JP3479076B2 - Fabric treatment - Google Patents

Abstract

The degree of fibrillation and/or the tendency to fibrillation of lyocell fabric can be reduced by treating the fabric with a low-formaldehyde or zero-formaldehyde crosslinking resin, heating the treated fabric to cure the resin, and washing and drying the fabric. The treatment can be applied to dyed fabric.

Description

TECHNICAL FIELD The present invention relates to a method of reducing the degree of fibrillation and the tendency of fibrillation of solvent-spun cellulosic fibers, known as lyocell fibres.

2. Description of Related Art It is known that cellulosic fibers are obtained by extruding a solution of cellulose in its appropriate solvent into a coagulation bath.
This process, consisting of extrusion and coagulation, is a solvent-spinning process.
The cellulosic fibers thus obtained are referred to as "solvent-spun" cellulosic fibers. An example of such a method is described in US Pat. No. 4,246,221, the content of which is incorporated herein by reference. Cellulose is
It is soluble in solvents such as tertiary amine-N-oxide. The solution is extruded through a suitable die into filaments which are coagulated, washed with water to remove the solvent and dried. Generally, at some manufacturing stage, the filaments are cut into short lengths into staple fibers.

It is also known that cellulose fibers can be produced by extruding a solution of a derivative of cellulose into a regeneration bath and a coagulation bath. An example of such a method is the viscose method. In the viscose method, the cellulose derivative is cellulose xanthate. Both such method types are examples of wet methods. The solvent spinning method has a number of advantages over known cellulosic fiber production methods such as the viscose method, such as reduced environmental emissions.

The term used here, "lyocell fib
re) ”means cellulose fibers obtained by an organic solvent spinning method. In the organic solvent spinning method, the solvent is essentially a mixture of an organic chemical agent and water. Solvent spinning is a derivative of cellulose. Consisting of dissolving and spinning the cellulose without the formation of The term "solvent-spun cellulose fiber" used here means "lyocel fiber (lyoc
ell fiber)))) is a synonym. As used herein, a lyocell fabric means a fabric woven or knitted from a plurality of yarns containing lyocell fibers alone or in a blend at least in part.

Fibers tend to fibrillate when subjected to mechanical stress, especially in the wet state. Fibrillation causes the fine fibrils to partly separate from the fibers when the fiber structure breaks in its longitudinal direction, giving the fibers or, for example, knitted fabrics containing them, a fluffy appearance. Dyed fabrics containing fibrillated fibers tend to have a frosted appearance, which is aesthetically undesirable. Such fibrillation is believed to occur due to mechanical rubbing of the fibers during processing in the wet or swollen state. Wetting processes such as refining, bleaching, dyeing and washing inevitably subject the fibers to mechanical abrasion. Higher temperature treatments and longer treatments tend to cause a greater degree of fibrillation. Lyocell fiber fabrics appear to be particularly sensitive to such friction. And it is often pointed out that it is easier to fibrillate than fabrics such as woven fabrics made from other types of cellulosic fibers. Cotton fibers are fibers which by nature have a particularly low tendency to fibrillate.

EP-A-538,977 was prepared from fibrillated lyocell fiber fabric by treatment with a solution of cellulase,
It describes that fibrils are removed. Cellulase is an enzyme that has a catalytic action on the hydrolysis of cellulose. However, such treatment is not so desirable, and the waste treatment of the used enzyme solution may cause environmental problems.

Treating a cellulosic fabric with a crosslinker to improve the wrinkle resistance of the cellulosic fabric is described, for example, in Wiley-I.
Kirk-Othmer's Encyclopaedia of Ch in nterscience
emical Technology, third edition, volume 22 (198
3) pp. 769-790, "Fiber (Finishing)", and
Rev. Prog. Coloration, Vol.17 (198 by H. Petersen
7), it has been known for many years as described in the papers on pages 7 to 22. Cross-linking agents are sometimes referred to differently as, for example, cross-linkable resins, chemical finishes or resin finishes. The cross-linking agent is a small molecule substance containing a plurality of functional groups capable of reacting with the hydroxyl groups of cellulose to form cross-links. In a conventional type finish, the cellulosic fabric is first treated with a cross-linking agent, such as by applying a pad bath, dried, and heated to cure the resin and cause the cross-linking reaction to occur ( Pad-dry-cure method). Wrinkle-proofing is known to impair the friction resistance, tensile strength and tear strength of cellulosic fabrics.

