DE2245110B2 - USE OF UNSATURATED POLYESTER MATERIALS FOR THE PRODUCTION OF COATINGS - Google Patents

Description

/ A

A.

or

HIGH,

HIGH,-

CH, -OH

the presence of the UV sensitizer is responsible is made. Another disadvantage is it. that filler-containing fillers, especially with larger ones Layer thicknesses than 100 μ, cure incompletely, so there are defects such as cracking or peeling phenomena during use appear.

It is known that these disadvantages can be avoided by curing by infrared rays can (DT-OS 20 29 657). This type of hardening is particularly useful for clear coats, pigmented paints and highly filled fillers are suitable. However, the drying times are longer than with UV curing.

These longer irradiation times cause the substrate to heat up to an undesirable extent, which often leads to the formation of stress cracks. It was found that when using conventional Polyester the irradiation times cannot be shortened. The paint films then do not harden at all or only harden incomplete. This has the consequence that the films swell or even dissolved on treatment with xylene will.

From DT-PS 9 53 117 and 9 34 889 it is known Diols of the general formula

HIGH,-

-r-CH, OH

consists.

2. Use of unsaturated polyester compositions according to claim 1, characterized in that 70 to 100 mol percent of the diol component is composed of a diol of the general formulas A and B, respectively consists.

and

The invention relates to the use of unsaturated polyester compositions consisting of

1. an unsaturated polyester

2. one with 1. copolymerizable vinyl monomers

3. an activator system

4. Usual auxiliaries and additives

for the production of coatings, which by curing with infrared rays with a wavelength of 1 to 5 μ can be obtained.

It is known that unsaturated polyester resins are more suitable as molding and coating compounds after addition Initiators and accelerators at room temperature for hardening and coating wood, glass as well Stone slabs used to graze. The polyester compositions can also be used after the addition of fillers Leveling compounds can be used. A significant reduction in curing times to stack and Sandability of the coated surfaces is achieved through the use of UV rays and through the addition suitable UV sensitizers possible. In particular, clear lacquers or glazing can be achieved by means of UV rays colored lacquers are hardened.

The unsaturated polyester resins cured with UV rays, however, have the disadvantage that light-colored pigmented ack can yellow, for which HO-CH,

-CH, OH

to be used for polyester production. However, it cannot be inferred from these patents that just such polyesters are particularly good for curing

with the help of infrared radiators are suitable.

The object of the invention was, by using polyesters of suitable composition, 'Jberzüge to produce with good properties, which are obtained by curing by infrared radiators can, and where the disadvantages of the Prior art can be avoided.

This object was achieved in that the diol component of the unsaturated polyester was 1 to 40% up to 100 mole percent from a diol of the general

so formula

A. HO-CH ₂

CH ₂ -OH

or

B. HO -CH,

-CH, OH

consists.

The diols according to the invention are preferably used in amounts of 70 to 100 mol percent.

For the unsaturated polyesters according to the invention, fumaric acid is usually used for the acid component

22 45 I 10

acid, maleic acid or maleic anhydride, furthermore Itaconic acid or citraconic acid are also used. To / u 5% of the young and old eyed. copolymerizable Dicarboxylic acids can be replaced by saturated dicarboxylic acids, such as above all o-phthalic acid or o-Ph: anhydride, also isophthalic acid, succinic and adipic acid, tetrachloric or tetrabromophthalic acid or hexachlorendomethylenetetrahydrephthalic acid or their anhydrides be replaced.

In addition to the diols according to the invention, the diols listed below are also suitable for Polyester production:

Ethylene glycol (1,2), propanediol (1,3), butanediol (1,4) or hexanediol (1,6) as unbranched, ether group-free Diols; Propanediol (1,2), butanediol (1,2) or butanediol (1,3), also neopentyl glycol as branched chain ether group-free diols; unbranched-chain diols containing ether groups are particularly suitable Diethylene, also triethylene or tetraethylene glycols: as branched-chain ether-group-containing, before all dipropylene glycol or tripropylene glycol.

As unsaturated, copolymerizable vinyl ionomers the usual ones such as styrene, substituted styrenes such as tert.-butylstyrene or α-methylstyrene are suitable; also mixtures of the latter with styrene. Other ethylenically unsaturated monomers that in combination with styrene in amounts of less than 50 percent by weight, based on the monomer mixture, can be used are lower (Ci-Gi) -alkyl esters of acrylic acid or methacrylic acid and halogenated styrenes such as chlorostyrene, dichlorostyrene, and also diallyl phthalate.

The unsaturated polyesters are produced at temperatures from 150 to about 250 ^° C. by customary azeotropic or melt condensation of the components. In general, the diols are used in an approximately 2 to 10% molar excess over the dicarboxylic acids. However, the molar ratio of diols and dicarboxylic acids is not critical. The acid numbers of the unsaturated polyesters are generally between 10 and 70, preferably 20 to 50, in particular 25 to 40. Accordingly, the molecular weight, which is not critical to the invention, is between 550G and 800, preferably between 3000 and 10OC, in particular at 2500 and 1500.

