DE1258001B - Stoving and enamel varnish - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

C09d

German class: 22h -3

1258 001
S86582IVc / 22h
August 6, 1963
4th January 1968

Resin-containing paint components made from thermosetting acrylic resins are often of a certain disadvantage, for example when they are used in stoving enamels. These disadvantages exist, for example, in a high baking temperature and a bad odor during baking.

The paints according to the invention have better chemical and mechanical properties and a better color retention if stoved for too long.

The invention relates to stoving and enamel paints on the basis

1. an organic solvent as well

2. a polymer or copolymer of acrylic acid, methacrylic acid, ethyl acrylate, acrylamide, Styrene, vinyl toluene and formaldehyde, which by reaction with a polyglycidyl ether has been modified by 2,2-bis (4'-hydroxyphenyl) propane,

3. an alkyd resin

a) a polycarboxylic acid, its anhydride or mixtures thereof,

b) a polyhydric alcohol, an epoxy compound or mixtures thereof and

c) one or more aliphatic monocarboxylic acids and optionally

4. a melamine formaldehyde resin,

which are characterized in that they contain alkyd resins which are residues of aliphatic monocarboxylic acids (3, c) which have a tertiary or quaternary carbon atom in the α-position to the carboxyl group have included.

Acrylic resin paints are known, for. From French patent specification 1,162,967; with those in the Table on page 9 listed condensation products with epoxy resins of an epoxy equivalent weight from 400 to 525, however, components 3 and 4 from the stoving enamels according to the invention are missing. Also in British Patent 842,641, Example X and Examples XII and XIV are with the products just mentioned from page 9 of the French patent, identical paints are described. Components 3 and 4 are also missing here.

There is no numerical comparison of the properties of the cured films, because the information on hardness, impact resistance and gloss of the paint films according to various test methods were determined. Although z. B. between pencil hardness and hardness according to B u c h h 01 ζ or zwisehen Impact strength, indicated on the one hand in millimeters according to Erichsen and on the other hand in kilograms. and enamel varnish

Applicant:

Shell International Research

Maatschappij N.V., The Hague

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse
and Dr. E. Frhr. v. Pechmann, patent attorneys,
8000 Munich 90, Schweigerstr. 2

Named as inventor:

Robert John Turner,

Egham, Surrey (Great Britain);

Dim Baars,

Eduard Jules Willem Vogelzang,

Delft (Netherlands)

Claimed priority:

Great Britain 8 August 1962 (30 345)

gram / meter or inch / pound, as a first approximation, there are relations that allow a person skilled in the art to Making a rough comparison, however, prohibits numerical comparisons Reasons of accuracy. Only the data on the chemical resistance of the stoving enamels of the invention from Table II can be used to demonstrate the technical progress compared to the products from French patent specification 1,162,967 and British patent specification 842,641 will. While there z. B. the alkali resistance (3%) does not exceed 100 hours or for the products only a salt water (250 hours), moisture (1000 hours) and detergent resistance over 150 or 750 hours is demonstrated, show the stoving enamels according to the invention even after 14 days of exposure 5% alkaline and acidic (inorganic and organic) solutions still have very good resistance values.

The thermosetting acrylic resin is defined as a polymer or copolymer of acrylic acid and / or methacrylic acid or its derivatives. The said polymer or copolymer can be in

709 717/615

transform into an infusible and insoluble state.

Examples of thermosetting acrylic resins are copolymers of acrylic acid, acrylamide as well Methacrylic acid with styrene. Preferred thermosetting acrylic resins are polymers or copolymers which contain the following groups bound to the polymer structure:

ίθ

C-

NH-CH ₂ OR NHCH ₂ OH

I / O I / O

\ OC ₂ H ₄ OH ^ O-allyl

or C;

«Ο

• epoxyalkyl

Are preferred

ίθ

\ - CH ₂ OR,

bound to the polymer backbone.

-Groups

30th

A preferred mixed polymer of acrylamide is made from acrylamide and acrylic acid, methacrylic acid, Styrene and vinyl toluene. Used acrylamide in an amount of 3 to 25 percent by weight of the interpolymer is used, a good state of crosslinking is achieved.

