WO2005095701A1

WO2005095701A1 - Process for producing nonwoven fabric and nonwoven fabric

Info

Publication number: WO2005095701A1
Application number: PCT/JP2005/005874
Authority: WO
Inventors: Toshiyuki Ogata; Shin Kasai; Hirofumi Yashiro; Akio Ohta
Original assignee: Ube Nitto Kasei Co., Ltd.
Priority date: 2004-03-30
Filing date: 2005-03-29
Publication date: 2005-10-13
Also published as: EP1739220A4; CN1926272A; EP1739220A1; US20080045109A1; JP2005281924A; JP4459680B2; CN100529225C; CA2561911A1

Abstract

A process for producing a nonwoven fabric, comprising the laminating step of laminating conjugate yarns in at least three directions of the warp direction, diagonal direction and reverse diagonal direction, the conjugate yarns obtained by bundling multiple resin monofilaments each having a sheath-core structure composed of a fibrous core resin surrounded by a sheath resin whose melting point is ≥ 20˚C lower than that of the core resin and effecting fusion bonding of the sheath resins; and the bonding step of heating the laminated filament bundles at temperature that is lower than the melting point of the core resin but higher than the melting point of the sheath resin so as to effect bonding thereof. Thus, there is provided a process for producing a nonwoven fabric excelling in flexibility and follow properties that is capable of regulating the strength, etc. thereof in conformity with the intended application field and demanded properties, and provided such a nonwoven fabric.

Description

Specification

Nonwoven fabric manufacturing method and nonwoven fabric

Technical field

The present invention relates to a method for producing a nonwoven fabric formed by laminating continuous fiber yarns and a nonwoven fabric formed by laminating continuous fiber yarns.

Background art

[0002] As industrial materials such as concrete spalling prevention materials, in addition to woven fabrics and knitted fabrics such as glass fiber, carbon fiber, aramid fiber, and vinylon fiber, various braided fabrics (registered trademark) (continuous fiber nonwoven fabric) are generally used. I have. The braid includes triaxial braids laminated in the warp, diagonal, and reverse diagonal directions, and four-axis braids laminated in the warp, weft, diagonal, and reverse diagonal directions.

[0003] As a manufacturing method of this braided fabric, for example, a manufacturing method is known in which vinylon fibers and the like are aligned in a predetermined direction, and the fibers are bonded to each other with a hot melt adhesive or emulsion adhesive. Also, there is a manufacturing method in which reinforcing fibers (glass fiber, carbon fiber, alumina fiber, aramide fiber, etc.) coated with thermoplastic resin are aligned and fused together (for example, see Patent Document 1). There is also known a production method in which a thermoplastic resin is adhered to a surface of the resin by bonding (for example, see Patent Document 2). Further, a mesh sheet is also known in which a polyester polymer is used for the core portion and a sheath portion is knitted and woven using a polyester-based core-sheath yarn having a lower melting point than the polyester polymer used for the core portion. For example, see Patent Document 3).

Patent Document 1: JP-A-11-20059

Patent document 2: WO00 / 21742

Patent Document 3: JP 2003-301346 A

Disclosure of the invention

Problems to be solved by the invention

[0004] However, in a manufacturing method in which vinylon fibers are assembled and then bonded with a hot-melt adhesive or emulsion adhesive, an adhesive is required, which increases the cost, and the adhesive also adheres to unnecessary parts. However, there is a problem that the working environment of the nonwoven fabric manufacturing process is inferior. [0005] Furthermore, in the method of fusing reinforcing fibers using a thermoplastic resin, it is difficult to completely cover the reinforcing fibers with the thermoplastic resin, so that the adhesive strength is insufficient, and as a result, The durability is not sufficient, especially when applied to long-term applications such as cleat separation prevention.

[0006] On the other hand, in a mesh sheet knitted and woven using a core-sheath structured yarn of a polyester-based polymer, the gap between the fibers cannot be increased as in the case of yarn and cloth. There are problems that it is difficult to apply and that the production of the mesh body is troublesome and costly.

[0007] Furthermore, both the braid and the mesh sheet of the above disclosed examples are inferior in flexibility and bendability and do not have sufficient followability. Such yarns and mesh sheets are inferior in general versatility in the field of industrial materials such as concrete spalling prevention.

[0008] Therefore, the present invention provides a nonwoven fabric comprising a continuous fiber having excellent flexibility and flexibility, excellent followability, and whose strength and flexibility can be adjusted according to the intended use and required characteristics. It is an object of the present invention to provide a method for producing the same. Another object of the present invention is to provide a nonwoven fabric made of continuous fiber obtained by this production method.

Means for solving the problem

[0009] In order to achieve the above object, the method for producing a nonwoven fabric of the present invention has a core-sheath structure in which a fibrous core resin is surrounded by a resin having a melting point of 20 ° C or more and a lower melting point. A laminating step of bundling a plurality of fat monofilaments and laminating a composite yarn obtained by fusing the sheath with the fat in at least three directions of a warp direction, a diagonal direction, and a reverse diagonal direction; A bonding step of bonding by heating at a temperature lower than the melting point of the resin and higher than the melting point of the sheath resin.

[0010] The composite yarn in the method for producing a nonwoven fabric of the present invention has excellent flexibility and strength because the sheath resin is fused, and furthermore, the resin single fiber does not disperse. In addition, it is possible to produce a nonwoven fabric having excellent flexibility and strength with less trouble in nonwoven fabric production. In addition, since the sheath resin of the core-sheath structure has a melting point lower than that of the core resin by 20 ° C. or more, after laminating the composite yarns in each direction in the nonwoven fabric manufacturing method of the present invention, the melting point of the core resin is reduced. When heating at a lower temperature than the melting point of the sheath resin, only the sheath resin is melted without melting the core resin and the composite yarns can be bonded to each other. That is, the nonwoven fabric of the present invention can be manufactured without using an adhesive such as a hot melt resin or a thermoplastic resin. In addition, since the difference in melting point is 20 ° C or more, the core resin becomes difficult to melt even when the sheath resin is melted, and the core resin maintains a fibrous form. It is possible to prevent the composite yarn from being deformed during the production of the nonwoven fabric. That is, since the deformation or cutting of the composite yarn, which is likely to occur when using a resin monofilament having no core-sheath structure, can be prevented, the production trouble is further reduced.

[0011] Further, since the composite yarns are laminated in at least three directions of the warp direction, the oblique direction, and the reverse oblique direction, a nonwoven fabric having excellent strength can be manufactured regardless of the direction.

[0012] The composite yarn in the method for producing a nonwoven fabric of the present invention also has a resin monofilament strength of 10 to 500 fibers. In the composite yarn, the core resin has a fibrous island portion having a fineness of l to 70 dtex. It is preferable that the sheath resin that forms (island part resin) and the fused sheath part forms sea part (sea part resin)! Since such a composite yarn is in the form of a fiber-reinforced thermoplastic resin, it has strength and rigidity in the longitudinal (fiber axis) direction. Can be further improved. Further, by adjusting the sectional diameter of the island resin and the number of bundles, the strength and flexibility can be made favorable, and the followability can be further improved.

[0013] Further, in the method for producing a nonwoven fabric of the present invention, the core resin and the sheath resin in the resin core fiber having a core-sheath structure are preferably polyolefin. By using polyolefin as the core resin, flexibility and workability are improved. In addition, when both the core resin and the sheath resin are polyolefin, the affinity of the core resin and the sheath resin is excellent. The composite yarn structure in which the core is a reinforcing fiber and the sheath is a matrix resin can be maintained without being separated from polyolefin, which is a fat. In addition, since polyolefin is non-polar, it can withstand acids and bases, and can produce a nonwoven fabric with excellent durability.

[0014] The core resin is preferably polypropylene, and the sheath resin is preferably polyethylene having a melting point of 120 ° C or lower. The nonwoven fabric of such a configuration has the properties of the composite yarn and Together, they have particularly excellent flexibility and bendability and have excellent followability. In other words, when the conventional braid is used to cover a bent portion, it is inferior in flexibility and bendability and rebounds due to the elasticity of the braid, which makes it difficult to cover the corners. However, the nonwoven fabric of the present invention can be easily bent, and can be adhered to and adhere to an object.

[0015] If the core resin is polypropylene, the melting point is relatively high, so that separation or decomposition by heat, acid, or a base can be prevented. Therefore, the shape of the nonwoven fabric can be maintained even after long-term use. Furthermore, since polypropylene is a thermoplastic resin, it can be recycled and is environmentally friendly.

[0016] In addition, if the sheath resin is polyethylene, the melting point is relatively low, so that the sheath resin can be easily melted. Energy loss.

