JPH064811B2 - Post coat paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is mainly used for coating metal plates such as zinc-iron plates, aluminum-zinc alloy-plated steel plates, and aluminum plates, and posts used for structural steel such as bridges. It relates to coat paint.

[Prior Art] Fluororesin-based paints using polyvinylidene fluoride or the like as a base resin have excellent physical and chemical properties,
That is, since it has excellent weather resistance, chemical resistance, stain resistance, heat resistance, etc., it can be coated on a metal plate such as a galvanized steel plate or an aluminum plate to provide a coated metal plate with excellent durability. Used in building materials such as.

However, the problem with such a fluororesin-coated metal sheet is that the fluororesin-based paint coating film tends to be scratched by frictional impact or scratching during transportation, transportation in a coating plant, or handling at a construction site. Is. There are cases where this scratch is shallow only on the surface of the coating film and deep where it reaches the metal surface.However, if the surface of the coating film is scratched, it must be repaired with a room temperature dry type repair paint, which requires a great deal of cost and days. In the case of deep scratches reaching the metal surface, it is also necessary to apply an anticorrosive paint. Moreover, the repaired portion is inferior in weather resistance, corrosion resistance, chemical resistance, durability, etc. to a normal coating film. Therefore, a fluororesin-based coating material having excellent scratch resistance is desired.

On the other hand, in the case of precoat paint, in order to improve the scratch resistance of the paint film, Japanese Patent Publication No. 50-25485, "Precoat Steel Sheet", Japanese Patent Publication No. 51-8128, "Paint for precoated steel sheet containing glass flakes", the present application JP-A-6 by a person
No. 1-237636 "Painted Steel Sheet" and Japanese Patent Publication Sho 63-2
As disclosed in Japanese Patent No. 991, "Paint for Metal Plates", etc., a coating film can be obtained by adding E-glass or C-glass in the form of fibers, flakes or beads to the top-coating paint applied to the metal plate. Attempts have been made to improve the wear resistance and scratch resistance of the.

When glass fibers or the like are added to the paint as described above, the surface of the glass fibers is treated in order to improve the wettability between the glass fibers and the resin of the paint. For example, in the case of a general polyester resin coating, the surface of glass fiber is treated with a silane coupling agent and added to the polyester resin coating. Improve the wettability of glass fiber and polyester resin with a silane coupling agent to evenly disperse the glass fiber in the coating film of the paint and effectively improve the abrasion resistance and scratch resistance of the coating film by the glass fiber. It is possible to improve water resistance, moisture resistance, gas permeation resistance and the like.

However, in the case of a fluororesin type coating, sufficient wettability cannot be obtained even if the surface treatment of the glass fiber is simply performed by using a silane coupling agent. To this end, the applicant of the present invention, "Painted steel plate" in JP-A-61-237636 and "Paint for metal plate" in JP-B-63-2991.
Attempts have been made to improve the wettability of glass fibers to fluororesin-based coatings by first surface treating the glass fibers with a titanate-based coupling agent and then with a silane-based coupling agent as provided in US Pat. Therefore, it is possible to uniformly disperse glass fibers in a fluororesin-based paint to increase the strength and hardness of the coating film, thereby improving the abrasion resistance and scratch resistance of the coating film.

[Problems to be Solved by the Invention] However, even when the glass fiber is surface-treated with a titanate coupling agent and then surface-treated with a silane coupling agent as described above and added to the fluororesin coating, At this time, there is a problem in that the glass fiber causes sedimentation, and the sedimented glass fiber is hard and hard so that redispersion becomes difficult. In particular, Japanese Patent Application Laid-Open No. 61-237636 “Painted Steel Sheet” and Japanese Patent Publication No. 63-
The fluororesin-based paint provided in the "paint for metal plate" of Japanese Patent No. 2991 is used for precoating, and the viscosity of the paint is adjusted to be relatively high because the coating is mainly performed by a roll coater. When used as a coating material for coating, the viscosity of the coating material is generally adjusted to be relatively low because it is generally applied by spraying. If the viscosity of the coating material is low, the sedimentation rate of glass fibers will be remarkably high. . Therefore, in this case, the content of glass fiber in the coating film applied first in the coating process and the content of glass fiber in the coating film applied last will be different. As a result, the content of glass fiber in the coating film decreases and coating unevenness occurs.

The present invention has been made in view of the above points, and it is possible to add glass fibers to the fluororesin-based coating material with good wettability and prevent the precipitation of glass fibers from occurring. The purpose is to provide a post-coat paint.

[Means for Solving the Problem] However, the post-coat paint according to the present invention comprises a glass fiber surface-treated with a titanate-based coupling agent and subsequently surface-treated with a silane-based coupling agent, and a plasticizer. In the present invention, the surface treatment of the glass fiber with a titanate-based coupling agent and a silane-based coupling agent provides a fluorine resin. Improves the wettability of the glass fiber to the resin-based paint, and further improves the thixotropy of the paint by blending a plasticizer so that the glass fiber can be prevented from settling even if the paint has a low viscosity. It is a thing.

The present invention will be described in detail below.

The treatment of glass fiber is performed by using a titanate coupling agent and a silane coupling agent together, and the chemical structural formula of the silane coupling agent is CH ₂ = CHSi.
Vinyl type typified by (OCH ₃ ) ₃ , Epoxy type typified by The methacryloxy type typified by, the mercapto type typified by HSC ₃ H ₆ Si (OCH ₃ ) ₃ and other chloropropyl type typified can be used.

Further, as the titanate coupling agent, the chemical structural formula is Of isopropoxy type represented by Oxyacetic acid type represented by The ethylene glycol type typified by, and other coordinate type types can be used.

In performing the surface treatment of the glass fiber with these coupling agents, the surface treatment of the glass fiber is first performed with the titanate coupling agent. The treatment with the titanate coupling agent as the first step is carried out as follows. First, a ketone-based solvent, an ester-based solvent, a hydrocarbon-based solvent, an alcohol-based solvent, or an ether-based solvent is used.
0.01 parts by weight of titanate coupling agent to parts by weight.
Add ~ 20 parts by weight and stir. Then, 1 to 60 parts by weight of glass fiber is further added to 100 parts by weight of the solvent containing the titanate coupling agent and stirred. This stirring is preferably carried out by rotating the stirring blade at a rotation speed of 1200 to 1500 rpm and at a temperature of 30 to 50 ° C. for a time of 5 to 30 minutes.

After the surface treatment with the titanate coupling agent, the glass fiber is surface treated with the silane coupling agent. The treatment with the silane coupling agent as the second step is performed by adding 0.01 to 10 parts by weight of the silane coupling agent to 100 parts by weight of the mixture of the solvent containing the titanate coupling agent and the glass fiber. It is performed by stirring. The stirring speed is 1
200 to 1500 rpm, temperature 20-40 ° C, time 10
It is preferable to carry out under the condition of ~ 30 minutes.

In this way, the glass fiber is surface-treated with a titanate-based coupling agent and then with a silane-based coupling agent, and then the compositely surface-treated glass fiber and a plasticizer are added to a fluororesin-based coating composition. To do.

As the plasticizer used in the present invention, dibutyl tartrate, dibutyl succinate, dicyclohexyl adipate, dimethyl phthalate, dibasic acid esters such as dibutyl phthalate, fatty acid esters such as butyl stearate, amyl benzoate, benzoic acid. Examples thereof include benzoic acid esters such as benzyl acid ester, triphenyl phosphate, phosphoric acid esters such as tributyl phosphate, triacetin, glycerin esters such as castor oil, and these may be used alone or in combination of two or more. You may mix and use it. Among these plasticizers, dibasic acid ester-based plasticizers have the greatest effect of suppressing the precipitation of glass fibers, followed by fatty acid ester-based plasticizers butyl stearate and benzoic acid ester-based plasticizers. Benzyl can give good results. The effect of phosphoric acid esters, glycerin esters, and other amino compounds is not great. The paint for precoat has a viscosity of 100 to 200 seconds (Ford
In contrast to the coating run-off time at 25 ° C. in Cup # 4, the viscosity of the post-coating coating composition of the present invention is as low as 20 to 60 seconds. In order to impart thixotropy to the above coating composition, when a dibasic acid ester plasticizer is used as a plasticizer, the addition amount is 3 parts by weight or more, more preferably 5 parts by weight, based on 100 parts by weight of the fluororesin coating material. It is desirable to set more than one copy. If the amount added is less than 3 parts by weight, the thixotropy of the coating is insufficient, and it is difficult to suppress the sedimentation of glass fibers during storage. The upper limit of the amount added is 35 parts by weight, more preferably 30 parts by weight. If the amount added exceeds 35 parts by weight, the weather resistance of the coating film tends to deteriorate, which is not preferable. When the plasticizer is added to the fluororesin-based paint, the stirring speed is 1200 to 1500 rpm and the temperature is 2
It is preferable to set the conditions of 0 to 40 ° C. and stirring time of 10 to 30 minutes. When the temperature is 20 ° C. or lower, the effect of imparting thixotropy is small, and the effect of suppressing the sedimentation of glass fibers may not be sufficiently obtained. Further, if the temperature is 40 ° C. or higher, fusion of the fluororesin may occur, which is not suitable.

