KR101050506B1 - Rheological epoxy ester coating composition and preparation method thereof - Google Patents

Abstract

The present invention relates to a bake paint primer composition having excellent chemical resistance and excellent adhesion during top coating nylon resin extrusion coating, in particular, a rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, melamine having a number average molecular weight of 500 to 2,000 The present invention relates to a rheotropic epoxy ester coating composition comprising a resin and a block isocyanate resin having a number average molecular weight of 300 to 20,000.

The rheological epoxy ester coating composition of the present invention maintains excellent adhesion and durability in UV ink coating and nylon resin extrusion coating coated with a top coat while maintaining excellent chemical resistance and rust resistance. In addition, the coating composition not only has excellent corrosion resistance but also has various mechanical and chemical properties and pick up roll (Pick Up Roll) workability, which is effective on the surface of the product as a colorant of automobile parts, industrial parts, and tape measure products of metal materials. Can be applied.

Rheological epoxy ester resin, melamine resin, block isocyanate resin, number average molecular weight, paint

Description

Rheological epoxy ester coating composition and its manufacturing method {OIL MODIFIED EPOXYESTER COATING COMPOSITION AND PROCESS FOR PREPARING THE SAME}

The present invention relates to a rheological epoxy ester coating composition having excellent durability and excellent adhesion in nylon resin extrusion coating, and a method for preparing the same. More particularly, the present invention provides excellent corrosion resistance as well as excellent chemical resistance, mechanical properties, and durability. The present invention relates to a rheological epoxy ester coating composition and a method for producing the same, having excellent adhesion in UV ink paint and nylon resin extrusion coating.

In general, corrosion of steel and non-ferrous materials is very serious in the construction and industrial sectors. Due to the corrosion of steel materials, the property and industry are seriously damaged every year, and are used as various anti-corrosive paints to prevent corrosion of steel and nonferrous metal materials. Accordingly, various types of rust-preventive and nylon undercoat materials for the above materials are also researched and developed according to their purpose and properties.

The corrosion of metals is due to the action of air, water, carbon dioxide and heat. Therefore, the rust-preventive paint should have two functions to prevent contact with these and metal surfaces and to prevent chemical rust, and the top coating nylon coating should show sufficient adhesion. The paint has a vehicle structure in which organic parts of various resins, color pigments, and inorganic constitution parts are mixed.

Alkyd resins, polyester resins, acrylic resins, modified acrylic resins, epoxy resins, modified epoxy resins and urethane resins are used as the coating resin.

Among them, alkyd resins and modified alkyd resins are deteriorated in physical properties of the coating film itself when stored or coated and then exposed to the atmosphere, and have poor alkali resistance. In addition, the ester bond in the alkyd resin not only degrades adhesion to a special metal material, hydrophobic resistance, and chemical properties due to hydrolysis during storage, but also has a great possibility of color discoloration of the coating due to baking temperature. .

In addition, in the case of using a polyester resin type as a tape measure under the conventional tape coating, the physical properties of the cured coating film is excellent, but coating film aging phenomenon occurs when UV irradiation, which results in good adhesion of the UV ink and nylon adhesion depending on the amount of light. A lot of deviations occur and the coating of nylon film is applied within 3 ~ 5 seconds due to the strength of its own coating and the poor spreadability during coating.

The epoxy resin is used as a high molecular weight epoxy type epoxy resin. These epoxy resins have a problem in that the paint pigment dispersibility is lowered due to self-aggregation, resulting in poor workability due to high molecular weight and poor appearance of the coating film, and also causes poor adhesion of the nylon extrusion coating due to the too strong coating. In addition, there is a limitation that the pigment should not have a high oil absorption as well as a coloring pigment that can exhibit a high hiding power, and the final paint viscosity should not be high.

Accordingly, in consideration of the interlayer adhesion problem, corrosion resistance, chemical resistance, and workability problems of the nylon top coating of the conventional coating composition, the workability is improved, and the adhesion of various steel materials and special metal materials, chemical properties and rust resistance are improved. There is a need for a study on the development of a coating composition which improves the adhesion in the coating of the top coat nylon resin.

In addition, by selecting pigments that show sufficient concealment with a thin coating film, it is possible to improve the color dichroism due to lack of hiding power, improve color separation and work stability during continuous line work, and improve disadvantages such as settling problems due to high pigment content. There is a need for research on composition development.

The present invention is not only excellent in mechanical properties such as durability and corrosion resistance, chemical resistance, chemical resistance, etc., but also a rheological epoxy ester coating composition having excellent adhesion when coating UV curable paint on a cured coating film and extrusion coating of nylon resin, and its It is intended to provide a manufacturing method.

