KR20160113346A - Transparent coating composition for prepairing automobile - Google Patents

Abstract

The present invention relates to a transparent coating composition for repairing automobiles. The transparent coating composition has excellent glossiness, strength, weather resistance, drying properties, and recovery characteristics. Also, the transparent coating composition has excellent dry and wet scratch resistance and, particularly, wet scratch resistance exhibited during an automatic car wash. The transparent coating composition comprises: a main part including acrylic polyol, polyester diol, silica nanoparticles, an additive, a solvent, and a urethane reaction catalyst; and a curing agent part including hexamethylene diisocyanate, xylene, and naphtha.

Description

TRANSPARENT COATING COMPOSITION FOR PREPAIRING AUTOMOBILE [0002]

More particularly, the present invention relates to a clear coating composition for automobile repair, which is excellent in gloss, strength, weatherability and drying property, has a restoration property, and is excellent in both dry and wet scratch resistance, And a clear coating composition for excellent automobile repair.

Automotive repair coatings continue to grow at a faster pace than the overall paint market, as the number of registered automobiles in Korea has steadily increased.

Automotive repair coatings occupy an important position in the paint industry in the sense that they provide a beautiful exterior appearance and the ability to protect the body from the extreme external environment.

Such automotive repair coatings are being developed to realize an environmentally friendly coating process with excellent physical properties.

It is estimated that the automobile OEM Base Coat has been developed by 30% around the world in the automobile paint industry, and the percentage of automobile paint is increasing mainly in Europe. In particular, clearcoat is increasingly using two-pack type urethane due to the increase in consumer's demand for acid resistance and scratch resistance. In addition to increasing the number of base coats, And the development of high-performance clearcoat.

The prior art of such automotive repair coating materials is as follows.

Korean Patent No. 0174809 discloses that 40 to 55% by weight of an epoxy resin containing an oxirane group, 15 to 30% by weight of an organic acid group-containing monomer having a vinyl group, 0.04 to 0.50% by weight of an oxirane ring opening catalyst, and an aromatic non- To 40% by weight of an epoxy acrylate resin composition, and 10 to 30 parts by weight of the epoxy acrylate resin composition and 90 to 70 parts by weight of an unsaturated polyester resin.

Korean Patent Publication No. 2011-0119481 discloses a high solid two-liquid coating composition comprising 70 to 90 parts by weight of a first composition and 10 to 30 parts by weight of a second composition, wherein the first composition is a mixture of 100 parts by weight of the first composition Acrylic polyol having a solid content of 65 to 80% by weight, a weight average molecular weight of 3,000 to 10,000, a number average molecular weight of 700 to 1,500, a glass transition temperature of 50 to 90 ° C and a hydroxyl value of 80 to 150 mg KOH 50 to 80 parts by weight of a resin; 0.01 to 0.1 parts by weight of a curing catalyst; And 20 to 50 parts by weight of a solvent, and the second composition comprises 50 to 80 parts by weight of a polyisocyanate as a curing agent per 100 parts by weight of the second composition; And 20 to 50 parts by weight of a solvent.

The conventional automobile repair coating material has a problem that scratch resistance in dry form is poor and the coating film of a paint having restoration property has a weak strength and a slow drying time. The present inventors repeatedly studied to solve the problems of the conventional paint, The present invention has been completed.

Accordingly, it is an object of the present invention to provide a clear coating composition for automobile repair having excellent gloss, strength, weatherability, dryness, dry and wet scratch resistance, and restoration characteristics satisfying VOC environment regulations.

In order to attain the above object, the present invention provides a process for producing a polyurethane foam, which comprises 50 to 65 parts by weight of an acrylic polyol, 3 to 10 parts by weight of a polyester diol, 0.5 to 2 parts by weight of a silica nanoparticle, 0.1 to 3 parts by weight of an additive, 0.1 to 0.5 parts by weight of a urethane reaction catalyst; And 40 to 60 parts by weight of hexamethylene diisocyanate and 40 to 60 parts by weight of an organic solvent.

In one embodiment of the present invention, silica nanoparticles having an average particle size of 5 to 20 nm can be used as the silica nanoparticles.

In one embodiment of the present invention, the acrylic polyol may be an acrylic polyol having a molecular weight of 2,000 to 10,000, a hydroxyl value of 3 to 4%, and a solid content of 55 to 75%.

In one embodiment of the present invention, the polyester diol preferably has a molecular weight of 500 to 1,500.

In one embodiment of the present invention, a hindered amine light stabilizer, an ultraviolet absorber and a leveling agent may be used as the additive.

In one embodiment of the present invention, the solvent may be selected from the group consisting of xylene, propylene glycol methyl ether acetic acid, dimethyl carbonate, naphtha and methyl isobutyl ketone.

In one embodiment of the present invention, xylene or naphtha may be used as the organic solvent contained in the curing agent.

In an embodiment of the present invention, it is preferable that the main portion and the curing agent portion are mixed at a volume ratio of 2: 1.

The clear coating composition for automobile repair according to the present invention is excellent in gloss, strength, weatherability and dryness, has a self-healing property, that is, a restoration property, and is excellent in both dry and wet scratch resistance, And provides improved appearance characteristics over conventional automotive repair coatings.

In addition, the clear coating composition for repairing automobiles according to the present invention can satisfy the VOC environmental regulation in the discussion with the VOC regulation standard of the Ministry of Environment.

Hereinafter, the clear coating composition for automobile repair according to the present invention will be described in detail.

The transparent coating composition for automobile repair according to the present invention is a two-pack type paint comprising 50 to 65 parts by weight of an acrylic polyol, 3 to 10 parts by weight of a polyester diol, 0.5 to 2 parts by weight of a silica nanoparticle, 0.1 to 3 parts by weight of an additive, 30 to 50 parts by weight of a urethane reaction catalyst and 0.1 to 0.5 parts by weight of a urethane reaction catalyst; 40 to 60 parts by weight of hexamethylene diisocyanate, and 40 to 60 parts by weight of an organic solvent.

The acrylic polyol contained in the main part of the clear coating composition for automobile repair according to the present invention forms a urethane bond with hexamethylene diisocyanate in the curing agent part.

As the acrylic polyol used in the present invention, an acrylic polyol having a molecular weight of 2,000 to 10,000, a hydroxyl value of 3 to 4% and a solid content of 55 to 75% is preferably used.

When the molecular weight of the acrylic polyol is less than 2,000, the coating film formed of the clear coating composition for automobile repair tends to slow down and the viscosity of the coating film tends to decrease. When the molecular weight of the acrylic polyol exceeds 10,000, The leveling property of the coating film may be deteriorated and the gloss may be poor.

When the content of the hydroxyl group of the acrylic polyol is less than 3%, the physical properties of the coating film may be lowered due to the decrease of the crosslinking density when the clear coating composition for automobile repair is used. When the content of the hydroxyl group of the acrylic polyol is more than 4% The compatibility with the curing agent may be deteriorated, and the durability (DOI) of the final coating film may be lowered and the gloss may be lowered.

It is preferable that the acrylic polyol is included in the main part of the clear coating composition for repairing automobiles according to the present invention in an amount of 50 to 65 parts by weight.

When the acrylpolyol is contained in the main part of the clear coating composition for automobile repair according to the present invention in an amount of less than 50 parts by weight, sagging (flow) may occur on the vertical drawing portion due to low viscosity, It may cause a problem that the spraying workability is poor due to the high viscosity .

The main part of the transparent coating composition for automobile repair according to the present invention contains a polyester diol to form a urethane bond with hexamethylene diisocyanate in the curing agent part together with the acrylic polyol.

The polyester diol contained in the main part of the clear coating composition for automobile repair according to the present invention may be urethane-bonded to hexamethylene diisocyanate in the curing agent part, so that the flexibility of the coating film can be increased and the self-healing ability can be improved.

The polyester diol contained in the main part of the clear coating composition for automobile repair according to the present invention preferably has a molecular weight of 500 to 1,500.

When the molecular weight of the polyester diol is less than 500, the scratch resistance of the coating film formed of the transparent coating composition for automobile repair may be deteriorated. When the molecular weight of the polyester diol is more than 1,500, drying is delayed, There is a tendency that the compatibility is deteriorated and the linearity (DOI) of the final formed coating film is lowered.

It is preferable that the transparent coating composition for automobile repair according to the present invention contains 3 to 10 parts by weight of polyester diol in the main part, and the drying may be delayed when the polyester diol is contained in more than 10 parts by weight.

The main part of the clear coating composition for automobile repair according to the present invention contains silica nanoparticles to improve the dry and wet scratch resistance of the final coating film.

The silica nanoparticles are contained in the main portion of the clear coating composition for automobile repair according to the present invention, so that the silica nanoparticles are positioned between the transparent coating compositions of the present invention to enhance the strength of the transparent coating film to improve the scratch resistance of the coating film . This is a principle similar to that when cement is mixed with cement, the strength becomes better.

The silica nanoparticles included in the main part of the clear coating composition for automobile repair according to the present invention preferably use silica nanoparticles having an average particle size of 5 to 20 nm.

