JPS6027702B2 - acrylic coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION There are many areas where it is desirable to use acrylic polymer overcoats for protection and aesthetic reasons.

There are two general methods for making protective or decorative acrylic coatings. One is solution based and the other is based on non-aqueous dispersible polymers. The first method by which acrylic polymers were commercially introduced in coatings was based on traditional solution polymerization of acrylic monomers. Two types of acrylic polymers have been widely used, both in solution and dispersion.

The first are thermoplastic non-crosslinked systems used as lacquers. The second is a thermosetting acrylic dispersion, which is a crosslinked system based on a polymer with hydroxyl functionality cured with a melamine-formaldehyde resin. Both types of solution polymers are formulated by methods well known in the art. Ingredients used in the formulation of coatings based on acrylic solution polymers typically include pigments, fillers, plasticizers, flow aids, additional solvents, diluents and other materials that impart the desired properties to the coating solution and coating film. including other substances used together to give For economic reasons, it is important that coating compositions can be applied quickly and efficiently.

Especially in the constant search for higher production in industry.
A coating application method that produces a standard film thickness and yields a serviceable coating in two coats instead of three or more coats is:
Clearly a desirable goal when applying coatings productively. As mentioned above, a second, more modern method is based on non-aqueous dispersion polymers.

This polymer, as currently introduced, is made by heating an acrylic monomer polymer in the presence of a catalyst along with a dispersion stabilizer in an organic solvent in which the formed polymer is substantially indestructible. Non-aqueous dispersion polymers made by methods known in the art are desirable because they are easily poured, form essentially non-viscous liquids, and also have a substantially higher non-volatile content than solution polymers. . The formulation of non-aqueous dispersion polymers into coatings is quite different from the formulation used with solution polymers.

In order to retain the advantages of non-aqueous dispersion technology of non-aqueous dispersion coatings during manufacture, storage, and application, they are treated essentially as particulate dispersions. In contrast to solution coatings, non-aqueous dispersion coatings are formulated to account for and preserve the biphasic nature of the dispersion polymer used during their manufacture, storage, and application. The solvent/diluent (non-solvent) ratio is chosen in relation to the evaporation rate such that more rapid evaporation of the diluent increases the percentage of solvent by spray penetration of the coating. Finally, since the coating is subjected to calcination temperatures common in industrial coating operations, 2
The phase-dispersed polymers coalesce to form an integral coating.
As used herein, the active solvent refers to a solvent that dissolves the copolymerization reaction product, and is to be contrasted with a diluent or non-solvent (also referred to herein as a non-active solvent) that does not dissolve the copolymerization reaction product. used. Obviously, non-aqueous dispersions are not designed to be impregnated with an active solvent to convert the dispersion into solution form.

This eliminates the benefits of non-water content materials such as low viscosity, high solids, non-smog forming and inexpensive diluents. Furthermore, since this soaked dispersion is expected to have the same properties as the solution, it is unwise to incur the additional expense and time required to initially create a non-aqueous dispersion. A particular disadvantage of non-aqueous dispersions is that the presence of coalescence during storage can cause the dispersion to gel or otherwise destroy its physical properties, rendering it unusable.

One method and the most current method of improving the poor storage stability of non-aqueous dispersion coatings is to precisely balance the diluent (non-solvent) content with the active solvent and/or plastic composition present. It is to let

Some solutions to the problem of stability of non-aqueous dispersion coatings include the use of more effective dispersion stabilizers to better protect the polymer particles against dissolution and gelation. This has not been completely successful. All of these secondary solutions alleviate some of the problems encountered in formulating coatings from both solution and non-aqueous dispersion polymers.

The growth of the organic coatings industry in recent years is one indicator of the progress that has been made. In the automotive industry, which is one of the important applications for acrylic coatings, the problems described above involving solution and non-aqueous dispersion coatings are particularly urgent.

Competitive pressures demand the most efficient use of labor and materials in the production and finishing of automobiles. It is therefore important to make production lines economical and to be able to increase the speed of complete unit operations such as painting. For example 3
An overcoat finish that can achieve the same protective film thickness and aesthetics with two spray applications is considered a valuable variation when spraying or more is the standard method. Prior to this invention, commercial thermoset acrylic enamel overcoats required at least three applications of mists to deposit a film of the required thickness and appearance, especially when pigments were added, including metal flakes. did.

The present invention relates to solving the above problems, and further aims to realize the following advantages. The present invention primarily focuses on thermosetting acrylic enamels such as increased coating efficiency, the ability to provide satisfactory coverage in two coats instead of three, high gloss, and superior metallic pattern control to provide an aesthetic appearance. Regarding improvements.

An unsaturated monomer containing a hydroxyl group (described later) is polymerized in the presence of a polyfunctional dispersion stabilizer in a non-solvent for the polymer, and then an active solvent is added which would actually form a solution in the absence of a microgel. Solutions of thermoset polymer particles containing twilled microgel particles can be sprayed to high film build-up in two coats, increasing coating efficiency and resulting coatings with significantly improved resistance to solvent bulging and high gloss. It was found that it has pattern control.

The acrylic monomers polymerized in the non-water-free polymers of the present invention contain from about 4 to about 3 weight percent hydroxyl group-containing compounds.

