CH680667A5 - - Google Patents

Description

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CH 680 667 A5

description

The invention relates to the use of sterically hindered amines as light stabilizers (HALS) for stabilizing thermosetting acrylic lacquers (TSA), alkyd melamine lacquers (A / MF), 2-component polyurethane lacquers (2C-PUR) and thermoplastic acrylic - (TPA) paints.

The invention relates to a varnish containing a thermosetting acrylic resin, an alkyd-Me-lamin-formaldehyde resin, a 2-component polyurethane resin or resins that form a 2-component polyurethane resin, or a thermoplastic acrylic resin and a UV stabilizing amount of a compound of formula I.

S4 II)

R2 Rj wherein each Ri is independently -CH3 or -CH2 (Ci-4-alkyl) or both groups Ri form a group - (CH2) s-;

each R2 is independently -CH3 or -CH2 (Ci-4-alkyl) or both groups R2 form a group - (CH2) s-;

R is hydrogen, oxygen, Ci-8-alkyl or -COR5;

wherein R5 is -C (Ri3) = CH2, Ci-s-alkyl, phenyl, -NR7Rs, -CO-C6H5, -CH2-C6H5, -COOCi-12-alkyl or -COOH; R7 is hydrogen, Ci-12-alkyl Cs-e-cycloalkyl, phenyl, phenyl-Ci-4-alkyl or C1-12-aikylphenyl and Rs is hydrogen or Ci-12-alkyl; and R13 has the meaning given below; R4-NR13R14 is or a group of formula a

%

-N (R13 * - X —N (R13- ~ \ _ / N ™ "R (a)

J. Rn r2 2

wherein R13 is hydrogen or C-i-e-alkyl which is unsubstituted or monosubstituted by OH; R14 is hydrogen or unsubstituted or substituted by OH monosubstituted Ci-e-alkyl; and

X is C-i-12 alkylene.

In this specification, a varnish containing a thermosetting acrylic resin as a TSA varnish, a varnish containing an alkyd-melamine-formaldehyde resin as an A / MF varnish, a varnish containing a 2-component polyurethane resin or resins containing a 2- Form component polyurethane resin, contained, referred to as 2C-PUR lacquer and a thermoplastic acrylic resin containing lacquer called TPA lacquer.

If reference is made to a polyurethane resin in this specification, it includes resins that form a polyurethane resin.

Ri and R2 are preferably each -CH3.

Preferably R13 and Ru are independently hydrogen or C1-4 alkyl.

Preferred compounds of the formula I are those of the formulas II to IV

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CH 680 667 A5

CH.

R '- M) —NH -

C * 3 CH3

(CH? I NH

~ 1 -6

/ V "

.(H-*-

/ Sat,

CH3 w ,, 3

(II)

CH CH,

X ^ '

R 'N) - N

A *

CH ^ CHj yCH2 CH2 OH v "CH2 CH2 OH

(III)

wherein R 'is hydrogen, -CH3 or -COCH3 and R16 is Ci-6-alkyl (preferably n-C ^ tHg).

In formulas II to IV, R 'is preferably hydrogen.

According to the invention, an oven-drying TSA lacquer is also created which contains a thermosetting acrylic resin and a UV-stabilizing amount of a compound of one of the formulas II to IV defined above.

According to the invention, a coating is also created which is derived from a lacquer which is a thermosetting acrylic resin, an alkyd-meiamin-formaldehyde resin, a two-component polyurethane resin or resins which form a two-component polyurethane resin, or contains a thermoplastic acrylic resin and a UV stabilizing amount of a compound of formula I defined above.

A coating according to the invention is advantageously not acid-hardened, although it can be acid-hardened.

Thermosetting acrylic resins that can be used in a TSA varnish are those derived from Me laminate formaldehyde polyacrylate varnishes, more preferably those derived from a hydroxy group-containing polyacrylate resin and melamine formaldehyde.

Alkyd-melamine-formaldehyde (A / MF) resins (preferably 30:70 melamine / formaldehyde [1: 1] to Al-kyd) which can be used in an A / MF lacquer according to the invention are made from such selected which are derived from oil-modified polyester resins (oil-alkyd resins) and melamine resins; cross-linked polyacrylate and melamine resins; saturated polyester and melamine resins or self-crosslinking polyacrylate resins.

Polyurethane resins that can be used in 2C-PUR lacquers are selected from hydroxy group-containing polyester and / or polyacrylate resins, cured with aliphatic or aromatic isocyanates.

Thermoplastic acrylic resins that can be used in TPA paints are selected from thermoplastic acrylic resins.

The lacquers according to the invention can be used to produce metallic one- or two-layer coatings or uni-, one- or two-layer coatings. Preferably TSA and 2C-PUR varnishes are used to make two-layer coatings, and melamine alkyd resins and acrylic-melamine resins are preferably used to make single-layer coatings.

