CA1155579A - Method for preparing a two-component polyurethane lacquer atomisable from a pressurised container - Google Patents
Method for preparing a two-component polyurethane lacquer atomisable from a pressurised containerInfo
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- CA1155579A CA1155579A CA000367010A CA367010A CA1155579A CA 1155579 A CA1155579 A CA 1155579A CA 000367010 A CA000367010 A CA 000367010A CA 367010 A CA367010 A CA 367010A CA 1155579 A CA1155579 A CA 1155579A
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- pressurised container
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- prepolymer
- lacquer
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Abstract
METHOD FOR PREPARING A TWO-COMPONENT POLYURETHANE LACQUER ATOMISABLE FROM A PRESSURISED CONTAINER A method is described for the preparation of a two-component polyurethane lacquer which is atomisable from a pressurised container (e.g. an aerosol can), the lacquer consisting of (i) as basic lacquer components a hydroxyl group-containing copolymer of specified composition, dissolved in an organic solvent, which is contained together with a specified propellant in a first pressurised container and (ii) as hardener component, a polyisocyanate of specified NCO group content, dissolved in an organic solvent, which is contained together with a specified propellant in a second pressurised container. The ready for-use lacquer is obtained by transferring the contents of one pressurised container into the contents of the other pressurised container and mixing the two components together. The individual components in their separate pressurised containers are storage-stable for at least one year and the mixture of the two components is sprayable for a period of up to 2-3 days.
Description
5 5 ~ 9 METHOD FOR PREPARING A TWO-COMPONENT POLYURE m ANE
LACQUER ATOMISABLE FROM A PRESSURISED CONTAINER.
:
The invention concerns a method for the preparation of a two-component polyurethane lacquer atomisable from a pressurised container, the lacquer consisting of (i) a basic lacquer component in the form of a prepolymer containing hydroxyl groups which is dissolved in an organic solvent and is contained together with a propellant in a first pressurised container, and (ii) a hardener component on the basis of a polyisocyan-ate dissolved in an organic solvent which together with a propellant is contained in a second pressurisecl container, and the lac~uer being obtainable in ready-for-use form by transfer o~ one component from its pressurised container into the pressurised container o~ the second component and mixing the two components.
Two-component polyurethane lacquers are characterised by good weather resistance and chemical resistance, high mechanical resistance and good adhesion to the substrate. They are excellently suited, therefore, both for a first coat and as a repair lacquer and they can in the second case also ~e applied over old one-component coatings. High quality two-component polyure-thane lacquers have been applied up to the present time only with the spray gun; an aerosol product is not available. A two-component polyurethane adhesive is already known from US Patent 3343718, according to which 1 15~7~
a base component from adipic acid and hexane triol together with a propellant - propane - is contained in a irst pressurised container and a hardener component consisting of a polyisocyanate together with a propellant - a mixture of monofluorotrichloromethane and difluoro-dichloromethane - is contained in a second pressurised container, and the ready-for-use adhesive is obtained when one component is transferred from its pressurised container into th~ pressurised container of the second component and both components are mixed; however, this principle cannot be adapted as it stands to two-component polyurethane lacquers, such as are known ~or example from German Auslegeschrift 1247006. The prepolymers used as the basic lacquer components are poorly compatible with the common propellants such as monofluorotrichloromethane (Rll), difluorodichloromethane (R12~, propane, butane, etc.
In many cases before, but at the latest a~ter, the addition of the isocyanate hardenar, insoluble products are formed in the form of sludge or lumps, 50 that the lacquer can no longer be applied. Some prepolymers are known which are compatible with the common propellants, but these prepolymers give coating ~ilms whic do not have adequate surface hardness, chemical resistance and solvent resist-ance. All hitherto known attempts to make available two-component polyurethane lac~uers in pressurised containers,such as aerosol cans, have remained unsuccessful up to now, because both the individual components in separate press-urised containers as well as the mixture of the two comp-onents in a single aerosol can had an inadequate storage stability ~or all practical purposes.
Hence there was the problem o~ making available a two-component polyurethane lacquer which not only has good application and film properties such as good weather resistance, chemical resistance, resistance to mechanical stress, good adhesion to other polyurethane lacquers, insensitivity of the film towards atmospheric moisture a~
S well as traces of grease and oils, and rapid hardening to avoid dust s~ttlement~ but also i5 compatible with propel-lants, the components of which are capable of being stored for a long period of time separately in their own pressur-ised containers and which, after the two components have been mixed, has a storage stability adequate for practical use.
According to this invention this pro~lem has been solved with a method for the preparation of a two-component polyurethane lacquer in which a prepolymer comp-rising a copolymer containing 1 to 7 wt.~/o of hydroxylgroups based upon styrene, vinyltoluene, methacrylic acid esters and/or acrylic acid esters with 1 to 8 carbon atoms in the alcohol residue as well as hydroxyalkyl acrylates ; and/or hydroxyalkyl methacrylates with 2 to 4 carbon atoms in the alcohol residue, or mixtures of such copolymers, as the first component, which may contain also i.norganic and/
or organic pigments, flow agents, anti-settling agents, thixotropic agents, reaction accelerators~ matting agents : and other additives, is dissolved in an organic solvent and is filled together with a propellant into a first pres-surised container and in which furthermore a hardener based upon a polyisocyanate containing 10 to 25 wt.% ~C0 groups~
: . dissolved in an organic solvent, i9 filled a~ second comp-onent together with a propellant into a second pressurised container, and wherein for preparation of the ready-for-use lacquer the one component is transferred from its pressurised container into the pressurised container of the other component and mixed with the said other 1 1 5~5~9 component, characterised in that (i) for a prepolymer containing up to 2 wt.% hydroxyl groups there is used as propellant propane, butane, monofluorotrichloromethane, difluorodichloromethane~ dimethyl ether, nitrogen or mixt-ures thereof and for a prepolymer containing more than 2wt.% hydroxyl groups there is used as propellant dimethyl ether or a mixture of dimethyl ether, propane and/or butane, (ii) for the hardener, nitrogen is used as propel-lant, and (iii) the amounts of the prepolymer present in the first pressurised container and of the polyisocyanate present in the second pressurisad container are so propor-tioned that on combination of the two components a mixture results which contains 60 to 96 wt./~ prepolymer and 4 to 40 wt.~/o hardener.
Surprisingly it has been found that the two-component polyurethane lacquer-propellant com~inations defined above are stable for at least a year in respect of the basic lacquer component and the hardener component in separate pressurised containers, whilst the mixture of the two components in a single pressurised container is still sprayable after 2 to 3 days. In distinction from the state of the art, this substantial increase in the application time of the two-component aerosol-lacquers ensures their usefulness under all usual practical conditions.
