NO754303L - - Google Patents

Description

The present invention relates to solid paint with dimensional stability based on ion bonding, and a method for its production.

Various resin mixtures consisting of homo- and copolymers with partially neutralized carboxylic acid groups are known. These contain between 3 and 20% carboxylic acid residues in which less than 50 percent of the carboxylic acid groups are neutralized with monovalent, divalent or trivalent cations. Prior art resins, known as ionomers, are desirable in industry because they combine the utility of a thermosetting polymer with the flow properties and processability of thermoplastics. Ionomers have lower densities than vinyl or cellulose plasters, and because of their similarity to. polyethylenes are used as protective films for food packaging. Ethylene-methacrylic acid copolymers are described in US patents 3,266,272 and 3,338,739 and in Belgian patents 674,595 and 600,397. Ethylene-sodium acrylate copolymers are described in BRD patent 1,645,471. Many of the desirable properties of these polymers such as e.g. stress fracture resistance, translucency, grease and abrasion resistance, low permeability, high elongation, tensile strength and low modulus of elasticity are believed to be partly due to a type of ionic bonding.

It has now been discovered that solid paint with gel properties

which are necessary to provide dimensional stability, can be prepared by cross-linking certain reactive polymers with "ionic clusters" having polar molecular components. This type of ionic bond differs substantially from the solvent-free ionic bond in the previously known compounds.

An object of the present invention is to provide a solid paint with dimensional stability based on ion bonding, i.e. "ion cluster cross-linking" of polymers, and gel strength reading of 100-200, comprising a mixture as stated in claim 1.

A further object is to provide a method for producing a solid paint with dimensional stability based on ion binding and a gel strength reading of 100-200, the method appearing in claim 7.

Solid paints with dimensional stability and desirable paint properties are achieved as mentioned by mutual influence between certain polymers with reactive functional groups and certain cross-linking agents which are formed by dissolving a metal hydroxide in a polar solvent with high dielectric strength.

Cross-linking of the polymer chains takes place by means of. "ion clusters"; consisting of multiple ions in connection with molecules in polar solvents. The term "solid paint" means a paint that has sufficient dimensional stability under storage conditions, i.e. is self-supporting, and can still be used as a paint stick (analogous to a piece of hard, butter or cheese). Such solid paint can advantageously be applied by hand to surfaces that are normally protected by paint, and products can be coated without the use of a brush or roller. For practical and protective reasons, such a paint stick will -usually be placed in a PJ skin or:-.a cover that is suitable for storage. Advantageously, such a protective layer has a closable opening. The solid paint can be applied by bringing the paint stick into contact with the surface to be painted followed by the usual vertical and horizontal movements over the substrate, so that a non-sticky, air-curable paint film is deposited. The shear stress produced by dragging the paint rod over the surface to be painted is sufficient to cause the solid paint to deform into a liquid coating at the contact point. Such a solid paint coating is such that it has the desired adhesion, flow and ability to evenly coat the surface. It is assumed that the solid paint according to the invention must contain common pigments, fillers, drying agents, binders and other additives so that films with desirable properties in terms of gloss, color and coverage are provided. It is assumed that such solid paint can be manufactured in blocks or rods with widths varying from 3 mm to approx. 2.5 m or larger and thus also makes it usable in industrial applications, such as e.g. "coil" coating of metal.

When the curable resin is a solution of a curable polymer in a non-polar solvent as stated in (1) in claim, the resins that can be used in the present invention include homo- and copolymers and mixtures thereof with suitable functional groups either built into the polymer or grafted onto them using the usual grafting technique. Useful resins include polyethers, polyesters, unsaturated polyesters, polyolefins, polyacrylates, vinyl resins such as polyvinyl chloride and polystyrene. Particular reactants and amounts are chosen so that resins with pendant and/or terminal functional substituents are obtained which are capable of further reaction with ionic reagents to form gels with appropriate dimensional stability and gel strength. Desirable application properties are achieved when the gel strength reading is 100-190 and preferably 135-180, when measured 25 hours after gelation. The gel strength is indicated in 0.1 millimeter units using a "Universal Penetrometer"; the lower the penetrometer reading, the higher the gel strength.

Regardless of which resin is used in carrying out the invention, it is crucial that the particular resin used is soluble in a non-polar solvent and that the resin has pendant and/or terminal functional, reactive groups that are easily ionizable. Anionic functional groups used to modify the resin are of the sulphonic, phosphonic and carboxylic acid type. The carboxylic acid functionality is particularly preferred since many polymers with such reactive ionizable groups can be easily purchased or synthesized. Preferred reaction products are those obtained by combining products are those obtained by combining carboxylic acid-substituted polyesters and alkyd polyesters with molecular weights in the range from approx. 1000 to 7000 which contains from approx. 1 to 4 reactive functional groups for every 2000 molecular weight units. Polyesters and polyethers with molecular weights... in the range of 400-2000 and which give solid paints with desired gel properties are particularly preferred. Alkyd resins modified with fatty acid groups and with terminal carboxyl functionality are shown in the examples. When it gels, where polyolefins, polyacrylates and other systems where air curing does not occur, a higher molecular weight is usually required, of the order of 100,000. However, 1 to 4 reactive, functional groups per

2000 molecular weight units. The alkyd resins that can be used in the execution of the present invention are produced by polymerizing the polymer monomers and other intermediate products by boiling at a temperature of approx. 204-316°C so that resins with an acid number (ST) in the range from 30 to 55 and preferably 41±2 are obtained.

Certain "longer" oil resins as exemplified in Examples 1

and 2, polymerizes at 232°C to a ST of 43.0.

The above-described polymers with ionizable, reactive groups dissolve in a sufficient amount of non-polar have the desirable adhesion, flow and uniform coating of the surface. It is assumed that the solid paint according to the invention should contain common pigments, fillers, drying agents, binders and other additives so that films with desirable properties are provided in terms of gloss, color and coating ability. It is assumed that such solid paint can be manufactured in blocks or rods with widths varying from 3 mm to approx. 2.5 m or larger and thus also makes it usable in industrial applications, such as e.g. "coil" coating of metal.

