JP2019065443A - Water repellent recycled cellulose fiber, manufacturing method therefor and fiber structure containing the same - Google Patents

Abstract

To provide a water repellent recycled cellulose fiber having water repellency with high durability by a non-fluorine-based water repellent, and suppressing deterioration of cellulose, a manufacturing method therefor and a fiber structure containing the same.SOLUTION: There is provided a water repellent recycled cellulose fiber having water repellency, containing a compound containing one or more acidic group selected from a carboxyl group and a sulfonic acid group, in which an isocyanate compound and a non-fluorine-based water repellent are bound to a fiber surface, the water repellent recycled cellulose fiber has whiteness of Hw 80 or more, or the water repellent recycled cellulose fiber has wet dry Young modulus ratio represented by the following formula (1) with apparent Young modulus at standard time to apparent Young modulus at wet measured according to JIS L 1015 of 12 or more. Wet dry Young modulus=(apparent Young modulus at wet/apparent Young modulus at standard time)×100 (1).SELECTED DRAWING: None

Description

  The present invention relates to a water repellent regenerated cellulose fiber having water repellency, a method for producing the same, and a fiber structure containing the same.

  Conventionally, synthetic fibers having water repellency, such as polyester fibers, have been widely used for the top sheet of sanitary materials such as sanitary napkins and paper diapers. In recent years, the demand for biodegradable and environmentally friendly materials has increased.

  On the other hand, regenerated cellulose fibers such as rayon fibers have biodegradability, but are not suitable for applications requiring water repellency because they do not have water repellency. Therefore, studies have been conducted to impart water repellency to cellulose fibers. For example, in patent document 1, water and cellulose fiber are put into a container, isocyanate and a fluorine resin are put, and it heats to 100-180 degreeC, and makes a cellulose fiber crosslink-bond a fluorine resin to cellulose fiber. It has been proposed to impart water repellency. Patent Document 2 proposes that a cellulose fiber material is treated with a compound that reacts with hydroxyl groups and then treated with a fluorine-based water repellent to impart water repellency to the cellulose fiber material.

JP 2002-266241 A JP 2003-20570 A

  However, when the heat treatment is carried out at a temperature of 130 ° C. or more during the water repelling process, there is a problem that the cellulose is deteriorated. In addition, it is required to use a fluorine-free water repellent agent from the viewpoint of environment and safety.

  In order to solve the above-mentioned conventional problems, the present invention comprises a water repellent regenerated cellulose fiber which has high durability water repellency by a non-fluorine water repellent and in which deterioration of cellulose is suppressed, a method for producing the same, and Providing a fiber structure.

  The present invention is a water-repellent regenerated cellulose fiber having water repellency, wherein the water-repellent regenerated cellulose fiber comprises a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group, which is a fiber The present invention relates to a water repellent regenerated cellulose fiber characterized in that an isocyanate compound and a non-fluorine repellent are bonded to the surface, and the water repellent regenerated cellulose fiber has a whiteness of Hw 80 or more.

The present invention is also a water-repellent regenerated cellulose fiber having water repellency, wherein the water-repellent regenerated cellulose fiber comprises a compound containing one or more acidic groups selected from the group consisting of carboxyl groups and sulfonic acid groups. An isocyanate compound and a non-fluorinated water repellent are bonded to the fiber surface, and the water repellent regenerated cellulose fiber has an apparent Young's modulus as a standard time with respect to an apparent Young's modulus when wet measured according to JIS L 1015. The water-repellent regenerated cellulose fiber is characterized in that a wet-dry Young's modulus ratio represented by the following formula (1) is 12.0 or more.
Wet dry Young's modulus ratio = (Aspect Young's modulus when wet / Apparent Young's modulus when standard) × 100 (1)

  The present invention also relates to the method for producing a water-repellent regenerated cellulose fiber, wherein a viscose stock solution containing cellulose is a compound containing one or more acidic groups selected from the group consisting of carboxyl groups and sulfonic acid groups. The mixture is mixed to prepare a viscose solution for spinning, and the viscose solution for spinning is extruded from a nozzle and coagulated and regenerated to make viscose rayon yarn, and the viscose rayon yarn is an isocyanate compound and non-fluorinated water repellent The present invention relates to a method for producing a water repellent regenerated cellulose fiber, which is treated with a water repellent treatment liquid containing an agent and heat treated so that the fiber surface has a temperature of 40 ° C. or more and 110 ° C. or less.

  The invention also relates to a fiber structure comprising water repellent regenerated cellulose fibers.

  According to the present invention, it is possible to provide a water-repellent regenerated cellulose fiber having high durability and water repellency by a non-fluorinated water repellent, and in which deterioration of cellulose is suppressed, and a fiber structure including the same.

  According to the present invention, it is possible to obtain a water-repellent regenerated cellulose fiber having high durability and water repellency by a non-fluorine-based water repellent, and in which deterioration of cellulose is suppressed.

FIG. 1 is a schematic explanatory view showing the contact angle with water in the non-woven fabric.

  The inventor of the present invention includes a compound containing at least one acidic group selected from the group consisting of a carboxyl group and a sulfonic acid group in regenerated cellulose fiber such as rayon fiber, and an isocyanate compound and non-fluorinated water repellent Heat treatment so that the fiber surface has a low temperature of 40 ° C. or more and 110 ° C. or less, while suppressing deterioration of cellulose, the water repellant property of the regenerated cellulose fiber is high. It has been found that it is possible to give The suppression of the deterioration of the cellulose can be confirmed by measuring the whiteness of the regenerated cellulose fiber or the wet dry Young's modulus ratio described later. When the whiteness of the regenerated cellulose fiber is Hw 80 or more, the deterioration of the cellulose is suppressed. Alternatively, when the wet-dry Young's modulus ratio of the regenerated cellulose fiber is 12.0 or more, the deterioration of the cellulose is suppressed. Note that heat treatment to bring the fiber surface to a temperature of 40 ° C to 110 ° C is not the set temperature of the heat treatment machine, but the temperature actually applied to the fiber surface (also referred to as the actual temperature) is 40 ° C to 110 ° C. It means to heat-process on the following temperature conditions. The actual temperature can be measured using a known contact surface thermometer, non-contact surface thermometer, thermography or the like.

Specifically, a regenerated cellulose fiber such as rayon fiber contains a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group, and contains an isocyanate compound and a non-fluorinated water repellent By using the treatment liquid for water-repellent treatment, the acid group and the isocyanate compound are bonded on the surface and inside of the fiber, and the acid group acts as an acid catalyst, whereby the isocyanate group and water react efficiently. Produces an amine. Since the generated amine causes various side reactions, it is presumed that the fixing property of the non-fluorinated water repellent on the fiber surface is improved even when the heat treatment is performed so that the fiber surface has a low temperature of 40 ° C to 110 ° C. For example, the following reaction is expected to occur between a carboxyl group, an isocyanate group, and a non-fluorinated water repellent (for example, a hydrocarbon-based water repellent mainly composed of an acrylic resin).
COOH + NCO + H ₂ O → NH ₂ (Amine formed)
COOH + NCO → NHCO (amide formed)
NH ₂ + NCO → NH CONH (urea is formed)
NH ₂ + COO → NH (OH) CO
NH ₂ + COOH → NHCO (amide is formed)

  The water repellent regenerated cellulose fiber contains a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group. In the following, unless otherwise specified, the “compound containing an acidic group” means a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group. A compound containing an acidic group in the fiber is prepared by spinning a viscose solution for spinning prepared by mixing a compound containing an acidic group with a viscose stock solution at the time of preparation of regenerated cellulose fiber, an acidic group Immersing the regenerated cellulose fiber in an aqueous solution containing a compound containing the acid to impregnate the fiber with a compound containing an acidic group, spraying or applying an aqueous solution containing a compound containing an acidic group to the regenerated cellulose fiber A compound containing an acidic group can be included in the regenerated cellulose fiber by attaching a compound containing an acidic group to the regenerated cellulose fiber. Among them, kneading is preferable because the compound having an acidic group is uniformly mixed and dispersed throughout the surface and the inside of the fiber.

  The compound containing a carboxyl group is not particularly limited, but for example, from the viewpoint of easily giving a carboxyl group to a regenerated cellulose fiber, one or more selected from the group consisting of polyacrylic acid and acrylic acid-maleic acid copolymer Is preferred.

  As the polyacrylic acid, for example, it is preferable to use an unneutralized product of polyacrylic acid, that is, the H-type of polyacrylic acid in which the carboxyl group of the polyacrylic acid is in the H-type. In addition, the site | part of H of the carboxyl group of polyacrylic acid may be partially substituted by metal ions, such as Na, or an ionic compound. In the following, polyacrylic acid means non-neutralized polyacrylic acid unless otherwise specified. As said polyacrylic acid, it is the structure which the carboxyl group attached to the principal chain as a main, and the contribution of the carboxyl group with respect to the molecular weight of polymer | macromolecule can use the largest compound, for example, the quantity of theoretical carboxyl group is 72g / mol. It is preferable to use the above polyacrylic acid.

  The acrylic acid-maleic acid copolymer is an ethylenically unsaturated monomer containing at least one selected from the group consisting of acrylic acid and acrylic acid (hereinafter also referred to as an acrylic acid-based monomer). And a polymer of an ethylenically unsaturated monomer containing at least one selected from the group consisting of maleic acid, maleic acid salt and maleic anhydride (hereinafter also referred to as a maleic acid based monomer). A polymer of an ethylenically unsaturated monomer comprising at least one member selected from the group consisting of acrylic acid and acrylate and at least one member selected from the group consisting of maleic acid, maleate and maleic anhydride It may be In addition, from the viewpoint of easily imparting a carboxyl group to the fiber, the acrylic acid-maleic acid copolymer comprises an ethylenically unsaturated monomer containing at least one selected from the group consisting of acrylic acid and acrylic acid salts, and maleic acid. A polymer of an ethylenically unsaturated monomer containing at least one selected from the group consisting of an acid and a maleate, and / or at least one selected from the group consisting of an acrylic acid and an acrylate, and maleic acid It is preferable that it is a polymer of the ethylenically unsaturated monomer containing at least 1 sort (s) chosen from the group which consists of and a maleate salt. In addition, if necessary, the acrylic acid-maleic acid polymer is copolymerized with other monomers than acrylic acid monomers and maleic acid monomers within the range that does not impair the effects of the present invention. It may be The other monomer may be, for example, an unsaturated monocarboxylic acid monomer.

  The weight average molecular weight of the acrylic acid-maleic acid copolymer is preferably 5,000 or more and 500000 or less, more preferably 6,000 or more and 250,000 or less, and still more preferably 10,000 or more and 100,000 or less, and 30,000 or more and 80,000. It is particularly preferred that When the weight average molecular weight is in the above-mentioned range, it is easy to knead in regenerated cellulose, and even when washed or dyed / washed, it is difficult for dropout or denaturation of the compound containing a carboxyl group to occur.

  The acrylic acid-maleic acid copolymer preferably contains 5% by mass or more and 95% by mass or less of maleic acid, more preferably 20% by mass or more and 80% by mass or less, and contains 30% by mass or more and 70% by mass or less Is more preferable, and it is particularly preferable to include 40% by mass or more and 60% by mass or less. When the content of maleic acid in the acrylic acid-maleic acid copolymer is in the above range, it is easy to give a carboxyl group to the regenerated cellulose fiber. When the same mass of acrylic acid-maleic acid copolymer is contained in the regenerated cellulose fiber, inclusion of acrylic acid-maleic acid copolymer having a high maleic acid ratio also increases the amount of H-type carboxyl group. Because it is preferable.

In the present invention, the ratio of maleic acid in the acrylic acid-maleic acid copolymer is measured and calculated as follows, assuming that the organic component in the acrylic acid-maleic acid copolymer is only acrylic acid and maleic acid. can do.
(1) Place about 4 to 5 mL of a sample (an aqueous solution containing an acrylic acid-maleic acid copolymer salt) in a glass vial, and heat at 110 ° C. for 20 hours to dry.
(2) Dissolve about 50 mg of a dry sample in about 0.7 mL of heavy water.
(3) 1 H-NMR analysis is performed on a heavy aqueous solution of a sample using an FT-NMR apparatus (JMTC-300 / 54 / SS, manufactured by Nippon Denshi Co., Ltd.), and methylene carbon and methine in the polymer main chain The composition ratio of the acrylic acid component (A) and the maleic acid component (M) is determined from the abundance ratio of the base carbon. The number of measurements is 16 and the average value is determined.

  The compound containing a sulfonic acid group is not particularly limited. For example, naphthalene sulfonic acid salt, polystyrene sulfonic acid salt, phenol sulfonic acid salt, dihydroxydiphenyl sulfone, formalin condensate of hydroxyphenyl sulfone, and the like can be used.

  In the water-repellent regenerated cellulose fiber, the content of the compound containing one or more acidic groups selected from the group consisting of the carboxyl group and the sulfonic acid group is, for example, 1% by mass to 35% with respect to 100% by mass of cellulose. % Or less, preferably 3% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 25% by mass or less. In the water-repellent regenerated cellulose fiber, if the content of the compound having one or more acidic groups selected from the group consisting of the carboxyl group and the sulfonic acid group is less than 1% by mass with respect to 100% by mass of cellulose, the acid group If the content exceeds 35% by mass, the fiber strength may be reduced, and the fineness may not be achieved.

  In the water repellent regenerated cellulose fiber, the total amount of one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group is preferably 0.30 mmol / g or more and 1.60 mmol / g or less, more preferably 0. It is not less than .35 mmol / g and not more than 1.50 mmol / g, and more preferably not less than 0.40 mmol / g and not more than 1.40 mmol / g. When the total amount of one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group is in the above-mentioned range, the effect by the acidic group is easily exhibited. In the water-repellent regenerated cellulose fiber, as described above, the acid group is a non-fluorinated water repellent fiber even when heat treatment is performed such that the isocyanate compound is bonded and the fiber surface has a low temperature of 40 ° C to 110 ° C. While improving the fixability of the surface, it exerts the effect of imparting ammonia deodorizing property and pH buffer property to the regenerated cellulose fiber. In the present invention, the total amount of one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group is measured and calculated as described later.

  The non-fluorinated water repellent is not particularly limited, but, for example, a hydrocarbon water repellent is preferable. As the hydrocarbon-based water repellent, for example, a hydrocarbon-based water repellent comprising a polymer containing, as a basic unit of a monomer, a (meth) acrylic acid ester having a carbon number of 12 or more of a hydrocarbon group present via an ester bond It is preferable to use a solution. The carbon number of the hydrocarbon group is more preferably 24 or less, still more preferably 21 or less. The hydrocarbon group may be linear or branched, may be a saturated hydrocarbon or an unsaturated hydrocarbon, and further has an alicyclic or aromatic ring. It may be done. Among these, linear ones are preferable, and linear alkyl groups are more preferable. In the present specification, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester.

  It is preferable that the said (meth) acrylic acid ester monomer is 80 to 100 mass% with respect to the whole quantity of the monomer unit which comprises the said polymer. The weight average molecular weight of the hydrocarbon-based water repellent is preferably 100,000 or more, and more preferably 500,000 or more. The hydrocarbon-based water repellent may be a copolymer of an acrylic ester and a methacrylic ester.

  The hydrocarbon-based water repellent can be used as a water repellent composition in which hydrocarbon-based water repellent particles are dispersed in water. The water repellent composition may contain a surfactant and an organic solvent. As such a water repellent composition, for example, a commercial product such as Neoseed NR series (manufactured by Nikka Chemical Co., Ltd.) may be used.

