SE193710C1

SE193710C1 -

Info

Publication number: SE193710C1
Authority: SE
Publication date: 1964-01-01

Description

Uppfinnare: R J Sheppard Priorttet begard Iran den 14 november 1955 (USA) I den svenska patentskriften 182 655 beskrivs en av flera skikt besta.ende ytbehandling for metall, vilka skikt besta av en pigmenthaltig grundfarg i kontakt med metallen och ett tackskikt, bestkende av en pigmenthaltig metylmetakrylatlack. Dessutom beskrivs aven en for d:enna ytbehandling avsedd renoveringsgrundfarg, sorn skiljer sig fran tidigare kanda kompositioner genom att sam, tidigt besitta de viktiga egenskaperna att vara snabbtorkande yid rumstemperatur, fasta vãl saval pa blottad metall som pa ett eller flera tidigare pafOrda lackskikt, ge en yta, pa vii-ken ,ett tackskikt ay en metylmetakrylatlack faster väl, och som motstar a.vflagning och sprickbildning under normal anyandning. Inventor: RJ Sheppard Priorttet began Iran, 14 November 1955 (USA) Swedish patent specification 182 655 describes a multilayer surface treatment for metal, which layers consist of a pigment-containing primer in contact with the metal and a thank-you layer, consisting of a pigmented methyl methacrylate lacquer. In addition, a renovation primer intended for this surface treatment is also described, which differs from previously known compositions by simultaneously possessing the important properties of being quick-drying at room temperature, solid wells on exposed metal as on one or more previously applied lacquer layers. a surface, on the vii-ken, a thank-you layer ay a methyl methacrylate lacquer adheres well, and which resists flaking and cracking during normal breathing.

Ett speciellt syfte med foreliggande uppfinfling Or att astadkomma ett forbattrat, av flera skikt bestaende ytbehandling for metall, vilka best& av ett tackskikt ay naetylmetakryllatlack, varvid tackskiktets vidhaftning är sadan, att man kan dra full nytta av polymetylmetakrylatlackens utomordentliga hallbarhet under normal anvIndning utomhus. A special object of the present invention is to provide an improved, multilayer surface treatment for metal, which consists of a roof layer of ethyl methacrylate lacquer, the adhesion of the roof layer being such that one can take full advantage of the excellent durability of the polymethyl methacrylate lacquer during normal use.

Ett ytterligare syfte med uppfinningen Or att tillhandahalla en flytande overdragskomposition, som är lamplig for anyandning som mellanstrykningsfarg och/eller som en phbattrings- eller reparationsgrundfarg i det ovan beskrivna fardigstrykningssystemet. Med den enligt uppfinningen foreslagna ytbehandlingen erhaller man metallfOremal, sarskilt stalforemal, med ett hOrt, fastsittande hallbart och mot sprickbildning och avflagning bestandigt av flera skikt bestaende skyddsOverdrag med ett tackskikt av metylmetakrylatlack. A further object of the invention is to provide a liquid coating composition which is suitable for use as an intermediate coat and / or as a primer or repair primer in the finish coat system described above. With the surface treatment proposed according to the invention, a metal form, especially a steel form, is obtained with a hard, adherent durable and against cracking and flaking permanently consisting of several layers of protective coating with a roof layer of methyl methacrylate lacquer.

Enligt foreliggande uppfinning astadkommes en strykningsandamalsenlig enligt patent 182 655, kannetecknad av att pigment ingar Dupl. kl. 22 g: 6/03; 22 h: 3; 22k: i en mangd av minst 180 % av hela det organiska filmhildande materialets vikt. According to the present invention, there is provided an ironing composition according to patent 182 655, characterized in that pigments contain Dupl. at 22 g: 6/03; 22 h: 3; 22k: in an amount of at least 180% of the weight of the entire organic film-covering material.

I dessa flytande overdragskompositioner, maste det finnas tillrackligt mycket bindemedel narvarande for att h011a ihop pigmentet och for .att fasthalla det mot ytan. Nar pigmenthalten stiger till ett varde av inemot 400 %, narmar den sig den punkt, dar de onskade effekterna ej langre intrada. In these liquid coating compositions, there must be a sufficient amount of adhesive present to hold the pigment together and to hold it to the surface. When the pigment content rises to a value of close to 400%, it approaches the point where the desired effects are no longer intrada.

