JP3262430B2 - Method for producing biodegradable laminated nonwoven structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminated nonwoven fabric structure in which a thermoplastic synthetic long-fiber nonwoven layer and a natural fiber nonwoven layer are laminated, and has biodegradability and peel strength. Highly flexible, excellent in both water absorbency and hydrophobicity, and used in medical and sanitary materials, wiping cloths and packaging materials, or household or business-related materials such as bags for collecting fresh dust, or agriculture The present invention relates to a method for producing a laminated nonwoven structure suitable as each material for industrial materials represented by the above.

[0002]

2. Description of the Related Art Conventionally, nonwoven fabrics made of thermoplastic synthetic polymer fibers such as polyethylene, polypropylene, polyester, and polyamide have been known as materials for medical and hygiene materials, general living materials, or some industrial materials. .
Since these nonwoven fabrics are composed of the above-mentioned polymers which are chemically stable in the normal natural environment, they do not have self-degradability. Therefore, in disposable applications, they are treated by incineration or landfill. It is a fact. Incineration requires a great deal of cost and is a problem from the viewpoint of protection of nature and living environment, such as pollution caused by waste plastic. On the other hand, as for landfills, as described above, there is a problem that the material is kept in the original state for a long time in soil because the material is chemically stable under a normal natural environment. In order to solve these problems, it is conceivable to select a nonwoven fabric made of a biodegradable material. For example, viscose rayon short fiber nonwoven fabric obtained by dry method or solution immersion method, kipura rayon long fiber nonwoven fabric obtained by wet spunbond method, short fiber nonwoven fabric made of cellulosic fiber represented by cotton and hemp, etc. Polysaccharides such as chitin, proteins (polyamino acids) such as cut-tooth (expanded lines) or atelocollagen, poly-3-hydroxybutyrate, poly-3-hydroxyvalerate, and poly-3-hydroxy produced by microorganisms in nature. Nonwoven fabrics composed of natural chemical fibers such as microbial polyesters such as caprolate, and nonwoven fabrics composed of synthetic aliphatic polyesters such as polyglycolide and polylactide. However, the former nonwoven fabric made of various rayon fibers, cellulosic fibers or the above-mentioned natural synthetic fibers has biodegradability, but the mechanical strength of the constituent material itself of the nonwoven fabric itself is low and hydrophilic. There are various problems such as a remarkable decrease in mechanical strength when wet, poor flexibility, and lack of thermal adhesiveness because the material itself is non-thermoplastic. In addition, the latter nonwoven fabric made of synthetic aliphatic polyester fiber is biodegradable and has improved mechanical strength, but it is difficult to fineness it. It is difficult to apply, and it is necessary to rely on wet spinning in terms of polymer properties. Therefore, multiple stepwise steps are required to obtain a nonwoven fabric, and large-scale processing is required to reduce processing costs. There is a problem that a complicated device is required.

On the other hand, as a laminated nonwoven structure,
BACKGROUND ART A laminated nonwoven structure in which a thermoplastic synthetic fiber nonwoven layer and a natural fiber nonwoven layer are laminated is known. For example, Japanese Patent Publication No. 54-24506 discloses that a gas-permeable heat-sealing layer made of a thermoplastic synthetic fiber non-woven fabric and a gas-permeable non-heat-sealing layer made of natural fibers and the like are laminated, and a heat-sealing layer is formed on the non-heat-sealing layer. A laminated nonwoven structure having a structure in which a substance is interspersed and a fusion part of a heat-welding substance and a heat-welding layer penetrates from both surfaces of the non-heat-welding layer and the non-heat-welding layer is bonded and sandwiched. Proposed. However, although this laminated nonwoven structure has excellent water absorbability due to the laminated natural fibers, the thermoplastic synthetic fiber nonwoven fabric is not made of a biodegradable material, and as described above for disposable applications. Problems arise. In addition, this laminated nonwoven structure is manufactured by laminating a gas-permeable heat-sealing layer and a gas-permeable non-heat-welding layer when manufacturing the same, and by superposing a heat-sealing sheet layer for impregnation on the non-heat-sealing layer. Forming a structure in which a welded portion of the heat-weldable substance and the heat-weldable layer penetrates from both sides of the non-heat-weldable layer by ultrasonic welding to form a structure in which the non-heat-weldable layer is adhered and sandwiched; From the viewpoint of manufacturing technology, the method requires a step of peeling off the weldable sheet while leaving the fused portion thereof, which is complicated and inferior in economy.