  In the water repellent regenerated cellulose fiber, the adhesion amount of the non-fluorinated water repellent is, for example, preferably 0.1% by mass to 10% by mass with respect to 100% by mass of cellulose, and 0.2% by mass The content is more preferably 8% by mass or less, still more preferably 0.3% by mass to 6% by mass, and still more preferably 0.5% by mass to 2% by mass. When the adhesion amount of the non-fluorine-based water repellent agent is within the above range, the water repellency is improved and the fiber is less likely to be rigid.

  The non-fluorinated water repellents may be used alone or in combination of two or more.

  As said isocyanate type compound, crosslinking agents, such as a compound which has an isocyanate group, and a compound which has a blocked isocyanate group, can be used, for example. The isocyanate compound is

  Examples of compounds having an isocyanate group include monoisocyanates such as butyl isocyanate, phenyl isocyanate, tolyl isocyanate and naphthalene isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, tetramethyl xylylene diisocyanate, diisocyanates such as hydrogenated diphenylmethane diisocyanate, and these isocyanurate rings. And trimerol, and trimethylolpropane adduct.

  As a compound which has a blocked isocyanate group, the compound which protected the isocyanate group with the compound which has the said isocyanate group with a blocking agent is mentioned. As the blocking agent used at this time, an organic blocking agent such as secondary or tertiary alcohols, active methylene compounds, phenols, oximes, lactams, and bisulfite such as sodium bisulfite and potassium bisulfite Salt etc. are mentioned. The blocked isocyanate group is masked with a highly reactive isocyanate group, and the block is usually dissociated by heat treatment at 120 to 180 ° C. In the present invention, cellulose is selected from the group consisting of carboxyl group and sulfonic acid group in cellulose. Since it has one or more acid groups to be selected, it is estimated that the block dissociates at a low temperature of 40 ° C. or more and 110 ° C. or less. Therefore, the blocked isocyanate group is present in a dissociated state of the block on the surface of the water repellent regenerated cellulose fiber.

  In the water-repellent regenerated cellulose fiber, the adhesion amount of the isocyanate compound is, for example, preferably 0.010% by mass or more and 5.0% by mass or less with respect to 100% by mass of cellulose, and 0.020% by mass or more It is more preferably 3.0 mass% or less, still more preferably 0.03 mass% or more and 2.0 mass% or less, and still more preferably 0.05 mass% or more and 1.0 mass% or less preferable. When the adhesion amount of the non-fluorinated water repellent agent is within the above range, the durability of the water repellency (hereinafter also referred to as durable water repellency) is improved, and the fibers are less likely to be rigid.

  The said isocyanate type compound may be used individually by 1 type, and may be used combining 2 or more types suitably.

  The mass ratio of the non-fluorinated water repellent to the isocyanate compound (non-fluorinated water repellent: isocyanate compound) is not particularly limited, but, for example, from the viewpoint of improving water repellency and its durability, 3: It is preferably 1 or more and 7: 1 or less, and more preferably 4: 1 or more and 6: 1 or less.

  The water repellent regenerated cellulose fiber is not particularly limited, and, for example, a viscose stock solution containing cellulose (raw material viscose), a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group The mixture is mixed to prepare a viscose solution for spinning, and the viscose solution for spinning is extruded from a nozzle and coagulated and regenerated to make viscose rayon yarn, and the viscose rayon yarn is an isocyanate compound and non-fluorinated water repellent It can manufacture by heat-processing so that the fiber surface may become the temperature of 40 degreeC or more and 110 degrees C or less, after processing with the processing liquid for water-repellent processing containing an agent.

  The raw material viscose may contain, for example, 7% by mass to 10% by mass of cellulose, 5% by mass to 8% by mass of sodium hydroxide, and 2% by mass to 3.5% by mass of carbon disulfide. At this time, if necessary, additives such as ethylenediaminetetraacetic acid (EDTA) and titanium dioxide can also be used. The temperature of the raw material viscose is preferably maintained at 18 ° C. or more and 23 ° C. or less.

  The addition amount of the compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group is 1% by mass or more and 35% by mass or less with respect to 100% by mass of cellulose in the raw material viscose The content is preferably 3% by mass to 30% by mass, and more preferably 5% by mass to 25% by mass. Within the above-described range, a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group can be effectively kneaded into the fiber while increasing the fiber strength.

  The viscose rayon yarn can be manufactured, for example, using a conventional circular nozzle. As the spinning nozzle, although depending on the target production amount, it is preferable to use a circular nozzle having a diameter of 0.05 mm or more and 0.12 mm or less and a number of holes of 1000 or more and 20000 or less. Alternatively, nozzles of different cross section may be used. The viscose solution for spinning is extruded into a spinning bath and spun using the spinning nozzle to coagulate and regenerate. The spinning speed is preferably in the range of 30 m / min to 80 m / min. The stretching ratio is preferably 39% or more and 55% or less. Here, when the sliver speed before stretching is 100, the stretch ratio indicates how fast the sliver speed after stretching is. The ratio before stretching is 1 and after stretching is 1.39 or more and 1.55 or less.

  As a spinning bath (Muller bath), for example, a strong acid containing 95 g / L to 130 g / L of sulfuric acid, 10 g / L to 17 g / L of zinc sulfate, and 290 g / L to 370 g / L of sodium sulfate (sodium sulfate) It is preferred to use a sexing bath. The more preferable sulfuric acid concentration is 95 g / L or more and 120 g / L or less.

  The viscose rayon yarn (regenerated cellulose fiber) obtained as described above is cut into a predetermined length and usually subjected to a scouring treatment. The scouring process can be generally performed in the order of hot water treatment, water washing, water sulfidation treatment (desulfurization), bleaching, acid washing and water washing. Bleaching and acid washing may be omitted.

  If necessary, the rayon fiber yarn after the scouring step may be pH-adjusted to adjust the pH of the fiber to 8.0 or less. The pH adjustment treatment can be performed by immersing the fiber in a buffer having a pH of 6.0 or less. The bath ratio during immersion is not particularly limited, but is preferably 1:10 or more and 1:30 or less, more preferably 1:15 or more and 1:25 or less. The immersion time is not particularly limited, but is preferably 0.5 minutes to 50 minutes, and more preferably 1 minute to 20 minutes. The pH adjusting buffer is not particularly limited. For example, although it is possible to use a general buffer solution such as acetic acid-sodium acetate buffer, it is preferable that the buffer solution contains sodium. . After being immersed in a pH adjustment buffer solution, it may be washed with water and dried.

  The amount of H-type carboxyl group and / or H-type sulfonic acid group is preferably 0.20 mmol or more and 1.60 mmol / g or less, and more preferably 0.30 mmol or less in the regenerated cellulose fiber (before water repellent treatment). / G or more and 1.50 mmol / g or less, more preferably 0.35 mmol / g or more and 1.40 mmol / g or less. In the regenerated cellulose fiber, the amount of the salt type carboxyl group and / or the salt type sulfonic acid group is preferably 1.0 mmol / g or less, more preferably 0.35 mmol / g or less, and further preferably It is 0.015 mmol / g or more and 0.20 mmol / g or less.

  In the regenerated cellulose fiber (before water repellent treatment), the ratio of the amount of H-type carboxyl group and / or H-type sulfonic acid group to the total amount of carboxyl group and / or sulfonic acid group is 45% or more and 100% or less Is more preferably 80% or more and 98% or less, and still more preferably 90% or more and 95% or less. When the ratio of the amount of the H-type carboxyl group and / or the H-type sulfonic acid group is within the above-mentioned range, the carboxyl group and / or the sulfonic acid group is easily bonded to the isocyanate group in the water repelling process described later A carboxyl group and / or a sulfonic acid group acts as an acid catalyst, and the amine formed by the efficient reaction of the isocyanate group and water is likely to cause various side reactions, and the durable water repellency can be enhanced.

  After the scouring process, water repelling is performed. First, the viscose rayon yarn is treated with a treatment liquid for water repelling treatment containing an isocyanate compound and a non-fluorinated water repellent to adhere the isocyanate compound and the non-fluorinated water repellent. The treatment method with the treatment liquid for water-repellent treatment is not particularly limited, and examples thereof include treatment methods such as immersion, spraying, and shower coating. The treatment with the treatment liquid for water repellant processing is a condition that the moisture content of the viscose rayon yarn is 100% by mass or more and 180% by mass or less from the viewpoint of easy adhesion of isocyanate compound and non-fluorinated water repellent to fibers. The water content is preferably 120% by mass or more and 150% by mass or less.

  The non-fluorinated water repellent and the isocyanate compound are dispersed in a solvent such as water in the treatment liquid for water repellent finishing. The concentration of the non-fluorine-based water repellent in the treatment liquid is not particularly limited, but is preferably 0.15% by mass or more and 40% by mass or less. More preferably, it is 0.35% by mass or more and 35% by mass or less. If the concentration of the treatment liquid is in the above range, the adhesion amount of the non-fluorinated water repellent and the isocyanate compound can be easily adjusted, and the temperature of the fiber surface is adjusted to a low temperature when evaporating a solvent such as water during heat treatment. Easy to do and preferred.

  The use amount of the non-fluorinated water repellent can be appropriately adjusted according to the required degree of water repellency, but the non-fluorinated water repellent (as a water repellent) with respect to 100% by mass of the regenerated cellulose fiber Even when the water repellent composition is used, it is preferable to adjust the non-fluorinated water repellent only) to be 0.1% by mass or more and 10% by mass or less, and 0.2% by mass or more and 8.0 or more. It is more preferable to adjust so that it becomes below in mass%. When the adhesion amount of the non-fluorine-based water repellent agent is within the range described above, it is easy to impart water repellency and, at the same time, the softness of the regenerated cellulose fiber can be maintained.

  The amount of the isocyanate-based compound (for example, a crosslinking agent such as a compound having an isocyanate group and a compound having a blocked isocyanate group) is not particularly limited, but from the viewpoint of easily maintaining the softness of the regenerated cellulose fiber, regenerated cellulose It is preferable that it is 0.010 mass% or more and 5.0 mass% or less with respect to 100 mass% of fibers, and it is more preferable that it is 0.02 mass% or more and 3.0 mass% or less.

  The treatment liquid for water repelling treatment is not particularly limited, but from the viewpoint of enhancing the durable water repellency and maintaining the softness of the regenerated cellulose fiber, the mass ratio of the non-fluorinated water repellent to the isocyanate compound (non The fluorine-based water repellent: isocyanate compound) is, for example, preferably 3: 1 or more and 7: 1 or less, and more preferably 4: 1 or more 6: 1 or less.

  Next, heat treatment is performed so that the fiber surface has a temperature of 40 ° C. or more and 110 ° C. or less. The lower limit of the more preferable actual temperature at the heat treatment temperature (actual temperature) is 50 ° C. or higher for the fiber surface, and the lower limit of the more preferable actual temperature is 60 ° C. or higher for the fiber surface. The upper limit of the actual temperature is more preferably 100 ° C. or less, still more preferably 95 ° C. or less, still more preferably 90 ° C. or less. When the heat treatment temperature is in the above-described range, the isocyanate compound and the non-fluorinated water repellent agent are firmly bonded to the fiber, and the deterioration of the fiber due to heat such as yellowing of the fiber can be suppressed. When the water-repellent treatment liquid contains water, the drying treatment performed to remove water can be heat treatment.

  After the water repelling process, an oil may be added as needed to such an extent that the water repellency does not deteriorate. The water repellent regenerated cellulose fiber may be dyed. The dyeing is not particularly limited, and can be performed by, for example, a general reactive dyeing method or cationic dyeing method of cellulose fiber.

  The water repellent regenerated cellulose fiber is not particularly limited, but preferably has a single fiber fineness of 0.3 dtex or more and 8.0 dtex or less, for example. More preferably, it is not less than 0.6 dtex and not more than 6.0 dtex, and still more preferably, not less than 0.7 dtex and not more than 3.6 dtex. If the single fiber fineness is less than 0.3 dtex, it is likely that single fiber breakage tends to occur during drawing. When the single fiber fineness exceeds 8.0 dtex, the regenerated state of the fiber tends to be poor, and the hue of the fiber may be deteriorated.

  The water repellent regenerated cellulose fiber preferably has a whiteness of Hw 80 or more and Hw 80 or more and Hw 90 or less from the viewpoint of maintaining the texture of cellulose. In the case of general regenerated cellulose fiber, when performing water repellant processing, it is necessary to react the crosslinking agent under conditions of 120 ° C. or more and 170 ° C. or more to improve the water repellant durability, and whitening by exposure to high temperature The degree drops significantly (less than Hw 80). In the present invention, since regenerated cellulose containing a specific acidic group is used, deterioration of cellulose can be suppressed, and as a result, the whiteness tends not to be substantially reduced.

  The water repellent regenerated cellulose fiber preferably has a tensile strength at a standard time (hereinafter also referred to as dry strength) measured according to JIS L 1015 of 1.5 cN / dtex or more and 3.0 cN / dtex or less. More preferably, it is 1.7 cN / dtex or more and 2.7 cN / dtex or less. The wet tensile strength (hereinafter, also referred to as wet strength) is preferably 0.6 cN / dtex or more and 2.0 cN / dtex or less. More preferably, it is 0.8 cN / dtex or more and 1.8 cN / dtex or less.

  The water-repellent regenerated cellulose fiber preferably has an elongation at standard time (hereinafter, also referred to as a degree of dry elongation) measured according to JIS L 1015 of 15% or more and 25% or less. More preferably, it is 16% or more and 24% or less. It is preferable that it is 15% or more and 40% or less in elongation rate at wet (hereinafter, also referred to as wet elongation). More preferably, it is 18% or more and 35% or less.

  When the tensile strength and the elongation are in the above ranges, the spinnability is good and the product strength tends to be good.

  In the case of general regenerated cellulose fiber, when performing water repellant processing, it is necessary to react the crosslinking agent under conditions of 120 ° C. or more and 170 ° C. or more to improve the water repellant durability, and the water repellant by exposing to high temperature Although the film formation and cross-linking of the agent occur strongly, the rigidity and strength of the whole fiber increase at standard time (dry state), but the strength of cellulose itself is lowered due to the deterioration of amorphous part of cellulose by heat . Therefore, in addition to the strength of the cellulose itself decreasing due to swelling with water, breaking of hydrogen bonds in the amorphous part, etc. as in the wet state, the wet strength tends to be significantly reduced due to the influence of heat deterioration. In the present invention, the cellulose has at least one acidic group selected from the group consisting of a carboxyl group and a sulfonic acid group, and can be water-repellent processed at a low temperature of 100 ° C. or less. While the stiffness and strength of the cellulose are increased, the heat damage to the cellulose itself is less, and the decrease in wet strength tends to be less.

  The water repellent regenerated cellulose fiber preferably has an apparent Young's modulus at a standard time (hereinafter, also referred to as a dry Young's modulus (DY)) measured according to JIS L 1015 is 3500 MPa or more and 8500 MPa or less. More preferably, it is 4000 MPa or more and 8000 MPa or less. The apparent Young's modulus (hereinafter also referred to as wet Young's modulus (WY)) when wet is preferably 800 MPa or more and 1300 MPa or less. More preferably, it is 900 MPa or more and 1200 MPa or less. When the apparent Young's modulus is in the above range, appropriate stiffness can be imparted to the fiber while maintaining the softness of the fiber itself.

The ratio of wet / normal time (wet-dry) in apparent Young's modulus is expressed as a factor that causes the water repellent to be firmly bonded while suppressing deterioration of the cellulose itself, and is represented by the following formula.
Wet dry Young's modulus ratio = (WY / DY) × 100 (1)
The apparent Young's modulus indicates the rigidity of the fiber to the initial tension, and the dry Young's modulus (DY) tends to increase due to the combination of the strength of the cellulose itself and the water repellent by crosslinking, but the wet Young's modulus (DY) tends to increase. Young's modulus (WY) tends to decrease rigidity at initial tension due to swelling of cellulose with water and breakage of hydrogen bonds in the noncrystalline part, and the influence of deterioration of the noncrystalline part due to heat tends to be small together It is in. Thus, as in the present invention, by suppressing the deterioration of cellulose, the decrease in WY is suppressed, and as a result, WY / DY tends to be high. WY / DY is preferably 12.0 or more. More preferably, it is 12.5 or more.

  The water repellent regenerated cellulose fiber is preferably 70 degrees or more, and the contact angle with water of the water entangled nonwoven fabric made of 100% by mass of the water repellent regenerated cellulose fiber is preferably 65 degrees or more, from the viewpoint of excellent durability and water repellency. Is more preferably 75 degrees or more, and still more preferably 80 degrees or more.

  The water repellent regenerated cellulose fiber preferably has an ammonia deodorizing rate of 70% or more, more preferably 80% or more, still more preferably 90% or more, and still more preferably, from the viewpoint of excellent deodorizing properties. Is 95% or more. In the present invention, the ammonia deodorization rate is a decrease in ammonia measured by the measurement method defined by the SEK fiber product certification standard (revised on April 1, 2030) of the Japan Fiber Evaluation Technology Council (JTETC). Say the rate.

  The water repellent regenerated cellulose fiber preferably has a pH buffering property in the range of pH 4 to 9, and more preferably a pH buffering property in the range of pH 4 to 10, from the viewpoint of excellent pH buffering property.

  The water repellent regenerated cellulose fibers may be provided in the form of long fibers or short fibers to form a fiber structure. Examples of the long fiber include tow, filament, non-woven fabric, and the like, and examples of the short fiber include raw cotton for wet papermaking, raw cotton for air-laid non-woven fabric, raw cotton for card, and the like.

  The fiber structure is not particularly limited, but preferably contains 10% by mass or more of the water repellent regenerated cellulose fiber, more preferably 20% by mass to 50% by mass, and still more preferably 25% by mass to 40% by mass Including below. When the content of the water-repellent regenerated cellulose fiber is low, it is difficult to exhibit performance such as water repellency, ammonia deodorizing property and pH buffering property by the fiber, and when the content of the water-repellent regenerated cellulose fiber is high, the texture of rayon becomes front Depending on the product, the drapability of the product may damage the tension of the fiber assembly.

  The fiber structure exhibits water repellency by containing the water repellent regenerated cellulose fiber. By heat-treating the fiber structure, it is possible to further improve the water repellency of the water repellent regenerated cellulose fiber, and thus to further improve the water repellency of the fiber structure.

  The fiber structure is not particularly limited, and examples thereof include tow, filament, spun yarn, batting (padding), paper, non-woven fabric, woven fabric, knitted fabric and the like, and it is a spun yarn, non-woven fabric, woven fabric or knitted fabric More preferably, it is a type of fabric selected from the group consisting of knits, wovens and non-wovens.

  When the fiber structure is a woven fabric or a knitted fabric, it may be composed only of the water repellent regenerated cellulose fiber, or may contain other fibers. The regenerated cellulose fiber other than the said regenerated cellulose fiber, a natural fiber, a synthetic fiber etc. are mentioned. Other regenerated cellulose fibers include, for example, rayon, cupra, solvent-spun cellulose, polynosic and the like. Examples of natural fibers include cotton, hemp, wool, silk, pulp and the like. Examples of synthetic fibers include acrylic fibers, polyester fibers, polyamide fibers, polyolefin fibers, polyurethane fibers and the like. The synthetic fiber may be a single fiber or a composite fiber. The structure of the woven or knitted fabric is not particularly limited. For example, in the case of knitting, circular knitting, weft knitting and warp knitting (tricot) are preferred, and in the case of woven fabrics, plain weave, twill weave and satin weave are the preferred form of fiber structure since the texture effect of the present invention can be exhibited well.

  When the fiber structure is a non-woven fabric, it may be composed only of the water repellent regenerated cellulose fiber, or may be mixed with other fibers. The regenerated cellulose fiber other than the said regenerated cellulose fiber, a natural fiber, a synthetic fiber etc. are mentioned. Other regenerated cellulose fibers include, for example, rayon, cupra, solvent-spun cellulose, polynosic and the like. Examples of natural fibers include cotton, hemp, wool, silk, pulp and the like. Examples of synthetic fibers include acrylic fibers, polyester fibers, polyamide fibers, polyolefin fibers, polyurethane fibers and the like. The synthetic fiber may be a single fiber or a composite fiber. Examples of the non-woven fabric include wet non-woven fabric (wet papermaking), air-laid non-woven fabric, water-entangled non-woven fabric, needle punch non-woven fabric, heat-bonded non-woven fabric (air through, heat roll, emboss roll, etc.) and the like.

  Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited to the following examples.

Example 1
[Preparation of viscose solution for spinning]
Aqueous solution of acrylic acid-maleic acid copolymer salt ("Aqualic TL400" manufactured by Nippon Shokubai Co., Ltd., an aqueous solution containing 40% by mass of acrylic acid-maleic acid copolymer having a weight average molecular weight of 50,000, viscosity: 1990 mPa · s, the content of maleic acid in acrylic acid-maleic acid copolymer sodium is 45% by mass), and acrylic acid-maleic acid copolymer salt is 12% by mass with respect to 100% by mass of cellulose, The resultant was added to raw material viscose, stirred and mixed in a mixer to prepare a viscose solution for spinning. The temperature was kept at 20 ° C. The raw material viscose contained 8.5% by mass of cellulose, 5.7% by mass of sodium hydroxide and 2.8% by mass of carbon disulfide. In Examples and Comparative Examples, the viscosity was measured at 20 ° C. using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. Moreover, the weight average molecular weight of the compound containing a carboxyl group was measured and calculated as mentioned later.
[Spinning process]
The obtained viscose solution for spinning was spun at a spinning speed of 60 m / min and a draw ratio of 50% by a two-bath tensor method to obtain a thread of viscose rayon having a fineness of 1.4 dtex. As a first bath (spinning bath), a Mueller bath (50 ° C.) containing 100 g / L of sulfuric acid, 15 g / L of zinc sulfate and 350 g / L of sodium sulfate was used. Moreover, the circular nozzle (hole diameter 0.06 mm, the number of holes 4000) was used for the spinneret which discharges viscose.
[Scouring process]
The yarn of viscose rayon obtained above was cut to a fiber length of 38 mm, washed with water after hot water treatment, and desulfurized by showering with sodium hydrogen sulfide. The treated cotton obtained was washed again with water, bleached with sodium hypochlorite, pickled and then washed with water. Thereafter, the fibers were squeezed by a compression roller so that the moisture content became 130%. In the regenerated cellulose fiber (before water repellent treatment), the ratio of H-type carboxyl group to the total amount of carboxyl group was 93%. The H-type carboxyl group content was 1.00 mmol / g.
[Water-repellent finish]
First, using a hydrocarbon-based water repellent composition ("Neoseed NR-158" manufactured by Nikka Chemical Co., Ltd.) as a non-fluorinated water repellent, a blocked isocyanate-based crosslinking agent (manufactured by Nicha Chemical Co., Ltd.) as an isocyanate-based compound Water-repellant (water-repellent particles): cross-linking agent (solids) in a mass ratio of 5: 1 using “NK Assist NY-30”, solid content concentration 40 mass%) A processing solution for processing was obtained. Next, the fiber having a moisture content of 130% obtained above was immersed in the water-repellent treatment liquid (50 ° C.) for 30 seconds. The bath ratio of the fiber: water repellent treatment liquid was made to be 1:10. Thereafter, the fibers are squeezed by a compression roller so that the adhesion ratio of the water repellent (solid content) to the fibers is 1% by mass, and then subjected to a drying treatment for 2 hours by a dryer set at 60 ° C. Obtained. The actual temperature at this time was 60.degree. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.97 mmol / g.
[Preparation of non-woven fabric]
Fiber A was used to make a random web on a random card machine. The obtained web is passed through a hydroentangling machine, and a high pressure water stream of 3 MPa and 5 MPa is jetted once on each side of the web by a nozzle in which orifices with a nozzle diameter of 0.13 mm are arrayed at 1 mm intervals. A high pressure water flow of 5 MPa was injected once and naturally dried to obtain a nonwoven fabric A having a basis weight, a thickness and a specific volume shown in Table 1.

(Example 2)
Fibers B were obtained in the same manner as in Example 1 except that in the water repelling process, the drying process was performed for 10 minutes with a dryer set at 100 ° C. The actual temperature at this time was 85 ° C. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.97 mmol / g. Moreover, it carried out similarly to Example 1 except having used the fiber B, and obtained the nonwoven fabric B which has a fabric weight shown in Table 1, thickness, and a specific volume.

(Example 3)
In the same manner as in Example 2 except that in the water repellent finish, the fibers were squeezed so that the adhesion ratio of the water repellent and the crosslinking agent (solid content) to the fibers was 0.1% by mass with a compression roller. I got C. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 1.06 mmol / g. Moreover, it carried out similarly to Example 1 except having used the fiber C, and obtained the nonwoven fabric C which has a fabric weight shown in Table 1, thickness, and a specific volume.

(Example 4)
In the scouring process, after bleaching with sodium hypochlorite, pickling and washing with water, it is immersed in a 15% by weight aqueous sodium carbonate solution (20 ° C.) for 10 minutes, and then the fiber is squeezed with a compression roller, and the moisture content is A fiber D was obtained in the same manner as in Example 2 except that the content was made to be 130%. In the regenerated cellulose fiber before water-repellent processing, the ratio of the H-type carboxyl group to the total amount of carboxyl groups was 20%, and the H-type carboxyl group content was 0.21 mmol / g. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.96 mmol / g. Moreover, it carried out similarly to Example 1 except having used the fiber D, and obtained the nonwoven fabric D which has the fabric weight shown in Table 1, thickness, and a specific volume.

(Example 5)
In place of the aqueous solution of acrylic acid-maleic acid copolymer salt, naphthalene sulfonic acid salt is added to raw material viscose to be 8% by mass with respect to 100% by mass of cellulose, and stirring and mixing are performed by a mixer. Prepared a viscose solution for spinning, and in the spinning step, the spinning speed was 60 m / min, the concentration of sulfuric acid in the spinning bath was 110 g / L, and bleaching with sodium hypochlorite was not performed The fiber E was obtained in the same manner as in Example 2. Moreover, it carried out similarly to Example 1 except having used the fiber E, and obtained the nonwoven fabric E which has the fabric weight shown in Table 1, thickness, and a specific volume. In the regenerated cellulose fiber before water-repellent processing, the ratio of the H-type sulfonic acid group to the total amount of sulfonic acid groups was 80%, and the H-type sulfonic acid group content was 0.68 mmol / g. The total amount of sulfonic acid groups in the obtained water repellent regenerated cellulose fiber was 0.77 mmol / g.

(Example 6)
In place of the aqueous solution of acrylic acid-maleic acid copolymer salt, an anionic acrylic resin aqueous solution viscosity of 2130 mPa · s is added to the raw material viscose so that the anionic acrylic resin becomes 10% by mass with respect to 100% by mass of cellulose The mixture was stirred and mixed in a mixer to prepare a viscose solution for spinning, and in the spinning step, the spinning speed was 60 m / min and the concentration of sulfuric acid in the spinning bath was 110 g / L, except for Example 2 Fiber F was obtained in the same manner. Moreover, it carried out similarly to Example 1 except having used the fiber F, and obtained the nonwoven fabric F which has the fabric weight shown in Table 1, thickness, and a specific volume. In the regenerated cellulose fiber before water-repellent processing, the ratio of the H-type carboxyl group to the total amount of carboxyl groups was 78%, and the H-type carboxyl group content was 0.80 mmol / g. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.93 mmol / g.

(Example 7)
Instead of an aqueous solution of acrylic acid-maleic acid copolymer salt, polyacrylic acid (“Tanomori G-37” manufactured by Arakawa Chemical Industries, Ltd.) is 6% by mass with respect to 100% by mass of cellulose. Thus, it is added to the raw material viscose, stirred and mixed in a mixer, and a viscose solution for spinning is prepared, and the spinning speed is set to 70 m / min in the spinning step in the same manner as in Example 2. , Fiber G (fineness 1.7 dtex) was obtained. Tanomori G-37 is an aqueous dispersion of unneutralized polyacrylic acid, and has a pH of 1.7 to 2.5, a specific gravity of 1.027, and a viscosity of 3,000 to 6,000 mPa at 20 ° C.・ S. In addition, in Tanomori G-37, the concentration of polyacrylic acid (unneutralized product) as the main component was 8.5% by mass. Moreover, it carried out similarly to Example 1 except having used the fiber G, and obtained the nonwoven fabric G which has a fabric weight shown in Table 1, thickness, and a specific volume. In the regenerated cellulose fiber before water-repellent processing, the ratio of the H-type carboxyl group to the total amount of carboxyl groups was 57%, and the H-type carboxyl group content was 0.42 mmol / g. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.67 mmol / g.

(Example 8)
Example 1 except that an aqueous solution of acrylic acid / maleic acid copolymer salt was added to the raw material viscose so that the acrylic acid / maleic acid copolymer salt became 5% by mass with respect to 100% by mass of cellulose. Fiber X was obtained in the same manner. Moreover, it carried out similarly to Example 1 except having used the fiber X, and obtained the nonwoven fabric X which has a fabric weight shown in Table 1, thickness, and a specific volume. In the regenerated cellulose fiber before water-repellent processing, the ratio of the H-type carboxyl group to the total amount of carboxyl groups was 94%, and the H-type carboxyl group content was 0.53 mmol / g. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.51 mmol / g.

(Example 9)
Fiber Y (1.7 dtex) in the same manner as in Example 8, except that in the spinning step, the spinning speed was 50 m / min, and in the water repellent finishing, drying was performed for 10 minutes with a dryer set at 100 ° C. I got The actual temperature at this time was 85 ° C. The total amount of carboxyl groups in the obtained water repellent regenerated cellulose fiber was 0.52 mmol / g. Moreover, except using the fiber Y, it carried out similarly to Example 8, and obtained the nonwoven fabric Y which has a fabric weight shown in Table 1, thickness, and a specific volume.

(Comparative example 1)
To replace the aqueous solution of acrylic acid-maleic acid copolymer salt with titanium dioxide (“TITONE” manufactured by Sakai Chemical Industry Co., Ltd.) as raw material viscose so that it becomes 0.5 mass% with respect to 100 mass% of cellulose The mixture was stirred and mixed in a mixer to prepare a viscose solution for spinning, and in the spinning step, the spinning speed was 60 m / min and the sulfuric acid concentration in the spinning bath was 110 g / L, except for the example. Fiber H was obtained in the same manner as 2). Moreover, it carried out similarly to Example 1 except having used the fiber H, and obtained the nonwoven fabric H which has the fabric weight shown in Table 1, thickness, and a specific volume.

(Comparative example 2)
In the water repellent finish, only an acrylic water repellent (“Neoseed NR-158” manufactured by Nikka Chemical Co., Ltd.) is used as the water repellent finish, and the adhesion ratio of water repellent particles to fibers is 1% by mass. A fiber I was obtained in the same manner as in Example 2 except for the above. Moreover, it carried out similarly to Example 1 except having used the fiber I, and obtained the nonwoven fabric I which has the fabric weight shown in Table 1, thickness, and a specific volume.

(Comparative example 3)
A fiber J was obtained in the same manner as in Comparative Example 1 except that after the fibers were squeezed with a compression roller in the scouring step without conducting the water repelling process, the fibers were dried at 100 ° C. for 15 minutes. Moreover, it carried out similarly to Example 1 except having used the fiber J, and obtained the nonwoven fabric J which has a fabric weight shown in Table 1, thickness, and a specific volume.

(Comparative example 4)
A fiber K was obtained in the same manner as in Comparative Example 1 except that the drying process was performed at 170 ° C. for 10 minutes in the water repelling process. Moreover, it carried out similarly to Example 1 except having used the fiber K, and obtained the nonwoven fabric K which has the fabric weight shown in Table 1, thickness, and a specific volume.

(Comparative example 5)
A fiber L was obtained in the same manner as in Example 1 except that the fiber was squeezed with a compression roller in a scouring step without water repelling treatment, and then dried at 100 ° C. for 15 minutes.

  The whiteness and water repellency of fibers A to K, X and Y were measured as follows, and the results are shown in Table 1 below. Also, the basis weight, thickness, water repellency, contact angle (also referred to as water repellent angle) and stiffness of nonwoven fabrics A to K, X and Y were measured as follows, and the results are shown in Table 1 below. The Further, the tensile strength (strength), elongation (stretching degree) and apparent Young's modulus of the fibers A, B, J to L, and Y were measured as follows, and the results are shown in Table 2 below. In the examples, the total amount of carboxyl groups, the amount of H-type carboxyl groups and the amount of salt-type carboxyl groups in the regenerated cellulose fiber before and after the water repelling process were measured as follows. The ammonia deodorizing property of the fiber Y and the pH buffer property of the non-woven fabric Y were evaluated as follows, and the results are shown in Tables 3 and 4 below.

(Whiteness of fiber)
The whiteness of the fiber was measured according to JIS Z 8722 using a "color difference meter CR-410" manufactured by Konica Minolta Co., Ltd. The whiteness was calculated from the following equation using the defined XYZ color system (Yxy color system) Y, x, y.
Whiteness = (1-x-y) × Y / 1.18 × y
In the measurement, 200 g of sample cotton was put in a container dedicated to measurement (black container of 20 cm × 20 cm × 14 cm in height), defibrillated so as to eliminate lumps, and used sample cotton packed so as to have a constant thickness. .

(Fiber repellant)
(1) 1 g of raw cotton was collected and lightly rounded.
(2) 300 mL of water was placed in a 300 mL beaker, and a sample collected from a height of 1 cm from the water surface was gently dropped. The height from the beaker bottom to the water surface was 7 cm.
(3) The condition of the raw cotton was observed for 10 minutes, the time until the raw cotton reached the bottom of the beaker (water immersion time) was measured, and the water repellency was evaluated based on the following three levels.
:: no settling for 10 minutes or more, good water repellency し た: water absorbed but no settling to bottom, water repellant x: settling to bottom within 10 minutes, no water repellency

(Weight, thickness and specific volume of non-woven fabric)
The fabric weight and thickness were measured according to JIS L 1913. The thickness was measured under a load of 0.5 kPa. The specific volume was calculated based on the values of basis weight and thickness.

(Water repellency of non-woven fabric)
One drop (0.049 mL) of water was dropped on the surface of the non-woven fabric, and after 10 seconds, the state of water droplets was observed and evaluated on the basis of the following three steps.
○: The shape of the water droplet does not change from the time of landing, good water repellency △: The shape of the water droplet is wider than when landing, but no water absorption, water repellency is possible ×: water absorption, no water repellency

(Contact angle of non-woven fabric with water)
(1) Ion-exchanged water was placed in a 25 mL burette (manufactured by As One), and set in a burette table.
(2) The distance between the tip of the burette and the non-woven fabric was set to 1 cm.
(3) One drop (0.049 mL) of ion-exchanged water was dropped, and after 10 seconds from water landing, as shown in FIG. 1, the contact angle α of the nonwoven fabric 10 with the water droplet 20 was measured. The measurement was performed at n = 2, and the contact angles of both the left and right drops were measured and averaged.

(Stiffness of nonwoven fabric)
The non-woven fabric is cut so that each has a width and width of 2 cm × 15 cm, and it conforms to the 45 ° cantilever method of JIS L1096, in the vertical direction (machine direction, MD), horizontal direction (method orthogonal to the machine direction, CD ) Was measured. Also, the average value in the vertical direction and the horizontal direction was calculated.

(Measurement of weight average molecular weight)
The weight average molecular weight (Mw) was determined by measurement under the following conditions by GPC (gel permeation chromatography). When calculating the weight average molecular weight, a portion having a molecular weight of 300 or more on the chart obtained by GPC was defined as a polymer.
Column: GF-7 MHQ (manufactured by Showa Denko KK).
Mobile phase: Pure water is added to 34.5 g of disodium hydrogen phosphate 12 hydrate and 46.2 g of sodium dihydrogen phosphate dihydrate (all are special grade for reagents) to make the total amount 5,000 g, and then Aqueous solution filtered through a 0.45 micron membrane filter.
Detector: UV 214 nm (manufactured by Nippon Waters Co., Ltd. 30, model 481).
Pump: L-7110 (manufactured by Hitachi, Ltd.).
Flow rate: 0.5 mL / min.
Temperature: 35 ° C.
Calibration curve: Sodium polyacrylate standard sample (manufactured by Genwa Science Co., Ltd.).

(Tensile strength, elongation, apparent Young's modulus)
It measured according to JIS L 1015.

(Measurement of total amount of carboxyl group)
(1) A sample of 1.2 g was immersed in 50 mL of a 1 mol / L aqueous hydrochloric acid solution (pH 0.1), stirred and allowed to stand for 5 minutes. After that, stirring was performed again to adjust the pH of the aqueous solution to 2.5. As a result, all carboxyl groups in the sample (fiber) are present as H-form. Next, the sample was washed with water, dried at 105 ° C. for 2 hours with a constant temperature air-flow dryer, and was completely dried. By washing the sample, any excess hydrochloric acid adhering to the fibers will be removed.
(2) A beaker was charged with 100 mL of ion exchange water, 0.4 g of sodium chloride, and 20 mL of a 0.1 mol / L aqueous sodium hydroxide solution.
(3) 1 g of the sample prepared in (1) is precisely weighed [W1 (g)], finely cut into a size not to be wound on a stirrer, put in the beaker prepared in (2), and stirred with a stirrer for 15 minutes did. As a result, all carboxyl groups in the sample (fiber) are converted to the salt form. The stirred sample was suction filtered. 60 mL of the filtrate was taken and titrated with 0.1 mol / L aqueous hydrochloric acid solution using phenolphthalein as an indicator, and the titration amount was taken as X1 (mL).
(4) The total amount Y (mmol / g) of carboxyl groups was calculated based on the following formula. Thus, the amount of sodium hydroxide determined by subtracting the amount of residual sodium hydroxide from the total amount of sodium hydroxide corresponds to the total amount of carboxyl groups in the sample (fiber).
Total amount of carboxyl groups Y (mmol / g) = [[(0.1 × 20) − (0.1 × X1)] × (120/60)] / W 1

(Measurement of the amount of H-type carboxyl group and the amount of salt-type carboxyl group)
(1) The sample was washed with water, dried at 105 ° C. for 2 hours with a constant temperature air dryer, and was completely dried.
(2) A beaker was charged with 100 mL of ion exchange water, 0.4 g of sodium chloride, and 20 mL of a 0.1 mol / L aqueous sodium hydroxide solution.
(3) 1 g of the sample was precisely weighed [W2 (g)], finely cut into a size not to be wound on a stirrer, placed in the beaker prepared in (2), and stirred with a stirrer for 15 minutes. The stirred sample was suction filtered. 60 mL of the filtrate was taken and titrated with a 0.1 mol / L aqueous hydrochloric acid solution using phenolphthalein as an indicator, and the titration amount was taken as X 2 (mL).
(4) Amount of H-type carboxyl group Z (mmol / g), amount of salt-type carboxyl group U (mmol / g), ratio of amount of H-type carboxyl group (%) and salt-type carboxyl group based on the following formula The percentage of the amount of (%) was calculated.
Amount of H-type carboxyl group Z (mmol / g) = [{(0.1 × 20) − (0.1 × X2)] × (120/60)] / W 2
Amount of salt type carboxyl group U (mmol / g) = total amount of carboxyl group Y (mmol / g) —amount of H type carboxyl group Z (mmol / g)
Ratio of amount of H-type carboxyl group (%) = {amount of H-type carboxyl group Z (mmol / g)]
/ {Total amount of carboxyl groups Y (mmol / g)] x 100
Ratio of amount of salt type carboxyl group (%) = {amount of salt type carboxyl group U (mmol / g)]
/ {Total amount of carboxyl groups Y (mmol / g)] x 100

(Ammonia deodorant)
Ammonia deodorant evaluation conforms to the instrumental analysis test method (detector tube method) specified by the SEK mark fiber product certification standard (revised on April 1, 2018) of the Japan Society of Fiber Evaluation Technology (JTETC) I did it. Specifically, it was evaluated as follows. 0.30 g of a sample (raw cotton) was placed in a 5 L Tedlar bag and sealed. Next, using a syringe, 3 L of ammonia gas was injected into the Tedlar bag to a prescribed initial concentration. Two hours after the ammonia gas was injected, the concentration of ammonia gas gas in Tedlar bag was measured by a detection tube. A blank test was conducted in the same manner. And the reduction rate of ammonia was calculated | required by the following formula using the measured value in the blank test, and the measured value at the time of using a sample. The initial concentration of ammonia was 100 ppm.
Decreasing rate (%) = [(measured value in blank test after 2 hours-measured value when using sample after 2 hours) / measured value in blank test after 2 hours] × 100

(PH buffering property)
(1) The sample (non-woven fabric) was cut into 1 cm square.
(2) Three 1-cm square samples were stacked, and 0.1 ml of the pH standard solution adjusted to pH 4, 5, 6, 7, 8, 9, and 10 was dropped, respectively, and immersed for 30 to 60 seconds.
(3) The pH of the sample immersed in the pH standard solution was measured with a pH meter ("LAQUAtwin B-712" manufactured by HORIBA). The measurement was performed at n = 4 and the values were averaged.

As seen from the results in Table 1, it contains a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group, and an isocyanate compound and a non-fluorinated water repellent bond to the fiber surface. In the fiber of the example, the whiteness of the fiber was Hw 80 or more, and it had water repellency in any state of raw cotton and non-woven fabric. Contact angle with water of the nonwoven fabric using fibers of Example (specific volume 13.0 cm ³ / g or more 15.0 cm ³ / g or less) is not less than 65 degrees, had a durable water repellent . As can be seen from the results in Table 3, the fibers of the examples had high ammonia deodorizing properties. As can be seen from the results in Table 4, the nonwoven fabrics using the fibers of the examples had high pH buffering properties in the range of pH 4 to 10.

  The fiber of Comparative Example 1 which is subjected to water repellent processing with an isocyanate compound and a non-fluorinated water repellent but does not contain a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group is In the state of raw cotton, it has water repellency, but in the state of non-woven fabric, it has no water repellency and is inferior in the durability of water repellency. The fiber of Comparative Example 2 which contains a carboxyl group-containing compound but has a water-repellent finish with only a non-fluorine-based water repellent also has water repellency in the state of raw cotton, but it has water repellency in the state of nonwoven fabric. It did not have, and it was inferior to the durability of water repellency. The fiber of Comparative Example 3 which does not contain a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group and is not subjected to water repellant processing is water repellant in any state of raw cotton and non-woven fabric. I did not have it. The fiber of Comparative Example 4 in which the heat treatment was carried out at 170 ° C. in the water repellent step was either raw cotton or non-woven fabric although it did not contain a compound containing one or more acidic groups selected from the group consisting of carboxyl groups and sulfonic acid groups. It had water repellency even in the state of 1. However, the whiteness was less than Hw80.

  As seen from the results in Table 2, it contains a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group, and an isocyanate compound and a non-fluorinated water repellent bond to the fiber surface. The fibers of Examples 1 to 2 have a dry-wet strength, a dry-wet elongation, as compared with Comparative Example 5 including a compound containing one or more acidic groups selected from the group consisting of the same carboxyl group and sulfonic acid group. And it was a comparable value in the wet Young's modulus, and cellulose itself did not deteriorate. In particular, Example 2 had a dry Young's modulus higher than that of Comparative Example 5, and was a rigid fiber. In addition, although the dry Young's modulus of Example 1 is lower than that of Comparative Example 5, it is about the same as that of ordinary rayon of Comparative Example 3 and was a practically sufficient value.

  Further, the fiber of Comparative Example 4 in which the heat treatment was carried out at 170 ° C. in the water repellent step is water repellent processed although it does not contain a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group. Since the wet strength and the wet Young's modulus are lowered and the wet-dry Young's modulus ratio (WY / DY) is significantly lowered as compared with Comparative Example 3 in which the above is not performed, the cellulose itself is exposed to high heat. Therefore, it is considered that the amorphous part has deteriorated. On the other hand, WY / DY in the example satisfied 12 or more because deterioration of the cellulose itself was suppressed.

  The water repellent regenerated cellulose fiber of the present invention can be used, for example, in fiber structures such as spun yarn, knitted fabric, woven fabric, non-woven fabric, tow, filament, batting (padding), paper and the like. In addition, the fiber structure of the present invention can be used for sanitary materials such as clothes, cosmetic puffs, face masks, surface sheets, second sheets, absorbers, back sheets and the like.

10 non-woven fabric 20 water drops

Claims (8)

Water-repellent regenerated cellulose fiber having water repellency,
The water repellent regenerated cellulose fiber contains a compound containing at least one acidic group selected from the group consisting of a carboxyl group and a sulfonic acid group, and an isocyanate compound and a non-fluorinated water repellent bond to the fiber surface. Yes,
The water repellent regenerated cellulose fiber has a whiteness of Hw 80 or more. Water-repellent regenerated cellulose fiber having water repellency,
The water repellent regenerated cellulose fiber contains a compound containing at least one acidic group selected from the group consisting of a carboxyl group and a sulfonic acid group, and an isocyanate compound and a non-fluorinated water repellent bond to the fiber surface. Yes,
The water-repellent regenerated cellulose fiber has a wet-dry Young's modulus ratio represented by the following formula (1) with an apparent Young's modulus at standard time to an apparent Young's modulus when wet measured according to JIS L 1015 is 12.0 or more Water-repellent regenerated cellulose fiber characterized in that
Wet dry Young's modulus ratio = (Aspect Young's modulus when wet / Apparent Young's modulus when standard) × 100 (1)   The water repellent regenerated cellulose fiber according to claim 1, wherein the non-fluorine water repellent is a hydrocarbon water repellent.   The water repellent regenerated cellulose fiber according to any one of claims 1 to 3, wherein the compound having a carboxyl group is one or more selected from the group consisting of polyacrylic acid and acrylic acid-maleic acid copolymer.   The water repellent regenerated cellulose fiber according to any one of claims 1 to 4, wherein a contact angle of the water entangled nonwoven fabric made of 100 mass% of the water repellent regenerated cellulose fiber with water is 65 degrees or more. It is a manufacturing method of the water repellent regenerated cellulose fiber according to any one of claims 1 to 5,
A viscose solution containing cellulose is mixed with a compound containing one or more acidic groups selected from the group consisting of a carboxyl group and a sulfonic acid group to prepare a viscose solution for spinning, and the viscose solution for spinning is used as a nozzle More extruded, coagulated and regenerated to make viscose rayon yarn,
The viscose rayon yarn is treated with a treatment liquid for water-repellent finish containing an isocyanate compound and a non-fluorinated water repellent, and then the fiber surface is heat treated to a temperature of 40 ° C. to 110 ° C. A method of producing water-repellent regenerated cellulose fiber.   The method according to claim 6, wherein the isocyanate-based compound is a blocked isocyanate-based crosslinking agent having a blocked isocyanate group.   A fiber structure comprising the water repellent regenerated cellulose fiber according to any one of claims 1 to 7.

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