When the curable resin is a solution of a curable polymer in a non-polar solvent as shown in IA above, the resins that can be used in the present invention comprise homo- and copolymers and mixtures thereof with suitable functional groups either built into the polymer or grafted onto them by the usual grafting technique. Useful resins include polyethers, polyesters, unsaturated polyesters, polyurethanes, polyolefins, polyacrylates, polyhydrocarbons prepared from aliphatic and aromatic hydrocarbons with α,β-13 unsaturation, vinyl resins and chlorine-substituted vinyl compounds as well as other known combinations. Particular reactants and amounts are chosen so that resins with pendant and/or terminal functional substituents are obtained which are capable of further reaction with ionic reagents, so that gels with appropriate dimensional stability and gel strength are formed. Desirable application properties are achieved when the gel strength is from approx. 100 to 190 and preferably from 135 to 180, when measured 25 hours after gelation. The gel strength is indicated in millimeter units using a "Universal Penetrometer", the lower the penetrometer reading, the higher the gel strength.

Regardless of which resin is used in carrying out the invention, it is crucial that the particular resin used is soluble in a non-polar solvent and that the resin has pendant and/or terminal functional, reactive groups that are easily ionizable. Such ionizable groups include both cationic and anionic reactive functions. Anionic functional groups used to modify the resin are preferably of the sulfonic, phosphonic and carboxylic acid type. The carboxylic acid functionality is particularly preferred since many polymers with such reactive ionizable groups can be easily purchased or synthesized. Preferred reaction products are those obtained by combining carboxylic acid-substituted polyesters and alkyd polyesters with molecular weights in the range from approx. 1,000 to 7,000 containing from c. 1 to 4 reactive functional groups for every 2,000 molecular weight units. • Polyesters and polyethers with a molecular weight in the range of 400-2,000 and which give solid paints with desired gel properties are particularly preferred. Alkyd resins modified with fatty acid groups and with terminal carboxyl functionality are exemplified in the examples. In the case of polyolefins, polyacrylates and other systems where air curing does not occur, a higher molecular weight, of the order of 100,000, is usually required. However, 1 to 4 reactive, functional groups per 2,000 molecular weight units. The alkyd resins that can be used in the execution of the present invention are produced by polymerizing the polymer monomers and other intermediate products by fusion cooking at a temperature of approx. 204-316°C so that resins with an acid number (ST) in the range from 30 to 55 and preferably 41+2 are obtained. Certain "longer" oil resins as exemplified in examples o and. 2 is polymerized at 232°C to an ST of 43.0.

The above-described polymers with ionizable, reactive groups are dissolved in a sufficient amount of non-polar solvents so that solutions with a non-volatile (N.V.) content of from approx. 10 to 90 and preferably from 35 to 60% by weight. Particularly preferred are solutions with 50% N.V.

Suitable non-polar solvents for dissolving the polymer include both aromatic and aliphatic hydrocarbons and are chosen depending on the resin used, the functionality of said resin and the nature of the ionic reactant. Suitable solvents are usually hydrocarbons with boiling points of approx. 51.5 to 204 oC and containing up to 12 carbon atoms. These include hexane, heptane, octane, nonane, decane and mixtures thereof. Preferred hydrocarbons are the various octanes because of their suitable evaporation rates. White spirit is a particularly suitable solvent because of its availability and the desirable properties of the resulting solid paint.

In certain cases, aromatic solvents such as toluene and xylene are advantageously used, and they are particularly valuable in dissolving the high molecular weight polymers.

It should be understood that solvent, resin and amounts of each will vary and depend on the type of resin, solvent, filler and other additives required for a particular type of solid paint. The additives, drying agents and other common dispersing aids can be mixed with the resin solution using a "Cowles" stirrer. The order of addition is usually not critical. If desired, the pigments and other additives can be mixed with the resin material before dissolving the resin in the non-polar solvent. After the additives are thoroughly mixed, the resulting mixture is advantageously aged for 12

to 20 hours before reacting with the ionic component.

When the curable resin is a stabilized dispersion of a polymer in a non-polar, non-solvent as shown in I.B. above, the resins that can be used in the present invention comprise homo- and copolymers and mixtures thereof with suitable functional groups either built into the polymer chain or grafted onto it by conventional grafting techniques. Such resins include polyethers, unsaturated polyesters, polyurethanes, polyacrylates, vinyl resin and chlorine substituted vinyl compounds as well as combinations known in the art. The particular reactants and amounts are chosen so that resins with pendant functional substituents are obtained which can react further with ionic reagents so that gels with suitable dimensional stability and gel strength are formed. Desirable application properties are achieved when the gel strength is from approx. 130 to 210 and preferably from 150 to 195 mm when measured 25 hours after gelation. The gel strength is read in millimeters by using a "Universal Penetrometer". The lower the penetrometer reading, the higher the gel strength.

In the case of the resin of Type I.B. used in the practice of the invention, it is important that the particular resin be insoluble or only slightly swelled by the non-solvent, as is necessary for any non-aqueous dispersion, and that the resin has pendant reactive groups that are easily ionized. Such ionizable groups include both cationic and anionic reactive functions. Anionic groups used to modify the resin are preferably sulphonic, phosphonic and. carboxylic acid groups. The carboxylic acid functionality is particularly preferred since many polymers with such reactive ionizable groups can be easily purchased or synthesized. Preferred resins are copolymers of unsaturated hydrocarbons and unsaturated acids with molecular weights in the range of 100,000 to 300,000. Particularly useful resins for the practice of the invention are acrylic acid esters and vinyl polymers with a particle size range

of from 0.01 to 30 microns. Acrylate and methacrylate copolymers with terminal carboxy functionality are particularly preferred

and is illustrated in the examples. Non-aqueous dispersions (NAD) which are known and particularly useful in the practice of the invention (if modified so that they have ionizable positions on the surface) include those described by Dowbenko and Hart, Ind. Meadow. Chem. Prod. Res. Develop., vol. 12, no. 1, 1973, pp. 14-28. The polymers and stabilizers described therein are hereby referred to. In the formation of such NAD, the choice of amount and type of stabilizer is very important in order to obtain solid paints with desired application flow and coalescence properties. Other useful NAD resins include those obtained from poly(methyl methacrylate), polyacrylate and polymethacrylate and copolymers thereof obtained by addition polymerization with polyol-. veneer, such as polyethylene, poly (vinyl ether) ■, vinyl acetate, hydroxyethyl acrylate and 2-hydroxypropyl methacrylate.

