CA1148678A - Epoxy-amine adduct water soluble acid, and phenoplast or aminoplast crosslinker aqueous coating composition - Google Patents
Epoxy-amine adduct water soluble acid, and phenoplast or aminoplast crosslinker aqueous coating compositionInfo
- Publication number
- CA1148678A CA1148678A CA000328722A CA328722A CA1148678A CA 1148678 A CA1148678 A CA 1148678A CA 000328722 A CA000328722 A CA 000328722A CA 328722 A CA328722 A CA 328722A CA 1148678 A CA1148678 A CA 1148678A
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- coating composition
- aqueous coating
- epoxy
- composition according
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING 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
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
- C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
- C09D5/443—Polyepoxides
- C09D5/4434—Polyepoxides characterised by the nature of the epoxy binder
- C09D5/4438—Binder based on epoxy/amine adducts, i.e. reaction products of polyepoxides with compounds containing amino groups only
-
- 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
- C08G59/1433—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds
- C08G59/1477—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds containing nitrogen
-
- 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
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
- C08G59/50—Amines
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING 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
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Engineering & Computer Science (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Molecular Biology (AREA)
- General Chemical & Material Sciences (AREA)
- Paints Or Removers (AREA)
- Epoxy Resins (AREA)
Abstract
ABSTRACT
1. An aqueous coating composition which comprises (a) a dispersion in an aqueous medium of a product obtained by mixing as the sole film-forming components of the mixture and heating, (i) an epoxy-amine adduct having ionizable nitrogen-containing groups, and (ii) a crosslinking agent for the adduct which is free from carboxyl groups selected from phenol/formaldehyde and aminoplast resins, or blends of these resins to effect an increase in viscosity of the initial mixture of (i) and (ii), and (b) an acid which is capable of ionising the nitrogen-containing groups in the product defined in (a), there being present sufficient of said acid to neutralise at least 30% of the nitrogen-containing groups in and form a stable dispersion of said product in the aqueous medium.
The composition has improved stability at high pH values and at elevated temperatures and is particularly suitable for cathodic deposition.
1. An aqueous coating composition which comprises (a) a dispersion in an aqueous medium of a product obtained by mixing as the sole film-forming components of the mixture and heating, (i) an epoxy-amine adduct having ionizable nitrogen-containing groups, and (ii) a crosslinking agent for the adduct which is free from carboxyl groups selected from phenol/formaldehyde and aminoplast resins, or blends of these resins to effect an increase in viscosity of the initial mixture of (i) and (ii), and (b) an acid which is capable of ionising the nitrogen-containing groups in the product defined in (a), there being present sufficient of said acid to neutralise at least 30% of the nitrogen-containing groups in and form a stable dispersion of said product in the aqueous medium.
The composition has improved stability at high pH values and at elevated temperatures and is particularly suitable for cathodic deposition.
Description
r B67~
COATING COMPOSITIO~S
This invention relates to the preparation of agueous coating compositions; in particular to such compositions which are useful for application to a conductive sub~trate by electrodeposition.
A conductive substrate may be coated with certain synthetic film-forming polymers by immer3ing the substrate in an aqueous dispersion of the polymar and making the substrate one electrode in an electrical circuit through which is passed a suitable electrical current. The current is passed between the substrate and a counter-electrode, the counter-electrode being in electrical contac~ with the dispersion. Suitable polymers usually contain ionisable groups. Those polymers which are to be deposit~d at an anodic ~ub~rate usually contain anionic groups and those which are to he deposited at a cathodic substrat~ usually contain cationic groups. Other materials may be co-depos~ted at the substrate-electrode with the polymer, for example pigment and/or a crosslinking agent for the polymer.
Deposition of film-forming polymer at a cath-odic substra-te has certain advantages over deposition at at anodic substrate since, for example, there is little or no dissolution of metal from a cathodic metal substrate, .
.
. ~ :
such as a ferrous metal substrate. In the ca~e o~
anodic deposition dissolution of metal can discolour the polymer coating. A furt:her advantage of using a cathodic substrate i3 that a previously applied phosphate onversion coating is substantially unaffected by the passage of electric c:urrent.
Suitable synthetic film-~orming polymers which may be applied by cathodic deposition are tho~e polymers which contain basic nitrogen-containing group~.
