KR102479765B1 - Acrylic-moified alkyd resin and coating composition comprising the same - Google Patents

Abstract

The present invention relates to an acrylic-modified alkyd resin and a rust-preventive coating composition comprising the same, wherein the acrylic-modified alkyd resin is prepared from a resin composition containing acid monomers and alcohol monomers including fatty acids, acid anhydrides, and monovalent or more basic acids. It is prepared using 45-85 parts by weight of styrene monomer based on 100 parts by weight of the alkyd resin.

Description

Acrylic modified alkyd resin and coating composition containing the same {ACRYLIC-MOIFIED ALKYD RESIN AND COATING COMPOSITION COMPRISING THE SAME}

The present invention relates to an acrylic-modified alkyd resin and a paint composition containing the same.

Alkyd resins are high molecular materials synthesized by the condensation of polyhydric alcohols and polyhydric acids. These alkyd resins have excellent anti-rust properties and have been used as components of anti-rust paint compositions for preventing surface corrosion of metal products such as steel pipes. However, there was a problem in that workability and productivity were lowered during drying of the coating film due to low room temperature curability of the alkyd resin.

In order to solve this problem, attempts have been made to improve physical properties such as curability and rust prevention of the resin by modifying the alkyd resin, such as an acrylic modified alkyd resin. However, conventional acrylic-modified alkyd resins are still low in normal temperature curing property, and thus, the room temperature touch drying property and fixed drying property of the anticorrosive coating composition are low. Therefore, there is a demand for the development of a new acrylic-modified alkyd resin having excellent anti-corrosion properties and curability at room temperature.

The present invention provides an acrylic-modified alkyd resin having excellent rust resistance and room temperature curing properties.

In addition, the present invention provides a rust-preventive paint composition containing the above-described acrylic-modified alkyd resin and excellent in rust-preventive properties and dryness at room temperature.

The acrylic modified alkyd resin of the present invention is an alkyd resin prepared from a resin composition containing acid monomers and alcohol monomers containing fatty acids, acid anhydrides, and monovalent or more basic acids in an equivalent ratio of 25-35: 55-60: 5-15. It is prepared using 45-85 parts by weight of styrene monomer per 100 parts by weight.

When the acrylic-modified alkyd resin of the present invention is included as one component of a rust-preventive paint composition, it is possible to improve rust-preventive properties and appearance characteristics of the paint composition, as well as touch-drying and fixed-drying properties at room temperature, without deterioration in compatibility with solvents.

Hereinafter, the present invention will be described in detail. However, it is not limited only by the following contents, and each component may be variously modified or optionally mixed as needed. Therefore, it should be understood to include all modifications, equivalents or substitutes included in the spirit and scope of the present invention.

<Acrylic Modified Alkyd Resin>

The acrylic-modified alkyd resin of the present invention is a copolymer synthesized by an addition reaction of an alkyd resin and a styrene monomer, and when applied to a paint composition, it can impart excellent rust prevention, water resistance, and room temperature drying property to the paint composition.

alkyd resin

The alkyd resin serves as the base of the acrylic modified alkyd resin, and is polymerized by an esterification reaction between an acid monomer and an alcohol monomer. In this case, the acid monomer includes a fatty acid, an acid anhydride, and a monovalent or more basic acid, and the alcohol monomer includes a C ₁ -C ₁₀ polyhydric alcohol.

These fatty acids are chain monocarboxylic acids, which lead to denaturation of alkyd resins. These fatty acids include unsaturated fatty acids, saturated fatty acids, and synthetic fatty acids. In the case of unsaturated fatty acids, since there is a double bond between carbons in the molecule, the alkyd resin can be denatured more effectively. Non-limiting examples of the unsaturated fatty acids include coconut oil, castor oil, grape seed oil, linseed oil, oiticica oil, and palm oil. ), palm kernel oil, safflower oil, sunflower oil, soya bean oil, tung oil, tall oil, dehydrated castor oil castor oil), etc., which may be used alone or in combination of two or more.