The silica nanoparticles used in the present invention may be silica nanoparticles surface-treated with polar silicon or silica nanoparticles surface-treated with non-polar silicon .

In one embodiment of the present invention, as the silica nanoparticles used in the present invention, for example, NANOBYK-3651 manufactured by ALTANA can be used as the silica nanoparticles surface-treated with silicon having a high polarity, As the surface-treated nanoparticles, for example, NONOBYK-3652 manufactured by ALTANA can be used, and nanoparticles surface-treated with non-polar silicon can also be used.

If the average particle size of the silica nanoparticles exceeds 20 nm, there is a possibility that the glossiness and linearity of the final coating film may be lowered (see Test Example 1, below).

The clear coating composition for automobile repair according to the present invention preferably contains silica nanoparticles in an amount of 0.5 to 2 parts by weight. In the clear coating composition for automobile repair according to the present invention, 2 parts by weight of silica nanoparticles (DOI) of the final formed transparent coating film may be lowered and the gloss may be lowered.

As the additives included in the main part of the clear coating composition for automobile repair according to the present invention, a hindered amine light stabilizer, an ultraviolet absorber and a leveling agent are used.

The above-mentioned hindered amine light stabilizer (HALS additive) is used as an additive in the main part of the clear coating composition for automobile repair according to the present invention, and it has an effect of maintaining the glossiness and keeping the characteristics of the coating film when exposed to the external environment.

The ultraviolet absorber is used as an additive in the main part of the clear coating composition for automobile repair according to the present invention, thereby preventing yellowing or blistering when exposed to the outside.

A leveling agent, for example, a silicone additive excellent in leveling property is used as an additive agent in the main part of the clear coating composition for automobile repair according to the present invention, and the spreading property of the coating film is excellent in the spraying operation.

It is preferable that the additive contained in the main part of the transparent coating composition for repairing automobile according to the present invention is included in 0.1 to 3 parts by weight.

Examples of the solvent to be contained in the main part of the clear coating composition for automobile repair according to the present invention include solvents excellent in compatibility with the acrylic polyol, for example, xylene, propylene glycol methyl ether acetic acid, dimethyl carbonate, naphtha and methyl isobutyl ketone , But are not necessarily limited thereto.

It is preferable that the solvent contained in the main part of the clear coating composition for repairing automobile according to the present invention is contained in an amount of 30 to 50 parts by weight.

The urethane reaction catalyst is included in the main part of the clear coating composition for automobile repair according to the present invention to promote the urethane bonding reaction between the acrylic polyol and the polyester diol in the main part and the hexamethylene diisocyanate in the curing agent part.

The urethane reaction catalyst contained in the main part of the transparent coating composition for repairing automobiles according to the present invention is preferably contained in an amount of 0.1 to 0.5 parts by weight.

The curing agent part of the clear coating composition for automobile repair according to the present invention includes hexamethylene diisocyanate excellent in reactivity with acrylic polyol and weathering resistance and organic solvents such as xylene, naphtha and the like.

It is preferable that the above-mentioned main part and curing agent part are mixed in a volume ratio of 2: 1, and the viscosity at the time of mixing is preferably 14 to 18 seconds (25 ° C) in Ford cup # 4.

Hereinafter, preferred embodiments of the present invention will be described in detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

The embodiments described herein are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention, so that various equivalents and modifications may be substituted for them at the time of application of the present invention.

Example

The present invention will be described with reference to the following examples, which do not limit the scope of the present invention.

Example  One

The main components were prepared by mixing the acrylic polyol, polyester diol, silica nanoparticles surface-treated with non-polar silicon, additives, solvent and urethane reaction catalyst in the amounts shown in Table 1 below, using hexamethylene diisocyanate and xylene as curing agents To prepare a clear coating composition for automobile repair according to the present invention.

ingredient Example 1 Acrylic polyol 57 Polyester diol 5 Silica nanoparticles One HALS additive (BASF, Tinuvin 292) 0.4 Ultraviolet absorber (BASF, Tinuvin 1130) 0.6 Leveling agent 2 Propylene glycol methyl ether acetic acid (DOWANOL (TM) 8.9 Dimethyl carbonate 15 Methyl isobutyl ketone 3 xylene One Naphtha (KOCOSOL # 100) 6 Urethane reaction catalyst 0.1 Hardener part Example 1 Hexamethylene diisocyanate 50 xylene 50

(Unit: parts by weight)

Example  2

A clear coating composition for automobile repair was prepared in the same manner as in Example 1, except that silica nanoparticles surface-treated with polar silicon as the silica nanoparticles were used.

Example  3

A clear coating composition for automobile repair was prepared in the same manner as in Example 1, except that silica nanoparticles having an average particle size of 18 nm were used.