The present invention provides a rheological epoxy ester coating composition comprising a rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, a melamine resin having a number average molecular weight of 500 to 2,000, and a block isocyanate resin having a number average molecular weight of 300 to 20,000. to provide.

The present invention also relates to a) a rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, a polymer dispersing agent, and a pigment, followed by mixing; and b) a number average molecular weight of 500 to the mixture prepared from step a). It provides a melamine resin of 2 to 2,000, and a block isocyanate resin having a number average molecular weight of 300 to 20,000.

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

The present invention is characterized in that the rheological epoxy ester coating composition reacts with an epoxy ester resin to a melamine resin and a block isocyanate resin, so that the reaction occurs stepwise at a predetermined temperature to have an excellent adhesion when the nylon resin is extrusion coated onto the cured undercoat. It is done.

In particular, in one preferred embodiment of the invention, as shown in FIG. 1, the rheological epoxy ester coating composition of the present invention reacts only melamine resin to the epoxy ester resin or blocks isocyanate resin to the epoxy ester resin. In the case of the reaction, hardening does not proceed during the designated drying time, and thus the physical properties are weak. On the other hand, by reacting the melamine resin and the block isocyanate resin together with the epoxy ester resin at a predetermined temperature, for example, the first oven 140 ° C and the second oven 180 ° C. The reaction takes place in stages, and a chemical composition similar to that of the nylon resin is generated, thereby ensuring more effective adhesion with high affinity when extrusion coating the nylon resin on the cured undercoat.

In particular, in the case of reacting only melamine resin, the hardened coating film is hard, so it is difficult to adapt to the top nylon, and there is a problem in workability due to gas generation during the drying process and other chemical properties are inferior. On the other hand, when only the block isocyanate resin is reacted, the curing time is long, so that the specified curing conditions cannot be satisfied, and continuous operation is difficult.

The rheological epoxy ester coating composition of the present invention comprises a rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, a melamine resin having a number average molecular weight of 500 to 2,000, and a block isocyanate resin having a number average molecular weight of 300 to 20,000. do.

The rheology epoxy ester resin is to give flexibility to the baked epoxy ester coating composition of the present invention, the number average molecular weight of 500 to 20,000 is used, preferably 1,000 to 3,000 can be used. If the number average molecular weight is less than 500, a problem of brittleness of the final coating composition occurs, and if the number average molecular weight is more than 20,000, roll workability of a pickup roll or the like is deteriorated.

The rheological epoxy ester resin usable in the present invention is esterified by reacting an epoxy resin with a fatty acid, in particular the epoxy resin has an epoxy equivalent of 300 to 3,500, preferably 900 to 3,000, and a solid content of 50% or less, preferably It can be 45% or less. For example, epoxy YD 011, YD 014, YD 017, YD 019 resin, or the like can be used. There are many differences in the final properties and adhesion of nylon extrusion coating depending on the type of epoxy resin.

In addition, the fatty acid may be a fatty acid having 8 to 20 carbon atoms, preferably 8 to 18 carbon atoms, more preferably coconut fatty acid, dihydrate castor oil fatty acid, isononanoic fatty acid, soybean oil fatty acid, tall oil fatty acid Etc. can be used by 1 or more types.

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The rheological epoxy ester resin may have a whey of 30% to 45%, preferably 32% to 40%, and an acid value of 5 or less, preferably 3 or less. The whey indicates the amount of oil or fatty acid content (wt%).

The rheological epoxy ester resin may be included in an amount of 10 to 40 parts by weight, preferably 20 to 35 parts by weight, based on the total weight of the coating composition, and when the epoxy ester resin content is less than 10 parts by weight, there is a problem that the coating film hardness increases. It may occur, and if the content exceeds 40 parts by weight, it is not preferable to peel off like top coat nylon.

The coating composition of the present invention contains a melamine resin and a block isocyanate resin together with the rheology epoxy ester resin.

The melamine resin has a number average molecular weight of 500 to 20,000, preferably 600 to 1800. If the number average molecular weight is less than 500, mechanical properties may be degraded. If the number average molecular weight is more than 20,000, it is not preferable in terms of roll workability.

The melamine resin is used to improve the reactivity, paint chemical properties, adhesion, and rust resistance in the coating composition. The melamine resin may be one selected from the group consisting of hexamethylmethoxy melamine resin, partially alkylate melamine resin, alkylate carboxylate melamine resin, and mixtures thereof. The melamine

In another specific example of the invention, the melamine resin may be used hexamethoxy methylmelamine resin represented by the following formula (2).