The acid anhydride is a type of polyhydric acid and is a raw material for alkyd resins. As the acid anhydride, any one commonly known in the art may be used without particular limitation. For example, phthalic anhydride, maleic anhydride, tetra hydro phthalic anhydride, chlorendic anhydride, acetic anhydride, acetic benzoic anhydride, succinic anhydride, glutaric acid There are acid anhydrides, benzoic acid anhydrides, etc., but it is not limited thereto. These may be used alone or in combination of two or more.

The monovalent or more basic acid is a kind of acid containing at least one carboxyl group in the molecule, and is not particularly limited as long as it is a monovalent or more aromatic or aliphatic acid commonly known in the art. For example, adipic acid, sebacic acid, oxalic acid, malonic acid, malic acid, fumaric acid, maleic acid , succinic acid, sebacic acid, glutaric acid, aspartic acid, tartaric acid, pimelic acid, suberic acid, Monovalent or more valent groups such as citric acid, isocitrate, aconitic acid, propane-1,2,3-tricarboxylic acid, etc. aliphatic base acids (eg, divalent or trivalent aliphatic base acids); Benzoic acid, p-tert-butylbenzoic acid (PTBBA), phthalic acid, iso-phthalic acid, dimethylisophthalic acid, benzene-1,3,5 -1 such as benzene-1,3,5-tricarboxylic acid, 5-sulfo-1,2,4-benzenetricarboxylic acid, etc. There are polyvalent or more aromatic base acids (eg, monovalent or trivalent aromatic base acids), etc., but are not limited thereto. These may be used alone or in combination of two or more.

According to one example, the monovalent or more basic acid may include an aliphatic base acid (eg, adipic acid) and an aromatic base acid (eg, benzoic acid, phthalic acid, etc.). In this case, the mixing ratio of the aliphatic base acid and the aromatic base acid may be 1-2:1 by weight.

In the present invention, the fatty acid, acid anhydride and monovalent or more basic acid are mixed and used in an equivalent ratio of 25-35 : 55-60 : 5-15. By using the acid monomers mixed in the equivalent ratio, room temperature curing without gelation of the resin is prevented from deterioration in the compatibility of the resin with organic solvents (eg, xylene, toluene) due to the increase in the acrylic modification rate of the acrylic modified alkyd resin. can be further improved.

In the alkyd resin of the present invention, the alcohol monomer includes a C ₁ -C ₁₀ polyhydric alcohol. The C ₁ -C ₁₀ polyhydric alcohol is an alcohol having a high molecular weight and can be ester-bonded with an acid monomer to improve the flexibility of the resin, as well as improve room temperature dryness and hardness of the resin.

Non-limiting examples of the C ₁ -C ₁₀ polyhydric alcohol include C ₁ -C ₁₀ dihydric alcohols such as neopentyl glycol and 1,6-hexanediol; C ₁ -C ₁₀ trihydric alcohols such as trimethylol propane, trimethylol ethane, and 1,2,6-hexanetriol; C ₁ -C ₁₀ tetrahydric alcohols such as pentaerythritol, diglycerol, and sorbitol; C ₁ -C ₁₀ 5-6 alcohols such as mannitol and dipentaerythritol may be used alone or in combination of two or more.

According to one example, the C ₁ -C ₁₀ polyhydric alcohol includes a C ₁ -C ₁₀ trihydric alcohol (eg, trimethylol propane) and a C ₁ -C ₁₀ tetrahydric alcohol (eg, pentaerythritol). . In this case, compatibility, heatability, drying property, hardness, and the like of the resin may be improved. The mixing ratio of the C ₁ -C ₁₀ trihydric alcohol and the C ₁ -C ₁₀ tetrahydric alcohol is not particularly limited, and may be, for example, 1-3:1 by weight. When the mixing ratio of the C ₁ -C ₁₀ trihydric alcohol and the C ₁ -C ₁₀ tetrahydric alcohol is in the above-described range, compatibility and room temperature drying property of the resin may be further improved.

The equivalent ratio of the acid monomer and the alcohol monomer described above is not particularly limited, and may be, for example, 1: 1-1.5, in another example 1: 1-1.2. When the equivalent ratio of the acid monomer and the alcohol monomer is within the aforementioned range, physical properties such as rust prevention and adhesion of the resin may be improved.

