JPH09279450A - 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, rich in both moisture and water absorbability, and having enough mechanical strength to stand its practical use. SOLUTION: This laminated nonwoven fabric has such structure that a short fiber web comprising conjugate short fibers is laminated with a natural fiber web comprising natural fibers and the laminate is integrated through three- dimensional interlacing. Each of the conjugate short fibers is made up of high- melting component A consisting of a 1st biodegradable aliphatic polyester and low-melting component B consisting of a 2nd biodegradable aliphatic polyester lower in melting point than the 1st polyester, and has such structure that the respective plural high-melting components A and low-melting components B are alternately laminated with each other in the fiber cross-section and lie continuous in the direction of fiber axis and also exposed onto the fiber surface.

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.

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 and has excellent cooling properties, spinnability and stretchability of spun yarn, good biodegradability, and hygroscopicity. The present invention is intended to provide a laminated nonwoven fabric which is rich in 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 three-dimensional entanglement, and the composite short fibers are a first fat having biodegradability. A composite short fiber composed of a high melting point component made of a group polyester and a low melting point component made of a second aliphatic polyester having a biodegradability having a melting point lower than that of the high melting point component. A plurality of high-melting point components and low-melting point components are alternately laminated in the fiber cross section, and the high-melting point component and the low-melting point component are continuous in the fiber axis direction and are exposed on the fiber surface. Non-woven fabric.

(2) A high-melting-point component composed of a first aliphatic polyester having biodegradability and a low-melting-point component composed of a second aliphatic polyester having a lower melting point than the high-melting-point component. By using a multi-layer composite fiber in which a plurality of high-melting point components and low-melting point components are alternately laminated in the fiber cross-section, and the high-melting point component and the low-melting point component are continuous in the fiber axis direction and are exposed on the fiber surface. Melt-spinning, then the spun yarn is drawn, the resulting drawn yarn is mechanically crimped, and then cut into short fibers to give short fibers. It is characterized in that a fibrous web is formed, a natural fiber web made of natural fibers is laminated on the short fibrous web, and then a pressurized liquid flow treatment is performed to three-dimensionally entangle and integrate the constituent fibers of both webs. Method for producing a layer nonwoven fabric.

As described above, since the short fiber web constituting the laminated nonwoven fabric of the present invention is formed of the multi-layer composite short fiber 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 three-dimensional entanglement, it is excellent in peeling strength between both webs and can sufficiently endure practical use. is there.

[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 high-melting point component made of a first aliphatic polyester having biodegradability and a second high-melting point component having a lower melting point than the high-melting point component.
Is a composite short fiber formed from a low melting point component composed of the aliphatic polyester.

As the first and second biodegradable aliphatic polyesters constituting the high melting point component and the low melting point component,
For example, poly (α) such as polyglycolic acid and polylactic acid
-Hydroxy acids) or copolymers composed of repeating unit elements constituting them. In addition, poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone) and poly (β-propiolactone) further includes
Poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaproate, poly-3-hydroxyheptanoate, poly-3-
Poly (β-hydroxyalkanoates) such as hydroxyoctanoate, and the repeating unit elements constituting them, and poly-3-hydroxyvalerate and poly-4-
A copolymer with a repeating unit element constituting hydroxybutyrate is exemplified. Further, as the one consisting of a condensation polymer of a diol and a dicarboxylic acid, for example, polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene acetate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, polybutylene sebacate , Polyhexamethylene sebacate, polyneopentyl oxalate, or copolymers composed of repeating units constituting these. Further, a plurality of these aliphatic polyesters can be blended and used. Among the above aliphatic polyesters, polybutylene succinate, polyethylene succinate and polybutylene adipate are particularly preferred from the viewpoints of spinnability and biodegradability.
More particularly, a copolymerized polyester obtained by copolymerizing ethylene succinate or butylene adipate with butylene succinate as a main repeating unit is preferable. In the present invention, of the two types of polymers selected from the above aliphatic polyesters, the polymer having a higher melting point is a high melting point component, and the polymer having a lower melting point is a low melting point component. .

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

According to the present invention, as will be described later, in the cross section of the fiber, the biodegradability is inferior, but the cooling property and the spinnability,
Along with subdividing the high-melting-point component with excellent stretchability, the low-melting-point component, which is inferior in the cooling and spinnability and stretchability of the spun yarn but has excellent biodegradability, is subdivided. By alternately laminating in the fiber cross section,
It is possible to obtain a nonwoven fabric excellent in all of the cooling property and spinnability, stretchability and biodegradability of the spun yarn.

Therefore, in the present invention, the difference in melting point between the high melting point component and the low melting point component is preferably 5 ° C. or more, more preferably 10 ° C. or more. If the melting point difference between the high-melting point component and the low-melting point component is less than 5 ° C., the fiber cross-section approaches a full-melt type as in the case of a single phase. The effect of the present invention that the cooling property, spinnability, stretchability and biodegradability are satisfied cannot be exhibited.