The polymer resins which can be used in this aspect of the invention can be prepared by solution polymerization followed by dispersion in a non-solvent or by dispersion polymerization. The first method involves polymerization of the monomer or comonomer and other intermediates under free radical conditions at a temperature of approx. -46 to 121 o C so that a resin with an acid number is obtained. (ST) in the range from 20 to 80 and preferably from 25 to 60. The second and preferred method comprises polymerization of the monomer or comonomers and other intermediates in a non-solvent under free radical conditions at a temperature of approx. -46 to 121°c so that a resin dispersion with the desired acid number is obtained.

The above-described polymers with ionizable, reactive groups are dispersed in a non-polar non-solvent so that a dispersion is formed with a content of non-volatile (NV) substances of from approx. 10 to 90 and preferably from 30 to 60% by weight. Particularly preferred are dispersions with 50% NV. Suitable non-solvents include both aromatic and aliphatic hydrocarbons which are selected depending on the particular resin, the functionality of said resin and the nature of the ionic reactant. Generally, suitable non-solvents are hydrocarbons with boiling points of approx. 38 to 204°C and containing up to 12 carbon atoms. These include hexane, heptane,

octane, nonane, decane, dodecane and mixtures thereof. Preferred hydrocarbons are the various octanes because they have suitable evaporation rates. White spirit is particularly preferred as a solvent, as it is readily available and gives desirable properties to the finished solid paint. For some resin systems, aromatic hydrocarbons such as toluene and xylene are used.

It has been established that NAD resins can very well be blended with various known stabilizers. The function of these stabilizers is primarily to prevent the resin particle from coalescing during storage and during the production of solid paints. Useful stabilizers include those described and referenced in the above cited article by Dowbenko and Hart. Polyene stabilizers useful for certain solid paints include low molecular weight polybutadiene grafted onto an acrylic copolymer. For the present solid paints, NAD resin stabilized with copolymers of methyl methacrylate and glycidyl methacrylate and further reacted with 12-hydroxystearic acid and/or poly(lauryl methacrylate) is particularly preferred.

It should be understood that the non-solvent, resin and amounts of each will vary and depend on the type of resin, stabilizer, non-solvent, fillers and other additives required to make a particular solid paint. The additives, drying agents and other common dispersing aids are preferably mixed with the resin dispersion by means of a "Cowles" stirrer. The order of addition is not critical. The typical paint composition described herein is a latex-type non-aqueous resin dispersion, and it generally does not require special drying agents to provide suitable film properties. When drying agents are added, they are used in amounts of less than 2%

and preferably less than 1% by weight of the total mixture. The drying agents are added to the small amount of oil or alkyd that is usually added to the mixture to promote the dispersion of the pigment and promote the coalescence of the film. After application, the resin particles coalesce and fuse to form a dry film within minutes.

The polymer composition shown in IA (solution of polymer in a non-polar hydrocarbon) or the composition i

IB (stabilized dispersion in a non-polar non-solvent) is then mixed with the ionic cross-linking agent dissolved in a high dielectric polar solvent.

Suitable ionic cross-linking agents are usually inorganic salts, which upon dissolution give special cations or anions which can be combined with the terminal reactive groups in the resin so that ion clusters are formed which are responsible for the gel formation. Such clusters, containing the molecules of the high dielectric, polar solvent, act as reversible cross-links that connect the reactive resin molecules in tissue and thus impart gel strength and dimensional stability to the resulting solid paint. When the reactive terminal positions on the polymer are carboxylic acid groups (-COOH), the preferred cross-linking reactants are alcohol solutions of mono-, di- and trivalent metal hydroxides. Such crosslinking reactants include oxides and hydroxides of sodium, potassium, lithium, barium, calcium, manganese and magnesium. Equally effective cross-linking agents are the corresponding metal alkoxides such as e.g. sodium methylate. In some cases, ammonium hydroxide and organic cation formers such as e.g. tetramethylammonium hydroxide is used as cross-linking agent. The cross-linking gelation obtained by reacting sodium hydroxide with the above-described resin molecules with terminal or pendant carboxyl groups is particularly preferred. Suitable gels are obtained when an effective amount of cationic base is mixed with the free carboxylic acid functionality. In each case, an amount of base substantially in excess of that required for neutralization is required to be effective. By substantial profit is meant approx. 100-600 mol% ionic reactant dissolved in the polar solvent. Although the size of the excess varies with each particular resin system and depends on the molecular weight of the resin, the number and type of the ionizable functional group and the valence of the metal hydroxide, satisfactory gels are obtained when the ionic reagent is used in an excess of 100-600 moles %. When amounts of less than 100 mol% are used, the resins do not exhibit the required dimensional stability. When amounts greater than 600 mol% are used, the resins do not exhibit the desired wear and surface properties. To form gels, the metal hydroxide or another ionic cross-linking agent is added as a 10-50% by weight solution in a high dielectric, polar solvent to the polymer resin mixtures. Preferred solid paints were obtained by using 100 to 250 mol% sodium hydroxide based on the molar content of the reactive functional group, i.e. moles of free COOH.