Examples of hydroxyl group-containing polymeric monomers are oxyalkyl acrylates and oxyalkyl methacrylates, such as 2-oxyethyl acrylate, 2-oxypropyl acrylate, 4-oxybutyl acrylate, oxyhexyl acrylate, oxyoctyl acrylate,
-oxyethyl methacrylate, 2-oxypropyl methacrylate, 4-oxybutyl methacrylate, oxyhexyl methacrylate, oxyoctyl methacrylate, etc. Preferred hydroxyl-containing alkyl acrylates contain up to about 8 carbon atoms in the alkyl group. The hydroxyl-containing acrylic monomer can be copolymerized with other polymerizable monomers to form a polymer dispersion, so long as the final polymer contains at least about 4% by weight of the hydroxyl-containing monomer.

Examples of other monomers that can be copolymerized with the hydroxyl group-containing monomer include:
Q,8-ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid. Esters of these acids, such as butyl acrylate, 2-ethylhexyl acrylate, octyl methacrylate, and lauryl methacrylate, can also be copolymerized with the hydroxyl group-containing monomer. Other copolymerizable monomers such as styrene, methyl methacrylate, methyl acrylate, ethyl acrylate, butyl methacrylate, etc. can also be used. Preferably, the monomer system should also include an ethylenically unsaturated carboxylic acid in order to impart compatibility to the resulting polymer. Preferably, the monomer system contains from about 0.5 to about 1% by weight of the acid. The ethylenically unsaturated monomer is polymerized in a dispersion liquid that solubilizes the monomer but leaves the resulting polymer essentially insoluble, forming dispersed polymer particles.

The non-solvent is generally a hydrocarbon medium consisting essentially of liquid aliphatic hydrocarbons. Pure aliphatic hydrocarbons or mixtures of two or more can be used. To the extent that the particular polymer produced is largely insoluble in the hydrocarbon medium, essentially aliphatic hydrocarbons can be modified by incorporating other solvent materials, such as aromatic or naphthenic hydrocarbons. In some cases, the amount of the non-aliphatic component can be as much as 4% by weight of the total liquid medium. However, it is preferred that the liquid medium consist essentially of aliphatic hydrocarbons, and generally the compositions of the present invention will contain no more than 25% by weight of aromatic hydrocarbons, based on the weight of the liquid medium, and at this stage no aromatic hydrocarbons. Not included. Hydrocarbons must be liquid in nature, but have a wide boiling point range from a minimum of about 30 qo (in which case high pressures may be required for polymerization) to a maximum of about 300 qo. I can do it.

For large-scale purposes, the boiling point should be from about 5000 to about 235 qC. The boiling point or boiling point range of the liquid hydrocarbon system can be selected to suit the particular operation in which the polymer dispersion made in the hydrocarbon is to be used. Thus, for coating or impregnation operations intended to be carried out in low temperature climates, liquid hydrocarbon media having relatively low boiling points, such as about 30-3500, are preferred. For pressurized systems such as aerosol atomization, similar boiling points can be chosen. On the other hand, if the coating and impregnating operations are to be carried out in relatively high temperature drying ovens or equipment with rolls, the hydrocarbon system can have an extremely high boiling point, such as 275-30,000. Examples of non-solvents useful herein are pentane, hexane, heptane, octane, mixtures thereof, and the like. Generally, the polymerizable composition of monomer and non-solvent should contain from about 30 to about 8 weight percent non-solvent.

However, it will be appreciated that the monomer solution must contain as much non-solvent as is necessary to solubilize the monomer and maintain the resulting polymer in a dispersed state after polymerization. The above monomers are polymerized in the presence of a dispersion stabilizer.

The dispersion stabilizer initiated by this invention is a branched copolymer consisting of two types of polymeric components, one segment of which is solvated by an aliphatic hydrocarbon solvent and a polymerizable ethylenically unsaturated It is not normally associated with polymerized particles of monomer. The second type of component is also an anchor polymer with a different polarity than the first type.
It is relatively nonsolvable with aliphatic hydrocarbon solvents and can be fixed with polymerized particles of ethylenically unsaturated monomers. The anchoring polymer described above contains an ethylenically unsaturated monomer and a copolymerizable bulge group. This dispersion stabilizer consists of two segments. The first segment is characterized by: '1) the lowest chain hydrocarbon molecule that can be solvated by the dispersion liquid and contains an unterminated reactive group, and [2] copolymerizable with the ethylenically unsaturated monomer to be polymerized. It consists of a reaction product with an ethylenically unsaturated compound containing a functional group capable of reacting with the terminal reactive group of a long mirror hydrocarbon molecule '1'. Generally, the solvating segment sails will have about 300 to about 3,
It is a monofunctional polymeric material with a molecular weight of 0.000. This polymer can be made, for example, by a polyester or polytel forming condensation reaction. Preferably, the polyester reaction is a simple reaction involving monohydric monocarboxylic acid monomers; such reactions lead to components that are strictly monofunctional with respect to one or the other group. The most convenient monomers to use are oxyacids that form oxyacid polymers. For example, oxyfatty acids such as 12-oxystearic acid can be polymerized to form non-polar components that can be solvated by non-polar organic liquids such as aliphatic and aromatic hydrocarbons. Next, this polyoxystearic acid,
It can be reacted with a compound copolymerizable with the acrylic monomer to be polymerized, such as glycidyl acrylate or glycidyl methacrylate. The glycidyl groups react with the carboxyl groups of polyoxystearic acid to form polymer segment molecules. A preferred polymeric segment of the dispersion stabilizer (1) is formed by the reaction of poly(12-oxystearic acid) with glycidyl methacrylate.