Suitable basic nitrogen-containing groups are amino or amine groups or residues of these groups. These polymers are preferably dispersed in an aqueous medium in the presence of an acid, for example lactic acid, which is capable of ionising at least some of the basic nitrogen-containing groups.
A particularly suitable group of synthetic polymers containing basic ~itrogen-containing groups which can be applied to a cathodic substrate are the ionisable epoxy-amine adducts. By the term 'epoxy-ami~e adducts' we mean the product of reacting a compound containing at least two epoxy groups with a primary ox secondary amine (including a diamine). The preparation o~ such epoxy-amine adducts is described in the standard chemical text books, for example in "The ~5 Chemistry o~ Organic Film Formers" by D.H.Solomon (John Wiley & Sons Inc., 1967). Typical epoxy group-containlng ;~
compounds which may be used include ~he linear epoxy I
resins obtained by reacting a polyhydric polynuclear phenol, e.g. bis-phenol A with an epichlorhydrin.
One important re~uirement in a coating comp-osition comprising an aqueous dispersion of syn~hetic film-~ormi~g polymer, and particularly one which is to be applied to a substrate by cathodic deposition under :' 8~71~
industrial conditions, is good stability to prolonged storage or usage and variation in pH or temperature.
In general, the useful polymers having nitrogen-containing groups do not u~ually form true solution~
in an aqueous medium but rather at least part of the polymer exists in the aqueous meclium as discrete liquld, solid, colloidal or other forms of disperse particles which owe their stability in the coating bath to various ~actors. Typical factors are the number and/or the nature of the ionisable basic groups in the polymer and the degree of neutralisation of such groups by an acid.
Whilst the aqueous dispersion3 of these synthetic polymers togather with a desired crosslinking agent, may be of satisfactory stability for certàin purposes, particularly when the pH is relatively low, good stability of the dispersions at a relatively high pH is oftan desired but is frequently not achieved.
Good stability at higher pH values, for exam~le at pH 5 - 7, is desirable since the coulombic yield of polymer deposited at a cathodic substrate is greater due to the smaller amount of neutralising acid required.
We have now found that there is an improvement in the stability of aqueous coating compositions, ~5 particularly suitable for cathodic deposition, which `~
comprise a dispersion of an epoxy-amine adduct and certain crosslinking agents for the polymer, when the adduct and the crosslinking agent are mixed and heatad together before they are dispersed in an aqueous medium in the presence of an acid.
According to this invention we providQ an - aqueous coating composition which comprises:
'~
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.
: ,:
8~8 (a~ a dispersion in an aqueous medium o~ a product ob~ained by mixing and heating, (i) an epoxy-amine adduct having ionisable nitrogen-containing groups and (ii) a crosslinking agent for the adduct s~lected from phenol~formaldehyde and aminoplast resins or blends of these resins to effect an increase in viscosity of the ini~ial mixture of (i) and (ii); and 10 (b) an acid which is capable of ionising the nitrogen-containing groups in the product defined in (a), there being present sufficient of said acid to neutralise at least 3~/0 of the nitrogen-containing groups in and form a dispersion of said product in the aqueous medium.
The increase in viscosity of the mixture may be determined by comparing the viscosity of the mixtuxe before and after heating, after dilution with a suitable solvent for example 2-bu~oxyethanol to a solids content of 4~/0 by weight.
Pre~erably the increase in viscosity achievsd by heating is at least 10% and for convenience may be in the range 10 - 70%. The adduct and the crosslinking agent are pre~erably heated substantially in the absenca of added water but preferably one or both of them is or are dissolved or substantially dissolved in a non-aqueou~
solvent before mixing together, and further suitable solvent may be added to the mixture, for exam~le to ensure homogeneity. Suitable solvents include alcohols, glycol ethe:rs and es~ers, ketones, and aromatic hydro~
` carbons.
Preferably, in order to incroase its viscosity ~;
by the desired amount, the mixture of adduct and cross-- `
. ' -, ` ' - ' `
i linking agent is heated at a temperature of at lea~t SOCC and more preferably of 100C or higher, for example in the range loo - 150C. E[eating may be continued for a~y desired period o~ time, for example over ~ to 5 hours.