The polar solvents that can be used for dissolving the ionic cross-linking agent are usually those solvents that have a dielectric constant greater than 10 and include aliphatic alcohols with 1 to 10 carbon atoms and 1 to 2 hydroxy groups. Although C, 1 -o-aliphatic alcohols are usually preferred, glycols containing similar carbon chains can sometimes be used in the production of solid paints with desired gel properties. Useful alcohols include methanol, ethanol, isopropanol, n-propanol, the normal and isomeric butanols, pentanols, hexanols, heptanols, octanols, as well as the corresponding glycols obtained therefrom. Methanol is the alcohol of choice because it is cheap, readily available, and the ionic reagents have favorable solubility in them. For certain applications, it is preferred to use glycols or mixtures of glycols and alcohols as the plasticizing carrier for the ionic reactant. Preferred glycols are ethylene glycol and propylene glycol, although the higher glycols such as pentanediol and hexanediol, for certain resins act as plasticizers and provide the desired smoothness. Additional high dielectric polar solvents that can be used in the practice of the invention include water, formamide, dimethylformamide and dimethylsulfide.

The metal drying agents which are suitable for solid paints are those known in the field and include the metal salts and/or esters of various organic carboxylic acids with up to 30 carbon atoms and mixtures thereof. The metal salts of cobalt, zinc, zirconium, magnesium, aluminum and manganese prepared from Cg_^2~lcarboxylic acids with (3 branched chains) are preferred desiccants. Typical paints as described herein required unusually large amounts of metal desiccants up to the order of about 0.5 to 5% based on resin weight The amount of desiccant required depends to some extent on the oil or sources of double bonds used in the paint system, i.e. the number and type of double bonds available.

A further aspect of the invention is the use of resins with pendant and/or terminal, functional, reactive groups in addition to acid or carboxylate groups. When the ionizable group in the polymer is a precursor of a cationic group instead of an acid or carboxylate group, the ionic crosslinking reactant will be an anionic precursor. Examples of cation formers are (1) primary, secondary, tertiary and cyclic amines, which react with hydrogen halides and hydrocarbon halides to form quaternary halides to form quaternary salts, (2) substituted phosphines which combine with halides to form phosphonium salts, (3) sulfides which react with alkyl halides to give sulfonium salts and (4) cyclic ethers which react with acids to give oxonium salts. Examples of crosslinking agents of anion origin are acetic acid, nitric acid, hydrochloric acid, sulfuric acid, and relatively short-chain organic polybasic acids such as e.g. oxalic, malic, succinic, maleic, adipic acid and corresponding anhydrides.

For industrial coating purposes, the solid paint block is advantageously placed in conventional holding and application devices. Such devices, which will vary with the properties of the substrate to be coated and which can be adapted for continuous application, usually include a device for holding the solid paint in and a mechanism for adjusting the pressure applied to the paint block so as to achieve suitable deformation and so that a liquid coating and film of suitable thickness is formed. Increasing the pressure applied to the solid paint will result in the deposition of a heavier coating. Although the present solid paints can be air dried, it should be understood that for industrial coating applications curing of the film can be accelerated by applying heat and other known energy techniques.

The following specific examples illustrate only a limited number of embodiments. All parts and percentages are given by weight unless otherwise stated. The desiccants used were commercially available, common desiccants. "White spirit" and "odorless white spirit" had a boiling range of 149-204°C, and 174-210°C, respectively. The stated molecular weights are number average molecular weights unless otherwise specified. Examples 1 to 12 exemplify polymer solutions of type IA, while examples 13 to 19 exemplify polymer dispersions of type IB. Examples 20 to 23 exemplify mixtures of Type IA polymer solutions used in conjunction with non-binding (no reactive acid functionality) non-aqueous dispersions.

Example 1

Resin A was prepared by polymerizing a mixture (in amounts as shown below) of trimethylolethane (TME), dehydrated castor fatty acid (DCOFA), azelaic dimer acid ("AZELAIC1110") and dimer acid "EMPOL 1014") at 238°C by fusion boiling to an acid number of 41 (41-2 normal range).

Resin B, a "longer" oil resin, was prepared in a similar manner to Resin A by polymerization at 232°C to an acid number of 42.0.

Resin C, prepared by using pentaerythritol

(PE) instead of trimethylolethane (TME), was polymerized at 238°C to an acid number of 42.0.

Resin D, prepared by using a combination of DCOFA and heavy oil instead of DCOFA alone, was polymerized at 238°C to an acid number of 43.0.

Example 2

Polyester resin A (25 parts) was mixed with 12 parts heavy oil, 13 parts white spirit, 2.0 parts cobalt desiccant (12% metal), 2.0 parts manganese desiccant (9.0% metal) and . 3.5 parts zircon desiccant (12.0% metal) to a solution in hydrocarbon, and the resulting mixture was allowed to mature at room temperature for 16 hours. Titanium dioxide (40 parts) and calcium carbonate (10 parts) were mixed with the resin solution under "Cowles "-shaking so that a measurement degree of 6 Heg-, man was achieved. Various amounts of sodium hydroxide were then added as a 25% by weight solution in methyl alcohol so that solid paints were obtained as indicated in Table II. Solid paint 2A showed a streaked film appearance, the paint was a little too hard, too much effort was required to apply it, i.e. it showed too much resistance when applied and the application properties were too hard. The solid paints 2B and 2C with gel strengths of 147 and 161 respectively showed satisfactory application properties and film appearance, i.e. not too much force was required to apply them and the resulting film was smooth. All three solid paints exhibited dimensional stability and provided a satisfactory dry coating when applied to a test panel surface.

Example 3

Resin C was compounded for the paints 3A and. 3B using the method used in example 2 and with the same relative amounts of resin, heavy oil, white spirit, cobalt, manganese and zircon desiccant, titanium dioxide and calcium carbonate. A third paint 3C was prepared in a similar manner and it contained 1.3 parts cobalt desiccant (12% metal), 0.5 part manganese desiccant (9% metal), 3.0 parts zircon desiccant (12% metal) and 0.19 part aluminum stearate. The solid paints formed by the addition of 25% methanolic sodium hydroxide identified as 3A, 3B and 3C all exhibited satisfactory gel strengths, application properties, film appearance and drying quality.