P0 delta salt liar man enligt uppfinningen funnit en laming av problemet med den daliga adhesionen mellan ett tfickskikt av metylmetakrylatlack on en grundad metall darigenom, att man direkt pa grundfargen fore paforandet av tackskiktet av metylmetakrylatlacken anbringar ett skikt av en mellanstrypningsfarg av det i foregaende stycke beskriyna slaget. En ,speciell fordel med derma nya mellanstrykningsfarg Or, att den ej behover vara torr, nar metylmetakyrlattackskiktet fores, dirs. detta kan anbringas endast agon minut efter det .att mellanstrykningsfargen paforts. According to the invention, the problem of the poor adhesion between a thick layer of methyl methacrylate lacquer and a primed metal has been found to be paralyzed by applying a layer of an intermediate lacquer paint of the type described above directly to the primer before applying the top coat of the methyl methacrylate lacquer. the battle. A special advantage of this new intermediate coat color is that it does not need to be dry when the methyl methacrylic attack layer is applied. this can be applied only one minute after the intermediate coat has been applied.

Salund'a erhaller man Oven en losning pa prohlemet att reparera, laga eller Ater fardigstryka en metallyta, som Or forsedd med eller skall horses med ett tackskikt av en metylmetakrylatiack, och som uppvisar en blottlagd metallyta eller en med grundfarg Overdragen yta av otillracklig filmtjocklek, darigenom att man pa ytan av den ovum beskrivna mellanstrykningsfargen eller reparationsgrundfargen anbringar en flytande metylmetakrylatiack och torkar denna. Salund'a also obtains a solution to the problem of repairing, repairing or re-finishing a metal surface, which Or is provided with or is to be hoisted with a roof layer of a methyl methacrylate coat, and which has an exposed metal surface or a primer coated surface of insufficient film thickness, by applying a liquid methyl methacrylate paint and drying it to the surface of the intermediate coating paint described above.

Uppfinningen skall i det foljande forklaras mera ingaende med ett antal utforingsexempel, i vilka de angivna procenthalterna, f orsavitt icke annat .anges, hanfora sig till vikten. The invention will be explained in more detail below with a number of exemplary embodiments, in which the stated percentages, unless otherwise indicated, refer to the weight.

Exempel 1. En Overdragskomposition, som uppfyllde fordringarna ph an mellartstryk- 2- - ningsfarg eller en reparationsgrundfarg enligt foreliggande uppfinning, framstalldes genom rivning av bestandsdelarna i den forsta portionen enligt nedanstaende recept i en sedvanlig fargkvarn, tills en slat dispersion er- varefter bestandsdelarna i den andra portionen tillblandades: Viktdelar Forsta portionen Xylen14,0 Shellack, 45 % losning i 96 % ace- tondenaturerad sprit13,3 1/2" nitrocellulosa av lackkvalitet (fuktad med isopropylalkohol, innehallande 65,3 % nitrocellu- losa)9,2 Titandioxid4,1 Permanentvitt35,7 Kimrok (carbon black)0,3 Polyvinylbutyraldehydharts1,1 Andra portionen Metylisobutylketon9,4 Metylisobutylkarbinol3,6 Isopropylalkohol7,3 Etylenglykol-monoetyleter- acetat 2,02,0 100,0 Del i den fOrsta portionen anvanda polyvinylbutyraldehydhartset utgjordes av »Vinylite» XYHL (Carbide ez Carbon Chemicals Co.) med en viskositet av 12-18 centipois matt pa en 6 % losning i metanol vid 20° C. Example 1. A coating composition which met the requirements of an intermediate coating or a repair primer according to the present invention was prepared by grating the ingredients in the first portion according to the following recipe in a conventional paint mill, until a smooth dispersion followed by the ingredients in the second portion was mixed: parts by weight First portion Xylene 14.0 Shel lacquer, 45% solution in 96% acetone-denatured spirit 13.3 1/2 "nitrocellulose of lacquer quality (moistened with isopropyl alcohol, containing 65.3% nitrocellulose) 9.2 Titanium dioxide4 , 1 Permanent white35.7 Carbon black (carbon black) 0.3 Polyvinyl butyraldehyde resin1,1 Second portion Methyl isobutyl ketone9,4 Methyl isobutyl carbinol3,6 Isopropyl alcohol7,3 Ethylene glycol monoethyl ether acetate 2,02,0 100,0 Part of the first portion used polyvinyl butyric acid Vinylite »XYHL (Carbide and Carbon Chemicals Co.) with a viscosity of 12-18 centipois matt on a 6% solution in methanol at 20 ° C.

