KR101245390B1 - Cross-linking and dyeing cellulose fibres - Google Patents

Abstract

A process for producing an evenly-dyed fabric comprising both cotton fibres and man-made cellulose fibres, in which a fabric is manufactured from both said fibres and is dyed, is characterised by impregnating the man-made cellulose fibres, prior to manufacture of the fabric, with a water-soluble, flexible linear polymer and a cross-linking agent reactive with cellulose, and, at a stage of the process prior to dyeing of the fabric, effecting a cross-linking reaction between the man-made cellulose fibres and the cross-linking agent, thereby producing a reduction in the dye affinity of the man-made cellulose fibres to a level more proximate to the dye affinity of the cotton fibres.

Description

Cross-linking and dyeing cellulose fiber manufacturing method {CROSS-LINKING AND DYEING CELLULOSE FIBRES}

The present invention relates to a method of making crosslinked and dyed cellulose fibers comprising the step of crosslinking artificial cellulose fibers and dyeing a fabric made from such fibers.

Artificial cellulose fibers are made by spinning a spinning solution from a source of natural cellulose, such as wood pulp, and spinning the spinning solution. Lyocell fibers are artificial fibers made by extruding a cellulose solution through a spinning jet into a coagulation bath by a process known as solvent spinning. Such solvent spinning methods are described in US Pat. No. 4,246,221, in which an aqueous tertiary amine N-oxide, in particular N-methylmorpholine N-oxide, is used as the solvent. Lyocell fibers are distinguished from other artificial cellulose fibers produced by the formation of soluble chemical derivatives with cellulose and extrusion of the derivative solution into the bath to regenerate the extrudate into cellulose fibers. Viscose fibers comprising a high strength modal type are prepared by forming soluble derivatives in the manner described above.

Crosslinker treatments on cellulose fabrics are already known to impart wrinkle resistance, durable compression or wash-wear characteristics to this type of fabric. A general description of these treatments is published by Willy-Intercience, published by Kirk-Otmouth Incyclopedia of Chemical Technology, 3rd edition, Volume 22 (1983), pages 769-790, entitled “Textiles”. And in "Rev. Prog. Coloration", Vol. 17 (1987), pages 7-22. Revealed by Peterson. Crosslinkers may also be called by other names, for example, crosslinking resins, chemical finishes and resin finishes. Crosslinkers are small molecule materials that contain a number of functional groups that react with hydroxyl groups in cellulose to form crosslinks. One type of crosslinker comprises an N-methylol resin, which is a small molecule of material comprising two or more N-hydroxymethyl or N-alkoxymethyl, in particular N-methoxymethyl groups. N-methylol resins are generally used with selected acid catalysts to improve crosslinking performance. In a typical process, a solution comprising about 5-9 wt% N-methylol crosslinked resin and 0.4-3.5 wt% acid catalyst is immersed in dry cellulose to absorb about 60-100 wt% and then wet fabric The crosslinker is cured by heating to dry and cure.

Wrinkle-resistant finishes are known to destroy cellulose fibers, reducing the fabric's wear resistance, tensile strength and tear strength. It is therefore important to strike a balance between wrinkle resistance and other physical properties.

It is also already known that crosslinking treatments as described above reduce the dye affinity of cellulose fabrics. The reduction in dye affinity by 50 to 60% compared to similar crosslinker untreated cellulose fabrics has been pointed out as a serious drawback of crosslinking treatment. Attempts have been made to use linear polymers bound to cellulose by crosslinkers to improve this reduction of dye affinity. This attempt was partly successful.

For example, U.S. Patent No. 4,780,102 describes a process for treating crosslinked cotton fabrics for imparting wash-wear characteristics by dipping the fabric in N-methylol crosslinkers, acid catalysts to promote crosslinking reactions and polyethylene glycol. have. In this method the fabric was dried and then heated to allow crosslinking reaction to occur before dyeing. The inclusion of polyethylene glycol was such that the crosslinked fabrics were post-dyed with cellulose dyeing dyes such that the desired wash-wear characteristics imparted by the crosslinking treatment were exhibited. The level of dyeing achieved by this method is still low compared to cotton fabric without crosslinking treatment. This treatment has the advantage of treating the crosslinker as a printing composition such that when post-dyed, different dyeing effects are seen in the printed and unprinted portions.