Catalysts which form free radicals, such as diacyl peroxides, e.g. B. dibenzoyl peroxide, Dilauryl peroxide, peresters such as tert-butyl perbenzoate, Hydroperoxides such as cumyl or tert-butyl hydroperoxide, Ketone peroxides such as methyl ethyl ketone or cyclohexanone peroxides are particularly suitable the peroxydicarbonates, especially those with 3 to 6 carbon atoms in the alkyl radical, such as. B. Diisopropyl peroxydicarbonate, Di-terL-butyl peroxydicarbonate or dicyclohexyl peroxydicarbonate, can be used in amounts of 0.1 to 3 percent by weight. Likewise is the Curing accelerators such as tertiary, aromatic amines or cobalt salts can be added.

The polyester compositions can also be conventional polymerization inhibitors, for example hydroquinone, tert-butylcatechol, benzoquinone, di-tert-butylbenzoquinone and the like, generally about 0.001 to about 0.1 percent by weight, based on the total mixture, contain.

Further auxiliaries and additives can be fillers, pigments, paraffin, thixotropic agents and / or light stabilizers be.

The polyester compositions according to the invention are distinguished by a number of good properties: In addition to good general properties, IR curing quickly dries and dries good curing of the coatings achieved. The drying time depends essentially on the one used Amount of diols according to the invention.

During curing, the drying times depend on the proportion of the polycyclic diol according to the invention Polyester from: When using 0.5 percent by weight peroxide, based on the polyester molding compound, you can with a diol content of 40 mol percent of tricyclodecane dimethano! Drying times of approx. 3 minutes, with a proportion of approx. 60 mol percent even drying times can be achieved in less than 1 minute. It is even possible to achieve these short drying times to reduce the additional use of cobalt salts even further.

As the statements show, the polyester compositions according to the invention can be prepared with the aid of IR rays can be processed easily and quickly. The curing is very good, so that produced according to the invention Coatings are not affected when stored in xylene. In contrast, accordingly cured polyester coating compositions whose polyesters contain only 1,2-propanediol as a diol Xylene treatment completely dissolved ·.

Examples

A polyester resin was applied to glass plates (17 cm 7.5 cm) with a film applicator in a Layer thickness of 100 μ applied, one hour at Pre-dried at room temperature and then with an IR heater type H 8 from HERAEUS hardened. The distance between the radiator and the paint film was 45 cm.

Experiment a contains 0.5 percent by weight of isopropyl peroxide carbonate, Experiment b contains 0.5 percent by weight isopropyl peroxide carbonate with 1 percent by weight a cobalt octoate solution with a cobalt content of 1%.

The results obtained in Tables I and II were achieved with the polyesters I to IV and A listed below. The numerical values in the tables indicate the pendulum hardness in see according to DIN 53 157. The value v) means that the sample is measured directly after curing, while the value n) indicates the pendulum hardness after the cured sample has been immersed in a xylene bath for 15 minutes and then dried for one hour at room temperature

IMoI Fumaric acid lMol Phthalic anhydride 0.83 moles Tricydodecane dimethanol 1.25MoI Diglycol 33% Styrene
I 1 1 mole 11th
Fumaric acid 1 mole Phthalic anhydride 1.25MoI Tricydodecane dimethanol 0.85 moles Diglycol 33% Styrene

III

IV

1 mole Fumaric acid 1 mole Phthalic anhydride l.bbMol Tricydodecandimethano! 0.42 moles Diglycol 33% Styrene

! Mole Fumaric acid 4 moles Phthalic anhydride 1 mole Maleic acid 6.18 moles Tricydodecanedimeihanol 35% St \ roI

Tabel

polyester

Exposure time (min)

1 Fumaric acid 2 52 Styrene 2 π i 61 / j 18th 4th 80 ; Mole 13th Fumaric acid /1 22nd D. η 5 / j 21 \ η V 196 V 208 208 ι 217 1 mole - 208 V V 213 I a 48 16 194 10 201 : 98 155 201 0.42 moles 29 157 100 17th 15th 163 b 195 76 221 17th 149 227 203 229 1.66MoI 222 214 - 20th 223 Il a 179 139 210 7th 201 313 184 213 33% 188 205 43 9 192 b 180 143 2i3 Irradiation time (min) 20th 179 246 215 248 223 234 28 232 ill a 188 154 236 I. 210 247 178 247 154 219 198 b 214 169 232 ν η 167 230 200 232 202 241 205 IV a 231 161 200 ^ s Comparative Polyester B 254 b 225 187 7 - 230 Comparative polyester A 6 - Phthalic anhydride Phthalic anhydride - - 1 mole 2.08MoI propanediol-1,2 I mole 33% W. Tricydodecanedimethanoi Table II Diglycol polyester Styrofoam J V π A ^a ;; 10 4th b _ 18th 1 20th B ^a 12th 9 15th - ^B b - 20th 19th 44 27 7th 24

Claims (4)

Claims: I. Use of unsaturated polyester masses. Consisting of 1. an unsaturated polyester 2. a vinyl monomer which can be mixed with 1. miscibility 3. an activator system 4. Usual auxiliaries and additives for the production of coatings, which by curing with infrared rays with a wavelength from 1 to 5 μ can be obtained thereby characterized in that the diol component of the unsaturated polyester 1 to 40 to 100 mol percent from a diol of the general formula