The second polymer segment leg of the dispersion stabilizer has a different polarity than the first segment, and is relatively non-solvable by the dispersion liquid as is, and the acrylic polymer formed by polymerization It contains a bulbous group that can be associated with the particles or fixed within the polymer particles and copolymerizable with the acrylic monomer.

This fixed segment 'B}' is around the polymerized particle 1
This provides a layer of stabilizer. The solvated polymer segments pushing outward from the surface of the particles provide a solvation barrier and sterically stabilize the polymerized particles in a dispersed form. The fixed segment (B} is composed of (1) a compound that easily associates with the acrylic monomer to be polymerized, such as methyl acrylate,
Methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-
esters of acrylic and methacrylic acids, such as ethylhexyl acrylate, octyl methacrylate, etc.; For example, it may consist of a copolymer of glycidyl-containing acrylates and methacrylates, such as glycidyl acrylate and glycidyl methacrylate.

This copolymer is further reacted with a polymerizable ethylenically unsaturated acid, such as acrylic acid or methacrylic acid. Preferred polymer segment [B}' is methyl methacrylate,
It is a terpolymer of glycidyl methacrylate and methacrylic acid.

The methacrylate and legs are usually connected entities, and the segment is attached to the primary mirror of the graft copolymer;
Segment [Immediately in the primary mirror or on the main chain]

Preferably, the stabilizer-containing monomer solution contains from about 1 to about 25 weight percent stabilizer. Polymerization can be carried out in a conventional manner using heat and/or catalysts and various solvents and techniques.

Generally, free radical catalysts such as cumene hydroperoxide, penzoyl peroxide, or similar peroxygen compounds, or azo compounds such as azobis(isobutyronitrile) are used. The resulting non-aqueous acrylic dispersion must contain at least about 0.5% by weight, based on polymer mass, of dispersed microgels.

This Miku. The gel particles have a refractive index substantially the same as the polymerized ethylenically unsaturated monomer and have a particle size of about 1-40. The microgel particles are essentially insoluble in tetrahydrofuran and are substantially crosslinked. at least 0
．． It should be noted that the presence of 5% by weight of microgels is important to the invention. Miku. The presence of gel particles provides unique improvements over conventional solutions used as topcoats in that the build-up (film thickness), gloss, film deposition efficiency, and pattern control with metallic pigments are substantially improved. . The composition may also include other ingredients such as crosslinkers, coalescing agents, catalysts, plasticizers, fillers, pigments, etc. The present invention is particularly useful for depositing films containing metal pigments such as aluminum, nickel, and stainless steel because of the excellent pattern control of the resulting films. An active solvent for the acrylic non-aqueous dispersion polymer is added prior to adding the aminoplast resin to the composition. Examples of active solvents are aromatic hydrocarbons or oxygen-containing solvents, such as esters, ketones, ether alcohols,
and halogenated hydrocarbons. Examples of this active solvent are ethoxycetyl acetate (cellosolve acetate),
2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, acetone, toluene, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl isoamyl ketone, diethyl ether, amine acetate, butyl acetate, ethylene glycol diacetate,
These include cyclohexanone, trichlorotrifluoroethane, trichloromonofluoromethane, and 2-nitropropane. The addition of an active solvent renders the dispersion essentially solvent-based. While most of the acrylic polymer is essentially solvated, the microgel particles do not go into solution. The ratio of active solvent to dispersion liquid or non-active solvent is from 35 to 65 to about 9%.
It should be. The polymer solution is then mixed with aminoblast resin and the polymer is heat cured.

The Aminiblast resin used as a crosslinking agent for this polymer dispersion is an aldehyde condensation product of melamine, urea, and acetoguanamine. These can be water-soluble or soluble in organic solvents. Generally, the aldehyde used is formaldehyde, but useful products can also be made from other aldehydes such as acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural, and the like. Melamine or urea condensation products are most common and preferred. Amine-aldehyde condensation products are made by methods well known in the art using acidic or basic catalysts and various conditions of time and temperature.

The aldehyde is finally used as a solution in water or alcohol, and the condensation, polymerization and etherification reactions can be carried out sequentially or simultaneously. The aminoplast resin should constitute from about 5 to about 5 percent by weight of the composition.

The aminoblast can be simply added to the composition, or can be added at elevated temperatures, such as 40 qo or higher, if desired. The above compositions are very useful as coatings on substrates.

Simply apply the composition to the substrate and apply 65.6 to 1770 (150
-3500 F) for about 5 to about 60 minutes to cure the coating on the substrate. The coating can be applied by conventional methods such as dawn coating, immersion coating, and roll coating. A particularly preferred method for compositions containing metal pigments is fog coating. This is because compositions containing microgel particles can be applied with good efficiency, high buildup, and pattern control of metallic pigments. Any substrate such as paper, metal, wood, paperboard, plastic can be coated with the composition.

Preferred substrates are metals or primed metals such as those found in automobile bodies. The following examples illustrate specific embodiments of the invention.

