CA1102465A - Protective coating for metal articles - Google Patents

Protective coating for metal articles

Info

Publication number
CA1102465A
CA1102465A CA 283467 CA283467A CA1102465A CA 1102465 A CA1102465 A CA 1102465A CA 283467 CA283467 CA 283467 CA 283467 A CA283467 A CA 283467A CA 1102465 A CA1102465 A CA 1102465A
Authority
CA
Grant status
Grant
Patent type
Prior art keywords
acrylate
stage
methacrylate
ethyl
monomers
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
Application number
CA 283467
Other languages
French (fr)
Inventor
Andreas Lindert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Whittaker Corp
Original Assignee
Whittaker Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Grant date

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F265/00Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
    • C08F265/04Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F257/00Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00
    • C08F257/02Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00 on to polymers of styrene or alkyl-substituted styrenes
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F291/00Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to more than one of the groups C08F251/00 - C08F289/00
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; MISCELLANEOUS COMPOSITIONS; MISCELLANEOUS APPLICATIONS OF MATERIALS
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D151/00Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers
    • C09D151/003Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds

Abstract

Abstract of the Disclosure - This invention relates to a novel coating to be used for the lining of the interior of food, beer and beverage cans. The coating is prepared by emulsion polymerization by a two step process in which the ethylenically unsaturated carboxylic acid monomers are copolymerized in the presence of initiators to form a seed latex in the first stage; subsequently, the seed latex is neutralized with base, and the pH sensitive monomers are copolymerized in the second stage, which comprises from 68 to 90% by weight of the total monomer composition. The composition and rheology of the polymer result in a coating with excellent film properties and good application characteristics for interior can coatings.

- i -

Description

~Z~5 ., ~ This inv0ntion relates to the polymerization of pH sensitive and ethylenically unsaturated carboxylic acid monomers into ~he same latex system. More specifically this invention relates ~o coatings for interior can llnings, a process o forming said coatings and articles having said coatings, notably beverage containersO
Coatings used for interior can linings have been compcsed mostl~ o~ epoxy and polyvinyl chlor;de copolymers.
The can linlngs for food, beer and general beverage containers presently in use are applied from organic solvents which con-tribute to air pollution of the surrounding communities. In oxder to meet local and federal pollution regulations, expen-sive and energy~con~sum~ng incinerators mus~ be installed to combust the solvents emitted from the present can coatings. In an attempt to save energy and c~rcumvent the purchase of costly incinerators, considerable effort has been expende~ by coatings manufacturers to develop water-borne coatings which meet the physical performance characteristics required for interior can coatings and still remain within the federal air pollution guide-lines~ At present,~United States government regulations allow 20% organic solvent by volume in the volatile phase~
The principal aspect of the present invention is a water-borne interior can coating which possesses excellent physical properties, meets or exceeds present air pollution limitation, and which is prepared by the method of emulsion polymerization.