The basic lacquer component contains as prepoly-mer a copolymer of styrene and/or vinyltoluene~ esters of methacrylic acid and/or acrylic acid with 1 ~o 8 carbon atoms in the alcohol residue as well as hydroxyalkyl acryl-ates and/or hydroxyalkyl methacrylates with 2 to 4 carbon atoms in the alcohol residue. Examples o such prepolymers are copolymers of:-1. Methyl methacrylate, ethyl methacrylate or iso-butyl methacrylate and hydroxyethyl or hydroxypropyl or 1 15;~5'~9 hydroxybutyl acrylate and/or the corresponding hydroxyalkyl methacrylates;
LACQUER ATOMISABLE FROM A PRESSURISED CONTAINER.
:
The invention concerns a method for the preparation of a two-component polyurethane lacquer atomisable from a pressurised container, the lacquer consisting of (i) a basic lacquer component in the form of a prepolymer containing hydroxyl groups which is dissolved in an organic solvent and is contained together with a propellant in a first pressurised container, and (ii) a hardener component on the basis of a polyisocyan-ate dissolved in an organic solvent which together with a propellant is contained in a second pressurisecl container, and the lac~uer being obtainable in ready-for-use form by transfer o~ one component from its pressurised container into the pressurised container o~ the second component and mixing the two components.
Two-component polyurethane lacquers are characterised by good weather resistance and chemical resistance, high mechanical resistance and good adhesion to the substrate. They are excellently suited, therefore, both for a first coat and as a repair lacquer and they can in the second case also ~e applied over old one-component coatings. High quality two-component polyure-thane lacquers have been applied up to the present time only with the spray gun; an aerosol product is not available. A two-component polyurethane adhesive is already known from US Patent 3343718, according to which 1 15~7~
a base component from adipic acid and hexane triol together with a propellant - propane - is contained in a irst pressurised container and a hardener component consisting of a polyisocyanate together with a propellant - a mixture of monofluorotrichloromethane and difluoro-dichloromethane - is contained in a second pressurised container, and the ready-for-use adhesive is obtained when one component is transferred from its pressurised container into th~ pressurised container of the second component and both components are mixed; however, this principle cannot be adapted as it stands to two-component polyurethane lacquers, such as are known ~or example from German Auslegeschrift 1247006. The prepolymers used as the basic lacquer components are poorly compatible with the common propellants such as monofluorotrichloromethane (Rll), difluorodichloromethane (R12~, propane, butane, etc.
In many cases before, but at the latest a~ter, the addition of the isocyanate hardenar, insoluble products are formed in the form of sludge or lumps, 50 that the lacquer can no longer be applied. Some prepolymers are known which are compatible with the common propellants, but these prepolymers give coating ~ilms whic do not have adequate surface hardness, chemical resistance and solvent resist-ance. All hitherto known attempts to make available two-component polyurethane lac~uers in pressurised containers,such as aerosol cans, have remained unsuccessful up to now, because both the individual components in separate press-urised containers as well as the mixture of the two comp-onents in a single aerosol can had an inadequate storage stability ~or all practical purposes.
Hence there was the problem o~ making available a two-component polyurethane lacquer which not only has good application and film properties such as good weather resistance, chemical resistance, resistance to mechanical stress, good adhesion to other polyurethane lacquers, insensitivity of the film towards atmospheric moisture a~
S well as traces of grease and oils, and rapid hardening to avoid dust s~ttlement~ but also i5 compatible with propel-lants, the components of which are capable of being stored for a long period of time separately in their own pressur-ised containers and which, after the two components have been mixed, has a storage stability adequate for practical use.
According to this invention this pro~lem has been solved with a method for the preparation of a two-component polyurethane lacquer in which a prepolymer comp-rising a copolymer containing 1 to 7 wt.~/o of hydroxylgroups based upon styrene, vinyltoluene, methacrylic acid esters and/or acrylic acid esters with 1 to 8 carbon atoms in the alcohol residue as well as hydroxyalkyl acrylates ; and/or hydroxyalkyl methacrylates with 2 to 4 carbon atoms in the alcohol residue, or mixtures of such copolymers, as the first component, which may contain also i.norganic and/
or organic pigments, flow agents, anti-settling agents, thixotropic agents, reaction accelerators~ matting agents : and other additives, is dissolved in an organic solvent and is filled together with a propellant into a first pres-surised container and in which furthermore a hardener based upon a polyisocyanate containing 10 to 25 wt.% ~C0 groups~
: . dissolved in an organic solvent, i9 filled a~ second comp-onent together with a propellant into a second pressurised container, and wherein for preparation of the ready-for-use lacquer the one component is transferred from its pressurised container into the pressurised container of the other component and mixed with the said other 1 1 5~5~9 component, characterised in that (i) for a prepolymer containing up to 2 wt.% hydroxyl groups there is used as propellant propane, butane, monofluorotrichloromethane, difluorodichloromethane~ dimethyl ether, nitrogen or mixt-ures thereof and for a prepolymer containing more than 2wt.% hydroxyl groups there is used as propellant dimethyl ether or a mixture of dimethyl ether, propane and/or butane, (ii) for the hardener, nitrogen is used as propel-lant, and (iii) the amounts of the prepolymer present in the first pressurised container and of the polyisocyanate present in the second pressurisad container are so propor-tioned that on combination of the two components a mixture results which contains 60 to 96 wt./~ prepolymer and 4 to 40 wt.~/o hardener.
Surprisingly it has been found that the two-component polyurethane lacquer-propellant com~inations defined above are stable for at least a year in respect of the basic lacquer component and the hardener component in separate pressurised containers, whilst the mixture of the two components in a single pressurised container is still sprayable after 2 to 3 days. In distinction from the state of the art, this substantial increase in the application time of the two-component aerosol-lacquers ensures their usefulness under all usual practical conditions.
The basic lacquer component contains as prepoly-mer a copolymer of styrene and/or vinyltoluene~ esters of methacrylic acid and/or acrylic acid with 1 ~o 8 carbon atoms in the alcohol residue as well as hydroxyalkyl acryl-ates and/or hydroxyalkyl methacrylates with 2 to 4 carbon atoms in the alcohol residue. Examples o such prepolymers are copolymers of:-1. Methyl methacrylate, ethyl methacrylate or iso-butyl methacrylate and hydroxyethyl or hydroxypropyl or 1 15;~5'~9 hydroxybutyl acrylate and/or the corresponding hydroxyalkyl methacrylates;
2. Styrene and hydroxyethyl or hydroxypropyl or hydroxybutyl acrylate and/or the corresponding hydroxy-alXyl methacrylates; and
3. Vinyltoluene and the hydroxyalkyl acrylates and/
or methacrylates mentioned in 2.
The components of the ccpolymers are selected in such a way that the final copolymer contains 1 to 7 wt . ~/o~
prefexably 1.3 to 6 wt.% of hydroxyl groups.
