KR101901665B1 - Cellulosic fibre with hydrophobic properties and high softness and process for production thereof - Google Patents

Abstract

The present invention relates to hydrophobic cellulosic fibers that are biodegradable and very flexible and water repellent. Nonwovens comprising the inventive cellulose fibers also exhibit greater flexibility. The fibers add bulk, better drape ability and hydrophobicity to biodegradable nonwoven fabrics when they are made solely of cellulose fibers.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellulose fiber having hydrophobic properties and high flexibility, and a method of producing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to cellulose fibers having greater flexibility and hydrophobic properties to represent bulk, and a method of making the same.

Cellulosic Man Made Fibers are known for their hydrophilic, water absorbing attributes. On the other hand, synthetic fibers such as polyester, polyethylene and polypropylene are inherently hydrophobic, meaning that they do not absorb water into the internal structure of the fibers. Some natural grown fibers, such as cotton, have realistic waxes that protect plants and make the raw fibers hydrophobic. Usually, these waxes are removed to achieve hygroscopic, flexible cotton fibers for textile and nonwoven processing.

Viscose type and modal type cellulosic fibers are made according to the viscose process. These fibers are provided by common name, viscose and modal by BISFA (The International Bureau for the Standardization of man made Fibers).

Recently, the "amine-oxide-process" or "lyocell process" has been established as an alternative to the viscose process, where cellulose is an amine-oxide, especially N-methylmorpholine- N-oxide (NMMO). Cellulose fibers made from these solutions are referred to as " solvent-spun "fibers and are supplied by Lysoell as generic name by BISFA (The International Bureau for the Standardization of man made Fibers).

Other artificial cellulosic fibers can be made using chemical processes (e. G., A cobaltammonium process) or using other direct solvents such as ionic liquids.

For hygiene applications, synthetic fibers such as polyester are widely used because they improve bulk, opacity, and flexibility in nonwoven and textile applications.

For ecological reasons, cellulose fibers and especially artificial cellulosic fibers continue to gain importance as they are made from renewable raw materials and are biodegradable. As a result, there is an increasing demand for cellulosic fibers that are flexible, hydrophobic, provide higher bulkiness and are biodegradable.

An object of the present invention is to provide a hydrophobic cellulose fiber which is biodegradable and water repellent. The fibers are very flexible and exhibit a higher bulk in nonwoven fabrics.

This object is achieved by a cellulose fiber comprising a hydrophobic surface preparation which is characterized in that the flexibility of the fiber according to the sledge test is at least 1.3 times higher than the flexibility of the cellulose artificial fibers of the untreated fiber of the same type It is characteristic.

Cellulose fibers can be natural grown fibers such as cotton or can be artificial cellulosic fibers such as viscose, modal or lyocell.

Cellulose artificial fibers may also be <

a) can be physically deformed, for example, in shape (trilobal, multilobal) or length (short cut with flock, continuous filament)

b) materials such as color pigments, flame retardants, ion exchange resins, carbon blacks may be incorporated,

c) can be chemically modified, as in the case of, for example, modal or crosslinked fibers.

In the context of the present invention, the term "untreated fiber" refers to a fiber whose surface is unmodified. In the case of newly spun fibers, i.e., never-dried fibers, the surface is initially un-modified. Commercially available fibers usually contain a soft finish which must be completely removed to have a non-modified surface prior to hydrophobic treatment.

The term "same type" means fibers of the same characteristics, titer and length.

As the hydrophobing agent, an alkyl or alkenyl ketene dimer (AKD) represented by the following formula (1) is used, wherein R1 and R2 are hydrocarbon groups having 8 to 40 carbon atoms, both of which are saturated Unsaturated, linear or branched:

Formulations with similar effects are substituted succinic anhydrides or glutaric anhydrides, and substituted cyclic dicarboxylic anhydrides such as the like.

Preferred alkylketene dimers are described, for example, in R. Adams, Org. Reactions Vol. III, p 129 John Wiley & NY 1946 or J.C. Saner; Journal of the American Chemical Society, Vol. 69, p. 2444 (1947). ≪ / RTI >

Alkylketene dimers (AKD) are well known in the paper industry for enhancing the water repellency of surfaces used, for example, in food packaging. The use of AKD is known for sizing papers as is known from GB 2 252 984 A and EP 0 228 576 B1. The co-use of AKD and ASA (alkylsuccinic acid) is described in WO99 / 37859. AKD is usually used at the wet end of a paper machine.

