JPH0978436A - Nonwoven fabric and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Objective] A non-woven fabric that stretches at low stress and has sufficient stretchability in the lateral direction to obtain a stretchable product without pleating wrinkles when laminated with an elastic material. provide. [Composition] 10% by weight of polypropylene A with MFR of 5 to 20 g / 10 min, and MFR of 10% with polypropylene A
Eccentric core-sheath type crimped composite fiber is spun with 20 g / 10 minutes large polypropylene B 90% by weight, collected on a collecting belt, and then entangled by hot embossing to obtain tensile elongation in the transverse direction. Is 150% or more, the maximum tensile load is 400 g / 5 cm or more, and 0 ≦ ε ≦ 50 between the tensile load F (g / 5 cm) and the tensile elongation ε (%), F ≦ ε, 50 ≦ When ε ≦ 100, a nonwoven fabric having a relationship of F ≦ 3 × ε-100 is used as a raw fabric, and the stretching temperature is 130 ° C. in a stretching machine having a roll distance of 5 m.
At the draw ratio of 1.5, the film is stretched in the machine direction so that the width shrinkage amount is 60%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a nonwoven fabric used for medical and hygiene materials such as poultices and disposable diapers, packaging materials and other industrial materials, and a manufacturing method thereof, and particularly excellent in lateral stretchability. Nonwoven fabric and its manufacturing method.

[0002]

2. Description of the Related Art Taking a disposable diaper as an example, such a diaper is usually made of a composite material of an elastic material such as a rubber cord for imparting extensibility to a waist or a crotch and a non-woven fabric having a cloth-like feel. Is used. As a method for producing such a material, conventionally, a method in which a rubber string or the like is passed through a non-woven fabric to make a composite, and as shown in Japanese Patent Publication No. 62-28456, an elastic material is stretched and then a non-woven fabric is laminated to make a composite. However, since the processing is complicated and the elastic cords and elastic materials are used in a contracted state, the composite non-woven fabric becomes pleated and the baby's rash becomes pleated. Tend to cause. Such problems occur due to the lack of extensibility of the non-woven fabric to be composited.

Attempts have also been made to provide the stretchability of nonwoven fabrics. WO94-23109 discloses, as a method for imparting stretchability to a nonwoven fabric, a method in which a nonwoven fabric made of a synthetic resin is heated and stretched at a temperature not higher than the melting point of the resin and not lower than the softening point, but this method is sufficient. A non-woven fabric having excellent extensibility cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-woven fabric having sufficient extensibility in the transverse direction and large elongation under low stress, and a method for producing the same.

[0005]

The nonwoven fabric of the first invention has a tensile elongation in the transverse direction of 150% or more, a maximum tensile load of 400 g / 5 cm or more, and preferably when the longitudinal tensile load is 5% elongation. It is characterized by 800g / 5cm or more. Nonwoven fabric requires some tensile strength in the machine direction, and if it is too stretchable, it will easily lose its shape when wound on a roll during manufacturing. It contracts and becomes difficult to extract, and dimensional stability is impaired. Longitudinal tensile load is 800g / 5c at 5% extension
By setting m or more, such a problem can be solved. The tensile elongation referred to in the present invention means JIS L
It is the elongation obtained by the tensile test specified in 1906.

A second aspect of the present invention is the nonwoven fabric of the first aspect of the present invention, in which the tensile load F (g / 5 cm) and the tensile elongation ε (%) applied to a test piece of 5 cm width in tensile test characteristics (1) When 0 ≦ ε ≦ 50 F ≦ ε (2) When 50 ≦ ε ≦ 100 There is a relationship of F ≦ 3 × ε−100.

In order to obtain the non-woven fabric of the first and second inventions, a third aspect of the present invention is to produce a non-woven fabric of synthetic resin,
The stretching temperature is 20 to 40 ° C. lower than the melting point of the resin, the stretching ratio is 1.4 to 1.8 times, the stretching path length is 2.5 m or more, and the width shrinkage amount is 60% or more in the longitudinal direction. It is characterized by being stretched. Here, the width shrinkage% is
[{(Nonwoven fabric width before stretching)-(Nonwoven fabric width after stretching)} /
(Nonwoven fabric width before stretching)] It is given by 100.

The stretching path length refers to the distance between rolls that gives a speed difference during the stretching process. The synthetic resin used in the present invention may be any fiber-forming resin such as polyolefin, polyester and polyamide. Specific examples of the polyolefin include polyethylene, polypropylene, and copolymers of those monomers with other α-olefins. Examples of polyester include polyethylene terephthalate, and examples of polyamide include nylon. Of these, polyolefin resins are preferred,
Polypropylene is particularly preferred.

The nonwoven fabric used in the present invention may be produced by a spunbond method, a card method or another method, but the stretching treatment according to the present invention causes large width shrinkage and wrinkles. It is desirable to use a non-woven fabric made of crimped yarn having a large tensile elongation or a non-woven fabric having a small aspect ratio of tensile strength because it is easy to do and the transverse strength is easily reduced by the stretching treatment. In particular, it is preferable to use it for the raw fabric obtained from the eccentric core-sheath type crimped composite fiber based on the fourth invention described below, because a synergistic effect makes it possible to obtain a non-woven fabric having better lateral elongation. .

The stretching treatment may be a single-stage stretching or a multi-stage stretching as long as the stretching path length is 2.5 m or more. Further, as a heat source for maintaining the stretching temperature T (melting point −40 ° C.) ≦ T ≦ (melting point −20 ° C.), an oven, an infrared heater, a heat roll, or the like can be used.

A fourth invention is, as another method for obtaining the above-mentioned first and second nonwoven fabrics, a polyolefin resin A having an MFR of 5 to 20 g / 10 minutes, and an MFR of 10 to 10 than that of the resin A.
Polyolefin resin B with a weight ratio of about 20 g / 10 min.
/ B is 10/90 to 20/80 at a ratio of eccentric core-sheath type crimped composite fiber, spun on a collecting belt, and then entangled by an entangling means such as hot embossing. It is characterized by

The eccentricity of the nozzle of the spinneret used in the present invention is 0.5 mm or more, preferably 1.0 mm. The spun filament is cooled with a cooling fluid such as air, and tension is applied to the filament with stretched air to obtain the desired fineness, but the fineness is preferably small in order to further shrink the filament, 3 denier or less, preferably 2 denier or less is desirable.

As the interlacing means, heat embossing, water jet, hot air through, needle punching, etc. can be used. The basis weight is preferably 30 g / m ² or less in order to reduce the stress at the time of low elongation, but a nonwoven fabric having a higher basis weight can be sufficiently used depending on the application. As for the resin A and the resin B, the resin A may be used as a core and the resin B may be used as a sheath, or conversely, the resin A may be used as a sheath and the resin B may be used as a core.

Specific examples of the polyolefin resin used in the present invention include polyethylene, polypropylene, and copolymers of those monomers with other α-olefins. Of these, polypropylene is preferred. The method of measuring MFR (melt flow rate) in the present invention is a method performed according to ASTM D1238.

[0015]

【Example】

Example 1 A spunbonded nonwoven fabric made of polypropylene (melting point 164 ° C.) having a fineness of 3 denier, a basis weight of 15 g / m ² , and a tensile strength per 5 cm of 1920 g in the longitudinal direction and 2160 g in the transverse direction was used as a raw fabric. Using an oven as a heat source and a stretching machine with a roll distance of 5 m between the delivery roll and the take-up roll, the stretching temperature is 130 ° C., the stretching ratio is 1.4, and the film is stretched in the machine direction so that the width shrinkage is 65%. Then, a stretchable nonwoven fabric was obtained. Table 1 shows the stretching conditions and the physical properties of the obtained nonwoven fabric.

