CA1121091A - Aqueous coating agents and a process for their preparation - Google Patents
Aqueous coating agents and a process for their preparationInfo
- Publication number
- CA1121091A CA1121091A CA000295556A CA295556A CA1121091A CA 1121091 A CA1121091 A CA 1121091A CA 000295556 A CA000295556 A CA 000295556A CA 295556 A CA295556 A CA 295556A CA 1121091 A CA1121091 A CA 1121091A
- Authority
- CA
- Canada
- Prior art keywords
- weight
- parts
- oil
- aqueous dispersion
- alkyd resin
- 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
- 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
- C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
- C09D101/08—Cellulose derivatives
- C09D101/16—Esters of inorganic acids
- C09D101/18—Cellulose nitrate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
- C08K5/0016—Plasticisers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/08—Cellulose derivatives
- C08L1/16—Esters of inorganic acids
- C08L1/18—Cellulose nitrate, i.e. nitrocellulose
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
- C08L29/02—Homopolymers or copolymers of unsaturated alcohols
- C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
- C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/08—Polyesters modified with higher fatty oils or their acids, or with resins or resin acids
-
- 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
- C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
- C09D101/08—Cellulose derivatives
-
- 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
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/08—Polyesters modified with higher fatty oils or their acids, or with natural resins or resin acids
Abstract
Aqueous coating agents and a process for their preparation Abstract of the Disclosure Aqueous dispersion of coating agents consisting of 5 - 50 parts by weight of nitrocellulose ester, 5 - 30 parts by weight of plasticiser, 5 - 50 parts by weight of aslkyd resin, 30 - 135 parts by weight of water and 0.5 - 10 parts by weight of emulsifer.
Le A 17 836
Le A 17 836
Description
d2~
Aqueous coating agents, for example for lacquerin~ furniture, have hitherto generally contained synthetic resins, such as acrylic polymers or cellulose esters, as the film-formang agents. Methods Eor preparing aqueous emulsions of suitable cellulose derivatives are known and are described, for example, in German Auslegeschrift 1,286,672 and United States Patent 3,615,792. Emulsions of cellulose esters, for example of nitrocellulose, cannot be used as the sole binders for coating agents, because they only produce brittle and fragile films. m ey must be combined with ketone resins or vinyl acetate copolymers in order to achieve glossy coatings with good mechanical properties.
Cellulose esters, for example nitrocellulose, usually combined with alkyd resins, are used for lacquering wcod or similar materials. m is combination leads to coatings of high gloss, adequate hardness, good elasticity and excellent flow, but it is not possible to work with aqueous emulsions; instead, these combinations have hitherto had to be processed from organic solutions. All attempts hitherto to emulsify aIkyd resins and cellulose esters lead either to emulsions of inadequate stability or to e~,ulsions with particles which are too coarse and which do not permit levelling to give glossv coatings.
m e invention relates to aqueous dispersions of coating agents in which the dispersed particles have a size from 0.1 to 1.5~ camprising 5-50 parts by weight of cellulose ester, 5-30 parts by weight of plasticiser, 5-50 parts by weight of alkyd resin, 30-135 parts by weight of water and 0.5- 10 parts by weight of emulsifier, in which ~he emulsifier is a vinyl alcohol homopolymer or copolymer and the alkyd resin is a short-oil aIkyd resin containing 5-50% by weight of oil.
These dispersions are stable and can give coatings of . . .
substantially ~aultlass glos~.
The invention further relates to a process for the pre-paration of such dispersions o~ coating agents, which is characterised in that a cellulose ester, an alkyd resin and a plasticiser are dissolved in an organic solvent, this solution is dispersed into a solution consisting o~ emulsi~ier and water and the organic solvent is removed by distillation.
The size of the dispersed particles is particularly important for the stability of the di~persion and also ~or its behaviour in film formation. According to the invention it is preferably 0.1 to 0.5~ and it does not change substantially even on prolonged storage at 5-50C.