The alkyd resins of the present invention can be prepared through methods known in the art. For example, an alkyd resin may be prepared by mixing a fatty acid, an acid anhydride, a monovalent or higher basic acid, and a C ₁ -C ₁₀ polyhydric alcohol, followed by heating, stirring, and a reflux reaction by introducing a solvent. At this time, the reaction conditions (temperature, time, stirring speed, etc.) are as known in the art.

The solvent necessary for the production of the alkyd is added for reflux to control the viscosity of the resin and smoothly remove the water (condensate) generated during the reaction and the smooth reaction of the resin. Non-limiting examples of the usable solvent include aromatic organic solvents such as toluene and xylene, dimethyl carbonate, and heptane. The content of the solvent varies depending on the viscosity of the resin and the like, and may be, for example, in the range of about 25-40% by weight based on the total amount of acid monomer, alcohol monomer and solvent.

In preparing the alkyd resin, an esterification reaction catalyst may be used to smoothly proceed the esterification reaction. For example, there is a tin compound (eg, dibutyl tin oxide, AP-CAT 0041, PC-4101, etc.), but is not limited thereto. The content of the reaction catalyst is not particularly limited and may be in the range of about 0.005-0.02% by weight based on the total weight of the acid monomer, alcohol monomer, solvent and catalyst.

The above-described alkyd resin may have an acid value in the range of 0-15, a solid content in the range of 50-70% by weight, and a weight average molecular weight in the range of 30,000-50,000. These alkyd resins can further improve curability at room temperature without gelation of the resin, while preventing deterioration in the compatibility of the acrylic-modified alkyd resin. The oil length of the alkyd resin is not particularly limited, and may range, for example, from about 30 to 60%, for example, from about 40 to 50%. When the whey of the alkyd resin is within the above range, room temperature drying properties and flexibility of the resin may be improved.

styrene monomer

In the acrylic modified alkyd resin of the present invention, the styrene monomer not only imparts physical properties of the acrylic resin to the alkyd resin, but also improves gloss, water resistance, drying property, impact resistance, and chemical resistance of the resin. In particular, drying property at room temperature can be improved through the effect of increasing the glass transition temperature (Tg) of the coating film.

In the present invention, the content of the styrene monomer is adjusted in the range of 45-85 parts by weight relative to 100 parts by weight of the alkyd resin. When the styrene monomer is used in the above amount, it is possible to improve the drying property of the acrylic modified alkyd resin and at the same time prevent a decrease in compatibility.

If necessary, in addition to the above-mentioned styrene monomer, an alkyl (meth)acrylate-based monomer, a vinyl toluene monomer, and the like may be further included. The alkyl (meth)acrylate-based monomer may improve weather resistance, chemical resistance, hardness, and the like of the resin. Non-limiting examples of such alkyl (meth) acrylate-based monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl ( There are meth) acrylate, cyclohexyl (meth) acrylate, etc., which may be used alone or in combination of two or more. The content of these additional monomers is not particularly limited, and may be, for example, in the range of about 20 to 50 parts by weight based on 100 parts by weight of the alkyd resin.

The above-described acrylic-modified alkyd resin may be prepared by adding a styrene monomer, a solvent, and an initiator to the alkyd resin, followed by an addition reaction between the alkyd resin and the styrene monomer through a conventional method. As the manufacturing method, there are a total amount input method and a monomer dropping method. For example, an alkyd resin and part of the solvent are first introduced into the reactor, the temperature of the contents is adjusted to about 130-150 ° C, and then the mixture of styrene monomer and initiator is added dropwise for about 2-3 hours, and then the initiator is additionally added. After maintaining the reaction by adding the mixture, an acrylic modified alkyd resin can be produced by diluting with a solvent to terminate the reaction.

An initiator usable in the present invention is not particularly limited as long as it is an initiator known in the art. For example, peroxide-based initiators may be used, and examples thereof include ditert butyl peroxide, cumyl hydroperoxide, t-butyl hydroperoxide, and benzoyl peroxide. oxide (benzoyl peroxide) and the like, but are not limited thereto.

The content of the initiator is not particularly limited, and may be, for example, in the range of about 1-5 parts by weight based on 100 parts by weight of the alkyd resin.

The solvent usable in the present invention is not particularly limited as long as it is commonly used in the art. For example, there are aromatic hydrocarbon solvents such as xylene and toluene, ester solvents such as butyl acetate and ethyl acetate, and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone. Two or more types may be mixed and used.

The amount of the solvent is not particularly limited, and may range, for example, from about 2.5 to about 8 parts by weight based on 100 parts by weight of the alkyd resin.

The aforementioned acrylic-modified alkyd resin may have an acid value in the range of 0-15, solid content in the range of 40-60% by weight, whey in the range of 25-40%, and weight average molecular weight in the range of 50,000-100,000. These acrylic-modified alkyd resins are excellent in anti-corrosion properties and also in room temperature curing properties. Accordingly, when the acrylic-modified alkyd resin of the present invention is included as one component of the anti-rust coating composition, the touch-drying property and fixed drying property of the coating film can be improved under curing conditions at room temperature. As a result, it is possible to economically dry the coating film naturally without a separate device such as a hot air blower.

<Rust-preventive paint composition>

The present invention provides a rust-preventive coating composition comprising the above-mentioned acrylic-modified alkyd resin. The anticorrosive coating composition according to the present invention includes the acrylic modified alkyd resin and, if necessary, may further include at least one selected from the group consisting of a solvent, an anticorrosive pigment, and an additive.

In the anticorrosive coating composition of the present invention, the content of the acrylic modified alkyd resin is not particularly limited and can be adjusted according to the viscosity of the coating composition. For example, when the paint composition of the present invention includes an acrylic-modified alkyd resin and a solvent, the content of the acrylic-modified alkyd resin may be in the range of about 20-70% by weight based on the total weight of the composition. As another example, when the paint composition of the present invention includes an acrylic-modified alkyd resin, an anticorrosive pigment, an additive, and a pigment, the content of the acrylic-modified alkyd resin may be in the range of about 20-60% by weight based on the total amount of the composition. .

In the paint composition of the present invention, the solvent adjusts the viscosity of the paint composition, and is not particularly limited as long as it can be easily volatilized during drying of the paint film. Organic solvents can be used as such solvents, and examples of the organic solvents include ketone solvents, ester solvents, ether solvents, hydrocarbon solvents, alcohol solvents, or mixtures thereof.

The content of the solvent is not particularly limited, and may be the remaining amount adjusted so that the total amount of the coating composition is 100% by weight.

In the paint composition of the present invention, a rust-preventive pigment may be added to improve corrosion resistance and durability. The anticorrosive pigment that can be used is not particularly limited as long as it is commonly known in the art. For example, there are zinc phosphate, aluminum triphosphate, phosphosilicate, calcium-modified silica, chromate, etc., but is not limited thereto. These may be used alone or in combination of two or more.

The content of the rust-preventive pigment is not particularly limited, and may be, for example, in the range of about 3-15% by weight based on the total weight of the composition. When the content of the rust-preventive pigment is within the above range, corrosion resistance and durability may be improved without affecting the viscosity of the coating composition.

If necessary, the coating composition of the present invention may further include extender pigments and/or color pigments in addition to the rust-preventive pigments described above.

As the extender pigment, any one known in the art may be used without particular limitation, and examples thereof include talc, mica, hard carbon CaCO ₃ , Al ₂ O ₃ SiO _{2 ,} MgO SiO ₂ and the like. The content of the extender pigment may be added to the paint composition in an amount known in the art, for example, in the range of about 1-10% by weight based on the total amount of the composition. When the content of the extender pigment is within the above-mentioned range, durability, touch-drying property, etc. of the coating composition may be improved without deterioration in adhesion, hot water resistance, and corrosion resistance of the coating film.

Any color pigment known in the art may be used without particular limitation, for example, titanium oxide, carbon black, iron oxide red, precipitated barium sulfate, calcium carbonate, kaolin, mica, aluminum, chromium oxide, There are cobalt aluminate, azo pigments, phthalocyanine pigments, anthraquinone pigments, and the like, but are not limited thereto. The color pigment may be added to the paint composition in an amount known in the art, for example, in the range of about 1-10% by weight based on the total amount of the composition.

In addition to the above-mentioned acrylic modified alkyd resin, solvent, and rust-preventive pigment, the paint composition of the present invention further includes additives commonly used in rust-preventive paint compositions, such as dispersants, thickeners, antifoaming agents, leveling agents, gloss regulators, storage stabilizers, and the like. The physical properties of the composition can be further improved. These additives may be added to the composition in an amount known in the art, such as in the range of about 0.01-10% by weight, in another example about 0.1-5% by weight, based on the total weight of the composition.

Hereinafter, the present invention will be described in detail through examples, but the following examples are merely illustrative of one form of the present invention, and the scope of the present invention is not limited by the following examples.

[ manufacturing example 1-5] - Preparation of alkyd resin

According to the composition shown in Table 1 below, an acid monomer, an alcohol monomer, a catalyst and a solvent were introduced into a reactor and the temperature was gradually raised. Thereafter, when the temperature reached about 130° C. and the condensation water flowed out, the temperature was raised to about 230° C., and the condensation water was removed while maintaining the reaction. After the reaction is complete, it is cooled to about 120° C., diluted with a solvent, and the alkyd resin of Preparation Example 1-5 (solid content: 65% by weight, acid value: 15 or less, weight average molecular weight: 30,000-50,000) is extracted and got it

[ Comparative Manufacturing Example ] - Preparation of alkyd resins

According to the composition shown in Table 1 below, an acid monomer, an alcohol monomer, a catalyst and a solvent were added to a reactor, and the alkyd resin of Comparative Preparation Example (solid content: 65% by weight, acid value: 15 or less, weight average molecular weight in the same manner as in Preparation Example) : 30,000-50,000) was obtained by extraction.

[ Example 1-5] - Preparation of acrylic modified alkyd resin

According to the composition shown in Table 2 below, the alkyd resin, styrene monomer, initiator and solvent were reacted by heating and stirring at a speed of 85 rpm for about 3 hours at a temperature of about 145 ° C. When the reaction is complete, it is cooled, diluted with a solvent (toluene), and the acrylic modified alkyd resin of Example 1-5 (whey: 25-40%, acid value: 15 or less, solid content: 50%, weight average molecular weight: 50,000-100,000 ) was prepared.

[ Comparative Example 1-2] - Preparation of acrylic modified alkyd resin

According to the composition shown in Table 2 below, the acrylic modified alkyd resin of Comparative Example 1-2 (whey: 30-50%, acid value: 15 or less, solid content: 50%, weight average molecular weight: 50,000- 100,000) were prepared.

[ Experimental example ] - Evaluation of physical properties of anti-rust paint composition

According to the compositions shown in Table 3 below, rust-preventive paint compositions of Examples A-E and Comparative Examples A-B were prepared using the acrylic-modified alkyd resin, diluting solvent, and additives of Examples 1-5 and Comparative Examples 1-2, respectively. did

1. Diluting solvent: toluene

2. Additives: Surface stabilizer, plasticizer, desiccant, defoamer (mixing ratio 20:70:7.5:2.5 weight ratio)

Clear Specimen Preparation

After applying the transparent rust-preventive coating compositions prepared in Examples A-E and Comparative Examples A-B to steel sheets, they were dried at room temperature for 48 hours to prepare specimens having transparent coating films (hereinafter referred to as 'transparent specimens').

Black Specimen Preparation

A black anticorrosive coating composition was prepared by mixing a colorant containing a color pigment with the transparent anticorrosive coating compositions prepared in Examples A-E and Comparative Examples A-B at a weight ratio of 100:2. After applying this black anti-rust paint composition to a steel sheet, it was dried at room temperature for 48 hours to prepare a specimen having a black coating film (hereinafter referred to as 'black specimen').