[0004]

The present invention relates to a method for producing a laminated nonwoven fabric structure in which a thermoplastic synthetic long-fiber nonwoven layer and a natural fiber nonwoven layer are laminated. High strength, excellent flexibility, having both water absorption and hydrophobicity, medical and sanitary materials, wipes and packaging materials or household and business related materials such as household or business bags for collecting fresh dust, Another object of the present invention is to provide a method for producing a laminated nonwoven structure suitable as a material for industrial materials represented by agriculture.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention has the following configuration as its gist. (1) and the nonwoven fabric layer made of biodegradable thermoplastic synthetic long fibers, and a nonwoven layer of natural fibers are formed by mechanically entangled <br/> laminated, using an ultrasonic welding device, the alloy The growth fiber and the natural fiber are fused to form a point-like fusion area, and the natural fiber located at least at the boundary surface between the two nonwoven fabric layers in the point-like fusion area is formed in the fusion portion of the synthetic long fiber. Being integrated as a whole by being fixed in a buried state
For producing a biodegradable laminated nonwoven structure characterized by the following:
Law . (2) The biodegradable laminated nonwoven fabric according to claim 1, wherein the biodegradable thermoplastic synthetic long fiber comprises a biodegradable thermoplastic aliphatic polyester polymer which is a condensation polymer of an aliphatic glycol and an aliphatic dicarboxylic acid. A method for manufacturing a woven structure. (3) The biodegradable laminated nonwoven structure according to claim 2, wherein the biodegradable thermoplastic aliphatic polyester polymer is polyethylene succinate or polybutylene succinate .
Manufacturing method . (4) The biodegradable thermoplastic aliphatic polyester polymer exceeds 0% by weight of polyethylene succinate and
The method for producing a biodegradable laminated nonwoven structure according to claim 2, wherein the copolymer is a copolymer of 5% by weight or less and less than 100% by weight and 65% by weight or more of polybutylene succinate.

Next, the present invention will be described in detail. The biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer in the present invention is a meltblown nonwoven fabric or a spunbonded nonwoven fabric made of a biodegradable thermoplastic aliphatic polyester-based polymer fiber which is a condensation polymer of aliphatic glycol and aliphatic dicarboxylic acid. is there. The biodegradable thermoplastic aliphatic polyester-based polymer is a condensation polymer of an aliphatic glycol and an aliphatic dicarboxylic acid and has a melting point of 90 ° C. or more. For example, polyethylene oxalate, polyethylene succinate, polyethylene Examples include adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and copolymers thereof. In the present invention,
It is particularly preferable to employ polyethylene succinate and / or polybutylene succinate as the aliphatic polyester-based polymer, since nonwoven fabric characteristics suitable for the field of application targeted by the present invention can be exhibited. Polyethylene succinate and polybutylene succinate may be polyethylene succinate alone or polybutylene succinate alone or a copolymer thereof. In the case of a copolymer, polyethylene succinate and polybutylene succinate may be used. Exceeds 0% by weight and 3
5% by weight or less and 100% of polybutylene succinate
It is preferred to be less than 65% by weight and less than 65% by weight in view of the melting point and the number average molecular weight of the copolymer. That is, the content of polyethylene succinate exceeds 35% by weight (ie,
Polybutylene succinate is less than 65% by weight. )
And the melting point is less than 90 ° C., it becomes difficult to use this polymer as a long-fiber nonwoven fabric under high-temperature conditions, and since the number average molecular weight is not sufficiently improved, the fiber forming property of this polymer becomes poor. This is because the spinning property is not improved during melt spinning. In the present invention, various additives such as matting agents, pigments, light stabilizers, heat stabilizers, and antioxidants are added to the above-mentioned biodegradable thermoplastic polymer as required. It can be added within a range that does not impair the effects of the invention.

[0007] The biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer according to the present invention is a melt-blown nonwoven fabric or a spunbonded nonwoven fabric made of the above-mentioned polymer long fiber, and the long fiber is made of the above polymer alone in addition to the above-mentioned polymer. Two or more different polymers selected from the coalesced polymer may be blends blended within a range that does not impair the melt spinnability. For example, a polyester polymer and a polyolefin polymer may be used. And a blend of two different polyamide-based polymers. Further, the form of the long fiber may be such that two different polymers selected from the above-mentioned polymers are arranged in a core-sheath type or a parallel type.

[0008] Regarding the melt blown nonwoven fabric,
First, the above-mentioned polymer is used alone, or a blend of two or more different polymers selected from the above polymers is blended, or two different polymers selected from the above polymers are used. The polymer is melt-spun by a so-called melt blown method so that the polymer is arranged in a core-in-sheath type or a parallel type, that is, a pore diameter of 0.1 to 1.0 provided in a spinneret.
mm from the spinning hole, and the discharged molten polymer stream has a width of 0.1 to 0.1 mm at a temperature 20 to 50 ° C. higher than the melting temperature.
The melt blown nonwoven web can be easily obtained by drawing and thinning by a high-pressure gas flow ejected from a slit-like nozzle of about 5 mm, cooling, and then collecting and depositing it on a moving collecting surface. When the melt spinning is performed by the melt blown method, a melt flow rate value of the aliphatic polyester-based polymer measured at a temperature of 200 ° C. according to ASTM-D-1238 (L) is 100 g /
It is preferable to employ one for 10 minutes or more and 1000 g / 10 minutes or less. This melt flow rate value is 100 g / 1
If the time is less than 0 minutes, the viscosity of the polymer is too high and it is difficult to obtain a fine non-woven fabric. On the other hand, if the melt flow rate exceeds 1000 g / 10 minutes, the viscosity of the polymer is too low and the length is too long. Both of these are not preferred because the mechanical strength of the fiber, that is, the nonwoven fabric, or the spinnability during melt spinning is reduced. The spinning temperature is appropriately selected according to the melting characteristics of the polymer to be used, but is usually preferably 50 ° C. higher than the melting point of the polymer and up to 300 ° C., and the spinning temperature is set to the melting point of the polymer. If the temperature is lower than + 50 ° C., it becomes difficult to discharge the molten polymer from the spinning hole, so that the flow of the molten polymer tends to be interrupted.
If the temperature is higher than 00 ° C., the polymer is thermally decomposed, and thus both are not preferable. Further, it is preferable that the temperature of the high-pressure gas stream that pulls and narrows the discharged molten polymer stream is 20 to 50 ° C. higher than the melting temperature of the polymer stream. If the temperature is lower than + 20 ° C., the spinnability deteriorates and it becomes difficult to form long fibers. On the other hand, if the temperature exceeds the melting temperature of the polymer + 50 ° C., the discharge hole of the spinneret is gradually deteriorated due to thermal decomposition of the polymer. Dirty and reduced operability, both of which are undesirable. Further, the flow velocity of the high-pressure gas flow is usually about 80 to 300 m / sec, and the jetting direction is preferably a direction forming an angle of 5 to 55 degrees with respect to the direction of the spinning line.

Regarding the spunbond nonwoven fabric, first, the above-mentioned polymer is used alone, or a blend of two or more different polymers selected from the above-mentioned polymers is blended. Melt spinning by so-called spunbonding method in which two different polymers selected from the above are arranged in a core-in-sheath type or a side-by-side type, that is, melt spinning out from a spinneret, cooling, and taking off air sack etc. Means for taking off speed, for example, 2500 to 6
After drawing and thinning at 000 m / min, the spunbonded nonwoven web can be easily obtained by spreading using a spreader and collecting and depositing on a moving collecting surface. In this case, composite spinning is performed using two or more incompatible polymers selected from the above-mentioned polymers, and a nonwoven web is prepared in the same manner as described above. If the splitting treatment is performed to obtain splitting fibers composed of each polymer alone, a spunbond nonwoven web of ultrafine long fibers can be obtained more easily. The two or more incompatible polymers may have substantially the same melting point.
It is also possible to select a polymer having a different temperature. When the melt spinning is performed by the spunbond method, the aliphatic polyester-based polymer has a melt flow rate of 20 measured at a temperature of 200 ° C. according to ASTM-D-1238 (L).
It is preferable to use one having g / 10 minutes or more and 100 g / 10 minutes or less. This melt flow rate value is 20 g / 1
If it is less than 0 minutes, the viscosity of the polymer is too high, and the obtained nonwoven fabric has a hard texture. On the other hand, if the melt flow rate value exceeds 100 g / 10 minutes, the viscosity of the polymer is too low, and None of them is preferable because the high-speed spinning property at the time is reduced. In addition, the take-up speed is 2,500-
6000m / min, and take-up speed of 2500
If it is less than m / min, the molecular orientation of the spun fiber is not sufficiently increased, so that the mechanical properties and dimensional stability of the obtained web are not improved. On the other hand, if the take-up speed exceeds 6000 m / min, melt spinning is performed. In this case, the spinning property is deteriorated, which is not preferable.

[0010] In the case of spunbonded nonwoven fabrics, it is preferable to subject the obtained nonwoven web to a partial hot pressing treatment in order to improve its mechanical properties and dimensional stability. When the web is subjected to a partial heat-pressing treatment, a known method can be employed. For example, a method in which a point-like fusion zone is formed between long fibers using a heated emboss roller and a metal roller having a smooth surface. When the long fibers existing in the embossed pattern portion are partially hot-pressed with each other by using the heated embossing roller, the area of each pressure contact of the hot embossing roller is 0.1 to 1.0 mm ² in terms of a circle, The pressure contact area ratio is 2 to 30%, preferably 4 to 20%, and the pressure contact density is 2 to 80 points / cm ^2, preferably 4 to 60 points / c.
and m ^2, the mechanical strength and shape retention and dimensional stability of the nonwoven fabric for heat bonding zone with pressure area ratio or pressure point density less than 2% is less than 2 points / cm ² is too small decreases, whereas When the area ratio of the press contact exceeds 30% or when the density of the press contact exceeds 60 points / cm ² , the nonwoven fabric becomes rigid and the flexibility is impaired. It is preferable that the temperature of the roller is usually about 5 to 40 ° C. lower than the melting point of the aliphatic polyester polymer to be used. A nonwoven fabric having excellent strength and high flexibility can be obtained. The embossing pattern of the hot embossing roller is not particularly limited as long as the pressed area ratio is in the range of 2 to 30%.
Any shape such as a rhombus, a triangle, a T-shape, and a well may be used. The partial heat-pressing process using the hot embossing roller may be a continuous process or a separate process.

The biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer in the present invention is obtained by the above-mentioned production method. In the case of a melt-blown nonwoven fabric or a split-spunbond nonwoven fabric, the single-fiber fineness of the constituent fibers is adjusted. 1.0
Denier or less, preferably 0.2 denier or less. On the other hand, in the case of ordinary spunbonded nonwoven fabric, the single fiber fineness of the constituent fibers is 1.0 to 8.0 denier, preferably 2.0 to 5.0 denier. It should be less than denier. In the case of a melt blown nonwoven fabric or split spunbonded nonwoven fabric, by setting the single fiber fineness to 1.0 denier or less, a laminated nonwoven structure having a high bacterial barrier property and flexibility can be obtained. In the case of a nonwoven fabric, a single-fiber fineness of 1.0 denier or more and 8.0 denier or less can provide a laminated nonwoven structure excellent in mechanical properties and dimensional stability.

The biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer in the present invention has a basis weight of 10 to 70 g / m ^{2 in} the case of a melt blown nonwoven fabric or split spunbonded nonwoven fabric.
It is also preferable that the basis weight is 10 to 70 g / m ^{2 in} the case of ordinary spunbonded nonwoven fabric. If the basis weight is less than 10 g / m ² , the degree of dense overlap between the fibers is low, and the interlayer adhesive strength of the laminated nonwoven structure obtained by laminating and integrating a natural fiber nonwoven fabric with this nonwoven fabric is reduced, or the formation is reduced. Is inferior, which is not preferable. On the other hand, if the basis weight exceeds 70 g / m ² , the thickness becomes too large, and it is difficult to apply the obtained laminated nonwoven structure to, for example, a field where flexibility is required. Stimulates the skin when used as a material in the field that comes into direct contact with the skin, such as materials for daily life and related materials. In addition, after laminating a natural fiber non-woven fabric on this non-woven fabric, it is subjected to fusion treatment using an ultrasonic fusion device and integrated. In such a case, it is necessary to reduce the processing speed or supply a large amount of ultrasonic energy.

Next, with regard to the nonwoven fabric layer of the present invention in which the natural fibers are mechanically entangled with each other, the natural fibers constituting this nonwoven fabric layer include cellulose fibers such as cotton fibers and hemp fibers. In addition, various kinds of recycled short fibers represented by animal fibers such as ramie, silk short fibers, natural pulp and rayon are also included. In the present invention, as a starting material of the nonwoven fabric layer, a combed yarn that has not been subjected to bleaching processing,
It is also possible to use bleached cotton that has been bleached or various types of bristles obtained from woven or knitted fabrics. When anti-hair is used as a starting material, examples of anti-hair machines that can be used effectively include a rat machine, a knot breaker, a garnet machine, and a turning machine. The type and combination of anti-hair machines to be used depends on the shape of the fabric, such as woven or knitted fabric, and the thickness or twist strength of the constituent yarns. It is more effective to use a combination of two or more types of anti-hair machines. It is preferable that the defibration rate (%) by this anti-hair machine is in the range of 30 to 95%. When the defibration rate is less than 30%, not only the unwoven fibers are present in the card web, but also the surface of the nonwoven fabric becomes rough, and the natural fibers are three-dimensionally mechanically processed by, for example, high pressure liquid column flow treatment. When performing the entanglement, the high pressure liquid columnar flow does not penetrate the unfibrillated fiber portion sufficiently,
%, The laminated nonwoven structure obtained by laminating and integrating with the biodegradable thermoplastic synthetic long-fiber nonwoven fabric:
Sufficient surface friction strength cannot be obtained, and both are not preferred. Here, the defibration rate (%) is expressed by the following equation (1).
Is required by: Fibrillation rate (%) = (weight of bristles-weight of thread) x 100 / weight of bristles ... (1)

The natural fiber nonwoven fabric layer of the present invention comprises the above-mentioned natural fibers, and the fibers are mechanically entangled with each other. In other words, natural fibers are mechanically entangled with each other by a high-pressure liquid columnar flow treatment or needle punching treatment. In the former case, in particular, the fibers are entangled three-dimensionally to improve the bulkiness of the nonwoven fabric and improve flexibility. In order to improve the property, for example, it is preferable to use a laminated nonwoven structure obtained by laminating and integrating with the biodegradable thermoplastic synthetic long-fiber nonwoven fabric as a material for sanitary materials or living-related materials. This non-woven fabric layer is formed by using a single material selected from the above natural fiber materials or a mixture of a plurality of types of materials as a starting material, using a carding machine to prepare a card web having a predetermined basis weight, and then obtaining the card web. The obtained web can be easily obtained by subjecting the fibers to mechanical entanglement between fibers by a high-pressure liquid column flow treatment or a needle punching treatment. This card web can be selected variously according to the degree of arrangement of the constituent fibers. For example, a parallel web arranged in the traveling direction of the card machine, a web in which parallel webs are cross-laid, a random web arranged randomly, or a medium degree of both. And the like. Further, when it is desired to develop the material as a clothing material, it is preferable to use a card web in which the aspect ratio of the nonwoven fabric is approximately 1/1.

