% by weight of ethyl (Acethyl) is configured, the solvent is ethyl cellosolve (Ethyl cellosolve: E-cell ).

When the acid value of the carboxymethyl cellulose acetate butyrate resin is thus configured is 50 mgKOH / g or less, there is a problem that the stability of the antistatic coating formed. On the other hand, when the acid value exceeds 70mgKOH / g, there is a problem that the water resistance of the antistatic film for plastic formed by the coating agent is weak. Therefore, the acid value of the carboxymethyl cellulose acetate butyrate resin is preferably 50 to 70 mgKOH / g.

In addition, when the non-volatile content of the carboxymethyl cellulose acetate butyrate resin is less than 12% by weight, it is difficult to form a suitable coating film while satisfying the coating workability because the content of solids for forming the antistatic film for plastics is relatively small. On the other hand, when the nonvolatile content exceeds 20% by weight, it is difficult to dissolve the carboxymethyl cellulose acetate butyrate resin to be formed, resulting in a problem of low stability. Therefore, the nonvolatile content of the carboxymethyl cellulose acetate butyrate resin is preferably 12 to 20% by weight.

In addition, the drying properties of the antistatic film formed when the glass transition temperature of the carboxymethyl cellulose acetate butyrate resin is less than 120 ℃ is reduced or the hardness is lowered, if the antistatic film formed when it exceeds 150 ℃ easily broken, such as Caused. Therefore, the glass transition temperature of the carboxymethyl cellulose acetate butyrate resin is preferably 120 to 150 ° C.

If the weight average molecular weight of the carboxymethyl cellulose acetate butyrate resin prepared with these components is less than 15,000, the scratch resistance of the antistatic film formed is inferior, whereas if the molecular weight is more than 25,000, poor stability is caused. Therefore, it is preferable that the weight average molecular weight of the carboxymethyl cellulose acetate butyrate resin in the antistatic coating is in the range of 15,000 to 25,000.

When the content of the carboxymethyl cellulose acetate butyrate resin applied to form the antistatic coating is less than 5% by weight, scratch resistance and leveling performance imparted to the conventional antistatic film for plastics are reduced. On the other hand, if the content exceeds 10% by weight, the antistatic effect on the plastic material is inferior. Therefore, the antistatic coating agent for plastics preferably contains 5 to 10% by weight of the carboxymethyl cellulose acetate butyrate resin.

The additives applied to form the antistatic coating include a leveling agent and a slip agent as needed for the antistatic coating for the plastic. The leveling agent is an additive for improving the flowability of the coating agent so that the surface of the antistatic film is uniform during coating, and the slip agent penetrates to the surface of the antistatic film during or immediately after coating to reduce the friction coefficient of the surface. It is an additive that improves slip performance.

The leveling agent may be used, such as BYK-333 manufactured by BYK, Inc., the slip agent may be used, such as Glide450, manufactured by Tego.

The additive comprising the leveling agent and the slip agent comprises an amount of 5 to 10% by weight in the antistatic coating. For example, the additive may include 2.5 to 5 wt% of the slip agent and 2.5 to 5 wt% of the leveling agent.

In addition, the antistatic coating for the plastic may additionally use additives used in the existing antistatic coating. That is, in general, the use of the additive is not limited because it is added in a very small amount in order to optimize the elements that affect the manufacturability and workability in the coating agent. As an example of the said additive, an antifoamer, a dispersing agent, an acid catalyst, a plasticizer, a coloring agent, etc. are mentioned. Since the amount of use differs depending on the type of the additive, the amount of use and the type of the additive of the present embodiment are not limiting elements of the present invention.

The organic solvent applied to form the antistatic coating should be selected in consideration of the solubility parameter of the resin, the solvent used in the antistatic coating to improve the workability during the spray coating process, the surface of the dry It is preferable to use butyl cellosolve and ethyl cellussolve which are ethylene glycol solvents to form a uniform antistatic film. The organic solvent includes 20 to 40% by weight of the antistatic coating. For example, 3 to 12% by weight of butyl celusolve, and 10 to 35% by weight of ethyl celusolve, and the organic solvent contains butyl celusolve and ethyl cellulsolve in a content ratio of about 1: 3.

In general, organic solvents are alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone, ketones such as methyl amyl ketone, and methyl acetate. Ester solvents such as ethyl acetate, normal propyl acetate, isopropyl acetate, butyl acetate, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, and carbitol acetate.

Manufacturing method of antistatic film for plastic

Hereinafter, a method of manufacturing an antistatic film for plastic using the antistatic coating agent for plastics of the present invention will be described in detail.

First, it has an antistatic effect on the plastic material, 50 to 70% by weight of the modified acrylic resin, 5 to 10% by weight of carboxymethyl cellulose acetate butyrate resin, 5 to 10% by weight of an additive including a slip agent and a leveling agent To form an antistatic coating for plastics, comprising 20 to 40% by weight of an organic solvent.

Specifically, 5 to 10% by weight of carboxymethyl cellulose acetate butyrate resin having 12 to 20% by weight of nonvolatile matter is added to 20 to 40% by weight of organic solvent. Subsequently, 50 to 70% by weight of the modified acrylic resin having a nonvolatile content of 9 to 15% by weight is added and stirred until a uniform solution is obtained.

Subsequently, 2.5 to 5% by weight of the slip agent Glide450 (manufactured by Tego) and 2.5 to 5% by weight of the leveling agent BYK-333 (manufactured by BYK) were mixed on the solution. As a result, an antistatic coating for plastic is formed. In this case, the coating agent and the constituent elements thereof are described in detail in the antistatic coating agent for plastic, and thus the same description is omitted.

Subsequently, the antistatic coating agent is applied to the plastic surface by spray coating to form a plastic antistatic film. Examples of the plastic include ABS (Acrylonitrile Butadiene Styrene) and MPPO (Modified Polyphenylene Oxide). At this time, the plastic antistatic film has a problem that the antistatic effect is lowered when the thickness is less than 5㎛. On the other hand, if the thickness exceeds 30㎛ causes a problem that the coating cost and the painting operation cost increases. Therefore, the plastic antistatic film is preferably formed to a thickness of 5 to 30㎛ on the surface of the plastic.

Thereafter, the coated plastic antistatic film is dried in an oven at about 80 ° C. for 28 to 32 minutes to complete the antistatic film.

Hereinafter, the characteristics of the antistatic coating agent for plastics through specific examples and evaluation examples of the present invention. However, the present invention is not limited to the following examples and evaluation examples.

Example 1

10% by weight of an organic solvent, butylcellulose, 30% by weight of ethyl cellulose, and 5% by weight of carboxymethyl cellulose acetate butyrate (CM-CAB) resin (14% by weight of nonvolatile matter) were added and mixed for 30 minutes. Then, 50% by weight of a modified acrylic resin (10.4% by weight of non-volatile content) was added and stirred, and when the solution became a completely uniform solution, 2.5% by weight of Glide450 (product of Tego) as a slip agent and BYK-333 (by BYK) as a leveling agent Product) 2.5% by weight of an antistatic coating was obtained.

Example 2

7.5% by weight of an organic solvent, butylcellulose, 22.5% by weight of ethylcellulose, and 5% by weight of carboxymethyl cellulose acetate butyrate (CM-CAB) resin (14% by weight of nonvolatile matter) were added and mixed for 30 minutes. Then, 60% by weight of the modified acrylic resin (10.4% by weight of non-volatile content) was added and stirred, and when the solution became a completely uniform solution, 2.5% by weight of Glide450 (manufactured by Tego) as a slip agent and BYK-333 (by BYK) as a leveling agent Product) 2.5% by weight of an antistatic coating was obtained.

Example 3

5% by weight of an organic solvent, butylcellulose, 15% by weight of ethyl cellulose, and 5% by weight of carboxymethyl cellulose acetate butyrate (CM-CAB) resin (14% by weight of nonvolatile matter) were added and mixed for 30 minutes. Then, 70% by weight of the modified acrylic resin (10.4% by weight of non-volatile content) was added and stirred, and when the solution became a completely uniform solution, 2.5% by weight of Glide450 (manufactured by Tego) as a slip agent and BYK-333 (by BYK) as a leveling agent Product) 2.5% by weight of an antistatic coating was obtained.

