KR100785224B1 - Coating composition - Google Patents

Abstract

The present invention relates to a coating composition comprising a polyisocyanate compound, a hydroxyl-functional film-forming polymer and a non-volatile branched monoalcohol,

Aliphatic branched monoalcohols are preferred, and long chain nonvolatile branched monoalcohols are more preferred. This allows the coating composition to exhibit improved flow behavior and to produce coatings with improved appearance without adversely affecting other properties. The invention also relates to a multicomponent coating composition. Preferably the multicomponent coating composition is a two component coating composition comprising a polyisocyanate component and a hydroxyl-functional film-forming polymer, and also comprises a nonvolatile branched monoalcohol. Finally, the present invention relates to the production of multilayer coatings and the use of coating compositions used in the refinishing industry.

Description

Coating Composition {COATING COMPOSITIONS}             

It is industrially to improve the flow behavior of coating compositions comprising polyisocyanate compounds and hydroxyl-functional film-forming polymers and to improve the appearance of the coatings while maintaining other properties of the coating compositions and coatings formed from the coating compositions. Has been required. It has been found that non-volatile branched monoalcohols can provide the desired improvements. Particularly useful are long chain straight monoalcohols having 12 or more carbon atoms. Since monoalcohols having 12 or more carbon atoms are usually solid at room temperature, their use in coating compositions is believed to be limited. Surprisingly, it has been found that several long chain nonvolatile branched monoalcohols are suitable as additives in coating compositions, in particular in multicomponent (at least two component) coating compositions. This improved the flow behavior of the coating composition and could produce coatings with improved appearance without unacceptably adverse effects on other properties.

Coating compositions comprising polyisocyanates and polyols are disclosed, for example, in European Patent Application No. 0219131. The document also discloses the use of various purpose coating compositions including top coatings of relatively heavy weight articles such as carriers, industrial machinery and building and structural machinery.                 

Rapid setting and rapid curing of coating compositions with acrylic binders having a high Tg are disclosed, for example, in US Pat. No. 5,741,880 and US Pat. No. 5,759,631. The combination of low viscosity polyols and hard acrylics is disclosed in US Pat. No. 5,286,782. In order to obtain a coating composition with low VOC, acetone, methyl acetate and tert-butyl acetate can be added as a fast evaporating solvent with a low photochemically reactive solvent. The combination of acrylic binder and rapid evaporation solvent results in poor flow and appearance. In order to improve the flow and appearance, large amounts of low viscosity polyols are sometimes added, but they are slow to cure and poorly set.

US 4,235,766 discloses a coating composition comprising an organic polyhydroxy compound and an organic polyisocyanate. The coating composition also includes 2-methyl-2-propanol and / or 2-methyl-2-butanol. The monoalcohol is a volatile compound. A disadvantage of using volatile compounds is that they cannot control how much compound is added to the coating after application of the coating composition and how much evaporation and contribution to the VOC of the coating composition.

Summary of the Invention

The present invention relates to a coating composition comprising a polyisocyanate compound, a hydroxyl-functional film-forming polymer and a non-volatile branched monoalcohol. Aliphatic branched monoalcohols are preferred.

The invention also relates to a multi-component coating composition. Preferably, the multicomponent coating composition is a bicomponent coating composition comprising a polyisocyanate component and a hydroxyl-functional component, wherein the hydroxyl-functional component as well as the hydroxyl-functional film forming polymer are non- Volatile branched monoalcohols are also included. Non-volatile branched monoalcohols can be mixed with the hydroxyl-functional film forming polymer or added during the preparation of the hydroxyl functional film forming polymer.

Certain nonvolatile branched aliphatic monoalcohols can be used in the present invention. Preferably the nonvolatile branched aliphatic monoalcohols used in the present invention have at least 12 carbon atoms, more preferably at least 16 carbon atoms. Also mixtures of nonvolatile branched monoalcohols having at least 12 carbon atoms on average may be used, and more preferably mixtures of nonvolatile branched monoalcohols having at least 16 carbon atoms on average. Preferably Guerbet alcohol or mixtures of Guerbet alcohols are used, more preferably Guerbet alcohols (or mixtures of Guerbet alcohols having at least 12 carbon atoms on average), most preferably at least Guerbet alcohols having 16 carbon atoms (or mixtures of gerbet alcohols having at least an average of 16 carbon atoms) are used. Guerbet alcohols are branched primary alcohols, straight chain, have two carbon chains, and the branch point is always at the second carbon position.

