JP6626948B2 - Hydrophilic cellulose acetate tow band and absorber using the same - Google Patents

Description

  The present invention provides a hydrophilized cellulose acetate tow band useful as an absorbent for absorbent materials for sanitary materials such as diapers and sanitary articles, a fiber sheet formed from the hydrophilized cellulose acetate tow band, and a fiber sheet formed from the hydrophilized cellulose acetate tow band. The present invention relates to an absorber (absorbent article) used.

  Conventionally, absorbents used for sanitary products such as disposable diapers are made of fluff pulp and a polymer absorbent such as SAP (highly water-absorbent resin). Such an absorber is thick and inconvenient to carry. Further, in fluff pulp, there is also a problem that the liquid permeation speed is low because the fiber itself absorbs water.

  In order to solve the above-mentioned problems of the conventional absorbent body using fluff pulp, an absorbent body in which SAP is mainly added to cellulose acetate has been proposed. For example, Patent Literature 1 discloses that a crimped tow is spread in a direction perpendicular to the direction of movement of the tow, dealigned, and shaped into a substantially rectangular cross section, and the entire shaped tow has a superabsorbent high toughness. A method for producing an absorbent composite that distributes particulate matter such as molecules is disclosed. As the tow, a cellulose acetate tow manufactured for a tobacco filter is used. With such an absorbent using cellulose acetate, the thickness of the absorbent can be reduced, and a disposable diaper that is convenient to carry can be manufactured. In addition, there is an advantage that SAP can be used effectively because of excellent transparency. However, a thin absorbent using cellulose acetate has a problem in terms of water absorption properties, particularly liquid diffusion and liquid retention. That is, there is a problem that the absorption of liquid such as urine concentrates in a local area and does not spread around, and there is a problem that the liquid is poorly retained, so that it is easy to leak when tilted. Among the water absorption functions of retention, the liquid diffusibility and liquid retention were slightly inferior, and the balance was poor.

  As a technology of an absorber using a filament other than cellulose acetate, Patent Document 2 discloses an absorbent using a nonwoven fabric mainly composed of a polyolefin-based or polyester-based fiber and having a fiber surface treated with sericin as a skin contact surface side material. A sexual article is disclosed. Also, Patent Document 3 discloses a wet laid web of cellulose fibers for use in producing an air-laid mass of fibers, the fiber treatment comprising cellulose fibers, and at least one agent having a polysaccharide and hydrogen bonding functionality. A wet laid web of fibers, wherein the fiber treatment composition is distributed within the wet laid web of cellulosic fibers. Further, Patent Document 4 discloses a synthetic fiber bundle for transporting an aqueous fluid, in which a fiber is composed of 10% by weight of a solution of poly [polyethylene glycol (1400) terephthalate] and 44.1% by weight of polyethylene glycol (400). Synthetic fiber coated with a lubricant consisting of monolaurate, 44.1% by weight of polyethylene glycol (600) monolaurate and 1.8% by weight of 4-cetyl-, 4-ethylmorpholinium ethosulfate A bundle is disclosed.

  Patent Literature 5 discloses an absorbent article having fibers satisfying specific parameters. This reference describes 49% polyethylene glycol (PEG) 600 monolaurate, polyoxyethylene (13.64) monolaurate, 49% as particularly preferred hydrophilic lubricants that can be used to lubricate fibers. Lubricants consisting of polyethylene glycol (PEG) 400 monolaurate, polyoxyethylene (9.09) monolaurate, and 2% 4-cetyl-4-ethylmorpholinium ethosulfate are described. Further, in this document, polyester is cited as a preferable material to be used in producing fibers, and polyamide, polypropylene, polyethylene, and cellulose ester are exemplified as other materials.

  In the field of cellulose acetate for tobacco filters (filter tow for tobacco), as described in Patent Document 6, in the fiber production process (spinning process), the bunching, smoothness, and antistatic properties of the fiber yarn are used. In order to improve the properties and the like, it is common practice to apply a fiber oil agent to running fiber yarns (filaments). The fiber oil agent contains an oil component as a main component, to which additives such as a surfactant are added as necessary. In the fiber oil agent application technique in such a spinning process, uniformly applying the fiber oil agent improves the bunching property, smoothness, antistatic property, etc. of the fiber yarn, and is caused by contact abrasion with equipment. It is important to prevent quality deterioration due to fiber damage, work environment deterioration due to cut fiber pieces due to wear, and quality deterioration due to cut fiber pieces due to wear. In a tobacco filter tow, it is necessary to crimp the tow in order to ensure airflow resistance, and in order to crimp, it is essential that the tow contains a certain amount of moisture. For this reason, in spinning of a filter tow, a fiber oil emulsion, which is a suspension obtained by diluting a fiber oil with water (that is, a suspension of water and oil), is used. The oil agent concentration in the fiber oil agent emulsion is about 2 to 10% by weight.

JP-A-2004-244794 JP-A-9-322911 JP-A-2004-143653 JP 2001-500198 A JP-A-2003-33398 JP 2007-77525 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cellulose acetate-based absorbent material which can be reduced in thickness, and has all properties of liquid permeability, liquid diffusivity and liquid retention at a high level in a well-balanced manner, and a fiber comprising the cellulose acetate-based absorbent material. An object of the present invention is to provide a sheet and an absorbent body using the fiber sheet.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, formed from cellulose acetate having a specific degree of substitution and having a total denier in a specific range, a surface of a crimped cellulose acetate tow band having an HLB value of It has been found that a material to which a hydrophilizing component having a specific value or more is attached can be used as an absorbent material that can be reduced in thickness and has all properties of liquid permeability, liquid diffusion and liquid retention at a high level in a well-balanced manner. Thus, the present invention has been completed.

  That is, the present invention relates to a crimped cellulose acetate tow band surface formed from cellulose acetate having a degree of substitution of 2.0 to 2.6, and having a total denier of 10,000 to 40,000 and a crimp number of 30 to 60 / inch. The present invention further provides a hydrophilicized cellulose acetate tow band, wherein a hydrophilizing component having an HLB value of 16 or more is impregnated in the cellulose acetate tow band at 0.2 to 2% by weight.

  Further, the present invention provides the cellulose acetate tow band wherein the hydrophilic component having an HLB value of 16 or more is at least one selected from polyoxyethylene sorbitan monolaurate and polyethylene glycol monostearate. provide.

  Further, in the present invention, in addition to the hydrophilizing component having an HLB value of 16 or more, a fiber oil agent is added to the surface of the crimped cellulose acetate tow band at 0.2 to 2% by weight based on the cellulose acetate tow band. A hydrophilic cellulose acetate tow band.

  The present invention also provides the cellulose acetate tow band wherein the total amount of the hydrophilic component having an HLB value of 16 or more and the fiber oil agent is 0.4 to 3% by weight based on the cellulose acetate tow band. I will provide a.

  In addition, the present invention provides the hydrophilic cellulose acetate tow band, wherein the crimped cellulose acetate tow band has a filament denier of 1.0 to 7.0.

  The present invention also provides a fiber sheet formed from the hydrophilized cellulose acetate tow band.

  The present invention further provides an absorber characterized in that a superabsorbent resin is dispersedly arranged in the fiber sheet.

The present invention still further provides (A) a step of discharging cellulose acetate having a substitution degree of 2.0 to 2.6 dissolved in an organic solvent from a spinneret through a spinneret to obtain a cellulose acetate filament;
(B) a step of impregnating the obtained cellulose acetate filament with a fiber oil agent,
(C) a step of attaching a hydrophilizing component to the obtained cellulose acetate filament,
(D) combining cellulose acetate filaments obtained from a plurality of spinning cylinders to obtain a cellulose acetate tow band having a total denier of 10,000 to 40,000; and (E) crimping the cellulose acetate tow band, Provided is a method for producing a hydrophilized cellulose acetate tow band, comprising a step of obtaining a crimped cellulose acetate tow band having a number of crimps of 30 to 60 / inch.

  Further, the present invention provides a cellulose acetate filament obtained by adhering a hydrophilizing component together with a fiber oil agent to the obtained cellulose acetate filament in the step (B), and thereafter, in the step (C), adhering the fiber oil agent and the hydrophilizing component. The present invention provides a method for producing the above-mentioned hydrophilic cellulose acetate tow band, wherein a hydrophilic component is further attached to the filament.

  The present invention also provides a method for producing the hydrophilic cellulose acetate tow band, wherein each step is performed in the order of step (B), step (D), and step (C).

The hydrophilized cellulose acetate tow band of the present invention is formed from cellulose acetate having a substitution degree of 2.0 to 2.6, and has a total denier of 10,000 to 40,000 and a crimp number of 30 to 60 crimps / inch. Since a specific amount of a hydrophilizing component having an HLB value of 16 or more has been impregnated on the surface of the cellulose acetate tow band, the liquid absorption property, particularly the liquid diffusivity and the liquid permeability, while maintaining the liquid permeability characteristic of cellulose acetate tow. The liquid holding property (wetting property) is improved, and the above properties are provided in a well-balanced manner. In addition, since cellulose acetate tow is used, the thickness can be reduced without being bulky. Therefore, it can be used as an absorbent for absorbent materials for sanitary materials such as diapers and sanitary products.
Note that cellulose acetate having a degree of substitution of 2.0 to 2.6 is not water-soluble, and thus its surface is not water-soluble. However, the hydrophilizing component having an HLB of 16 or more is water-soluble. Therefore, the surface of the cellulose acetate can be made hydrophilic by attaching a hydrophilic component having an HLB of 16 or more.
Further, in the absorbent body of the present invention, since the superabsorbent resin (SAP) is dispersed and arranged in the fiber sheet made of the above-mentioned hydrophilic cellulose acetate tow, the liquid permeability inherent to the cellulose acetate tow is maintained. The water absorption time is short, and for example, urinated urine can be absorbed in a short time. In addition, since SAP having excellent liquid diffusibility and a wide surface of SAP can be used, for example, there is little recurrence (rewetting) of urine, and a comfortable feeling in use can be obtained. Furthermore, the liquid retention property is excellent, and the lateral leakage due to the movement of a baby or the like can be reduced.

  Furthermore, according to the method for producing a hydrophilicized cellulose acetate tow of the present invention, it is possible to industrially efficiently produce a cellulose acetate tow whose surface is excellent in both properties of liquid permeability and water absorption properties and is hydrophilic. it can.

It is explanatory drawing which shows typically an example of the apparatus used for the manufacturing method of the hydrophilized cellulose acetate tow band of this invention.

[Hydrophilic cellulose acetate tow band]
The hydrophilized cellulose acetate tow band of the present invention is formed from cellulose acetate having a substitution degree of 2.0 to 2.6, and has a total denier of 10,000 to 40,000 and a crimp number of 30 to 60 crimps / inch. A hydrophilic component having an HLB value of 16 or more is adhered to the surface of the cellulose acetate tow band. In the present invention, in the final form, the cellulose acetate tow band may be crimped and a hydrophilic component having an HLB value of 16 or more may be attached, and the operation order of the crimping and the attachment of the hydrophilic component is not limited. Absent.

  In the present invention, the degree of substitution (acetyl substitution degree) of the cellulose acetate constituting the cellulose acetate tow band is from 2.0 to 2.6, preferably from 2.1 to 2.5.

  The cellulose acetate fibers constituting the cellulose acetate tow band are usually long fibers produced by dry spinning. Depending on the shape of the die and other spinning conditions, different cross-sectional shapes and fineness can be obtained.

  The cross-sectional shape of the cellulose acetate fiber may be circular or irregular (for example, elliptical, polygonal, T-shaped, I-shaped, Y-shaped, X-shaped, etc.). . Fibers having irregular cross-sections have greater water-absorbing capacity than fibers having circular cross-sections, and are more suitable for use as absorbent materials. The cross-sectional shape of the cellulose acetate fiber is particularly preferably a Y-shape (Y-shape).

  The single fiber fineness of the cellulose acetate fiber is not particularly limited, and is, for example, 0.1 to 20 denier, preferably 1.0 to 7.0 denier.

  As described above, the cellulose acetate tow band in the present invention is an aggregate of crimped long fiber bundles. The total denier of the cellulose acetate tow band is 10,000 to 40,000, preferably 15,000 to 35,000, and more preferably 20,000 to 30,000. If the total denier of the cellulose acetate tow band is less than 10,000, it becomes difficult to apply crimp uniformly, and it is difficult to maintain the shape of the absorber when the absorber is used. On the other hand, if the total denier of the cellulose acetate tow band exceeds 40,000, the thickness of the absorbent as an absorbent becomes too thick to give a rough feeling, which is not preferable.

  The number of crimps in the crimped cellulose acetate tow band is 30 to 60 pieces / inch, preferably 30 to 40 pieces / inch. When the number of crimps of the cellulose acetate tow band is less than 30 pieces / inch, the swelling becomes insufficient when the fiber is opened. On the other hand, when the number of crimps exceeds 60 pieces / inch, the crimp becomes high and the tow is damaged, which is not preferable.

  In the present invention, as described above, it is important that a hydrophilic component having an HLB value of 16 or more is attached to the surface of the cellulose acetate tow band.

  The hydrophilic component having an HLB value of 16 or more is not particularly limited, and a nonionic surfactant having an HLB value of 16 or more can be preferably used. More specifically, examples of the hydrophilic component having an HLB value of 16 or more include, for example, polyoxyethylene sorbitan monolaurate (twin 20) (HLB value of 16.7) and polyethylene glycol monostearate (HLB value of 18.0). And the like, but are not limited thereto. The hydrophilizing component having an HLB value of 16 or more may be used alone or in combination of two or more.

  The HLB value of the hydrophilizing component is preferably 16.5 or more. The upper limit of the HLB value of the hydrophilizing component is not particularly limited, but is usually 20.0, and may be 19.0.

  As the hydrophilizing component having an HLB value of 16 or more, the above polyoxyethylene sorbitan monolaurate (HLB 16.7) is particularly preferable because of its high versatility.

  The amount of the hydrophilic component having an HLB value of 16 or more added to the cellulose acetate tow band is 0.2 to 2% by weight, and preferably 0.25 to 1% by weight, based on the cellulose acetate tow band. Since the hydrophilic component having an HLB value of 16 or more is attached to the cellulose acetate tow band in the above range, the liquid diffusion property and the liquid retention property (wetting) while maintaining the liquid permeability inherent in the cellulose acetate tow band are maintained. Characteristics) are greatly improved.

  The method for treating the surface of the cellulose acetate tow band with a hydrophilic component having an HLB value of 16 or more is not particularly limited. For example, using an aqueous solution in which a hydrophilizing component having an HLB value of 16 or more is dissolved in water, and applying a hydrophilic treatment having an HLB value of 16 or more to the cellulose acetate tow band surface by a general surface treatment method such as an immersion method, a spraying method, or a coating method. Component can be added (attached).

  In the present invention, the above-mentioned specific amount of the hydrophilic component having an HLB value of 16 or more may be added to the surface of the cellulose acetate tow band, but the spinnability, the bunching of the fiber yarn, the smoothness of the fiber surface, and the antistatic property In order to improve the anti-friction property, the surface of the cellulose acetate tow band is preferably further treated with a fiber oil agent.

  The fiber oil agent is not particularly limited, and a known or commonly used fiber oil agent can be used. Examples of the fiber oil agent include mineral oil and esterified oil. Among them, mineral oil is preferred. The fiber oil agent may be used alone or in combination of two or more.

  The amount of the fiber oil agent added to the cellulose acetate tow band can be appropriately selected depending on the type of the cellulose acetate tow band or the fiber oil agent, the treatment method, and the like. Generally, for example, 0.2 to 2% by weight based on the cellulose acetate tow band , Preferably 0.25 to 1% by weight.

  The method for treating the surface of the cellulose acetate tow band with a fiber oil agent is not particularly limited. For example, using a fiber oil itself, a solution in which the fiber oil is dissolved in an organic solvent, or an emulsion in which the fiber oil is suspended in water, immersion method, spraying method, cellulose acetate by a general surface treatment method such as a coating method. A fiber oil agent can be applied (attached) to the toe band surface.

  When using an emulsion in which a fiber oil is suspended in water (fiber oil emulsion), a surfactant may be added as necessary. Examples of the surfactant include an anionic surfactant and a nonionic surfactant having an HLB value of less than 16.

  As the fiber oil emulsion, a fiber oil emulsion having a total light transmittance of 30% or more of light at 850 nm measured at an emulsion concentration of 5% by weight is preferable (see JP-A-2007-77525). By attaching such a fiber oil emulsion to the cellulose acetate tow fiber yarn, the quality of the fiber deteriorates due to the damage of the fiber due to contact abrasion with the equipment in the fiber manufacturing process, and the work environment deteriorates due to the fiber pieces cut by the abrasion. And the frictional force between the spinning guide and the tow band during filament spinning is reduced, and the frequency of Gody roll breakage in the spinning process can be significantly reduced.

  When a fiber oil agent is attached to the surface of the cellulose acetate tow band together with the hydrophilic component having an HLB value of 16 or more, the total amount of the hydrophilic agent having an HLB value of 16 or more and the fiber oil agent is, for example, 0.4 to 3% by weight, Preferably it is 0.5 to 2% by weight, more preferably 0.5 to 1.5% by weight, further preferably 0.6 to 1.2% by weight. If the total amount of the hydrophilic component having an HLB value of 16 or more and the fibrous oil agent is too large, problems such as loosening of the yarn and dropping of droplets may occur during the production process.

  The hydrophilized cellulose acetate tow band of the present invention has a specific denier in a specific range, and a number of crimps in a specific range. Is attached, while maintaining the liquid permeability which is the original characteristic of cellulose acetate tow, the water absorption property, especially the liquid diffusion property and the liquid retention property (wetting property) are improved, and the above properties are provided in a well-balanced manner. . Further, since the cellulose acetate tow band is used, the thickness can be reduced without being bulky. Therefore, it can be used as an absorbent for absorbent materials for sanitary materials such as diapers and sanitary products.

