DE2008984A1 - Linear copolyester for transparent injection mouldings - Google Patents

Abstract

Thermoplastic copolyester of 1 mol. terephthalic acid and 1 mol. mixture of bifunctional alcohols, with glass transition temp. >100 degrees C and specific viscosity 0.5 - 1.5, contains, per 10 mols. terephthalic acid, 1.5 - 5 mol dispiro (5.1.5.1)tetradecan-7,14-diol and 8.5 - 5 mol. 2 or 3 C aliphatic diol, (mixture), of which 20 mol % may be replaced by 1,4-dimethylolcyclohexane. This polyester gives hard, non-crystallizing, transparent mouldings, which can be used in wide temp. range. It is esp. useful for injection moulding, but can also be u sed to make fibres, films, coatings etc.

Description

Crystal clear, linear, thermoplastic mixed polyester with freezing areas over 1000C and process for their manufacture.

Linear polyesters made from aromatic dicarboxylic acids and divalent ones Alcohols such as polyethylene terephthalate or polyesters made from terephthalic acid and 1,4-dimethylol-cyclohoxane (DAS 1.222.205g Belgian patent 592.181) used to make fibers, threads and films. The by the great trend for crystallization caused haze of made from such polyesters Objects and the shrinkage effect associated with crystallization, that these polycondensates for processing into crystal-clear, amorphous moldings are not suitable.

Amorphous, crystal-clear moldings can be - provided that only small layer thicknesses are required - also made of polyethylene terephthalate Quench the polyester melt due to the low transition temperature However, they lose 2nd order, which is at 690C, at relatively low levels Temperatures their rigidity and their transparency, since they are already at the temperature of the boiling water begin to crystallize. Moldings or articles of daily use made of amorphous polyethylene terephthalate are for this reason only in the temperature range below the 2nd order transformation temperature with satisfactory Result applicable. To be more universal, i.e. in a broader temperature range usable, hard, non-crystallizing, giaskiare moldings is to be obtained it is therefore desirable to use polyester with a freezing range of over 100 ° C.

It is now inclined that mlt Dispiro (5.1.5.1) tetradecane-7,14-diol as Diol component polyester of terephthalic acid can be built up that this Requirements met.

The present invention therefore provides crystal clear, linear, thermoplastic mixed polyester with a freezing range above 100 ° C and a specific viscosity espez.

between 0.5 and 1.5 from 1 mole of terephthalic acid and 1 mole of a mixture bifunctional alcohols, which are characterized in that they, statistically seen, for every 10 moles of terephthalic acid 1.9 to 5 moles of dlapiro (5.1.5.1) tetradecane-7,14-diol and 8.5 to 5 moles of an aliphatic diol having 2 or 3 carbon atoms or a mixture contain such diols, optionally up to 20 mol% of the aliphatic diol content can be replaced by 1,4-dimethylolcyclohexane.

It was surprising that the secondary alcohol groups of Dispiro (5.1.5.1) tetradecane-7,14-diol, which are also prevented eterisoh, a complete with dimethyl terephthalate Enter into transesterification and thus be incorporated quantitatively into the mixed polyester.

The polyesters according to the invention have freezing temperatures, depending on their composition up to about 1500C and specific viscosity between 0.5 and 1.3, preferably 0.8 to 1.2.

To produce the mixed polyesters, diesters of terephthalic acid are used from, One uses the monohydric aliphatic alcohols with 1 to 4 carbon atoms or the C3 and C4 isoalcohols, for example methyl, ethyl, propyl, isopropyl or butyl ester. The methyl esters are preferably used.

