DE1645399C - Process for the production of linea ren polyesters - Google Patents

Description

Linear polyesters derived from glycols and diacids that can be drawn into fibers are known. The polyesters obtained from terephthalic acid and a glycol of the general formula HO (CH ₂ J _n OH. In which η is an integer between 2 and 10, and in particular polyethylene terephthalate) have proven to be of particular interest.

This latter is reduced by polycondensation of bis-U-hydroxyethyl) terephthalate Preserved pressure at elevated temperature. This monomer in turn is generally through Transesterification of ethylene glycol with dimethyl terephthalate obtained.

It can also be obtained by directly adding terephthalic acid with ethylene glycol or /-.thyle: oxyd implements.

In all cases it is necessary for the reactions to proceed in a relatively short time, in the presence of catalysts to work.

It μι known to use metals or their organic or inorganic derivatives as catalysts both for the transesterification and for the polycondensation.

For example, antimony oxide is most often used to catalyze the polycondensation reaction, but own this has the disadvantage of being in the form of a powder that is present in the reaction mixture is quite sparingly soluble and it must be used in relatively large amounts.

The invention relates to a method of manufacture of polyesters by polycondensation of bis (oi-hydroxyalkyl) terephthalates or their oligomers in the presence of a polycondensation catalyst containing a nitrogen atom. The procedure is characterized in that triethanolamine is used as the polycondensation catalyst.

It is already there to speed up this polycondensation reaction the use of a complex of triethanolamine with bismuth has become known, however the polymers obtained are a little colored.

It is also known as a transesterification catalyst to use tertiary amines such as trimethylamine, N-ethylmorpholine or N-cyclohexyl diethylamine, but these amines must be removed by evaporation prior to the polycondensation in order to achieve a to obtain practically undyed polymer.

Furthermore, these amines should preferably not have any reactive groups, such as, for example, in particular Hydroxyl groups. It was therefore surprising that the triethanolamine when used as a polycondensation catalyst gives good results and leads to uncolored polymers like the Examples show.

The melting point of the triethanolamine is about 20 to 21 ° C, and the triethanolamine is according to the invention preferably used in liquid form.

The triethanolamine is with the reaction, 0 semi-completely miscible, and the necessary to achieve a sufficient catalytic effect Menee is very small, on the order of 10 to 500 parts by weight per million based on dimethyl terephthalate, and preferably from 50 to

“250 files per million.

In those cases in which the bis (r.) - hydroxyalkylj-terephthalate by Transesterificationz \> i; = heneinem Obtained terephthalic acid diester and a glycol are, the poly-used according to the invention

condensation catalyst added to the reaction components when the transesterification is complete. in general, a conventional esterification catalyst such as calcium acetate is also used. Manganese (II) acetate or zinc acetate. Man work-

part at the usual temperature of the polycondensation, preferably at 270 to 290 "C.

The following examples illustrate the invention.
In the examples and comparative experiments compiled in Table I, the polycon-

densation carried out in the following way:

You first run the in a 10-1 glass flask Transesterification between 3298 g (17MoI) dimethyl terephthalate and 2635 g (42.5 mol) of ethylene glycol in the presence of a transesterification catalyst.

After the methanol and the excess ethylene glycol have been distilled off, the reaction mass is transferred in a stainless steel autoclave with a capacity of 7.5 liters, which is equipped with a System for moving is equipped. Then you bet

the reaction components which are at a temperature of about 23O ⁰ C, the polycondensation catalyst in liquid form or in suspension in glycol in the case of antimony oxide and 0.5 weight percent, based on the polymer, of titanium

oxide. suspended in ethylene glycol too. The reaction mass is then heated with agitation at 250 ° C. at atmospheric pressure, ethylene glycol being continuously distilled off. It is then heated from 2: "0 C to the temperature T selected for the polycondensation, the pressure in the autoclave being gradually reduced to 2.5 mm Hg continues to reduce the pressure to 0.2 mm Hg.

the reaction mass is kept at temperature T at all times. As can be seen from Table I, the duration of this last phase varies with the type and amount of catalysts. In particular, the comparison of Examples 1 and 2 with Comparative Experiments A and B shows the advantages that triethanolamine offers over antimony oxide: the amount used is much lower, and the polycondensation phase is much faster. In the two cases, the number of terminal groups COOH and the softening point are very similar. The triethanolamine thus does not deteriorate the polymer and its catalytic activity is very rapid and substantial.

NUch Λ uch C L "mesterung>, ka'.al \ aior 'Ii Pole \ condens> ation> catalyst PoK condensations ¹
phase ¹ pp length of time Properties of the
! EG COOH ' Pr ilymeren Art crowd I.
I. Art : Quantity ¹ ) ;! C. 2S5 1 sid. 2 () VZ-) ) EP C) Example I. Comparative experiment B Manganilli acetate Ii) p t Tmihano lamb '5Ί 2X5 1 hour-H) 0.6 (i 30th I 261 \ comparison Example 3 likewise i KIN Sb-O, 2.x 5 1 Sld. 30 0.6h 25th ! 261 Example 2 Comparison> ver C.ilciumacet.it i ISii I. Triethano iamin 34i; ^ 7 ^ 1 hour 45 0.66 2S the same ISO I. Sb-O, H) 275 I sid. 33 0.6h 33 ZinkacelLit J 54 Triä'.hano :.:! m: n I sir ".22 0.66 33 desiil. 54 Sb, O, 0.66 262 340 262 IO 261.5 170 261.5

¹ I parts by weight per million of metal! IMn. Sb. Ca. Zn) or at Tnäthar-.ilamin. based on dimethyl terephthalate.
"'^ 2 - viscosity number, determined at 25 C with a solution with 1 percent by weight per volume of polymer! In o-chlorophenol.
I EG COOH = number of terminal COOH groups per ton of polymer.

Ί EP = softening point, as measured by penetrometry Ida Besiimmunasprinzip is OB e d c ar and E. E 11 he v. J. Chem. Soc. 2633-263S [1952], given I.

In the examples 4 to 7 compiled in table II, the polycondensation was carried out after the The same procedure as in Examples 1 to 3. but in an autoclave with a capacity of 50 l in the presence of 0.5 percent by weight based on polymer, on titanium oxide in suspension in glycol and on phosphoric acid at 285'C accomplished.

From Table II it can be seen that the polar con

Densation duration and the properties of the polymer are little dependent on the amount of triethanolamine introduced vary. In addition, the presence of phosphorous acid affects the properties (Viscosity number, terminal groups COOH. Softening point) of the polymer not noticeable, but the duration of the polycondensation is somewhat increased.

Tables

at Umesterjngska'.aKsator crowd game 180 Art ISO 4th Calcium acetate 180 5 the same 180 6th the same 7th the same

Poiykondensationskaiaiysator Type ί Quantity ¹ )

Triethanolamine desgl. Desgl.

¹ I. ^:) . ³ ). ^J ) have the same meanings as in Table I. ⁵ ) Percentage by weight, based on dimethyl terephthalate.

50 100 250 500

H, PO,

Gehait ^? i

0.024
0.024
0.024
0.024

Polycondensation time

2h30
2 hours 25
2h7
2h20

Properties of the polymer

VZ ² )

0.68 0.68 0.68 0.68

EG COOH ')

26th

25 22 23

EP C)

259.5 260 262.5 261

The polymers obtained by the process according to the invention are very white and in particular have a very high heat resistance that is just as good. like those with aluminum oxide obtained polymers.

Comparative heat treatment tests were carried out

at 185C in air for 10 hours on polymers obtained with antimony oxide and on after the polymers obtained in Examples 4 to 7 in Table II illustrated processes according to the invention accomplished. The results obtained are shown in Table III.

Crowd') Table III Quantity ¹ ) In front the EG To the EG modification
of properties IEG 180 Pohkondensationskatalvsator 50 Heat treatment COOH ³ ) Heat treatment COOH ^J ) of the polymer COOH Transesterune catalyst 180 100 26th 29 3 180 250 VZ-) 25th VZ ² ) 29 IVZ 4th 180 Art 5 (K) 0.68 22nd 0.68 28 0 6th Art 180 Triethanolamine 340 0.68 23 0.67 24 0.01 1 Calcium acetate the same 0.68 25th 0.65 29 0.03 4th the same the same 0.68 0.68 0 the same the same 0.67 0.65 0.02 the same Sb ₂ O, the same

'). ') and ') have the same meanings as in Tables I and

In the case of puncturing, too, S'.ick ^ loff determinations were made carried out with an accuracy of 10 ° ο, which showed that all of the triethanolamine introduced was found in the polymer. Nevertheless the polymers are uncolored, as already mentioned. In the following Table IV these are Results collated.

Table IV

Introduced Tnethanolami '
Menae'i

100
250

By anahse

found triethanolamine

Quantity ^: ι

UO
230

bm-stirred triethanolamine
Menue'i

By anal} se

found triethanolamine

Quantity ¹ 1

500
has the dykes

480

Meaning as in T.ibdlen 1. II and III.

Finally, spinning and drawing tests have shown that according to the invention .υ process obtained polymeric threads with normal Properties were obtained.

For example, for a thread with a

Titer of 45 den. 22 monofilaments, which at 285 'C with was spun at a speed of 900 m min and drawn to a degree of 3.6. the Strength in grams of 4.60 for an elongation of 24 V.

Claims (1)

! 645 399 Claim: Process for the production of linear polyesters by polycondensation of bis ('·' hydroxvalkvD-terephthalates or their ohgomers Γη presence of a polycondensation catalyst containing a nitrogen atom, thereby oekennzeiehnet.das one as a polycondensation catalyst Triethanolamine used.