DE2303350A1 - NEW PROCESS FOR MANUFACTURING POLYESTERS AND THE PRODUCTS OBTAINED THIS - Google Patents

Description

I *. F. Zumsteln sen. - Dr. E. Assmann DcJLKoenigsberger - Dipl. Phys. R. Holzbauer

Dr. F. Zumsiein jun. Patent attorneys Munich 2, Bräuhausstraße 4 / III

DT 3778

RHONE-POULENC-TEXTILE, Paris / France

New process for the production of polyesters

and the products thus obtained

Synthetic polyesters derived from dicarboxylic acids and diols, which can be converted into textile products are known.

Among these, the most common ones obtained from aromatic dicarboxylic acids and a diol of the formula HO- (CHg) _n -OH, in which η is an integer between 2 and 10.

One of the ways in which these polyesters are made involves transesterification between an alkyl ester of the dicarboxylic acid and a diol, which leads to a BiS (W -hydroxyalkyl) diester, namely in an « Essence of a suitable catalyst, this diester is then in a vacuum in the presence of a polycondensation « Katälysators heated, whereby the polyester is formed and where- * with the excess diol is removed.

Such a method has certain disadvantages

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the use of an increased amount of diol, generally at least 2 moles per mole of ester of the dicarboxylic acids what requires »at the beginning a reaction vessel with a large volume with increased heating power to provide, and also requires the excess of the diol formed in the course of the polycondensation reaction with the whole Energy consumption that this requires,

the need to use a transesterification catalyst, generally a metal salt such as zinc «, manganese, calcium or Cobalt acetate or the like should be used, which is mostly disruptive Leads to coloration or degradation reactions during the subsequent processing of the polymer,

Side reactions as a result of the dehydration of the diol, which is all the more are stronger, the higher the molar ratio,

the requirement to make a second during the polycondensation itself Catalyst, such as antimony derivatives, molten lead and. like, to use.

A well-known variant is the one where you use the usual mineral polycondensation catalyst through triethanolamine replaced, which is introduced in very small amounts, which leads to uncolored polymers (French patent 1,490,477).

Another known variant of this process consists in using only a single catalyst for the transesterification and polycondensation reactions, such as an organic titanium derivative, for example of the type T10 «P ^R v * ^where R is any mono- or polyvalent radical (French patent specification 1 153 698).

In this latter case the molar ratio diol / ester can be aromatic dicarboxylic acid are significantly reduced, since the polycondensation reaction before the end of the transesterification of the Alcohols begins. There can be mole ratios close to the

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Unit can be used, which of course has a considerable " lent economic advantage.

In this process, however, it is not possible to use the transesterification catalyst to "block", as is usually done with the metal salts with a phosphorus compound, since this blockage « evidently a slowdown or even an inhibition * - bation of the polycondensation reaction would bring with it.

It is therefore necessary to use the organotitanium catalyst during the entire duration of the reaction chain: transesterification-polycondensation tion free.

Due to the lack of the blocking agent, the polymers obtained are extremely poor in heat resistance. While the contents of the autoclave are being poured, a considerable drop in viscosity between the beginning and the end observed what leads to a heterogeneous polymer «, In addition, the drying and, which is essential for subsequent shaping, lead to Remelting leads to severe degradation and thus to much poorer mechanical properties of the end product,

The present invention relates to a process for the production of polyesters and copolyesters based on aromatic compounds Dicarboxylic acids and diols having at least 3 carbon atoms in the presence of an organotitanium derivative by transesterification between an alkyl ester of the aromatic dicarboxylic acid or dicarboxylic acids and the diol or diols and subsequent polycondensation, which is characterized in that in the stage of the polycondens " sation 0.001 to 1 wt, - #, based on the polymer to be formed, of a non-volatile amine can be added.

The presence of such an amine enables a reduction the duration of the transesterification ^ polycondensation cycle, the

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usual competing degradation reactions during the formation of the Polymers are strongly inhibited. The amine plays the role of a very effective protective agent against that caused by the organic titanium derivative caused degradation, the organic titanium derivative can be found among the alkyl titanates, orthotitanates or polytitanates to be chosen »

As a non-volatile amine usable according to the invention with a Boiling temperature above 200 ° C under normal pressure, for example, triethanolamine, trioctylamine, tribenzylamine and ben call zyldiethanolamine "

The method according to the invention can be carried out in the presence of a poly functional branching agent or an adjuvant, such as for example a matting agent, for example titanium oxide, or one Colorants, such as pigments or dyes, through « be performed without leaving the scope of the invention.

