GB1592684A

GB1592684A - Process for removing impurities from textile material

Info

Publication number: GB1592684A
Application number: GB5042477A
Authority: GB
Original assignee: Bruckner Apparatebau Michelstadt GmbH; Brueckner Apparatebau GmbH
Current assignee: Bruckner Apparatebau Michelstadt GmbH; Brueckner Apparatebau GmbH
Priority date: 1976-12-13
Filing date: 1977-12-02
Publication date: 1981-07-08
Also published as: JPS5374193A; ES464963A1; IT1113815B; JPS5822582B2

Description

(54) A PROCESS FOR REMOVING IMPURITIES FROM TEXTILE MATERIAL (71) We, BRUCKNER APPARATEBAU GmbH, of 30 Werner-von-Siemens-Strasse, 6122 Erbach (Odenw.), Germany, a Company organised under the laws of the German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- This invention relates to a process for removing polymeric impurities or other water soluble impurities or impurities rendered degradeable in water by the use of additives (all hereinafter referred to as "water carried contaminants") from textile material, in which aqueous liquid is applied to the textile material and is subsequently expelled therefrom by application of an organic solvent and is an improvement in, or modification of, the invention described in our Patent No.

1493972 to which reference is made.

In one process of this type, the aqueous liquid remains in the liquid phase throughout the entire process. With the expulsion of the aqueous liquid by the organic solvent, the water carried contaminants are also satisfactorily removed from the textile material.

The object of the present invention is to further develop a process of this type to the extent that water carried contaminants (for example impurities such as these are present in particular in size and in dye-thickening agents) can be removed satisfactorily and particularly inexpensively from textile material.

According to the invention there is provided a process for removing water carried contaminants (as hereinbefore defined) from textile material, comprising applying an aqueous liquid to the material in a witting zone followed by exposing the wetted material wetted material to the action of saturated steam in a steaming zone, the wetted and steamed material being subsequently passed to a treatment zone in which water with any contaminants carried thereby is expelled from the material by the application of an organic liquid solvent immiscible with water and having a greater specific gravity than water.

It has been found that the dissolution or degradation of polymeric or other impurities present in textile material not only takes a certain time, but can also be very effectively assisted by a steaming process, i.e. by the action of saturated steam. The residence time of the textile material in the steaming zone may amount to between 10 seconds and 10 minutes, depending upon the nature of the textile material and the type and quantity of contaminants present in it.

In general, a steaming time of from 1 to 3 minutes will be optimal.

The use of saturated steam in the steaming zone is particularly advisable because evaporation of the water previously applied to the textile material is prevented in this way.

Where the contaminants to be removed from the textile material are substances which are intended to be reused (as is the case in particular with the removal of size from textile material), a further development of the process according to the invention has proved to be of particular advantage. In cases such as these, it is of course desirable to obtain the size removed from the textile material in the form of an aqueous solution with the highest possible concentration because it is only in this form that the size solution can be reused without any need for additional thickening.Accordingly, in one embodiment of the process according to the invention, a highly concentrated, conveniently reuseable size solution is obtained whilst, at the same time, the size is completely removed from the textile material by subjecting the textile material to a further treatment with water after it has passed through the steaming zone, the concentrated size solution which accumulates and the dilute aqueous size solution which remains on the textile material subsequently being displaced therefrom by the action of the organic solvent.

The aqueous size solution displaced from the textile material by the action of the organic solvent (in contrast to the con centrated size solution previously run off, this size solution has a relatively low concentration) may with advantage be returned to a first stage of the process and used there as the first aqueous liquid for treating the textile material (i.e. for prewetting the textile material).

Advantageous embodiments of the process according to the invention are now described in detail in conjunction with the accompanying drawings.

In the drawings, Figures 1 to 3 each diagrammatically illustrate one example of an installation for carrying out a process according to the invention.

The installation shown in Figure 1 is used for removing water-soluble polymers from a web 1 of textile material. This web 1 initially passes through a wetting zone in the form of a waterbath 2 which may optionally contain a wetting agent. After passing through squeezing rollers 3, the web 1 enters a steaming zone which, in the embodiment illustrated, is in the form of a roll steamer 4. However, it is also possible to use numerous other types of steaming zone (for example rotor bar steamers, pilgrim step steamers, etc.). The only important factor is that the web 1 should not be deposited in folds in the steamer. The steamer 4 is filled with saturated steam.