As the fluororesin-based paint, vinylidene fluoride paint or vinyl fluoride paint can be used, and is composed of a fluororesin, a pigment, a solvent and the like. The compounding amount of the above-mentioned compositely surface-treated glass fiber in the fluororesin coating is preferably set to 1 to 60 parts by weight with respect to 100 parts by weight of the coating. If the blending amount is less than 1 part by weight, the effects of abrasion resistance and scratch resistance due to the improvement of the hardness of the coating film due to the blending of glass fiber cannot be sufficiently obtained, and 60
If the amount is more than parts by weight, the denseness of the coating film tends to decrease, and the water resistance and corrosion resistance tend to deteriorate. The glass fiber preferably has a diameter of 1 to 30 μm and a fiber length of 1 to 200 μm. When the diameter of the glass fiber exceeds 30 μ, the stability of the glass fiber in the fluororesin-based paint is poor, and it becomes difficult to suppress the precipitation of the glass fiber. Further, if the fiber length exceeds 200 μ, it becomes difficult to uniformly disperse the glass fiber in the paint, and when spray coating, the discharge port of the spray gun may be clogged.

As described above, the post-coat paint according to the present invention can be prepared by adding and mixing the glass fiber and the plasticizer to the fluororesin-based paint, and the zinc iron plate, aluminum-zinc alloy. Used for post-coating on metal plates such as plated steel plates and aluminum plates and structural steel. At this time, it is preferable to apply an undercoat paint such as an epoxy-based paint on the surface of the metal plate to a thickness of about 5 μm, dry it, and apply it on this. As the coating method, air spray, airless spray, electrostatic coating, brush coating, hand roller coating and the like are mainly applied. The post-coat paint according to the present invention is thus mainly used as a paint for metal plates, but is not limited to metal plates and is used as a post-coat paint for concrete, roof tiles, tiles, ceramic products, wood materials, and glass materials. You can also

The invention will now be illustrated by the examples.

Example 1 A zinc-plated steel sheet of JIS standard Z27 having a thickness of 1.6 mm was subjected to a zinc phosphate chemical conversion treatment, and further as an undercoat paint, an epoxy resin paint (FS-0 manufactured by Dainippon Ink and Chemicals, Inc.).
1P) was air-spray coated so that the dry coating film thickness would be 5μ, and baked and dried under conditions of a maximum temperature of 180 ° C. for 10 minutes.

On the other hand, methyl ethyl ketone and butyl cellosolve were mixed with 50
5 parts by weight of an isopropoxy type titanate coupling agent was added to 100 parts by weight of a mixed solvent mixed at a ratio of 50, and the mixture was stirred. Next, to 100 parts by weight of the solvent containing the titanate coupling agent, 50 parts by weight of glass fiber having a fiber diameter of 13 μm and a fiber length of 20 to 50 μm was added and stirred. This agitation is performed with a rotating speed of the stirring blade of 12
It was carried out under the conditions of 00 rpm, temperature 30 ° C. and stirring time 15 minutes. After the treatment with the titanate coupling agent in this way, 2 parts by weight of a vinyl type silane coupling agent was added to 100 parts by weight of the mixture of the solvent containing the titanate coupling agent and the glass fiber and stirred. did. This stirring was performed under the conditions of a rotation speed of 1200 rpm, a temperature of 30 ° C., and a stirring time of 15 minutes. In this way, a glass fiber was obtained which was subjected to a composite treatment of the surface treatment with the titanate coupling agent and the treatment with the silane coupling agent.

Next, 10 parts by weight of dimethyl phthalate, which is a dibasic acid ester plasticizer, was added to 100 parts by weight of a fluororesin-based paint (Fluoropon SF-18) manufactured by Dainippon Ink and Chemicals, Inc., and stirred. Rotation speed is 1200 rpm, temperature is 30
It was carried out under the conditions of ℃ and stirring time of 20 minutes. Next, 20 parts by weight of the glass fiber treated as described above was added to 100 parts by weight of this coating material and stirred. 1200 rpm for stirring
It was carried out under the conditions of rpm, temperature 30 ° C. and stirring time 20 minutes.
In this way, a glass fiber-containing fluororesin-based coating material (Fluoropon SGF-18) was prepared.

