CS232936B1 - A method for the continuous preparation of modified pciytorial fibers - Google Patents

Abstract

Modified polyester based on ethylene glycol terephthalate for spinning is prepared continuously by feeding the saturated product of the combined esterification of isophthalic acid and the anoalkaline salt of 5-sulfophthalic acid of ethylene glycol into the low molecular weight section of the production line for the continuous preparation of polyester fibers. The flow rate of the saturated product, in which the proportion of both components is constant, is the flow rate of the terephthalic component at the inlet of the co-polymers to the production line, is adjustable.

Description

The invention solves the method of continuous preparation of polyester fibers by combined modification with isophthalic acid derivatives.

Until now, industrial polyesters of polyethylene terephthalate type have been produced in a continuous manner with a simple modification, for example according to Art. AO 181 508 by adding dllycol ester of the monosodium salt of sulfoisophthelic acid to the early stages of proises. isophthalic acid modified polyesters are produced in batches and are fed to the proees with the basic raw materials dimethyl terephthalate and ethylene glycol, in dimethylisophthalate.

V ča. AO 173 918 describes a process for a simple or combined modification of polyethylene terephthalate-type polyester fibers by adding and mixing the melting of polymeric and modifiable concentrates into the base polymer prior to spinning. This process has, besides a number of advantages, in particular the fact that the course of the interchangeable and polycondensation of the basic polycondensate is not influenced by the modifiers, and that the change of assortment on the continuous line is associated with a small outage of non-standard transition material. The disadvantages of the concentrate process, especially in the continuous production of polyester fibers, are the considerable complexity and cost of preparing and adding the concentrate melt to the mainstream melt. The granules of the concentrates need to be prepared in large quantities on a separate set-up, perfectly perfected, which is particularly demanding with respect to tackiness and susceptibility to hydrolytic and thermal degradation, especially in the case of modifying concentrates. After cooling, it is necessary to melt them again, accurately dose and mix them and with mainstream. The whole process becomes energy-intensive 1.

The drawbacks of the known methods of the combined modification of polyester fibers are eliminated by the process according to the invention, which consists in preparing a two-component solution or melting agent of the modifying agent as a mixed product and feeding it to the low molecular weight continuous production of the polyoater. The ratio of isophthalic and 5-sulfolaphthalic components in the mowed product is constant. The content of free ethylene glycol and the temperature of the mainstream and the mixed product are not too roadile. The molar ratio of the laoftal component to the mixed product to the terephthal component of the mainstream and sets the dosing elements in the range of 0.006 to 0.25.

An object of the present invention is a process for the continuous preparation of modified polyester fibers based on ethylene glycol terephthalate by exchange esterification of palletyl terephthalate or esterification of terephthylic acid with atylanglycolam, polycondensation and spinning, which comprises combined modification of polyester with isophthalic acid % of a component of lysophthalic acid and 5-sulfolaphthalic acid glycerol containing 0.5 to 60 wt. % of free ethylene glycol, which is continuously fed to a prepelycondensate containing from 0.5% to 30% by weight. of free ethylene glycol, the temperature difference of the wash currents being 0 to 130 K.

The modified fibers produced by the combined modification of the present invention excel in a dyeable dyeing and a reduced tendency to waterproofing, can be produced in a non-refractory finish. Advantages include the fact that the ratio of the deflocculation components is constant and that the dosing of the backed product is reliable and easy to carry out due to its relatively low viscosity. Thus, a defined composition of the copolyester produced and its properties and properties are achieved. The similarity of the two metered streams given by the excessively cast temperature and the free ethylene glycol content makes it possible to perform mixing without fluctuating the technological parameters of the main line. The process according to the invention is simple, it does not require the preparation of the melted granular concentrate as previously described concentrate process, which is technologically and energy-intensive, with good overall, qualitative and economic results.

The process of the invention combines the advantages of the concentrate process with the dosing of the modifying components prior to spinning, with the method wherein the modifying components are introduced into the raw materials on the main line, and can be combined with these methods to produce fibers modified with a number of additives.

The preparation of copolester fibers according to the invention is illustrated in the following examples.

He did

Into the reactor with the passage, the heating mantle and the separating column with a controllable return flow were not weighed:

kg of 5-sulfoisophthalic acid, monosodium aol 200 kg of lsophthalic acid * I, 7 kg of zinc acetate

0.5 kg of sodium chloride measured!

0.760 · ³ ethylsilyl glycol.

At 198 ° C, the batch was reacted for 6 hours, 55 d · ^{3 of} distillate containing 0.3% ethylene glycol and the remainder water were removed from the top of the column.

The diglycol ester solution obtained was dosed at a rate of 143.6 kg / h by a piston pump over the last re-esterification step of a continuous-working production line and direct spinning of polyester fibers having a throughput of 440 kg / h. The product temperature at the inlet point was 253 ° C and the free ethylene glycol content was 8.3% ha. Subsequent copolymerization took place in three stages, the final temperature being 284 ° C and a pressure of 500 Pa. The copolymer melt was directly spun and, after elongation, a modified polyester fiber with improved dyeability and reduced tendency to chip.

Example 2

The reactor as in Example 1 was weighed:

kg of non-sodium aol of 5-sulfolsophthalic acid

210 kg of lsophthalic acid 1.6 kg of manganese acetate 0.35 kg of sodium chloride and measured:

0.740% ethylene glycol.

At a temperature of 198 ° C, the batch reacted 53.7 da ^{3 of the} distillate of water containing 0.2% ethylene glycol from the top of the column after 5.5 hours.

The diglycol ester solution obtained was metered into the first polycondensation stage of a direct spinning polyester fiber production line at a rate of 476 kg / h at a rate of 15 > 2 kg / h by a piston pump. The product temperature at the inlet point was 272 ° C and the free ethylene glycol content was 0.3%. The pressure in the first polycondensation stage was 8 kPa. The technological parameters at the other nodes were the same as in Example 1.

Example 3

Ssterlfikaee Bonosodium salt of 5-sulfolic acid with ethyl glycol was carried out in a barthy procedure on the apparatus described in Example 1. 700 kg of ethylene glycol preheated to 20 ° C were charged to the reactor and 250 kg of monosodium salt were introduced with stirring. of 5-sulfoisophthalic acid, 2 kg of ananganic acid and 0.5 kg of sodium chloride. Ssterlfikaee was completed after the Bastion hours at a final temperature of 200 ° C. The reaction water was removed from the top of the column. The reaction chamber was continuously fed from a reservoir to a piston pump into a first chamber of a continuous seven-chamber stirred cascade, equipped with a long packed column, at a rate of 60 kg / h. Ethylene glycol at a rate of 50 kg / h and a melt of dimethyl isophthalate at a rate of 80 kg / h were introduced into the first chamber by a piston pump. The ester exchange was carried out at normal pressure at a gradually increasing temperature of 160 ° C to 250 ° C and an average residence time of 5 hours.

The ester exchange product was continuously fed via a control valve into the piping upstream of the first polycondensation reactor of a 24-hour direct spinning polyester fiber production line with a power of 870 kg / h of modified polyethylene terephthalate melt. After elongation, high-quality modified polyester fibers have been obtained with improved dyeability and reduced tendency to pilling.

Claims (2)

t. A process for the continuous preparation of modified polyester fibers based on ethylene glycol terephthalate by interchangeable esterification of dimethyl terephthalate or esterification of tersphthalic acid with ethylene glycol. a solution of the modifying components represented by diglycol esters of isophthalic acid and 5-sulfoisophthalic acid containing 0.5% ttf. 60 wt. % of free ethylene glycol, which is continuously fed to prepolycondensate containing 0.5% to 30% by weight of ethylene glycol; free ethylene glycol, the temperature difference of the charged streams being 0 to 130 K. 2. A method according to claim 1, wherein the solar ratio of the 5-sulfolsophenyl units to the isophthyl units in the modifier component is 0 to 1.2.