24~i BRIEF DESCI~IPI'ION OF THE INVEN-ION

The em~lsion polymers prepared by the procedure of the present invention possess superior performance and spray application properties when compared to water-borne polymers synthesized by standard solution and emulsion polymerization techniques. These properties are accomplished by polymerizing the monomers by a two step process in which the unsaturated carboxylic acid and other f mctional monomers are incorporated into the interpolymer in the first stage of the polymerization for the purpose of pH
control of the reaction, adhesion and emulsion stability.
According to the present invention; there is provided a latex of a two-stage interpolymer exhibiting a glass transition temperature of -6C. to 50C. and comprising: (a) lO to 35% of a first stage seed latex comprising the following reactants in percent by weight; 15-60% of an aromatic vinyl monomer; 25-50% of acrylate ester monomers selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate, isobutyl acrylate or methacrylate, and 2-ethyl hexyl acrylate; 5-30% of an unsaturated carboxylic acid monomer selected from the group consisting of acrylic or methacrylic acid, itaconic acid, maleic or fumaric acid and their half esters; and; 1-25% of polar monomers selected from the group consisting of hydroxy ethyl or propyl acrylate or methacrylate, acrylamide methacrylamide, acrylonitrile, methacrylonitrile, t-butyl-amino ethyl acrylate or methacrylate, dimethyl amino ethyl acrylate and methacrylate; and (b) 65 to 90% of a second stage polymer interpolymerized in the presence of the first stage seed latex comprising the following reactants in percent by weight; 0-97% of an aromatic vinyl monomer; 3-30% of a functional monomer selected from the group of N-Methylol acrylamide or methacrylamide and 1 to 6 carbon containing alkoxy ethers of the same; and ; 0-97% acrylate ester monomers selected from a group including methyl methacrylate, N-butyl acrylate or methacrylate, isobutyl acrylate or methacrylate and 2-ethyl hexyl acrylate.
In another aspect, the invention provides a process of forming a latex of a t~o-stage interpolymer of pH sensitive monomers comprising a first stage of polymerizing in an aqueous emulsion in the presence of an initiator:

g65 15-60% of an aromatic vinyl monomer; 25-50% o acrylate ester monomers selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate and 2-ethyl hexyl acrylate; 5-30% of an unsaturated carboxylic acid monomer selected from the group consisting of acrylic or methacrylic acid, itaconic acid, maleic or fumaric acid and their half esters; and; 1-25% of polar monomers selected from the group consisting of hydroxy ethyl or propyl acrylate or methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, t-butyl amino ethyl acrylate or methacry-late, dimethyl amino ethyl acrylate and methacrylate to thereby form a first stage polymer latex; neutralizin~ said first stage polymer latex to a pH of from 6 to 10 with a base, subsequently incorporating into said Eirst stage polymer latex, and polymerizing in an aqueous emulsion in the presence of a radical initiator, a mixture monomer components to form, in the latex product, a second s~age polymer comprising: 0-97% of an aromatic vinyl monomer; 3-30%
of a functional monomer selected from the group consisting of N-Methylol acrylamide, and alkoxy ether derivatives thereof; and; 0-~7% of at least one acrylate ester selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate, iso-butyl acrylate or metha-crylate and 2-ethyl hexyl acrylate; wherein said second stage polymer is formed in a reaction medium comprising: 70-100% deioni~ed water; and; 0-30% of an organic solvent or mixture thereof comprising ketones, hydrocarbons, esters, long chain aliphatic alcohols and glycol ethers.
In a preferred embodiment the invention provides a coating com-prising the latex hereinbefore defined and an organic solvent. Thus, the first stage of the reaction comprises from 10 to 35% by weight of the total monomers and is neutralized to a pH of from 6 to 10 before the second stage of the reaction is carried out. During the second stage, pH sensitive and reactive functional monomers such as n-Methylol acrylamide9 and isobutoxy methylacrylamide, as well as other ethylenically unsaturated monomers, are copolymeri~ed in~o ~he initial first stage "seed" latex. It is of advantage to incorporate functional reactive monomers and a N-Methylol acrylamide and its ether derivatives into the interpolymers to provide crosslinking of the film into a tough, insoluble and chemically resistant coating.

- 2a -Mhen incorporating pH sensitive monomers such as N-Methylol acrylamide into an emulsion polymer, inorganic buffering agents are employed to moderate the pH of the system. The buffering agents, as well as the levels of surfactants conventionally used in polymerization, interfere with the final film properties. ln particular, adhesion, water and beverage - 2b -spotting and the barxier properties to iron ion migration are - effected. By the use of the two step polymerization processof the present invention, the inorganic buffering agents and much of the emulsifiers can be eliminated from the reaction.

