KR102406720B1 - Primer composition - Google Patents

Abstract

The present invention relates to a primer composition comprising a chlorinated polyolefin-based resin, an epoxy resin, a pigment and a solvent, the solvent includes an exempt solvent, and the exempt solvent includes a ketone-based solvent.

Description

Primer composition {PRIMER COMPOSITION}

The present invention relates to a primer composition having a low content of volatile organic compounds (VOC), which is environmentally friendly, and excellent in hiding power and storage stability.

Among important catch phrases applied to each industry recently, eco-friendliness is materialized in the form of actively restricting the use of volatile organic compounds (VOCs). In addition, as part of the restrictions, sanctions for products containing volatile organic compounds are being added.

The volatile organic compound has a property of volatilizing easily at room temperature, and when it exists in a gaseous state, it is naturally emitted in the air environment and is an important cause of air pollution. These volatile organic compounds are known to cause various types of environmental problems by inherent biotoxicity and chemical reactivity. Specifically, volatile organic compounds are known to be the main culprits of serious environmental destruction such as the generation of ozone layer in the troposphere and the cause of stratospheric destruction, inducing the greenhouse effect, and generating odors.

On the other hand, it is common for automobile plastic parts to be painted and used in order to improve the appearance characteristics and protect the surface from the external environment. At this time, the painting treatment is usually a pretreatment to improve the surface tension between the plastic part and the paint through flame or corona discharge treatment, a primer treatment to increase the adhesion between the plastic part and the base coating film, and to improve the appearance characteristics and protect the appearance of the plastic part It consists of a base coating film for In this case, a polyolefin-based resin is usually used as a primer, and a polyurethane dispersion, a polyurethane polyol, an acrylic emulsion, etc. are generally used as a base paint.

In this regard, Korean Patent Registration No. 1,407,133 (Patent Document 1) discloses (a) water-soluble chlorinated polyolefin dispersion, (b) polyurethane dispersion, (c) micronized silica, (d) epoxy resin, (e ) Disclosed is a water-soluble primer composition comprising ion-exchanged water, and (f) amines that are basic curing catalysts. However, the water-soluble primer composition of Patent Document 1 has limitations in terms of dryness and adhesion.

Therefore, there is a need for research and development on a primer composition that is eco-friendly due to a low content of volatile organic compounds, has excellent adhesion between the substrate and top coat, and has excellent storage stability and hiding power.

Korean Patent Registration No. 1,407,133 (published on: 2009.4.27.)

Accordingly, the present invention provides a primer composition that is environmentally friendly due to a low content of volatile organic compounds, has excellent adhesion between a substrate and a top coat, and has excellent storage stability and hiding power.

The present invention includes a chlorinated polyolefin-based resin, an epoxy resin, a pigment and a solvent,

The solvent comprises an exempt solvent,

The exempt solvent is a primer composition comprising a ketone-based solvent.

The primer composition according to the present invention is eco-friendly due to a low content of volatile organic compounds, excellent adhesion between the substrate and top coat, and excellent storage stability and hiding power, so it is suitable as a primer for automobile parts.

Hereinafter, the present invention will be described in detail.

As used herein, "weight average molecular weight" is measured by a conventional method known in the art, for example, it can be measured by a GPC (gel permeation chromatograph) method. In addition, the "glass transition temperature" is measured by a conventional method known in the art, for example, it can be measured by differential scanning calorimetry (DSC).

The primer composition according to the present invention includes a chlorinated polyolefin-based resin, an epoxy resin, a pigment, and a solvent.

Chlorinated polyolefin resin

The chlorinated polyolefin-based resin improves adhesion to the substrate and serves to contribute to the physical properties of the prepared coating film.

The chlorinated polyolefin-based resin means a polyolefin resin modified with chlorine (Cl), and the polyolefin resin includes at least one selected from the group consisting of polyethylene, polypropylene, polyisopropylene, polybutylene, and copolymers thereof. can do.

Specifically, the chlorinated polyolefin-based resin may be a chlorinated polyolefin resin modified with an acid. When an acid-modified chlorinated polyolefin-based resin is used as the chlorinated polyolefin-based resin, an excellent appearance is obtained.

