CA1237236A - Epoxy-maleate-phosphate copolymers - Google Patents
Epoxy-maleate-phosphate copolymersInfo
- Publication number
- CA1237236A CA1237236A CA000480906A CA480906A CA1237236A CA 1237236 A CA1237236 A CA 1237236A CA 000480906 A CA000480906 A CA 000480906A CA 480906 A CA480906 A CA 480906A CA 1237236 A CA1237236 A CA 1237236A
- Authority
- CA
- Canada
- Prior art keywords
- recited
- acid
- monoethylenically unsaturated
- copolymer
- polyepoxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F299/00—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers
- C08F299/02—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates
- C08F299/026—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from the reaction products of polyepoxides and unsaturated monocarboxylic acids, their anhydrides, halogenides or esters with low molecular weight
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/14—Polycondensates modified by chemical after-treatment
- C08G59/1405—Polycondensates modified by chemical after-treatment with inorganic compounds
- C08G59/1422—Polycondensates modified by chemical after-treatment with inorganic compounds containing phosphorus
Abstract
EPOXY-MALEATE-PHOSPHATE COPOLYMERS
ABSTRACT
There is disclosed solution copolymers of monoethylenically unsaturated monomers including a proportion of monoethylenically unsaturated carboxylic acid, with an oxirane-free epoxy acid ester phosphate having adducted onto the oxirane groups of a starting polyepoxide at least 10% thereof of ortho phosphoric acid as well as at least 0.5% by weight of a monoester of a saturated monohydric alcohol with a monoethylenically unsaturated dicarboxylic acid which resists homopolymerization, the remaining oxirane groups of the polyepoxide being esterified with monocarboxylic acid, etherified with monoalcohol or hydrolyzed with water. These copolymers can be neutralized with a volatile amine, especially ammonia and cured with aminoplast or phenoplast resins to provide coatings which cure to greater flexibility and better resistance to blushing on pasteurization exposure.
ABSTRACT
There is disclosed solution copolymers of monoethylenically unsaturated monomers including a proportion of monoethylenically unsaturated carboxylic acid, with an oxirane-free epoxy acid ester phosphate having adducted onto the oxirane groups of a starting polyepoxide at least 10% thereof of ortho phosphoric acid as well as at least 0.5% by weight of a monoester of a saturated monohydric alcohol with a monoethylenically unsaturated dicarboxylic acid which resists homopolymerization, the remaining oxirane groups of the polyepoxide being esterified with monocarboxylic acid, etherified with monoalcohol or hydrolyzed with water. These copolymers can be neutralized with a volatile amine, especially ammonia and cured with aminoplast or phenoplast resins to provide coatings which cure to greater flexibility and better resistance to blushing on pasteurization exposure.
Description
7~
EPOXY-MALEATE-PHOSPHATE COPOLYMERS
DESCRIPTION
Technical Field This invention relates to copolymers of monoethylenically unsaturated monomers with phosphate esters based on epoxy resins which have been reacted to consume all of the epoxy ~1,2-oxirane) functionality, so that the ester which is present during the copolymerization is not an epoxide.
10 Background Art Polyepoxide copolymers with monomers which include monoethylenically unsaturated carboxylic acids are known. These are produced by a graft polymerization process in the presence of the epoxy 15 functional compound and incorporated into aqueous coating compositions by reaction of the acid copolymer with a volatile base which is usually an amine, a term which includes ammonia. Aqueous coating compositions of the type described are in 20 commerce where they find use as interior sprays for sanitary cans. ~fforts to use the commercially available aqueous coatings as an end enamel have not been successful because these coatings lack the flexibility and pasteurization resistance needed for 25 end enamel use.
We have previously tried to improve these aqueous coatings by esterifying a portion of the polyepoxide with an unsaturated acid, such as monobutyl maleate, so that the subsequent 30 copolymerization would include copolymerization with the unsaturation in the ester group and thus provide a more intimate association between the copolymer molecules and the polyepoxide molecules. This work is set forth in various patents, U. S. Pat. No.
35 4,404,336 being illustrative. While this technology 3 7;~:~3~
provides a substalltial advance, the copolymers disclosed therein are best used with volatile amines other than ammonia, and their adhesion could be improved. Ihese are significant disadvantages.
It is desired to provide copolymers having improved properties~ arn-l to particularly provide copolymers which are more flexihle and more resistant to blushing when subjected to pas-teurizing conditions than the materials now in commerce. It is especially 10 desired to provide aa,ueous coathlgs in which the copolymer is solubilized ~iith ammonia at a higher solids content than was previously feasible since this lead ~o cost savings in the shipping of the product. Also, it is desired to lower the curing 15 temperature which is needed to thermoset the coating.