Cellulose esters which can be used in accordancs with the in~ention are, in particular, cellulose acetate, cellulose aoetobutyrate, cellulose acetate-benzoate and cellulose sorbate-acetate and mixtures of these esterq. Ni~rocellulose, for example the customary collodion cotton qualities, that is to 3ay cellulose nitric acid esters having a nitrogen content of ; 10.2 to 12.4% by weight, is more particularly suitable.
Plasticisers within the me~ing of the invention are, i~ particular, esters, such as dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dibutyl adipate, benzylbutyl adipate, dioctyl adipate, phosphoric acid esters, such as tri-cresyl phosphate, triphenyl phosphate or trioctyl phosphate, ~nd also benzenesulphonic aci~ N-methylamide.
Suitable alkyd resins are preferably oil-modified or ; ~atty acid-modified alkyd resins. Alkyd resins are under-stood a~ polyesters which are prepared from alcohol~ and carboxylic acids by polycondensation according to known pro-30l cesses and such as are defined; for ex~mple, in Ullmanns-Enzyklopadle der Teohnischen Chemie (Ullmann's Encyclopaedla 9~L
of Industrial Chemistry) or are described in D.R. Sol~mon, The Chemistry of Organic Filmformers, page 75-111. In general, the alcohols employed cantain 1 to 15, preferably 2 to 6, C atcms and the acids used, or their ester-formang derivatives, contain 2 to 14, preferably 4 to 12, C atoms. These alkyd resins can optionally be mixed with other polyesters, for example also with oil-free poly-esters.
Examples of suitable alcohols are pentaerythritol, glycerol, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, 1,2,6-hexanetriol, ethylene glycol, propane-1,2-diol,propane-1,3-diol, butane-1,2-diol, butane-1,3-diol and butane-1,4-diol, neo-pentylglycol, diethylene glycol, triethylene glycol, dipropylene glycol, hexane-1,6-diol,1,2-bis-(hydroxymethyl)-cyclohexane and 1,4-bis-(hydroxymethyl)-cyclohexane, 2-ethylpropane-1,3-diol, 2-ethyl-hexane-1,3-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and adipic acid bis-ethylene glycol ester; benzyl alcohol, cyclohexanol and other monoalcohols having 1 to 6 C atoms. Preferred alcohols are gly oerol, trimethylolpropane, neopentylglycol and pentaerythri-tol.
The following carboxylic acids, or their ester-formLng derivatives, may be mentioned as examples of suitable ad d COmpOIl-ents: phthalic acid, isophthalic acid, terephthalic acid, tetra-hydrophthalic acid and hexcahydrophthalic acid, endomethylene-tetrahydrophthalic acid, succinic acid, adipic acid, sebacic acid, trimellitic acid, benzoic acid and their derivatives, such as, for example, p-tert.-butylbenzoic acid and hexahydrobenzoic acid.
Phthalic acid is the most customary.
In the alkyd resins which are employed for the coating emulsions according to the invention, the proportion of oil can be 5 to 50% by weight, calculated as triglyceride and relative 11~105al to the alkyd resin. The drying or non-drying fatty aciJs which generally contain 6 to 24 C atoms, can be employed either as such or in the form o~ their glycerol esters (triglycerides), Animal and vegetable oils, ~ats or fQtty acids~ such as, ~or example, coconut oil, groundnut oil, castor oil, olive oil, soya bean oil, linseed oil, cottonseed oil 9 sa~flower oil or safflower oil ~atty acids, dehydrated castor oil or castor oil fatty acid, mono-unsaturated ~atty acids, lard, tallow and train oils, tall oil fatty acid and synthetic fatty acids, ~ay be mentioned as being suitable.
Suitable emulsiflers are homopolymers and copolymers of vinyl alcohol, for example polyvinyl alcohols which are formed by hydrolysis of polyvinyl acetate and which are available commercially, for example under the de~ignation Polyviol 15 I W 25/240 and W 25/140. Hydrolysed copolymers of vinyl-pyrrolidone and vinyl acetate are also suitable.
The dispersions o~ coating agents of the invention pre-ferably contain alkyd resins having an oil content of 20 to 45%.
