JPH0347668B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paint solvent used during painting or paint manufacturing, and more particularly to an epoxy paint solvent suitably used in epoxy paints.

[Prior Art] Conventionally, volatile organic solvents such as thinner have often been used to dissolve paints such as oil-based paints, lacquer, and coal tar. Furthermore, toluene, Lutzker thinner, etc. are used as solvents for epoxy paints.

[Problems to be Solved by the Invention] However, these volatile organic solvents generally have a low flash point and may ignite or explode, and may also cause poisoning if inhaled by workers. In particular, toluene, radsker thinner, etc. are harmful to the human body, and poisoning from inhalation of these substances has been a serious problem for painting workers. Further, these conventional solvents can only be used in an amount of about 20% for oil-based paints or epoxy paints. In other words, if more of these solvents are added, the viscosity of the paint will drop and the coating properties will become very poor.
Therefore, a large amount of paint must be used, which is not economical.

The purpose of this invention is to solve the above-mentioned conventional problems, and to provide a paint solvent that is completely free from danger, does not reduce viscosity even when used in large amounts in paints, has excellent coating properties, and is inexpensive. do.

[Means for Solving the Problems] It has been known that when a caustic soda aqueous solution is mixed into an oil-based paint and stirred, the paint dissolves. However, when caustic soda is mixed in, it not only causes uneven viscosity but also discolors the paint, making it impractical as a solvent.
However, the present inventor noticed that a strong alkaline aqueous solution comparable to a caustic soda aqueous solution can be used as a solvent for oil-based paints, and as a result of intensive research, found that calcium ion water with an extremely high PH value can be used as a caustic soda aqueous solution. The present invention was completed based on the knowledge that the present invention similarly dissolves oil-based paints without causing discoloration of the oil-based paints.

That is, the paint solvent of the present invention dissolves a strong alkaline agent containing calcium oxide as a main component in seawater,
It contains a seawater treatment solution obtained by removing insoluble matter, preferably an aqueous solution (a) in which a strong alkaline agent containing calcium oxide as a main component is dissolved in water to near saturation, and seawater in a strong alkaline agent. It consists of a seawater treatment solution (b) treated with

Here, examples of strong alkaline agents containing calcium as a main component include calcium oxide and calcium hydroxide, and calcium oxide is preferably used in the present invention. Practically speaking, this calcium oxide is obtained by firing high-temperature calcium-containing natural products such as shells, bones, and limestone. By calcining these natural products at about 1350°C, products whose main component is calcium oxide can be obtained.

The ingredients of this baked product vary slightly, but
They are roughly as shown in Table 1. Table 1 is
This is based on an analysis by the Chiba Prefecture Pharmacists Association Inspection Center, but the values are based on 100g of sample for each ingredient.
It shows the weight inside.

Table 1 Phosphorus 78mg Calcium 68.6g Magnesium 145mg Potassium 8.4mg Iron 4.8mg Sodium 540mg A strong alkaline aqueous solution with a pH of about 13 can be obtained by dissolving 0.5% by weight of these calcined products in water.

This strong alkaline aqueous solution can be applied to oil-based paints, water-based paints,
When added in the same amount to twice as much to various paints such as lacquer and coal tar and stirred, the solution became homogeneous and fluid, with good coating properties. The paint solvent of the present invention has a high viscosity when added twice or more to the paint and has poor coating properties as it is, and is not practical for either brush or spray coating. By using a very small amount of about 0.5% of an organic solvent such as gasoline, the optimum viscosity for coating can be achieved.

Note that the amount of the strong alkaline aqueous solution to be added and the amount of thinner, etc. mixed in for viscosity adjustment will be selected depending on the coating situation.

By the way, the aqueous solution (a) of the strong alkaline agent containing calcium oxide as the main component explained above can be used for oil-based paints,
Although it showed excellent solubility and fluidity with paints such as water-based paints and lacquers, it had the disadvantage of causing unevenness with epoxy paints.

The inventor of the present invention has long focused on the various effects of ions in seawater, and as a result of repeated research into their effective use, the inventor discovered that a solution obtained by treating seawater with a strong alkaline agent can be used as a strong alkaline solution for various purposes. The heading has led to the present invention. That is, the present invention provides a paint solvent comprising an aqueous solution (a) of a strong alkaline agent containing calcium oxide as a main component and a solution (b) obtained by treating seawater with the strong alkaline agent.

Furthermore, the epoxy paint can be easily dissolved by dissolving about 0.5% of caustic soda (sodium hydroxide) in the total water-soluble (a).

Strong alkaline aqueous solution (a) is used as a strong alkaline agent for solution (b) in which seawater is treated with a strong alkaline agent.
Similar to the strong alkaline agent used in , calcined natural products containing high calcium content such as shells, bones, and limestone are used. Approximately 30 g of these calcined products are added to seawater, mixed and stirred, and then insoluble matter is removed to obtain a solution (b) with a pH of 13 or higher. By mixing the seawater treatment solution (b) obtained in this way and the strong alkaline aqueous solution (a) in a volume ratio of approximately 1:1, a paint solvent (c) is created.
get.

This paint solvent (c) exhibits strong alkalinity with a pH of 14 or higher, and can easily dissolve not only oil-based paints but also epoxy paints.

A paint solution with good coating properties can be obtained by using approximately the same amount of this paint solvent (c) for 1 part of the epoxy paint, but if a small amount of other solvents such as toluene and Lutzker thinner are used together , the viscosity can be adjusted, and in that case, about twice the amount of paint can be used. In either case, the instant drying properties are no different from those using only toluene, Lutzker thinner, etc.

Examples in which the paint solvent (c) of the present application is applied to oil-based paints, enamel-based paints, acrylic/urethane-based paints, and epoxy-based paints will be described below.

Examples 1 and 2 Synthetic resin paint Red (manufactured by Dainippon Toyo Co., Ltd.) was used as an oil-based paint, either as it was (undiluted solution) (Comparative Example 1) or diluted with 30% paint solvent (c) (implemented). Example 1) and stock solution with 30% paint solvent (c) and 4
% thinner (Example 2) was compared in terms of applicability, gloss, and adhesion. The results are shown in Table 1.

Table 1 Paintability Example 2 > Example 1 > Comparative Example 1 Gloss Example 2 > Example 1 > Comparative Example 1 Adhesion Example 2 > Example 1 > Comparative Example 1 As is clear from the table, the paint By using solvent (c), good results could be obtained in all items, and especially when a small amount of thinner was used in combination, excellent properties were shown.

Examples 3 and 4 Synthetic resin paint gray (manufactured by Asahipen) was used as an oil-based paint, the stock solution was diluted with 6% thinner (comparative example 2), 30% paint solvent (c) and 8
% thinner (Example 3) and 50% paint solvent (c) and 20% thinner (Example 4). compared. The results are shown in Table 2.

Table 2 Spreadability Example 4 = Example 3 >> Comparative Example 2 Gloss Example 4 > Example 3 >> Comparative Example 2 Adhesion Example 4 > Example 3 > Comparative Example 2 When only thinner was used, Both coatability and gloss were poor, but they were improved by using paint solvent (c).

Examples 5 and 6 As an oil-based paint, a quick-drying phthalic acid synthetic resin paint (trade name: Neo Alki Coat, Golden Yellow, manufactured by Kawakami Paints) was used, and the stock solution was diluted with 10% thinner (Comparative Example 3) , 30% paint solvent
Coatability of (c) and 10% thinner (Example 5) and 50% paint solvent (c) and 12% thinner (Example 6). The gloss and adhesion were compared. The results are shown in Table 3.

Table 3 Paintability Comparative Example 3>Example 6>Example 5 Gloss Example 6>Example 5>Comparative Example 3 Adhesion Example 6>Example 5>Comparative Example 3 As is clear from the table, the paint By using solvent (c), good results were obtained in all items other than coating properties, and especially when a small amount of thinner was used in combination, excellent properties were exhibited.

Examples 7 to 9 Platinite (manufactured by Kansai Paint) was used as the enamel paint, as it was (undiluted solution) (Comparative Example 4), and the undiluted solution was diluted with 10% paint solvent (c) (Example 7) , and the undiluted solution diluted with 30% paint solvent (c) (Example 8) and the undiluted solution diluted with 50% paint solvent (c) (Example 9). compared. The results are shown in Table 4.

Table 4 Spreadability Example 7>Comparative Example 4>Example 9>Example 8 Gloss Example 8>Example 7>Comparative Example 4>Example 9 Adhesiveness Example 9>Example 7=Example 8> Comparative Example 1 As is clear from the table, good results were obtained in all items by using paint solvent (c).