I denna blandning bestod det organiska fihnbildande materialet av 45,8 % nitrocellulosa av lack-kvalitet, 45,8 % shellack och 8,4 polyvinylbutyraldehydharts. Pigmentet ingick i en mangd av 306 %, raknat pa hela det organiska filmbildande materialets vikt. In this mixture, the organic film-forming material consisted of 45.8% lacquer grade nitrocellulose, 45.8% shellac and 8.4 polyvinyl butyraldehyde resin. The pigment was present in an amount of 306%, based on the weight of the entire organic film-forming material.

Ytbehandlingar genomforda med komposition enligt exempel 1 i denna beskrivning samt kompositionerna enligt exemplen 1-7 i patentskriften 182 655, jamfordes med kanda ytbehandlingar bestaende av endast grandfarg och tackskikt, pa foljande generella satt: Dubbla uppsattningar av rena bilkarosseriplater - den ena uppsattningen for utomhusprovning och den andra for laboratorieprov- itingav vilka nagra voro obehandlade och andra behandlats med en rostskyddsblandning 1. ex. »Bonnderite», overdrogos forst med ett flertal valkanda och allmant inarhetade kommersiella grundfarger, exempelvis de som anges i patentskriften 182 655, och pa det i namnda patentskrift beskrivna sattet. Den undre halften av varje grundad plat overdrogs darefter med produkten enligt exempel 1 i denna beskrivning eller med flagon av produkterna enligt exemplen 1-7 i paten-Wulften 182 655, sa aft var och en av dessa produkter anbragtes pa en eller flera av de kon- ventionella grundfargerna. Darefter anbragtes ett tackskikt av en metylmetakrylatlack Over hela ytan av var och en av platarna. Denna lack utgjordes av en typisk metylmetakrylatlack, som fortunnats till lamplig sprutviskositet, i tillracklig mangd for att ge forma overdragsskikt med c:a 0,05 mm tjocklek. Platarna snabbtorkades darefter i 20 minuter vid 80° C for paskyndande av torkningen, som vid rumstemperatur eljest skulle ha erfordrat en tid av 16-24 timmar, varigenom torra, harda overdrag bildades. Metylmetakrylatlacken hade foljande sammansattning: Homopolymer av metyl- Viktdelar metakrylat 29,74 Dibutylftalat 11,93 Titandioxid 7,16 Kimrok 0,07 Ferritgult 0,98 Rod jarnoxid 0,12 Toluen 25,00 Xylen 20,00 100,00 Homopolymeren av metylmetakrylat i denna komposition hade en relativ viskositet av c:a 1,142. Detta varde beraknas ur formeln V = t/ti van i t = polymerlosningens utstromningstid tr= utstromningstiden for det i polymerlosningen anvanda lOsningsmedlet. Surface treatments carried out with a composition according to example 1 in this description and the compositions according to examples 1-7 in patent specification 182 655, were compared with known surface treatments consisting of only primer and top coat, in the following general way: Double sets of clean car body plates - one set for outdoor testing and the other for laboratory testing of which some were untreated and others were treated with a rust protection mixture 1. ex. "Bonnderite" is first overlaid with a number of elective and generally inherited commercial primary colors, such as those disclosed in U.S. Pat. The lower half of each primed plate was then coated with the product of Example 1 of this specification or with the flakes of the products of Examples 1-7 of Paten-Wulften 182 655, so that each of these products was applied to one or more of the cones. the conventional base colors. Then, a top layer of a methyl methacrylate varnish was applied over the entire surface of each of the plates. This lacquer consisted of a typical methyl methacrylate lacquer, which was thinned to a suitable spray viscosity, in a sufficient amount to give forming a coating layer with a thickness of about 0.05 mm. The plates were then flash dried for 20 minutes at 80 ° C to accelerate the drying, which at room temperature would otherwise have required a period of 16-24 hours, thereby forming dry, hard coatings. The methyl methacrylate lacquer had the following composition: Homopolymer of methyl- Weight parts methacrylate 29.74 Dibutyl phthalate 11.93 Titanium dioxide 7.16 Kimrok 0.07 Ferrite yellow 0.98 Red iron oxide 0.12 Toluene 25.00 Xylene 20.00 100.00 The homopolymer of methyl methacrylate in this composition had a relative viscosity of about 1,142. This value is calculated from the formula V = t / ti van in t = the outflow time of the polymer solution tr = the outflow time of the solvent used in the polymer solution.