However, the invention is not limited to this embodiment, as it is susceptible to many variations. All parts and percentages are by weight unless otherwise indicated. Example 1 A flask was charged with 440 g of an aliphatic hydrocarbon mixture of hexane and hebutane, 195 g of VM&P naphtha, 32 g of methyl methacrylate, 93.2 g of ethyl acrylate, 8 g of 2-oxyethyl methacrylate, and 4 g of methacrylic acid. .8 hours, azopisisobutyronitrile 2.8 hours, and dispersion stabilizer 4 hours
6 Prepare the evening meal.

The above dispersion stabilizer is 55% butyl acetate and 20% ethyl acetate.
, 44% methyl methacrylate, 4.9% glycidyl methacrylate, 90.3% poly-12-oxystearic acid and 9.9% glycidyl methacrylate in a solvent solution consisting of 4.5% toluene, 20.5% VM&P naphtha. 7% reaction product 50.4%, 36.4% of methacrylic acid 0.7%
% solid solution. The charge was heated to reflux at 84 qo, and after 20 minutes, 128 q of methyl methacrylate, 3968 q of ethyl acrylate, 32 q of 2-oxyethyl acrylate, 19.2 q of methacrylic acid, 11.2 q of azobisisoputilonitrile A mixture consisting of the above-mentioned dispersion stabilizer 196 was added dropwise over a period of 3 hours. Continue refluxing for another 3 hours,
Cool the mixture and stir. The above thermosetting acrylic polymer dispersion 17, melamine-formaldehyde resin [
CMmel 301] 1.5 evening, toluene 1.
Add 5 drops, 0.1 drop of butanol, and 6 drops of a commercial mixture of mono- and dibutyl phosphate esters.

The resulting composition was found to contain approximately 6% by weight microgel particles on a non-volatile basis. The above composition was mixed with a 90/1 Tsuboo mixture of xylene and butanol to treat the lungs. Diluted to a sand viscosity of 3 as measured in a 4-food cup and further diluted to 25% with a 1:1 xylene and Solvesso 10G aromatic solution.
Dilute until the capacity decreases and No. The viscosity was measured with a 4-force cup at 10,000 seconds and was sprayed onto a steel substrate to give a 12100 (2
500F) for 30 minutes, producing a film with excellent gloss and flexibility.

Example 2 Hebutane 386.5 ml, hexane 386.5 ml in flask
After 64.8 hours of methyl methacrylate, 4.6 hours of azobisisobutyronitrile, and 18.0 hours of dispersion stabilizer,
Heat to reflux at 770°C.

This dispersion stabilizer is a reaction product of 44% methyl methacrylate, 4.9% glycidyl methacrylate, 90.3% poly-12-oxystearic acid and 9.7% glycidyl methacrylate, and 0 methacrylic acid. .7% of 36.
Consisting of a 4% solids solution. After heating for 20 minutes, add 2-
Oxyethyl acrylate 146%, methacrylic acid 37%
．． 5 days, styrene 4 times, butyl methacrylate 285 times, methyl methacrylate 193.2 times, 2-ethylhexyl acrylate 292 times, octyl mercaptan 4.5 times.
10 times azobisisobutyronitrile, 11 times 2-oxyethyl ethyleneimine, and 423 times the dispersion stabilizer mentioned above were added over 3 hours.

After an additional hour at 88.5q0, add 2 portions of azobisisobutyronitrile, and during the next 21/2 hours add 2 portions of azobisisobutyronitrile every 1/2 hour.

Cool the composition and add 150 parts of heptane and 150 parts of hexane. The dispersion has a solids content of 52.2% and an acid number of 6.06. Add 6 parts of the above solution, 4 parts of melamine formaldehyde resin and 2 parts of aluminum pigment. The thus formulated paint is applied to the metal substrate using an automatic spraying device. The properties of a membrane made by firing the coating described above are compared with those of a membrane made by the same method except that the microgel particles are removed by dilution and centrifugation to separate the microgel from the acrylic polymer.

The properties of the microgel-containing membranes are improved by polymerizing the same basic monomers without stabilizers in an active solvent and with the same amount of aminofol. Compare with a film made by adding rust and aluminum pigment. A solvent solution of 9 parts of xylene and 11 parts of butanol was added to all the above compositions to obtain No. 4 Measured with a food cup to obtain a viscosity of 3 inkstone sand, and further diluted 1:1 xylene with Solbeso 100 until the volume was reduced by 25%. 4Measure with a food cup, set the viscosity to 10,000 seconds, expose the coating,
Cure at 2100°C (250oF) for 30 minutes.

The results are shown in Table 1 below. Table 1 It can be seen that the pus accumulation, gloss, and texture of the microgel-containing composition are superior to those of the conventionally prepared composition and the same composition without the microgel.

The pattern control and gloss reading of the microgel-containing solution was obtained by forming and mixing the melamine-formaldehyde with 6 seals 40, adding 2% aluminum pigment, and diluting with aliphatic hydrocarbon (non-solvent) to a mist viscosity. compared with the dispersion of the coalesce.

