CA2163875A1 - Coating composition including a uv-deblockable basic catalyst - Google Patents
Coating composition including a uv-deblockable basic catalystInfo
- Publication number
- CA2163875A1 CA2163875A1 CA002163875A CA2163875A CA2163875A1 CA 2163875 A1 CA2163875 A1 CA 2163875A1 CA 002163875 A CA002163875 A CA 002163875A CA 2163875 A CA2163875 A CA 2163875A CA 2163875 A1 CA2163875 A1 CA 2163875A1
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- Prior art keywords
- coating composition
- basic catalyst
- composition according
- blocked
- activated
- Prior art date
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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
- C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Paints Or Removers (AREA)
Abstract
A coating composition is provided which is based upon (A) an activated unsaturated group-containing compound, (B) an activated CH
group-containing compound and (C) a basic catalyst, wherein the basic catalyst is blocked with an acidic compound whereby the so-blocked catalyst becomes unblocked under the influence of UV light. These coating compositions possess extended potlife, good curing speed, and a good balance of physical and mechanical properties making them especially well-suited for a variety of coatings uses such as in paint, impregnating, sealing and bonding compositions.
group-containing compound and (C) a basic catalyst, wherein the basic catalyst is blocked with an acidic compound whereby the so-blocked catalyst becomes unblocked under the influence of UV light. These coating compositions possess extended potlife, good curing speed, and a good balance of physical and mechanical properties making them especially well-suited for a variety of coatings uses such as in paint, impregnating, sealing and bonding compositions.
Description
~ ~o 94/~8~75 ~ 3 8 7 5 PCT~Pg4/01451 , _ ....
, Cc,ating 80moosltion ~ncluding a UV-Oeblockable 8asic Catalyst 8ac.k~round of he rnvention 5 Ihe present inventian relates ~enerally to coating comoositions ~ased upon (A) compounds containing activated unsaturated groups and ~8) compounds containing activated C~ groups.
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rhese compositions are, in general, known from d number or references incluciing US275~913, OE-PS-835~09, US4871822 (EP-A-016082a), US4602061, US44080I8, US42173g6 (G8-A-2~48gl3) and EP-A-04481',4, o. ~h,_h ar~ .nc^,rporl'ed ~y rcr^rcnce hcrein ~or lll ,urposes.
for example, US2759gl3 and US4871822 generally disclose a composition of the above type which may ~e cured at ambient and elevated .emperatures. More specirically, these references generally describe, ~s component (A), compounds containing at least ~o activated ethylenic double bonds and, as component (8), a wide varie~y of compounds including those containing at le~st t~o aclivated me~hylene and/or monosubstituted methylene groups.
US4602061 discloses a similar composition except that, as componen~
~8), are specifically mentioned malonic croup-containirg oligomeric and polymeric esters.
US440t3018 and US42173g6 again disclose similar composittons except that, as component (B), are specirically mentioned ~ceto~cetate groups-containing compounds.
rt is also known rrom these rererences, and in general, that components (A) and (8) can react rapidly in the presencQ or (C) a - c,asic catalys. via d Michael addition. for this reason, it has not generally been ?ossible to formu~ate one-pdcK coa~ings nased upon ~his comcination or components due to a too short potlil~e.
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, Cc,ating 80moosltion ~ncluding a UV-Oeblockable 8asic Catalyst 8ac.k~round of he rnvention 5 Ihe present inventian relates ~enerally to coating comoositions ~ased upon (A) compounds containing activated unsaturated groups and ~8) compounds containing activated C~ groups.
.
rhese compositions are, in general, known from d number or references incluciing US275~913, OE-PS-835~09, US4871822 (EP-A-016082a), US4602061, US44080I8, US42173g6 (G8-A-2~48gl3) and EP-A-04481',4, o. ~h,_h ar~ .nc^,rporl'ed ~y rcr^rcnce hcrein ~or lll ,urposes.
for example, US2759gl3 and US4871822 generally disclose a composition of the above type which may ~e cured at ambient and elevated .emperatures. More specirically, these references generally describe, ~s component (A), compounds containing at least ~o activated ethylenic double bonds and, as component (8), a wide varie~y of compounds including those containing at le~st t~o aclivated me~hylene and/or monosubstituted methylene groups.
US4602061 discloses a similar composition except that, as componen~
~8), are specifically mentioned malonic croup-containirg oligomeric and polymeric esters.
US440t3018 and US42173g6 again disclose similar composittons except that, as component (B), are specirically mentioned ~ceto~cetate groups-containing compounds.
rt is also known rrom these rererences, and in general, that components (A) and (8) can react rapidly in the presencQ or (C) a - c,asic catalys. via d Michael addition. for this reason, it has not generally been ?ossible to formu~ate one-pdcK coa~ings nased upon ~his comcination or components due to a too short potlil~e.
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, In addition, because such catalyst is basic it has a tendency to become deactivated in the presence of certain acidic additives (e.g., certain pigments) or when the composition is applied to substrates having an acidic nature. This effect can be overcome by increasing the amount of catalyst; however, an already short potlife may be further shortened. The potlife problem is further exacerbated by the use of elevated temperatures.
One alternative for overcoming this problem in thermosetting applications is described in aforementioned EP-A-0448154, in which the _ basic catalyst is blocked with a particular carboxylic acid which is volatile and/or undergoes decarboxylation under curing conditions.
While providing good results for elevated cure conditions, this system is not generally applicable at ambient temperatures. It is, therefore, difficult to utilize these systems for heat sensitive substrates such as wood and thermoplastic polymers, as well as in industrial and non-industrial applications like decorative coatings and refinish paints.
An ambient temperature alternative for the systems described in EP-A-0448154, therefore, would be desirable.
Summary of the Invention The present invention provides such an alternative by utilizing a system which is curable under the influence of UV light.
More specifically, the present invention relates to a coating composition comprising (A) an activated unsaturated group-containing compound, (B) an activated CH group-containing compound and (C) a basic catalyst, characterized in that the basic catalyst (C) is blocked with an acidic compound whereby the so-blocked catalyst becomes unblocked under the influence of UV light having a wavelength in the range from 250-500 nm.
~ ~ wo 91l~30~, 216 3 8 75 PCT~P94/014~1 ~ 3 , ~t snouid be n3~ed ;ha UV-de~loc!~2Di~ bdSi. ca-ilys~ ar~ n gener I
'<nown ~rom US~301186, US4369206, OF ~-2g403j3 and 0~-A-29403~Z, a "
"n,c,i ~ ;"~. J i !J U I d ~ I y i ~ I ~ O l 1 ' i J U; .i ~J S ' S
2^ ~~rc;~. rhe suitability or sucn blocked ca~lysts for ~s~ in ichc31 addi~ion curin~ caatina systems, howe~en, is no~ ~vicient fr~m ~ny of the a~ove-,~entioned disclosures.
- rhe cod~ing compositions in acc3rdanco ~ith the present invention ~r^
in gener~l suitable ror a varie ~ or C3d-illgs U525, '~or -x2mpl~, ~s ?ainc, impre~nating, sealing ~na oonding composi~ions. The~ are ~a -spec,ally suit-d ror us~ as semi-one ~ac~ ciecori~lYe coa.lngs ind ~s t cl3arc3d~s in nas2coatfclearcoat sys~ems ,~or reriniS,i ^oplic~.ions (e.g., for au~omotive r~~inishes~.
rhese coating composit'ons ,oossess ~x~ended potlire, good curing speed upan oxposure .o UV light (wavelength or 250- 00 nm), ~nd ~ gQod ~dlanC- OF pnysical ind mechanicai ?r~pert~es mak,ng them especiaily well ,uited '~~r the ~rorementioned uses.
Ihese ~nd other r~tur_s ~nd adYd~tdqes ,~ ~he ~resent i;nvention will be more readily unders.ood by those skilled in the ar. ,~rom a eading of he ,~ollowing detailed descrip.ion.
Oe~ail~d Oescriotion of the Pre erred ~moodiments As mentioned earlier, the coating compositions in acc~rdancs with the ares2nt invention ars has2d upan (A) ac~iYat-d unsaturated group-containing compounds, (~) ~cti~atsd C'.~ group-c~n.aining compounds and (C) a basic catalys., ~nich ~dS i C catalys. is oloc~sd in a manner more fully descri~ed below.
