FI62677C - RELEASE COMPARTMENT FOR ETF POLYMERIZED HARTS MEDICINE-CONTAINING GROUP OR FOR RELEASE MEDIA WITH BOCKERADE PROCESSOR - Google Patents

Description

E35r * l ΓβΙ advertisement publication rj n lBJ (11) UTLÄGGNINGSSKIUFT 0 ^ 611 c ivaten tti eiySnnetty 10 02 1933

Limjjrj Patent eeddelat - (S, J M.W 'C 09 D 3/72 ENGLISH — FINLAND ¢ 1) 751603 (22) HtiMmlspUv · —AnaAluilngadtf 30.05.75' '(23) AMcupUvt — GHtlgkMdac 30.05.75 (41) Tullut JulklMW — Bllvlt offumHt 22.12.75

Fatunttl · · and the National Board of Registration .... „.. .__. ,,., ..

. , .._, (44) Date of dispatch and date of issue. - Qo

Paten »· ech registerstyreisen '' Antokin« ι · *! och utUkrtften pubticarad 29-10.82 (22) (33) (31) Fjnrdittjr stuolksm - Btftrd prlorltot 21.06.7 ^ 09.08.7U usa (us) U8188U, U96066 (71) Grow Group, Inc-, PanAm Building, 200 Park Avenue, New York,

New York 10017, USA (72) Ivan H. Tsou, Bloomfield Hills, Michigan, USA (7U) Berggren Oy Ab (5U) A coating composition consisting of a polymerized resin having isocyanate-reactive groups and a crosslinking agent comprising The present invention relates to a coating composition, in particular a powder coating composition, isocyanate group per molecule, and is prepared from an isophorone diisocyanate, a preservative, and a compound having at least two isocyanate-reactive groups, which compound softens the coating composition both during and after curing.

Known coating compositions, especially powder coating compositions, have poor spreadability during curing and films have poor gloss. In addition, high temperatures are required for fusion while the crosslinking reaction temperature is even higher, about 190-260 ° C. Furthermore, known materials tend to agglomerate when stored at low temperatures, such as 21-27 ° C, and coatings are brittle, lacking flexibility and adhesion.

2 62677

The solution to these problems would be to use the purest possible crosslinking agent compatible with the polymerized resin. In addition, the crosslinking agent should cause spreading at the desired low temperature as a solvent and act as a plasticizer for the resin, however, it should be stable below the desired storage temperature. It should also have functional groups that crosslink with the resin at the lowest possible temperature and, after crosslinking, become part of the film and act as an internal plasticizer.

U.S. Pat. No. 3,660,143 discloses a radiation-curable paint binder having an adduct of a hydroxy-functional acrylic rubber particle, a diisocyanate and hydroxyalkyl acrylate and vinyl monomers.

U.S. Pat. No. 3,542,586 discloses a radiation-curable paint in which a vinyl binder contains monoester groups.

U.S. Pat. No. 3,317,463 discloses the use of protected isocyanate compositions (protected by sterically hindered phenols) in the preparation of urethanes, while U.S. Pat. No. 3,583,943 discloses the protection of an isocyanate group with ketoxifers.

U.S. Pat. No. 3,621,000 discloses a protected isocyanate having a bifunctional polyether.

U.S. Pat. No. 3,659,003 discloses a copolymerized acrylic resin which is reacted with a monoprotected diisocyanate to produce casting powders. All prior art products have the difficulty that there is no simple way to apply a plasticizer effect to a crosslinked polymerized resin in an effortless manufacturing step in resin film formation, as described above.

Furthermore, all previous products in the art have the difficulty · that there is no way to form a powder preparation that can be quickly cured to the desired film at low temperature.

