JP6282903B2 - Monofilament - Google Patents

Description

  The present invention relates to a monofilament, and particularly to a monofilament excellent in adhesiveness with a polyolefin resin.

  In recent years, with the spread of the Internet and an increase in video distribution, etc., it has been required to distribute a huge amount of information and increase the speed, and there is a demand for optical fibers that are excellent in speed and stability among transmission media. It is expanding. Various optical cables are used in order to draw optical fibers from an optical cable installed in the imaginary into an office or a general household.

  An optical cable stores a delicate optical fiber and needs to be devised so that it can withstand practical use indoors and outdoors. In general, in order to increase toughness, it is made up of an optical fiber, a sheath material, and a tension member, and is an optical cable that is less susceptible to external forces, has stable transmission characteristics, and is easy to install. It is required to do.

  The tension member used for the optical cable is mainly for protecting and reinforcing the optical fiber from the tension applied during laying. Conventionally, steel and glass fiber have been widely used. However, a tension member using steel has a problem of electromagnetic induction, a problem that a specific gravity is large and a fiber becomes heavy, and a tension member using glass fiber has a problem in impact resistance and flexibility of the material.

  Tension members using ceramic fibers, carbon fibers, aromatic polyester fibers, aramid fibers, polybenzazole fibers, and the like have also been proposed (see, for example, Patent Document 1 and Patent Document 2). However, since both are rigid, they are poor in flexibility, are inferior in workability when producing an optical cable, may damage the optical cable, and are inferior in handleability in laying work.

  Therefore, in Patent Document 3, a monofilament made of polyethylene naphthalate has been proposed as a material having a high Young's modulus and a high hook strength and excellent workability and handling at the time of processing when used in an optical cable. . According to this monofilament, strength and flexibility were provided, but adhesion to the sheath material constituting the cable was not considered. That is, there are various types of optical cables, but the optical fiber and the tension member are usually melt-coated with a sheath material that is an insulator. Therefore, when the adhesiveness with the sheath material is not taken into consideration, there is a problem that the tension member is detached from the cable (sheath material) and the optical fiber cannot be sufficiently protected.

  In patent document 4, the tension member which improved the adhesiveness with a sheath material is proposed by making the cross-sectional shape of a polyester monofilament into the unusual cross-sectional shape which has 1-30 protrusion in an outer periphery. However, such an irregular cross-sectional shape alone does not sufficiently improve the adhesiveness, and the irregular cross-sectional shape reduces the strength and cannot sufficiently protect the optical fiber.

  The applicant proposed a tension member that improved the adhesion to the sheath material by coating the surface of a monofilament made of polyamide resin containing layered silicate with a polyolefin resin aqueous dispersion to form a polyolefin resin layer. (Patent Document 5). However, although the adhesion between the monofilament and the sheath material is improved, there is a problem that the production process is not good because a process of coating the monofilament with a polyolefin resin and a process of heat treatment are necessary.

JP-A-8-21935 JP-A-9-251123 JP 2003-268626 A JP 2006-200073 A JP 2010-097060 A

  Reinforcement material for cables and cords in which polyolefin resin is used as a sheath material, for example, a monofilament that can be suitably used as a tension member provided with an optical fiber in an optical cable, and a reinforcement material (tension member) for cables and cords It is an object of the present invention to provide a monofilament that is excellent in adhesiveness with a polyolefin resin and has sufficient strength and flexibility.

As a result of investigations to solve the above problems, the present inventors have reached the present invention.
That is, in the present invention, the filament surface is constituted by a blended body obtained by blending an acid-modified polyolefin resin having a carboxylic anhydride group and a polyamide resin, and the filament has a strength of 150 N or more and a dry heat shrinkage rate. The gist of the present invention is a monofilament characterized by a content of 3% or less.

  Hereinafter, the present invention will be described in detail.

  First, the present invention is a monofilament yarn used by a single filament (in the present invention, “monofilament” is also referred to as “monofilament” by omitting the “filament” of the monofilament yarn), and is composed of a plurality of filaments. It is not a multifilament yarn. In the multifilament yarn, a plurality of filaments are converged to obtain a yarn. At this time, it is necessary to twist or apply an adhesive, which increases the number of steps and the cost. In the present invention, the process is simplified and the cost is reduced by using a monofilament.

  In the monofilament of the present invention, the filament surface is constituted by a blended body obtained by blending an acid-modified polyolefin resin having a carboxylic anhydride group and a polyamide resin.

  The blend placed on the filament surface is a blend of two types of thermoplastic resins, a specific acid-modified polyolefin resin and a polyamide resin. Examples of the polyolefin resin include polypropylene and polyethylene. In general, a polyolefin resin and a polyamide resin do not mix well even if they are blended because of poor compatibility. In the present invention, by adopting a specific acid-modified polyolefin-based resin called an acid-modified polyolefin-based resin having a carboxylic anhydride group, a blend body that can improve the compatibility with the polyamide-based resin and form a fiber is obtained. Can be obtained.

  Further, by providing a blend body containing such a specific acid-modified polyolefin resin on the filament surface, adhesion and bonding properties with a sheath material made of the polyolefin resin are improved. Therefore, when the monofilament of the present invention is used as a tension member, the adhesive member and the bondability with the sheath material are good, and the trouble that the tension member falls off from the cable does not occur.

  The blend ratio of the acid-modified polyolefin resin having a carboxylic anhydride group and the polyamide resin is preferably such that the acid-modified polyolefin resin is blended by at least 2.5% by mass or more, and the upper limit thereof is preferably 20% by mass. When the blend ratio of the acid-modified polyolefin resin is small, the adhesion / bondability with the sheath material tends to be inferior. If the blend ratio of the acid-modified polyolefin resin becomes too large, the filament strength tends to decrease. Further, the spinning operability when producing the monofilament tends to be inferior. A more preferable range of the blend ratio is 5% by mass to 10% by mass of the acid-modified polyolefin resin.

  More specifically, the acid-modified polyolefin resin having a carboxylic anhydride group used in the present invention is selected from the group consisting of propylene 75 to 99.9 mol%, ethylene and an α-olefin having 4 to 12 carbon atoms. Acid-modified polyolefin system having a carboxylic acid anhydride group comprising an esterified product of an acid-modified polyolefin having 0.1 to 25 mol% of at least one olefin as a structural unit and an aromatic ring-containing alcohol having 7 to 24 carbon atoms Resin can be used. As such an acid-modified polyolefin resin, an acid-modified low molecular weight polyolefin resin (trade name “YUMEX”) commercially available from Sanyo Chemical Industries may be used.

  Examples of polyamide resins to be blended with acid-modified polyolefin resins include homopolymers such as nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon MXD6 (polymetaxylylene adipamide), These copolymers, mixtures, etc. are mentioned. Polyamide resins are preferably used in the present invention because they are excellent in flexibility.

  In the monofilament of the present invention, the filament surface is composed of the above-mentioned blend body, but the thermoplastic resin constituting the filament may be of a single phase composed of only the above-mentioned blend body, The filament surface may be composed of a blend, and other than the surface, the filament surface may be composed of another thermoplastic resin. By placing a specific blend on the filament surface, it is possible to improve the adhesion and bondability with the sheath material when monofilament is used as a tension member. Therefore, considering the adhesion and bondability, the filament surface is specified. The desired purpose is achieved if it is completely covered by the blend. In order to further improve the strength of the monofilament, it is preferable to arrange a blend on the filament surface and arrange another thermoplastic resin capable of improving the strength on the core of the filament.

  When the monofilament of the present invention is a composite form, it is preferably a core-sheath composite form. That is, the blend is disposed in the sheath portion, and another thermoplastic resin is disposed in the core portion. As the thermoplastic resin disposed in the core portion, it is preferable to dispose the above-described polyamide-based resin in consideration of compatibility with the sheath portion. In particular, considering the improvement in mechanical strength, it is preferable to dispose nylon MXD6 in the core. By using nylon MXD6, a monofilament can be obtained because of excellent mechanical strength, dry heat shrinkage, flexibility, operability during melt spinning, and the like. By using a core-sheath monofilament with nylon MXD6 in the core and a blended body in the sheath, for example, when used as a tension member, it can protect optical fibers and processability when creating optical cables. Will also be excellent. Furthermore, the cables obtained can be sufficiently reinforced, and the toughness when the cables are used indoors and outdoors can be further increased.

  In the core-sheath composite type monofilament, it is preferable that one core is present in the center of the cross section of the filament, but in some cases, a plurality of cores having a number of about 2-3 are present. (Also called sea-island type).

  The ratio (mass ratio) between the resin constituting the core part and the resin constituting the sheath part is preferably core / sheath = 4/1 to 2/1. Considering the strength of the monofilament, it is preferable that the ratio of the core portion is large, but the ratio of the core portion is too large, and the sheath portion is difficult to cover the filament surface well, and the core portion is partly on the filament surface. When exposed, the object of the present invention may not be achieved. Therefore, considering the strength of the monofilament and that the core portion can be completely covered with the sheath portion, the above range is preferable.

  When a monofilament is used as a tension member, it is required to have high strength in order to reinforce cables and to be stable against heat and humidity. Therefore, the monofilament has a strength of 150 N or more and a dry heat shrinkage of 3% or less.

  The strength of the filament is measured at a grip interval of 25 cm and a tensile speed of 30 cm / min based on the standard time test of tensile strength and elongation of JIS L1013. If the monofilament has a strength of less than 150 N, the strength is insufficient, and the cables may be broken during production or use, and the cables cannot be sufficiently reinforced. The strength of the monofilament is preferably 200 N or more, more preferably 250 N or more.

The dry heat shrinkage of the filament is measured from the length after treatment at a treatment temperature of 140 ° C. for 30 minutes based on the shrinkage and dry heat shrinkage of JIS L1013. When the dry heat shrinkage rate exceeds 3%, for example, when a cable is formed by coating a cable and a monofilament with a sheath material, the cable is melt-coated with a resin constituting the sheath material. As a result, the monofilament is greatly shrunk, and the sheath material is cracked or cracked, or the shape of the monofilament is distorted by the shrinkage and the linearity is lost.
A monofilament having such strength and dry heat shrinkage can be obtained, for example, by adjusting the stretching and heat treatment conditions to those in an appropriate range by a manufacturing method described later.

  In addition, the monofilament of the present invention has an adhesion pulling strength in consideration of the adhesion to polyethylene of 0.1 times or more as an index of excellent adhesion / bondability to the sheath material when used as a tension member. It is preferable that it is 0.2 times or more. That is, the adhesive pulling strength is preferably 25N or more, and more preferably 30N or more.

  The adhesion pulling strength is measured as follows. A polyethylene chip 10 g is put in a cylindrical aluminum cup No. 5 having a diameter of 0.7 mm and a height of 13 mm, in which a hole for passing a monofilament is previously formed, and is melted by heat treatment at 190 ° C. for 20 minutes. Before the polyethylene solidifies, the monofilament is passed through and cooled and solidified at 25 ° C. for 60 minutes. Then, fix the container so that it does not move when the container is pulled out with the bottom face up, and place it in a tensile tester. While pulling the monofilament at a pulling speed of 50 mm / min, the strength at the time of pulling is measured, and the maximum value of this strength is defined as the adhesive pulling strength.

  In particular, polyethylene is often used for the sheath material of an optical cable. Therefore, when using a monofilament as a tension member, the adhesive pulling strength showing the adhesiveness with polyethylene as described above is an important characteristic value. Since the monofilament of the present invention has a blend containing a specific modified polyolefin resin on the filament surface, the modified polyolefin resin is present on the monofilament surface, and the adhesion pulling strength can be improved. It becomes possible to make the drawing strength 30N or more.

  The diameter of the monofilament in the present invention may be appropriately selected according to the application and required performance, and may be appropriately selected as long as it can maintain the required strength. However, about 0.4 mm to 1.5 mm is practical.

  Next, the manufacturing method of the monofilament of this invention is demonstrated using an example. Each chip was prepared so that nylon MXD6 in the core and acid-modified low molecular weight polyolefin resin and polyamide resin such as nylon 6 were arranged in the sheath, and the spinning temperature was about 275 ° C. The two types of resin in the sheath are melt-spun from the spinneret while chip blending, and the spun yarn is cooled in a hot water bath at 60 ° C. to obtain an undrawn yarn. This unstretched yarn is stretched in the first stage (stretching ratio: 2.8 to 3.5 times) in a 90 ° C. water bath, and then in the hot air atmosphere at 215 ° C. (stretching ratio: 1). .1 to 2.0 times). Subsequently, a relaxation heat treatment of 2.5 to 8% is performed in a hot air atmosphere at about 240 ° C. to obtain the monofilament of the present invention.