In addition, the acid that can be used when the chlorinated polyolefin resin is modified may be carboxylic acid or anhydride acid. For example, the acid includes carboxylic acids such as (meth)acrylic acid, maleic acid, and fumaric acid; or itaconic anhydride, glutaric anhydride, citraconic anhydride, phthalic anhydride, methylnadic anhydride, succinic anhydride, maleic anhydride, pyromellitic anhydride, 1,2-dicyclohexanedicarboxylic acid, etc. It may include one or more selected from the group consisting of oxalic acid.

In addition, the chlorinated polyolefin-based resin may have a weight average molecular weight (Mw) of 50,000 to 80,000 g/mol, or 55,000 to 70,000 g/mol. When the weight average molecular weight of the chlorinated polyolefin-based resin is within the above range, there is an effect of excellent heat resistance to the material.

The chlorinated polyolefin-based resin may have a chlorine content of 20 to 30% by weight, or 22 to 27% by weight, based on the total weight of the resin. When the chlorine content of the chlorinated polyolefin-based resin is within the above range, there is an excellent effect in water resistance and chemical resistance.

The chlorinated polyolefin-based resin may have an acid content of 0.5 to 2.5 wt%, or 1 to 2 wt%, based on the total weight of the resin. When the acid content of the chlorinated polyolefin-based resin is within the above range, there is an effect of excellent chemical resistance.

In addition, the chlorinated polyolefin-based resin may have a viscosity of 5 to 100 mPa·s, or 10 to 50 mPa·s at 25°C. When the viscosity of the chlorinated polyolefin-based resin is within the above range, there is an effect excellent in appearance and storage properties of the resin itself.

The chlorinated polyolefin-based resin may be included in the composition in an amount of 1 to 10 parts by weight, or 4 to 9 parts by weight based on 0.1 to 5 parts by weight of the epoxy resin. When the content of the chlorinated polyolefin-based resin is within the above range, problems of deterioration in water resistance, adhesion properties of the coating film and appearance may be prevented.

epoxy resin

The epoxy resin serves to improve adhesion with the top coat.

The epoxy resin is not particularly limited as long as it is commonly used in paints or primer compositions, and for example, a bisphenol type epoxy resin, an alicyclic epoxy resin, an aliphatic chain epoxy resin, a phenol novolak type epoxy resin, a cresol novolak type Epoxy resin, diglycidyl ether of biphenol, diglycidyl ether of naphthalenediol, diglycidyl ether of phenol, diglycidyl ether of alcohol, polyfunctional epoxy resin, heterocyclic containing An epoxy resin etc. are mentioned. Specifically, the epoxy resin may be at least one selected from the group consisting of a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, and a bisphenol S-type epoxy resin.

In addition, the epoxy resin may have an epoxy equivalent weight (EEW) of 100 to 300 g/eq, or 160 to 200 g/eq. When the epoxy equivalent of the epoxy resin is within the above range, there is an effect of excellent storability.

The epoxy resin may have a viscosity at 25°C of 8,000 to 20,000 cps, or 10,000 to 15,000 cps. When the viscosity of the epoxy resin is within the above range, there is an effect of excellent storability.

The epoxy resin may have a specific gravity of 0.8 to 1.5, or 1.0 to 1.3 at 20°C. When the specific gravity at 20° C. of the epoxy resin is within the above range, there is an effect of excellent storage properties.

The epoxy resin may have a weight average molecular weight (Mw) of 500 to 1,500 g/mol, or 750 to 1,300 g/mol. When the weight average molecular weight of the epoxy resin is within the above range, there is an effect of excellent storability.

The epoxy resin may have a glass transition temperature (Tg) of 7 to 30 °C, or 10 to 20 °C. When the glass transition temperature of the epoxy resin is within the above range, there is an effect of excellent water resistance.

The epoxy resin may be included in the composition in an amount of 0.1 to 5 parts by weight, or 0.1 to 2 parts by weight based on 1 to 10 parts by weight of the chlorinated polyolefin-based resin. When the content of the epoxy resin is within the above range, there is an effect of improving adhesion with the top coat.

pigment

The pigment serves to impart color to the coating film prepared from the composition. In this case, the pigment may be, for example, a color pigment, an extender pigment, or a mixture thereof.

