CA1196444A - Light stabilization of acid-catalysed stoving lacquers of unsaturated poly-acrylics or polyesters - Google Patents
Light stabilization of acid-catalysed stoving lacquers of unsaturated poly-acrylics or polyestersInfo
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- CA1196444A CA1196444A CA000389590A CA389590A CA1196444A CA 1196444 A CA1196444 A CA 1196444A CA 000389590 A CA000389590 A CA 000389590A CA 389590 A CA389590 A CA 389590A CA 1196444 A CA1196444 A CA 1196444A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/34—Heterocyclic compounds having nitrogen in the ring
- C08K5/3442—Heterocyclic compounds having nitrogen in the ring having two nitrogen atoms in the ring
- C08K5/3445—Five-membered rings
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/34—Heterocyclic compounds having nitrogen in the ring
- C08K5/3412—Heterocyclic compounds having nitrogen in the ring having one nitrogen atom in the ring
- C08K5/3432—Six-membered rings
- C08K5/3435—Piperidines
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/34—Heterocyclic compounds having nitrogen in the ring
- C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
- C08K5/3477—Six-membered rings
- C08K5/3492—Triazines
- C08K5/34926—Triazines also containing heterocyclic groups other than triazine groups
-
- 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
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/48—Stabilisers against degradation by oxygen, light or heat
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Paints Or Removers (AREA)
- Hydrogenated Pyridines (AREA)
Abstract
ABSTRACT
Light stabilisers which contain the group of the formula IV
Light stabilisers which contain the group of the formula IV
Description
4~
Case 3-13140/S/l+2/~
Li~ht st~bilisation of acid-cat21ysed_stoving lacauers The present invention relates to the stabilisation of acid-catalysed stoving lacquers based on hot-crosslinkable acrylic, polyester or alkyd resins against the action of light and moisture, by the addition of ~-substituted polyalkylpiperidine derivatives, and also to the acid-catalysed stoving lacquers so stabilised.
From case to case, but especially for retouching finishes and lacquers with a high solids content for the industrial finish sector, stoving lacquer systems based on hot-crosslinkable acrylic, polyester or alkyd resins are provided with an additional acid catalyst. If light stabilisers of the type con~.prising the polyalkylpiperidine derivatives are also used in such systems, precipitation resulting from the formation of a sal~ caused by the light stabiliser and the acid catalyst, delays in curing, pigment flocculations and a reduced light stabilising effect, are frequently observed.
In European patent application 6,213 the proposal has been made to solve these problems by using only those polyalkylpiperidine light stabilisers in which the piperidine nitrogen is substituted, especially those light stabilisers which contain a group of the formula I
~ / 3 1 ~ / \ (I) RCh2 C}l3 in ~:hich R is hydrogen or metllyl ~nd Rl is Cl-Cl8 alkyl, Cl-C6 hydro~y-al~yl~ C3-Cs all;ellyl, C3-C8 alliynyl, C7-C12 aralkyl ~hicll can be ~ published January 9, 1980; see also Canadian Patent 1,149,534.
substituted by hydroxyl in the alkyl moiety, Cl-C8 alkanoyl or C3-C5 alkenoyl.
In acid-catalysed lacquers, N-substituted piperidine derivatives of this type do indeed have considerably more advantageous properties with regard to the failure symptoms observed than their N-unsubstituted analogs, i.e. the compounds of the formula I in which Rl is hydrogen.
It has been found that many of the N-substituted light stabilisers described in European patent application 6,213 in certain cases do not meet the requirements of practice in the field of coating materials technoiogy. Using very low catalyst concentrations, and also at low stoving temperatures, considerable delays in curing can occur. The cured lacquers can become opaque when stored in a moist atmosphere -a phenomenon termed "blushing" by those skilled in the art. In addition, the cured lacquers can possess inadequate stability to solvents and inadequaLe scratch resistance. ~owever, it has been found that specific selected compounds of the formula I do not have these disadvantages and hence are suitable preferred light stabilisers for acid-catalysed stoving lacquers. Such compounds are those of the formula I in which Rl is an acyl group, for example, an alkanoyl, alkenoyl, aralkenoyl, alkoxycarbonyl or carbamoyl group.
Accordingly, the invention relates to the use of compounds of formula IV
__ _ R-CH2~L_,R
Rl _ ~ N = C = 8 (IV) R-CH2 CH3 _ n ;
;n which:
n represents 1 or 2;
R represents hydrogen or methyl.;
Rl represents Cl-G8 alkanoyl~ C3-C5 alkanoyl, sorboyl, cinnamoyl~ C2-C5 alkoxycarbonyl or a group (R2)(R3)NC0-, in which R2 is Cl-C2 alkyl, cyclohexyl, phenyl, or phenyl substituted by halogen, Cl-C4 alkyl or Cl-C~ alkoxy and R3 is hydrogen, Cl-C12 alkyl, cyclohexyl or benzyl;
R7 represents hydrogen, Cl-C12 alkyl, allyl~ benzyl or C2-C6 alkoxyalkyl;
and R8, if n is 1, represents hydrogen, Cl-C12 alkyl, glycidyl, C3-C5 alkenyl, C7-Cg aralkyl, C5-C7 cycloalkyl, C2-C6 acyloxyalkyl or C6-C10 aryl, or R8, if n is 2, represents C2-C12 alkylene, C6~C12 arylene, or a -cH2cH(oRl)cH2~ ocH2-cH(oRl)cH2 ~ group.
Examples of Rl in the above formul3 ~are alkanoyl groups, such as the formyl, acetyl, propionyl, butyryl, valerianyl, capronyl or capryloyl group;
alkenoyl groups, such as the acryloyl, methacryloyl or crotonoyl group; the sorboyl group (CH3CH=CHCH=CHC0-); the cinnamoyl group (phenyl-CH=CH-C0-); an alkoxycarbonyl group, such as the methoxycarbonyl, ethoxycarbonyl or butoxycarbonyl group; a N-monosubstituted carbamoyl group, such as the methylaminocarbonyl, butylaminocarbonyl, octylaminocarbonyl, dodecylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, tolylaminocarbonyl or chlorophenylaminocarbonyl group; or a N-disubstituted carbamoyl group, for example the dimethylaminocarbonyl, diisopropylaminocarbonyl, diethylaminocarbonyl, dibutylaminocarbonyl, dihexylaminocarbonyl9 dioctylaminocarbonyl, methyl-octylaminocarbonyl, methylcyclohexylaminocarbonyl, dicyclohexylaminocarbonyl, methylbenzylaminocarbonyl, ethylphenylaminocarbonyl or methylchlorophenylamino-carbonyl group. Preferably, Rl is a C2-C~ alkanoyl group or C3-C5 alkenoyl group and in particular an acetyl, acryloyl or methacryloyl group.
R is preferably hydrogen. In th;s case, the compounds of the formula I are derivatives of 2,2,6,6-tetramethy]piperidine.
Examples of polyalkylpiperidine light stabilisers of this class are:
3-dodecyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5]decane-2,4-dione, 3-benzyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5]decane-2,4-dione, 3-n-octyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acryloyl-spiro[4.5]decane-2,4-dione, 3-allyl-1,3,8-triaza-1,7,7,9,9-pentamethyl-8-propionyl-spiro[4.5]decane-
Case 3-13140/S/l+2/~
Li~ht st~bilisation of acid-cat21ysed_stoving lacauers The present invention relates to the stabilisation of acid-catalysed stoving lacquers based on hot-crosslinkable acrylic, polyester or alkyd resins against the action of light and moisture, by the addition of ~-substituted polyalkylpiperidine derivatives, and also to the acid-catalysed stoving lacquers so stabilised.
From case to case, but especially for retouching finishes and lacquers with a high solids content for the industrial finish sector, stoving lacquer systems based on hot-crosslinkable acrylic, polyester or alkyd resins are provided with an additional acid catalyst. If light stabilisers of the type con~.prising the polyalkylpiperidine derivatives are also used in such systems, precipitation resulting from the formation of a sal~ caused by the light stabiliser and the acid catalyst, delays in curing, pigment flocculations and a reduced light stabilising effect, are frequently observed.
In European patent application 6,213 the proposal has been made to solve these problems by using only those polyalkylpiperidine light stabilisers in which the piperidine nitrogen is substituted, especially those light stabilisers which contain a group of the formula I
~ / 3 1 ~ / \ (I) RCh2 C}l3 in ~:hich R is hydrogen or metllyl ~nd Rl is Cl-Cl8 alkyl, Cl-C6 hydro~y-al~yl~ C3-Cs all;ellyl, C3-C8 alliynyl, C7-C12 aralkyl ~hicll can be ~ published January 9, 1980; see also Canadian Patent 1,149,534.
substituted by hydroxyl in the alkyl moiety, Cl-C8 alkanoyl or C3-C5 alkenoyl.
In acid-catalysed lacquers, N-substituted piperidine derivatives of this type do indeed have considerably more advantageous properties with regard to the failure symptoms observed than their N-unsubstituted analogs, i.e. the compounds of the formula I in which Rl is hydrogen.