Therefore, polybutylene succinate is used as the high melting point component, and ethylene succinate or butylene succinate is added to the butylene succinate so that the copolymerization ratio of the butylene succinate is 70 to 90 mol% as the low melting point component. It is preferable to use a copolymerized polyester obtained by copolymerizing butylene adipate. If the copolymerization 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 desired short fiber can be obtained. It will not be. Conversely, if it exceeds 90 mol%, the spun yarn has excellent cooling properties, spinnability and stretchability, but 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 high melting point component and the low melting point component is
The number average molecular weight is about 20,000 or more, preferably 40,
Those having a molecular weight of 000 or more, more preferably 60,000 or more are good in terms of the spinning properties and the properties 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.

Further, in the present invention, if necessary, for example, a matting agent, a pigment, a light stabilizer and an antioxidant may be added to either or both of the above-mentioned high melting point component and low melting point component. It can be added within a range that does not impair the effect.

In particular, in the short fiber applied in the present invention, it is preferable that the crystal nucleating agent is added to at least the low melting point 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 not particularly limited as long as it is a powdery inorganic substance and does not dissolve in the melt, but talc, calcium carbonate, titanium oxide, boron nitride, silica gel, Magnesium oxide or the like is usually used, and among these, talc, titanium oxide, or a mixture thereof is preferably used.

Regarding the crystal nucleating agent, the amount of the crystal nucleating agent added to the high melting point component was QA (wt%), and the amount of the crystal nucleating agent added to the low melting point component was QB (wt%). sometimes,
It is preferable that it is added so as to satisfy the formulas (1) and (2). [(ΔTA + ΔTB) / 100] −2 / 3 ≦ QA + QB ≦ [(ΔTA + ΔTB) / 100] +4 (1) QA ≦ QB (2) where ΔTA = melting point of high melting point component−high melting point component Crystallization temperature ≧ 35 ΔTB = melting point of low melting point component−crystallization temperature of low melting point component ≧
If the total amount of the crystal nucleating agent QA + QB (% by weight) exceeds the upper limit defined by the formula (1), the spun yarn has a high cooling effect, but the spinnability is reduced and the obtained short fibers are obtained. As a result, the mechanical performance of the nonwoven fabric is inferior, which is not preferable. Conversely, if the total amount of the crystal nucleating agent QA + QB (% by weight) is lower than the lower limit defined by the formula (1), the cooling property of the spun yarn is reduced, and adhesion between the spun yarns occurs. Then, it becomes difficult to obtain the target nonwoven fabric. Also, when the addition amount QA (% by weight) of the nucleating agent in the high melting point component is larger than the addition amount QB (% by weight) of the nucleating agent in the low melting point component, the cooling property of the high melting point component is reduced. Although it is further improved, the cooling property of the low-melting point component is lowered, and this is not preferable because adhesion between spun yarns is likely to occur.

In the equation (1), ΔT is the difference between the melting point of each component and the crystallization temperature, but in the spinning process, the smaller ΔT, the better the cooling property of the spun yarn. In the polymer of the present invention, ΔT is usually as large as 35 or more. However, the cooling of the spun yarn can be effectively promoted by adding a nucleating agent.

In the present invention, the viscosities of the high melting point component and the low melting point component are not particularly limited, but the viscosity of the high melting point component is preferably lower than the viscosity of the low melting point component. this is,
Generally, in composite spinning of a thermoplastic resin, this is because a low-viscosity component acts to cover a high-viscosity component. That is, in the present invention, by lowering the viscosity of the high melting point component having a high degree of crystallinity, which is inferior in biodegradability, the exposure ratio of the low melting point component segment on the fiber surface is reduced, and the spun yarn is removed. Adhesion can be prevented and spinnability and stretchability can be improved. However, if the viscosity is too low, the high melting point component will cover most of the low melting point component segment, so that the adhesion can be improved but the biodegradation performance is inferior, and the object of the present invention. Not something.

Therefore, the melt flow rate value (hereinafter referred to as MFR value) of the polymer applied in the present invention is such that the high melting point component is 20 to 70 g / 10 minutes and the low melting point component is 15 to 70 g / 10 min.
It is preferably 50 g / 10 minutes. However, the MFR value in the present invention is measured according to the method described in ASTM-D-1238 (E). MF of high melting point component
When the R value is less than 20 g / 10 min and / or the MFR value of the low melting point component is less than 15 g / 10 min, the spun yarn is not smoothened smoothly because the viscosity is too high, resulting in poor operability. As a result, the resulting fibers have a large fineness and poor uniformity. Conversely, MF of high melting point component
MF with R value of 70 g / 10 min and / or low melting point component
If the R value exceeds 50 g / 10 minutes, the viscosity is so low that not only the composite cross section becomes unstable, but also yarn breakage occurs in the spinning process, impairing operability and mechanical properties of the obtained nonwoven fabric. Is inferior. For these reasons, the MFR value of the high melting point component is 25 to 65 g / 10
More preferably, the MFR value of the low melting point component is 18 to 45 g / 10 minutes.

