DE2453378A1 - HEAT-RESISTANT MASS - Google Patents

Description

DR. MÜLLER-BORE DIPL.-ING. GROENING

DIPL.-CHEM. DR. DEUFEL · DIFL, .- CHEM. DR. SCHÖN

DIPL.-PHYS. HERTEL

PATENT LAWYERS

S / R 14-97

Rohm and Haas Gorapany, Philadelphia, Pa. / UNITED STATES Thermosetting mass

"The invention relates to the decoration of metals as well as thermosetting Coating compounds that are applied to the surfaces to be coated from aqueous media. Under the term "Metal decoration" is to be understood as the coating of a metal sheet with a suitable coating compound, after which the sheet metal is subjected to various mechanical deformation processes. Examples of decorated metallic objects that are used in the usual way are beer cans, beverage cans, G-era jars, containers with screw caps and Aerosol container. The coatings for such items must undergo a number of treatments carried out during manufacture withstand without cracking or peeling of the coating. These treatment measures carried out during manufacture vary from very mild treatments (for example the formation of can bodies) to extremely strong

809830/0931

Effective "measures (for example the production of aerosol container domes)" The compounds can also be applied to previously formed objects _9, for example, can bodies, tooth oast tubes, etc. formed using a mandrel and made up of two pieces.

In performing a typical process for making a finished metal-decorated article, a Oilmented white base coating mass on a metallic one The substrate is rolled on and then the coated substrate is baked will. Then a decoration print is applied to the white G-round cover »While the printing ink is still wet istj a clear varnish is rolled onto the printing in order to to protect the printing ink »The coated metal sheet is then fired« to adjust its final hardness »The finished coated metal sheets can then be stacked for various periods of time prior to processing into a final product and be stored »It is essential, that the coating has a has good resistance to stacking when hot this prevents the metal sheets from sticking to one another, since this will damage the coatings «, The coated sheets are then processed into different shapes according to the end use of the sheet material. For example, it is crucial whether the tin is suitable for cans, Lids, screw caps etc »is processed» Das Materia ,! not only has to withstand the various conditions encountered when processing the sheet metal, but in many cases also be resistant to the sterilization conditions which are required in many cases and exposure to high temperatures. In such cases the paint coating must have good overheating properties.

£ 09830/0989

To achieve optimal hot stack properties of coatings it is advisable to use a thermosetting coating compound, which are networked to a high degree during curing. The cured coating must, however, also be flexible enough that it can withstand the treatments that occur during the manufacturing process. Becomes a "coated" sheet then subjected to severe "conditions during processing a "soft" thermosetting resin should be used, i.e. a resin that is thermoset with an aminoplast which has a low crosslink density. In contrast, the coated sheet metal is subject to relatively mild conditions exposed during processing, a "hard" thermosetting resin can be used.

So far have been in the implementation of metal decorations Base coats are used that are made up of certain anti-corrosive pigments based in non-aqueous binders of drying oils such as flaxseed oil, quick-drying ones Paints that contain natural resins or mixtures of natural and synthetic resins, furthermore alkyd materials were used, which with urea, Melamine or phenol / formaldehyde resins are modified. Such coating compositions are usually in high boiling Solvents brought on the market, which ensure good flow and leveling of thin films that are rolled on will. The solvents are often non-flammable, often of the types that emit toxic fumes during of coating. Solvent recovery systems are commonly used to address fire and health hazards used, the use of which also combats air pollution caused by the release of organic solvents in the atmosphere is conditioned.

It. there has long been a need for thermosetting coating

50983 0/0989

-A-

masses that can be applied from an aqueous medium, air pollution, fire hazards and others To prevent problems associated with the use of excess organic solvents, "Heretofore known aqueous coating systems such as those described in U.S. Patents 2,760,886; 2,918,391 and 3,033,811 However, for coating metals that the invention Purposes are to be supplied by directly working rolling devices as unsatisfactory, as they tend to dry on the rollers, causing difficulty in cleaning or blistering when wet Products are placed directly in an oven. Furthermore, the known aqueous coating systems are not suitable for post-deformation measures due to their brittleness or not suitable for further handling due to their softness. The largest Difficulty occurring in the case of water-based systems lies in adjusting the rheological ones Properties that are suitable for direct rolling of the system. There is a need for a mass that can flow and flow Has gradient properties that it has when it passes through a direct application roller device is applied, forms a uniform and smooth surface that does not have any streaks having. The disadvantage of the aqueous emulsions with regard to the flow and leveling is in the relevant industry, which deals with the coating of metals, known (see Paint and Varnish Production, February 1964, Pages 28 to 33). The flow and leveling properties of pigmented all-round coatings are therefore very critical, as pigmentation noticeably increases the flow of aqueous Systems is degraded.

In DT-OS 22 111 69 a thermosetting aqueous coating mass described, which can be applied to metals by direct rolling methods and films with

509830/0989

good looks. This mass can subsequently be deformed v / ground and after firing gives clear or pigmented Coatings that have excellent resistance to water and detergents possess, adhere very well to a variety of substrates, are very glossy and are advantageously beneath Use of directly working rolling devices can be applied, whereby the rollers have an e-eringe durometer hardness of for example have about 12. There, but soft rubber rollers do not have good delivery characteristics, is it?; wake-up, a thermosetting resin coating is available that can be applied using a mandrel applicator or a direct application roller, wherein the rollers have a high durometer hardness of for example have about 20 to 50 without affecting the flow and leveling properties. The invention represents such a coating compound is available.