It has been found that many of the N-substituted light stabilisers described in European patent application 6,213 in certain cases do not meet the requirements of practice in the field of coating materials technoiogy. Using very low catalyst concentrations, and also at low stoving temperatures, considerable delays in curing can occur. The cured lacquers can become opaque when stored in a moist atmosphere -a phenomenon termed "blushing" by those skilled in the art. In addition, the cured lacquers can possess inadequate stability to solvents and inadequaLe scratch resistance. ~owever, it has been found that specific selected compounds of the formula I do not have these disadvantages and hence are suitable preferred light stabilisers for acid-catalysed stoving lacquers. Such compounds are those of the formula I in which Rl is an acyl group, for example, an alkanoyl, alkenoyl, aralkenoyl, alkoxycarbonyl or carbamoyl group.
Accordingly, the invention relates to the use of compounds of formula IV
__ _ R-CH2~L_,R
Rl _ ~ N = C = 8 (IV) R-CH2 CH3 _ n ;
;n which:
n represents 1 or 2;
R represents hydrogen or methyl.;
Rl represents Cl-G8 alkanoyl~ C3-C5 alkanoyl, sorboyl, cinnamoyl~ C2-C5 alkoxycarbonyl or a group (R2)(R3)NC0-, in which R2 is Cl-C2 alkyl, cyclohexyl, phenyl, or phenyl substituted by halogen, Cl-C4 alkyl or Cl-C~ alkoxy and R3 is hydrogen, Cl-C12 alkyl, cyclohexyl or benzyl;
R7 represents hydrogen, Cl-C12 alkyl, allyl~ benzyl or C2-C6 alkoxyalkyl;
and R8, if n is 1, represents hydrogen, Cl-C12 alkyl, glycidyl, C3-C5 alkenyl, C7-Cg aralkyl, C5-C7 cycloalkyl, C2-C6 acyloxyalkyl or C6-C10 aryl, or R8, if n is 2, represents C2-C12 alkylene, C6~C12 arylene, or a -cH2cH(oRl)cH2~ ocH2-cH(oRl)cH2 ~ group.
Examples of Rl in the above formul3 ~are alkanoyl groups, such as the formyl, acetyl, propionyl, butyryl, valerianyl, capronyl or capryloyl group;
alkenoyl groups, such as the acryloyl, methacryloyl or crotonoyl group; the sorboyl group (CH3CH=CHCH=CHC0-); the cinnamoyl group (phenyl-CH=CH-C0-); an alkoxycarbonyl group, such as the methoxycarbonyl, ethoxycarbonyl or butoxycarbonyl group; a N-monosubstituted carbamoyl group, such as the methylaminocarbonyl, butylaminocarbonyl, octylaminocarbonyl, dodecylaminocarbonyl, cyclohexylaminocarbonyl, phenylaminocarbonyl, tolylaminocarbonyl or chlorophenylaminocarbonyl group; or a N-disubstituted carbamoyl group, for example the dimethylaminocarbonyl, diisopropylaminocarbonyl, diethylaminocarbonyl, dibutylaminocarbonyl, dihexylaminocarbonyl9 dioctylaminocarbonyl, methyl-octylaminocarbonyl, methylcyclohexylaminocarbonyl, dicyclohexylaminocarbonyl, methylbenzylaminocarbonyl, ethylphenylaminocarbonyl or methylchlorophenylamino-carbonyl group. Preferably, Rl is a C2-C~ alkanoyl group or C3-C5 alkenoyl group and in particular an acetyl, acryloyl or methacryloyl group.
R is preferably hydrogen. In th;s case, the compounds of the formula I are derivatives of 2,2,6,6-tetramethy]piperidine.
Examples of polyalkylpiperidine light stabilisers of this class are:
3-dodecyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5]decane-2,4-dione, 3-benzyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5]decane-2,4-dione, 3-n-octyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acryloyl-spiro[4.5]decane-2,4-dione, 3-allyl-1,3,8-triaza-1,7,7,9,9-pentamethyl-8-propionyl-spiro[4.5]decane-
2,4-dione or the compounds of the following formulae:
~ / 3~ NH-C=O O-C-N ~ ~\ /CH3 C-d CO-N/ I I / /N-COCH3 - C -~-CH2cHc~2~[cH2 CI~C~2]2 l~ C~ \CH3 o oocca3 oocc~ o 1 3 \ / 3. f~H-C=O O=C-N ~ \./ 3 1 3 C~2=C-CO~ \ ~N~COC=C~2 ~ C -N~(CH ) -N - C
~ / 3~ NH-C=O O-C-N ~ ~\ /CH3 C-d CO-N/ I I / /N-COCH3 - C -~-CH2cHc~2~[cH2 CI~C~2]2 l~ C~ \CH3 o oocca3 oocc~ o 1 3 \ / 3. f~H-C=O O=C-N ~ \./ 3 1 3 C~2=C-CO~ \ ~N~COC=C~2 ~ C -N~(CH ) -N - C
3 3 O 2 t~ 3 3 3\ / 3 \ ~ ~ C=O CH3 ca CH3co-N\ / \ ~ / \ /N~CocH3 ~ C ~N~ CH~ N-C ,-~
3 3 ~ = D/ o CX~ ~CH
It is also possible to use polyalkylpiperidine light stabilisers which form chemical bonds with the binder of the lacquer. This occurs when the polyalkylpiperidine derivative possesses a reactive group suitable for this purpose, Eor example a glycidyl, hydroxyl or methylol group.