Example 4

Polyester resin C (25 parts) was mixed together in hydrocarbon solution with 12 parts heavy oil, 13 parts white spirit, 0.95 part cobalt desiccant and 2.1 parts zinc desiccant (16% metal). A new resin composition for Resin C was identical to the above except that it contained only 0.9 part cobalt desiccant and an additional 0.45 part manganese desiccant. Those resins and paints made from them which contained 50 parts titanium dioxide and no calcium carbonate are identified as 4A and 4b respectively in Table II. It will be seen that paints 4A and 4B with neutralization values of 160 and 170 exhibited gel strengths of 176 and 138 respectively.

Example 5

By repeating experiments 2A, 2B, 3A, 3B and 3C, but with

adding the drying agents after the addition of the pigment to the resins, equally acceptable gel strengths, application properties and drying rates were achieved.

Example 6

Paint blocks of approx. 10 x 15 cm were stored in thin "SÅRAN" (from Dow Chemical Company) for 6 months. Application of these paints to a test panel after the storage period showed no noticeable deterioration in application and film properties. In addition, solid paints prepared from the same resins, but with acid numbers in the range of 30 to 60, gave acceptable solid paint properties. Equally good results were obtained when oitikika, safflower, soya or linseed fatty acids were used instead of dehydrated castor oil fatty acid. The best application properties were obtained when the gel strength, measured with the "Universal" penetrometer, was between 130 and 180 mm. Gel strengths of 100 to 130 and 180-190 gave effective, solid paints with somewhat less desirable properties.

Example 7

Resin D was prepared by first esterifying the dehydrated castor fatty acid (168 parts) with trimethylolethane (120 parts) at a temperature in the range up to 249°C so that a product with an acid number of 4.0 is obtained. A transesterification was then carried out by further reaction with heavy oil (168.5 parts) in the presence of 2.0 parts lead oxide catalyst until the product was completely miscible in methanol. The resulting product was combined with "Azelaic 1110" (91.6 parts) and "Empol 1014" (555 parts) and boiled to an acid number of 43.0. The resulting resin had an approximate molecular weight of 1300.

A cationic resin E was prepared by condensing resin D (1040.4 parts) with N,N-diethylaminoethanol in the presence of lead oxide (2.0 parts) as catalyst using such reaction conditions that the predominant reaction was esterification rather than amide denaturation. After removal of water and excess N,N-diethylaminoethanol, resin E had a molecular weight of 1500.

Gelation of resin E was carried out by neutralizing (100 and 300%) a 50/50% by weight solution of Resin E in white spirit with 37% hydrochloric acid. The resulting solid paints had poorer properties than those from a corresponding gel neutralized to 200% with 32N sulfuric acid resulting in gel strengths of 100-150.

Example 8

Polyester resin C (25 parts) was mixed together in a hydrocarbon solution with 12 parts heavy oil, 13 parts white spirit, 0.6 part cobalt desiccant (12.0% metal), 0.6 part manganese desiccant (9.0 % metal) and 6.0 parts zircon desiccant (12.0% metal), and the resulting preparation was allowed to mature at room temperature for 16 hours. Titanium dioxide (40 parts) and calcium carbonate (10 parts) were mixed with the resin solution while shaking in a "Cowles" shaker to obtain a paint grade of W 6Hegman. Various amounts of sodium hydroxide were then added in the form of a 25% by weight solution in methanol under reduced pressure in a 'vacuum "Cowles"' so that a solid paint was formed (Table II).

This addition method reduces the chances of air being trapped in the "finished" solid paint. Paints 8A and 8B

(in Table II) exhibited superior film-emitting and application properties. Both paints were dimensionally stable and showed good drying when applied to a test panel surface.

Example 9

Resin F was prepared under free radical conditions as follows: 10 parts methacrylic acid, 90 parts lauryl methacrylate,

1 part bis(4-t-butylcyclohexyl)peroxycarbonate (initiator) and 300 parts white spirit were added to the reaction vessel. The polymerization was carried out by heating to 60°C and by maintaining this temperature for 2 hours while the mass in the vessel was stirred. Conversion of 99% was achieved. The acid value of the polymer was 65.0. About 100 parts of white spirit was removed by vacuum distillation.

Various amounts of sodium hydroxide were added in the form of a 25% by weight methanol solution to 75 parts of the 33% n/V resin with shaking as shown:

The two "clear" paints can be described as follows: Experiment A resulted in a product that was only dimensionally stable and showed poor application properties, i.e. when the paint was applied, the paint film was too thick and too strong (compared to the previous examples) is needed to pass the sample over the test panel.

Experiment B resulted in a stronger product which showed good dimensional stability (gel strength of approx. 160 mm penetration) and good application properties. Paint B showed very little resistance when applied. Both of these products resulted in a "dry" film on the test panel.

Example 10

Resin G, a 100% N/V dicarboxypolybutadiene with a molecular weight of 1410 and an acid number of 65.0, was mixed into the following solid paint system:

Paint A with a gel strength of 250 did not exhibit dimensional stability. The paints B, C and D were dimensionally stable. During application, paint B tended to give too thick a film and was a little too elastic, i.e. tended to be slightly "taffy". Paint C was too hard and for this reason it had poor application properties. Paint D showed dimensional stability and acceptable application. All paints produced a dry film on the test panel.

Example 11

Alkyd resin H was prepared by polymerizing a mixture of 146 parts trimethylolpropane, 146 parts pentaerythritol, 908 parts dehydrated castor oil fatty acid and 413 parts azelaic dimer acid ("AZELAIC 1110") at 249°C by fusion boiling to an acid number of 42. resin exhibited a viscosity of z2 determined using the Gardner-Holt bubble tube test method ASTM D1545.