Utstromningstiderna uppmattes enligt ASTM D-445-46T, meted B, varvid man sã.som den i namnda provningsforeskrift anvanda »oljan» anvande: A) en losning av 0,25 g polymetylmetakrylat i 50 ml etylendiklorid samt B) ett prov av den etylendiklorid, som anvants sasom losningsmedel for lacken. Bestamningarna utfordes vid 25° C i en modifierad Ost-wald-viskosimeter, serie 50. The effluent times were measured according to ASTM D-445-46T, method B, using as the "oil" used in the said test regulation: A) a solution of 0.25 g of polymethyl methacrylate in 50 ml of ethylene dichloride and B) a sample of the ethylene dichloride , which was used as a solvent for the paint. The determinations are challenged at 25 ° C in a modified Ost-wald viscometer, series 50.

Metylmetakrylatlacken trams-Landes genom rivning av pigmentet i narvaro av polymeren, tills en slat, homogen: dispersion erholls. Den ovre halften av varje plat representcrade en hand grundfarg med ett tackskikt av metylmetakrylat direkt Over gTundningen, och den undre halften representerade en ytbehandling eller fardigstrykning enligt uppfinningen, dvs. med tackskiktet och grundningen atskilda ON ett mellanskikt. The methyl methacrylate lacquer is trampled by tearing the pigment in the presence of the polymer until a smooth, homogeneous dispersion is obtained. The upper half of each plate represented a hand of primer with a thank-you layer of methyl methacrylate directly over the surface, and the lower half represented a surface treatment or finishing coat according to the invention, i.e. with the thank layer and the primer separated ON an intermediate layer.

De salunda overdragna stalplatarna hade godtagbara egenskaper betraffande utseende, glans och hardhet, och inga olikheter kunde synas mellan de ytor som overdragits med metylmetakrylatlack Over en kand grundning utan mellanskikt samt de ytor som forsetts med en ytbehandling enligt uppfinningen. The thus coated steel plates had acceptable properties regarding appearance, gloss and hardness, and no differences could be seen between the surfaces coated with methyl methacrylate lacquer over a bachelor primer without intermediate layers and the surfaces continued with a surface treatment according to the invention.

De ovre (icke mellanstrukna) och undre — —3 (mellanstrukna) halvorna av varje stalplat i den ena uppsattningen av platar undersoktes betraffande tackskiktets adhesion darige- nom att tva 50 mm spar i form av ett X skars ned till metallen vertikalt genom skiktet. En sjalvhaftande cellofanremsa pressades over X:et °eh drogs av med ett ryck, varigenom varierande mangder av ytbelaggningen avIfigsnades och det kunde iakttagas, hur varje skikt satt fast vid det underliggande skiktet. I samtliga fall kunde det konstate- ras, att det av metylmetakrylatlack hestaen- de tackskiktet, nar det anbragts direkt pa grundningen, taste daligt pa denna och var forhallandevis latt att avdraga hell °eh hal- let. Till skillnad daremot taste tackskiktet val pa vart och ett av mellanskikten, vilket ytt- rade sig i aft haftremsan antingen avlagsna- des utan att nagra delar av ytbelaggningen fastnat, eller att i de fall, da vissa delar av- skalades, adhesionen hade upphort pa ett slumpartat satt vid olika gransytor hos ytbelaggningen. The upper (non-intermediate) and lower - -3 (intermediate) halves of each steel plate in one set of plates were examined for the adhesion of the roofing layer by cutting two 50 mm grooves in the form of an X down to the metal vertically through the layer. A self-adhesive cellophane strip was pressed over the X and was pulled off with a jerk, whereby varying amounts of the coating were removed and it could be seen how each layer adhered to the underlying layer. In all cases it could be ascertained that the roofing layer of methyl methacrylate lacquer, when applied directly to the primer, treaded poorly on it and was relatively easy to peel off completely. In contrast, the roofing layer was selected on each of the intermediate layers, which was expressed in the back strip either being removed without any parts of the surface coating sticking, or that in cases where certain parts were peeled off, the adhesion had ceased. a random sitting at different spruce surfaces of the surface coating.