After leaving the steamer 4, the web 1 enters a treatment zone having a chamber 5 in which a liquid organic solvent which is immiscible with and has a greater specific gravity than water is sprayed onto the web 1 through nozzles 6, as a result of which the water present in the web 1, together with the polymeric impurities dissolved therein, is expelled from the web 1. The two immiscible liquids then enter a separator 7 in which the two liquids are separated simply on the basis of the difference in their specific gravities.

The heavier organic solvent is run off as the lower end at 8, whilst the much lighter aqueous solution of the polymeric impurities for example a size solution) is run off at 9 and optionally reused.

The web 1 thus freed from the polymeric impurities then passes through a drying chamber 10 in which it is dried for example by means of an organic solvent.

As already mentioned, the water-soluble polymer (for example the water-soluble size) is effectively swollen and almost completely dissolved in the time taken by the web 1 to pass through the steamer 4 where it is exposed to the action of the saturated steam, so that these contaminants are subsequently removed almost completely from the web during the mechanical displacement of the water from the web 1 by the organic solvent.

Figure 2 shows a modification of the installation illustrated in Figure 1 which may be used for example for removing impurities which, although insoluble in water, can be degraded enzymatically or by oxidation (such as starch size). In this case, the waterbath 2 contains additives suitable for degrading the impurities (for example enzymes or peroxides) In this embodiment, the steamer 4 is provided with two substantially U-shaped dwell tanks 4a, 4b. For the rest, this installation also contains a chamber 5 for spraying on organic solvent as previously referred to, a separator 7 for separating the two liquids of different specific gravity and a drying chamber 10.

The basic function of this installation corresponds to that of the previously described embodiment.

Figure 3 shows another variant of an installation suitable for carrying out the process according to the invention. This installation additionally performs the particular function of producing a particularly concentrated solution of the impurities in the first liquid (for example a particularly concentrated size solution) for the purposes of reuse.

The web 1 initially passes through a wetting zone bath 21, filled with aqueous liquid, in this case size solution (run off at 9 from the separator 10) rather than with fresh water.

After passing through squeezing rollers 3, the web 1 enters the steamer 4 filled with saturated steam and is then delivered to an intermediate treatment zone 11 in which it is further treated with water. In the embodiment illustrated, the intermediate treatment zone 11 consists of two stages 1 la and 1 ib, fresh water being delivered at 12 to the second stage 1 lb, whilst the concentrated size solution formed in the intermediate treatment zone 11 by substantial removal of the impurities from the web 1 is drawn from the stage lla at 13. In the intermediate treatment zone 11, therefore, the impurities (for example size) present in the web 1 are substantially removed in several stages on the countercurrent princitle.In order to promote the removal of these impurities in the intermediate treatment zone 11, squeezing rollers 14, 15 are provided between or after the individual stages.

The web 1 then enters the chamber 5 in which the now highly dilute aqueous size solution which is still present in the web 1 is mechanically displaced by spraying on organic solvent. After separation in the separator 7, this aqueous solution with a relatively low size concentration is returned to the bath 21 where is it used for prewetting the web 1. The particular advantage of the process carried out by the installation shown in Fig. 3 is that the concentrated size solution run off at 13 from the intermediate treatment zone 11 can be reused without any need for additional thickening. Another advantage is that the considerable dilution of the aqueous size solution present in the web 1 produced by the intermediate treatment zone 11 considerably facilitates its removal by the organic solvent in the chamber 5.

This is because, since some of the polymeric impurities are highly viscous and a high viscosity prevents the "washing out", i.e.

the mechanical displacement of this viscous liquid from the web 1, a considerable improvement in this washing-out effect is obtained by the previous dilution of the aqueous solution present in the web 1.

In some cases, it can be of advantage to apply the water and/or other aqueous liquid at elevated temperature in order to improve the dissolution or degradation of the polymeric impurities present in the textile material.

EXAMPLE 1 A woven fabric of cotton/polyester (55/45) weighing 140 g/m2, which is provided with 6 % of an acrylate size, is treated at a speed of 60 metres per minute. To this end, 100 % of an aqueous liquor containing 1 gil of wettng agent is, padded on at the squeezing rollers.

The fabric is introduced into the steaming zone where it remains in the saturated steam for 30 seconds on account of the length of the steaming zone. The fabric is then introduced into the treatment zone where the size solution is washed out by the organic solvent.

The solvent adhering to the fabric is then dried off with hot air. The temperature of the liquor at the squeezing rollers is 20"C for example.

EXAMPLE 2 A woven fabric of polyester/cotton (70/30) weighing 220 g/m2, to which 6% of a polyvinyl alcohol size has been applied, is passed through the installation at a speed of 30 metres per minute. 120% of an aqueous liquor are padded on the squeezing rollers.

In addition to 1 g/l of wetting agent, the liquor contains 50 g/l of thiourea. The fabric is introduced into the steaming zone where it remains for 60 seconds on account of the length of the steaming zone. The fabric is then introduced into the treatment zone without significant cooling and the size solution washed out. The temperature of the liquor at the squeezing rollers is 80"C for example.

EXAMPLE 3 The same fabric as in Example 2 is treated in the same way with the following modifications: from the steaming zone, the fabic enters an intermediate treatment zone having a water washing compartment in which the countercurrent is regulated in such a way that the fabric leaves the installation with a size content of 3 %. The temperature of the liquor in the aqueous washing compartment is above 80"C. The fabric thus treated, which contains from 80 to 120% of a 3 % size solution, is introduced into the solvent zone without significant cooling.

EXAMPLE 4 A 100% cotton fabric weighing 170 g/mS is provided with 18% of starch size. The fabric is passed through the installation at 50 metres per minute. 3 g/l of an enzyme are applied at the Foulard squeezing rollers, the enzyme only being activated under the conditions prevailing in the steaming zone. In addition, the recipe contains a 1 g/l of wetting agent and 5 g/l of sodium chloride. The fabric is left in the steaming zone for 3 minutes; in this time. the starch is enzymatically degraded. The fabric thus treated is then introduced into the solvent zone where the size is washed out. The solvent present in the fabric is dried off in a drying zone.

EXAMPLE 5 A woven fabric of textured polyester filaments in the longitudinal and transverse direction contains 10% of acrylate size and has a weight of 200 g/m2. The textile material is passed through the installation at 30 metres per minute. An aqueous liquor containing 1 g/l of wetting agent is applied at the Foulard squeezing rollers. The fabric remains in the steaming zone for about 3 minutes and is moved back and forth therein. This avoids the formation of transverse folds and initiates shrin = kage. The textile fabric is then introduced into the solvent zone where the size solution is washed out.

WHAT WE CLAIM IS: 1. A process for removing water carried contaminants (as hereinbefore defined) from textile material, comprising applying an aqueous liquid to the material in a wetting zone followed by exposing the wetted material to the action of saturated steam in a steaming zone, the wetted and steamed material being subsequently passed to a treatment zone in which water with any contaminants carried thereby is expelled from the material by the application of an organic liquid solvant immiscible with water and having a greater specific gravity than water.

2. A process as in Claim 1 wherein the residence time of the material in the steaming zone is between 10 seconds and 10 minutes.

3. A process as in Claim 2 wherein said residence time is between 1 minute and 3 minutes.

4. A process as in Claim 1, 2 or 3 for removing size from the material, wherein, after passing through the steaming zone, the material is subjected to treatment with water in an intermediate treatment zone, concentrated size solution which accumulates from said treatment with water being run off and dilute aqueous size solution remaining

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. zone 11 considerably facilitates its removal by the organic solvent in the chamber 5. This is because, since some of the polymeric impurities are highly viscous and a high viscosity prevents the "washing out", i.e. the mechanical displacement of this viscous liquid from the web 1, a considerable improvement in this washing-out effect is obtained by the previous dilution of the aqueous solution present in the web 1. In some cases, it can be of advantage to apply the water and/or other aqueous liquid at elevated temperature in order to improve the dissolution or degradation of the polymeric impurities present in the textile material. EXAMPLE 1 A woven fabric of cotton/polyester (55/45) weighing 140 g/m2, which is provided with 6 % of an acrylate size, is treated at a speed of 60 metres per minute. To this end, 100 % of an aqueous liquor containing 1 gil of wettng agent is, padded on at the squeezing rollers. The fabric is introduced into the steaming zone where it remains in the saturated steam for 30 seconds on account of the length of the steaming zone. The fabric is then introduced into the treatment zone where the size solution is washed out by the organic solvent. The solvent adhering to the fabric is then dried off with hot air. The temperature of the liquor at the squeezing rollers is 20"C for example. EXAMPLE 2 A woven fabric of polyester/cotton (70/30) weighing 220 g/m2, to which 6% of a polyvinyl alcohol size has been applied, is passed through the installation at a speed of 30 metres per minute. 120% of an aqueous liquor are padded on the squeezing rollers. In addition to 1 g/l of wetting agent, the liquor contains 50 g/l of thiourea. The fabric is introduced into the steaming zone where it remains for 60 seconds on account of the length of the steaming zone. The fabric is then introduced into the treatment zone without significant cooling and the size solution washed out. The temperature of the liquor at the squeezing rollers is 80"C for example. EXAMPLE 3 The same fabric as in Example 2 is treated in the same way with the following modifications: from the steaming zone, the fabic enters an intermediate treatment zone having a water washing compartment in which the countercurrent is regulated in such a way that the fabric leaves the installation with a size content of 3 %. The temperature of the liquor in the aqueous washing compartment is above 80"C. The fabric thus treated, which contains from 80 to 120% of a 3 % size solution, is introduced into the solvent zone without significant cooling. EXAMPLE 4 A 100% cotton fabric weighing 170 g/mS is provided with 18% of starch size. The fabric is passed through the installation at 50 metres per minute. 3 g/l of an enzyme are applied at the Foulard squeezing rollers, the enzyme only being activated under the conditions prevailing in the steaming zone. In addition, the recipe contains a 1 g/l of wetting agent and 5 g/l of sodium chloride. The fabric is left in the steaming zone for 3 minutes; in this time. the starch is enzymatically degraded. The fabric thus treated is then introduced into the solvent zone where the size is washed out. The solvent present in the fabric is dried off in a drying zone. EXAMPLE 5 A woven fabric of textured polyester filaments in the longitudinal and transverse direction contains 10% of acrylate size and has a weight of 200 g/m2. The textile material is passed through the installation at 30 metres per minute. An aqueous liquor containing 1 g/l of wetting agent is applied at the Foulard squeezing rollers. The fabric remains in the steaming zone for about 3 minutes and is moved back and forth therein. This avoids the formation of transverse folds and initiates shrin = kage. The textile fabric is then introduced into the solvent zone where the size solution is washed out. WHAT WE CLAIM IS:

1. A process for removing water carried contaminants (as hereinbefore defined) from textile material, comprising applying an aqueous liquid to the material in a wetting zone followed by exposing the wetted material to the action of saturated steam in a steaming zone, the wetted and steamed material being subsequently passed to a treatment zone in which water with any contaminants carried thereby is expelled from the material by the application of an organic liquid solvant immiscible with water and having a greater specific gravity than water.

on the textile material being subsequently displaced therefrom by the action of the organic solvent in the treatment zone.

5. A process as in Claim 4, wherein the aqueous size solution displaced from the textile material by the action of the organic solvent is returned to the wetting zone where it is applied as the aqueous liquid to the textile material.

6. A process as in Claim 4 or 5 wherein said treatment with water in the intermediate treatment zone is effected in several stages, preferably on the counter-current principle'

7. A process as claimed in Claim 6, wherein the textile material passes in web form through squeezing roller and/or extraction units between successive stages of the treatment with water in the intermediate treatment zone.

8. A process as in Claim 1, 2 or 3 wherein the aqueous liquid is applied at elevated temperature.

9. A process as in claim 4, 5, 6 or 7 wherein the water is applied at elevated temperature in the intermediate treatment zone.

10. A process as in any one preceding claim when used in the treatment of textile material consisting of polyester, polyamide, or other textured filaments.

11. A process as in any one of claims 1 to 9 when used in the desizing of cotton-based textile material treated with starch size.

12. A process as in Claim 11 so far as dependent upon claim 7 wherein enzymes sensitive to high temperatures are applied to the textile material in the vicinity of the squeezing rollers.

13. A process as in any one of claims 1 to 9 when used in the desizing of textile material of polyester/cotton.

14. A process as in Claim 13 when used in the removal of polyvinyl alcohol size.

15. A process as in Claim 14 wherein the aqueous liquid contains from 5 to 10% of urea or thiourea.

16. A process as in Claim 13 when used in the removal of acrylate size.

17. A process as in Claim 16 so far as dependent upon claim 7 wherein an alkali is added to a treatment bath preceding the squeezing rollers.

18. A process as in Claim 13 when used in the removal of size of the carboxylated cellulose and carboxylated starch type.

19. A process as in any one of claims 1 to 9 when used in the desizing of woven fabric of cellulose acetate-polyacrylonitrile and mixtures thereof with natural fibres.

20. A process as in any one of claims 1 to 9 when used in the desizing of wool and mixtures thereof with synthetic fibres.

21. A process as in any one of claims 1 to 9 when used in the removal of polymeric contaminants from glass fibre cloth.

22. A process as in claim 11 wherein the aqueous liquor contains hydrogen peroxide or other oxidising agents.

23. A process as in Claim 1, 2 or 3 when used in the removal of polymeric dye thickeners from the textile material.

24. A process for removing water carried contaminants from textile material substantially as hereinbefore described with reference to Figure 1, 2 or 3 of the accompanying drawings; or in any one of Examples 1 to 5.