DE1911290A1 - Process for the production of thermosetting coating compounds based on aminoplast-modified copolymers and their use for baking enamels - Google Patents

Description

DR. ELISABETH JUNG, DR. VOLKER VOSSIUS ₁ DlPL.-ING. GERHARD COLDEWEY PATENT LAWYERS IQI 19QO

. t MÖNCHEN 23 ■ S I EC E 8 S T RASSE Si ■ TELEFON 34 (087. TE LE G B AMM ADRESSE: INVENT / MDNCHCN

u.z. s ε 124 (BeAo) 5 MAR. 1969

CaBO 1-5 / 68

SOCIBTA ITALIANA BESIKE SpA Milan, Italy

"Process for the production of when-hardening coating compounds based on aminoplast-modified copolymers" and their "use for stoving enamels"

Priority: March 7, 1968, Italy, Mr. 13 623-A / 68

The invention relates to a process for preparing wftrxn curable coating compositions based on aninoplastmodifizierten copolymers. In particular, the invention relates to a process for the production of partial condensation products from a thermoplastic copolymer of α, α-unsaturated carboxylic acids or derivatives of such carboxylic acids and a thermosetting, alkylated aminoplast synthetic resin. Finally, the invention relates to the use of the coating compositions for stoving enamels.

It is known, coating compositions by mixing a Wanohärtenden alkylated aminoplast plastic resin »with a thermal

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plastic so-called Aerylat-Copolyflm-iaat ma "Ssen allylester of a d., p-unsaturated carboxylic acid, a compound which contains the group CH ₂ " CC, and / or "an allyl ester of a" u, B-unsaturated carboxylic acid to produce the " · Coating compounds are used as a carrier for printing inks or look ·, for example for coating ovens and XJÜhlscfcränkea and £ & nz in general for the production of lining · »or BtseSfcioatuxigen for surfaces that produce unluellehe borte? Ilrae when baking.

However, such mixtures have beetiamte Nacateil® · more complete is the consistency of some products, wi® £ _f Eeken produced from the coating compositions, never t t> estiinilg · This is probably due to changes in the properties of the mixtures during storage, back.

The object of the invention is a method genährleisten sur preparation of coating compositions from mixtures mis waxiohSrtenden alkylated aminoplast "> resins with thermoplaetieckes acrylate copolymers which retain their properties unchanged for a longer shelf life and resistance properties of products produced therefrom creating.

It has been found that the production of better thermosetting mixtures of the type mentioned is possible as a result of this “dees nan a mixture of the alkylated aminoplast synthetic resin with the copolymer! sat to a temperature above room temperature ₈ that is above 15 ⁰ C, heated. It is believed that this heat treatment is a partial condensation of the two components

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dt · Mixture causes, - where the alkylated Aainoplast-Eunsthars serves as a linkage.

Basically unsaturated carboxylic acid and / or an “ester or hydroxy substitute” of a C, B-unsaturated carboxylic acid and / or an “ester or hydroxyl substitute” of a C, B-unsaturated carboxylic acid was substituted by a thermoplastic copolymer -Kunathars is daduroh gekeenseiohnet "that nan sine LBsung of Geaicches eat sine fsspsratur above 15 ⁰ O erhitst to sur partial condensation of Copolyasrisats with the AainoplaBt resin * Preferably srfindungsf * - bMbb the Osaisch to 60 to HO ⁰ C over a period of 15 minutes to 8 hours hardened.

According to the invention, the alkylated plastic synthetic resin is partially condensed with the acrylate copolymer , which, surprisingly, improves the product in such a way that the heat-treated solution does not change its properties in the course of time. Another advantage of the invention process is that pigmented lacquers which are produced from the oversized boaeeen obtained have a greater brilliance than lacquers which are made from simple oils are manufactured according to the state of the art, even if

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high pigment concentrate tones are present.

The aminoplaat kunethar * used according to the invention are preferably condensate! onproducts of an aldehyde, especially formaldehyde, with urea, thiournet, melaain, bensoguanamine or dicyandiamide. The condensation is preferably carried out in the presence of aliphatic alcohols from 1 to 8 carbon atoms in the molecule, so that when the reaction is complete, the methylol groups in the aminoplast synthetic resin are in esterified form.

Particularly useful aminoplast synthetic resins are the condensation products of melamine and formaldehyde in a molar ratio of 1: 5 to 1: 6.8, the ratio of formaldehyde to aliphatic alcohol preferably being 1: 0.8 to 1.5, as well as the condensation products of urea and formaldehyde la molar ratio 1: 1.8 to 1 χ 2.4 alt a molar ratio of formaldehyde: aliphatic alcohol of i: 1 to 1: 1.5 *

According to the invention usable and preferred thermoplastic acrylate copolymers used are those of Arylvinylver compounds such as styrene, cC-methylstyrene and / or vinyl toluene, in an amount of 0 to 45 wt .- ^, λ _t ß-unsaturated carboxylic acids, such as acrylic acid, Methacrylic acid and / or itaconic acid, in an amount of 0 to 6 wt .- ^ ₁ hydroxyalkyl esters of <£, ß-unge sä made carboxylic acids, such as acrylic acid hydroxyethyl ester and / or acrylic acid hydroxypropyl ester and / or the corresponding esters of methacrylic acid, in an amount of 4 to 10 wt .- #, and esters of Λ, B-unsaturated carboxylic acids, the ester group

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contains aliphatic hydrocarbon radicals with 2 to β carbon atoms in the molecule, such as eater of acrylic acid and / or methacrylic acid, in an amount of 45 to 90 percent by weight. Dieeea therffloplaatiache acrylate copolymer can be prepared by copolymerization in suitable solvents such as xylene, butanol or ethylene glycol monomethyl ether at a temperature of 70 to 140 ⁰ C over a period of 50 to 30 * hours. As a polymerization catalyst, a fiisso compound or a peroxide, such as benzyl peroxide, can be used in an amount of preferably 0.3 to 3.0% by weight, based on the monomer mixture.

To carry out the inventive process, the alkylated aminoplast resin is preferably added in an amount of 10 to 40 parts by Jc, based on the copolymer _t with the Aorylat copolymer mixed, for example by mixing dea resin with a solution- of the copolymers in a solvent , which dissolves both constituents, such as xylene and / or butanol, and then the solution is ^{heated to a temperature above 15 °} C. for a long time until the constituents are partially condensed. The heating is preferably carried out for 15 minutes to 8 hours at a temperature of 60 to 110 ⁰ C. The resulting solution of the partially condensed thermosetting product can be stored for long periods of time without noticeably changing its properties.

Eb is believed to be due to the partial condensation of the thermoplastic acrylate copolymer with the alkylated

Aminoplast synthetic resin which promotes homogenization and

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This avoids the possibility of layer formation in mixtures that can be mixed with the sole and an XrttbuneT solution

If a übersug ouch the arfindungagaaUsa produced üb · * »sugsmasse at a temperature above 10O ⁰ C cured ao a fully networked paint film is obtained whose properties is good, regardless of the Legerungaseit well eind and its luster in particular much even when a high Pigeaatgehalt is present in the paint.

The invention is illustrated in more detail by the following examples. The ingredients used in the examples were prepared as follows.

Aminoplaat-gunstharg

1.730 parts by weight of 36 igea formalin were brought to a pH of about 8 and mixed with 0.424 parts by weight of VQiaain. The mixture was brought to boiling and maintained at boiling, the mass, until the content of freiem.Formaldehyd less ale about 6 wt. Was -f. The reaction mixture was 1.920 parts by weight. Sutanol and 1.7 parts by weight maleic anhydride and, where the Heaktionsgemi8ch · held about 60 minutes at 90 to 100 ⁰ C. The pH of the mixture was readjusted to about 8 and it has been condensed a further 30 minutes and then cooled. The aqueous phase was removed and the remaining reaction mixture was distilled under reduced pressure until a product having a viscosity of about 13,000 cB was obtained.

The aminoplast synthetic resin obtained had a color value of 15 on the Haze scale, an acid number below 0.3 and a content of

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Dry matter of about 67% by weight * Aorrlat copolysarate

Se a Gesieeh 6 $ by weight of xylene and 35 £ Osw.-jC fiuteaol in an old a stirrer, a BUokflusskühler and a "drip triohter equipped flask was placed and heated to about 109 ⁰ O" rhi t et. Through the dropping triohter, a monohydric acid was obtained from 36.1% by weight of styrene, 2.1% by weight of itaoomic acid, 15% by weight of aoryl acid ethyl ester, 36.1% by weight of methyl methacrylate and 9.9% 0 * w .-) C Metiiaoxylellurehydroxyaethylester added over a side period of about 2 hours. Over the same period of time, bensoyl peroxide was added to the catalyst in an amount of 1.5 parts by weight per 100 parts by weight of the monoergenic "

The copolymerization was carried out until about 12 hours a Copolyseriaat with a content of 49 GeWa-fC dry substance was obtained.