Next, the fiber cross-sectional shape of the composite short fiber applied to the present invention will be described. In the multilayer composite cross section of the present invention, a plurality of high melting point components and low melting point components are alternately laminated in the fiber cross section, and the high melting point component and the low melting point component are continuous in the axial direction of the fiber and on the fiber surface. It needs to be exposed. By laminating a plurality of high-melting-point components and low-melting-point components, for example, even if the low-melting-point component is a polymer inferior in cooling, spinnability and stretchability, it is spun by an adjacent high-melting-point component. It is possible to improve the cooling property, spinnability and stretchability of the spun yarn. In addition, even if the high melting point component is a polymer with poor biodegradability, the biodegradability of the adjacent low melting point component is excellent, so if the low melting point component decomposes over time, the high melting point component is left as a flake with very small fineness. This results in excellent biodegradability as a nonwoven fabric. Further, it is necessary that both the high melting point component and the low melting point component are continuous in the fiber axis direction in order to enhance the stability of the fiber cross section, the spinning property, and the mechanical properties of the fiber. In addition, it is necessary that both of the two components are exposed on the fiber surface in order to improve the cooling property, spinnability and stretchability of the spun yarn and to promote and control the biodegradability.

In the fiber cross section of the composite staple fiber applied to the present invention, the total number of laminated layers of the high melting point component and the low melting point component is 4 or more, and the single yarn fineness of the composite staple fiber is 1.5 to.
It must be 10 denier. If the total number of layers is less than 4, the spun yarn is inferior in cooling property, spinnability, stretchability and decomposition performance. That is, in the multilayer cross section of the present invention, the larger the individual layers are, the poorer the cooling properties, spinnability, stretchability and decomposition performance of the spun yarn are. In addition, the total number of layers needs to be controlled based on the fineness of the conjugate short fibers. That is, 1.5
In the case of a fineness such as d (denier), if the total number of laminated layers is too large, not only the cross-sectional shape becomes unstable during the yarn making process but also yarn breakage easily occurs, which is not preferable. On the other hand, in the case of a large fineness such as 10d, if the total number of laminated layers is too small, the spun yarn has poor cooling properties and drawability,
Further, since the size of each component is large, the decomposition performance is inferior. For this reason, the total number of stacked layers is 4 to
More preferably, it is 16. The size of the laminated pieces may be individually different. Further, when the single yarn fineness of the composite short fibers is less than 1.5d, the resin flow in the spinneret becomes unstable, the yarn breakage occurs frequently in the spinning process, the production amount decreases, and the fiber cross-sectional shape becomes unstable. It is not preferable because it occurs. On the other hand, if it exceeds 10 d, the spun yarn is inferior in the cooling property and in the decomposition performance. For this reason, it is more preferable that the single yarn fineness is 2d to 8d.

The composite fiber applied to the present invention preferably has a high melting point component / low melting point component composite ratio of 1/3 to 3/1 (weight ratio). If the compounding ratio is out of this range, the cooling properties, spinnability, stretchability, and biodegradability of the spun yarn cannot all be satisfied, and further, instability of the fiber cross-sectional shape is induced. Is not preferred. For example, when the composite ratio of the high-melting-point component / low-melting-point component exceeds 1/3, the resulting biodegradability is excellent, but the cooling property and the opening property of the spun yarn are poor. Conversely, when the composite ratio of the high melting point component / the low melting point component exceeds 3/1, the spun yarn is excellent in the cooling property and the spreadability, but is inferior in the biodegradability. Further, for example, if the high melting point component is a polymer having poor biodegradability, the biodegradation rate can be promoted by increasing the composite ratio of the low melting point component. For this reason, the ratio is more preferably 1/2 to 2/1 (weight ratio).

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.

When using the fluff, the fluff machine that can be effectively used is a rag machine, a knot breaker, a garnet machine, a turning machine and the like. The type and combination of the anti-fluffing machines used depend on the shape of the fabric to be fluffed, the thickness of the yarns constituting it, and the twisting strength, but it is also possible to connect multiple identical anti-fluffing machines in series, It is effective to use a combination of more than one kind of anti-fluffing machine. The defibration rate by the fluffing machine is preferably in the range of 30 to 95%. When the defibration rate is less than 30%, undefibrated fibers are present in the card web, and the surface of the nonwoven fabric becomes rough, which is not preferable. In addition,
The defibration rate is obtained by the formula shown below.