The coatings according to the in~ention can be produced by dissolving the alkyd resin, the cellulose ester and the plasticiser in a polar solvent which is not soluble in water9 and which can be removed by dis~illation from the emulsion to be ~ormed, combining the solution with an aqueous solution of the emulsifier and thus forming an oil-in-water emulsion by means of high shearing forces. The organic solvent is then removed by di~tillation, on ~ts own or in the form o~ an aqueous a~eotrope. Solvents ~hich are particularly suitable are alkyl acetates and alkyl propionates. The aqueous emulsion which remains can be diluted with more water or a suitable coalascing agent can be added to it. In the ~ollowing -~ Trac~
this will be designated a secondary emulsion.
One or more coalescing or aggregating agents can also be added to the dispersion in order to achieve a clear film of high gloss. Coalescing agents which form an azeotrope with the water are preferred here. It is then necessary to add to the dispersion sufficient coalescing agent so that -the azeotrope is first distilled o~ and, in addition, to add further ooalescing agent which ef~ects the aggregation of the particles. Possible coalescing agents are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene ~lycol monobutyl ether-acetate diethylene glycol, diethylene glycol monobutyl ether, diacetone alodhcl methylgly-col acetate, methyl amyl ketone and diisobutyl ketone.
The primary emulsion consisting of cellulose ester, alkyd resin, emul~ifier, plasticiser, water and organic ~olvent i~ produced in a commercially available device having an adcquately high peripheral speed of 5 to 50 m/second, prefer ably 10-30 m/~econd.
Examples are: Ultra-Tu~a ~type 45 of 10,000 revolutions per minute; Gaulin homogeniser, di~;sol~er and beadmillsO
The emul~i~ica~ion time in the Ultra-Tun~x~hould not ; be more than 2 minutes, since otherwlse too great an e~olution of heat takes place This time is adequate to produce small, spherical particle~ of Q1-1.5pr0~rably Q1-0.5/u Pro~th~
~ ltu~rts o~ the ultimate emulsion.
In a pre~erred embodime~, the aqueou~ coating composit~on~
contain add1tionally 4 - 40 par~s by w~ight o~ an urea and/or m~lamine re~inO
Ur~a a~d melami~e re~ln~ in thi~ context are art recognized conden5ation product~ o~ ur~a or melamine and ~ormaldehyde which ar~ made in an alkaline medium. They are 501uble in water and are add~d to the di~p~rsion~ in the Iorm OI aqueou~ ~olutions~ Their ef~ect is a cros~linking of the coatings obtained from the disper ~ions which improves their stabillty and gloss. Catalytic amounts of p-toluene sulfonic acid accelerate crosslinking.
A solution in ethyl acetate wa~ prepared from:
100 g of nitrocellulose chips containing approximately 12% of nitrogen, Standard Specification 24 E in accordance with DIN 53,179, consisting of 82% of collodion cotton and 18%
of dibu-tyl phthalate, 0 100 g of groundnut oil fatty acld alkyd resin having an oil content of 41~, and of ethyl acetate 500 g After stirring slowly for approximately 3 hours a clear solution was obtained which WR3 combined with 300 g o~
a 3% strength aqueous solution of polyvinyl alcohol (Polyviol W 25/140), whilst stirring slowly, The mixture was then dispersed for 2 mi~utes in an Ultra-Tur~ax~ -type 45 laboratory ~ disperser by raising the speed of rotation continuously to 10,000 revolutio~s per minute. The solvent is distilled o~f under reduced pressure. A primary emulsion having a ~olids content of 40% and a ~low viscosity oX 34 second~ in the DINcup No.4 is thus obtained, which was processed in Example and 30 ~ son example:
A dispersion was prepared as described in Example 1, exceptthat instead of the polyvin~l alcohol 300 g of ~n aqueous solution of a non-ionic fatty acid ester (emulsifier Emulpho~Y~EL of BASF) were used. This ga~e an emulsion 30 which wa~ stable for a short time and which ga~re an average size of 13~ in a determination of particle pattern.