Dessa provningsresultat bekraftade den analoga iakttagelsen, att nyframstallda ytbe-. laggningar grundade pa metylmetatkrylat och innehallande em mellanstrykningsfarg enligt uppfinningen motstodo en mera hardhant be- handling an vad fillet var med liknande ytbelfiggningar, som ej innehollo flagon anellanstrykningsfarg. These test results confirmed the analogous observation that newly produced surface coatings. Coatings based on methyl methate acrylate and containing an intermediate coat of paint according to the invention resisted a more harsh treatment than the fillet with similar surface coatings, which did not contain flake or coat paint.

Dessa provningsresultat pa nyframstallda ytbelaggningar bekraftades ytterligare, nar den andra platuppsattningen underkastades vaderleksprovning i Florida i 8 manader eller langre tid. Under derma tid hade samtliga ytor, dar tackskiktet air metylmeta.krylatlac- ken anbragts direkt pa grundningen, visat sig bristfalliga, i det att vidhaftningen Indian tackskiktet och grundningen upphorde, hos nagra platar sã svarartat att det endast erfordracles ea att gnuggning eller borstning eller en kraftig luftstrom for att avlagsna tackskiktet. I samtliga fall forblev tackskiktet fastsittande, nar det anbragts pa ett mellanskikt i enlighet med foreliggande uppfinning. These test results on newly developed coatings were further confirmed when the second set of slabs was subjected to weather testing in Florida for 8 months or longer. During this time, all surfaces where the roofing layer air methylmeta.crylate lacquer was applied directly to the primer had proved to be deficient, in that the adhesion of the Indian roofing layer and the primer ceased, with some slabs being so black that only rubbing or brushing or a strong air flow to remove the roof layer. In all cases, the thanksgiving layer remained adherent when applied to an intermediate layer in accordance with the present invention.

Ay resultaten Iran de ovan beskrivna proven tram* klart, att ytbelaggnirtgar enligt fOreliggande uppfinning are vasentligt mera anvandbara an tidigare kanda belaggningar, icke endast redart frail borj an utan aver]: un- der lartgvarig anvandning utomhus, sasom fallet exempelvis ar med bilkarosser. In the results of the tests described above, it is clear that surface coatings according to the present invention are substantially more usable than previously known coatings, not only from scratch but also from outdoor use, as is the case with car bodies, for example.

Anvandbarheten hos overdragskompositionen enligt ovanstaende exempel 1 och Overdragskompositionerna .enligt .exempel 1-7 i patentskriften 182 655 vid reparation, lagning eller fornyad strykning demonstrerades genom att main efterliknade de olika betingelser, vilka i normalt bruk skulle erfordra reparation, pa provplatar, som fardigstrukits kom.plett med olika, av Ire skikt bestaende fardigstrykning, bestaende av de ovan angiv na grundfargerna, mellanstrykningsfargerna och tackskiktet. The applicability of the coating composition according to Example 1 above and the coating compositions according to Examples 1-7 of patent specification 182 655 during repair, repair or re-ironing was demonstrated by mimicking the various conditions which in normal use would require repair on test plates which were finished. .plett with different finishing coatings consisting of Ire layers, consisting of the above-mentioned basic colors, intermediate coat colors and the top coat.

I ett av fallen sandslipades en 58 eller 65 cm2 yta av del torra metylmetakrylattaa.skik- tet noggrant, sa att mellanskiktet frilades. 1 ett annat fall nedslipades saval tb.ckskiktet som meilanstrykningsskiktet, sã att grundfargen frilades. I ett tredje fall sandslipades samtliga tre skikt, sa att naetallytan frilades. I samtliga fall utfordes slipningen sá att skiktet, som omgav den centrala delen, minskade successivt i tjocklek, sd all inga plotsliga forandringar i tjockleken kunde markas. In one of the cases, a 58 or 65 cm 2 surface of some dry methyl methacrylate was sanded thoroughly, so that the intermediate layer was exposed. In another case, both the backing layer and the meilan coating layer were ground down so that the base color was exposed. In a third case, all three layers were sanded, so that the naetal surface was exposed. In all cases the grinding is challenged so that the layer surrounding the central part gradually decreases in thickness, so that no sudden changes in the thickness could be marked.