Disentanglement ratio (%) = (weight of woven fabric-weight of filamentous material) / weight of woven fabric × 100 The short fiber web and the natural fiber web in the present invention are
It may be a parallel web arranged in the traveling direction of the card machine, a cross-laid web of parallel webs, a randomly arranged random web, or a semi-random web arranged in a medium size, which should be appropriately selected depending on the intended use. You can 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 three-dimensional entanglement. That is, the constituent liquid of the short fiber web and the constituent fiber of the natural fiber web are three-dimensionally entangled with each other and integrated by performing the pressurized liquid flow treatment described later. As a result, the short fiber web and the natural fiber having no heat-adhesiveness can be integrated with each other with sufficient strength 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, first, the above-mentioned biodegradable aliphatic polyester, that is, polybutylene succinate as a high melting point component and butylene succinate as a low melting point component have a copolymerization ratio of 70 to 90 mol%.
Copolymerized polyester having butylene succinate as the main repeating unit is melted separately so that the composite ratio of high melting point component / low melting point component becomes 1/3 to 3/1 (weight ratio) After being individually weighed, the spun yarn is discharged from a composite spinneret capable of forming a multilayer fiber cross-sectional structure satisfying the number of segments of both components and the single yarn fineness described above.

A schematic view of a spinneret for obtaining such a multilayer composite fiber is shown in FIG. Here, 1 is an intermediate plate, which is an introduction hole 2 for a high melting point component and an introduction hole 3 for a low melting point component.
And 4 is a mouthpiece, and the mouthpiece 4 is an introduction hole 2, 3
The high-melting-point component and the low-melting-point component that have been ejected are combined at the site 5 and bonded together to form a composite flow. Then, the composite flow bonded together is the static type kneading element 6
Is introduced into the guide hole 7 in which is provided and is spun out from the discharge hole 8 as a multilayer composite flow. The number of layers in the fiber cross section of the obtained conjugate fiber is determined by the number of stationary kneading elements 6. In addition, the spinneret for obtaining the multilayer composite fiber is
It is not limited to such a configuration.

2, 3, and 4 illustrate the cross-sectional structure of the multi-layer type composite fiber according to the present invention. Where A
Indicates a high melting point component, and B indicates a low melting point component.

The spun fiber is cooled by a known cooling device. Then, the undrawn yarn is wound up by a take-up roll at a speed of 800 to 2500 m / min, and the 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, when stretching is performed with a large fineness, it is necessary to increase the number of stretching rolls and further perform thermal stretching. Then, the obtained drawn yarn is crimped by a stuffer box and then cut into a predetermined length to obtain short fibers. The above is a two-step method, but it is also possible to obtain short fibers by a one-step method, that is, a so-called spin draw method in which an 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, the obtained short fiber web is laminated with a natural fiber separately prepared by a conventional method, and a pressurized liquid flow treatment is applied thereto to form a three-dimensional entanglement between the constituent fibers to integrate them to form a laminated nonwoven fabric. obtain.

When performing the pressurized liquid flow treatment, as the injection holes of the pressurized liquid flow, orifices having a diameter of 0.05 to 1.5 mm are arranged in one row or a plurality of rows at 0.4 to 5 mm intervals. It is preferable to use a head and arrange the orifice heads in 3 to 10 stages. The orifice head may be arranged on one side or both sides of the laminated web.

In the pressurized liquid flow process, the first hydraulic pressure is set to 45.
After pre-entanglement with a pressurized liquid flow of less than kg / cm ² G, then 45 kg / cm as the second and subsequent treatments.
^It is performed by performing an entanglement treatment with a pressurized liquid flow having a hydraulic pressure of ² G or more. When the first hydraulic pressure is 45 kg / cm ² G or more, the turbulence of the web occurs due to the accompanying airflow generated by the pressurized liquid flow, and the short fibers constituting the web are generated by the pressurized liquid flow. It is not preferable in terms of keeping the quality of the laminated non-woven fabric which is dropped and becomes a product. The laminated non-woven fabric obtained by the above method is inverted, and the third confounding treatment is performed with the hydraulic pressure applied for the second time to obtain a laminated non-woven fabric on both front and back sides.

In the treatment of the pressurized liquid flow, the porous support plate on which the laminated web is placed is made of metal or polyester as long as the pressurized liquid flow passes through the laminated web placed on the support plate. , Any of the other materials may be used.
The range of the mesh of the porous support plate is appropriately selected depending on the application, but it is preferable to use the mesh of 20 to 150 mesh. If it is less than 20 mesh, the resulting laminated nonwoven fabric is substantially perforated, and when it is used for the purpose of, for example, putting in household waste or commercial waste, fine scraps flow out from the perforated portion, which is not preferable. On the other hand, when it exceeds 150 mesh, it is necessary to increase the liquid pressure of the liquid flow passing through the laminated web and the net, which is not preferable in terms of production cost. For the above reasons, the range of the mesh of the porous support plate is more preferably 30 to 100 mesh.

The laminated nonwoven fabric obtained by the above method is
Excess water is removed by mangle which is a known water removing device and then dried.

[0046]

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 (MFR) value (g /
10 minutes); measured at a temperature of 190 ° C. according to the method described in ASTM-D-1238 (E).