[0017] The nonwoven fabric of the present invention is a composite yarn (10 to 500 fibrous island resins having a fineness of l to 70 dtex) arranged in a fibrous sea resin (in the longitudinal direction of the fibrous sea resin). (It is preferable that fibrous island resin is arranged along the same direction) in at least three directions: longitudinal, diagonal, and reverse diagonal, and marine resin is melted and laminated. It is a nonwoven fabric in which yarns are bonded to each other, wherein the sea part resin has a melting point lower than the island part resin by 20 ° C or more. Since such a composite yarn is excellent in flexibility, a trouble in production of the nonwoven fabric is reduced, and a nonwoven fabric excellent in flexibility and strength can be obtained.

[0018] The method for producing a composite yarn in the nonwoven fabric of the present invention can be obtained by any of the following methods. That is,

(1) Core and sheath monofilaments are bundled and stretched at a temperature lower than the melting point of the core resin and higher than the melting point of the sheath resin to melt the sheath resin and fuse the sheath resin with each other. In this method, seawater resin (matrix) is composed and the core resin is island-water resin (reinforcement fiber) to form a sea-island composite yarn.

(2) In a state where the drawn fibers of the core-sheath structure are aligned, while heating at a temperature lower than the melting point of the core, which is higher than the melting point of the sheath, and passing through a die having a predetermined diameter, the sheaths are heated. How to fuse (3) A method of drawing an undrawn yarn having a sea-island structure comprising an island resin and a sea resin having a melting point lower than that of the island resin by 20 ° C or more.

In order to obtain a composite yarn having better flexibility and strength, the above-mentioned (1) or (2)

U), especially the method (1) is preferred.

In the nonwoven fabric of the present invention, the sea-island composite yarn is preferably a sea-based resin and an island-based resin are polyolefins. Furthermore, the sea-based resin is polypropylene and the island-based resin has a melting point of 120. U, which is preferably polyethylene below ° C.

[0020] In the nonwoven fabric of the present invention, the mass ratio of island resin to sea resin in the composite yarn is 2

It is preferably 0:80 to 80:20. With such a mass ratio, strength and flexibility can be appropriately adjusted.

The invention's effect

According to the method for producing a nonwoven fabric of the present invention, it is possible to produce a nonwoven fabric which is excellent in flexibility and followability, and whose strength and flexibility can be adjusted according to the intended use and required properties. it can. In addition, the nonwoven fabric obtained by this manufacturing method is useful as a material for preventing concrete from falling off, a net for protecting riverbeds, a net for preventing the outflow of cultured shellfish, a net for controlling pests, and a casing material for filters.

Brief Description of Drawings

FIG. 1 is a plan view showing a nonwoven fabric according to an embodiment.

FIG. 2 is an enlarged perspective view of a portion P in FIG. 1.

FIG. 3 is a perspective view showing a bundled resin single fiber.

FIG. 4 is a perspective view showing a composite yarn that can be used for the nonwoven fabric of the present invention.

FIG. 5 is a plan view showing a positional relationship between a contact surface between a warp 11 and an oblique yarn 12 of the nonwoven fabric shown in FIG. 1 and a reverse oblique yarn 13.

FIG. 6 is a plan view showing an embodiment of a positional relationship between a contact surface between the warp yarn 11 and the diagonal yarn 12 and the reverse diagonal yarn 13 of the nonwoven fabric according to the present invention.

FIG. 7 is a plan view showing a drum and a traverser in a state where a warp group and a weft group are fed.

FIG. 8 is a front view showing a drum, a traverser, and a weft feeding mechanism. FIG. 9 is a plan view showing a nonwoven fabric according to another embodiment.

Explanation of symbols

[0023] 10, 40 · · · non-woven fabric, 11 · · warp, 12 · · · oblique yarn, 13 · · · reverse oblique yarn, 20a ... resin single fiber bundle, 20b ... composite yarn, 21a ... core Resin, 21b ... island resin, 22a ... sheath resin, 22b ... sea resin, 23a ... resin monofilament, 30 ... nonwoven fabric manufacturing equipment, 31 ... drum, 32 ... rotating shaft, 33a, 33b: thread hooking device, 34: traverser, 35: weft feeding mechanism, 36: through-hole, H: contact surface, Τ1 · · · warp group, T2: weft group, Τ3 · · oblique yarn group.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing a nonwoven fabric according to the embodiment.