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-r~ D S~
_ wo ~4/2~075 94/~1451 ~A) Ac~ivated Unsa~urated Group-Conl~ining Compounds As ,uitable compounds containing activated unsaturated groups may generally be mentioned ethylenically unsaturated campounds in which the carbon-car~on double bond is 1c~iYated by a caroonyl group in ~he -sosition. As representative examples or such may be mentioned those compounds disclosed in pre~iously incor~orat-d US275~gl3 (see - especially column 6, line 35 througn column 7, line 45), 0-PS-835809 (ses especially column 3, lines L6-41), US4871822 (see especially column 2, line 14 ~hrougn column d, line 14), U54602061 (see especially column 3, line la through column 4, line !4), US4408018 (see ~specially column 2, lines 1~-68), US42173g6 (s2e especially column 1, line 60 through column 2, line 64) and 'P-A-044~154 (see especially page 2, line 53 througn page 3, line 78).
As a r^irst preterred example may be mentioned the (meth)acrylic esters of compounds containing 1-~ hydroxyl groups and 1-20 carbon atoms.
~nstead of or in addition to (meth)acrylic acid may oe used, 'or example, crotonic acid and cinncmic acid. rhese ^sters may optional~y contain hydroxyl groups. Especially preferred examples include hexane diol diacrylate, trimethylol propane triacrylate and pentaerythritol triacrylat~.
As a second preferred example may be mentioned polyesters oased upon maleic, fumaric andfor itaconic acid (and maleic and itaconic anhydride), and di- or polyvalent hydroxyl compounds, optionally including a monovalent hydroxyl and/or carboxyl compound.
As a third preferred example may be mentioned polyester and/or alkyd restns containing pendant activated unsatùrated groups. These include, for example, urethane (meth)acrylates obtained by reaction of a polyisocyanate with an hydroxyl group-containing (meth)acrylic ~ ester, e.g , ~n nydroxyalkyl es~^r or (metn)acrylic acid or a .omoound prepared by esrerirfication of d polyhydroxyl compound with less than a ~ n~n ~- -t ~ 2 1 ~ 3 8 7 ~ PcT~P9~lot4sl ,i, ~
stoichiometric amount or (meth)acrylic ac,d; polyether (meth)acr~lalas ob~aine~ by est2ri,^~cation or an hydroxyl group-cont~inin~ poTyerher ~ith (meth)acrylic acid; ~olyrunctional (meth)acrylates obtained by reaction of an hydroxyalkyl (me~h)acrylato ~ith a polycarooxylic acid and/or a polyamino resin; poly(meth)acrylales oblained by reac~ion Ol-(meth~acrylic acid ~ith an epoxy resin; and polyalkyimaleates ootainedby reac-ion or a monoalkylmdlea~e estar ~ith an epoxy resin and/ar dn hydroxy runctionaT oligomer or polymer.
'specially prererred of the ac-ivate~ unsaturateci ~roup-coniaining comoounds are the arorementione~ poly~meth)dcrylates obtained by the reaction or (merh)acrylic acid with an epoxy resin.
rt is also especially prererred that the acid value of the activated unsaturated group-containing compoùnds be about 2 or less.
As exemplified by the previously incorporated references, these and other activated unsaturated group-containing compounds, and their methods or production, are aenerally known to those ,killed in the art, and need no rurther explanation here.
(8) Activated C:t Group-Containing Comoounds As suitable compounds containing activated C~ groups may be mentioned a ~ide variety of compounds as ~enerally disclosed in preYiouJly i~c~rpor~ US48J1~22 (see especially column 4, lines 15-28), whicn compounds contain a methylene and/or monosubstituted methylene group in the ~-position to two activating groups such as, ror e,Yample, carbcnyl, cyano, sulfoxide and~or nitro groups. Prererred or these are compounds containing a methylene group in the ~-oosition to t~o carbonyl groups, such as malonate and~or acetoacetate group-containing compounds.
~w o 94~807s 2 1 ~ 3 ~ 7 5 PCTAE~94;01451 .. o .s pr~tarred examples of malonate ~roup-conldinin9 compounds may be menttoned malonic acid eslers dS disclosed in ~reviously incorDc US275~913 (see especially co~umn 8, lines i-~2), and malonate group-containing oligomeric and 30 lymeric compounds as disclosed in pr~viously incorporat3~ US4602061 (see especidlly column !, line ~0 nrousn coiumn Z, line 13). Preferred or these are the oligomeric and/or polymeric malonate group-containing compounds such as, for example, polyurethanes, poiyesters, Qolyacrylat~s, epoxy resins, polyamides and~polyvinyl resins containing malonate groups in the main chain, pendant or both.
0 ,.
~he malonate group-containing polyurethanes may be obtained, '~or example, by reacting a polyisocyanate with an hydroxyl group-containing ester or^ a polyol and malonic acid, or by ~slerific.~tion or ~ransesterification or an hydroxy .,^unctional polyurethane with malonic ~cid or d dialkylmalonate.
Ihe malonare group-containing polyesters may be obta.ined, for example, by the polycondensation of malonic acid, an al~yl malonic acid (such dS ethyl malonic dcid), ~ mono- or dialkyl escer of such a malonic 2Q acid, and/or the reaction product of a malonic ester and an alkyt (meth)acryldte, optionally with other di- or polyc~rboxylic acids;
with di- and/or higher functional hydroxy compounds; ~nd, optionally manofunctional hydroxy and/or carboxyl compounds.
rhe malonate group-containing epoxy esters may be obtained, for example, by esterifying an epoxy resin with malonic acid or a malonic monoester, or by transesterirication with d dialkyl malonate, optionally with other carboxylic acids and derivatives thereof.
rhe malonate group-containing polyamides may be obtained, for example, in the same manner as the polyesters, wherein at least a part of the - hydroxy compound is re~laced with a mono- and/or polyvalent orimary - and/or secondary amine.
~..`,ii ~r ~D :s - -~ o 94/2807~ 216 3 8 7 5 pcTrEp94lol4~l j 7 Other malonate group-cont~ning ~olymers may ~e obtained by the ;ransesterirication of an ~xc~ss of ~ dialkyl malonate with ~n hydroxy-runctional polymer such as, ror example, a ~inyl alcohol/slyrene copolymer. ~n this manner, d polymer with malonat~
group-containing side-chains may be rormed. Any eXcQs, dialkyl mdlonate may be removed under reduced pressur or, optionally, be used as a reactive solvent.
Use may also be made of these malonate group-cantdi-ning compounds in ~hich the malonic acid st.uctural uni- is cyclized, ror ~xamole, by formaldehyde, acetaldehyde, acetone or cyclonexanone.
~.specially prererred of the malonate group-containing compounds for use with the prQsent invenrion ar~ the malonate group-containing oligomeric esters, polyesters, polyurethanes and epaxy ester, L5 containing 2-1aO, more preferably 2-20, malonate groups per molecu~e.
~t is also especially prer~rred that such malonate group-containing comoounds have ~ numoer average molecular weight (~n) in the range of from about 25Q to about 300a, and ~n acid number or aoout 2 or less.
As preferred examples or ac~oacetate group-containing comoounds may oe mentioned acetoacQtic esters ~s disclosed in pr~v~ously incorsorat~d US27~9913 (see aspecia11y column 8, lines ~3-5~), ~iacetoacetate compounds as disclosed in prQviou~ly incorporat~
US42173g6 (see especially column 2, line 6- through column 3, .11ne 27), and acetoacetate group-containing oligomeric and polymeric comoounds as disclosed in pr~viou-ly incorporatcd US4408Ql~ ~se~
especially column 1, line ~1 througn column 2, line 6). Prererr^d o,~
these are the oligomeric and/or polymeric acetoacetal3 ~roup-containing compounds.
~uitable dc~toacetate group-containing oligomeric and polymeric compounds~ c~n be ootained, -,~or exampl~, rrom polyalconols and/or hydroxy-runc.ional polyether, polyester, polyacryldte, vinyl and epcxy ~ ;0 94~2807s 2 ~ 6 3 8 7 ~ PCT~P94/0145I
oliaomers and polymers by reaction ~ith diketene or ~ransesterification ~itn an dlkyl acetoac~rate. ~uch compounds may dlso be obtained by copolymerization or an ac_-o~cetat~ functional acrylic monomer ~ith other vinyl- and/or acrylic-,unctional monomerS.
~specially preterred of the acetoacetate ~roup-containing compounds for use with the present invention are the acetoacetate group-containing oligomers and polymers containing a~t least 2 acetoacetat~ groups. ~t is also especially prererred that such ~c~toacetat~ group-containing compounds should have an Mn in the range IO of from about 234 to about 30000, and in acid numoer of about 2 or less.