Bifunctional alcohols are mixtures consisting of an aliphatic diol with 2-3 carbon atoms such as ethylene glycol, propylene glycol (1,3) or propylene glycol (1,2) or mixtures of such diols and the cyclic diol Dispiro (5.1.5.1 ) tetradecane-7,14-diol of the formula used. The latter can be obtained, for example, by hydrogenation of the dispiro (5.1.5.1) tetradecane-7,14-dione prepared from hexahydrobenzoyl chloride according to HM Walborsky and ER Buchmann (J.amer.Chem.Soc. I2, 6339 (1953)). If appropriate, it is also possible to replace some of the lower aliphatic diols with 1,4-dimethylolcyclohexane. However, its proportion in the finished polyester should not be more than 20 mol%, based on the total diol content. The Dispiro (5.1.5.1) tetradecane-7,14-diol is preferably used, but in a mixture with ethylene glycol.

The transesterification of the terephthalic acid ester with the diol mixture takes place advantageously with an excess of the lower-boiling diol component. The relationship of the monomers is chosen in a manner such that 1 mol of dicarboxylic acid ester is used 1 mole of the mixture of the aliphatic and the acyclic diol, which in the Polyester to be incorporated is present, and in addition another 1-2 moles of aliphatic diol are used. Through this way of working it is achieved that the transesterification both quantitatively and with a high reaction rate runs. Of course, after the transesterification has ended, the excess aliphatic Diol distilled off again.

The transesterification is carried out under nitrogen in the presence of 0.005-0.5% Catalyst carried out based on the total weight of the components used. 1 mol of dimethyl terephthalate with 1 mol of a mixture is preferred initially from 15-50 mol?, o Dispiro (5.1 .5.1) tetradecane-7,14-diol and 85-50 mol% of the aliphatic Diol reacted at 160 to 2200C until the elimination of alcohol is complete. Then it is cooled to about 1800C and after adding another 1-2 moles of the aliphatic Diols at 180 to 2400C brought the transesterification to an end. The transesterification requires generally a time of 5 to 12 hours, with the cleaved low-boiling point Distill off alcohol and excess aliphatic diol. Used as a catalyst one e.g.

Dibutyltin diacetate, or any of the other ones for this purpose common catalysts, e.g. manganese acetate, organic titanium compounds, etc.

The polycondensation of the transesterification product takes place in a known manner Way with the addition of a polycondensation catalyst such as Ges2, So203, GeHPO3 * (C4H9) 2Sn (CII3COO) 2. The latter compound is preferred. One heats it up initially 1-2 hours at 230 to 2600C - preferably 230 to 24000 - at approx. 12 Torr and then at 2400C for about 1 hour at 0.05 to 0.1 Torr. what to do with the Temperature gradually (within 2-3 hours) increased to 280 to 3000C and lightens at this temperature for about 2-3 hours. What is released is distilled here aliphatic diol ongoing. When the improper degree of polycondensation is reached the lteaction is canceled.

The amorphous, crystal-clear polyesters according to the invention are suitable preferred for the production of crystal clear injection molded articles, which are also in the field higher temperatures can be used. But they can also be turned into fibers Foils, coatings, etc. to process.

The method is explained in more detail by the following examples.

The freezing temperatures (TG) were determined by differential termal analysis at a heating rate of 2 ° C./min.

certainly.

Example 1 194 g (1 mole) dimethyl terephthalate, 44.8 g (0.2 mole) Dispiro (5.1.5.1) tetradecane-7,14-diol and 49.6 g (0.8 moles) of ethylene glycol were added after adding 40 mg of dibutyltin diacetate as a transesterification catalyst in an inert gas atmosphere (nitrogen) gradually Heated to 2200C. After cooling to 1800C, a further 93.0 g of ethylene glycol were added. It was then kept at this temperature for 2 hours and then slowly heated to 2400C. This temperature was maintained until the end of the distillation of methanol and excess ethylene glycol retained. Then the transesterification product became after adding 40 mg of dibutyltin diacetate as a polycondensation catalyst, 1 hour at a vacuum of 12 mm Hg and 1 hour at a vacuum of 0.1 torr at 240 ° C touched.