In the case of the high pressure liquid columnar flow treatment, for example, a large number of injection holes having a hole diameter of 0.05 to 1.5 mm, particularly 0.1 to 0.4 mm are arranged in one row or plural rows with a hole interval of 0.05 to 5 mm. The injection pressure is 5 to 150 kg / c.
A method is adopted in which high-pressure liquid of m ² G is ejected from the ejection hole and impinged on a card web placed on a porous support member to impart three-dimensional entanglement between fibers. The ejection holes are arranged in rows in a direction perpendicular to the direction of travel of the card web. Room temperature water or warm water can be used as the high-pressure liquid. The distance between the injection hole and the web is preferably 1 to 15 cm. This distance is 1
If the distance is less than 15 cm, the formation of the composite nonwoven fabric obtained by this treatment is disturbed. On the other hand, if the distance exceeds 15 cm, the impact force when the liquid stream collides with the laminate is reduced, and three-dimensional confounding is sufficiently caused. Not applied, neither of which is preferred. This treatment with the high pressure liquid columnar flow may be performed in at least two stages. That is, a high-pressure liquid stream having a pressure of 5 to 40 kg / cm ² G is jetted as a first-stage treatment so as to impinge on the web to preliminarily entangle the constituent fibers of the web. In this first stage of processing, the pressure of the liquid stream is 5
When the pressure is less than kg / cm ² G, the constituent fibers of the web cannot be preliminarily entangled with each other. On the other hand, when the pressure of the liquid flow exceeds 40 kg / cm ² G, a high-pressure liquid flow is jetted onto the web to cause collision. In this case, the constituent fibers of the web are disturbed by the action of the liquid flow, and the formation of the formation is disturbed and the weight of the web is uneven. Subsequently, a high-pressure liquid stream having a pressure of 50 to 150 kg / cm ² G is jetted as a second stage treatment to impinge on the web, and the constituent fibers of the web are three-dimensionally entangled to form a densely integrated structure as a whole. . In this second stage of processing, the pressure of the liquid stream is 50
If it is less than kg / cm ² G, can not be sufficiently form a three-dimensional entanglement between fibers, as described above, whereas, when the pressure of the liquid stream exceeds 150 kg / cm ² G, obtained nonwoven Both bulkiness and flexibility are not improved, and neither is preferred. Depending on the basis weight of the web, the third stage process may be performed again from the side opposite to the second stage process under the same conditions as the second stage process, following the second stage process. Thus, a nonwoven fabric in which the fibers are entangled densely on both the front and back sides can be obtained. As a porous support member for supporting the web used in performing the high-pressure liquid columnar flow treatment, a high-pressure liquid flow is applied to the web, for example, a mesh screen or a perforated plate made of a 20-100 mesh wire mesh or a synthetic resin. There is no particular limitation as long as it can penetrate. The mesh structure of the porous support member is preferably in the range of 20 lines / 25 mm to 200 lines / 25 mm, and if it is less than 20 lines / 25 mm, when the high-pressure liquid columnar stream collides with the web, the fibers become columnar. The fibers pass through the mesh screen together with the flow, and the fibers fall off.
If it exceeds 25 mm, the amount of energy required for the high-pressure liquid columnar flow to pass through the web and the mesh screen increases, and the production cost increases. After the high-pressure liquid flow treatment, excess water is removed from the treated web. In removing the excess moisture, a known method can be employed. For example, the excess water is mechanically removed to some extent using a squeezing device such as a mangle roll, and the remaining moisture is subsequently removed using a drying device such as a suction band type hot air circulation dryer to obtain a nonwoven fabric. it can.

The nonwoven fabric layer of the present invention has a basis weight of 30 to 200 g / m ^2, preferably 50 to 150 g / m ^2.
g / m ² . The basis weight is 30 g / m ²
If it is less than 1, the abundance per unit area of the natural fiber is too small to sufficiently provide the water absorption targeted by the present invention,
On the other hand, if the basis weight exceeds 200 g / m ² , the lamination with the biodegradable thermoplastic synthetic long-fiber nonwoven fabric is followed by forming a point fusion zone using an ultrasonic fusion device to obtain a laminated non-woven fabric. The peel strength of the woven structure is not sufficiently improved, and neither is preferable.

Next, a method for producing a laminated nonwoven structure according to the present invention.
In the above, the biodegradable thermoplastic synthetic long fiber non-woven fabric layer and the natural fiber non-woven fabric layer are laminated, and an ultrasonic fusion device is used.
There are, the synthetic long fibers and natural fibers and form a point-like fused area formed by fusing, and natural fibers the synthetic long located at least the boundary surface of the two non-woven layers in said point-like fused area Ru is integrated as a whole by being fixed in a state of buried in the melt of the fiber. This point-like fusion zone is an ultrasonic wave consisting of an ultrasonic transmitter called a normal horn having a frequency of 19.15 KHz and a pattern roll having a point-like or band-like convex projection on the circumference. The short fibers which are formed by using a fusion device and are in contact with the portions corresponding to the convex protrusions are fused together. More specifically, the point fusion zones have a specific area and a specific arrangement with respect to the total surface area of the nonwoven structure, and the individual point fusion zones do not necessarily have to be circular in shape. However, the ratio of the area of the whole point fusion zone to the total surface area of the nonwoven structure is 2 to 4
0%, preferably 4 to 25%, and the area density is 7 to 80 points / cm ² , preferably 8 to 50 points / cm ² . If the ratio of the area of the entire point-like fusion zone to the total surface area of the nonwoven structure is less than 2%, an ultrasonic fusion device is used after laminating the biodegradable thermoplastic synthetic long-fiber nonwoven fabric and the natural fiber nonwoven fabric. By forming the point-like fusion zone, the flexibility and bulkiness of the laminated nonwoven structure obtained by integration are reduced, and neither is preferable. Further, if the density of the area is less than 7 points / cm ² , unevenness occurs in the interlayer adhesive strength, that is, peeling strength of the obtained laminated nonwoven structure, or a bacterial barrier property in the case of a melt blown nonwoven fabric or split spunbonded nonwoven fabric. On the other hand, if the area density exceeds 80 points cm ² , the flexibility and bulkiness of the obtained laminated nonwoven structure decrease, and both are not preferred.