The viscosity of the mixture before and after heating may ~e determined b~ those conventional procedures which are used in the coating art.
The reaction product obtained by mixing and heating the polymer and crosslinking agent may be dis-persed in an aqueous medium in the presence o~ the acid by suitable procedures. Suitable acids to be used in the aqueous coating compositions of the invention include phosphoric, acetic, lactic, dimethylolpropionic, methane sulphonic and gluconic acids.
Particularly suitable crosslinking agents are phenol/formaldehyde, urea/formaldellyde and melamine/
formaldehyde resins. Urea/formaldehyde resins are particularly suitable especially when butylated.
Epoxy-amine adducts which are particularly suitable in this invention are those described in British Patent 1,461,823 which ara selected from compounds of formula (a) Bl ~ Al - Cl - A2 ~ B2 or (b) B1 Al ~ C1 - A2 ~ C2 - A3 - B2 ' wherein Al A2 and ~ are residues of essont~
ially straight chain di-epoxides and are fr~o of unreacted epoxide groups, Bl and B2 are residues of primary or secondary monoamines o~ p ~ value not greater than 4 and Cl and C
are residues of diamines or primary monoc~mines t:he adduct having a molecular weight of from ~-,500 ~0 7,000.
' ' -. ,.
. .
- , :
These adducts are prepared by reacting essentially linear epoxy resins, for example those prepared by reacting a polyhydric polynuclear phenol with an epichlorhydrin, with suitable primary or secondary amines or diaminec;. Typical epoxy resins from which Al A2 and A3 may be derived have a molecular weight in the range 400 - 4C)OO and contain two epo~y groups per molecule. Typical amines to provide the rasidues Bl and B2 are dimethylamine and diethylamine.
Typical amines to provide the residues Cl and C2 are ethylamine and ethylene diamine.
Other epoxy-amine adducts which may be used in this invention will be known to those skilled in the art.
15The good stability at high ~mperature~ o~
the product obtained by premixing and heating is useful in that an emulsion of the product can be prepared at high temperatures. There is the further advantage of stability at these higher temperatures that a smaller proportion of neutralising acid is necessary and thu~
dispersions of higher solids content may be prepared.
The aqueous coating compositions of this invention may contain pigment and other conventional `
paint additives. The compositions may be used in application processes other than cathodic electro~
deposition, for example in spraying or brushing.
The invention is illustrated by the follow~
Examples in which parts and percentages are ~y weight:
, :
!
" , i~
, '' , ' ' ' ' ' .'' ' .
.. ... . ... .. ....
EXAMoeLE 1 ¦ (a) Preparatlon of an epoxy-amine adduct The following ingredients
COATING COMPOSITIO~S
This invention relates to the preparation of agueous coating compositions; in particular to such compositions which are useful for application to a conductive sub~trate by electrodeposition.
A conductive substrate may be coated with certain synthetic film-forming polymers by immer3ing the substrate in an aqueous dispersion of the polymar and making the substrate one electrode in an electrical circuit through which is passed a suitable electrical current. The current is passed between the substrate and a counter-electrode, the counter-electrode being in electrical contac~ with the dispersion. Suitable polymers usually contain ionisable groups. Those polymers which are to be deposit~d at an anodic ~ub~rate usually contain anionic groups and those which are to he deposited at a cathodic substrat~ usually contain cationic groups. Other materials may be co-depos~ted at the substrate-electrode with the polymer, for example pigment and/or a crosslinking agent for the polymer.
Deposition of film-forming polymer at a cath-odic substra-te has certain advantages over deposition at at anodic substrate since, for example, there is little or no dissolution of metal from a cathodic metal substrate, .
.
. ~ :
such as a ferrous metal substrate. In the ca~e o~
anodic deposition dissolution of metal can discolour the polymer coating. A furt:her advantage of using a cathodic substrate i3 that a previously applied phosphate onversion coating is substantially unaffected by the passage of electric c:urrent.
Suitable synthetic film-~orming polymers which may be applied by cathodic deposition are tho~e polymers which contain basic nitrogen-containing group~.
Suitable basic nitrogen-containing groups are amino or amine groups or residues of these groups. These polymers are preferably dispersed in an aqueous medium in the presence of an acid, for example lactic acid, which is capable of ionising at least some of the basic nitrogen-containing groups.