Property evaluation

(1) Non-volatile content (NV, %)

After heating 1 g of the coating composition at a temperature of 150° C. for 15 minutes, the amount of remaining material was measured.

(2) dry thickness

The dry thickness of the coating film formed on the steel plate was measured.

(3) Dryness to the touch

After each coating composition was applied to a glass plate to a thickness of 11-16 μm, the point at which the coating did not come off when touched with a finger while drying at a temperature of 25 ° C. was measured.

(4) fast drying

The test plate was clamped between the thumb and the thumb, and the coating film was pressed with force (do not twist) close to the thumb, and the time point at which fingerprint marks were not formed on the coating film was measured.

(5) Appearance

The appearance of tees, leveling properties, color separation, pinholes, cracks, etc. on the surface of the coating film was visually observed.

(6) Adhesion

After making 100 grids by drawing lines vertically and horizontally at 1 mm intervals using a sharp knife on the dried coating film according to ASTM D3359 TEST METHOD B, attaching cellophane tape and rubbing it, then pulling the tape strongly upwards and then coating Exfoliation was evaluated. At this time, it was evaluated in three stages of good, fine poor, and poor according to the degree of peeling of the coating film.

(7) Impact resistance

After dropping from a height of 25 cm with a weight (diameter: 0.5 inch) having a load of 500 g using a Doupont type impact tester, peeling of the coating film was visually evaluated. At this time, it was evaluated in three stages of good, fine poor, and poor according to the degree of peeling of the coating film.

(8) Anti-rust property

A 5% NaCl salt spray test was performed according to ASTM B117. After spraying for 48 hours, it was confirmed whether there was any lifting or rust on the surface of the coating film. According to the degree of rusting, it was evaluated in three stages: good, fine inferior, and inferior.

The physical properties of each paint composition were evaluated by the above method, and the results are shown in Table 4 below.

As shown in Table 4, the rust-preventive paint composition (Examples A-E) using the acrylic modified alkyd resin according to the present invention exhibits excellent physical properties in all aspects of drying property, appearance characteristics, adhesion, impact resistance, and rust prevention was able to confirm On the other hand, in the case of the rust-preventive paint composition (Comparative Example A) using an acrylic-modified alkyd resin prepared using acid monomers outside the composition of the present invention (equivalent ratio between acid monomers), it was found that touch-drying and stick-drying properties were poor. I was able to confirm. In addition, in the case of the rust-preventive paint composition (Comparative Example B) using an acrylic-modified alkyd resin modified by using less styrene monomer than the scope of the present invention, it was confirmed that the touch-drying property and the fixing-drying property were poor.

Claims (6)

Based on 100 parts by weight of an alkyd resin prepared from a resin composition containing an acid monomer and an alcohol monomer containing fatty acids, acid anhydrides and monovalent or more basic acids in an equivalent ratio of 25-35: 55-60: 5-15, styrene monomer As an acrylic modified alkyd resin prepared using 45-85 parts by weight,
The monovalent or more basic acid is a mixture of an aliphatic base acid and an aromatic base acid in a weight ratio of 1-2: 1,
The alcohol monomer is obtained by mixing C ₁ -C ₁₀ trihydric alcohol and C ₁ -C ₁₀ tetrahydric alcohol at a weight ratio of 1:1.1-1.2,
The weight average molecular weight of the alkyd resin is 30,000-50,000,
An acrylic-modified alkyd resin having a weight average molecular weight of 50,000-100,000 of the acrylic-modified alkyd resin. delete The acrylic modified alkyd resin according to claim 1, wherein the alkyd resin has an acid value of 0-15, solid content of 50-70% by weight, and whey content of 30-60%. The acrylic-modified alkyd resin according to claim 1, wherein the acrylic-modified alkyd resin has an acid value of 0-15, a solid content of 40-60% by weight, and a whey of 25-40%. The acrylic modified alkyd resin according to claim 1, wherein the acid monomer and the alcohol monomer have an equivalent ratio of 1:1 to 1.5. An anticorrosive coating composition comprising the acrylic modified alkyd resin according to any one of claims 1 and 3 to 5.