The ultrasonic welding device usable in the present invention includes a known device, that is, an ultrasonic oscillator called a normal horn having a frequency of 19.15 KHz, and a point-shaped or band-shaped projecting portion on the circumference. And a pattern roll comprising: The pattern roll is disposed below the ultrasonic oscillator, and the object is passed between the ultrasonic oscillator and the pattern roll. The number of convex protrusions provided on the pattern roll may be one or more, and when the number of the protrusions is plural, any of parallel or staggered arrangement may be used. During the fusion process, the horn is pressurized by applying air pressure to the horn. The linear pressure between the horn and the pattern roll is usually 1 to 10 kg / cm, and the linear pressure is 1 k.
When it is less than g / cm, the pressing force against the laminate of the thermoplastic synthetic long-fiber non-woven fabric layer and the natural fiber non-woven fabric layer is insufficient, and no fusion occurs. On the other hand, when the linear pressure exceeds 10 kg / cm, Laminates obtained by excessively high pressing pressure on the point-like fusion zone and the biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer corresponding to the fusion zone being thermally decomposed or, in extreme cases, perforation being generated The interlayer adhesion of the nonwoven structure decreases,
Neither is preferred . FIG. 1 is a schematic view showing a cross section of the point-like fusion zone in the laminated nonwoven structure obtained by the present invention. In the figure, 1 is a biodegradable thermoplastic synthetic long fiber layer melted in a point-like fusion zone, and 2 is a natural fiber. As is apparent from the figure, at least a boundary surface between both nonwoven fabric layers in a point-like fusion zone. The located natural fiber 2 is fixed in a state where the thermoplastic synthetic long fiber is buried in the melted portion where the thermoplastic synthetic fiber is melted, that is, 1 and both nonwoven fabric layers have such an adhesive structure in the point-like fusion zone, A laminated nonwoven structure having high peel strength is obtained.

[0019]

The laminated non-woven fabric structure obtained by the production method of the present invention has hydrophobicity because one side is composed of a non-woven fabric layer made of biodegradable thermoplastic synthetic long fibers, and the other side has natural fibers. Since it is composed of a non-woven fabric layer that is entangled with each other, it has water absorbency, and both non-woven fabrics have biodegradability. Further, when the thermoplastic synthetic long-fiber nonwoven fabric is a melt-blown nonwoven fabric or split spunbonded nonwoven fabric, and natural fibers are three-dimensionally entangled with each other,
Excellent flexibility is provided in synergy with the synthetic long fiber.
Furthermore, in the point-like fusion zone where the synthetic long fibers and the natural fibers are fused, the natural fibers located at least at the boundary surface between the two nonwoven fabric layers are embedded in the fused portion of the synthetic long fibers. Since it has a fixed adhesive structure, it becomes a laminated nonwoven structure having high peel strength.

[0020]

EXAMPLES Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples, the measurement of each characteristic value was performed by the following method. Melt flow rate value (g / 10 minutes): ASTM-D-
It was measured according to the method described in 1238 (L). In addition,
In the case of a biodegradable thermoplastic aliphatic polyester polymer,
The measurement temperature was 200 ° C. Melting point (° C): Differential scanning calorimeter DS manufactured by PerkinElmer
Using C-2 type, sample weight 5mg, heating rate 20 ℃
The temperature at which the maximum extremum of the melting endothermic curve obtained by measuring per minute was obtained was defined as the melting point (° C.). Basis weight (g / m ² ): 10 cm long from the sample in the standard state
After making a total of 10 specimens of 10 cm width and reaching equilibrium moisture, the weight (g) of each specimen was weighed, and the average of the obtained values was converted to unit area (m ² ). Weight (g /
m ² ). Tensile strength (kg / 5 cm width) and tensile elongation (%): Measured according to the method described in JIS-L-1096A. That is, a total of 10 sample pieces each having a sample length of 10 cm and a sample width of 5 cm were prepared, and a constant-speed elongation type tensile tester (Tensilon UTM-4 manufactured by Toyo Baldwin Co., Ltd.) was used for each sample piece in the longitudinal direction of the nonwoven fabric. 1-100)
The tensile strength is calculated using the following formula: The tensile strength (kg / 5 cm width) and the average value of the elongation percentage (%) are determined. The elongation (%) was used. Delamination strength (g / 5 cm width): A total of 10 specimens each having a sample length of 10 cm and a specimen width of 5 cm were prepared, and a constant-speed elongation type tensile tester (Toyo Bold Co., Ltd.) was prepared for each specimen in the longitudinal direction of the nonwoven fabric. Wins Tensilon UTM-4-1-10
0), the natural fiber nonwoven fabric layer is forcibly peeled off from the synthetic long fiber nonwoven fabric layer to a position of 5 cm measured from the end of the laminated structure at a pulling speed of 10 cm / min, and the obtained load value (g / 5 cm The average value of the width was calculated as the delamination strength (g / 5 cm).
Width). Softness (g): A sample length of 10 cm and a sample width of 5 cm were prepared, and a total of five sample pieces were formed. Each sample piece was bent in the horizontal direction to form a cylindrical object, and the end of each was joined. It was used as a sample for measuring the hardness. Next, each measurement sample was compressed in the axial direction at a compression rate of 5 cm / min using a constant-speed elongation-type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.). The average value of the load values (g) was defined as the softness (g). Water absorption (mm): Measured according to the birec method described in JIS-L-1096. Evaluation of biodegradability: The specimen was taken out after burying it in soil for three months, and when the specimen retained its shape, or even when it retained its tensile strength, the initial tensile strength was 50%.
%, It was evaluated that the biodegradability was good.

