JP3259936B2 - Laminated nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated nonwoven fabric obtained by laminating a split nonwoven fabric containing split fibers and a cotton nonwoven fabric made of cotton fibers, and a method for producing the same. A laminated nonwoven fabric having high, excellent flexibility, excellent filter performance and water absorption, and which can be used for a wide range of applications such as medical and sanitary materials, clothing, living related materials, industrial materials, and the like. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, various types of laminated non-woven fabrics comprising a non-woven fabric composed of thermoplastic fibers and a non-woven fabric composed of natural fibers such as cotton fibers are known (Japanese Patent Publication No. 54-24506).
No.). This laminated non-woven fabric is intended to realize high tensile strength mainly by a non-woven fabric made of thermoplastic fiber and to realize good water absorption by a non-woven fabric made of cotton fiber or the like. The layers of such a laminated nonwoven fabric are bonded by various methods. For example, it is known that the two nonwoven fabrics are laminated by interposing an adhesive layer therebetween. However, when an adhesive layer is used, it becomes a film, so that the air permeability of the laminated nonwoven fabric is reduced, so that good filter performance cannot be obtained, and the flexibility of the laminated nonwoven fabric also decreases. was there.

[0003] Further, after both nonwoven fabrics are laminated, they are treated at a high temperature to soften or melt the thermoplastic fibers. At this time, the cotton fibers and the like are pressed into contact, and the thermoplastic fibers and the cotton fibers are fused. It is also known. However, according to this method, the thermoplastic fibers tend to be plate-shaped when softened or melted, and similarly to the case where the adhesive layer is used, the air permeability of the laminated nonwoven fabric is reduced and good filter performance is obtained. And the flexibility of the laminated nonwoven fabric is reduced.
For this reason, it is conceivable to use a composite fiber in which a low melting point component and a high melting point component are compounded in a side-by-side type or a core-sheath type as a thermoplastic fiber. In this case,
The low melting point component is softened or melted, but the high melting point component is not softened or melted. Therefore, it is considered that the low melting point component is hardly formed into a plate shape and the above-mentioned disadvantage is solved. However, in the case of the conjugate fiber, since the low melting point component and the high melting point component are in close contact with each other, the cotton fiber and the like are not sufficiently embedded in the softened or melted low melting point component, and the cotton fiber and the like are not buried in heat. There was a tendency that the fusion with the plastic fiber was not sufficient. Accordingly, there is a disadvantage that the bonding strength between the layers of the two nonwoven fabrics is weak, and the layers are easily delaminated.

[0004]

Therefore, the present invention uses a thermoplastic fiber obtained by splitting a composite fiber composed of a low-melting component and a high-melting component into a low-melting component. Eliminates the state of close contact with the high melting point component, so that the cotton fiber is sufficiently embedded in the low melting point component, and increases the delamination strength between the non-woven fabric made of thermoplastic fiber and the non-woven fabric made of cotton fiber, and It is intended to prevent the flexibility and air permeability of the laminated nonwoven fabric from being reduced.

[0005]

That is, the present invention relates to a fiber-forming polymer A, which is incompatible with the polymer A and has a melting point lower by 30 to 180 ° C. than the melting point of the polymer A. Fineness composed of the polymer A, which is formed by splitting a splittable bicomponent conjugate fiber in which the fiber-forming polymer B having a splitting ratio is divided into 60% or more. .05-
A split nonwoven fabric containing 0.8 denier split fiber A and a polymer fiber B having a fineness of 0.05 to 2 denier composed of the polymer B, and cotton formed by entanglement between cotton fibers. A non-woven fabric and a laminated non-woven fabric, the split non-woven fabric and the cotton fibers located at least at the boundary surface of the cotton non-woven fabric,
The split non-woven fabric and the cotton non-woven fabric are bonded together by a fixing area fixed while being buried in the melted split fiber B. In the fixing area, the split fiber A is
The present invention relates to a laminated nonwoven fabric characterized by being substantially unmelted and a method for producing the same.

First, the split nonwoven fabric used in the present invention will be described. This splitting nonwoven fabric is split into split type bicomponent composite fibers so that the splitting rate is 60% or more.
It mainly contains the obtained split fiber.

The splittable bicomponent conjugate fiber used here is a fiber-forming polymer A and a fiber polymer B which are conjugated so that splitting is possible independently of each other. , And have a cross section as shown in FIGS. In FIGS. 1 to 4, a hatched portion indicates the polymer A, and a dotted portion indicates the polymer B. Polymer B is
It is incompatible with the polymer A. The reason that the polymer A and the polymer B are incompatible is to make the polymers A and B easily split and split by giving an impact or the like. The melting point of the polymer B is 30 to 180 ° C. lower than the melting point of the polymer A. Polymer B has a melting point
If the temperature is higher than the above range, when the polymer A is softened or melted, the polymer B is also easily softened, and the polymers A and B are fused to each other to form a plate, and the air permeability and the flexibility are increased. This is not preferable because a laminated nonwoven fabric excellent in quality cannot be obtained.
Conversely, if the melting point of the polymer B is lower than the above range, it becomes difficult to produce a splittable bicomponent conjugate fiber composed of the polymers A and B by a melt spinning method. In addition,
The melting points of the polymers A and B are measured by the following method. That is, the temperature giving the maximum value of the melting endothermic peak obtained by raising the temperature from room temperature at a heating rate of 20 ° C./min using a DSC-2 type differential scanning calorimeter manufactured by Perkin Elmer Co., Ltd. was defined as the melting point.