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 sample weight of 5 mg and heating rate of 20 ° C./min. Was given as the melting point (° C.). Crystallization temperature (° C.); using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., a sample weight of 5 mg and a temperature decreasing rate of 20 ° C./min. The temperature was taken as the crystallization temperature (° C).

Coolability: The spun yarn was visually observed 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; ◯: 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 state sample and made into equilibrium moisture, and then 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); JIS-L-10
It was measured according to the method described in 96A. That is, 10 sample pieces having a sample length of 20 cm and a sample width of 5 cm were prepared, and a constant-speed extension type tensile tester (Tensilon UTM manufactured by Toyo Baldwin Co., Ltd.) was used for each sample piece in the longitudinal direction of the nonwoven fabric.
-4-1-100) was used to stretch at a pulling speed of 10 cm / min, and the average value of the load values at cutting obtained was determined to be strong (kg
/ 5 cm width).・ Biodegradability: When the nonwoven fabric is buried in the soil and taken out after 6 months, and the nonwoven fabric does not retain its shape, or even if it retains its shape, the strength is relative to the initial strength before embedding. If it is reduced to 50% or less, the biodegradability is good (○), and if the strength exceeds 50% of the initial strength before burying, the biodegradability is poor (;
X). Water absorption (mm): Measured according to the Bayrec method described in JIS-L-1096. That is, the sample length is 20c
m, 5 sample width 2.5cm sample pieces were created, and each sample piece was hung by a pin on a horizontal bar supported at a certain height above the water tank containing 20 ± 2 ° C water. Align the lower end of the sample piece in a line and lower the horizontal bar so that 1 cm of the lower end of the sample piece is just submerged in water, measure the height (mm) of water rise after leaving for 10 minutes, and absorb the average value. (Mm).

Example 1 As a high melting point component, the MFR value was 30 g / 10 min and the melting point was 1
Polybutylene succinate resin having a melting point of 102 ° C. and crystallization temperature of 52 ° C. and polybutylene succinate / ethylene succinate = 85 / A non-woven fabric composed of multi-layered composite short fibers was produced using 15 mol% of the copolymer resin.

That is, the above-mentioned two components are melted at a temperature of 180 ° C. by using an individual extruder type melt extruder, and a fiber spinning cross section (round shape, total number of laminated layers 8) as shown in FIG. 2 is formed. Single hole discharge rate = 1.02 g /
The multilayer composite fiber was melt-spun under the condition of composite ratio (high melting point component / low melting point component) = 1/1 (weight ratio). After cooling this spun yarn with a cooling device, it was taken up with a winding roll at a winding speed of 1000 m / min,
The unstretched yarn having a single yarn fineness of 9.2 denier (d) was wound up. A plurality of these undrawn yarns are aligned and drawn with a known drawing machine at a draw ratio of 3.2 times, crimped with a stuffer box, and then cut into 51 mm to make a brand 3d x 51 mm. The short fiber of was obtained.

Then, the obtained short fibers are put into a parallel card.
It is supplied to the machine and the basis weight is 25 g / m ^TwoCard web of
Got ready. On the other hand, as a non-woven fabric made of natural fibers, cotton
Using bleached cotton, the basis weight is 25 with a random card machine.
g / m^TwoPrepared a card web.

Then, a web layer made of multilayer composite short fibers and a web layer made of bleached cotton were laminated at a lamination ratio of 50/50.
(Wt%) and then placed on a moving wire mesh of 50 mesh, and as a high pressure liquid flow injection hole from a position 50 mm above the laminated nonwoven web layer, a hole diameter of 0.12 mm and a hole interval of 0. A device with orifice heads arranged in a line at 6 mm arranged in 5 stages was used.
After the pre-entanglement was performed with the high-pressure liquid flow of g / cm ² , the entanglement process was performed with the high-pressure liquid flow of the liquid pressure of 85 kg / cm ² after the second time. Further, after removing excess water of the obtained laminated nonwoven fabric with mangle, a drying treatment was carried out by a dryer kept at a temperature of 80 ° C. As a result, a laminated nonwoven fabric having a basis weight of 50 g / m ² was obtained.

Table 1 shows the yarn-forming operability of the multi-layered composite short fibers and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

[0060]

[Table 1]

Example 2 Melt spinning was performed at a single hole discharge rate of 0.51 g / min, a composite ratio (high melting point component / low melting point component) = 1/3 (weight ratio), and a single yarn fineness of 4.6 d. An undrawn yarn was obtained. The undrawn yarn was drawn at a draw ratio of 2.4 and cut at a cut length of 38 mm. Then, otherwise, under the same conditions as in Example 1,
A multilayer composite short fiber was produced. The brand of the obtained short fiber was 2d × 38 mm. Next, 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, the same basis weight as in Example 1 is 25
A bleached cotton card web of g / m ² cotton was prepared.