[Formula 2]

The melamine resin may be included in an amount of 0.5 to 15 parts by weight, preferably 1 to 5 parts by weight, based on the total weight of the coating composition. If the content is less than 0.5 parts by weight, sufficient curing reaction of the coating may not occur, thereby deteriorating the physical properties of the coating. If it exceeds 15 parts by weight, the coating may be brittle and adhesion of the top coat may be reduced. These melamine resins can be selected differently depending on the workability and physical properties required by the demand line, such as compatibility with the main component resin, type of coating equipment, flexibility, coating strength, adhesion, drying properties.

In addition, the block isocyanate resin has a number average molecular weight of 300 to 20,000, preferably 350 to 2,000. If the number average molecular weight is less than 300, mechanical properties may be degraded. If the number average molecular weight is more than 20,000, it is not preferable in terms of roll workability.

The block isocyanate resin undergoes a reaction during the second heating to increase adhesion and chemical resistance to the top coat and to reduce formalin generation due to the use of melamine. As the block isocyanate resin, one or more selected from aliphatic block isocyanate and aromatic block isocyanate resin may be used. In addition, the block isocyanate resin may be used aliphatic block isocyanate.

In another specific example of the invention, the block isocyanate resin may use hexamethylene diisocyanate represented by the following formula (3).

(3)

The block isocyanate resin may be included in an amount of 1 to 10 parts by weight, preferably 3 to 7 parts by weight, based on the total weight of the total coating composition, and if the content is less than 1 part by weight, chemical resistance problems may occur. Undesirable drying is not preferred, which is undesirable.

In addition, as shown in FIG. 1, the coating composition of the present invention is a nylon resin (CONH) having a top coat by a polyurethane bond and a polyurea bond by stepwise reaction of hydroxyl groups, melamine and block isocyanates of a rheological epoxy ester resin, respectively. The chemical composition is similar to that of forming affinity, thereby ensuring excellent adhesion.

In a preferred embodiment of the present invention, the rheological epoxy ester coating composition has a number average molecular weight of 500 to 20,000 relative to the total weight of the total composition, 1 to 40 parts by weight of a rheological epoxy ester resin, number average molecular weight of 500 to 2,000 The melamine resin may include 0.5 to 15 parts by weight, and 1 to 10 parts by weight of the block isocyanate resin having a number average molecular weight of 300 to 20,000.

In addition, the coating composition of the present invention may further include a phenol noblock epoxy resin having a number average molecular weight of 190 to 2,500, preferably 190 to 1,000. The phenol noblock epoxy resin may increase the coating film acid resistance of the rheology epoxy ester baking coating composition and may affect adhesion with nylon. If the number average molecular weight is less than 190, the coating film becomes brittle, and if the number average molecular weight is more than 2,500, the coating film becomes stronger, causing a problem of poor UV ink adhesion.

In another specific example of the invention, the phenol noblock epoxy resin may be represented by the following formula (4).

[Formula 4]

In formula, n is 0.2-1.

The phenol noblock epoxy resin may be included in an amount of 1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on the total weight of the coating composition.

In addition, the rheological epoxy ester coating composition of the present invention may further include at least one polymer dispersant, pigment, anti-sedimentation agent, silane coupling agent, co-solvent, antiseptic agent and the like.

The polymer dispersant may be any dispersant known to be usable in the coating composition, and is not particularly limited to the kind thereof.

Since pigments affect color, hiding power and workability, it is important to maintain an appropriate content range in the paint composition. Preferably, in the present invention, the coloring and sieving pigment is included in the content of 10 to 50% by weight, preferably 20 to 40% by weight in the total coating composition. If the content of the pigment is less than the above range, a sufficient concealing effect cannot be obtained, and if it exceeds the above range, the dispersion and stability of the coating composition are lowered.

In this case, the pigment should be used for products with low oil absorption and excellent weather resistance, and the use of some organic pigments can reduce the total amount of pigment used.

Meanwhile, the rheological epoxy ester coating composition of the present invention includes two pigments selected from the group consisting of soluble low toxicity pigments, coloring and sieving pigments, and mixtures thereof.

 The coloring and sieving pigments may be selected from the group consisting of isoindolin, titanium dioxide, carbon black, barium sulfate, calcium carbonate, mica, talc and mixtures thereof. Such pigments may be appropriately selected by those skilled in the art according to the intended use of the rheological epoxy ester coating composition of the present invention. The pigment comprises 10 to 50% by weight, preferably 20 to 40% by weight of the total coating composition. More specifically, the coloring pigment is used in 20 to 40% by weight. If the content is less than the above range, the problem of concealment and adhesion of the UV ink is poor, and if the content exceeds the above range, there is a problem of insufficient chemical resistance and adhesion of the material.

