JPH0436702B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an exterior material for sanitary articles such as sanitary napkins and disposable diapers, and a method for manufacturing the same. This type of exterior material has a smooth surface that feels good to the touch, has appropriate bulk and thickness flexibility (cushionability) even under wet conditions, and has good permeability to body fluids. Low exudation is desirable. Conventionally, exterior materials and methods for manufacturing the same have been proposed and implemented, which are intended to provide such desirable conditions. The exterior material according to this known technique is formed into a nonwoven fabric by integrating at least an upper layer and a lower layer, and the upper layer is made of fine denier hydrophobic fibers or mainly composed of the same, and the lower layer is made of thick denier fibers. Hydrophilic fibers or those mainly composed of hydrophilic fibers and bonded by treatment (welding) with a binder or hot roll, and those in which fine denier hydrophobic fibers are disposed in the upper layer and thick fibers in the lower layer. Some use denier hydrophobic fibers and bind the fibers using a binder or heat treatment. but,
In these known techniques, since the fibers are bonded by a binder or heated roll treatment to form a nonwoven fabric, satisfactory cushioning properties and body fluid permeability cannot be obtained. An object of the present invention is to provide an exterior material and a method for manufacturing the same that can solve the drawbacks of the prior art as described above. The present invention will be explained based on embodiments as follows. As shown in FIG. 1, a treated material 1 used in carrying out the present invention includes an upper layer 2 made of first hydrophobic fibers ^2a of 0.8 to 3 denier and 8 to 20 g/m2;
The lower layer web 3 is composed of second hydrophobic fibers 3a whose fiber surfaces have water absorption properties of 15 to 75 g/ ^m2 , and at least 10% by weight of the second hydrophobic fibers have a denier of 3 to 12 denier. It's layered. The material to be treated 1 is formed into a non-woven fabric by introducing a high-speed water stream onto the material from an orifice arranged to face the upper surface of the support and entangling the material. It is formed. If fibers with a denier of 3 or more are used in the upper layer 2, the surface of the finished exterior material will be uncomfortable to the touch. If less than 10% by weight of fibers of 3 denier or more is used in the lower layer 3, the body fluid permeability of the finished exterior material will be poor, and the overall stiffness of the fibers in the lower layer 3 will be reduced, resulting in an inappropriate bulk. , body fluids tend to ooze out. If the fiber content of the upper layer 2 is 8 g/m ² or less, the finished exterior material will have a poor feel as described above. Upper layer 2
If the fiber content of the lower layer 3 is 20 g/m ² or more and the fiber content of the lower layer 3 is 15 g/m ² or less, the body fluid permeability of the finished exterior material will be poor. If the fibers in the lower layer 3 are 75 g/m ² or more, the fine denier fibers in the upper layer 2 will immerse into the thicker denier fibers in the lower layer 3 in the finished exterior material. The effect of fine denier on the upper layer 2 cannot be obtained. In the present invention, examples of "hydrophobic fibers with water absorption properties on the fiber surface" include polyester fibers, acrylic fibers, etc., and these are known in the textile industry as hydrophobic fibers with sweat and water absorption properties. . In carrying out the present invention, these fibers have a sedimentation rate that meets the standards for sanitary products (Ministry of Health and Welfare Notification 285).
It is preferable that the flocculent pulp sedimentation rate test is within 10 seconds. The support and processing steps are not particularly limited, but
The present inventors have published Japanese Patent Application Publication Nos. 57-39268 and 59-125954.
A preferred example is the method for producing a nonwoven fabric by the water jet fiber entanglement method disclosed in No. In these methods, the material to be treated is subjected to fiber entanglement treatment in a preliminary treatment step, and then fiber entanglement treatment is performed in multiple stages in the full treatment step.Please refer to the explanations of these methods for details, but these methods A brief description of the support in
The support to be subjected to the pretreatment process can be a wide non-porous belt placed between rotating rolls, several non-porous belts placed at predetermined intervals between rotating rolls, or a wide perforated belt (mesh screen). ), and a non-porous support with a narrow support surface is placed in contact with the lower surface of the roll, and the support in the full-scale treatment process is composed of a plurality of non-porous rolls arranged at predetermined intervals. According to this process, even if the material to be treated has a low basis weight, the fibers are entangled in the preliminary treatment process to the extent that the texture of the web is not disturbed during the process of moving through the full-scale treatment process, and this is further carried out in the full-scale treatment process. In the process, the fibers are fully entangled. As shown in FIGS. 2 and 3, the exterior material 11 as a nonwoven fabric obtained by the above-described treatment includes an upper layer 20 mainly composed of the first hydrophobic fibers 2a and a second hydrophobic fiber 2a. A lower layer 30 mainly composed of fibers 3a and in which 10% by weight or more of the second hydrophobic fibers are of 3 to 12 deniers is integrated by intertwining the fibers 2a and 3a, and the upper layer 20 and the lower layer 30 In the intermediate layer 40 where the first hydrophobic fibers 2a and the second hydrophobic fibers 3 are in contact with each other,
It is formed into a nonwoven fabric by mixing with a. In the above, the meaning of "main body" means that the material to be treated 1 is subjected to the fiber entanglement treatment by the high-speed water flow as described above, so the upper layer 20 includes the lower layer 30 as shown in FIGS. 2 and 3. A part of the second hydrophobic fibers 3a and a part of the first hydrophobic fibers 2a are mixed in the lower layer 30, and the first and second hydrophobic fibers 2a and 3a are mixed in the upper and lower layers 2.
This is because there is no clear division between 0 and 30. According to the present invention, it is possible to obtain an exterior material that fully satisfies the above-mentioned desirable conditions, and is particularly excellent in cushioning properties and body fluid permeability. This kind of performance can only be obtained by subjecting the material to be treated having the specific structure described above to fiber entanglement treatment using high-speed water jets. Unlike the conventional technology, simply laminating webs and using a binder or heat welding to bind the fibers is not possible. This cannot be achieved depending on the method of engagement. Incidentally, the treatment by the needle punch method is not suitable for the low basis weight exterior material (nonwoven fabric) targeted by the present invention because the basis weight is too low. Example 1 This example shows the difference in performance depending on the basis weight of the fibers that make up the main layer of the upper layer and the lower layer.
Mixed web (upper layer) of polyester fiber of mm and polypropylene fiber of 1.5d x 51mm, and 6d x 51mm
The text describes a composite web made by laminating a web (lower layer) of polyester fibers (fibers coated with polyethylene glycol, product name 38F SA manufactured by Unitika Co., Ltd.) whose surface has been given water absorption properties. A nonwoven fabric was obtained by processing using the water jet fiber entanglement method. The results are shown in Table 1.

[Table] Example 2 This example shows the difference in performance depending on the mixing ratio of hydrophobic fibers that have been given water absorption properties.
10g/ ^m2 polyester fiber and 1.5d×51mm・10g/
Mixed web (top layer) with m ² polypropylene fibers
A composite web made by laminating a mixed web (lower layer) of 6d x 51 mm of water-absorbing polyester fibers and 6d x 51 mm of normal polyester fibers (lower layer) with a total weight of 20 g/m ² was prepared in the same manner as in Example 1. A product was obtained by processing as follows. The results are shown in Table 2.

[Table] The permeability test was conducted using the following method. Layer the filter paper, tissue paper, and sample nonwoven fabric in this order, and place the sample at 20°C from a height of 1 cm above the nonwoven fabric.
Drop 0.04-0.05g of essential water at a rate of 3 drops per second,
It shows the weight that remains in the nonwoven fabric without passing through it.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of the material to be treated in the method of the present invention, Fig. 2 is a schematic sectional view of the exterior material obtained by the method of the present invention, and Fig. 3 is a diagram similar to Fig. 2, but this is expressed more clearly using diagonal lines. DESCRIPTION OF SYMBOLS 1... Material to be treated, 2... Upper layer, 2a... First hydrophobic fiber, 3... Lower layer, 3a... Second hydrophobic fiber, 20... Upper layer, 11... Exterior material, 30... Lower layer , 40...middle class.

Claims (1)

[Scope of Claims] 1. An upper layer mainly composed of a first hydrophobic fiber of 0.8 to 3 denier and 8 to 20 g/m ² and a ^second hydrophobic layer having water absorbency imparted to the fiber surface of 15 to 75 g/m 2 and a lower layer mainly composed of hydrophobic fibers and in which 10% by weight or more of the second hydrophobic fibers are 3 to 12 deniers are integrated by entangling these fibers, and in the intermediate layer where the upper and lower layers are in contact, the first hydrophobic fiber is 1. An exterior packaging material for sanitary articles, characterized in that it is given a nonwoven fabric form by mixing the hydrophobic fibers and the second hydrophobic fibers. 2. The exterior material for sanitary articles according to claim 1, wherein a part of the second hydrophobic fibers of the lower layer are mixed with the first hydrophobic fibers of the upper layer. 3. The exterior material for sanitary articles according to claim 1, wherein a part of the first hydrophobic fibers of the upper layer are mixed with the second hydrophobic fibers of the lower layer. 4 An upper layer web consisting of a first hydrophobic fiber of 0.8 to 3 denier and 8 to 20 g/ ^m2 , and a second hydrophobic fiber of 15 to 75 g/ ^m2 having water absorbency imparted to the fiber surface. A nonwoven fabric is imparted by laminating a lower layer web in which 10% by weight or more of hydrophobic fibers are 3 to 12 deniers, and treating this laminated web with a high-speed water jet on a support to entangle the fibers of the web. A method for manufacturing an exterior material for a sanitary article, characterized by: