DE2410856B2 - STABILIZATION OF UNSATATULATED POLYESTER RESINS - Google Patents

Description

'5

The invention relates to the stabilization of solutions of unsaturated polyesters in grafted polyesters Vinyl monomers which have good storage stability, especially the fastest gel times Hardening with cobalt compounds and / or tert. Amines and peroxides matter.

It belongs to the prior art that certain inhibitors, such as p-benzoquinone, 2,5-di-tert-butylbenzoquinone, Hydroquinone, tert-butylpyrocatechol, toluhydroquinone, such as those in German interpretation 1151932 or in German Offenlegungsschrift 19 27 320 are listed, unsaturated polyester resins are added to improve storage stability. Such additives cause However, when using effective quantities, there are usually considerable delays in the gel times, so that these resins do not meet today's demands for short curing times. Furthermore is known it. Use copper compounds in combination with the compounds mentioned in order to achieve the To increase storage stability, however, another disadvantage occurs, namely the deterioration of the Pot life of the peroxide-containing component, d. H. a deterioration in the peroxide resistance to what z. B. for the so-called two-head casting process in the processing of lacquer polyesters an essential one Disadvantage is.

In German interpretation 1151 932, a Process described in which to "not greening" set molding compounds, which usually take a long time Have gel times, additional accelerators from the group of phosphines and / or arsines and / or stibines can be added.

As can be seen from the examples in this publication, the addition of the additional accelerators mentioned results with the resins listed there, which are naturally slow-setting, a certain acceleration in the gel times. An essential idea of the above-mentioned interpretative document consists in a far-reaching one Keeping the gel times of the "non-greening" set and the mentioned additional accelerators constant provided cobalt-containing resins over long periods of time.

In the DT-OS (AS) 1769952 a procedure described for the curing of unsaturated polyester resins by means of electron beams, using as initiators (Accelerators) preferably phosphines, but also arsines and stibines are described. The addition of phosphines and arsines (the stibines appear only because of their belonging to the same group since they are not mentioned in any example) is intended to enable the radiation dose to be reduced during curing.

Surprisingly enough, it had now been found when using triarylstibines, especially triphenylantimony, the storage stability of those prepared in the usual way and without or in combination unsaturated pre-stabilized with small amounts of conventional stabilizers such as hydroquinone Polyester resins can be improved quite decisively without it becoming one There is a delay in the gel time, as occurs when the known stabilizers are added. This egg The effect is all the more surprising as the additional accelerators also mentioned in the German Auslegeschrift 1151 932 From the series of phosphines and arsines, these properties are not at all or only partially show to a limited extent. The corresponding compounds also have a stabilizing effect the other elements of the 5th main group of the periodic table, nitrogen and bismuth, do not appear.

The invention relates to the use of a triarylstibine which is optionally substituted on the aryl radical, optionally in the presence of minor amounts of a commonly used stabilizer, to stabilize solutions of unsaturated polyester resins in polymerizable vinyl monomers, in an amount of 0.001 to 1.0% by weight of the antimony compound, based on 100 g of a 66% strength polyester solution.

A particular advantage of the stabilizers used according to the invention is that - im In contrast to resins stabilized with copper compounds - no reduction in peroxide resistance entry.

Under unsaturated polyesters for the purposes of the invention polycondensation products from aß-unge saturated dicarboxylic acids with polyalcohols are to be understood, as they are, for. B. in Ulimann, Vol. 14, 1963, page 90 ff or in the book by J. Björksten et al., "Polyesters and their Application", Reinhold Publishing Corporation, New York 1956 and are generally available commercially. Some of the unsaturated carboxylic acids can be replaced by saturated, polybasic carboxylic acids. It is also possible to use unsaturated polyesters which contain γ-unsaturated ether residues, as described, for example, in German Auslegeschrift 1024654.

In addition to styrene, Λ-methylstyrene, esters and ethers of vinyl or aluminum alcohol, such as vinyl acetate, diallyl phthalate, and esters of acrylic or methacrylic acid can also be used as monomeric, ethylenically unsaturated polymerizable compounds.

The stabilizers according to the invention are advantageously added to the solution of the polyester in the monomers. Of course, these solutions can also contain pigments, dyes, fillers, glass or Textile fibers, thixotropic agents, UV absorbers, waxes, paraffin, smoothing and leveling agents and the like can be added.

The parts given in the following examples are parts by weight. The percentages of the Unless otherwise stated, additives refer to 66% solutions of the unsaturated polyester in the Monomers.

The gel time is determined by the time between hardener and gelation at a 25 g sample in a thermostat at 2O ⁰ C.

The shelf life is determined by storage at 70 ° C. up to the gelation point.

example 1

An unsaturated polyester with an acid number of 40 mg KOH / g, produced by condensing 90 parts maleic anhydride and 100 parts phthalic anhydride with 164 parts propylene glycol, is dissolved in 66% styrene and this solution is stabilized in a known manner with 0.015% toluhydroquinone. The polyester resin obtained in this way has a shelf life of 11-13 days at WC. The gelling time of this resin is 4 minutes and 20 seconds with the addition of 2% of a 1% cobalt naphthenate solution, based on the cobalt, and 3% of a 50% methyl ethyl ketone peroxide solution.

