JPH09279449A - Laminated nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonwoven fabric comprising short fibers made of conjugate filament yarns of excellent cooling disposition, spinnability and drawability following their delivery from a spinneret, good in biodegradability which is controllable, rich in both moisture and water absorbability, and having enough mechanical strength to stand its practical use. SOLUTION: First, a melt conjugate spinning is conducted to produce a sheath-core type conjugate fiber made up of core component consisting of a 1st biodegradable aliphatic polyester and sheath component consisting of a 2nd biodegradable aliphatic polyester lower in melting point than the 1st polyester. Subsequently, the conjugate fibers are drawn, the resultant oriented filament yarns are then mechanically crimped and cut to a specified length into short fibers, which are then carded into a short fiber web, which is, in turn, laminated with a natural fiber web followed by subjecting both the webs to ultrasonic fusing treatment into integration through partial fusing, thus affording the objective laminated nonwoven fabric.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a medical / hygiene material,
The present invention relates to a laminated non-woven fabric suitable for a wide range of applications where biodegradability and water absorption are desired, such as daily life materials and general industrial materials, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Conventionally, as non-woven fabrics having biodegradability, for example, viscose short fiber non-woven fabrics obtained by a dry method or a solution dipping method, cupra rayon long fiber non-woven fabrics and viscose rayon long fiber non-woven fabrics obtained by a wet method. Nonwoven fabrics made of natural chemical fibers such as chitin and collagen, spunlace nonwoven fabric made of cotton, and the like are known. However, since these biodegradable nonwoven fabrics have low mechanical strength and are hydrophilic, the mechanical strength upon water absorption / wetting is significantly reduced. Further, since these non-woven fabrics are non-thermoplastic in nature, they have problems such as lack of thermal adhesiveness and thermoformability.

As a biodegradable non-woven fabric which solves such a problem, there is disclosed in Japanese Patent Laid-Open No. 93318/1993 or Japanese Patent Laid-Open No. 5-93318.
Japanese Patent No. 195407 discloses a non-woven fabric using a biodegradable thermoplastic polymer. But these are
The spun yarn during production was inferior in the cooling property, spinnability, and stretchability, and, since it was a fully melted type in the hot pressing process, the resulting nonwoven fabric was inferior in mechanical properties and flexibility. .

Such problems occur in the process of producing a biodegradable nonwoven fabric because the melting point and crystallization temperature of a biodegradable polymer are generally low and the crystallization rate is slow. That is, adhesion between yarns occurs during cooling / thinning after melt spinning, and operability is significantly impaired in the drawing / crimping step in the next step.
Moreover, in the conventional manufacturing method as described above, control of biodegradation performance is possible to some extent by changing the type of polymer to be applied, fineness, orientation degree of fiber, etc., but delicate control is possible. Was impossible.

Further, although a nonwoven fabric formed of fibers made of a biodegradable thermoplastic polymer alone has excellent mechanical properties, it is inferior in hygroscopicity and water absorption and its use is limited. As a method for improving this, it is conceivable to laminate natural fibers and the like having excellent water absorption, but partial heat fusion is performed by laminating a web made of a biodegradable thermoplastic polymer and a web made of natural fibers. According to the thermocompression bonding apparatus using a hot embossing roll which is usually applied when applied, the adhesive strength between the two webs is weak and the obtained laminated nonwoven fabric cannot withstand use at all.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, has excellent cooling properties, spinnability and stretchability of spun yarns, has good biodegradability, and is controllable. Accordingly, the present invention aims to provide a laminated nonwoven fabric which is rich in hygroscopicity and water absorption and has sufficient strength to withstand actual use, and a method for producing the same.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have reached the present invention. That is, the present invention has the following structures.

(1) A short fiber web made of composite short fibers and a natural fiber web made of natural fibers are laminated and integrated by partial ultrasonic fusion, and the composite short fibers have biodegradability. It has a core-sheath type composite cross section formed of a core component made of a first aliphatic polyester and a sheath component made of a second aliphatic polyester having a lower melting point than the core component and having biodegradability. Laminated non-woven fabric characterized by.

(2) A core component made of a first aliphatic polyester having biodegradability and a sheath component made of a second aliphatic polyester having a lower melting point than the core component are used. The core-sheath type composite fiber is melt-combined and then drawn, and the resulting drawn yarn is mechanically crimped and then cut into a predetermined length to form a short fiber. A laminated non-woven fabric characterized by forming a fibrous web, laminating a natural fiber web made of natural fibers on the short fibrous web, and then subjecting the two webs to partial fusion by ultrasonic fusion treatment to integrate them. Manufacturing method.