The hydroxyl-functional film forming polymer preferably has a hydroxyl value of 50 to 300 mg KOH / g, more preferably 70 to 200 mg KOH / g, based on solids.

The number average molecular weight of the polymer is preferably less than 6000, more preferably less than 4500 as determined by gel permeation chromatography with polystyrene as standard. Molecular dispersity, for example, the ratio of Mw to Mn is preferably in the range of 1.1 to 5, with the range of 1.1 to 3 being particularly preferred. The acid value of the polymer is preferably between 0 and 50 mg KOH / g based on solids. The Tg of the acrylic polyol is preferably at least 25 ° C, more preferably at least 40 ° C, most preferably between 60 and 110 ° C.

The hydroxyl-functional film forming polymers include, but are not limited to, polyesters, polyacrylates, polyvinyls, polyurethanes, polycarbonates or polyamides, with acrylic polyols being preferred. The acrylic polyols are hydroxy-functional acrylic monomers such as hydroxy ethyl (meth) acrylate, hydroxy propyl (meth) acrylate, hydroxy butyl (meth) acrylate, other acrylic monomers such as (meth) With acrylic acid, methyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobornyl (meth) acrylate, trimethyl cyclohexyl (meth) acrylate and optionally vinyl derivatives For example, in combination with styrene or the like or mixtures thereof, wherein (meth) acrylate and (meth) acrylic acid represent methacrylate and acrylate, and methacrylic acid and acrylic acid, respectively. The acrylic polyols are prepared by conventional methods, for example by slowly adding the appropriate monomers to a solvent solution of a suitable polymerization initiator such as azo or peroxy initiator.

When a non-volatile branched mono alcohol is added during the preparation of the hydroxyl-functional film forming polymer, preferably during the production of the acrylic polyol, the monoalcohol is added to the reaction vessel before starting the polymerization reaction. Preference is given to adding with the solvent.

The weight ratio of nonvolatile branched monoalcohol to solid hydroxyl-functional film forming polymer is preferably 1:99 to 50:50, more preferably 5:95 to 25:75.

Polyisocyanates useful herein as polyisocyanate compounds and polyisocyanate components include polyisocyanates having two or more, preferably 2 to 4 isocyanate groups. Examples of non-limiting polyisocyanates used in the present invention include toluene diisocyanate, methylene bis (4-cyclohexyl isocyanate), isophorone diisocyanate and its isocyanurates or adducts thereof, hexamethylene diisocyanate and isocyanurs thereof Latex, biuret, uretdione and allophanates and adducts thereof with meta-tetramethylxylene diisocyanate and trimethylolpropane.

The polyisocyanate compound is used in an amount such that the ratio of the total number of isocyanate groups to hydroxyl groups in the coating composition is preferably in the range from 0.8 to 2.

The solvent may be part of a hydroxyl functional component, a polyisocyanate component and / or may be a separate reducer. In particular, the diluent in a multicomponent system may be one of the components. In a multicomponent system comprising a polyisocyanate component, a hydroxyl functional component and a third component, the diluent may be a third component.

The coating composition may include, for example, dibutyl tin dilaurate, triethyl amine, and the like as a catalyst for the isocyanate-hydroxyl reaction. The coating composition may also include a pigment. In addition to organic pigments, inorganic pigments may be used. The composition may also include conventional additives such as stabilizers, surfactants, fillers, UV-absorbers, catalyst blockers, antioxidants, colorant dispersants, flow additives, flow control agents, leveling agents and solvents. The solvent is a specific solvent known to those skilled in the art, for example, may be aliphatic and / or aromatic hydrocarbons. Examples include Solvesso 100, Exxate 600, toluene, xylene, 4-chloro-benzotrifluoride, butanol, isopropanol, butyl acetate, tert-butyl acetate, ethyl acetate, methyl acetate, memeth Methoxy propyl acetate, n-butyl propionate, ethoxyethylpropionate, acetone, methyl isobutyl ketone, methyl isoamyl ketone, methyl ethyl ketone, ethers, ether alcohols and ether esters or mixtures thereof.

