JPH07216737A - Water repellent fiber and nonwoven fabric using the same - Google Patents

Abstract

PURPOSE:To obtain fibers simultaneously improved in both water repellency and antistatic properties of the fibers composed of a polyolefin or a polyester to a practically satisfactory extent. CONSTITUTION:This water repellent fiber is obtained by applying a surface modifying material composed of (A) 40-80wt.% potassium salt of stearyl phosphate, (B) 50-10wt.% potassium salt of behenyl phosphate and (C) 50-10wt.% polyethylene wax emulsion in an amount of 0.1-1.0wt.% based on the weight of the fiber thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric which is useful as a surface material for diapers and sanitary napkins, and a water-repellent fiber which is a raw material thereof and which is excellent in processability.

[0002]

2. Description of the Related Art The surface material of absorbent articles such as paper diapers and sanitary napkins is required to have water permeability in the central part of the absorbent article for promptly transmitting the liquid to be absorbed to the absorbent material. The end of the absorbent article is required to be water repellent in order to prevent side leakage of the liquid to be absorbed or the liquid once absorbed. Fibers made of polyolefin or polyester are hydrophobic and have a property of being difficult to be wet with water, and thus are suitable for use in the above-mentioned end portions. However, the performance required for the surface material of the absorbent article has been enhanced, and the material for the end portion is required to have higher water repellency while keeping the weight of the nonwoven fabric as small as possible.

Since fibers made of polyolefin or polyester are hydrophobic, they are very easily charged with static electricity, tend to cause accidents such as winding around a cylinder of a card machine or a guide roll, and have poor workability. In order to improve the processability, an antistatic agent is generally attached, but the fiber to which the antistatic agent is attached loses its original hydrophobicity and becomes hydrophilic and loses its water repellency.

As a method of simultaneously satisfying both hydrophobicity, that is, water repellency and processability, that is, antistatic property, Japanese Patent Publication No.
JP-A 3-24116 describes the use of a surface modifier composed of an alkyl phosphate ester salt having 10 to 30 carbon atoms. However, even with this method, satisfactory results regarding water repellency have not yet been obtained.

[0005]

An object of the present invention is to provide a fiber in which both the water repellency and the antistatic property of a fiber made of polyolefin or polyester are simultaneously improved to a practically satisfactory level.

[0006]

Means for Solving the Problems As a result of intensive research to solve the above problems, the present inventor has reached the invention as described below. That is, "(1) Stearyl phosphate potassium salt (A) 40-
80% by weight, behenyl phosphate potassium salt (B) 50 to
10% by weight and polyethylene wax emulsion (C) 50
A water-repellent fiber made of polyolefin or polyester, characterized in that a surface modifier made up of 10% by weight is attached to the fiber at 0.1% to 1.0% by weight. (2) The water-repellent fiber according to item (1), wherein the single yarn fineness is 1.0 to 6.0 denier. (3) A non-woven fabric comprising 30% by weight or more of the water-repellent fiber according to the above (1) or (2) and 70% by weight or less of other fibers. (4) The non-woven fabric according to item (3), which has a basis weight of 8 to 50 g / m ² . It is.

The fibers made of polyolefin or polyester used in the present invention include polyethylene fibers, polypropylene fibers, polyethylene / polypropylene composite fibers, polypropylene / ethylene vinyl acetate copolymer composite fibers, etc., polyolefin fibers, polyethylene terephthalate fibers, polyethylene terephthalate / This refers to polyester fibers such as polyethylene terephthalate / isophthalate copolymer composite fibers, and further polyester / polyolefin composite fibers such as polyethylene terephthalate / polyethylene composite fibers.

The potassium stearyl phosphate used in the present invention is usually a potassium salt of various mixtures of mono-, di- or triesters. In the present invention, the ratio (weight) of the mono-: di-: tri- is from 30 to 40:50.
Those in the range of 60: 5 to 15 are preferably used. The potassium behenyl phosphate salt used in the present invention is also usually a potassium salt of various mixtures of mono-, di- or triesters. In the present invention, a mono-: di-: tri-ratio (weight) of 30-40: 50-60: 5-15 is preferably used. The polyethylene wax emulsion used in the present invention is obtained by emulsifying polyethylene wax with an anionic emulsifier or a nonionic emulsifier, and preferably has a melting point in the range of 30 to 90 ° C.

The surface modifier used in the present invention is the above-mentioned potassium stearyl phosphate salt (A), potassium behenyl phosphate salt (B) and polyethylene wax emulsion (C).
By weight ratio, A / B / C = 40-80 / 50-10 / 5
It is a mixture in the range of 0 to 10 (total 100% by weight). When (A) is less than 40%, the antistatic property of the fiber becomes insufficient,
Problems easily occur in the card process, and if it exceeds 80%, the water repellency becomes insufficient. When (B) is 10% or less, the water repellency of the fiber is insufficient,
If it exceeds 50%, the water repellency will be improved, but since the solubility is low, it will precipitate in the surface modifier and cause unevenness in the quality of the fiber, which is not preferable. When (C) is 10% or less, the water repellency of the fiber is insufficient,
If it exceeds 50%, the water repellency is improved, but the antistatic property is deteriorated and troubles are likely to occur in the card process.