The polyesters produced in this way have great homogeneity in terms of melt viscosity. In contrast to polyethylene glycol terephthalate, in which the formation of aldehydic products leads to disruptive colorations in the presence of an amine, the colorimetric properties of such polymers are excellent due to the reduction in polycondensation times. There will be no degradation during drying and remelting determined during processing of the polymer "As a result" of this, the mechanical properties, heat resistance, the resistance to oxidation and hydrolysis of the? products obtained improved.

The general manufacturing conditions are as follows:

In a stainless steel autoclave equipped with a device for moving and means for creating a vacuum and regulating devices, you bring the.

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Diesters or the diesters of the dicarboxylic acid or of the dicarboxylic acids, the diol or the diols and the catalyst. The temperature is gradually increased until the transesterification of the alcohols has ended. When this step is complete, the non-volatile amine is introduced in such an amount that its concentration is between 0.001 and 1% by weight, i.e., 10 to 10,000 parts per million (ppm) in the final polymer. This amine can in particular be dissolved in the diol, which optionally contains titanium oxide in suspension. The polycondensation is then continued in a vacuum of the order of magnitude of one Torr, the temperature gradually increasing up to a value which can be between 250 and 500 ^° C. When the melt viscosity of the polymer has reached the desired value, it is poured into water, granulated and dried.

The following examples, in which parts are expressed as parts by weight, serve to further illustrate the invention. The following applies to these examples:

is the melt viscosity of the polymer (VP), expressed in P measured by means of a Davenport-J extrusion plastometer,

the viscosity number (IV), equal to 1000 («- 1 / c), is measured at 25 * C with a solution with 1% (weight / volume) of the polymer in o ~ chlorophenol, the concentration (c) in g / l is expressed

the degradability of the polymer is assessed by measuring the melt viscosity before (VP ₁ ) and after (VPp) a treatment under nitrogen for 30 minutes at a temperature of 250 * C or 260 * C depending on the polymer, which gives AVF = VF ^ - VFg,

the determination of the number of terminal groups -COOH per ton Polymer (GT) is made by colorimetric determination,

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■ »ο · *

the lightness (Y #) and the degree of yellowness (U) are measured on an Elrepho (Zeiss) photocolorimeter using the method described in the second edition of Kirk-Othmer ^! s Encyclopedia of Chemical Technology (John Wiley, 196 ^) Volume 5, pp. 802 to 805.

example 1

In a first experiment, an autoclave is charged simultaneously with 2910 parts of dimethyl terephthalate, 1530 parts of butanediol (1.4) and 0.66 parts of triethanolamine orthotitanate. The transesterification of the alcohols begins at 160 ° C. Simultaneously with the distillation of the methanol after one hour, the pressure is gradually reduced to 100 Torr within 50 minutes and held at this value for one hour. The temperature of the mass is then 220 ^° C. After releasing the vacuum with nitrogen, 66 parts of a 20% strength by weight suspension of TiOp in butanediol which contains 0.66 part of triethanolamine orthotitanate are added. The pressure is quickly brought back to 300 torr. A vacuum of 0.5 Torr is then applied in 45 minutes while the mass is brought to 260 ° C. The polycondensation continues for 1 1/2 hours and the polymer is then poured *

In a second experiment carried out using the same procedure, the suspension of TiO ₂ in butanediol contains not only titanium oxide and the second fraction of the polycondensation catalyst, but also 1.65 parts of benzyl diethanolamine, an amount corresponding to 500 ppm, based on the polymer. ^;

The table below gives the melt viscosity values of the two polymers, and it is shown that the The initial value of Experiment 2 is higher than that of Experiment 1 and that the decomposition in the molten state in this latter Attempt is much higher.

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Experiment VP ₁ (at 260 * C) VFp (after heat

treatment at 260 * C)

1 3 160 2 300 860

2 3 650 3 500 t5O

Examples 2, 3 and 4

In a comparative experiment, 29IO parts of dimethyl terephthalate, 1530 parts of 1,4-butanediol and 0.66 parts of triethanolamine orthotitanate are simultaneously introduced into the autoclave. The transesterification of alcohols starts at i60 C ^e, concurrently with distillation of the methanol after one hour the pressure is progressively decreased to 300 Torr over 50 minutes and held for one hour at this temperature. The temperature of the mass is then 220 ^° C. After releasing the vacuum with nitrogen, 66 parts of a 20% strength by weight suspension of TiO ₂ in butanediol which contains 0.66 part of triethanolamine orthotitanate are added. The pressure is quickly brought back to 300 torr. A vacuum of 0.5 torr is then progressively applied over 45 minutes. The polycondensation is continued until the force required for stirring has reached its maximum. Glessening takes 50 minutes,

In the examples, triethanolamine is converted into butanediolic pension brought in in variable amounts.

