CN102286235A - Aqueous one-pack type coating material and method for forming high gloss coating layer using the same - Google Patents

Abstract

The present invention provides an aqueous one-pack type paint and a method of forming a high-gloss coating layer using the same. The aqueous one-pack type coating material comprises: 40 to 80 parts by weight of a water-based acrylic resin; 5-15 parts by weight of a pigment; 0.1-3 parts by weight of a coating additive; and 3-15 parts by weight of a film-forming aid.

Description

Water-based one-component paint and method for forming high-gloss coating using same

technical field

The present invention relates to a paint, and more particularly to a one-liquid type paint and a method for forming a high-gloss coating.

Background technique

The 3C products currently on the market, in order to improve the texture of the product appearance (usually a plastic shell), usually require the gloss of the product to reach a reflectivity of more than 85% at a 60-degree angle of the gloss meter, so as to meet the market demand.

Currently known methods for improving the glossiness of articles include the following methods: mold polishing, spraying UV coatings or two-component coatings. Among them, mold polishing or spraying UV coatings must be equipped with additional machines, thus increasing the process cost; and two-component coatings need to add hardeners (such as alcohols or amines) to help the coating harden. Generally speaking, the two-component coatings The curing time (cure time) usually needs more than three days, thus increasing the time cost and being unfavorable for production.

To sum up, the industry urgently needs to develop a high-gloss coating, which can not only save the process cost, but also shorten the curing time.

Contents of the invention

The invention provides a water-based single-component coating, comprising: 40-80 parts by weight of water-based acrylic resin (also known as water-based acrylic resin, aqueous acrylic resin); 5-15 parts by weight of pigment ; 0.1-3 parts by weight of coating additives; and 3-15 parts by weight of film-forming assistants.

The present invention also provides a method for forming a high-gloss coating, comprising the following steps: spraying the one-liquid paint of the present invention on an object; and baking the one-liquid paint to form a high-gloss coating.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments are listed below and described in detail in conjunction with the accompanying drawings.

Detailed ways

The invention provides a water-based one-component paint, which mainly includes 40-80 parts by weight of water-based acrylic resin. The water-based acrylic resin of the present invention is a synthetic resin based on (meth)acrylic compounds (compounds with (meth)acrylic groups), and is a water-dispersed or modified acrylic emulsified resin (modified -emulsified resin), the structure of which includes acrylic resin-styrene, acrylic resin-silica (silica), or acrylic resin-siloxane structure, and its weight average molecular weight (Mw) is greater than about 100,000 , preferably about 100,000 to 250,000. The so-called "modified acrylic emulsifying resin" here means that the structure in the acrylic resin can be bonded with epoxy resin or polyurethane resin. The preparation method of the water-based acrylic resin of the present invention is as follows: take a reaction bottle, add part of the acrylic monomer and initiator into it, mix uniformly first, and keep stirring, put a heater at the bottom, heat up from normal temperature to 80°C, And maintain the temperature, drop the remaining acrylic monomer, emulsifier and pre-grafted resin (polyurethane or epoxy resin) into the reaction bottle, and finish dropping in 4-8 hours, then raise the temperature to 110°C, The reaction temperature was maintained for 4 to 6 hours, and the temperature was lowered to obtain the desired acrylic resin. Examples of water-based acrylic resins that can be used are, for example, HPW511 from Tsinghua Company, SAT-177 from Lida Chemical Industry, and WL-100 from Rohm and Haas, but are not limited thereto.

In addition, the water-based one-component paint includes the following components: 5-15 parts by weight of pigments; 0.1-3 parts by weight of coating additives; and 3-15 parts by weight of film-forming assistants. The above-mentioned pigments include pigments such as red, white, black, blue or yellow, which are used to make the paint form various desired colors, so as to increase the visual effect of the water-based one-component paint. Examples of pigments that can be used are, for example, 1A408 of Dagong Company, OPBK 187W of Modern Nano Technology, and OPBK 190W of Modern Nano Technology, but are not limited thereto.

The above-mentioned coating additives include slip and leveling agent, defoamer or dispersant, wherein the leveling agent can make the water-based single-liquid coating have good smoothness when forming a film, and the defoamer is used to eliminate the coating The formed air bubbles, and the dispersant can help the components to be mixed evenly in the water-based one-component coating and reduce the interfacial tension between the components. The leveling agent that can be used is, for example, commercially available BYK 346; the defoamer that can be used is, for example, commercially available TEGO foamex 805; the dispersant that can be used is, for example, commercially available BYK 192.

The above-mentioned film-forming aid is a kind of cosolvent (cosolvent), which includes ether alcohols (ether alcohols), acid esters (acid esters), or a combination of the above substances, and its function is to help the water-based acrylic resin and other components. Mix evenly to aid in film formation. Usable coalescents are, for example, commercially available TEXANOL (Eastman Kodak), ANOL pph (Dow Chemical), DBE-IB (DuPont), DPnB (Dow Chemical) and the like.