The colored pigment may be one or two selected from the group consisting of talc, silica, barium sulfate, calcium carbonate, mica, and mixtures thereof, such as ceramic and isoindolin yellow, titanium dioxide colored pigment, and extender pigment.

In addition, the relative weight ratio (pigment and sieving powder) / (resin powder) of the resin composition (weight component) and the coloring and sieving pigment of the present invention may be 1.75 to 1.95, preferably 1.8 to 1.9. When the relative weight ratio is less than 1.75, appearance defects may occur due to the lack of hiding power at 10 microns when the roll coat is applied, and when it exceeds 1.95, the concealment and workability may be good, but coating properties and nylon adhesion may be degraded. have.

It is preferable to maintain the final coating gloss within 40% to 60% when measuring 60 ㅀ mirror gloss by using the coloring and sieving pigments, and when exceeding 60%, printing scale adhesion defect may occur during UV printing, and more than 40% In small cases, poor coating of nylon and UV prints may occur due to reduced coating hardness.

Also, The rheological epoxy ester coating composition according to the present invention may further include a sedimentation inhibitor. Since the pigments described above are heavy, the specific gravity is in the range of 2 to 5, the pigment may precipitate during the storage of the paint, resulting in deterioration of physical properties of the coating composition or poor workability. Antisettling agents are used to prevent the precipitation of pigments, and fume silica, organocray, bentonite, aerogel 300 ^® , bentonite, aerogel 972 ^® , creton ^® , benton 27 ^® , benton 34 ^® and benton 38 ^® And one selected from the group consisting of a mixture thereof.

The anti-settling agent may be included in an amount of 0.1 to 10 parts by weight, preferably 2 to 7 parts by weight, based on the total weight of the total coating composition. If the content is less than 0.1 parts by weight, it is difficult to suppress the precipitation of the pigment, and if it exceeds 10 parts by weight, the appearance defects due to poor wetting and the cost increase economically, it is preferable to use properly within the above range Do.

Solvents that can be mixed well with the resin used are used, and affects the coating workability and paint properties such as coating appearance, foaming, paint spreading, drying properties. The solvent may be 2 to 3 selected from the group consisting of lower alcohols, ethers and ketone mixtures having evaporation boiling points belonging to 100 to 300 ° C. Typically, one lower alcohol selected from the group consisting of butyl alcohol, isobutyl alcohol, isopentyl alcohol, isopropyl alcohol, and a combination thereof, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether acetate ( Cellosolve acetate), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether, propylene glycol monomethyl ether, diacetone alcohol, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, ethylene glycol butyl One ether selected from the group consisting of ether acetate, 3-methyl 3-methoxybutanol and mixtures thereof, and a mixed solvent thereof is possible. Preferably, butyl cellosolve, diacetone alcohol, methyl ethyl ketone (MEK), or the like may be used as the solvent, and toluene, xylene, or the like may be used as the co-solvent.

The co-solvent includes 10 to 50 parts by weight, preferably 20 to 40 parts by weight of the total coating composition. If the content is less than the above range, there is a problem of lack of bubble generation and coating gloss, and if the content exceeds the above range, concealment defects and flow phenomena occur.

In another preferred embodiment of the invention, the rheological epoxy ester coating composition according to the present invention is an epoxy ester resin, a phenol noble epoxy resin, a block isocyanate resin, a hexamethylmethoxy melamine resin and a polymer dispersant, a pigment sedimentation inhibitor, a co-solvent and Can contain a stimulant.

In addition, the rheology-epoxy ester coating composition is 10 to 40 parts by weight of rheology epoxy ester resin, 0.5 to 15 parts by weight of melamine resin, 1 to 10 parts by weight of block isocyanate resin, phenol noble epoxy resin 1 relative to the total weight of the total composition To 20 parts by weight, 0.05 to 10 parts by weight of the polymer dispersant, 10 to 50 parts by weight of the pigment, 0.1 to 10 parts by weight of the anti-settling agent, 10 to 30 parts by weight of the co-solvent, and the remainder of the true solvent.

Such a rheological epoxy ester coating composition may further comprise one to three selected from the group consisting of a reaction accelerator, a material spreading aid, an antifoaming agent, a surface control agent, a surface spreading aid, a rust preventive and adhesion promoter, a combination thereof as necessary. have.