[0025] The nonwoven fabric 10 shown in FIG. A plurality of reverse oblique yarns 13 are arranged in parallel, and a force is also formed. Here, the warp yarn 11, the oblique yarn 12 and the reverse oblique yarn 13 are all composite yarns, and are the same except that the aligned directions are different. Further, the warp 11, the oblique thread 12 and the reverse oblique thread 13 are all arranged at equal intervals, and the contact surface of the warp 11 and the oblique thread 12 is located on the reverse oblique thread 13.

FIG. 2 is an enlarged perspective view of a portion where the warp 11, the oblique yarn 12 and the reverse oblique yarn 13 intersect (region P in FIG. 1). As shown in FIG. 2, the warp yarn 11, the oblique yarn 12, and the reverse oblique yarn 13 according to the embodiment have an oval cross-sectional shape. The warp yarn 11 is adhered to the oblique yarn 12 at the contact surface H, and the reverse oblique yarn 13 is adhered to the oblique yarn 12 at the surface opposite to the contact surface H. In addition, the contact surface H between the warp yarn 11 and the oblique yarn 12 and the contact surface between the oblique yarn 12 and the reverse oblique yarn 13 have the sheath resin melted and adhered.

FIG. 3 is a perspective view showing a bundle of resin single fibers (hereinafter referred to as a “resin single fiber bundle” t). The resin single fiber bundle 20a shown in FIG. 3 is obtained by, for example, bundling resin single fibers in an undrawn state. That is, the resin single fiber bundle 20a is formed by bundling a plurality of resin single fibers 23a having a core-sheath structure including a core resin 21a and a sheath resin 22a.

FIG. 4 is a perspective view showing a composite yarn according to the present invention. The composite yarn 20b is, for example, an undrawn resin single fiber bundle 20a obtained by bundling a plurality of resin single fibers 23a having a core-sheath structure shown in FIG. The sheath resin is melted while being stretched, and the sheath resin is fused together to form a sea-island structure with a substantially elliptical cross-sectional shape.

That is, in the composite yarn 20b, as shown in FIG. 4, the core resin 21a forms the island resin 21b, and the sheath resin 22a fuses to form the sea resin 22b. . As a result, a sea-island structure is formed as a whole. The composite yarn 20b thus obtained is most suitable as a composite yarn for obtaining the nonwoven fabric 10 in terms of strength and flexibility.

5 and 6 are plan views showing the positional relationship between the contact surface between the warp yarn 11 and the oblique yarn 12 and the reverse oblique yarn 13. FIG. In FIG. 5, the contact surface between the warp yarn 11 and the oblique yarn 12 is on the reverse oblique yarn 13, and the nonwoven fabric 10 shown in FIG. 1 has such a positional relationship. On the other hand, in FIG. 6, the contact surface of the warp yarn 11 and the oblique yarn 12 does not exist on the reverse oblique yarn 13, and the warp 11 and the oblique yarn 12, the warp 11 and the reverse oblique yarn 13, the oblique yarn The yarn 12 and the reverse oblique yarn 13 are bonded to each other. At least a part of the nonwoven fabric according to the present invention may have such a positional relationship.

[0031] Since the nonwoven fabric 10 has the fiber bundles laminated in the warp direction, the oblique direction, and the reverse oblique direction, the nonwoven fabric 10 has excellent strength regardless of the direction. Further, as shown in FIG. 1, the arrangement of the warp yarns 11, the oblique yarns 12, and the reverse oblique yarns 13 are all equidistant, and thus the nonwoven fabric 10 has excellent strength and excellent balance. Furthermore, since each fiber bundle forms an equilateral triangle by intersecting, the nonwoven fabric 10 is also excellent in design.

[0032] It should be noted that the above fiber bundles need not necessarily be at equal intervals. The non-woven fabric 10 can obtain desired flexibility and strength by adjusting the intervals between the warp yarns 11, the diagonal yarns 12, or the reverse diagonal yarns 13, and can reduce the size of the gap between the respective fiber bundles. It can also be adjusted. Therefore, the required characteristics can be imparted according to the use mode and purpose.

As described above, the nonwoven fabric 10 is excellent in strength and followability, so that it can be suitably used in the field of industrial materials. In particular, since the gap between the fiber bundles can be adjusted, for example, when used as a concrete spalling prevention material, if the gap between the fiber bundles is large to some extent, it will have excellent integrity with concrete and high spalling prevention performance. Can be demonstrated.