Other preferred thermosetting acrylic resins are made by modifying a copolymer of Acrylamide with

-C

^X NH - CH ₂ OH

-Groups

45

produced in the molecule by reaction with an epoxy resin according to US Pat. No. 2,870,117.

The monocarboxylic acids present as residues in the alkyd resins are those which are preferred by reaction of olefins or paraffins with formic acid or with carbon monoxide and water are obtained and preferably contain at least 9 carbon atoms in the molecule.

For example, alkyd resins can be used, which by reacting polycarboxylic acids and / or their anhydrides, polyhydric alcohols and epoxyalkyl esters of branched monocarboxylic acids were obtained with each other or vice versa by first two or more of the Components are reacted with one another and the others added at a later point in time will.

Thus, in a first stage, a polycarboxylic acid and / or its anhydride with polyhydroxy and / or Epoxy compounds and branched monocarboxylic acids are implemented, resulting in the conversion with Epoxyalkyl esters of monocarboxylic acids followed, optionally in the presence of a polyhydroxy compound.

Suitable polycarboxylic acids are aromatic and aliphatic dicarboxylic acids and Diels-Adler adducts of maleic acid with dienes. Tricarboxylic acids can also be used, if appropriate two or more of these acids together. The anhydrides of these acids are preferably used.

Such polyhydroxy or epoxy compounds are preferably used in which three or more hydroxyl equivalents per molecule are included, with one epoxy group being equivalent to two Hydroxyl groups is, if appropriate, two or more of these compounds together. So can about trivalent hydroxyl compounds are used together with divalent hydroxyl compounds will.

Examples of hydroxy compounds are glycerol, pentaerythritol, trimethylolpropane and 1,2,6-hexanetriol. Examples of epoxy compounds are glycidol and diepoxybutane. Other examples are mixtures of glycerine with diethylene glycol, of pentaerythritol with dipropylene glycol and of glycidol with dipropylene glycol. For making polyesters that contain three hydroxyl groups is a functionality of at least three important.

The paints according to the invention can also be a melamine-formaldehyde resin as a third component contain.

In the paints according to the invention, the weight ratio of the alkyd resin to the thermosetting resin is Acrylic resin preferably between 60:40 and 40:60, although higher or lower Relationship may exist. If the paint also contains a melamine-formaldehyde resin, then is the amount of melamine-formaldehyde resin is preferably between 10 and 20 percent by weight of the overall preparation.

The lacquers according to the invention can be used for the production of enamels, for example pigmented enamels. Such enamel can be sprayed on without difficulty up to a thickness of 25 to 30 μ. The enamel is generally baked ^{at 150 or 180 ° C. for 30 minutes.}

By combining alkyd resins with an acrylic resin, excellent hardness and good mechanical properties achieved. Enamel with an additional content of a melamine-formaldehyde resin are harder. The masses have excellent resistance to a Discoloration and chemicals as well as high color fastness in case of too long heating during the burn-in process.

Buchholz hardness was measured according to DIN 53153. The gloss of the lacquer surfaces on glass plates was determined by optical comparison using a 45 ° long gloss meter with a black one Standard glass plate (optimal value = 100) determined. The impact strength was measured with the Erichsen apparatus certainly. The results are expressed in millimeters penetration depth (ball diameter: 20 mm) at which no cracking occurs in the lacquer coating (maximum value = 7). It was both the Impact resistance on the lacquer-coated front

(referred to as »Direct« in the tables) as well as that caused by the ball falling onto the back of the 0.5 mm thick, degreased metal test plate was determined.

The deepening according to E r i c h s e η was degreased according to DIN 5356 on 0.5 mm thick Steel plate measured.

The chemical resistance was determined to degreased cold rolled steel plate by immersion at 23 ⁰ C for 14 days.

Resistance is expressed in values from 1 to 10, with 10 being the optimal value.

The scratch resistance of the stoving lacquers was determined on layers of lacquer on small glass plates as follows: A hard steel pin with a weight that can be varied from 0 to 1000 g is passed over the paint surface. The scratch resistance, for which the critical value is that at which the surface is not yet damaged is expressed in 100 g values from 0 to 10, where the value 0 corresponds to the unloaded dead weight of the steel pin. A value of 2 means very good scratch resistance for stoving enamels, 1 still good scratch resistance.

