DE1098712B - Increasing the storage and color stability of peroxide catalyst-free polyester resin compounds - Google Patents

Description

Increase the storage and color stability of peroxide catalyst-free Polyester Resin Compounds The type of unsaturated polyester referred to herein can be obtained by esterifying an α, -unsaturated carboxylic acid with a glycol represent. Part of the unsaturated carboxylic acid can be replaced by a saturated dibasic Carboxylic acid and / or a small amount of a monobasic carboxylic acid are replaced, and a small part of the glycol can be polyvalent against pentaerythritol or another Alcohol and / or a monohydric alcohol can be exchanged.

The invention relates to unsaturated polyesters such as polyethylene glycol terephthalate, which form essentially linear fibers, and also non-normal types of alkyd resins, which are modified with substantial amounts of fatty oils and / or oleic fatty acids. The polyester compositions usually contain a polymerizable monomer and are primarily for the production of glass fiber laminates or as cast or Compression mixtures intended for the production of shaped articles, wherein the mass cured will.

It is known that linear fiber-forming polyesters of the polyethylene glycol terephthalate type can be produced in the presence of a small amount of phosphite.

In this process, the phosphite is used right at the start or in one Intermediate stage of polycondensation added to the polyester starting materials (See, for example, British patents 588833 and 588 534) on page 3 of the The latter patent is noted on line 122 that the phosphite is not pure mechanically mixed with the linear polymer, if the desired Has set the degree of condensation, but the phosphate must with the terminal Groups of the condensate can react.

The object of the invention is the storage and color stability of Peroxide catalyst-free polyester resin compositions based on unsaturated polyester essentially from unsaturated α,-unsaturated dicarboxylic acids and glycols as well as to increase polymerizable monomeric compounds. According to the invention this goal is achieved by adding phosphorous acid to the polyester resin compositions andlor adding phosphorous acid esters in dissolved form. According to a preferred embodiment the phosphorous acid or its ester in amounts of at least 0.001 percent by weight, based on the phosphorous acid and the resin composition.

The invention also increases color stability Storage achieved in the presence of air or iron. Furthermore, the storage stability increases, especially what the resistance to thickening or viscosity increase or gelling if the masses are stored at tropical temperatures, without hardening in the slightest slower than normal at elevated temperatures Resins of this type. Another advantage is that the invention with phosphorous Acid or phosphorous acid esters added to resin compounds even when hardened with catalyst systems, which contain peroxides and cobalt salts remain colorless and that no extension either the "pot life" of the catalyzed systems can be determined.

The storage stability can be increased by adding one of the usual inhibitors used, generally a phenolic compound such as hydroquinone or tert. Butyl catechol. The phosphorous acid, the phosphorous acid ester or a mixture of phosphorous acid esters can be used before, during or after admixing of the polymerizable monomer are incorporated into the unsaturated polyester resin. In contrast to the older method cited above, the addition can also be made after the condensation of the polyester has been completed. When hardening the mass an additional polymerization reaction occurs between the polyester and the polymerizable Monomers.

Various phosphorous acid esters can be used so far they are soluble in the polyester mass. Examples are tri-p-cresyl phosphite, triphenyl phosphite, Diisopropyl phosphite, dioctyl phosphite, tricyclohexyl phosphite, noctyl phosphite, tricetyl phosphite, Trioleyl phosphite, tristearyl phosphite, triethyl thiophosphite, triamyl thiophosphite, Triphenylthiophosphite, trichloro ethyl phosphite, trichloro-tert-butyl phosphite and trip-chlorophenyl phosphite.

Polyesters of maleic acid and fumaric acid are preferred. Examples of saturated acids which can also be used if desired Adipic acid, sebacic acid, phthalic acid, isophthalic acid and terephthalic acid as well substituted acids such as tetrachlorophthalic acid.

The monomers which can be polymerized on are styrene or a substituted one Styrene, e.g. B. methylstyrene, is preferably used. Other monomers such as methyl methacrylate and diallyl phthalate, but can be used instead of or as an additive.

In the following the invention is illustrated by way of example. All parts and percentages relate to weight.

Examples 1 to 10 An unsaturated polyester resin (P) has been known in US Pat Way prepared by adding a mixture of 2.9 parts of propylene glycol, 1.7 parts of maleic anhydride and 2.6 parts of phthalic anhydride heated to 200 "C in an inert atmosphere became. When the acid value of the resin reached 50, the resin was poured out and leave to cool. The polyester P became two solutions with different Hydrochmon content is made by adding 200 parts of polyester to 100 parts of cold styrene one time 0.024 part, the other time only 0.012 part of hydroquinone contained.