As described above, since the short fiber web constituting the laminated nonwoven fabric of the present invention is formed of the core-sheath type composite short fibers composed of two components having different melting points,
The spun yarn has excellent cooling properties, spinnability, stretchability and biodegradability.

In addition, the laminated nonwoven fabric of the present invention is made to absorb water by natural fibers and to reinforce the characteristic of natural fibers that mechanical strength when wet is poor by a short fiber web. That is, by laminating the short fiber web and the natural fiber web, it is possible to have both water absorption and mechanical properties. Moreover, since the short fiber web is composed of an aliphatic polyester polymer and the natural fiber web is composed of a degradable material such as cotton, all the constituent materials of the laminated nonwoven fabric of the present invention can be decomposed in a natural environment. Is.

Further, since the laminated nonwoven fabric of the present invention is formed by integrating the short fiber web and the natural fiber web by ultrasonic fusion, it is excellent in peel strength between both webs and can withstand practical use sufficiently. Is.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The laminated nonwoven fabric of the present invention is formed by laminating a short fiber web made of composite short fibers and a natural fiber web made of natural fibers.

First, the short fiber web of the present invention will be described. The short fibers applied in the present invention include a core component made of a first aliphatic polyester having biodegradability and a sheath component made of a second aliphatic polyester having a biodegradability lower than the core component. Is a composite short fiber formed from

First and second constituents of the core and sheath components
Examples of the biodegradable aliphatic polyester include poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, or a copolymer of repeating unit elements constituting them. In addition, poly (ω-caprolactone), poly (ω-propionate such as poly (β-propiolactone),
-Hydroxyalkanoate) and poly-3-
Hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaproate, poly-3
-Poly (β-hydroxyalkanoate) such as hydroxyheptanoate and poly-3-hydroxyoctanoate, and repeating unit elements and poly-constituting them
Examples thereof include copolymers with repeating unit elements constituting 3-hydroxyvalerate and poly-4-hydroxybutyrate. In addition, as a polycondensate of diol and dicarboxylic acid, for example, polyethylene oxalate,
Polyethylene succinate, polyethylene adipate,
Polyethylene azetate, polybutylene oxalate,
Polybutylene succinate, polybutylene adipate,
Examples thereof include polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and copolymers of repeating unit elements constituting these. Further, a plurality of the above aliphatic polyesters may be blended and used. Among the above-mentioned aliphatic polyesters, polybutylene succinate, polyethylene succinate and polybutylene adipate are particularly preferable from the viewpoint of spinnability and biodegradability, and more particularly, butylene succinate as a main repeating unit and ethylene succinate. A copolyester obtained by copolymerizing nate or butylene adipate is preferable. In the present invention, of the two polymers selected from the above aliphatic polyesters, the polymer with the higher melting point is placed in the core,
The polymer with the lower melting point is placed in the sheath.

Incidentally, the aliphatic polyester is generally
The higher the melting point, the better the cooling properties, spinnability and stretchability of the spun yarn, but the poorer the biodegradability due to the higher crystallinity. Conversely, the lower the melting point, the higher the melting point of the spun yarn. Although it is inferior in cooling property, spinnability and stretchability, it has excellent biodegradability due to its low crystallinity. For example, when the fiber cross section is composed of a component single phase having a relatively high melting point, the target biodegradability cannot be obtained, although the spinnability and the non-woven fabric are excellent. On the other hand, when the cross-section of the fiber is composed of a single component phase having a relatively low melting point, the meltability of the spun yarn is inferior in the cooling property during melt spinning, and a nonwoven fabric cannot be obtained.

In the present invention, for example, even if the sheath component is a polymer having poor cooling properties and stretchability, by using a polymer having a relatively high melting point as the core component, the cooling properties of the spun yarn, The stretchability can be improved. Further, even if the core component is a polymer having poor biodegradability, by compositing a polymer having a relatively low melting point and being excellent in biodegradability, the core component is left behind in a state where the fineness is extremely fine. As a result, the biodegradability of the nonwoven fabric is excellent.

Therefore, polybutylene succinate is used as the core component, and ethylene succinate or butylene adipate is added to the butylene succinate so that the copolymerization ratio of the butylene succinate is 70 to 90 mol% as the sheath component. It is preferable to use a copolyester obtained by copolymerizing the above. When the copolymerization amount ratio of butylene succinate is less than 70 mol%, the biodegradability is excellent, but the cooling property, spinnability and stretchability of the spun yarn are poor, and the target short fibers can be obtained. There will be no. vice versa,
If it exceeds 90 mol%, the cooling and spinnability of the spun yarn,
Although it is excellent in stretchability, it is inferior in biodegradability and is not the object of the present invention.