Preferably the coating composition comprises less than 550 g / l, more preferably less than 500 g / l and most preferably less than 480 g / l based on the total composition.

The invention also relates to a multicomponent coating composition. The multicomponent coating composition comprises at least two components, for example a hydroxyl-functional component and a polyisocyanate component. Preferably, the multicomponent coating composition comprises three components with a third component comprising a solvent to provide a sprayable viscosity to the coating composition, such as a diluent.

The coating composition of the present invention may be applied to certain substrates. The substrate may for example be a metal, plastic, wood, glass, ceramic or other coating layer. The other coating layer may comprise the coating composition of the present invention or may be another coating composition. Coating compositions of the present invention have particular uses, such as clearcoats, basecoats, colored topcoats, primers and fillers. The coating composition may be applied using conventional means such as a spray gun, brush or roller, with spraying being preferred. The curing temperature is preferably between 0 and 80 ° C, more preferably between 20 and 60 ° C. The compositions are particularly suitable for producing coated metal substrates, for example in the refinish industry, in particular in automotive supply stores, in repairing automobiles and vehicles, and in large vehicles such as trains, trucks, buses and aircraft. Used to finish

The coating composition of the present invention is preferably used as a clear cord. Clearcoats must be very transparent and adhere well to the basecoat layer. The clearcoat should also not alter the aesthetic aspects of the basecoat, such as discoloration of the basecoat with a solvent present in the clearcoat composition or yellowing of the clearcoat due to exposure outdoors. Clearcoats based on the coating compositions of the present invention do not have this drawback.

Accordingly, the present invention provides a method of selectively applying a basecoat composition on a coated substrate, optionally curing the basecoat, applying a clearcoat composition according to the invention on top of the basecoat, and curing a multilayer coating. It relates to a method for producing a multilayer coating comprising a step.                 

If the coating composition is a clearcoat, the basecoat can be a conventional basecoat known in the coating materials art. Examples are solvent-based basecoats, for example Autobase (trade name), manufactured by Akzo Nobel Coatings) and aqueous basecoats, for example Autowave (trade name), manufactured by Akzo Nobel Coatings. The basecoat may also include pigments (color pigments, metals and / or pearls), waxes, solvents, flow additives, neutralizers and antifoaming agents. High-solid basecoats can also be used. For example based on polyols, imines and isocyanates. The clearcoat composition is then applied to the basecoat surface and cured. An intermediate curing step for the basecoat can be introduced.

The invention will be further illustrated by the following specific but non-limiting examples.

Example 1

Acrylic polyols 1

Acryl polyol 1 was added by adding 700 g of n-butyl propionate to a 5-liter four-necked round bottom flask with stirrer, condenser, heating grid, thermocouple with thermowatch, nitrogen and additive inlet Are manufactured. The solvent is heated to reflux at 145-150 ° C. under a blanket of nitrogen.

When the temperature reaches reflux, 145-150 ° C. and stabilizes, the following mixture is added to the top of the flask over 180 minutes: 600 g of styrene, 800 g of tert-butyl methacrylate, 200 g of n-butyl methacrylate Rate, 400 g of 2-hydroxyethyl methacrylate and 79 g of tert-butyl peroxy-3,5,5-trimethylhexanoate. During the addition of the mixture, the reaction temperature is maintained at reflux under a nitrogen blanket. After the addition was completed, the addition line was initially washed with 50 g of n-butyl acetate and chaser addition of 50 g of n-butyl acetate and 1.0 g of tert-butyl peroxy-3,5,5-trimethylhexanoate Wash with mixture. The reaction temperature is maintained at reflux for an additional hour. Finally 320 g of n-butyl acetate are added as extractant.

The resulting solution of higher solid acrylic polyol 1 had a nonvolatile content of 64.3%, a Brookfield viscosity of 3,800 cps (25 ° C., spindle 4 and 20 RPM) and a hydroxyl value of 86.3 (mg KOH in solid phase). / g). The molecular weight of the polymer is determined using Waters's Associates gel permeation chromatography (GPC) and Phenomenex polystyrene standards. The higher solid acrylic polyol 1 has a Mn of 3,020, a Mw of 8,134, a dispersion degree (D) of 2.69 and a theoretical Tg of 87 ° C.