The colored pigment serves to secure hiding power and impart color to the coating film. In this case, the color pigment may be a black pigment, a white pigment, a blue pigment, a red pigment, a yellow pigment, a violet pigment, or a mixture thereof. In this case, the black pigment may be used without any particular limitation as long as it is a commonly known black pigment, for example, carbon black, graphite, iron oxide, or a mixture thereof may be used. In addition, the white pigment may be used without any particular limitation as long as it is a commonly known white pigment, for example, titanium dioxide (TiO ₂ ) and the like may be used.

The extender pigment serves to increase the strength of the prepared coating film. The extender pigment may be used without particular limitation as long as it is a commonly known component, for example, talc, calcium carbonate, barium sulfate, calcium silicate, or a mixture thereof may be used.

The pigment may be included in the composition in an amount of 1 to 10 parts by weight, or 2 to 6 parts by weight based on 1 to 10 parts by weight of the chlorinated polyolefin-based resin. When the content of the pigment is within the above range, it is possible to prevent problems in which the hiding power of the prepared coating film is lowered or the adhesion force of the coating film is lowered.

solvent

The solvent controls the viscosity of the primer composition to improve workability, control the drying rate, and control the content of volatile organic compounds (VOC). In particular, the solvent has an effect of increasing the eco-friendliness by lowering the content of the volatile organic compound in the composition, including the exempt solvent.

The solvent includes an exempt solvent, and the exempt solvent includes a ketone-based solvent. For example, the ketone-based exempt solvent may be acetone, dimethyl carbonate, tert-butyl acetate, or a mixture thereof.

In addition, the solvent may include an additional solvent such as an aromatic hydrocarbon-based solvent or an ether-based solvent. The aromatic hydrocarbon-based solvent may be, for example, xylene, toluene, or a mixture thereof. Moreover, as a commercial item of the said aromatic hydrocarbon type solvent, Cocosol #100, Cocosol #150, etc. are mentioned. In addition, the ether-based solvent is, for example, di-n-butyl ether, di-isobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, Di-tert-amyl ether, di-n-hexyl ether, methyl cyclopentyl ether, methyl cyclohexyl ether, methyl phenyl ether, methyl benzyl ether, ethyl cyclopentyl ether, ethyl cyclohexyl ether, ethyl phenyl ether, ethyl benzyl ether or these may be a mixture of

The solvent may be included in the composition in an amount of 80 to 95 parts by weight, or 85 to 90 parts by weight based on 1 to 10 parts by weight of the chlorinated polyolefin-based resin. For example, the solvent may include 50 to 85 parts by weight or 60 to 75 parts by weight of an additional solvent based on 1 to 10 parts by weight of the chlorinated polyolefin-based resin, and 10 to 28 parts by weight or 15 to 25 parts by weight of an exempt solvent. have.

When the solvent content in the primer composition is within the above range, the storage stability of the composition is improved. When the content of the exempt solvent is within the above range, the content of the volatile organic compound in the composition is low, and thus, there is an excellent effect of eco-friendliness.

storage enhancer

The primer composition may further include a shelf life improving agent. In this case, the storability improver serves to control the viscosity of the primer composition to control fluidity and to improve the storability of the composition.

The storage improvement agent is not particularly limited as long as it can be conventionally used in the coating composition. For example, fumed silica, organo clay, silica, wax, urea, or a mixture thereof may be used as the storage property improving agent.

The storage property improving agent may be included in the composition in an amount of 0.1 to 5 parts by weight, or 0.5 to 1.5 parts by weight based on 1 to 10 parts by weight of the chlorinated polyolefin-based resin. When the content of the storability improving agent is within the above range, the problem of difficult to control the viscosity of the primer composition and the problem of poor storability of the composition can be prevented.

The primer composition has a podcup viscosity of 5 to 20 seconds, or 9 to 14 seconds at 25° C. based on Podcup No. 4, and a solids content of 5 to 20% by weight, or 9 to 13% by weight, based on the total weight of the composition. may include

In addition, the primer composition may have a volatile organic compound content of 700 g/L or less, or 680 g/L or less. In addition, the primer composition may have a specific gravity of 1.03 or less, 1.00 or less, or 0.98 or less.