The split type bicomponent composite fibers formed of the polymers A and B are generally used in the form of continuous fibers, but may be used in the form of staple fibers. The fineness of the splittable bicomponent composite fiber can be arbitrarily set, but is generally preferably in the range of 2 to 10 denier. When the fineness is less than 2 denier, it tends to be difficult to obtain a splittable bicomponent conjugate fiber by a melt spinning method. Conversely, if the fineness exceeds 10 denier,
The fineness of the split fiber A made of the polymer A or the split fiber B made of the polymer B formed after split splitting becomes too large, and the flexibility of the obtained laminated nonwoven fabric tends to decrease.

As a specific combination of the polymer A and the polymer B (Polymer A / Polymer B), typically, a polyamide-based polymer / polyolefin-based polymer, a polyester-based polymer / polyolefin-based polymer are used. Coalescence, polyamide-based polymer / polyester-based polymer, and the like. Other than this, any combination is adopted as desired. In particular, when a combination of a polyester-based polymer / polyolefin-based polymer is adopted, since both are excellent in hydrophobicity, the contradictory properties of water absorption on one side and hydrophobicity on the other side are shown on the front and back surfaces. The resulting laminated nonwoven fabric is obtained.

Examples of the above-mentioned polyolefin polymers include ethylene, propylene, butene-1, penten-1,
3-methylbutene-1, hexene-1, octene-1, dodecene
Aliphatic α having 2 to 16 carbon atoms, such as -1, octadecene-1
A homopolyolefin obtained by homopolymerizing a monoolefin or a copolymerized polyolefin obtained by mixing and polymerizing a monoolefin. Aliphatic α-monoolefins may also include other olefins and / or minor amounts (up to about 10% of the polymer weight) of other ethylenically unsaturated monomers such as butadiene, isoprene, pentadiene-1,3, styrene, α -It may be copolymerized with an ethylenically unsaturated monomer such as methylstyrene. In particular, when polyethylene is used as the polyolefin-based resin, propylene, butane-1, hexene-1, octene up to about 10% by weight of the polymer may be used.
Those obtained by copolymerizing a higher α-olefin such as -1 are preferred.

Examples of the above-mentioned polyamide polymers include nylon-4, nylon-46, nylon-6 and nylon-
66, nylon-610, nylon 11, nylon-12, polymeta-xylene adipamide (MXD-6), polyparaxylenedecaneamide (PXD-12), polybiscyclohexylmethanedecaneamide (PCM-12), etc. Is done. Further, a copolymer polyamide in which a plurality of monomers constituting such a polyamide-based polymer are used can also be used.

Examples of the above-mentioned polyester polymers include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid and naphthalene-2,6-dicarboxylic acid, and fatty acids such as adipic acid and sebacic acid as acid components. Using aliphatic dicarboxylic acids and esters thereof, ethylene glycol, diethylene glycol,
A homopolyester or a copolyester obtained by using a diol compound such as 1,4-butanediol, neopentyl glycol, cyclohexane-1,4-dimethanol and condensing the two is used. Further, in this polyester and the like, paraoxybenzoic acid, 5-sodium sulfoisophthalic acid, polyalkylene glycol,
Pentaerythritol, bisphenol A or the like may be added, or copolymerized.

As the other polymer for forming the polymer A or B, for example, a vinyl polymer can be used. Specifically, polyvinyl alcohol, polyvinyl acetate, polyacrylate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride and the like are used. Further, those obtained by copolymerizing various monomers constituting these are also used. As the polymer other than the vinyl polymer, a polyphenylene polymer or a copolymer thereof can also be used.

Polymers A and B may contain any of matting agents, pigments, flame retardants, deodorants, antistatic agents, antioxidants, ultraviolet absorbers and the like as long as the objects of the present invention are not impaired. Additives may be added.

The splittable bicomponent conjugate fiber of the present invention can be generally produced by the following method. That is, using polymers A and B, spinning is performed by a conventionally known melt composite spinning method, and is cooled by spraying air using a conventionally known cooling device such as a horizontal spraying or an annular spraying, and then generally air is cooled. Using soccer, it is towed and thinned to the desired fineness and then taken. At this time, the towing speed is more than 3000m / min,
In particular, it is preferably 4000 m / min or more. This is because a high-strength splittable bicomponent conjugate fiber can be obtained, the tensile strength of the split nonwoven fabric obtained is improved, and the dimensional stability is improved.

In order to obtain a split nonwoven fabric using the splittable bicomponent conjugate fiber thus obtained, for example, the following method is used. That is, the split-type bicomponent composite fiber pulled by using air soccer and then discharged from air soccer is generally passed through a corona discharge area in a high piezoelectric field or a frictional collision zone, Charge open. Then, the fibers are accumulated on a moving deposition device such as a conveyor made of a screen to obtain a fiber assembly. The basis weight of this fiber assembly is preferably about 150 g / m ² or less. Weight
If it exceeds 150 g / m ² , even after the split splitting process,
Substantially, there is a tendency that split type bicomponent conjugate fibers cannot be split and split throughout the entire thickness of the fiber assembly. That is, undivided split bicomponent conjugate fibers tend to remain at the center of the thickness of the split nonwoven fabric. However, even in such a case, since split fibers split and split exist on at least one surface of the split nonwoven fabric, it is still an embodiment of the present invention.