This composition contains 22% active solvent and 78% inactive solvent. The pattern control of this dispersion coating is poorer than the solution coating described above, with a 20o gloss of only 69 for the dispersion coating. The present invention also includes improvements to thermoset acrylic enamels that are particularly useful as automotive coatings. This improvement consists of superior solvent blistering resistance, the ability to apply a satisfactory coating in two coats instead of three, high gloss, and pattern control of the metal flake pigment, resulting in an aesthetic appearance of the coating. This improvement is mainly related to the modification of the paint binder by imines and the presence of a small proportion of insoluble polymer particles called microgels. By first dispersion polymerizing the monomers and then macerating this dispersion with an active solvent to form a solution, oxyalkyl acrylates exhibit excellent solvent blistering resistance and excellent pattern control when loaded with metallic pigments. Alternatively, it has been discovered that it is possible to produce a non-aqueous solution of a thermosetting acrylic polymer consisting of an oxyalkyl methacrylate, a dispersion stabilizer, a dispersion liquid, and a reaction product of an imine and a carboxylic acid.

This embodiment is an improvement on the above theme in that the addition of imine and carboxylic acid to the resulting polymer unexpectedly increases solvent blistering resistance.

In general, the method for producing non-aqueous materials of acrylic polymers in organic solvents is that the acrylic monomers are dissolved in the organic liquid, the resulting polymer particles do not fall off, and the acrylic monomers form dispersed polymer particles. It depends on the method of dispersion polymerization.

In the molecule, (i) a component that associates with the dispersed polymer particles;
(ii) carrying out the above reaction in the presence of a stabilizer having a component having a bulging chain structure which is solvated by an organic liquid and provides a stabilizing shield in place of the polymer particles;

The polymerized acrylic monomer is a hydroxyl group-containing compound of about 4 to about 3
% by weight, an example of which is described above.

The hydroxyl-containing acrylic monomer and other copolymerizable monomers can be copolymerized to form a polymer dispersion, as long as the final polymer contains at least about 4% by weight of the hydroxyl-containing monomer. . Examples of other monomers that can be copolymerized with this hydroxyl group-containing monomer are carboxyl esters such as butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, and the like. Other copolymerizable monomers, such as styrene,
Methyl methacrylate, methyl acrylate, post-acrylic ethyl, etc. can also be used. The inclusion of ethylenically unsaturated carboxylic acids and imines in the polymerized monomers provides solvent blistering resistance and increases pattern control of the coating composition.

Therefore, the monomer to be polymerized according to this improvement needs to contain at least one kind of ethylenically unsaturated carboxylic acid.
The polymerizable ethylenically unsaturated carboxylic acid can be an acidic acrylic compound, such as acrylic acid, methacrylic acid. The imine can be an imine-containing compound that reacts with the carboxylic acid described above.

2-oxyethyl ethylene imine is used as the imine because of its availability and because it has been found to be most effective.

The imine can be reacted with the above acid during or after the polymerization process.

In some cases, it may be preferable to carry out the reaction with imine simultaneously with the copolymerization reaction. In this embodiment, the imine is added to the polymerization mixture at any point prior to completion of the polymerization reaction. The mixture of monomer, acid, imine, and dispersion stabilizer is
Generally about 70 to about 9% monomer by weight, about 0 carboxylic acid
．． It should contain from about 5% to about 5% by weight, from about 0.5% to about 5% imine, and from about 1% to about 25% dispersion stabilizer.

The ethylenically unsaturated monomer is polymerized in a dispersion liquid (non-solvent) that solubilizes the monomer but does not melt the resulting polymer and forms dispersed polymer particles. The nature and amount of the non-solvent is as described above for the basic dispersion. The dispersion stabilizer used in this modification is the same as described above. Other factors relevant to modification and mentioned above with respect to the base dispersion include the amount of microgel in the coating composition, the presence of other ingredients such as plasticizers, fillers, pigments, and the presence of active solvents for the acrylic non-aqueous dispersion polymer. including adding, mixing the polymer solution with the aminoplast resin, and using the composition to coat the substrate.

Example 3 The thermosetting acrylic polymer dispersion of Example 2 (solid 52.
2%, acid number 6.06) and 61.36 parts of melamine-formaldehyde resin were added with pigment paste and mixed with a mixture of active and inactive solvents. The viscosity of No. 4 was adjusted using the same solvent mixture. The above dispersion is formed into a coating by adjusting the viscosity with a four-fod cup.

This composition was sprayed onto an aluminum substrate and 12100 (
Bake at 250° F. for 30 minutes and test the coating for solvent blistering resistance. Solvent blisters, which are caused by evaporation of the solvent in the coating film during firing and cause pores and/or bubbles on the coating surface after curing, were visually inspected. The membrane made with the composition of the present invention is membrane 6.4
It was found to contain 0 to 1 blisters per lin2. This was compared to two coatings formed using the same method but without the addition of imine to the polymerizable composition. The solvent blistering resistance of these coatings was tested and a film of 6.45 (
It was found to contain 10 to 15 blisters per type (1 type).
Comparison of the above coating film with a coating film made using the above composition containing 2.3% methacrylic acid, no imine, and 1/2% each of triethylamine and dimethyldodecylamine, which are ordinary solvent anti-blister agents. did. The number of solvent blisters per 1i# of 6.45 for this coating is 13-15 and 4-1, respectively.
It is 6.

Therefore, the improved method does not add imine and therefore provides superior solvent blister resistance over the same film formed using a conventional solvent blister resistance agent.