The addition of 0.2% triphenylantimony gives a shelf life ^{of 43 to 47 days at 70 °} C., while the gelation time under the aforementioned conditions is 4 minutes.

Example 2

on the other hand, post-stabilized with 0.2% triphenylantimony. The following table2 shows the influence of the conventional stabilizer and the stabilizer used according to the invention on storage capacity and gel times (Determination analogous to Example 1).

Table 2

20th

A mixture obtained by condensing 154 parts of fumaric acid and 100 parts of phthalic anhydride with 127 parts [. Propylene glycol and 44 parts of diethylene glycol with an acid number of 50 mg KOH / g of unsaturated polyester produced are dissolved in 66% strength in styrene and pre-stabilized with 0.002% toluohydroquinone. The shelf life of this resin is one day at 70 ⁰ C.

The following table 1 shows the storage life of the resin at 70 ° C. with various compounds of the elements of the 5th main group of the Periodic Table of the Elements. The information is given in days.

Toluohydroquinone

Triphenyl antimony

Gelierzeil

Shelf life at 70 ° C

(Seconds) (days)

0.002%
0.01%
0.002%

0.2%

135 1 250 9 120 15-16

Example 4

One obtained by condensing 100 parts of tetrahydrophthalic anhydride and 30 parts of maleic anhydride with 103 parts of diethylene glycol produced unsaturated Polyester with an acid number of 41 is dissolved in styrene in a ratio of 70 parts to 30 parts and is based on it on this solution, stabilized with 0.008% toluohydroquinone.

Mixture A

In 99.2 parts of the resin solution, 0.8 parts of dimethylaniline are added stirred in and the shelf life and gel time after adding 2% of a 50% benzoyl peroxide paste as determined in Example 1.

Table I.

additive Tri- Tri- Tri- Tri- Tri- lot phenyl phenyl phenyl phenyl phenyl in% amine phos arsine stibine until- phin well

5-6
11-12
! 5-16
17-18

40

45

Without triphenyl antimony
0.05% triphenyl antimony
0.2% triphenyl pntimony

200 s
205 s
196s

Mixture B

With a mixture of 99.15 parts of the resin solution, 0.05 parts of triphenylantimony are added and 0.8 parts of dimethylaniline the shelf life and, after adding 2% of a 50% benzoyl peroxide paste, determines the gel time.

Mixture C

A similar test is carried out on a mixture of 99.1 parts of resin and 0.1 part of triphenylantimony as well as the analogous additives as carried out in mixture B.

If 80 parts of the described in Example 2 are added, with 0.002% toluhydroquinone pre-stabilized resin with a further 20 parts of styrene to achieve a lower viscosity to come as required for various applications in processing Lacquer polyester is required and determines the gel time comparatively with the same resin that is still used 0.05% or 0.2% triphenylantimony were added for stabilization, as described in Example 1 Type, the following values result:

60

The peroxide resistance cannot be influenced by any of the mixtures stabilized with triphenyl antimony to be established.

Example 3

A polyester resin prepared as in Example 2, dissolved in styrene and pre-stabilized with 0.002% toluhydroquinone, is on the one hand with 0.008% toluhydroquinone, gel time

Shelf life
at 70 ⁰ C

Mixture A 3 min 6 hours Mixture B 3 min 45 hours Mixture C 3 min 6 days

'Example 5

An unsaturated polyester described in accordance with German Offenlegungsschrift 2104958 was prepared by condensing 306 parts of fumaric acid, 133 parts of tetrahydrophthalic anhydride, 368 parts of diethylene glycol and 113 parts of pentaerythritol triallyl ether and was dissolved in 65% strength in styrene in the presence of 0.3 parts of hydroquinone. Table 3 shows the gelling times and storage times of this resin without or with various amounts of triphenylantimony (the gelling times were determined by adding 0.1 part of dimethylaniline and 1 part of a 50% benzoyl peroxide paste in a thermostat at 20 ° C.).

Table 3

Triphenylantlmone oil time

Storage wedge at 70 ° C

0% 16 min 5 days 0.05% 16 min 14 days 0.1% 16 min 20 days 0.2% 16 min 20 days

Example 6

One by condensing 154 parts of fumaric acid and 100 parts of phthalic anhydride at 127 parts Propylene glycol and 44 parts of di-ethylene glycol with an acid number of 50 mg KOH / g of unsaturated produced Polyester is dissolved in 66% styrene and, based on this solution, stabilized with 0.1% triphenylantimony,

Can be stored at 70 ° C for 13 days carried out in Example 1) 2 minutes.

Claims (1)

Zl Claim: Use of a triarylstibine optionally substituted on the aryl radical, optionally in the presence minor amounts of a commonly used stabilizer, for stabilization of solutions of unsaturated polyester resins in polymerizable vinyl monomers, in one Amount from 0.001 to 1.0% by weight, based on 100 g of a 66% polyester solution.