  In the monofilament of the present invention, a blend of an acid-modified low-molecular-weight polyolefin resin having a carboxylic anhydride group and a polyamide-based thermoplastic resin is arranged on the filament surface. In addition, the work environment and operability during production are excellent. Moreover, since it is not necessary to coat the surface of the monofilament with a polyolefin resin layer, the production efficiency is good and the cost is low.

  Next, the present invention will be specifically described with reference to examples. Various characteristic values (strength, dry heat shrinkage, adhesion pulling strength) in the examples were measured by the methods described above.

Example 1
Nylon MXD6 chip (6121R manufactured by Mitsubishi Gas Chemical Co., Ltd.) placed in the core and acid-modified polyolefin resin chip (Sanyo Chemical Industries, Ltd. ) And a nylon 6 chip (BRF manufactured by Unitika Ltd.). Using an ordinary extruder-type melt spinning apparatus, melt spinning was performed at a temperature of 275 ° C. The two resin chips in the sheath were melt-spun in an extruder while chip blending so that the acid-modified polyolefin resin chip was 5% by mass and the nylon 6 chip was 95% by mass. The spun monofilament was cooled in a hot water bath at 60 ° C. to obtain an undrawn yarn. Without winding up the undrawn yarn, the heating zone at 215 ° C. was set so that the first stage drawing was performed at a draw ratio of 3.1 times in a 90 ° C. warm water bath and then the total draw ratio was 5.1 times. Second-stage drawing while passing (drawing ratio: 1.7 times), and further passing through a heating zone at 240 ° C. to perform a relaxation heat treatment of 0.96 times to obtain a monofilament having a core-sheath type composite cross section of the present invention. It was. The obtained monofilament had a fineness of 4510 dtex and a diameter of 0.7 mm.

Example 2
A monofilament was obtained in the same manner as in Example 1 except that the content of the acid-modified polyolefin-based resin (Umex 1001 manufactured by Sanyo Chemical Industries, Ltd.) in the sheath was 10% by mass. The obtained monofilament had a fineness of 4522 dtex and a diameter of 0.7 mm.

Example 3
A monofilament was obtained in the same manner as in Example 1 except that the content of the acid-modified polyolefin resin (Umex 1001 manufactured by Sanyo Chemical Industries, Ltd.) in the sheath was 2.5 mass%. The obtained monofilament had a fineness of 4519 dtex and a diameter of 0.7 mm.

Comparative Example Nylon MXD6 chip (Mitsubishi Gas Chemical Co., Ltd. 6121R) on the core and nylon 6 chip (BRF made by Unitika) on the sheath so that the cross-section is a core-sheath composite type. Using a mold melt spinning apparatus, melt spinning was performed at a temperature of 275 ° C. The spun monofilament was cooled in a hot water bath at 60 ° C. to obtain an undrawn yarn. Without winding up the undrawn yarn, the heating zone at 215 ° C. was set so that the first stage drawing was performed at a draw ratio of 3.1 times in a 90 ° C. warm water bath and then the total draw ratio was 5.1 times. While being passed, the film was stretched in the second stage (stretching ratio: 1.7 times), further passed through a heating zone at 240 ° C. and subjected to a relaxation heat treatment of 0.96 times to obtain a monofilament. The obtained monofilament had a fineness of 4533 dtex and a diameter of 0.7 mm.

  Table 1 shows the characteristic values of the monofilaments obtained in Examples 1 to 3 and Comparative Example.

As is apparent from Table 1, the monofilaments obtained in Examples 1 to 3 were excellent in strength and dry heat shrinkage, and had a certain adhesion pulling strength. In particular, the monofilaments of Example 1 and Example 2 have high adhesion pulling strength values, and when used as tension members, are suitable as reinforcing materials for cables and cords in which polyolefin resin is used as a sheath material. It can be evaluated that it can be used.

Claims (3)

  The filament surface is constituted by a blended body obtained by blending an acid-modified polyolefin resin having a carboxylic anhydride group and a polyamide resin, and has a filament strength of 150 N or more and a dry heat shrinkage of 3% or less. Monofilament characterized by that.   The monofilament according to claim 1, wherein the monofilament according to claim 1 is a core-sheath composite cross section, the core is made of a polyamide-based resin, and the sheath is made of a blend. The monofilament according to claim 2, wherein the polyamide resin constituting the core portion is nylon MXD6.