KR100725249B1 - Ultraviolet curable paint for steels coating - Google Patents

Abstract

Provided is a UV curable coating agent for coating iron materials, which forms a coating film showing excellent adhesion to iron materials and anti-corrosive property and having excellent scratch resistance, saline resistance and water resistance. The UV curable coating agent for coating iron materials comprises: 25-40 wt% of an acrylate oligomer containing an epoxy acrylate oligomer and an urethane acrylate oligomer; 15-25 wt% of a reactive acryl monomer; 20-30 wt% of a pigment; 5-10 wt% of a photoinitiator; 0.5-5 wt% of an adhesion enhancer; and 3-5 wt% of additives including a dispersant, defoaming agent and colorant. The acrylate oligomer comprises 20-30 wt% of the epoxy acrylate oligomer and 5-10 wt% of the urethane acrylate oligomer. The reactive acryl monomer includes at least one monomer selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, tetrahydrofuryl acrylate, 2-phenoxyethyl acrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate and acryloyl morpholine. The adhesion enhancer is represented by a formula 2, wherein n is 0 or 1, and each of a and b is a rational number of 1-2.

Description

Ultraviolet Curable Paint For Steels Coating

The present invention relates to an ultraviolet curable paint, and more particularly, to an ultraviolet curable paint for iron coating excellent in adhesion to steel substrates.

In general, UV curable paints include oligomers, monomers, photoinitiators and additives, and when pigmented coating is required, colored pigments may be used. In general, the photoinitiator among the components of the ultraviolet curable paint serves to generate radicals by ultraviolet rays, and the radicals generated by the photoinitiator attack the double bonds of the oligomer and the monomer to cross-link to a three-dimensional network to be cured. A coating film is formed.

The coating film formed of the ultraviolet curable paint should be required to have high adhesion to the steel material. This is because adhesion, chemical resistance, etc. are reduced when the adhesion of the coating film is small.

However, currently used UV curable paints have a disadvantage that color coatings, in particular, black coatings are not possible, as well as low adhesion and rust resistance to steel materials such as wire steel or cold rolled steel.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultraviolet curable coating material for iron coating, which is excellent in adhesion and rust prevention property to steel substrates, and forms a colored or black coating film.

The present invention for achieving the above object is UV coating material for iron coating is 25 to 40% by weight of acrylate oligomer containing epoxy acrylate oligomer and urethane acrylate oligomer, 15 to 25% by weight of reactive acrylic monomer, pigment 20 to 30% by weight, 5 to 10% by weight photoinitiator, 0.5 to 5% by weight adhesion promoter, and 3 to 5% by weight of an additive including a dispersant, an antifoaming agent, and a colorant.

The acrylate oligomer comprises 20 to 30 wt% of the epoxy acrylate oligomer and 5 to 10 wt% of the urethane acrylate oligomer in total weight%.

Examples of the epoxy acrylate oligomer include bisphenol A-type epoxy acrylate, modified epoxy acrylate, and mixtures thereof. Examples of the urethane acrylate oligomer include a yellowing-free urethane acrylate oligomer or an aliphatic urethane oligomer having 6 or more functional groups. Etc. can be mentioned.

UV-curing coating material for steel coating having the above-described composition is not only excellent in adhesion to steel materials such as wire steel or cold rolled steel sheet, but also excellent in scratch resistance, salt water resistance, water resistance, and the like. It can be usefully used.

Hereinafter, the ultraviolet curing paint for iron coating of the present invention will be described in detail.

The ultraviolet curable paint for iron coating of the present invention is an ultraviolet curable paint for coating on steel substrates, and includes an acrylate oligomer, a reactive acrylic monomer, a pigment, a photoinitiator, an adhesion promoter, an additive, and the like.

In particular, the UV-curable coating material for iron coating is 25 to 40% by weight of an acrylate oligomer comprising an epoxy acrylate oligomer and a urethane acrylate oligomer, 15 to 25% by weight of a reactive acrylic monomer, 20 to 30% by weight of a pigment, And 5 to 10 weight percent of photoinitiator, 0.5 to 5 weight percent of adhesion promoter, and 3 to 5 weight percent of additive including dispersing agent, antifoaming agent, and coloring agent.

Specifically, the acrylate oligomer applied to form the UV-curable coating material for iron coating includes an epoxy acrylate oligomer and a urethane acrylate oligomer. At this time, the sum of the content of the epoxy acrylate oligomer and the urethane acrylate oligomer preferably has a range of 25 to 40% by weight based on the total weight of the coating composition.

If the content of the acrylate oligomer including the epoxy acrylate oligomer and the urethane acrylate oligomer is less than 25% by weight, the rust resistance and water resistance deteriorate, and when the content exceeds 40% by weight, the viscosity of the paint formed and the paint This is because the price of the problem is caused to increase.

Bisphenol A type epoxy acrylate, modified epoxy acrylate, etc. are mentioned as an example of the said epoxy acrylate oligomer. These may be used alone or in combination. In addition, examples of the commercially available epoxy acrylate oligomers may include the brand names CN 120, CN 124, CN 104, CN 117, CN 119, CN 136, CN 150/80, etc. of SARTOMER.

If the content of the epoxy acrylate oligomer contained in the paint is less than 20% by weight, the disadvantage of deterioration in corrosion resistance and chemical resistance to the steel material is caused, the price of the paint to be formed when the content exceeds 30% by weight This becomes expensive, and the viscosity of the paint is increased, resulting in a problem in workability.

Therefore, the epoxy acrylate oligomer is included in 20 to 30% by weight, preferably 22 to 28% by weight in 100% by weight of the paint.

In addition, the urethane acrylate oligomer is a urethane acrylate oligomer having at least six functional groups in consideration of the light curing rate, water resistance and the like. These may be used alone or in combination. Specifically, examples of commercially available urethane acrylate oligomers include aliphatic urethanes such as Oligomer U-6LHA (6 functional group), U-520 (10 functional group), and U-15HA (15 functional group) of NK Corporation. Oligomers.

When the content of the urethane acrylate monomer included in the paint is less than 5% by weight, the water resistance of the coating film formed by the paint is deteriorated, thereby causing a blister phenomenon on the surface of the coating film, and the scratch resistance of the coating film is deteriorated. do. On the other hand, if the content exceeds 10% by weight, the viscosity of the paint formed and the price of the paint are high. Therefore, the urethane acrylate monomer is contained in 5 to 10% by weight, preferably 6 to 9% by weight in 100% by weight of the paint.

Examples of the reactive acrylic monomer included in the ultraviolet ray-curing paint for steel are isobonyl acrylate (isobonyl acrylate: IBOA), isobonyl methacrylate (IBOMA), tetrahydrofuryl acrylate (THFA), 2 -Phenoxyethyl acrylate (2-phenoxyethyl acrylate), tripropyleneglycol diacrylate (TPGDA), 1, 6-hexanediol diacrylate (1, 6-hexane diol diacrylate (HDDA)), trimethylolpropane Trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), acryloyl morpholine (ACMO), and the like. These may be used alone or in combination.

Here, the reactive acrylic monomers are preferably used individually or in combination, respectively, in consideration of the adhesion, curing time, price, etc. of the coating film formed of the ultraviolet curing paint for steel to be formed.

In particular, in the present invention, it is preferable to use acryloyl morpholine represented by the following structural formula (1) as the reactive acrylic monomer, and isobonyl acrylate and acryloyl morpholine can be mixed and used. The acryloyl morpholine is a monomer that improves the low odor, adhesion, chemical resistance and the like of isobornyl acrylate (IBOA) widely applied as a reactive diluent with good adhesion.

------구조식 (1)

------ Structure (1)

When the content of the reactive acrylic monomer is less than 15% by weight, the viscosity of the formed paint is too high, causing workability problems, and when the content exceeds 25% by weight, the paint formed is reduced in adhesion to the steel material The problem is caused. Therefore, the reactive acrylic monomer is included in 15 to 25% by weight, preferably 18 to 23% by weight in 100% by weight of the paint.

As the photoinitiator, a conventional polymerization initiator which is activated by ultraviolet rays is used. Examples of the polymerization initiator include benzophenone series, benzoin, benzoin ether series, benzyl ketal series, acetophenone series, anthraquinone series, and thi Compounds, such as an oxo xanthone type, are mentioned. These may be used alone or in combination of two or more. Examples of the commercially available and commercially available polymerization initiators include Irgacure 184, 651, 819 by CIBA GEIGY, Micure MP-8 by Miwon, Benzophenone and the like.

When the content of the photoinitiator contained in the UV-curing paint for iron coating is less than 5% by weight, the curing time of the paint coated on the steel material is increased, the workability is lowered, and if the content exceeds 10% by weight to form This leads to a problem that the price of the paint is increased and the storage stability of the paint is lowered. Therefore, the photoinitiator is contained in 5 to 10% by weight, preferably 6 to 9% by weight in 100% by weight of the paint.

The pigment may be used for all pigments applied to conventional UV curable paint. That is, in general, a pigment is a substance that gives the color of the paint in the paint and its type may vary depending on the object. Specifically, examples of the pigment to be used to form the paint include rust preventive pigments, extender pigments or mixtures thereof. Zinc-based pigments were used as anti-rust pigments, and talc-based pigments were used as extender pigments.

When the content of the pigment contained in the UV-curing coating material for steel coating is less than 20% by weight, the coating film formed on the steel material has a problem that the adhesion strength is lowered and the rust resistance and chemical resistance is inferior. On the other hand, when the content exceeds 30% by weight, the resulting paint viscosity is increased, which results in a problem of deterioration of workability. Therefore, the pigment is included 20 to 30% by weight, preferably 22 to 28% by weight in 100% by weight of the paint.

The adhesion promoter is a material that is included in the UV-curable coating material for iron coating to enhance the adhesion of the coating film formed on the steel material. In particular, it is preferable to use an adhesion promoter represented by the following structural formula (2) because the ultraviolet curable coating material for iron coating of the present invention is important to adhere to steel substrates.

---구조식 (2)

--- Structure (2)

In the structural formula, n is 0 or 1, a is 1 to 2 rational number, b is 1 to 2 rational number. More preferably n is 0, a is 1.5 and b is 1.5.

If the content of the adhesion promoter included in the UV-curing paint for steel coating is 0.5% by weight, the adhesion of the coating film to the steel material is significantly lowered, if the content exceeds 5% by weight the adhesion of the coating film is constant Converge within range. Therefore, the adhesion promoter is contained in 0.5 to 5% by weight, preferably 0.5 to 3% by weight in 100% by weight of the paint.

In addition, the ultraviolet curing paint for iron coating may use all the additives used in the existing ultraviolet curing paint. That is, in general, the use of additives is not limited because the additives are added in a very small amount in order to optimize the elements that have a slight influence on the manufacturability and the workability in the paint. As an example of the said additive, an antifoamer, a dispersing agent, a leveling agent, a coloring agent, etc. are mentioned. Since the amount of use differs depending on the type of the additive, the amount of use and the type of the additive of the present embodiment are not limiting elements of the present invention. Preferably, the ultraviolet curable coating material for iron coating contains 3 to 5 wt% of an additive including a dispersant, an antifoaming agent, and a coloring agent. In particular, in the present invention, the colorant includes 1 to 2.5% by weight.

Hereinafter, the present invention will be described in detail through specific examples and evaluation examples of the present invention. However, the present invention is not limited to the following examples and evaluation examples.

Example 1

30% by weight epoxy acrylate oligomer, 5% by weight urethane acrylate oligomer (U-15HA from NK Oligomer), 10% by weight 1,6-hexanediol diacrylate (HDDA), 15% by weight isobornyl acrylate (IBOA) %, 5% by weight of acryloyl morpholine (ACMO), 5% by weight of photoinitiator (Irgacure 184 by CIBA GEIGY), 0.2% by weight of dispersant, 0.3% by weight of antifoam, 25% of rust and extender pigment, carbon black as a coloring agent A weight-%, 2.5% by weight of adhesion promoter was mixed and then dispersed in a disperser to prepare a UV-curing paint for iron coating. The composition of the material applied to prepare the paint is shown in Table 1 below.

Example 2

Prepared in the same manner as in Example 1, but to prepare a UV-curing paint for iron coating having a composition corresponding to the second combination of Table 1.

Example 3

Prepared in the same manner as in Example 1, but to prepare a UV-curing paint for iron coating having a composition corresponding to the third blend of Table 1.

Comparative Example 1

Prepared in the same manner as in Example 1, but to prepare a UV-curing paint for iron coating having a composition corresponding to the fourth blend of Table 1.

Comparative Example 2

Prepared in the same manner as in Example 1, but to prepare a UV-curing paint for iron coating having a composition corresponding to the fifth blend of Table 1.

Comparative Example 6

Prepared in the same manner as in Example 1, but to prepare a UV-curing paint for iron coating having a composition corresponding to the sixth combination of Table 1.