In the present invention, the above-mentioned aliphatic polyester applied to the core component and the sheath component has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more. However, they are good in terms of spinnability and characteristics of the obtained yarn. Further, it may be chain-extended with a small amount of diisocyanate or tetracarboxylic dianhydride in order to increase the degree of polymerization.

In the present invention, the core component and / or the sheath component described above may be added, if necessary, to
For example, matting agents, pigments, light stabilizers, antioxidants and the like can be added within a range that does not impair the effects of the present invention.

Particularly, in the present invention, in order to improve the cooling property of the spun yarn in the production of short fibers, it is preferable that a crystal nucleating agent is added to at least the sheath component among the constituent components. . Addition of a nucleating agent can prevent adhesion between spun yarns even for a low-crystalline polymer that is hard to solidify after melt spinning. Here, the crystal nucleating agent is a powdered inorganic substance, and is not particularly limited unless it dissolves in the melt, but talc, calcium carbonate, titanium oxide, boron nitride, silica gel, magnesium oxide or A mixture of these is preferably used.

When the crystal nucleating agent is added, the amount of the crystal nucleating agent added to the core component is QA (% by weight), and the amount of the crystal nucleating agent added to the sheath component is QB (% by weight). It is preferable that it is added so as to satisfy the expressions (1) and (2). [(ΔTA + ΔTB) / 100] −2 / 3 ≦ QA + QB ≦ [(ΔTA + ΔTB) / 100] +4 (1) QA ≦ QB (2) where ΔTA = melting point of core component−crystallization of core component Temperature ΔTB = melting point of sheath component−crystallization temperature of sheath component When the total amount of crystal nucleating agent QA + QB (% by weight) exceeds the upper limit defined by the formula (1), the effect of cooling the spun yarn is high. However, this is not preferable because the spinnability is deteriorated and the mechanical properties of the obtained short fibers and thus the nonwoven fabric are poor. On the contrary, if the total amount of the crystal nucleating agent QA + QB (% by weight) becomes lower than the lower limit defined by the equation (1), the cooling property of the spun yarn is deteriorated and adhesion occurs between the spun yarns. However, it becomes difficult to obtain the target short fiber. When the amount QA (wt%) of the crystal nucleating agent added to the core component is larger than the amount QB (wt%) of the crystal nucleating agent added to the sheath component, the cooling property of the core component is further improved. However, the cooling property of the sheath component is lowered, and this tends to cause adhesion between spun yarns, which is not preferable.

In the present invention, the viscosities of the core component and the sheath component are not particularly limited, but it is preferable that the viscosity of the core component is higher than the viscosity of the sheath component. This is because the low-viscosity component generally acts in the composite spinning of the thermoplastic resin so as to cover the high-viscosity component. That is, in the present invention, by making the core component highly viscous, it becomes suitable for maintaining the core-sheath form in the cross section of the fiber.

Therefore, the melt flow rate value (hereinafter referred to as MFR value) of the polymer applied in the present invention is 5 to 50 g / 10 minutes for the core component and 10 to 70 g / 1 for the sheath component.
It is preferably 0 minutes. However, the MF in the present invention
The R value is measured according to the method described in ASTM-D-1238 (E). MFR value of core component is 5g / 1
Less than 0 minutes and / or MFR value of sheath component is 10 g / 10
If the amount is less than the minute, the viscosity is too high, and the spun yarn cannot be thinned smoothly, resulting in impaired operability, and the obtained fiber has a large fineness and poor uniformity. Conversely, the MFR value of the core component is 50 g / 10 minutes and /
Or, when the MFR value of the sheath component exceeds 70 g / 10 minutes,
Since the viscosity is too low, not only the composite cross section becomes unstable, but also yarn breakage occurs in the spinning process, impairing operability, and the resulting nonwoven fabric has poor mechanical properties. For these reasons, the MFR value of the core component is 10
~ 45g / 10min, MFR value of sheath component is 15 ~ 65g /
More preferably, it is 10 minutes.

The composite staple fibers applied to the present invention preferably have a core component / sheath component composite ratio of 1/3 to 3/1 (weight ratio). If the composite ratio is out of this range, the spinnability of the spun yarn cannot be satisfied together with the cooling property, spinnability, stretchability and biodegradability, and further, instability of the fiber cross-sectional shape is induced. Therefore, it is not preferable. For example, when the composite ratio of the core component / the sheath component exceeds 1/3, the biodegradability is excellent, but the cooling property, spinnability and stretchability of the spun yarn are poor. On the other hand, when the composite ratio of the core component / the sheath component exceeds 3/1, the spun yarn has excellent cooling properties, spinnability and stretchability, but poor biodegradability. Further, for example, when the core component is a polymer having poor biodegradability, the biodegradation rate can be accelerated by increasing the composite ratio of the sheath component. For this reason, more preferably 1 /
2.5-2.5 / 1 (weight ratio) is good.