Compounds containing both malonate and acetoacetate groups in the same molecule are also suitable and can be obtained, for example, by a icnael reaction between a malonate functional polyester and an acetoac3tate functional acrylic comoound (e.g., acetoacetoxyothyl ~crylate). Additionally, physical mixtures of malonat~ and acetoacetate group-containing compounds are suitable.
Alkylacoroacetates can, in addition, be used as reactiYe diluents.
Optionally, the activated C~ aroups-containing compounds may be utilized in enamine form sucn as ciisclosed ïn EP~ 0420I33, wnicn i.
incorpora~_d by r~farence herein for dll purpo,~, . if u~ly ,.t f~rth.
Agail1 as exemplified by the previously incorporated references, these and other malonate and/or acetoaceta~e group-containing compounds, and their methods of production, lre generally known to those s~illed in the art, and need no further exp1anation here.
As meniioned earlier, the aroredescribed components (A) and ~8) react ~ith ~-~ch ather through a Michael addi~iQn, in ~hich the act~vat-d C;~
grouD of component ~8) adds to one -of the caroon atoms or the ~r.~
~ Yo 94/23a~3 2 1 6 ~ ~ 7 5 P~T~Pg41014~1 ac~ivated unsd~urat3d 9rouD OT camponent (A) Components (A) and (B~
ar~ prereraDly contained in the coatin~ compositions in an amounl such that the ratio ~f the numoer or aclivated C,Y groups to the numoer of activated unsaturated ~roups is in the ran~e of about a,25 to about 4,0, more preferably in the range o,~ aoout 0,~ to aoout 2,0.
(C) ~locked 8asic Cat~lysts As i~dicated earlierT the blocked basic catalysts suitaole for use ~ith the present coating compositions are blocked with an acidic compound, whereoy the so-blocked c~talyst becomes unblocked under the inrluence of UV light having d waYelen5th in the ran~e from 250-SOQ nm ~he bc~sic cq~Alyst f~^y c~p~.~ ~ n ~ ~
As suitable basic catalysts far the Michael addition of !5 components (A) and (8) may be mentioned a ~ide Yariety or well-~nown amine, ammonium and phosphane compounds.dis-lo,c~ n ~h_ pr^Yicusly nc~rporated rcfercnces;
As preferred amine catalysts may be mentioned those of the amtdine type, for exampTe, t3tramethyl guanidine, 1,4-dihydropyrimidines, 1,8-diaza-bicyclo~.4.0~undec-7-ene, 1,4-diaza-bicyclo[2.2.2]octane and 2-alkyl-N-alkyl imidazolines.
As preferred ammonium catalysts may be mentioned quaternary amntonium compounds, for example, quaternary ammonium hydroxides such as tetrabutyl ammonium hydroxide; quaternary ammonium alkoxides such as benzyltrimerhyl ammonium methoxide and dilauryldimethyl ammonium methoxide; and quaternary ammonium carbanions such as benzyltrimethyl ammonium acetyl acetate.
As prer'erred phosphane compounds may be mentioned thos~ disclosed in provi~u311 incorpcrat~d US4871822 (column 7~ line 48 tnhrou~h column 8, line 2), and particularly the tertiary pnosDhanes ~ 94~80~ 21 6 3 8 7 ~ PCT~P94l01151 iisclosed therein. As sDeci'ic preferred ~xamples may be mencioned tri,~hyciroxymethyl)phosphane, ~riphenylphospnane and .ris(p-tolyl)phosphane.
rhese basic catalysts (unolocked) ~re generally utilized in ; amounts ranging rrom abouc Q,05 wt~ to ~'aout 3,0 wt~, preferably rrom about 0,L wt~ to about 1,0 wt~, aased upon the combined weight of components (A) and (8~. -Suitable blocking agents ror these basic caralysts comprise ~cidic compounds select_d rram:
~a) ~-keto carboxylic acids, (b) aromatic or N-heterocyclic substituted fonmic, acetic and oxyacetic acids, and (c) halide compounds.
As rnentioned earlier, suitable ~-~eto carboxylic actd blocking agents are known ,~rom F~eYiou.ly ,ncorparated US43G1186 (column I
line 3~ througn column 2, line 58) and US43~g206 (column 1, line 36 through column 2, line 37). As prererred examples may be mentioned phenyl glyoxylic acid, I-naphtyl glyoxylic acid, pyruvic acid and benzylidiene pyruvic acid.
Suitable aromatic or N-heteracyclic substituted formic, acetic and oxyacetic acid blockin~ agents are known from previou.ly ~ , 3~ 3~-A-294~333 (page 7, line 15 through page 8, line i5). As preferred exampl~s may be mentioned phenyl acetic acid, !-naphtyl acetic acid and 9-anthracene carboxylic acld.
Suitable halide blocktng agents are generally known rrom 0~-A-2940332. Preferred are the anions chloride, bromide and iodtde. rhe halide blockinq agents, howeYer, are-in general less prererr3d because a low molecular. weiqht haloqenide m~y be released upon unblocking or the c~talyst.
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~ WO 94t2807~ 216 3 8 7 ~ PCT/EP94/01451 The acidic compound is preferably utilized in an amount of from about 10 to about 125, more preferably from about 25 to about 125, and especially from about 50 to about 100, equivalent percent required to neutralize the basic catalyst. Within these ratios, the potlife of the composition can be readily varied, for example, between ~ hour at 20C to more than 6 weeks at 50C.
The basic catalyst and blocking agent can be mixed in situ and added to the composition in quantities to result in the desired ratio as set forth above. Alternatively, a salt of the catalyst and blocking agent can be pre-prepared and added to the composition.
The curing of the above-described coating compositions is preferably carried out at ambient temperatures (e.g., 10-30C) under the influence of UV light of a wavelength 250-500 nm, which can be from a UV source or even daylight.
Depending upon the field of application, the coating compositions in accordance with the present invention may optionally contain one or more pigments, dyes and usual intermediary agents, additives and/or solvents. Examples of suitable inert organic solverts include esters, ketones aromatic and aliphatic hydrocarbons. Examples of suitable reactive organic solvents include dimethyl malonate, diethyl malonate, ethyl acetoacetate and 2-ethylhexyl acrylate.
As examples of preferred additives may may be mentioned minor amount:s of a co-binder not containing activated unsaturated or CH
groups, for example, cellulose acetate butyrate, acrylic, epoxy and polyester resins. As is known to one skilled in the art, these co-binders are commonly utilized in the coatings industry to modify certain properties such as drying speed and adhesion to substrates.
12 C A2 163~75 As another preferred additive may be mentioned a UV sensitizer, such as anthracene, which is used to increase the amount of UV light absorbed by the coating 5 composition.
As mentioned earlier, the coating compositions in accordance with the presen invention are suitable for a variety of coatings uses, for example, as paint, impregnating, sealing and bonding compositions. A preferred application is as a semi 10 one-pack decorative coating.
Another preferred application is as a clearcoat in a basecoat/clearcoat system for refinish applications (e.g., automobile refinish). Suitable basecoats for us in such systems are in general well-known in the art. In the method of coating a substrate 15 with a basecoat/clearcoat system, the method comprises applying the basecoat onto the substrate, applying the clearcoat over the basecoat and curing the clearcoat at least in part by expos to UV light. These coating compositions may be applied to a substrate in any convenient manner such as, for example, by brushing, spraying or dipping. Suitable substrates include metals, wood, board, plastics and leather.
The foregoing more general discussion of the present invention will be further illustrated by the following specific examples.
EXAM PLES
(A) Preparation of Activated Unsaturated Group-Containing Compounds (A1 ) Into a reactor were added 1750,0 parts by weight (pbw) of xylene, which were heated.to boiling temperature. Next was added, over a period of three hours, a 30 mixture of 1400,0 pbw of glycidyl methacrylate, 1 935,5 pbw of styrene, 164,5 pbw of butyl acrylate, and -- 2i~387~
186,5 pbw of tert.butyl peroxy-3,5,5-trimethylhexanoate (commercially available under the trade designation Trigonox 42S from Akzo Chemicals), and thereafter an additional 194,0 pbw xylene. The reaction mixture was kept at boiling temperature until a conversion of at least 98% was achieved.
To this first reaction product was added 645,5 pbw of acrylic acid, 6,0 pbw of hydrochinone monomethylether and 1,5 pbw of chromium(III) 2-ethylhexanoate (commercially available under the trade designation Cordova AMC-2 from Cordova Chemicals), and this mixture was reacted at 120C under throughput of air until the acid value had decreased below 1.
After addition of 1361,0 pbw of xylene and 367,0 pbw of n-butanol, a 53,2 wt% polymer solution was obtained with a viscosity of 85,7 cPa.s at 20C, a color of 250 Apha, an acid value of o,1 and an Mn of 3580.
