JP2639579B2 - Method for manufacturing painted objects - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a coating product of a polyorganosiloxane-based coating in which the surface characteristics of a processing object such as a plastic or a metal are improved.

<Prior art> Plastics are lightweight, inexpensive, have excellent impact resistance and workability, and have properties such as not causing corrosion. In the industrial field, it is used in place of conventional metal materials or inorganic materials such as glass.

However, a molded article using the plastic has a defect that the surface is very easily damaged and the solvent resistance is inferior to that of an inorganic material.

Therefore, in order to solve the above drawback, the most commonly used method is a method of performing a surface treatment with a surface coating composition such as an organic, silicon, or inorganic material. In addition, it is used for a metal material such as aluminum whose surface is easily damaged. Further, in the above method, the surface coating composition is applied to an object to be treated such as plastic or metal and cured by, for example, an oven heat treatment or an ultraviolet treatment. At present, heat treatment is performed.

However, when using the oven heat treatment,
The curing time becomes very long, causing problems in industrial productivity. Therefore, in order to shorten the curing time, the amount of the curing catalyst used is increased, and a solution containing the curing catalyst and / or the curing agent and a solution containing the surface coating composition are made into a two-part type, and mixed before use. And other methods have been proposed.
Certainly, in this method, although the curing time of the surface coating composition is shortened, there is a problem in storage of the solution itself containing the surface coating composition, and the solution cannot be used for a long period of time. Occurs.

<Problems to be Solved by the Invention> An object of the present invention is to provide a polyorganosiloxane-based coating having excellent surface strength and wettability, and capable of significantly shortening the curing time compared to conventional oven heat treatment. An object of the present invention is to provide a method for manufacturing a product.

<Means for Solving the Problems> According to the present invention, an object to be treated coated with the polyorganosiloxane-based coating composition is at 30 ° C or higher,
A method for producing a coated article is provided, wherein the article is immersed in a liquid heated below the heat-resistant temperature of the article to be treated to cure the polyorganosiloxane composition.

 Hereinafter, the present invention will be described in more detail.

In the production method of the present invention, first, a polyorganosiloxane-based coating composition is applied to the inside of the object to be treated. The polyorganosiloxane-based coating composition contains a silanol group and / or an alkoxy group, and contains a polyorganosiloxane selected from one or more of a group consisting of a chain, a ring, and a network. There is no particular limitation, for example, CH ₃ Si (OCH ₃ ) ₃ , CH ₃ Si (OC
_{2 H 5) 3, Si (} OC 2 H 5) 4, Si (OC 4 H 9) 4, HSCH 2 CH 2 CH 2 Si (OC
H ₃ ) One or more of the group consisting of silane coupling agents such as ₃ ; colloidal silica; sodium silicate No. 3, silicates such as lithium silicate; and alkyl silicates such as ethyl silicate and methyl silicate. Selected from organosiloxanes and / or their hydrolytic condensates or trade names "Silvue 101", "Silvue 100"
(Manufactured by SDC), trade name "X-12-2206", "KP-1100"
(Manufactured by Shin-Etsu Chemical Co., Ltd.)
0 ”,“ Tosguard 520 ”(manufactured by Toshiba Silicone Co., Ltd.)
And other commercially available products. Further, a modified substance selected from one or more of the group consisting of an acrylic silicon modified substance, an epoxy silicon modified substance, a melamine silicon modified substance, a urethane silicon modified substance, and the like can be used.

The object to be processed may be any of plastic or metal, and specifically, for example, polymethyl methacrylate,
Preferable examples include polycarbonate, polyethylene terephthalate, polystyrene, ABS resin, acrylic styrene, unsaturated polyester, acrylic ethylene styrene, polybutylene terephthalate, aluminum, brass, and bronze.

In order to apply the polyorganosiloxane-based coating composition to the object to be treated, the polyorganosiloxane-based coating composition may be applied to, for example, an alcohol-based solvent such as methanol, ethanol, isopropanol, or butanol, or diethylene glycol monoethylene acetate. Can be applied by adding and mixing a solvent such as a compound having two or more functional groups, and then performing brush coating, dip coating, spin coating, spray coating, flow coating, roller coating, or the like. The object to which the polyorganosiloxane-based coating composition has been applied can be used as it is in the next curing treatment step, but the solvent in the polyorganosiloxane-based coating composition is scattered, and the polyorganosiloxane-based coating composition is dispersed. It is preferable to carry out preliminary heat treatment for a short time in order to strengthen the adhesion between the object and the object to be treated and to partially cure the film. The preheating treatment is preferably performed at a temperature of 30 ° C. or higher and a heat-resistant temperature of the object to be processed or lower, preferably 80 to 120 ° C. At this time, if the temperature is lower than 30 ° C., the film is not partially cured, and if the temperature exceeds the heat resistant temperature of the object, the object itself may be deformed, which is not preferable. The preliminary heat treatment can be performed by a conventional oven heat treatment or the like.

