JP2689569B2 - Fluorine-based coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a coloring power composed of an inorganic pigment surface-treated with a fluorine-containing silane compound and a fluorine-based resin as an additive for paints,
The present invention relates to a coating composition excellent in color developability, hiding power, luster, and prevention of pigment settling.

[Conventional technology and problems]

Since the surface of the inorganic pigment is hydrophilic, the dispersibility in a solvent and a solvent-based resin is poor, and generally a surfactant, a dispersant or the like is added to make the surface lipophilic and enhance the dispersion effect. At the time of conversion, shear stress is applied and these treatment agents are easily desorbed, so that the function thereof is not fully exerted. In particular, since the fluororesin itself has low activity, it is difficult to disperse the inorganic pigment and the conventional surface treatment agent has a small effect, so that a treatment agent having particularly good dispersibility is used. However, in the method using the conventional treating agent, the surface of the inorganic pigment is not modified, so that the pigment particles aggregate with the passage of time and the dispersion effect gradually decreases.

In addition, there are few thickeners (thickeners) having an appropriate thickening effect in fluorine-based paints, and the coating method and the like are often limited by the viscosity and viscosity of the resin.

In order to solve the above problems, the inventors of the present invention reduce the surface activity of inorganic pigments and / or thickeners by adding perfluoroalkyl groups to the surface thereof to prevent aggregation of particles, and As a result of research aimed at improving dispersibility in water, it is extremely effective to treat the surface of the inorganic pigment and / or the thickener with the fluorine-containing silane compound represented by the general formula (I) or (II). I found that there is.

[Means for solving the problem]

The present invention provides a fluorine-based coating composition composed of an inorganic pigment and a solvent-soluble fluorine-based resin, which is represented by the general formula R _f (CH ₂ ) _n Y (CH ₂ ) _m SiX ₃ (I) (wherein R _f is C _{1 ~ 20} perfluoroalkyl groups, n and m
Integers each 0 to 3, Y is _{-CH 2 -, - CH 2 O} -, - N
_{R -, - CO 2 -,} - CONR -, - S -, - SO 3 - or -SO ₂
NR-, wherein R is H or a C _1-8 alkyl group, X
Represents Cl, Br, OCH ₃ or OC ₂ H ₅ ) and is a fluorine-based coating composition containing an inorganic pigment and / or a particulate thickener surface-treated with a fluorine-containing silane compound. Provide things.

This fluorine-containing silane compound is preferably represented by the following general formula (II).

C ₈ F ₁₇ S0 'in _{(CH 2) 3 SiX 3 (} II) formula, R' ₂ NR alkyl group of C _{1 ~ 5,} X is Cl, Br, OCH ₃
Or represents OC ₂ H ₅ .

In the present invention, one or both of the inorganic pigment and the thickener are surface-treated with the fluorine-containing silane compound represented by the general formula [1] or [2].

_{R f (CH 2) n Y} (CH 2) m SiX 3 ... (1) wherein perfluoroalkyl group R _f is _{C 1 to 20,} n and m is an integer of from 0 to 3, Y is -CH ₂ −, −CH ₂ O−, −NR
_{-, - CO 2 -, -} CONR -, - S -, - SO 3 -, - SO 2 NR-
(R is H or a C _1-8 alkyl group), X is Cl, Br,
OCH ₃ , OC ₂ H ₅ ] The fluorine-containing silane compound represented by the above general formula [1] is a hydrophobic perfluoroalkyl group R _f which is strongly bonded to the pigment particle surface or the viscous agent particle surface by the —SiX ₃ group. Orients outward to give the pigment particles excellent dispersibility.

In particular, the general formula C ₈ F ₁₇ S0 ₂ NRCH ₂ CH ₂ CH ₂ SiX ₃ [2] [wherein R is H or a C _1-5 alkyl group, X is Cl,
Br, OCH _3, a fluorine-containing silane compound represented by OC ₂ H _5], by having a sulfonyl group and an alkyl group between the -SiX ₃ group with a perfluoroalkyl group [C ₈ F _17], the solvent The compatibility is extremely good, the surface of the inorganic pigment particles and the surface of the viscous agent particles are uniformly modified, and the perfluoroalkyl group is uniformly oriented to the outside to exhibit excellent dispersibility. Therefore, the fluororesin paint containing these pigments and thickeners has markedly improved coloring power, color developability, hiding power, luster and the like.