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CH 680 667 A5

If the lacquers according to the invention are used for two-layer coatings, the lacquer which contains the compound of the formula I is preferably the top layer, which is preferably a clear layer.

Preferred metallic lacquers are those which are derived from TSA resins, in particular those which are derived from crosslinked polyacrylate resins with melamine-formaldehyde resins, etherified with butanol, and also 2C-PUR resins, such as hydroxyl-containing polyacrylate resins, hardened with aliphatic isocyanates .

The TSA, A / MF, 2C-PUR and TPA resins are described in - "Textbook of paints and feeds" - H. Kittel, (Berlin) Volume I, Part 2 and in US Patent 3,062,763; the content of both is introduced here as a reference.

The compounds of formula I can be used alone or in combination with other stabilizers, for example antioxidants. Examples include hindered phenols, sulfur- or phosphorus-containing compounds or mixtures thereof, benzofuran-2-ones, indolin-2-ones and hindered phenols such as β- (4-hydroxy-3,5-ditert.butylpheny!) Propionyl stearate, methane tetrakis (methylene-3- (3 ', 5'-ditert.butyl-4'-hydroxy-phenyl) propionate), 1,3,3-tris (2-methyl-4-hydroxy-

5-tert-butyl-phenyl) butane, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -1,3,5-triazinyl-2,4,6-

(1 H, 3H, 5H) -trione, bis (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiol terephthalate, tris (3,5-di-tert-butyl-4-hydroxy) -benzyl) -isocyanurate, the triester of ß- (4-hydroxy-3,5-ditert.butylphenyl) -propionic acid with 1,3,4-tris- (2-hydroxyethyl) -5-triazinyl-2,4 , 6- (1H, 3H, 5H) -trione, bis- (3,3-bis- (4'-hydroxy-3'-tert-butylphenyl) -butyric acid) glycol ester, 1,3,5-trimethyl -2,4,6-tris- (3,5-ditert.butyl-4-hydroxy-

benzyl) benzene, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenyl) terephthalate, 4,4-methyene-bis- (2,6-ditert.butylphenol), 4, 4'-butylidene-bis- (tert-butylmetacresol), 2,2'-methylene-bis- (4-methyl-6-tert-butyl) phenol.

Sulfur-containing antioxidant costabilizers that can be used include, for example, distearyl thiodipropionate, dilauryl thiodipropionate, methane tetrakis (methylene-3-hexylthiopropionate), methane tetrakis (methylene-3-dodecylthiopropionate) and dioctadecyl disufide.

Phosphorus-containing costabilizers include, for example, trinonylphenyl phosphite, 4,9-di-stearyl-3,5,8,10-tetraoxadiphosphaspiroundecane, tris (2,4-ditert.butylphenyl) phosphite and tetrakis (2,4-ditert .butylphenyl) -4,4'-biphenylene diphosphonite.

Other additives such as aminoaryl compounds and UV absorbers and light stabilizers, e.g. substituted 2- (2'-hydroxyphenyl) benzotriazole, 2-hydroxy-benzophenone, 1,3-bis (2'-hydroxybenzoyl) benzene, salicylates, cinnamates, benzoates and substituted benzoates and other sterically hindered amines (HALS) and Oxalic acid diamides can be used. Other known types of additives can also be added, e.g. Flame retardants and antistatic agents.

Preferably a compound of formula XX

wherein R30 is C6-22 alkyl or C & 22 alkoxy;

R31 and R32 independently of one another denote hydrogen, Ci-s-alkyl, Ci-12-alkoxy, Ci_12-alkylthio, phenoxy or phenylthio, with the proviso that only one of R31 and R32 is alkylthio, phenoxy or phenylthio and R33 is hydrogen or Ci_6-alkyl is added to a compound of formula I.

The amount of a compound of the formula I which can be used in a lacquer according to the invention is preferably 0.1 to 8% by weight of the solids in the lacquer, more preferably 0.5 to 5%.

The invention will now be illustrated by the following examples, where all parts and percentages relate to weight and all temperatures to ° C, unless the contrary is indicated. The amount of light stabilizer is based on the weight of solids in the paints.

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CH 680 667 A5

Example 1.

A metallic two-layer coating containing a base coat and a clear top coat can be made from the following paints.

Base coat varnish

18.75%

clear top coat 1, defined below (50% solids)

51.75%

Cellulose acetobutyrate solution (20%),

commercially available as Cellit BP 500

13.54%

n-Bulyl acetate

6.45%

Xylene

5.15%

Ethylene glycol acetate

0.26%

Anti-sedimentation medium: Aerosil 200

3.85%

a 65% aluminum paste in ethylene glycol acetate,

commercially available as Alcoci 7530

0.25%

Phthalocyanine Blue (C.I. Pigment Blue 15: 1)

100.00%

(the ratio of pigment to aluminum is about 1:10)

Clear top coat 1 is formulated as follows:

80.00% of an acrylic resin, commercially available as Viacryl SC344 - 50% in a solution from Xylo! and n-butanol (4: 1 ratio)

13.90% melamine resin, 4.10% n-butanol and

2.00% of a diluent, commercially available as Byketol OK.