In the production method of the present invention, the article to be treated coated with the polyorganosiloxane-based coating composition is immersed in a liquid heated to 30 ° C. or higher and a heat-resistant temperature of the article to be treated or lower. The polyorganosiloxane-based coating composition can be cured. The curing by the immersion can efficiently transfer heat to the surface of the object to be treated, as compared with the conventional oven heat treatment, and can hydrolyze alkoxy groups and hydroxyl groups in the polyorganosiloxane-based coating composition. Can accelerate the dehydration-condensation reaction, so that the curing treatment of the polyorganosiloxane-based coating composition can be performed in a short time. When the temperature of the liquid is lower than 30 ° C., the film is not cured, and when the temperature is higher than the heat-resistant temperature of the object,
The object to be processed itself is not preferable because it causes thermal deformation. If the heat-resistant temperature of the object to be treated is higher than the boiling point of the liquid, the object is subjected to a high pressure, which causes a problem in industrial productivity. At this time, the curing time by immersion is usually 10 to 60 minutes. The liquid is not particularly limited as long as the liquid does not dissolve the polyorganosiloxane-based coating composition and has a boiling point of more than 30 ° C., for example, water, methanol, ethanol, cellosolve acetate, ethyl acetate, xylene, Trichloroethane, cyclohexane and the like can be preferably mentioned, and a liquid having polarity is more preferable.

In order to further shorten the curing time, it is also possible to add one or more curing catalysts to the liquid, and furthermore, a plurality of curing catalysts each containing one or more different curing catalysts. By immersing the object coated with the polyorganosiloxane-based coating composition in a liquid in multiple stages, particularly preferably in two stages, the wettability and the like can also be improved. As the curing catalyst,
For example, sodium acetate, sodium oxalate, sodium citrate, dimethylamine acetate, ethanolamine acetate, dimethylaniline formate, tetraethylammonium benzoate, sodium carboxylate, sodium carboxylate such as sodium formate, sodium silicate, lithium silicate, etc. It is preferably selected from one or more members selected from the group consisting of silicates, alkali metal hydroxides such as sodium hydroxide, nitrites, amino acid sodium thiocyanate and amino acid salts. The amount of the curing catalyst used varies depending on the desired curing conditions, but is 0 to 5 parts by weight based on 100 parts by weight of the liquid.
It is preferably in the range of 0 parts by weight, and if it exceeds 50 parts by weight, the appearance of the coated product deteriorates because a large amount of the curing catalyst remains in the coated product, and the curing catalyst is added to the organosiloxane-based coating composition liquid. It is not preferable because it may be mixed. The immersion-cured polyorganosiloxane-based coating product is preferably taken out of the liquid, washed, drained, and dried. The drying process can be performed by heating.

<Effect of the Invention> In the production method of the present invention, the object to be treated coated with the polyorganosiloxane-based coating composition is immersed and cured in a heated liquid, so that the curing treatment can be performed in a short time, And improve the surface strength of the object,
Further, since the wettability and the like can be improved, it is industrially very useful. Especially effective for painted materials such as plastics which are used in place of inorganic materials and metals recently.
For example, automotive parts such as meter covers, lamp covers, center pillars, moldings, wheels, optical lenses,
It is expected to be used for transparent articles.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The test methods and evaluation criteria used in the examples are shown below.

(1) Abrasion resistance test i) Steel wool test Scratch tester (manufactured by KT Corporation) to scratch the surface of the coating film of polyorganosiloxane coating
Was rubbed 30 times with steel wool # 0000 under a load condition of 500 g to examine the degree of scratching. The evaluation criteria are as follows.

5. No scratches. 4. Only slight scratches are made.

3. Slightly scratched. 2. A large number of spots are seen.

1 .. It is extremely scratched and damaged.

ii) Taber abrasion test Load is applied using a Taber abrasion tester (manufactured by Toyo Seiki Seisaku-sho).
The haze meter (manufactured by Suga Test Instruments Co., Ltd.) was measured after 500 g of the worn wheel CS-10F was rotated 500 times.

(2) Adhesion test The coated polyorganosiloxane coating was immersed in warm water heated to 80 ° C for 24 hours, and the adhesion of the polyorganosiloxane coating composition was examined.

(3) Wettability test After the polyorganosiloxane-based coating product was left in running water for 24 hours, the repelling state of the water on the surface 5 to 10 seconds after removal was visually observed. The evaluation criteria are as follows.

A: all wet B: not partially wet C: not wet (4) Pencil hardness test A pencil hardness test was performed in the same manner as described in JIS K5400.

(5) Gobang test (adhesiveness) The test was performed in the same manner as described in JIS K5400.