[0034] Furthermore, since the nonwoven fabric 10 does not require a hot melt adhesive or a thermoplastic resin or the like for production, the step of applying the hot melt adhesive, the thermoplastic resin, or the like can be omitted. It can increase the speed. Further, the non-woven fabric 10 is composed of a warp 11, an oblique yarn 12, and a reverse oblique. Since the interlaced yarn 13 can be bonded by laminating and heating, it can be manufactured relatively easily. That is, mass production is easy and the productivity is excellent.

As shown in FIG. 4, since the composite yarn 20b has a sea-island structure, the marine resin 22b is melted when the nonwoven fabric 10 is manufactured, and is fused with the marine resin 22b of the adjacent composite yarn 20b. Glue. Therefore, the nonwoven fabric 10 exhibits high strength as a whole.

[0036] The core resin 21a needs to have a melting point higher by 20 ° C or more than the sheath resin 22a. If the difference in melting point is 20 ° C or more, the core resin becomes difficult to melt even when the sheath resin is melted, and the shape of the composite yarn can be maintained while maintaining the strength of the core fiber. . Therefore, the difference between the melting points is preferably large, more preferably 40 ° C. or more!

In the present embodiment, the core resin 21a also has a polypropylene force, and the sheath resin 22a also has a polyethylene force. When the sheath resin 22a is made of polyethylene, polyethylene is thermoplastic and has a relatively low melting point, so that it can be efficiently melted and bonded when heated. In addition, if the core resin 21a is made of polypropylene, the melting point of polypropylene is relatively high, so that it has excellent thermal stability even when used for a long time, and since it is non-polar, it is difficult to separate or decompose with acids or bases. It has excellent durability. Furthermore, after use, it can be easily recycled by melting and reshaping. Therefore, it is environmentally friendly because it does not become industrial waste and has excellent safety.

[0038] In addition, by adopting the above structure using polypropylene and polyethylene, it is possible to narrow the gap between the respective composite yarns or to use a composite yarn in which the number of resin monofilaments having a core-sheath structure is increased. Even when the strength of the nonwoven fabric is increased, it is specifically excellent in flexibility and easily bends. Therefore, even when the nonwoven fabric having such a configuration is used to cover a bent portion or a curved portion, the nonwoven fabric can be covered in close contact with an object.

In the present invention, the polyethylene used is preferably a low-density polyethylene, and more preferably has a melting point of 120 ° C. or less. Since low-density polyethylene has a low melting point, bonding can be performed at a particularly low temperature, and processing efficiency is dramatically improved.

[0040] The fineness of the polypropylene which is the island part resin 21b is preferably 1 to 70 dtex, more preferably 2 to 50 dtex. 30dtex or less especially when flexibility is required Is preferred. If the fineness is less than ldtex, the island resin 21b becomes too thin, so that it is difficult to maintain the shape, and the physical properties after thermal bonding tend to be reduced. On the other hand, when the fineness exceeds 70 dte X, the resin single fiber 23a itself becomes too thick, so that flexibility and flexibility are impaired.

Further, the composite yarn can be produced by stretching a plurality of resin single fibers 23a while being bundled. In this case, the number of bundles is preferably 10 to 500. If the number is less than 10, the resin monofilament 23a becomes thick and spinnability may be deteriorated. If the number is more than 500, the spinning nozzle density increases and the resin monofilament 23a becomes thin, so that spinning is performed. And stretchability may be poor. More preferably, the number is 100 to 300.

[0042] The fineness of the composite yarn 20b is preferably 100 to 5000 dtex. If it is less than lOOdtex, it will be difficult to obtain the desired physical properties, and if it exceeds 5000dtex, the flexibility and followability may be impaired. More preferably, it is 500-3000 dtex

[0043] The nonwoven fabric according to the present invention preferably has a mass ratio of the island resin 21b to the sea resin 22b of 20:80 to 80:20. If the mass ratio of the island resin 21b to the sea resin 22b is less than 20%, it may be difficult to obtain desired physical properties, and the mass ratio of the island resin 21b to the sea resin 22b may be reduced. If the ratio exceeds 80%, the thermal adhesive strength may be reduced. More preferably, it is 40:60 to 70:30.

[0044] The nonwoven fabric 10 can be manufactured using a nonwoven fabric manufacturing apparatus. FIG. 7 is a plan view of a manufacturing apparatus capable of manufacturing the nonwoven fabric 10, and FIG. 8 is a front view thereof.