If the piperidine light stabiliser contains a polymerisable group, for example an acroyl or methacroyl group as Rl, or in another position in the molecule, the light stabiliser can copolymerise with the binder of the lacquer if the binder also has polymerisable groups. This occurs, for example, with acrylic resins or acryl-modified alkyd resins.
The advantage in these cases is that the light stabilisers cannot be removed by extraction or migration, so that their effect is very long-lasting.
-The acrylic resin lacquers which can be stabilised in the practice of this invention against light are the conventional acrylic resin stoving lacquers,which are described, for e~ample, in H. Kittel's Lehrbuch der Lacke und Beschichtungen (Textbook of Lacquers and Coatings)9 Volume 1, Part 2, on pages 735 and 742 (Berlin, 1972) and in H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) (1971), on pages 229-238.
The polyester lacquers which can be stabilised in the practice of this invention against the action of light are the conventional stoving lacquers which are described, for example, in H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) (1971), on pages 86-99.
The alkyd resin lacquers which can be stabilised in the practice of this invention against the action of light are the conventional stoving lacquers which are used, in particular, for the lacquer-coating of automobiles (so-called automotive finishing lacquers), for example lacquers based on alkyd-melamine resins and alkyd-acrylic-melamine resins (see H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) ~1971), pages 99-127).
The stoving lacquers stabilised in the practice of this invention can also contain mixtures of acrylic, polyester and alkyd resins with one another or with other coating resins. The acrylic, polyester and
3 3 ~ = D/ o CX~ ~CH
It is also possible to use polyalkylpiperidine light stabilisers which form chemical bonds with the binder of the lacquer. This occurs when the polyalkylpiperidine derivative possesses a reactive group suitable for this purpose, Eor example a glycidyl, hydroxyl or methylol group.
If the piperidine light stabiliser contains a polymerisable group, for example an acroyl or methacroyl group as Rl, or in another position in the molecule, the light stabiliser can copolymerise with the binder of the lacquer if the binder also has polymerisable groups. This occurs, for example, with acrylic resins or acryl-modified alkyd resins.
The advantage in these cases is that the light stabilisers cannot be removed by extraction or migration, so that their effect is very long-lasting.
-The acrylic resin lacquers which can be stabilised in the practice of this invention against light are the conventional acrylic resin stoving lacquers,which are described, for e~ample, in H. Kittel's Lehrbuch der Lacke und Beschichtungen (Textbook of Lacquers and Coatings)9 Volume 1, Part 2, on pages 735 and 742 (Berlin, 1972) and in H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) (1971), on pages 229-238.
The polyester lacquers which can be stabilised in the practice of this invention against the action of light are the conventional stoving lacquers which are described, for example, in H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) (1971), on pages 86-99.
The alkyd resin lacquers which can be stabilised in the practice of this invention against the action of light are the conventional stoving lacquers which are used, in particular, for the lacquer-coating of automobiles (so-called automotive finishing lacquers), for example lacquers based on alkyd-melamine resins and alkyd-acrylic-melamine resins (see H. Wagner and H.F. Sarx, Lackkunstharze (Synthetic Resins for Lacquers) ~1971), pages 99-127).
The stoving lacquers stabilised in the practice of this invention can also contain mixtures of acrylic, polyester and alkyd resins with one another or with other coating resins. The acrylic, polyester and
4~
alkyd resins can be self-crosslinking when hot, or they are used in a mixture with crosslinking agents, for which, in particular, melamine resins are suitable.
The acid-catalysed stoving lacquers stabilised according to the invention are suitable both for metallic pigmented finishes and for solid-shade finishes, especially for retouching. The lacquers stabilised according to the invention are preferably applied in the conventional manner by one o~ two methods, either by the single-coat method or by the two-coat method. In the latter method, the pigment-containing coat is-first applied and a top coat of clear lacquer is then applied ~er this. When~used in two-coat finishesj the:-polyalkylpiperidine derivative can be incorporated either only into the non-pigmente~ top-coat lacquer or into both the non-pigmente~ top-coat lacquer and the pigment-containing priming lacquer.