Alkyd resin I was prepared by polymerizing a mixture of 116.5 parts of trimethylolpropane, 116.5 parts of pentaerythritol, 296 parts of dehydrated castor oil fatty acid and 821 parts of azelaxn dimer acid ("AZELAIC 1110") at a temperature of 238 oC

to an acid number of 30. The resulting resin exhibited a viscosity of z2+ (Gardner-Holt).

Example 12

Solid paints were prepared from the resins H and I according to the method in example 2 with the exception that the drying agents were allowed to mature at room temperature for 1/2 hour, the order of addition being as indicated in the following table with a paint degree of 5 1/2 Hegman .

<a>) a diluted alkyd resin which cannot directly participate in ion binding,Reichold Chemicals (Canada) Ltd.<b>) "Dramatone" is a hot brand product of Glidden-Durkee, Division of SCM Corporation.

<cj>Pennsylvania Class crystalline silicon dioxide product

Sand Corp.

d) Johns-Manville Co. diatomaceous silica product.

e)

<e>) Filler product from N.L. Industries.

The solid paints 1, 2 and 3 exhibited dimensional stability and properties equivalent to or superior to the solid paint products of the previous examples. When applied to a substrate by contact and hand pressure, desirable surface films were obtained which air-cured overnight.

Preparation of NAD resins

The NAD resins 1, 2, 2A, 3 and 4 were prepared by addition polymerization of various monomers in the presence of non-solvents, free radical initiators and various stabilizers in the relative ratios shown in Table III. A small portion of the monomers is added to the polymerization vessel with the non-solvent and approx. 50 percent of the desired stabilizer, and the polymerization is started by heating to the reflux temperature in the range of 70-80°C. Next, the rest of the monomers, stabilizer (30%) and free radical initiator are added together with ethyl acrylate in a feed stream, while the acidic component, i.e. methacrylic acid and remaining stabilizer (20%) are added in a separate feed stream during a two to three hour addition period at the reflux temperature.Additional initiator

(1/4 of the total amount) is introduced into ethyl acetate in two portions during a further reaction period of 2 hours. After reflux treatment for a further 2 hours, the low-boiling solvent is removed by heating to approx. 90°C. For the present invention, it is important that NAD is produced with the carboxyl positions (or ionizable positions) on the surface of the particle (or that at least the majority is available on the surface) to provide the outer acidic positions on the suspended polymer particles. in this case, the supply of acids was started 10 minutes after the other supplies had started, and the supply of acids was finished approx. 10 minutes after mono-

the additional addition was finished.

Variations of the conditions shown in this example can be used as long as a stable NAD is produced where the acidic positions are available for gelation and are not buried in the particle body. It is recommended to perform an acid number determination on NAD.

Preparation of NAD stabilizer

1000 parts of 12-hydroxystearic acid, 3.5 parts of tetra-isopropyl titanate and 60 parts of xylene were heated together at 200°C under a nitrogen atmosphere. The reaction was controlled by collecting the by-product water. The resulting product had an acid number of 34.2 (calculated 33). This product was then reacted at 90°C under nitrogen with 82.3 parts of glycidyl methacrylate using 400 parts of methyl ethyl ketone and 10 parts of triethylamine to give another intermediate with an acid number of 4.3 and a content of non- volatiles of 93.4.. (The methyl ethyl ketone was removed by evaporation at the end of the reaction). This second intermediate (321 parts) was polymerized under free radical conditions with 225 parts of methyl methacrylate in the presence of ethyl acetate (500 parts), dodecyl mercaptan (1.5 parts) and azoisobutyronitrile (3.0 parts) as free radical initiator. The stabilizer was obtained in a yield of 98%.

Preparation of alkyd modifier

A polyester alkyd condensation polymer was prepared by condensing 136 parts pentaerythritol, 560 parts dehydrated castor oil fatty acid, 135 parts "Azelaic 1110" dimer acid and 168 parts "Empol 1014" dimer acid by fusion boiling at 238°C to prepare a alkyd resin with reactive carboxylic acid functionality, acid number of 41 and molecular weight of 1500.

Example 13

Resin NAD-2 (87 parts 50 N/v suspension in white spirit) was mixed with 30 parts alkyd modifier and 120 parts titanium dioxide to a #6Hegman grind. No drying agents were used in the mixture. Similarly, resin NAD-2A (94 parts 50th NV in white spirit) was mixed with 25 parts alkyd modifier and 115 parts titanium dioxide. Various amounts of sodium hydroxide (25% solution in methanol) were then added to form the solid paints identified in Table IV as Trials LA and IB. Solid paints IA and IB with respective gel strengths of 164 and 185 exhibited dimensional stability, had good application properties and a satisfactory dry coating when applied to a test panel. By good application properties is meant that when the paint is passed over the test panel, an even paint film is transferred to the panel and the work to do this is not too great.

In a third paint, resin was NAD-2 (94 parts 50 NV

in white spirit) mixed with 25 parts alkyd modifier, 115 parts titanium dioxide, 0.5 part cobalt desiccant (12% cobalt), 0.5 part manganese desiccant (8% metal) and 4.0 parts zircon desiccant medium (12% metal). The drying agents were added for the alkyd modifier. 16.1 parts sodium hydroxide (25% methanol solution) was then added so that the solid paint identified in Table IV as trial IC was produced. This product exhibited dimensional stability, had good application properties and exhibited excellent drying properties when applied, on a test panel.

Example 14

Resin NAD-1 (110 parts) was mixed with 100 parts titanium dioxide, 0.015 part cobalt desiccant (12% cobalt), 0.10

part zircon desiccant (12% zircon) to a grinding grade of W 6 Hegman to three mixtures A, B and C. which contained respectively 5, 10 and 15 parts tall oil alkyd (100% solids). Various amounts of sodium hydroxide were then added in the form of a 25% methyl alcohol solution to produce the solid paints identified in Table IV as trials IIA, IIB and IIC. The solid paints IIA and IIB with gel strengths of 135 and 195 respectively showed satisfactory application properties. Solid paint IIC showed poor application properties. All three solid paints exhibited dimensional stability and gave a satisfactory dry coating when applied to a test panel.