The inorganic pigment used in the present invention is titanium oxide, white zinc, white lead such as white lead, calcium carbonate, silica powder, barium sulfate, clay, extender pigment such as talc, red iron oxide,
Iron black, yellow iron oxide, ocher, ultramarine, titanium yellow,
Colored pigments such as cadmium yellow, cadmium red, chrome green, yellow lead, and cobalt green, including most inorganic pigments.

Further, as the particulate thickening agent used in the present invention, ultrafine silica powder having an excellent thickening effect is preferably used. As the thickener, for example, Aerosil # 200 (manufactured by Nippon Aerosil Co., Ltd.) or the like is used.

The fluororesin of the composition of the present invention is of a type that is soluble in a solvent, such as Teflon or polyvinylidene fluoride that is not soluble in a solvent and has a high melting point.
As the fluorine-based resin, for example, "Lumiflon" (manufactured by Asahi Glass Co., Ltd.) and the like are used. On the other hand, any resin that cures at room temperature or resin that cures upon baking can be used.

The surface treatment amount of the fluorine-containing silane compound of the inorganic pigment and the thickening agent treated with the fluorine-containing silane compound used in the present invention is 0.1 to 20% by weight with respect to the inorganic pigment and the like, preferably 0.1 to 10% by weight. %. Surface treatment amount is 0.1
If it is less than wt%, the effect of surface treatment is small, and if the amount of surface treatment exceeds 20 wt%, dispersibility in the surface treatment step is insufficient and uniform treatment cannot be performed.

As the surface treatment method for the fluorine-containing silane compound used in the present invention, the fluorine-containing silane is prepared by keeping the inorganic pigment and / or the particulate viscous agent in a fluidized state as it is by stirring or by previously dispersing it in a solvent such as ethanol. A predetermined amount of a compound may be added and surface treatment may be followed by drying, or a fluorine-containing silane compound may be added when preparing a coating material. However, when the fluorine-containing silane compound is used by being added to the coating material, it is possible to disperse the inorganic pigment in the solvent in advance, add the fluorine-containing silane compound for treatment, and then add the fluorine-based resin for uniform treatment. preferable.

〔Example〕

Example 1 100 parts by weight of titanium oxide was stirred with a Henschel mixer at high speed, and a fluorine-containing silane compound C ₈ F ₁₇ SO ₂ N (C ₃ H ₇ ) was added.
A solution prepared by dissolving 0.1 part by weight of (CH ₂ ) ₃ Si (OCH ₃ ) _{3 in} 10 parts by weight of acetone was added dropwise, and after completion of the addition, heat treatment was carried out at 150 ° C. for 1 hour, followed by pulverization with a jet mill and fluorine-containing. Silane-treated titanium oxide was obtained. The titanium oxide was mixed with the additives in the amounts shown in the following table (formulation 1) to obtain a white coating composition. The fluororesin solution was kneaded by adding 47.6 parts by weight,
The remaining 95.3 parts by weight was added together with 13.3 parts by weight of the curing agent isocyanate, and the mixture was stirred and mixed for 15 minutes. 1 part by weight Fluorine-containing silane-treated titanium oxide 30 Fluorine-based resin solution (60% solids) (Lumiflon LF-200C manufactured by Asahi Glass Co., Ltd.) 142.9 Xylene 35.7 Methyl isobutyl ketone 107.1 Isocyanate (hardener) 13.3 This The coating material was applied to a hiding ratio test paper to a thickness of 10 mil and dried to obtain a test piece. L, a and b of the white part were measured by a colorimeter, and the whiteness was calculated from the following formula.

Next, the glossiness of the white portion was measured at 60 °, and the hiding ratio (reflectance of black portion / reflectance of white portion) was determined by a reflectometer. Furthermore, carbon 1 is used instead of 30 parts by weight of titanium oxide.
A black paint having the same composition as in Formulation 1 was prepared except that 5 parts by weight was used, and 30 parts of the black pigment was added to 100 parts by weight of the above white paint.
The coloring power of the above white paint was examined by mixing by weight. Table 1 shows the results.