The glass fiber-containing post-coating fluororesin-based coating material (Fluoropon SGF-18) prepared in this manner was used as the above-mentioned FS.
-01P undercoated galvanized steel sheet is coated with air spray as a top coating so that the thickness of the dried coating film is 30μ, and dried at a maximum plate temperature of 240 ° C and a baking time of 20 minutes to obtain a coated galvanized steel sheet. Got

Example 2 In Example 1, the compounding amount of dimethyl phthalate, which is a dibasic acid ester plasticizer, with respect to the fluororesin-based paint (Fluoropon SF-18) manufactured by Dainippon Ink and Chemicals, Inc. was set to 3 parts by weight. A fluororesin-based paint for glass fiber-containing postcoat was prepared in the same manner as in Example 1 except that the above was applied, and a coated galvanized steel sheet was obtained in the same manner as in Example 1.

Example 3 In Example 1, the compounding amount of dimethyl phthalate, which is a dibasic acid ester plasticizer, with respect to the fluororesin-based paint (Fluoropon SF-18) manufactured by Dainippon Ink and Chemicals, Inc. was set to 35 parts by weight. A fluororesin-based paint for glass fiber-containing postcoat was prepared in the same manner as in Example 1 except that the above was applied, and a coated galvanized steel sheet was obtained in the same manner as in Example 1.

Example 4 In Example 1, instead of dimethyl phthalate, which is a dibasic acid ester plasticizer, for the fluororesin-based paint (Fluoropon SF-18) manufactured by Dainippon Ink and Chemicals, Inc., a fatty acid ester plasticizer was used. Except that 10 parts by weight of butyl stearate was added to prepare a fluororesin-based coating material for glass fiber-containing post coat in the same manner as in Example 1 and prepared a galvanized steel sheet in the same manner as in Example 1. Obtained.

Comparative Example 1 Fluororesin-based paint (Fluoropon SF-1 manufactured by Dainippon Ink and Chemicals, Inc., which does not contain glass fiber and a plasticizer.
A coated galvanized steel sheet was obtained in the same manner as in Example 1 except that 8) was used.

Comparative Example 2 A coating material was prepared in the same manner as in Example 1 except that the plasticizer was not added, and a coated galvanized steel sheet was obtained in the same manner as in Example 1.

Comparative Example 3 In Example 1, instead of using glass fibers which were compositely surface-treated with a titanate-based coupling agent and a silane-based coupling agent, non-surface-treated glass fibers were used. Prepare the paint as in 1.
A coated galvanized steel sheet was obtained in the same manner as in Example 1.

Comparative Example 4 In Example 1, except that glass fibers having a surface treated in combination with a titanate coupling agent and a silane coupling agent were used instead of glass fibers that had not been surface treated, and that no plasticizer was further added. A coating material was prepared in the same manner as in Example 1, and a coated galvanized steel sheet was obtained in the same manner as in Example 1.

For each of the above Examples and Comparative Examples, the storage stability of the post-coat paint and the performance of the coating film of the coated galvanized steel sheet were measured. The results are shown in the table below. In the following table, "storage stability" means that the viscosity of the paint is 40 seconds (Ford cup # 4, 2
(Outflow time at 5 ° C.), put this into a glass paint settling tube to a height of 15 cm, and measure the settling depth of the glass fiber after 10 days, 30 days, and 50 days, respectively, and measure the glass fiber in the paint. The sedimentation rate was calculated from the blended amount, and the sedimentation rate was expressed in%. In addition, "thixotropy" is the same as No. B type viscometer rotor. No. 2 was used, the viscosity was measured at the rotation speeds of the rotor of 60 rpm and 12 rpm, and the thixotropy index was obtained by the following formula to evaluate.

