KR20160078097A - Paint composition and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a paint composition and a production method thereof. According to the present invention, the paint composition exhibits excellent chipping resistance due to elastic force applied to a urethane-modified polyester resin based on curable paint films. In addition, the paint composition also has superior material properties including exteriors, impact resistance, and adhesive properties as well.

Description

[0001] Paint composition and manufacturing method thereof [0002]

The present invention relates to a coating composition and a method for producing the same.

In general, steel has excellent rigidity according to its inherent characteristics, but has a problem of rusting when exposed to water. In addition, plastics are vulnerable to chemicals, erosion, ultraviolet rays, discoloration and the like, and have surface defects due to flow, flaws, color limitation, In order to solve these problems, the paints have been painted in the past to compensate for defects of steel or plastic materials, and at the same time, colors have been imparted to improve appearance.

However, as the society develops, the demand level of the products of consumers is increasing. In recent years, for the materials which are frequently encountered in the living environment, soft and luxurious texture is given to the surface characteristics of the material as well as physical properties and appearance, .

For example, as a coating composition, a polyester, an epoxy, a polyester-modified epoxy, an epoxy-modified polyester, an acrylic resin and the like are mainly used.

Among them, a coating composition comprising a polyester resin is widely used because of its excellent processability. However, the polyester resin has excellent processability, but is poor in alkali resistance and corrosion resistance. The polyester resin is formed by reacting at a high reaction temperature for a long time and contains moisture in the reaction product. Therefore, there is also a problem that the polyester resin is discolored or deteriorated in properties due to oxidation, deterioration, undesired side reactions, and the like.

Therefore, development of a coating material excellent in coating film characteristics such as resistance to chipping, impact resistance, adhesion, chemical resistance, abrasion resistance, alcohol resistance and / or scratch resistance has been demanded.

Korea Patent No. 2012-0110268

The present invention relates to a coating composition and a method for producing the same, and is intended to provide a coating composition which is excellent in physical properties such as appearance, chipping resistance, impact resistance and adhesion while preventing deterioration of processability.

The present invention relates to a coating composition and a method for producing the same.

As one example of the coating composition,

30 to 45 parts by weight of a urethane-modified polyester resin;

15 to 25 parts by weight of a curing agent; And

25 to 35 parts by weight of a pigment,

The above-mentioned urethane-modified polyester resin preferably contains, based on 100% by weight of the urethane-modified polyester resin,

It is possible to provide a coating composition containing at least 40% by weight of a urethane-modified polyester resin having dimeric acid and butadiene rubber-modified hydroxy groups.

As an example of the method for preparing the coating composition,

Chain extension by mixing a butadiene rubber with a polyester resin modified with a dimer acid; And

And a step of mixing the chain-extended modified polyester resin and the aliphatic diisocyanate to prepare a urethane-modified polyester resin.

The coating composition according to the present invention is superior in chipping resistance due to the elastic force added to the urethane-modified polyester resin on the basis of the cured coating film, and has excellent physical properties such as appearance, impact resistance and adhesion.

Fig. 1 is a photograph showing the evaluation results of the chipping resistance of the cured coating film of the coating composition according to the present invention in one embodiment. Fig.
2 is a photograph showing the evaluation results of the chipping resistance of a cured coating film of a coating composition according to a comparative example.

In the present invention, the weight refers to a content ratio between individual components, for example, a weight-based mixing ratio between components.

As one example, the coating composition according to the present invention may contain,

30 to 45 parts by weight of a urethane-modified polyester resin;

15 to 25 parts by weight of a curing agent; And

25 to 35 parts by weight of a pigment,

The above-mentioned urethane-modified polyester resin preferably contains, based on 100% by weight of the urethane-modified polyester resin,

It is possible to provide a coating composition containing at least 40% by weight of a urethane-modified polyester resin having dimeric acid and butadiene rubber-modified hydroxy groups.