Early cross-linking processing systems were with urea-formaldehyde and melamine-formaldehyde resins. These processing systems had many problematic drawbacks. This treatment method temporarily hardens the cloth because there is a resin adhering to the outside. The processed fabrics tended to produce an unpleasant odor during storage, which was due to the amine catalyst used to cure the resin and the toxic chemical agent formaldehyde. Therefore, it has been considered necessary to wash the processed fabric in order to remove the externally attached resin and the resin-forming by-product that emits an unpleasant odor. Such washing and subsequent drying of the treated fabric adds an additional burden to the cost of processing.

Therefore, such processing systems have been largely replaced by systems containing so-called "low-formaldehyde resins" and "free-formaldehyde resins" as crosslinkers. One known example of such a treating agent is an N-methylol resin, ie a treating agent consisting of a small molecule compound containing two or more N-hydroxymethyl or N-alkoxymethyl, especially N-methoxymethyl groups. Is.

The N-methylol resin is generally used in combination with a catalyst selected to improve the crosslinking performance. In a typical processing method, a solution containing about 5-9% by weight N-methylol resin crosslinker and 0.4-3.5% by weight acid catalyst is padded onto the dry cellulosic fabric at 60-100% by weight pick-up and then the wet fabric. Is dried and then heated to cure and fix the crosslinker. Fabrics treated with low-formaldehyde resins or non-formaldehyde resins generally do not undergo a temporary curing phenomenon and do not give off an unpleasant odor. Cured textile fabrics and processed garments are rarely washed before being sold to consumers.

SUMMARY OF THE INVENTION A method of reducing the fibrillation tendency of a lyocell fabric according to the first aspect of the invention comprises the following steps: (a) treating the fabric with a low formaldehyde or aldehyde-free crosslinkable resin; (b) the fabric. Heating under conditions effective to allow the resin to react with the cellulose; (c) washing the fabric; and (d) drying the fabric.

In this and other aspects of the invention, the fabric is treated with the crosslinkable resin in the form of a flat fabric and heated to cause a reaction between the cellulose and the resin in the form of the fabric fabric.

In one particular embodiment of this and other aspects of the invention, the fabric being washed in the form of a flat fabric and heated, which is the preferred form, is then used for the production of garments and other textile articles. Cut into pieces.

In yet another specific embodiment of this and other aspects of the invention, the fabric is first dressed into clothing or other fiber article, then washed and dried to complete the invention. Let

A method of reducing the degree of fibrillation of a lyocell fabric according to the second aspect of the present invention comprises the steps of: (a) treating the fabric with a low formaldehyde or aldehyde-free crosslinkable resin; Heating under conditions effective to cause a reaction between the resin and cellulose; (c) washing the fabric; and (d) drying the fabric.

A method of reducing the degree of fibrillation of a lyocell fabric according to the third aspect of the present invention comprises the steps of: (a) refining and dyeing the fabric, thereby inducing fibrillation in the fabric: (b) Treating the fabric with a low formaldehyde or aldehyde-free crosslinkable resin; (c) heating the fabric under conditions effective to cause a reaction between the resin and cellulose; (d) the fabric. And (e) drying the fabric.

In this third aspect of the invention, bleaching may optionally be carried out between the refining and dyeing process of step (a) and drying between steps (a) and (b) is also optional. is there. After step (c), the fabric may exhibit a high degree of fibrillation tendency to which the fibrous articles made therefrom are commercially unacceptable. Step (e)
After that, the fabric, in the form of a flat fabric or a fibrous article, exhibits a very low commercially desirable degree of fibrillation.

Preferred crosslinkable resins are N-methylol resins. Examples of suitable N-methylol resins are the previously mentioned Kirk-
It is described in Othmer's paper and Petersen's paper. Such resins include, for example, 1,3-dimethylol ethylene urea (DEMU), 1,3-dimethylol propylene urea (DMPU) and 4,5-dihydroxy-1,3-dimethylol ethylene urea (DHDMEU). Contains. Urons,
Some examples include compounds based on triazinones and carbamates. Other examples of preferred crosslinking agents consist of compounds based on the class of 1,3-dialkyl-4,5-dihydroxy (alkoxy) ethylene ureas and their derivatives. A further example of a suitable crosslinking agent is melamine. A further example of a suitable crosslinker is butane tetracarboxylic acid (BTCA). One or more types of cross-linking agents may be used.

A cross-linking agent for wrinkle-proofing of cellulose cloth is generally used in combination with a catalyst. The catalyst has a function of promoting a crosslinking reaction and resin curing and fixing. The method of the present invention preferably utilizes such catalysts when it is recommended to use them in combination with the crosslinker selected for use. For example, N-methylol resins are preferably used in combination with organic acid catalysts such as acetic acid or metal acid catalysts such as zinc nitrate or magnesium chloride. Latent acids such as ammonium salts, amine salts or metal salts can also be used. Mixed catalyst systems can also be used.

The crosslinker and any catalyst are preferably applied to the fabric from a solution in water. This solution can be applied to the fabric in a known manner, for example by padding the fabric with the solution or by dipping the fabric in a treatment bath of the solution. The fabric can be either woven or knitted. Solution is at least about 2 by weight
%, Preferably about 6% crosslinker. When a catalyst is used, the solution may contain at least about 1% by weight catalyst, preferably about 1% to about 2%.

After treatment with the crosslinkable resin according to the present invention, the fabric is heated to fix and cure the crosslinker. The fabric may be dried. The heating process may partly precede or follow the drying step. The time and temperature required for the heating step depends on the nature of the cross-linking agent and the catalyst employed as appropriate. After being heated and optionally dried, the fabric is at least about 0.
5%, preferably at least 1.0%, more preferably at least about 2%. Generally, the fabric does not exceed about 4% crosslinker weight calculated on cellulose weight. In general,
It was found that about 70 to 90% of the crosslinker in the wet fabric was fixed to the cellulose.

The concentration of resin in the bath is selected to give the required amount of fixed resin deposit on the fabric, depending on the activity of the resin and the efficiency of curing.

After heating and fixing, the fabric is washed and dried according to the conventional processing processes for cellulosic fabrics.

Fabrics treated according to the present invention exhibit a greatly reduced degree of fibrillation. This is surprising because the cross-linking treatment was generally thought to reduce the friction resistance of cellulosic fabrics. It is known that the method of the present invention requires an additional wet processing step, and that the wet processing step as described above causes fibrillation of the lyocell fabric. The more treated fabrics of the present invention have excellent fibrillation resistance as compared to untreated fabrics,
Suitable for the production of textile products such as clothing. Such textiles have little or no slow loss of reduced fibrillation tendency upon washing.

The method of the present invention is also applicable to dyed fabrics, including fabrics dyed by methods such as rope dyeing which are known to cause mechanical abrasion. This is an advantage of the present invention. This is because the rope-like processing of the fabric enhances the bulkiness and relaxation of the fabric, which leads to an excellent texture. The method of the invention is already fibrillated,
For example, it can be applied to fabrics that are severely fibrillated. When highly fibrillated fabrics were treated by applying the method of the present invention, it was surprisingly found that the treated fabrics exhibit significantly lower levels of fibrillation. In most cases, fabrics that exhibit a high degree of fibrillation are
Considered a mediocre product that is judged not to require costly additional processing. It is a particular advantage of the present invention that the fabrics that are mediocre products can be converted to first grade fabrics and textiles.

The degree of fibrillation of the material is evaluated using the method described below as Test Method 1.

Test Method 1 (Evaluation of fibrillation) There is no universally accepted standard fibrillation evaluation method. Therefore, the fibrillation index (FI) was evaluated using the following method. Fiber samples were arranged in series with increasing degrees of fibrillation. The reference length of the fiber of each sample was measured, and the number of fibrils (thin fibrils extending from the body of the fiber) was counted along the reference length. The length of each fibril was measured, and a number, which was the product of the number of fibrils times the average length of each fibril, was determined for each fiber. The fiber with the highest value for this product is considered to be the most fibrillated fiber and the fibrillation index (Fi
brilation Index) 10. A fiber fibrillation index of 0 with no fibrill was assigned and the remaining fibers were evenly assigned in the range 0 to 10 based on the numbers measured by microscopy.

A standard evaluation scale was prepared using the measured fibers. To determine the fibrillation index of any other fiber sample, 5
Or 10 fibers were visually compared under microscope to this standard scale. Next, the numerical values visually obtained for each fiber were averaged to obtain a fibrillation index corresponding to the test sample. It can be seen that the visual measurement and averaging method is often faster than the actual measurement method. Skilled textile engineers have been shown to agree on their own assessment of the fibers.

The fibrillation index of a fabric can be evaluated for fibers drawn from the surface of the fabric. Woven and knitted fabrics having a fibrillation index of about 2.0 to 2.5 or higher have a poor appearance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is illustrated by the following examples. Used in each case, it has never been dried (never-drie
d) The fiber is N-methylmorpholine-N-oxide (NMM
It was prepared by discharging the cellulose solution of O) into an aqueous bath and washing the formed fibers with water until the NMMO disappeared.