Frequently it is desirable to make the copolymers more "elastic" than is the case with the abova examples 1 to 3. For this purpose one can replace the so-called "hard"
monomers methyl methacrylate, styrene and vinyltoluene by up to 50 wt.% of methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. Such copolymers may for example have the following monomer composition:
40-60 wt.~ styrene, vinyltoluene or methyl methacryl~
ate.
lV-50 wt.% hy~roxyethyl acrylate, hydroxypropyl acrylate or the corresponding methacryl-ates; and 10-50 wt.% methyl acrylate, ethyl acrylate, butyl acrylate and~or 2-ethylhexyl acrylate.
The preparation of such copolymers is described in German Auslegeschrift 1247006.
; The prepolymer as a rule is dissolved in an organic solvent or solvent mixture. Suitable solvents are ~ 25 toluene, xylene, higher boiling aromatic hydrocarbons and ; their mixtures, acetic acid esters, ketones such as methyl-ethyl ketone or methylisobutyl ketone, ester ethers such as 2-methoxyethyl acetate and 2-ethoxyethyl acetate and mixtures o~ them. Methylisobutyl ketone and 2-ethoxyethyl acetats have proved to be especially advantageous solvents.
~ 1S~57'3 The concentration of the prepolymer in the solution depends upon the viscosity of the solution. The solution should not be too thin since then ~he film formation of the lacquer is inadequate and the lacquer readily sags : it should also, however, not be too viscous because then adequate atomis-ation is not achieved but more or less large drops are formed. In general a concentration of 50 to 60 wt.~h pre-polymer in the solution, or of 30 to 60 wt~% including the solvents from the lacquer recipe, gives a satisfactory application.
Inorganic or organic pigments may be dispersed in the solution of the prepolymer. Examples of inorganic pigments are titanium diox.ide, iron (III) oxide (iron oxide red), iron (II,III) oxide (iron oxide black), barium sulphate, lead chromate and silica; examples of organic pigments are phthalocyanines, Heliofast Black (Bayer AG), Permanent Yellow and Perrnanent Red. The pigments may be used singly or in the form of mixtures. The pigment content in the prepolymer solution may amo~nt to 20 to 45 wt.~/o.
In addition to pigments, the usual flow agents, anti-settling agents, thixotropic agents, accelerators, matting agents and other additives may be contained in the basic lacquer component.
The prepolymer solution forming the basic lacquer component, which may also contain the above-mentioned pigments and additives, is filled into an aerosol pressurised container in the form of a spray can, into which the propellant is introduced by known rnethods.
With prepolymers which contain 1 to 2 wt.~/o hydroxyl groups, propane, butane, monofluorotrichloromethane (Rll) difluorodichloromethane (R12), dimethyl ether, nitrogen or mixtures thereof are used as propellant; These :1 1 S ~ 5~ ~
propellants are also compatible with the reaction mixture of basic lacquer component and hardener component. If the prepolymer of the ba~ic lacquer component contains more than 2 wt./~hydroxyl groups, it is no longer compatible with all the propellants mentioned above : in this case, the best propellant is dimethyl ether. A mixture o~
dimethyl ether and propane/butane may also be used.
The filling ratio of the basic lacquer component to the propellant depends on the propellant selected and the viscosity of the mixture o~ prepoly~er and propellant.
The amount of propellant must be enough to ensure complete emptying of the lacquer from the aerosol can. As the basic lacquer component may consist of various prepolymers with different properties, and many combinations of propellants ; 15 are possible, no guids values can be given for the filling ratio of basic lacquer component and the particular propel-lant selectecl can be determined very quickly by simple ; spray tests.
The followin~ filling ratios serve as an indication:
30-70 wt. % basic lacquer component with 1 to 2 wt.%
hydroxyl groups 70-30 wt. % Rll/12-1090* or Rll/12-3070*
; 70-90 wt. % basic lacquer component with 1 to 2 wt.%
hydroxyl groups 30-10 wt. % propane J.
50-70 wt. % basic lacquer component with 1 to 2 ~, wt. % hydroxyl groups 50-30 wt. /9 propane-butane 10/85**
; 40-70 wt.o~ basic lacquer component with 1 to 7 wt.,~ hydroxyl groups ~;
60-30 wt.% dimethyl ether 1 155$79 20-60 wt.~ basic lacquer component with 1 to 7 wt.%
hydroxyl groups 40-Z0 wt.% propane-butane 15/85 **
40-20 wt.7~ dimethyl ether * The two first figures of the four-figure number givP
the percentage content of Rll, the two last figures give the percentage content of R12 in the propellant mixture.
** The number before the oblique ~ives the parts by weight o propane, the number after the obli~ue gives the parts by weight of butane in the propellant mixture.
The operating pressure with normal aerosol cans amounts to about 3 to 5 bar at 20C; this gives an average woxking pressure on atomisation of 2.5 to 3 bar.
The hardener component of the two-component poly-urethane lacquer consists o~ polyisocyanates contalning 10 to 25 wt.% isocyanate groups, dissolved in organic solvent~.
The polyfunctional isocyanates may be aliphatic or aromatic isocyanates. As hard~ner component, a reaction product of 3 mol. isophorone diisocyanate and 1 mol. trimethylol-propane with 15 to 16.5 wt~% NC0-~roups, a reaction product of 3 mol. toluylene diisocyanate and 1 mol. trimethylol-propane with about 17 wt.% of ~C0-groups, and an aliphatic triisocyanate containing biuret groups with about 21 wt.~/o ~C0-groups which is obtained by reaction of 3 mol. hexa-methylene diisocyanate with 1 mol~ water, have proved to be especially advantageous.
The polyfunctional isocyanate is dissolved in an organic solvent. Suitable solvents are glycol esters of acetic acid and aromatic hydrocarbons. The concentration of the isocyanate in the solvent amounts suitably to 11$~ 9 ~ g 50 to 75 wt~%. The isocyanate solution is filled into a pres~urised container e.g. a pressure can with an over-fl~w valve into which nitrogen is than filled as propel-lant gas. The filling ratio of isocyanate solution to nitrogen i~ not critical : the amount of nitrogen must be enough in order to empty the isocyanate solution from the pressurised container completely and to reach a final pressure which is higher than the ~illing pressure of the can containing the basic lacquer component. For normal pressure-atomiser cans, with a permi~sible internal press-ure of 20 bar at 50C, the pressure amounts to about 12 bar at 20C.
With the separate storage of the basic lacquer component and the hardener component in their separate cans, the components are storage-stable for about a year.
To obtain a ready-for-use lacquer the hardener component is transferred to the spray can containing the basic lacquer component. This filling is carried out by connecting the overflow valve of the pressurised container containing the hardener with a combined filling and atom-isation valve on the spray can containing the basic lacquer component. As the pressurised container containing the hardenex is at a higher pressure than is the case with the spray can containing the basic lacquer component, the nitrogen driv~s the hardenex solution into the spray can.
