JP2017226763A - Water-based paint for ferrous material and dry paint film solubilizer for water-based paint thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based paint and a dry paint film solubilizer firmly stuck to a steel material in a wide temperature range of ordinary temperature to 300°C, not discolored, having quick-drying properties, having a paint film strength not peeled even by friction between the steel materials, in which the paint film is not dissolved and printed marks are hard to be disappeared, further, sharply performing printing even marking using the narrow nozzle of a printer, and the nozzle is hard to be clogged as well, and, upon its clogging, it can be simply solved with an alkaline aqueous solution, and also provided is an aqueous paint and a dry coating film solubilizer jointly containing no volatilizable organic solvents having a reduced load applying to the human body and environment.SOLUTION: Provided is a water-based paint for a ferrous material comprising: an alkali soluble acrylic resin with a molecular weight of 8,000 to 12,000 in 6 to 15 wt.%; an all acrylic type acrylic resin-containing emulsion in 5 to 12 wt.%; an alkaline aqueous solution in 50 wt.% or more; and a pigment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a water-based paint which can be suitably used for marking steel materials and a dry paint film dissolving agent for the water-based paint. Specifically, the water-based paint strongly adheres to a steel material with a wide temperature range from room temperature to 300 ° C. and does not discolor, has a quick drying property, and has a coating strength that is difficult to peel off even by friction between steel materials, The printed marks are hard to disappear because the paint film does not melt due to rainwater, etc.In addition, even if the marking uses the thin nozzle of the printing device, it can be printed clearly and the nozzle is hard to clog. It is a water-based paint that can be easily eliminated with an alkaline aqueous solution. In addition, since both the water-based paint and the dry paint film dissolving agent for the water-based paint do not contain a volatile organic solvent, they are a water paint and a dry paint film dissolving agent for the water-based paint that have a low load on the human body and the environment.

  In steel material manufacturing factories and the like, characters and symbols indicating materials and applications, lines for indicating processing positions, etc. are marked on the surface of steel materials such as steel plates and steel parts for a long time.

  Marking at a work site is not only performed on a steel material at room temperature, but is often performed on a steel material having a temperature of about 100 to 300 ° C.

  Therefore, marking paints used on steel materials can be clearly printed on steel materials at temperatures of about 300 ° C as well as at room temperature, and they do not discolor and adhere strongly to the friction between steel materials. However, it is difficult to peel off, and the property that the coating film is not dissolved by rain water or the like and the mark is difficult to disappear is required.

  In many cases, coatings for steel materials are manufactured by dissolving a resin such as cellulose resin or acrylic resin in a highly soluble volatile organic solvent and dispersing the pigment. Since the paint used is flammable and there is a risk of fire, the amount handled and stored is strictly regulated by the Fire Service Act.

  In addition, volatile organic solvents may adversely affect the human body and the environment, so the amount handled is limited by the PRTR (Pollutant Release and Transfer Register) system, and it is easy to ignite during work. Attention must be paid to this.

  In addition, marking is often performed by spraying paint from the thin nozzles of the printing device and attaching dot-like paint (dots) to the surface of the steel material, which makes it difficult for the nozzles to clog for work efficiency. In addition, it is required to have a property of easily eliminating clogging when clogging occurs.

  However, in the case of a paint using a volatile organic solvent as described above, since the volatile organic solvent is also used for the dry film dissolving agent used to eliminate clogging, the paint is dried like the paint. Storers and users need to be careful about coating film dissolving agents.

  Therefore, it is possible to clearly print on steel materials with a wide temperature range from room temperature to 300 ° C, and the mark does not change color, and it has strong coating strength that does not peel off due to friction between steel materials, rainwater, etc. The coating mark does not melt and the printed mark is hard to disappear, and even if marking is done using the thin nozzle of the printing device, the nozzle is not clogged, but it can be easily resolved when clogged, In addition, development of a water-based paint that does not contain a volatile organic solvent and development of a dry film dissolving agent for the water-based paint are desired.

