JPH0684597B2 - Polyester fiber paper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyester fiber paper containing polyester short fibers, and more specifically, it is difficult for liquids, gases, bacteria, etc. to pass through even if it is thin, and has high strength and opacity. It relates to a polyester fiber paper which is excellent in softness and has a soft texture.

(Prior art) Recently, the performance required for paper has increased along with the change of lifestyle and the sophistication of technological innovation. Instead of conventional wood pulp, vinylon, nylon, polyacrylonitrile, polyester, etc. Synthetic fibers are being used as a raw material for paper. Paper made of synthetic fibers is generally excellent in moisture resistance, weather resistance, electrical insulation, etc., and is expected to develop in special fields in the future. Among these synthetic fibers, vinylon fibers and polyacrylonitrile fibers have been used in fairly large amounts from the past, but due to the sophistication of the required performance, recently, various paper developments using polyester fibers, which have the best performance, have been developed. Being tried. However, the conventional polyester fiber paper using short polyester fibers has the drawbacks that the weight is high with a high basis weight, the texture of the paper is hard, the cost of the paper material is high, and the cost is high. Therefore, if the weight is reduced and the thickness is reduced, the texture becomes softer and the cost also lowers, but the paper strength becomes low, the opacity deteriorates, and it becomes unsuitable for clothing use. Furthermore, liquids, gases, bacteria, etc. easily pass through, making it unsuitable for surgical gowns, medical materials, and sanitary materials.

On the other hand, Japanese Patent Laid-Open No. 55-110545 proposes an attempt to improve the bulkiness and feel of paper by using a polyester fiber having a T-shaped, Y-shaped, star-shaped or other modified cross-section yarn. However, even if such a modified cross-section yarn is used, the above-mentioned various problems cannot be solved.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned various problems, and even when the paper thickness is thin, the paper strength is high, and liquids, gases, bacteria, etc. are difficult to pass through, and the opacity is high. It is intended to provide a polyester fiber paper which is excellent in and has a soft texture and is suitable for clothes, surgical clothes, medical materials, sanitary materials and the like.

(Means for Solving the Problems) In the present invention, when making polyester fiber paper containing polyester short fibers, the single yarn fineness is 0.1 to 15 denier, the length of the single yarn is 3 to 25 mm, and the fiber crossing is made. It is a polyester fiber paper obtained by blending 5% by weight or more of a polyester short fiber having an unevenness on the surface periphery and a flatness of 2.5 to 8.2 with respect to all active ingredients.

Polyethylene terephthalate is preferable as the polyester used in the present invention, but a part of the acid component and / or diol component thereof is isophthalic acid, sebacic acid, 5-
It may be a copolyester substituted with a dicarboxylic acid such as sodium sulfoisophthalic acid, a diol such as diethylene glycol, 1,4-butanediol, or polyethylene glycol. Further, polybutylene terephthalate, polypropylene terephthalate, etc. are also preferably used. It goes without saying that a matting agent, a fluorescent brightening agent, an antistatic agent, a flameproofing agent and the like may be added to these polyesters.

The polyester fiber contained in the polyester fiber paper of the present invention has a single yarn fineness of 0.1 to 15 denier, preferably 2 to 8
Denier, single yarn length 3-25mm, preferably 5-15
It must be mm. If the single yarn fineness exceeds 15 denier, the paper strength will decrease and the texture will become hard. Single yarn fineness is 0.
If it is less than 1 denier, the dispersibility in water becomes poor and the paper-making property becomes poor. Further, if the length of the single yarn is shorter than 3 mm, the paper strength is insufficient, and if it exceeds 25 mm, the dispersibility in water is deteriorated and quality unevenness occurs.

Furthermore, the polyester short fibers contained in the polyester fiber paper of the present invention need to have a flatness of 2.5 to 8.2, and more preferably in the range of 3.5 to 7.0.
Here, the flatness is represented by A / B when the length of the major axis of the fiber cross section is A and the length of the minor axis is B, as shown in FIG. When the flatness is less than 2.5, paper strength and opacity are not improved, and permeation of liquid, gas, bacteria, etc. cannot be prevented. 2 to 10 show examples of the cross-sectional shape of the polyester short fibers used in the present invention, and since the peripheral edges of the cross-section of the fibers further have irregularities, the opacity is further increased. Further, it is desirable to use a flat hollow fiber as shown in FIG. 6 because the hiding property and bulkiness are further improved.

The polyester fiber paper of the present invention may be a single paper made from such polyester short fibers, other synthetic fibers such as vinylon and nylon, recycled fibers such as rayon, inorganic fibers such as glass and asbestos, and natural fibers such as wood pulp. It may be a mixture of papers with other materials. In particular, when mixed with rayon and pulp, the effect of improving paper strength is remarkable. Above all, if polyester short fibers made of polyester copolymerized with 5-sodium sulfoisophthalic acid are used, the bond strength with pulp and rayon increases, and the paper strength further increases. A small amount of fibrous binder may be added as a binder component. When mixed with other fibers as described above, it is important for achieving the object of the present invention that the above polyester short fibers are contained in an amount of 5% by weight or more based on all components constituting the paper.

Furthermore, at least a part of the above-mentioned polyester short fibers in the present invention can be made into an undrawn yarn and used as a binder.

The polyester fiber paper of the present invention is usually produced by a wet papermaking method, but can also be produced by a dry papermaking method or the like.

(Operation) In the polyester fiber paper of the present invention, 5% by weight of polyester short fibers having a specific single yarn fineness and a single yarn length, and having a flat cross-sectional shape in which irregularities exist in the transverse cross-sectional periphery of the fiber Since the paper is made by containing the above components, the flat short fibers are arranged in the direction parallel to the paper surface in the cross-section long axis direction during the paper making. As a result, the gaps between the fibers on the paper surface are reduced, and the hiding property, that is, the opacity and the permeation resistance of liquids, gases, bacteria, etc. are improved. Furthermore, since the cross-sectional shape of the short fibers is flat, the contact area between the short fibers in the paper is increased, the frictional force is increased when tearing the paper, and the paper strength is improved.

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

The methods for measuring paper strength, water repellency (liquid permeability), pressure loss (gas permeability), opacity, and bending resistance (softness) are as follows.

(1) Paper strength: Measured according to the method of JIS-P-8113 using a constant speed extension type pulling tester.

(2) Water repellency: 0.1 cc of water was dropped on the surface of the paper and the time taken for the entire amount to penetrate into the nonwoven fabric was measured.

(3) Pressure loss: Measure the pressure loss when passing air at 4 cm per second.

(4) Opacity: Measured according to the method of JIS-P-8138.

(5) Bending resistance: measured according to the cantilever method.

Examples 1 to 12, Comparative Examples 1 to 5 Polyethylene terephthalate chips having an intrinsic viscosity of 0.65
It was melted at 300 ° C, discharged through a spinneret having 1200 holes at a temperature of 285 ° C through a nozzle having the shape shown in Fig. 11, and was taken at a speed of 1000 m / min. At this time, by varying the nozzle size and discharge amount, undrawn yarns having a cross-sectional shape shown in FIG. 4 having different flatness and fineness were obtained, and after making a tow of 40 denier and drawing 2.8 times. Free-shrink heat treatment was performed in an atmosphere of 140 ° C to cut into various lengths. The obtained short fibers were dispersed in water so that the fiber concentration was 0.5%, and at the same time, pulp and acrylic ester resin (binder) were added in the following mixing ratio.

Mixing ratio Polyester short fiber: 50% Pulp: 30% Acrylic ester resin: 20% This dispersion is sent to a cylinder paper machine and the basis weight is 50 g /
to obtain a paper m ^2.

Further, the paper component composition after papermaking was treated with acetone which is a solvent of acrylic acid resin, and o-chlorophenol which is a solvent of polyester, and analyzed.

The strength, opacity, pressure loss, softness, and papermaking properties in the papermaking process of the obtained paper were as shown in Table 1.

As is clear from Table 1, the polyester fiber papers of the present invention (Examples 1 to 12) have high paper strength, large opacity and pressure loss, excellent concealing property, low bending resistance and soft texture. The papermaking property was also good.

On the other hand, when the single yarn fineness was less than 0.1 denier (Comparative Example 1), the dispersibility in water was poor and the paper-making property was poor, and a satisfactory paper could not be obtained. On the other hand, when the single yarn fineness exceeded 15 denier (Comparative Example 2), the paper strength was low, the bending resistance was high, and the texture was hard. Further, when the length of the single yarn is less than 3 mm (Comparative Example 3), the paper strength is lowered, and when it exceeds 25 mm (Comparative Example 4), the dispersibility in water is poor and the paper-making property becomes poor, resulting in a paper thickness There were many spots and a satisfactory paper could not be obtained. When the flatness was less than 2.5 (Comparative Example 5), the paper strength was low, the opacity and the pressure loss were low, and the hiding property was poor.

Comparative Example 6 In Example 9, short fiber having a circular cross section was obtained by spinning using a normal circular nozzle, and other conditions were the same as in Example 9 for papermaking.

The strength of the obtained paper is as low as 4.5 kg / 5 cm, the opacity is 58%, and the pressure loss is as low as 10 mmH ₂ O, resulting in poor concealment.
The bending resistance was 6.5 cm and the texture was rather hard.

Examples 13 to 18 and Comparative Examples 7 to 9 In Example 9, nozzles of various shapes (FIGS. 11 and 12) were used.
Nozzle and circular nozzle shown in FIG. 13 and FIG. 13 are used to have the cross-sectional shape and the round cross-sectional shape shown in FIGS. 1, 4 and 6, respectively, and the fineness is 2 denier, Length 10
mm stretched polyester short fibers were obtained.