Example 1 A copolymer chip of 10% by weight of polyethylene succinate / 90% by weight of polybutylene succinate having a melt flow rate measured at a melting point of 110 ° C. and a temperature of 200 ° C. of 30 g / 10 minutes was used. A spunbonded nonwoven fabric consisting of long fibers of the copolymer was prepared. That is, the copolymer chip was melted using an extruder-type melt extruder, and this was passed through a spinneret having a circular cross-section spinning hole having a hole diameter of 0.35 mm, a spinning temperature of 210 ° C., and a single hole discharge amount of 0.1 mm. After melt spinning at 78 g / min, cooling using cooling air at a temperature of 20 ° C., drawing and narrowing at a take-up speed of 3500 m / min using an air sack, and then opening using an opener, A web is formed by collecting and accumulating on the moving collecting surface, and the obtained web is provided with a protruding sculpture pattern having a tip area of 0.6 mm ^{2 at} a contact area ratio of 17% and a density of 20 points /
using the provided thermal embossing roller and the surface smooth metal roller in cm ^2, a processing temperature of 95 ° C., and 40k linear pressure
g / cm, partial heat pressing at a processing speed of 10 m / min, a single fiber fineness of 2.0 denier and a basis weight of 30 g
/ M ² . The resulting spunbonded nonwoven fabric has a tensile strength of 5.3 kg / 5 cm width, a tensile elongation of 37%, a softness of 27 g, and a water absorption of 12 mm.
It was. Separately, bleached cotton with an average single fiber fineness of 1.5 denier and an average fiber length of 25 mm was used.
A nonwoven fabric in which cotton fibers are three-dimensionally entangled was prepared. That is, the bleached cotton is used as a starting material, a card web having a random fiber arrangement is prepared by a random card machine, and the obtained web is placed on a 70 mesh wire mesh moving at a moving speed of 20 m / min. Liquid flow treatment was applied. The high-pressure liquid flow treatment uses a high-pressure columnar water flow treatment device in which injection holes having a hole diameter of 0.1 mm are arranged in a line at a hole interval of 0.6 mm, and a columnar water flow is applied in two stages from a position 50 mm above the web. Was. In the first stage processing, the pressure was 30 kg / cm ² G, and in the second stage processing, the pressure was 7 kg / cm ² G.
It was 0 kg / cm ² G. The processing in the second stage was performed four times from the front side of the web, then reversed the web, and performed five times from the back side. Next, after removing excess moisture from the obtained processed material using a mangle roll, the obtained processed material is subjected to a drying treatment at a temperature of 100 ° C. using a hot-air drier so that the cotton fibers are densely three-dimensionally. A cotton fiber nonwoven fabric having a target weight of 35 g / m ² was obtained. The obtained cotton fiber nonwoven fabric has a tensile strength of 4.5 kg / 5 cm width, a tensile elongation of 35%, a softness of 28 g, and a water absorption of 132 m.
m.

Next, the spunbond nonwoven fabric obtained above and the cotton fiber nonwoven fabric are laminated, and the frequency is 19.15K.
Hz ultrasonic oscillator and dot-shaped projections on the circumference have an area ratio (ratio of area of all projections to total surface area of the roll)
Using an ultrasonic fusing apparatus consisting of 11% and pattern rolls arranged at a density of 18 points / cm ² , the processing speed was 30
m / min, linear pressure 1.5 kg / cm, ultrasonic amplitude 16
μm and subjected to an ultrasonic fusion treatment to obtain a laminated nonwoven structure. Table 1 shows the properties of the obtained laminated nonwoven structure.

Example 2 Using a polybutylene succinate chip having a melt flow rate measured at a melting point of 110 ° C. and a temperature of 200 ° C. and having a melt flow rate of 160 g / 10 minutes, a melt-blown nonwoven fabric made of the ultrafine fibers of the polymer was prepared. That is, the polymer chip is melted using an extruder-type melt extruder,
This is melted and discharged through a spinneret having a spinning hole having a hole diameter of 0.15 mm at a spinning temperature of 270 ° C. and a single hole discharge amount of 80 g / min, and the discharged molten polymer stream is heated to a temperature 30 ° C. higher than the melting temperature. A high-pressure air stream is jetted at a speed of 170 m / sec in a direction at an angle of 25 degrees with respect to the direction of the spinning line, drawn and thinned, cooled, and then placed at a position 30 cm below the spinneret. Collected and deposited on the drum,
The average single fiber fineness is 0.14 denier and the basis weight is 20 g
/ M ² of melt blown nonwoven fabric. The obtained melt blown nonwoven fabric has a tensile strength of 1.0 kg / 5 cm.
Width, tensile elongation 42%, bristles 12g, water absorption 7
mm. Next, the melt-blown non-woven fabric obtained above was laminated with the cotton fiber non-woven fabric prepared in Example 1, and thereafter a laminated non-woven structure was obtained in the same manner as in Example 1. Table 1 shows the properties of the obtained laminated nonwoven structure.