The two polyester resin solutions became two series of solutions prepared by triphenyl phosphite according to the invention in each case in the ratio 0.3, 0.2, 0.1 and 0.05 01o (based on the solution) was added.

As a control, no phosphite was added to one of the ten samples.

The following investigations were carried out: 1. Color determination of the resin in Hazen units (corresponds to the APHA color units of the American Public Health Association [cf. "The Standard Methods for the Examination of Water and Sewage ", Ainerican Public Health Association, 9th edition, p. 9]) after manufacture of the solutions.

2. Color determination of the resin after 39 days of storage in a glass vessel at room temperature (about 200 G). The vessel was so full. that a narrow There was still air space and contained a piece of mild steel sheet.

3. Storage of resin solution, which is prepared as above under 2 and was filled in flasks, in an oven at 55 "C and checked daily for gelation for a total of 39 days.

4. Determination of the gelation time of the resin at 800 ° C. after 39 days Storage at room temperature.

The method of the Society of the Plastics Industry of the UNITED STATES. (Proceeding of the 6th Annual Meeting of the Technical Section of the Reinforced Plastics Division) applied after 1.0 01o of a paste of equal parts of benzoyl peroxide and dimethyl phthalate and so much cobalt naphthenate solution were added that a concentration of 0.004% cobalt, calculated as metal, was reached.

5. Visual examination of the color of the casting produced in the gelation test (4). Gel time Tri-staining in Hazen units. Storage stability at 800C Sample staining m at be 550C after a Sample hydroquinone phenyl (period until storage of color of No phosphite content after 39 days of occurrence of the casting after 39 days Making storage of gelation) at ordinary temperature ° lo o / 0 (1) (2) (3) (4) (5) 1 0.008 0.3 70 to 85 70 to 85 over 100 days 191/2 minutes as clear as water 2 0.008 0.2 70 to 85 70 to 85 over 100 days 191/2 minutes as clear as water 3 0.008 0.1 70 to 85 70 to 85 25 days 19 minutes very weak pink 4 0.008 0.05 70 to 85 70 to 85 17 days 19½ minutes very weak pink 5 0.008 - 70 to 85 125 to 150 7 days 19½ minutes clearly orange 6 0.004 0.3 70 to 85 70 to 85 over 100 days 12 every 2 minutes as 1 7 0.004 0.2 70 to 85 70 to 85 over 44 days 121/2 minutes as 1 8 0.004 0.1 70 to 85 70 to 85 8 days 111/2 minutes like 3 9 0.004 0.05 70 to 85 70 to 85 8 days III / 2 minutes as in 3 10 0.004 -: 70 to 85 1 100 to 125 8 days 13 minutes like 5 The above results show a) the excellent color fastness of triphenyl phosphite-containing resins on storage (columns 1 and 2), b) a very strong increase in storage stability at 550 ° C. through the addition of 0.2 OO or more triphenyl phosphite (column 3) without noticeable Reduced reactivity in the presence of a peroxide catalyst (column 4), c) color improvement of the cured resin (column 5).

Examples 11 to 15 An unsaturated polyester resin has been known in US Pat Way prepared by placing in an inert atmosphere a mixture of 602 parts Propylene glycol, 462 parts of maleic anhydride and 351 parts of phthalic anhydride was heated to 190 to 200 "C until the resin had an acid value of 30 to 40. 0.17 part of hydroquinone was added and the resin was poured into dishes to cool. Then it was crushed and dissolved in half the amount of styrene. With each of the Examples 11 to 15 used 100 parts of this mixture and according to the invention with the amounts of different substances listed in the table below Phosphorous acid ester added. These additions have been sized so that they all contained the same amount by weight of phosphorous acid ester as the 0.2 parts of triphenyl phosphite.

The color was determined in Hazen units at the beginning and after storage for one month in the presence of iron. While the sample containing no phosphite (No. 15) spoiled, the others showed no or little change. The gel time at 80 "C was only slightly affected. stability Addition of Phb.t - Hazen units n; Gel time at 550C Example Addition of phosphorous acid esters at 800 C after a month initially after 1 month of storage 11 0.107 parts diisopropyl phosphite 40 40 16 minutes 10 days 12 0.197 parts dioctyl phosphite 30 40 16 minutes 10 days 13 0.27 parts trioctyl phosphite 30 30 15 minutes 7 days 14 0.20 parts triphenyl phosphite 30 40 15 minutes over 28 days 15 - 30 60 to 70 16 minutes 8 days Unless otherwise stated, the tests were carried out as in Examples 1 to 10.