Another method of maintaining a balance between the advantages of crosslinkers and maintenance of dye affinity is described in US Pat. No. 5,580,356. In this method crosslinking proceeds to reduce the fibrillation tendency of lyocell fibers. Flexible linear polymers, such as polyethylene glycol, are used with crosslinkers to impart dye affinity to the crosslinked lyocell fibers in a post-dyeing process.

Another method for dyeing cellulose, including fabrics, is described in US Pat. No. 4,629,470 and US Pat. No. 5,298,584.

The present invention provides a method of using the above-described crosslinking process but solves the problems exhibited by the reduced dye adsorption of cotton fabrics as opposed to artificial fibers such as lyocells and viscose fibers.

The present invention relates to a method for producing a uniformly dyed fabric comprising a cotton fiber and an artificial fiber and made from the two fibers described above and dyed, wherein the method is made of a water-soluble flexible The dye affinity of the artificial cellulose fibers causes the crosslinking between the artificial cellulose fibers and the crosslinking agent to be immersed in a crosslinking agent reactive with the linear polymer and cellulose and before the fabric is dyed. Provided are methods of making uniformly dyed fabrics characterized in that they are reduced to a level similar to affinity.

According to the present invention, uniform dyeing is obtained on the fabric so as to be the same color dye as opposed to the formation of the whims, scratches and spots that are usually obtained when the blended fabric is dyed.

The dye affinity of the fibers is relative and is measured by a test method in which a metered fabric sample is dyed using standardized salt baths and processes. The color intensity obtained is measured with a spectrometer and compared with the values obtained when the control fabrics of the same composition and weight are dyed and measured in the same manner. The value given for the control is assumed to be 100% and the value shown in the fabric compared to the control is shown as the ratio of the measured value to 100%. The dye affinity test used to measure the dye affinity of the fibers according to the process of the present invention is described below.

The uniformity of the dyeing required to obtain the same color dye of the color is generally determined visually. The standard of uniformity required may vary depending on the end use of the dyed fabric and the dye color used. The latter case, for example yellow, may be more whimsical than dark blue dyes. With this in mind, I believe that if the dye affinity of artificial cellulose fibers is reduced to around 15%, especially within 15% on both sides, especially the top side, assuming 100% cotton fibers, It has been found that staining can be obtained using the method of the present invention.

Depending on the raw material and the processing method, when the dye affinity obtained from cotton fiber is 100%, the standard Viscose fiber has a dye affinity of 130% and the standard lyocell fiber has a dye affinity of 140%. Despite such differences in dye affinity between artificial cellulose fibers and cotton fibers, the method of the present invention yields uniformly dyed blend fabrics.

The method of the present invention exhibits the desired effect when the artificial fiber is a lyocell fiber, but also works on other artificial fibers such as viscose fibers.

Dipping the artificial cellulose fibers in the crosslinker may be immersed in the form of fibers or in the form of yarns. Preference is given to treating the fibers in a solution state with the flexible linear polymer and crosslinker in the undried state, i.e., before the fibers are wet spun and primary dry before the fibers are spun into the yarn.

The crosslinker may be a known one used for the wrinkling prevention of cellulose, but a formaldehyde free or low formaldehyde based crosslinker is preferable. Particularly preferred is the use of crosslinkers with crosslinking catalysts. In particular, crosslinkers suitable for use in the present invention are formaldehyde-free crosslinkers that do not include formaldehyde.

Low-formaldehyde crosslinkers include N-methylol resins. Examples of suitable low-formaldehyde N-methylol resins are those disclosed by Kirk-Hautmer and Peterson described above. Examples of such resins include 1,3-dimethylrollethylene urea (DMeEU), 1,3-dimethylrollpropylene urea (DMePU) and 4,5-dihydroxy-1,3-dimethylrollethylene urea (DHDMeEU). . Other examples include compounds based on Euron, triazinone and carbamate. Another suitable crosslinker is melamine.

Preferred examples of formaldehyde-free crosslinkers are 1,3-dialkyl-4,5-dihydroxy (alkoxy) ethylene urea, for example 1,3-dimethyl-4,5-dihydroxyethylene urea (DMDHEU) There is a theme. Another example of a preferred formaldehyde crosslinker is butanetetracarboxylic acid (BTCA). Crosslinkers used in the anti-wrinkling finish of cellulose fibers are generally used in combination with catalysts for crosslinking reactions, for example acid catalysts. In the process of the invention it is preferred to use the aforementioned catalysts which are recommended for use with the selected crosslinking agent. N-methylol resins and 1,3-dialkyl-4,5-dihydroxy (alkoxy) ethyleneurea are acid catalysts, for example organic acids such as acetic acid or ammonium salts, amine salts or metal salts such as zinc nitrate and magnesium chloride. Preference is given to using together with acid catalysts containing latent acids such as these. The mixed catalyst which mixed 2 or more types selected from the above-mentioned acid catalyst can also be used.

The water soluble flexible linear polymer is preferably a fully aliphatic polymer, in particular an unbranched aliphatic polymer. Such polymers have terminal functional groups, such as hydroxyl groups or amino groups, and these groups participate in reactions with crosslinkers. The effect of the flexible linear polymer is to mitigate the degradation of the dye affinity of the artificial cellulose fibers by crosslinking so that the dye affinity is close to the dye affinity for cotton fibers. This effect is obtained during the crosslinking reaction by maintaining the degree of opening to allow for sufficient dye adsorption to allow the dyeing of the cellulose fiber structure to be obtained and to prevent the fiber structure from collapsing. After dyeing, the fibers should be washed so that the functional groups are not included in the crosslinking reaction so that the soluble polymer no longer functions.

Preferred flexible linear polymers include polymerized glycols such as polypropylene glycol (PPG), with the most preferred glycol being polyethylene glycol (PEG). Amine-type oils of such glycols may also be used. Such flexible linear polymers can generally be mixtures of molecules having a specific range of chain lengths and molecular weights. For example, the chain length can range from 5 to 150 atoms. Preferred examples of flexible polymers are PEGs having an average molecular weight of 200 to 2000.

Crosslinkers, linear polymers and catalysts are preferably treated to cellulose fibers in the form of solutions, in particular aqueous solutions. Polymerized glycols such as PEG and PPG are generally water soluble. The solution is treated to the fibers by known methods, for example by dipping the tow, in particular un-dried tow, into the solution or by passing the tow into the treatment bath. The fibers may be treated in the form of staple fibers. The undried fibers may have a water content of about 45 to 65% by weight, in particular about 50% by weight, after treatment with the solution. The treatment solution may comprise 0.5 to 15 wt%, preferably 1.5 to 5 wt% crosslinking agent (based on 100% activity criteria). The treatment solution may also comprise 0.1 to 5% by weight of the flexible linear polymer. If a catalyst is used, the amount of catalyst in the solution is 0.1 to 5% by weight, preferably 0.25 to 2.5% by weight. The solution may also include other materials such as soft finishes used to treat the fibers.

Treated artificial cellulose fibers comprise from 0.2 to 5% by weight, preferably from 1 to 4% by weight of crosslinking agent and from 0.1 to 3% by weight of the flexible linear polymer, based on the cellulose weight.

Fabrics made of immersed artificial cellulose fibers and cotton fibers may be knitted or plain or nonwoven. In the case of knitted or plain fabrics, the fibers are first spun into yarn. A preferred method is to blend the immersed artificial cellulose fibers and cotton fibers to make a yarn. Another alternative is to make separate yarns from immersed artificial cellulose fibers and cotton fibers and to mix the yarns to make a fabric when the fabric is made. Blend ratios may vary depending on the end use of the fabric, but most commonly blend ratios are blends of artificial cellulose fibers and cotton fibers in a ratio of 70:30 to 30:70, with the most preferred blend ratios of 50 It is mixed at a ratio of: 50.

The crosslinking or curing step takes place before drying. If any other wet treatment is performed prior to drying, crosslinking should be effected before other wet treatments as this may result in the loss of crosslinking chemicals from the yarn treated during the wet treatment step. It is desirable to allow crosslinking to occur in fabrics or yarns. If the planned fabric is a knit or nonwoven, it is desirable to allow crosslinking to occur in the fabric. If the planned fabric is a plain weave, it is desirable to allow crosslinking to occur in the yarn state since there is a risk of loss of the crosslinker from the yarn in the warp pasting step, which is usually carried out before weaving if it is not already crosslinked. Crosslinking in the fibrous state is also possible, but crosslinked fibers are not desirable because they become hair-shaped, making it difficult to pull out yarns or fabrics.

A preferred process is to immerse artificial cellulose fibers with a crosslinker and a flexible linear polymer, blend the immersed fibers with cotton fibers, then form yarns with the blended fibers and weave the fabric with the formed yarns and then crosslink the yarns or fabrics. To cause the union to happen. In the case of plain weave, it is desirable to allow crosslinking to occur in the yarn.

Crosslinking is effected by heating for a suitable temperature and time depending on the crosslinking agent and catalyst used to allow crosslinking to occur. If crosslinking occurs in the fabric, it is desirable to pass the fabric through the stent into the hot air. Suitable crosslinking conditions require a temperature in the range of 140 ° C. to 200 ° C. and a time of 30 seconds to 5 minutes. The treatment is preferably performed at a high temperature since the treatment is for a short time rather than a low temperature.

Initial drying, for example drying of the tow after crosslinking agent treatment, should be carried out at low temperatures so that no crosslinking occurs prematurely. For example, it is preferable to keep the temperature of the fiber at a temperature of 110 ° C. or lower during drying, independent of the air temperature. In addition, the fibers should be dried so that the water content does not fall below 7% by weight of the fibers.

Dyeing of the fabric is carried out using dyes and methods commonly used to dye cellulose fabrics. Suitable dyes include direct dyes, bat dyes, sulfur dyes and reactive dyes. Dyeing machines are conventional dyeing machines used, for example, hydraulically-driven jet dyeing machines such as Thais Ecosoft, Gaston County Futura and Hisaka Sucura Shiyuti-SL and Thaies Airstream, Thais. Air jet dyeing machines such as a dyeing machine known as Luput Roto, Hisaka AJ-1, Crants Aero Die and Den A. F.

One example of the invention includes an undyed fiber product comprising cotton fibers and artificial cellulose fibers, wherein the artificial cellulose fibers are immersed and immersed in a water soluble plastic linear polymer and a crosslinking agent reactive with cellulose. The artificial cellulose fibers thus obtained were not crosslinked but had a reduced latent dye affinity similar to the dye affinity of cotton fibers by the crosslinking reaction between the artificial cellulose fibers and the crosslinker prior to dyeing the fibrous product.

A first example of such an undyed fiber product may be an undyed mixture of cotton fibers and dipped artificial cellulose fibers, a yarn made from such a fiber mixture, or a fabric made from such yarns. The undyed fiber product may also be a fabric made of yarn comprising artificial cellulose fibers that are immersed with cotton fibers but not crosslinked.

Another example of the invention may be a yarn or fabric. Such yarns or fabrics may also include cotton fiber yarns and yarns of artificial cellulose fibers.

The dye affinity of the preferred crosslinked artificial cellulose is on the order of 15% of the cotton fiber dye affinity in the specified experiment, which assumes 100% cotton fiber as the control fiber.

The invention also includes the crosslinked fabric of the second example described above in the form of a fabric dyed uniformly in the same color dye state.

The dye affinity test chosen in the Examples to determine the benefits according to the invention uses an aqueous salt bath combining 0.05% Solophenyl Green 27 (direct dye) and 10 g / l sodium chloride. 5 g of the sample fabric is made to have a weight ratio of salt to fiber of 20: 1, dyed at a salt bath temperature of 95 ° C. for 45 minutes, the salt bath is cooled, and then the sample fabric is rinsed and dried.

The color intensity of each dyed sample fabric was measured using a Minolta Siem-3300D spectrometer, and all readings were evaluated relative to the dyed control sample fabric set at 100%. In the case of the present invention, since it is carried out in order to obtain a uniform dyeing of the blend fabric, cotton fabric was used as a control fabric.

For fairness between the test fabrics, the test fabrics used the same number of yarns (20 tex), the same fabric (plain weave) and the same sample weight (5 g). Prior to dyeing, all the fabrics were refined at 70 ° C. for 30 minutes in a scouring bath containing 2 g / l of soda and 2 g / l of Zetex HFCL.

Hereinafter, the present invention will be described in detail by way of examples.

Examples 1 and 2

The lyocell fiber is a conventional method of spinning a cellulose solution dissolved in an aqueous solution of N-methylmorpholine N-oxide into an aqueous coagulation bath through a spinning jet to form a filament tow-shaped fiber in a conventional manner. Cell fibers are formed and the spun tow is washed.

The washed filament tow was subjected to a 55 ° C. aqueous padding bath containing DMDHEU 30 g / l formaldehyde free and PEG (average molecular weight 400) and crosslinking catalyst 4 g / l magnesium chloride in an undried state. Pass through to soak. The soaked tow is passed through an oven maintained at 100 ° C. for 2 minutes and dried to a water content of 7% based on fiber weight.

In Example 1, the PEG concentration in the padding bath was 5g / l, and in Example 2, the PEG concentration was 10g / l. The PEG concentration for the fiber was 0.5 wt% owf in Example 1 and 1.0 wt% owf in Example 2. The samples were tested in a special way to examine the dye affinity of the fibers according to Examples 1 and 2. For the test, the tow was cut into 38 mm of staple tow, dried and then spun into a tow of 20 Tex yarns. A plain weave knit fabric was made from the yarn thus formed and the fabric was heated at 140 ° C. for 10 minutes to crosslink the crosslinker and resin in the fabric. Although crosslinking actually occurs within a shorter time, additional time was used to ensure complete curing. 5 g samples of this crosslinked fabric were used for specific dye affinity tests and compared to control samples made only of cotton fibers and standard lyocell fibers.

[table]

sample

Dye affinity
if

100
Standard lyocell

141
Standard viscose

131
Lyocell of Example 1

102
Lyocell of Example 2

114

The soaked and dried tows prepared according to Examples 1 and 2 were tested for uniformity of dyeing on the fibers when blended with cotton fibers. Again, the tow is cut into 38 mm long staple fibers and blended with combed cotton fibers in a 50:50 ratio. The fiber mixture is made of yarn of 30s Ne number and woven into a fabric of double jersey interlock structure with a basis weight of 200 gsm. Crosslinking of the resin in each fabric is caused by heating the fabric for 1 minute in a stenter oven at 170 ° C.

As a control a fabric of the same number and same structure was made from a 50:50 mixture of combed cotton and lyocell staple fibers, but the control fabric was not cross-linked with PEG.

The individual fabrics are held at 170 ° C. for 1 minute before being cut into cylinders and placed into a jet-dye. In this machine the fabric is refined for 30 minutes at 80 ° C. in a refining bath containing 2 g / l of A-Lube P60 (lubricant), 2 g / l of SandoClean PCT (detergent) and 2 g / l of soda. Refined fabrics are rinsed with hot water, rinsed with cold water and then dyed by hot transfer dyeing with hot reactive dyes. Aqueous salt baths contain the following components (usage is expressed in weight percent):

0.1% Frosion Dark Blue HI-EXL

0.2% Procion Crimson H-EXL

4.0% Frosion Amber H-EX

4 g / l A-Lube Pi 60

3 g / l Rudigol (anti-reducing agent)

2 g / l Depsodie Eldi-BuiAldi (Regulator)

60 g / l Glauber salt

20g / l soda ash

The salt bath is fixed at a temperature of 50 ° C. using a dyeing aid. The dye is then injected into the salt bath while raising the temperature of the salt bath to 95 ° C. at a rate of 2 ° C. per minute. The salt bath is kept at the same temperature for 30 minutes and then the temperature of the salt bath is cooled to 80 ° C. The soda ash is then divided into two portions over 15 minutes, firstly injecting three-quarters 1 into the salt bath and secondly, three-quarters 2, and then running the dyeing machine for 60 minutes. The salt bath is then cooled to 50 ° C. and the salt bath is then discharged from the dyeing machine. The dyed fabric is rinsed in the same dyeing machine and boiled in the dyeing machine.

While the fabric is in the dyeing machine, an aqueous flexible-finish bath comprising the following components is used for 20 minutes at 40 ° C. for a flexible treatment. The composition of the flexible bath is as follows. (Content is expressed by weight%)

1 ml / l acetic acid (40%)

0.5% Hansapin 2707 (silicone micro)

1% Edinine Sea Ace (polyethylene)

The fabric is taken out of the dyeing machine to remove moisture and allow it to dry naturally in the air.

The fabrics prepared in Examples 1 and 2 were both dyed with brown copper color to show no whimsical appearance and no slight tether. On the other hand, the control fabric was dyed with the same color, but uneven spots appeared due to the difference in dyeing of cotton and lyocell fibers.

Claims (19)

A method of making a uniformly dyed fabric comprising and dyed cotton fibers and artificial cellulose fibers, the method comprising the steps of reversing a reactive cellulose polymer with a water-soluble flexible linear polymer and cellulose prior to making the fabric into a woven fabric. Uniformly dyed, characterized in that the dye affinity of the cellulose fibers is approximated to the fiber affinity of the cotton fibers by immersing in the binder and causing a reaction between the crosslinking agent and the cellulose fibers in a step prior to dyeing the fabric. Method of making a fabric. The dye affinity of the crosslinked artificial cellulose fibers according to claim 1, wherein the dye affinity of the cotton fibers as measured by the dye affinity test of 100% cotton fibers in a test using cotton fibers as a control. Reduced by crosslinking to% level. The method of claim 1 or 2, wherein the artificial cellulose fibers are lyocell fibers. The method of claim 1 or 2, wherein the water-soluble flexible linear polymer and crosslinker penetrate the fiber when the artificial cellulose fiber is in the dry tow state. The method of claim 1 or 2, wherein the artificial cellulose fibers are immersed in a water-soluble flexible linear polymer and a crosslinking agent, and then the artificial cellulose fibers are mixed with cotton fibers to make a yarn from the mixed fibers, and the fabric is made from the yarns. Making a crosslinking reaction in the yarn or fabric. 6. The process of claim 5 wherein the fabric made from the yarn is a woven fabric and the crosslinking reaction occurs in the yarn. The process according to claim 1 or 2, wherein the crosslinker is formaldehyde free or low formaldehyde crosslinker and used with a crosslinking catalyst. The method according to claim 1 or 2, wherein the flexible linear polymer has terminal functional groups. The method of claim 8, wherein the flexible linear polymer is polymerized glycol. The method of claim 9 wherein the flexible linear polymer is polyethylene glycol (PEG). The method of claim 10 wherein the polyethylene glycol has an average molecular weight in the range of 200 to 2000. The method of claim 1 or 2, wherein the amount of linear polymer treated to the artificial cellulose fibers ranges from 0.1 to 3% by weight of the fibers. The method of claim 1 or 2, wherein the amount of crosslinker treated on the artificial cellulose fibers ranges from 0.2 to 5% by weight of the fibers. In non-dyed fiber fabrics comprising both cotton and artificial cellulose fibers, only artificial cellulose is immersed with a water-soluble flexible linear polymer and a crosslinking agent reactive with cellulose, and dipped artificial cellulose. Undyed, characterized in that the dye affinity of the cellulose fibers has a potential close to that of the cotton fibers, as the fibers are not dyed but a reaction occurs between the crosslinking agent and the cellulose fibers at the stage prior to dyeing the fabric. Textile products. 15. The undyed fiber product of Claim 14, wherein the fiber product is an undyed mixture of cotton and artificial cellulose fibers, a yarn made from the mixture, or a fabric made from such yarn. In non-dyed fiber fabrics comprising both cotton and artificial cellulose fibers, only artificial cellulose is immersed in a water-soluble flexible linear polymer and a crosslinking agent reactive with cellulose, and the crosslinking agent is a crosslinking reaction. Undyed fiber product, characterized in that by reacting with cellulose to reduce the dye affinity of the artificial cellulose fibers to a level close to the dye affinity of cotton fibers. 17. The method according to claim 16, wherein the dye affinity of the crosslinked artificial cellulose fiber is within 15% of the chlorine affinity of the cotton fiber when the dye affinity of the cotton fiber is 100% as measured in a test using cotton fiber as a control. Undyed textile product characterized by the high level. 18. The undyed fiber product of claim 16 or 17, wherein the fiber product is an undyed yarn or fabric. A textile product characterized in that the textile product according to claim 16 or 17 is a fabric dyed uniformly to have the same color.