Hydroxyl-functional component 1

Hydroxyl-functional component 1 is prepared by mixing the following:

74.3 g of acrylic polyol 1 prepared above

Guerbet alcohol having 18 carbon atoms (ISOFOL 18T manufactured by CONDEA Chemie GmbH, Hamburg, Germany) 4.2 g

Butyl Acetate 8.0g                 

Acetone 8.8 g

0.1 g dibutyl tin dilaurate (10% in butyl acetate)

1.7 g of flow additive (byk 310 manufactured by Byk Chemie, 10% in xylene)

1.4 g of UV stabilizer (Tinuvin 292, manufactured by Ciba) and

1.4 g of UV stabilizers (Tinuvin 1130, manufactured by Ciba).

Polyisocyanate Component 1

The following components are mixed to make Polyisocyanate Component 1:

55 g of isocyanurate of hexane diisocyanate (90% in butyl acetate, Desmodur N3390 from Bayer),

Xylene 16.2 g

16.8 g of methoxypropyl acetate and

Butyl Acetate 11.4g

Thinner 1

The following ingredients are mixed to make Diluent 1:

Acetone 22.8 g

13.5 g of methoxypropyl acetate and

Exate 600 63.7 g

Formation and Use of Coating Composition 1

The hydroxyl-functional component 1, the polyisocyanate component 1 and the diluent 1 are mixed in a volume ratio of 100: 50: 30 to prepare a clear top coat of the coating composition according to the invention. In the first step, polyisocyanate component 1 and diluent 1 are mixed together. In a second step, hydroxy-functional component 1 is added. The clear top coat had a VOC of 4.0 lb / gal excluding acetone. The crosslinking ratio of NCO: OH is 1.4.

In order to evaluate the present invention, the test piece was first applied with a Colorbuild (trade name) sealant (manufactured by Akzo Nobel Coatings) and sprayed with an autobase (trade name) base coat (manufactured by Akzo Nobel Coatings). The clear top coat prepared above is sprayed onto the prepared test piece. The properties of the clear top coating composition and the resulting coatings are set forth in Table 1 below.

Comparative Examples A and B

To demonstrate that the present invention has improved flow and appearance, Comparative Example A repeats Example 1, but excludes nonvolatile branched aliphatic monoalcohols; That is, Guerbet alcohol does not exist. In Comparative Example B, the nonvolatile branched aliphatic monoalcohol is replaced with a 80% polyester polyol solution in Desmodeu 670, butyl acetate from Bayer.

Comparative Example A

Hydroxyl-functional component A

The hydroxyl-functional component A is prepared by mixing the following:

80.8 g of the acrylic polyol 1 prepared above.

Butyl Acetate 5.7g

Acetone 8.8 g                 

0.1 g dibutyl tin dilaurate (10% in butyl acetate)

1.7 g of flow additive (byk 310 10% in xylene, manufactured by Byk Chemie)

1.4 g of UV stabilizer (tinuvin 292, manufactured by Ciba) and

1.4 g of UV stabilizers (Tinuvin 1130, manufactured by Ciba).

Coating Composition A and Use

Coating composition A is prepared and used in the same manner as in Example 1, except that hydroxyl-functional component A is used. VOC is 4.0 lb / gal excluding acetone. The crosslinking ratio is 1.4. The properties of the coating compositions of Comparative Example A and the resulting coatings are set forth in Table 1 below.

Comparative Example B

Hydroxyl-functional component B

The hydroxyl-functional component B is prepared by mixing the following:

74.3 g of acrylic polyol 1 prepared above (70% in methyl amyl ketone)

5.3 g Desmophene 670 (80% in butyl acetate)

Butyl Acetate 6.9g

Acetone 8.8 g

0.1 g dibutyl tin dilaurate (10% in butyl acetate)

1.7 g of flow additive (byk 310 10% in xylene, manufactured by Byk Chemie)

1.4 g of UV stabilizer (tinuvin 292, manufactured by Ciba) and

1.4 g of UV stabilizers (Tinuvin 1130, manufactured by Ciba).                 

Coating Composition B and Uses

Coating composition B is prepared and used in the same manner as in Example 1, except that hydroxyl-functional component B is used. VOC is 4.0 lb / gal excluding acetone. The crosslinking ratio is 1.4. The properties of the coating compositions of Comparative Example B are set forth in Table 1 below.