example 1

24 parts by weight of the Asinoplaet synthetic resin were added to 100 parts by weight of the solution made from xylene and butanol dissolved Copolyserisats suggest. Ee was at fiauatesperatur mixed and taken from an ark · The Gesisoh was then heated to 80 ° C and about 3 hours on this Temperature held. After heating it became clear obtained with the following properties «

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Gardner color value below 1 Traded on dry matter 49 »β Gew # - £ Gardner-Holdt viscosity Z + 1/3 Haze color value 80

Acid number

(on TrockenBUbBtanz) .14

A sample of the product as well as the sample obtained after mixing at room temperature were used with an extractor on a glass plate on a pile of 0.203 mm thick. The piles were left to stand at room temperature for 20 minutes until the solvent had evaporated left and then in an oven for 3 hours at 80 ° C warmed and allowed to cool.

The product prepared according to the invention gave a clear one Film, while the comparative sample produced a significantly cloudy film.

Example ^

Part of the coating composition prepared according to Example 1 was pigmented with rutile (TiO ₂ ) R 60 in a ratio of 0.8 part by weight of pigment to 1 part by weight of binder. The pigmented coating composition was in a solvent mixture of 55 wt .- ^ butanol, 11.6 wt. -4. Äthylenglykolmonomethylätheraoetat, 11.4 wt .- ^ an aromatic hydrocarbon mixtures s for stoving lacquers ( "Solvesso ¹¹¹⁵⁰⁾ was dispersed and 22 wt .- ^ C xylene and a dispersion of a spray viscosity of 18 up to 20" obtained TF4 at 20 ⁰ C. The dispersion was in

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two layers on top of each other on a ^H Ohioliim ^B plate. -

The coated plate was allowed to stand at Eaumtenperatur for 20 minutes to cool and then heated 30 minutes 150 ⁰ C.

It was a dry film with a thickness of 40 to 50 microns

obtain the following properties: -

Hardness according to Albert Koening (on glass) 150

Brilliance, gloss meter 60 ° 100 Erichsen deep drawing value. 4 mm

Impact strength less than 1 kg / cm

Surface appearance uniform and

shiny

A sample of the example 1 immediately after mixing Mixture prepared without heating was sub-comparison in treated the same way. Before application as a film, the sample had a dry matter content of 4715 wt Gardner-Holdt viscosity of 22. The surface of the sample cloudy.

After applying and curing as above, it was dry Film determines the following properties:

Hardness according to Albert Koening (on glass) 145 brilliance, gloss meter 60 ° ....... 91

Erichsen deep drawing value 1 mm

Surface appearance uneven

and matt

From the comparison experiment it emerges that there is an inventive geiaaas manufactured coating compound as such and to paint

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processed better properties than a Übersugsaaas · · gesäBS the prior art. -

- Patent claim -

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Claims (6)

Claims A process for preparing thermosetting überz ugemaei s by mixing of a thermoplastic copolymer! «Atm from an aryl vinyl compound, a Λ, β-unsaturated carboxylic acid and / or an ester or hydroxyalkyl ester of an et, ß-unsaturated carboxylic acid with a thermosetting alkylated aminoplast synthetic resin, characterized in that a solution of the mixture is heated to a temperature above 15 ⁰ C until partial condensation of the copolymer with the aminoplast synthetic resin. 2. The method according to claim 1, characterized in that the heating is carried out at 60 to 110 ^° C. for 15 minutes to 8 hours. 3 * Method according to claim 1 to 2, characterized in that the alkylated aminoplast synthetic resin in an amount of 10 to 40 percent by weight, based on the copolymer i eat. 4. The method according to claim 1 to 3, characterized in that the alkylated aminoplast synthetic resin a condensation product of an aldehyde with urea, thiourea, melamine, benzoguanamine or dicyandiamide is used. 5. The method according to claim 1 to 4, characterized in that ale copolymer is used, the sub 0 to 45 wt .- ^ of an aryl vinyl compound, 0 up to 6 wt .- ^ of an oc, ß-unsaturated carboxylic acid, 4 to 10 909843/15 7 4 BATH ORIGINAL. * .-- '■■ * 1 O «w.-jC« in ·· Hydroxyalkyl · · * · «· 1η · Γ 4L _t B- * mg-ättie% m Gart • Kur · and 45 to 90 Oew.-ji« in «· E» t * r · «ln« r «t OarbonaKur · h« ret ied. 6. Venrendun "d" r oversugeaftee "according to claims 1 bis ποτ Manufacture of baking enamels. 9098A3 / 157A BATH ORIGINAL