DETAILED DESCRIP~I~N
In the present invention, a water-borne interior can coating is provided. The coating is prepared by emulsion polymerization without the formation of coagulation of the latex, in the presence of low levels of emulsifiers. The latex is 1 also prepared without the use of water sensitive inorganic ' buffering agents. These aspects of the invention are accomplished by preparing the latex in a two stage process in which the first stage contains most of the ethylenlcally unsaturated carboxylic I! acid monomer. The unsaturated acid in the first stage is i incorporated by copolymerization with vinyl monomers such as ! vinyl aromatic monomers and acrylic or methacrylic acid esters.
¦ For an interior can coating, the first stage "seed"
¦l latex exhibits the following composition by weight:
¦~ 15 to 60 percent of an aromatic viny~ monomer. ~
25 - 50% of acrylate ester monomers selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate and 2-ethyl hexyl acrylate.
5 - 30% of an unsaturated carboxylic acid monomer selected from the group consisting of acrylic or methacrylic acid, itaconic acid, maleic -or fumaric acld and their half esters.

_ 3 _ 11~2465 1 - 25~ of polar monomers selected from the group consisting o hydroxy ethyl or propyl acrylate of methacrylate~ acrylamide, methacrylamide, acrylonitrile r methacrylonitrile, t-butyl amino ethyl acrylate or methacrylate, dimethyl amino ethyl acrylate and methacrylate.
I .
The amount and kind of initiator used can be varied depending on the particular polymerization desired. Any compound 1 which supplies a source of free radicals such as peroxides, ii hydroperoxides, perbenzoates, and persulfates can be employed.
i If a persulfate is used, ammonium persulfate is preferred since ik contains a fugitive cation that will not interfere with the I final film properties. The polymerization in bo~h the first and second stages of this present invention can be initiated by either 15 ¦I the thermal decomposition of the free radical initiators or by a redox system. The amount of initiator normally used is from .2 ~i to 1%, although the reaction can adequately be conducted with I higher and lower amounts~
l The polymerization c2n be carr-ed out at a t~mperature of from 50~C to 100C over a 6 to 20 hour period. However~ ¦
~' in practice, the temperature of the overall reaction changes from 60C to BSC over a 10 hour perlod.
The first stage copolymer latex comprises from 10~ ¦
l to 35% o the total polymer composition and is formed by I polymerizing said monomers in an aqueous medium in the presence 1 of emulsifiers and radical initiating compounds.

', I

I _ 4 _ : !

l~ Z4~5 ; After the fi-rst stage of the reaction is completed and before the second stage of the reaction can begin, the initial seed latex must be neutralized with base. The bases used in this l~process are those which are reactive with the carhoxylic acid S ~group on the seed polymer to form the corresponding salts.
Suitable bases are monovalent inorganic and organic bases.
~Examples, o~ basesr one or more of which may be employed in the process, are ammonium hydroxide (which may be provided by the ~ addition of ammonia to the aqueous reaction mixture), water I soluble alkali metal hydroxides such as sodium and potassium ~hydroxide, primary, secondary and tertiary amines in which the groups attached to the amino nitrogen atom are cyclic and acyclic alkyl, hydroxyalkyl and alkyl ether groups, e.g~, ethylamine, I diethylamine, triethylamine, dimethylamine, trimethylamine, ¦I N, Nl N , N - tetramethyl methylene diamine, N-hexylamine, ¦, dimethyl ethanolamine, N-dimethyl isopropanolamine and morpholine l! and quaternary ammonium bases such as benzyl trimethyl ammonium hydroxide and dodeoxytrimethyl ammonium hydroxide.
i Ammonia or organic bases are normally preferred in I order to reduce -later spotting of the final film. The pH of the system can readily be adjusted from 6 to 10 pH units Dy neutral-izing the polymer in such a manner.
In the second stage of the polymerization, a pH
1 sensitive compound can be incorporated into the seed latex.
! The N-methylol derivates as well as N-methylol ether derivatives of acrylamide and methacrylamide can be easily incorporated into the second stage of the present invention. The reactive function-al monomers are copolymerized with vinyl monomers and the polymer 110~65 strUCtULe of the second stage reaction can comprise the following composition:
; 0 - 79~ of an aromatic vinyl monomer, preferably styrene.
3 - 30% of a functional monomer such as N-Methylol acrylamide or its alkoxy ether derivakes such as isobutoxy methyl acrylamide.
0 - 97% acrylate esters selec~ed from a group including methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate, iso-butyl acrylate or methacrylate and 2-ethyl hexyl acrylate.
; The second stage react~on can be performed in the i presence of organic solvent without reduction of the yield Il of the reaction. The composition of the reaction medium in ; I the second stage can be composed o~:
¦ 30 - 100% deionized water 0 - 30% of an organic solvent ox mixture thexeof comprising ketones, hyarocarbons, esters, l long chain aliphatic alcohols and glycol ¦ ethers. -¦ In the finished coating, from 5% to 30% organic I solvent is desirable for good spray application, improved wetting li of the interior can substrate and good coalescence of the film Il upon application. If the organic solvent is added before or during polymerization of the second stage r~action, lower vis-cosities of the final co~ting are obtained. It is therefor-,. jl - .