After completion of this filling the two lacquer compon-ents are mixed with one another by shaking the spray can.
The lacquer is then ready for use and can be sprayed~ The storage stability of the lacquer containing the hardener amounts to at least 24 hours, often 4~ to 72 hours.
The mixing ratio of the basic lacquer component to the hardener component is so selected that the ratio .... ~ . , ~t, 1 1 ~5~79 o the hydroxyl groups in the prepolymer to the NCO-groups in the polyfunctional isocyanate harden0r i9 in the range 1 : 0.8 to 1 : 1.25. Prepolymers which contain 1.3 to 4 wt.~/o OH-group~, and which are co~bined with a polyfunction-al isocyanate containing 10 to ~5 wt.% ~CO-groups in such amounts that for every OH-group there are 1.0 to 1.25 ~CO-groups, g~ve lacquers which yield films having good surface hardness and good resi~tance to solvents. If pre-polymers with 4.1 to 6 wt.% OH-groups are combined with polyfunc~ional isocyanates containing 10 to 25 wt.% ~CO-groups in such amounts that there are 1.0 to 1.25 NCO-yroups for each hydroxyl group, then lacquers are obtained which give films with good surface hardness, abrasion resistance and good resistance to chemicals.
In order to obtain a ready-for-use lacquer by simple mixing of the basic lacquex component with the hardener component in the spray can, the amount of the prepolymer in the spray can and the amount o~ isocyanate hardener present in the second pressure container are 50 ~o proportioned that on combining the two components a mixture is formed which contains 60 to 96 wt.% prepolymer contain-ing hydroxyl groups and 4 to 40 wt.% of polyfunctional isocyanate, both figures being based on the solids comp-osition of the mixture.
The coatings described dry after atomisation from the spray can to be assembly-resistant in about 90 to 100 minutes and they then crosslink at room temperature in one to seven days. Full strength properties are attained ater about seven days.
The lacquer films have good weather resistance and che~ica~ resistance which increase with increasing content of hydroxyl groups in the prepolymer~ They have a llS55~9 high degree of mechanical serviceability, have good adhesion on one- and two-component coatings and do not show, on application to one-component coatings, any lifting o~ these coatings. On application the two-compon-ent polyurethane lacquers are not sensitive to air currents, atmospheric moisture or traces of grease and oil on the substrate~ Since they dry rapidly, dirt formation due to dust is largely avoided~ No stringent requirements are placed on the pretreatment of the substrate : for old coatings it is good enough to rub down lightly and clean.
Due to the rapid drying, the good filling power and the freedom from sagging or running o~ the applied lacquer, many defects of the substrate are covered over.
The invention is illustrated by the following Examples but is not, however, limited thereby.
Two-component white, si~k aerosol lacquer.
Basic lacquer component The starting material for the basic lacquer component was a 6~/o solution in xylene and butyl acetate of a prepolymer of:-11 wt. /0 hydroxyethyl methacrylate 35 wt. % styrene 15 wt. % vinyltoluene Z5 19 wt. ~/0 butyl acrylate and 20 wt. ~0 2-ethylhexyl acrylate.
The 6~/o solution of the prepolymer contained 1.36 wt.% hydroxyl groups and a 50 % solution of the pre-polymer had a viscosity of about 90 ~ec efflux time, 30 measured in the DI~ cup with an efflux nozzle of 4mm diameter at 20C. 40 g of the 6~o solution was ground with 42 g o~ a pigment mixture of titanium dioxide and 1 1~5~79 barium ~ulphate on a roller mill, thinned with the solvent~ mentioned to a solids content of ca. 66 wt. %
and filled into the first spray can. Then an equal amount by weight o~ Rll/12-1090 as propellant was filled into the spray can. The product had a storage stability of at least one yearO
Hardener Component 7 g o a 67% solution of an aromatic triiso cyanate on the basis o 1 mol. trimethylolpropane and 3 mol. toluylene diisocyanate with a NC0-content of about 17 wt. %, based on the solvent-free product, in 2-ethoxy-ethyl acetate/xylene (1:1 by weight) was filled into a second pressurised container, which was then filled with nitrogen as propellant up to 10 to 12 bar pressure at 20C.
~rhe product had a storage stability of at least one year.
Two-component aerosol mixture The contents of the second pressurised container (hardener component) were emptied into the first pressur-ised container (spray can) and mixed with the basic lacquer 20 component by shaking. The mixture could be sprayed and applied satisfactorily ~or up to 72 hours after prepar-ation. It gave a white, silky lacquer film with all the propertie~ of a high quality two-component polyurethane lacquer.
Two-component yellow_oranqe~ qlossy a rosol lacquer asic lacquer component The starting material for the basic lacquer component was a 60~,h solution in 2-ethoxyethyl acetate of a prepolymer of:
11 wt. % hydroxyethyl methacrylate 35 wt. o/0 styrene 15 wt. % vinyltoluene 19 wt. ~0 butyl acrylate and 20 wt. % 2-ethylhexyl acrylate The 60% solution of the prepolymer contained 1.36 wt.% hydroxyl groups and a 5~/0 solution of the pre-polymer had a viscosity of about 90 sec efflux time, measured in the DI~ cup with an eflux nozzle of 4mm diameter at 20&. 46 g of the solution o the prepolymer was ground on a roller mill with a pigment mixture of Permanent Yellow, lead chromate and silica~ thinned with the give~ solvent to a solids content of about 55 wt.%
and filled into a spray can. The same amount by weight of Rll/12-3070 was filled in as propellant. The product was storage stable for at least one year~
Eardener component 11 g of a 75% solution of an aliphatic triiso-cyanate containing hiuret groups, which wasobtained by reaction of 3 mol. hexamethylene diisocyanate and 1 mol.
water and had a ~C0-content of about 21 wt.% based on the solvent-free product, was filled into a second pressurised container which was then filled up with nitrogen to a pressure of about 10 to 12 bar at 20C. The product was storage stable for at least one year~
Two-comPonen~ aerosoL mixture The contents of the second pressurised container were combinea with the basic lacquer component in th~
first pressurised container as in Exam~le 1. The mixture could be sprayed and applied satisfactorily for up to 72 hours after preparation. It gave a yellow-orange coloured glossy lacquer film with the propertie~ of a high quality two-component polyurethane lacquer.
1 ~5S5'~
1~ --In the preceding Examples low-crosslinking ; lacquers are descrihed. The ~ollowing Example3 illuskrat~
; high-crosslinking lacquers.
.
Two-compon~nt olive qreen, matt aerosol lacquer Basic lacquer _om~onent As prepolymer was used a copolymer of.