Evaluation of Antistatic Film for Plastics of Antistatic Coatings for Plastics

The antistatic coating for each of the plastics prepared by Examples 1 to 3 was applied to the plastic (ABS or MPPO) to a thickness of 20 to 30㎛ by spray coating, and dried in an oven at about 80 ℃ for 28 to 32 minutes To obtain an antistatic film for plastic. In addition, the physical properties of the antistatic film specimens for plastics were measured according to the following physical property measurement method. The results are shown in Table 1 below. At this time, the antistatic effect was evaluated by measuring the surface resistance. The general antistatic effect is very good at 10 ⁷ to 10 ⁹ Ω / square, good at 10 ⁹ to 10 ¹⁰ Ω / square, good at 10 ¹⁰ to 10 ¹¹ Ω / square, normal at 10 ¹¹ to 10 ¹² Ω / square, It is evaluated as defective above 10 ¹² Ω / square.

TABLE 1

division Example 1 Example 2 Example 3 Surface resistance (Ω / square) 10 ⁹ 10 ⁹ to 10 ⁸ 10 ⁷ Gloss (60 °) 85 85 84 Adhesion 100/100 100/100 100/100 Scratch resistance ◎ ◎ ◎ Transparency and Appearance ○ ○ ○ ◎: Excellent, ○: Good, ×: Poor

(1) Surface resistance: The antistatic film was baked (heated and solidified), cooled at room temperature for 2 hours, and measured using a surface resistance meter (M475 by ACI). The measuring range of the meter is 10 ⁴ to 10 ¹⁴ Ω / square.

(2) Gloss: Measured using a gloss meter (by-micro-TRI-gloss). At this time, the gloss has ± 10 depending on the plastic material part, type and inherent gloss.

(3) Adhesiveness: It measured according to JIS-D0202 method.

(4) Scratch resistance: scratched with a fingernail to observe the scratches with the naked eye.

(5) Transparency: The appearance transparency was visually observed.

Referring to Table 1, as can be seen from the physical property evaluation results for Examples 1 to 3, the obtained antistatic coating agent for plastics is very excellent in antistatic properties because the surface resistance is 10 ⁹ Ω / square or less, Various physical properties such as gloss, adhesion, scratch resistance and transparency are excellent or good.

The antistatic coating agent for plastics according to the present invention as described above exhibits excellent antistatic effect when forming an antistatic film for dried plastic of 5 to 30 μm on the surface of the plastic, as well as adhesion to the plastic material, gloss , Scratch resistance and transparency have excellent properties. Therefore, it can be usefully used as automotive parts or high-tech electronic materials used plastic materials.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (6)

50 to 70 wt% of modified acrylic resin; 5 to 10% by weight of Carboxymethyl Cellulose Acetate Butyrate resin; 5 to 10% by weight of an additive comprising a slip agent and a leveling agent; And Antistatic coating for plastics containing 20 to 40% by weight of an organic solvent. The antistatic coating agent for plastic according to claim 1, wherein the modified acrylic resin is an acrylic resin copolymerized with quaternary ammonium. The antistatic coating for plastics according to claim 1, wherein the additive comprises 2.5 to 5% by weight of slip agent and 2.5 to 5% by weight of leveling agent. The antistatic coating according to claim 1, wherein the nonvolatile content of the modified acrylic resin is 9 to 15% by weight, and the nonvolatile content of the carboxymethyl cellulose acetate butyrate resin is 12 to 20% by weight. For plastics comprising 50 to 70% by weight of modified acrylic resin, 5 to 10% by weight of carboxymethyl cellulose acetate butyrate resin, 5 to 10% by weight of additives including slip agent and leveling agent and 20 to 40% by weight of organic solvent Forming an antistatic coating; And Spray coating the antistatic coating on the surface of the plastic to form a plastic antistatic film comprising the step of producing a plastic antistatic film.  6. The method of claim 5, wherein the plastic antistatic film is formed to a thickness of 20 to 30㎛.