Property Method (unit) Example 1 Comparative Example A Comparative Example B Viscosity @ 70 ℉ DC4 (sec) 13.9 15.7 15.1 Viscosity after 2 hours DC4 (sec) 23.2 20.3 21.2 Ease of operation @ 60 ℃ Manual (minutes) 36 29 35 1 day longitude Persoz (seconds) 62 59 52 7 days longitude Persoz (seconds) 151 159 124 DOI (7 days) 85 75 75 Appearance Naked eyes (3 people) 8.5 6.5 6.7 S short wavelength Wave Scan (Byk) 4.9 10.3 10.3 L long wavelength Wave Scan (Byk) 31.1 33.2 34.1

As demonstrated by the data set forth in Table 1 above, the use of non-volatile branched monoalcohols provides excellent flow and appearance while maintaining other desirable properties in the coating compositions of the present invention.

Example 2

Acrylic polyol 2

Acrylic polyol divalent stirrer, condenser, heating grid, thermoelectric pair with thermowatch, 5 l eggplant four round bottom flask with nitrogen and additive inlet, 200 g n-butyl propionate and 500 g gerbe alcohol , For example by adding Isofol 18T. The mixture is heated to 150 ° C. under a blanket of nitrogen.

Upon reaching a temperature of 150 ° C., the following mixture is added to the top of the flask over 180 minutes: 1000 g of styrene, 200 g of tert-butyl methacrylate, 400 g of n-butyl methacrylate, 400 g of 2-hydrate Oxyethyl methacrylate and 98 g tert-butyl peroxy-3,5,5-trimethylhexanoate. During the addition of the mixture, the reaction temperature is maintained at reflux under a nitrogen blanket. After the addition was completed, the addition line was initially washed with 50 g tert-butyl acetate and chaser addition of 50 g tert-butyl acetate and 1.0 g tert-butyl peroxy-3,5,5-trimethylhexanoate Wash with mixture. The reaction temperature is maintained at 150 ° C. for an additional hour. Finally 814 g tert-butyl acetate is added as extractant.

The resulting solution of the higher solid acrylic polyol 2 had a non-volatile content of 70.1%, a Brookfield viscosity of 65, at 1,800 cps (reduced with tert-butyl acetate at 25 ° C., spindle 4 and 20 RPM) and a hydroxide of 112.7. Have a real value (mg KOH / g on solids). The molecular weight of the polymer is measured using Water's Combination Gel Permeation Chromatography (GPC) and Phenomenex Polystyrene Standards. The higher solid acrylic polyol 2 has a Mn of 3,750, Mw of 8,430, and a dispersion degree (D) of 2.2.

Hydroxyl-functional component 2

Hydroxyl-functional component 2 is prepared by mixing the following:

67.9 g of the acrylic polyol 2 prepared above

Ethoxyethyl propionate 10.0g                 

Acetone 13.8 g

0.1 g dibutyl tin dilaurate (10% in butyl acetate)

1.7 g of flow additive (byk 310 10% in xylene, manufactured by Byk Chemie)

1.4 g of UV stabilizer (tinuvin 292, manufactured by Ciba) and

1.4 g of UV stabilizers (Tinuvin 1130, manufactured by Ciba).

Hydroxyl-functional component 3

Hydroxyl-functional component 3 is prepared by mixing the following:

68.8 g of the acrylic polyol 1 prepared above

Guerbet Alcohol, eg Isopol ™ 18T 12.5 g

3.5 g of ethoxyethyl propionate

Acetone 12g

0.2 g dibutyl tin dilaurate (10% in butyl acetate)

0.4 g of flow additive (byk 310, 10% in xylene, manufactured by Byk Chemie)

1.3 g of UV stabilizer (tinuvin 292, manufactured by Ciba) and

1.3 g of UV stabilizers (tinuvin 1130, manufactured by Ciba).

