JPH066678B2 - Coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention is characterized by containing a novel fluorine monomer as one component, and is polymerized by energy rays such as ultraviolet rays or electron beams to give a surface. Relates to a composition which forms a coating excellent in smoothness, friction reducing property and water / oil repellency.

<Prior art> As a method for protectively coating the surface of metal, plastic, porcelain, glass, etc., a curable resin material such as a polymerizable monomer or a prepolymer of these is applied to the surface and then cured by irradiation with energy rays. There is known a method of polymerizing a reactive resin material to form a strong cured resin coating on the surface.

In this method, in recent years, it has been noticed that the surface formed from a polymer of a fluorinated alkyl group has a low surface energy, and a fluorinated alkyl group-containing monomer is used as one component of a curable resin composition to produce a solvent resistant composition. Resistance, wear resistance,
Motivation to form a film with excellent friction reduction properties has increased, and it is applied not only to the protective coating of various molded products but also to the surface coating of electrophotographic image carrier and magnetic tape, magnetic disk, etc. It became so. For example, U.S. Pat.Nos. 2,803,615, 2,642,416 and 3,384,627,
No. 3419602, No. 3719698, No. 3981928, No. 3102103
Nos. 3171861, 3818074, 3814741 and the like, a compound containing one perfluoroalkyl group and one vinyl group in one molecule, or A technique of adding a compound in which vinyl groups are linked to both ends of a fluorooxyalkylene group via a divalent linking group to a curable resin composition to perform coating with high solvent resistance (JP-A-57). -16067).

A technique for coating the above-mentioned fluorine-containing vinyl monomer on the magnetic surface side of a magnetic recording medium and curing with an energy ray to obtain a magnetic surface protective layer excellent in abrasion resistance and friction reduction property (JP-A-59- 28244 publication).

The energy ray-curable composition contains 1,1,1,3,3,3-hexafluoropropyl (meth) acrylate or perfluoroethoxy-1,1-dihydroperfluoropropyl (meth)
Add a fluorine-containing vinyl monomer such as acrylate,
A technique of applying such a composition to the surface of a plastic or metal and curing it to form a film having excellent smoothness and abrasion resistance (Japanese Patent Laid-Open No. 52-105936).

There is a suggestion such as.

<Problems to be Solved by the Invention> These conventionally used perfluoroalkyl group- or perfluoroalkylene group-containing vinyl monomers have poor compatibility with non-fluorine-based components and are obtained by curing with energy rays. The cured coating film does not have sufficient friction-reducing property, homogeneity and smoothness, and does not satisfy the surface characteristics required for magnetic tapes or magnetic disks. On the other hand, a vinyl monomer containing a partially fluorinated alkyl group such as 1,1,1,3,3,3-hexafluoropropyl (meth) acrylate is used as the fluorinated vinyl monomer, and Attempts have been made to increase the compatibility, but since the surface energy of the cured coating film cannot be sufficiently lowered by such a method, the friction reducing property, the homogeneity and the smoothness are insufficient. At present, the surface characteristics cannot be satisfied again.

<Means for Solving Problems> The inventors of the present invention have conducted diligent research to solve the above problems, and as a result, have two or three perfluoroalkyl groups in one molecule. A fluorine compound in which an alkyl group is linked to an acryloyl group or a divalent linking group having a specific structure has good compatibility with a non-fluorine-based component, and after curing with energy rays, conventional fluorine-containing vinyl is used. Shows much better surface properties than monomers or fluorinated surfactants, namely friction reduction, homogeneity, smoothness, scratch resistance, rust resistance, moisture resistance, solvent resistance, water and oil repellency, etc. They have found that they can be surface modifiers and have completed the present invention.

One of the objects of the present invention is to provide a coating composition which is polymerizable and curable by energy rays and which comprises a novel fluorine monomer imparting excellent compatibility and surface characteristics as described above in general formula [I]. To do.

The novel fluorine-containing monomer according to the present invention (hereinafter referred to as reactive fluorine-containing surface modifier) has the general formula [I] [In the formula, R _f is a perfluoroalkyl group having 3 to 20 carbon atoms, and Z ₁ is (However, R ₁ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), Or (However, n is an integer of 1 to 6.) and Z ₂ is (However, m is an integer of 2 to 6.), or And R is a hydrogen atom, a methyl group, or a halogen atom such as C
l, Br, etc., and X is (However, Y is a divalent linking group having 15 or less carbon atoms and having a weight ratio in the X group of 35 to 65%.), Which is a divalent linking group represented by p And q are integers satisfying p + q = 4 (where p is 2 or 3), and A is Or Is a tetravalent linking group represented by. ] A reactive fluorine-containing surface modifier comprising a compound having a specific structure represented by

Incidentally, in the general formula [I], two contained Z ₁ are as described above. And It may be two different kinds of connecting groups selected from the above.

In the reactive fluorine-containing surface modifier according to the present invention, R _f is a perfluoroalkyl group or perfluoroalkenyl group having 3 to 20 carbon atoms, which may be linear, branched, cyclic or a combination thereof. Well, with an oxygen atom intervening in the main chain, for example (CF ₃ ) ₂ CFOCF ₂ CF
₂ -or the like.

A typical example of the Y group in the X group, which is a divalent linking group, is: Etc.

Specific examples of the reactive fluorine-containing surface modifier according to the present invention include the following, but it goes without saying that the present invention is not limited to the following compounds.

The method for producing the reactive fluorine-containing surface modifier according to the present invention is not particularly limited, but fluorine-containing alcohol R _f -Z ₁ -OH [II] hydroxyl group-containing (meth) acrylate compound Diisocyanate compound OCN-Y-NCO [IV] Tetrahydric alcohol compound [However, R _f , Z ₁ . R, Z ₂ and Y are as described above. ], It is easily produced in good yield.

That is, the fluorine-containing alcohol [II] and the diisocyanate compound [IV], and the hydroxyl group-containing (meth) acrylate compound [III] and the diisocyanate compound [IV], respectively, in a molar ratio of 0.9: 1 to 1: 0.9. Reacts, And To manufacture. Thereafter, the compounds [VI], [VII], and the tetravalent alcohol compound [V] were mixed at a molar ratio of 3: 1 :.
The reaction is carried out at 0.9 to 3: 1: 1.1 or 2: 2: 0.9 to 2: 2: 1.1 to produce the target reactive fluorine-containing surface modifier [I] according to the present invention.

The solvent that can be used in the reaction is not particularly limited as long as it does not react with the isocyanate group,
Examples thereof include acetone, methyl ethyl ketone, methyl isobutyl ketone, acetonitrile, dimethylformamide, dimethylsulfoxide, ethyl acetate, butyl acetate, tetrahydrofuran, benzotrifluoride, and the like.

The reaction of the fluorine-containing alcohol [II] with the diisocyanate compound [IV], and the hydroxyl group-containing (meth) acrylate compound [III] with the diisocyanate compound [IV],
It is carried out in the temperature range of 0 to 120 ° C, preferably 30 to 90 ° C. The reaction of the compounds [VI] and [VII] with the tetravalent alcohol compound [V] is carried out at a temperature of 0 to 150 ° C, preferably 30 to 100 ° C.

In the above production method, a tetravalent alcohol compound [V] is added to
The by-product of addition of 1 compound (VI) and 3 compounds (VII), and further by addition of 4 compounds [VII] are by-produced, but these are mixed in the compound [I]. However, the surface characteristics referred to in the present invention are not adversely affected.
If necessary, it may be purified by dispersion by gel permeation chromatography.

Fluorine-containing alcohol [II], hydroxyl group-containing (meth) acrylate compound [III], diisocyanate compound [I
V] and tetravalent alcohol [V] can be purchased commercially.

The reactive fluorine-containing surface modifier according to the present invention can be used alone or as a coating composition together with a photopolymerization initiator (D) described later, but it is economical and various from the technical viewpoint. From the viewpoint of the adhesion of the coating film to the material, it is preferable to use it together with a non-fluorine-based component, that is, a hydrocarbon-based acrylate (B) or (C) described below.

The hydrocarbon-based acrylates (B) and (C) referred to in the present invention have one or two acryloyl groups and are known in the art (for example, “Kiyoshi Kato” and “Shoji Nakahara” “Introduction to UV Curing Technology”). Polymer Society, 1984,
Tables 10 and 4 on pages 34 and 35 in [hereinafter referred to as books]
Table 16 on pages 6 to 48, Table 20, pages 170 to 172
It can be appropriately selected from the compounds listed in Table 60 on the page), and examples thereof include the following (B) and (C).

Compound containing one acryloyl group (B) B-1 CH ₂ = C (R ₃ ) COOR ₄ (R ₄ is an alkyl group having 1 to 20 carbon atoms) B-2 CH ₂ = C (R ₃ ) COOCH ₂ CH ₂ OH (However, R ₃ is —H or —CH _3. ) and the like.

Compound (C) containing two or more acryloyl groups (However, R ₃ is —H or —CH _3. ) and the like.