Comparative Example 1 Melting point: 156 ° C., melt flow rate: 50 g / 10
A spunbonded nonwoven fabric made of the above-mentioned polymer long fiber was prepared using a polypropylene chip of the above type. That is, the polymer chip was melted using an extruder-type melt extruder, and thereafter the same procedure as in Example 1 was carried out except that the spinning temperature was 230 ° C., and the single fiber fineness was 2.0 denier and the basis weight was 30 g. / M ² . The resulting spunbonded nonwoven fabric has a tensile strength of 8.3 kg /
It had a width of 5 cm, a tensile elongation of 38%, a softness of 38 g, and a water absorption of 10 mm. Next, the spunbonded nonwoven fabric obtained above and the cotton fiber nonwoven fabric prepared in Example 1 were laminated, and thereafter a laminated nonwoven structure was obtained in the same manner as in Example 1. Table 1 shows the properties of the obtained laminated nonwoven structure.

Comparative Example 2 The spunbonded nonwoven fabric prepared in Example 1 and the cotton fiber nonwoven fabric prepared in Example 1 were laminated, and a hot emboss roller having a pressed area ratio of 12% and a smooth surface were used instead of the ultrasonic fusion treatment. A laminated non-woven structure was produced in the same manner as in Example 1 except that a partial metal pressure treatment was performed at a processing temperature of 102 ° C., a linear pressure of 80 kg / cm, and a processing speed of 15 m / min. Obtained. Table 1 shows the properties of the obtained laminated nonwoven structure.

[0026]

[Table 1]

The laminated nonwoven structures obtained in Examples 1 and 2 have practically sufficient tensile strength and elongation as well as high peel strength, excellent flexibility, and biodegradability, as is clear from Table 1. Was provided. In particular, the laminated nonwoven structure of Example 2 used a melt-blown nonwoven fabric, and also had good bacterial barrier properties. In contrast, the laminated nonwoven structure obtained in Comparative Example 1 did not contain biodegradable fibers, and as a result of the evaluation test, was evaluated as having poor biodegradability. Since the laminated nonwoven structure obtained in Comparative Example 2 was subjected to the partial heat pressing treatment using the hot embossing roller, the peel strength was extremely low.

[0028]

The biodegradable laminated nonwoven structure obtained by the production method of the present invention comprises a biodegradable thermoplastic synthetic long-fiber nonwoven fabric layer and a nonwoven fabric layer in which natural fibers are mechanically entangled with each other. Wherein the synthetic short fibers and the natural fibers have a point fusion zone formed by fusing, and the natural fibers located at least at the boundary surface between the two nonwoven fabric layers in the point fusion zone are the synthetic lengths. No Ru der made are integrated as a whole by being fixed in a state of buried in the melt of the fiber
With biodegradability, high peel strength, excellent flexibility,
It has both water absorbency and hydrophobicity, and is used for general life related materials such as medical and sanitary materials, wiping cloths and packaging materials, household or commercial bags for collecting dust, or industrial materials represented by agriculture. It is suitable as each material.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of the point-like fusion zone in a biodegradable laminated nonwoven structure of the present invention.

[Explanation of symbols]

 1: melted biodegradable thermoplastic synthetic long fiber layer 2: natural fiber

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-214648 (JP, A) JP-A 5-230751 (JP, A) JP-A-50-47492 (JP, A) JP-A-60-1985 101118 (JP, A) JP-A-7-119010 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D04H 1/00-18/00 C68G 63/00-63/91

Claims (4)

(57) [Claims] And 1. A non-woven fabric layer made of biodegradable thermoplastic synthetic long fibers, natural fibers with each other by stacking a nonwoven fabric layer formed by mechanically entangled, using an ultrasonic welding device, wherein the synthetic filament Fusing area formed by fusing with natural fiber
Then, the natural fibers located at least at the boundary surface between the two nonwoven fabric layers in the point-like fusion zone are fixed in a state where they are buried in the fusion portion of the synthetic long fiber, thereby being integrated as a whole. Biodegradable laminated nonwoven structure
Manufacturing method . 2. The biodegradable thermoplastic synthetic polyester fiber according to claim 1, wherein the biodegradable thermoplastic synthetic long fiber comprises a biodegradable thermoplastic aliphatic polyester polymer which is a condensation polymer of an aliphatic glycol and an aliphatic dicarboxylic acid. A method for producing a laminated nonwoven structure. 3. The method for producing a biodegradable laminated nonwoven structure according to claim 2, wherein the biodegradable thermoplastic aliphatic polyester polymer is polyethylene succinate or polybutylene succinate. 4. The biodegradable thermoplastic aliphatic polyester-based polymer contains more than 0% by weight and not more than 35% by weight of polyethylene succinate, and 1% of polybutylene succinate.
The method for producing a biodegradable laminated nonwoven structure according to claim 2, which is a copolymer of less than 00% by weight and 65% by weight or more.