A web layer made of these multi-layered composite short fibers and a web layer made of bleached cotton were laminated at a ratio of 50 /
It was laminated at 50 (wt%) and further integrated by a high pressure liquid flow to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ² . The processing conditions for the high pressure liquid flow were the same as in Example 1. Table 1 shows the yarn-forming operability of the multi-layered composite short fiber and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

Example 3 Single hole discharge rate = 2.20 g / min, composite ratio (high melting point component / low melting point component) = 3/1 (weight ratio), and winding speed 800
Take-up melt spinning at m / min and single yarn fineness of 24.8
An undrawn yarn of d was obtained. In addition, the film is drawn at a draw ratio of 4.3,
The cut length was 96 mm. Other than that, Example 1
Under the same conditions as above, a multi-layer type composite short fiber was produced. The brand of the obtained short fibers was 6d × 96 mm. Then
This short fiber is fed to a parallel card machine and the basis weight is 25
A card web of g / m ² was prepared. Further, a bleached cotton card web of 25 g / m ² cotton having the same basis weight as in Example 1 was prepared.

Then, a web layer made of these multi-layered composite short fibers and a web layer made of bleached cotton were laminated at a lamination ratio of 50 /.
Layered at 50 (wt%), integrated by high pressure liquid flow,
A laminated nonwoven fabric having a basis weight of 50 g / m ² was obtained. The processing conditions for the high pressure liquid flow were the same as in Example 1. Table 1 shows the yarn-forming operability of the multi-layered composite short fiber and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

Example 4 Using the same high melting point component and low melting point component as in Example 1, and using a spinneret having a fiber cross section (trilobal shape, total number of laminated layers 8) as shown in FIG. The multilayer composite fiber was melt-spun under the conditions of discharge amount = 0.96 g / min and composite ratio (high melting point component / low melting point component) = 1/1 (weight ratio). This spun yarn was cooled by a cooling device and then wound up under the same conditions as in Example 1 to obtain an undrawn yarn having a single yarn fineness of 8.6d. A plurality of yarn bundles of this undrawn yarn are bundled and drawn at room temperature with a draw ratio of 3
And then crimped and cut into 51 mm to obtain short fibers of brand 3d × 51 mm.

This short fiber was supplied to a parallel card machine to prepare a card web having a basis weight of 25 g / m ² .
A card web having a basis weight of 25 g / m ² was prepared using the same bleached cotton as in Example 1.

A web layer made of these multi-layered composite short fibers and a web layer made of bleached cotton were laminated at a ratio of 50 /
Layered at 50 (wt%), integrated by high pressure liquid flow,
A laminated nonwoven fabric having a basis weight of 50 g / m ² was obtained. The processing conditions for the high pressure liquid flow were the same as in Example 1. Table 1 shows the yarn-forming operability of the multi-layered composite short fiber and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

Example 5 The basis weight of the same multi-layer composite short fibers as in Example 1 was 1
The short fiber web layer of 0 g / m ^{2 and} the web layer of bleached cotton having a basis weight of 40 g / m ² are laminated in a ratio of short fiber web layer / exposed cotton web layer = 20/80 (wt%). So that they are laminated together by a high-pressure liquid flow, and the basis weight is 5
A laminated nonwoven fabric of 0 g / m ² was obtained. The processing conditions for the high pressure liquid flow were the same as in Example 1. At this time, the yarn-forming operability of the multi-layer type composite short fiber, the physical properties of the laminated non-woven fabric and the decomposition performance,
It is shown in Table 1. Example 6 The unit weight of the same multi-layered composite short fibers as in Example 1 was 4
The short fiber web layer of 0 g / m ^{2 and} the web layer of bleached cotton having a basis weight of 10 g / m ² are laminated in a ratio of short fiber web layer / exposed cotton web layer = 80/20 (wt%). So that they are stacked together and integrated by a high-pressure liquid flow to give a basis weight of 5
A laminated nonwoven fabric of 0 g / m ² was obtained. The processing conditions for the high pressure liquid flow were the same as in Example 1. At this time, the yarn-forming operability of the multi-layer type composite short fiber, the physical properties of the laminated non-woven fabric and the decomposition performance,
It is shown in Table 1.

Example 7 A short fiber composed of alternately laminated composite fibers was prepared in the same manner as in Example 1 except that a crystal nucleating agent was added to the high melting point component and the low melting point component and the draw ratio was 3.1 times. A fibrous nonwoven fabric was produced. That is, a masterbatch containing 20% by weight of talc / titanium oxide = 1/1 (weight ratio) having an average particle size of 1.0 μm as a crystal nucleating agent is used as a high melting point component polymer and low melting point component polymer base. Created in advance,
The masterbatch and the corresponding polymer are blended, and the nucleating agent to be added to the high melting point component is 0.1%.
The raw material was prepared such that the nucleating agent added to the low melting point component was 2% by weight and the nucleating agent was 1.0% by weight. Table 1 shows the spinning operability, physical properties and biodegradability of the obtained nonwoven fabric at this time.