In the coating composition comprising the reactive fluorine-containing surface modifier (A) according to the present invention and the hydrocarbon-based acrylates (B) and (C), the mixing ratio of (A) and (B) + (C) Is from 0.05 / 95.95 to 18.0 / 82.0 in terms of the former / latter weight ratio from the viewpoints of economical efficiency and smoothness and homogeneity of the obtained coating film.

For the above coating composition, a so-called photopolymerization initiator known in the art (for example, Table 22 on page 62 and Table 27 on page 71 of the above-mentioned document) is used.
Etc., that is, for example, D-1: benzophenone, D-2: acetophenone, D-3: benzoin,
D-4: Benzoin ethyl ether, D-5: Benzoin isobutyl ether, D-6: Benzyl methyl ketal, D-7: Azobisisobutyronitrile, D-8: 1
-Hydroxycyclohexyl phenyl ketone, D-9:
2-hydroxy-2-methyl-1-phenyl-1-one and the like and a photosensitizer (for example, Tables 28 and 7 on page 72 of the aforementioned book).
The compounds listed in Table 29 on page 3), solvents, and various additives can be added. The solvent is not particularly limited as long as it does not adversely affect the reactivity of the acrylate monomer, but methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl acetate, ethyl acetate, chloroform, dichloroethane, carbon tetrachloride, 1-fluoro- A 1-dichloro-2-difluoro-2-chloroethane-based low boiling point solvent is preferred. Examples of the additives include leveling agents and defoaming agents.

When carrying out the film formation according to the present invention by ultraviolet rays,
Reactive fluorine-containing surface modifier (A) and hydrocarbon-based acrylate (B), (C) are not substituted by α carbon (that is, R and R ₃ cohydrogen atoms in the above general formula and specific compounds) Are preferred.

As the method for applying the coating composition according to the present invention to the substrate, various methods known in the art as described above can be used, and it is preferable to properly use them according to the material, shape, application, etc. of the substrate. . As the application form of the composition, the composition may be directly applied to the application, and when the viscosity is too high or the film thickness is controlled, the composition is applied as a solution in which the composition is dissolved in a solvent. can do.
In the case of this solution, before irradiation with ultraviolet rays or electron beams,
A step of removing the solvent at room temperature or, if necessary, by heating or reducing pressure is required. When the solvent is removed by heating, it is preferable to carry out the heating at 80 ° C. or lower in order to prevent the heat polymerization of the monomers and the like.

Fluorine-containing protective coating according to the present invention, the coating layer formed on the substrate by the above method, known in the art, germicidal lamp, ultraviolet fluorescent lamp, carbon arc, xenon lamp, high pressure mercury lamp for copying, medium pressure Alternatively, it is formed by irradiating a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an electrodeless lamp, a metal halide lamp, ultraviolet rays using a light source such as natural light, or an electron beam from a scanning or curtain type electron beam accelerating path. Thickness is 5μ
In the case of ultraviolet curing of a coating layer having a thickness of m or less, it is preferable to irradiate under an inert gas atmosphere such as nitrogen gas from the viewpoint of efficient polymerization.

<Function> As described above, there is a proposal to improve the surface characteristics of the cured coating film by adding a fluorine-containing vinyl monomer to the non-fluorine-based component. However, according to the findings of the present inventors,
Conventionally proposed perfluoroalkyl group- or perfluoroalkylene group-containing vinyl monomers cause phase separation due to poor compatibility with non-fluorine-based components, and significantly impair the homogeneity of the coating film. Does not exhibit friction reduction, rust prevention, scratch resistance, etc. On the other hand, there is also an example in which a fluorine-containing vinyl monomer containing a partially fluorinated alkyl group is used to improve the compatibility, but in such a system, the surface migration of the fluorinated alkyl group is poor, The reality is that they do not exhibit sufficient surface properties.

On the other hand, the reactive fluorine-containing surface modifier according to the present invention does not reduce the compatibility with the non-fluorine-containing component because it has an appropriate lipophilic group, and also has a perfluoroalkyl group in one molecule. It is considered that the surface transferability is not impaired due to the inclusion of two or three. For this reason, a microscopically strict aggregate of perfluoroalkyl groups is formed on the surface of the coating film, which is homogeneous and has a friction resistance reduction property, smoothness, scratch resistance, rust resistance, moisture resistance, solvent resistance, It is presumed that a surface having excellent water and oil repellency can be obtained. It should be noted that the above speculation is for helping to understand the present invention, and it goes without saying that the present invention is not limited at all.

<Effects of the Invention> The reactive fluorine-containing surface modifier used in the present invention is not only a component of the energy ray polymerization-curable composition, but also utilizes the reactivity of the vinyl group to form a monomer for the thermosetting resin. Alternatively, it can also be used as a manomer for ordinary solution polymerization.