Example 4 Methyl methacrylate 16.3 days, styrene 27.3 days,
Butyl methacrylate 17.7 days, 2-ethylhexyl acrylate 28.2 days, 2-oxyethyl acrylate 9.1 days, methacrylic acid 1.6 days, 2-ocynethylethyleneimine 0.7 days, octyl mercaptan 0.12
A non-hydrothermally curable acrylic polymer dispersion is then made by heating dispersion stabilizer 9.1 in a 5:50 solids solvent in which the solvent system is that described in Example 3.

The above dispersion stabilizer is 55% butyl acetate and 20% ethyl acetate.
, 44% methyl methacrylate, 4.9% glycidyl methacrylate, 90.3% poly-12-oxystearic acid and 9.9% glycidyl methacrylate in a solvent solution consisting of 4.5% toluene, 20.5% VM&P naphtha. Reaction product with 7% 50.4 36.4% of methacrylic acid 0.7%
Consists of a solid solution. The above composition is heated under reflux until the acid value reaches 670 and the viscosity becomes 340 ps. Add melamine-formaldehyde to the resulting dispersion, and add the melamine-formaldehyde to the vessel. The coating was reduced to a viscosity of 10,000 sand as measured in a four-feed cup, coated on an aluminum substrate, and baked at 12 rC (250o F) for 30 minutes.
It was found that 3 bulges were included. The above is compared to a coating made in the same manner from the same composition but using 2.3 liters of methacrylic acid and no imine.

The resulting membrane has approximately 15 bulges per 6.45 membranes (type 1). In another embodiment of the present invention, when non-shedding microgel particles are added to a hydroxyl-containing polymerized ethylenically unsaturated monomer solution, the composition can be atomized with high film build-up in two coats with increased coating efficiency. The resulting film was found to have significantly improved pattern control and blistering resistance and improved gloss. This thermosetting acrylic polymer solution is formed by polymerizing acrylic monomers in a solvent. The acrylic monomers that are polymerized contain from about 4 to about 3 weight percent of hydroxyl-containing compounds. Examples of hydroxyl-containing monomers include: o Hydroxyl-containing acrylic monomers may be copolymerized with other copolymerizable monomers as long as the final polymer contains at least about 4% by weight of hydroxyl-containing monomers. can.

Examples of this copolymerizable monomer are mentioned above. Preferably, the monomer system contains from about 0.5 to about 15 weight percent ethylenically unsaturated carboxylic acid. The ethylenically unsaturated monomer is polymerized in an active solvent for the polymer.

Examples of active solvents that can be used are aromatic or oxygen-containing solvents and halogenated hydrocarbons, such as esters, ketones, ethers, ether alcohols, ethoxyethyl acetate (cellosolve acetate), 2,2,4-trimethyl-1,3- Bentanediolmo/isobutyrate, acetone, toluene, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl isoamyl ketone, diethyl ether, amine acetate, butyl acetate, ethylene glycol diacetate, cyclohexanone, trichlorotrifluorethane, trichloromonofluoromethane, 2 Nitropropane, etc. The polymer solution can generally contain any amount of solids, but
Preferably, the solution has a solids content of about 40% to about 60%. By adding microgel particles to the above solution, either alone or in a mixture with another polymer, such as in dispersed form,
Unexpectedly excellent gloss, pattern control and film build-up are achieved.

The microgel particles have a refractive index substantially the same as the polymerized ethylenically unsaturated monomer and have a particle size of about 1 French to about 40 French. The microgel particles are essentially insoluble in aromatic hydrocarbons, ketones, esters, or alcohols, or even tetrahydrofuran, and are substantially crosslinked. It should be noted that the presence of at least 0.5% by weight of microgels is important according to the invention. The presence of microgel particles provides unique improvements over conventional solutions used as topcoats in that film build-up (film thickness), gloss, coating deposition efficiency, and pattern control with metallic pigments are substantially improved. I understood. Microgel particles are produced by polymerizing a hydroxyl group-containing ethylenically unsaturated monomer in the presence of a polyfunctional dispersion stabilizer in a dispersion liquid that is a solvent for the monomer but a non-solvent for the resulting polymer.

Examples of hydroxyl group-containing monomers that can be polymerized in this operation are the same as those used in the polymer solution.

All as described above, the monomers are polymerized in a dispersion liquid that solubilizes the monomers but leaves the resulting polymer essentially insoluble, forming dispersed polymer particles. The resulting dispersed polymer contains microgel particles, which can be separated from the bulk of the polymer by diluting with an active solvent, centrifuging, separating the transparent top layer, and washing the microgel.

Microgel particles can also be obtained by passing the dispersed polymer through a molten glass transfer vessel and washing it with tetrahydrofuran.

Microgel particles can be simply added to thermosetting compositions without the need for elaborate conditions.

In a preferred embodiment, the microgel particles are added to the polymer solution by simply mixing the non-aqueous dispersion forming the microgel particles with the polymer solution. The above composition includes a crosslinking agent,
Other components such as binders, catalysts, plasticizers, fillers, pigments, etc. may also be included. This embodiment is particularly useful for depositing films containing metal flake pigments such as aluminum, nickel, stainless steel, etc. because of the excellent pattern control of the resulting coating. The acrylic thermoset enamel polymer solution containing the added microgel particles is then mixed with the aminoplast resin and crosslinked by firing when the resulting mixture is applied as a coating.