A particularly suitable group of synthetic polymers containing basic ~itrogen-containing groups which can be applied to a cathodic substrate are the ionisable epoxy-amine adducts. By the term 'epoxy-ami~e adducts' we mean the product of reacting a compound containing at least two epoxy groups with a primary ox secondary amine (including a diamine). The preparation o~ such epoxy-amine adducts is described in the standard chemical text books, for example in "The ~5 Chemistry o~ Organic Film Formers" by D.H.Solomon (John Wiley & Sons Inc., 1967). Typical epoxy group-containlng ;~
compounds which may be used include ~he linear epoxy I
resins obtained by reacting a polyhydric polynuclear phenol, e.g. bis-phenol A with an epichlorhydrin.
One important re~uirement in a coating comp-osition comprising an aqueous dispersion of syn~hetic film-~ormi~g polymer, and particularly one which is to be applied to a substrate by cathodic deposition under :' 8~71~
industrial conditions, is good stability to prolonged storage or usage and variation in pH or temperature.
In general, the useful polymers having nitrogen-containing groups do not u~ually form true solution~
in an aqueous medium but rather at least part of the polymer exists in the aqueous meclium as discrete liquld, solid, colloidal or other forms of disperse particles which owe their stability in the coating bath to various ~actors. Typical factors are the number and/or the nature of the ionisable basic groups in the polymer and the degree of neutralisation of such groups by an acid.
Whilst the aqueous dispersion3 of these synthetic polymers togather with a desired crosslinking agent, may be of satisfactory stability for certàin purposes, particularly when the pH is relatively low, good stability of the dispersions at a relatively high pH is oftan desired but is frequently not achieved.
Good stability at higher pH values, for exam~le at pH 5 - 7, is desirable since the coulombic yield of polymer deposited at a cathodic substrate is greater due to the smaller amount of neutralising acid required.
We have now found that there is an improvement in the stability of aqueous coating compositions, ~5 particularly suitable for cathodic deposition, which `~
comprise a dispersion of an epoxy-amine adduct and certain crosslinking agents for the polymer, when the adduct and the crosslinking agent are mixed and heatad together before they are dispersed in an aqueous medium in the presence of an acid.
According to this invention we providQ an - aqueous coating composition which comprises:
'~
` . !:
.
: ,:
8~8 (a~ a dispersion in an aqueous medium o~ a product ob~ained by mixing and heating, (i) an epoxy-amine adduct having ionisable nitrogen-containing groups and (ii) a crosslinking agent for the adduct s~lected from phenol~formaldehyde and aminoplast resins or blends of these resins to effect an increase in viscosity of the ini~ial mixture of (i) and (ii); and 10 (b) an acid which is capable of ionising the nitrogen-containing groups in the product defined in (a), there being present sufficient of said acid to neutralise at least 3~/0 of the nitrogen-containing groups in and form a dispersion of said product in the aqueous medium.
The increase in viscosity of the mixture may be determined by comparing the viscosity of the mixtuxe before and after heating, after dilution with a suitable solvent for example 2-bu~oxyethanol to a solids content of 4~/0 by weight.
Pre~erably the increase in viscosity achievsd by heating is at least 10% and for convenience may be in the range 10 - 70%. The adduct and the crosslinking agent are pre~erably heated substantially in the absenca of added water but preferably one or both of them is or are dissolved or substantially dissolved in a non-aqueou~
solvent before mixing together, and further suitable solvent may be added to the mixture, for exam~le to ensure homogeneity. Suitable solvents include alcohols, glycol ethe:rs and es~ers, ketones, and aromatic hydro~
` carbons.
Preferably, in order to incroase its viscosity ~;
by the desired amount, the mixture of adduct and cross-- `
. ' -, ` ' - ' `
i linking agent is heated at a temperature of at lea~t SOCC and more preferably of 100C or higher, for example in the range loo - 150C. E[eating may be continued for a~y desired period o~ time, for example over ~ to 5 hours.
The viscosity of the mixture before and after heating may ~e determined b~ those conventional procedures which are used in the coating art.