In the present invention, the single yarn fineness of the composite staple fiber is preferably 1.5 to 10 denier. 1.5
When it is less than denier, the spinneret becomes complicated, the number of yarn breakages in the spinning process increases, the production amount decreases, and the fiber cross-sectional shape becomes unstable. On the other hand, when it exceeds 10 denier, the spun yarn has poor cooling properties and biodegradability. For this reason, 2 to 8 denier is more preferable.

As described above, the short fiber web applied to the present invention is formed of the core-sheath type composite short fibers composed of the core component and the sheath component made of biodegradable aliphatic polyester having different melting points. It is a web that, by combining the composite ratio of both components, the single yarn fineness, etc., the required cooling property, spinnability and stretchability of the spun yarn can be obtained, and further the biodegradability can be controlled. You can do it.

Next, the natural fiber web of the present invention will be described. As the natural fiber applied in the present invention,
Cotton, ramie, silk fibers cut into short fibers and the like are preferable, and short fiber webs are prepared by using these natural fibers alone or in combination. Here, examples of the cotton fiber include combed yarn that has not been subjected to bleaching, bleached cotton that has been bleached, and fluff obtained from woven fabrics and knits.

The short fiber web and the natural fiber web in the present invention are parallel webs arranged in the traveling direction of the card machine, crosslaid webs of parallel webs, randomly arranged random webs or semi-random webs arranged in medium. It may be any of the above, and can be appropriately selected depending on the intended use. In particular, when used for clothing, it is preferable to use a card web having a strength / longitudinal strength ratio of about 1/1 in terms of strength as a nonwoven fabric.

The laminated nonwoven fabric of the present invention is obtained by laminating a short fiber web and a natural fiber web, and the lamination ratio of the natural fiber web and the short fiber web is from 10/90 to 90/1.
It is preferably 0 (% by weight). When the content of natural fibers is less than 10% by weight, the laminated nonwoven fabric has excellent mechanical properties, but the hygroscopicity and water absorption cannot be sufficiently improved, and the purpose of laminating the natural fibers cannot be achieved. Not preferable. On the other hand, if the natural fiber content exceeds 90% by weight, the hygroscopicity and water absorption are excellent, but the mechanical properties are impaired, which is not preferable. For these reasons,
Lamination ratio of natural fiber web and short fiber web is 20/8
It is more preferably 0 to 80/20 (% by weight).

The laminated nonwoven fabric of the present invention is one in which the laminated short fiber web and natural fiber web are integrated by partial ultrasonic fusion. That is, in a partial fusion zone formed by using an ultrasonic fusion machine to be described later, since the composite short fibers are heat-melted and embedded inside the natural fiber, the short fiber web and the natural fiber web are And are fused together. As a result, the short fiber web and the natural fiber having no thermal adhesiveness can be integrated with each other with an adhesive force sufficient for practical use.

Next, a method for manufacturing the laminated nonwoven fabric of the present invention will be described. First, the production of the short fiber web applied to the present invention can be carried out using an ordinary composite spinning apparatus and drawing apparatus. That is, the core component and the sheath component made of the above-mentioned biodegradable polymer are melted and individually weighed, and this is mixed at the above-mentioned composite ratio through a composite spinneret capable of forming a core-sheath composite cross section. And the spun yarn is cooled by a known cooling device using a cooling air flow or the like. Then
It is wound up as an undrawn yarn with a take-up roll at a speed of 800 to 2500 m / min, and this undrawn yarn is drawn at a predetermined draw ratio between drawing rolls having different peripheral speeds. Here, the number of stretching rolls and the stretching temperature in the stretching step may be appropriately selected. For example, in the case of stretching the fineness, it is necessary to increase the number of stretching rolls and further perform hot stretching. Then, the obtained drawn yarn is crimped with a stuffer box and then cut into a predetermined length to obtain short fibers. Although the above-described method is a two-step method, short fibers can also be obtained by a one-step method, that is, a so-called spin draw method in which undrawn yarn is continuously drawn without being wound up.

Further, in the present invention, as described above,
It is preferable to add a nucleating agent to the polymer used. Thereby, the cooling property of the spun yarn during the melt spinning can be improved. The crystal nucleating agent is added in the polymerization step or the melting step. At this time, it is preferable to disperse the nucleating agent as uniformly as possible in order to improve the mechanical performance and the uniformity of the obtained yarn.

Next, the obtained short fibers are carded by a known card machine to prepare a short fiber web having a predetermined weight. Then, a natural fiber web separately prepared by a conventional method is laminated on the obtained short fiber web, and ultrasonic fusion treatment is applied to this to integrate them to obtain a laminated nonwoven fabric.

When performing the ultrasonic fusing treatment, it is composed of an ultrasonic oscillator generally called a horn having a frequency of about 20 kHz, and a pattern roll having a convex projection in the form of dots or bands on the circumference. The device is adopted. The pattern roll is disposed below the ultrasonic oscillator, and the laminated nonwoven fabric can be partially heat-sealed by passing the laminated nonwoven fabric between the ultrasonic oscillator and the pattern roll. There may be one row or a plurality of rows of convex protrusions arranged on this pattern roll, and when the arrangement is a plurality of rows, either parallel or staggered arrangement may be used.

More specifically, air pressure is used to press the roll, and the linear pressure at which the horn contacts the roll is 1.0 to 5
It is preferably in the range of 0 kg / cm. Linear pressure is 1.
If it is less than 0 kg / cm, the pressing force becomes insufficient with respect to the thickness of the laminated non-woven fabric and the peel strength of the laminated non-woven fabric becomes small, which is not preferable. On the contrary, when the linear pressure exceeds 50 kg / cm, the pressure is applied to the fusion-bonded portion too much, and the fusion-bonded portion is also formed into a film, which similarly lowers the adhesive strength, which is not preferable.

In the present invention, before the natural fiber web and the short fiber web are laminated, the short fiber web is preliminarily subjected to a temporary heat press bonding process, a hot air bonding process or a three-dimensional entanglement process, and the natural fiber web is three-dimensionally entangled. It can also be processed. Accordingly, when the two webs are stacked, the shape of each web can be favorably maintained.

The unit weight of the laminated nonwoven fabric of the present invention is not particularly limited because it is selected according to the purpose of use,
Generally, the range of 10 to 150 g / m ² is preferable, and the range of 15 to 70 g / m ² is more preferable. When the basis weight is less than 10 g / m ² , flexibility and biodegradation rate are excellent, but mechanical strength is poor and it is not practical.
On the other hand, when the basis weight exceeds 150 g / m ² , the nonwoven fabric has a hard texture and is inferior in flexibility.

[0039]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

In the examples, each physical property value was measured by the following methods.

Melt flow rate value (g / 10 minutes);
The temperature was measured at 190 ° C. according to the method described in ASTM-D-1238 (E). (Hereinafter referred to as MFR value)

Melting point (° C.); maximum value of melting endothermic curve obtained by measurement using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. with a sample weight of 5 mg and a heating rate of 20 ° C./min. Was given as the melting point (° C.).

Crystallization temperature (° C.): Using a differential scanning calorimeter DSC-2 manufactured by PerkinElmer, and weighing a sample of 5 m
g, the temperature giving the maximum value of the solidification exothermic curve obtained by measuring the cooling rate at 20 ° C./min was defined as the crystallization temperature (° C.).

Coolability: The spun yarn was visually inspected and evaluated according to the following three grades. ◯: No adhesion thread is observed. Δ: A small amount of adhesive thread is recognized. X: Most of them are in close contact.

Spinnability: Good; no yarn breakage occurs, and spinning operability is good. X: Thread breakage occurs frequently and spinning operability is poor.

Stretchability: Good: Stretching fluff is not generated and stretching operability is good. X: Stretching fuzz occurs frequently and stretching is impossible.

-Basis weight (g / m ² ); 10 pieces of a sample having a sample length of 10 cm and a sample width of 10 cm were prepared from a standard sample, and after equilibrating water, the weight (g) of each sample piece was weighed. Then, convert the average value of the obtained values per unit area,
The basis weight (g / m ² ) was used.

Strength of non-woven fabric (kg / 5 cm width); JI
It was measured according to the method described in S-L-1096A. That is, a sample piece 1 having a sample length of 20 cm and a sample width of 5 cm
A zero point was created, and a tensile speed of 1 was set for each sample piece in the longitudinal direction of the nonwoven fabric using a constant-speed extension-type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.).
It was stretched at 0 cm / min, and the average value of the load values at cutting obtained was taken as the strength (kg / 5 cm width).

Biodegradability: 6 is obtained by embedding a non-woven fabric in soil.
If the nonwoven fabric does not retain its shape after a month, or if the strength is reduced to 50% or less of the initial strength value before embedding even if it retains its shape, the biodegradation performance is The biodegradability was evaluated as poor (; x) if the strength was more than 50% of the initial strength before embedding.

Water absorption (mm): JIS-L-1096
It was measured according to the Bayrec method described in 1. That is, five sample pieces having a sample length of 20 cm and a sample width of 2.5 cm were prepared, and each sample piece was pinned on a horizontal bar supported at a constant height on a water tank containing water at 20 ± 2 ° C. And hang it. Align the lower end of the sample piece in a line and lower the horizontal bar,
Make sure that m just submerges in water. The rise height (mm) of water after standing for 10 minutes was measured, and the average value was taken as water absorbency (mm).

Example 1 A core component having an MFR value of 20 g / 10 min and a melting point of 114
Polybutylene succinate having a crystallization temperature of 75 ° C.
As a sheath component, MFR value is 30g / 10min and melting point is 102
Using a copolymer of butylene succinate / ethylene succinate = 85/15 mol% at a crystallization temperature of 52 ° C. and a crystallization temperature of 52 ° C., a short fiber web composed of core-sheath type composite short fibers was produced. That is, the core component and the sheath component were melted at a temperature of 180 ° C. using separate extruder type melt extruders, and a spinneret having a core-sheath composite cross section was used, and single hole discharge rate = 1.02 g / min. , Composite ratio (core component / sheath component) = 1/1
Melt spinning was performed under the condition of (weight ratio). After cooling this spun yarn with a cooling device, an oil agent is applied, and the speed is 800
An undrawn yarn having a fineness of 11.5 denier was obtained through a take-up roll of m / min. A plurality of the obtained unstretched yarn bundles were bundled, stretched at a stretching ratio of 4.0 times under the condition that the stretching temperature was room temperature, and then crimped with a stuffer box at 15 pieces / inch, and then 51 mm. Cut, brand 3d x 5
1 mm short fibers were obtained. This short fiber was supplied to a parallel card machine to prepare a card web having a basis weight of 25 g / m ² .

On the other hand, as a natural fiber web made of natural fibers, a bleached cotton cloth was used, and a card web having a basis weight of 25 g / m ² was prepared by a random card machine. Next, a short fiber web made of core-sheath type composite short fibers and a natural fiber web made of bleached cotton are laminated and subjected to fusion processing by an ultrasonic fusion device to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ^2. It was As the fusion processing condition, the ultrasonic oscillation frequency is set to 1
The roll was set to 9.7 kHz, and a roll having a convex portion having an area of 0.6 mm ² was used, and the pressure contact area ratio of the convex portion was 15% and the linear pressure was 2.0 kg / cm. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Example 2 Melt spinning was performed at a single hole discharge rate of 0.40 g / min and a composite ratio (core component / sheath component) = 1/3 (weight ratio), and a single yarn fineness of 4.6 denier was measured. A core-sheath type composite short fiber was produced under the same conditions as in Example 1 except that a drawn yarn was obtained, drawn at a draw ratio of 3.2 and cut into 38 mm. The obtained short fibers had a brand of 1.5 d × 38 mm. This short fiber is fed to a parallel card machine and the basis weight is 25 g /
An m ² card web was created.

Further, as in Example 1, the basis weight is 25.
A card web made of bleached cotton of g / m ² was prepared. Next, a short fiber web made of core-sheath type composite short fibers and a natural fiber web made of bleached cotton are laminated and subjected to a fusion processing with an ultrasonic fusion device to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ^2. It was The fusion processing conditions were the same as in Example 1. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Example 3 Single-hole discharge amount = 4.10 g / min, melt spinning was carried out at a composite ratio (core component / sheath component) = 3/1 (weight ratio), and an undrawn yarn having a single yarn fineness of 46 denier. Example 1 except that the above was obtained and stretched at a stretch ratio of 4.8 times and cut into 76 mm.
Under the same conditions as above, a core-sheath type composite staple fiber was produced. The obtained short fibers had a brand of 10 d × 76 mm. This short fiber is fed to a parallel card machine and the basis weight is 25 g / m ²
Created a card web.