The reaction accelerator is for enhancing the curability of the melamine resin, and improves workability according to the temperature of the paint reactant, and satisfies the rust resistance, chemical resistance, and drying property required by the consumer. The reaction promoter may be one selected from the group consisting of para-toluene sulfonic acid, dinonylnaphthalene disulfonic acid, and mixtures thereof. The reaction promoter may be included in an amount of 0.1 to 5 parts by weight based on the total weight of the paint composition.

The antifoaming agent prevents bubbles and controls the surface tension of the paint and removes large and small bubbles that may be generated during the painting operation. If the bubble is not completely removed, the coating performance, such as durability, corrosion resistance and water resistance, as well as damage to the appearance of the coating, is degraded, which significantly affects the coating performance. The surface modifiers and surface spreading aids are those known in the art to prevent spreading, foaming, surface conditioning and cratering.

The rust preventive and adhesion enhancer improves rust preventive and material adhesion in order to enhance the adhesion of materials affecting the final coating performance. The antirust and adhesion promoters are those known in the art, and are typically titanium tetra butannolate polymer, methoxy or ethoxy silane coupling aid (vinyl group, epoxy group, amino group, methacryl group). One selected from the group consisting of a combination of these is possible. The content of the rust preventive and adhesion promoters may be used in an amount of 0.1 to 5 parts by weight based on the total weight of the total coating composition.

The antifoaming agent, surface conditioner, surface spreading aid, and the like give a lot of influence on the adhesion when extruded nylon coating, the coating composition of the present invention does not affect the roll coating by maintaining the appropriate surface tension even without using these agents 30 dyne / cm can be maintained, and at this time, it is not possible to use a product that exhibits many effects on surface control, such as silicone or acrylic, and some of vinyl polymer formulations may be used.

On the other hand, the present invention provides a process for producing the rheological epoxy ester coating composition. The production method includes the steps of: a) adding a rheology epoxy ester resin having a number average molecular weight of 500 to 20,000, a polymer dispersant, and a pigment, and b) adding a number average molecular weight of 500 to the mixture prepared from step a). Mixing a melamine resin of 2,000 and a block isocyanate resin having a number average molecular weight of 300 to 20,000.

It may further comprise the step of grinding the mixture prepared from step a).

In addition, in step b), a phenol noblock epoxy resin having a number average molecular weight of 190 to 2,500 may be further added, and at least one of an antisettling agent, a silane coupling agent, a coarse solvent, a scavenger, and the like may be further added.

In particular, in one preferred embodiment of the invention, the epoxy ester coating composition is i) adding a rheological epoxy ester resin dispersant and pigments to the reactor and uniformly mixed, WETTING step on the pigment surface, ii) of step i) Stirring the mixture at high speed to disperse the mixture, iii) adding the phenol noble epoxy resin, melamine resin, block isocyanate resin, co-solvent and solvent to the mixture of step ii) and mixing the mixture uniformly.

As a result, the prepared rheological epoxy ester coating composition had a viscosity of 75 to 125 ku, measured by a Crebes-stopper viscometer, a gloss of 45 to 60% of the coating film, and a particle of 12.5 to 18 μm.

The rheological epoxy ester coating composition prepared in this manner is excellent in corrosion resistance and chemical resistance and is preferably applied for nylon extrusion coating undercoat.

The coating composition has excellent initial water resistance and corrosion resistance even when coated with a small thickness. In addition, the composition is excellent in dispersibility and storage stability, it is difficult to disperse pigments in the conventional epoxy system and the alkali resistance which is a defect of the polyester type is characterized by improved corrosion resistance. In addition, the storage stability is excellent while maintaining the baking work stability.

In the present invention, matters other than those described above can be added or subtracted as necessary, and therefore the present invention is not particularly limited.

The rheological epoxy ester coating composition according to the present invention forms a coating film on the surface of the material to impart mechanical and chemically excellent physical properties including corrosion resistance. It is possible to extend the durability and service life of the tape measure product by maintaining excellent adhesion when coating nylon resin with excellent UV printing and abrasion resistance, thereby increasing the competitiveness of the product.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Examples 1-3 and Comparative Examples 1-3

To the coating composition was prepared in a composition as shown in Table 1 below.

First, a rheological epoxy ester resin or an epoxy resin or a polyester resin, a polymer dispersant, and an antisettling agent were added to the reactor, and then stirred at a speed of 1200 rpm for 10 minutes with a stirrer. Stirring was carried out until the particles of the mixture was 50 ~ 60 ㎛, color pigments and sieving pigments were added thereto for 10 minutes high speed stirring at 1,200 rpm and then maintained by using a sand mill to a final particle size of 20 ㎛ or less.