Example 2 An extensible nonwoven fabric was obtained in the same manner as in Example 1 except that the draw ratio was 1.5 and the width shrinkage was 69%. Table 1 shows the stretching conditions and the physical properties of the obtained nonwoven fabric. Example 3 An extensible nonwoven fabric was obtained in the same manner as in Example 1 except that the draw ratio was 1.8 and the width shrinkage amount was 81%. Table 1 shows the stretching conditions and the physical properties of the obtained nonwoven fabric.

Example 4 An extensible nonwoven fabric was obtained in the same manner as in Example 1 except that the distance between the rolls was 2.7 m and the draw ratio was 1.5. Table 1 shows the stretching conditions and the physical properties of the obtained nonwoven fabric. Comparative Example 1 An extensible nonwoven fabric was obtained in the same manner as in Example 1 except that the draw ratio was 1.2 and the width shrinkage amount was 50%. Table 2 shows the stretching conditions and the physical properties of the obtained nonwoven fabric.

Comparative Example 2 An extensible nonwoven fabric was obtained in the same manner as in Example 1 except that the stretching temperature was 120 ° C., the width shrinkage amount was 60%, and the stretching ratio was 1.5. Table 2 shows the stretching conditions and the physical properties of the obtained nonwoven fabric.

[0019]

[Table 1]

[0020]

[Table 2]

As can be seen from Tables 1 and 2, the stretching temperature is 20 ° C to 40 ° C rather than the melting point of polypropylene of 164 ° C.
Stretching treatment was carried out in a low range, a stretching ratio of 1.4 to 1.8 times, a distance between rolls (stretching path length) of 2.5 m or more, and a width shrinkage amount after stretching of 60% or more. Examples 1-
Each of the non-woven fabrics of No. 4 has soft touch and good texture, and has a maximum tensile elongation of 150% or more in the transverse direction, the maximum tensile load until breaking reaches 400 g / 5 cm or more, and the tensile elongation ε is 50. %, The tensile load F per 5 cm is 50 g or less, and the tensile elongation ε is 5 when the tensile elongation ε is 100%.
Tensile load F per cm is 3 × 100-100 = 200g
It was below, and the elongation at low stress was also good.

On the other hand, in Comparative Example 1 in which the draw ratio is 1.4 or less and the width shrinkage is 50%, the maximum tensile elongation in the transverse direction is 116%, the elongation in the transverse direction is poor, and the tensile elongation is ε is 5
The tensile load F per 5 cm when the tensile load was 0% was 70 g, and the tensile load F per 5 cm when the tensile load ε was 100% was 870 g, which required a larger tensile load than each of the examples. In other words, the elongation at low stress was poor.

The stretching temperature is 16 which is the melting point of polypropylene.
In Comparative Example 2 lower than 40C by 40C or more, the maximum tensile elongation in the transverse direction was 120%, and the elongation in the transverse direction was poor. Example 5 Mitsui Petrochemical Co., Ltd., MFR (230 ° C., load 2.16 kg) is 10 g by weight of polypropylene (trade name “Hi-Pole”) with a MFR of 5 g / 10 min, and MFR manufactured by the same is 16 g / 10.
And 90 parts by weight of polypropylene (same product) for 0.6 mmφ, 1097 holes, and eccentricity of 1.0 mm were used to perform composite melt spinning at a discharge rate of 1.0 g / min per hole and spinning. The filament of about 2 denier thus prepared was deposited on the collecting surface and then entangled with a hot embossing roll to obtain a stretchable nonwoven fabric having a basis weight of 23 g / m ² . Table 3 shows the results.
Shown in

Here, MFR was measured according to ASTM D1238. Example 6 A polypropylene having the same trade name as that of Example 5 and having polypropylene having an MFR of 20 g / 10 min and 35 g / 10 min polypropylene was used.
Composite melt spinning was performed under the same conditions as in Example 5 using a weight ratio of / 90 to obtain a stretchable nonwoven fabric having the same basis weight of 23 g / m ² .
Table 3 shows the results.

Example 7 Except that the weight ratio was changed to 20/80, polypropylene of the same product as in Example 5 was used, and composite melt spinning was carried out under the same conditions as in Example 5 to give a stretchable nonwoven fabric having a basis weight of 23 g / m ^2. Got
Table 3 shows the results. Comparative Example 3 Composite melt spinning under the same conditions as in Example 5, using polypropylene having the same trade name as that of Example 5, MFR of 16 g / 10 min and polypropylene of 35 g / 10 min in a weight ratio of 10/90. Then, a non-woven fabric having the same basis weight of 23 g / m ² was obtained.
The results are shown in Table 4.

Comparative Example 4 A polypropylene of the same product as in Example 5 was used except that the weight ratio was changed to 30/70, and composite melt spinning was performed under the same conditions as in Example 5 to produce a nonwoven fabric having a basis weight of 23 g / m ² . Obtained. The results are shown in Table 4. Comparative Example 5 A product having the same trade name as that of Example 5, wherein polypropylene having an MFR of 16 g / 10 min and polypropylene having an MFR of 60 g / 10 min were used in a weight ratio of 10/90 and spun under the same conditions as in Example 5. However, yarn breakage occurred, and spinning could not be performed.

[0027]

[Table 3]

[0028]

[Table 4]

As shown in Tables 3 and 4, the polypropylene used in the core has a MFR larger than that used in the sheath by 10 to 20 g / 10 minutes, and the weight ratio of both is 10/90 to 20. In the non-woven fabrics of Examples 5 to 7 used in the ratio of / 80, the maximum tensile elongation in the transverse direction was 150% or more, and the tensile load F per 5 cm when the tensile elongation ε was 50%. Is 50 g or less, the tensile load F per 5 cm when the tensile elongation ε is 100% is 3 × 100-100 = 200 g or less, and the elongation at low stress is good, and the maximum tensile load is 400 g / 5 cm.
The above is reached.

On the other hand, the nonwoven fabric obtained in Comparative Example 3 in which the MFR of the polypropylene used for the core is larger than the MFR of polypropylene used for the sheath by 4 g / 10 minutes and does not reach 10 g / 10 minutes, Tensile elongation of 141%
In addition, the tensile load per 5 cm when the tensile elongation ε is 50% is 65 g, which is inferior to that of each example, and the tensile load per 5 cm when it exceeds 50 g and the tensile elongation ε is 100%. At 235g, the same tensile elongation ε exceeds 200g.
In order to obtain the above, a large tensile load was required as compared with each of the examples.

The nonwoven fabric obtained in Comparative Example 4 in which the weight ratio of polypropylene used in the sheath and the core is 30/70 and exceeds 20/80 is 5 when the tensile elongation ε is 50%.
The tensile load per cm is 69 g, which exceeds 50 g, and the tensile load per 5 cm when the tensile elongation ε is 100%, also exceeds 293 g and 200 g, which is larger than that of each example in order to obtain the same tensile elongation. Tensile load was required.

MF of polypropylene used for the core
R is 50g / from MFR of polypropylene used in sheath
In Comparative Example 5, which was large for 10 minutes or more, spinning could not be performed due to yarn breakage.

Example 8 The nonwoven fabric obtained in Example 5 was used as a raw fabric, this was used as a heat source for a hot plate, and the stretching temperature was 130 ° C. with a stretching machine having a roll distance of 5 m between a delivery roll and a take-up roll. The stretch ratio was set to 1.5, and the stretchable nonwoven fabric was obtained by stretching in the longitudinal direction so that the width shrinkage amount was 60%. Table 5 shows the stretching conditions and the physical properties of the resulting nonwoven fabric.