(A2) Into a five liter reaction vessel equipped with a thermometer, stirrer, air sparge and condensor, were charged 1445,6 pbw of isophorone diisocyanate, 160,9 pbw of dry methyl isobutyl ketone, 1,4 pbw of dibutyltin dilaurate and 0,9 pbw of 2,6-di-tert.butyl p-cresol (commercially available under the trade designation Ionol CP from Shell). After heating the mixture under stirring to a temperature of 60C, 1432,6 pbw of 2-hydroxyethylacrylate were added continuously over a period of one hour while a maximum temperature of 65C was maintained by cooling. Subsequently, 0,7 pbw of dibutyltin dialurate dissolved in 6,3 pbw of dry methyl isobutyl ketone were added dropwise over a period of ten minutes, followed by another 420,8 pbw of dry methyl isobutyl ketone.
WO 94/2807~; PCT/EP94/01451 2~6387S
The reaction mixture was thereafter maintained at 65C for four hours, after which the ~CO content of the remaining solution was about 0,5%. 192,4 pbw of n-butanol were then added, and the reaction mixture maintained at 65C until an NCO content of less than 0,1% was achieved (about another two hours).
After cooling to room temperature, an almost colorless solution of a urethane diacrylate was obtained with a non-volatiles content of 79,3% and a viscosity of 900 mPa.s.
(B) Preparation of Activated CH Group-Containing Compounds (B1) In a reactor, 560,0 pbw of Solvesso 100 were heated to a temperature of 160C. Subsequently, over a period of three hours, there was added a mixture of 1336,4 pbw of acetoacetoxyethylmethacrylate, 113,2 pbw of butylacrylate and 550,4 pbw of styrene. Separately from the monomer mixture there was added, over a period of three hours and fifteen minutes, a mixture of 200,0 pbw of Solvesso 100 and 200,0 pbw of Trigonox 42S.
After addition of the peroxide solution, the reaction mixture was cooled to 140C and an additional peroxide solution of 50,0 pbw of Solvesso 100 and 10,0 pbw of Trigonox 42S was added.
Subsequently, after 30 and 60 minutes, further peroxide solutions of 10,0 pbw of Solvesso 100 and 10,0 pbw of Trigonox 42S were added.
After an additional two hours of reaction, the mixture was cooled. Obtained was a polyacetoacetate resin solution with a viscosity of 117 cPas and a solids content of 66,7~. The polyacetoacetate resin possessed an acid number of 2, a theoretical acetoacetate number of 175 and a number average molecular weight (via GPC) of 1270.
~ w o 94/28075 2 1 6 3 8 7 ~ PCT~EP94/014s1 (C)Preparation of Blocked Catalysts (C1) To a solution of 35,5 grams of phenylglyoxylic acid in 150,0 grams tetrahydrofuran were added dropwise 36,0 grams of 1,8-diaza-bicyclo[5.4.0]undec-7-ene. After stirring for thrity minutes, the salt was isolated by evaporation of the solvent.
The recovered salt was purified by means of recrystallization from a solution in 40 ml tetrahydrofuran, yielding a pale yellow salt in a yield of about 67%.
(C2) lhe procedure of (C1) was repeated, except that the phenyl glyoxylic acid was replaced with 52,5 grams of 9-anthracene carboxylic acid.
Example l and Comparative Example 1 A coating composition was prepared from 30,0 grams of (Al), 16,5 grams of (Bl), 3,4 grams of butylacetate and 9,8 grams of a 10%
solution of (C1) in a mixture of butylacetate/methanol (87,5/12,5).
As a comparison, the same coating composition was formulated but instead of the solution of (C1) was utilized 4,9 grams of a 10%
solution of 1,8-diaza-bicyclo~5.4.0]undec-7-ene (DBU) in butylacetate.
These compositions were tested for geltime by storing 100 grams of the reaction mi-xture in a closed tin at a temperature as set forth below. The geltime is reported as the time when the mixture no longer flowed as a liquid upon stirring with a spatula.
Further, both compositions were applied onto a tin plated steel panel with a drawbar to a dry layer thickness of ca. 50~m.
~2~63~75 The panel of Example 1 was irradiated with a 400 Watt mercury lamp at a distance of 38 cm. The panel of Comparative Example 1 was not irradiated.
The petrol resistance of the so-applied coatings was tested qualitatively. After one week cure at 23C a drop of petrol was applied to the test panel. After five minutes, the panel was inspected for coating softening.
The pendulum hardness of the so-applied coatings was also tested after one day and one week cure at 23C with the aid of a Persoz apparatus.
The following results were obtained:
Petrol Persoz Hard. Dry Layer Geltime Resist. 1 day 1 week Thickness Example 1 >1 week at 50C O.K. 35" 137" 51~m Comp. Examp.l 10 min. at 20C O.K. 31" 115" 57~m Example 2 and Comparative Example Z
Example 1 was repeated except that 25 grams of (A2), 33 grams of (B1) and 13,4 grams of the 10% solution of (Cl) were utilized.
Comparative Example 1 was also repeated except that 6,75 grams of the 10% solution of DBU was utilized.
~WO 94/28075 2 1~ 3 ~ 7 ~ PCT/EP94/01451 The following results were obtained:
Petrol Persoz Hard. Dry Layer GeltimeResist. 1 day 1 week Thickness Example 2 ~10 days at 50Cgood 123" 249" 45~m Comp. Examp.2 22 min. at 20Cgood 140" 232" 48~m Example 3 and Comparative Example 3 The composition of Example 1 was repeated except that the solution of (C1) was replaced with 12,1 grams of a 10% solution of (C2) in a mixture of butylacetate/methanol (87,5/12,5).
This composition and the composition of Comparative Example 1 were applied onto a tin plated steel panel with a drawbar to a dry film thickness of ca. 80 ~m. For each composition two panels were prepared. One of each was exposed to daylight, while the other was stored in darkness. The petrol resistance and pendulum hardness were measured as above.
The following results were obtained:
Petrol Persoz Hard. Dry Layer Resist. 1 day 1 week Thickness Example 3 - light O.K. 12" 116" 86~m Example 3 - dark N.O.K. no curing ----Comp. Examp.3 -lightO.K. 21" 130" 78~m Comp. Examp.3 - darkO.K. 20" 128" 82~m
, In addition, because such catalyst is basic it has a tendency to become deactivated in the presence of certain acidic additives (e.g., certain pigments) or when the composition is applied to substrates having an acidic nature. This effect can be overcome by increasing the amount of catalyst; however, an already short potlife may be further shortened. The potlife problem is further exacerbated by the use of elevated temperatures.
One alternative for overcoming this problem in thermosetting applications is described in aforementioned EP-A-0448154, in which the _ basic catalyst is blocked with a particular carboxylic acid which is volatile and/or undergoes decarboxylation under curing conditions.
While providing good results for elevated cure conditions, this system is not generally applicable at ambient temperatures. It is, therefore, difficult to utilize these systems for heat sensitive substrates such as wood and thermoplastic polymers, as well as in industrial and non-industrial applications like decorative coatings and refinish paints.
An ambient temperature alternative for the systems described in EP-A-0448154, therefore, would be desirable.
Summary of the Invention The present invention provides such an alternative by utilizing a system which is curable under the influence of UV light.
More specifically, the present invention relates to a coating composition comprising (A) an activated unsaturated group-containing compound, (B) an activated CH group-containing compound and (C) a basic catalyst, characterized in that the basic catalyst (C) is blocked with an acidic compound whereby the so-blocked catalyst becomes unblocked under the influence of UV light having a wavelength in the range from 250-500 nm.
~ ~ wo 91l~30~, 216 3 8 75 PCT~P94/014~1 ~ 3 , ~t snouid be n3~ed ;ha UV-de~loc!~2Di~ bdSi. ca-ilys~ ar~ n gener I
'<nown ~rom US~301186, US4369206, OF ~-2g403j3 and 0~-A-29403~Z, a "
"n,c,i ~ ;"~. J i !J U I d ~ I y i ~ I ~ O l 1 ' i J U; .i ~J S ' S
2^ ~~rc;~. rhe suitability or sucn blocked ca~lysts for ~s~ in ichc31 addi~ion curin~ caatina systems, howe~en, is no~ ~vicient fr~m ~ny of the a~ove-,~entioned disclosures.