Manufacture of the alkyd resin

25th

The alkyd resin A is a resin which was prepared from the glycidyl esters of branched monocarboxylic acids having 12 to 14 carbon atoms with phthalic anhydride at 25 ⁰ C a viscosity of 550 poise, a specific gravity of 1.18 and an acid value of 4 to 7 mg KOH / gram.

35

Production of the copolymer

The acrylic resins Bi and B2 are resins made from ethyl acrylate, acrylamide and styrene, which compounds have been copolymerized with formaldehyde and modified with the polyglycidyl ether of 2,2'-bis (hydroxyphenyl) propane, said resins having the following properties had, when applied together with 0.7 parts by weight of rutile pigment in the form of a 30 μ thick film and dried for 30 minutes at 18O ⁰ C.

Tabel

Buchholz
hardness Shine*) Impact resistance
back game Penetration
depth % kg mm Bi
B ₂ > 125
> 125 75
81 22.7
6.8 6.8 *) Measured on a 45 ° long gloss meter. at

Lacquers were produced in which a quantitative ratio according to Table 1 was present. In a Alkyd resin A dissolved in xylene became titanium dioxide as a pigment in an amount of 80% by weight ground the solution in a mixing roller. With stirring in a mixing roll, a solution of an epoxy-modified acrylic resin was obtained Bi or Ba in xylene with a solution of one Melamine-formaldehyde resin C mixed in xylene. The two solutions were then used together mixed and the viscosity of the mixture by adding an appropriate amount of a mixture adjusted from 4 volumes of xylene to 1 volume of butanol to a spray viscosity.

The mixture was then sprayed on to form an enamel, allowed to dry and well done Heated to 180 ° C for 30 minutes.

The following tables contain the results obtained with different amounts of resin A, Bi (B2) and C were obtained. The tables also contain the results with Mixtures of Resins A and Bi (B2) alone were obtained.

Table I.

Mechanical properties of the enamels of alkyd-acrylic resin systems with or without melamine-formaldehyde resins

Baking: 30 minutes at 180 ^° C

Alkyd Melamine-
Shape- acrylic Weight
relationship Buchholz
T-iot-tf ¹ shine Impact resistance
(E richsen) in mm direct mandrel Cupping after
E ri ch s s Shine at
1 "TUa ₁ - Scratch resin aldehyde-
resin resin A: C: B! respectively.
A: B ₁ FIaI LC
DIN 53153 % back 4Va bend in mm
DIN 53156 U UCi-
burn-in strength A. C. Bi 72:18:10 125 96 21/2 5 1/16 FP 7.5 88 0 A. C. Bj 64:16:20 > 125 94 2 51/2 1/16 FP 7.0 88 0 A. C. Bi 48:12:40 > 125 90 31/2 6I / 2 1/16 p 7.0 86 0.5 A. C. Bi 32: 8:60 > 125 90 5 6V2 1/16 p 7.0 84 0.8 A. C. Bi 16: 4:80 > 125 89 5 II / 2 1/16 p 6.7 82 1.2 A. - Bi 80:20 91 100 <1 7th 1/16 p. 8.1 100 <0 A. - Bi 60:40 > 125 97 5 6V ₂ 1/16 p 7.3 88 0 A. - B ₁ 40:60 > 125 94 51/2 61/2 1/16 p 7.3 95 0.5 A. - B ₁ 20:80 > 125 93 6th 1/16 FP 7.2 87 0.8

7th

Table II

Chemical and color fastness of enamels made from alkyd-acrylic resin systems with and without melamine-formaldehyde resins

Baking: 30 minutes at 180 ^° C

Alkyd Melamine-
Shape- acrylic Weight
relationship : 18: 10 Sulfur-
acid Sodium-
hvdroxvd vinegar
acid hydrochloric acid Discoloration for 3 days lipstick resin aldehyde- resin ArOB ₁ or 16:20 5% 5% 5% 5% very weak rlarz : 12: 40 mustard no A. C. Bi 72 8:60 6 to 7 9 7th 5 no no A. C. Bi 64 4:80 8th 9 8th 4 to 5 no no A. C. Bi 48 20th 7th 9 to 10 8th 5 to 6 no no A. C. Bi 32 40 8th 9 7th 6th no moderate A. C. Bi 16 60 9 9 3 to 4 5 no weak A. - Bi 80 80 9 6th 6th 5 no very weak A. - Bi 60 7th 8th 7 to 8 6th no no A. - Bi 40 9 8th 7 to 8 6th no A. Bi 20th 8th 9 • 5 5 no