JP-A-2005-336379

  Patent Document 1 includes a plurality of volatile organic solvents with different boiling points, volatilizes the organic solvent stepwise depending on the steel plate temperature, changes the viscosity, and suppresses paint scattering, thereby allowing a wide temperature range from room temperature to 300 ° C. There is described a steel plate printing paint that maintains the same dot diameter even when marking on a steel plate of a width, does not change color, and does not easily erase marks or the like that are strongly adhered and printed.

  However, since a volatile organic solvent is used, there are problems that care must be taken during storage and use, and the handling amount is limited by the PRTR method and other rules.

  Therefore, the present inventors made it a technical problem to solve the above-mentioned problems, and as a result of many trial and error trial manufactures and experiments, the alkali-soluble acrylic resins 6 to 15 having a molecular weight of 8000 to 12000 were obtained. If it is a water-based paint that contains 5% to 12% by weight of an emulsion containing 5% by weight, all acrylic acrylic resin, 50% by weight or more of an alkaline aqueous solution, and a pigment, it strongly adheres to steel materials with a wide temperature range from room temperature to 300 ° C. The coating does not discolor, is quick-drying, has a coating strength that does not easily peel off due to friction between steel materials, and the coating marks do not melt due to rainwater, etc. Even if marking is done using a nozzle, the dod is clear without bleeding and the nozzle is difficult to clog, but when clogged, it becomes an aqueous paint that can be easily removed with an alkaline aqueous solution, In addition, since both the water-based paint and the dry paint film dissolving agent of the water-based paint do not use a volatile organic solvent, the water paint and the dry paint film dissolving agent of the water-based paint have a low load on the human body and the environment. The knowledge which should be obtained was acquired and this invention was completed.

  The technical problem can be solved by the present invention as follows.

  The present invention relates to an aqueous steel material containing 6-15% by weight of an alkali-soluble acrylic resin having a molecular weight of 8000-12000, 5-12% by weight of an all-acrylic acrylic resin-containing emulsion, 50% by weight or more of an alkaline aqueous solution, and a pigment. It is a paint (claim 1).

  The present invention also provides the water-based paint for steel materials according to claim 1, wherein the hydroxyl value of the alkali-soluble acrylic resin is 50 to 200 KOH / g (claim 2).

  Further, the present invention is the water-based paint for steel materials according to claim 1 or 2, wherein the alkali-soluble acrylic resin is a carboxyl group-containing acrylic resin (claim 3).

  The present invention is the water-based coating material for steel materials according to any one of claims 1 to 3, wherein the all-acrylic acrylic resin-containing emulsion has a solid content of 30 to 70% by weight (claim 4).

  Further, the present invention is the aqueous paint for steel materials according to any one of claims 1 to 4, wherein the glass transition temperature of both the alkali-soluble acrylic resin and the acrylic resin contained in the acrylic resin-containing emulsion is 50 to 90 ° C. Claim 5).

  Further, the present invention is the aqueous paint for steel materials according to any one of claims 1 to 5, wherein the alkaline aqueous solution is an aqueous solution containing 0.5 to 10% by weight of ammonia (claim 6).

  Further, the present invention is the water-based paint for steel materials according to any one of claims 1 to 6, wherein the pigment content is 10 to 20% by weight (claim 7).

  Further, the present invention is the water-based paint for steel materials according to any one of claims 1 to 7, further comprising at least one selected from dipropylene glycol n-butyl ether and tripropylene glycol n-butyl ether (claim 8). ).

  Further, the present invention is the dry paint film dissolving agent for an aqueous coating material for steel materials according to any one of claims 1 to 8, which is an alkaline aqueous solution (claim 9).

  The present invention also provides the dry coating film dissolving agent according to claim 9, wherein the alkaline aqueous solution is an aqueous solution containing 0.1 to 10% by weight of ammonia (claim 10).

  The water-based paint according to the present invention strongly adheres to a steel material having a wide temperature range from room temperature to 300 ° C. and does not discolor, and even if marking is performed using a printing device with a thin nozzle, the dots do not blur and adhere clearly. It is a water-based paint.

  In addition, the water-based paint is quick-drying, has a coating strength that is difficult to be peeled off even by friction between steel materials, and does not dissolve in water, so that it can be applied even when exposed to rainwater or the like. Since the film does not dissolve, it is a water-based paint in which printed marks and the like are very difficult to disappear.

  In addition, since the dried coating film does not dissolve in water but dissolves in an alkaline aqueous solution, even if the paint remaining on the thin nozzles of the printing apparatus dries and solidifies, it becomes easily clogged with the alkaline aqueous solution. Since clogging can be eliminated, work efficiency is excellent.

  Moreover, since the viscosity of the water-based paint does not become too high, it can be used for a printing device with a thin nozzle.

  In addition, since both the water-based paint and the dry paint dissolving agent of the water-based paint do not contain a volatile organic solvent, they can be stored without being restricted by the Fire Service Act, and there is no risk of ignition during use. The human body and environment are less affected.

It is the photograph which compared the state of the coating film at the time of marking on the 300 degreeC steel material.

  The content of the alkali-soluble acrylic resin in the water-based paint according to the present invention is preferably 6 to 15% by weight, and more preferably 10 to 15% by weight.

  If the amount of the alkali-soluble acrylic resin is less than 6% by weight, the viscosity of the water-based paint becomes too low, and the dod when marking with a printing device becomes unclear. This is because the color changes when printed on a steel material at ℃.

  The alkali-soluble acrylic resin preferably has a molecular weight of 8000 to 12000. If the molecular weight is less than 8000, it is difficult to form a coating film, and if it is higher than 12000, the viscosity rises too much when dissolved in an alkaline aqueous solution, and there is a risk of clogging in the middle of marking with a thin nozzle printing device. is there.

  The hydroxyl value of the alkali-soluble acrylic resin is preferably 50 to 200 mgKOH / g. This is because if the hydroxyl value is less than 50 mg KOH / g, the viscosity is excessively increased, and if it is higher than 200 mg KOH / g, sufficient coating strength cannot be obtained.

  The alkali-soluble acrylic resin preferably contains a carboxyl group. This is because heat resistance and weather resistance are improved.

  Examples of the alkali-soluble acrylic resin that can be used in the present invention include ARUFON (registered trademark) UC-3000 (manufactured by Toagosei Co., Ltd.).

  The content of the all-acrylic acrylic resin emulsion in the water-based paint according to the present invention is preferably 5 to 12% by weight, and more preferably 5 to 10% by weight.

  If it is less than 5% by weight, it changes color when marking on a steel material at 300 ° C., and if it is more than 12% by weight, the film forming property at room temperature is poor and sufficient coating strength cannot be obtained.

  The all-acrylic acrylic resin-containing emulsion in the present invention is not particularly limited, but the solid content is preferably 30 to 70% by weight. If the solid content is lower than 30% by weight, it is difficult to form a coating film. If the solid content is higher than 70% by weight, the viscosity of the paint will increase too much, and if it is a thin nozzle, clogging may occur during marking. is there.

  Examples of the all-acrylic acrylic resin emulsion that can be used in the present invention include Movinyl (registered trademark) 6800 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

  The glass transition temperature (Tg) of the acrylic resin contained in the alkali-soluble acrylic resin and the all-acrylic acrylic resin emulsion in the present invention is preferably 50 to 90 ° C.

  This is because when the glass transition temperature is lower than 50 ° C., the steel material having a temperature of 300 ° C. is discolored when it is marked, and when the glass transition temperature is higher than 90 ° C., the film forming property at room temperature is deteriorated.

  The content of the alkaline aqueous solution in the water-based paint according to the present invention is 50% by weight or more.

  If the amount is less than 50% by weight, the alkali-soluble acrylic resin may not be completely dissolved, and the viscosity of the water-based paint may increase so much that the fine nozzle may be clogged.

  The alkaline aqueous solution is not particularly limited as long as it dissolves the alkali-soluble acrylic resin, but a 0.5 to 10% by weight ammonia aqueous solution is preferable.

  This is because if the amount of the ammonia water is less than 0.5% by weight, the alkali-soluble acrylic resin may not be completely dissolved, and if it is higher than 10% by weight, it is designated as a deleterious substance and requires care.

  The pigment content in the aqueous paint according to the present invention is preferably 10 to 20% by weight.