A dispersion was prepared from:
100 g of groundnut oil fatty acid alkyd resin having an oil content of 41%) 100 g of nitrocellulose chips as in Example 1, and o~ ethyl acetate 500 g After stirring for 3 hours, a clear solution was obtained ~hich is combined with 500 g o~ a 2.5% strength solu-tionofpolyvlnylalcaohol (Polyviol W 25/140) in water. The procedure described under Dispersion 1 was then followed. A
primary emulsion with a solids content of approximately 29%
and a flow viscosity of 28 secondsin theDIN cup NoO 4is obtained .U3~
I Example 1 (Comparison) A lacquer of the following composition was prepared:
Groundnut oil fatty acid alkyd resin with 41% of oil, 60% strength solution in xylene 152 parts by weight ~I Collodion cotton (cellulose nitric ac:id ester 1 ~ontaining approximately 12% of nit;rogen), Standard Specification type 24 E, DIN
; 53,179, in the form of chips111 parts by weigh~
Dibutyl phthalate 8 parts by welght i Ethylene glycol monoethyl ether59 parts by weight 2S Bu~yl acetate 190 parts by weight Ethyl acetate 140 parts by weight Xylene 300 parts by weight Ethylglycol acetate40 parts by weight ~ The resulting lacquer exhibited a viscosity correspond-ing to a flow time of approximately 30 seconds, measured in accordance with DIN 53,211 (DIN cup No.4). The curing to give films and the assessment are described in Table 1.
- 8 - .
Example 2 A dispersion of the following composition was prepared:
Dispersion from Example 1, 40% strength in water 550 parts by weight 5 ~ibutyl phthalate 10 parts by weight Ethylene glycol monomethyl ether124 parts by weight Ethylglycol acetate 44 parts by weight 4-Methyl-4-hydroxypentan-2-one32 parts by weight Water 234 parts by weight Levelling agent (alkylbenzenesulphonate) 6 parts by weight The resulting dispersion exhibited a viscosity corres-ponding to a flow time of approximately 15 seconds, measured in accordance with DIN 53,211, g _ .
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,s ~ h ~0 ~ o Q~ ~q 0 ~I h w ~ d w ~d ~ O o rl w 0 ~ O
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Le A 17 8~6 - 10 -
Aqueous coating agents, for example for lacquerin~ furniture, have hitherto generally contained synthetic resins, such as acrylic polymers or cellulose esters, as the film-formang agents. Methods Eor preparing aqueous emulsions of suitable cellulose derivatives are known and are described, for example, in German Auslegeschrift 1,286,672 and United States Patent 3,615,792. Emulsions of cellulose esters, for example of nitrocellulose, cannot be used as the sole binders for coating agents, because they only produce brittle and fragile films. m ey must be combined with ketone resins or vinyl acetate copolymers in order to achieve glossy coatings with good mechanical properties.
Cellulose esters, for example nitrocellulose, usually combined with alkyd resins, are used for lacquering wcod or similar materials. m is combination leads to coatings of high gloss, adequate hardness, good elasticity and excellent flow, but it is not possible to work with aqueous emulsions; instead, these combinations have hitherto had to be processed from organic solutions. All attempts hitherto to emulsify aIkyd resins and cellulose esters lead either to emulsions of inadequate stability or to e~,ulsions with particles which are too coarse and which do not permit levelling to give glossv coatings.
m e invention relates to aqueous dispersions of coating agents in which the dispersed particles have a size from 0.1 to 1.5~ camprising 5-50 parts by weight of cellulose ester, 5-30 parts by weight of plasticiser, 5-50 parts by weight of alkyd resin, 30-135 parts by weight of water and 0.5- 10 parts by weight of emulsifier, in which ~he emulsifier is a vinyl alcohol homopolymer or copolymer and the alkyd resin is a short-oil aIkyd resin containing 5-50% by weight of oil.
These dispersions are stable and can give coatings of . . .
substantially ~aultlass glos~.
The invention further relates to a process for the pre-paration of such dispersions o~ coating agents, which is characterised in that a cellulose ester, an alkyd resin and a plasticiser are dissolved in an organic solvent, this solution is dispersed into a solution consisting o~ emulsi~ier and water and the organic solvent is removed by distillation.