(D ₁ and D ₂ are shift speeds (rpm) at each rotation speed,
Y ₁ and Y ₂ are viscosities (cp corresponding to D ₁ and D ₂ respectively)
s)) Furthermore, the "pencil hardness" in "scratch resistance" is JI
The test was conducted based on SD-0202. "Sutherland" in "Scratch resistance" is JIS K-5701
In accordance with the abrasion resistance test of No. 1, the coated steel sheet coated with the back surface coating was used instead of the friction paper, and the test was conducted at 50 times of friction rotation. There are 5 changes in the surface, 4 changes in the friction surface slightly, 4 changes in the friction surface to some degree, 3 changes in the friction surface are 2 changes in the friction surface, 2 changes in the friction surface Some were labeled as 1. "Coin scratch" in "Scratch resistance" is 4 yen with 10 yen coin on the surface of the coating film.
The test is conducted by scratching at an angle of 5 degrees, and the degree of scratches on the coating film is evaluated on a scale of 5; 5 if the undercoating film has not been reached and 4 if it reaches 10%. , 70% when reaching 30% undercoat
% When the undercoat coating film was reached, and 1 when the 100% undercoat coating film was reached. The "Taber wear resistance" in the "scratch resistance" is based on JIS K-6902, the wear wheel is set to CS-17, the wear count is set to 1000 times, the load is set to 1 kg, and the test is performed to reduce the wear loss. g
It was converted to / m ² and evaluated. “Chemical resistance” means that the cut surface of the test piece is sealed so that the chemicals shown in the table do not penetrate, and the test piece is immersed in the chemicals of the concentration shown in the table at a temperature of 25 ° C. for 15 minutes.
A 0-hour test was performed, and the presence or absence of blistering on the coating film was evaluated. If no blistering occurred, ○, blistering was 3
The case of 0 to 70% is shown by Δ, and the case of occurrence of blistering is 70% or more is shown by x. "Accelerated weathering resistance" refers to JIS A-47.
Based on No. 06, a test was performed with a sunshine weather meter to measure the discoloration (ΔE) and the gloss retention rate of the coating film surface after a test time of 5000 hours. Furthermore, "corrosion resistance, salt spray test" is JIS Z-2371, JIS K-5.
Based on 400, the test is performed for 2000 hours, and when there is no blistering, it is ○, and blistering is 30 to 50%.
The case was evaluated as Δ, and the case where the occurrence of blisters was 70% or more was evaluated as x, and the width of penetration of the blisters into the coating film was expressed in mm.

As a result of the above table, Comparative Example 3 in which the glass of each example has a higher hardness and excellent scratch resistance than the glass of Comparative Example 1 in which no glass fiber is compounded, and the glass fiber which is not surface-treated is compounded, It is confirmed that the corrosion resistance is superior to that of Comparative Example 4. In addition, it is confirmed that the glass fibers of each Example are excellent in storage stability of the glass fiber in the low viscosity region of the coating material. From the comparison with Comparative Examples 2 and 3, the storage stability depends on the effect of the plasticizer. It is considered that the effect of the surface treatment with the titanate coupling agent and the silane coupling agent on the glass fiber is synergistic. As shown in Example 2, it is difficult to obtain sufficient effects when the amount of the plasticizer is 3 parts by weight, and when the amount of the plasticizer is 35 parts by weight as shown in Example 3, the coating film is Weather resistance tends to deteriorate. Therefore, it is confirmed that the compounding amount of the plasticizer is more preferably about 5 to 30 parts by weight. Further, when a fatty acid ester as used in Example 4 is used instead of the dibasic acid ester as in Example 1 as the plasticizer, the storage stability tends to be inferior. It is confirmed that it is more preferable to use dibasic acid esters.

[Effects of the Invention] As described above, in the present invention, a glass fiber and a plasticizer, which are surface-treated with a titanate coupling agent and subsequently surface-treated with a silane coupling agent, are used as a fluororesin coating material. Since it is compounded, it is possible to improve the wettability between the glass fiber and the paint by this composite coupling agent treatment, and to improve scratch resistance and abrasion resistance by improving the corrosion resistance and the hardness of the coating film by the glass fiber. At the same time, the plasticizer imparts thixotropy to the coating material to prevent the glass fibers from settling, thereby enhancing the storage stability.

Claims (5)

[Claims] 1. A glass fiber, which comprises a fluororesin coating material and a glass fiber, which is surface-treated with a titanate coupling agent and subsequently surface-treated with a silane coupling agent, and a plasticizer. Fluorine resin paint 1
1 to 60 parts by weight with respect to 00 parts by weight, and the amount of the plasticizer compounded is 3 to 100 parts by weight of the fluororesin coating material.
Post-coat paint characterized by being 35 parts by weight. 2. The post-coat paint according to claim 1, wherein the glass fiber has a diameter of 1 to 30 μm and a fiber length of 1 to 200 μm. 3. The plasticizers are dibutyl tartrate, dibutyl succinate, dicyclohexyl adipate, dimethyl phthalate, dibasic acid esters such as dibutyl phthalate, fatty acid esters such as butyl stearate, amyl benzoate, It is selected from benzoic acid esters such as benzyl benzoate, triphenyl phosphate, phosphoric acid esters such as tributyl phosphate, triacetin, and glycerin esters such as castor oil, and the compounding amount is 100% by weight of the fluororesin-based paint. The post-coat paint according to claim 1 or 2, which is 5 to 30 parts by weight with respect to parts by weight. 4. The post-coat paint according to claim 1, wherein the fluororesin-based paint is a vinylidene fluoride-based paint. 5. The post coat according to any one of claims 1 to 4, which is applied to any one of air spray, airless spray, electrostatic coating, brush coating, and hand roller coating methods. paint.