  The hydrophilized cellulose acetate tow band of the present invention can be produced, for example, based on the following method.

[Production of Cellulose Acetate Tow Band Hydrophilized]
The cellulose acetate tow band that has been hydrophilized can be produced by treating the surface of the cellulose acetate tow band with a hydrophilizing component (particularly, a hydrophilizing component having an HLB value of 16 or more). The surface of the cellulose acetate tow band is treated with a fiber oil agent in addition to the above-mentioned hydrophilizing component in order to improve spinnability, bundle property of fiber yarn, smoothness of fiber surface, antistatic property and antifriction property. Is preferred.

As a method for producing a cellulose acetate tow band in which both a hydrophilizing component and a fiber oil agent are provided (attached) to the surface of the cellulose acetate tow band, for example,
(A) a step of discharging cellulose acetate having a substitution degree of 2.0 to 2.6 dissolved in an organic solvent from a spinneret through a spinneret to obtain a cellulose acetate filament;
(B) a step of impregnating the obtained cellulose acetate filament with a fiber oil agent,
(C) a step of attaching a hydrophilizing component to the obtained cellulose acetate filament,
(D) combining cellulose acetate filaments obtained from a plurality of spinning cylinders to obtain a cellulose acetate tow band having a total denier of 10,000 to 40,000; and (E) crimping the cellulose acetate tow band, A method of obtaining a hydrolyzed cellulose acetate tow band through a step of obtaining a crimped cellulose acetate tow band having a crimp number of 30 to 60 pieces / inch.

  In the above-mentioned production method, the attachment (application) of the fiber oil [step (B)] and the attachment (application) of the hydrophilic component [step (C)] may be performed simultaneously or sequentially (in this case, Either one may be applied first, but it is preferable to apply the fiber oil agent first), or they may be combined. The step (D) of forming the tow band may be performed before or after the step (B), or may be performed before or after the step (C). In the present invention, each step is preferably performed in the order of step (B), step (D), and step (C).

  The above-described production method includes, for example, three embodiments of the following method I, method II, and method III.

[Method I]
In the step (B), a cellulose oil agent is attached to the cellulose acetate filament obtained in the step (A) (no hydrophilic component is attached), and then in the step (C), the cellulose acetate filament attached with the fiber oil agent Method of attaching a hydrophilizing component to water.
[Method II]
A method of impregnating the cellulose acetate filament obtained in the step (A) with a hydrophilizing component together with a fiber oil agent in the step (B) [a method of simultaneously performing the step (B) and the step (C)].
[Method III]
In the step (B), a hydrophilic component is attached to the cellulose acetate filament obtained in the step (A) together with the fiber oil, and then in the step (C), the cellulose acetate filament is attached with the hydrophilic component together with the fiber oil. To further add a hydrophilic component.

  Among these methods, the method III is characterized in that the hydrophilizing component is easily present on the outermost surface, and the water absorbing property, in particular, the liquid diffusing property and the liquid retaining property (wetting property) can be greatly improved. Since the hydrophilizing component is applied after the mixture is applied, this is a particularly preferable method in that the hydrophilizing component to be applied later is easily applied. In the case of the method III, the amount of the hydrophilizing component used in the step (C) is, for example, 5 to 95 times the total amount of the hydrophilizing component used [total amount used in the steps (B) and (C)]. %, Preferably 30 to 90% by weight, more preferably 50 to 85% by weight.

  In any of the above methods, in the step (B), a fibrous oil agent (or a mixture of a fibrous oil agent and a hydrophilizing component) is applied in the form of a cellulose acetate tow fiber yarn obtained by collecting and bundling a large number of cellulose acetate filaments. Is preferred.

  Further, in the step (C), a hydrophilic component is added to a tow band obtained by combining cellulose acetate filaments (particularly, cellulose acetate tow fiber yarns) obtained from a plurality of spinning cylinders [that is, after the step (D)]. The attachment is preferred from the viewpoint of production efficiency and the like.

  FIG. 1 is an explanatory view schematically showing one example of an apparatus used in the method for producing a hydrophilized cellulose acetate tow band of the present invention.

  In the apparatus of FIG. 1, a plurality of cellulose acetate filaments spun from a spinneret 1 are bundled in a plurality of spinning cylinders to form a rope-like cellulose acetate tow fiber yarn 2, which is obtained from the plurality of spinning cylinders. The cellulose acetate tow band 7 is manufactured by bundling the cellulose acetate tow fiber yarns 2 into a plurality of strips.

  This device comprises a fiber oil application device 3 for applying a fiber oil agent (or a mixture of a fiber oil agent and a hydrophilizing component) to the cellulose acetate tow fiber yarn 2, and a fiber oil agent (or fiber oil agent) obtained from a plurality of spinning cylinders. Tow band forming means 6 for forming a cellulose acetate tow band 7 by bundling the cellulose acetate tow fiber yarns 2 provided with the mixture of the hydrophilizing components), and a cellulose acetate tow band 7 formed by the tow band forming means 6 Component imparting device 8 for imparting a hydrophilic component (particularly, a hydrophilic component having an HLB value of 16 or more) to the cellulose acetate tow band 7 having the hydrophilic component imparted thereto. And Further, this apparatus is provided with a goded roll (gody roll) 4 and a guide 5 so that the cellulose acetate tow band 7 is smoothly formed from the cellulose acetate tow fiber yarn 2 to which the fiber oil agent has been applied. The method II does not require the hydrophilizing component imparting device 8.

  The fiber oil agent application device 3 is not particularly limited as long as the fiber oil agent (or a mixture of the fiber oil agent and the hydrophilizing component) can be applied to the cellulose acetate tow fiber yarn 2. An apparatus (a fiber oil impregnating apparatus) can be used. Examples of the fiber oil application device 3 include a roller type, a nozzle type, and a slit type.

  The hydrophilic component imparting device 8 is not particularly limited as long as it can impart a hydrophilic component (particularly, a hydrophilic component having an HLB value of 16 or more) to the cellulose acetate tow fiber yarn 2. The oil applying device (fiber oil applying device) can be diverted. That is, by using a hydrophilizing component in place of the fibrous oil (or a mixture of the fibrous oil and the hydrophilizing component) in the fibrous oil applying device (fibrous oil applying device), the device can be used as the hydrophilizing component applying means 8.