It was then gradually heated to 280 ° C and 3 hours at stirred at this temperature. The released ethylene glycol distilled off. A crystal-clear, amorphous polyester with the specific viscosity was obtained tspec a 0.92 and a freezing range of 105-112 ° C.

Example 2 Following the procedure described in Example 1, 194 g (1 mol) of dimethyltorephthalate with a mixture of 56 g (0.25 mol) of Dispiro (5.1.5.1) tetradecane-7,14-diol and 46.3 grams (0.75 moles) of ethylene glycol, plus an additional 93 grams of ethylene glycol interesterified and then polycondensed.

The result was an amorphous, crystal-clear polyester with a specific Viscosity espec. t 0.53. The freezing range of this mixed polyester was 118-127 0C.

Example 3 Following the procedure given in Example 1, 194 g (1 mol) of dimethyl terephthalate with a mixture of 89.6 g (0.4 mol) of Dispiro (5.1.5.1) tetradecane-7,14-diol and 37.2 e (0.6 moles) of ethylene glycol, plus an additional 93.0 g of ethylene glycol interesterified and then polycondensed.

The result was an amorphous, crystal-clear polyester with a specific Viscosity espec. 3 0.90. The freezing range of this mixed polyester was 130-140 ° C.

Example 4 As described in Example 1, the reaction was carried out of 194 g (1 mol) of dimethyl terephthalate with a mixture of 44.8 g (0.2 mol) of Dlspiro (5.1.5.1) tetradeoan-7,14-diol, 28.8 g (0.2 mol) of 1,4-dimothylolcyclohexane and 37.2 g (0.6 mol) of ethylene glycol below Add another 93 g of ethylene glycol, a crystal-clear, amorphous synthetic polyester the specific viscosity <spes. 1 0.80 with a freezing range of 105-115 ° C obtain.

Claims (4)

Patent claims: 1.) Crystal clear, linear, thermoplastic mixed polyester with a Freezing range above 1000C and a specific viscosity espez. between 0.5 and 1.5 from 1 mole of terephthalic acid and 1 mole of a mixture of bifunctional Alcohols, characterized in that, from a statistical point of view, they are in each case 10 moles Terephthalic acid, 1.5 to 5 moles Dispiro (5.1 .5.1) tetradecane-7,14-diol and 8.5 to 5 moles of an aliphatic diol with 2 or 3 carbon atoms or a mixture of these Contain diols, optionally up to 20 mol% of the aliphatic diol content can be replaced by 1, 4-dimethylolcyclohexane. 2.) Process for the production of crystal clear, linear, thermoplastic: plastic Mixed polyester with a freezing range above 100 ° C, through transesterification of dicarboxylic acid diesters with diols and subsequent polycondensation in the presence of catalysts, thereby characterized in that dialkyl terephthalate is made with a mixture from Dispiro (5.1 .5.1) tetradecane-7,14-diol and one or more aliphatic Diols with 2 or 3 carbon atoms are transesterified in a known manner at 160 to 2400C, until the elimination of alcohol has ended, and then the transesterification products obtained in a known manner at 230 to 300 ° C to a specific viscosity tspec. polycondensed from 0.5 to 1.5. 3.) The method according to claim 2, characterized in that one Partial amount of the aliphatic diols replaced by 1,4-dimethylolcyclohexane, with the amount of which is such that it is contained in the polycondensate obtained as the end product at most 20 mol%, based on the total diol content, are included. 4.) Process according to claim 2, characterized in that 1 mol Terephthalic acid dimethyl ester with 1 mol of a mixture consisting of 15 to 50 mol% Dispiro (5.1.5.1) tetradecane-7,14-diol and 85 to 50 mol% ethylene glycol as long transesterified in a known manner at 160-220 ° C until the alcohol cleavage has ended, after cooling to 1800C, a further 1 to 2 moles of ethylene glycol are added, then the transesterification leads to completion at 180 to 2400C, and finally the transesterification products obtained polycondensed at 230-300 ° C in a known manner.