The reaction product obtained by mixing and heating the polymer and crosslinking agent may be dis-persed in an aqueous medium in the presence o~ the acid by suitable procedures. Suitable acids to be used in the aqueous coating compositions of the invention include phosphoric, acetic, lactic, dimethylolpropionic, methane sulphonic and gluconic acids.
Particularly suitable crosslinking agents are phenol/formaldehyde, urea/formaldellyde and melamine/
formaldehyde resins. Urea/formaldehyde resins are particularly suitable especially when butylated.
Epoxy-amine adducts which are particularly suitable in this invention are those described in British Patent 1,461,823 which ara selected from compounds of formula (a) Bl ~ Al - Cl - A2 ~ B2 or (b) B1 Al ~ C1 - A2 ~ C2 - A3 - B2 ' wherein Al A2 and ~ are residues of essont~
ially straight chain di-epoxides and are fr~o of unreacted epoxide groups, Bl and B2 are residues of primary or secondary monoamines o~ p ~ value not greater than 4 and Cl and C
are residues of diamines or primary monoc~mines t:he adduct having a molecular weight of from ~-,500 ~0 7,000.
' ' -. ,.
. .
- , :
These adducts are prepared by reacting essentially linear epoxy resins, for example those prepared by reacting a polyhydric polynuclear phenol with an epichlorhydrin, with suitable primary or secondary amines or diaminec;. Typical epoxy resins from which Al A2 and A3 may be derived have a molecular weight in the range 400 - 4C)OO and contain two epo~y groups per molecule. Typical amines to provide the rasidues Bl and B2 are dimethylamine and diethylamine.
Typical amines to provide the residues Cl and C2 are ethylamine and ethylene diamine.
Other epoxy-amine adducts which may be used in this invention will be known to those skilled in the art.
15The good stability at high ~mperature~ o~
the product obtained by premixing and heating is useful in that an emulsion of the product can be prepared at high temperatures. There is the further advantage of stability at these higher temperatures that a smaller proportion of neutralising acid is necessary and thu~
dispersions of higher solids content may be prepared.
The aqueous coating compositions of this invention may contain pigment and other conventional `
paint additives. The compositions may be used in application processes other than cathodic electro~
deposition, for example in spraying or brushing.
The invention is illustrated by the follow~
Examples in which parts and percentages are ~y weight:
, :
!
" , i~
, '' , ' ' ' ' ' .'' ' .
.. ... . ... .. ....
EXAMoeLE 1 ¦ (a) Preparatlon of an epoxy-amine adduct The following ingredients
2-ethoxy ethanol 10.0 part~
n-butanol 3.3 parts epoxy re~in (having epoxide equivalent of 475 and commercially available as "Epikote" 1001) 13.4 p?rts epoxy resin (having epoxide equivalent of 901 and commercially available as "Epikote" 1004) 13.4 parts were heated to 80 - 103C with st~rring until dissolved.
Diethylamine 1.6 part3 was addea to the above solution at 50C and after 2 hours at 55C there was added~
Ethylen~ diamine 0.4 part The temperature was maintained at 55C for 3 hours, raised to 115C over 1 hour and heating under reflux was continued for 1 hour. 1.2 part~
of volatile materials were then removed by diqtillation at 115-130C.
tb) Preheating of epoxy-amine adduct and urea~
formaldehvde re~in A mixture of epo~-amine adduct as obtained in (a) above 55'7 part~
~ and urea/formaldehyde (a 53% solution :~
; `: 30 in ~lol/butanol o~ a butylated ~ ~ i urea/formaldehyde ra~in : .
: ~ . (urea/formaldehyde = 1/2.25 molar) 18.9 part~
were heated for 3 hours at 100 - 120 C during:
: which time the viscosity of a sample (diluted to ~ ~ .
.
~ ~ :
: ~:
. . . . -. -~. , . , , . : - : . :
: .
: . . . .
. . .
. ~ ........ . , ' ~ ', ' ~
4~/0 solids by weight with 2-butoxy ethanol~
increased from 8.0 stokes to 10.0 stokes.