On the other hand, the spun fibers having the above-mentioned various cross-sectional shapes were cut into a length of 10 mm without being drawn, and the spun fibers were respectively cut into the lengths shown in FIGS.
A polyester unstretched short fiber having a cross-sectional shape and a round cross-sectional shape shown in FIG. 6 and a fineness of 4 denier was obtained.

These polyester stretched short fibers having various cross-sectional shapes and polyester unstretched short fibers are combined as shown in Table 2 and dispersed in water so that the fiber concentration becomes 0.5%,
At the same time, the fibrous polypropylene binder was added. The blending ratios of the polyester stretched short fiber, the polyester unstretched short fiber and the polypropylene binder were as follows.

Blending ratio Polyester stretched short fibers: 55% Polyester unstretched short fibers: 35% Fibrous polypropylene binder: 10% This dispersion is sent to a cylinder paper machine and the basis weight is 50 g /
to obtain a paper m ^2.

The strength, opacity, water repellency, bending resistance, and paper-making property in the paper-making process of the obtained paper were as shown in Table 2.

As is clear from Table 2, the polyester fiber papers (Examples 13 to 18) of the present invention have high paper strength, high opacity and water repellency, excellent hiding power, low bending resistance and feeling. Was soft and had good paper-making properties.

On the other hand, when short fibers having a round cross section were used (Comparative Example 7), the paper strength was low, the opacity and the water repellency were low and the hiding property was poor, and the bending resistance was high and the texture was hard. . Further, when flat fibers having no unevenness were used (Comparative Examples 8 and 9), the effect of improving the hiding property was small.

When the drawn short fibers have a round cross section and the undrawn short fibers have a flat cross section (Examples 13 and 17), conversely, the drawn short fibers have a flat cross section,
When the undrawn short fibers had a round cross section (Examples 14 and 16), the object of the present invention could be achieved and the opacity increased.

Examples 19 to 21, Comparative Examples 10 and 11 Paper was made in the same manner as in Example 2 except that the mixing ratios of polyester short fibers, pulp and acrylic ester resin were changed. The results are shown in Table 3. Less than 5% polyester short fibers (Comparative Examples 10 and 11)
However, paper strength, opacity, pressure loss, bending resistance, and papermaking properties were all insufficient.

When the polyester short fiber content was 5% or more (Examples 19, 20, and 21), the paper strength, opacity, pressure loss, bending resistance, and paper-making property were all improved and were excellent.

(Effects of the Invention) The polyester paper of the present invention has high paper strength, low permeability to liquids, gases, bacteria, etc., high opacity and excellent concealing properties, and yet has a soft texture. . Therefore, it can be preferably used for clothing such as underwear, surgical clothes, medical materials, sanitary materials such as bottom sheets of sanitary napkins, impregnated paper for honeycomb, and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of the cross-sectional shape of a polyester short fiber in which there is no unevenness on the peripheral edge of the cross-section of the fiber, and FIGS. 2 to 10 are polyester short fibers used in the polyester fiber paper of the present invention. Sectional view showing an example of the cross-sectional shape of the fiber,
FIG. 11 is a plan view showing the shape of the nozzle for spinning the fiber having the cross-sectional shape shown in FIG. 4, and FIG. 12 is the nozzle for spinning the fiber having the cross-sectional shape shown in FIG. FIG. 13 is a plan view showing the shape, and FIG. 13 is a plan view showing the shape of a nozzle for spinning the fiber having the cross-sectional shape shown in FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Sakashita 77 Kitayoshida-cho, Matsuyama City, Ehime Prefecture, Teijin Stock Company Matsuyama Factory (72) Inventor, Hirakawa 3-4-1, Omihara, Ibaraki, Osaka Teijin Limited (72) Inventor Kunio Nishimura 3-4-1 Mihara, Ibaraki-shi, Osaka Teijin Ltd. Textile Research Laboratory (56) Reference JP-A-57-139600 (JP, A) JP-A-55-110545 (JP, A) JP-A-57-5915 (JP, A) JP-B 39-16203 (JP, B1)

Claims (3)

[Claims] 1. When making a polyester fiber paper containing polyester short fibers, the single yarn fineness is 0.1 to 15 denier, the length of the single yarn is 3 to 25 mm, and the flatness due to unevenness on the periphery of the cross section of the fiber. Polyester fiber paper made by blending 5% by weight or more of short polyester fibers having a ratio of 2.5 to 8.2 with respect to all active ingredients. 2. The polyester fiber paper according to claim 1, wherein at least a part of the polyester short fibers is an undrawn yarn. 3. The polyester fiber paper according to claim 1, wherein at least a part of the polyester short fibers is a flat hollow fiber.