JPH0892497A - Antistatic ultraviolet-curing coating material and optical disc made by using the same - Google Patents

Abstract

PURPOSE: To obtain a coating material which can impart antistatic properties to a polymer molding and is improved particularly in storage stability. CONSTITUTION: This material is obtained by mixing 100 pts.wt. copolymerizable (meth)acrylic ester, 0.1-5 pts.wt. perfluoroalkylated surfactant represented by the formula CF3 (CF2 )n AM (wherein A is CO2 or SO3 ; M is an alkali metal; and (n) is an integer of 3 to 9), and 0.2-10 pts.wt. photopolymerization initiator.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an antistatic coating for synthetic polymer material moldings, which has good storage stability and is capable of forming a cured film having excellent scratch resistance, antistatic property and durability. The present invention relates to a material, particularly an ultraviolet curable coating material, and an optical disk provided with a cured coating of the coating material.

[0002]

2. Description of the Related Art Synthetic polymer molding materials usually have a property that they are easily charged due to their large hydrophobicity. Such characteristics are such that polymer molding material molded products suck dust, and electrification causes electric shock, ignition, etc. And is a hindrance to the use of products using these materials.

Conventionally, conductive agents such as carbon black and conductive metal powders have been used to prevent electrification of polymer material moldings.
Alternatively, attempts have been made to prevent the above-mentioned various troubles by kneading a surfactant or the like into a polymer material, or by applying these antistatic agents to the surface of a molded product.
For example, JP-A-63-307947 discloses a film in which a charge transfer complex is coated.
However, if an attempt is made to obtain a resin molded product having desired antistatic properties by using a conductive agent such as a charge transfer complex, the amount used will increase, and other properties of the resulting molded product will tend to be impaired. is there. In addition, it is difficult to add the charge transfer complex to the organic polymer, and it is difficult to obtain a molded product having good transparency. Further, the conductive agent is expensive, and the desired antistatic property is obtained. It is quite expensive to install and not common.

On the other hand, many types of antistatic agents, which are mainly surfactants, are known, and there is an advantage that they can be appropriately selected and used according to desired characteristics. Among these antistatic agents, many proposals have been made as an internal addition type which is kneaded into a polymer material and used, but there are still various problems. For example, JP-A-63-
The antistatic agent disclosed in JP-A-314261 is
Although it has good antistatic properties, it is generally difficult to use as an antistatic agent for coating materials. On the other hand, a coating type coating material which imparts antistatic property to the surface of a polymer material molded article is used as a surfactant alone or in the form of a mixture of these surfactants with a polymer or other substance. Some conventional antistatic agents do not provide sufficient effect at low humidity, and the coating film drying process after coating onto molded products, heating during stretching, heat setting, heat molding, etc. of coated molded products In many cases, the antistatic effect is lost due to rubbing, washing, etc., and the durability is insufficient. Therefore, development of an antistatic agent having good durability has been desired.

As a solution to such a problem, Japanese Patent Laid-Open No.
No. 3-6064 discloses an antistatic agent to which a phosphoric acid ester is added, and JP-A No. 2-186598 proposes an antistatic agent to which a fluorine compound is added and which has a balanced compatibility. However, when a product coated with this antistatic agent is subjected to a long-term durability test such as a moisture resistance test, the balance of the mechanical strength of the coating film, the durability of the antistatic performance, etc. becomes unbalanced, and it has the desired characteristics. The antistatic agent still had some problems to be solved.

A coating film formed from a UV-curable coating material has excellent adhesion to the substrate, and thus has a wide selection range of the substrate and a short coating film forming treatment time. It is possible to form coating films with excellent coating film performance such as chemical resistance, scratch resistance, and abrasion resistance.
This coating film has a problem that static electricity is generated due to friction and the like, and dust is likely to adhere to the coating film.

The inventors of the present invention previously disclosed in Japanese Unexamined Patent Publication No. 4-80267.
JP-A-4-180970 and JP-A-4-180970 proposed an ultraviolet curable coating material using a thiocyanate having an antistatic function. The coating film formed from this coating material was charged at the beginning of film formation. Although the goal of preventive effect could be achieved, it was surprisingly found that it is difficult to store the coating material for a long period of time. Therefore, as a result of further intensive studies, the present invention has been achieved.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides an excellent coating film formed from a conventional UV-curable coating material by adding a surfactant having a perfluoroalkyl group to the UV-curable coating material. It has various properties such as transparency, scratch resistance and solvent resistance, and can form a coating film without surfactant bleed-out on the surface of the cured coating film for a long period of time, and also has excellent storage stability. It was successful in obtaining a coating material. An object of the present invention is to provide a coating material capable of imparting antistatic performance to a polymer molding, particularly a coating material having improved storage stability.

[0009]

The present invention relates to a surfactant having a perfluoroalkyl group represented by the following general formula (1) per 100 parts by weight of a copolymerizable (meth) acrylic acid ester. An antistatic UV-curable coating material in which 0.1 to 5 parts by weight and 0.2 to 10 parts by weight of a photopolymerization initiator are mixed,

[0010]

[Chemical 2]

Further, there is provided an optical disk which is provided with a cured coating film of the above coating material on at least one surface of a plastic optical disk and which is excellent in antistatic property and scratch resistance.

In the coating material of the present invention, copolymerizable (meth) acrylic acid esters are used as a cross-linking agent, and have scratch resistance of a coating film formed from the coating material of the present invention and surface protection effect of a substrate. Bring out. The copolymerizable (meth) acrylic acid ester is preferably a compound having at least one (meth) acryloyl group and at least one hydroxyl group in one molecule.

Such copolymerizable (meth) acrylic acid esters having a (meth) acryloyl group and a hydroxyl group include (a) a compound having three or more (meth) acryloyl groups, and (b) a (meth) acryloyl group. A compound having two groups, (c) a compound having one (meth) acryloyl group, and (d) a compound having at least one hydroxyl group and having a (meth) acryloyl group other than the above (c) More preferably, it is configured by a combination.

Examples of the compound (a) include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tetra ( (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like, and the preferable amount thereof is a combination of the compounds (a) to (d). It is 20 to 60% by weight with respect to the total amount, and when the amount used is less than 20% by weight, the coating film formed from the obtained coating material tends to deteriorate surface protection performance such as scratch resistance.
If it exceeds 0% by weight, the coating film formed from the obtained coating material tends to hinder the surface orientation of the antistatic component and fail to exhibit sufficient antistatic performance.

Examples of the compound (b) include 1,3-
Butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol Di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, bisphenol A
Examples thereof include polyoxyethylene di (meth) acrylate, and the preferable amount thereof is 30 to 70% by weight based on the total amount of the combination of the compounds (a) to (d), and the amount is less than 30% by weight. , The adhesion of the coating film formed from the obtained coating material to the substrate tends to decrease,
If it exceeds 70% by weight, the curability of the obtained coating material tends to be insufficient, and the scratch resistance of the coating film tends to decrease.

Examples of the compound (c) include 2-ethylhexyl (meth) acrylate, ethoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cresol ethoxy (meth) acrylate, isobornyl (meth) acrylate and N-. Methoxymethyl (meth) acrylamide and the like can be mentioned, and the preferable amount thereof is 5 to 30% by weight based on the total amount of the combination of the compounds (a) to (d), and when the amount used is less than 5% by weight, The adhesion of the coating film formed from the coating material to the substrate tends to decrease, and when it exceeds 30% by weight, the curing performance of the obtained coating material tends to decrease.

The compound (d) has at least one hydroxyl group in one molecule and has 1 (meth) acryloyl group.
A compound other than the above-mentioned compound (c) having an individual group is used, and for example, N-hydroxymethyl (meth) acrylamide,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypentyl (meth) acrylate, 4-hydroxypentyl ( Examples thereof include an ethylene oxide or propylene oxide adduct of (meth) acrylate, 2-hydroxyethyl (meth) acrylate or 2-hydroxypropyl (meth) acrylate. The preferred amount used is 1 to 20% by weight based on the total amount of the combination of the compounds (a) to (d). If the amount used is less than 1% by weight, the resulting coating material may be stored for a long time. The antistatic component may be precipitated, and if it exceeds 20% by weight, the curing performance of the obtained coating material tends to deteriorate.

Among the (meth) acrylic acid ester compounds exemplified as the compounds (a) to (d), the compound having an acryloyl group is better in curability than the compound having a methacryloyl group. And is particularly preferable.

The surfactant having a perfluoroalkyl group represented by the general formula (1) contained in the coating material of the present invention only lowers the surface tension of the coating material of the present invention and improves the coating performance. Not only that, it gives a coating film formed from the coating material of the present invention an excellent antistatic effect.

Examples of the surfactant having a perfluoroalkyl group represented by the general formula (1) include lithium perfluorobutyl sulfonate, potassium perfluorobutyl sulfonate, lithium perfluorocaproate, and perfluorocapron. Potassium acid, lithium perfluorohexyl sulfonate, sodium perfluorohexyl sulfonate, lithium perfluoro pelargonate, sodium perfluoro pelargonate, lithium perfluoro octyl sulfonate, potassium perfluoro octyl sulfonate, lithium perfluoro caprate, per Examples thereof include potassium fluorocaprate, lithium perfluorononyl sulfonate, lithium perfluoroundecylate, and the like.

Of these surfactants, a coating film formed from a coating material containing a compound in which n is less than 3 has an insufficient antistatic effect, while a compound in which n exceeds 9 is a coating material. The compatibility with other components in the material is poor, and the coating material containing this compound itself becomes cloudy.

The amount of the surfactant having a perfluoroalkyl group represented by the general formula (1) used is 0.1 with respect to 100 parts by weight of the copolymerizable (meth) acrylic acid ester. ~ 5 parts by weight. When the amount used is less than 0.1 parts by weight, the resulting coating material does not exhibit sufficient antistatic performance, and when it exceeds 5 parts by weight, the curability of the obtained coating material deteriorates and the obtained cured coating material is obtained. Not only does the surface hardness of the film decrease, but bleeding may occur, and the coating material may become cloudy when stored for a long period of time.

The surfactant having a perfluoroalkyl group represented by the general formula (1) in the coating material of the present invention has poor solubility due to its low purity and the required antistatic property. When it is difficult to express the above, a surfactant having a perfluoroalkyl group represented by the following general formula (2) is added to 100 parts by weight of copolymerizable (meth) acrylic acid ester: 0.1-5
When used in combination with parts by weight, the antistatic property can be supplemented.

[0024]

[Chemical 3]

Examples of the photopolymerization initiator in the coating material of the present invention include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetoin, butyroin, toluoin and benzyl which have absorption in the ultraviolet region of 260 to 450 nm. , Benzophenone, p-methoxybenzophenone, diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy −
Carbonyl compounds such as 2-methyl-1-phenylpropan-1-one, tetramethylthiuram monosulfide,
Sulfur compounds such as tetramethylthiuram disulfide,
Examples thereof include azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile, and peroxides such as benzoyl peroxide and ditertiary butyl peroxide.

The above-mentioned photopolymerization initiator may be one kind or a mixture of two or more kinds, and the amount thereof is 0 based on 100 parts by weight of (meth) acrylic acid ester. 2 to 10 parts by weight. If the amount used is less than 0.2 parts by weight, the curability of the coating material will be insufficient and 1
If it exceeds 0 parts by weight, the photopolymerization initiator acts as a plasticizer, the cured film does not have sufficient hardness, and gelation may occur when the coating material is stored for a long period of time.

The coating material of the present invention may appropriately contain conventionally known additives, that is, a surface conditioner, an ultraviolet absorber, an antioxidant, a low-shrinking agent, etc., within a range that does not impair the antistatic property. it can.

The coating material of the present invention obtained by blending the above-mentioned respective components can be cured by ultraviolet rays, and its coating method and curing method are not particularly limited. Ultraviolet light sources used for curing include ultrahigh pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, low pressure mercury lamps, metal halide lamps, xenon lamps, gallium lamps, and sunlight.

The coating film formed from the coating material of the present invention has more excellent scratch resistance and solvent resistance than the coating film formed from the conventional UV-curable coating material, and has a permanent antistatic property. Have.

The coating film formed from the coating material of the present invention has particularly excellent antistatic properties and can impart good antistatic properties to acrylic resins, polycarbonate resins and the like, and in particular, plastic optical disks. Among them, a polycarbonate optical disk provided with a cured coating film of the coating material of the present invention can have excellent antistatic property and scratch resistance.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, the part in an Example means a weight part. Also,
The evaluation items in the examples are based on the following methods.