(c) Preparation of unpiqmented coatinq compositions 1) Accordinq to the invention The total product of (b~ above (74.7 parts ) was cooled and emulsified by mixing with Commercial lactic acid (free lactic acid content of 71.4%
by titration) 4.1 part3 and water 77.5 parts The translucent emulsion produced had a pH
of 5.5 - 6.5 and was stable for at least
n-butanol 3.3 parts epoxy re~in (having epoxide equivalent of 475 and commercially available as "Epikote" 1001) 13.4 p?rts epoxy resin (having epoxide equivalent of 901 and commercially available as "Epikote" 1004) 13.4 parts were heated to 80 - 103C with st~rring until dissolved.
Diethylamine 1.6 part3 was addea to the above solution at 50C and after 2 hours at 55C there was added~
Ethylen~ diamine 0.4 part The temperature was maintained at 55C for 3 hours, raised to 115C over 1 hour and heating under reflux was continued for 1 hour. 1.2 part~
of volatile materials were then removed by diqtillation at 115-130C.
tb) Preheating of epoxy-amine adduct and urea~
formaldehvde re~in A mixture of epo~-amine adduct as obtained in (a) above 55'7 part~
~ and urea/formaldehyde (a 53% solution :~
; `: 30 in ~lol/butanol o~ a butylated ~ ~ i urea/formaldehyde ra~in : .
: ~ . (urea/formaldehyde = 1/2.25 molar) 18.9 part~
were heated for 3 hours at 100 - 120 C during:
: which time the viscosity of a sample (diluted to ~ ~ .
.
~ ~ :
: ~:
. . . . -. -~. , . , , . : - : . :
: .
: . . . .
. . .
. ~ ........ . , ' ~ ', ' ~
4~/0 solids by weight with 2-butoxy ethanol~
increased from 8.0 stokes to 10.0 stokes.
(c) Preparation of unpiqmented coatinq compositions 1) Accordinq to the invention The total product of (b~ above (74.7 parts ) was cooled and emulsified by mixing with Commercial lactic acid (free lactic acid content of 71.4%
by titration) 4.1 part3 and water 77.5 parts The translucent emulsion produced had a pH
of 5.5 - 6.5 and was stable for at least
3 months. Its particle size was too small to resolve by optical microscopy. A cathodic substrate was satisfactorily coatediby electrodeposition using this emulsion.
(ii) ot accordinq to the invention ~-Epoxy-amine adduct from (a) 55.7 parks Urea/formaldehyde resin as in (b) 18.9 parts were mixed without heating and emul~ified in a solution of lactic acid in water in the manner described in (i). The emulsion produced had a mi~Xy appearance~ It settled out on storage after several days and ~ I
discrete particles were just visible under ~ t an optical microscope X400.
` A similar result was obtained wh~n the urea/ ' formaldehyde resin was replaced hy an equivalent 3~ amount of a melamine/formaldehyde resin.
~, : . I
: ' .
.
' 8t~7~
_ g _ ~a) Preparation of an epoxy-amine adduct 1000 parts of an epoxy resin (of epoxide value approximately 900 and commercially available as "Epikote" 1004) were dissolved in 250 parts of methyl isobutyl Xetone and warmed to 50C. 40 parts of di-ethylamine was added and allowed to react for one hour. This was followed by the addition of 16 part~ ;
of ethylene diamine which was allowed to react for 3 , hours at 50 C followed by one hour at 100 C.
(b~ Preheating of epoxy-amine adduct and phenol-formaldehYde resin ~
To the product in (a) (which had an epoxide value equivalent to 2 mg KOH/g) were added 211 parts of a phenol/formaldehyde resin commercially avail~ble as "Uranox L9". The mixture was heated at 100 - 120C
for 3 hours during which time there was a significant increase in viscosity (greater than 10%).
(c~ The product of (b) was emulsified in water in the presence of lactic acid as described in Example 1.
The translucent emulsion had a pH o 5.5 - 6.5 and was stable for at least 3 mo~ths. A cathodic substrate wa~
satisfactorily coated by electrodeposition using this - emulsion. When the epoxy-amine adduct and phenol-formaldehyde resin were not preheated an emulsion produced in the same way was unstable. , .
O
: . , , ~ ~ :
.
- : :
(ii) ot accordinq to the invention ~-Epoxy-amine adduct from (a) 55.7 parks Urea/formaldehyde resin as in (b) 18.9 parts were mixed without heating and emul~ified in a solution of lactic acid in water in the manner described in (i). The emulsion produced had a mi~Xy appearance~ It settled out on storage after several days and ~ I
discrete particles were just visible under ~ t an optical microscope X400.