In the present invention, the above (A), (B) and (C)
0.1 to 1.0 based on the weight of fiber
%, Preferably 0.2-0.8% by weight. If the adhesion amount is less than 0.1%, the antistatic property becomes insufficient,
If it exceeds 1.0%, problems such as easy breakage of the web in the card process and excessive surface modifier contaminating the processing machine occur. As a method of attaching the surface modifier to the fiber, a known method such as an oiling roll method in a spinning step, or a spray method or a dipping method on a web or a non-woven fabric can be used.

The nonwoven fabric of the present invention can be obtained by a known method in which the water-repellent fiber is made into a web having a desired areal weight using a card machine, and the nonwoven fabric is made into a nonwoven fabric by a needle punch method, a suction dryer method or a heat roll method. . When this non-woven fabric is used as the surface material of a paper diaper or a sanitary napkin, the water-repellent fiber preferably has a single yarn fineness of 1.0 to 6.0 denier and a non-woven fabric weight of 8 to 50 g / m ² . More preferably, the basis weight is 10 to 30 g / m ² .
If the single yarn fineness is less than 1.0 denier, it becomes difficult to obtain a uniform web on a card machine, and if it exceeds 6.0 denier, the nonwoven fabric becomes coarse and the desired water repellency cannot be obtained. If it is used as a material, it will be rough and hard to the touch, which is not preferable. If the basis weight is less than 8 g / m ² , the surface material is too thin to obtain sufficient water repellency.
If it exceeds g / m ² , water repellency is preferable, but it is unpractical because it is uncomfortable to touch and costly.

As the above surface material, other fibers can be mixed with the water-repellent fiber of the present invention within a range not impairing the effects of the present invention. Examples of other fibers include polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, rayon, cotton and wool.
The mixing ratio of the other fibers is generally 30% by weight or more of the water repellent fiber of the present invention with respect to the weight of the nonwoven fabric.
If the amount of the water-repellent fiber of the present invention in the nonwoven fabric is less than 30%, the desired water repellency cannot be obtained in many cases.

[0013]

The water-repellent fiber of the present invention is excellent in workability and water repellency. Therefore, when the water-repellent fiber is processed and used as an end portion of a paper diaper or a sanitary napkin, it is possible to effectively prevent lateral leakage of liquid. Various products can be obtained.

[0014]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In each example, the following methods were used for physical property evaluation. Water repellency: A web prepared by passing short fibers of a sample through a card machine to prepare a nonwoven fabric having a weight per unit area shown in Table 1 using a suction dryer. 1 cut from this non-woven fabric
A 5 cm square test piece was subjected to water pressure resistance (m) at a lifting speed of 10 m / min according to the low water pressure method (a) of JIS L 1092.
m) was measured. The better the water repellency, the higher the water pressure resistance,
It must be 40 mm or more. The artificial urine having the following composition was used as the measurement liquid.

Artificial urine composition (content in 1 kg) Urea 20.0 g NaCl 8.0 g MgSO4 · 7H2O 0.8 g CaCl2 · 2H2O 0.3 g H2O 970.9 g Antistatic property: sample short fiber at 20 ° C., total body humidity 65 %, The web was passed through a card machine, and the voltage of static electricity generated on this web was measured. If the voltage is 100 V or less, it can be practically used.

Examples 1 to 5 and Comparative Examples 1 to 7 A sheath / core type composite fiber containing polypropylene as a core component and polyethylene as a sheath component at a composite ratio of 50/50 was spun, and shown in Table 1 by an oiling roll in a drawing process. Various tows to which the surface modifiers having various compositions shown were attached were cut into fiber lengths of 51 mm to obtain sample short fibers. These sample short fibers, or other fibers were mixed with the sample short fibers, passed through a card machine to obtain webs, and heat-treated with a suction dryer at 140 ° C. to obtain nonwoven fabrics having a fabric weight shown in Table 1. For each sample, the electrostatic voltage measured in the card process and the water repellency (= water pressure resistance) of the nonwoven fabric are also shown in Table 1.

[0017]

[Table 1]

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Claims (4)

[Claims] 1. Stearyl phosphate potassium salt (A) 4
0-80% by weight, behenyl phosphate potassium salt (B) 5
0-10% by weight and polyethylene wax emulsion (C)
A water-repellent fiber made of polyolefin or polyester, characterized in that a surface modifier made of 50 to 10% by weight is attached to the fiber in an amount of 0.1 to 1.0% by weight. 2. The water repellent fiber according to claim 1, wherein the single yarn fineness is 1.0 to 6.0 denier. 3. A nonwoven fabric comprising 30% by weight or more of the water-repellent fiber according to claim 1 or 2 and 70% by weight or less of other fibers. 4. The weight per unit area is 8 to 50 g / m ^2.
The non-woven fabric described in.