In a method for producing cellulosic fibers having hydrophobic properties, the method is characterized by the following steps:

a) providing a cellulosic fiber having a non-modified surface; and

b) treating the cellulose fibers with a hydrophobing agent.

The hydrophobing agent can be applied during artificial fiber production, which means that the fibers are already formed and washed, but before drying, i.e., non-dried fibers. In this case, the surface is non-modified.

When commercially available cellulosic fibers, including finishes, are used, this finish must be removed.

Hydrophobizing agents, such as AKD formulations, are commercially available (e. G., Hydrores? Compounds sold by Kemira). The most common is a formulation with approximately 5 to 25% active compound. In these examples, Formulation A is an acidic solution having approximately 10-12% active material and Formulation B is an acidic emulsion having approximately 20-22% active compound.

Cellulose fibers are preferably treated with AKD formulations in a concentration range of 0.0001% to 10%, preferably 0.001% to 5%, and most preferably 0.001% to 3%, based on the cellulose fibers.

The present invention is illustrated by the following examples.

General Procedure

The test was performed using Lengchin viscose, Lengthen tencel or cotton. Table 1 shows the main fiber types used. As a hydrophobing agent, AKD-formulation, for example Hydrores® from Kemira, was used. The commercially available formulations were diluted with water to have the concentrations described in the examples: AKD 1 means that the AKD solution used for this treatment was made from Formulation A and AKD 2 was used for this treatment Lt; RTI ID = 0.0 > AKD < / RTI >

Example  A Viscose (Sample 6)

7 g of finely dried viscose fibers, with the soft finish removed with alcohol, were immersed in 100 ml of an aqueous solution of Hydroresà (liquid ratio 1:15) containing 0.07 g of AKD (1% AKD for cellulose) at room temperature. After 30 minutes of agitation, the fibers were centrifuged until the fibers had a moisture content of 50% and dried at 70% in a dryer cabinet at a moisture content of 6%. The resulting fibers exhibit bulky, flexible, hydrophobic characteristics.

Example  B Viscose (Samples 4 and 5)

14 g viscose fibers from the viscose process were compressed to a moisture content of 50% (non-dried viscose) before post-treatment and 100 ml of a 100 ml Hydrores © containing 0.035 g AKD (0.5% AKD for cellulose) Was placed in a basin containing an aqueous solution (approximate liquid ratio 1:15). After 30 minutes of agitation, the fibers were centrifuged to a moisture content of 50% and dried in a drying cabinet at 70 DEG C to a moisture content of 6%. The resulting fibers exhibit bulky, flexible, and hydrophobic character.

Example  C TENCEL (Sample 12)

7 g of the finely dried tencel fibers, with the soft finish removed by alcohol, were immersed in 100 ml of an aqueous solution of Hydroresà (liquid ratio 1:15) containing 0.07 g of AKD (1% AKD for cellulose) at room temperature. After 30 minutes of agitation, the fibers were centrifuged to a moisture content of 50% and dried in a drying cabinet at 70 DEG C to a moisture content of 6%. The resulting fibers exhibit bulky, flexible, and hydrophobic character.

Example  D TENCEL (Samples 10 and 11)

14 g of non-dried tencel fibers moistened from the pretreatment lyocell preparation were compressed to a moisture content of 50%, and a solution of Hydrores © prepared from 0.035 g of AKD (0.5% of AKD for cellulose) at room temperature Aqueous solution (approximate liquid ratio 1:15). After 30 minutes of agitation, the fibers were centrifuged to a moisture content of 50% and dried in a drying cabinet at 70 DEG C to a moisture content of 6%. The resulting fibers are bulky, flexible, and exhibit hydrophobic properties.

Example  E obscurity (Samples 14 and 15)

7 g of finely dry bleached cotton fibers, in which any soft finish had previously been removed with alcohol, were immersed in an aqueous solution (liquid ratio 1:15) containing 0.035 g of AKD (0.5% of AKD for cellulose) at room temperature . After 30 minutes of agitation, the fibers were centrifuged to a moisture content of 50% and dried overnight at 70 < 0 > C in a dryer. The obtained cotton fibers are water repellent and very flexible.

Table 1 summarizes the fiber samples according to Examples A to E.

Table 1: Overview of fiber samples

Sledge  exam( sledge test ):

The flexibility of the fibers was measured by the sledge test described in EN 1202 PPS. Important components of this test are:

5 g fiber samples were collected and carded twice using, for example, an MTDA-3 Rotorring apparatus. The fibers were conditioned according to the EDANA manual (ERT 60.2-99) for at least 24 hours and cut into pieces using a master plate. These materials were placed in a testing machine, loaded with sledge (weighing 2,000 g), and stacked on a sample. These tests were started and a measurement of the force required to draw the sledge after 10 seconds was recorded.

The more flexible the fiber surface, the less force required to pull the sledge forward. In order to compare the flexibility of the various samples, the ratio of the force to pull the treated fibers relative to the force to pull a similar merchandise sample or a similar merchandise sample from which the soft finish had been removed was calculated. For example, in Table 2, it can be seen that the flexibility of the viscose fibers treated with the hydrophobing agent is 2.23 times higher than the equivalent commercially available product.

Table 2: Typical commercial fibers Sledge exam  result

In the second series of tests, non-dried cellulose fibers were treated with lower concentrations of AKD (Table 3):

Table 3: Lower concentrations of AKD In Sledge exam  result

These test results show that even cellulose fibers treated with a low level of hydrophobing agent have a flexibility of about 1.7 to 2 times greater than commercial artificial cellulose fibers that are about 2 to 2.5 times larger and equivalent to untreated untreated artificial cellulosic fibers . ≪ / RTI >

The results in Table 4 show that treatment with hydrophobing agents is equally effective for bright dull fibers, for fibers with different linear densities, and for fibers with multiple midline cross-sections .

Table 4: Various artificial Cellulose  For fibers Sledge  Test result

In the third series of tests, the effect of hydrophobizing agents on cotton was evaluated (Table 5):

Table 5: Processed anonymous Sledge  Test result

Commercial bleached cotton with added soft finish is more flexible than natural unbleached equivalent, but this is achieved by losing its hydrophobic character. The use of hydrophobing agents also makes it possible to maintain its hydrophobic properties while producing fibers that are 1.4 times more flexible and similar to bleached and finished goods than naturally occurring products.

Such materials may be fabricated into all nonwoven techniques of the art, including, for example, needle punching, spunlacing and air laying. Conventional textile processing paths are also possible.

The fibers of the present invention may be used in other applications, particularly in nonwovens, for example,

In wipes for household wipes with a high flexibility and bulk biodegradable wipe or improved delicatable properties,

For tampon, especially tampon cover stock or string applications with high flexibility and low friction,

In the medical field, for example for blood and lyophobic cover sheets and drapes, or gowns and facial mask applications,

In the technical field, for example for automotive interiors, hydrophobic layers in car seats, geo textile and agricultural textiles, for filtration, in particular for oil or fat removal, In water, and as reinforcing fibers,

In textile applications, home textiles, such as, for example, fills, padding and bedding, duvets, comforters, pillows, mattresses, disposable blanket in single use blanket, in sports, in wool, especially on both sides to have greater flexibility), animal clothing and bedding.

Nonwoven fabric

Another object of the present invention is to provide a nonwoven fabric exhibiting lower bulk density and higher flexibility desired in various applications. The treated fibers can be processed using the latest nonwoven technologies, for example, needle punches, spun lace, and air laid. In particular, since the chemical bond between AKD and the regenerated cellulose fibers is too strong, the treated fibers can withstand relatively severe spun racing process conditions.

The nonwoven webs and fabrics according to the invention are characterized in that they contain the hydrophobic cellulose fibers according to the invention. Such fabrics can be made by blending hydrophobic cellulose fibers alone or in combination with any other fibers used in rayon, tencel, polyester or nonwoven production.

In order to demonstrate the advantages of the present invention in terms of fabric properties, a range of samples have been produced using both needle punching and spun laced techniques, which are based on flexural strength and flexibility using Handle-o-meter testing Elasticity, and bulk density. Needle punched fabrics were made on a pilot line made by Tec Tex (Italy), and both sides were needle punched with needle punches in the range of 100 to 200 per unit and had a thread depth of 60 gsm with a needle depth of 16 to 18 mm Gram) or 120 gsm fabric. The spun lacing fabric was prepared with a basis weight of 55 gsm in NIRI on a pilot plant.

Flexural strength was tested for bending length according to EDANA WSP 90.5 (05). In this test, one end of the strip of fabric was secured, the other end was left free and supported on a horizontal platform. The strip of fabric is advanced over the edge of the platform until the leading edge of the test specimen reaches the plane of progression through the edge of the platform and tilts at an angle of 41.5 degrees below the horizontal plane. At this point, the protrusion length is equal to twice the bending length of the test specimen, and the bending length can be calculated accordingly. Flexural strength was measured for both the front and back sides of the fabric in four directions, i.e. MD (machine direction) and CD (cross direction), according to the WSP method. These values were averaged and compared to fabrics of similar weight made from untreated fibers.

The Handle-O-Meter test was performed according to WSP 90.3.0 (05). In this test, the nonwoven fabric to be tested was deformed through a limited opening by a plunger and the required force was recorded. The lower the required force, the more flexible and more elastic the fabric. Bulk density was calculated from the area weight [WSP 130.1 (05)] and thickness [WSP 120.6 (05)] according to the EDANA method.

For all tests, the results were normalized to the relevant control for fabrics made from untreated fibers and then expressed as a percentage. For all tests, a percentage result lower than 100 indicates a lower bending length, a lower bending strength, a lower force required in the Handle-O-Meter test, or a lower bulk density, and thus a thicker It shows improvement of properties such as fabric. The results can be seen in Tables 6, 7 and 8.

You guys  Of punching fabric Example :

Example  F:

Non-dried viscose fibers 1.7 dtex / 40 mm were treated with 0.5% AKD solution according to Example B. The dried fibers were processed to form a fabric having nominal weights of 60 gsm and 120 gsm.

Example  G:

Non-dried Tencel fibers 1.7 dtex / 38 mm were treated with 0.5% AKD solution according to Example D. The dried fibers were processed in a needle punch pilot plant to form a fabric having nominal weights of 60 gsm and 120 gsm.

Table 6 shows the flexibility / stretch results for the needle punch fabric according to Examples F and G. < tb > < TABLE >

In all cases, the use of treated fibers results in 17 to 61% more flexible / more elastic fabrics compared to fabrics made from standard untreated fibers. There is a good correlation between the flexural strength and the Handle-O-Meter test.

Table 6: Needle punch  Flexibility / Stretch results for fabrics

Spun lace  Fabric Example :

The fibers prepared according to Samples B and D were converted on a spunlaced pilot plant and processed to form a fabric nominally having a basis weight of 55 gsm. 100% fabrics and blends of fabrics and commercially available viscose and tencel were prepared. Tables 7 and 8 show the effect on fabric flexibility when measured with Handle-O-Meter. The use of treated fibers provides a 50% or better improvement in flexibility compared to 100% treated fibers and has a very significant effect on fabric flexibility and stretchability as measured by Handle-O-Meter.

Table 7: 55 gsm  Viscose Spun lace  Flexibility / Stretch results for fabrics

The addition of even a small blend percentage of treated fibers also has a considerable effect on fabric flexibility when measured by Handle-O-Meter and increases flexibility as the blend percentage increases (Table 8):

Table 8: 55 gsm TENCEL / Treated viscose blend Spun lace  Flexibility / Stretch results for fabrics

Fabrics made from treated fibers will exhibit lower bulk densities than fabrics made from the same untreated fibers and will typically be able to provide the same thickness with a basis weight reduction of 10% in needle punch fabrics (Table 9).

Table 9: Needle punch  Bulk density of fabric:

When the treated fibers are used as 100% substitutes for the same untreated fiber, the bulk density is reduced by more than 25% (Table 10):

Table 10: 55 gsm Spun lace  Bulk density of fabric

A low blend of treated fibers lowered to 5% reduces the bulk density of the fabric (Table 11):

Table 11: 55 gsm TENCEL Spun lace  Effect of Minimum Blend of Treated Fibers on Bulk Density of Fabrics

Overall, the nonwoven fabric according to the present invention exhibits increased flexibility and is characterized in that the bending strength (stiffness) of the nonwoven fabric is at least 15% to as high as 49% lower than the stiffness of the nonwoven fabric made of untreated fibers of similar resistance.

It has also been found that the nonwoven fabric according to the present invention reduces the bulk density by up to 25% in the case of fabrics made from 100% treated fibers, resulting in lower bulk densities compared to untreated fibers under the same conditions.

As a hydrophobic agent  Treated Cellulose  Web or fabric

It is also possible to treat the provided standard artificial cellulose fibers or cellulosic fabrics made from bleached cotton with a hydrophobing agent, but first any soft finish on the fabric is removed. In the case of a spunlaced fabric, the soft finish removal may be achieved by the spun lacing process itself or in a subsequent separate removal step. This process is useful when completely hydrophobic fabrics are required.

Example  H:

A standard commercial Tencel, or a spunlaced fabric produced from a standard commercial viscose sample, was placed in a 0.1% AKD 2 solution and stirred. After 5 minutes, the sample is taken out, weighed, and placed in a drying cabinet at 70 ° C until dry. The obtained fabric is completely water-repellent and flexible. Flexibility was measured in comparison with untreated fabrics using the Handle-O-Meter method described above, and the results are shown in Tables 12 and 13. The flexibility of the fabric treated with the hydrophobing agent is about 50% of the flexibility for a standard untreated spun lace fabric.

Table 12: Handle -O- Meter : As a hydrophobic agent  Treated Spun lace  Viscose fabrics

Table 13: Handle -O- Meter : As a hydrophobic agent  Treated Spun lace TENCEL  textile

Biodegradability / Compostability ( Compostability ):

Needle punch fabrics made from fibers treated with a hydrophobizing agent (selected from those used for evaluating flexibility and bulk density - see Tables 6 and 9) were cut into pieces of approximately 3 x 4 cm, metered, In the soil. Samples were taken after 2 weeks, 1 month and 2 months and weighed to check biodegradation levels. All samples were completely degraded after 2 months. The results are shown in Table 14.

Testing according to ASTM D 6400 (or DIN EN ISO 14855 or DIN EN 14046) is said to be biodegradable if all of the organic compounds are also decomposed into different chemical structures, which are also natural metabolites. This must occur during organic composting. Nonwovens made of viscose and lyocell fibers (commercially available and treated with AKD 2) meet these parameters.

Table 14: Weight reduction of sample vs. soil burial time

Claims (20)

A cellulosic artificial fiber comprising a hydrophobic agent wherein the softness of the fiber as measured by a sledge test is at least 1.3 times greater than the softness of the untreated fiber of the same type, A cellulose artificial fiber characterized by being an alkyl ketene dimer (AKD) according to the following formula (1): < EMI ID =

Wherein R1 and R2 are hydrocarbon groups having 8 to 40 carbon atoms, both of which may be saturated or unsaturated, linear or branched. delete delete The artificial fiber of claim 1, wherein the flexibility of the fibers measured by the sledge test is at least 1.8 times greater than the flexibility of the unfinished fibers of the same type. delete The artificial fiber of cellulose according to claim 1 or 4, wherein the hydrophobing agent is a substituted cyclic dicarboxylic acid anhydride. The artificial fiber of cellulose according to any one of claims 1 to 4, characterized in that it can contain substances which are incorporated with fibers or can be chemically modified. A nonwoven fabric comprising the cellulose artificial fibers according to claims 1 or 4, characterized in that when the flexibility of the nonwoven fabric is subjected to flexural rigidity or Handle-O-Meter test, a nonwoven fabric of the same type of untreated fibers Wherein the nonwoven fabric is at least 15% more flexible than the nonwoven fabric. A nonwoven fabric containing cellulose artificial fibers according to any one of claims 1 to 4 which is biodegradable. A nonwoven fabric comprising the cellulose artificial fibers according to claims 1 or 4, characterized in that the nonwoven fabric is produced by any nonwoven processes in the field. A nonwoven fabric comprising cellulose artificial fibers, or cellulose artificial fibers according to any one of claims 1 to 4 blended with synthetic fibers. The artificial fiber of claim 1 or 4, for use as a nonwoven fabric, in a textile, and as a fill material. 13. The method of claim 12, further comprising the step of applying a wipe, tampon, blood and lyophilic cover sheet and drape, gown and face mask application, geo textile, Cellulose artificial fibers for use in bedding. a) providing a cellulose artificial fiber having a non-modified surface; and
b) A method of producing a cellulose artificial fiber having hydrophobic properties characterized by treating the cellulose artificial fiber with a hydrophobing agent,
Wherein the hydrophobicizing agent is an alkylketene dimer (AKD) according to the following formula (1): < EMI ID =

Wherein R1 and R2 are hydrocarbon groups having 8 to 40 carbon atoms, both of which may be saturated or unsaturated, linear or branched. 15. The method of claim 14, wherein the non-modified surface of the cellulose artificial fiber is a surface of a never-dried fiber. 15. The method of claim 14, wherein the non-modified surface of the cellulose artificial fiber is a surface of finished fiber from which the finish has been removed. delete delete delete 17. A method according to any one of claims 14 to 16, characterized in that the cellulose artificial fibers are treated with a hydrophobicizing agent in a concentration range of 0.0001% to 10% based on the cellulose artificial fibers.