62677 The coating compositions of this invention, especially the powder coating compositions, can be cured at a low temperature resulting in an adhesive film. Due to the need for a desired powder coating composition capable of providing the surface coating quality required in the forklift and automotive industries, there has been a need to achieve such a low temperature cure of a film-forming composition without, however, caking of the powder. The powder composition should have the ability to spread prior to the curing operation. Should agglomeration or agglomeration of the powder particles occur, it is recommended that it take place at the highest possible temperature. However, in order to save energy by using less heat for curing, it is best that the powder composition has the lowest possible curing or crosslinking temperature. Therefore, the softening point of the powder composition should be relatively narrow. Furthermore, when the protected isocyanate is used as a crosslinking agent, it is recommended that when the isocyanate group is released, there should be little or no gas formation during the curing operation. The present invention therefore relates to a coating composition for the preparation of solvent-resistant coatings consisting of a polymerized resin having isocyanate-reactive groups and a crosslinking agent containing at least two protected isocyanate groups per molecule, which is prepared from an isophoronide isocyanate, at least two isocyanate-reactive groups which soften the coating composition both during and after curing. The coating composition of the invention is characterized in that the crosslinking agent is prepared by first reacting the isophorone diisocyanate with a preservative such that the most reactive of the two isocyanate groups is protected and then with a plasticizer.

This invention relates to a coating composition, preferably a powder coating composition, which can be applied to a desired substrate and which, when heated, forms a hard, adhesive film. The powder used in this case is generally a very fine powder having a particle size range of about 0.1 to 250, preferably 1 to 150, and most preferably about 10 to 100, and its average diameter of 4,626,77 is preferably less than 35.

The substrate on which the coating is applied may be un primed metal, plastic, glass, etc. It should be noted that a conductive layer such as carbon or metal may be applied to the non-conductive surfaces before the coating of the present invention is applied.

This is especially the case if the powders are to be electrostatically deposited on a charged substrate. If it is not desired to apply such a conductive layer, it is possible to heat the substrate so that particles can adhere to it. It has been found that the desired surface coating grades can be achieved by using a metallic substrate. Although the metallic substrate can be purified by normal cleaning techniques such as chlorinated hydrocarbon, alkali and the like, the powder can be applied directly to the metallic substrate without using a normal corrosion-resistant phosphate coating preparation. However, in some cases, it has been found desirable to achieve long-term corrosion resistance with powder coatings by applying a corrosion-resistant phosphate coating composition to a metallic substrate.

Thus, one component of the coating composition is a polymerized resin having isocyanate-reactive groups. In other words, the resin is already polymerized, but has functional groups that can react with the isocyanate group of the crosslinking agent. Crosslinking occurs during curing (usually by heating) of the powder coating.

Examples of polymerized resins having isocyanate-reactive groups are preferably thermoplastic resins, although thermoplastic resins may also be used. A preferred polymerized resin is one containing reactive groups having displaceable hydrogen atoms, such as those present in a hydroxyl group, an amino group (primary or sedundary amino group), a mercapto group, an amido group, etc. It is assumed that hydrogen atoms are or an ester exchange of the carbonyl addition reaction may occur in which the isocyanate group is not regenerated but an intermediate is formed. The resin may be a polymerized, ethylenically unsaturated material such as acrylic, methacrylic, vinyl or polyester resin or the like. A preferred polymerized resin is one in which the monomer has the formula ^ R ^ -O- (O) C7-A- ^ C (O) O-R 2 where n and t are 0 or 1 and n + t is 1-2; wherein A is an alkenyl or alkenylene group having 2 to 8 carbon atoms or a substituted group thereof, wherein the substituent may be a chlorine, carboxy or cyano group; it should be noted that A may be branched or straight chain; and R and R 1 may be the same or different groups and may be hydrogen atoms, alkyl groups having 1 to 20 carbon atoms and preferably 2 to 8 carbon atoms, 1 to 20 carbon atoms, preferably 2 to 8 carbon atoms, and even more preferably 2 to 5 carbon atoms. .substituted alkyl groups, primary or secondary amino-substituted alkyl groups having 1 to 20 carbon atoms and preferably 2 to 8 carbon atoms; wherein the substituent of the amino group is an alkyl or hydroxyalkyl group having 1 to 6 carbon atoms; A mercapto-substituted alkyl group having 1 to 6 carbon atoms; A mercapto-substituted alkyl group having 1 to 20 carbon atoms and preferably 2 to 8 carbon atoms; an alkylthioalkylene group having up to 20 carbon atoms and preferably up to 8 carbon atoms and a group having up to 8 carbon atoms and containing an oxirane ring, most preferably 3 carbon atoms such as a glycidyl group.