The coating compositions according to the invention consist of an alkaline one aqueous mixture with a binder that is essentially consists of the following components:

A) A water-soluble salt of a tertiary amine with a water-insoluble addition copolymer with a Molecular weight from about 20,000 to 200,000 from a mixture of copolymerizable monomers im essential from

1) an ester of a (G., - C .., -) - alcohol with a ^, ß-un <resaturation Carboxylic acid,

2) 1 to 4% by weight of an olefinically unsaturated one Carboxylic acid and

3) about 3 to 20 weight-wise at least one compound consisting of hydroxy (Cp-O ₄ ) -Alky! Esters of an acid of the formula

809830/0989

2> nl ^H OOH

where η is a ppxizp number with a value of 1 Ms 2, and (H ₁ -Op) -AIk ^ IeStern of re-methylolacrylic acid is selected,

.B) a water-soluble condensation product of urea or a tria? .. in with formaldehyde or a water-soluble Methanol or ethanol ethers thereof, where

C) the mass of 1 to 5 weight ^ of a polyethylene glycol or a polyethylene oxide as a water-soluble rheology modifier with a number average des Molecular weight from about 400 to 100,000, the percentage being based on the total weight of A) and B) (solid basis) refer to ^

and wherein the weight ratio of A to B, on a solids basis, fluctuates between 85 t 15 and 65 s35, _v the minimum filra formation temperature of the mass is not higher than about 25 ⁰ G and the solids content of the mass is between 30 and 80 wt.

Appropriately, B consists of the reaction product of a urea / formaldehyde adduct with methanol, the urea / formaldehyde / methanol molar ratio being between 1 / 1.75-3 / 2-3.5, or a melamine / formaldehyde adduct with methanol , the molar ratio melamine! formaldehyde! methanol fluctuating between 1 / 7-10 / 12-17, or mixtures thereof. In the copolymer A, component (1) is preferably an ester of acrylic acid and an alkanol having about 2 to 12 carbon atoms, component (P) is methacrylic acid and component (3) is at least one hydroxyethyl acrylate or methacrylate or hydroxypropyl acrylate or methacrylate.

$ 09830/0989

If the coated metal is to be subjected to severe treatments during processing, such as those that occur in the manufacture of aerosol containers or bottle caps, then the copolymer should be a "soft" copolymer. The Tg of the "soft" copolymers should be below 0 ⁰ C, and preferably below -15 ° C. For best results, the coating composition should contain a volatile base, wherein a tertiary amine is preferred, and should be a minimum of FiImbildungstemperatur not comprise more than about 15 ⁰ O. If the coated sheet is subjected to mild conditions during further processing, for example when processing into cans, then either a "soft" or a "hard" copolymer can be used. '.

The most preferred copolymer is a copolymer of ethyl acrylate, Hydroxypropyl methacrylate, methacrylic acid and methyl methacrylate.

One of the monomers that are used in a significant amount to manufacture of the addition copolymer is used is a flexibilizing or "soft" monomer that is produced by the following formula

H ₂ C = CC-OR ₁

can be represented, wherein R is H or alkyl having 1 to carbon atoms, and R _{1 is} a straight-chain or branched radical of a primary or secondary alkanol, alkoxyalkanol or alkylthiaalkanol, the alkanol having 2 to about 14 carbon atoms. Examples are EthyH, • methylpropyl, η-butyl, 2-ethylhexyl, heptyl, hexyl, octyl, propyl, 2-methylbutyl, 1-methylbutyl, butoxybutyl, 2-methyl

5 0 9830/0989

pentyl, methoxymethyl, ethoxyethyl, cyclohexyl, n-hexyl, isobutyl, eth.ylth.iaathy 1, methylthiaethyl, ethylthiapropyl, n-octyl, 6-methylnonyl, decyl, dodecyl or the like. When R and R _{1 are} alkyl, R ₁ should contain from about 6 to about carbon atoms. When R is H and R _{1 is} alkyl, then R _{1 should have} 2 to about 12 carbon atoms in order for a "soft" monomer to be obtained.

Important properties of the copolymer are its toughness and flexibility as well as its influence on the minimum film formation temperature (MFT) of the coating compound. The glass transition temperature or glass transition temperature (Tg) of the copolymer and consequently the selection of the monomers and their proportions depend on their influence on the ^m R. The "Tg" is a common criterion for polymer hardness and is described by Flory in "Principles of Polymer Chemistry" on pages 56 and 57 (1953), Cornell University Press. Even if a measurement of the Tg is preferred, it can can also be calculated as described by Fox in "Bull. Am ₀ Physics Soc." 1, 3, page 123 (1956). Examples of the Tg of homopolymers as well as the inherent Tg thereof that enable such calculations are as follows;

Homopolymer of Tg

n-octyl acrylate -80 ⁰ C.

n-decyl methacrylate -60 ⁰ C

2-lthylhexylacrylat -70 ⁰ C.