- rhe cod~ing compositions in acc3rdanco ~ith the present invention ~r^
in gener~l suitable ror a varie ~ or C3d-illgs U525, '~or -x2mpl~, ~s ?ainc, impre~nating, sealing ~na oonding composi~ions. The~ are ~a -spec,ally suit-d ror us~ as semi-one ~ac~ ciecori~lYe coa.lngs ind ~s t cl3arc3d~s in nas2coatfclearcoat sys~ems ,~or reriniS,i ^oplic~.ions (e.g., for au~omotive r~~inishes~.
rhese coating composit'ons ,oossess ~x~ended potlire, good curing speed upan oxposure .o UV light (wavelength or 250- 00 nm), ~nd ~ gQod ~dlanC- OF pnysical ind mechanicai ?r~pert~es mak,ng them especiaily well ,uited '~~r the ~rorementioned uses.
Ihese ~nd other r~tur_s ~nd adYd~tdqes ,~ ~he ~resent i;nvention will be more readily unders.ood by those skilled in the ar. ,~rom a eading of he ,~ollowing detailed descrip.ion.
Oe~ail~d Oescriotion of the Pre erred ~moodiments As mentioned earlier, the coating compositions in acc~rdancs with the ares2nt invention ars has2d upan (A) ac~iYat-d unsaturated group-containing compounds, (~) ~cti~atsd C'.~ group-c~n.aining compounds and (C) a basic catalys., ~nich ~dS i C catalys. is oloc~sd in a manner more fully descri~ed below.
iO
-r~ D S~
_ wo ~4/2~075 94/~1451 ~A) Ac~ivated Unsa~urated Group-Conl~ining Compounds As ,uitable compounds containing activated unsaturated groups may generally be mentioned ethylenically unsaturated campounds in which the carbon-car~on double bond is 1c~iYated by a caroonyl group in ~he -sosition. As representative examples or such may be mentioned those compounds disclosed in pre~iously incor~orat-d US275~gl3 (see - especially column 6, line 35 througn column 7, line 45), 0-PS-835809 (ses especially column 3, lines L6-41), US4871822 (see especially column 2, line 14 ~hrougn column d, line 14), U54602061 (see especially column 3, line la through column 4, line !4), US4408018 (see ~specially column 2, lines 1~-68), US42173g6 (s2e especially column 1, line 60 through column 2, line 64) and 'P-A-044~154 (see especially page 2, line 53 througn page 3, line 78).
As a r^irst preterred example may be mentioned the (meth)acrylic esters of compounds containing 1-~ hydroxyl groups and 1-20 carbon atoms.
~nstead of or in addition to (meth)acrylic acid may oe used, 'or example, crotonic acid and cinncmic acid. rhese ^sters may optional~y contain hydroxyl groups. Especially preferred examples include hexane diol diacrylate, trimethylol propane triacrylate and pentaerythritol triacrylat~.
As a second preferred example may be mentioned polyesters oased upon maleic, fumaric andfor itaconic acid (and maleic and itaconic anhydride), and di- or polyvalent hydroxyl compounds, optionally including a monovalent hydroxyl and/or carboxyl compound.
As a third preferred example may be mentioned polyester and/or alkyd restns containing pendant activated unsatùrated groups. These include, for example, urethane (meth)acrylates obtained by reaction of a polyisocyanate with an hydroxyl group-containing (meth)acrylic ~ ester, e.g , ~n nydroxyalkyl es~^r or (metn)acrylic acid or a .omoound prepared by esrerirfication of d polyhydroxyl compound with less than a ~ n~n ~- -t ~ 2 1 ~ 3 8 7 ~ PcT~P9~lot4sl ,i, ~
stoichiometric amount or (meth)acrylic ac,d; polyether (meth)acr~lalas ob~aine~ by est2ri,^~cation or an hydroxyl group-cont~inin~ poTyerher ~ith (meth)acrylic acid; ~olyrunctional (meth)acrylates obtained by reaction of an hydroxyalkyl (me~h)acrylato ~ith a polycarooxylic acid and/or a polyamino resin; poly(meth)acrylales oblained by reac~ion Ol-(meth~acrylic acid ~ith an epoxy resin; and polyalkyimaleates ootainedby reac-ion or a monoalkylmdlea~e estar ~ith an epoxy resin and/ar dn hydroxy runctionaT oligomer or polymer.
'specially prererred of the ac-ivate~ unsaturateci ~roup-coniaining comoounds are the arorementione~ poly~meth)dcrylates obtained by the reaction or (merh)acrylic acid with an epoxy resin.
rt is also especially prererred that the acid value of the activated unsaturated group-containing compoùnds be about 2 or less.
As exemplified by the previously incorporated references, these and other activated unsaturated group-containing compounds, and their methods or production, are aenerally known to those ,killed in the art, and need no rurther explanation here.
(8) Activated C:t Group-Containing Comoounds As suitable compounds containing activated C~ groups may be mentioned a ~ide variety of compounds as ~enerally disclosed in preYiouJly i~c~rpor~ US48J1~22 (see especially column 4, lines 15-28), whicn compounds contain a methylene and/or monosubstituted methylene group in the ~-position to two activating groups such as, ror e,Yample, carbcnyl, cyano, sulfoxide and~or nitro groups. Prererred or these are compounds containing a methylene group in the ~-oosition to t~o carbonyl groups, such as malonate and~or acetoacetate group-containing compounds.
~w o 94~807s 2 1 ~ 3 ~ 7 5 PCTAE~94;01451 .. o .s pr~tarred examples of malonate ~roup-conldinin9 compounds may be menttoned malonic acid eslers dS disclosed in ~reviously incorDc US275~913 (see especially co~umn 8, lines i-~2), and malonate group-containing oligomeric and 30 lymeric compounds as disclosed in pr~viously incorporat3~ US4602061 (see especidlly column !, line ~0 nrousn coiumn Z, line 13). Preferred or these are the oligomeric and/or polymeric malonate group-containing compounds such as, for example, polyurethanes, poiyesters, Qolyacrylat~s, epoxy resins, polyamides and~polyvinyl resins containing malonate groups in the main chain, pendant or both.
0 ,.
~he malonate group-containing polyurethanes may be obtained, '~or example, by reacting a polyisocyanate with an hydroxyl group-containing ester or^ a polyol and malonic acid, or by ~slerific.~tion or ~ransesterification or an hydroxy .,^unctional polyurethane with malonic ~cid or d dialkylmalonate.
Ihe malonare group-containing polyesters may be obta.ined, for example, by the polycondensation of malonic acid, an al~yl malonic acid (such dS ethyl malonic dcid), ~ mono- or dialkyl escer of such a malonic 2Q acid, and/or the reaction product of a malonic ester and an alkyt (meth)acryldte, optionally with other di- or polyc~rboxylic acids;
with di- and/or higher functional hydroxy compounds; ~nd, optionally manofunctional hydroxy and/or carboxyl compounds.
rhe malonate group-containing epoxy esters may be obtained, for example, by esterifying an epoxy resin with malonic acid or a malonic monoester, or by transesterirication with d dialkyl malonate, optionally with other carboxylic acids and derivatives thereof.
rhe malonate group-containing polyamides may be obtained, for example, in the same manner as the polyesters, wherein at least a part of the - hydroxy compound is re~laced with a mono- and/or polyvalent orimary - and/or secondary amine.
~..`,ii ~r ~D :s - -~ o 94/2807~ 216 3 8 7 5 pcTrEp94lol4~l j 7 Other malonate group-cont~ning ~olymers may ~e obtained by the ;ransesterirication of an ~xc~ss of ~ dialkyl malonate with ~n hydroxy-runctional polymer such as, ror example, a ~inyl alcohol/slyrene copolymer. ~n this manner, d polymer with malonat~
group-containing side-chains may be rormed. Any eXcQs, dialkyl mdlonate may be removed under reduced pressur or, optionally, be used as a reactive solvent.
Use may also be made of these malonate group-cantdi-ning compounds in ~hich the malonic acid st.uctural uni- is cyclized, ror ~xamole, by formaldehyde, acetaldehyde, acetone or cyclonexanone.
~.specially prererred of the malonate group-containing compounds for use with the prQsent invenrion ar~ the malonate group-containing oligomeric esters, polyesters, polyurethanes and epaxy ester, L5 containing 2-1aO, more preferably 2-20, malonate groups per molecu~e.
~t is also especially prer~rred that such malonate group-containing comoounds have ~ numoer average molecular weight (~n) in the range of from about 25Q to about 300a, and ~n acid number or aoout 2 or less.