ll~}Z~65 Il of advantage to polymerize the second stage reaction in a ¦I solvent-water blend. The final viscosities of the coating obtained by this technique will be ~ - 4 times lower than if ,I the polymerization were conducted in deionized water and the S 1~ solvent post-added after completion of the radical polymeriza-I! tion.
The second stage can comprise from 65% to 90~ of the total monomer composition. Although the polymerization process Il can be conducted in a number of different techniques commonly 1l known to those versed in the art, it is preferable to add the ¦I monomers with stirring to the neutralized first stage and then initiate the system by the use of radical generating compounds.
In practice, a hydroperoxide is used in the presence of a reducing ~ agent such as ascorbic acid, isoascorbic acid, glucose, fructose, j, dihydroxyacetone, hydrazine,~sodium formaldehyde sulfoxa;late, -polyamines and the like. A small trace of a complexed transition metal ion catalyst is also employed. The second stage of the , reaction can~be conducted at 40C to 100C depending on the li polymeric properties desired and the time for complete conversion ¦
I preferredO
¦ Emulsions used in the synthesis of the above polymers ¦ include both nonionic and anionic surfactants and their mixtures commonly employed for such purposes. In the first stage of the 1, reaction from .2 to 2.5~ surfactant based on monomers in the first stage may be employed. The stability of the second stage and the amount of emulsifier requlred for stabilization depends on the composition of the first stage of the reaction. When high levels ~ 5 ~of functional monomers such as acrylic acid, acrylamide or I hydroxy ethyl acrylate are employed in the first stage '~seed"
I I latex the surfactant can be reduced or eliminated in the second I stage of the reaction.
The advantages and utilîty of this invention are demonstrated below in the following examples. The examples are given only by way of illustration of the invention and not by limitation. All par~s are expressed by weight unless otherwise stated.
Example 1 ; ~ In accordance with the method stated above, the polymer coating was prepared in a two step process.
I ¦l (A) First-Stage of Reaction - An interpolymer of -the following ¦ composition was prepaxed:
Styrene ~ 26.0 Ethyl Hexyl Acrylate 32.8 Acrylic Acia 7.7 ~1 Hydroxy Ethyl Acrylate 4c4 Methyl Methacrylate 29.1 Deionized Wa~er 150 (NH4)~2S208 Ammonium Salt of Sulfate Nonylpkenoxy poly (ethyleneoxyl) ethanol 2.5 ~ The ammonium persulfate and deionized water were deaerated under ' a nitrogen stream and heated to 75C. The emulsifier was sub-i sequently added. 10~ of the monomer mixture was added and the ll~ remaining monomer was added over a 3 hour period. The reaction ¦~ was then heated to 85C and held for one hour to complete 1¦ polymerization~ Yield was 99% to 100%~ viscosity 15 seconds ~4 Ford cup and pH = 2.1.