In addition, in addition to the above components, diluents, such as water, can also be added to adjust the viscosity of the water-based one-component coating, so that the viscosity of the water-based one-component coating can be measured by the Iwata No. 2 viscosity cup (Iwata viscosity cup #2). It is about 8 to 10 seconds, preferably 8.5 to 9.5 seconds. Since the water-based acrylic resin itself has different water content, thereby affecting the viscosity of the water-based one-component coating, the viscosity of the overall water-based one-component coating can be adjusted by adding additional diluents (eg, water).

In order to improve the stability of the water-based one-component coating of the present invention, a compound with an amine group (aminegroup) can be added to the coating, so that the pH value of the water-based one-component coating is slightly alkaline, and the pH value is about 8.0 to 9.5. It can be stored at room temperature for a long time, wherein the compound having an amine group is, for example, ammonia water, primary amine, secondary amine or tertiary amine.

In one embodiment, commercially available AMP-90 or AMP-95 (Dow Chemical), dimethylethanolamine, diethylethanolamine and other compounds with amine groups can be used to adjust the pH value of the water-based one-component coating.

The mixing sequence of the components in the water-based one-component coating of the present invention is not particularly limited, as long as the components can be mixed uniformly, therefore, mechanical stirring can be used to help the mixing of the components. Since the water-based acrylic resin accounts for a relatively high content of the water-based single-component paint, in order to make the components in the paint mix evenly, in a preferred embodiment, the pigment, paint additives and film-forming aids can be mixed first, and then added Water-based acrylic resin.

The present invention also provides a method for forming a high-gloss coating, the method comprising the steps of: spraying the above-mentioned single-liquid coating (spray coat) on an object; and baking the single-liquid coating to form a high-gloss coating . The aforementioned objects (items) include plastic casings of electronic products, such as acrylonitrile-butadiene-styrene (ABS), polystyrene (PS), polycarbonate (PC), polyvinyl chloride (PVC) and other plastics.

The above-mentioned baking temperature is about 40° C. to 100° C., and the baking temperature will be adjusted according to the different objects of the paint spraying. In one embodiment, when the object is acrylonitrile-butadiene-styrene (ABS), polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS), the baking temperature is about 40°C to 60°C, preferably about 50°C to 60°C. In another embodiment, when the object is polycarbonate (PC), the baking temperature is about 65°C-100°C, preferably about 70°C-80°C.

The baking time is about 0.5 hours to 1 hour and stand for 48 hours, or forced drying and baking for 4 to 8 hours. After the above baking, the solvent in the coating can be volatilized, so that high gloss can be obtained. coating. It should be noted here that the so-called "forced drying" here is to prolong the baking time once, so that the reaction can be achieved in advance, but since the object of the substrate spraying is a molded plastic, the temperature is only the upper limit of the preferred baking temperature Mainly, there is no need to increase the temperature.

The thickness of the above-mentioned high-gloss coating is about 12-25 μm, so that the coating has a shielding effect, and it has a gloss of about 85%-100% reflectance at a viewing angle of 60 degrees, which achieves high-gloss. standard.

It should be noted here that the water-based one-component paint of the present invention is mainly composed of water-based acrylic resin, which is easier to prepare and more in line with environmental protection requirements than other oil-based paints. In addition, compared with the general two-component coating, the water-based one-component coating of the present invention does not need to add additional curing agent (curing agent), and only needs a simple heat baking method to obtain a high-gloss coating. layer, thus saving process cost and shortening process time.

Example

Example 1

Take 7 grams of pigment (1A408 from Dagong Company, which is a black color paste ground by adding water to ordinary carbon black) and dissolve it in 10 grams of co-solvent (Butyl Diglyco from BASF Company) and 10 grams of pure water, and let it stand for more than 4 hours or continuously Stir for 1 more hour.

After that, take 0.6 grams of leveling agent (BYK 349, which is a polyether modified siloxane substance), and then pour 20 grams of pure water into another cup, mechanically stir for 5 minutes, and then pour 50 gram of water-based acrylic resin (HPW511 of Tsinghua Company, acrylic resin grafted polyurethane structure resin with a solid content of 40%), mechanically stirred for 15 minutes, poured the mixture into the pigment mixture, stirred for another 30 minutes, and finally added AMP -90 to adjust the pH of the system to 8.0-9.5, then add pure water to adjust the overall viscosity until the measured viscosity of the Iwata No. 2 viscosity cup is 8.5 seconds to 9.5 seconds.

Finally, spray the paint with the above configuration on the plastic shell (PC/ABS from Mitsubishi Chemical), the dry film thickness is 12-25 μm, the baking condition is 60°C/30 minutes, and stand for 48 hours for testing. Its reflectance at a viewing angle of 60 degrees is about 90% as measured by a gloss meter sold by BYK Chemicals in Germany.