As preferred examples or ac~oacetate group-containing comoounds may oe mentioned acetoacQtic esters ~s disclosed in pr~v~ously incorsorat~d US27~9913 (see aspecia11y column 8, lines ~3-5~), ~iacetoacetate compounds as disclosed in prQviou~ly incorporat~
US42173g6 (see especially column 2, line 6- through column 3, .11ne 27), and acetoacetate group-containing oligomeric and polymeric comoounds as disclosed in pr~viou-ly incorporatcd US4408Ql~ ~se~
especially column 1, line ~1 througn column 2, line 6). Prererr^d o,~
these are the oligomeric and/or polymeric acetoacetal3 ~roup-containing compounds.
~uitable dc~toacetate group-containing oligomeric and polymeric compounds~ c~n be ootained, -,~or exampl~, rrom polyalconols and/or hydroxy-runc.ional polyether, polyester, polyacryldte, vinyl and epcxy ~ ;0 94~2807s 2 ~ 6 3 8 7 ~ PCT~P94/0145I
oliaomers and polymers by reaction ~ith diketene or ~ransesterification ~itn an dlkyl acetoac~rate. ~uch compounds may dlso be obtained by copolymerization or an ac_-o~cetat~ functional acrylic monomer ~ith other vinyl- and/or acrylic-,unctional monomerS.
~specially preterred of the acetoacetate ~roup-containing compounds for use with the present invention are the acetoacetate group-containing oligomers and polymers containing a~t least 2 acetoacetat~ groups. ~t is also especially prererred that such ~c~toacetat~ group-containing compounds should have an Mn in the range IO of from about 234 to about 30000, and in acid numoer of about 2 or less.
Compounds containing both malonate and acetoacetate groups in the same molecule are also suitable and can be obtained, for example, by a icnael reaction between a malonate functional polyester and an acetoac3tate functional acrylic comoound (e.g., acetoacetoxyothyl ~crylate). Additionally, physical mixtures of malonat~ and acetoacetate group-containing compounds are suitable.
Alkylacoroacetates can, in addition, be used as reactiYe diluents.
Optionally, the activated C~ aroups-containing compounds may be utilized in enamine form sucn as ciisclosed ïn EP~ 0420I33, wnicn i.
incorpora~_d by r~farence herein for dll purpo,~, . if u~ly ,.t f~rth.
Agail1 as exemplified by the previously incorporated references, these and other malonate and/or acetoaceta~e group-containing compounds, and their methods of production, lre generally known to those s~illed in the art, and need no further exp1anation here.
As meniioned earlier, the aroredescribed components (A) and ~8) react ~ith ~-~ch ather through a Michael addi~iQn, in ~hich the act~vat-d C;~
grouD of component ~8) adds to one -of the caroon atoms or the ~r.~
~ Yo 94/23a~3 2 1 6 ~ ~ 7 5 P~T~Pg41014~1 ac~ivated unsd~urat3d 9rouD OT camponent (A) Components (A) and (B~
ar~ prereraDly contained in the coatin~ compositions in an amounl such that the ratio ~f the numoer or aclivated C,Y groups to the numoer of activated unsaturated ~roups is in the ran~e of about a,25 to about 4,0, more preferably in the range o,~ aoout 0,~ to aoout 2,0.
(C) ~locked 8asic Cat~lysts As i~dicated earlierT the blocked basic catalysts suitaole for use ~ith the present coating compositions are blocked with an acidic compound, whereoy the so-blocked c~talyst becomes unblocked under the inrluence of UV light having d waYelen5th in the ran~e from 250-SOQ nm ~he bc~sic cq~Alyst f~^y c~p~.~ ~ n ~ ~
As suitable basic catalysts far the Michael addition of !5 components (A) and (8) may be mentioned a ~ide Yariety or well-~nown amine, ammonium and phosphane compounds.dis-lo,c~ n ~h_ pr^Yicusly nc~rporated rcfercnces;
As preferred amine catalysts may be mentioned those of the amtdine type, for exampTe, t3tramethyl guanidine, 1,4-dihydropyrimidines, 1,8-diaza-bicyclo~.4.0~undec-7-ene, 1,4-diaza-bicyclo[2.2.2]octane and 2-alkyl-N-alkyl imidazolines.
As preferred ammonium catalysts may be mentioned quaternary amntonium compounds, for example, quaternary ammonium hydroxides such as tetrabutyl ammonium hydroxide; quaternary ammonium alkoxides such as benzyltrimerhyl ammonium methoxide and dilauryldimethyl ammonium methoxide; and quaternary ammonium carbanions such as benzyltrimethyl ammonium acetyl acetate.
As prer'erred phosphane compounds may be mentioned thos~ disclosed in provi~u311 incorpcrat~d US4871822 (column 7~ line 48 tnhrou~h column 8, line 2), and particularly the tertiary pnosDhanes ~ 94~80~ 21 6 3 8 7 ~ PCT~P94l01151 iisclosed therein. As sDeci'ic preferred ~xamples may be mencioned tri,~hyciroxymethyl)phosphane, ~riphenylphospnane and .ris(p-tolyl)phosphane.
rhese basic catalysts (unolocked) ~re generally utilized in ; amounts ranging rrom abouc Q,05 wt~ to ~'aout 3,0 wt~, preferably rrom about 0,L wt~ to about 1,0 wt~, aased upon the combined weight of components (A) and (8~. -Suitable blocking agents ror these basic caralysts comprise ~cidic compounds select_d rram:
~a) ~-keto carboxylic acids, (b) aromatic or N-heterocyclic substituted fonmic, acetic and oxyacetic acids, and (c) halide compounds.
As rnentioned earlier, suitable ~-~eto carboxylic actd blocking agents are known ,~rom F~eYiou.ly ,ncorparated US43G1186 (column I
line 3~ througn column 2, line 58) and US43~g206 (column 1, line 36 through column 2, line 37). As prererred examples may be mentioned phenyl glyoxylic acid, I-naphtyl glyoxylic acid, pyruvic acid and benzylidiene pyruvic acid.
Suitable aromatic or N-heteracyclic substituted formic, acetic and oxyacetic acid blockin~ agents are known from previou.ly ~ , 3~ 3~-A-294~333 (page 7, line 15 through page 8, line i5). As preferred exampl~s may be mentioned phenyl acetic acid, !-naphtyl acetic acid and 9-anthracene carboxylic acld.
Suitable halide blocktng agents are generally known rrom 0~-A-2940332. Preferred are the anions chloride, bromide and iodtde. rhe halide blockinq agents, howeYer, are-in general less prererr3d because a low molecular. weiqht haloqenide m~y be released upon unblocking or the c~talyst.
L"t;, ,?"~r" ~.
~ WO 94t2807~ 216 3 8 7 ~ PCT/EP94/01451 The acidic compound is preferably utilized in an amount of from about 10 to about 125, more preferably from about 25 to about 125, and especially from about 50 to about 100, equivalent percent required to neutralize the basic catalyst. Within these ratios, the potlife of the composition can be readily varied, for example, between ~ hour at 20C to more than 6 weeks at 50C.
The basic catalyst and blocking agent can be mixed in situ and added to the composition in quantities to result in the desired ratio as set forth above. Alternatively, a salt of the catalyst and blocking agent can be pre-prepared and added to the composition.
The curing of the above-described coating compositions is preferably carried out at ambient temperatures (e.g., 10-30C) under the influence of UV light of a wavelength 250-500 nm, which can be from a UV source or even daylight.
Depending upon the field of application, the coating compositions in accordance with the present invention may optionally contain one or more pigments, dyes and usual intermediary agents, additives and/or solvents. Examples of suitable inert organic solverts include esters, ketones aromatic and aliphatic hydrocarbons. Examples of suitable reactive organic solvents include dimethyl malonate, diethyl malonate, ethyl acetoacetate and 2-ethylhexyl acrylate.
As examples of preferred additives may may be mentioned minor amount:s of a co-binder not containing activated unsaturated or CH
groups, for example, cellulose acetate butyrate, acrylic, epoxy and polyester resins. As is known to one skilled in the art, these co-binders are commonly utilized in the coatings industry to modify certain properties such as drying speed and adhesion to substrates.
12 C A2 163~75 As another preferred additive may be mentioned a UV sensitizer, such as anthracene, which is used to increase the amount of UV light absorbed by the coating 5 composition.
As mentioned earlier, the coating compositions in accordance with the presen invention are suitable for a variety of coatings uses, for example, as paint, impregnating, sealing and bonding compositions. A preferred application is as a semi 10 one-pack decorative coating.