Octyl methacrylate -2O ⁰ C

n-tetradecyl methacrylate - 9 ° C

Me thy Iac ry la t 9 ° C

n-tetradecyl acrylate 20 ⁰ C

Methyl methacrylate 105 ^° C

Acrylic acid 106 ⁰ C

509830/0989

These or other monomers are mixed v / ground obtained 7m to the ^ ewünschte Tg of the copolymers. It is known that with an even number of carbon atoms in the alcohol content, the extent and type of branching noticeably affects the Tg. The straight-chain products result in the low Tg.

The inventive ^f Jberzugsmasse in a similar manner which is described in "Resin Review", Vol. 16, No. 2 (1966) has a maximum Mi ¹ T. The MPT is determined according to the method. It is not only influenced by the Tg of the addition copolymer, but also by the plasticizers or leveling agents used and the quantities in which these agents are used. At MPT values well above this maximum, it becomes difficult to produce a uniform coating film and the integrity of the film is lost if the metal is deformed.

In addition to the flexibilizing monomer, the other essential monomers are the "toughening" or "hard" monomers including unsaturated acidic monomers and hydroxyalkyl methacrylates. "The hardness or softness of the acidic and other functional monomers is not critical because of the small amounts used.

The copolymers used according to the invention should have a molecular weight from about 20,000 to 200,000, the values being within this range by averaging the viscosity can be determined. About the acidic copolymers. in the aqueous media for the inventions ° -emässen To solubilize purposes, they are neutralized with a tertiary amine such as 2- (dimethylamino) ethanol. the Copolymers can be made by a variety of methods. "Unless is wise, you can" polymerize the appropriate Monomers in solution or in aqueous media, where

509830/0989

in the latter case a stable latex or a stable dis-oersion obtained. Γη some cases it may be necessary to use a chain regulator, to adjust a molecular weight within the desired range. This is especially the case when is polymerized in an aqueous medium. examples for Fat regulators that can be used are long-chain alkyl mercaptans, for example tert-dodecyl mercaptans the "formula:

H ₃ COCGH ₃ ) ₂ CH ₂ O (OH ₃ ^ ₂ GH ₂ G (CH ₅ ) ₂ SH

Isopropanol, isobutane oil, long-chain alcohols such as laury alcohol, tert.-octyl alcohol, Eumol, CGI «, C ₂ Gl, or O" BrCl ~. The amount of chain regulator that can be used depends on the particular system as well as by the respective conditions, and can be from O to 2 _s in relation $ by weight of the monomers vary. in general, said use is from 0.1 to 1 fo Br omtri chlorine than to the widest possible range of molecular weight, if necessary, in the aqueous To generate media.

While any suitable dispersant or emulsifier can be used in forming the copolymer by emulsion copolymerization, it is still preferable to use a salt as a dispersant in the system obtained from a previously prepared batch so that the coating composition has an assumes substantially uniform character. the amount of such dispersant, which can be used for performing such a latex polymerization, can be from about 0.5 fo to 6, based on the weight of the monomers, typically vary. used water-soluble free radical initiators, such as example -

509830/0989

wise ammonium, shark or potassium persulphate, or redox systems, in which tert-butyl hydroperoxide together with a Reducing agents, such as, for example, isoascorbic acid, are used can be used.

The presence of certain water-miscible solvents in the finished special amine copolymer salt solution markedly improves the stability of aqueous solutions of the amine salts, thereby improving the gloss of the coatings obtained therefrom. Furthermore, it is possible to use a greater variety of comonomers for special purposes, as above The suitable solvents, hereinafter referred to as "cosolvents", are soluble in water, but not to such an extent that they remain essentially in the water phase and are appreciably precluded from entering the polymer micelles Cosolvents enter the polymer micelles to a considerable extent. As a result, they exhibit a noticeable thickening effect which does not occur when the solvent remains practically completely in the water phase. The cosolvent should be volatile so that it does not remove the I ¹ Hm or the coating on drying in the air and is practically completely removed before firing, so that blistering is avoided during firing. The volatility should not be so high that the flash point of the aqueous preparations is too low. Suitable cosolvents are 2-butoxyethanol, 2-ethylhexyl alcohol, tert-butane oil, n-butanol, isopropanol, isophorone, butoxyethyl acetate, butoxyethoxyethyl acetate, ethoxyethoxyethyl acetate and triethanolamine. If the polymer is prepared in other types of organic solvents, such as acetone, ethanol or 2-lthoxyethanol, which cannot serve as cosolvents, then the solvent used to prepare the polymer can be removed before the acidic polymer reacts with the amine to form the Salt is neutralized,

509830/0989

since these solvents usually have no particular advantage with regard to the finished aqueous copolymer salt preparation offers.

To the salt of the acidic copolymer ?! To form, the acidic copolymer is introduced into water, followed by the addition of the amine. The mixture can then be heated with stirring to a temperature of approximately 40 to 80 ^° C. for a period of approximately 15 minutes to 15 hours. A temperature of 50 to 75 ° C. is preferably maintained. In some cases, especially in the case of polymers of low molecular weight in finely divided form, the reaction with the amine does not require any heat and is practically spontaneous.