[Table 5] As can be seen from Table 5, by using the non-woven fabric made of the eccentric core-sheath type crimped composite fiber as the raw fabric of the non-stretched non-woven fabric, a non-woven fabric having further excellent lateral extension could be obtained.

As described above, according to the present invention and the nonwoven fabric obtained by the method of the present invention, the tensile elongation in the transverse direction is 150% or more, the stretchability in the transverse direction is sufficient, and the stress is low. It has a large elongation, and it is possible to obtain an elastic product without pleating wrinkles simply by laminating it with an elastic material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minoru Hisada Minoru 6-1-2 Waki, Waki-cho, Kuga-gun, Yamaguchi Mitsui Petrochemical Co., Ltd.

Claims (12)

[Claims] 1. A synthetic resin having a tensile elongation of 1 in the transverse direction.
A non-woven fabric having a maximum tensile load of 50% or more and a maximum tensile load of 400 g / 5 cm or more. 2. The longitudinal tensile load is 800 g / g at 5% elongation.
The non-woven fabric according to claim 1, which is 5 cm or more. 3. In the tensile test characteristics, between the lateral tensile load F (g / 5 cm) and the tensile elongation ε (%) (1) When 0 ≦ ε ≦ 50 F ≦ ε (2) 50 When ≦ ε ≦ 100, there is a relationship of F ≦ 3 × ε-100, The nonwoven fabric according to claim 1 or 2. 4. A non-woven fabric web made of synthetic resin is stretched at a stretching temperature of 20 to 40 ° C. lower than the melting point of the resin, a stretch ratio of 1.4 to 1.8 times, and a stretch path length of 2.5 m or more. The nonwoven fabric according to any one of claims 1 to 3, wherein the nonwoven fabric is stretched in the longitudinal direction so that the width shrinkage amount is 60% or more. 5. The original fabric is a nonwoven fabric made of crimped yarn.
The non-woven fabric described. 6. A raw material is a polyolefin resin A having an MFR of 5 to 20 g / 10 min and an MFR of 10 to 20 g / 10 from that of the resin A.
The weight ratio A / B of the polyolefin resin B is about 1
A non-woven fabric which is spun into an eccentric core-sheath type crimped composite fiber at a ratio of 0/90 to 20/80, collected on a collection belt, and then entangled by an entanglement means such as hot embossing. The non-woven fabric according to claim 4. 7. The synthetic resin is a polyolefin.
The nonwoven fabric according to any one of claims 1 to 5. 8. The non-woven fabric according to claim 6, wherein the polyolefin is polypropylene. 9. A non-woven fabric sheet made of a synthetic resin is stretched at a stretching temperature of 20 to 40 ° C. lower than the melting point of the resin, a stretch ratio of 1.4 to 1.8 times, and a stretch path length of 2.5 m or more. The method for producing a non-woven fabric according to any one of claims 1 to 3, characterized in that the nonwoven fabric is stretched in the machine direction so that the width shrinkage amount is 60% or more. 10. The method for producing a non-woven fabric according to claim 9, wherein the synthetic resin is polyolefin. 11. A raw material is a polyolefin resin A having an MFR of 5 to 20 g / 10 min, and an MFR of 10 to 20 g /
A polyolefin resin B having a large size of about 10 minutes is spun into an eccentric core-sheath type crimped composite fiber at a weight ratio A / B of 10/90 to 20/80 and collected on a collecting belt, followed by heat embossing. 10. The method for producing a non-woven fabric according to claim 9, which is a non-woven fabric formed by a entanglement process such as a entanglement means. 12. A polyolefin resin A having an MFR of 5 to 20 g / 10 minutes and a polyolefin resin B having an MFR larger than that of the resin A by about 10 to 20 g / 10 minutes and a weight ratio A / B of 10/9.
An eccentric core-sheath type crimped composite fiber is spun at a ratio of 0 to 20/80, collected on a collection belt, and then entangled by an entanglement means such as hot embossing. The non-woven fabric according to any one of claims.