Process for the production of the two-layer lacquer coating

A primed 10 x 30 cm piece of aluminum gets wet in wet with the base coat and then the clear coat, the 1% of a compound of formula 1a

The piece of aluminum treated in this way is then oven-dried at 140 ° C. for 35 minutes.

Examples 2 and 3

Example 1 is repeated, 1% of one of the compounds of the formulas 2a to 3a being used instead of the compound of the formula 1a.

Example 2

CH, CH,

m) —HH - (CHji NH

/ r 6

CHj CH3

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CH 680 667 A5

Example 3

ch, ch,

- </ 3

(3a)

—NH -

C4 «9

ch3 ch3

Example 4

Examples 1, 2 and 3 can be repeated, with 2.2% (active material) of the monobutyl ester of maleic acid being added to the clearcoat and instead of oven drying at 140 ° for 35 minutes, the paint is acid-cured at 90 ° C for 30 minutes.

Example 5

A two-layer coating in which the top layer is 2C-PUR can be produced as follows:

A base coat varnish is produced as in Example 1.

A clear coat is made as follows:

The first component of the 2C-PUR contains

44.1% of an hydroxy resin-containing acrylic resin (OH number about 150) commercially available as Macrynal SM 510 N, a 60% solution in xylene and ethylene glycol acetate (ratio 4: 1)

35.2% of a dilution mixture of methyl ethyl ketone and xylene (1: 1)

3.0% Byketol Speziai: commercially available leveling agent (containing silicone)

The second component contains

17.7% of an aliphatic polyisocyanate, commercially available as Desmodin N (which is a 75% solution in 4: 1 xylene / ethylene glycol acetate).

The second component is then added to the first component and wet mixed (as indicated above). 1% of the compound of formula 1a is added to the 2C-PUR thus formed.

The base and clear layers (in the same thickness as specified in Example 1) are applied wet on wet to an aluminum piece as described in Example 1. The paints are then oven dried at 80 ° C for 35 minutes.

Example 5 can be repeated using 1% of one of the compounds of formulas 2a-3a (defined above).

Claims (8)

Claims 1. Lacquer containing a thermosetting acrylic resin, an alkyd-melamine-formaldehyde resin, a 2-component polyurethane resin or a thermoplastic acrylic resin and a UV-stabilizing amount of a compound of the formula I. wherein each Ri is independently -CH3 or -CH2 (Ci_4-alkyl) or both groups Ri form a group - (CH2) 5-; each R2 is independently -CH3 or -CH2 (Ci_4-alkyl) or both groups R2 form a group - (CH2) 5-; R is hydrogen, oxygen, Ci_e alkyl or -COR5; where R5 -C (Ri3) = CH2, Ci-e-alkyl, phenyl, -NR7R8, -CO-C6H5, -CH2-C6H5, -COOCi-12-alkyl or - 6 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 CH 680 667 A5 or is -COOH; R7 is hydrogen, Ci-12-alkyl, Cs-6-cycloalkyl, phenyl, phenyl-Ci-4-alky! or is C1-12 alkylphenyl and Rs is hydrogen or Ci_i2 alkyl; R13 has the meaning given below; R4 is -NR13R14 or a group of formula a -NO 13 * —N (R) 13 (*) wherein R13 is hydrogen or C-i-e-alkyl which is unsubstituted or monosubstituted by OH; R14 is hydrogen or Ci-6 alkyl which is unsubstituted or monosubstituted by OH; and X is Ci-12 alkylene. 2. Lacquer according to claim 1, wherein in the compound of formula I each of R 1 and R 2 is -CH 3, 3. Lacquer according to claim 1, wherein the compound of formula I is selected from those of formulas to IV -NH - (CHJ NH - ch3 ch3 • 1-6 (ii) ch3 ch3 r 'n ch3 ch3 ycw2 ch2 oh <v-ch2 ch2 oh (iii) r'— n n- r 16 : h3 ch3 (iv) where R 'is hydrogen, -CH3 or -COCH3 and crack is Ci_6-alkyl. 4. Lacquer according to one of claims 1 to 3, containing resins which form a two-component polyurethane resin. 5. oven-drying lacquer according to claim 3, characterized by a thermosetting acrylic resin and a UV-stabilizing amount of a compound according to one of the formulas II to IV defined in claim 3. 6. Coating produced with a lacquer which contains a thermosetting acrylic, an alkyd-melamine-formaldehyde, a polyurethane resin or a thermoplastic polyacrylic resin and a UV-stabilizing amount of a compound of the formulas) I according to claim 1. 7. A coating according to claim 6 which is not acid hardened. 8. A coating according to claim 6, which is acid-cured, the compound of formula I being one of the formulas II, III or IV defined in claim 3. 7