As described above, the coating composition according to the present invention is used as a protective coating layer for various solid surfaces, such as a moisture-proof rust preventive agent, an antifouling agent, a lubricant, an antifriction agent, a release agent, a release agent, an electronic component, etc. It can be used as a stopper, etc., but especially by taking advantage of the thinness and smoothness of the coating,
It is preferably used for coating a magnetic layer of a magnetic recording product in the field of recording materials.

For example, non-magnetic metals such as copper, aluminum and zinc; polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate; polyolefins such as polypropylene; and plastics such as cellulose derivative polycarbonate such as cellulose acetate; Ferromagnetic alloys (based on iron, cobalt and / or nickel with small amounts of aluminum, silicon, chromium, manganese, molybdenum, titanium, etc., deposited on ceramics such as glass, paper, wood, fibers, porcelain and pottery. (Including various heavy metals, rare earth metals, etc.) or in the presence of a trace amount of oxygen, a magnetic tape obtained by evaporating a magnetic material such as iron, cobalt, or chromium on a plastic film such as polyester, or a protective coating for the magnetic layer of a magnetic disk, etc. ,
It is also suitable as a back surface treating agent for magnetic tapes, which requires particularly anti-friction. Further, by dispersing magnetic powder in the coating composition of the present invention, it is possible to obtain an energy ray-curable magnetic binder having smoothness, anti-friction, etc. and rust prevention.

On the other hand, since the coating composition of the present invention can form a transparent and smooth thin coating on the glass surface, it is also used as an oil stain prevention agent for various optical devices in applications requiring oil resistance and wiping resistance. can do.

Furthermore, it is also suitable as a protective coating agent for optical fibers and optical fiber cables that are particularly required to have moisture proof properties.

Further, since the coating composition of the present invention can form a coating having excellent scratch resistance, it can be used as a hard coating agent for various molded articles or films, sheets and the like.

Furthermore, a pigment and a dispersant are mixed in the composition of the present invention,
A paint or ink excellent in antifouling property or non-adhesiveness can be formed.

Next, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited to such examples. In the text, "part" and "%" are based on weight.

Fluorine-containing alcohol in a 500 ml 4-neck round bottom flask. 87.7 g (0.15 mol), 2-hydroxyethyl acrylate 5.8 g (0.05 mol), hydroquinone 0.2 g, 2,4-
34.8 g (0.20 mol) of tolylene diisocyanate and 100 g of tetrahydrofuran were weighed and placed under a nitrogen atmosphere 6
Reaction was carried out at 4 ° C for 4 hours. After lowering the temperature in the system to 40 ° C., 14.6 g (0.05 mol) of N, N, N ′, N′-tetra (2-hydropropyl) ethylenediamine was added, and the reaction was carried out again at 64 ° C. for 6 hours. After confirming the disappearance of the isocyanate group by titration, tetrahydrofuran was distilled off under reduced pressure to obtain 128.5 g of a pale yellow paste-like crude product.
Got This crude product can be directly used as a coating agent, but if necessary, it can be purified as follows.

When the tetrahydrofuran solution of the above crude product was applied to GPC (column: Hitachi, Gelco GL-A130, 8 mmφ x 500 mm, eluent: tetrahydrofuran, detection: ultraviolet absorption meter, 254 nm), several small particles were observed before and after the main peak. The peak was obtained. The ratio of the main peak area to the total peak area was 69%.

The main peak was collected and subjected to ¹ HNMR measurement, IR measurement, and elemental analysis (see Table 1). As a result, it was confirmed that the target reactive fluorine-containing surface modifier was used.

The fluorine-containing alcohol of Synthesis Example 1 and 2,4-tolylene diisocyanate were each added to C ₈ F ₁₇ CH ₂ CH ₂ OH 69.6 g (0.15
Mol), m-phenylene diisocyanate 32.0 g (0.20
Mol) to carry out the reaction and purification in the same manner. The yield of the crude product was 121.3 g, and the area ratio of the main peak by GPC was 67.8%. The main peak is collected and ¹ H-NM
By performing R measurement, IR measurement, and elemental analysis, it was confirmed that the compound was the target compound.

Elemental analysis of Synthesis Example 2 <Examples> Examples 1 to 12 Tables on steel plate (JIS G3141) or aluminum plate (JIS H4000)-
The coating composition of the present invention shown in No. 1 was applied, the solvent was evaporated at room temperature, and then the applied layer was cured by ultraviolet rays or electron beams under the following conditions, and various properties of the coating film were examined. The results are shown in Table-1.