49 wt. % hydroxypropyl methacrylate 11 wt. % methyl methacrylate 40 wt. % styrene The 6~/o solution of the prepolymer contained 5.8 wt.% hydroxyl groups and a 5~/0 solution in 2-ethoxy-ethyl acetate had a viscosity of 160 sec measured in the DX~ cup with an efflux nozzle of 4 mm diameter at 20C.
34 ~ of the 6~/o solution o~ this prepolymer in 2~ethoxy-ethyl acetate was ground in a roller mill with 43 g o a pigment mixture o~ iron oxide red, iron oxide yellow, chromic oxide, Heliofast Black and barium sulphate, thinned with 23 g o the solvent mentioned and ~illed into a spray can. To 70 wt.% of this basic lacquer component;
30 wt.% of dimethyl ether was then added as propellant.
The storage stability of the prodùct amounted to at least one year.
Hardener com~onent The hardener component consisted of 20 g of a 7S% solution of ~n aliphatic triisocyanate containing biuret groups which is obtained by reaction o~ 3 mol.
hexamethylene diisocyanate and 1 mol. water and contains about 21% ~C0-groups. The hardener was contained with nitrogen as propellant in a second pressurised container with a filling pressure of about 10 to 12 bar at 20C and l 1S5~79 had a storage stability of at least one year.
Two-component aerosol mixture By combining the basic lacquer component and the hardener component in a spray can a lacquer was obtained which was sprayable at room ~emperature or up to 48 hours and gave a lacquer film with the properties of a two-component polyurethane lac~uer.
; ~ EX~MPLE 4 :
Two-component liqht ivory,_silk aervsol lacquer Basic lacquer component The prepolymer was obtained from:
49 wt.% hydroxypropyl methacrylate 11 wt.'~ methyl methacrylate and 40 wt.% styrene The 6~/o solution of the prepolymer contained 5.8 wt.~/o hydroxyl groups and a 50~/0 solution in 2-ethoxyethyl acetate had a viscosity of 160 sec measured in the DI~ cup with an ef1ux nozzle of 4 mm diameter at 20C. 40 g of the 60~ solution of this prepolymer in 2-ethoxyethyl acetate were ground in a roller mill with 36 g of a pigment mixture of titanium dioxide,iron oxide yellow, iron oxide red and barium sulphate. After thinning with 24 g of the given solvents 70 wt.% of the basic lacquer component and 30 wt.% of dimethyl ether as propellant were filled into a spray canO The product haa a storage stability of at least one year.
Hardener com~onent The hardener component consisted o 25 g o the product described in Example 3.
Two-component aerosol mixture The ready-~or-use lacquer was obtained as desc-rihed in Example 3 and could be applied for up to 48 hours.
1 15557g The lacquer film thus obtained had all the properties of a high quality two component polyurethane lacquer.
Two-component liqht green~ hiqh qloss aerosol lac~uer 54 g of a 6~/o solution of the prepolymer described in Example 4 in 2-ethoxyethyl acetate was ground with 21 g of a pigment mixture of titanium dioxide and phthalocyanine green on a roller mill, thinned with 25 g of the given solvents and ~illed into a spray can. To 70 wt.% of this basic lacquer component was added 30 wt.% of dimethyl ether as propellant. The mixture had a storage stability of at least one year.
As hardener was used the one described in Example 3 of which 33 g were filled lnto a second pressur-ised container with nitrogen as propellant.
The lacquer obtained by combining the two comp-onents in the spray can was sprayable at room temperature for up to 48 hours and gave lacquer films with all the properties of a high quality two-component polyurethane lacquer.
;:~
or methacrylates mentioned in 2.
The components of the ccpolymers are selected in such a way that the final copolymer contains 1 to 7 wt . ~/o~
prefexably 1.3 to 6 wt.% of hydroxyl groups.
Frequently it is desirable to make the copolymers more "elastic" than is the case with the abova examples 1 to 3. For this purpose one can replace the so-called "hard"
monomers methyl methacrylate, styrene and vinyltoluene by up to 50 wt.% of methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. Such copolymers may for example have the following monomer composition:
40-60 wt.~ styrene, vinyltoluene or methyl methacryl~
ate.
lV-50 wt.% hy~roxyethyl acrylate, hydroxypropyl acrylate or the corresponding methacryl-ates; and 10-50 wt.% methyl acrylate, ethyl acrylate, butyl acrylate and~or 2-ethylhexyl acrylate.
The preparation of such copolymers is described in German Auslegeschrift 1247006.
; The prepolymer as a rule is dissolved in an organic solvent or solvent mixture. Suitable solvents are ~ 25 toluene, xylene, higher boiling aromatic hydrocarbons and ; their mixtures, acetic acid esters, ketones such as methyl-ethyl ketone or methylisobutyl ketone, ester ethers such as 2-methoxyethyl acetate and 2-ethoxyethyl acetate and mixtures o~ them. Methylisobutyl ketone and 2-ethoxyethyl acetats have proved to be especially advantageous solvents.
~ 1S~57'3 The concentration of the prepolymer in the solution depends upon the viscosity of the solution. The solution should not be too thin since then ~he film formation of the lacquer is inadequate and the lacquer readily sags : it should also, however, not be too viscous because then adequate atomis-ation is not achieved but more or less large drops are formed. In general a concentration of 50 to 60 wt.~h pre-polymer in the solution, or of 30 to 60 wt~% including the solvents from the lacquer recipe, gives a satisfactory application.
Inorganic or organic pigments may be dispersed in the solution of the prepolymer. Examples of inorganic pigments are titanium diox.ide, iron (III) oxide (iron oxide red), iron (II,III) oxide (iron oxide black), barium sulphate, lead chromate and silica; examples of organic pigments are phthalocyanines, Heliofast Black (Bayer AG), Permanent Yellow and Perrnanent Red. The pigments may be used singly or in the form of mixtures. The pigment content in the prepolymer solution may amo~nt to 20 to 45 wt.~/o.
In addition to pigments, the usual flow agents, anti-settling agents, thixotropic agents, accelerators, matting agents and other additives may be contained in the basic lacquer component.
The prepolymer solution forming the basic lacquer component, which may also contain the above-mentioned pigments and additives, is filled into an aerosol pressurised container in the form of a spray can, into which the propellant is introduced by known rnethods.
With prepolymers which contain 1 to 2 wt.~/o hydroxyl groups, propane, butane, monofluorotrichloromethane (Rll) difluorodichloromethane (R12), dimethyl ether, nitrogen or mixtures thereof are used as propellant; These :1 1 S ~ 5~ ~
propellants are also compatible with the reaction mixture of basic lacquer component and hardener component. If the prepolymer of the ba~ic lacquer component contains more than 2 wt./~hydroxyl groups, it is no longer compatible with all the propellants mentioned above : in this case, the best propellant is dimethyl ether. A mixture o~
dimethyl ether and propane/butane may also be used.