If the acidic copolymer has been prepared in an aqueous medium, then the amine can be added directly to the aqueous dispersion of the copolymer through dialysis. The copolymer preferably has a reduced particle size so that the reaction with the amine in the formation of the salt is facilitated. Are the copolymer is produced by a solution method, then it can from the solution prior to its introduction isolated in the water, "In general, however, the solvent was found _s that does not have to be removed before the introduction of the copolymer in the water. If the solvent used to carry out the polymerization is one of the mentioned cosolvents _9, then it improves the clarity and the stability (against mechanical action and storage under normal conditions) of the aqueous solution that is obtained with the amine when it is used in an appropriate amount, the gloss of the films or coatings obtained being improved.

509830/0989

The unsaturated carboxylic acid can be a simple mouocarboxylic acid but it can also be about a half-ester or about a hemiamide of an α, ß-unsaturated dicarboxylic acid or salts thereof with a volatile base, such as ammonia, or with a volatile water-soluble amine, such as dimethyl amine. Diinethvlätha-nolapiin, triethylamine, triethanolamine, morpholine, TT-methylmorpholine, pioolin or the like. Examples of copolymerizable, ethylenically une-esaturated monocarbon or polycarboxylic acids are sorbic acid, cinnamic acid, vinyl pyrogenic acid, a-chlorosorhic acid, p-yinylbenzoic acid acid, acrylic acid, methacrylic acid, Male ins M-nre, Elmar acid, Aconitic acid, atropic acid, crotonic acid and ttaconic acid or wischeu of it, with itaconic acid and the α, ß-unsaturated Monocarboxylic acids, especially methacrylic acid and acrylic acid, to be favoured. Other copolymerizable acidic monomers are the alkyl semiesters or partial esters of unsaturated ones Polycarboxylic acids, such as taconic acid, maleic acid or fumaric acid, or their partial amides. Preferred half-esters are the lower-alkyl (C-, to '"!,' i-esters, such as acidic Methylitaconate, acidic "^ utylitaconate, acidic methylfuinarate, acid butyl fumarate, acid methyl maleate and acid butyl maleate. Such partial esters and partial amides are regarded as "α, ß-unsaturated monocarboxylic acids". Under this "References" are to be understood as meaning "racks" and "amides". The hydroxy1-containing monomers can be hydroxyethyl, Hydroxypropyl or hydroxybutyl acrylate or methacrylate, etc. or be ethyl or ^ ethyl-n'-methylol acrylate.

Other ethylenically unsaturated copolymerizable monomers, which may be present are suitable in combinations with the above-mentioned flexibilizing monomers and toughening monomers, provided that they do not adversely affect the desired properties of the copolymer (for example in an undesirable manner

509830/0989

increase the total Tg). These can be expressed by the formula:

H ₀ C = CC-OR ₂

C.

reproduce, wherein R has the meaning given above. Rp is preferably alkyl and is methyl or alkyl of about 13 to about 20 carbon atoms when R is and is alkyl of 1 to about 5 carbon atoms or alkyl of about 15 to about 20 carbon atoms when R is methyl. From the above it can be seen that in the case of alkyl acrylates and alkyl methacrylates, the Tg first decreases with an increased chain length of the alkyl group, whereupon it increases again. This means that both hard and soft monomers appear in each monomer group. Examples of such hard monomers and other hard monomers are: viny aromatic compounds such as styrene and Viny toluene, vinyl chloride, vinyl acetate, nitriles such as acrylonitrile, methyl tetradecyl _$!? Pentadecyl methacrylate, methyl methacrylate, ethyl methacrylate, tert-butyl aylate, butyl methacrylate and pentadecyl methacrylate. For this purpose, the oo-solvent, namely tert-butane oil, can be used in an amount of about 5 to 10 ^ ₅ based on the total weight of the solution.

The amount of amine used can be approximately 1 to 6 equivalents of the amine per equivalent of the acid in the copolymer. Generally a minimum of 1 equivalent of amine is required. Usually a maximum of 2 or 3 equivalents is most suitable. A typical preparation can consist of 150 to Parts of water per 100 parts of the polymer, about 10 to 50 parts of the cosolvent per 100 parts of the polymer, and 1 to Compound equivalents of the amine based on the content of the acidic component in the copolymer.

509830/0989

The acidic copolymers include "certain units in certain quantity ratios, as has been mentioned above. The content of 1 to 4 1" of acid-containing moieties and 3-20 $ of hydroxy! Containing units contributes to solubilization by treatment with the dimethylaminoethanol at. After solubilization, the pH of the aqueous system containing the solubilized copolymer is generally between 8.5 and 9.5, and if an amount of amine is added that is insufficient to bring the pH to about 8.5 to increase, then the time period during which the preparation is lagerunpcsfähig relatively short. If an excess amount of amine added, the pH value is increased _T of the system to a value of more than 9.5, then the viscosity is for Systems too high, which have concentrations of pesticides most suitable for coating as well as for impregnation. Will be a relatively small amount of If acidic groups are provided in the copolymer together with a considerable proportion of hydroxyl-containing groups, then the conversion of the copolymers into water-soluble salt molecules or micelles with colloidal dimensions takes place without the occurrence of excessive viscosity.