Example 1 After dip-coating the product name “Siliview 101” (manufactured by SDC) on the entire surface of a 0.3 × 15 × 15 cm polymethyl methacrylate plate, using a clean oven (manufactured by Sanki Keiso Co., Ltd.) for 20 minutes Preheating treatment was performed in an oven at 85 ° C. to evaporate the solvent. Next, to 85 parts by weight of warm water heated to 85 ° C,
The polymethyl methacrylate plate in which the solvent was dispersed was immersed in a solution containing 15 parts by weight of sodium acetate for 15 minutes to cure the “Silview 101” (manufactured by SDC). Next, the coated polymethyl methacrylate plate was taken out of the warm water, washed with water for 5 minutes, and then subjected to the abrasion resistance test, the adhesion (warm water and goban) test, and the pencil hardness test. Table 1 shows the results.

Examples 2 to 4 The preheating time in Example 1 was set to 20 minutes and 30 minutes, respectively.
And 30 minutes, and the tests were performed in the same manner as in Example 1 except that the immersion curing times were changed to 30 minutes, 15 minutes and 30 minutes, respectively.
Table 1 shows the results.

Comparative Examples 1 to 3 In the same manner as in Example 1, except that the curing of the product name “Silview 101” (manufactured by SDC) was performed only by oven heat treatment for 4 hours, 1 hour, and 30 minutes, respectively. A methyl methacrylate plate coating was prepared and subjected to the same test. Table 1 shows the results.

Examples 5 to 10 Polymethyl methacrylate coated articles were obtained in the same manner as in Example 1 except that the polyorganosiloxane-based coating composition, curing catalyst and reaction conditions shown in Table 2 were changed. After the obtained coating was washed with water for 5 minutes, it was heated and dried in an oven at 80 ° C. for 5 minutes. Next, the obtained coated product was subjected to a wear resistance test and an adhesion (goban) test. Table 2 shows the results.

Comparative Examples 4 to 9 As shown in Table 2, a polymethyl methacrylate plate-coated product was manufactured in the same manner as in Example 5 except that curing was performed only by oven heating treatment without performing immersion curing, and each test was performed. Table 2 shows the results.

Example 11 Instead of sodium acetate, a polymethyl methacrylate plate coated product was obtained in the same manner as in Example 1 except that a 1: 1 mixture of sodium acetate and sodium silicate was used, and the immersion curing time was 30 minutes. . After the obtained coated product was washed with water for 5 minutes, it was dried in an oven at 85 ° C. for 5 minutes. Next, the obtained coated article was subjected to a wear resistance test, an adhesion (goban) test and a wettability test. Table 3 shows the results.

Example 12 After dip-coating the product name “Silview 101” (manufactured by SDC) on the entire surface of a 0.3 × 15 × 15 cm polymethyl methacrylate plate, using a clean oven (manufactured by Sanki Keiso Co., Ltd.)
Preheating treatment was performed in an oven at 85 ° C. for 20 minutes to disperse the solvent. Next, as a first step, 15 parts by weight of sodium acetate was added to 85 parts by weight of warm water heated to 85 ° C., and then the polymethyl methacrylate plate in which the solvent was dispersed was immersed for 15 minutes. Next, the polymethyl methacrylate plate is taken out of the hot water containing sodium acetate, and as a second step,
No. 3 sodium silicate 10 in 90 parts by weight of warm water heated to 85 ° C
The “Silview 101” (manufactured by SDC) was cured by immersion in warm water to which parts by weight had been added for 15 minutes. Then take out the polymethyl methacrylate plate coating from the warm water,
Washing with water for 5 minutes and oven drying at 85 ° C. for 5 minutes were performed. The resulting coated article was subjected to a wear resistance test, an adhesion (goban) test and a wettability test. Table 3 shows the results.
Shown in

Examples 13 and 14 A polymethyl methacrylate plate coating was produced in the same manner as in Example 12 except that the curing agent in the second stage was changed as shown in Table 3, and each test was conducted. Table 3 shows the results.

Comparative Examples 10 and 11 As shown in Table 3, a polymethyl methacrylate plate coated article was produced in the same manner as in Example 11 except that curing was performed only by oven heating without immersion curing, and each test was performed. Was. Table 3 shows the results.

From the above results, the polyorganosiloxane-based coating product obtained by the production method of the present invention can obtain the same surface properties in about 1/2 to 1/4 of the curing time of the conventional oven heat treatment. In addition, it was found that excellent wettability can be imparted as compared with conventional oven heat treatment.

Claims (4)

(57) [Claims] An object to be treated coated with a polyorganosiloxane-based coating composition is immersed in a liquid heated to 30 ° C. or higher and below the heat-resistant temperature of the object to be treated, and A method for producing a coated article, comprising curing a system composition. 2. The method according to claim 1, wherein said liquid contains a curing catalyst. 3. The method according to claim 1, wherein the curing of the polyorganosiloxane-based coating composition is immersed in a plurality of liquids each containing a different curing catalyst. 4. An object to be treated coated with the polyorganosiloxane-based coating composition is preheated to a temperature of 30 ° C. or higher and a temperature not higher than the heat-resistant temperature of the object to be treated. The method according to any one of claims 1 to 3, wherein the solvent in the composition is dispersed.