Of the above monomers, the most preferred are those in which n + t = 1, especially acrylic and methacrylic resins, etc.

Examples of suitable acids for the above monomers include acrylic, methacrylic, itaconic, ethacrylic, maleic, fumaric acid, etc .; suitable examples of alkyl esters are those in which the alkyl group is a methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, ethylhexyl, octyl, decyl, dodecyl group, etc .; suitable examples of the hydroxy-substituted alkyl group include hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl, hydroxyhexyl, hydroxyoctyl, hydroxydecyl, hydroxydodecyl group, etc .; suitable examples of aminoalkyl groups include aminomethyl, aminoethyl, aminopropyl, aminobutyl, aminopentyl, aminohexyl, aminooctyl, aminodecyl and aminododecyl, wherein the amino group is a primary or secondary amino group and the substituent on the amino group is 1- An alkyl group having 6 carbon atoms and preferably 1 to 4 carbon atoms; suitable examples of mercaptoalkyl groups include methyl mercapto, ethyl mercapto, propyl mercapto, butyl mercapto, pentyl mercapto, hexyl mercapto, octyl mercapto, decyl mercapto and dodecyl mercapto, etc .; similarly, alkoxyalkyl and alkylthioalkyl groups may be methoxymethyl, ethoxymethyl, ethoxyethyl, methylthiomethyl and ethylthioethyl, etc.

It should be noted that although the polymerized resin may be a homopolymer, it is most desirable to use a mixture of monomers to provide various properties such as better cracking resistance, chalking resistance, adhesion, gloss, flexibility, strength, hardness, spreading, caking resistance and solvent resistance.

The preferred polymerizable monomer mixture is one having a relatively large number of esters (R or in the above formula is an alkyl or substituted alkyl group in which the substituent is non-functional or non-reactive) (about 50-90%); a minor amount (about 0.1-5%) of an acid (R or R 1 is a hydrogen atom) and a substantial amount (about 5-25%) of a functionally substituted alkyl compound (R or R 1 is an alkyl group having a reactive isosyanaattifunktionaalisuutta).

In addition, other copolymerizable monomers having an ethylenically unsaturated group may be added to the mixture in minor amounts (about 0.1-10%), such as: aliphatic or aromatic vinyls (e.g., vinyl chloride, vinyltoluene, styrene, etc.).

All that is required of a polymerized resin is that it have isocyanate-reactive groups, such as those listed above.

7 62677

The polymerization reaction of the above monomers uses a standard polymerization technique using catalysts, accelerators, etc. The preferred method is solution polymerization in various organic solvents.

Since the composition is to be preferably used as a powder coating composition, the curing temperature should be as low as possible. Therefore, it is recommended that the molecular weight of the polymerized resin be relatively low, such as about 10,000 to 75,000, and the deviation from the number average value be as small as possible. In other words, in order to achieve such curing, the molecular weight range of a given copolymer must be as narrow as possible and still in the above-mentioned range.

It should be noted that a low molecular weight resin is needed to achieve the desired spread, film appearance, less "orange peel" appearance, etc. The narrow molecular weight distribution results in high caking temperature, better spreading, better glossy appearance and better compatibility of the powder.

The crosslinking agent

The crosslinking agent used as a component of the powder coating composition is, as mentioned above, an isophorone diisocyanate in which the most reactive isocyanate group is protected and others are allowed to react with a compound which forms an internal resin plasticizer after curing but which forms an external resin plasticizer before curing. By "internal plasticizer" is meant a material that provides a plasticizer effect in the resin and is chemically bonded thereto. By "external plasticizer" is meant a similar material that is not chemically bonded. The most reactive isocyanate group is that which is attached to the 6-ring via a methylene group. During curing, this group cleaves and reacts with the functional groups of the polymerized resin.