The manufacture of water-soluble salts of tertiary amines with a water-insoluble addition copolymer is described, for example, in US Pat. No. 3,245,932.

The water-soluble and heat-convertible condensation products of urea or criazine (e.g. melamine) with formaldehyde and / or its derivatives, which are obtained by reaction with ethanol or methanol, according to one of the The following reaction schemes can be established: (1) Control the reaction conditions, so that the degree of polymerization is kept very low, up to the monomer stage, and (2) Introduction of hydrophilic groups into the molecules of the poly-

B09830 / 0989

kidney condensates. For example, they can be produced by careful control of the reaction conditions, as described by Schildknecht in "Polymer Processes", "Volume J, page ff. (T-nterscience" Press, 1956). "The production of another class of compounds which is according to the invention, such as, for example, from N ^ T'-bis-fWethoxymethyΌ-urea, is described in» Pull. Chem. Snc. Japan ", Volume XI , No. 3 Page ? ^ 9 (1936). According to an embodiment preferred ^{according to the invention, a mixture of a urea / E 1} ormaldehyde - .. Arjr] t with methanol and a melamine / Porranaldehyde adduct with methanol is used in the coating mass.

"The coating composition according to the invention preferably contains a material which is referred to as a" leveling agent "or" Colrisimgsriittel ". These materials contribute to the fusing of the" pilms during the drying process before firing and promote the "flow of the coating composition during the" Racing cycle. However, since they are volatile, they do not belong to the finished coating. They can be characterized by low water solubility and are PTite solvents for the uncured polymer blend, being less volatile than water so that they can remain in the polymer after the water has evaporated. Furthermore, they are in such a form volatile to a sufficient extent that they can be removed from the "film" before the end of the firing cycle, and furthermore they are not susceptible to hydrolysis in alkaline media, either at ambient or elevated temperatures. They also serve to reduce the surface tension of the aqueous system so that it can wet the metal substrate in a simpler manner. Typical examples are the leveling agents mentioned above, furthermore diacetone alcohol, dimethylformamide, alkyl ethers of ethylene glycol and propylene glycol, as well as tributyl phosphate. The leveling or coalescing agent is preferably in the coating

50 98 30/09 89

Mass in a window of 10 "to 20 O-weight- ^," based on the weight of the solids, before ·. The water soluble ^{T /} Ondensati onsnrodukt of urea or ^ riazinetrione with formaldehyde is usually ^c f- solids containing T, ösunir are ttel in isopropanol or an appropriate Voluroenmiscbunff fms Tsopronanol and ^ utanol extending 'supplied as 80. The wassprlösü before OO ■ polymer salt is preferably brought into ei ^ ^ he ischung of water and an ^lr erlaufmittel in would find]. The coating composition therefore normally contains a leveling agent, even if no additional cosolvent has been added.

The rheology modifiers which can be used to practice the invention are materials which are known per se. Polyethylene glycols are marketed under the "Eezeich- ^v nun.p ·" Oarbowax ". Their production is carried out by" Fordvce ϊτ »-". Τ. / Τη. Ohem. Soc ". described "^ and 61, pages 1905 19 ¹ O (1939). Preferably, a Polyäthylenp-lykol with a molecular weight of about Λ-00 I? used 0000. poly (ethylene oxide ^ is a poly ^ t ^ eT" the Such materials are sold under the trade name "Polyox". They can be produced, for example, by the processes described in FS-Pi? 3 ^ 5 AOQ,? 167 519, 3 251 784 and 3 444 102. Polyethylene oxide preferably has a film weight which does not exceed approximately 100,000. ends made according to these patents to obtain this molecular weight or lower molecular weights. Such depolymerized products are commercially available it can be added to the hardening resin emulsion during or after its preparation, furthermore it can

509830/0989

of the preparation at the time of mixing with the condensation product from Farnstoff or ^ riazin with formaldehyde etc. are added.

Both the "^ olyox" and the "Carbowax" products are essentially polyoxyethylene polymers with linear chains and terminal hydroxyl groups. The terminal groups can be varied else in the ^w that they contain Estergruppen, ÄthercTU "Dpen,"3poxyp-rm> pen or other groups. Whenever reference is made to """olyäth ^ len ^ lycole", the functionally equivalent linear polyethers with terminal groups other than hydroxyl groups should always be included. "Such terminal greens, with the exception of the hydroxyl groups, should have no more than about 2 carbon atoms.

In the case of products which have the molecular weights according to the invention the nature of the end groups on the linear chain has essentially no rheology-imparting effect Properties of the polymer. The "Carbowax" type polyethylene glycols v / earth produced in such a way that water or ethylene glycol and ethylene oxide are used as a starting point, whereupon polymerized in the presence of an alkaline catalyst will. The "Polyox" polyethylene glycols are made by polymerizing ethylene oxide using various catalysts, as well as in the absence of water or a starter, like ^ lykol, made. The latter products can have a molecular weight of several million, with relatively broad molecular weight distributions compared to the Polyäthylenp-lykolen with low molecular weights, the using a starter. The proceeds borrowed "polyethylene oxide materials that According to the invention are suitable, can by over-polymerizing the products with a molecular weight of a few million getting produced. As mentioned above, the

509830/0989

Polyethylene glycols produced with the use of a starter • will, in general, have a very narrow molecular weight distribution, R. These facts show that the molecular weight distribution of the polyether is not particularly critical. Wira a molecular weight given, this is to be understood as the number average molecular weight.