.... , ~
.

2~65 (B) Second Stage - The following interpolymer composition is prepared:
1) The resin of Example 1 Part A 250 (40% solids~
2) Styrene 160 Ethyle Hexyl Acrylate160 Ethyl Acrylate 32 Isobutoxy Methylacrylamide 48

3) Deionized Water 755.0 Ascorbic Acid 2.0 Dimethyl ethanol 13.0 Amine FeSO4 Trace

4) t-Butyl Hydroperoxide 2.0 Deionized Water 122 . 2-Butoxy ethanol 122 250 parts of Resin A (1) is diluted with Part (3) and deaerated ¦l and the monomer mixture added ~2) L The reaction mixture is then li heated to 60C and one-half of the initiator-solvent mixture ! added o~er 15 minutes. The temperature increases to 75C and lS held at 75C throughout the reaction. The remaining initiator solvent mixture is added over 1 hour. Total reaction time is~
4 hours. Solids 30%, pH 8.4 J and viscosi~y is 30 seconds #4 ~ord cup. ~ I
~, Example 2 j . , . _ ¦¦ 1) The resin of ~xample 1 I Part A 172.6 Dimethy~ ethanolamine8.0 Ascorbic Acid 1.2 Fe Citrate Trace 2) Styrene 119.4 Ethyl Hexyl Acrylate90.0 Methyl Methacrylate126.9 . Isobutoxymethylacrylamide 53.0 3) 2-Butoxy ethanol 5 Cu~l~ne hydroperoxide 5 _~

., . .
.

-~

~L~QZ~6~

Part 1 was added to the reaction flask and heated to 60C. Then ~ Part (2) monomer mixture was added. The reaction was initiated Il by the addition of one-half of Part 3. The remainder of Part 3 ~ was added over one hour. Total reaction time three hours~
j~ Viscosity 14 seconds r pH a 8 ~1 and solids 34~O
¦¦ Although this invention has been illustrated by reference to specific embodiments, modifications thereof which ¦ are clearly within the scope of the invention will be apparent Ii to those skilled in the art.
ll The coating prepared by the methods stated above are 1~ ideally suited for interior of containers. The coatings can be ¦I applied by both air and airless spray equipment and when tested Il against a commercially used vinyl chloride copolymer, the coatings li of the presen~ invention show excellent performance characteris-j' tics. The standard tests conducted on these coatings are I ~I summarized belowa 1) Adhesion ¦¦ The coatings were applied to tin free steel, tin plate, ¦¦ treated and untreated aluminum, blac]~ plate as well as ¦¦ commercialiy used can coating organic basecoats. The ¦¦ materials were coated at approximately 5 mg/sq. inO and ¦' baked at 320F for 5 minutes~ The cured coatings were scored with a knife edge and the scored area covered with ill Scotch Tape (3M Corporation3~which was removed. The ¦~ coating was then examined for removal of material proximate ¦, to the scored area by the Scotch Tape. The amount of !l coating material removed by the Scotch Tape is indicative I of coating adhesion.
I
~ ~-10- 1 1, !

~2~6~;

2) Pasteurization The coating substrate is placed in beer having a temperature of 160F for one-half hour. The blush resistance of the coating is measured by the degree of milkiness or less of gloss o the coating.
3) Flavor Test Aluminum foil is coated on both sides with the subject coat}n~. The coating weight is approximately 200 mg and l the total area exposed to the beer is 40 sq. inches. The ¦! coated aluminum foil is placed in a 12 oz. bottle of beer ¦1 and sealed tightly~ The bottles are stored for a period jl of time at room temperature, chilled in a refrigerator overnight and tasted by a trained flavor panel. The coatings~
are compared with a co~mercial control for any flavor or odor ,, which they may lmpart to the beer.
l 4) Turbidity Test I ¦~ The test measures any change in the clarity of the beer ~i which may be imparted by the coating variable. The test is 1 conducted by coating A0 sq. in. o~ aluminum foil with 200 mg.
1 of the ~est coating and baking the ~oating at ~20F for l S minutes. The coated foil is then placed in a ~2 oz. bottlei ¦~ of beer, tightly seale~ and stored at an elevated temperature for a predetermined period of time. The turbldity is Il measured using a Hach Turbidity Meter and is expressed in 11 Forma~in Turbidity Units (FTU). A value of IS - 30 FTU
is normal for an acceptable bottle of beer.
! I

!