The size of the dispersed particles is particularly important for the stability of the di~persion and also ~or its behaviour in film formation. According to the invention it is preferably 0.1 to 0.5~ and it does not change substantially even on prolonged storage at 5-50C.
Cellulose esters which can be used in accordancs with the in~ention are, in particular, cellulose acetate, cellulose aoetobutyrate, cellulose acetate-benzoate and cellulose sorbate-acetate and mixtures of these esterq. Ni~rocellulose, for example the customary collodion cotton qualities, that is to 3ay cellulose nitric acid esters having a nitrogen content of ; 10.2 to 12.4% by weight, is more particularly suitable.
Plasticisers within the me~ing of the invention are, i~ particular, esters, such as dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dibutyl adipate, benzylbutyl adipate, dioctyl adipate, phosphoric acid esters, such as tri-cresyl phosphate, triphenyl phosphate or trioctyl phosphate, ~nd also benzenesulphonic aci~ N-methylamide.
Suitable alkyd resins are preferably oil-modified or ; ~atty acid-modified alkyd resins. Alkyd resins are under-stood a~ polyesters which are prepared from alcohol~ and carboxylic acids by polycondensation according to known pro-30l cesses and such as are defined; for ex~mple, in Ullmanns-Enzyklopadle der Teohnischen Chemie (Ullmann's Encyclopaedla 9~L
of Industrial Chemistry) or are described in D.R. Sol~mon, The Chemistry of Organic Filmformers, page 75-111. In general, the alcohols employed cantain 1 to 15, preferably 2 to 6, C atcms and the acids used, or their ester-formang derivatives, contain 2 to 14, preferably 4 to 12, C atoms. These alkyd resins can optionally be mixed with other polyesters, for example also with oil-free poly-esters.
Examples of suitable alcohols are pentaerythritol, glycerol, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol, 1,2,6-hexanetriol, ethylene glycol, propane-1,2-diol,propane-1,3-diol, butane-1,2-diol, butane-1,3-diol and butane-1,4-diol, neo-pentylglycol, diethylene glycol, triethylene glycol, dipropylene glycol, hexane-1,6-diol,1,2-bis-(hydroxymethyl)-cyclohexane and 1,4-bis-(hydroxymethyl)-cyclohexane, 2-ethylpropane-1,3-diol, 2-ethyl-hexane-1,3-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and adipic acid bis-ethylene glycol ester; benzyl alcohol, cyclohexanol and other monoalcohols having 1 to 6 C atoms. Preferred alcohols are gly oerol, trimethylolpropane, neopentylglycol and pentaerythri-tol.
The following carboxylic acids, or their ester-formLng derivatives, may be mentioned as examples of suitable ad d COmpOIl-ents: phthalic acid, isophthalic acid, terephthalic acid, tetra-hydrophthalic acid and hexcahydrophthalic acid, endomethylene-tetrahydrophthalic acid, succinic acid, adipic acid, sebacic acid, trimellitic acid, benzoic acid and their derivatives, such as, for example, p-tert.-butylbenzoic acid and hexahydrobenzoic acid.
Phthalic acid is the most customary.
In the alkyd resins which are employed for the coating emulsions according to the invention, the proportion of oil can be 5 to 50% by weight, calculated as triglyceride and relative 11~105al to the alkyd resin. The drying or non-drying fatty aciJs which generally contain 6 to 24 C atoms, can be employed either as such or in the form o~ their glycerol esters (triglycerides), Animal and vegetable oils, ~ats or fQtty acids~ such as, ~or example, coconut oil, groundnut oil, castor oil, olive oil, soya bean oil, linseed oil, cottonseed oil 9 sa~flower oil or safflower oil ~atty acids, dehydrated castor oil or castor oil fatty acid, mono-unsaturated ~atty acids, lard, tallow and train oils, tall oil fatty acid and synthetic fatty acids, ~ay be mentioned as being suitable.