The exact mechanism by which the polyethylene glycols are used as well The poly (ethylene oxides) act to increase the rheological 'properties Modifying the coating compounds is not known. In the amounts used, they do not act as a thickener for the mass, but rather set the viscosity of the Masses down. It is believed that these compounds form complexes with the aminoplast, i.e. the urea or triazine / formaldehyde condensation product, able to form, with the normal rapid increase in viscosity decreasing, which with a relatively small increase in the solids content occurs in the compositions according to the invention in the absence of a rheology modifier can be done. A coating composition without a rheology modifier can cure very quickly, whereby Stripes are found in the finished coating, in contrast to the flow of coating compounds containing the rheology modifiers included, together to form a smooth coating before curing. In practicing the invention, a synergistic effect between the urea or triazine / "formaldehyde condensation product and the rheology modifier achieved while achieving improved pleating. This means that the improvement in pitting is noticeable is more pronounced than the additive effect of the condensation product as well as the rheology modifier. '

Because the mixture of the water-soluble salt, the water-insoluble Copolymers and the aminoplast during a period of storage should be stable, and since the aminoplast under acidic conditions

5 0 9 8 3 0/0 9 89

conditions is reactive, thus β the mixture can be made alkaline. A volatile base such as ammonia or a tertiary amine. is used to make the system alkaline, since tertiary amines do not react with the "formaldehyde which has bonded with the aminoplast. The tertiary amines also act as corrosion inhibitors when the sockets according to the invention are used to coat metal. The The tertiary amine must be volatile to such an extent that it is driven out of the film during firing. However, it must not be so volatile that it escapes or becomes pasted in a flash if the coating material is sprayed is applied. Triethylamiu is particularly preferred in terms of a good balance of properties, easy availability and economy. The pH of the mixture should be kept between 9 and 11 in order to achieve good storage stability. However, an initial pH adjustment alone is not sufficient to ensure sufficient stability and retention of the properties, since samples which have been neutralized with ammonia up to the desired pH range have inadequate stability on prolonged storage, although satisfactory films can be obtained when the ammonia-neutralized preparations are used shortly after manufacture. If, however, the tertiary amine is the predominant nitrogen base present, then small amounts of ammonia can be used without adverse effects. The amounts of amine used vary with the specific composition observed, but are between 1 and 5 parts by weight per 100 parts by weight of the Coating compound (solids basis) According to a preferred embodiment, 2 parts by weight per 100 parts by weight of the coating compound (solids basis) are used.

Although a dispersant can be used when pig-

509830/0989

However, due to the presence of the acidic components in the colloidal dispersion, a dispersant is not essential for dispersing pigments in a large number of dispersants in a satisfactory manner. The effect of the dispersant on the properties of the finished film must be "taken into account. Many dispersants" remain ^{unchanged in the "1} ^ iIm, so that in this way the water resistance of the" ^ film is considerably impaired. Other dispersants adversely affect the stabilities of the system to which they have been added.

According to a preferred embodiment, the ammonium and lower amine salts of polymeric carboxylic acids are used as dispersants. The ammonium and lower amine salts of polyacrylic acid and polymethacrylic acid and similar salts of the polymeric acid obtained by copolymerizing methyl vinyl ether with maleic anhydride are suitable. In a particularly preferred embodiment, the ammonium half amide salt or the diammonium salt of a diisobutyl acidic anhydride copolymer with a number average weight of approximately 1,000 to approximately 4,000 is used. The amount of the dispersant used varies depending on the type and type of pigment used and on the value and type of preparation used as the binder. In general, however, about 0.3 to about 3.5 parts by weight are free (Solid basis) per 100 parts by weight of the pigment effective for dispersing the pigment.

The dispersants of the type described above apparently decompose at the temperature maintained during firing, releasing ammonia or a lower amine which then volatilizes. τ% / η further increases Toggle _t that the carboxylic acid residues with either the amide group of the copolymer or with the aminoplast or with these two ingredients

509830/0989

react and become insoluble. Regardless of the mechanism involved, the fact that when this particular class of dispersants is used, no change in the excellent water resistance as well as other very desirable properties of the films is observed indicates that such catalysis is occurring. It could be shown that very clear materials, which contain a small amount of such dispersants, have better water and solvent resistance than the same preparations without dispersants, the two samples each under exactly the same conditions have been hardened. The amount of dispersing agents used in the clear preparations fluctuates depending on the A ™ rnoplastnenp: e used. TTn / re about 0.1 to about 1.0 part by weight of the dispersant per 100 parts by weight ("solids basis ^ der Vhevzv.p- ^ measures cause the desired catalysis.

The inventive 'H-ierzugraassen can be seen as clear masses, i.e., as non-pigmented clear top coats or protective coats or used as pigmented coatings.