.

ILQZ~5 The coatings of the present invention pass or exceed all of the above tests standardly employed in the evaluation of interior can liners and are summarized in the table below.

TABLE I
PHY5ICAL I'EST COMPARISON .

Turbidity 3 Weeks Flavor Tin Epoxy Blush Coating @ 100F_ Test TFS Plate Phenolic Resi~tan~e Vinyl Control 23 FTU Pass Poor Poor Good Good Example 1 21 FTU Pass Good Good Good Good Example 2 24 FTU Pass Good ~ Good Good Good , . .

.
. : .
,

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A latex of a two-stage interpolymer exhibiting a glass transition temperature of -6°C. to 50°C. and comprising:
(a) 10 to 35% of a first stage seed latex comprising the following reactants in percent by weight;
15-60% of an aromatic vinyl monomer;
25-50% of acrylate ester monomers selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate, isobutyl acrylate or methacrylate, and 2-ethyl hexyl acrylate;
5-30% of an unsaturated carboxylic acid monomer selected from the group consisting of acrylic or methacrylic acid, itaconic acid, maleic or fumaric acid and their half esters; and 1-25% of polar monomers selected from the group consisting of hydroxy ethyl or propyl acrylate or methacrylate, acrylamide methacrylamide, acrylonitrile, methacrylonitrile, t-butyl-ammo ethyl acrylate or methacrylate, dimethyl amino ethyl acrylate and methacrylate; and (b) 65 to 90% of a second stage polymer interpolymerized in the presence of the first stage seed latex comprising the following reactants in percent by weight;
0-97% of an aromatic vinyl monomer;
3-30% of a functional monomer selected from the group of N-Methylol acrylamide or methacrylamide and 1 to 6 carbon containing alkoxy ethers of the same; and 0-97% acrylate ester monomers selected from a group including methyl methacrylate, N-butyl acrylate or methacrylate, isobutyl acrylate or metha-crylate and 2-ethyl hexyl acrylate.
2. A process of forming a latex of a two-stage interpolymer of pH
sensitive monomers comprising a first stage of polymerizing in an aqueous emulsion in the presence of an initiator;
15-60% of an aromatic vinyl monomer;

25-50% of acrylate ester monomers selected from a group consisting of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate and 2-ethyl hexyl acrylate;
5-30% of an unsaturated carboxylic acid monomer selected from the group consisting of acrylic or methacrylic acid, itaconic acid, maleic or fumaric acid and their half esters; and 1-25% of polar monomers selected from the group consisting of hydroxy ethyl or propyl acrylate or methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, t-butyl amino ethyl acrylate or methacrylate, dimethyl amino ethyl acrylate and methacrylate to thereby form a first stage polymer latex; neutralizing said first stage polymer latex to a pH of from 6 to 10 with a base, subsequently incorporating into said first stage polymer latex, and polymerizing in an aqueous emulsion in the presence of a radical initiator, a mixture of monomer components to form, in the latex product, a second stage polymer comprising:
0-97% of an aromatic vinyl monomer;
3-30% of a functional monomer selected from the group consisting of N-Methylol acrylamide, and alkoxy ether derivatives thereof; and 0-97% of at least one acrylate ester selected from a group consist-ing of methyl methacrylate, ethyl acrylate, n-butyl acrylate or methacrylate, iso-butyl acrylate or methacrylate and 2-ethyl hexyl acrylate;
wherein said second stage polymer is formed in a reaction medium comprising:
70-100% deionized water; and 0-30% of an organic solvent or mixture thereof comprising ketones, hydrocarbons, esters, long chain aliphatic alcohols and glycol ethers.
3. A process according to claim 2 for forming an interpolymer wherein said second stage is polymerized in the absence of buffering agents.
4. A two stage polymerization process of claim 2 in which a solvent is incorporated during the polymerization of the second stage and is selected from the group consisting of ketones, hydrocarbons, esters, long chain aliphatic alcohols and glycol ethers.
5. A process according to claim 3 wherein said monomers are polymerized by the thermal decomposition of free radical initiators selected from the group consisting of peroxides, azobisisobutyronitrile, perbenzoates, and hydroperoxides or by a redox system in both the first and second stages of the reaction.
6. A process according to claim 3 in which a nonionic and/or anionic emulsifier surfactant is used.
7. A coating which comprises the latex according to claim 1 and an organic solvent.
8. A method of coating a metal container, which comprises applying the coating preparation of claim 7 to the interior surface of said metal container.
CA 283467 1976-08-26 1977-07-25 Protective coating for metal articles Expired CA1102465A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US71760276 true 1976-08-26 1976-08-26
US717,602 1976-08-26

Publications (1)

Publication Number Publication Date
CA1102465A true CA1102465A (en) 1981-06-02

Family

ID=24882705

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 283467 Expired CA1102465A (en) 1976-08-26 1977-07-25 Protective coating for metal articles

Country Status (3)

Country Link
JP (1) JPS5328687A (en)
CA (1) CA1102465A (en)
GB (1) GB1555868A (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6160225B2 (en) * 1978-08-23 1986-12-19 Hitachi Ltd
US4469825A (en) * 1983-03-09 1984-09-04 Rohm And Haas Company Sequential heteropolymer dispersion and a particulate material obtainable therefrom, useful in coating compositions as an opacifying agent
FI853227L (en) * 1984-08-29 1986-03-01 Nat Starch Chem Corp Foer metalliserat Papper avsedd vattenhaltig basbelaeggning utan ytaktiva Medel.
JPH031321B2 (en) * 1985-05-02 1991-01-10 Asahi Chemical Ind
DE3543361A1 (en) * 1985-12-07 1987-06-11 Basf Ag A process for preparing aqueous polymer dispersions and their use
US5173523A (en) * 1985-12-07 1992-12-22 Basf Aktiengesellschaft Aqueous polymer emulsions and their preparation
JPH0714985B2 (en) * 1986-04-09 1995-02-22 旭化成工業株式会社 Method of manufacturing the excellent latexes of water-resistant
EP0256500A3 (en) * 1986-08-20 1990-01-24 The Glidden Company Emulsion polymers containing acrylonitrile or vinylidene chloride
JPH0820604A (en) * 1994-07-06 1996-01-23 Kanebo Nsc Ltd Production of hollow polymer particle
US7008901B2 (en) 2000-01-19 2006-03-07 Mitsui Chemicals, Inc. Emulsion for thermal recording material and thermal recording materials made by using the same
EP1167061B1 (en) * 2000-01-19 2006-06-14 Mitsui Chemicals, Inc. Emulsion for thermal recording material and thermal recording materials made by using the same
CN100384641C (en) * 2002-05-21 2008-04-30 王子制纸株式会社 Ink-jet recording paper
EP2420541B1 (en) 2004-10-20 2015-12-30 Valspar Sourcing, Inc. Methods of coating a food or beverage can
WO2012089747A1 (en) 2010-12-29 2012-07-05 Akzo Nobel Coatings International B.V. Latex emulsions and coating compositions formed from latex emulsions

Also Published As

Publication number Publication date Type
JPS5328687A (en) 1978-03-17 application
CA1102465A1 (en) grant
GB1555868A (en) 1979-11-14 application

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