The aminoplast resin used as a crosslinking agent for this polymer dispersion is an aldehyde condensation product of melamine, urea, and acetoguanamine. Examples of suitable aminoplast resins and methods of making them are described above with respect to other embodiments of the invention. The aminoplast resin should constitute from about 5 to about 5 percent by weight of the composition. Aminoplast can simply be added to the composition,
Alternatively, it can be added at elevated temperatures, such as 40°C or higher, if desired. This composition is very useful as a coating for substrates.

Simply apply this composition to the substrate and
The coating is cured on the substrate by heating at 50 to 350 degrees Fahrenheit for about 5 to about 60 minutes. The coating can be applied by conventional methods such as spray coating, dip coating, and roll coating. A preferred method is coating. This is because compositions containing microgel particles can be applied with good deposition efficiency and rapid film accumulation. Any substrate such as paper, metal, wood, paperboard, plastic, etc. can be coated with the present composition.

Preferred substrates are metals or primed metals such as those found in automobile bodies. Example 5 Hebutane 386.5 ml, hexane 386.5 ml in flask
After 64.8 hours of methyl methacrylate, 4.6 hours of azobisisobutyronitrile, and 18.0 hours of dispersion stabilizer,
Heat to reflux at 77q0.

This dispersion stabilizer is a reaction product of 44% methyl methacrylate, 4.9% glycidyl methacrylate, 90.3% poly-12-oxystearic acid and 9.7% glycidyl methacrylate, and 0 methacrylic acid. .7% of 36.
Consisting of a 4% solids solution. After heating for 20 minutes, put 2 into the flask.
- Oxyethyl acrylate 146, methacrylic acid 3
7.5 night, styrene 438 night, butyl methacrylate 28
5 nights, 'Methyl methacrylate 193.2 nights, 2-ethylhexyl acrylate 292 nights, octyl mercaptan 4.5 nights, azopisisobutyronitrile 10 nights, 2-oxyethyl ethyleneimine 11 nights, the above dispersion stabilized. agent 42
Add 3 evenings in 3 hours. After an additional hour at 885° C., add 2 portions of azobisisobutyronitrile, then add 2 portions of azobisisobutyronitrile every 1 hour for the next 21/2 hours. Cool the composition and add 150 g of heptane and 1 g of hexane.
Add 50 evenings. To this dispersed polymer are added 174.4 parts of Cellosol acetate, 101.6 parts of VM&P naphtha, 101.6 parts of Solven 150 aromatic ring solvent, 68.8 parts of isopropyl alcohol, and 133.6 parts of butanol. .
The above thermosetting acrylic polymer dispersion 112%, butylated melamine formaldehyde resin 6.7%, acetone 50%, cellosolve acetate 30%, toluene 12%
6.3% of a solvent mixture consisting of 8% of Solveso 150 is added.

The product mixture was centrifuged and filtered and was found to contain approximately 1% by weight of microgel particles on a total non-volatile basis. 6 parts of the microgel removed from the above dispersion was dissolved in 90% xylene.
and 10% 2-oxyethyl acrylate, 2.5% methacrylic acid, 30% styrene, 2-
6 parts of a thermosetting acrylic polymer solution consisting of a 50% solution of a polymer consisting of 20% ethylhexyl acrylate, 19.5% butyl methacrylate, 18% methyl methacrylate, 4 parts melamine formaldehyde resin, and aluminum pigment. Add to 2nd part.

The above composition was mixed with solvent thinner in No. The viscosity was determined to be 3 Cape sand by measuring in a 4-food cup, and the volume was reduced by 25% with a 1:1 xylene-Solveso 10 aromatic solvent thinner to obtain No. Thin to the consistency of LA sand as measured in a 4-food cup, spread on the panel, flash for 2 minutes at room temperature, apply another coating at this point, flash for 5 minutes at room temperature, then 12loo (2500F) Leave to harden for 30 minutes.

Miku this membrane.

Compare with the same composition coated in the same manner without the addition of gel. The film accumulation of the film coated with the addition of microgel was 0.
05 ribs (1.96 mm), but the membrane accumulation of the membrane without microgel is only 0.045 ribs (1.76 mm).
It is.

Additionally, the 20o gloss meter reading for the microgel-containing film is 71%, while the gloss for the film without microgel is only 67%. The pattern control of the microgel-containing film is comparable to that of the film that does not contain microgel. Example
6 The non-hydrothermally curable acrylic dispersion polymer 4 anchors described in Example 5 were mixed with 10% 2-oxyethyl acrylate and methacrylic acid in 90% xylene and 10% butanol without centrifugation and microgel separation. 1.8%, 2-oxyethylethyleneimine 0.7%, styrene 30%, 2-ethylhexyl acrylate 20%, azobisisobutyronitrile 0.06%, butyl methacrylate 19.5%,
Two parts of a thermosetting acrylic polymer solution consisting of a 50% solution of a polymer consisting of 18% methyl methacrylate, four parts of butylated melamine formaldehyde resin, and two parts of aluminum pigment are added.

Example 5 The above composition was diluted to a mist viscosity with a solvent thinner.
Apply as described in .

This membrane is compared to the same composition coated in the same manner without the addition of dispersed polymer. The film coated with the dispersion polymer has a film build-up of 0.05 mils (1.96 mils), while the film without the dispersion polymer has a film build-up of 0.045 (1.7 mils).
6 mil).