The filling ratio of the basic lacquer component to the propellant depends on the propellant selected and the viscosity of the mixture o~ prepoly~er and propellant.
The amount of propellant must be enough to ensure complete emptying of the lacquer from the aerosol can. As the basic lacquer component may consist of various prepolymers with different properties, and many combinations of propellants ; 15 are possible, no guids values can be given for the filling ratio of basic lacquer component and the particular propel-lant selectecl can be determined very quickly by simple ; spray tests.
The followin~ filling ratios serve as an indication:
30-70 wt. % basic lacquer component with 1 to 2 wt.%
hydroxyl groups 70-30 wt. % Rll/12-1090* or Rll/12-3070*
; 70-90 wt. % basic lacquer component with 1 to 2 wt.%
hydroxyl groups 30-10 wt. % propane J.
50-70 wt. % basic lacquer component with 1 to 2 ~, wt. % hydroxyl groups 50-30 wt. /9 propane-butane 10/85**
; 40-70 wt.o~ basic lacquer component with 1 to 7 wt.,~ hydroxyl groups ~;
60-30 wt.% dimethyl ether 1 155$79 20-60 wt.~ basic lacquer component with 1 to 7 wt.%
hydroxyl groups 40-Z0 wt.% propane-butane 15/85 **
40-20 wt.7~ dimethyl ether * The two first figures of the four-figure number givP
the percentage content of Rll, the two last figures give the percentage content of R12 in the propellant mixture.
** The number before the oblique ~ives the parts by weight o propane, the number after the obli~ue gives the parts by weight of butane in the propellant mixture.
The operating pressure with normal aerosol cans amounts to about 3 to 5 bar at 20C; this gives an average woxking pressure on atomisation of 2.5 to 3 bar.
The hardener component of the two-component poly-urethane lacquer consists o~ polyisocyanates contalning 10 to 25 wt.% isocyanate groups, dissolved in organic solvent~.
The polyfunctional isocyanates may be aliphatic or aromatic isocyanates. As hard~ner component, a reaction product of 3 mol. isophorone diisocyanate and 1 mol. trimethylol-propane with 15 to 16.5 wt~% NC0-~roups, a reaction product of 3 mol. toluylene diisocyanate and 1 mol. trimethylol-propane with about 17 wt.% of ~C0-groups, and an aliphatic triisocyanate containing biuret groups with about 21 wt.~/o ~C0-groups which is obtained by reaction of 3 mol. hexa-methylene diisocyanate with 1 mol~ water, have proved to be especially advantageous.
The polyfunctional isocyanate is dissolved in an organic solvent. Suitable solvents are glycol esters of acetic acid and aromatic hydrocarbons. The concentration of the isocyanate in the solvent amounts suitably to 11$~ 9 ~ g 50 to 75 wt~%. The isocyanate solution is filled into a pres~urised container e.g. a pressure can with an over-fl~w valve into which nitrogen is than filled as propel-lant gas. The filling ratio of isocyanate solution to nitrogen i~ not critical : the amount of nitrogen must be enough in order to empty the isocyanate solution from the pressurised container completely and to reach a final pressure which is higher than the ~illing pressure of the can containing the basic lacquer component. For normal pressure-atomiser cans, with a permi~sible internal press-ure of 20 bar at 50C, the pressure amounts to about 12 bar at 20C.
With the separate storage of the basic lacquer component and the hardener component in their separate cans, the components are storage-stable for about a year.
To obtain a ready-for-use lacquer the hardener component is transferred to the spray can containing the basic lacquer component. This filling is carried out by connecting the overflow valve of the pressurised container containing the hardener with a combined filling and atom-isation valve on the spray can containing the basic lacquer component. As the pressurised container containing the hardenex is at a higher pressure than is the case with the spray can containing the basic lacquer component, the nitrogen driv~s the hardenex solution into the spray can.
After completion of this filling the two lacquer compon-ents are mixed with one another by shaking the spray can.
The lacquer is then ready for use and can be sprayed~ The storage stability of the lacquer containing the hardener amounts to at least 24 hours, often 4~ to 72 hours.
The mixing ratio of the basic lacquer component to the hardener component is so selected that the ratio .... ~ . , ~t, 1 1 ~5~79 o the hydroxyl groups in the prepolymer to the NCO-groups in the polyfunctional isocyanate harden0r i9 in the range 1 : 0.8 to 1 : 1.25. Prepolymers which contain 1.3 to 4 wt.~/o OH-group~, and which are co~bined with a polyfunction-al isocyanate containing 10 to ~5 wt.% ~CO-groups in such amounts that for every OH-group there are 1.0 to 1.25 ~CO-groups, g~ve lacquers which yield films having good surface hardness and good resi~tance to solvents. If pre-polymers with 4.1 to 6 wt.% OH-groups are combined with polyfunc~ional isocyanates containing 10 to 25 wt.% ~CO-groups in such amounts that there are 1.0 to 1.25 NCO-yroups for each hydroxyl group, then lacquers are obtained which give films with good surface hardness, abrasion resistance and good resistance to chemicals.
In order to obtain a ready-for-use lacquer by simple mixing of the basic lacquex component with the hardener component in the spray can, the amount of the prepolymer in the spray can and the amount o~ isocyanate hardener present in the second pressure container are 50 ~o proportioned that on combining the two components a mixture is formed which contains 60 to 96 wt.% prepolymer contain-ing hydroxyl groups and 4 to 40 wt.% of polyfunctional isocyanate, both figures being based on the solids comp-osition of the mixture.
The coatings described dry after atomisation from the spray can to be assembly-resistant in about 90 to 100 minutes and they then crosslink at room temperature in one to seven days. Full strength properties are attained ater about seven days.
The lacquer films have good weather resistance and che~ica~ resistance which increase with increasing content of hydroxyl groups in the prepolymer~ They have a llS55~9 high degree of mechanical serviceability, have good adhesion on one- and two-component coatings and do not show, on application to one-component coatings, any lifting o~ these coatings. On application the two-compon-ent polyurethane lacquers are not sensitive to air currents, atmospheric moisture or traces of grease and oil on the substrate~ Since they dry rapidly, dirt formation due to dust is largely avoided~ No stringent requirements are placed on the pretreatment of the substrate : for old coatings it is good enough to rub down lightly and clean.
Due to the rapid drying, the good filling power and the freedom from sagging or running o~ the applied lacquer, many defects of the substrate are covered over.
The invention is illustrated by the following Examples but is not, however, limited thereby.
Two-component white, si~k aerosol lacquer.