The amount of polyalkylpiperidine derivative added is 0.01 to 5% by weight, based on the solvent-free binder, and preferably 0.5 to 1~ by weight. The lacquers can be dissolved or dispersed in conventional organic solvents or in water, or they can be solvent-free.
The coating resins of the invention are suitable, in particular, for the "high solids" industrial lacquers which are becoming increasingly important in particular in the automotive industry and in the repair of automobiles, especially for applications at a low curing temperature.
To achieve maximum stability to light, it can be advantageous to use other conventional light stabilisers concurrently, for example UV
absorbers or organic nickel compounds. The concurrent use of UV
absorbers of the type comprising the 2-hydroxybenzophenones, 2-(2-hydroxyphenyl)-benztriazoles or the oxa]anilides, which can exert a synergistic effect, is of particular importance. Examples of such UV absorbers are 2-(2-hydroxy-3,5-di-t-amyl-phenyl)-benz-triazole, 2-[2-hydroxy-3,5-di(~-dimethylbenzyl)-phenyl]-benztriazole, 2-(2-hydroxy-5-t--octyl-phenyl)-benztriazole~ 2-(2-hydroxy-3,5-di-t-octyl-phenyl)-benztriazole, 2,4-di~ydroxybenzophenone, 2-hydroxy-4-octyloxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2-ethyl-2'-ethoxy-4'-t-butyl-oxalanilide or 2-ethyl-2'-ethoxy-oxalanilide.
When using such combinations, the sum of all light stabilisers is 0.2 to 5% by weight and preferably 0.5 to 2% by weight, based on the coating resin.
Further additives which can be contained in the lacquer are anti-oxidants, for example those of the type comprising sterically hindered phenol derivatives7 phosphorus compounds, such as phosphites, phosphines or phosphonites, plasticisers, levelling assistants9 curing accelerators, thickeners, dispersants or adhesion promoters.
The following example describesthe use of N-acylated polyalkylpiperi-dine derivatives in acid-catalysed stoving lacquers. Parts and percentages are by weight.
Example 1: Stabilising a two-coat metallic pigmented lacquer against weathering Basic recipe for the lacquers a) Metallic pigmented lacquer 27 parts of polyester resin (L 1850* Dynamit Novel AG), 3 parts of melamine resin (Maprenal RTY;, Farbwerke Hoechst AG), 2 parts of cellulose acetobutyrate (CAB 531, Eastman Chem. Corp.), 8 parts of aluminium bronze (ALCOA 726-:;, Aluminium Corp. of America), 10 parts of toluene, 7 parts of xylene, 3 parts of butanol, 25 parts of butyl acetate and 15 parts of an aromatic solvent mixture (Solvesso 150;, ESSO AG).
~;Trade Mark ~~
b) Non-pigmented Einishing lacquer ,,~
56 parts of acrylic resin (Paraloid OL 42, Rohm and ~aas Corp.), 20 parts of melamine resin ~Cymel ~01, American Cyanamid Corp.), 0.3 part of p-toluenesulfonic acid, 2 parts of cellulose acetobutyrate (CAB 551, ~astman Chem. Corp.), 3 parts of levelling assistant, 11 parts of butanol and 8 parts of butyl acetate.
Aluminium sheets measuring 57 x 79 x 0.55 mm, which were coated with a priming lacquer based on polyester/epoxide resin, were coated first with the metallic pigmented lacquer and then with the finishing lacquer.
The first-coat lacquer was applied by spraying to give a coating thickness of about 15~ and was exposed to air for about 10 minutes. The clear lacquer was then applied by spraying to give a coating thickness of about 30 ~.
After exposure to air Eor 15 minutes, the samples are stoved at 120C and then subjected to weathering in a UVC0~1 weathering device (available from the Atlas Corp.) in a cycle of 4 hours UV
irradiation at 60C and 4 hours water vapour condensation at 50C.
The surface gloss of the samples is measured at intervals of 200 hours by the method of ~STM D 523.
3-Dodecyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5~decan-2,4-dione (=LS V) ~ /CH3 LS V C~ C0~
~ CH3 I r was used as light stabiliser of the invention in an amount of 1%, based on the solids content of the finishing lacquer, alone and in combination with a UV absorber of the benztriazole type. The results are reported in Table 3.
Table 3 Light stabiliser Surface gloss 20 after 0 200 400600 800 h weathering without 77 52 16 4 1% LS V 80 60 55 24 10 1% LS V + *) 1% Tinuvin 900 82 73 74 61 40 - )2-[2-hydroxy-3,5-di(~-dimethylbenzyl)-phenyl]-benztriazole *
Trade Mark _ g _ . .
alkyd resins can be self-crosslinking when hot, or they are used in a mixture with crosslinking agents, for which, in particular, melamine resins are suitable.