Example 15

Resin NAD-2 (105 parts) was mixed with 100 parts titanium dioxide, 0.015 part cobalt desiccant (12% cobalt), 0.10 part zircon desiccant (12% zirconium) and 10 parts tall oil alkyd (100%). Various amounts of sodium hydroxide were added in the form of a 25% by weight methyl alcohol solution so that the solid paints identified in Table IV as experiments HIA and UIB were produced. The solid paint HIA with a gel strength of 240

had poorer application properties (too soft, strong resistance)

than paint UIB with a gel strength of 190, which had good properties.

Although the paints exhibited dimensional stability, the film appearance was poor due to unsatisfactory coalescence.

Example 16

Resin NAD-3 (101 parts) was formulated as indicated for NAD-2 in Example 13 above by using 10 parts tall oil in one case and by replacing the tall oil with 15 parts polyester alkyd modifier in another case. The corresponding solid paints which were prepared by adding a 25% by weight sodium hydroxide solution in methanol are identified in Table IV as solid paints IVA and IVB respectively. The solid paints IVA and IVB with gel strengths of 150 and 200 exhibited dimensional stability and satisfactory application and film properties.

Example 17

Paint blocks approximately 10 x 15 cm in size formed from the solid paints described above were stored wrapped in thin "Såran" (from Dow Chemical Company) for 6 months. Application of these paints to a test panel after the storage period showed no noticeable reduction in application and film properties. Several solid paints prepared from the same resins but with acid numbers in the range of 25 to 60 gave acceptable solid paint properties. The best application properties were obtained when the gel strength as measured by the "Universal" penetrometer was between 130 and 195 mm, although compositions with gel strengths ranging from 100-130 and 195-200 produced effective solid paints with somewhat less desirable properties.

Example 18

Resin NAD-4 (94 parts 50 NV suspension in white spirit) was compounded and mixed to a grind grade of #6 Hegman with 30 parts alkyd modifier, 100 parts titanium dioxide, 15 parts calcium carbonate, 0.65 part cobalt desiccant (12 % cobalt), 0.65 parts manganese desiccant (8% metal) and 6.0 parts zircon desiccant (12% zirconium). Sodium hydroxide (25% methanol solution) was then added to form the solid paint as are identified in Table IV as experiment VIA. This solid paint had good application properties, exhibited dimensional stability and a dry film on a test panel.

Example 19

A "non-aqueous dispersion" was prepared without the use of added stabilizer. A monomer system was chosen that only partially swelled in the non-polar solvent, which was sufficient to maintain stability of the dispersion.

In this case, 780 parts of butyl acrylate, 100 parts of methacrylic acid, 8 parts of dodecyl mercaptan, 12 parts of azobisiso-butyronitrile and 600 parts of white spirit were added to a reactor. The mixture was brought to and held at 80°C for 5 hours. The conversion was 97%, the acid value of the dispersion was 43.7. The theoretical acid number is 72, i.e. that a certain amount of the acid is hidden when this production method is used.

Two aliquots each of 180 parts (60 percent NV resin) were mixed with 25.0 parts (200% neutralization) and 37.5 parts (300% neutralization) sodium hydroxide as a 25% methanol solution. Both products showed dimensional stability. However, the application properties were poor.

This product is not proper NAD and can best be described as a very coarse dispersion. However, this points to the possibility of internal stabilization, by a judicious choice of monomers. This system is not so stable and many of the ionizable positions are buried.

Example 20

Preparation of non-binding NAD resin in non-aqueous dispersion.

NAD resins of the non-binding type (i.e. without reactive functional positions - no gelation positions) were prepared by addition polymerization of various monomers in the presence of non-solvents, free radical initiators and stabilizers, an example of which is given in the table below. A small portion of the monomers is added to the polymerization vessel with the non-defrosting agent (white spirit etc.) and approx. 50% of the desired stabilizer and polymerization. is started by heating to 75-80°C. After approx. After 15-30 minutes, the addition of remaining monomers, stabilizers, etc. begins and continues for 3-4 hours. The mixture is kept at the reaction temperature for a further 1 hour, then cooled so that a milky dispersion with low viscosity (100-200 cP) and a content of non-volatile substances of 46% by weight is formed.

Example 21

Although many different NAD stabilizers of the type exemplified in Examples 13-19 are suitable for the preparation of non-binding NAD resins, the following illustrates the preparation of a particularly desirable and useful stabilizer: 900 parts 12-hydroxystearic acid, 3, 1 part of tetra-isopropyl titanate and 90 parts of odorless white spirit were heated together at 210°C under a nitrogen atmosphere. The reaction was carried out by collecting by-product water. The resulting product had an acid number of 36 (calculated 33)• The product was further reacted at 88°C under nitrogen with 9 7.6 parts of glycidyl methacrylate using 10 parts of triethylamine as catalyst. This fraction product had an acid value of 1.8 and a non-volatile content substances of 91.0. This second intermediate (440 parts) was polymerized under free radical conditions at 85°C using 2.0 parts of azobisisobuyronitrile with 300 parts of methyl methacrylate in the presence of odorless white spirit (800 parts). The product was reduced with 300 parts odorless white spirit. The final content of non-volatile substances was 38% by weight.

Example 22

Alkyd resin J has binding positions and is particularly useful in the production of solid paints in combination with the non-binding resin NAD resin in non-aqueous dispersion shown in Example 20. It was prepared by polymerizing a mixture of 295 parts trimethylolpropane, 690 parts dehydrated ricin -nusol fatty acid, 340 parts azelaic acid dimer ("Azelaic 1110") and 423 parts "Empol 1014" at a temperature of 250°C to an acid number of 42. The resulting resin gives a Gardner-Holt viscosity of z2.