Basic lacquer component The starting material for the basic lacquer component was a 6~/o solution in xylene and butyl acetate of a prepolymer of:-11 wt. /0 hydroxyethyl methacrylate 35 wt. % styrene 15 wt. % vinyltoluene Z5 19 wt. ~/0 butyl acrylate and 20 wt. ~0 2-ethylhexyl acrylate.
The 6~/o solution of the prepolymer contained 1.36 wt.% hydroxyl groups and a 50 % solution of the pre-polymer had a viscosity of about 90 ~ec efflux time, 30 measured in the DI~ cup with an efflux nozzle of 4mm diameter at 20C. 40 g of the 6~o solution was ground with 42 g o~ a pigment mixture of titanium dioxide and 1 1~5~79 barium ~ulphate on a roller mill, thinned with the solvent~ mentioned to a solids content of ca. 66 wt. %
and filled into the first spray can. Then an equal amount by weight o~ Rll/12-1090 as propellant was filled into the spray can. The product had a storage stability of at least one yearO
Hardener Component 7 g o a 67% solution of an aromatic triiso cyanate on the basis o 1 mol. trimethylolpropane and 3 mol. toluylene diisocyanate with a NC0-content of about 17 wt. %, based on the solvent-free product, in 2-ethoxy-ethyl acetate/xylene (1:1 by weight) was filled into a second pressurised container, which was then filled with nitrogen as propellant up to 10 to 12 bar pressure at 20C.
~rhe product had a storage stability of at least one year.
Two-component aerosol mixture The contents of the second pressurised container (hardener component) were emptied into the first pressur-ised container (spray can) and mixed with the basic lacquer 20 component by shaking. The mixture could be sprayed and applied satisfactorily ~or up to 72 hours after prepar-ation. It gave a white, silky lacquer film with all the propertie~ of a high quality two-component polyurethane lacquer.
Two-component yellow_oranqe~ qlossy a rosol lacquer asic lacquer component The starting material for the basic lacquer component was a 60~,h solution in 2-ethoxyethyl acetate of a prepolymer of:
11 wt. % hydroxyethyl methacrylate 35 wt. o/0 styrene 15 wt. % vinyltoluene 19 wt. ~0 butyl acrylate and 20 wt. % 2-ethylhexyl acrylate The 60% solution of the prepolymer contained 1.36 wt.% hydroxyl groups and a 5~/0 solution of the pre-polymer had a viscosity of about 90 sec efflux time, measured in the DI~ cup with an eflux nozzle of 4mm diameter at 20&. 46 g of the solution o the prepolymer was ground on a roller mill with a pigment mixture of Permanent Yellow, lead chromate and silica~ thinned with the give~ solvent to a solids content of about 55 wt.%
and filled into a spray can. The same amount by weight of Rll/12-3070 was filled in as propellant. The product was storage stable for at least one year~
Eardener component 11 g of a 75% solution of an aliphatic triiso-cyanate containing hiuret groups, which wasobtained by reaction of 3 mol. hexamethylene diisocyanate and 1 mol.
water and had a ~C0-content of about 21 wt.% based on the solvent-free product, was filled into a second pressurised container which was then filled up with nitrogen to a pressure of about 10 to 12 bar at 20C. The product was storage stable for at least one year~
Two-comPonen~ aerosoL mixture The contents of the second pressurised container were combinea with the basic lacquer component in th~
first pressurised container as in Exam~le 1. The mixture could be sprayed and applied satisfactorily for up to 72 hours after preparation. It gave a yellow-orange coloured glossy lacquer film with the propertie~ of a high quality two-component polyurethane lacquer.
1 ~5S5'~
1~ --In the preceding Examples low-crosslinking ; lacquers are descrihed. The ~ollowing Example3 illuskrat~
; high-crosslinking lacquers.
.
Two-compon~nt olive qreen, matt aerosol lacquer Basic lacquer _om~onent As prepolymer was used a copolymer of.
49 wt. % hydroxypropyl methacrylate 11 wt. % methyl methacrylate 40 wt. % styrene The 6~/o solution of the prepolymer contained 5.8 wt.% hydroxyl groups and a 5~/0 solution in 2-ethoxy-ethyl acetate had a viscosity of 160 sec measured in the DX~ cup with an efflux nozzle of 4 mm diameter at 20C.
34 ~ of the 6~/o solution o~ this prepolymer in 2~ethoxy-ethyl acetate was ground in a roller mill with 43 g o a pigment mixture o~ iron oxide red, iron oxide yellow, chromic oxide, Heliofast Black and barium sulphate, thinned with 23 g o the solvent mentioned and ~illed into a spray can. To 70 wt.% of this basic lacquer component;
30 wt.% of dimethyl ether was then added as propellant.
The storage stability of the prodùct amounted to at least one year.
Hardener com~onent The hardener component consisted of 20 g of a 7S% solution of ~n aliphatic triisocyanate containing biuret groups which is obtained by reaction o~ 3 mol.
hexamethylene diisocyanate and 1 mol. water and contains about 21% ~C0-groups. The hardener was contained with nitrogen as propellant in a second pressurised container with a filling pressure of about 10 to 12 bar at 20C and l 1S5~79 had a storage stability of at least one year.
Two-component aerosol mixture By combining the basic lacquer component and the hardener component in a spray can a lacquer was obtained which was sprayable at room ~emperature or up to 48 hours and gave a lacquer film with the properties of a two-component polyurethane lac~uer.
; ~ EX~MPLE 4 :
Two-component liqht ivory,_silk aervsol lacquer Basic lacquer component The prepolymer was obtained from:
49 wt.% hydroxypropyl methacrylate 11 wt.'~ methyl methacrylate and 40 wt.% styrene The 6~/o solution of the prepolymer contained 5.8 wt.~/o hydroxyl groups and a 50~/0 solution in 2-ethoxyethyl acetate had a viscosity of 160 sec measured in the DI~ cup with an ef1ux nozzle of 4 mm diameter at 20C. 40 g of the 60~ solution of this prepolymer in 2-ethoxyethyl acetate were ground in a roller mill with 36 g of a pigment mixture of titanium dioxide,iron oxide yellow, iron oxide red and barium sulphate. After thinning with 24 g of the given solvents 70 wt.% of the basic lacquer component and 30 wt.% of dimethyl ether as propellant were filled into a spray canO The product haa a storage stability of at least one year.
Hardener com~onent The hardener component consisted o 25 g o the product described in Example 3.
Two-component aerosol mixture The ready-~or-use lacquer was obtained as desc-rihed in Example 3 and could be applied for up to 48 hours.
1 15557g The lacquer film thus obtained had all the properties of a high quality two component polyurethane lacquer.