Apparatus: Curing by ultraviolet rays was carried out at 33 ° C. under a nitrogen atmosphere, using a high pressure mercury lamp (80 w / cm), an irradiation distance of 10 cm, an irradiation time of 60 seconds. Curing with an electron beam uses a curtain type electron beam accelerator (200kv) with a dose of 10Mrad.
I went there.

Coating method: Reactive fluorine-containing surface modifier according to the present invention
A composition comprising (A), a hydrocarbon-based acrylate (B), (C), and a photopolymerization initiator (D) was diluted to 5% with ethyl acetate and applied with a bar coater to give a nonvolatile content of 0.5 μm. A coating layer was formed.

Surface smoothness: The smoothness of the surface coating film is observed by an optical microscope with a magnification of 160 times for the presence or absence of spots on the coating film, and is classified into 5 stages (5: no spots at all, 4: slight spots in green,
3: The surface has only a few spots, 2: the surface has a few spots, and 1: all the spots are larger.

Surface dryness; ◎ By finger touch ◎ No stickiness at all ○ Mark A little stickiness is felt △ Sign A little stickiness is marked × Mark There is stickiness Surface hardness: It was carried out based on JIS 5400.

Contact angle: The contact angle was measured at 25 ° C. by dropping 6 μm of n-dodecane or water on the measurement surface and using a goniometer type contact angle measuring device manufactured by Elma.

Anticorrosion property: The test piece is dipped in a 20% sodium chloride aqueous solution, and the time until rust is generated in the coating film is observed, and 5 stages (5: 200 hours or more, 4: 150 to 200 hours, 3 :).
100-150 hours, 2: 50-100 hours, 1: 0
It was evaluated at 50 hours).

Substrate eye test 1 cm square is cut by 1 mm and cut vertically and horizontally with a cutter to make 100 squares. Then, cellophane tape (Sekisui Chemical S-832) was adhered, peeled off at a stretch, and the number of remaining squares was shown. .

In the columns of Examples and Comparative Examples No., UV display shows formation of a polymer film by ultraviolet curing, and EB display shows that of electron beam curing. Further, A, B, C and D in the table represent the compounds in the text, respectively.

Examples 15 to 21 Next, on a polyester film, Examples 1 to 1 shown in Table 1
A coating film was formed with the same composition as that of No. 14, and its surface smoothness, surface drying property, contact angle and sliding angle of n-dodecane, and friction resistance reduction property were examined. The results are shown in Table-2.

The dynamic friction coefficient is measured according to the American Society for Testing Materials standard D-18.
A friction test jig manufactured by Toyo Baldwin Co., Ltd. was used (weight of 236 g, tensile strength: 100 mm / min) according to the method of 94.

Examples 22 to 26 Next, a coating composition having the following composition was applied to a polyester film, and after being cured by ultraviolet rays, the solvent resistance stability was examined, and the results are shown in Table 3.

The solvent was acetone, and the coated film was immersed in acetone for 1 hour and then pulled up, and the state of the coating film was displayed in three stages.

Coating thickness: 15 μm Composition of coating composition: Example 27 A crude product of A-2 synthesized in Synthesis Example 1, a purified reactive fluorine-containing surface modifier (main peak), and 10.0 parts each of the remaining components from which the main peak was separated were added to C- 8 (R ₃ =
H) 40.0 parts, C-13 (R ₃ = H) 40.0 parts, B-7 (R
₃ = H) was mixed with 7.0 parts and D-83.0 parts to prepare a composition in the same manner as in Example 2, and the composition was applied to a steel plate and UV-cured. When the crude product was blended, almost the same surface properties were obtained as when the main peak was blended, but when the remaining components from which the main peak was separated were blended, the surface properties were significantly inferior.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08F 220/28 MML 7242-4J 220/36 MMQ 7242-4J 220/38 MMU 7242-4J

Claims (1)

[Claims] 1. A general formula [I] [In the formula, R _f is a perfluoroalkyl group having 3 to 20 carbon atoms, and Z ₁ is (However, R ₁ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), Or (However, n is an integer of 1 to 6.) and Z ₂ is (However, m is an integer of 2 to 6.), or And R is a hydrogen atom, a methyl group, or a halogen atom, and X is (However, Y is a divalent linking group having 15 or less carbon atoms and having a weight ratio in the X group of 35 to 65%.), Which is a divalent linking group represented by p And q are integers satisfying p + q = 4 (where p is 2 or 3), and A is Or Which is a tetravalent linking group represented by] and a hydrocarbon-based (meth) acrylate, and the former and the latter are 0.05 / 99.95 to 18.0 / 82.0 (weight ratio) A coating composition capable of being polymerized by energy rays, characterized in that