Further, as in Example 1, the basis weight is 25
A card web made of bleached cotton of g / m ² was prepared. Next, a short fiber web made of core-sheath type composite short fibers and a natural fiber web made of bleached cotton are laminated and subjected to a fusion processing with an ultrasonic fusion device to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ^2. It was The fusion processing conditions were the same as in Example 1. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Example 4 A staple fiber web composed of core-sheath type composite staple fibers having a basis weight of 10 g / m ² obtained under the same conditions as in Example 1 and a basis weight of 4
Laminated with a natural fiber web made of 0 g / m ² of bleached cotton, and fusion-bonded with an ultrasonic fusion device to give a basis weight of 50.
g / m ² of the laminated nonwoven fabric was obtained. Example 1 is the fusion processing conditions.
It carried out on the same conditions as. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Example 5 A staple fiber web composed of core-sheath type composite staple fibers having a basis weight of 40 g / m ² obtained under the same conditions as in Example 1 and a basis weight of 1
Laminated with a natural fiber web made of 0 g / m ² of bleached cotton, and fusion-bonded with an ultrasonic fusion device to give a basis weight of 50.
g / m ² of the laminated nonwoven fabric was obtained. Example 1 is the fusion processing conditions.
It carried out on the same conditions as. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Comparative Example 1 A staple fiber web made of core-sheath type composite staple fibers having a basis weight of 25 g / m ² obtained under the same conditions as in Example 1 and a basis weight of 2
A natural fiber web made of 5 g / m ² of bleached cotton was laminated and heat-bonded with a hot embossing roll to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ² . As the heat-sealing processing conditions, a roll having a convex portion with an area of 0.6 mm ² is used, and the pressing area ratio of the convex portion is 15% and the linear pressure is 50 kg / c.
m at a processing temperature of 90 ° C. Table 1 shows the operability, the physical properties of the laminated nonwoven fabric, and the biodegradability of the core-sheath type composite staple fiber production.

Comparative Example 2 Using the same core component as in Example 1, single-hole discharge rate = 0.97 g / through a spinneret whose fiber cross section is a single-phase cross section.
Melt-spun under the conditions of minutes. That is, the core component was heated at a temperature of 180 ° C. using an extruder type melt extruder.
Melted and melt-spun through a spinneret having a single-phase cross-section, the spun yarn is cooled in a cooling device, and then an oil agent is applied. The speed is 800 m / min and the fineness is obtained through a take-up roll. To obtain 10.9 denier undrawn yarn. A plurality of the obtained unstretched yarn bundles were bundled, stretched at a stretch ratio of 3.8 times under the condition of a stretching temperature of room temperature, and then crimped to 14 mm / inch with a stuffer box. It cut | disconnected and obtained the short fiber of brand 3dx51mm. This short fiber was supplied to a parallel card machine to prepare a card web having a basis weight of 25 g / m ² .

Further, as in Example 1, the basis weight is 25
A card web made of bleached cotton of g / m ² was prepared. Then, a web made of single-phase short fibers and a natural fiber web made of bleached cotton were laminated and subjected to a fusion processing with an ultrasonic fusion device to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ² . The fusion processing conditions were the same as in Example 1.
Table 1 shows the operability, the physical properties of the laminated non-woven fabric, and the biodegradability of the single-phase short fiber production.

Comparative Example 3 A short fiber web composed of core-sheath type composite short fibers having a basis weight of 50 g / m ² obtained under the same conditions as in Example 1 was ultrasonically fused without laminating a natural fiber web. Fusion processing was performed with the device to obtain a non-woven fabric. The fusion processing conditions were the same as in Example 1. Operability of short fiber production and physical properties of non-woven fabric,
The biodegradability is shown in Table 1.

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[Table 1]

As is clear from Table 1, Example 1 is a laminated non-woven fabric composed of the core-sheath type composite staple fiber of the present invention and the natural fiber, and therefore, the cooling property in the production of the core-sheath type composite staple fiber. The spinnability and stretchability were also good. Further, since the method of laminating the core-sheath type composite short fibers and the natural fibers is ultrasonic fusion, the adhesive force between the two components is also strong, and the resulting laminated nonwoven fabric is excellent in mechanical performance and water absorption. there were. When this laminated non-woven fabric was embedded in soil for 6 months and then excavated and observed, it was confirmed that the non-woven fabric did not retain its shape and had good biodegradability.

In Example 2, although the ratio of the sheath component was large, the fineness was small and the core-sheath type composite short fibers were applied. Therefore, as in Example 1, when the core-sheath type composite fiber was produced. The cooling property, spinnability, and stretchability were also good. Further, the obtained laminated nonwoven fabric was excellent in mechanical performance and water absorption. Regarding the biodegradability of this laminated non-woven fabric, a better result was obtained than the laminated non-woven fabric obtained in Example 1 because the ratio of the sheath component was large.