Two-component liqht green~ hiqh qloss aerosol lac~uer 54 g of a 6~/o solution of the prepolymer described in Example 4 in 2-ethoxyethyl acetate was ground with 21 g of a pigment mixture of titanium dioxide and phthalocyanine green on a roller mill, thinned with 25 g of the given solvents and ~illed into a spray can. To 70 wt.% of this basic lacquer component was added 30 wt.% of dimethyl ether as propellant. The mixture had a storage stability of at least one year.
As hardener was used the one described in Example 3 of which 33 g were filled lnto a second pressur-ised container with nitrogen as propellant.
The lacquer obtained by combining the two comp-onents in the spray can was sprayable at room temperature for up to 48 hours and gave lacquer films with all the properties of a high quality two-component polyurethane lacquer.
;:~
Claims (8)
1. Method for the preparation of a product, atomisable from a pressurised atomising container, which is a two-component polyurethane lacquer in which a prepolymer comprising a copolymer containing 1 to 7 wt.% of hydroxyl groups based upon styrene, vinyl-toluene, methacrylic acid esters and/or acrylic acid esters with 1 to 8 carbon atoms in the alcohol residue as well as hydroxyalkyl acrylates and/or methacrylates with 2 to 4 carbon atoms in the alcohol residue, or mixtures of such copolymers, as the first component, which may contain also inorganic and/or organic pigments, flow agents, anti-settling agents, thixotropic agents, reaction accelerators, matting agents and other addit-ives, is dissolved in an organic solvent and is filled together with a propellant into a first pressurised container and in which furthermore a hardener based upon a polyisocyanate containing 10 to 25 wt% NCO
groups, dissolved in an organic solvent, is filled as second component together with a propellant into a second pressurised container, and wherein for prepar-ation of the ready-for-use lacquer the one component is transferred from its pressurised container into the pressurised container of the other component and mixed with the said other component, characterised in that (i) for a prepolymer containing up to 2 wt.% hydroxyl groups there is used as propellant propane, butane, monofluorotrichloromethane, difluorodichloromethane, dimethyl ether, nitrogen or mixtures thereof and for a prepolymer with more than 2 wt.% hydroxyl groups there is used as propellant dimethyl ether or a mixture of dimethyl ether, propane, and/or butane, (ii) for the hardener, nitrogen is used as propellant, and (iii) the amounts of the prepolymer present in the first pressurised container and of the polyisocyanate present in the second pressurised container are so proportioned that on combination of the two components a mixture results which contains 60 to 96 wt.% prepolymer and 4 to 40 wt.% hardener.
groups, dissolved in an organic solvent, is filled as second component together with a propellant into a second pressurised container, and wherein for prepar-ation of the ready-for-use lacquer the one component is transferred from its pressurised container into the pressurised container of the other component and mixed with the said other component, characterised in that (i) for a prepolymer containing up to 2 wt.% hydroxyl groups there is used as propellant propane, butane, monofluorotrichloromethane, difluorodichloromethane, dimethyl ether, nitrogen or mixtures thereof and for a prepolymer with more than 2 wt.% hydroxyl groups there is used as propellant dimethyl ether or a mixture of dimethyl ether, propane, and/or butane, (ii) for the hardener, nitrogen is used as propellant, and (iii) the amounts of the prepolymer present in the first pressurised container and of the polyisocyanate present in the second pressurised container are so proportioned that on combination of the two components a mixture results which contains 60 to 96 wt.% prepolymer and 4 to 40 wt.% hardener.
2. Method according to claim 1, characterised in that a dissolved prepolymer with up to 2 wt.% hydroxyl groups is filled into the first pressurised container in an amount of 30 to 70 wt.% of the total charge and as the rest of the charge is used monofluorotrichloromethane, difluorodichloromethane or a mixture of 10 to 30 wt.%
monofluorotrichloromethane and 90 to 70 wt.% difluoro-dichloromethane.
monofluorotrichloromethane and 90 to 70 wt.% difluoro-dichloromethane.
3. Method according to claim 1, characterised in that a dissolved prepolymer with up to 2 wt.% hydroxyl groups is filled into the first pressurised container in an amount of 70 to 90 wt.% of the total charge and the rest of the charge is propane.
4. Method according to claim 1, characterised in that a dissolved prepolymer with up to 2 wt.% hydroxyl groups is filled into the first pressurised container in an amount of 50 to 70 wt.% of the total charge and the rest of the charge is a mixture of 15 parts by weight propane and 85 parts by weight butane.
5. Method according to claim 1, characterised in that a dissolved prepolymer with up to 7 wt.% hydroxyl groups is filled into the first pressurised container in an amount of 40 to 60 wt.% of the total charge and the rest of the charge is dimethyl ether.
6. Method according to Claim 1, characterised in that a dissolved prepolymer with up to 7 wt.% hydroxyl groups is filled into -the first pressurised container in an amount of 20 to 60 wt.% of -the total charge, and the rest of the charge is a mixture of 15 parts by weight propane and 85 parts by weight butane in an amount of 40 to 20 wt.% of the total charge and also dimethyl ether in an amount of 40 to 20 wt.% of the total charge.
7. Method according to Claim 1, characterised in that the hardener is filled into the second pressurised container at such a pressure that the pressure in the second pressurised container is greater than the pressure in the first pressurised container containing the pre-polymer.
8. Method according to Claim 1, characterised in that the prepolymer is filled into the first pressurised container at such a pressure that the pressure in the first pressurised container amounts to 3 to 5 bar at 20°C and that the hardener is filled into the second pressurised container at such a pressure that the pressure in the second pressurised container amounts to 12 bar at 20°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000367010A CA1155579A (en) | 1980-12-17 | 1980-12-17 | Method for preparing a two-component polyurethane lacquer atomisable from a pressurised container |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000367010A CA1155579A (en) | 1980-12-17 | 1980-12-17 | Method for preparing a two-component polyurethane lacquer atomisable from a pressurised container |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155579A true CA1155579A (en) | 1983-10-18 |
Family
ID=4118729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000367010A Expired CA1155579A (en) | 1980-12-17 | 1980-12-17 | Method for preparing a two-component polyurethane lacquer atomisable from a pressurised container |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1155579A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988010283A1 (en) * | 1987-06-19 | 1988-12-29 | Battaglia Charles R | Antiglare coating |
| US5169558A (en) * | 1989-07-21 | 1992-12-08 | Fox Valley Systems, Inc. | Two-part aerosol composition for increasing the light reflectivity of an object |
-
1980
- 1980-12-17 CA CA000367010A patent/CA1155579A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1988010283A1 (en) * | 1987-06-19 | 1988-12-29 | Battaglia Charles R | Antiglare coating |
| US4806583A (en) * | 1987-06-19 | 1989-02-21 | Battaglia Charles R | Antiglare coating |
| US5169558A (en) * | 1989-07-21 | 1992-12-08 | Fox Valley Systems, Inc. | Two-part aerosol composition for increasing the light reflectivity of an object |
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