The nonwoven fabric manufacturing apparatus 30 shown in FIGS. 7 and 8 includes a drum 31 having a circular cross section, a traverser 34, and a weft feeding mechanism 35. The drum 31 rotates counterclockwise in the figure around a rotation axis 32 parallel to the y direction. The traverser 34 reciprocates in the y-direction along the side surface of the drum 31 and forms an oblique thread group T3 on the warp group T1 supplied to the drum 31. The weft feeding mechanism 35 feeds the weft group T2 for forming the diagonal yarn group T3 to the traverser 34.

When the nonwoven fabric 10 is manufactured using the nonwoven fabric manufacturing apparatus 30, first, a warp group T1 in which a plurality of warps 11 are arranged in parallel in a warp direction (X direction in the figure) is formed on a side surface of a cylindrical drum 31. Along the circumference, it is supplied so as to wind in a circumferential direction. The drum 31 is rotatable about an axis 32. It is supported by a table (not shown) and rotates at a constant speed with respect to the base. On the circumference of the edge of the drum 31, a thread hook 33a is provided, and on the circumference of the other edge, a thread hook 33b is provided so as to protrude vertically to the cylindrical side surface. It is arranged to separate. The traverser 34 is provided in an arc shape along the side surface of the drum 31 and is supported along the side surface of the drum 31 so as to reciprocate in the Y direction. The traverser 34 has a through-hole 36 through which each of the weft group T2 sent from the weft sending mechanism 35 passes. The weft group T2 is sent from the weft feed mechanism 35 to the drum 31 via the through hole 36, and reciprocates on both edges of the drum 31 while being alternately hooked between the yarn hooks 33a and 33b. On the warp group T1 sent on the side surface of the drum 31, a plurality of diagonal yarns 12 and reverse diagonal yarns 13 are stretched as a diagonal yarn group T3 arranged in parallel.

[0047] In this way, the nonwoven fabric 10 is formed by the oblique thread group T3 which is obliquely stretched on the warp group T1. The reciprocating pitch of the traverser 34 is controlled so as to have a predetermined ratio with respect to the rotation pitch of the drum 31. The ratio between the reciprocating pitch of the traverser 34 and the rotation pitch of the drum 31 may be controlled directly in a mechanically linked manner or indirectly by a servomotor.

[0048] In a wide variety of fields of industrial materials, a nonwoven fabric having higher strength may be required. In that case, the strength can be increased by increasing the density of the yarn and cloth as described above. That is, the number of the warp yarns 11 in the warp group T1 in which a plurality of warp yarns 11 are arranged in parallel in the warp direction (the X direction in the drawing) or the yarn hooks 33a provided on the circumference of the edge of the drum 31 and By reducing the interval of 33b, it is possible to provide a high density nonwoven fabric

[0049] In the method for producing a nonwoven fabric according to the present invention, composite yarns aligned in the warp direction, the oblique direction, and the reverse oblique direction are bonded by heating. The heating temperature is lower than the melting point of the core resin and higher than the melting point of the sheath resin. When heat treatment is performed at this temperature, only the sheath resin can be melted and bonded without melting the core resin of the core-sheath structure, and the strength of the entire nonwoven fabric can be improved. Heating for melting the sheath resin is preferably contact heating using a heating roller or the like.

[0050] In addition to heat treatment, pressurization such as cylinder pressurization, air pressurization, and pressurization by its own weight. Preferably, a treatment is also performed. By performing the pressure treatment, the area of the contact surface of the composite yarn becomes large, the adhesive force of the contact surface becomes strong, and at the same time, the thickness of the nonwoven fabric can be adjusted.

[0051] Further, it is more preferable that the nonwoven fabric according to the present invention be pressurized in a heated state.

Heating melts the marine resin of the composite yarn and adheres to the marine resin of other composite yarns.However, if pressure is applied in a heated state, the composite yarn is crushed and the composite yarn is bonded to another composite yarn. The surface becomes even larger. Therefore, when pressure is applied simultaneously with heating, stronger adhesion can be exhibited. If the above-mentioned pressure contact is made with the drum 31, the heating calo-pressure treatment can be performed at once, and the workability is improved.

As described above, the force described in the embodiment of the method for manufacturing a nonwoven fabric according to the present invention is not necessarily limited to the above-described embodiment, and various modifications can be made.