The urethane-modified polyester resin having a hydroxy group in which the dimeric acid and butadiene rubber are modified may contain 40 to 100% by weight or 50 to 100% by weight, based on 100 parts by weight of the urethane-modified polyester resin . By controlling the content of the raw materials within the above range, a coating composition excellent in chipping resistance and adhesion can be produced.

At this time, the ratio of the content of the urethane-modified polyester resin to the content of the curing agent may satisfy the following general formula (1).

[Formula 1]

P / H ≤ 3

In the general formula 1,

P represents the content (parts by weight) of the urethane-modified polyester resin,

H represents the content (parts by weight) of the curing agent.

Specifically, the content of the urethane-modified polyester resin with respect to the content of the curing agent can be controlled to 3 or less. For example, the content ratio can be controlled to 1 to 3 or 1.5 to 2. By controlling the content ratio within the above range, the chipping resistance of the coating composition can be further improved.

The urethane-modified polyester resin having a hydroxy group in which the dimeric acid and butadiene rubber are modified includes a chain extended structure by introducing a butadiene rubber into a polyester resin modified with a dimeric acid. Further, urethane denaturation is added to the chain extended polyester resin using a diisocyanate to form a urethane-modified polyester resin having a hydroxy group.

Specifically, the dimer acid may have a part of unsaturated bonds as a fatty acid, but it is preferable to use hydrogenated dimer acid due to the characteristics of automotive coating materials. Also, in the case of the butadiene rubber used together with dimer acid, the content of acrylonitrile becomes an important factor. The average molecular weight of the dimeric acid and butadiene rubber is preferably in the range of 200 to 1,000 g / mol or 1,000 to 5,000 g / mol, respectively.

The coating composition may form a cured coating film through a curing step. At this time, the curing step is usually carried out for curing, and there is no particular limitation.

The cured coating film, which is obtained by curing the coating composition,

When allowed to stand at -20 ° C for 2 hours, and evaluated for chipping resistance through the MS 653-01 evaluation grade,

The chipping resistance of the cured product may be at least grade 2.

Specifically, in the measurement of the chipping resistance, the specimen was prepared by using the prepared coating film, and the specimen was left in a chipping room at -20 ° C for 2 hours. Then, the specimen was inclined at 45 °, The pressure was set to be Stone / Gravel Chip.

As a result, it can be seen that the modified polyester resin according to the present invention can realize excellent chipping resistance, thereby effectively protecting the coating film from chipping.

The dimer acid may be a hydrogenated dimer acid. Specifically, it may be a hydrogenated dimer acid. By using hydrogenated dimer acid to hydrogenate dimer acid, it is possible to prevent degradation of the weather resistance of the polyester resin. For example, the dimer acid may comprise at least one of a dimer fatty acid and a hydrogenated dimer fatty acid.

The butadiene rubber may be a butadiene rubber blocked with at least one of a carboxyl group, a hydroxyl group and an amino group. By incorporating the butadiene rubber into the polyester resin, the chains of the polyester resin can be elongated, and elasticity can be imparted to improve the chipping resistance. For example, the butadiene rubber may include a carboxyl terminated butadiene acrylonitrile copolymer and / or a butadiene homopolymer.

The curing agent may include at least one of isocyanate and melamine resin. For example, the isocyanate may be a block isocyanate. Also, the melamine resin may be a methoxy melamine resin having a molecular weight of 300 to 1,000, a butoxy melamine resin, or a mixed methoxy / butoxy / methoxy resin. In some cases, the curing agent may be used in combination with a block isocyanate and a melamine resin. The use of the isocyanate and melamine resin as a curing agent can prevent lowering of the compatibility with the polyester resin and prevent the problem that the melamine is transferred to the upper layer of the coating film after the formation of the coating film,

The pigment may be used singly or in combination of two or more kinds of pigments. Examples of the pigment include TiO ₂ white pigment, carbon black based FW285, Raven Ultra 5000, Raven 3500, Blanc Fixe Micro, Hostaperm Violet RL-S, Heliogen Green L8730, Manstral Blue FNX, Sicopal Yellow L1100, Paliotan Yellow L1945, Irgazin DPP BO, and Hostaperm Red E3B. In addition, organic and inorganic pigments that can be used in paints can be used.