Surface resistance value: Advantest TR-86
Measured with 01 type. Applied voltage 100V, 1 minute value. Charging half-life: measured with a static paper analyzer SP-428 type manufactured by Kawaguchi Denshi Co., Ltd. at an applied voltage of 8 KV. Surface condition: Measure the haze value (%) of the coating film after a 500g weighted Taber abrasion test, and measure the coating film in a moisture resistance test (80 ° C,
(85% RH, 100 hours) visually evaluated the appearance. Adhesion: The coating film is subjected to a scotch tape test according to JIS K5400, and the number of squares remaining without peeling is measured.
Displayed by the remaining squares / 100. Storage stability: coating material in a constant temperature water bath at 40 ℃
The state after processing for 000 hours was visually evaluated.

Examples 1 to 7 Compositions (A) to (C) of copolymerizable (meth) acrylic acid esters and photopolymerization initiators having the constitution shown in Table 1 have a perfluoroalkyl group. A surfactant was blended uniformly in an amount shown in Table 2 to obtain a coating material. This coating material has a dry film thickness of 10
The coating film was applied onto a polycarbonate molding plate with a bar coater so as to have a thickness of μm, and was irradiated with ultraviolet rays to form a cured coating film. The coating film was evaluated for antistatic performance and storage stability. The evaluation results are shown in Table 3.

(Example 8) The coating material obtained in Example 1 was filtered through a 0.2 μm membrane filter, and then dried with a spin coater under an environment in which suspended particles per 1 ft ³ were 1,000 or less. The coating film was applied on a polycarbonate optical disk substrate so that the thickness was 4 to 5 μm, and was irradiated with ultraviolet rays of 1,000 mj / cm ² by a high pressure mercury lamp of 80 W / cm set to a distance of 10 cm from the lamp, and a cured coating film. An optical disk plate having The coating film was evaluated for antistatic performance, disk performance and storage stability, and the evaluation results are shown in Table 3.

Comparative Examples 1 to 8 Compositions (A) to (H) of copolymerizable (meth) acrylic acid esters having the constitution shown in Table 1 and a photopolymerization initiator have a perfluoroalkyl group. A surfactant was blended uniformly in an amount shown in Table 2 to obtain a coating material. Using this coating material, a cured coating film was formed in the same manner as in Example 1, and the coating film was evaluated for antistatic performance and storage stability. The evaluation results are shown in Table 3.

Comparative Example 9 A coating material obtained by dissolving 0.1 part of lithium perfluorooctylsulfonate and 5 parts of polymethylmethacrylate in acetone as a surfactant having a perfluoroalkyl group on a polyester film was obtained. After coating and drying at 75 ° C., it was cooled. The coating film was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

In Table 3, the values in the upper row show the initial values after forming the coating film, and the values in the lower row show the coating film in a moisture resistance test (80 ° C, 85 ° C).
% RH, 100 hours).

[0041]

EFFECT OF THE INVENTION The antistatic UV-curable coating material of the present invention has excellent performances in transparency, scratch resistance and solvent resistance, has permanent antistatic property, and has a surface for a long time. It is possible to form a coating film without bleeding and is excellent in storage stability. Further, the coating material of the present invention is applied to a polymer molding material, and a plastic optical disk on which a cured coating film of the coating material of the present invention is formed has excellent antistatic property and scratch resistance. You can

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Mita 4-60 Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (5)

[Claims] 1. A surfactant having a perfluoroalkyl group represented by the following general formula (1) 0.1 to 100 parts by weight of a copolymerizable (meth) acrylic acid ester.
An antistatic UV-curable coating material in which 5 parts by weight and 0.2 to 10 parts by weight of a photopolymerization initiator are mixed. [Chemical 1] 2. The antistatic property according to claim 1, wherein the copolymerizable (meth) acrylic acid ester is a compound having at least one (meth) acryloyl group and at least one hydroxyl group in one molecule. UV curable coating material. 3. A copolymerizable (meth) acrylic acid ester having 20 to 60% by weight of a compound having (a) three or more (meth) acryloyl groups and (b) having two (meth) acryloyl groups. 30 to 70% by weight of compound, 5 to 30% by weight of compound having one (c) (meth) acryloyl group
And (d) a compound having at least one hydroxyl group and having one (meth) acryloyl group other than the compound (c) 1 to
The antistatic UV-curable coating material according to claim 1, which is composed of a combination of 20% by weight. 4. An optical disc having excellent antistatic properties and scratch resistance, which is obtained by providing a cured coating film of the coating material according to claim 1, 2 or 3 on at least one side of a plastic optical disc. 5. The optical disk according to claim 4, wherein the plastic optical disk is a polycarbonate optical disk.