` A similar result was obtained wh~n the urea/ ' formaldehyde resin was replaced hy an equivalent 3~ amount of a melamine/formaldehyde resin.
~, : . I
: ' .
.
' 8t~7~
_ g _ ~a) Preparation of an epoxy-amine adduct 1000 parts of an epoxy resin (of epoxide value approximately 900 and commercially available as "Epikote" 1004) were dissolved in 250 parts of methyl isobutyl Xetone and warmed to 50C. 40 parts of di-ethylamine was added and allowed to react for one hour. This was followed by the addition of 16 part~ ;
of ethylene diamine which was allowed to react for 3 , hours at 50 C followed by one hour at 100 C.
(b~ Preheating of epoxy-amine adduct and phenol-formaldehYde resin ~
To the product in (a) (which had an epoxide value equivalent to 2 mg KOH/g) were added 211 parts of a phenol/formaldehyde resin commercially avail~ble as "Uranox L9". The mixture was heated at 100 - 120C
for 3 hours during which time there was a significant increase in viscosity (greater than 10%).
(c~ The product of (b) was emulsified in water in the presence of lactic acid as described in Example 1.
The translucent emulsion had a pH o 5.5 - 6.5 and was stable for at least 3 mo~ths. A cathodic substrate wa~
satisfactorily coated by electrodeposition using this - emulsion. When the epoxy-amine adduct and phenol-formaldehyde resin were not preheated an emulsion produced in the same way was unstable. , .
O
: . , , ~ ~ :
.
- : :
Claims (10)
1. An aqueous coating composition which comprises (a) a dispersion in an aqueous medium of a product obtained by mixing as the sole film-forming components of the mixture and heating, (i) an epoxy-amine adduct having ionisable nitrogen-containing groups, and (ii) a crosslinking agent for the adduct which is free from carboxyl groups selected from phenol/formaldehyde and aminoplast resins, or blends of these resins to effect an increase in viscosity of the initial mixture of (i) and (ii), and (b) an acid which is capable of ionising the nitrogen-containing groups in the product defined in (a), there being present sufficient of said acid to neutralise at least 30% of the nitrogen-containing groups in and form a stable dispersion of said product in the aqueous medium.
2. An aqueous coating composition according to claim 1 wherein there is an increase in viscosity of the initial mixture of (i) and (ii) of at least 10%
on a 40% by weight resin solids basis.
on a 40% by weight resin solids basis.
3. An aqueous coating composition according to claim 1 wherein the mixture of and (ii) is heated to a temperature of at least 50%.
4. An aqueous coating composition according to Claim 1, 2 or 3 ¦wherein (i) and (ii) are mixed and heated substantially in the absence of water.
5. An aqueous coating composition according to Claim 1, 2 or 3 ¦wherein the acid is selected from phosphoric, lactic and acetic acids.
6. An aqueous coating composition according to Claim 1, 2 or 3 ¦wherein the crosslinking agent is a urea/formaldehyde, or melamine/formaldehyde resin.
7. An aqueous coating composition according to claim 1, 2 or¦
3 wherein the crosslinking agent is a butylated urea/formaldehyde resin.
3 wherein the crosslinking agent is a butylated urea/formaldehyde resin.
8. An aqueous coating composition according to Claim 1, 2 or 3 ¦wherein the epoxy-amine adduct comprises a compound of formula (a) B1 - A1 - C1 - A2 - B2 or (b) B1 - A1 - C1 - A2 - C2 - A3 - B2, wherein A1, A2 and A3 are residues of essentially straight chain di-epoxides and are free from unreacted epoxide groups, B1 and B2 are residues of primary or secondary monoamines or pKb value not greater than 4, and C1 and C2 are residues of diamines or primary monoamines, the adduct having a molecular weight of from 1,500 to 7,000.