Example A lyocell 100% spun yarn fabric having an FI of 0 was desizing, refined and dyed with a jet dyeing machine. Desizing is 1.5g / l
Of commercially available amylase, pH 6.5-7.5, 70 ° C
Then, it took 45 minutes. Refining was carried out at 95 ° C. for 60 minutes using an aqueous solution containing 2 g / l of sodium carbonate and 2 g / l of an anion detergent. 4% owf dye, Procion Navy HE-
It was carried out at 85 ° C. for 120 minutes using an aqueous solution containing R 150 (Procion is a trademark of Zeneca plc), 80 g / l sodium sulfate, and 20 g / l sodium carbonate. This cloth is first 70 ℃
2 g / l Sandopur SR, rinsing with water, then ambient temperature
(Sandpur is a trademark of Sandoz AG) at 95 ℃, 2
It was soaped for 0 minutes, drained and dried. This method is a typical rope-like treatment process for cellulosic fabrics. The treated fabric was severely fibrillated with a FI of 4.5.

Dyed fabric sample with low formaldehyde resin DHDMEU
It was padded with an aqueous solution containing various amounts of it (supplied by Hoechst AG under the trademark Arkofix NG conc). This solution contained the acid releasing catalyst at 25% by weight of Arkofix NG conc according to the resin supplier's recommendations. The fabric sample was then dried at 110 ° C and then the resin was flash cured at 180 ° C. The sample fabric was then remounted on the jet dyer and scoured twice as before. The sample fabric was then dehydrated and a silicone softener (Rudolf Chem
Aqueous dispersion containing 50 g / l of the trademark Rucofin A0736 available from ical Ltd.) was padded onto the as-wet fabric and dried at 110 ° C. The results are shown in Table 1.

The numerical value of the amount of resin fixed on the fabric is Arkofix NG c
It is a value estimated based on 70% active solid content of onc, 80% indicator liquid and 80% cure efficiency.

During these additional wet treatments, the FI of the untreated fabrics increased from 4.5 as expected, while the resin-treated fabrics had an FI of 4.5 to 4.5 at commercially acceptable levels.
It can be seen that it has actually decreased to 1.9 or less.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI // D06M 101: 06 D06M 101: 06 (56) References JP-A-5-117970 (JP, A) JP-A-6-146168 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) D06M

Claims (13)

(57) [Claims] 1. A method for producing a solvent-spun cellulosic fiber fabric exhibiting a low degree of fibrillation and having a low fibrillation tendency, the method comprising sequentially applying the following steps in the order listed. Method: (a) refining and dyeing the fabric, thereby causing fibrils in the fabric, (b) treating the fabric with a low-formaldehyde or formaldehyde-free crosslinked resin, (c) treating the fabric with a resin And heating under conditions sufficient to cause a reaction between the cellulose and the cellulose, (d) washing the fabric, and (e) drying the fabric. 2. The method according to claim 1, wherein the dyeing step is performed in a rope shape. 3. A method according to claim 1 or 2, characterized in that the method comprises a bleaching step following the refining step and prior to the dyeing step. 4. The method of claim 1, wherein the method comprises the step of dyeing the fabric, followed by drying the fabric prior to treating the crosslinkable resin fabric.
3. The method according to any one of 3 to 3. 5. A method for reducing the tendency of a solvent-spun cellulose fiber fabric to fibrillate, the method comprising sequentially applying the following steps in the order listed: (a) a fabric containing low formaldehyde. Or treatment with a formaldehyde-free crosslinkable resin, (b) heating the fabric under conditions sufficient to cause a reaction between the resin and the cellulose, (c) washing the fabric, and (d) Drying the fabric. 6. A method for reducing the degree of fibrillation of a solvent-spun cellulose fiber fabric, the method comprising sequentially applying the following steps in the order listed: (a) a fabric Treating with a low formaldehyde or formaldehyde-free crosslinkable resin, (b) heating the fabric under conditions sufficient to cause a reaction between the resin and the cellulose, (c) washing the fabric, and (d) ) Drying the fabric. 7. A method according to any one of the preceding claims, characterized in that the washing and drying steps followed by the heating step are carried out on a flat shaped fabric. 8. A method according to any one of claims 1 to 6, characterized in that the fabric is made into a garment or other textile product after the heating step, prior to the washing step. 9. The method according to claim 1, wherein the crosslinkable resin comprises at least an N-methylol resin. 10. The method according to claim 9, wherein the N-methylol resin is used in combination with an acid catalyst. 11. The crosslinkable resin is uron, triazinone, carbamate, 1,3-dialkyl-4,5-dihydroxy (alkoxy) -ethylene urea and derivatives thereof,
The method according to any one of claims 1 to 8, which comprises at least one resin selected from the group consisting of melamine and butanetetracarboxylic acid. 12. A method according to any of the preceding claims, characterized in that the treating step is carried out by applying to the fabric a cross-linking agent in an aqueous solution containing 3 to 6% by weight. How to do. 13. A fabric according to any one of the preceding claims, characterized in that, after the heating step, the fabric contains at least 2% by weight, based on the weight of cellulose, of a fixed crosslinker. Method.