[0070] and a web layer in which the same basis weight as Comparative Example 1 Example 1 is a multilayer composite short fibers and a basis weight of 25 g / m ² is formed of bleached cotton 25 g / m ² by laminating a ratio 50/50 (wt%) The layers were laminated and heat-bonded by 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 engraved portions having an engraved area of 0.6 mm ² was used as the engraved roll, and the pressing area ratio of the embossed portions was 15%, and the linear pressure was 50 kg / cm. The temperature was 90 ° C. Table 2 shows the yarn-forming operability of the multi-layered composite short fibers and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

[0071]

[Table 2]

Comparative Example 2 The same high-melting point component and low-melting point component as in Example 1 were used, and a spinneret with a fiber cross section of a core-sheath type was used. Hole discharge rate = 1.15 g /
The core-sheath type composite fiber was melt-spun under the condition of composite ratio (high melting point component / low melting point component) = 1/1 (weight ratio). That is, the high-melting point component and the low-melting point component are melted at a temperature of 180 ° C. by using individual extruder type melt extruders, cooled by a cooling device, and then an oil agent is applied thereto, and a winding roll having a take-up speed of 1000 m / min. Fineness through 10.3
A denier undrawn yarn was obtained. Then, a plurality of the undrawn yarn bundles were bundled and drawn at room temperature at a draw ratio of 3.6. Table 2 shows the yarn operability of the multi-layered composite short fiber at this time.

Comparative Example 3 The same high melting point component as in Example 1 was used, and a spinneret in which the cross-section of the fiber was a single phase type was used. Single phase type under the condition of single hole discharge rate = 1.2 g / min. The fibers were melt spun. That is, the high melting point is heated to a temperature of 1 using an extruder melt extruder.
After melt-spun at 80 ° C., cooled by a cooling device, an oil agent was applied, and an undrawn yarn having a fineness of 10.8 denier was obtained through a winding roll having a take-up speed of 1000 m / min.

Next, a plurality of yarn bundles made of this undrawn yarn were bundled and drawn at room temperature at a draw ratio of 3.8. Next, apply 14 crimps / inch in the staff box,
After that, it was cut into 51 mm to obtain short fibers of brand 3d × 51 mm. Further, this short fiber was supplied to a parallel card machine to prepare a card web having a basis weight of 25 g / m ² .

The same basis weight as in Example 1 was 25 g / m 2.
A bleached cotton card web of ² cotton was prepared. Then, a web layer made of the above-mentioned single-phase short fibers and a web layer made of bleached cotton are laminated at a lamination ratio of 50/50 (wt%), integrated by a high pressure liquid flow, and laminated with a basis weight of 50 g / m ² . A non-woven fabric was obtained. The processing conditions with the high-pressure liquid flow were the same as in Example 1.

Table 2 shows the yarn-forming operability of the multi-layered composite short fiber and the physical properties and decomposition performance of the laminated nonwoven fabric at this time.

In the above, Example 1 is a laminated non-woven fabric of the multi-layer composite short fiber of the present invention and a natural fiber, and this multi-layer composite short fiber had good cooling properties, spinnability and stretchability. In addition, since the multi-layered composite short fibers and natural fibers are laminated by high-pressure liquid flow processing, the bonding strength between the two layers is 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, the proportion of the low-melting point component was large, but the fineness was small and the multi-layer type composite short fiber was applied. Therefore, like Example 1, the cooling property of the multi-layer type composite fiber, The spinnability and stretchability were good. Further, this laminated nonwoven fabric was also excellent in mechanical performance and water absorption.
The decomposition performance of this laminated non-woven fabric was better than that of the laminated non-woven fabric obtained in Example 1 due to the large proportion of low melting point components.

In Example 3, since the multi-layered composite continuous fiber having a high ratio of the high melting point component is applied, even if the fineness is increased, the cooling property of the multi-layered composite fiber is the same as in Example 1. The spinnability and stretchability were good. Further, this laminated nonwoven fabric was also excellent in mechanical performance, water absorption and biodegradability.

Since the cross-section of Example 4 was a multi-layer type composite fiber having a trilobal cross section, the composite fiber was excellent in cooling property, spinnability and drawability as in Example 1, and the mechanical performance of the laminated non-woven fabric. The water absorbency and the decomposition performance were also good.

In Example 5, both webs similar to those in Example 1 were used and the lamination ratio was made rich in natural fibers.
Although the mechanical performance was slightly inferior to that of Example 1, the water absorption and biodegradability were even better than those of Example 1.

In Example 6, both webs similar to those in Example 1 were used, and the lamination ratio was set to the multilayer type composite fiber rich. Therefore, the water absorption property was slightly inferior to that in Example 1, but the mechanical performance and biodegradability were low. Even better results than in Example 1 were obtained.

In Example 7, since the crystal nucleating agent was contained in the polymer, the spinnability of the spun yarn was better than that of Example 1. Further, this nonwoven fabric was also excellent in mechanical performance and decomposition performance.