Comparative Example  One

A clear coating composition for automobile repair was prepared in the same manner as in Example 1, except that the silica nanoparticles were not used.

Comparative Example  2

A clear coating composition for automobile repair was prepared in the same manner as in Example 1, except that silica nanoparticles having an average particle size of 30 nm were used.

Comparative Example  3

A clear coating composition for automobile repair was prepared in the same manner as in Example 1, except that silica nanoparticles having an average particle size of 50 nm were used.

Test Example  One

The coating film formed by mixing the main part and the hardener part in the ratio of 2: 1 in the clear coating composition for automobile repair manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 was subjected to the physical property test according to the following physical property measuring method, Are shown in Table 2.

How to measure property

(One) Appearance Characteristic Evaluation: Sun spirituality of the film (visual evaluation) `

⊚: very excellent, ◯: excellent in spirituality, △: poor in spirituality, ×: very poor in spirituality

(2) Glossiness measurement: 60 ° using BYK MICRO TRI-GLOSS METER

(3) Acid resistance measurement: Dipping in 20% H2SO4 for 24 hours to confirm the damage of the film

(4) Scratch resistance (dry) measurement: A Crockmeter instrument was used and measured 10 times with a weight of 9N. The polishing paper was subjected to 3M 281Q Wetordry (grade: 9MIC, size: 215.9 * 279.4 mm) After the measurement, the gloss retention rate of the specimen at 20 ° C was measured.

(5) Measurement of scratch resistance (wet): LAB-SCALE CAR WASH APPARATUS AmtecKistler was used and LAB-SCALE CAR WASH APPARATUS was used. The samples were polished with a 1000 mm diameter / 400 mm width polyethylene brush, ) Was 120 rpm, spray nozzle angle was 60 ℃, flow rate was 2.2 L / min (300 kPa), suspension was 1.5 g / L (average particle size 24 ㎛) and water temperature was 15 ~ After the measurement, the gloss retention rate of the specimen at 20 ° C was measured.

(6) Alkalinity measurement: NaOH solution is dropped for 24 hours to check for film damage

(7) Measurement of stability: The dried coating was subjected to a round-trip 50 times with a brush, and the scratch restoration state after 24 hours was visually evaluated

O: No scratch is left by restoration.

△: Restoration is not complete, but some scratches remain.

X: Scratch can not be restored.

ingredient Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Sun spirituality ◎ ◎ ◎ ◎ × × Glossiness 89 86 89 90 85 80 Scratch resistance (dry) 93 85 93 74 92 85 Scratch resistance (wet) 55 59 55 45 52 46 Acid resistance ○ ○ ○ ○ ○ ○ Alkali resistance ○ ○ ○ ○ ○ ○ Stability ○ ○ ○ ○ ○ △

Referring to Table 2, the dry and wet scratch resistance of the coating film formed from the transparent coating composition for automobile repair of Examples 1 to 3, which were prepared by incorporating silica nanoparticles in the main portion, were compared with those prepared without silica nanoparticles Which is superior to the dry and wet scratch resistance of the clear coating composition for automobile repair of Example 1.

It was also found that the coating films formed of the transparent coating compositions for automobile repair of Comparative Examples 2 and 3 using the silica nanoparticles having an average particle size of more than 20 nm had poor gloss and good linearity and poor stability.

Claims (6)

50 to 65 parts by weight of an acrylic polyol, 3 to 10 parts by weight of a polyester diol, 0.5 to 2 parts by weight of a silica nanoparticle, 0.1 to 3 parts by weight of an additive, 30 to 50 parts by weight of a solvent and 0.1 to 0.5 parts by weight of a urethane reaction catalyst Topic section; And
40 to 60 parts by weight of hexamethylene diisocyanate and 40 to 60 parts by weight of an organic solvent containing xylene and naphtha,
Wherein the main portion and the curing agent are mixed in a volume ratio of 2: 1.
The method according to claim 1,
Wherein the silica nanoparticles are silica nanoparticles having an average particle size of 5 to 20 nm.
The method according to claim 1,
Wherein the acrylic polyol is an acrylic polyol having a molecular weight of 2,000 to 10,000, a hydroxyl group content of 3 to 4% and a solid content of 55 to 75%.
The method according to claim 1,
Wherein the polyester diol has a molecular weight of 500 to 1,500.
The method according to claim 1,
Wherein the additive comprises a hindered amine light stabilizer, an ultraviolet absorber and a leveling agent.
The method according to claim 1,
Wherein the solvent is selected from the group consisting of xylene, propylene glycol methyl ether acetic acid, dimethyl carbonate, naphtha and methyl isobutyl ketone.