By "protected isocyanate" is meant an isocyanate group which has been reacted with a protective agent and which reaction product is stable up to about 50 ° C over a long period of time. During the curing of the powder coating composition, the protected isocyanate becomes unprotected, e.g. during drying at about 125-200 ° C.

Saturated aliphatic glycols or polyhydroxyalkanes or cycloalkanes can be used as the isocyanate-reactive plasticizer. Examples are butylene glycol, 1,6-dihydroxyoctane; 1,7-dihydroxyoctane; 1,10-dihydroxydecane; 1.12-dihydroksidodekaani; 2,2,2-trimethylol-lipentaani; pentaerythritol; 1,3,5-trihydroksipentaani; 2,4,6-trihydroxyhexane; neopentyl glycol (2,2-dimethyl-1,3-dihydroxypropane); 2,2,4-trimethyl-l, 3-pentaamdioli; 1,4-cyclohexanedimethanol, etc .; polyoxyalkylene glycol in which the alkylene moiety contains 2 to 4 carbon atoms, such as polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol having a molecular weight of up to 500; polyvalent materials with a repeating chain - CH2-CH (CH2OH2.7nf where n ranges from 1 to 10; polyamino compounds such as 1,4-diaminobutane; 1,6-diaminohexane; 1,8-diaminododecane; it should be noted that the amino compounds there must be primary or secondary amines with at least one reactive hydrogen, the substituent may be attached to nitrogen, the substituent may be an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group.

Suitable examples of mercapto compounds include: 1,4-dimercapto-pentane; 1,6-dimerkaptoheksaani; 1,8-dimercapto-octane; 1.10-dimercaptodecane; 1.12-dimerkaptododekaani.

Suitable examples of amido compounds that can be used include 1,4-diamidobutane; 1,6-diamidoheksaani; 1,8-diamido-octane; 1.10-diamidodecane; 1.12-diamiodododekaani. It should be noted that the hydrogen atom attached to the amido group may be replaced by an alkyl or hydroxyalkyl group, in which case it has at least one hydrogen atom to be replaced which can be reacted from the amido group.

9 62677

The most reactive isocyanite group should be protected, as mentioned above. The most common preservatives are phenols, alcohols, caprolactam, aldoximes and ketoximes. The most preferred preservative is ketoxime. Suitable ketoximes are those disclosed in U.S. Patent 3,583,943. Preferred ketoximes are dialkyl ketoximes such as dimethyl ketoxime, methylethyl ketoxime, methyl isobutyl ketoxime and diisobutyl ketoxime.

Manufacture of crosslinking agent

a) Isophorone diisocyanate + preservative - ** X

b) X + polyfunctional plasticizer - * Y

wherein X contains a protected isocyanate group and one free isocyanate group; and Y contains a protected isocyanate group and a group obtained by reaction with a plasticizer.

As can be seen, the plasticizer is a polyfunctional material that reacts with a diisocyanate. The preferred plasticizer that can be used is one which contains at least 4 carbon atoms and in which the functional groups have isocyanate reactivity and are separated by at least 1 carbon atom. Preferably, the plasticizer has at least 6 to about 20 carbon atoms.

The plasticizer itself may be a reaction product, such as an ester, obtained from the reaction of a polyhydroxyl material and an acid, its anhydride or dibasic acid. Suitable polyvalent substances are described by Y. Suitable acids, dibasic acids and their anhydrides may contain up to 12 carbon atoms, such as oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, cork acid, azelinic acid and sebacic acid. One preferred ester is that obtained by reacting neopentyl glycol and 2,2-dimethyl-3-hydroxypropionic acid and having the structure

HO-CH2-C (CH3) 2-CH2-0-C (O) -C (CH 3) 2 CH 2 OH

Other suitable polyvalent compounds that can react with the polyisocyanate include polyvalent hydantoin compounds having the structure 10 62677 r &.

R

wherein and R 1 may be the same or different groups and may be hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, hydroxyalkyl groups having 1 to 6 carbon atoms, phenyl groups and the like.

3 R and R may be the same or different groups and may be hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, hydroxyalkyl groups having 1 to 6 carbon atoms, polyoxyalkylene groups having 2 to 4 carbon atoms per alkylene group, and the terminal group is a hydroxy group; repeating units of the formula - 5 5 CH 2 -CH (CH 2 OH) -7-n where n ranges from 1 to 10, etc. It should be noted that the hydantoin materials must contain at least two hydroxyl groups. Normally, these compounds are prepared by reacting dimethylhydantoin (R and R are methyl groups and R and R are hydrogen atoms) with a suitable hydroxy-generating material such as epichlorohydrin, ethylene oxide, propylene oxide, butylene oxide and the like.

The reaction product of epichlorohydrin may require hydrolysis to remove chlorine groups. In general, "polyvalent hydantoin derivatives" can be said to contain the 5-membered basic ring structure 3-6 shown above (excluding R substituents) having at least two hydroxy groups in the molecule.

It has also been determined that the bis-hydantoin derivative, i.e. a suitable methylene-bis- (substituted hydantoin) hydroxy derivative can also be used.

5 6

In the preferred hydantoin, R and R are both methyl-3 4 groups and R 3a R are both -C 2 H 4 OH groups. In another preferred hydantoin, R and R are both methyl-3 4 groups and R and R are both -Cl 2 OH groups.

Since the final powder preparation should have a rapid cure, the preservative should be released at a suitable temperature, preferably above 121 ° C. Because the first-reacted -NCO group is the most reactive and is now unprotected (121 ° C), it can rapidly crosslink with the isocyanate-reactive groups in the polymerized resin.

Another distinct advantage of the crosslinking agent of the present invention is that it is very stable due to the protected isocyanate, especially when exposed to outdoor air. This is particularly important for a powder coating preparation in the sense that a better shelf life is obtained and the powder does not agglomerate during handling.

The crosslinking agent and the polymerized resin prepared according to the above methods can be used as a primer to be applied to a suitable substrate after dilution as a suitable organic solvent. However, in addition, the paint (solvent plus film former, i.e., polymerized resin + crosslinker) can be used to prepare powder paint particles according to the method described in U.S. Patent 3,737,401, Method of Making Powder Paint.

A preferred method of making the powder particles of this invention is to prepare the particles by the precipitation process of U.S. Patent 3,737,401. In this process, fine droplets are formed from the film former and the organic solvent of the film former. When the liquid paint is contacted with a second solvent which is not a solvent for the film former but is a two-way solvent (partially miscible) with the first solvent, droplets form. The powder particles precipitate when the first solvent is removed from the droplets by diluting them while in contact with the solvent into which the first solvent is miscible. The preferred solvent pair is an organic solvent (ketone) for the film former and water.

12 62677

Other components may be added to the liquid prior to the formation of powder particles, such as pigments, fillers, organic dyes and varnishes, plasticizers and spread control agents, catalysts to accelerate the cure rate, antistatic agents, etc. A preferred additional plasticizer that can be mixed with crosslinking agents is a reaction between a saturated aliphatic triol having up to 12 carbon atoms (about 2 parts by weight) and a long-chain monobasic fatty acid (having at least 5 carbon atoms of about 2 parts by weight), the reaction product of which is then reacted with an aromatic or saturated aliphatic anhydrous dibasic (about 1 part) to give a mixture with an excess, preferably 50% excess of hydroxyl groups. The hydroxyl groups of this plasticizer can react with the unprotected isocyanate groups of the crosslinker during curing of the powder.

It should further be noted that other soluble plasticizers may be added to supplement the film-forming components to allow them to react with excess unreacted, unprotected isocyanate groups. Therefore, these additives only need to have the ability to have isocyanate-reactive functionality (including groups with displaceable hydrogen atoms, as described above) and to give the resin their plasticizing properties.