Suitable emulsiflers are homopolymers and copolymers of vinyl alcohol, for example polyvinyl alcohols which are formed by hydrolysis of polyvinyl acetate and which are available commercially, for example under the de~ignation Polyviol 15 I W 25/240 and W 25/140. Hydrolysed copolymers of vinyl-pyrrolidone and vinyl acetate are also suitable.
The dispersions o~ coating agents of the invention pre-ferably contain alkyd resins having an oil content of 20 to 45%.
The coatings according to the in~ention can be produced by dissolving the alkyd resin, the cellulose ester and the plasticiser in a polar solvent which is not soluble in water9 and which can be removed by dis~illation from the emulsion to be ~ormed, combining the solution with an aqueous solution of the emulsifier and thus forming an oil-in-water emulsion by means of high shearing forces. The organic solvent is then removed by di~tillation, on ~ts own or in the form o~ an aqueous a~eotrope. Solvents ~hich are particularly suitable are alkyl acetates and alkyl propionates. The aqueous emulsion which remains can be diluted with more water or a suitable coalascing agent can be added to it. In the ~ollowing -~ Trac~
this will be designated a secondary emulsion.
One or more coalescing or aggregating agents can also be added to the dispersion in order to achieve a clear film of high gloss. Coalescing agents which form an azeotrope with the water are preferred here. It is then necessary to add to the dispersion sufficient coalescing agent so that -the azeotrope is first distilled o~ and, in addition, to add further ooalescing agent which ef~ects the aggregation of the particles. Possible coalescing agents are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene ~lycol monobutyl ether-acetate diethylene glycol, diethylene glycol monobutyl ether, diacetone alodhcl methylgly-col acetate, methyl amyl ketone and diisobutyl ketone.
The primary emulsion consisting of cellulose ester, alkyd resin, emul~ifier, plasticiser, water and organic ~olvent i~ produced in a commercially available device having an adcquately high peripheral speed of 5 to 50 m/second, prefer ably 10-30 m/~econd.
Examples are: Ultra-Tu~a ~type 45 of 10,000 revolutions per minute; Gaulin homogeniser, di~;sol~er and beadmillsO
The emul~i~ica~ion time in the Ultra-Tun~x~hould not ; be more than 2 minutes, since otherwlse too great an e~olution of heat takes place This time is adequate to produce small, spherical particle~ of Q1-1.5pr0~rably Q1-0.5/u Pro~th~
~ ltu~rts o~ the ultimate emulsion.
In a pre~erred embodime~, the aqueou~ coating composit~on~
contain add1tionally 4 - 40 par~s by w~ight o~ an urea and/or m~lamine re~inO
Ur~a a~d melami~e re~ln~ in thi~ context are art recognized conden5ation product~ o~ ur~a or melamine and ~ormaldehyde which ar~ made in an alkaline medium. They are 501uble in water and are add~d to the di~p~rsion~ in the Iorm OI aqueou~ ~olutions~ Their ef~ect is a cros~linking of the coatings obtained from the disper ~ions which improves their stabillty and gloss. Catalytic amounts of p-toluene sulfonic acid accelerate crosslinking.
A solution in ethyl acetate wa~ prepared from:
100 g of nitrocellulose chips containing approximately 12% of nitrogen, Standard Specification 24 E in accordance with DIN 53,179, consisting of 82% of collodion cotton and 18%
of dibu-tyl phthalate, 0 100 g of groundnut oil fatty acld alkyd resin having an oil content of 41~, and of ethyl acetate 500 g After stirring slowly for approximately 3 hours a clear solution was obtained which WR3 combined with 300 g o~
a 3% strength aqueous solution of polyvinyl alcohol (Polyviol W 25/140), whilst stirring slowly, The mixture was then dispersed for 2 mi~utes in an Ultra-Tur~ax~ -type 45 laboratory ~ disperser by raising the speed of rotation continuously to 10,000 revolutio~s per minute. The solvent is distilled o~f under reduced pressure. A primary emulsion having a ~olids content of 40% and a ~low viscosity oX 34 second~ in the DINcup No.4 is thus obtained, which was processed in Example and 30 ~ son example:
A dispersion was prepared as described in Example 1, exceptthat instead of the polyvin~l alcohol 300 g of ~n aqueous solution of a non-ionic fatty acid ester (emulsifier Emulpho~Y~EL of BASF) were used. This ga~e an emulsion 30 which wa~ stable for a short time and which ga~re an average size of 13~ in a determination of particle pattern.