For example, after the resin single fiber bundle 23a is formed into the composite yarn 20b, it is also possible to divert crimping or false twisting techniques for the purpose of imparting flexibility to the composite yarn. By diverting the crimping and false twisting techniques, the flexibility of the fiber is improved and the workability of the nonwoven fabric is improved.

[0054] The nonwoven fabric 10 according to the embodiment of the present invention is a triaxial fabric in which composite yarns are laminated in the warp direction, the oblique direction, and the reverse oblique direction. In this case, the crossing angle between the warp 11 and the oblique yarn 12 or the reverse oblique yarn 13 is preferably 60 ± 10 °.

[0055] Further, the composite yarn can be knitted on the triaxial fabric in the weft direction. That is, a four-axis fabric in which composite yarns are laminated in the warp direction, the weft direction, the oblique direction, and the reverse oblique direction can be used. In this case, the weft is orthogonal to the warp direction. In the case of a four-axis fabric, the crossing angle between the warp or weft and the diagonal or reverse diagonal is preferably 45 ± 10 °. A four-axis fabric is excellent in strength, and even when twisted.

In the present embodiment, the core resin 21a is made of polypropylene, and the sheath resin 22a is made of polyethylene. Resin. Specifically, polyethylene terephthalate and polyamide (nylon) are used as the core resin 21a, and resins having a lower melting point and various copolymer resins are used as the sheath resin 22a. In particular, when the nonwoven fabric of the present invention is used as a cement-based reinforcing material, it is preferable to use polyolefin, which is preferably an alkali-resistant thermoplastic resin for the core resin 21a and the sheath resin 22a. More preferred. Core resin 21a with polyolefin By doing so, followability and workability are improved. When the core resin 21a and the sheath resin 22a are both polyolefins, the affinity of the core resin 21a and the sheath resin 22a is excellent. In addition, the core resin 2 la, polyolefin, can maintain the core-sheath structure without separation. In addition, since polyolefin is non-polar, it is possible to produce a nonwoven fabric that is resistant to acids and bases and has excellent durability.

FIG. 9 is a plan view showing a nonwoven fabric 40 according to another embodiment. The nonwoven fabric 40 includes a plurality of warp yarns 11 arranged in parallel in the warp direction, a plurality of diagonal yarns 12 arranged diagonally to the warp yarns 11, and a plurality of reverse oblique lines arranged diagonally to the warp yarns 11 and the diagonal yarns 12. Thread 13 and power are also composed! Here, the warp yarns 11 are alternately bonded to one side and the other side of the contact surface of the oblique yarn 12 and the reverse oblique yarn 13.

[0058] The nonwoven fabric 40 having such a structure is particularly excellent in strength and also excellent in strength when twisted. In addition, when used as a concrete spalling prevention material, it exhibits high strength regardless of the shape of the concrete, and is particularly excellent in durability and useful.

[0059] Further, the method for manufacturing the nonwoven fabric 40 is such that the warp 11 is drawn and adhered only to one surface of the contact surface of the oblique yarn 12 and the reverse oblique yarn 13, and then the warp 11 is drawn and adhered to the other surface. It is manufactured by

Example

[0060] <Production of composite yarn>

Using isotactic polypropylene with MFR = 20 (g / min) as the thermoplastic resin for the core resin, and low density MI (190 ° C) = 20 (g / min) as the sheath resin Polyethylene resin was used. Spinning was carried out using a conventional composite spinning facility, core-sheath type composite spinning nozzle (150H). The obtained 150 resin monofilaments were bundled, passed through a drawing equipment directly connected thereto, and subjected to roller drawing at a total draw ratio of 14 times under a saturated steam pressure of 4.2 kPa (145 ° C) absolute pressure. Immediately through a molding die of a predetermined shape, a) An approximately elliptical composite yarn (Island) in which polypropylene fiber (melting point 165 ° C) of Shima resin is bound with low-density polyethylene (melting point 113 ° C) of Shima resin. The mass ratio of part resin to sea part resin was 55:45).

The obtained composite yarn was 2200 dtex, the single fiber diameter of the island part resin was 33., and the strength was 6.0. cNZdtex.