Over dragskompositionerna enligt exempel 1 i denna beskrivning och exemplen 1-7 i patentskriften 182 655 sprutades yid lamplig sprutviskositet pa de sandslipade ytorna med nagon overlappning av de oslipade ytorna. Etter c:a 5 min torkning pafordes ett tackskikt ay den ovan beskrivna metyhnetakylatlacken och torkades. The coating compositions of Example 1 of this specification and Examples 1-7 of U.S. Pat. No. 182,655 were sprayed by suitable spray viscosity on the sand-sanded surfaces with some overlap of the uncut surfaces. After about 5 minutes of drying, a thank-you layer was applied to the above-described methyl tacylate varnish and dried.

De reparerade ytorna provades pa adhesionen och vaderleksbestandigheten pa det tidigare beskrivna sattet. Air resultaten framgar, att dessa produkter taste val pa den frilagda metallytan och pa de sandslipade ytorna av grundfargen, mellanstrykningsfargen eller tackfargen. De pabattrade ytorna visade inga vasentliga avvikelser fran det omgivand.e ursprungliga tfickskiktet vad utseendet och kvaliteten betraffar. The repaired surfaces were tested for adhesion and weather resistance in the manner previously described. The air results show that these products make choices on the exposed metal surface and on the sand-sanded surfaces of the base color, the intermediate coat color or the tan color. The paved surfaces showed no significant deviations from the surrounding original tfick layer in terms of appearance and quality.

Kvaliteten och koncentrationerna av nitrocellulosan, shellacken, polyvinylbutyraldehydhartset, mjukningsmedlen, de filmbildande materialen och losningsmedien aro desamma som anges i patentskriften 182 655. The quality and concentrations of the nitrocellulose, shellac, polyvinyl butyraldehyde resin, plasticizers, film-forming materials and release media are the same as those disclosed in U.S. Patent No. 182,655.

Lampliga pigment for anvandning i Overdragskompositionerna enligt derma uppfinming innefatta de som anges i samma patentskrift. Emellertid bOr minst 10 %, raknat pa den totala viktert av det organiska filmbildande materialet, anvandas for att astadkomma tackkraft och filmhallfasthet. Framstallningskostnaderna mirtskas genom anvandning ay billiga pigment. Lamp pigments for use in the coating compositions of this invention include those set forth in the same patent specification. However, at least 10%, based on the total weight of the organic film-forming material, should be used to achieve gratitude and film durability. Manufacturing costs are mitigated by the use of inexpensive pigments.

De enligt uppfinningen anvanda overdragskompositionerna kunna anbringas medelst godtyckliga kanda metoder, I. ex. sprutning, doppning eller strykning, ehuru sprutning Or att foredra. De enskilda skiktens tjoalek Or ej -avgbrande, fiirutsatt att man a-nvander de normala granser som forekomma mom lackeringstekniken, t. ex. 13-ft per skikt. The coating compositions used according to the invention can be applied by any known method, e.g. spraying, dipping or ironing, although spraying Or to be preferred. The individual layers tjoalek Or ej -avgbrande, provided that one uses the normal boundaries that occur with the painting technique, e.g. 13-ft per layer.