On the other hand, in Comparative Example 1, the web obtained in Example 1 was treated with the embossing roll as the heat-sealing device, which is outside the scope of the present invention, so the adhesive force between the two layers was weak, It was not able to withstand use at all.

In Comparative Example 2, the same high-melting point and low-melting point components as in Example 1 were used, but the fiber cross-section was a core-sheath type outside the scope of the present invention, and the low-melting point component had a fiber cross-section. Since the entire circumference was covered, the spun yarn was in close contact in the spinning process, and many yarn breakages occurred in the drawing process, so that the desired short fiber could not be obtained.

In Comparative Example 3, although the same high melting point component as in Example 1 was used, since the fiber cross-section was a single-phase type which was outside the scope of the present invention, the mechanical performance of the nonwoven fabric was excellent. However, the biodegradability was inferior. That is, when the obtained non-woven fabric was buried in soil for 6 months, and then excavated and observed, the non-woven fabric form was maintained, and the non-woven fabric strength was 91% before embedding, and the biodegradability was extremely poor. Met.

[0087]

INDUSTRIAL APPLICABILITY The present invention has excellent cooling properties, spinnability and stretchability during spinning of multi-layered composite fibers having biodegradability, and a high pressure liquid as a method for laminating a multi-layered composite fiber web and a natural fiber web. Since the flow processing is applied, it is possible to obtain a biodegradable laminated non-woven fabric which is excellent in peeling strength between two layers in the laminated non-woven fabric and further excellent in mechanical performance and water absorption performance.
Further, it is a manufacturing method suitable for obtaining the laminated nonwoven fabric.

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

[Brief description of drawings]

FIG. 1 is a schematic view of an example of a spinneret for obtaining a multi-layer composite fiber according to the present invention.

FIG. 2 is a schematic view of a fiber cross section of an example of a multi-layer type composite fiber according to the present invention.

FIG. 3 is a schematic view of a fiber cross section of another example of the multilayer conjugate fiber according to the present invention.

FIG. 4 is a schematic view of a fiber cross section of still another example of the multilayer conjugate fiber according to the present invention.

[Explanation of symbols]

 A High melting point component B Low melting point component

Claims (9)

[Claims] 1. A first aliphatic having biodegradability, wherein a short fiber web made of composite staple fibers and a natural fiber web made of natural fibers are laminated and integrated by three-dimensional entanglement. The multi-layered composite short fiber is composed of a high-melting point component made of polyester and a low-melting point component made of a second aliphatic polyester having a lower melting point than the high-melting point component and having biodegradability. Fiber is
A plurality of high-melting point components and low-melting point components are alternately laminated in the fiber cross section, and the high-melting point component and the low-melting point component are continuous in the fiber axis direction and are exposed on the fiber surface. Non-woven fabric. 2. The laminated non-woven fabric according to claim 1, wherein the natural fiber is any one of cotton, ramie, and silk fiber cut into short fibers. 3. The high melting point component is polybutylene succinate, and the low melting point component is a copolymerized polyester having butylene succinate as a main repeating unit and a copolymerization amount ratio of butylene succinate of 70 to 90 mol%. The laminated non-woven fabric according to claim 1 or 2, wherein 4. The laminated non-woven fabric according to claim 1, wherein the low melting point component is a copolyester obtained by copolymerizing butylene succinate with ethylene succinate or butylene adipate. . 5. The total number of laminated layers of the high melting point component and the low melting point component is 4 or more, and the single yarn fineness of the composite fiber is 1.5 to.
It is 10 denier, The laminated nonwoven fabric of any one of Claim 1 to 4 characterized by the above-mentioned. 6. The composite ratio of high melting point component / low melting point component is 1 /
2. The weight ratio is 3 to 3/1 (weight ratio).
The laminated nonwoven fabric according to any one of items 1 to 5. 7. The layered product according to claim 1, wherein a crystal nucleating agent is added to at least the low melting point component of the low melting point component and the high melting point component. Non-woven fabric. 8. The laminate according to claim 1, wherein the natural fiber web and the short fiber web have a lamination ratio of 10/90 to 90/10 (% by weight). Non-woven fabric. 9. A high melting point component comprising a biodegradable first aliphatic polyester and a low melting point component comprising a biodegradable second aliphatic polyester having a lower melting point than this high melting point component are used. A plurality of high-melting-point components and low-melting-point components are alternately laminated in the cross section of the fiber, and the high-melting-point component and the low-melting-point component are continuous in the axial direction of the fiber and the multilayer type composite fiber exposed on the fiber surface is melted Spinning, then drawing the spun yarn, applying mechanical crimp to the obtained drawn yarn, and then cutting it into short fibers to give short fibers. A web is formed, a natural fiber web made of natural fibers is laminated on the short fiber web, and then a pressurized liquid flow treatment is performed to three-dimensionally entangle and integrate the constituent fibers of both webs. Woven fabric manufacturing method.