Examples 10, 11 Quick-drying macromer type acrylic/urethane resin paint (product name: NAX) as an acrylic/urethane paint
Using Superio, Red, Nippon Paint),
As is (undiluted solution) (Comparative Example 5), the undiluted solution diluted with 10% paint solvent (c) (Example 10), and the undiluted solution
The coating properties, gloss, and adhesion of a diluted coating using a combination of 10% paint solvent (c) and 2.5% Lutzker thinner (Example 11) were compared. The results are shown in Table 5.

Table 5 Paintability Comparative Example 5>Example 10>Example 11 Gloss Example 11>Example 10>Comparative Example 5 Adhesion Example 11>Example 10=Comparative Example 5 As is clear from the table, the paint Solvent (c) was superior to the original solution in both gloss and adhesiveness.

Examples 12 and 13 A two-component epoxy resin paint (product name Hypon 40 Overcoat, White, manufactured by Nippon Paint) was used as the epoxy paint, and 5% Lutzker thinner and 25% hardening agent were added to the stock solution (comparison). Example 6), the stock solution is 3
% Lutzker thinner (Comparative Example 7), the stock solution diluted with 30% paint solvent (c) and 20% Lutzker thinner (Example 12), and the stock solution diluted with 50% Lutzker thinner (Example 12). The paint solvent (c) was diluted with 20% Lutzker thinner (Example 13), and the coating properties, gloss, adhesion, and acid resistance were compared. In this case, the paint and paint solvent were forcibly mixed by mechanical stirring.
In addition, changes in acid resistance were observed when a releasable coating was applied to the film. The results are shown in Table 6.

Table 6 Coatability Example 12>Example 13>Comparative Example 7>Comparative Example 6 Gloss Example 12>Example 13>Comparative Example 7>Comparative Example 6 Adhesiveness Example 13>Example 12>Comparative Example 6> Comparative Example 7 Acid Resistance Example 13 > Example 12 > Comparative Example 6 > Comparative Example 7 Example 14 Using the trade name Epomarin, Black (manufactured by Kansai Paint) as an epoxy paint, the undiluted solution (Comparative Example 8) and the undiluted solution were used. Ratsker thinner 5% and hardener 20%
(Comparative Example 9), undiluted solution diluted with 4% lacquer thinner (comparative example 10), and undiluted solution diluted with 30% paint solvent (c) and 30% lacquer thinner. Regarding (Example 14), the coating properties, gloss, adhesiveness, and acid resistance were compared in the same manner as Examples 12 and 13. The results are shown in Table 7.

Table 7 Coatability Example 14 > Comparative Example 9 > Comparative Example 8 > Comparative Example 10 Gloss Example 14 > Comparative Example 9 > Comparative Example 10 > Comparative Example 8 Adhesiveness Example 14 > Comparative Example 9 > Comparative Example 10 > Comparative Example 8 Acid Resistance Example 14 > Comparative Example 9 > Comparative Example 10 > Comparative Example 8 Excellent results were obtained by using paint solvent (c) in combination in all items. In addition, when paint solvent (c) is used, it dries quickly, the amount of lacquer thinner used can be increased, resulting in a saving in the amount of paint, there is no strong odor as no curing agent is used, and the heat resistance after application is improved. We were able to obtain excellent results.

[Effects of the Invention] The solvent according to the present invention has no volatility because it is an aqueous solution of a strong alkaline agent containing calcium oxide as a main component. Therefore, it is not only harmless to the human body, but also has no risk of ignition or explosion.

Further, even if a large amount is added to the paint, the viscosity necessary for coating can be obtained. Therefore, it is possible to add a much larger amount than conventional solvents and save paint by that amount.

The solvent according to the present invention is very inexpensive because it uses shells, bones, limestone, etc. that can be obtained free or at low cost as raw materials.

Furthermore, since the solvent according to the present invention is strongly alkaline, it is possible to increase the alkalinity of the paint. Therefore, the alkalinity of the paint dissolved in this solvent increases, which increases the anti-oxidation effect of the paint film and increases its durability.

Furthermore, the solvent according to the present invention is non-toxic, has excellent coating properties and quick drying properties, and can be used as a substitute for epoxy paints that have hitherto had to rely on harmful solvents such as toluene and lacquer thinner.
It has extremely high practical value.

Claims (1)

[Claims] 1. A paint solvent for dissolving epoxy paints, etc., containing a seawater treatment solution obtained by dissolving a strong alkaline agent containing calcium oxide as a main component in seawater and removing insoluble matter. A paint solvent characterized by: 2. The paint solvent according to claim 1, wherein the strong alkaline agent is obtained by baking a calcium-containing natural product such as shell, bone, or limestone at high temperature.