AU683042B2 - Process for desizing sized textile materials - Google Patents

Abstract

A process for desizing sized textile materials (grey goods) by treating the grey goods with water and by separating the sizing agent solution which adheres to the grey goods is characterized in that the grey goods are heated after being treated with water, before the sizing agent solution which adheres to the grey goods is separated therefrom.

Description

WO 94/18374 PCT/EP94/00265 Process for desizing sized textile material The present invention relates to a process for desizing sized textile material wherein the size is washed off by means of water, the resulting sizing agent solution is separated from the fabric and subsequently reused for sizing as completely as possible.

Sizes are more or less readily water-soluble polymers which are applied to textile threads to render them more hard-wearing and smoother for a processing operation, in particular weaving. After the processing operation, they generally have to be removed again (desizing). According to the state of the art, desizing is carried out by passing the processed (woven), dry, sized textile material (loomstate fabric) through a water bath and then equeezing it off, for example open-width washer, jigger, reel beck, rope washer. Depending on the water solubility of the size, it is advisable in certain circumstances to use higher temperatures and/or surfacthnts and/or enzymes for this. For reasons of economy and environmental protection it is desirable to reuse as high a proportion as possible of the size washed off the fabric. The highly dilute sizing agent solution has to be strengthened reconcentrated) for this. This is generally done by evaporating or ultrafiltering the dilute sizing agent solution. Both methods require a high outlay, one especially in terms of energy, the other in terms of apparatus.

DE-C-2 937 002 describes a process for desizing continuous fabric wherein the size is continuously washed off by means of water, the resulting sizing agent solution is separated from the fabric and subsequently reused for sizing as completely as possible, which is characterized in that the still dry, sized fabric is initially wetted with the sizing agent solution separated off after the wash-off, so that the fabric and the size adhering to it take up water, by swelling and/or solvation, from the sizing agent solution subsequently to 2 be separated off and reused and so increase the concentration thereof and only thereafter is the fabric subjected to the actual wash-off operation. In the process described, thus, the dry, sized textile material (loomstate fabric) is first passed through a sizing agent solution obtained from a previous wash and subsequently squeezed off.

The disadvantage with the process described is the fact that the dry fabric essentially needs to be loaded with the same size as the sizing agent solution used, which is to have water withdrawn from it by the treatment of the dry fabric. Furthermore, only those sizing agents are deemed suitable which have a very low viscosity and which also have a high rate of swelling at room temperature. In this connection, in particular sizing agents based on acrylate are deemed suitable.

As further state of the art there has to be named DE-A-37 03 049, which concerns a process for bleaching and an apparatus for carrying out the process. In the process for bleaching in particular cotton-containing yarns or textile sheet materials, an oxidative bleaching agent is applied to the yarn or sheet material and the so impregnated yarn or sheet material is heated up to release oxidizing constituents from the bleaching agent.

For this, the yarn or sheet material is heated up by irradiation with microwaves of a wavelength between about 1 m and 10' 2 m. The heating facility has an inlet opening and an outlet opening for the yarn or sheet material to be bleached. Within the heating facility there is arranged at least one magnetron for generatiag microwaves, at least one coupling element and at least one hollow guide which extends transversely to the endless cloth.

Object of the present invention is providing a process for desizing sized textile material (loomstate fabric) which makes possible even the use of sizing agents having a higher viscosity and a lower swelling rate.

3 Furthermore, the process shall lead to an improved desizing of the sized textile material.

Surprisingly it has been found that heat treatment of the textile material after passing through the water bath and subsequent squeezing-off of tha sizing agent solution gives a process which meets these requirements.

The invention accordingly provides a process for desizing sized textile material (loomstate fabric) wherein the loomstate fabric is treated with water and the sizing agent solution adhering to the loomstate fabric is separated off, characterized in that the loomstate fabric, after the treatment with water, is heated and subsequently the sizing agent solution adhering to the loomstate fabric is separated off.

The process of the invention will now be more particularly described. As loomstate fabric there are used the prior art textile sheet materials, such as woven material made of polyester, linen and/or cotton, which are loaded with water-soluble size.

Customary water-soluble sizing agents are synthetic and/or (usually modified) natural high polymers, such as glutinous proteins, polymers based on acrylate, carboxymethylcellulose, alginates, polyvinyl alcohol and watersoluble starch products. Preferred sizing agents are polyvinyl alcohol and/or carboxymethylcellulose.

The size add-on on the textile material is detached in the below-described three operations: 1. treating the loomstate fabric with water.

2. heating the water-treated impregnated) loomstate fabric 3. removing the sizing agent solution adhering to the impregnated loomstate fabric.

The treatment of the loomstate fabric with water as per operation No. 1 usually involves wetting the loomstate

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4 fabric with pure water at a temperature within the range from 60 to 100°C. The use of textile auxiliaries, such as surfactants and/or sequestrants, is possible, but generally not desirable.

In this operation, which is also referred to as water impregnation, intimate contact between the liquid phase and the loomstate fabric is advantageous. Suitable for intimate-contact water impregnation are in particular washing units of the roller vat type, in which case the vertical cloth guidance and bulkhead separation is particularly advantageous. It is not necessary in this connection that the washing unit be fully flooded, but the lower rolls have to be immersed at least two thirds in the wash liquor.

Further, it is possible to use modern addition application processes, such as ®Flex-Nip (from KUsters, DE), Booster (from Benninger, CH) and ®Super-Sat (from Babcock, GB).

In the water impregnation, the water pick-up of the loomstate fabric is generally between 60 and 150% by weight, based on the weight of the goods. The water pick-up depends on various factors, such as the nature of the loomstate fabric, the water temperature, the method of application and/or the contact between loomstate fabric and water.

The contact times between water and loomstate fabric in the course of the water impregnation step depend in the main on the time required to wet the fabric completely and evenly and so ensure an adequate water availability for the size add-on to be removed.

At the end of the water impregnation, the water-loaded loomstate fabric is heated (operation No. for which a heating to temperatures between 60 to 140 0 C, preferably between 90 and 130 0 C, is sufficient.

The heating is usually effected by irradiation with microwaves or by treating with steam.

I As regards the heating of the impregnated loomstate fabric with microwaves, the microwaves used preferably have a wavelength between about 1 m and 10 2 m. Owing to the relatively simple ways of controlling the microwaves, which is possible for example through variation of the wavelength or through the energy per unit area, the heating of the thus irradiated loomstate fabric is possible in a particularly simple manner. Nor does this involve such a strong heating of the irradiated loomstate fabric, so that fiber damage cannot ocrcur. The wavelength or frequency used in the particular case and the energy of the wavelength used in the irradiation of the impregnated loomstate fabric depend on the particular impregnated loomstate fabric to be irradiated, i.e. the fiber type, the basis weight and the construction, the particular sizing agent used and the irradiation time.

Preferably the impregnated loomstate fabric is irradiated with microwaves of a wavelength between about 3-10 1 m and about 5.10 2 m. Concerning the heating it has to be noted that the aforementioned, relatively long wavelengths, i.e. those in the metre or centimetre range, bring about a relatively rapid heating to temperatures between 60 and 140*C, preferably 80 to 100 0 C, while shorter wavelengths, i.e. those in the millimetre range and smaller, do not heat the impregnated loomstate material so strongly.

Radiation times between about 20 sec and 2 min, preferably 20 sec to 80 sec, are usually sufficient in the process according to the invention.

The heating apparatus required generally comprises a fully enclosed heating apparatus into which the impregnated loomstate fabric is introduced via an inlet apparatus provided at the heating apparatus. The heating apparatus is further provided with an outlet apparatus which is usually arranged opposite to the inlet opening and serves to guide the impregnated and irradiated loomstate fabric out of the heating apparatus. Within the I heating apparatus there is a unit for generating the microwaves. Such a heating apparatus is described in detail in DE-A-37 03 049.

As mentioned earlier, the heating of the impregnated loomstate fabric can also be effected by treating with steam, for which the temperature is customarily between and 140 0 C. The steam used can be saturated (absolute humidity 100%) or unsaturated and can be used at atmospheric pressure or at a superatmospheric pressure of up to 6 bar. In the case of heating under atmospheric pressure, the temperature of the steam is 60 to about 100 0 C, preferably 80 to 100 0 C, and in the case of heating under superatmospheric pressure the temperature is 100 to 140 0

C.

It has been found that a treatment time with steam over a period of 30 sec to 5 min, preferably 90 to 120 sec, is sufficient. The steamers required for the treatment are known, and preference is given to using atmospheric pressure steamers.

It has been found that heating the impregnated loomstate fabric within the aforementioned temperature range dissolves in the adherent water even sizing agents having a high solubility temperature, poor solvation and a long swelling time.

After heating, the textile material is freed as substantially as possible from adhering sizing agent solution (operation No. The detaching of the sizing agent solution is usually effected with known units such as squeeze rollers, suction drum or suction slit.

After the separation, the residual moisture content of the textile material is about 30 to 60% by weight, based on the weight of the goods.

The sizing agent solution obtained after the separation has a sizing agent content of up to 60%, based on the

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7 amount of sizing agent used. The amount of size separated off is present in only a little water, namely in about to 50% water extract, based on the weight of the textile material. Without further working-up, this size solution can be passed to the sizing room and be admixed there with new size material in order to be supplied to the weaving shed for reuse. The hitherto customary concentrating of the sizing agent solution, for example by evaporation or by ultrafiltration, is not necessary.

The desized textile material is carried off for the customary further processing.

Advantageous with this process, compared with the processes customary according to the state of the art, is that the sizing agent solution obtained after the desizing process can be fully and without losses used in the sizing room for making up new size liquor. After the desizing, a sizing agent solution with up to 60% of the sizing agent originally present on the loomstate fabric is obtained and completely reutilized in the sizing room.

The examples which follow illustrate the process according to the invention.

Example 1 1000 kg of a plain-woven fabric consists of 560 kg of warp thread material and 440 kg of weft thread material.

To weave this fabric, the warp threads are treated with 11% by weight of sizing agent 62 kg), based on the weight of the warp threads. The sizing agent used is a modified polyvinyl alcohol (®Vinarol UF).

After weaving, the loomstate fabric is impregnated with water, so that the water pick-up of the fabric is 100% by weight, based on the weight of the loomstate goods.

Then the fabric is heated in a customary steamer with saturated steam having a temperature of 102 0 °C over a period of 3 minutes.

After leaving the heating apparatus, the woven material is passed through a high-performance squeeze system and 8 the adhering sizing agent solution is squeezed off. The residual moisture content of the woven material is 1000 kg of woven material produce 500 1 of sizing agent solution containing 56 g/l of sizing agent 28 kg). The determination is carried out by means of a refractometer.

This size concentrate is carried off to the sizing room and introduced there into the size box. Heating up and maintaining the temperature of the size liquor by means of steam produces about 120 1 of condensate, so that 620 1 of size liquor are available for sizing. 34 kg of fresh sizing agent are dissolved in this size liquor in order that the sizing agent concentration is again 62 g/l. The size recovery rate is thus This size liquor is used to size 560 kg of new warp thread material, producing 1000 kg of woven material. The woven material is again subjected to the above-described desizing process.

Examples 2 to The procedure is as per Example 1.

Sizing woven 50/50 polyester/cotton with a size add-on of 11% by weight consisting of polyvinyl alcohol/carboxymethylcellulose. 50% by weight of 'the woven material consist of warp material. The woven material is impregnated with water and exposed for 55 seconds to a microwave unit having a heat output of 800 watts/100 cm 2 Thereafter the woven material is squeezed off and the size concentration in the regenerate is determined by means of a refractometer.

Table 1 shows the respective recovery rates

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9- Table 1: Liquor pick -up 81.2% 95.5% 100.8% 106.4% Residual moisture content 33.5% 30.7% 33 .6% 31.8% Size concentration 6.0% 5.0% 3.5% 3.5% Recovery rate 45.8% 51. 8% 37.6% 41.8%

Claims (12)

1. Process for desizing sized textile material (loom- state fabric) wherein the loomstate fabric is treated with water and the sizing agent solution adhering to the loomstate fabri is separated off, characterized in that the loomstate fabric, after the treatment with water, is heated and subsequently the sizing agent solution adhering to the loomstate fabric is separated off.

2. Process according to claim 1, characterized in that the water for treating the loomstate fabric has a temperature within the range from 60 to 100 0 C. 15 3. Process according to claim 1, characterized in that the water pick-up of the loomstate fabric is between 60 and 150% by weight, based on the weight of the loomstate fabric.

4. Process according to claim 1, characterized in that the contact time between loomstate fabric and water is 20 to 200 seconds.

5. Process according to claim 1, characterized in that the heating of the loomstate fabric after the treatment with water is to a 25 temperature between 60 and 140 0 C.

6. Process according to claim 5, wherein the loomstate fabric is heated to a temperature from 90 to 130 0 C.

7. Process according to claim 1, characterized in that the loomstate fabric is heated by microwaves or steam. S 8. Process according to claim 7, characterized in that microwaves vs having a wavelength of 1 to 102, are used. I gl-- ?ANVPDOCSNAL\SPI3CU59140.P1- 3j1/7(

11- 9. Process according to claim 8, wherein said microwaves have a wavelength from 3-10- 1 to 5-10 2 m. Process according to claim 7, characterized in that the steam has a temperature within the range from 60 to 140 0 C. 11. Process according to claim 7, characterized in that the loomstate fabric is heated over a period of 20 seconds to 2 minutes, when microwaves are used.

12. Process according to claim 11 wherein said loomstate fabric is heated over a period from 20 to 80 seconds.

13. Process according to claim 7, characterized in that the loomstate 15 fabric is heated over a period of 30 seconds to 5 minutes when steam is used. eA oo agent solution is separated off by squeezing off.

16. Process according to claim 1, characterized in that up to 60% of 25 the size liquor originally used are removed from the loomstate fabric. DATED this 30th day of July, 1997. HOECHST AG By Its Patent Attorneys DAVIES COLLISON CAVE i HOE 93/F 032 Abstract Process for desizing sized textile material The present invention relates to a process for desizing sized textile material (loomstate fabric) wherein the loomstate fabric is treated with water and the sizing agent solution adhering to the loomstate fabric is separated off, which is characterized in that the loom- state fabric, after the treatment with water, is heated and subsequently the sizing agent solution adhering to the loumstate fabric is separated off. I Ir u INTERNATIONAL SEARCH REPORT Inter nl Applicaton No PCT/EP 94/00265 A. CLASSIFICATION OF SUBJECT MATTER IPC 5 D06L1/14 According to International Patent Classfication (IPC) or to both national classficaton and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) IPC 5 006L Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data bare consulted durng the mtema onal search (name of data base and, where practical, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category Citation of document, with indication, where appropriate, of the relevant p-sages Relevant to claim No. X TEXTILE CHEMISTRY INDUSTRY 1,3-5, vol. 12, no. 4 April 1980 TRIANGLE 11,12 PARK pages 67 C.LIVENGOOD, C.TOMASINO 'How much Energy should it take to remove water soluble Sizes' see page 68 page 69 A DE,A,25 43 815 (BASF) 14 April 1977 1,2,11, 12 see examples 1-2 M Further documents are listed in the continuation of box C. Patent family members ar listed in annex. Special categones of cited documents: Speal categories of cted documentsT ter document published after tln international fling date A document dfing the genral state of the art which is not or pnonty date and not n conflict with the application but WA document defbtng thre of saeof the art which is notpacied to understand the pnnclple or theory underlying the considered to be of particular relevance invention "E earlier document but published on or after the international X' document of particular relevance; the claimed invention filing date cannot be considered novel or cannot be considered to document which may throw doubts on priority cla m(s) or involve an inventive step when the document is taken alone which is cted to establish the publication date of another Y document of particular relevance; the claimed invention citation or other special reason (as specified) cannot be considered to involve an inventive step when the document referring to an oral disclosure, use, exhibition or document is combined with one or more other such docu- other means mcnts, such combination being obvious to a person skilled document published prior to the international filing date but in the art. later than the priority date claimed document member of the same patent family Date of the actual completion of the international search Date of mailing of the international search report June 1994 2 9. 06. 9 4 Name and mailing address of the ISA Authorized officer European Patent Office, P.B. 5818 Patentlaan 2 NL 2280 HV Rijswijk Tel. (+31-70) 340-2040, Tx. 31 651 epo ni, Pfannenstei n, H Fax: (+31-70) 340-3016 Pfannenstein, H Form PCT/ISA/210 (econd ihtet) (July 1992) page 1 of 2 INTERNATIONAL SEARCH REPORT Intler nal ApplicAtion No PCT/EP 94/00265 C.(Continuation) DOCUMENTS CONSIDERED TO BE RELEVANT Category *fCitation of document, with indication, where appropriate, of thc relevant passges Relevant to claim No. A MELLIAND TEXTILBERICHTE1 no. 4 1987 DE pages 270 272 M.KELLOU, C.PIVIDORI, M.ALPHONSUS Entschlichten der wichtigsten Schlichtefamilien auf Polyesterfil1amentgarnen' see tibles 1-3 A EP,A,O 055 975 (CIBA GEIGY) 14 July 1982 1 see example 2 Fonn PCT,'ISA0421 (cotinuation of second thett) (July 1992) page 2 of 2 INTERNATIONAL SEARCH REPORT Information on patent family nicmberv lntcr nal Apvhicauon No IPCT/EP 94/00265 Patent document Publication 1Patent family Publication cited in search report I date Imember(s) I date DE-A-2543815 14-04-77 AT-B- BE-A- CH-A, B FR-A, B GB-A- JP-A- NL-A- SE-A- US-A- 353215 846579 615797 2326531 1561798 52043885 7610697 7610871 4095947 12-11-79

24-03-77

29-02-80 29-04-77 05-03-80 06-04-77 05-04-77 02 -04-77 20-06-78 EP-A-0055975 14-07-82 US-A- 4426203 17-01-84 Formn PC?/ISAJ210 (patent family annex) (MuY 1992) INTERNATIONALER RECHERCHENBERICNT Inter "eks Aktenzlchen PCT/EP 94/00265 A. KLASSIFIZIERUNG DES ANMELDUNGSGI:GENSTANDES IPK 5 D06L1/14 Nach der internatlonalen Patentidlasmuilkaton (IPK) oder nach der nationalen Kiassifikation und der IPK B. RECH-ERCHIERTE GEBIETE Recherclaterter Mindestpriifsloff (Klassflkaonssystcm und lasfikaticnssynibole) IPK 5 D06L Recharchaerte aber nicht zma Mindestpr~fstoff geha6rendc Verdifentlichungen, soweit diese tinter die recherchicrten Gehbiete fallen Wilarcnd der internationaleni Recherche konsultierte elektronische Datenbank (Name der Datenbank und evil. verwendete: Suclabegratfle) C. ALS WESENTLICH ANGESEHENE UNTERLAGEN Kategone* Bezeichanung der Verdfentlchung, soweit erforderlich unter Angabe der in Betlacht kornmenden Teile Betr. Aspriith Nr. X TEXTILE CHEMISTRY INDUSTRY 1,3-5, 3d. 12, Nr. 4 April 1980 TRIANGLE PARK 11,12 Seiten 67 C.LIVENGOOD, C.TOMASINO 'How much Energy should it take to remove water soluble Sizes' siehe Seite 68 Seite 69 A DE,A,25 43 815 (BASF) 14. April 1977 1,2,11, 12 siehe Beispiele 1-2 ~3JWeiterc Ver~ffentlichutngcn sind der Fortiezzung von Feld C zu Scenag'tnfnii Besondere Kategonena von angegebenen Ver~fentllchungen 'T Sp re Verdflcntlichung, die nach demn internationalcna Anmaeldedatumn er~lentichng, ie en ligealeen SandderTechik efineroderdem Priontitsdatumn veriftentiichat worden ist und inut der a Ver Wenchundi e als es ge eesnen an der eiinkdelse Anmaeldung nicht kollidiert, sondemn nur zitmaerstandnss des der ahe nihtam esodes bdetsa aszuehe ~Erfinduing zuigrundeiicgenden Prinzpjs oder der ihar ziagrunrdeiiegenden 11teres Dokument, das jedoch erst am oder nach dean intcraaonalen Theorie angegebeni ist Anmeidedatuma verdifentlicht woIrdefl is W Ver6ffentluchung von besonderer Bedeutung; die beanspruchte Erfindun Verolfentlichung, die geeignet ist, einen Priorititsanspruch zweifeihaft er- kann alicin au'gnd diescr Ver6fenliiciflng njcht als neti oder auif schemnen zu lassen, oder durch die da VerblfenUlichungsdatumn caner erfinderischer Tqtigkcit beruhend belrachtet werden anderena xrn Recherchenbencht &cnannten Verifientlichung belegt werden 'Y Verdflentlichung von besonderer Bedeutussir die beansprucbte ErfindunE soil oder die aus einer-n anderen besonderen Grund angegeben ist (wie kann nicht ala auif erfinderscher TAtigkeut bearuhlend lcrachatet ausgerflart) werden, wensi die Verdffentlichung lnst caner oder mchareren anderen Veroffentlichung, die sich auf emne rnindliche Offenbiarung, Veraffenllichungen dieter Kategorie in Verbinduang gebracht wird und e'.ne Benuizung, eaie Atisstellung oder andere Ma~lnien bealelfl diese Verbinduang fir cinen Fachmann nahecliegend ist Veroffentlichung,die vor dem nternatonalen Ansneldedasm, aber nach .~Verdflentimchung, die Mitglied derselben Pater Ifamilse 1st dema beanspruchaten Priontitsdattiin ver~flentlichat Worden Datumn des AbsclJusses der internationalen Recherche Absenidedatumn des intemnationalen Recherchenber -his Juni 1994 29. 06- 94 Name Laid Postanschrift der Internationale Rechecrchenbehorde Bevollmnichtigter Bediensteter Europaisehes Patrntamt P.13. 5818S Patentlaan 2 NL 2280 H-V Rijswijk Tel. (-i31-70) 340-2040,Mc. 31 651 cso ni,Pane ten H Fa= 31.70) 340-3016 fne s i ,H Faonilm PCT/ISAJ2III (auatt 2) (lull 1992) Seite 1 von 2 INTERNATIONALSR ReCHERCHIENBERICHT Intor nAlck Akctenzcchen PCT/EP 94/00265 C(Fortsmtung) ALS WESENTLICH ANGESEIIENE UNTERLAGEN Kategonec Bczechnung der Veraffentlichung, sowcit crforderlich uinter Angabe der in Becuacht kommcnden Tale B~ev. Anapruch Nr. A MELLIAND TEXTILBERICHTE1 Nr. 4 1987 DE Seiten 270 272 M.KELLOU, C.PIVIDORI, M.ALPHONSUS 'Entschlichten der wichtigsten Schlichtefamilien auf Polyesterfilamentgarnen' siehe Tabellen 1-3 A EP,A,0 055 975 (CIBA GEIGY) 14. Juli 1982 1 siehe Beispiel 2 Farmiblatt. PCT/ISA/210 (Fortsettung van M~att 2) (Jul! 1992) Seite 2 von 2 I INTERNATIONALES RECH ERC I ENSERICHT Angzben zu Vcrdtfentlichunsun, dic zur selhen Ps cntfvsnlie gchbrcn Intert ,Wico Aktunzichen PCT/EP 94/00265 Im Recherchenbcricht Datum der Mitgfied(er) der I Datum der angefthrtes Patentdokumerit Verbffenrdichung Patentfaxnilic Verdffentlichting DE-A-2543815 14-04-77 AT-B- BE-A- CH-A, B FR-A, B GB-A- JP-A- NL-A- SE-A- US-A- 353215 846579 615797 2326531 1561798 52043885 7610697 7610871 4095947 12-11-79 24-03-77 29-02-80 29-04-77 05-03-80 06-04-77 05-04-77 02-04-77 20-06-78 EP-A-0055975 14-07-82* US-A- 4426203 17-01-84 Formblatt PC/ISA1210 (Ainhang PatetfamidhC)(Juli 1992)