Another preferred application is as a clearcoat in a basecoat/clearcoat system for refinish applications (e.g., automobile refinish). Suitable basecoats for us in such systems are in general well-known in the art. In the method of coating a substrate 15 with a basecoat/clearcoat system, the method comprises applying the basecoat onto the substrate, applying the clearcoat over the basecoat and curing the clearcoat at least in part by expos to UV light. These coating compositions may be applied to a substrate in any convenient manner such as, for example, by brushing, spraying or dipping. Suitable substrates include metals, wood, board, plastics and leather.
The foregoing more general discussion of the present invention will be further illustrated by the following specific examples.
EXAM PLES
(A) Preparation of Activated Unsaturated Group-Containing Compounds (A1 ) Into a reactor were added 1750,0 parts by weight (pbw) of xylene, which were heated.to boiling temperature. Next was added, over a period of three hours, a 30 mixture of 1400,0 pbw of glycidyl methacrylate, 1 935,5 pbw of styrene, 164,5 pbw of butyl acrylate, and -- 2i~387~
186,5 pbw of tert.butyl peroxy-3,5,5-trimethylhexanoate (commercially available under the trade designation Trigonox 42S from Akzo Chemicals), and thereafter an additional 194,0 pbw xylene. The reaction mixture was kept at boiling temperature until a conversion of at least 98% was achieved.
To this first reaction product was added 645,5 pbw of acrylic acid, 6,0 pbw of hydrochinone monomethylether and 1,5 pbw of chromium(III) 2-ethylhexanoate (commercially available under the trade designation Cordova AMC-2 from Cordova Chemicals), and this mixture was reacted at 120C under throughput of air until the acid value had decreased below 1.
After addition of 1361,0 pbw of xylene and 367,0 pbw of n-butanol, a 53,2 wt% polymer solution was obtained with a viscosity of 85,7 cPa.s at 20C, a color of 250 Apha, an acid value of o,1 and an Mn of 3580.
(A2) Into a five liter reaction vessel equipped with a thermometer, stirrer, air sparge and condensor, were charged 1445,6 pbw of isophorone diisocyanate, 160,9 pbw of dry methyl isobutyl ketone, 1,4 pbw of dibutyltin dilaurate and 0,9 pbw of 2,6-di-tert.butyl p-cresol (commercially available under the trade designation Ionol CP from Shell). After heating the mixture under stirring to a temperature of 60C, 1432,6 pbw of 2-hydroxyethylacrylate were added continuously over a period of one hour while a maximum temperature of 65C was maintained by cooling. Subsequently, 0,7 pbw of dibutyltin dialurate dissolved in 6,3 pbw of dry methyl isobutyl ketone were added dropwise over a period of ten minutes, followed by another 420,8 pbw of dry methyl isobutyl ketone.
WO 94/2807~; PCT/EP94/01451 2~6387S
The reaction mixture was thereafter maintained at 65C for four hours, after which the ~CO content of the remaining solution was about 0,5%. 192,4 pbw of n-butanol were then added, and the reaction mixture maintained at 65C until an NCO content of less than 0,1% was achieved (about another two hours).
After cooling to room temperature, an almost colorless solution of a urethane diacrylate was obtained with a non-volatiles content of 79,3% and a viscosity of 900 mPa.s.
(B) Preparation of Activated CH Group-Containing Compounds (B1) In a reactor, 560,0 pbw of Solvesso 100 were heated to a temperature of 160C. Subsequently, over a period of three hours, there was added a mixture of 1336,4 pbw of acetoacetoxyethylmethacrylate, 113,2 pbw of butylacrylate and 550,4 pbw of styrene. Separately from the monomer mixture there was added, over a period of three hours and fifteen minutes, a mixture of 200,0 pbw of Solvesso 100 and 200,0 pbw of Trigonox 42S.
After addition of the peroxide solution, the reaction mixture was cooled to 140C and an additional peroxide solution of 50,0 pbw of Solvesso 100 and 10,0 pbw of Trigonox 42S was added.
Subsequently, after 30 and 60 minutes, further peroxide solutions of 10,0 pbw of Solvesso 100 and 10,0 pbw of Trigonox 42S were added.
After an additional two hours of reaction, the mixture was cooled. Obtained was a polyacetoacetate resin solution with a viscosity of 117 cPas and a solids content of 66,7~. The polyacetoacetate resin possessed an acid number of 2, a theoretical acetoacetate number of 175 and a number average molecular weight (via GPC) of 1270.
~ w o 94/28075 2 1 6 3 8 7 ~ PCT~EP94/014s1 (C)Preparation of Blocked Catalysts (C1) To a solution of 35,5 grams of phenylglyoxylic acid in 150,0 grams tetrahydrofuran were added dropwise 36,0 grams of 1,8-diaza-bicyclo[5.4.0]undec-7-ene. After stirring for thrity minutes, the salt was isolated by evaporation of the solvent.
The recovered salt was purified by means of recrystallization from a solution in 40 ml tetrahydrofuran, yielding a pale yellow salt in a yield of about 67%.
(C2) lhe procedure of (C1) was repeated, except that the phenyl glyoxylic acid was replaced with 52,5 grams of 9-anthracene carboxylic acid.
Example l and Comparative Example 1 A coating composition was prepared from 30,0 grams of (Al), 16,5 grams of (Bl), 3,4 grams of butylacetate and 9,8 grams of a 10%
solution of (C1) in a mixture of butylacetate/methanol (87,5/12,5).
As a comparison, the same coating composition was formulated but instead of the solution of (C1) was utilized 4,9 grams of a 10%
solution of 1,8-diaza-bicyclo~5.4.0]undec-7-ene (DBU) in butylacetate.
These compositions were tested for geltime by storing 100 grams of the reaction mi-xture in a closed tin at a temperature as set forth below. The geltime is reported as the time when the mixture no longer flowed as a liquid upon stirring with a spatula.
Further, both compositions were applied onto a tin plated steel panel with a drawbar to a dry layer thickness of ca. 50~m.
~2~63~75 The panel of Example 1 was irradiated with a 400 Watt mercury lamp at a distance of 38 cm. The panel of Comparative Example 1 was not irradiated.
The petrol resistance of the so-applied coatings was tested qualitatively. After one week cure at 23C a drop of petrol was applied to the test panel. After five minutes, the panel was inspected for coating softening.
The pendulum hardness of the so-applied coatings was also tested after one day and one week cure at 23C with the aid of a Persoz apparatus.
The following results were obtained:
Petrol Persoz Hard. Dry Layer Geltime Resist. 1 day 1 week Thickness Example 1 >1 week at 50C O.K. 35" 137" 51~m Comp. Examp.l 10 min. at 20C O.K. 31" 115" 57~m Example 2 and Comparative Example Z
Example 1 was repeated except that 25 grams of (A2), 33 grams of (B1) and 13,4 grams of the 10% solution of (Cl) were utilized.
Comparative Example 1 was also repeated except that 6,75 grams of the 10% solution of DBU was utilized.
~WO 94/28075 2 1~ 3 ~ 7 ~ PCT/EP94/01451 The following results were obtained:
Petrol Persoz Hard. Dry Layer GeltimeResist. 1 day 1 week Thickness Example 2 ~10 days at 50Cgood 123" 249" 45~m Comp. Examp.2 22 min. at 20Cgood 140" 232" 48~m Example 3 and Comparative Example 3 The composition of Example 1 was repeated except that the solution of (C1) was replaced with 12,1 grams of a 10% solution of (C2) in a mixture of butylacetate/methanol (87,5/12,5).
This composition and the composition of Comparative Example 1 were applied onto a tin plated steel panel with a drawbar to a dry film thickness of ca. 80 ~m. For each composition two panels were prepared. One of each was exposed to daylight, while the other was stored in darkness. The petrol resistance and pendulum hardness were measured as above.
The following results were obtained:
Petrol Persoz Hard. Dry Layer Resist. 1 day 1 week Thickness Example 3 - light O.K. 12" 116" 86~m Example 3 - dark N.O.K. no curing ----Comp. Examp.3 -lightO.K. 21" 130" 78~m Comp. Examp.3 - darkO.K. 20" 128" 82~m
Claims (19)
1. A coating composition comprising (A) an activated unsaturated group-containing compound, (B) an activated CH group-containing compound and (C) a basic catalyst blocked with an acidic compound characterized in that the so-blocked catalyst is capable of being unblocked under the influence of UV light and the blocked basic catalyst is not a quarternary ammonium halide.
2. The coating composition according to claim 1, characterized in that the acidic compound is selected from (a) .alpha.-keto carboxylic acids; (b) aromatic or N-heterocyclic substituted formic, acetic and oxyacetic acids; and (c) halide compounds.