In a companion application, we have disclosed graft copolymers similar to those used herein and which do not include any maleate component. The copolymers of this invention contain 20 little grafting and cure to provide films possessing better film clarity and higher gloss in comparison with those in the said companion application.
Description of Invention In accordance with this invention, a 25 solution copolymer of monoethylenically unsaturated nonomers including a proportion of monoethylenically unsaturated carboxylic acid, is formed with an oxirane-free epoxy acid ester phosphate having adducted onto ~he oxirane groups of a starting 30 polyepoxide at least lO% thereof of ortho phosphoric acid as well as at least 0.5~ by weight of a monoester of a satura~ed monohydric alcohol with a monoethylenically unsaturated dicarboxylic acid which resists homopolymerization, the remaining oxirane 35 groups of said polyepoxide being esterified with 37;~3~
monocarboxylic acid, etherified with monoalcohol or hydrolyzed with water. The polyepoxide is preferably solid at room temperature (25~.) which is referred to herein as normally solid, and any residual epoxide functionality is destroyed either before or after the reaction with phosphoric acid. The phosphoric acid is monofunctional in its reaction with the oxirane groups of the polyepoxide, and this leaves two unreacted POH groups. The monoethylenically 10 unsaturated carboxylic acid is desirably used in an amount to provide -the copolymer with an acid number of from 20-150.
The oxirane-free epoxy maleate phosphate is copolymerized with the monoethylenic monomers in 15 solvent solution in the present of a free radical polymerization catalyst, which is preferably a peroxide used in an amount of at least about 2% of the monoethylenic monomers present. The result is a copolymer which includes little grafting and which is 20 primarily a copolymer with the maleic ester groups which are introduced by adduction. This product is easily solubilized in water with the aid of a volatile amine, preferably ammonia, and it is characterized by finer particle size than the aqueous 25 dispersions which were produced in our previously referred to companion application. This finer particle size may be the causative factor leading to the better film clarity and greater gloss which is achieved herein. These copolymers cure readily in 30 the presence of added aminoplast resin or phenoplast resin, and they are characterized by higher solids content in the aqueous medium, and better cure indicated by greater flexibility and better resistance to blushing on exposure to pasteurization 35 conditions. The added phosphoric acid provides a better and lower temperature cure than is possible without the addition of this acid.
The monoesters of a saturated monohydric alcohol with a monoethylenicaLly unsaturated dicarboxylic acid which resists homopolymerization can vary with the alcohol selected and the acid which is chosen. Cl-C18 alkanols, preferably C2-C8 alkanols are used. It is not desired to have the alcohol contain significant unsaturation because this 10 provides too many unsaturataed groups. Thus9 allyl alcohol leads to a tendency to gel. The preferred alcohol is a b~tanol, such as n-butanol or isobutanol, but ethanol, propanol, 2-ethoxy ethanol,
EPOXY-MALEATE-PHOSPHATE COPOLYMERS
DESCRIPTION
Technical Field This invention relates to copolymers of monoethylenically unsaturated monomers with phosphate esters based on epoxy resins which have been reacted to consume all of the epoxy ~1,2-oxirane) functionality, so that the ester which is present during the copolymerization is not an epoxide.
10 Background Art Polyepoxide copolymers with monomers which include monoethylenically unsaturated carboxylic acids are known. These are produced by a graft polymerization process in the presence of the epoxy 15 functional compound and incorporated into aqueous coating compositions by reaction of the acid copolymer with a volatile base which is usually an amine, a term which includes ammonia. Aqueous coating compositions of the type described are in 20 commerce where they find use as interior sprays for sanitary cans. ~fforts to use the commercially available aqueous coatings as an end enamel have not been successful because these coatings lack the flexibility and pasteurization resistance needed for 25 end enamel use.
We have previously tried to improve these aqueous coatings by esterifying a portion of the polyepoxide with an unsaturated acid, such as monobutyl maleate, so that the subsequent 30 copolymerization would include copolymerization with the unsaturation in the ester group and thus provide a more intimate association between the copolymer molecules and the polyepoxide molecules. This work is set forth in various patents, U. S. Pat. No.
35 4,404,336 being illustrative. While this technology 3 7;~:~3~
provides a substalltial advance, the copolymers disclosed therein are best used with volatile amines other than ammonia, and their adhesion could be improved. Ihese are significant disadvantages.
It is desired to provide copolymers having improved properties~ arn-l to particularly provide copolymers which are more flexihle and more resistant to blushing when subjected to pas-teurizing conditions than the materials now in commerce. It is especially 10 desired to provide aa,ueous coathlgs in which the copolymer is solubilized ~iith ammonia at a higher solids content than was previously feasible since this lead ~o cost savings in the shipping of the product. Also, it is desired to lower the curing 15 temperature which is needed to thermoset the coating.
In a companion application, we have disclosed graft copolymers similar to those used herein and which do not include any maleate component. The copolymers of this invention contain 20 little grafting and cure to provide films possessing better film clarity and higher gloss in comparison with those in the said companion application.
Description of Invention In accordance with this invention, a 25 solution copolymer of monoethylenically unsaturated nonomers including a proportion of monoethylenically unsaturated carboxylic acid, is formed with an oxirane-free epoxy acid ester phosphate having adducted onto ~he oxirane groups of a starting 30 polyepoxide at least lO% thereof of ortho phosphoric acid as well as at least 0.5~ by weight of a monoester of a satura~ed monohydric alcohol with a monoethylenically unsaturated dicarboxylic acid which resists homopolymerization, the remaining oxirane 35 groups of said polyepoxide being esterified with 37;~3~
monocarboxylic acid, etherified with monoalcohol or hydrolyzed with water. The polyepoxide is preferably solid at room temperature (25~.) which is referred to herein as normally solid, and any residual epoxide functionality is destroyed either before or after the reaction with phosphoric acid. The phosphoric acid is monofunctional in its reaction with the oxirane groups of the polyepoxide, and this leaves two unreacted POH groups. The monoethylenically 10 unsaturated carboxylic acid is desirably used in an amount to provide -the copolymer with an acid number of from 20-150.
The oxirane-free epoxy maleate phosphate is copolymerized with the monoethylenic monomers in 15 solvent solution in the present of a free radical polymerization catalyst, which is preferably a peroxide used in an amount of at least about 2% of the monoethylenic monomers present. The result is a copolymer which includes little grafting and which is 20 primarily a copolymer with the maleic ester groups which are introduced by adduction. This product is easily solubilized in water with the aid of a volatile amine, preferably ammonia, and it is characterized by finer particle size than the aqueous 25 dispersions which were produced in our previously referred to companion application. This finer particle size may be the causative factor leading to the better film clarity and greater gloss which is achieved herein. These copolymers cure readily in 30 the presence of added aminoplast resin or phenoplast resin, and they are characterized by higher solids content in the aqueous medium, and better cure indicated by greater flexibility and better resistance to blushing on exposure to pasteurization 35 conditions. The added phosphoric acid provides a better and lower temperature cure than is possible without the addition of this acid.
The monoesters of a saturated monohydric alcohol with a monoethylenicaLly unsaturated dicarboxylic acid which resists homopolymerization can vary with the alcohol selected and the acid which is chosen. Cl-C18 alkanols, preferably C2-C8 alkanols are used. It is not desired to have the alcohol contain significant unsaturation because this 10 provides too many unsaturataed groups. Thus9 allyl alcohol leads to a tendency to gel. The preferred alcohol is a b~tanol, such as n-butanol or isobutanol, but ethanol, propanol, 2-ethoxy ethanol,
2-ethylhexanol, and the like, are all useful, alone 15 or in combination.
Maleic acid, fumaric acid and itaconic acids will illustrate the unsaturated dicarboxylic acids which can be used. It is preferred to form the monoester from the acid in its anhydride form, but 20 this is a background feature herein, and is itself well known.
The maleic half esters are especially preferred and introduce considerable economy into the products oE this invention.
The polyepoxides used herein may be constituted by any resinous polyepoxide having a 1,2-epoxy functionality in excess of 1Ø The preferred materials have a l,2-epoxy functiona]ity in excess of 1.2 and sufficient molecular weight to be 30 solid in the absence of organic solvent at room temperature (25C.). This is ~ermed normally solid.
The most satisfactory polyepoxides are diglycidyl ethers of a bisphenol, especially those having a 1,2-epoxy equivalency of about 1.4 to about 2Ø
35 These polyepoxides are well known and commercially ~3~23Ç~
available, the bisphenol usually used being bisphenol A. While molecular weights of from about 350 to about 7,000 are useful, a molecular weight of from about 1,000 to about 5,000 is preferred. These weights are commonly obtained by calculation.
At least 10~, preferably at least 50~, of the oxiralle groups in the starting polyepoxide are to be esterified with phosphoric acid. The remaining oxirane groups may be consumed in any desired 10 fashion, preferably by esterification with a saturated monocarboxylic acid, like acetic acid or butyric acid, or by etherification with a saturated monohydric alcohol, like butanol or 2-ethylhexanol, or by hydrolysis with water. The consumption of the 15 remaining oxirane groups may be carried out either before or after reaction with phosphoric acid, though any reaction with water is preferably carried out after the reaction with phosphoric acid is complete.
The phosphoric acid which is primarily 20 contemplated is ortho phosphoric acid. However, if a P205-H2~ mixture ~hich is more concentrated than phosphoric acid is used, then subsequent hydrolysis with water will produce the same result as if ortho phosphoric acid had been used initially.
Complete consumption of the oxirane functionality prior to copolymerization is important. Unreacted oxirane functionality can introduce a measure of instability into coating compositions containing an aminoplast curing agent.
30 It is difficult to consume the oxirane functionality during copolymerization because the unsaturated acids do not esterify with oxirane functionality under most copolymerization conditions. In this invention, the oxirane functionality is gone before the 35 copolymerization is started.
~J3~7~3Çi The proportion o~ monoethylenically unsaturated monomers which may be copolymerized with the oxirane-free epoxy phospha~e may vary considerably, hut it is preferred to employ from 15%
to 70% of monoethylenic monomers, based on the weight of the copolymer, to provide the desired copolymer product. These monomers include monoethylenic carboxylic acid, such as methacrylic acid or fumaric acid, to provide an acid number of from 20-150, 10 preferably 50-120 in the final copolymer so that amine (preferably ammonia) and water can be added to provide a water dispersion which is either a solution or a colloidal di~persion.
The bulk of the monomers which are used (at 15 least about 50% by weight) are nonreactive, which indicates that, aside from their polymerizable monoethylenic unsaturation, they do not react under the conditions of polymerization and use which are contemplated. This normally means that there are no 20 functional groups except the single polymerizable ethylenic group. Styrene and vinyl toluene are particularly contemplated, though methyl acrylate, methyl methacrylate, ethyl acrylate, acrylonitrile and ~inyl acetate will further illustrate the useful 25 monoethylenically unsaturated monomers.
In the preferred systems, the only reactive monomer which is present is the monoethylenically unsaturated carboxylic acid. Monocarboxylic acids are useful, such as acrylic acid and methacrylic 30 acid. Polycarboxylic acids are also useful, such as maleic acid, and itaconic acid. Acid selection is a secondary aspect of this invention.
Other reactive monoethylenic monomers may also be present in an amount up to about 20% of the 35 total polymerizable monomers. These are illustrated ~3 ~:3~
by hydroxy monomers, such as 2-hydroxyethyl acrylate, amide monomers, such as acrylamide, N-methylol functional monomers, such as N-methylol acrylamide or methacrylamide, or an ether thereof, such as the butyl ether.
The copolymerization is itself conventional, ~eing carried out in organic solvent solution using a free radical generating polymerization catalyst, preferably at least about 2% of a peroxide catalyst, lO such as benzoyl peroxide. Peroxide catalysts are accepted for the production of coatings for use in contact with food, and are thus preferred. The solvent is preferably water miscible and used in minimal a~ount, so that the polymerization is usually 15 at 50% or higher solids content, preferably at least about 65%.
While aminoplast resins are preferably used for cure, such as hexamethoxymethyl melamine, one may also use phenoplast resins, such as an A-stage resol 20 or a phenol-formaldehyde condensate which is dispersible in the aqueous dispersions of this invention. This class of water soluble and water dispersible curing agents for curing hydroxy functional resins is a matter of common knowledge in 25 the art. Commercial products which may be used as curing agent are illustrated by Resimene X-273 ~and American Cyanamid product Cymel 37 ~ These various curing agents may be used in an amount up to about 40% of total resin solids, though their use is 30 desirably minimized so that amounts of from 5% to 20%
of total resin solids are preferred.
While ammonium hydroxide is preferred for so]ubilizing the acidic copolymeric product, organic amines, such as dimethyl ethanol amine, are also 35 useful, and both are embraced by the langua~e ~ T-~e ~Q,~
7Z '~
"volatile amine".
The resulting aqueous solutions cure to provide films characterized by superior resistance to èxtraction and they resist absorbing odor and flavor components of the foods and beverages which are packaged. They can be applied to any metal can interior, such as aluminum, stell and tirl-plated steel. Use as a can end enamel is also particularly contemplated because of the superior flexibility and 10 better pasteurization blush resistance which is obtained herein. Spray application and cure by baking at 400F. for 3 minutes are particularly contemplated. Films of about 0.2-0.3 mil are usually formed. Good adhesion is obtained on all of the 15 mentioned surfaces.
Throughout this application, all parts and proportions are by weight unless otherwise stated.
This invention is illustrated as follows.
Example 1 435 grams of a diglycidyl ether of bisphenol A having a molecular weight of about 435 (the Shell Company product Epon 82 ~may be used) is reacted with 185 grams of bisphenol A in 160 grams of 2-butoxy ethanol. The reaction is carried Ollt by heating to 25 140C. and allowing the temperature to rise to 170C., whereupon it is held at 170C. for 1 hour.
60 grams of maleic acid n-butanol half ester and 3.2 grams of 85% ortho phosphoric acid are then added and the mixture is held for 2 hours at 170C. and then 30 cooled to 140C. It is to be noted that the phosphoric acid reactant brings in 15~ of water with it, and the maleic half ester, the phosphoric acid and the water are sufficient to react with all of the oxirane groups in the diglycidyl ether. To insure 35 completion of the reaction and the consumption of all ~T~
~3~7~3~
the oxirane functionality, 1.0 gram of sodium carbonate is added, and the mixture is held at 140C.
for 1 hour. The sodium carbonate acts as an alkaline catalyst to encourage the esterification and hydrolysis reactions. The product is then cooled to 125C. and 200 grams of butanol are added to complete the preparation of the epoxy maleate phosphate.
At this point a mixture of Z05 grams ethyl acrylate, 60 grams methacrylic acid, and 75 grams lO styrene is prepared and 40 grams of cumene hydroperoxide is dissolved in 120 grams of butanol.
These two solutions are slowly and concurrently added to the oxirane free epoxy maleate phosphate sollltion over a two and one half hour period at 120C. to 15 125C. and the mixture is held at that temperature range for an additional hour. 7 grams of tertiary-butyl perbenzoate are then added and held at temperature ~or l hour, and then 7 more grams of the same perbenzoate are added and held at temperature 20 for one and one half hours to complete the copolymerization. The product is a copolymer which includes little grafting, and it provides a single phase resin product.
The product is cooled to 90C and 120 grams 25 of 28% aqueous ammonia is added over 30 minutes.
Then 1600 grams of deionized water is added to provide an aqueous dispersion having fine particle size and a solids content of 32% and an acid value of 47.
Upon reverse roll coat application on aluminum, steel and tin-plated steel panels in a thickness of0.25 mil and baking for 3 minutes in an oven maintained at 400F., good solvent resistant flexible coatings are obtained. These have be~ter 35 flexibility and better pasteurization blush 1~3~236 resistance than the epoxy graft copolymer aqueous coatings now in commerce and which are shipped at about 22~ solids content.
The cured films are clearer and of higher gloss than the maleate-free systems in our companion application, and they are more adherent that -the phosphate-free systems of our United States Patent No. 4,404,336.
It should also be observed that the presence of the phosphoric acid ester groups serves the further function of lowering the curing temperature. The prior epoxy graft copolymers are conventionally cured in ovens maintained at 425F. to 450F.
while a good cure can be obtained herein at temperatures as low as about 390F.
Maleic acid, fumaric acid and itaconic acids will illustrate the unsaturated dicarboxylic acids which can be used. It is preferred to form the monoester from the acid in its anhydride form, but 20 this is a background feature herein, and is itself well known.
The maleic half esters are especially preferred and introduce considerable economy into the products oE this invention.
The polyepoxides used herein may be constituted by any resinous polyepoxide having a 1,2-epoxy functionality in excess of 1Ø The preferred materials have a l,2-epoxy functiona]ity in excess of 1.2 and sufficient molecular weight to be 30 solid in the absence of organic solvent at room temperature (25C.). This is ~ermed normally solid.
The most satisfactory polyepoxides are diglycidyl ethers of a bisphenol, especially those having a 1,2-epoxy equivalency of about 1.4 to about 2Ø
35 These polyepoxides are well known and commercially ~3~23Ç~
available, the bisphenol usually used being bisphenol A. While molecular weights of from about 350 to about 7,000 are useful, a molecular weight of from about 1,000 to about 5,000 is preferred. These weights are commonly obtained by calculation.
At least 10~, preferably at least 50~, of the oxiralle groups in the starting polyepoxide are to be esterified with phosphoric acid. The remaining oxirane groups may be consumed in any desired 10 fashion, preferably by esterification with a saturated monocarboxylic acid, like acetic acid or butyric acid, or by etherification with a saturated monohydric alcohol, like butanol or 2-ethylhexanol, or by hydrolysis with water. The consumption of the 15 remaining oxirane groups may be carried out either before or after reaction with phosphoric acid, though any reaction with water is preferably carried out after the reaction with phosphoric acid is complete.
The phosphoric acid which is primarily 20 contemplated is ortho phosphoric acid. However, if a P205-H2~ mixture ~hich is more concentrated than phosphoric acid is used, then subsequent hydrolysis with water will produce the same result as if ortho phosphoric acid had been used initially.
Complete consumption of the oxirane functionality prior to copolymerization is important. Unreacted oxirane functionality can introduce a measure of instability into coating compositions containing an aminoplast curing agent.
30 It is difficult to consume the oxirane functionality during copolymerization because the unsaturated acids do not esterify with oxirane functionality under most copolymerization conditions. In this invention, the oxirane functionality is gone before the 35 copolymerization is started.
~J3~7~3Çi The proportion o~ monoethylenically unsaturated monomers which may be copolymerized with the oxirane-free epoxy phospha~e may vary considerably, hut it is preferred to employ from 15%
to 70% of monoethylenic monomers, based on the weight of the copolymer, to provide the desired copolymer product. These monomers include monoethylenic carboxylic acid, such as methacrylic acid or fumaric acid, to provide an acid number of from 20-150, 10 preferably 50-120 in the final copolymer so that amine (preferably ammonia) and water can be added to provide a water dispersion which is either a solution or a colloidal di~persion.
The bulk of the monomers which are used (at 15 least about 50% by weight) are nonreactive, which indicates that, aside from their polymerizable monoethylenic unsaturation, they do not react under the conditions of polymerization and use which are contemplated. This normally means that there are no 20 functional groups except the single polymerizable ethylenic group. Styrene and vinyl toluene are particularly contemplated, though methyl acrylate, methyl methacrylate, ethyl acrylate, acrylonitrile and ~inyl acetate will further illustrate the useful 25 monoethylenically unsaturated monomers.
In the preferred systems, the only reactive monomer which is present is the monoethylenically unsaturated carboxylic acid. Monocarboxylic acids are useful, such as acrylic acid and methacrylic 30 acid. Polycarboxylic acids are also useful, such as maleic acid, and itaconic acid. Acid selection is a secondary aspect of this invention.
Other reactive monoethylenic monomers may also be present in an amount up to about 20% of the 35 total polymerizable monomers. These are illustrated ~3 ~:3~
by hydroxy monomers, such as 2-hydroxyethyl acrylate, amide monomers, such as acrylamide, N-methylol functional monomers, such as N-methylol acrylamide or methacrylamide, or an ether thereof, such as the butyl ether.
The copolymerization is itself conventional, ~eing carried out in organic solvent solution using a free radical generating polymerization catalyst, preferably at least about 2% of a peroxide catalyst, lO such as benzoyl peroxide. Peroxide catalysts are accepted for the production of coatings for use in contact with food, and are thus preferred. The solvent is preferably water miscible and used in minimal a~ount, so that the polymerization is usually 15 at 50% or higher solids content, preferably at least about 65%.
While aminoplast resins are preferably used for cure, such as hexamethoxymethyl melamine, one may also use phenoplast resins, such as an A-stage resol 20 or a phenol-formaldehyde condensate which is dispersible in the aqueous dispersions of this invention. This class of water soluble and water dispersible curing agents for curing hydroxy functional resins is a matter of common knowledge in 25 the art. Commercial products which may be used as curing agent are illustrated by Resimene X-273 ~and American Cyanamid product Cymel 37 ~ These various curing agents may be used in an amount up to about 40% of total resin solids, though their use is 30 desirably minimized so that amounts of from 5% to 20%
of total resin solids are preferred.
While ammonium hydroxide is preferred for so]ubilizing the acidic copolymeric product, organic amines, such as dimethyl ethanol amine, are also 35 useful, and both are embraced by the langua~e ~ T-~e ~Q,~
7Z '~
"volatile amine".
The resulting aqueous solutions cure to provide films characterized by superior resistance to èxtraction and they resist absorbing odor and flavor components of the foods and beverages which are packaged. They can be applied to any metal can interior, such as aluminum, stell and tirl-plated steel. Use as a can end enamel is also particularly contemplated because of the superior flexibility and 10 better pasteurization blush resistance which is obtained herein. Spray application and cure by baking at 400F. for 3 minutes are particularly contemplated. Films of about 0.2-0.3 mil are usually formed. Good adhesion is obtained on all of the 15 mentioned surfaces.
Throughout this application, all parts and proportions are by weight unless otherwise stated.
This invention is illustrated as follows.
Example 1 435 grams of a diglycidyl ether of bisphenol A having a molecular weight of about 435 (the Shell Company product Epon 82 ~may be used) is reacted with 185 grams of bisphenol A in 160 grams of 2-butoxy ethanol. The reaction is carried Ollt by heating to 25 140C. and allowing the temperature to rise to 170C., whereupon it is held at 170C. for 1 hour.
60 grams of maleic acid n-butanol half ester and 3.2 grams of 85% ortho phosphoric acid are then added and the mixture is held for 2 hours at 170C. and then 30 cooled to 140C. It is to be noted that the phosphoric acid reactant brings in 15~ of water with it, and the maleic half ester, the phosphoric acid and the water are sufficient to react with all of the oxirane groups in the diglycidyl ether. To insure 35 completion of the reaction and the consumption of all ~T~
~3~7~3~
the oxirane functionality, 1.0 gram of sodium carbonate is added, and the mixture is held at 140C.
for 1 hour. The sodium carbonate acts as an alkaline catalyst to encourage the esterification and hydrolysis reactions. The product is then cooled to 125C. and 200 grams of butanol are added to complete the preparation of the epoxy maleate phosphate.
At this point a mixture of Z05 grams ethyl acrylate, 60 grams methacrylic acid, and 75 grams lO styrene is prepared and 40 grams of cumene hydroperoxide is dissolved in 120 grams of butanol.
These two solutions are slowly and concurrently added to the oxirane free epoxy maleate phosphate sollltion over a two and one half hour period at 120C. to 15 125C. and the mixture is held at that temperature range for an additional hour. 7 grams of tertiary-butyl perbenzoate are then added and held at temperature ~or l hour, and then 7 more grams of the same perbenzoate are added and held at temperature 20 for one and one half hours to complete the copolymerization. The product is a copolymer which includes little grafting, and it provides a single phase resin product.
The product is cooled to 90C and 120 grams 25 of 28% aqueous ammonia is added over 30 minutes.
Then 1600 grams of deionized water is added to provide an aqueous dispersion having fine particle size and a solids content of 32% and an acid value of 47.
Upon reverse roll coat application on aluminum, steel and tin-plated steel panels in a thickness of0.25 mil and baking for 3 minutes in an oven maintained at 400F., good solvent resistant flexible coatings are obtained. These have be~ter 35 flexibility and better pasteurization blush 1~3~236 resistance than the epoxy graft copolymer aqueous coatings now in commerce and which are shipped at about 22~ solids content.
The cured films are clearer and of higher gloss than the maleate-free systems in our companion application, and they are more adherent that -the phosphate-free systems of our United States Patent No. 4,404,336.
It should also be observed that the presence of the phosphoric acid ester groups serves the further function of lowering the curing temperature. The prior epoxy graft copolymers are conventionally cured in ovens maintained at 425F. to 450F.
while a good cure can be obtained herein at temperatures as low as about 390F.
Claims (17)
1. A solution copolymer of monoethylenically unsaturated monomers including a proportion of monoethylenically unsaturated carboxylic acid, with an oxirane-free epoxy acid ester phosphate having adducted onto the oxirane groups of a starting polyepoxide at least 10% thereof of ortho phosphoric acid as well as at least 0.5% by weight of a monoester of a saturated monohydric alcohol with a monoethylenically unsaturated dicarboxylic acid which resists homopolymerization, the remaining oxirane groups of said polyepoxide being esterified with monocarboxylic acid, etherified with monoalcohol or hydrolyzed with water.
2. A solution copolymer as recited in claim 1 in which ortho phosphoric acid is adducted onto at least 50% of the oxirane groups of the starting polyepoxide.
3. A solution copolymer as recited in claim 1 in which said polyepoxide is a diglycidyl ether of a bisphenol having a 1,2-epoxy equivalency in the range of 1.4 to 2.0 and a molecular weight in the range of 350 to 7,000.
4. A solution copolymer as recited in claim 1 in which said polyepoxide is normally solid.
5. A solution copolymer as recited in claim 2 in which said polyepoxide is a diglycidyl ether of a bisphenol having a 1,2-epoxy equivalency in the range of 1.4 to 2.0 and a molecular weight in the range of 1,000 to 5,000.
6. A solution copolymer as recited in claim 5 in which said bisphenol is bisphenol A.
7. A solution copolymer as recited in claim 1 in which said monoester is the reaction product of C2-C8 alkanol with maleic anhydride.
8. A solution copolymer as recited in claim 1 in which said monoester is monobutyl maleate.
9. A solution copolymer as recited in claim 1 in which monoethylenically unsaturated monomers are used in an amount of from 15% to 70%, based on the weight of the copolymer, and said monoethylenically unsaturated carboxylic acid being present in an amount to provide the copolymer with an acid number of from 20-150.
10. A solution copolymer as recited in claim 9 in which said monoethylenically unsaturated carboxylic acid is present in an amount to provide the copolymer with an acid number of from 50-120.
11. A solution copolymer as recited in claim 10 in which said monoethylenically unsaturated carboxylic acid is acrylic acid or methacrylic acid.
12. A solution copolymer as recited in claim 9 in which said monoethylenically unsaturated monomers comprise at least 50% of monomers in which the single ethylenically unsaturated group is the sole reactive group.
13. A solution copolymer as recited in claim 12 in which said monomers and said oxirane-free epoxy phosphate are copolymerized in water-miscible organic solvent at a solids content of at least 50%
in the presence of a peroxide polymerization catalyst in an amount of at least 2% of the weight of the monoethylenically unsaturated monomers present.
in the presence of a peroxide polymerization catalyst in an amount of at least 2% of the weight of the monoethylenically unsaturated monomers present.
14. An aqueous coating composition comprising the solution copolymer of claim 1 dispersed in water with the aid of a volatile amine.
15. An aqueous coating composition as recited in claim 14 in which said amine is ammonia.
16. An aqueous coating composition as recited in claim 15 in which said coating contains a curing agent selected from aminoplast resins and phenoplast resins.
17. An aqueous coating composition as recited in claim 16 in which hexamethoxymethyl melamine is used as the curing agent in an amount of from 5% to 20% of total resin solids.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/609,798 US4585814A (en) | 1984-05-14 | 1984-05-14 | Epoxy-maleate-phosphate copolymers |
| US609,798 | 1984-05-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1237236A true CA1237236A (en) | 1988-05-24 |
Family
ID=24442377
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000480906A Expired CA1237236A (en) | 1984-05-14 | 1985-05-07 | Epoxy-maleate-phosphate copolymers |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4585814A (en) |
| EP (1) | EP0164589B1 (en) |
| JP (1) | JPS60245617A (en) |
| CA (1) | CA1237236A (en) |
| DE (1) | DE3572181D1 (en) |
| MX (1) | MX163710B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4692484A (en) * | 1985-09-25 | 1987-09-08 | Desoto, Inc. | Epoxy-phosphate/phenolic electrocoating compositions |
| DE3709270A1 (en) * | 1987-03-20 | 1988-09-29 | Herberts Gmbh | METHOD FOR FORMING SHEETS IN THE PRESENCE OF A COOLANT AND LUBRICANT |
| DE4327493A1 (en) * | 1993-08-16 | 1995-02-23 | Hoechst Ag | Aqueous, modified epoxy resin dispersions |
| BRPI0408909B1 (en) | 2003-04-02 | 2016-08-02 | Valspar Sourcing Inc | method for forming a dispersion, composition, method for coating an article, and, article |
| EP1819789B1 (en) | 2004-10-20 | 2011-06-15 | Valspar Sourcing, Inc. | Coating compositions for cans and methods of coating |
| EP2416962B1 (en) | 2009-04-09 | 2016-08-10 | Valspar Sourcing, Inc. | Polymer having unsaturated cycloaliphatic functionality and coating compositions formed therefrom |
| US8486574B2 (en) * | 2009-07-14 | 2013-07-16 | Ford Global Technologies, Llc | Method and system for power control in an automotive vehicle |
| EP3208289A1 (en) | 2009-07-17 | 2017-08-23 | Valspar Sourcing, Inc. | Coating composition and articles coated therewith |
| US8754614B2 (en) * | 2009-07-17 | 2014-06-17 | Tesla Motors, Inc. | Fast charging of battery using adjustable voltage control |
| BR112012006030A2 (en) | 2009-09-18 | 2016-03-22 | Valspar Sourcing Inc | method coated article and composition |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3574794A (en) * | 1968-01-22 | 1971-04-13 | Dow Chemical Co | Acrylic or methacrylic esters of hydroxyalkyl phosphate esters and process for making same |
| US3524903A (en) * | 1968-01-22 | 1970-08-18 | Dow Chemical Co | Flame-retardant vinyl ester containing alkyl hydrogen phosphate resin and a halogenated epoxide resin |
| DE2442101A1 (en) * | 1974-09-03 | 1976-03-11 | Bayer Ag | PHOSPHORUS AND, IF APPLICABLE, NITROGEN CONTAINING POLYMERS |
| US4308185A (en) * | 1976-05-11 | 1981-12-29 | Scm Corporation | Graft polymer compositions of terminated epoxy resin, processes for making and using same, and substrates coated therewith |
| US4294737A (en) * | 1979-12-28 | 1981-10-13 | Desoto, Inc. | Water soluble epoxy ester copolymers for interior can use |
| US4434278A (en) * | 1982-09-27 | 1984-02-28 | Celanese Corporation | Phosphate esters of acrylated epoxides |
-
1984
- 1984-05-14 US US06/609,798 patent/US4585814A/en not_active Expired - Fee Related
-
1985
- 1985-05-07 CA CA000480906A patent/CA1237236A/en not_active Expired
- 1985-05-11 DE DE8585105806T patent/DE3572181D1/en not_active Expired
- 1985-05-11 EP EP85105806A patent/EP0164589B1/en not_active Expired
- 1985-05-13 MX MX205279A patent/MX163710B/en unknown
- 1985-05-13 JP JP60101173A patent/JPS60245617A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US4585814A (en) | 1986-04-29 |
| EP0164589B1 (en) | 1989-08-09 |
| EP0164589A2 (en) | 1985-12-18 |
| JPS60245617A (en) | 1985-12-05 |
| EP0164589A3 (en) | 1987-03-11 |
| DE3572181D1 (en) | 1989-09-14 |
| MX163710B (en) | 1992-06-15 |
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