Example 23

Solid paints were prepared from resin J using the following compositions:

The materials were added in the order indicated, except that half of the amount of NAD (50 parts) was kept aside until the product was split (ie, all pigments were added). The painting grade was 5 1/2 Hegman. After the remaining NAD was added and the mixture cooled, the drying agents were added. The drying agents were allowed to mature for 1/2 hour before sodium hydroxide-methanol was added with agitation under reduced pressure in a "vacuum Cowles" so that a solid paint was formed. This method of addition reduces the chances of entrapping air in the "final" solid paint.

Both paints showed dimensional stability. When rubbed (by hand) onto a substrate, paint was transferred to the substrate as a film. Both films dried overnight.

The solid paints formed by combining non-binding NAD resins with minor amounts of ion-bonded Type IA resins, exemplified in Examples 1-12 and 22, are particularly suitable for the sales (consumer) area of the coating industry. -strien as well as for commercial coating applications such as e.g. maintenance coating and coil coating. The particular advantage of such combinations and combinations between NAD resins and ion-binding resins (both binding and binding types) is that dimensional stability is retained with fewer binding positions,

while application and film properties are significantly improved.

Example 24

Change in ratios in non-binding NAD resins shown in Example 23 from 75 to 200 parts NAD resin per 25 parts ion-bound resin will give equally satisfactory dimensionally stable, solid paints.

The above examples illustrate the best way of carrying out the invention.

Claims (10)

1. Solid paint with a gel strength reading varying from 100 to 200 and a dimensional stability based on ionic bonding, characterized in that it comprises a mixture of: a) a polymer product selected from: (1) a solution of a curable polymer resin having a molecular weight of from 1000 to 7000 and sufficient reactive acid functional groups selected from carboxylic, sulfonic and phosphonic acid groups to provide an acid number of 20-80, wherein the reactive acid group is preferably a carboxylic acid group which is present in amounts from 1 to 4 per 2000 molecular weight units, the resin being dissolved in a non-polar solvent to provide a 25-90% by weight solution; (2) a stabilized anhydrous dispersion of a resin having a molecular weight in the range of 25,000 - 1,000,000 and sufficient reactive functional groups selected from carboxylic, sulfonic and phosphonic acid groups to provide an acid number of 25-60, the resin being dissolved as a 25-90% by weight suspension in a non-polar non-solvent; wherein the resin in (1) or (2) is preferably a homopolymer or copolymer selected from the group consisting of alkyd resin, polyester, unsaturated polyester, polyether, polyolefin, polystyrene, polyvinyl chloride, polymethacrylate, polyacrylate, or mixtures thereof; (3) a mixture of a non-binding NAD resin comprising a stabilized dispersion of a polymer having a molecular weight in the range of 25,000 - 1,000,000 dispersed as a 25-90% by weight suspension in a non-polar non-solvent, the resin not having some sites for reactive functional groups, with an ion-binding resin solution as defined under (1), the ratio of non-binding NAD resin to ion-binding resin being from 2:1 to 8:1; and b) an ionic cross-linking agent selected from metal hydroxide, ammonium hydroxide and an organic cation former dissolved in a high dielectric strength polar solvent to provide a 10-50% by weight solution or suspension; whereby the paint contains from 100 to 600 mol% of ionic cross-linking agent per mole of acid functional group. 2. Paint as stated in claim 1, characterized in that the cross-linking agent is a metal hydroxide; the polar solvent is a C1-6 aliphatic alcohol; and the functional group is a carboxylic acid group. 3. Paint as stated in claim 1 or 2, characterized in that the polar solvent is methanol and the cross-linking agent is sodium hydroxide. 4. Paint as set forth in any one of claims 1-3, characterized in that the resin dissolved in a non-polar solvent is. a polyester resin with a molecular weight of 1500-3500 and an acid number of 38-48 and is dissolved in 1 white spirit, and that the ionizing cross-linking agent is sodium hydroxide which is present in 220-280 mol% excess based on the acid functional group. 5. Paint as stated in any one of claims 1-4, characterized in that the water-free dispersion is formed from a vinyl acetate/ethyl acrylate/methacrylic acid terpolymer resin with a molecular weight of 100,000-300,000 and an acid number of 25-80 which is reacted with 210 -250-mol% sodium hydroxide as a 25% by weight solution in methanol. 6. Paint as stated in any one of claims 1-5, characterized in that the polymer product comprises a mixture of a non-binding anhydrous dispersion with an ion-binding resin solution, the ratio between the former and the latter being from 2:1 to 4:1. 7. Method, for manufacturing.of a. solid paint with dimensional stability based on ionic bonding and a gel strength reading of 100-200, characterized by (a) dissolving or suspending a curable polymer resin to form the respective polymer product according to claim 1, in such an amount as to provide sufficient reactive acid functional groups necessary for the stated dimensional stability when cross-linking with ionic cross-linking agents; (b) mixing pigments, fillers and colorants into the resin solution; (c) adding, with vigorous stirring, a 20-30% by weight solution or suspension of metal hydroxide in a C₁-g-aliphatic alcohol containing 100-600 mol% of the amount of metal hydroxide necessary to neutralize the reactive acid groups in the resin. 8. Method as stated in claim 7, characterized in that a polyester alkyd resin with a molecular weight of 1500-3500 and an acid number of 38-48 is reacted with 210-250 mol% sodium hydroxide in the form of a 25% by weight solution, per moles of carboxylic acid groups. 9. Method as stated in claim 7, characterized in that the resin is dispersed in a non-polar non-solvent in the presence of a stabilizer, the dispersion containing 30-60% by weight of resin. 10. Method as stated in claim 7, characterized in that a resin mixture is used which comprises a non-binding anhydrous dispersion and an ion-binding resin solution in a weight ratio of from 2:1 to 4:1.