As a method for splitting the splittable bicomponent conjugate fibers in the fiber assembly, the following method can be used. For example, (a) needle punching the fiber assembly, by giving a needle impact to the split-type bicomponent composite fiber, splitting splitting method, (b) applying a drug to the fiber assembly, polymer A method of dissolving a part of the surface of A or B and splitting the splittable bicomponent conjugate fiber,
(c) applying a high-pressure liquid flow to the fiber assembly, and splitting the split-type bicomponent composite fiber by this impact, (d)
A method in which a fibrous aggregate is put into a flowing liquid to give a fir action or a mechanical fir action to give a split type bicomponent composite fiber by its buckling force. No. In the present invention, this split splitting method may adopt any method, (c)
Alternatively, it is preferable to employ the method (d). According to these methods, it is possible to obtain a low-weight, high-quality split nonwoven fabric. In addition, these methods are also less likely to cause pollution, and are simple and economical.

According to the split splitting method exemplified above, the polymer A and the polymer B existing in the split type bicomponent conjugate fiber are separated, and the splitting fiber A composed of the polymer A is separated from the splitting fiber A. It is split and split into split fibers B composed of the polymer B. Split splitting is rarely generated at all portions of the split type bicomponent conjugate fiber, and split splitting and unsplit splitting are generally mixed. In the present invention, it is necessary that the splitting rate indicating the ratio of splitting points is 60% or more, preferably 80% or more, more preferably 90%.
As described above, the content is most preferably 95 to 98%. When the splitting rate is less than 60%, splitting fiber B composed of polymer B
And the number of places where the polymer B and the polymer A are in close contact with each other without being separated increases. Therefore, the split non-woven fabric in such a state is processed at a high temperature,
Even if the polymer B is softened or melted and the cotton fibers in the cotton nonwoven fabric are buried, since they are in close contact with the polymer A, they are not sufficiently buried and a laminated nonwoven fabric having a high delamination strength cannot be obtained. Is not preferred. Here, the splitting rate is selected at any 10 locations of the splitting nonwoven fabric, the cross section is magnified 100 times and a cross-sectional photograph is taken, and then, from the 10 cross-sectional photographs, calculated by the following formula It means the average value of things. Note: Splitting rate (%) = (N / M) × 100 (where N represents the total number of splitting fibers A and B that have been split completely, and M is the number of split split fibers and undivided split fibers. Represents the total number of

In the present invention, the fineness of the split fiber A after split splitting is from 0.05 to 0.8 denier, preferably from 0.08 to 0.5 denier, more preferably from 0.1 to 0.3 denier. If the fineness of the split fiber A exceeds 0.8 denier, the diameter of the split fiber A is too large, the rigidity is increased, and the flexibility of the obtained laminated nonwoven fabric is unfavorably reduced. Conversely, it is difficult to make the split fiber A less than 0.05 denier in production. That is, it is practically difficult to spin such a fine denier fiber by the melt composite spinning method, and it becomes difficult to obtain a splittable bicomponent composite fiber at low cost or rationally.

On the other hand, the fineness of split fiber B after split splitting may be slightly larger than the fineness of split fiber A. Because the split fiber B is softened or melted in a later step and has a role of embedding the cotton fiber, its rigidity directly affects the laminated nonwoven fabric, and the flexibility is extremely increased. This is because it does not lower it. However, the fineness of the split fiber B also needs to be 0.05 to 2 denier, preferably 0.08 to 1.5 denier, and more preferably 0.1 to 1 denier. When the fineness of the split fiber B exceeds 2 denier, if the whole split fiber B is not heat-treated, the split fiber B which is softened or melted and does not embed the cotton fiber exists. ,by this,
It is not preferable because the flexibility of the obtained laminated nonwoven fabric is reduced. Conversely, it is difficult to reduce the fineness of the split fiber B to less than 0.05 denier, as in the case of the split fiber A.

In the present invention, such a split nonwoven fabric is laminated with a cotton nonwoven fabric. In the cotton nonwoven fabric, the cotton fibers are entangled with each other and maintain a constant shape.
As the cotton fibers used here, combed cotton that has not been subjected to bleaching processing, bleached cotton that has been bleached, or bristles obtained from a woven or knitted fabric are used. In order to obtain anti-hair, an anti-hair machine such as a rag machine, a knot breaker, a garnet machine, and a turning machine is used. Depending on the fabric shape of the woven or knitted fabric to be woolen or the thickness of the yarns constituting the woven or knitted fabric and the strength of the twist, a plurality of the same woolen machines are connected in series. Or use a combination of two or more anti-hair machines. In the case of using an anti-hairing machine, it is preferable that the opening rate is in the range of 30 to 95%. If the opening rate is less than 30%, since many unspread cotton fibers are present in the card web, not only does the resulting cotton nonwoven fabric have a roughness but also, for example, the cotton fibers are separated by a high-pressure liquid flow. Even in the case of three-dimensional confounding, the high-pressure liquid flow hardly penetrates the unspread cotton fiber portion, and it tends to be difficult to obtain sufficient three-dimensional confounding. Conversely, if the opening rate exceeds 95%, the fiber length of the re-haired cotton fibers tends to be shorter,
The cotton fibers tend to fall off from the surface of the obtained cotton nonwoven fabric, and it tends to be difficult to obtain a sufficient surface frictional strength. Here, the fiber opening ratio is obtained by the following equation. Opening ratio (%) = [(weight of bristles-weight of cotton fiber) / weight of bristles] × 100

The cotton nonwoven fabric is one in which cotton fibers are entangled with each other. This confounding can be easily obtained by subjecting the cotton fiber aggregate to a needle punching treatment or a high-pressure liquid flow treatment. In particular, when high-pressure liquid flow treatment is performed, the cotton fibers are three-dimensionally entangled with each other, so that the tensile strength and the like of the cotton nonwoven fabric are improved, and the flexibility is improved. In particular, when obtaining a laminated nonwoven fabric for sanitary materials or for living related materials,
It is preferable to use such a three-dimensionally entangled cotton nonwoven fabric.

The following method can be exemplified as a specific method for producing a cotton nonwoven fabric. Using a carding machine, the cotton fibers are spread to create a card web with a predetermined basis weight. Examples of the card web include a parallel web in which cotton fibers are arranged in accordance with a traveling method of a card machine, a cross lay web in which parallel webs are cross-laid, a random web in which cotton fibers are randomly arranged, or a parallel with a random web. Any card web, such as a semi-random web, which is in an intermediate state of the web, can be used. In particular, when it is desired to develop the laminated nonwoven fabric according to the present invention as a material for clothing, a card web (specifically, a crosslay web or a crosslay web) in which the length / width ratio of the tensile strength of a cotton nonwoven fabric is approximately 1/1. It is preferred to use random webs).

Next, the web is subjected to a needle punching process or a high-pressure liquid flow process. When high-pressure liquid flow treatment is performed, for example, a device in which 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 a row or a plurality of rows at a hole interval of 0.05 to 5 mm, and the injection pressure is 5 to 150 kg / cm. ^{This is done} by injecting a ² G high-pressure liquid and impinging the liquid stream against a card web placed on a porous support member. Due to the kinetic energy of this liquid stream, the cotton fibers are entangled three-dimensionally. The arrangement of the injection holes is arranged in a row in a direction orthogonal to the traveling direction of the card web. Normal-temperature water or warm water can be used as the high-pressure liquid.
The distance between the injection holes and the web is preferably between 1 and 15 cm. If this distance is less than 1 cm, the formation of the cotton nonwoven fabric obtained by this treatment tends to be disturbed. Conversely, if this distance exceeds 15 cm, the kinetic energy of the liquid stream when it collides with the web is reduced, and the three-dimensional confounding tends to be insufficient.

The treatment with the high-pressure liquid stream may be performed in at least two stages. That is, as a first stage treatment, a high-pressure liquid stream having an injection pressure of 5 to 40 kg / cm ² G is injected to collide with the web, and the cotton fibers in the web are preliminarily entangled. In the first-stage treatment, if the pressure of the liquid stream is less than 5 kg / cm ² G, there is a tendency that the cotton fibers in the web cannot be preliminarily entangled. Conversely, if the pressure of the liquid flow exceeds 40 kg / cm ² G, the kinetic energy of the liquid flow will be too large, and the cotton fibers in the web will be easily disturbed. It tends to be easier. The subsequent second stage treatment involves injecting a high pressure liquid stream at an injection pressure of 50-150 kg / cm ² G to impinge on the pre-entangled web. Then, the cotton fibers in the web are further three-dimensionally entangled to form a cotton nonwoven fabric which is dense and has sufficient tensile strength as a whole. In this second stage treatment, if the pressure of the liquid stream is less than 50 kg / cm ² G, the kinetic energy will be too small to further three-dimensionally entangle the cotton fibers in the pre-entangled web. Is not enough. Conversely, if the pressure of the liquid flow exceeds 150 kg / cm 2 G, the resulting cotton nonwoven fabric will be too dense, and the bulkiness and flexibility will tend to be reduced. Depending on the basis weight of the web, the same conditions as those of the second-stage processing may be applied to the side (reverse web surface) opposite to the second-stage processing as the third-stage processing following the second-stage processing. By performing the treatment again, it is possible to obtain a cotton nonwoven fabric in which cotton fibers are entangled densely on both sides.

As the porous support member for supporting the web used in the high-pressure liquid flow treatment, for example, a perforated plate, a mesh screen made of a wire mesh or a synthetic resin is used. In essence, anything that allows the high pressure liquid stream to penetrate the web may be used. When using a mesh screen, it is preferable to use a screen having a pore size of 20 to 200 mesh. If the pore size is less than 20 mesh, the pores are too large and the cotton fibers in the web along with the high pressure liquid stream may pass through the mesh screen and fall off. Conversely, if the pore size exceeds 200 mesh, the pore size will be too small and the used high pressure liquid stream will tend to stay on the surface of the mesh screen.

[0027] The cotton nonwoven fabric obtained by the high-pressure liquid flow treatment contains an excess of water. Therefore, it is necessary to remove or evaporate this water. For example, a web containing excess water is squeezed using a squeezing device such as a mangle roll, and the excess water is mechanically removed to some extent. And
The remaining moisture is evaporated by using a drying device such as a suction band type hot air circulation type dryer to obtain a cotton nonwoven fabric usable in the present invention.

Although the cotton nonwoven fabric is obtained by the above exemplified method, the present invention is not limited to this method, and the cotton nonwoven fabric may be obtained by other methods.
The basis weight of the cotton nonwoven fabric is preferably 30 to 200 g / m ² ,
In particular, it is more preferably 50 to 150 g / m ² . When the basis weight of the cotton non-woven fabric is less than 30 g / m ² , the amount of the cotton fiber per unit area is too small, so that a laminated non-woven fabric excellent in water absorption tends to be not obtained. Conversely, 200 g / m ²
If it exceeds, the cotton nonwoven fabric becomes thick and the flexibility tends to decrease.

The split non-woven fabric and the cotton non-woven fabric are laminated and heat-treated to soften or melt the split fibers B in the split non-woven fabric. By burying the cotton fibers in the non-woven fabric,
At the boundary between the split nonwoven fabric and the cotton nonwoven fabric, both split fiber B and the cotton fiber are bonded and fixed, and the split nonwoven fabric and the cotton nonwoven fabric are bonded. The binding and fixing of the split fiber B and the cotton fiber may be performed in the entire area of the boundary surface between the split non-woven fabric and the cotton non-woven fabric, or may be performed only in a part of the area. In particular, it is preferable to fix and bond in only a part of the area, since the flexibility of the obtained laminated nonwoven fabric is not easily reduced. When bonding and fixing in some areas, the area of the area is preferably 4 to 50%, particularly 8 to 25% with respect to the entire area of the boundary surface between the split nonwoven fabric and the cotton nonwoven fabric. Is more preferred.
If the area for bonding and fixing is less than 4%, the peel strength between the split nonwoven fabric and the cotton nonwoven fabric tends to decrease. Conversely, if the area for bonding and fixing exceeds 50%, the flexibility and bulkiness of the laminated nonwoven fabric tend to decrease.

In the case where the fixing is performed only in a part of the area, it is preferable that the area is arranged without being unevenly distributed. When they are unevenly arranged, the properties of the obtained laminated nonwoven fabric tend to be non-uniform. In the scattered arrangement, the shape of each point is generally circular, but may be arbitrary. Further, they may be arranged in a belt shape with a certain interval.

In the present invention, as a method for laminating and bonding the split nonwoven fabric and the cotton nonwoven fabric, for example, the following method is preferably employed. That is, it is preferable to introduce a laminate obtained by laminating the split-fiber non-woven fabric and the cotton non-woven fabric into an ultrasonic fusing machine and bond them. The ultrasonic fusion machine is a device that softens or melts the split fiber B by ultrasonic waves. Specifically, it comprises an ultrasonic oscillator 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 convex protrusions provided on the pattern roll may be in one row or a plurality of rows, and when the arrangement is in a plurality of rows, any of a parallel or a staggered arrangement may be used. .

In the present invention, the laminate is passed between the ultrasonic oscillator and the pattern roll. Then, due to the action of the ultrasonic wave oscillated from the ultrasonic oscillator, the split fiber B is softened or melted by frictional heat at the portion of the laminate contacting the convex protrusion. At this time, the horn is pressurized by applying air pressure. The linear pressure between the horn and the pattern roll is usually about 1 to 10 kg / cm. By applying such a linear pressure, the cotton fiber is embedded in the softened or melted split fiber B, and is bonded and fixed. When the linear pressure is less than 1 kg / cm, the cotton fibers are not buried in the softened or melted split fiber B, and the peel strength between the split nonwoven fabric and the cotton nonwoven fabric tends to decrease. Conversely, if the linear pressure exceeds 10 kg / cm, split fibers B may be thermally decomposed or holes may be formed in the laminated nonwoven fabric. As is clear from this description, if the shape of the tip of the convex projection is circular, the areas fixed and fixed will be arranged in a scattered manner. In addition, if the tip of the protruding projection is in the form of a band, the areas fixed and fixed are arranged in a band at a constant interval.

As described above, in the present invention, it is general to use an ultrasonic fusion device to form a joint fixing area. The use of a hot embossing device instead of an ultrasonic fusing device makes it difficult to create an area for bonding and fixing. A hot embossing device is typically composed of a heated embossing roll having convex protrusions on its surface and a smooth roll having a smooth surface, but a softened or melted splitting material such as an ultrasonic fusing device. It is difficult to embed a cotton fiber in the fiber B. Although the reason is not clear, it is considered that the split fiber B is softened or melted. Therefore, even when a hot embossing device is used, cotton fibers can be satisfactorily embedded in the split fiber B by strictly setting the conditions such as the linear pressure and the heating temperature. Because of the difficulty, it is difficult to adopt this method.

An example of the laminated nonwoven fabric according to the present invention is shown in FIGS. 5 and 6. FIG. 5 schematically shows a cross section of the laminated nonwoven fabric, in which split nonwoven fabric (hatched portion) and cotton nonwoven fabric (white background portion) are bonded, and a fixed area (necking) X). FIG. 6 is a diagram schematically illustrating an enlarged view of the necking portion X. As is clear from FIG. 6, the cotton fiber is fixed in a state where it is embedded in the melted portion of the split fiber B. Therefore, the peel strength between the split nonwoven fabric and the cotton nonwoven fabric can be improved.

Next, the present invention will be described more specifically based on examples. The measuring method of each characteristic value and the like used in this embodiment is performed by the following method. [Polymer melting point]: Temperature at which the maximum value of the melting endothermic peak obtained by raising the temperature from room temperature using a DSC-2 type differential scanning calorimeter manufactured by Perkin Elmer at a temperature rising rate of 20 ° C./min. Was taken as the melting point. [Fineness of split fiber]: Determined by calculating the cross-sectional area from the shape and dimensions in an electron micrograph and correcting the density. [Tensile strength of laminated nonwoven fabric]: A value obtained by measuring the maximum tensile strength from a test piece having a width of 5 cm and a length of 10 cm according to the strip method described in JIS L-1096, and converting it to a basis weight of 100 g / m ² .
In addition, the tensile strength measured the longitudinal direction and the horizontal direction. Here, the tensile strength in the longitudinal direction is the tensile strength in the machine direction, and the tensile strength in the lateral direction is the tensile strength in a direction perpendicular to the machine direction. [Tensile elongation of laminated nonwoven fabric]: Elongation at the time of cutting when measuring tensile strength. The elongation was also measured in the vertical and horizontal directions. [Delamination strength of laminated nonwoven fabric]: A test piece having a width of 5 cm and a length of 10 cm was collected from the laminated nonwoven fabric such that the length direction was the vertical direction. Using a constant-speed elongation type tensile tester, one end of the split non-woven fabric in the laminated non-woven fabric is sandwiched by one chuck, and the end of the cotton non-woven fabric is sandwiched by the other chuck, at a tensile speed of 10 cm / min. The average value of the load values at the time of peeling was defined as the delamination strength of the laminated nonwoven fabric. [Rigid-softness of laminated nonwoven fabric]: A test piece having a width of 5 cm and a length of 10 cm was bent in the length direction to form a cylindrical body, and a joint between the abutting ends was used as a bending-softness measurement sample. The sample was compressed in the axial direction (width direction of the test piece) at a compression rate of 5 cm / min using a constant-speed elongation type tensile tester, and the average of the obtained maximum load values was calculated as the bending resistance of the laminated nonwoven fabric. And [Air permeability of laminated nonwoven fabric]: Measured according to the Frazier method described in JIS L-1096. [Water absorbency of laminated nonwoven fabric]: Measured according to the Bilek method described in JIS L-1096.

[0036]

【Example】

Example 1 As the fiber-forming polymer A, polyethylene terephthalate having a melting point of 258 ° C. and [η] of 0.7 obtained by measurement in a mixed solvent of phenol / chloroethane = 1/1 at 20 ° C. was prepared. On the other hand, the melting point of the fiber-forming polymer B is 128 ° C.
A polyethylene having a melt index value (measured according to the method described in ASTM D1238 (E)) of 25 g / 10 minutes was prepared. Then, using a composite spinneret in which the obtained fiber cross-section is in the form shown in FIG. 1 and the total number of divisions is 24, so that the composite ratio of polymer A and polymer B is 1: 1 by weight, Extrusion was performed at a single hole discharge rate of 1.2 g / min. Thus, the composite melt spinning was performed to obtain a split type bicomponent composite continuous fiber.

After cooling the spun yarn, the yarn is taken up by air soccer at a speed of 4500 m / min, opened by a corona discharge opening device, and collected and deposited on a moving collecting surface to obtain a fiber assembly. I got This fiber assembly was introduced into a hot embosser to obtain a fiber fleece having a basis weight of 30 g / m ² . The embossing roll provided in the hot embossing device has scattered convex portions at a ratio of 5% to the roll surface area, and has a temperature of 6%.
It was set at 0 ° C. The fineness of the split type bicomponent conjugate continuous fiber collected from the fiber assembly is
It was about 2.5 denier.

Next, the fiber fleece was squeezed at a speed of 20 m /
After being placed on a 100-mesh screen moving in minutes and applying water with a water application device, the fiber fleece is subjected to high-pressure liquid flow treatment to split the split type bicomponent composite continuous fiber. Was done. This treatment is performed above the fiber fleece
The injection hole was positioned at 5 cm, and the fiber fleece was subjected to a high-pressure liquid flow treatment three times on each of the front and back sides under a water pressure of 50 kg / cm ² G. After this, excess water is squeezed out with mangle rolls,
Treated with a drying and heat treatment device kept at 98 ° C,
A split nonwoven fabric was obtained. The split nonwoven fabric is split at a split rate of 91%, and the split fiber A (polyethylene terephthalate, ie, split fiber composed of polymer A) is generated.
Has a denier of 0.1 denier, and the split fiber B
(Polyethylene, split fiber composed of polymer B)
Also had a fineness of 0.1 denier.

On the other hand, using a cotton fiber (cotton bleached cotton) having an average fineness of 1.5 denier and an average fiber length of 25 mm, a cotton nonwoven fabric in which cotton fibers are three-dimensionally entangled as follows. Manufactured. That is, with a random card machine,
A random card web in which cotton fibers are randomly arranged is prepared, and the obtained web is fed to a 70-mesh screen moving at a speed of 20 m / min, subjected to high-pressure liquid flow treatment, and subjected to three-dimensional entanglement. Processing was performed. In the high pressure liquid flow treatment, the injection hole was positioned 5 cm above the web, and the high pressure liquid flow was applied in two stages. In the process of the first stage, the water pressure 30kg / cm ² G, in the processing in the second stage pressure 70 kg / cm ²
G. In the treatment in the second stage, the high-pressure liquid flow was applied twice from the front and back of the web. Thereafter, excess water was squeezed and removed with a mangle roll, and treated with a drying / heat treatment apparatus kept at 98 ° C. to obtain a cotton nonwoven fabric.

Next, a laminate obtained by laminating split-spun non-woven fabric and cotton non-woven fabric was subjected to an ultrasonic oscillator (horn) having a frequency of 19.15 KHZ, and a pattern roll provided with scattered projections on the circumference. And embedded in the splitting fiber B at the boundary cotton between the splitting nonwoven fabric and the cotton nonwoven fabric and fixed, and a laminated nonwoven fabric having a basis weight of 60 g / m ² is obtained. Obtained. Here, in the used pattern roll, the convex protrusions were provided at a rate of 10% with respect to the roll surface area. The linear pressure between the convex protrusion and the horn is 2.
5 kg / cm and the speed of the laminate moving through the ultrasonic fusing machine was 20 m / min. The area in which the cotton fibers were embedded and fixed was only the area in the laminated nonwoven fabric that was in contact with the convex protrusion.

The properties of the laminated nonwoven fabric obtained as described above were as shown in Table 1.

[Table 1]

Example 2 Nylon 6 having a relative viscosity of 2.65 measured at 25 ° C. in concentrated sulfuric acid having a melting point of 225 ° C. and 96% in place of the polyethylene (fiber-forming polymer B) used in Example 1 Except for using, a splittable conjugate continuous fiber was obtained in the same manner as in Example 1.

Then, the take-up speed of air soccer is
A fiber assembly was obtained in the same manner as in Example 1 except that the flow rate was changed to 4600 m / min. Thereafter, a fiber fleece was obtained in the same manner as in Example 1 except that the temperature of the embossing roll was changed to 150 ° C. The fineness of the split type bicomponent conjugate continuous fibers collected from the fiber aggregate was about 2.3 denier.

A split non-woven fabric was obtained in the same manner as in Example 1 except that the jet pressure of the high-pressure liquid stream was changed to 60 kg / cm ² G. This split non-woven fabric is split at a split rate of 95%, and the split fiber A (polyethylene terephthalate, split fiber composed of polymer A) has a fineness of 0.1 denier. The fineness of the generated split fiber B (split fiber composed of nylon 6, ie, polymer B) was also 0.1 denier.

Next, using the cotton nonwoven fabric used in Example 1, a laminated nonwoven fabric having a basis weight of 60 g / m ² was obtained in the same manner as in Example 1. The properties of the laminated nonwoven fabric obtained as described above were as shown in Table 1.

Example 3 The same fiber-forming polymers A and B as those used in Example 2 were prepared. Then, using a composite spinneret in which the obtained fiber cross-section is as shown in FIG. 3 and the total number of divisions of polyethylene terephthalate is 8, polymer A
And polymer B were extruded at a single hole discharge rate of 1.8 g / min such that the composite ratio was 1: 1 by weight. Thus, the composite melt spinning was performed to obtain a split type bicomponent composite continuous fiber.

Then, the pick-up speed of air soccer is
A fiber assembly was obtained and then a fiber fleece was obtained in the same manner as in Example 2 except that the speed was set to 4700 m / min. The fineness of the split type bicomponent composite continuous fiber collected from the fiber assembly was about 3.4 denier. Thereafter, a split nonwoven fabric was obtained in the same manner as in Example 2. This splitting nonwoven has a splitting rate
The split fibers are split at 95%, and the fineness of the split fibers A (polyethylene terephthalate, split fibers composed of polymer A) is 0.2 denier, while the split fibers B (nylon 6 That is, the fineness of the split fiber composed of the polymer B) was 1.7 denier.

Next, using the cotton nonwoven fabric used in Example 1, a laminated nonwoven fabric having a basis weight of 60 g / m ² was obtained in the same manner as in Example 1. The properties of the laminated nonwoven fabric obtained as described above were as shown in Table 1.

Example 4 The same procedure as in Example 3 was carried out except that a pattern roll constituting the ultrasonic welding machine was provided with a convex projection at a ratio of 30% to the roll surface area. 60
g / m ² of the laminated nonwoven fabric was obtained. The properties of the laminated nonwoven fabric obtained as described above were as shown in Table 1.

Comparative Example 1 The polyethylene terephthalate and polyethylene used in Example 1 were spun under the following conditions using a core-sheath type composite spinneret, and polyethylene terephthalate was used as a core and polyethylene was used as a sheath. To obtain a core-sheath type bicomponent continuous fiber. That is, the composite ratio of polyethylene terephthalate and polyethylene was 1: 1 by weight, and the single hole discharge rate was 1.2 g / min.

The pick-up speed by air soccer is 4800
A fiber assembly was obtained and then a fiber fleece was obtained in the same manner as in Example 1 except that m / min was used. The fineness of the core-sheath type bicomponent composite continuous fiber collected from the fiber aggregate is about
It was 2.3 denier. Thereafter, the cotton nonwoven fabric used in Example 1 was used, and the cotton nonwoven fabric and the fiber fleece were laminated. Then, a laminated nonwoven fabric having a basis weight of 60 g / m ² was obtained in the same manner as in Example 1. The properties of the laminated nonwoven fabric obtained as described above were as shown in Table 1.

Comparative Example 2 The same polyethylene terephthalate as in Example 1 was extruded using a single-phase spinneret at a single-hole discharge rate of 1.2 g / min. Thus, a one-component continuous fiber was obtained.
5000m /
Minute, and thereafter, as in Example 2, a fiber aggregate was obtained, and then a fiber fleece was obtained. The fineness of the one-component continuous fiber collected from the fiber aggregate was about 2.2 denier. Thereafter, using the cotton nonwoven fabric used in Example 1, after laminating the cotton nonwoven fabric and the fiber fleece,
A laminated nonwoven fabric having a basis weight of 60 g / m ² was obtained in the same manner as in Example 1. The properties of the laminated nonwoven fabric obtained as described above are
As shown in Table 1.

Comparative Example 3 A fiber assembly was obtained in the same manner as in Example 1 except that the basis weight of the fiber assembly was changed to 60 g / m ² . This fiber assembly was introduced into a hot embosser to obtain a fiber fleece having a basis weight of 60 g / m ² . The embossing roll provided in the hot embossing device had scattered convex portions at a ratio of 10% to the roll surface area, and the temperature was set to 125 ° C. Next, a split nonwoven fabric was obtained under the same conditions as in Example 1.
The characteristics of the split nonwoven fabric were as shown in Table 1.

Comparative Example 4 A cotton nonwoven fabric was obtained under the same conditions as in Example 1 except that the basis weight was 60 g / m ² . The characteristics of this cotton nonwoven fabric were as shown in Table 1.

As is clear from Table 1, Examples 1, 2 and
The laminated nonwoven fabrics obtained by the methods according to 3 and 4 are those in which a split nonwoven fabric composed of split fibers A and B and a cotton nonwoven fabric are firmly laminated and integrated, and have a high peel strength. there were. Further, it was excellent in mechanical properties such as tensile strength and tensile elongation, excellent in flexibility, and had good filter performance and water absorption.

On the other hand, the laminated nonwoven fabric obtained by the method according to Comparative Example 1 did not use split-split nonwoven fabric, but was a continuous core-sheath type two-component composite having polyethylene terephthalate as a core and polyethylene as a sheath. Since the fiber fleece formed of fibers was used, the fiber fleece and the cotton nonwoven fabric were not firmly integrated, and the peeling strength was poor.
Further, since no split fiber was used, the flexibility and the filter performance were poor. However, it was excellent in mechanical properties and water absorption. Since the laminated nonwoven fabric obtained by the method according to Comparative Example 2 also uses the fiber fleece formed of the monocomponent continuous fiber without using the splitting nonwoven fabric, similar to the case of Comparative Example 1, The peel strength was poor, and the flexibility and filter performance were poor.
And it was excellent in mechanical characteristics and water absorption.

The nonwoven fabric obtained by the method according to Comparative Example 3
It is composed of only split nonwoven fabric on which no cotton nonwoven fabric is laminated. Therefore, although excellent in mechanical properties, flexibility and filter performance, it was inferior in water absorption. The nonwoven fabric obtained by the method according to Comparative Example 4 was composed of only a cotton nonwoven fabric on which the split nonwoven fabric was not laminated. Therefore, although the water absorption performance was excellent, the mechanical properties and the filter performance were inferior.

[0058]

The laminated nonwoven fabric according to the present invention comprises a split nonwoven fabric and a cotton nonwoven fabric, and the split nonwoven fabric is composed of splitting fibers A having a high melting point and splitting fibers B having a low melting point. Then, at the interface between the two nonwoven fabrics, the cotton fibers in the cotton nonwoven fabric are embedded in the melted split fiber B. Therefore,
The split nonwoven fabric and the cotton nonwoven fabric are firmly integrated. In addition, since the split nonwoven fabric is formed of split fibers A and B having a small fineness, the split fibers have a low softness. Therefore,
The split nonwoven fabric or the laminated nonwoven fabric obtained by laminating the split nonwoven fabric with the cotton nonwoven fabric is rich in flexibility and excellent in filter performance. Furthermore, only split fiber B is melted,
Since the split fiber A is less likely to be softened or melted and melted, the air permeability is hardly reduced, and good filter performance is not hindered. Moreover, the cotton nonwoven fabric was rich in water absorption.

[0059]

The laminated nonwoven fabric according to the present invention exhibits the above-mentioned actions synergistically and comprehensively, has a high peel strength, is rich in flexibility, has good filter performance and good water absorption, and It has good mechanical properties. That is, according to the present invention, there is an effect that a nonwoven fabric having such characteristics can be obtained. Therefore, the laminated nonwoven fabric according to the present invention is suitably used for various uses such as medical / sanitary materials, clothing, living-related materials, and industrial use.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a cross section of a splittable bicomponent conjugate fiber used in the present invention.

FIG. 2 is a diagram showing an example of a cross section of a splittable bicomponent conjugate fiber used in the present invention.

FIG. 3 is a view showing an example of a cross section of a splittable bicomponent conjugate fiber used in the present invention.

FIG. 4 is a diagram showing an example of a cross section of a splittable bicomponent conjugate fiber used in the present invention.

FIG. 5 is a diagram schematically showing an example of a cross section of the laminated nonwoven fabric according to the present invention.

FIG. 6 schematically shows a cross section shown in FIG. 5 in which a fixing area (necking portion X) in which a split nonwoven fabric (hatched portion) and a cotton nonwoven fabric (white background portion) are bonded is enlarged. FIG.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-156557 (JP, A) JP-A-5-230751 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D04H 1/00-18/00

Claims (3)

(57) [Claims] 1. A fiber-forming polymer A, which is incompatible with the polymer A and has a melting point of from 30 to less than the melting point of the polymer A.
A split type bi-component conjugate fiber obtained by splitting a fiber-forming polymer B having a melting point of 180 ° C. lower with a fiber-forming polymer B is split and split so as to have a split rate of 60% or more. A split nonwoven fabric containing a split fiber A having a fineness of 0.05 to 0.8 denier and a split fiber B having a fineness of 0.05 to 2 denier composed of the polymer B; A laminated nonwoven fabric obtained by laminating a cotton nonwoven fabric in which the fibers are entangled with each other, wherein the cotton fibers located at least at the boundary surface between the split nonwoven fabric and the cotton nonwoven fabric are embedded in the melted split fiber B. by has been fixed fixed area in state has been stuck and the該割fiber nonwoven fabric and該綿nonwoven, the fixed area smell
Wherein the split fiber A is not substantially melted . 2. The laminated nonwoven fabric according to claim 1, wherein the area of the fixed area is 4 to 50% of the total area of the boundary surface between the split nonwoven fabric and the cotton nonwoven fabric. 3. A fiber-forming polymer A, which is incompatible with the polymer A and has a melting point of 30 to less than the melting point of the polymer A.
A split type bicomponent conjugated fiber in which a fiber-forming polymer B having a melting point of 180 ° C. lower is conjugated, is formed by splitting the split fiber so as to have a split rate of 60% or more, and is formed of the polymer A. Split non-woven fabric containing split fibers A having a fineness of 0.05 to 0.8 denier and split fibers B having a fineness of 0.05 to 2 denier composed of the polymer B; After laminating a cotton nonwoven fabric entangled with the fiber, the laminate is introduced into an ultrasonic fusing machine to soften or melt at least a part of the split fiber B, and to soften or melt the split fiber. during the fiber B is embedded a portion of該綿fibers, whereas,該割fiber fibers
A is a method for producing a laminated nonwoven fabric, wherein the nonwoven fabric is not substantially softened or melted .