The acid-catalysed stoving lacquers stabilised according to the invention are suitable both for metallic pigmented finishes and for solid-shade finishes, especially for retouching. The lacquers stabilised according to the invention are preferably applied in the conventional manner by one o~ two methods, either by the single-coat method or by the two-coat method. In the latter method, the pigment-containing coat is-first applied and a top coat of clear lacquer is then applied ~er this. When~used in two-coat finishesj the:-polyalkylpiperidine derivative can be incorporated either only into the non-pigmente~ top-coat lacquer or into both the non-pigmente~ top-coat lacquer and the pigment-containing priming lacquer.
The amount of polyalkylpiperidine derivative added is 0.01 to 5% by weight, based on the solvent-free binder, and preferably 0.5 to 1~ by weight. The lacquers can be dissolved or dispersed in conventional organic solvents or in water, or they can be solvent-free.
The coating resins of the invention are suitable, in particular, for the "high solids" industrial lacquers which are becoming increasingly important in particular in the automotive industry and in the repair of automobiles, especially for applications at a low curing temperature.
To achieve maximum stability to light, it can be advantageous to use other conventional light stabilisers concurrently, for example UV
absorbers or organic nickel compounds. The concurrent use of UV
absorbers of the type comprising the 2-hydroxybenzophenones, 2-(2-hydroxyphenyl)-benztriazoles or the oxa]anilides, which can exert a synergistic effect, is of particular importance. Examples of such UV absorbers are 2-(2-hydroxy-3,5-di-t-amyl-phenyl)-benz-triazole, 2-[2-hydroxy-3,5-di(~-dimethylbenzyl)-phenyl]-benztriazole, 2-(2-hydroxy-5-t--octyl-phenyl)-benztriazole~ 2-(2-hydroxy-3,5-di-t-octyl-phenyl)-benztriazole, 2,4-di~ydroxybenzophenone, 2-hydroxy-4-octyloxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2-ethyl-2'-ethoxy-4'-t-butyl-oxalanilide or 2-ethyl-2'-ethoxy-oxalanilide.
When using such combinations, the sum of all light stabilisers is 0.2 to 5% by weight and preferably 0.5 to 2% by weight, based on the coating resin.
Further additives which can be contained in the lacquer are anti-oxidants, for example those of the type comprising sterically hindered phenol derivatives7 phosphorus compounds, such as phosphites, phosphines or phosphonites, plasticisers, levelling assistants9 curing accelerators, thickeners, dispersants or adhesion promoters.
The following example describesthe use of N-acylated polyalkylpiperi-dine derivatives in acid-catalysed stoving lacquers. Parts and percentages are by weight.
Example 1: Stabilising a two-coat metallic pigmented lacquer against weathering Basic recipe for the lacquers a) Metallic pigmented lacquer 27 parts of polyester resin (L 1850* Dynamit Novel AG), 3 parts of melamine resin (Maprenal RTY;, Farbwerke Hoechst AG), 2 parts of cellulose acetobutyrate (CAB 531, Eastman Chem. Corp.), 8 parts of aluminium bronze (ALCOA 726-:;, Aluminium Corp. of America), 10 parts of toluene, 7 parts of xylene, 3 parts of butanol, 25 parts of butyl acetate and 15 parts of an aromatic solvent mixture (Solvesso 150;, ESSO AG).
~;Trade Mark ~~
b) Non-pigmented Einishing lacquer ,,~
56 parts of acrylic resin (Paraloid OL 42, Rohm and ~aas Corp.), 20 parts of melamine resin ~Cymel ~01, American Cyanamid Corp.), 0.3 part of p-toluenesulfonic acid, 2 parts of cellulose acetobutyrate (CAB 551, ~astman Chem. Corp.), 3 parts of levelling assistant, 11 parts of butanol and 8 parts of butyl acetate.
Aluminium sheets measuring 57 x 79 x 0.55 mm, which were coated with a priming lacquer based on polyester/epoxide resin, were coated first with the metallic pigmented lacquer and then with the finishing lacquer.
The first-coat lacquer was applied by spraying to give a coating thickness of about 15~ and was exposed to air for about 10 minutes. The clear lacquer was then applied by spraying to give a coating thickness of about 30 ~.
After exposure to air Eor 15 minutes, the samples are stoved at 120C and then subjected to weathering in a UVC0~1 weathering device (available from the Atlas Corp.) in a cycle of 4 hours UV
irradiation at 60C and 4 hours water vapour condensation at 50C.