TABLE 1

Raw material First formulation Second formulation Third formulation Fourth combination Fifth formulation 6th combination Epoxy acrylate 30 30 25 35 40 30 Urethane acrylate U-6LHA × × × × 5 × U-15HA 5 5 10 5 × 5 Reactive monomer HDDA 10 9 10 10 10 10 IBOA 15 10 15 15 15 15 ACMO 5 10 5 × 5 7.5 Photoinitiator 5 5 5 5 5 5 additive Dispersant 0.2 0.2 0.2 0.2 0.2 0.2 Antifoam 0.3 0.3 0.3 0.3 0.3 0.3  coloring agent 2 2 2 2 2 2 Adhesion promoter 2.5 1.5 2.5 2.5 2.5 × Pigment Sieving pigment 20 20 20 20 10 20 Antirust pigment 5 5 5 5 5 5 Sum 100 100 100 100 100 100

(Unit: weight%)

Coating Film Evaluation of UV Curing Paint for Steel Coating

Each of the ultraviolet curable coating material for iron coating manufactured by Examples 1 to 3 and Comparative Examples 1 to 3 was applied to an iron plate (CR steel sheet) with an applicator to a thickness of 20 to 30 μm, and then to an ultraviolet curing device ( 1500-2000 mJ / cm ² , 3-5 m / min) to obtain a cured coating specimen. In addition, the physical properties of the cured coating film specimens were measured according to the following physical property measurement methods. The results are shown in Table 2 below.

TABLE 2

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 UV curable O ◎ O O O O Adhesion ◎ ◎ ◎ △ △ × Scratch resistance O ◎ O O △ O Saline resistance O O O △ △ × Water resistance O O O △ △ × ◎: Excellent, O: Good, △: Normal, ×: Poor

(1) Ultraviolet curability: Curability measurement After passing through a UV curing apparatus using an illuminometer (IL 393A), it was observed whether the cured coating film was Tack-Free.

(2) Adhesiveness: It measured according to JISD0202.

(3) Scratch resistance: The coating was pressed with the same force with a coin to scratch, and the scratch was visually observed.

(4) Saline resistance: After immersion in 5% aqueous sodium chloride solution for 240 hours, the coating state was observed.

 (5) Water resistance: After immersion in 50% aqueous ethanol solution at room temperature for 24 hours, the coating state was observed.

Referring to Table 2, as can be seen from the physical property evaluation results for Examples 1 to 3, the obtained UV-curable coating material for iron coatings has various physical properties such as UV curability, adhesion, scratch resistance, salt water resistance, and water resistance. Etc. are superior to the paints obtained in Comparative Examples.

As described above, the ultraviolet curable coating material for iron coating according to the present invention not only has excellent adhesion to steel materials such as wire steel or cold rolled steel sheet, but also has excellent scratch resistance, salt water resistance, water resistance, and the like. Have Therefore, it can be usefully used for automobile parts in which steel parts are used.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (7)

25 to 40 wt% of an acrylate oligomer comprising an epoxy acrylate oligomer and a urethane acrylate oligomer; 15 to 25% by weight reactive acrylic monomer; Pigment 20 to 30% by weight; 5 to 10 weight percent photoinitiator; 0.5-5% by weight of adhesion promoter; And 3 to 5% by weight of an additive comprising a dispersant, an antifoam, and a colorant, The acrylate oligomer comprises 20 to 30% by weight of the epoxy acrylate oligomer and 5 to 10% by weight of the urethane acrylate oligomer in the total weight%, the reactive acrylic monomer is isobonyl acrylate (isobonyl acrylate), isobonyl Methacrylate, tetrahydrofuryl acrylate, 2-phenoxyethyl acrylate, tripropyleneglycol diacrylate, 1, 6-hexanediol diol At least one selected from the group consisting of acrylate (1, 6-hexane diol diacrylate), trimethylolpropane triacrylate, pentaerythritol triacrylate, and acryloyl morpholine A monomer of, wherein the adhesion promoter is Ultraviolet curable coating composition for coating steel, characterized in that denoted by (2).

--- Structure (2) (In Structural Formula (2), n is 0 or 1, and a and b are rational numbers of 1 to 2, respectively.) delete The method of claim 1, wherein the epoxy acrylate oligomer is bisphenol A-type epoxy acrylate, modified epoxy acrylate or a mixture thereof, ultraviolet curing paint for iron coating. The method of claim 1, wherein the urethane acrylate oligomer is a non-yellowing urethane acrylate oligomer or aliphatic urethane oligomer having a six functional group or more, UV-curing paint for iron coating. delete The ultraviolet curable coating material for iron coating according to claim 1, wherein the reactive acrylic monomer is a monomer represented by the following Structural Formula 1.

------ Structure (1) delete