Comparative Example 1 A white coating material was prepared by the same composition and formulation as in Example 1 except that untreated titanium oxide was used, and whiteness, 60 ° gloss, hiding power, and tinting strength were obtained in the same manner as in Example 1. Examined. Table 1 shows the results.

Example 2 100 parts by weight of titanium oxide was dispersed in a solution prepared by dissolving 10 parts by weight of C ₈ F ₁₇ SO ₂ N (CH ₃ ) (CH ₂ ) ₃ Si (OCH ₃ ) _{3 in} 300 parts by weight of ethanol. Fluorine-containing silane-treated titanium oxide was obtained in the same manner as in. Using this titanium oxide, a white paint was produced by the same composition and treatment as in Example 1, and the same test as in Example 1 was conducted on a test piece coated with this white paint. Table 1 shows the results.

Comparative Example 2 A white paint was prepared in the same manner as in Example 2 except that a fluorine-free silane compound CH ₃ CONH (CH ₂ ) ₃ Si (OCH ₃ ) ₃ was used as a surface treatment agent for titanium oxide. The same test as in Example 1 was performed on the test piece coated with. Table 1 shows the results.

After dispersing the Example 3 Titanium oxide 30 parts by weight 114.2 parts by weight of _{toluene, C 8 F 17 SO 2 N} (CH 3) (CH 2) 3 Si (OC 2 H 5) 3 to 6 parts by weight added to stirrer Fluorine resin solution ("Lumiflon LF100" manufactured by Asahi Glass Co., Ltd., solid content 50%) 1
After adding 71.5 parts by weight and further kneading for 60 minutes, 5.2 parts by weight of melamine as a curing agent was added and mixed with stirring for 15 minutes to obtain a white paint. 70 g / m ^{2 of} this white paint was applied to a polished steel plate and baked at 200 ° C. for 5 minutes to give a test piece, and whiteness, 60 ° gloss and tinting strength were determined in the same manner as in Example 1. Table 1 shows the results.

Example _{4 C 7 F 15 CO 2 (} CH 2) 3 Si (OCH 3) 3 to 5 parts by weight Ethanol 30
After 100 parts by weight of calcium carbonate was dispersed in a solution dissolved in 0 part by weight, the mixture was stirred and mixed for 60 minutes, filtered, and dried to obtain fluorine-containing silane-treated calcium carbonate. A white paint was obtained by mixing the calcium carbonate with the amounts of additives shown in the following table (formulation 2). Calcium carbonate treated with 2 parts by weight fluorine-containing silane 25 Titanium oxide 5 Toluene 114.2 Fluorine resin solution (solid content 50%) (Lumiflon LF-100 manufactured by Asahi Glass Co., Ltd.) 171.2 Melamine (hardener) 5.2 This coating Was coated on a hiding power test paper and baked at 130 ° C. for 40 minutes to give a test piece, which had the same whiteness as in Example 1.
The 60 ° gloss, the hiding ratio, and the coloring power were obtained. This result is
It is shown in the table.

Comparative Example 3 Fluorine-free silane compound C ₃ H ₇ as a surface treatment agent
A white coating material was produced by the same compounding treatment as in Example 4 except that Si (OCH ₃ ) ₃ was used, and the same test as in Example 1 was conducted for this. Table 1 shows the results.

Examples 5 to 11 The inorganic pigments shown in Table 2 were treated with the amounts of fluorine-containing silane compounds shown in Table 2, and then the pigments were added with the amounts of additives shown in the following table (formulation 3). The mixture was mixed to obtain a coating composition. The paint was applied to a slate plate of 50 × 150 mm at 150 g / m ² and L, a and b were obtained as a test piece by a colorimeter. Further, a paint was prepared in the same manner except that 10 parts by weight of titanium oxide was added instead of calcium carbonate, and L, a, and b were similarly determined for test pieces coated with this paint, and the case where titanium oxide was not added The color difference ΔE when added was calculated from the following equation.