As described above, the primer composition according to the present invention has a low content of volatile organic compounds, is eco-friendly, has excellent adhesion between the substrate and top coat, and has excellent storage stability and hiding power, so it is suitable as a primer for automobile parts.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Examples 1 to 10 and Comparative Examples 1 to 3. Preparation of aqueous coating composition

A primer composition was prepared by mixing each component in the composition as shown in Tables 1 and 2 below.

Ingredients (parts by weight) Example One 2 3 4 5 6 7 8 9 10 first epoxy resin 0.4 - - 0.4 0.4 One 1.5 2 0.4 0.4 2nd epoxy resin - 0.4 - - - - - - - - 3rd Epoxy Resin - - 0.4 - - - - - - - 1st chlorinated polyolefin resin 6.8 6.8 6.8 - - 8 6.5 5.5 - - Second chlorinated polyolefin resin - - - 6.8 - - - - - - Third chlorinated polyolefin resin - - - - 6.8 - - - - - 4th chlorinated polyolefin resin - - - - - - - - 6.8 - 5th chlorinated polyolefin resin - - - - - - - - - 6.8 titanium dioxide 4 4 4 4 4 3 3.5 3.5 4 4 carbon black 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 silica 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 toluene 63 63 63 63 63 62 62 62 63 63 xylene 5.8 5.8 5.8 5.8 5.8 6 6.5 6 5.8 5.8 dimethyl carbonate 19.2 19.2 19.2 19.2 19.2 19.2 19.2 20.2 19.2 19.2 total amount 100 100 100 100 100 100 100 100 100 100

Ingredients (parts by weight) comparative example One 2 3 first epoxy resin - 7.2 0.4 1st chlorinated polyolefin resin 7.2 - 6.8 titanium dioxide 4 4 4 carbon black 0.1 0.1 0.1 silica 0.7 0.7 0.7 toluene 63 63 63 xylene 5.8 5.8 25 dimethyl carbonate 19.2 19.2 - total amount 100 100 100

Hereinafter, manufacturers and product names of each component used in Examples and Comparative Examples are shown in Table 3 below.

ingredient note first epoxy resin EEW: 180 g/eq, viscosity at 25°C: 12,000 cps, specific gravity at 20°C: 1.0, Mw: 760 g/mol 2nd epoxy resin EEW: 160 g/eq, viscosity at 25°C: 10,000 cps, specific gravity at 20°C: 1.0, Mw: 910 g/mol 3rd Epoxy Resin EEW: 200 g/eq, viscosity at 25°C: 15,000 cps, specific gravity at 20°C: 1.1, Mw: 1,280 g/mol 1st chlorinated polyolefin resin Maleic anhydride-modified chlorinated polypropylene (chlorine content: 25.5% by weight, viscosity at 25°C: 20mPa·s, Mw: 60,000 g/mol, acid content: 1.5% by weight) Second chlorinated polyolefin resin Maleic anhydride-modified chlorinated polypropylene (chlorine content: 22.5% by weight, viscosity at 25°C: 15mPa·s, Mw: 56,000g/mol, acid content: 1.1% by weight) Third chlorinated polyolefin resin Maleic anhydride-modified chlorinated polypropylene (chlorine content: 26.5 wt%, viscosity at 25°C: 40 mPa·s, Mw: 68,000 g/mol, acid content: 1.7 wt%) 4th chlorinated polyolefin resin Maleic acid-modified chlorinated polypropylene (chlorine content: 23% by weight, viscosity at 25°C: 18mPa·s, Mw: 55,300/mol, acid content: 1.2% by weight) 5th chlorinated polyolefin resin Maleic acid-modified chlorinated polypropylene (chlorine content: 26.8 wt%, viscosity at 25°C: 31 mPa s, Mw: 69,100 g/mol, acid content: 1.85 wt%) silica Synthetic Fumed Silica (Product Name: AEROSIL R-972)

Test Example: Evaluation of the properties of the prepared coating film

The primer compositions of Examples and Comparative Examples were coated on a material made of a nylon material to a dry film thickness of 12 μm, and left at room temperature for 3 minutes. After drying by blowing hot air at 60°C for 5 minutes, apply an oil-soluble clear paint (manufacturer: KCC, product name: Multiplus) so that the dry film thickness is 33㎛, and blow hot air at 80°C for 30 minutes to harden. A final coating film was formed. The physical properties of the final coating film were measured in the following way, and the results are shown in Table 4.