The results obtained are summarized in the table below:

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example Content of tri-
ethanolamine in
ppm / polymer Vf ₁ Vf ₂ GT
«COOH Y % IJ comparison O 4450 3820 53 73.7 18th 2 100 6150 496O 50 72.6. 20th 3
4th 200
500 6450
7100 5460
6500 46
43 70.4
73.9 23
15th

Vf means the viscosity of the polymer at 260 ° C. after 5 minutes Casting in P.

p means the viscosity of the polymer at 260 ° C after 45 minutes « tigern pouring in P.

Examination of the values in this table shows that the resistance of the polymer against degradation with the amount of triethanolamine introduced increases

Example 5

In a first attempt, 29 100 are placed in an autoclave Parts of dimethyl terephthalate, 15,300 parts of butanediol (1,4) and 6,6 Classify triethanolamine orthotitanate. The transesterification of the Aiko ™ hole starts at 16O * C «After 2 1/4 hours is the theoretical Amount of methanol distilled off. The temperature of the mass reaches 245 * C. 66O parts of a 20% strength by weight suspension are then used of titanium oxide in butanediol and 6.6 parts of triethanolamine orthotita «nat. The pressure is lowered to 1 torr in 40 minutes while the mass is brought to 260 ° C. The polycondensation is continued for 55 minutes at this temperature. The polymer will then poured.

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In a second experiment the butanediol suspension contains, in addition to " the 33 parts of trioctylamine.

The properties of the two polymers obtained are summarized in the table below:

attempt ^{Ί ¥} \ (26ο σ) IV 1
2 3 6oo
4,200 117
120.5

Example 6

1940 parts of dimethyl terephthalate, 1298 parts of hexanediol (1.6) and 2 parts of butyl polytitanate are introduced into an autoclave. The transesterification of alcohols begins at 148 ° C and the theoretical amount of methanol is distilled off in about 11/2 hours, the temperature of the mass is then 240 ⁰ C. A vacuum of 0.2 torr is applied over the course of 20 minutes while the mass is brought to 265 ^° C. The polycondensation is continued for 2 1/2 hours "Then the polymer is poured into water"

This polymer is used as comparative au a second experiment, which is carried out under the same conditions, but in which 2.5 parts of triethanolamine are added at a temperature of 220 C ^6. These two polymers have the following properties:

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attempt ^W 1 (250 ^# C) colour comparison
Example 6 1,660
2,220 white, bluish
white, purple

Example 7

23,280 parts of dimethyl terephthalate, 5,820 parts of dimethyl isophthalate, 15,300 parts of butanediol * - (1,4) and 6.6 parts of triethanolamine orthotitanate are simultaneously introduced into an autoclave. After 2 1/4 hours the theoretical amount of methanol is distilled off, land the temperature of the mass reaches 245 ^e C. is then added 660 parts of a 20 wt «~ # suspension of TIOP in butanediol and 6.6 parts Triathanolaminorthotitanat to. The pressure is reduced to 1 torr in 40 minutes while the mass is brought to 260 ° C. The polycondensation is continued for 55 minutes at this temperature. The polymer is then cast.

Another experiment is carried out in parallel, in which the butanediol suspension contains 33 parts of trioctylamine in addition to the titanium oxide and the triethanolamine orthotitanate.

The properties of the polymers obtained are as follows:

attempt ^W 1 (260 * CX IV comparison
Example 7 3 400
3 700 116
120

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Claims (1)

- 11 "
Claims Process for the preparation of polyesters and copolyesters based on aromatic dicarboxylic acids and diols having at least J carbon atoms in the presence of an organotitanium derivative, the preparation being by transesterification between an alkyl ester of the aromatic diacid or the aromatic diacids and the diol or diols and subsequent polycondensation is carried out, characterized in that 0.001 to 1 percent is _e «#, based on the polymers to be formed, is added to a non-volatile amine is in the stage of polycondensation, 2, The method according to claim 1, characterized in that the polycondensation reaction in the presence of a polyfunctional Branching agent is carried out. 3 _# polyester and copolyester obtained according to claim 1 or 2, 4 ″, threads, fibers, films, foils, moldings and extruded Products obtained from polymers according to claim 3 « 309831/1730