In the latter case, the coatings can be left in a "lacquer-free" state, ie they can be left on the substrate without a further clear lacquer coating. When pigmented, the ratio of pigments to coating solids can vary considerably, depending on the pigment used and the intended application. The ratio of pip-ment to. Coating solids can vary from 1:20 to 20: 1. The clear coating compositions are particularly suitable as protective coatings, that is to say as coatings which are used to protect decorative coatings underneath, without their decorative effect being influenced in the process. Since the clear coatings according to the invention have a very

509830/0989

good clarity, high gloss, excellent solvent and Having water resistance as well as high adhesiveness to a wide variety of surfaces, they are very much considered Protective covers suitable.

The coating compositions according to the invention can be applied to a large number of substrates, the only limitation being the ability of the substrate to withstand the firing cycle which is essential for processing the coating compositions according to the invention. Metals are particularly suitable whether or not they have a primer coat. Iron, steel, Ohrom-plated steel, tin-plated steel, aluminum, copper, bronze or brass surfaces, especially in sheet metal or coil form, with thicknesses of 1.3 to 5.9 mm (0, 05 to 0.20 inches) are outstandingly suitable as substrates for the coating compositions according to the invention. Ceramic surfaces and in some cases wood surfaces are also suitable as substrates. For roll application, for example using a reverse roll coater, the thickness is 1.3 to 127 µm, and preferably 5.9 to 33.6 µm (0.05 to 5 or 0.2 to 1.5 mils) in not -hardened condition.

A variety of pigments can be used in the invention Coating compounds are used. The pigments used however, must be stable and non-reactive under alkaline conditions, i.e. at a pH between approximately 9 and about 1Ί. Typical pigments that are suitable are titanium dioxide, iron oxide, calcium carbonate, barytes and the various Clay types.

The coating compositions according to the invention are particularly suitable for application using a direct roller application device or a mandrel coating device, but they can also be applied in other ways, both

5098 30/0 98 9

-9L-

for example using a reversing roller coater or a spray gun. A single roller applicator applies the coating to the substrate while the application roller rotates in a bath made from the coating composition. "The coatings are then baked at a temperature of about 1? 1 to 1770" (250 to 3 ¹ SO ^0- P ¹ ) for a period of about -] / p to 10 minutes. The firing or curing volatilizes all of the volatile material in the "film, including residual water, traces of monomers, leveling agents, and tertiary amine. It is particularly important that the tertiary amine be volatilized as it inhibits the hardening of the aminoplast. The burning causes the ammonium or amine salts of the polymeric carboxylic acids to decompose, evidently releasing the acidic form of the copolymer, which can then react with the other components and become insoluble. The firing has the consequence that the aminoplast is hardened, which crosslinks the entire film and makes it insoluble.

The following examples show preferred embodiments of the Invention.

example 1

A water-soluble salt of 2 (dimethylamino) ethanol with a water-insoluble copolymer of ethyl acrylate / hydroxypropyl methacrylate / methacrylic acid / methyl methacrylate in a weight ratio of 46/5/3/46 (30 to 32% total solids by weight in a mixture of $ 90 water and 10 fo tert-butyl alcohol) is treated with a water-soluble melamine / formaldehyde adduct which has been modified by a reaction with methanol, and the molar ratio We lamin / formaldehyde / methanol is 1: 7: 12 (80 ° fo total solids in an equal Volume mixture of isopropanol and butanol) and 1.3 ^, based on weight

509830/0989

BAD ORiGiNAL

of the σ-total solids, a polyethylene glycol with a molecular weight of about? 0,000 (n ^ r ^ owax 20W) mixed. The weight ratio of the copolymer to the adduct in the mixture is 75:25. The preparation obtained has a pH of 8.6, a viscosity of approximately 75 Hps as / ie a ^ n. Total solids content of 36% by weight. The weight ratio of water to the alcohol in the system concerning ^h> t 87;. 13 The wet is directly on a tin-plated steel (40.3 kg) as rer Schnt.zlack for can bodies with 45 m per minute under "^ i"

a TJrethane roller with a Dummeter hardness of 20 t. The mass and flow properties of the mass are very good. The coated plates are baked at a temperature of 163 ° O (325 ° P) for a period of 10 minutes, with a uniformly smooth and hard coating with a The release properties of the coating composition of this example can easily be improved by the addition of 5% by weight of utylcellosolve, based on the weight of the total solids.

Example 2

"Sine Har ^ disnersion confused! By grinding? 50 parts by weight of the mass according to Example 1, 250 parts by weight of ^ itaudioxydpigment (DuPont TiPure H900) and 1 part by weight of a defoaming agent (Topco ^T TDW) in a ball mill. After this preparation for a period of 16 S + unden has been ground in the ball mill, 1 ^ 0 parts by weight are mixed with 133.5 parts by weight of the preparation of Example 1 and an equal volume mixture of water and dimethylaminop + hanol in a volume sufficient to achieve a viscosity from 60 to 70 seconds, measured with a toothed cup Wr. 2. The finished mass has a total solids content of about 53% by weight. The weight ratio of water to gol solvent is 87%. The pigmented

5Θ9830 / 0989
BAD ORlGiNAL

The coating is applied using a direct roller applicator with high-durometer urethane rollers (Duro ^ eter PO) on tin-plated steel (40.8 kg) in ^ orm of a white base coat for can bodies at 45 m per minute The flow and leveling properties of the coating compound are very good, the coated plates are baked for a period of 10 minutes at 16 ^{1 0} O ("525 °") . In this way, white, smooth coatings are obtained Mass of this "example can also be made using a pom-

be applied.