The content of the pigment may be 25 to 35 parts by weight, or 27 to 32 parts by weight, based on 100 parts by weight of the whole coating composition. When two kinds of pigments are used in combination, it is possible to mix the first and second pigments in a ratio of 0.5 to 1.1: 1. By controlling the content of the pigment in the above-described range, it is possible to prevent defective undercoating hiding power, prevent leveling of the paint and prevent deterioration of clearness, and further prevent deterioration of impact resistance and chipping resistance due to the brittle coating film characteristic.

The coating composition may further comprise a solvent or other additives. For example, 10 to 30 parts by weight of a solvent and 0.1 to 5 parts by weight of other additives may be contained based on 100 parts by weight of the entire coating composition.

The type of the solvent is not particularly limited and can be selected at a level that is excellent in dissolving power and stability and does not interfere with the main reaction.

The other additives may include various substances such as a surfactant, an adhesion promoter, a leveling agent, a defoaming agent, a curing accelerator and a dispersing agent in consideration of the properties required for the coating composition. For example, an acrylic or polyester dispersant may be used as the dispersing agent. As the leveling agent, a polyether-modified dimethylpolysiloxane, a 2,4,7,9-tetramethyl-5-decene-4,7-diol and / or a modified urea mixture can be used.

The present invention can also provide a method for producing the above-described coating composition.

As one example of the method for producing the coating composition,

Chain extension by mixing a butadiene rubber with a polyester resin modified with a dimer acid; And

And a step of mixing the chain-extended modified polyester resin and the aliphatic diisocyanate to prepare a urethane-modified polyester resin.

Specifically, the method for producing the coating composition comprises: 30 to 45 parts by weight of a urethane-modified polyester resin; 15 to 25 parts by weight of a curing agent; And 25 to 35 parts by weight of the pigment. However, at this time, the urethane-modified polyester resin may contain, based on 100% by weight of the urethane-modified polyester resin,

Chain extension by mixing a butadiene rubber with a polyester resin modified with a dimer acid; And

The urethane-modified polyester resin prepared by mixing the chain-extended modified polyester resin and the aliphatic diisocyanate to prepare the urethane-modified polyester resin may contain not less than 40% by weight of the urethane-modified polyester resin.

The dimer acid, the butadiene rubber, the curing agent and the pigment may be the same as those described above.

The polyester resin modified with the dimeric acid can be produced under a nitrogen atmosphere. For example, the process can be carried out in a reactor equipped with a stirrer, a thermometer, a nitrogen injection tube, a filling column, a separation tube (for example, H type separation tube) and a cooler. At this time, a dimer acid-modified polyester resin can be prepared by mixing a dimer acid and a precursor for forming a polyester resin in a reactor, injecting nitrogen through a nitrogen injection tube, and forming a reactor atmosphere in a nitrogen atmosphere.

For example, in the step of chain extension by mixing the polyester resin modified with the dimeric acid and the butadiene rubber, the content ratio of the dimeric acid and the butadiene rubber used is 5 to 40: 1 to 20 (parts by weight), or 7 ~ 20: 3 ~ 10.

Specifically, in the step of producing a polyester resin modified with dimeric acid, the content of dimeric acid is 40 parts by weight or less, 5 to 40 parts by weight, or 7 to 20 parts by weight, based on 100 parts by weight of the entire modified polyester resin Can be negative. By controlling the content of the dimer acid within the above range, it is possible to enhance the weather resistance and adhesion of the resin, and to prevent deterioration in storage stability and reactivity.

It is possible to extend the chain by mixing the modified polyester resin with the butadiene rubber. As one example, the content of the butadiene rubber may be 20 parts by weight or less, 1 to 20 parts by weight, 5 to 18 parts by weight, or 4 to 10 parts by weight, based on 100 parts by weight of the entire modified polyester resin. By controlling the content of the butadiene rubber within the above range, the chipping resistance and the impact resistance of the resin can be improved.

The step of chain extension by mixing the dimeric acid-modified polyester resin with the butadiene rubber may be carried out by maintaining the acid value of the mixed solution to 1 mg KOH / g or less, or 0.001 to 1 mg KOH . By controlling the acid value of the mixed solution to the above-mentioned range, the degree of reaction of the modified polyester resin can be appropriately controlled and the problem of mechanical property deterioration caused by unreacted materials can be prevented.

Then, the aliphatic diisocyanate can be used to induce urethane modification, whereby a urethane-modified polyester resin having a hydroxy group in which dimeric acid and butadiene rubber are modified can be produced.

Hereinafter, the present invention will be described in more detail by way of examples and the like. The embodiments of the present invention are intended to be illustrative of the invention and are not intended to limit the scope of the invention.

Manufacturing example : Dimer Mountains  Butadiene rubber is modified Hydroxy group  (A urethane-modified polyester resin (A)) having a urethane-modified polyester resin

30 g of butane diglycol, 25 g of trimethylolpropane, 35 g of hexane diglycol, 24 g of dimer acid and 100 g of isophthalic acid were put into a four-necked flask for synthesis, equipped with a thermometer and a stirrer. At this time, nitrogen gas was injected into the flask and the temperature was gradually raised to 210 deg. After the temperature was elevated, 10 g of butadiene rubber was added and maintained until the acid value became 1 mg KOH / g or less. The reaction was then cooled to 100 DEG C and 15 grams of hexamethylene diisocyanate was added and held for a further 4 hours. Then, the mixture was diluted with a solvent of xylene and propylene glycol methyl ether acetate so that a dimer acid having a solid content of 60% and a hydroxy group having a denatured butadiene rubber To obtain a urethane-modified polyester resin (urethane-modified polyester resin (A)).

Example  1 to 2 and Comparative Example  1 to 2

The coating compositions were prepared according to the following Table 1 by controlling the constituents and the contents. First, a pigment 1, a pigment 2, a solvent, a dispersant and a melamine resin were added to carry out a dispersion process. Then, each polyester resin, a block isocyanate, a leveling agent and a defoaming agent were added to prepare a white paint composition.

The specific constituents and contents are shown in Table 1 below.

Constituent Example 1
(Parts by weight) Example 2
(Parts by weight) Comparative Example 1
(Parts by weight) Comparative Example 2
(Parts by weight) The urethane-modified polyester resin (A) 34 17 0 7 The urethane-modified polyester resin (B) 0 17 34 27 Melamine resin 18 18 18 18 Block isocyanate 2 2 2 2 Leveling agent 0.5 0.5 0.5 0.5 Defoamer 0.1 0.1 0.1 0.1 Dispersant 0.05 0.05 0.05 0.05 Butyl acetate One One One One menstruum 13.5 13.5 13.5 13.5 Butanol 0.85 0.85 0.85 0.85 Pigment 1 15 15 15 15 Pigment 2 15 15 15 15

* Urethane Modified Polyester Resin (A): A resin produced according to Production Example

* Urethane Modified Polyester Resin (B): Urethane modified polyester resin with addition of diisocyanate (manufactured by KCC)

Solvent: Cocosol 100 (Kocosol-100)

* Pigment 1: TiO ₂ , Dupont

* Pigment 2: BaSO ₄ , Sachtleben

* Leveling agents: BYK-315, BYK

* Antifoaming agent: BYK-051, BYK

Experimental Example

The coating compositions prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were painted using an electrostatic bell automatic coater to prepare a white cured coating film. At this time, the discharge amount was controlled at 170 to 250 cc / min. After the coating, the appearance, adhesion, hardness and chipping resistance were measured after curing at 140 ° C for 20 minutes. The measurement conditions are described below.

(1) Appearance (gloss, smoothness) measurement experiment

The gloss of the cured coating film was measured by a polisher (BYK Micro gloss), and the smoothness of the coating film was measured by Wave scan Dual to determine the long wave value.

(2) Adhesion measurement experiment

The cured coating film thus formed was cross-cut (width x length = 2 x 2 mm, 100 lattice) to check whether or not the coated film was adhered. At this time, according to the degree of adhesion, it was indicated as good, medium and poor.

Good: Maintains adhesion without falling coating

Medium: 1-2 drops

Poor: more than 3 drops

(3) Hardness measurement experiment

The prepared cured coating film was measured by a pencil hardness method. Specifically, the hardness of each of the 3B, 2B, B, HB, F, H, 2H, and 3H pencils was measured so as not to damage the coating film.

(4) Measurement of chipping resistance

The prepared cured coating film was left in a chipping room at -20 ° C for 2 hours, and then the coated film was placed at an inclination of 45 ° and mounted at a pressure of 5 bar so as to be a Stone / Gravel chip. At this time, the chipping resistance was evaluated through MS 653-01 evaluation grade.

The physical properties of the cured coating film thus measured are shown in Table 2 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Polish 90 89 89 88 Smoothness (LW) 6 6 7 7 Attachment Good Good Good Good Hardness HB HB HB HB Chipping resistance 2nd grade 2nd grade Class 3 Class 3

Referring to the above Table 2, the cured coating films of the coating compositions according to Examples 1 and 2 are superior in chipping resistance to those of Comparative Examples 1 and 2, and have physical properties such as gloss, smoothness, In the same period.

In addition, as in Comparative Examples 1 and 2, when dimer acid and butadiene rubber were modified with a hydroxy group It was confirmed that when the content of the urethane-modified polyester resin (urethane-modified polyester resin (A)) was too large or small, the hardness and the chipping resistance were lowered as compared with Examples 1 and 2.

1 and 2, the evaluation of the chipping resistance of the cured coating film of the coating composition according to Example 1 and Comparative Example 1 can be confirmed. Specifically, FIG. 1 shows that the evaluation of the chipping resistance of the white cured coating film according to Example 1 was evaluated as grade 2.

On the other hand, FIG. 2 shows that the evaluation of the chipping resistance of the white cured coating film according to Comparative Example 1 shows that the cured coating film according to Comparative Example 1 is evaluated as grade 3, It was confirmed that the chipping resistance was lowered.

Claims (6)

30 to 45 parts by weight of a urethane-modified polyester resin;
15 to 25 parts by weight of a curing agent; And
25 to 35 parts by weight of a pigment,
The above-mentioned urethane-modified polyester resin preferably contains, based on 100% by weight of the urethane-modified polyester resin,
A coating composition comprising 40 wt% or more of a urethane-modified polyester resin having dimeric acid and butadiene rubber-modified hydroxy groups.
The method according to claim 1,
The cured coating film of the coating composition,
Characterized in that when the chipping resistance is evaluated through the MS 653-01 evaluation grade after being left at -20 占 폚 for 2 hours, the hardness of the cured product is not less than grade 2.
The method according to claim 1,
The dimer acid is a hydrogenated dimer acid,
The butadiene rubber is a butadiene rubber blocked with at least one of a carboxyl group, a hydroxyl group and an amino group,
Wherein the curing agent comprises at least one of a block isocyanate and a melamine resin.
Chain extension by mixing a butadiene rubber with a polyester resin modified with a dimer acid; And
And a step of mixing the chain-extended modified polyester resin and the aliphatic diisocyanate to prepare a urethane-modified polyester resin.
5. The method of claim 4,
30 to 45 parts by weight of a urethane-modified polyester resin; 15 to 25 parts by weight of a curing agent; And 25 to 35 parts by weight of a pigment,
The above-mentioned urethane-modified polyester resin preferably contains, based on 100% by weight of the urethane-modified polyester resin,
A process for producing a coating composition comprising the urethane-modified polyester resin produced by the method of claim 4 in an amount of 40% by weight or more.
5. The method of claim 4,
The step of chain extending by mixing a dimeric acid-modified polyester resin with a butadiene rubber,
And maintaining the acid value to 1 mg KOH / g or less.

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