Polyisocyanate Component 2

The following ingredients are mixed to prepare a curing agent:

70 g of isocyanurate of hexane diisocyanate (Desmodeu N3600, made by Bayer),

30 g tert-butyl acetate

Polyisocyanate Component 3

65 g of isocyanurate of hexane diisocyanate (Desmodeu N3600, manufactured by Bayer),

35 g of 4-chloro-benzotrifluoride

Formation and Use of Coating Compositions 2 and 3

The hydroxyl-functional component 2, the polyisocyanate component 2 and the diluent are mixed in a volume ratio of 100: 50: 30 to prepare Clearcoat 2 of the coating composition according to the invention. tert-butylacetate is used as diluent in coating composition 2. Clearcoat 3 is prepared in the same way, except 4-chloro-benzotrifluoride is used as diluent. The clearcoat had a VOC of 2.0 lb / gal excluding exempt solvent from a spray viscosity of DC4 of 13-14 seconds.

In order to evaluate the present invention, the test piece was first applied with a color build sealant (manufactured by Akzo Nobel Coatings) and sprayed with an autobase (trade name) base coat (manufactured by Akzo Nobel Coatings). The clearcoat prepared above is sprayed onto the prepared test piece. The clearcoats exhibit good flow and appearance.

Claims (32)

As a coating composition, Polyisocyanate compounds, hydroxyl-functional film-forming polymers and branched non-volatile monoalcohols, Wherein said hydroxyl-functional film-forming polymer is an acrylic polyol and said branched non-volatile monoalcohol is a Guerbet alcohol. The method of claim 1, A coating composition further comprising a diluent. The method of claim 1, The coating composition of the monoalcohol is 12 or more carbon atoms on average. The method of claim 1, Coating composition, characterized in that the monoalcohol has an average of 16 or more carbon atoms. The method of claim 1, Coating composition, characterized in that the weight ratio of monoalcohol to solid acrylic polyol is from 1:99 to 50:50. The method of claim 5, The weight ratio is 5:95 to 25:75 coating composition, characterized in that. The method of claim 1, Coating composition, characterized in that the Tg of the hydroxyl-functional film-forming polymer is at least 25 ℃. The method of claim 7, wherein The Tg is a coating composition, characterized in that 40 ℃ or more. The method of claim 1, Branched non-volatile monoalcohol is a coating composition, characterized in that aliphatic. The method of claim 1, Wherein the hydroxyl-functional film-forming polymer is prepared in the presence of a branched non-volatile monoalcohol. A multicomponent coating composition comprising a polyisocyanate component and a hydroxyl-functional component, The hydroxyl-functional component further comprises a branched non-volatile monoalcohol, which is a Guerbet alcohol, in addition to the hydroxyl-functional film-forming polymer which is an acrylic polyol. Coating composition. The method of claim 11, And a third component, which is a diluent. The method of claim 11, The monoalcohol has an average of 12 or more carbon atoms. The method of claim 11, The monoalcohol has an average number of carbon atoms of 16 or more. The method of claim 11, And wherein the weight ratio of monoalcohol to solid acrylic polyol is from 1:99 to 50:50. The method of claim 15, The weight ratio is 5:95 to 25:75 multicomponent coating composition, characterized in that. The method of claim 11, And wherein the Tg of the hydroxyl-functional film-forming polymer is at least 25 ° C. The method of claim 17, The Tg is a multi-component coating composition, characterized in that more than 40 ℃. The method of claim 11, Branched chain non-volatile monoalcohol is a multicomponent coating composition, characterized in that aliphatic. The method of claim 11, Wherein the hydroxyl-functional film-forming primer is prepared in the presence of a branched non-volatile monoalcohol. As a refinishing method of the car, A refinishing method comprising the step of applying the coating composition according to claim 1 to an automobile. As a refinishing method of the car, A refinishing method comprising the step of applying the multicomponent coating composition according to claim 11 to a motor vehicle. A clearcoat composition comprising the coating composition of claim 1. A clearcoat composition comprising a coating composition according to claim 11. As a method for producing a multilayer coating material, A process comprising the following processes (a) and (b): (a) applying a basecoat composition to a substrate; (b) applying a clearcoat composition according to claim 1 on top of the basecoat, and curing the multilayer coating material. As a method for producing a multilayer coating material, A process comprising the following processes (a) and (c): (a) applying the basecoat composition to a coated or uncoated substrate; (c) applying the clearcoat composition according to claim 11 on top of the basecoat and curing the multilayer coating material. The method of claim 25, The substrate is coated before applying the basecoat of step (a). The method of claim 26, Before applying the clearcoat in step (c), further comprising curing the basecoat applied in step (a). delete delete delete delete