Is repeated, "each of these examples, with the Carbowax omitted is, then the compositions show no acceptable flow and leveling properties.

Claims (1)

- 21 - ■ Patent claims .1. Heat-curable mass, which can optionally be piped and preferably applied directly to substrates, in particular made of metal, by means of a roller or a mandrel application device, characterized by an alkaline aqueous mixture with a binder, which essentially consists of the following components: A. ) A water-soluble salt of a tertiary amine with a water-insoluble addition copolymer having a molecular weight of about 20,000 to? 00,000 from a mixture of copolymerizable monomers consisting essentially of 1) an ester of a (CL-CLg) alcohol with an α, ß-unsaturated Carboxylic acid, 2) 1 to 4% by weight of an olefinically unsaturated one Carboxylic acid and 3) about 3 to 20% by weight of at least one compound consist of hydroxy (Cp-C,) -alkyl esters an acid of the horn COOH where η is an integer with a fourth from 1 to 2 , and (C ₁ -C2) -alkyl esters of α-methylolacrylic acid is selected, B) a water-soluble condensation product of urea or a triazine with formaldehyde or a water soluble one Methanol or ethanol ethers thereof, where 5 09830/0989 C) the mass 1 "to 5 H-ev / ichts- ^ of a polyethylene glycol or a polyethylene oxide as a water-soluble one Rheology modifiers having a number average molecular weight of about 400 to 100,000, the percentage being based on the total weight of A) and B) (! Solids basis) relates, and wherein the weight ratio of A to B, based on "solid has is between 85: ¹ 5 and 65:35 fluctuates, the minimum film-forming temperature of the mass higher than is about 25 ⁰ C and the Peststoff" -ehalt the cask between 30 and 80 weights. 2. mass according to ΛηΏ-nmch 1, characterized in that the tertiary ami / n consists of 2-dimethylaminoethanol. 3. Composition according to Inspruch 1, characterized in that ( ¹ R-) is a urea / formaldehyde reaction product or a melamine / formaldehyde reaction product or a mixture thereof. 4. Dimensions according to claim. 1, characterized in that the reaction product of a urea / formaldehyde idduct with Methanol, the molar ratio urea / formaldehyde / methatiol is in the range of 1 / 1.75-3 / 2-3.5, or a melamine / formaldehyde adduct with methanol, the melamine / formaldehyde / methanol molar ratio being in the range of 1 / 7-10 / 12-17, or is a mixture of these. , ·. ·:. . ·. 5 .; Mass according to claim 2, characterized in that the Component d) an ester · of acrylic acid with an alkanal with is about 2 to 12 carbon atoms, component (2) consists of methacrylic acid, and component (3) consists of hydroxyethyl acrylate, methacrylate, hydroxypropyl erylate ", and / or -methacrylate is. 509830/0989 6. Wr π se nac "claim 5, characterized in that the Oopolynere contains methyl methacrylate. 7. Composition according to claim 6> characterized in that the copolymer "is a polymer of Itbylacrvlat, HydroxyOro-nylmethacrylat, Is methacrylic acid and methyl methacrylate. 8. Grasp according to .Ans-nruch 6, characterized in that the Rheology Modi fipierunp-smittel a polyethylene glycol · with a Molecular weight is from about 400 to 20,000. 9. Composition according to claim 6, characterized in that the rheoloptic modifier is a poly (ethylene oxide) with a molecule =? M-ewich " ¹ : which does not exceed approximately 100,000. 10. Composition according to claim 6, characterized in that they ¹ to 20 O tte wichts- ⁰ ^ be ^ o ^ s reputation in the mass of an organic T ^ ösunp-smittels FVJ "the non-^ ehä rtete ¹ ^ oIy-! Contains the solids Permischung. 11. Composition according to claim 6, characterized in that it contains a pigment, the relative G-weight of the ^ icments with respect to α-plus jx fluctuating between 5:95 and 60:40 (100 in total ). 12. Ver.fa.hren for decorating a substrate, characterized in that that on the substrate the mass according to claim T by means of a directly working roller, application device or a Dornauftra ^ svorrichtung applied in such an amount that a finished rehabilitated layer with a Pick from 1.3 to 112 µ (0.05 to 5 mils) and then heat the coating for a long time until it is heat set. 5 0 9 8 3 0/0989 BAD ORIGINAL 13. The method according to claim 10, characterized in that pekenti: indicates that the substrate used is a metal sheet that is exposed to the Hardening the coating is mechanically deformed. 14-. Method of coating and decorating a metal sheet, characterized in that the sheet is coated with the mass according to claim 5 in such an amount that the finished cured layer in a thickness of 1.3 to 112 u (0.0? "To 5 mils) is present, the coating is heated as long as until it is heat-hardened and then the sheet metal is mechanically deformed. 509 83 0/0989