  In this example, the application (attachment) of the hydrophilizing component to the surface of the cellulose acetate tow band is performed after the application (attachment) step of the fiber oil agent and the tow band forming step and before the crimping step. The present invention is not limited to this, and may be performed at an appropriate stage. However, since it is desirable to impart spinnability to cellulose acetate tow, bunching of fiber yarns, smoothness of fiber surface, antistatic property and antifriction property at an early stage, the hydrophilic component of cellulose acetate tow is used. The application (attachment) is preferably performed after the application (impregnation) of the fiber oil [particularly after the cellulose acetate tow to which the fiber oil is applied is converted into a tow band]. Further, from the viewpoint that the hydrophilic component can be uniformly attached to the surface of the cellulose acetate tow band, it is preferable that the hydrophilic component is applied (attached) to the surface of the cellulose acetate tow band before the crimping step.

  The crimping device 9 is not particularly limited, and a known or commonly used crimping device can be used. A sufficient crimp (crimper treatment) can be applied to the cellulose acetate tow band 7 by the crimp applying device 9.

[Fiber sheet]
The fiber sheet of the present invention is formed from the hydrophilic cellulose acetate tow band of the present invention.

  The fibrous sheet can be produced, for example, by opening the crimped cellulose acetate tow band and then forming it into a sheet.

  The opening of the crimped cellulose acetate tow band can be performed by using a known or common opening method, for example, a mechanical opening method using a roller or the like, or a gas opening method using air or the like. In addition, opening (blooming) means loosening a fiber by pushing and expanding a crimped fiber in a length direction or a width direction to increase the bulk.

  The method for forming the spread fiber into a sheet shape is not particularly limited, and is a known or conventional method, for example, a method in which the spread fiber is sandwiched between two plate-like bodies and pressed into a sheet shape, and between a pair of rollers. A method of forming a sheet through the opened fibers can be employed.

  Spreading the crimped fiber by pressurized gas and forming the spread fiber obtained by spreading into a sheet shape include, for example, supplying the crimped fiber to an opening chamber having an elliptical cross section or a circular cross section. And a method in which the fiber is opened with a pressurized gas and the obtained fiber is formed into a sheet (see JP-A-2008-255529). According to such a method, it is possible to obtain a fiber sheet which is extremely excellent in absorbability for liquids such as moisture. Further, the thickness and width of the fiber sheet can be easily adjusted, and the thickness can be partially increased. In particular, a fiber sheet having a different thickness distribution in the width direction can be obtained.

The bulk specific gravity of the fiber sheet of the present invention can be appropriately set according to the use and purpose, but is generally 0.005 to 0.1 g / cm ³ , preferably 0.01 to 0.05 g / cm ³ . Further, the fiber sheet of the present invention can be used after being cut into an appropriate size according to the use or purpose.

[Absorber]
In the absorbent body of the present invention, a superabsorbent resin (SAP) is dispersed in the fiber sheet of the present invention. Known materials can be used as the superabsorbent resin (SAP).

The absorber can be produced, for example, by uniformly spraying the superabsorbent resin over the entire fiber sheet or a predetermined range, and hot-pressing. The amount of the superabsorbent polymer is application, can be appropriately set according to the purpose, usually as a basis weight, for example 50 to 1000 g / m ^2, preferably 100 to 500 g / m ^2.

  Since the absorbent of the present invention uses the cellulose acetate tow that has been hydrophilized as an absorbent, the water absorption time is shorter than that of fluff pulp, and it is possible to absorb urinated urine in a short time. it can. In addition, since it is excellent in liquid diffusibility and can use a wide surface of the superabsorbent resin (SAP), there is little recurrence (rewet) of urine or the like, and a comfortable feeling in use can be obtained. Furthermore, the liquid retention property is excellent, and the lateral leakage due to the movement of a baby or the like can be reduced. Therefore, the absorbent of the present invention is particularly useful as an absorbent for sanitary materials such as disposable diapers, sanitary napkins, and breast milk pads.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Preparation Example 1)
A fiber oil agent (mineral oil, trade name “DC-18”, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was adjusted to 35 ° C., and water (diluted water) adjusted to 35 ° C. was added thereto, followed by stirring. A weight percent fiber oil emulsion was prepared.
The phase change point of the fiber oil was 50% by weight, and the dilution rate at the phase change point was 0.13 kg / min per 1 kg of the fiber oil. The average particle size of the emulsion was 0.199 μm. In addition, the total light transmittance of light at 850 nm measured at an emulsion concentration of 5% by weight of the obtained fiber oil emulsion was 34.8%.

(Preparation Example 2)
A hydrophilizing component (polyoxyethylene sorbitan monolaurate, HLB value 16.7, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was dissolved in water to prepare a 8.5% by weight aqueous solution of a hydrophilizing agent.

(Preparation Example 3)
To 30 parts by weight of the fiber oil emulsion obtained in Preparation Example 1, 100 parts by weight of the aqueous solution of the hydrophilizing agent obtained in Preparation Example 2 was added and mixed to prepare a fiber oil agent-hydrophilizing agent mixed solution.

(Example 1)
A hydrophilic cellulose acetate tow band was produced using the apparatus shown in FIG.
Cellulose acetate having a substitution degree of 2.5 (L-50 manufactured by Daicel Corporation) is dissolved in acetone, discharged from a spinneret in a spinning cylinder, and the acetone solvent is volatilized to obtain a cellulose acetate filament. Cellulose acetate filaments were bundled in a rope shape to obtain a cellulose acetate tow fiber yarn.
Next, the obtained cellulose acetate tow fiber yarn was treated with the fiber oil agent emulsion prepared in Preparation Example 1 using a roller type attachment device, and the fiber oil agent was applied (attached) to the fiber surface of the cellulose acetate tow. . The amount of the fiber oil agent impregnated was 0.5% by weight based on the weight of the cellulose acetate tow.
Next, a filament (cellulose acetate tow fiber yarn) is guided through a goded roll, and a plurality of filaments (cellulose acetate tow fiber yarn) from a plurality of spinning tubes are bundled to form a cellulose acetate tow band (cellulose acetate tow band). Tow band). The total denier of this tow band was 24,000. The filament denier was 3.3 (filament cross-sectional shape: Y-shape).
The tow band was treated with the aqueous solution of the hydrophilizing agent prepared in Preparation Example 2 using a roller-type impregnating apparatus, and a hydrophilizing component was applied (attached) to the fiber surface of the cellulose acetate tow. The amount of the hydrophilic component attached was 0.7% by weight based on the weight of the cellulose acetate tow.
Thereafter, the tow band provided with the hydrophilic component is subjected to crimping (crimper treatment) (the number of crimps: 36 pieces / inch), dried, and packed in a bale, and a bale (packing) made of a hydrophilicized cellulose acetate tow band is formed. Body).
The obtained cellulose acetate tow band was hydrolyzed using the method (gas opening method) described in JP-A-2008-255529, and the cellulose acetate tow after opening was 2 g per 10 cm in width and 30 cm in length. The fiber sheet (thickness: 1 cm) made of a cellulose acetate tow band hydrophilized by opening under the following conditions was obtained.
A superabsorbent resin (trade name “Mooney Pants Type L”, collected from Unicharm Co.) was sprayed on the obtained fiber sheet at a basis weight of 250 g / m ² and wrapped with tissue paper to produce an absorber. .

(Example 2)
Same as Example 1 except that the amount of the fiber oil agent was 0.4% by weight based on the cellulose acetate tow and the amount of the hydrophilic component was 0.3% by weight based on the cellulose acetate tow. Was performed to produce an absorber.

(Example 3)
A hydrophilic cellulose acetate tow band was produced using the apparatus shown in FIG.
Cellulose acetate having a substitution degree of 2.5 (L-50 manufactured by Daicel Corporation) is dissolved in acetone, discharged from a spinneret in a spinning cylinder, and the acetone solvent is volatilized to obtain a cellulose acetate filament. Cellulose acetate filaments were bundled in a rope shape to obtain a cellulose acetate tow fiber yarn.
Next, the obtained cellulose acetate tow fiber yarn was treated with the fiber oil agent-hydrophilizing agent mixed solution prepared in Preparation Example 3 using a roller type attachment device, and the fiber oil agent and A hydrophilic component was provided (attached). The amount of the fiber oil agent impregnated was 0.5% by weight based on the weight of the cellulose acetate tow. The amount of the hydrophilic component was 0.4% by weight based on the weight of the cellulose acetate tow.
Next, a filament (cellulose acetate tow fiber yarn) is guided via a goded roll, and a plurality of filaments (cellulose acetate tow fiber yarn) from a plurality of spinning cylinders are bundled to form a cellulose acetate tow band (cellulose acetate tow band). Tow band). The total denier of this tow band was 24,000. The filament denier was 3.3 (filament cross-sectional shape: Y-shape).
Next, the tow band is subjected to crimping (crimper treatment) (the number of crimps: 36 pieces / inch), dried, and packed in a bale to produce a bale (packing body) made of a hydrophilized cellulose acetate tow band. did.
The obtained cellulose acetate tow band was hydrolyzed using the method (gas opening method) described in JP-A-2008-255529, and the cellulose acetate tow after opening was 2 g per 10 cm in width and 30 cm in length. The fiber sheet (thickness: 1 cm) made of a cellulose acetate tow band hydrophilized by opening under the following conditions was obtained.
A superabsorbent resin (trade name “Mooney Pants Type L”, collected from Unicharm Co.) was sprayed on the obtained fiber sheet at a basis weight of 250 g / m ² and wrapped with tissue paper to produce an absorber. .

(Example 4)
A hydrophilic cellulose acetate tow band was produced using the apparatus shown in FIG.
Cellulose acetate having a substitution degree of 2.5 (L-50 manufactured by Daicel Corporation) is dissolved in acetone, discharged from a spinneret in a spinning cylinder, and the acetone solvent is volatilized to obtain a cellulose acetate filament. Cellulose acetate filaments were bundled in a rope shape to obtain a cellulose acetate tow fiber yarn.
Next, the obtained cellulose acetate tow fiber yarn was treated with the fiber oil agent-hydrophilizing agent mixed solution prepared in Preparation Example 3 using a roller type attachment device, and the fiber oil agent and A hydrophilic component was provided (attached). The amount of the fiber oil agent impregnated was 0.6% by weight based on the weight of the cellulose acetate tow. At this stage, the amount of the hydrophilic component attached was 0.4% by weight based on the weight of the cellulose acetate tow.
Next, a filament (cellulose acetate tow fiber yarn) is guided via a goded roll, and a plurality of filaments (cellulose acetate tow fiber yarn) from a plurality of spinning cylinders are bundled to form a cellulose acetate tow band (cellulose acetate tow band). Tow band). The total denier of this tow band was 24,000.
The tow band was treated with the aqueous solution of the hydrophilizing agent prepared in Preparation Example 2 using a roller-type adhering device, and a hydrophilic component was further added (attached) to the fiber surface of the cellulose acetate tow (attachment amount: cellulose acetate). 0.4% by weight based on tow). The total amount of the hydrophilic component was 0.8% by weight based on the weight of the cellulose acetate tow.
Thereafter, the tow band provided with the hydrophilic component is subjected to crimping (crimper treatment) (the number of crimps: 36 pieces / inch), dried, and packed in a bale, and a bale (packing) made of a hydrophilicized cellulose acetate tow band. Body).
The obtained cellulose acetate tow band was hydrolyzed using the method (gas opening method) described in JP-A-2008-255529, and the cellulose acetate tow after opening was 2 g per 10 cm in width and 30 cm in length. The fiber sheet (thickness: 1 cm) made of a cellulose acetate tow band hydrophilized by opening under the following conditions was obtained.
A superabsorbent resin (trade name “Mooney Pants Type L”, collected from Unicharm Co.) was sprayed on the obtained fiber sheet at a basis weight of 250 g / m ² and wrapped with tissue paper to produce an absorber. .

(Comparative Example 1)
An absorbent was manufactured by performing the same operation as in Example 1 except that the amount of the fiber oil agent was 0.9% by weight based on cellulose acetate tow and the treatment with the hydrophilizing component was not performed.

(Comparative Example 2)
The same operation as in Example 1 was carried out except that glycerin (HLB value: 11.1) was used as the hydrophilic component and the amount of the hydrophilic component was 0.4% by weight based on cellulose acetate tow. And an absorber. Incidentally, the amount of the fibrous oil agent to be impregnated was 0.5% by weight based on the cellulose acetate tow as in Example 1.

(Comparative Example 3)
The same as Example 1 except that sorbitan monolaurate (HLB value: 8.6) was used as the hydrophilic component and the amount of the hydrophilic component was 0.5% by weight based on the weight of the cellulose acetate tow. The operation was performed to produce an absorber. Incidentally, the amount of the fibrous oil agent to be impregnated was 0.5% by weight based on the cellulose acetate tow as in Example 1.

(Comparative Example 4)
The same as Example 1 except that polyoxyethylene lanolin (HLB value 13.0) was used as the hydrophilizing component, and the amount of the hydrophilizing component added was 0.5% by weight based on cellulose acetate tow. The operation was performed to produce an absorber. Incidentally, the amount of the fibrous oil agent to be impregnated was 0.5% by weight based on the cellulose acetate tow as in Example 1.

(Comparative Example 5)
In the same manner as in Example 1, a cellulose acetate tow band (tow band) (amount of fiber oil added: 0.5% by weight based on cellulose acetate tow) was produced. The total denier of this tow band was 24,000. The filament denier was 3.3 (filament cross-sectional shape: Y-shape).
The tow band was crimped (crimper treatment) (the number of crimps: 36 pieces / inch) and dried. The obtained tow band is introduced into a roll set according to the method shown in FIG. 1 of JP-A-7-504233, and passed through a stretching bath at 60 ° C. using a stretching ratio of about 1.2: 1. The crimp was released. After producing the tow band made of the non-crimped fiber in this manner, the tow band is treated with the aqueous solution of the hydrophilizing agent prepared in Preparation Example 2 using a roller-type attachment device, so that the fiber surface of the cellulose acetate tow becomes hydrophilic. A chemical component was applied (impregnated). The amount of the hydrophilic component attached was 0.7% by weight based on the weight of the cellulose acetate tow.
Thereafter, the tow band provided with the hydrophilizing component was cut into a length of 2 inches to produce short-fiber hydrophilized cellulose acetate filaments.
The obtained short fiber hydrophilized cellulose acetate filaments are laminated under a condition of 7.5 g per 10 cm in width and 30 cm in length, and a fiber sheet (1 cm in thickness) composed of hydrophilized cellulose acetate filaments is formed. Obtained.
A superabsorbent resin (trade name “Mooney Pants Type L”, collected from Unicharm Co.) was sprayed on the obtained fiber sheet at a basis weight of 250 g / m ² and wrapped with tissue paper to produce an absorber. .

(Comparative Example 6)
In the same manner as in Example 1, a cellulose acetate tow band (tow band) (amount of fiber oil added: 0.5% by weight based on cellulose acetate tow) was produced. The total denier of this tow band was 24,000. The filament denier was 3.3 (filament cross-sectional shape: Y-shape).
The tow band was treated with the aqueous solution of the hydrophilizing agent prepared in Preparation Example 2 using a roller-type impregnating apparatus, and a hydrophilizing component was applied (attached) to the fiber surface of the cellulose acetate tow. The amount of the hydrophilic component attached was 0.7% by weight based on the weight of the cellulose acetate tow.
Thereafter, the tow band provided with the hydrophilic component is subjected to crimping (crimper treatment) (crimping number: 36 pieces / inch), dried, and then cut to a length of 2 inches while applying sufficient tension. Was produced. The number of crimps of this short fiber was 14 pieces / inch.
The obtained short fiber hydrophilized cellulose acetate filaments are laminated under a condition of 7.5 g per 10 cm in width and 30 cm in length, and a fiber sheet (1 cm in thickness) composed of hydrophilized cellulose acetate filaments is formed. Obtained.
A superabsorbent resin (trade name “Mooney Pants Type L”, collected from Unicharm Co.) was sprayed on the obtained fiber sheet at a basis weight of 250 g / m ² and wrapped with tissue paper to produce an absorber. .

(Reference example)
From the top of a fiber sheet (bulk specific gravity 0.025 g / cm ³ , thickness 1 cm) made of pulp staple fiber (kraft pulp), a highly water-absorbent resin (trade name “Moony Pants Type L”, collected from Unicharm Corporation) ) Was sprayed at a basis weight of 250 g / m ² , and wrapped with tissue paper to produce an absorber.

<Evaluation test>
(Measurement of adhesion amount of hydrophilizing component and fiber oil)
Approximately 6 g of a cellulose acetate tow band provided with a fiber oil agent and a hydrophilizing component [after crimping (however, Comparative Example 5 after crimp release)] was weighed out, dried at 105 ° C. for 1 hour, and then released. Cool and weigh accurately. This was introduced into a Soxhlet extraction device (manufactured by Asahi Seisakusho) to extract a fiber oil agent and a hydrophilizing component. The extraction was carried out by refluxing at 100 ° C. for 2 hours using 150 ml of a mixed solvent of hexane: ethyl acetate = 7: 3 (weight ratio) as an extraction solvent. After the extraction, the solvent was removed by an evaporator, and further dried at 105 ° C. for 1 hour, and the weight of the extract was measured. The weight of the extract was divided by the weight of the cellulose acetate tow subjected to the extraction to determine the total amount of the hydrophilic component and the fiber oil agent (% by weight; based on the cellulose acetate tow).
Next, the extract was dissolved in deuterated dimethyl sulfoxide (DMSO-d6), and ¹ H-NMR analysis was performed. From the signal intensity in the ¹ H-NMR spectrum, each of the fiber oil agent and the hydrophilizing component was attached by a calibration curve method. The amount (% by weight; to cellulose acetate tow) was determined.

(Evaluation of absorption performance)
The absorbers manufactured in Examples, Comparative Examples, and Reference Examples were 10 cm × 30 cm in size (tow 2 g, highly water-absorbent resin 7.5 g) (in Comparative Examples 5 and 6, tow 7.5 g, highly water-absorbent). (7.5 g), which was hot-pressed at 100 ° C. and 3.5 MPa for 1 minute with a hot press, and the thickness was adjusted to 2 mm to obtain an evaluation sample.
A cylinder having an inner diameter of 6 cm was placed at the center of the evaluation sample so that the length direction was orthogonal to the surface of the evaluation sample, and 80 cc of physiological saline was injected into the cylinder. At the same time as the injection, the measurement of the absorption rate was started with a stopwatch, and the time when the physiological saline disappeared from the evaluation sample surface was defined as the water absorption time (80 cc water absorption) (unit: second). It can be said that the shorter the absorption time, the better the absorption speed.
Then, 10 minutes and 20 minutes after the first physiological saline injection, another 80 cc of physiological saline was injected and absorbed by the absorber. After absorption, the length of the longest portion in the vertical direction in the area diffused on the absorber surface is measured by applying a ruler parallel to the absorber surface, and the plane diffusion length (240 cc water absorption) (unit: mm) And It can be said that the longer the plane diffusion length is, the more excellent the liquid diffusion property is.

(Evaluation of water retention when inclined)
The absorbers manufactured in Examples, Comparative Examples, and Reference Examples were cut out to a size of 10 cm × 30 cm to obtain evaluation samples.
The evaluation sample was fixed on the surface of the plate fixed at 45 degrees such that the 10 cm side was the upper side, the lower side, and the 30 cm side was the right side and the left side. From a height of about 10 mm above the upper side of the evaluation sample, 80 cc of physiological saline (0.9% by weight) was dropped toward the upper end of the evaluation sample at a flow rate of 80 cc / min using a funnel. The weight of the physiological saline that leaked from the lower end of the evaluation sample without being absorbed by the evaluation sample was measured, and the water retention when inclined (80 cc water absorption) (unit: cc) was determined. It can be said that the smaller the amount of water that leaks out in the water retention test at the time of inclination, the better the liquid retention.

  Tables 1 and 2 show the above evaluation results. In Tables 1 and 2, "total amount of adhering" means the total amount of the amount of hydrophilizing component adhering and the amount of fiber oil agent adhering.

DESCRIPTION OF SYMBOLS 1 Spinneret 2 Cellulose acetate tow fiber thread 3 Fiber oil agent applicator 4 Goded roll
Reference Signs List 5 Guide 6 Tow band forming means 7 Cellulose acetate tow band 8 Hydrophilizing component imparting device 9 Crimp applying device

Claims (11)

An HLB value of 16 or more is formed on the surface of a crimped cellulose acetate tow band formed of cellulose acetate having a degree of substitution of 2.0 to 2.6 and having a total denier of 10,000 to 40,000 and a crimp number of 30 to 60 / inch. Characterized in that the hydrophilic component is impregnated in an amount of 0.3 to 2% by weight based on the cellulose acetate tow band. The hydrophilized cellulose acetate tow band according to claim 1, wherein the hydrophilizing component having an HLB value of 16 or more is at least one selected from polyoxyethylene sorbitan monolaurate and polyethylene glycol monostearate. 3. The surface of the crimped cellulose acetate tow band, in addition to the hydrophilizing component having an HLB value of 16 or more, a fiber oil agent is impregnated at 0.2 to 2% by weight based on the cellulose acetate tow band. 4. The cellulose acetate tow band hydrophilized according to 1. The hydrophilized cellulose acetate tow band according to claim 3 , wherein the total amount of the hydrophilic component having an HLB value of 16 or more and the fiber oil agent is 0.4 to 3% by weight based on the cellulose acetate tow band. The hydrophilic cellulose acetate tow band according to any one of claims 1 to 4 , wherein the crimped cellulose acetate tow band has a filament denier of 1.0 to 7.0. A fiber sheet formed from the hydrolyzed cellulose acetate tow band according to any one of claims 1 to 5 . A fiber sheet formed from the following hydrophilic cellulose acetate tow band.
Cellulose acetate tow band hydrophilized: crimped cellulose acetate formed from cellulose acetate having a degree of substitution of 2.0 to 2.6, having a total denier of 10,000 to 40,000 and a crimp number of 30 to 60 / inch. A hydrophilic component having an HLB value of 16 or more is impregnated on the surface of the tow band at 0.25 to 2% by weight based on the cellulose acetate tow band. An absorbent body, wherein the superabsorbent resin is dispersedly arranged on the fiber sheet according to claim 6 . (A) a step of discharging cellulose acetate having a substitution degree of 2.0 to 2.6 dissolved in an organic solvent from a spinneret through a spinneret to obtain a cellulose acetate filament;
(B) a step of impregnating the obtained cellulose acetate filament with a fiber oil agent,
(C) a step of attaching a hydrophilizing component to the obtained cellulose acetate filament,
(D) combining cellulose acetate filaments obtained from a plurality of spinning cylinders to obtain a cellulose acetate tow band having a total denier of 10,000 to 40,000; and (E) crimping the cellulose acetate tow band, A method for producing a hydrolyzed cellulose acetate tow band, comprising a step of obtaining a crimped cellulose acetate tow band having a number of crimps of 30 to 60 / inch, wherein the hydrophilizing component is the cellulose acetate tow. A method for producing a hydrophilized cellulose acetate tow band, wherein 0.3 to 2% by weight is impregnated with respect to the band. In step (B), a hydrophilizing component is attached to the obtained cellulose acetate filament together with the fiber oil, and then in step (C), the cellulose acetate filament to which the fiber oil and the hydrophilizing component are attached is further hydrophilized. The method for producing a hydrophilized cellulose acetate tow band according to claim 9, wherein the component is attached. The method for producing a hydrophilized cellulose acetate tow band according to claim 9 or 10 , wherein each step is performed in the order of step (B), step (D), and step (C).

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