Next, a noblocphenol epoxy resin, a block isocyanate resin, a melamine resin, a reaction promoter, and an adhesion promoter were added to the reactor and stirred at a speed of 1000 rpm for 30 minutes. After stirring, a thick solvent and a cosolvent were added to prepare a composition having a viscosity of 80 to 90 ku.

The content of each composition for the coating compositions of Examples 1 to 4 and Comparative Examples 1 and 2 is as shown in Table 1 below. The unit is weight percent.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy Resin ¹ 40 38 Epoxy Ester ² 33 Epoxy Ester ³ 33 33 Polyester resin ⁴ 40 Essence ⁵ 5 5 5 5 5 5 Constitutional Pigments ⁶ 5 5 5 5 5 5 Pigment Pigment ⁷ 35 35 35 34 35 35 Antisettling agents ⁸ One One One 2 One One Polymeric dispersants ⁹ One One One One One One Phenolic Noble Epoxy Resin ¹⁰ 3 3 3 0 3 Melamine resin ¹¹ 3 3 3 5 5 4 Block Isocyanate ¹² 2 2 2 One 2 Reaction accelerators ¹³ 0.5 0.5 0.5 0.5 0.5 0.5 Antifoam ¹⁴ 0.1 0.1  0.1 0.1 Material spreadability preparation ¹⁵ 0.2 0.1 0.2 0.2 Solvents ¹⁶ 6 6 6 5 3 3 Cyanide ¹⁷ 5 5 5 2 3 One Surface conditioners ¹⁸ 0.1 Pigment ratio / resin ratio (solid) 1.85 1.85 1.85 1.74 1.65    1.74 week)
1: high molecular weight epoxy resin: number average molecular weight 500 to 20,000, light synthesis resin
2: epoxy ester resin: number average molecular weight 500 to 20,000, crude synthetic resin
3: epoxy ester resin: number average molecular weight 500 to 20,000 dimming self-synthetic resin
4: polyester: number average molecular weight 500 to 20,000 synthetic resin
5: solvent: diacetone alcohol, butyl cellulsolve, methyl ethyl ketone
6: Sieving Pigments: Talc, Fumed Silica
7: Pigmented Pigment: TiO ₂ + Ceramic, Isoindolin Yellow
8: sedimentation inhibitor: Benton products
9: high molecular weight dispersant: high molecular weight block copolymer with pigment affinity functional group
10: phenol noble epoxy: national chemical number average molecular weight 190 to 2,500
11: Melamine resin: hexamethylmethoxy modified melamine, CYMEL 303 Cytec products
12: block isocyanate resin
13: Reaction accelerator: Block Acid PTSA denaturation, King Industries
14: Defoamer:
15: Material spreadability preparation: polyether modified polydimethylsiloxane liquid, acrylic copolymer
16: Solvents: Xylene, Toluene
17: Antiseptics: organic ketones (MIBK, MEK), diacetone alcohol
18: Surface conditioner: BYK 310, BYK358

Experimental Example

In order to measure the physical properties of the coating composition prepared in Examples 1 to 3 and Comparative Examples 1 to 3, after the cold-rolled steel sheet (KS D 3512) and iron phosphate-based pretreatment was applied to a bar coating to a thickness of 10 ~ 15 ㎛ After setting for 10 seconds, after adjusting the surface temperature of the material to reach 220 ℃ in the PMT drying furnace to prepare a test piece, and measured the respective physical properties in the following manner.

Nonvolatile matter (%)

After the sample was taken, the initial sample weight was measured, followed by hot air drying at 105 ° C. for 3 hours, and the weight of volatile matter relative to the initial sample weight was calculated based on Equation 1 below.

[Equation 1]

Nonvolatile matter (%) = ((Initial sample weight-weight of volatile) / Initial sample weight) × 100

Viscosity (Ku)

It measured using the Stormer viscometer at 25 degreeC.

Particle size (㎛)

It was measured with a particle size meter.

Dry state (MEK property)

After baking at the prescribed temperature of 220 ° C. × 60 seconds, methyl ethyl ketone was applied to a cotton cloth and rubbed with a dry film of 1 kgf.

(Circle): There is no phenomenon which comes out after ten times.

(Triangle | delta): It rubs a little after rubbing 7-8 times.

X: It is buried after rubbing 3-4 times.

Painting workability (bar coat & spray coating state)

The dry coating thickness was coated with a thickness of 15 µm and visually compared to obtain a smooth coating thickness, and then divided into three stages of good (○), good (△) and bad (×).