Example 16 Samples of a polyester resin composition similar to that used in Examples 1 through 5 were mixed with varying amounts of phosphorous acid by adding the acid to the resin samples and heating the whole to about 80 "C until the acid melted and became ingestible. Each sample was divided into two parts and each part was provided with a piece of mild steel plate. One sample was kept at 55 "C to test the storage stability as in Examples 1 to 10 and the other was stored for 1 year at room temperature, after which the color was determined . Sample Phosphorous stability staining after 1 year red acid at 55 ° C at room temperature A 0.1 0 / o 62 days 70 Hazen units B 0.05% for 39 days, 60 to 70 Hazen units C 0.02 0 / o 38 days 70 Hazen units D - 22 days 200 Hazen units Example 17 Various amounts of triphenyl phosphite were stirred into samples of a polyester blend similar to the blend used in Examples 11-15 immediately after preparation. The mixtures were then stored in mild steel drums of 13.6 l capacity at room temperature and examined at certain time intervals. Triphenyl staining in Hazen inclusions. Geiierungszeit Sample phosphite after after at 800 C after at 80 ° C after pot life at 250 C after additional at the beginning of 5 months 12 months of 12 days of storage 12 months of storage (i) - 60 to 70 100 1,225 19½ minutes 24 minutes (ii) 0.1 60 to 70 70 70 16 minutes 115 minutes (iii) 0.2 60 to 70 70 70 17 minutes 24 hours (iv) 0.3 60 to 70 70 70 18½ minutes over 24 hours The tests were carried out as in Examples 1 to 10. The "pot life" is the time the resin needs to gel at 25 ° C after it has been mixed with 2% of a solution of 60 parts of methyl ethyl ketone peroxide in 40 parts of dimethyl phthalate and 1% of cobalt in the form of cobalt naphthenate.

The invention was also tested in that phosphoric acid esters have been incorporated into various other commercially available resins. It resulted similar results as above. Instead of styrene as a polymerizable monomer diallyl phthalate, methyl methacrylate and other monomers can be used equally well will. The following example shows in particular the use of methyl methacrylate.

Example 18 An unsaturated polyester was prepared in a conventional manner, adding 1166 parts of propylene glycol, 1372 parts of phthalic anhydride and 548 parts of fumaric acid together in an inert atmosphere for 3 hours at 150 to 160 ° C and then up 195 to 200 ° C were heated until the acid value dropped to 35. Then it was allowed to cool and mixed with 1320 parts of styrene and 300 parts of methyl methacrylate.

Samples of this mixture were taken and added 0.01% triphenyl phosphite alone, with 0.01% hydroquinone alone, which is one of the best-known inhibitors is, and mixed with both together. The stability of all samples including an additive-free control sample at 55 "C was determined as follows: 18 A control no additives .... 1 day 18 B A + 0.01 0 / o triphenyl phosphite 1 day 18 C A + 0.01 0 / o hydroquinone 7 days 18 D C + 0.01 0 / o triphenyl phosphite and 0.01% hydroquinone 12 days The results show that less than 0.02 weight percent triphenyl phosphite effectively increase the stability of mixtures stored at high temperature, which contain an inhibitor. As far as color stability is concerned, even lower Amounts of phosphites, especially triphenyl phosphite, and / or phosphorous acid be used. It has been found that a concentration of 0.005 percent by weight in the presence of iron the color fastness improves somewhat and that even more as little as 0.001 weight percent phosphorous acid to be effective appears.

PATENT CLAIMS 1. Use of phosphorous acid and / or phosphorous acid esters in dissolved form to increase the storage and color stability of peroxide catalyst-free Polyester resin compositions based on unsaturated polyester, essentially composed of unsaturated a, B-unsaturated dicarboxylic acids and glycols and monomeric monomers which can be polymerized onto them Links.

2. Use of triphenyl phosphite according to Claim 1.

Claims (1)

3. Use of phosphorous acid or its ester in amounts of at least 0.001 percent by weight, based on the phosphorous acid and the resin composition, according to claims 1 and 2. 4. Use of phosphorous acid or its ester with addition Common inhibitors according to Claims 1 to 3. References considered: U.S. Patents No. 2,632 751, 2,543,635, 2,646,416; Modern Plastics, 32 (February 1955), 131-138 and 233.