3. The coating composition according to claim 1 or claim 2, characterized in that the basic catalyst (C) comprises a nitrogen base.
4. The coating composition according to claim 3, characterized in that the basic catalyst is selected from amine and ammonium compounds.
5. The coating composition according to claim 1 or claim 2, characterized in that the basic catalyst comprises a phosphane.
6. The coating composition according to any one of claims 1-5, characterized in that the acidic compound is utilized in an amount of from 10 to 125 equivalent percent required to neutralize the basic catalyst.
7. The coating composition according to claim 6, characterized in that the acidic compound is utilized in an amount of from 25 to 125 equivalent percent required to neutralize the basic catalyst.
8. The coating composition according to claim 7, characterized in that the acidic compound is utilized in an amount of from 50 to 100 equivalent percent required to neutralize the basic catalyst.
9. The coating composition according to any one of claims 1-8, characterized in that the basic catalyst (C) and acidic compound together comprise a salt.
10. The coating composition according to any one of claims 1-9, characterized in that (A) and (B) are contained in an amount such that the ratio of the number of activated CH groups to the number of activated unsaturated groups is in the range of 0,25 to 4,0.
11. The coating composition according to any one of claims 1-10, characterized in that the basic catalyst (unblocked) is utilized in an amount ranging from 0,05 wt% to 3,0 wt%, based upon the combined weight of (A) and (B).
12. A coating composition according to any one of claims 1-11, said coating composition being a decorative coating.
13. A method of coating a substrate, said method comprising (1) applying a coating composition comprising (A) an activated unsaturated group-containing compound, (B) an activated CH
group-containing compound and (C) a basic catalyst blocked with an acidic compound wherein the so-blocked catalyst is capable of being unblocked under the influence of UV light, and (2) curing the applied coating at least in part by exposure to UV light.
group-containing compound and (C) a basic catalyst blocked with an acidic compound wherein the so-blocked catalyst is capable of being unblocked under the influence of UV light, and (2) curing the applied coating at least in part by exposure to UV light.
14. A basecoat/clearcoat system, characterized in that the clearcoat is based upon the coating composition according to any one of claims 1-11.
15. A method of coating d substrate with a basecoat/clearcoat system said method comprising (1) applying the basecoat onto the substrate, (2) applying the clearcoat over the basecoat, said clearcoat comprising (A) an activated unsaturated group-containing compound, (B) an activated CH group-containing compound and (C) a basic catalyst blocked with an acidic compound wherein the so-blocked catalyst is capable of being unblocked under the influence of UV light, and (3) curing the clearcoat at least in part by exposure to UV light.
16. The method according to any one of claims 13 and 15 wherein the acidic compound is selected from (a) .alpha.-keto carboxylic acids; (b) aromatic or N-heterocyclic substituted formic, acetic and oxyacetic acids; and (c) halide compounds.
17. The method according to any one of the claims 13, 15 and 16 wherein the basic catalyst (C) comprises a nitrogen base.
18. The method according to claim 17 wherein the basic catalyst is selected from amine and ammonium compounds.
19. The method according to any one of the claims 13 and 15-16 wherein the basic catalyst comprises a phosphane.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP93201513 | 1993-05-26 | ||
| EP93201513.4 | 1993-05-26 | ||
| PCT/EP1994/001451 WO1994028075A1 (en) | 1993-05-26 | 1994-05-03 | Coating composition including a uv-deblockable basic catalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2163875A1 true CA2163875A1 (en) | 1994-12-08 |
Family
ID=8213849
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002163875A Abandoned CA2163875A1 (en) | 1993-05-26 | 1994-05-03 | Coating composition including a uv-deblockable basic catalyst |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0702707A1 (en) |
| CN (1) | CN1126484A (en) |
| CA (1) | CA2163875A1 (en) |
| FI (1) | FI955613A (en) |
| NO (1) | NO954787L (en) |
| WO (1) | WO1994028075A1 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19520888A1 (en) * | 1995-06-08 | 1996-12-12 | Basf Ag | Radiation-curable compositions containing multifunctional acrylates and blocked amines |
| DE19535161A1 (en) * | 1995-09-22 | 1997-03-27 | Basf Ag | Radiation-curable compositions containing surface-active, blocked amino compounds |
| BR9707687A (en) † | 1996-02-22 | 1999-07-27 | Dsm Nv | Anionic photocatalyst |
| JP3984488B2 (en) * | 2001-03-27 | 2007-10-03 | 日本ペイント株式会社 | Curable coating composition and coating film forming method |
| EP1436297B1 (en) | 2001-10-17 | 2007-04-25 | Ciba Specialty Chemicals Holding Inc. | Photoactivable nitrogen bases |
| CN101044179B (en) | 2004-09-17 | 2011-07-06 | 阿克佐诺贝尔国际涂料股份有限公司 | Coating composition based on thiol-NCO curing |
| CN101641643B (en) | 2007-04-03 | 2013-08-07 | 巴斯夫欧洲公司 | Photoactivable nitrogen bases |
| EP2192447A1 (en) | 2008-11-27 | 2010-06-02 | Akzo Nobel Coatings International B.V. | Method of applying a pattern to a substrate |
| WO2013119845A1 (en) | 2012-02-07 | 2013-08-15 | Vibrant Holdings, Llc | Substrates, peptide arrays, and methods |
| US10006909B2 (en) | 2012-09-28 | 2018-06-26 | Vibrant Holdings, Llc | Methods, systems, and arrays for biomolecular analysis |
| US10286376B2 (en) | 2012-11-14 | 2019-05-14 | Vibrant Holdings, Llc | Substrates, systems, and methods for array synthesis and biomolecular analysis |
| CA3183995A1 (en) * | 2012-11-14 | 2014-05-22 | Vibrant Holdings, Llc | Substrates, systems, and methods for array synthesis and biomolecular analysis |
| CA2901029C (en) | 2013-02-15 | 2020-06-16 | John J. Rajasekaran | Methods and compositions for amplified electrochemiluminescence detection |
| CA2940177C (en) | 2014-02-21 | 2020-02-25 | Vasanth JAYARAMAN | Selective photo activation of amino acids for single step peptide coupling |
| EP3288517B1 (en) | 2015-04-29 | 2019-07-17 | BSN Medical GmbH | Medical bathing device |
| BR112017023057B1 (en) | 2015-04-29 | 2023-03-28 | Bsn Medical Gmbh | PROCESS FOR PREPARING NO AND COSMETIC PROCESS |
| US10538808B2 (en) | 2017-05-26 | 2020-01-21 | Vibrant Holdings, Llc | Photoactive compounds and methods for biomolecule detection and sequencing |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2830953A1 (en) * | 1978-07-14 | 1980-01-24 | Bayer Ag | AMMONIUM SALTS OF ALPHA KETOCARBONIC ACIDS |
| DE2940333A1 (en) * | 1979-10-04 | 1981-05-07 | Bayer Ag, 5090 Leverkusen | AMMONIUM SALTS, A METHOD FOR PRODUCING THE AMINES ON WHICH THEY ARE BASED, AND THE COATING MEASURES CONTAINING THE AMMONIUM SALTS ON THE BASIS OF POLYURETHANE OR EPOXY RESIN PRE-PRODUCTS |
| EP0160824B2 (en) * | 1984-04-04 | 1994-08-03 | Hoechst Aktiengesellschaft | Reaction product of olefinically unsaturated compounds with active hydrogen compounds, process for their preparation and 2-component coating systems based thereon |
| EP0448154A1 (en) * | 1990-03-20 | 1991-09-25 | Akzo Nobel N.V. | Coating composition including a blocked basic catalyst |
-
1994
- 1994-05-03 CA CA002163875A patent/CA2163875A1/en not_active Abandoned
- 1994-05-03 EP EP94916207A patent/EP0702707A1/en not_active Withdrawn
- 1994-05-03 CN CN 94192602 patent/CN1126484A/en active Pending
- 1994-05-03 WO PCT/EP1994/001451 patent/WO1994028075A1/en not_active Application Discontinuation
-
1995
- 1995-11-22 FI FI955613A patent/FI955613A/en not_active Application Discontinuation
- 1995-11-24 NO NO954787A patent/NO954787L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| FI955613A (en) | 1995-12-19 |
| CN1126484A (en) | 1996-07-10 |
| NO954787D0 (en) | 1995-11-24 |
| NO954787L (en) | 1996-01-23 |
| FI955613A0 (en) | 1995-11-22 |
| EP0702707A1 (en) | 1996-03-27 |
| WO1994028075A1 (en) | 1994-12-08 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |