DE1905188B2 - - Google Patents

Description

A general method for making polyalkylene terephthalals is that Terephthalic acid or its lower aliphatic ester with an alkylene glycol of the general formula

HO-ICHj) _n -OH

40

in which η means 2 or an integer which is greater than 2, converts to bis (hydroxyalkyl) tcrephthalate and then produces polyalkylene terephthalate therefrom. The reaction is thus carried out in two stages, the bis (hydroxyalkyl) terephthalate in the first and the polyalkylene terephthalate being produced in the second by polycondensation of the bis (hydroxyalkyl) terephthalate. In both stages different Kalal> salorcn are used.

There are already many publications with regard to the catalyst for polycondensation. For example, British Patent 740,381 describes antimony compounds which are soluble in the reaction system. Dutch patent specification 97 835 describes cobalt compounds. Japanese Patent 288,887 and British Patent 793 111 name titanium compounds. However, the known catalysts are unsatisfactory in terms of color tone and various physical properties of the polyesters obtained.

The object of the invention is therefore to provide a method which uses a suitable catalyst provides colorless polyesters with excellent physical properties.

Organic titanium compounds have now been mainly used as catalysts for polycondensation. These compounds are usually soluble in the reaction mixture and have a high catalytic activity. However, the polymers obtained are colored yellow or brown, so that these compounds are difficult to use in practice.

It has now surprisingly been found that metallic titanium is catalytically active, the Activity very high and the polymer obtained is not colored at all. When comparing with Antimony trioxide shows that when using the known catalyst, the polymers obtained yellow-green in color, while titanium provides a completely colorless and transparent polymer. Furthermore, it has been shown that with regard to the further physical properties, i. H. the number the carboxyl groups, the melting point, the polymers obtained with titanium are far superior.

The invention therefore relates to a process for the production of polyalkylene terephthalate ^! and modified polyesters comprised of at least 75 mole percent of a polyalkylene terephthalate and up to 25 mol percent consist of units that are formed from at least one further ester-forming component, namely an aliphatic diol, a polyethylene glycol, an aromatic diol, an alicclic diol, an aliphatic dicarboxylic acid. derive an aromatic dicarboxylic acid or an acyclic dicarboxylic acid, by polycondensation of bis (hydroxyalkyl) terephthalate. optionally in a mixture with less than 25 mol% the other component, in the presence of a metal catalyst, which is characterized by it. that titanium is used as the metal catalyst.

From the French patent specification I 509? () 6 i> t it is already known that the 1 lerstelkini · from Polyethylene terephthalate as a catalyst for the pol \ - can use kondensalion titanium dioxide gel hydrate. but in this pamphlet the usage! from metallic titanium not mentioned or suggested.

According to the procedure of the French Patent Schi ift I 410 481 polyethylene terephthalate is only used made of antimony powder as a catalyst. Notes on the use of metallic However, titanium is not found in this publication either.

In Belgian patent 636 944 metallic titanium is used in connection with Jcr production described by polyesters, but there is; · metallic titanium as well as certain metal oxides. z. B. zinc oxide, titanium oxide only as a Vcrcslcrungskalalysator used when terephthalic acid with ethyl glycol to bis (/ miydroxyethyl) -lcrcphtha IaI implements. After this reaction the metallic Titanium is filtered off and the polycondensation takes place in the presence of another catalyst. So came The only conclusion drawn from this publication is that metallic titanium is an esterification '; catalyst is suitable.

Investigations with metallic titai were carried out carried out in the form of finely divided particles coarser particles and of other small form bodies, like blocks, flakes, shavings. Shavings ribbons, composed of fine wires! Nets, small balls or fine granules were in front of them. As a result, it was found that all of these For Men are suitable as a catalyst.

Various experiments were also carried out in which the reaction vessel or at least egg

Part of the accessories that came into contact with the reaction mixture, made of metallic titanium or a This alloy was mainly made from this metal. The polycondensation takes place through the catalytic effect of the reaction vessels or the accessories, whereby it was determined that a permanent and uniform polycondensation took place.

First of all, the use of fine titanium powder, which is one of the cheapest forms of ErHnto tion represents, are explained in more detail.

When using metallic titanium as a catalyst, it is advisable to use the titanium in the form of a finely divided powder to increase the contact surface for more uniform dispersion in the reaction system. The results of various experiments decompose the maturity of the catalyst -, / ur Beicrik-uigungder V-olykondcnsaiion with the Teilchenjio ¹ .. '! it varies powder the, catalyst used in the PoUkondensat · · · remains in the.' general ^ l '-' m polymers and is in the subsequent! ·: ■ eifahrensstufen not removed, mi that he 111 to purchasers after spinning remains Thus, ^{bc; ':::} n certain limitations dci (ic τ nil the Teilcln-i · blacks and the amount of as Katah -... .atnr eintet / -: .s bar; · - powder.

Y: h.il been found that at an average particle size de metallic titanium \ on less than ^i: "1 ί the desired results can be obtained and that the use of powders with high w -ens 30 μ preferable isl Furthermore. If the average particle size can be adjusted to a maximum of 3 μ, which can be done by suitable selection of the conditions of the powder, sieving and, if necessary, further auxiliary measures the quality of the polymer obtained, 1 and the threads are particularly preferable.

In addition, the fcinwrleilie l'iher has a very high dispersion stability in Gi \ kol.

As already mentioned, cause! According to the invention, m.-tailisehe titanium used in the polymer no undesirable VeiTirbiin.r. to yellow or brown, so that the added menr.e nichl v < Sd must be limited critically. never at VVrvenduni; of antimony compounds and c.'i.-r of other known catalysts. At a certain einc.i Titangehall amount exceeding however a t'iiin black F ^tr'll: ärbung. as -i _e since the catalyst itself has <, o on. It is therefore advisable to avoid the addition of more than 1 percent by weight and, in particular, when a white appearance is required, to limit the amount to 0.1 percent by weight. v-,

Now is to use a rcl; ilit urölx'icn Titans are explained according to a further embodiment of the method according to the invention.

The stirring reaction to form the polyester is an equilibrium reaction. so that additionally / u fto the formation reaction always has the back reaction. d. h the depolymerization can take place. Since the catalyst which accelerates the formation reaction, also catalyzes the reverse reaction at the same time, it is advisable to the catalyst after the end of the polycondensation to quickly remove the ion from the polymer to allow decomposition reactions of the polymer to avoid.

As conventional catalysts for the production of polyesters, substances soluble in the reaction system have been used. In some cases, insoluble fine particles can also be used. However, in any of these cases, the separation of the catalysts from the polymer is difficult, so that the catalysts remain in the polymer. So humiliating! When the polymer is melted again during the subsequent spinning, the viscosity of the polymer increases due to the decomposition that takes place. In addition, undesirable discoloration occurs. These disadvantages pose great problems in the production of polyesters. Furthermore, when fine metal particles are used as catalysts, these are often incorporated into the spun thread, so that button formation and breaking of the yarn are disadvantageous. When using relatively coarse metallic titanium, for example blocks. Flakes. Schnitzel. Chips. Ribbons, nets composed of fine wires, small spheres, fine or coarser granules, the catalyst can, however, be separated quickly from the polymer by simple filtration. In this way, polymers can be produced which have little or no more catalyst. If the titanium catalyst is used as coarse granules with a longitudinal diameter of more than 100 -j. is present, most of the grains are filtered out by a filler used in spinning. so that the above bev.fine; r! Disadvantages can be reduced considerably. With regard to the Filtrationswir '; samkei (higher particle sizes are desired, but the usable surface iii ^r the catalytic activity m this case reduced and the analytical capacity compared / u the same amount of finer Ί eilchen low .wurden In this connection!. various i 'nlcrsucimngen angesle ^1;!. which have resulted dal..' since the Kjia'ysaforwirkung jh by greater agitation and dii a giößeren portion can be increased, it is quite useful in Anbetrcht filtration effect wedge powder having a Tcilclicnüiöße '.'. Min more than 200 years to be used if the oui'li ':!'. Of the PoK kidney and of the yarn as weighed crac'.lci., With particle sizes of over 50 nisi, the filtration efficiency is sufficiently high.

The catalytic activity of metallic titanium ■ si actually r-.o high that already coarse powder or B'öckc are catalytically active.

Metallic titanium is usually very stable and is harmful · de · ^1, the human body P'dit.

Fs is na'u'ficmäi 'z.weckn-.äiJig. metallic fitar use of high purity 7> \, d'.tch brings the presence of small amounts of Verunrcinigunger wgö Zvisal / f.'ioffcn no wesc '^ iiclicn disadvantages mi located ,. In the case of starting materials for synthetic fibers, it is preferable if there are strict restrictions on the discoloration of the polymers, metallic titanium with; a net content of more than Wz; to be used When Vepvend.ing of! nclaliischen Titan with lower purity must with uiv.T.varl · ': ..! Fischeinungeri are expected. In ncuerer 7, a method for cleaning titanium was so far developed. that high-purity titanium with a purity of mc'ir as 9 ⁽ ) "n can easily be supplied. The use of such a metalusdiei titanium is particularly recommended.

The metallic titanium calalyzatov can according to the Use of the polymer will be separated

and remains in the reaction vessel. Dubei was no significant decrease in the catalytic! Activity observed so that the catalyst can be used several times.

When using metallic titanium in piece torrn or as granules, the catalyst can be used according to the Polycondensation can be removed during extrusion. As a result, the polymer obtained is never discolored. The other various properties are also the same as those using the conventional ones Catalysts, e.g. B. Antimony trioxide, produced polymers superior.

When using the titanium catalyst in relative coarse form, such as coarse granules, flakes, chips, shavings, ribbons or fine wires the catalyst so quickly on the bottom of the reaction vessel that the dispersion of the Catalyst is likely to be insufficient. Therefore, good mechanical agitation should be ensured will.

It has also been found that then one steady and uniform reaction takes place if one part of the reaction vessel which is holding the reaction mixture comes into contact or at least part of the accessories, for example the stirrer. made of metallic titanium or an alloy consisting mainly of titanium. The reaction however, it can already take place sufficiently when the part of the system that involves the RaIK-ticnsmixture is in contact, completely or partially coated with titanium or an alloy containing titanium is. This kar.ii, for example, by dressing up. Plating or gluing can be achieved. This is true also for projections, grooves, folds or projections / u that are on the inner wall of the vessel and the Inner / parts, such as pipes. Lattice, perforated plates. Meshes, partitions or multi-level panels are provided are. "Accessories" fall under the designation z. B. stirrers, small plates, chains, rings, fine wires and nets, which are provided on the stirrer together with this to rotate. The same applies Screws or washers used in devices for continuous: · Polycondensation This embodiment is special for a continuous polycondensation process gceigr.et.

Lately there is an increasing interest in a continuous. Polykondensationsverfahren emerged, and a large number of studies have already been carried out on this. One of the most important Problems are posed by the difficulty of adding and relocating the catalyst uniformly represents. In the above-described Ausfühiungsform the invention now acts the reaction vessel itself as a catalyst, so that the separate No need for a catalyst. The liquid one Reaction mixture) is used during the entire reaction, at which the polycondensation is completed. {"Vichförmii; inugueguiert and stands with the Inner surface of the reaction vessel. acting as a catalyst acts, in touch. Thus, the disadvantages described above do not arise. so that a polymer with high uniformity can be obtained. The catalytic effect of the titanium alloy varies accordingly the conditions of the polycondensation, bcbeispielswt're according to the contact area and the stirring speed. The higher the titanium content. the bigger it is catalytic ^ effect, so that in general alloys with more than 75 percent by weight of titanium, preferred.

According to the process of the invention are polyalkylene terephthalates, such as polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate, Polyhexamethylene terephthalate can be produced. The modified polyesters are obtained by using them as well less than 25 mole percent of the others

ίο component.

The modified polyesters which can be prepared according to the invention consist of up to 25 mol percent of units which differ from an aliphatic diol (excluding the alkylene glycol, a main component of polyalkylene terephthalate), such as ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol. Hexamethylene glycol, polyethylene glycol, like diethylene glycol. Triethylene glycol: aromatic diol! Such as catechol. Resorcinol, hydroquinone; alicyclic diol, such as cyclohexanedimethanol, cyclohecanediol an aliphatic carboxylic acid such as adipic acid, sebacic acid. Decanedicarboxylic acid; aromatic Dicarboxylic acids such as phthalic acid, isophthalic acid. Sodium sulphoisophthalic acid, sodium sulfoterephthalic acid. Naphthalenedicarboxylic acid; alicyclic dicarboxylic acids, such as hexahydroisophthalic acid, Derive Hc-.xahydroterephthalic acid.

The presence of titanium oxide as a matting agent, pigment. Dye, fluorescent luster and of other additives generally used in polyester has on the process of Invention no influence.

The invention is illustrated in the examples. In these examples mean "parts" if nothing else indicated, parts by weight.

example 1

Into a reaction vessel equipped with a stirrer, an inlet for nitrogen gas and an outlet for nitrogen gas and by-products had sunk, KXl parts were dimethyl terephthalate. 70 parts of ethylene glycol, 0.015 part of zinc formate and 0.017 part of triethyl phosphate entered. The mixture obtained became rapid with the introduction of gaseous nitrogen heated to 170 C. 30 minutes after the temperature 170 C had reached, the stirrer was with a Stirring speed of 60 rpm turned on. The temperature of the jacket of the reaction vessel was then determined increased by 10 C every hour. The Estcraustauschrcaktion was stopped after 7 hours at 240 ° C. The course of the reaction was determined by determination of the distilled Mettumol determined. At the end of the reaction, the ester exchange was 98%.

To prepare the catalyst for the polycondensation metallic titanium with a purity of 99.9% became 72 hours with 4 times the amount of ethylene glycol ground in a porcelain ball mill.

It was then diluted with ethylene glycol to such an extent that a 5% dispersion was obtained. These was left to stand in a cylindrical jar for 24 hours. The one at the bottom of the cylindrical Coarse particles deposited in the vessel were removed from

6 ;; the dispersion containing fine particles carefully separated and the concentration of the tilane in the Determination of dispersion. The dispersion was then diluted to 1 percent by weight titanium with alien glycol.

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The size distribution in the dispersion was determined after starting phases. The average particle size was 2.4 μ.

A certain amount of de, "prepared in this way Titiindispcrsion became the obcnbcschricbencn Ester interchange reaction product given. On that was the temperature of the jacket of the reaction vessel. ·; increased to 280 <"over the course of one hour. The mixture was stirred and nitrogen gas was passed in. The gases in the reaction vessel were then sucked off by means of a vacuum pump in order to Lower the pressure in the reaction vessel to 0.3 mm Hg. In this state, the polycondensation reaction took place continued. As the reaction proceeded, the viscosity of the reaction product and the / the electrical energy required to operate the stirrer. The electrical energy was from both the size and shape of the vessel and the stirrer, as well as the viscosity. the Relationship between the electrical energy required to operate the scrambled egg and the viscosity the content has already been determined in advance. When the ■ icctric energy reaches a predetermined value

Then the emotion was interrupted and ιi ■ _-1- Operation of the vacuum pump set. To end nitrogen gas was introduced into the reaction. (The time it takes to reach the vacuum \ .m 0.3 mm Hg until the reaction has stopped is called »polycondensation time in vacuum«.) The reaction product was removed from the bottom of the vessel and cut into small chips.

A series of tests was carried out by changing the amount of the titanium dispersion added. The polycondensation time was measured. Furthermore, the properties were obtained Polymers determined and with those obtained when using antimony trioxide as a catalyst Products compared. These results are shown in Table I.

The viscosity of the polymer is called the intrinsic viscosity in a mixed solvent of ethane tetrachloride and phenol (40/60 percent by weight) at 25 "C. This can be seen from the following Formula:

[»,] = Lim

in which η means the relative viscosity at a polymer concentration of C (g) / 100 cm ³ .

The number of carboxyl groups is given as carboxyl group equivalents / 10 ⁶ g of the polymer. This quantity was determined by titrating the polymer in benzyl alcohol with potassium hydroxide.

The melting point was determined on a hot bench. It indicates the temperature at which the Half of the sample has melted.

Table I.

- - -
Kalaljsator- "
Polycondensation Intrusive
Visibility C'iirbowl- 1 Melting point Color of the polymer KiiUilysiilor mcngc saltonsreil im
vacuum uruppcn / uhl I weight Equivalent. 10 ^ft g percent) (Hours ) 0.65 261.5 colorless Metallic titanium 0.0025 4th 0.63 20.2 263.0 colorless 0.005 2 ^{1 line} ₂ 0.66 13.4 262.5 low 0.03 WU 19.3 Gray coloring 0.73 262.5 easy 0.1 I. 25.6 Gray coloring 0.82 261.0 Gray coloring 1.0 I. 0.69 20.0 259.5 light yellow-gray \ ntimontrioxide 0.03 3 29.7 coloring

From Table I it can be seen that the inventive Used catalyst a very good katah compared to the conventional catalysts has table activity. The polymers obtained therewith have excellent physical properties and show no disadvantageous yellowing.

The catalyst showed even when the titanium dispersion was added to the mixture of starting materials was added before the ester interchange reaction started, the same activity. Here, too, were polymers with the same properties as in Table I.

60

Example 2

Spongy metallic titanium (with a purity of 99.2%) was roughly crushed and then in a porcelain ball mill with 4 times the amount by weight of ethylene glycol specified in the following Grind for the times given in the table. Then was with ethylene glycol to dispersions with a Diluted titanium content of 1 percent by weight. The average particle size in the dispersions was determined according to Andrehasen. 0.5 parts of the individual dispersions (which corresponds to an amount of titanium of 0.005 percent by weight, based on the polymer, corresponds) were weighed and obtained according to Example 1 Ester interchange reaction product added. The polycondensation was then carried out according to Example 1 performed.

It was found that the smaller the particle size. the shorter the required for the polycondensation Time was so that side reactions and thermal decomposition practically do not occur and Polymers with better physical properties could be obtained.

When the average particle size was 121 α, the catalyst fell into the reaction mixture so that it was necessary to increase the rotating speed of the stirrer to three times the normal value raise. The results of these tests are shown in Table II.

409 539/345

10

TabcllcII

Grinding rate (SkU

Average particle size i; i)

Polykonclcnsiitions / .cit im
Vacuum (style.)

Stirring speed (rpm) ..

Intrinsic viscosity

Number of carboxyl groups, equivalents / 10 "g

Melting point ("C)

Color ion of the polymer

12th 24 48 72 72
(sifted) 121.4 86.2 38.7 22.5 2.4 180
0.53 60
0.61 6 ^_3/4
60
0.60 47 *
60
0.70 27a
60
0.63 28.6
260.0
light yellow 20.4
261.5
very light yellow 25.1
260.5
very light yellow 18.7
262.5
colorless 13.4
263.0
colorless

Example 3

In the reaction vessel according to Example 1 were 85 parts of dimethyl terephthalate, 15 parts of dimethyl isophthalate, 70 parts of ethylene glycol, 0.015 part of zinc acetate, 0.02 part triphenyl phosphite and 0.4 part titanium oxide introduced as a matting agent. Then an ester interchange reaction was carried out according to Example 1. The percentage ester exchange, calculated from the amount of methanol distilled off, bctrup 35%.

The catalyst was prepared by leaving crushed titanium in a ball mill for 72 hours was ground with ethylene glycol. The milled titanium was then mixed with ethylene glycol to form a dispersion diluted with 5 weight percent titanium. After allowing the coarse particles to sit for 24 hours separated and removed from the dispersion of fine particles.

The titanium dispersion thus obtained became the above in the amounts shown in Table III Ester interchange reaction product added. The polycondensation was then carried out as in Example 1 performed. The required reaction time and the characteristic properties of the obtained Polymers were produced with the corresponding values when using antimony trioxide as a catalyst compared. As a result, it was found that even if the amount of the catalyst used was less than that conventional catalyst, the reaction in the use of the catalyst according to the invention was completed in less time. Feiner showed that the polymer produced according to the invention with regard to its physical properties and its color shade compared to conventionally produced polymers was superior. The results are shown in Table III.

Catalyst- Polykoidensa- Table III Carboxvl Melting point Color ion of the polymer lot.
Weight
percent tionzcit in
vacuum group number.
Equivalents /
10 "0 IC) catalyst Polymer (SId.) Intrinsic
viscosity 221.0 White 0.005 27 * 15.6 221.0 White Metallic titanium 0.025 17 * 0.61 18.2 220.5 light gray 0.04 174 0.65 27.2 220.5 light yellow 0.04 3 0.71 24.8 the Polvkon ^ .nsntinrrikntalvsat Antimony trioxide Example 4 0.72 Furthermore, was

1 η a stainless steel autoclave equipped with a stirrer, an inlet for nitrogen gas and a Outlet for nitrogen gas and by-products, which in turn is connected to a fractionation column was provided, 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, 0.015 part of zinc formate and entered 0.017 part of triethyl phosphate. The whole thing was done while bubbling nitrogen gas heated. 30 minutes after the temperature is 170 ° C had reached, the stirrer was started at a speed of 60 rpm. Then the temperature of the autoclave jacket was increased by 10 ° C every hour. The ester interchange reaction was stopped after 7 hours at 240 ° C. The ester exchange was calculated from the amount distilled off Amount of methanol, 97.5%.

made by Schwainm-shaped titanium metal blocks were roughly crushed with a purity of 99.5% and the crushed titanium was sieved to obtain coarse particles with a particle size of i 00μ - 3mm.

The amounts shown in Table IV were added to the ester interchange reaction product. The temperature of the autoclave jacket was then increased to 280 ° C. within one hour. It was Introduced nitrogen gas. In this case, the stirrer was set at a stirring speed of 150 rpm put into operation to prevent the separation of titanium particles. After the temperature Reached 280 ° C, the autoclave pressure was reduced from atmospheric pressure within one hour! a vacuum pump lowered to 0.3 mm Hg. To-

When the viscosity had risen so much. that the ^ separation of the catalytic converter was prevented. the stirring speed was reduced to 60 rpm and the polycondensation reaction was stopped, when the viscosity almost reaches the desired value would have. The viscosity of the reaction product was determined from the stirrer motor consumption (en electric Energy appreciated. The operation of the vacuum pump and the rotation of the stirrer were

broke. Nitrogen gas was passed into the autoclave and the reaction product from the bottom of the Autoclave extruded under nitrogen gas pressure in the form of a string. The extruded string became shavings cut up. When extruding the polymer, the titanium particles were through a at the bottom of the Reaction vessel provided filter removed.

The results obtained are summarized in Table IV.

KaUl) sii! Or-
nienpc,
Weight
percent
Polymer Polykonilciisa-
lionszcil im
vacuum
(Stell Table IV C'arbiml-
pruppen / ahl.
Equivalents
10 "g Melting point Color of the polymer catalyst 0.5 6th Inlrinsic
Viscosity 29.3 260.5 light yellow Metallic titanium 1.0 4 '/ ₂ 0.65 22.5 260.0 colorless 3.0 2 ^_3/4 0.61 16.1 260.5 colorless 5.0 l ^! / 4 0.60 13.4 262.5 colorless 10.0 5,
/ (I 0.60 12.0 262.0 colorless 0.03 4th 0.63 27.3 260.0 light yellow green Antimony trioxide 0.65

From Table IV it can be seen that the catalyst of the invention gives polymers with very good properties. In particular, the polymers obtained are excellent in terms of color, which can be attributed to the absence of the polycondensation catalyst is. In addition, the separated from the polymer and remaining in the reaction vessel can Catalyst can be used repeatedly.

Example 5

A titanium plate made of high-purity titanium with a purity of over 99.5% was made by means of an electric Drill cut into strips of metallic titanium. The tapes were average Width of 4 mm and a thickness of 0.3 to 0.5 mm. They have been cut to make their longest section was not larger than 5 mm. To the ester interchange reaction product obtained in Example 4 the amounts of this catalyst indicated in Table V below were added and then carried out the polycondensation reaction. In this case was in the primary polycondensation stage the stirring speed 150rpm until the viscosity of the reaction product became so high, that the deposition of the catalyst was avoided. After the viscosity reaches this value hold, the stirring speed was reduced to 60 rpm. When extruding the polymer the catalyst was removed therefrom through a filter provided at the bottom of the reaction vessel.

The results obtained are shown in Table V.

Amount of catalyst.

Weight pio / cnt

Polymer

1.0

3.0

5.0

10.0

Table V Carboxyl group number.
Equivalents 10 "g Melting point
(C) Hue of
Polymers ? olycondensation
time in vacuum
(Sid.) _ _
Intrinsic viscosity 31.0
26.3
18.8
14.1 259.5
261.0
260.5
260.0 very light
Yellowing
colorless
colorless
colorless 4-7,
3
^1/2 0.67
0.65
0.69
0.68

Example 6

The autoclave according to Example 1 was 90 parts Dimethyl terephthalate, 10 parts of dimethyl isophthalate, 70 parts of ethylene glycol, 0.015 parts of zinc acetate and 0.02 part of triphenyl phosphite charged. Be; the same conditions as in Example 4 was now a Ester interchange reaction carried out. In this case, the ester exchange calculated from that which was distilled off was Amount of methanol, 97%.

The band pieces made of metallic titanium, the i
Example 5 were used in the
the quantities given in Table VI for the esters
exchange reaction product added. At the gl
Chen conditions as in Example 4 was a pole
condensation reaction carried out. In table
are the analytical data for the obtained Po
merschnitzei put together.

13th 1 905 188 Carrnml- Ij i4 Tone of the PnU kidney Table Vl easily gel Ί
colorless
colorless ^K: 'ni-nuc " ^r ' l'ohkondcn ,, - 2 <SX
19.0
12.1 light yellow green catalyst prozcnl
Polymer tiouvc.it im
V ;, _r iiuni
(SkI ( lim lii:. "- 25.3 Melting point
'" Metallic titanium 1.0
5.0
! 0.0 5 ¹ :
2- '. 0.64
0.62
0.65 240.5
241.0
241.0 Antimony trioxide 0.03 ^4th 0.66 240.5

Example 7

Sponge-shaped titanium blocks were crushed into a powder. This was sifted and put in 4 particle size classes divided: Less than 100 μ; 100 to 200 µ; 200 to 500 μ and larger than 500 μ. The ester leaching reaction product prepared according to Example 4 each powder of the classes described above was added. Then the Polycondensation reaction carried out. The polymer obtained was shaped into chips and dried and spun into threads with 60 den. These became four times the original length stretched and wound on a weft spool. The drawn thread was-; in the one described below Device examined for the number of yarn knots.

Two small lightweight rollers made of stainless steel were previously run through one pre-selected contact pressure brought into contact so that they formed a gap. The one of Rolling was rotated at a fixed position. The other could while moving along the vertical turned to the surface of the nip of the two rollers, can be shifted slightly. When passing through of a thread between the two rollers would be the position of the second roller if the thread was irregular Buttons had moved. This shift is due to the variation in the diameter of the thread when the buttons run through the nip. This variation was measured by a voltmeter recorded. This made it possible to determine the number of buttons in the thread.

It was found that when using titanium particles with less than 100 μ the number of irregular buttons of the polyester thread 135 / 1000Om fraud. The corresponding number for a particle size of ICO was up to 200 μ. 28; at 200 "to 500 μ 11 and for particle sizes above 500 μ 3.

Example 8

100 parts of dimethyl terephthalate. 64 parts of ethylene glycol, 0.015 part of calcium acetate and 0.035 part of triphenyl phosphite were placed in a reaction vessel given. The resulting mixture was heated to 170.degree. The temperature was increased from 170 to 230 ° C. over 3 hours. The reaction was at this Temperature continued for 2 hours with stirring to carry out the ester interchange reaction. The ester exchange was, calculated from the amount of methanol distilled off, 97.8%.

This ester interchange reaction product was transferred to a second reaction vessel through a Tube was connected to the first reaction vessel. The polycondensation was then carried out.

In the polycondensation reaction vessel was the Inner surface of the autoclave made of stainless steel by explosion welding with a plate made of pure metallic titanium. The stirrer consisted of a round bar and a plate made of pure metallic titanium.

In this case the calculated ratio of the polymer to the titanium surface was 1.14 g of polymer cm ^{2 of} titanium surface.

The reaction temperature was 280 ° C. and the stirring speed was 60 rpm. The pressure was reduced to 0.3 mm Hg in 2 hours. In these conditions, the reaction was 4 '/ continued ₂ hours, and then stopped. The extruded polymer had an intrinsic viscosity of 0.64. a number of carboxyl groups of 23.5 and a melting point of 262. S ⁿ C. The polymer obtained was completely colorless.

This is done by polycondensation in a stainless steel autoclave in the presence of 0.04% antimony oxide Control polymer obtained was colored dark yellow green.

The hue of the polymer obtained in this example was very much superior to that of the control polymer. In particular, this variation should in which both polymers split into chips.

thoroughly dried and then transferred to test tubes and ^{crhi'zt under nitrogen gas from atmospheric pressure to 280 c} C for 2 hours, must be observed. The polymer obtained when using antimony trioxide was considerably yellow in color after heating. The intrinsic viscosity had been reduced from 0.66 to 0.54. The number of carboxyl groups had been increased from 19.8 to 32 4. In contrast, in the case of the polymer obtained according to the invention, the intrinsic viscosity was only slightly reduced from 0.64 to 0.61. The number of carboxyl groups varied from 23.5 to 25.8. Finally, the polymer obtained was practical

colorless. ". . , _

Example 9

In a device for continuous polycondensation, which consists of a horizontal cylindrical! Reaction vessel consisted of metallic titanium to the result with a set screw for stirring and order of the polymer was provided, was the ester exchange reaction product of Example 8 gegeber The reaction vessel was heated to 290 ⁰ C. The gas in the reaction vessel was drawn off in order to generate a vacuum, and the screws were turned one turn. The feed rate d <ester interchange reaction product and the rate of decrease of the polymer were adjusted so that the residence time was 8 hours. The polymer obtained was converted into a «

I 905188

The string is deformed, cooled and then cut into chips.

The polymer had an intrinsic viscosity of 0.60 and an alkyl group number of 19.2. It was colorless. The polymer possessed after the heat test according to Example S a viscosity of 0.57 and a number of carboxyl groups of 23.4. It was colorless and possessed excellent heat resistance.

Example 10

100 parts of dimethyl terephthalate, 65 parts of ethylene glycol, 0.02 part of zinc acetate and 0.03 part of triphenyl phosphite were placed in a glass reactor equipped with a stirrer. The resulting mixture was heated under a nitrogen gas atmosphere to carry out the ester interchange reaction. The temperature was increased from 170 ° C. to 230 ° C. over the course of 7 hours in order to distill off the methanol. The ester exchange reaction was stopped. The ester exchange reaction was calculated from the amount of methanol distilled off to be 98.0%. A certain amount of the ester exchange reaction product obtained was then placed in a cylindrical glass reaction vessel The blade of the stirrer was made of a titanium alloy plate in which the ratio of titanium to nickel was 80:20, and a large number of pores 4 mm in diameter were drilled in the plate The whole was melted under nitrogen gas at 230 "C, whereupon the temperature was raised to 280 C with stirring. Thereafter the pressure was within an hour to 0.35 mm Hg ve ^r Ringert. In this state, the reaction was continued in vacuo. After 3 "V ₄ hours was completed the Polykondensalionsreaktion. The resulting polymer was extruded from a lower portion of the Reaktionsgelaßes under nitrogen pressure, to obtain samples. The polymer was virtually colorless and transparent and had an intrinsic viscosity [" /] of 0, 71 and a carboxyl group number of 25.7 and a melting point of 260.5 ° C.

Comparative example

In an autoclave equipped with a stirrer and a fractionating column, 580 g of dimethyl terephthalate (hereinafter abbreviated as DMT), 300 cm ^{3 of} ethylene glycol and 0.6 g of potassium acetate were placed. The resulting mixture was heated under Einleileitung of gaseous nitrogen at 170 ° C and then in the course "on 7 hours by a Ge sch windiness of 10 ⁰ C per hour to 240 C further heated. After the temperature reached 240 ° C , the heating was stopped. During de ·. With heating, the methanol released from the reaction system was distilled off by the fractionating column.

200 mg of antimony trioxide were then added to the ester interchange reaction product obtained. This amount corresponds to that of Example 3 of French Patent 1,509,306, as well as with metallic titanium in various shapes and quantities. The individual quantities are taken from the table VN out. Then the polycondensation reaction at an internal temperature of the autoclave of 275 C and under a pressure of 0.2 mm Hg

K> carried out over a period of 3V ₂ hours, whereby the results shown in Table VIl were obtained. In experiments No. 3 and 4, after the end of the polycondensation reaction, metallic titanium was removed by passing the polymer through a filter arranged at the bottom of the autoclave.

"" " Metallic tilane Tabel VII Ligcnscliaftcn des Polymers I Cl Fiirblonun colorless / ujicyebenc Vcr- 1 ilanmenue number of 260 colorless colorless vicli Fine particles (average Weight lljilriuyl-
üruppen Melting point No. liche particle size: 2.7 a) percent
DMT Intnnsic
Vis.Mtat equiv 10 "» 1 261 colorless the same 23.5 1 0.71 260 Coarse particles (middle part 20.3 2 Chen size: 100 u 3 mm) 0.64 259 Pearls (thickness: 0.3 to 0.5 mm. 19.2 3 Width: 4mm. Not long 2.9 mg 0.67 longer than 5 mm) (0.0005%) 19.7 VIII 4th 1.5 nuz 0.66 (0.00026%) 0.58 a. Tabel To the (0.1%) 1.74 g (0.3%) Comparison was the same working method under <

Use the following polymerization catalysts A and B carried out.

Catalyst A

There was only antimony trioxide in an amount of 200 mg used.

Catalyst B

There were 200 mg of antimony trioxide and titanium hydroxide in an amount of 1.5 mg. calculated as metallic titanium is used.

The properties of the polymers obtained are summarized in Table VIII:

Inlrinsic Λ11 / ΛΙ1Ι the Enamel KaIa- Viscosilate Carboxyl Point ysalor groups (Λιμιίν. (Cl 0.59 Kl "gl 261 A. 0.61 18.3 262 B. 18.7

l'arblon

light yellow
light yellow

From the above experiments it can be seen that by using the procedure of the invention Polymers with significantly better properties can be obtained.

Claims (3)

Patent claims: 1. A process for the production of polyalkylene terephthalates and modified polyesters which consist of at least 75 mol percent of a polyalkylene terephthalate and up to 25 mol percent of units which are formed from at least one other ester-forming component, namely an aliphatic diol, a polyethylene ι ο glycol, a Derive aromatic diol, an alicyclic diol, an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid or an acyclic dicarboxylic acid, marked thereby by polycondensation of bis (hydroxyalkyl) terephthalate, optionally in a mixture with less than 25 mol percent of the further component, in the presence of a metal catalyst "that titanium is used as a metal catalyst. 2. The method according to claim 1, characterized in that the metallic titanium in fcinvertciUer Mold used with average particle sizes less than 100μ. 3. The method according to claim 1 or 2, characterized in that at least part of the Reaction vessel or accessories that come with the Reaction mixture come into contact, made of metallic titanium or a mainly metallic Titanium existing alloy are made.