DE2260132B2 - USE OF UNSATURATED POLYESTER MATERIALS FOR THE PRODUCTION OF COATINGS - Google Patents

Description

It is known that unsaturated polyester shark: more suitable as molding and coating compounds after addition Initiators and accelerators for curing at room temperature, for coating wood, glass and Stone slabs can be used. The polyester compositions can also after the addition of fillers can be used as fillers. A significant reduction in curing times before stacking and sandability of the coated surfaces is achieved through the use of ionizing rays possible.

The DT-AS 20 58 294, DT-OS 16 21. 900, the OE-PS 2 95 858 and the DL-PS 78 374 work in principle assumes that the coatings are cured by radikalbilden.de or ionizing, high-energy radiation will.

The unsaturated polyester resins hardened with UV rays (DT-OS 20 54 832) have the disadvantage that light-colored pigmented varnishes can yellow, for which the presence of the UV sensitizer is held responsible. Another disadvantage is that fillers containing fillers, cure incompletely, especially with thicker layers than 100 μ, so that during use Defects such as cracking or peeling phenomena occur.

The US-PS 35 33 999 describes UPE resins that in addition to maleic acid, the acid component should contain a partially hydrogenated aromatic acid. Another condition, however, is the mandatory use of neopentyl glycol in the diol component. It is also stated that the hardening times the greater the proportion of partially hydrogenated aromatic acids lengthen and that at the same time the hardness of the end product decreases.

The GB-PS writes analogously to US-PS 35 33 999 br

12 55 070 has a similar acid component, but is also used for the alcohol component a certain composition is required. It is noticeable that the UPE resins described can be cured with ionizing radiation, but the more obvious option curing by IR rays is not mentioned.

It is known that the disadvantages described

ίο avoided by curing by infrared rays (DT-OS 20 29 657). This type of hardening is especially useful for clear coats, pigmented ones Paints and highly filled fillers are suitable. The drying times are longer, however.

These longer irradiation times cause the substrate to heat up to an undesired 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 incompletely. As a result, the films swell or even swell on treatment with xylene to be resolved.

The object of the invention was by using

of polyesters of suitable composition to produce coatings with good properties, which can be obtained by curing by infrared rays, and being those listed above Disadvantages of the prior art are avoided. This task was accomplished through the use of unsaturated polyester masses dissolved, the

1. an unsaturated polyester, its acid component

A. to 20 to 85 mol percent of fumaric acid or maleic acid and

B. 80 to 15 mol percent of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid where at least 15 mole percent of the total acid component is tetrahydrophthalic acid and / or their anhydrides,

2. a vinyl monomer which is copolymerizable with 1.,

3. an activator system,

4. Usual auxiliaries and additives

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

In addition to the fumaric acid, maleic acid and tetrahydrophthalic acid required in the acid component and / or their anhydrides come as aliphatic dicarboxylic acids, succinic acid, adipic acid, as cycloaliphatic Dicarboxylic acids hexahydrophthalic acid and, as aromatic acids, phthalic acid or anhydride, Isophthalic acid, trimellitic acid, hexachloroendomethylene tetrahydrophthalic acid, Tetrabromic or tetrachlorophthalic acid in question.

In any case, fumaric or maleic acid and tetrahydrophthalic acid are necessary according to the invention in the specified quantities. A preferred proportion of fumaric or maleic acid is 40 to 85 mole percent. A preferred lower limit for tetrahydrophthalic acid is 30 mole percent. in the Particularly suitable are those polyesters which contain only fumaric or fumaric acid in the acid component.

Contain maleic acid on the one hand and tetrahydrophthalic acid on the other. The following specified Acids can partially replace the acids that are absolutely necessary according to the invention for the production to make the polyester more economical.

The fumaric or maleic acid used causes good crosslinking, which increases with the amount; on the other hand, a good surface hardness is achieved by the tetrahydrophthalic acid, which also increases with increasing amounts.

For the unsaturated polyesters according to the invention, ethylene glycol (l, 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), furthermore neopentylglycol ah branched chain, ether grape-free diols; unbranched-chain diols containing ether groups are suitable all diethylene, also triethylene or tetraethylene glycol; as branched chain containing ether groups, especially dipropylene glycol or tripropylene glycol, used.

Suitable unsaturated, copolymerizable vinyl monomers are the usual ones, such as styrene, substituted styrenes, such as tert-butylstyrene or methylstyrene; also mixtures of the latter with styrene. Other ethylenically unsaturated monomers that can be used in combination with styrene in amounts of less than 50 percent by weight, based on the monomer _{mixture, are lower (Ci-C 4} ) -alkyl esters of acrylic acid or methacrylic acid and halogenated styrenes such as chlorostyrene and dichlorostyrene , 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 around 20 to 50, in particular 25 to 40. Accordingly, the molecular weight, which is not critical for the Invention is between 5500 and 800, preferably between 3000 and 10000, in particular at 2500 and 1500.

Catalysts which form free radicals such as diacyl peroxides, ζ. Β. 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 in quantities from 0.1 to 3 percent by weight can be used. The peroxydicarbonates are particularly suitable especially those with 3 to 6 carbon atoms in the alkyl radical, such as, for example, diisopropyl peroxydicarbonate, di-tert-butyl peroxydicarbonate or dicyclohexyl peroxydicarbonate. Likewise, the addition of hardening accelerators such as tertiary, aromatic amines or cobalt salts are possible.

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 Be light stabilizers.