Any of the above plasticizers can be used. Preferred substances include polyvalent substances such as cellulose derivatives (cellulose acetate, cellulose acetate-butyrate), alkane polyols, polyvalent lactones and lactams having 5-7 membered rings, polyvalent hydantoin materials and the like.

Calculated from the film-forming ingredients comprising a total of 100% by weight of the powder preparations of this invention can be described as follows: 62677 13 polymerized gauze 30-75% crosslinking agent with which the plasticizer has reacted 70-25% additional plasticizer 0-10%, preferably at least 1%

The powder preparation can also be presented for different reactive groups.

A. polymerized resin 0.7-1.5 isocyanate-reactive groups B. crosslinking agent 0.8-1.5 isocyanate groups C. plasticizer (before reaction with silicone) 0.8-1.1 isocyanate-reactive groups

Together, components B + c must have excess NCO groups in order to be reactive with the polymerized resin.

Now that the invention has been described above, other embodiments of the invention are set forth below. All temperatures are in ° C and all percentages are by weight unless otherwise indicated.

Example 1

An acrylic resin mixture was prepared by adding one part of acrylic acid, one part of ethyl hexyl acrylate, six parts of ethyl hexyl methacrylate, twenty parts of ethyl methacrylate, five parts of hydroxypropyl methacrylate to an organic ketone solvent; the solution was polymerized. with an azocatalyst at about 80 ° C.

The crosslinking agent was prepared by adding one part of isophorone diisocyanate, one part of methyl ethyl oxime to the organic ketone solvent until the reaction was completed. Half a portion of 1,6-hexanediol was then added until the reaction was complete. Dibutyltin oxide was added to complete the reaction.

A solution containing a 2: 1 polymerized acrylic resin and a crosslinking agent was then prepared. Carbon pigments 14 6267 7 were added in a ratio of 1 part pigment to 25 parts acrylic resin, and powder particles were prepared according to U.S. Patent 3,737,401 by mixing a film-forming solution and then adding it to a liquid mixture of water and ketone at which point droplets began to form. The solution was then added to substantial new volumes of water to effect precipitation of the powder by diluting the ketone from the droplets. The powder was then separated from the liquid by filtration, washing and drying.

Particle diameters ranged from 5 to 50 microns.

The purified steel plate was used as a substrate on which the particles were sprayed from the electrostatic. The film was cured to a dry, hard, adhesive, high gloss coating by drying the plate at about 163 ° C.

Example 2

Following the procedure of Example 1, an excess of isocyanate was used (50% excess) in the preparation of the crosslinking agent. Prior to precipitation, a second plasticizer (0.1 part per part acrylic resin) was added from the mixed medium. The second plasticizer was the reaction product of trimethylolpropane (2 parts), pelargonic acid (2 parts) and phthalic anhydride (1 part). The powder was formed in the same manner as in Example 1. The powder particles were electrostatically sprayed on a steel plate and then vulcanized by bringing the plate to a temperature of about 163 ° C. The film was hard and sticky and can be characterized as having a very glossy surface layer quality.

Example 3

The procedure of Example 2 was followed except that caprylic lactone diol (one part per ten parts of acrylic resin) was added before precipitation. Corresponding films were obtained on the surface of the steel.

Example 4 The procedure of Example 1 was used to prepare the resin and powder except that the following recipe was used to prepare the crosslinking agent: is 62677

Material Equivalent

Isophorone diisocyanate 7.6 ho-ch2-c (ch3) 2-ch2-o -C (O) 2.0

HO CH2 - (CH3) 2 -C

Trimethylolpropane 2.0

Methyl isobutyl ketoxime 3.64 The films prepared according to this example are substantially similar to the films of Example 1.

Example 5 The procedure of Example 1 was used to prepare the resin and powder except that the following recipe was used to prepare the crosslinking agent.

Material Equivalent

Isophorone diisocyanate 5.0 1,3- (2-hydroxyethyl) -5,5-dimethylhydantoin 2.5

Methyl isobutyl ketoxime 2.5 The films prepared according to this example are superior to the films prepared according to Example 1.