The surface gloss of the samples is measured at intervals of 200 hours by the method of ~STM D 523.
3-Dodecyl-1,3,8-triaza-7,7,9,9-tetramethyl-8-acetyl-spiro[4.5~decan-2,4-dione (=LS V) ~ /CH3 LS V C~ C0~
~ CH3 I r was used as light stabiliser of the invention in an amount of 1%, based on the solids content of the finishing lacquer, alone and in combination with a UV absorber of the benztriazole type. The results are reported in Table 3.
Table 3 Light stabiliser Surface gloss 20 after 0 200 400600 800 h weathering without 77 52 16 4 1% LS V 80 60 55 24 10 1% LS V + *) 1% Tinuvin 900 82 73 74 61 40 - )2-[2-hydroxy-3,5-di(~-dimethylbenzyl)-phenyl]-benztriazole *
Trade Mark _ g _ . .
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of stabilizing acid-catalysed stoving lacquers based on hot-crosslinkable acrylic, polyester or alkyd resins against the action of light, by addition of a stabilizing amount of a compound of the formula (IV):
(IV) in which:
n represents 1 or 2;
R represents hydrogen or methyl;
R1 represents C1-C8 alkanoyl, C3-C5 alkenoyl, sorboyl, cinnamoyl, C2-C5 alkoxycarbonyl, or a group (R2)(R3)NCO-, in which R2 is C1-C12 alkyl, cyclohexyl, phenyl, or phenyl substituted by halogen, C1-C4 alkyl, or C1-C4 alkoxy and R3 is hydrogen, C1-C12 alkyl, cyclohexyl, or benzyl;
R7 represents hydrogen, C1-C12 alkyl, allyl, benzyl or C2-C6 alkoxyalkyl; and R8, if n is 1, represents hydrogen, C1-C12 alkyl, glycidyl, C3-C5 alkenyl, C7-C9 aralkyl, C5-C7 cycloalkyl, C2-C6 acyloxyalkyl or C6-C10 aryl, or R8, if n is 2, represents C2-C12 alkylene, C6-C12 arylene, or a-CH2CH(ORl)CH2 group.
(IV) in which:
n represents 1 or 2;
R represents hydrogen or methyl;
R1 represents C1-C8 alkanoyl, C3-C5 alkenoyl, sorboyl, cinnamoyl, C2-C5 alkoxycarbonyl, or a group (R2)(R3)NCO-, in which R2 is C1-C12 alkyl, cyclohexyl, phenyl, or phenyl substituted by halogen, C1-C4 alkyl, or C1-C4 alkoxy and R3 is hydrogen, C1-C12 alkyl, cyclohexyl, or benzyl;
R7 represents hydrogen, C1-C12 alkyl, allyl, benzyl or C2-C6 alkoxyalkyl; and R8, if n is 1, represents hydrogen, C1-C12 alkyl, glycidyl, C3-C5 alkenyl, C7-C9 aralkyl, C5-C7 cycloalkyl, C2-C6 acyloxyalkyl or C6-C10 aryl, or R8, if n is 2, represents C2-C12 alkylene, C6-C12 arylene, or a-CH2CH(ORl)CH2 group.
2. The method according to claim 1, wherein R in formula IV
is hydrogen.
is hydrogen.
3. The method according to claim 1, wherein R1 in formula IV is a C2-C4 alkanoyl or C3-C5alkenoyl group.
4. The method according to claim 1 wherein the light stabiliser has the formula IV, wherein R and R7 are hydrogen, R1 is acetyl, and R8 is dodecyl.
5. The method according to claim 1, wherein the N-substi-tuted 2,2,6,6-tetraalkylpiperidine compound is used in an amount of 0.1 to 5% by weight, based on the solvent-free binder (coating resin).
6. The method according to claim 1, wherein another light stabiliser is additionally used.
7. The method according to claim 6, wherein the sum of all light stabilisers is 0.2 to 5% by weight, based on the solvent-free binder (coating resin).