In Example 3, since the ratio of the core component is large and the core-sheath type composite staple fiber is applied, the core-sheath type composite fiber is the same as in Example 1 although the fineness is large. The cooling property, spinnability, and stretchability during the production of were also good.
Further, the obtained laminated nonwoven fabric was excellent in mechanical performance and water absorption. The biodegradability of this laminated nonwoven fabric was also good.

In Example 4, since the same two webs as those in Example 1 were laminated so that the lamination ratio was rich in natural fibers, the mechanical performance was slightly inferior to that in Example 1, but the water absorption and rawness were improved. Even better results were obtained for degradability.

In Example 5, since the same two webs as in Example 1 were laminated so that the lamination ratio was rich in the core-sheath type composite short fiber, the water absorption and biodegradability were slightly higher than those in Example 1. Although inferior, better results were obtained in mechanical performance.

Although it was attempted to measure the delamination strength of the non-woven fabrics obtained in each of the examples, the partial adhesion by ultrasonic waves was so strong that they could not be peeled off.
The measurement could not be performed.

On the other hand, in Comparative Example 1, the same two webs as in Example 1 were integrated by a heat fusion apparatus using a hot embossing roll which is outside the scope of the present invention, so that the two components The adhesive strength was so weak that it could not withstand actual use.

In Comparative Example 2, the same core component as in Example 1 was used, but since the fiber cross-section was a single phase type outside the scope of the present invention, the resulting nonwoven fabric was excellent in mechanical performance. However, when the non-woven fabric was buried in the soil for 6 months, and then excavated and observed, the non-woven fabric form was maintained, and the strength of the non-woven fabric was 91% before the embedding, and the biodegradability was extremely poor. .

In Comparative Example 3, although the same short fiber web as in Example 1 was used, but the natural fiber web was not laminated, the obtained nonwoven fabric was inferior in water absorbency.

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EFFECTS OF THE INVENTION According to the present invention, the spun yarn is excellent in cooling property, spinnability and stretchability, has good biodegradability and can be controlled, and is rich in hygroscopicity and water absorption. Further, it is possible to provide a laminated non-woven fabric having a sufficient strength to withstand actual use and a method for producing the same.

The laminated nonwoven fabric of the present invention is used as a material for medical and hygiene materials such as diapers and sanitary products, wipes such as disposable hand towels and wiping cloths, disposable packaging materials, bags for collecting garbage for household and business use, and other waste materials. It is suitable as a material for daily life such as a processing material, or an industrial material typified by agriculture, gardening, and civil engineering. Moreover, since this laminated non-woven fabric is biodegradable, it decomposes and disappears completely after use, which is beneficial from the viewpoint of protecting the natural environment, or it can be reused by, for example, composting it into a fertilizer. It is also useful from the perspective of resource reuse.

Claims (6)

[Claims] 1. A short fiber web made of composite short fibers and a natural fiber web made of natural fibers are laminated and integrated by partial ultrasonic fusion, and the composite short fibers are biodegradable. 1. A core-sheath composite cross section formed from a core component composed of an aliphatic polyester of 1 and a sheath component composed of a second aliphatic polyester having a biodegradability having a lower melting point than that of the core component. Characteristic laminated non-woven fabric. 2. The laminated nonwoven fabric according to claim 1, wherein the natural fiber is a cotton fiber, a ramie fiber, or a silk fiber cut into a short fiber shape. 3. The core component is polybutylene succinate, and the sheath component is copolymerized with ethylene succinate or butylene adipate in butylene succinate so that the copolymerization ratio of butylene succinate is 70 to 90 mol%. The laminated nonwoven fabric according to claim 1 or 2, which is a copolymerized polyester that is polymerized. 4. A single yarn fineness composed of a core component and a sheath component is 1.5 to 10 denier, and a composite ratio of the core component / the sheath component is 1/3 to 3/1 (weight ratio). The laminated nonwoven fabric according to any one of claims 1 to 3, characterized in that. 5. The laminate according to any one of claims 1 to 4, wherein a lamination ratio of the natural fiber web and the short fiber web is 10/90 to 90/10 (% by weight). Non-woven fabric. 6. A core comprising a core component made of a first aliphatic polyester having biodegradability and a sheath component made of a second aliphatic polyester having a biodegradability having a melting point lower than that of the core component. Melt composite spinning of sheath-type composite fibers is followed by drawing, and the resulting drawn yarn is mechanically crimped and then cut into predetermined lengths to form short fibers, and the short fibers are carded to obtain short fibers. Forming a web, after laminating a natural fiber web made of natural fibers to this short fiber web, ultrasonic fusion treatment is applied to both webs to partially fuse and unify the laminated nonwoven fabric. Production method.