Pencil hardness (MITSU-BISHI)

Sharpen the tip of the Mitsubishi UNIT pencil so that the core is 4 ± 1mm, apply the core to the abrasive paper at right angles, polish it in a circle, make the end smooth and sharp, and 1kgf at a 45 ° angle with the coating surface. I drew five lines of 5cm or more in front of the force. At this time, the test site was erased with an eraser and then the scratches were visually observed. The hardness of the coating film was determined when there were no more than three scratches among the five lines.

Adhesive

According to the cross-cut test method of ASTM D 3359, the cut made to the specimen was cut with a sheath and adhered to the cellophane tape so that the scratched part was evenly attached. Next, the peeling state of the coating film of the site | part where the cellophane tape was peeled off and a scratch was compared visually, and it divided and evaluated as follows.

(Circle): No peeling.

(Triangle | delta): 80% or more of coating film remainder.

X: 50% or less coating film remaining.

Impact Resistance (Dupont, 1/2 "* 500g * 30cm)

Dupont impact tester was used to measure the cracks on the specimens produced in the size of 1/2 "× 500g × 30㎝, and according to the crack condition, there were three stages of good (○), good (△) and bad (×). Judgment was made separately.

Salt spray

Specimens made according to ASTM B117 were made with X-shaped lines according to method 2 (scraping method) of ASTM D1654. Subsequently, according to KS D 9502, a 5% NaCl aqueous solution was exposed to a salt spray machine sprayed at 35 ° C. to expose the time, and the state of the coating film was examined as follows.

○: 1 mm or less on one side.

(Triangle | delta): 1-2 mm.

X: 2 mm or more.

Top coat adaptability (alkyd type, epoxy type, urethane type paint)

After each coating composition was left for 1 day after the top coat, it was determined by dividing it into three stages of good adhesion (○), good (△), and poor (×) to alkyd, urethane, and epoxy systems.

Flexibility (180 degree banding)

The coating film surface of the specimen was bent inward by 180 ° and adhered with a cellophane tape to determine whether the coating film was peeled off.

(Circle): It is not peeled at all.

(Triangle | delta): A part of bending part peels off.

X: The bend part completely peeled off.

Zhejiang

Each paint composition was stored at 40 ° C. for 1 month, and then the precipitation state of the paint composition was checked to see if a hard precipitate occurred:

○: no precipitate at all.

(Triangle | delta): A slight precipitate.

X: A large amount of precipitates are generated.

Alkali resistance

According to KSM-5000-3411, the specimen was immersed in 10% aqueous NaOH solution for 48 hours according to the immersion resistance test method of dry coating film, and then measured by bristering or 60 ㅀ mirror gloss to obtain excellent (○) or good (△) It determined by dividing into three steps of defect (x).

Acid resistance

According to KSM-5000-3411, the specimen was immersed in 5% HCL aqueous solution for 48 hours according to the test method for immersion resistance of dry coating film, and then measured by bristering or 60 ㅀ mirror gloss to obtain excellent (○) or good (△) It determined by dividing into three stages of defect (x).

Acetic Acid Resistance

According to KSM-5000-3411, the specimen was immersed in 5% aqueous CH ₃ COOH solution for 48 hours according to the immersion resistance test method of dry coating film, and then measured by bristering or 60 ㅀ mirror gloss to obtain excellent (○) or good ( (Triangle | delta)) and it divided into three stages of defect (x), and it determined.

Nylon extrusion adhesiveness

Using a designated extrusion coating machine, cool the melted nylon at 220 ° C by coating a 30cm extruder at a speed of 20 m / min on the undercoated tape measure under vacuum, and then check the adhesion between the coated undercoat and nylon. It measured and divided into three stages, good ((circle)), good (triangle | delta), and bad (x), and determined.

The measurement results of the physical properties of the specimens of Examples 1 to 3 and Comparative Examples 1 to 3 are as shown in Table 2 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Nonvolatile matter (%) 65 65 65 63 65 65 Viscosity (Ku25 ℃, Stormer Viscometer) 80 80 80 75 85 83 Particle size (㎛) 20 20 20 20 20 20 Dry state (MEK property) ○ ○ ○ ○ ○ ○ Painting workability ○ ○ ○ ○ △ △ Pencil Hardness (MITSUBISHI) 3H4H 4H5H 4H5H 4H5H 5H6H 5H6H Material adhesiveness ○ ○ ○ ○ ○ ○ Impact Resistance (Dupont, 1/2 "* 500g * 30) ○ ○ ○ ○ ○ ○ Salt spray ○ ○ ○ ○ ○ ○ Acetic Acid Resistance ○ ○ ○ ○ ○ ○ Flexibility (180 ° Banding) ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ △ △ △ ○ Alkali resistance ○ ○ ○ ○ ○ ○ Nylon adhesion △ ○ △ × × ×

As shown in Table 2, it can be seen that the coating compositions of Examples 1 to 3 according to the present invention are excellent in workability, durability, coating hardness, mechanical properties, corrosion resistance, material adhesion, and top coat adhesion.

On the other hand, in the case of Comparative Example 1 using the existing polyester resin, it can be seen that the nylon adhesion is significantly reduced to 'poor', which is not suitable as a prima. In addition, in the case of Comparative Examples 2 and 3 using an epoxy resin instead of the epoxy ester resin of the present invention, not only this nylon adhesion is not good, but also the paintability is remarkably inferior, indicating that the mechanical and chemical properties are not good.

1 is a graph showing the step-by-step curing reaction at a constant temperature through the RPT 3000 curing reaction meter of the rheological epoxy ester resin, melamine resin, block isocyanate resin according to an embodiment of the present invention.

Claims (15)

Rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, Melamine resin having a number average molecular weight of 500 to 2,000, and Block Isocyanate Resin with Number Average Molecular Weight 300 to 20,000 Rheological epoxy ester coating composition comprising a. The method of claim 1, The rheology epoxy ester resin has a whey of 30% to 45%, an acid value of 5 or less rheology epoxy ester coating composition. The method of claim 1, The rheological epoxy ester resin composition is an epoxy equivalent of 300 to 3,500, an epoxy resin having a solid content of 50% or less and obtained from a fatty acid having 8 to 20 carbon atoms. The method of claim 3, The fatty acid may be at least one selected from the group consisting of coconut fatty acid, dihydrate castor oil fatty acid, isononanoic fatty acid, soybean oil fatty acid, and tall oil fatty acid. The method of claim 1, The melamine resin is at least one selected from the group consisting of hexamethyl methoxymelamine resin, partially alkylate melamine resin, alkylate carboxylate melamine resin, butoxymelamine resin, and mixtures thereof. The method of claim 1, The block isocyanate resin is an aliphatic block isocyanate rheological epoxy ester coating composition. The method of claim 1, Regarding the total composition total weight, 1 to 40 parts by weight of the rheology epoxy ester resin, 0.5 to 15 parts by weight of the melamine resin, and 1 to 10 parts by weight of the block isocyanate resin Rheological epoxy ester coating composition comprising a. The method of claim 1, A rheological epoxy ester coating composition further comprising a phenol noblock epoxy resin having a number average molecular weight of 190 to 2,500. The method of claim 8, A rheological epoxy ester coating composition comprising the phenol noblock epoxy resin in an amount of 1 to 20 parts by weight based on the total weight of the total composition. The method of claim 1, A rheological epoxy ester coating composition further comprising at least one member selected from the group consisting of a polymer dispersant, a pigment, an antisettling agent, a silane coupling agent, a co-solvent, and a true solvent. The method of claim 1, About the total weight of the total composition 10 to 40 parts by weight of a rheology epoxy ester resin, 0.5 to 15 parts by weight of melamine resin, 1 to 10 parts by weight of a block isocyanate resin, 1 to 20 parts by weight of a phenol noblock epoxy resin, 0.05 to 10 parts by weight of a polymer dispersant, 10 to 40 parts by weight of the pigment, 0.1 to 10 parts by weight of antisettling agent, 10-30 parts by weight of a cosolvent, and Balance Agent Rheological epoxy ester coating composition comprising a. a) adding and mixing a rheological epoxy ester resin having a number average molecular weight of 500 to 20,000, a polymer dispersant, and a pigment, and b) mixing a melamine resin having a number average molecular weight of 500 to 2,000 and a block isocyanate resin having a number average molecular weight of 300 to 20,000 in the mixture prepared from step a). Method of producing a rheological epoxy ester coating composition comprising a. The method of claim 12, Method for producing a rheological epoxy ester coating composition further comprising the step of grinding the mixture prepared from step a). The method of claim 12, In the step b), the number average molecular weight of 190 to 2,500 is a method for producing a rheological epoxy ester coating composition further adding a phenol noblock epoxy resin. The method of claim 12, Method of producing a rheological epoxy ester coating composition further comprising at least one selected from the group consisting of anti-settling agent, silane coupling agent, co-solvent, and anti-solvent in step b).

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