Table III

Mechanical properties of enamels of alkyd-acrylic resin systems with and without melamine-formaldehyde resin

Branding: 30 minutes at 150 ⁰ C

Alkyd
resin Melamine-
Shape-
aldehyde-
resin acrylic
resin Weight
relationship
AiCrB ₁ or
A: B ₂ 18:10 Buchholz
hardness
DIN 53153 shine
% Impact
(Erichs
back branchiness
en) in mm
direct mandrel
bend
mm Cupping after
E ri ch s s
in mm
DIN 53156 A. C. B ₂ 72 16:20 111 > 100 1 2 6.35 F 7.9 A. C. B ₂ 64 12:40 105 > 100 1 2Vs 6.35P 7.4 A. C. B ₂ 48 8:60 121 > 100 <1 2 6.35 F 7.2 A. C. B ₂ 32 4:60 108 > 100 <1 2 6.35 F 7.3 A. C. B ₂ 16 20th 121 > 100 1V2 21/2 6.35 F 7.6 A. - B ₂ 80 40 84 > 100 <1 1 6.35 F 8.9 A. - B ₂ 60 60 105 > 100 <1 2 6.35 P. 8th A. - B ₂ 40 80 105 > 100 1V2 2V2 6.35P 7.5 A. - B ₂ 20th 93 > 100 <1 IVa 6.35 F 4.6

Table IV

Mechanical property in enamels of alkyd-acrylic resin systems with and without melamine-formaldehyde resin

Branding: 30 minutes at 18O ⁰ C.

Alkyd
resin Melamine-
Shape-
aldehyde-
resin acrylic
resin Weight
relationship
ArCrB ₁ or
ArBi Buchholz
hardness
DIN 53153 shine Beat
(Erichse
back sturdiness
n) in mm
direct mandrel
bend
mm Cupping after
Erichs e η
in mm
DIN 53156 Shine at
above-
burn-in A. C. B ₂ 72:18:10 103 100 IV2 3V ₂ 3.175 P 7th 95 A. C. B ₂ 64:16:20 114 > 100 IV2 3V ₂ 3.175 P 6.5 94 A. C. B ₂ 48:12:40 121 100 2 4th 6.35 P. 6.1 94 A. C. B ₂ 32: 8:60 100 > 100 2V2 4V ₂ 3.175 P 5.6 96 A. C. B ₂ 16: 4:80 114 > 100 2V2 4th 6.35 F 5.7 96 A. - B ₂ 80:20 74 > 100 <1 1 6.35 P. 8.2 99 A. - B ₂ 60:40 89 > 100 IV ₂ 3 3.175 P 7.9 98 A. - B ₂ 40:60 108 > 100 21/2 4th 6.35 P. 6.9 97 A. - B ₂ 20:80 114 > 100 2 5 6.35 P. 6.5 96

Claims (4)

Patent claims: 1. Stoving and enamel based varnish 1. an organic solvent as well 2. a polymer or copolymer of acrylic acid, methacrylic acid, ethyl acrylate, Acrylamide, styrene, vinyl toluene and formaldehyde, which by reaction with a polyglycidyl ether of 2,2-bis (4'-hydroxyphenol) propane has been modified, 3. an alkyd resin a) a polycarboxylic acid, its anhydride or mixtures thereof b) a polyhydric alcohol, an epoxy compound or mixtures thereof and 10 c) one or more aliphatic monocarboxylic acids and optionally 4. a melamine formaldehyde resin,
characterized in that they contain alkyd resins which contain residues of aliphatic monocarboxylic acids (3, c) which have a tertiary or quaternary carbon atom in the α-position to the carboxyl group. 2. Stoving and enamel paint according to claim 1, characterized by a weight ratio of Acrylic resin to alkyd resin between 60:40 and 40:60. Considered publications:
German Auslegeschriften No. 1060596,1118911; British Patent Nos. 842,641, 857,956;
French Patent No. 1,162,967;
Belgian patent specification No. 590 970. 709 717/615 12.67 © Bundesdruckerei Berlin