Example 2

Take 10 grams of pigment (OPBK 187W of modern nanotechnology, which is a black color paste ground by adding water to ordinary carbon black) and dissolve it in 10 grams of co-solvent (DOW's dipropylene glycol butyl ether) and 10 grams of pure water, and let it stand for more than 4 hours Or continue to stir for more than 1 hour.

Afterwards, take 0.6 gram of dispersant (BYK 346, agent of Xiequan Company, which is a polyether-modified polysiloxane substance), pour 20 grams of pure water into another cup, stir mechanically for 5 minutes, and then pour 50 gram of water-based acrylic resin (SAT-177 of Lida Chemical Industry, acrylic resin grafted with siloxane structure resin with a solid content of 50%), mechanically stirred for 15 minutes, poured the mixture into the pigment mixture, and stirred for another 30 minutes , and finally adjust the pH of the system to 8.0-9.5 with AMP-90, then add pure water to adjust the overall viscosity until the measured viscosity of Iwata No. 2 viscosity cup is 8.5 seconds to 9.5 seconds.

Finally, spray the paint with the above configuration on the plastic shell (PC/ABS from Mitsubishi Chemical), the dry film thickness is 12-25 μm, the baking condition is 60°C/30 minutes, and stand for 48 hours for testing. Its reflectance at a viewing angle of 60 degrees is about 88% as measured by a gloss meter sold by BYK Chemicals in Germany.

Example 3

Take 8 grams of pigment (OPBK 190W of modern nanotechnology, which is a black color paste ground by adding water to ordinary carbon black) and dissolve it in 8 grams of co-solvent (Butyl Glyco of BASF) and 10 grams of pure water, and let it stand for more than 4 hours or continuously Stir for 1 more hour.

After that, take 0.3 grams of leveling agent (BYK 381, which is an ionic polyacrylate substance), pour 20 grams of pure water into another cup, stir mechanically for 5 minutes, and then pour 50 grams of water-based Acrylic resin (Rohm and Haas WL-100, acrylic resin with a solid content of 41%), mechanically stirred for 15 minutes, poured the mixture into the pigment mixture, stirred for another 30 minutes, and finally mixed with AMP-90 Adjust the pH of the system to 8.0-9.5, then add pure water to adjust the overall viscosity until the measured viscosity of the Iwata No. 2 viscosity cup is 8.5 seconds to 9.5 seconds.

Finally, spray the paint with the above configuration on the plastic shell (PC/ABS from Mitsubishi Chemical), the dry film thickness is 12-25 μm, the baking condition is 60°C/30 minutes, and stand for 48 hours for testing. Its reflectance at a viewing angle of 60 degrees is about 90% as measured by a gloss meter sold by BYK Chemicals in Germany.

Although the present invention has been disclosed with several preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make any changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be subject to the scope defined by the claims.

Claims (13)

1. water-based single-liquid type coating comprises:

The water soluble acrylic acid resinoid of 40～80 weight parts;

The pigment of 5～15 weight parts;

0.1 the coatings additive(s) of～3 weight parts; And

The film coalescence aid of 3～15 weight parts.

2. water-based single-liquid type coating as claimed in claim 1 also comprises thinner.

3. water-based single-liquid type coating as claimed in claim 2, wherein this thinner comprises water.

4. water-based single-liquid type coating as claimed in claim 1, wherein the weight-average molecular weight of this water soluble acrylic acid resinoid is for approximately greater than 100,000.

5. water-based single-liquid type coating as claimed in claim 1, wherein the weight-average molecular weight of this water soluble acrylic acid resinoid is about 100,000～250,000.

6. water-based single-liquid type coating as claimed in claim 1, wherein this coatings additive(s) comprises flow agent, defoamer or dispersion agent.

7. water-based single-liquid type coating as claimed in claim 1, wherein the pH value of this water-based single-liquid type coating is about 8.0～9.5.

8. water-based single-liquid type coating as claimed in claim 1, wherein this water-based single-liquid type coating is about 8～10 seconds by the viscosity of No. 2 flow cups mensuration in rock field.

9. the formation method of high gloss coating may further comprise the steps:

With single-liquid type paint spay-coating as claimed in claim 1 on object; And

Toast this single-liquid type coating to form high gloss coating.

10. the formation method of high gloss coating as claimed in claim 9, wherein the temperature of this baking is about 40 ℃～100 ℃.

11. the formation method of high gloss coating as claimed in claim 9, wherein the time of this baking is 4～8 hours.

12. the formation method of high gloss coating as claimed in claim 9, wherein the reflectivity at 60 of this high gloss coating degree visual angles is about 〉=85%.

13. the formation method of high gloss coating as claimed in claim 9, wherein the thickness of this high gloss coating is about 12～25 μ m.