(1) Content of volatile organic compounds

The primer compositions of Examples and Comparative Examples were measured by the method specified in ASTM D3960 (Practices for determining Volatile Organic Compound (VOC) content of paints).

(2) specific gravity

Specific gravity was measured using a specific gravity cup at 25 ℃.

(3) solid content

After leaving the primer compositions of Examples and Comparative Examples at 150° C. for 30 minutes, the solid content was measured by measuring the nonvolatile matter.

(4) Viscosity

Podcup viscosity was measured based on No. 4 Podcup at 25°C.

(5) Adhesiveness

Based on the content described in ASTM D3359, 100 squares (width 2mm x length 2mm) were drawn on the final coating film with a blade, respectively, and removed using a tape to measure adhesion. At this time, adhesion was evaluated according to the standards described in ISO 2409.

6) Water resistance

After leaving the specimen coated with a primer and oil-soluble clear paint (manufacturer: KCC, product name: Multiplus) at room temperature for 3 days, it was immersed in a water bath at 40°C for 10 days to check adhesion and appearance. Adhesion was evaluated in the same manner as in item (5), and the appearance of the blister was visually checked.

VOC(g/L) importance solid content
(weight%) Viscosity (sec) adherence water resistance adherence Exterior Example 1 673.2 0.96 11.8 12.9 M1.5 M2.0 no blister Example 2 675.1 0.95 12.1 13.2 M1.5 M2.5 no blister Example 3 674.3 One 11.9 13.09 M2.0 M3.0 no blister Example 4 678.8 1.02 12 13.3 M2.5 M3.0 no blister Example 5 676.4 0.95 12 13.1 M1.5 M2.5 no blister Example 6 673.8 1.02 12.8 13.99 M2.5 M2.5 no blister Example 7 676 One 12.3 13.49 M2.0 M3.0 no blister Example 8 673.5 0.96 11.8 12.9 M2.0 M2.5 no blister Example 9 674.7 1.02 12 12.98 M1.5 M2.0 no blister Example 10 677.9 One 12.1 13.29 M2.5 M3.0 no blister Comparative Example 1 675.9 0.96 11.8 12.9 M1.5 M2.5 with blister Comparative Example 2 677.6 1.02 12 12.98 M4 M5 with blister Comparative Example 3 865 0.95 12.1 13.4 M1.5 M2.5 no blister

As shown in Table 4, the coating compositions of Examples 1 to 10 had a volatile organic compound content of 680 g/L or less. Specific gravity, solid content, viscosity, adhesion and water resistance were excellent.

On the other hand, in Comparative Example 1 to which no epoxy resin was applied, Comparative Example 2 to which no olefin resin was applied, and Comparative Example 3 to which no solvent was used exempt, the content of volatile organic compounds exceeded 680 g/L, or adhesion and water resistance This was lacking.

Claims (5)

Contains a chlorinated polyolefin-based resin, an epoxy resin, a pigment and a solvent,
The solvent comprises an exempt solvent,
The exempt solvent includes a ketone-based solvent,
The chlorinated polyolefin-based resin has an acid content of 1 to 2% by weight based on the total weight of the chlorinated polyolefin-based resin, a chlorine content of 22 to 27% by weight, and a weight average molecular weight of 55,300 to 69,100 g/mol, and at 25°C has a viscosity of 15 to 40 mPa s,
The epoxy resin has a glass transition temperature (Tg) of 10 to 20 °C, an epoxy equivalent of 160 to 200 g / eq, and a weight average molecular weight of 760 to 1,280 g / mol,
The ketone-based solvent is a primer composition comprising dimethyl carbonate,
The composition comprises 1 to 10 parts by weight of a chlorinated polyolefin-based resin, 0.1 to 5 parts by weight of an epoxy resin, 1 to 10 parts by weight of a pigment, and 10 to 28 parts by weight of dimethyl carbonate. delete The method according to claim 1,
The epoxy resin has a viscosity of 8,000 to 20,000 cps at 25°C, a primer composition. delete delete