The Pulyester masses according to the invention are characterized by a number of good properties: In addition to good general properties, IR curing enables quick drying in a short time and good curing of the coatings is achieved. The drying time depends essentially on the one used Amount of acids according to the invention from.

When hardening, the drying times depend on the

Proportion of the acid according to the invention in the polyester from:

When using 0.5 percent by weight of peroxide, based on the polyester molding compound, drying times of about 4 minutes can be achieved with an acid content of 17 mol percent of tetrahydrophthalic acid, and drying times of about 3 minutes with a content of about 33 mol percent.
As the explanations show, the polyester compositions according to the invention - even if they are filled - can be processed quickly and easily with the aid of IR rays. The curing is very good, so that coatings produced according to the invention - even in toluene - have good solvent resistance.

In contrast, correspondingly hardened polyester coating compounds show their polyester only fumaric acid or tetrahydrophthalic acid as the acid component contain, insufficient solvent resistance.

With the help of the invention it is achieved that the processor already existing, inexpensive IR systems can be used without the need for expensive equipment for generating ionizing radiation must be procured, as the state of the art suggests. Another advantage is the fact that Inexpensive starting materials can be used for the production of the polyester.

Examples

A polyester resin was applied to glass plates (17 cm × 7.5 cm) with a film applicator in one layer applied by 100 μ, predried for one hour at room temperature and then with a Hardened IR emitter type H 8 from Heraeus. The distance between the radiator and the paint film was 45 cm. With the polyesters I to VIII listed below (Table 1), those obtained in the tables were obtained Results achieved. The numerical values indicate the pendulum hardness in see according to DIN 53 157. At attempt a the sample with 0.5 percent by weight isopropyl peroxide carbonate, in test b with 0.5 percent by weight Isopropyl peroxide carbonate and 1 percent by weight of a cobalt octoate solution, the cobalt content of which is 1% is cured.

Tables 3 to 5 show the extent to which polyesters I to VIII produce solvent-resistant coatings. The values under a and b have the meaning already given above. The value ν means that the sample is measured directly after curing, while the value η indicates the pendulum hardness after the cured sample has been immersed in a xylene bath for 15 minutes (Tables 3 and 4) and then dried for 1 hour at room temperature. The polyester samples from Tables 4 and 5 were cured according to test arrangement b.

Table 1

polyester

Irradiation time (min.) FS *) PS *)

PPE *)

THPS *)

PD *)

I (comparison) 1.0 II (comparison) 2.0 III 2.0 IV 2.0 V 1.0 VI 1.0 VII 1.0 VIII (comparison) -

0.9 0.5

Styrene,%

- 2.1 33 0.1 3.06 35 0.5 3.06 35 1.0 3.03 3f 1.0 2.1 33 1.85 2.95 33 3.0 4.04 35 1.0 1.03 33

*) FS = fumaric acid, PS = phthalic acid, PSA = phthalic anhydride, THPS = tetrahydrophthalic acid, PD = propanediol- (1,2).

Table 2

polyester

Exposure time (min.)

I. a
b 156
196 177
203 180
202 II a
b 120
201 132
222 146
244 III a
b 106
212 104
230 113
246 IV a
b 51
191 56
208 62
217 V a
b 137
183 144
201 152
212 VI a
b 64
215 75
218 89
225 VII a
b 83
169 91
183 94
193 VIII a
b 10
124 16
141 27
174

Table 3

Polyester exposure time (min.)

2
ν η

I. 191 - 196 - 203 - 202 - ΪΙ 142 - 201 - 222 - 244 - III 164 17th 212 26th 230 167 246 201 IV 157 21 191 167 208 197 217 216 V 173 149 183 160 201 197 212 208 VI 200 183 215 212 218 219 225 214 VII 165 100 169 169 183 186 193 192 VIII 106 124 141 174 i

Table 4

polyester Exposure time (min.) 1 V π 2 V η 3 V η 4th 5 ν π 130 156 ν η 180 172 - 191 196 177 - 202 - I. a - 95 120 --- 203 - 146 - - · b - - 142 - 201 - - '' ■ '■■' ^: λιι ■■■ -— ■: 244 - II a 107 25th 128 30th 137 30th 222 - 152 45 b 143 15th 173 149 183 160 144 40 212 203 V a - - - - 201 197 - - b 60 106 124 - - 174 VIII a 141 - b

Table 5 Exposure time ν π 96 (Min.) 3 ν π 4th ν π 5 ν η solvent polyester 2 161 150 173 164 183 183 192 191 161 164 173 169 183 178 192 191 161 173 175 183 176 192 190 Xylene VII 98 103 114 - 133 - 163 - Xylene: white spirit (1: 3) 98 100 114 118 133 123 163 126 White spirit 98 114 115 133 120 163 124 Xylene VIII Xylene: white spirit (1: 1) White spirit

A line in the tables means that the surface is sticky and therefore no pendulum hardness can be measured.

•! Ste- - ·

Claims (4)

Claim: Use of unsaturated polyester compositions that 1 · an unsaturated polyester, its acid component the end A. to 20 to 85 mol percent of fumaric acid or maleic acid and B. 80 to 15 mole percent from an aliphatic, cycloaliphatic or aromatic dicarboxylic acid, with at least 15 mole percent of the total acid component tetrahydrophthalic acid and / or its Anhydrides, 2. a vinyl monomer copolymerizable with 1. 3. an activator system, 4. Usual auxiliaries and additives contain, for the production of coatings, which by curing with infrared rays with a Wavelength of 1 to 5 μ can be obtained.