Alldenstund mellanstrykningsfargerna och renoveringsgrundfargerna enligt derma uppfinning aro baserade pa lufttorkande material, Or den lampligaste rnetoden for deras torkning medelst normal avdunstning av de flyktiga bestandsdelarna vid rumstemperatur. Renoveringsgrundlacken kunna emellertid om sa onskas snabbtorkas eller ugnstorkas genom att man utsatter den overdragna ytan for en forhojd temperatur, t. ex. 65-95° C i 1--min. - .4— 193 7— Det bör framhallas, att den som tackskikt i den foregaende beskrivningen ang,ivna metylmetakrylatlackert• endast utgor ett representativt exempel pa ett stort flertal dylika Tacker, som kunna anvandas i den forbattrade ffirdigstrykningen enligt uppfinningen. Alla bestandsdelarna i namnda lack kunna varieras med avseende pa mingd och/eller sammansattning enligt gangse kanda mete-der. En lamplig homopolymer av metylmetakrylat anges speciellt. Lampliga sampolymerer innefatta sadana Indian metylmetakrylat och en mindre mangd, t. ex. 2-25 %, av ett annat clamed sampolymeriserbart material, t. ex. akryl- och metakrylsyra, alkylestrar av akrylsyra med 1-4 kolatomer i alkylkedjan, alkylestrar av metakrylsyra med 2-4 kolatomer i alkylkedjan, vinylacetat, akrylnitril och styren. En sardeles anvandbar sampolymer innehaller c:a 98 % metylmetakrylat och 2 % metakrylsyra. The intermediate coatings and renovation primers of the present invention are always based on air-drying materials, or the most suitable method for their drying by normal evaporation of the volatile constituents at room temperature. However, the renovation primer can, if desired, be quickly dried or oven dried by exposing the coated surface to an elevated temperature, e.g. 65-95 ° C for 1 - min. It should be emphasized that, as a thank-you layer in the foregoing description, the methyl methacrylate lacquer referred to above only constitutes a representative example of a large number of such tacks which can be used in the improved finishing according to the invention. All the constituents in the said lacquer can be varied with respect to quantity and / or composition according to customary methods. A suitable homopolymer of methyl methacrylate is specifically indicated. Suitable copolymers include such Indian methyl methacrylate and a minor amount, e.g. 2-25%, of another clamed copolymerizable material, e.g. acrylic and methacrylic acid, alkyl esters of acrylic acid having 1-4 carbon atoms in the alkyl chain, alkyl esters of methacrylic acid having 2-4 carbon atoms in the alkyl chain, vinyl acetate, acrylonitrile and styrene. A particularly useful copolymer contains about 98% methyl methacrylate and 2% methacrylic acid.

De foredragna polymererna for anvO.ndning i metylmetakrylatlacken ha en relativ viskositet mellan 1,117 och 1,196, bestamd enligt den tidigare beskrivna metoden, vilket motsvarar en beraknad molekyhikt av 55000105000, och tacklacker, som baseras pa sadana polymerer, beskrivas i patentskriften 170 773. En annan typ av tacklacker, som speciellt lampa sig for sprutning, beskrivs i patentskriften 171 262. The preferred polymers for use in the methyl methacrylate lacquer have a relative viscosity between 1.117 and 1.196, determined according to the previously described method, which corresponds to a calculated molecular weight of 55000105000, and roof lacquers based on such polymers are described in patent specification 170 773. Another type of roof varnishes, which are particularly suitable for spraying, are described in patent specification 171 262.

Trots att de nya Overdragskompositionerna enligt derma uppfinning angetts sasom renoverings- eller reparationsgrundlacker eller -farger, Or det uppenbart, att de tack yore sine, utomordentligt tillfredsstallande egenskaper ej Aro begrA.nsade därtill, utan att de om sâ onskas kunna anvandas som ursprunglig grundning for hela den metallyta som skall la&eras. Although the new coating compositions of this invention have been reported as renovation or repair primers or paints, it is apparent that, thanks to their extremely satisfactory properties, they are not limited thereto, but may, if desired, be used as an original primer for the entire metal surface to be laid.

Del är Oven uppenbart, att de enskilda skikten av de olika overdragskompositionerna ej behova paforas i en enda paforing, utan att de om sa onskas kunna paforas i tvâ eller flera skikt av ett och samma material. Part It is also obvious that the individual layers of the different coating compositions do not need to be paforas in a single paforing, but that they can, if desired, be paforas in two or more layers of one and the same material.

Claims

Patent claim:

Liquid coating composition for primer and intermediate coating purposes according to patent 182 655, characterized in that the pigment constitutes in an amount of at least 180% of the weight of the entire organic film-forming material.

Composition according to claim 1, characterized in that the pigment contains in an amount of 180-400% of the weight of the organic film-forming material.

Composition according to Claim 1 or 2, characterized in that the methyl methacrylate polymer in the methyl methacrylate lacquer has a relative viscosity of 1,117-1,196. Request publications: Patents [ran Great Britain 307 292.