Composition 3 parts by weight Fluorine-containing silane-treated pigment 2 Calcium carbonate 10 Toluene 50 Fluorine-based resin solution (“Lumiflon LF-100”) 40 Isocyanate (curing agent) 3.7 The same as the above, except that an untreated inorganic pigment was used. A paint was manufactured by the treatment of No. 1 and the color difference ΔE ′ was similarly determined for the test body coated with this paint. This ΔE / ΔE 'is shown in Table 2 as the whitening rate. Generally, when ΔE / ΔE ′ (whitening rate) is smaller than 1, it is less likely to be affected by the increase in titanium oxide and the coloring power is excellent. As shown in Table 2,
In Examples 5 to 11, ΔE / ΔE 'was smaller than 1 and the coloring power was high. On the other hand, the whitening ratio (ΔE / ΔE ′) of the comparative example is close to 1, and the effect of improving the coloring power is small.

Example 12 As a coating additive having a thickening effect, the surface of ultrafine silica powder “Aerosil # 200” (manufactured by Nippon Aerosil Co., Ltd.) was treated with the fluorine-containing silane compound of Example 2 in the same manner as in Example 1. Was treated to prepare ultrafine silica powder having a treating agent amount of 3.0% by weight. A coating composition was produced using the ultrafine silica according to the following table (formulation 4). A coating material was obtained by adding 2.8 parts by weight of isocyanate as a curing agent. The same test as in Example 1 was conducted on this paint. Table 1 shows the results. 4 parts by weight Fluorine-containing silane-treated ultrafine silica powder 2 Titanium oxide 10 Toluene 60 Low viscosity fluorine resin solution (“Lumiflon LF-300”) 30 Isocyanate (hardener) 2.8 Comparative Example 6 Untreated ultrafine silica A coating material was produced in the same manner as in Example 12 except that powder was used. When this paint was compared with the paint of Example 12, the paint of Example 12 had an increase of 2.3% in whiteness, 3.5% at 60 ° gloss, and 8.4% in hiding ratio as compared with the paint of this comparative example.

After further centrifuging the pigment to examine the sedimentation of the pigment,
When the pigment was allowed to settle by allowing it to stand, the coating using the ultrafine silica powder treated with a fluorine-containing silane compound had a rotation speed of 1000 rpm.
No precipitate was formed even after centrifugation for 30 minutes. The paint using untreated ultrafine silica powder produced a precipitate, indicating that the fluorine-containing silane compound-treated ultrafine silica powder was excellent in thickening.

[Effects of the Invention] As shown in the above Examples and Comparative Examples, the inorganic pigment surface-treated with the fluorine-containing silane compound of the present invention is excellent in whiteness or coloring power, hiding power, and gloss (60 ° gloss). ing. Particularly, a fluorine-containing silane compound represented by the formula (II) having a sulfonyl group and an alkyl group in a side chain exhibits excellent properties. Further, with regard to the pigment composed of titanium oxide, it is effective in reducing the amount used and enhancing the coating film performance. Furthermore, although almost none of the conventional fluorine-based paints have a thickening effect, the paint of the present invention contains an ultrafine silica powder surface-treated with a fluorine-containing silane compound, and therefore has an excellent thickening effect. In addition, the pigment is prevented from settling. As described above, the coating composition of the present invention has various properties and can be widely used for various applications.

Claims (3)

(57) [Claims] 1. A fluorine-based coating composition comprising an inorganic pigment and a solvent-soluble fluorine-based resin, wherein a general formula R _f (CH ₂ ) _n Y (CH ₂ ) _m SiX ₃ (I) (wherein R _f is C A perfluoroalkyl group of _{1 to 20} , n and m are each an integer of 0 to 3, Y is —CH ₂ —, —CH ₂ O—,
_{-NR -, - CO 2 -,} - CONR -, - S -, - SO 3 - or -
SO ₂ NR-, wherein R is H or a C _1-8 alkyl group, and X is Cl, Br, OCH ₃ or OC ₂ H ₅ ) and is surface-treated with a fluorine-containing silane compound. A fluorine-based coating composition comprising a pigment and / or a particulate thickening agent. 2. The fluorine-containing silane compound has the general formula C ₈ F ₁₇ S0 ₂ NR ′ (CH ₂ ) ₃ SiX ₃ (II) (wherein R ′ is a C _1-5 alkyl group, X is Cl, Br, OC
H ₃ or OC ₂ H ₅ ).
The fluorine-based coating composition described. 3. The inorganic pigment and / or thickening agent is 0.1.
The fluorine-based coating composition according to claim 1 or 2, which is surface-treated with about 20% by weight of the fluorine-containing silane compound.