The obtained composite yarn was used as a warp and a weft, and the warp, the diagonal yarn, and the reverse diagonal yarn were laminated at a pitch of 9 mm using the manufacturing apparatus shown in FIGS. At that time, the warp yarns were alternately arranged in the upper and lower layers, and the diagonal yarns and the reverse diagonal yarns were laminated so as to be located in the intermediate layer. Then, the nonwoven fabric A was obtained by contact heating with a heating roller having a surface temperature of 150 ° C. to melt the marine resin of the composite yarn and adhere the composite yarn of each layer.

(Comparative Example)

2,000 dtex (750 filament filaments) vinylon fiber yarns were used as warp yarns, diagonal yarns, and reverse diagonal yarns, each of which was laminated at the same pitch as in the examples. Next, the nonwoven fabric B was impregnated with an acrylic adhesive and heated by contact with a heating roller having a surface temperature of 150 ° C. to obtain a nonwoven fabric B having an adhesive amount of 20% by weight based on the vinylon fiber yarn.

A test was conducted on the followability of the nonwoven fabrics A and B when bent. The non-woven fabric A of the example had a fold that was easy to be folded, and the folded shape was maintained as it was.The non-woven fabric B of the comparative example had a strong repulsive force to return to the original shape where the fold was difficult to be formed. It was difficult to maintain the shape.

JIS standard R3420 Glass fiber general test method 7.4 (a) Tensile strength was measured according to the test method of tensile strength of woven fabric. The tensile strength in the warp direction (warp direction) of a test piece having a width of 25 mm and the tensile strength in the direction perpendicular to the warp direction (weft direction) of a test piece having a width of 50 mm were measured. Is 370 NZ25 mm in the warp direction and 37 NZ50 mm in the weft direction, and the nonwoven fabric B of the comparative example was 480 NZ25 mm in the warp direction and 23 NZ50 mm in the weft direction o

[0065] It is considered that the tensile strength in the warp direction is due to the material of the warp, and the tensile strength in the weft direction is due to the difference in the adhesive force between the yarns. Therefore, the nonwoven fabric A of the example has a lower strength than the nonwoven fabric B of the comparative example in terms of material, and has a higher strength in terms of adhesive strength. You In other words, since the nonwoven fabric A of the example has tightly bonded composite yarns, it is particularly likely that the nonwoven fabric A has excellent adhesion in the weft direction, has improved strength, and has excellent followability.

Industrial applicability

The nonwoven fabric of the present invention has excellent flexibility and bendability, has excellent followability, and is capable of adjusting the strength and flexibility according to the intended use and required characteristics, so that the concrete can be prevented from peeling off. It can be applied particularly as an industrial material such as a material.

Claims

The scope of the claims

[1] A plurality of resin monofilaments having a core-sheath structure in which a fibrous core resin is surrounded by a sheath resin having a melting point of 20 ° C. or lower than this are bundled, and the sheath resin is condensed. A laminating step of laminating the composite yarn obtained by fusing in at least three directions of a warp direction, a diagonal direction, and a reverse diagonal direction; and the laminating composite yarns having a melting point lower than the melting point of the core resin and the sheath resin. And a bonding step of bonding by heating at a temperature higher than the melting point of the nonwoven fabric.

[2] The composite yarn also has a strength of 10 to 500 pieces of the resin monofilament, and in the composite yarn, the core resin forms a fibrous island portion having a fineness of l to 70 dtex, The method for producing a nonwoven fabric according to claim 1, wherein the fused sheath resin forms a sea part.

3. The method for producing a nonwoven fabric according to claim 1, wherein the core resin and the sheath resin are polyolefins.

[4] The method for producing a nonwoven fabric according to any one of claims 1 to 3, wherein the core resin is polypropylene, and the sheath resin is polyethylene having a melting point of 120 ° C or lower.

[5] A fibrous island resin with a fineness of l to 70 dtex is laid out in a fibrous marine resin with 10 to 500 fibers in at least three directions: warp, diagonal, and reverse diagonal. What is claimed is: 1. A nonwoven fabric obtained by laminating and bonding two or more composite yarns by melting and laminating a sea resin, wherein the sea resin has a melting point lower than that of the island resin by 20 ° C. or more.

6. The nonwoven fabric according to claim 5, wherein the island resin and the sea resin are polyolefin.

7. The nonwoven fabric according to claim 5, wherein the island resin is polypropylene, and the sea resin is polyethylene having a melting point of 120 ° C. or less.

[8] The nonwoven fabric according to any one of claims 5 to 7, wherein the mass specific force between the island resin and the sea resin is 20:80 to 80:20.