  If the amount is less than 10% by weight, the color of the steel material may not be completely shielded. If the amount is more than 20% by weight, the viscosity is excessively increased.

  Although the pigment in this invention is not specifically limited, White pigments, such as titanium dioxide, a calcium carbonate, barium sulfate, black pigments, such as carbon black, an organic coloring pigment, and metal powder can be used conveniently.

  In the present invention, an all-acrylic acrylic resin emulsion film-forming aid can be added.

  Examples of film forming aids include dipropylene glycol n-butyl ether and tripropylene glycol n-butyl ether.

  The film-forming aid is preferably 5 to 15% by weight, more preferably 9 to 10% by weight, based on the solid content of all acrylic acrylic resin emulsion.

  If the amount is less than 5% by weight, the film-forming property of the all-acrylic acrylic resin emulsion may be weakened.

  The dry coating film dissolving agent in the present invention is not particularly limited as long as it is an alkaline aqueous solution in which the aqueous paint according to the present invention is dissolved, but an aqueous ammonia solution is preferable.

  The content of ammonia in the dry coating film dissolving agent is preferably 0.1 to 10% by weight, and more preferably 0.1 to 5% by weight.

  If the amount is less than 0.1% by weight, the dried coating may not dissolve sufficiently and clogging of the nozzle may not be resolved. If it exceeds 10% by weight, the dried coating will dissolve, but it is designated as a deleterious substance. This is because handling is necessary.

  The water-based paint in the present invention can contain an appropriate amount of alcohol as a stabilizer, rust inhibitor, antifoaming agent, antifreeze agent, and drying accelerator, if necessary.

  The water-based paint according to the present invention contains an alkali-soluble acrylic resin, an all-acrylic acrylic resin emulsion and a pigment in an alkaline aqueous solution and stirred to dissolve the resin, and the acrylic resin and pigment contained in the emulsion are homogeneous. It can be produced by dispersing in a glass.

  Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited thereto.

  The water paint of each Example and the comparative example was manufactured by mixing and stirring by the quantity as shown to Tables 1-2.

  ARUFON UC-3000 is used as the alkali-soluble acrylic resin, 6800 is used as the all-acrylic acrylic resin emulsion, and Dawanol (registered trademark) DPnB glycol ether and Dawanol TPnB glycol ether (made by Dow Chemical Japan Co., Ltd.) are used as the film-forming aid. did.

(Heat-resistant)
Each water-based paint was marked with a mark printed on each steel material heated to room temperature, 100 ° C., 200 ° C. and 300 ° C. with a test medium temperature printing device (manufactured by Marktec Co., Ltd.) and visually observed.

  A mark printed on a steel plate at 300 ° C. was evaluated as “◯” when the mark did not change, and “X” when the mark was changed.

(water resistant)
After the marks printed on each steel plate at room temperature, 100 ° C., 200 ° C. and 300 ° C. were dried, water was sprayed and wiped off, and the state of the marks was observed visually.

  Evaluations were made with ○ indicating that the mark was maintained without being dissolved, and × indicating that the mark was dissolved and wiped off.

(Binding property)
Use a cutter to put 10 grid-like cuts at 1 mm intervals into a mark on a steel plate at room temperature, attach cellophane tape, rub it from the top with an eraser and bond it well, peel off the cellophane tape, and visually check the mark. Observed.

  The case where the mark was not peeled off by the cellophane tape was evaluated as ◯, and the case where the film was not formed but was peeled off was evaluated as ×.

  A glass plate was immersed in the water-based paint of Example 3 and dried at room temperature for 30 minutes. The glass plate was immersed for 30 seconds in various aqueous solutions of triethanolamine, sodium hydroxide and ammonia having the concentrations shown in Table 4, and the state of the coating film was visually observed.

  The evaluation method is shown in Table 3, and the concentrations of various aqueous solutions and the evaluation points are shown in Table 4.

After performing the printing operation of each water-based paint of Examples 1 to 3 with a medium-temperature printing device for testing, the water-based paint from the nozzle can be left even if the water-based paint at the tip of the nozzle is dried and the printing operation is performed. Was not clogged, so-called clogging.
Next, after replacing the dry paint in the printing apparatus piping with each of the dry paint film dissolving agents listed in Table 5, a printing operation was performed to check the discharge state of the nozzles.

  ○ When water-based paint is ejected from the nozzle and printable, ○ Water-based paint is ejected from the nozzle, but characters are confused and print quality is poor. As evaluated.

  Aqueous paints of Comparative Examples 10 to 18 were prepared by stirring 15% by weight of various alkali-soluble acrylic resin solids described in Table 6, 10% by weight of titanium white, and 3% by weight of ammonia water and mixing them uniformly.

  The water-based paints of Comparative Examples 10 to 18 were evaluated for water resistance, binding property and heat resistance in the same manner as in the examples.

  Further, after immersing a glass plate in each of the water-based paints of Comparative Examples 10 to 18 and allowing them to stand at room temperature for 30 minutes to form a dry coating film, 5 wt% ammonia water, 5 wt% NaOH aqueous solution and 5 wt% The film was immersed in a triethanolamine aqueous solution for 30 seconds, and the state of the coating film was visually observed.

  The case where the glass plate was transparent and the coating film was dissolved was evaluated as ◯, and the case where the glass plate was white and cloudy and was not completely dissolved was evaluated as Δ.

  From Tables 1 to 6, if it is a water-based paint according to the present invention, a mark can be clearly printed on a steel plate at room temperature, 100 ° C., 200 ° C. and 300 ° C., and the mark has water resistance and friction. It was proved that it was difficult to be peeled off by such as and no discoloration was observed.

  Further, it was proved that the dry paint film of the water-based paint dissolves in an alkaline aqueous solution, particularly ammonia water, and can be easily eliminated even if the nozzle is clogged.

The water-based paint according to the present invention strongly adheres to a steel material having a wide temperature range from room temperature to 300 ° C. and does not discolor, has a quick drying property, is not easily peeled off by friction between steel materials, and is dried by rainwater or the like. Since the coating film does not dissolve, the printed marks are difficult to disappear, and even if marking is performed using a thin nozzle of the printing device, the dot can be clearly printed and the nozzle is not clogged easily, A water-based paint that can be easily removed with an alkaline aqueous solution when clogged, and the water-based paint and the dry paint dissolving agent of the water-based paint do not use a volatile organic solvent. Is a water-based paint with a small amount of water and a dry paint film dissolving agent for the water-based paint.
Therefore, the present invention is highly industrially applicable.

Claims (10)

An aqueous paint for steel materials containing 6 to 15% by weight of an alkali-soluble acrylic resin having a molecular weight of 8000 to 12000, 5 to 12% by weight of an all-acrylic acrylic resin-containing emulsion, 50% by weight or more of an alkaline aqueous solution, and a pigment. 2. The aqueous paint for steel materials according to claim 1, wherein the hydroxyl value of the alkali-soluble acrylic resin is 50 to 200 KOH / g. 3. The aqueous paint for steel materials according to claim 1, wherein the alkali-soluble acrylic resin is a carboxyl group-containing acrylic resin. 4. The water-based paint for steel materials according to claim 1, wherein the solid content of the all-acrylic acrylic resin-containing emulsion is 30 to 70% by weight. 5. The aqueous paint for steel materials according to claim 1, wherein the glass transition temperature of the alkali-soluble acrylic resin and the acrylic resin contained in the acrylic resin-containing emulsion is 50 to 90 ° C. 6. The aqueous paint for steel materials according to claim 1, wherein the alkaline aqueous solution is an aqueous solution containing 0.5 to 10% by weight of ammonia. The water-based paint for steel materials according to any one of claims 1 to 6, wherein the pigment content is 10 to 20% by weight. The water-based paint for steel materials according to any one of claims 1 to 7, further comprising at least one selected from dipropylene glycol n-butyl ether and tripropylene glycol n-butyl ether. 9. The dry paint film dissolving agent for a water-based paint for steel materials according to any one of claims 1 to 8, which is an alkaline aqueous solution. 10. The dry coating film dissolving agent according to claim 9, wherein the alkaline aqueous solution is an aqueous solution containing 0.1 to 10% by weight of ammonia.