8. The method according to claim 1, wherein the acid catalysed stoving lacquer is a high solids industrial lacquer.
9. An acid-catalysed stoving lacquer which is based on hot-cross-linkable acrylic, polyester or alkyd resins and which contains, as light stabiliser, at least one compound of the formula (IV) according to claim 1.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH8326/80-9 | 1980-11-10 | ||
| CH832680 | 1980-11-10 | ||
| CH427181 | 1981-06-29 | ||
| CH4271/81-8 | 1981-06-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196444A true CA1196444A (en) | 1985-11-05 |
Family
ID=25695099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000389590A Expired CA1196444A (en) | 1980-11-10 | 1981-11-06 | Light stabilization of acid-catalysed stoving lacquers of unsaturated poly-acrylics or polyesters |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0052073B1 (en) |
| BR (1) | BR8107241A (en) |
| CA (1) | CA1196444A (en) |
| DE (1) | DE3176368D1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4774332A (en) * | 1984-08-14 | 1988-09-27 | Sandoz, Ltd. | Piperidine containing stabilizer compounds |
| US5015682A (en) * | 1989-03-21 | 1991-05-14 | Ciba-Geigy Corporation | Oligomeric N-hydrocarbyloxy hindered amine light stabilizers |
| US5112890A (en) * | 1987-09-21 | 1992-05-12 | Ciba-Geigy Corporation | Stabilization of acid catalyzed thermoset resins |
| US5124378A (en) * | 1987-09-21 | 1992-06-23 | Ciba-Geigy Corporation | Stabilization of ambient cured coatings |
| US5286865A (en) * | 1989-03-21 | 1994-02-15 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
| US5359069A (en) * | 1989-03-21 | 1994-10-25 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5832642A (en) * | 1981-08-20 | 1983-02-25 | Adeka Argus Chem Co Ltd | Stabilized synthetic resin composition |
| EP0094343A1 (en) * | 1982-04-27 | 1983-11-16 | Ciba-Geigy Ag | Polyalkylpiperidine derivatives containing isocyanate groups |
| US4650870A (en) * | 1984-03-12 | 1987-03-17 | Ciba-Geigy Corporation | Substituted piperazinone light stabilizers |
| US4785102A (en) * | 1985-08-27 | 1988-11-15 | Ciba-Geigy Corporation | Photolytically cleavable, N-acylated sterically hindered amines |
| GB8907595D0 (en) * | 1989-04-04 | 1989-05-17 | Sandoz Ltd | Improvements in or relating to organic compounds |
| IT1247977B (en) * | 1991-06-04 | 1995-01-05 | Ciba Geigy Spa | STABILIZATION OF POLYMERIC ORGANIC MATERIALS BY MEANS OF SYNERGIC MIXTURES CONSISTING OF STERICALLY IMPEDED CYCLIC AMINES AND DERIVATIVES OF 3-PYRAZOLIDINONE OR 1,2,4, -TRIAZOLIDIN-3,5, -DIONE |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0002753B1 (en) * | 1977-12-30 | 1983-10-05 | Ciba-Geigy Ag | Stabilisation of heat-curable metallic enamel paints against the action of light, humidity and oxygen by the addition of polyalkylpiperidine derivatives |
| EP0006213B1 (en) * | 1978-06-21 | 1982-09-01 | Ciba-Geigy Ag | Light stabilization of acid catalysed stoving enamels |
| US4314933A (en) * | 1979-02-15 | 1982-02-09 | Ciba-Geigy Corporation | Method for light stabilization of two-layer uni-lacquer coatings |
-
1981
- 1981-11-04 EP EP81810441A patent/EP0052073B1/en not_active Expired
- 1981-11-04 DE DE8181810441T patent/DE3176368D1/en not_active Expired
- 1981-11-06 CA CA000389590A patent/CA1196444A/en not_active Expired
- 1981-11-09 BR BR8107241A patent/BR8107241A/en unknown
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4774332A (en) * | 1984-08-14 | 1988-09-27 | Sandoz, Ltd. | Piperidine containing stabilizer compounds |
| US5112890A (en) * | 1987-09-21 | 1992-05-12 | Ciba-Geigy Corporation | Stabilization of acid catalyzed thermoset resins |
| US5124378A (en) * | 1987-09-21 | 1992-06-23 | Ciba-Geigy Corporation | Stabilization of ambient cured coatings |
| US5015682A (en) * | 1989-03-21 | 1991-05-14 | Ciba-Geigy Corporation | Oligomeric N-hydrocarbyloxy hindered amine light stabilizers |
| US5286865A (en) * | 1989-03-21 | 1994-02-15 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
| US5359069A (en) * | 1989-03-21 | 1994-10-25 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
| US5442071A (en) * | 1989-03-21 | 1995-08-15 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
| US5574162A (en) * | 1989-03-21 | 1996-11-12 | Ciba-Geigy Corporation | Non-migrating 1-hydrocarbyloxy hindered amine derivatives as polymer stabilizers |
Also Published As
| Publication number | Publication date |
|---|---|
| BR8107241A (en) | 1982-07-27 |
| EP0052073A1 (en) | 1982-05-19 |
| DE3176368D1 (en) | 1987-09-24 |
| EP0052073B1 (en) | 1987-08-19 |
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| MKEX | Expiry |