9. A process for preparing an aqueous coating composition which comprises (a) mixing and heating, (i) epoxy-amine adduct having ionisable nitrogen-containing groups and (ii) a crosslinking agent for the adduct selected from phenol/formaldehyde and aminoplast resins or blends of these resins to effect an increase in viscosity of the initial mixture of (i) and (ii), including any non-aqueous solvent which is present, of at least 10%;
and (b) dispersing the product of (a) in an aqueous medium in the presence of an acid which is capable of ionising the nitrogen-containing groups in the product of (a), there being sufficient of said acid to neutralise at least 30% of said basic groups and form a stable dispersion of said product in the
and (b) dispersing the product of (a) in an aqueous medium in the presence of an acid which is capable of ionising the nitrogen-containing groups in the product of (a), there being sufficient of said acid to neutralise at least 30% of said basic groups and form a stable dispersion of said product in the
10. A method of coating a conductive substrate by electrodeposition wherein an electric current is passed between the substrate as cathode and another electrode immersed in an aqueous coating composition according to Claim 1, 2 or 3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB23776/78A GB1604545A (en) | 1978-05-30 | 1978-05-30 | Coating compositions |
| GB23776/78 | 1978-05-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1148678A true CA1148678A (en) | 1983-06-21 |
Family
ID=10201148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000328722A Expired CA1148678A (en) | 1978-05-30 | 1979-05-30 | Epoxy-amine adduct water soluble acid, and phenoplast or aminoplast crosslinker aqueous coating composition |
Country Status (9)
| Country | Link |
|---|---|
| AU (1) | AU4733879A (en) |
| CA (1) | CA1148678A (en) |
| CS (1) | CS209809B2 (en) |
| FR (1) | FR2427368A1 (en) |
| GB (1) | GB1604545A (en) |
| IT (1) | IT1121516B (en) |
| NZ (1) | NZ190540A (en) |
| PL (1) | PL215924A1 (en) |
| ZA (1) | ZA792636B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3538548A1 (en) * | 1985-10-30 | 1987-05-07 | Hoechst Ag | METHOD FOR PRODUCING SOLUBLE RESIN RESIN FREE FROM MONOMERIC AMINES WITH NH BONDS AND THE USE THEREOF |
| AT409964B (en) | 2000-11-15 | 2002-12-27 | Solutia Austria Gmbh | SELF-CROSSLINKING WATER-THINNABLE BINDERS |
| CN100436559C (en) * | 2006-11-21 | 2008-11-26 | 中国化工建设总公司常州涂料化工研究院 | Crosslinking agent in use for baking coating material of epoxy resin in monocomponent |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1199497B (en) * | 1962-10-23 | 1965-08-26 | Albert Ag Chem Werke | Mixture with phenol-aldehyde condensation products as hardeners for epoxy resins |
| SE409466B (en) * | 1973-06-04 | 1979-08-20 | Dulux Australia Ltd | AQUATIC COATING COMPOSITION, SUITABLE FOR CATODIC ELECTRIC PACKAGING, CONTAINING AN IONIZABLE SALT OF AN EPOXI-AMINE ADDUCT AND AN ACID AND SET FOR ITS PREPARATION |
-
1978
- 1978-05-30 GB GB23776/78A patent/GB1604545A/en not_active Expired
-
1979
- 1979-05-23 AU AU47338/79A patent/AU4733879A/en not_active Abandoned
- 1979-05-24 NZ NZ190540A patent/NZ190540A/en unknown
- 1979-05-28 IT IT23045/79A patent/IT1121516B/en active
- 1979-05-28 PL PL21592479A patent/PL215924A1/xx unknown
- 1979-05-29 FR FR7913570A patent/FR2427368A1/en not_active Withdrawn
- 1979-05-29 ZA ZA792636A patent/ZA792636B/en unknown
- 1979-05-30 CA CA000328722A patent/CA1148678A/en not_active Expired
- 1979-05-30 CS CS793727A patent/CS209809B2/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IT1121516B (en) | 1986-04-02 |
| NZ190540A (en) | 1981-07-13 |
| GB1604545A (en) | 1981-12-09 |
| FR2427368A1 (en) | 1979-12-28 |
| CS209809B2 (en) | 1981-12-31 |
| AU4733879A (en) | 1979-12-06 |
| ZA792636B (en) | 1980-11-26 |
| IT7923045A0 (en) | 1979-05-28 |
| PL215924A1 (en) | 1980-02-25 |
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