Furthermore, the 20o gloss meter reading of the film modified with the dispersion polymer was 7.
3%, but the gloss of the film without added dispersion polymer is 65
It is only %. The pattern control of the film containing the dispersed polymer is good, but in comparison, the film without the addition of the dispersed polymer is inferior. Example 7 The non-hydrothermally curable acrylic dispersion polymer 3 anchor portion described in Example 5 was subjected to centrifugation and microgel separation without centrifugation and microgel separation.
10% 2-oxyethyl acrylate, 1.8% methacrylic acid, 0.7% 2-oxyethyl thylenimine, 30% styrene in 90% xylene and 10% butanol,
2-ethylhexyl acrylate 20%, azobisisobutyronitrile 0.06%, butyl methacrylate 19.
5% of a polymer consisting of 5% and 10% methyl methacrylate.
3 parts of a thermoset acrylic polymer solution consisting of a 10% solution is added to 4 parts of butylated melamine formaldehyde resin and 2 parts of aluminum pigment.

The above composition is brought to a mist consistency with a solvent thinner and applied as described in Example 5.

This membrane is compared to the same composition coated in the same manner without the addition of dispersed polymer.

The film build-up of the film coated with the addition of the dispersion polymer was 0.048 (1.96 mil), but the film build-up of the film without the addition of the dispersion polymer was only on the 0.045 side (1.76 mil). do not have. Furthermore, the film modified with the dispersion polymer had a 200 gloss meter reading of 73.
%, but the gloss of the film without the addition of dispersed polymer is 65%.
It's nothing more than that. The pattern control of the film containing the dispersed polymer is good, but in comparison, the film without the addition of the dispersed polymer is inferior. Example 8 The non-hydrothermally curable acrylic dispersion polymer 2 described in Example 5 was added without centrifugation and microgel separation with 10% 2-oxyethyl acrylate in 90% xylene and 10% butanol; Methacrylic acid, 1.8%, 2
-Oxyethylethyleneimine 0.7%, styrene 30
%, 2-ethylhexyl acrylate 20%, butyl methacrylate 19.5%, azobisisobutyronitrile 0
．． Add 4 parts of a thermosetting acrylic polymer solution consisting of a 50% solution of a polymer consisting of 0.6% methyl methacrylate and 18% methyl methacrylate, 4 parts of butylated melamine formaldehyde resin, and 2 parts of aluminum pigment.

Example 5 The above composition was diluted to a mist viscosity with a solvent thinner.
Apply as described in .

This membrane is compared to the same composition coated in the same manner without the addition of dispersed polymer.

Claims (1)

Claims: 1(a) (1) at least 4% by weight of hydroxyalkyl esters of methacrylic acid and/or hydroxyalkyl esters of acrylic acid; and (2) (i) methacrylic acid and/or acrylic acid;
at least one polymer that is a copolymerization product of an ethylenically unsaturated monomer mixture comprising (ii) an alkyl ester of methacrylic acid and/or an alkyl ester of acrylic acid; and (iii) optionally styrene. (b) a solvent for said polymer; (c) at least 5% by weight, based on the weight of polymer solids in the composition, of microgel particles comprising: (1) ethylenically unsaturated; an addition copolymer of a monomer and a dispersion stabilizer, said dispersion stabilizer being a branched copolymer containing dipolymer segments, (i) the first segment of which is an aliphatic hydrocarbon; solvated by
and (ii) the second segment is a reaction product of glycidyl acrylate or glycidyl methacrylate and poly-(12-hydroxystearic acid);
This second segment is a polymer of different polarity than the segment and is relatively poorly solvated by aliphatic hydrocarbons, and this second segment is an alkyl ester of acrylic acid or an alkyl ester of methacrylic acid, glycidyl acrylate or (2) the microgel particles are insoluble in the solvent, (3) have a particle size of 1 to 40 microns, and (d) melamine, urea or A non-aqueous coating composition comprising an aminoplast resin, which is an aldehyde condensation product of acetoguanamine. 2(a) at least 4% by weight of (1) a hydroxyalkyl ester of methacrylic acid and/or a hydroxyalkyl ester of acrylic acid; and (2) of (i) methacrylic acid and/or acrylic acid; (ii) methacrylic acid; alkyl esters and/or alkyl esters of acrylic acid, and (iii) 2-oxyethylethyleneimine, and (iv
) at least one polymer which is a copolymerization product of a mixture of ethylenically unsaturated monomers, optionally including styrene; (b) a solvent for said polymer; (c) the amount of polymer solids in the composition. at least 5% by weight of microgel particles, the microgel particles being an addition copolymerization product of (1) an ethylenically unsaturated monomer and a dispersion stabilizer; is a branched copolymer containing dipolymer segments, (i)
the first segment is solvated by an aliphatic hydrocarbon and is the reaction product of glycidyl acrylate or glycidyl methacrylate with poly-(12-hydroxystearic acid); and (ii) the second segment is The second segment is a polymer of different polarity than the first segment and is relatively non-solvable with aliphatic hydrocarbons, and this second segment is an alkyl ester of acrylic acid or an alkyl ester of methacrylic acid, an alkyl ester of acrylic acid, a polymer of glycidyl or glycidyl methacrylate and acrylic acid or methacrylic acid, (2) the microgel particles are insoluble in the solvent, (3) having particles from 1 to 40 microns, and (d) melamine, A non-aqueous coating composition comprising an aminoplast resin which is an aldehyde condensation product of urea or acetoguanamine.