A dispersion was prepared from:
100 g of groundnut oil fatty acid alkyd resin having an oil content of 41%) 100 g of nitrocellulose chips as in Example 1, and o~ ethyl acetate 500 g After stirring for 3 hours, a clear solution was obtained ~hich is combined with 500 g o~ a 2.5% strength solu-tionofpolyvlnylalcaohol (Polyviol W 25/140) in water. The procedure described under Dispersion 1 was then followed. A
primary emulsion with a solids content of approximately 29%
and a flow viscosity of 28 secondsin theDIN cup NoO 4is obtained .U3~
I Example 1 (Comparison) A lacquer of the following composition was prepared:
Groundnut oil fatty acid alkyd resin with 41% of oil, 60% strength solution in xylene 152 parts by weight ~I Collodion cotton (cellulose nitric ac:id ester 1 ~ontaining approximately 12% of nit;rogen), Standard Specification type 24 E, DIN
; 53,179, in the form of chips111 parts by weigh~
Dibutyl phthalate 8 parts by welght i Ethylene glycol monoethyl ether59 parts by weight 2S Bu~yl acetate 190 parts by weight Ethyl acetate 140 parts by weight Xylene 300 parts by weight Ethylglycol acetate40 parts by weight ~ The resulting lacquer exhibited a viscosity correspond-ing to a flow time of approximately 30 seconds, measured in accordance with DIN 53,211 (DIN cup No.4). The curing to give films and the assessment are described in Table 1.
- 8 - .
Example 2 A dispersion of the following composition was prepared:
Dispersion from Example 1, 40% strength in water 550 parts by weight 5 ~ibutyl phthalate 10 parts by weight Ethylene glycol monomethyl ether124 parts by weight Ethylglycol acetate 44 parts by weight 4-Methyl-4-hydroxypentan-2-one32 parts by weight Water 234 parts by weight Levelling agent (alkylbenzenesulphonate) 6 parts by weight The resulting dispersion exhibited a viscosity corres-ponding to a flow time of approximately 15 seconds, measured in accordance with DIN 53,211, g _ .
h q~ ~
U~ 0 U~ U~ ~
a~ ~ ~o o P u~
El ~ ~ ~4 ~1 ~ QO h X o 0 o r-l o ~
h ~C
a~
~ ~ 'Q
tn~ ~ o ~0 ~o o ~ ~ g~
o ~ Q ~ 0 r~
o a~ ~> ~ ~ 0 t~ ~ rl h ~3 o a~ o o 0 h ~ o ~C O O ~1 ~1 0 Il~ ~ V $~ ~
~ ~ ~ æ ~ :~ o ~Q
~0 ~H ~
a~ o o a~ o .. æ
~1 a) ~ o o o a~ h ~1 ~ ~
~ ~1 X 0-~1 ~
bD td ~ ~q h ~n ~ o ~ ~
u~ h ~ ~q ~0 oO ~
h ~J h $ ~ o~
h ~, r~ w h ,~
,s ~ h ~0 ~ o Q~ ~q 0 ~I h w ~ d w ~d ~ O o rl w 0 ~ O
+~ 1 ~ O O
:~ d a) ,1~ ,~ ~ ~ o ~ ~ ~ ; o ~ n o u~ ~ ~q o o !~ ~ o~ al O ~ h t-l C) V
h ~ O O ~1 a) ~
Le A 17 8~6 - 10 -
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An aqueous dispersion of a coating agent in which the dispersed particles have a size from 0.1 to 1.5,µ, comprising of 5 to 50 parts by weight of cellulose ester, 5 to 30 parts by weight of a plasticiser, 5 to 50 parts by weight of an alkyd resin, 30 to 135 parts by weight of water and 0.5 to 10 parts by weight of an emulsifier, in which the emulsifier is a vinyl alcohol homopolymer or copolymer and the alkyd resin is a short-oil alkyd resin containing 5 to 50% by weight of oil.
2. An aqueous dispersion accord mg to claim 1 in which the alkyd resin contains 20 to 45% by weight of oil.
3. An aqueous dispersion according to claim 1, in which the dispersed particles have a size from 0.1 to 0.5 µ.
4. An aqueous dispersion according to claim 2, in which the dispersed particles have a size from 0.1 to 0.5µ.
5. An aqueous dispersion according to claim 1, in which the cellulose ester is a nitrocellulose ester.
6. An aqueous dispersion according to claim 2, 3 or 4 in which the cellulose ester is a nitrocellulose ester.
7. A process for the preparation of an aqueous dispersion of coating agent as claimed in claim 1, in which the cellulose ester, alkyd resin and plasticiser are dissolved in an organic solvent, this solution is dispersed into a solution of the emulsifier in water and the organic solvent is removed by distillation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2703075.7 | 1977-01-26 | ||
| DE19772703075 DE2703075A1 (en) | 1977-01-26 | 1977-01-26 | AQUATIC COATING COMPOUNDS AND PROCESS FOR THEIR PRODUCTION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1121091A true CA1121091A (en) | 1982-03-30 |
Family
ID=5999556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000295556A Expired CA1121091A (en) | 1977-01-26 | 1978-01-24 | Aqueous coating agents and a process for their preparation |
Country Status (10)
| Country | Link |
|---|---|
| AT (1) | AT380265B (en) |
| BE (1) | BE863304A (en) |
| CA (1) | CA1121091A (en) |
| DE (1) | DE2703075A1 (en) |
| ES (1) | ES466312A1 (en) |
| FR (1) | FR2378832A1 (en) |
| GB (1) | GB1580506A (en) |
| IT (1) | IT1155786B (en) |
| NL (1) | NL169891C (en) |
| SE (1) | SE443990B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2966893D1 (en) * | 1978-10-02 | 1984-05-17 | Purdue Research Foundation | Foods and pharmaceutical coating composition, method of preparation and products so coated |
| DE2853578A1 (en) * | 1978-12-12 | 1980-07-03 | Bayer Ag | Aq. alkyd resin-nitrocellulose dispersions - giving glossy coatings on furniture, etc. |
-
1977
- 1977-01-26 DE DE19772703075 patent/DE2703075A1/en not_active Withdrawn
-
1978
- 1978-01-16 NL NLAANVRAGE7800513,A patent/NL169891C/en not_active IP Right Cessation
- 1978-01-24 AT AT0049678A patent/AT380265B/en not_active IP Right Cessation
- 1978-01-24 CA CA000295556A patent/CA1121091A/en not_active Expired
- 1978-01-24 GB GB2815/78A patent/GB1580506A/en not_active Expired
- 1978-01-24 IT IT47759/78A patent/IT1155786B/en active
- 1978-01-25 SE SE7800914A patent/SE443990B/en not_active IP Right Cessation
- 1978-01-25 ES ES466312A patent/ES466312A1/en not_active Expired
- 1978-01-25 BE BE184627A patent/BE863304A/en not_active IP Right Cessation
- 1978-01-26 FR FR7802223A patent/FR2378832A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| SE443990B (en) | 1986-03-17 |
| NL169891B (en) | 1982-04-01 |
| NL7800513A (en) | 1978-07-28 |
| AT380265B (en) | 1986-05-12 |
| NL169891C (en) | 1982-09-01 |
| IT7847759A0 (en) | 1978-01-24 |
| BE863304A (en) | 1978-07-25 |
| GB1580506A (en) | 1980-12-03 |
| ES466312A1 (en) | 1978-10-01 |
| ATA49678A (en) | 1985-09-15 |
| SE7800914L (en) | 1978-07-27 |
| IT1155786B (en) | 1987-01-28 |
| FR2378832A1 (en) | 1978-08-25 |
| DE2703075A1 (en) | 1978-07-27 |
| FR2378832B1 (en) | 1983-03-04 |
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