JP2015232187A - Polyolefin-based fiber and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin-based fiber having high tensile strength and high tensile elastic modulus and a manufacturing method therefor.SOLUTION: The polyolefin-based fiber is a polyolefin-based fiber containing 0.01 pt.mass to 10 pts.mass of a fluorine-based polymer based on 100 pts.mass of a polyolefin-based polymer and having tensile strength of 0.65 GPa to 1.6 GPa, and the fluorine-based polymer is preferably fibrillar. The manufacturing method of the polyolefin-based fiber includes blending 0.01 pt.mass to 10 pts.mass of a fluorine-based polymer based on 100 pts.mass of a polyolefin-based polymer and melting and mixing to obtain a molten resin, melting spinning the molten resin to obtain non-stretched yarn and drawing the non-stretched yarn with draw ratio of 16 times to 30 times.

Description

  The present invention relates to a high-strength, high-modulus polyolefin fiber used for industrial materials, interiors such as buildings and automobiles, medical / hygiene, and clothing, and a method for producing the same.

  Polyolefin fiber is excellent in water repellency and non-water absorption, light and warm due to low specific gravity and low thermal conductivity, and has characteristics such as excellent chemical resistance. It is widely used for interiors of goods and automobiles, medical / hygiene, and clothing. The polyolefin fibers are required to further improve mechanical properties such as strength and elastic modulus.

  As a method for increasing the elastic modulus of polyolefin fibers, a method of adding a crystal nucleating agent such as talc is widely known. In Patent Document 1, in a polyolefin fiber used as a reinforcing fiber for a composite material, a metal salt of a fatty acid having 10 or more carbon atoms is added in order to improve bondability with a matrix resin. It is disclosed that the addition of a metal salt has an effect of increasing the elastic modulus of the polyolefin fiber.

  However, the method of increasing the elastic modulus by adding a metal salt of talc or fatty acid or a quasicrystalline functional polymer may impair the properties of the polyolefin resin such as non-water absorption, low specific gravity, and chemical resistance.

  By the way, since polyolefin resin is inexpensive and excellent in physical properties, it is widely used in the field of general resin molding. However, since polyolefin resin has a low melt viscosity, resin drawdown is a problem in injection molding and blow molding. In addition, there is a disadvantage that the rigidity is lower than that of ABS resin or the like. In order to solve such problems, in the field of resin molding, for example, in Patent Document 2 and Patent Document 3, polytetrafluoroethylene is mixed with thermoplastic polyolefin such as polypropylene and polyethylene to improve the moldability of the polyolefin resin. It is disclosed that it is improved.

  Due to the low melt viscosity of the polyolefin resin, there is a disadvantage that drawdown occurs in fiber spinning. In order to prevent such drawdown during spinning, for example, Patent Document 4 discloses a mixed powder composed of polytetrafluoroethylene and an alkyl (meth) acrylate polymer having 5 to 30 carbon atoms in an alkyl group in a fiber form. It is disclosed that they are present in a uniformly dispersed manner in a polyolefin. However, it has been impossible to increase mechanical properties such as strength and elastic modulus to target values.

  Further, Patent Document 5 discloses a technique in which a mixed powder of a fluorine-based polymer powder and an organic polymer powder is blended with a polyolefin-based resin, melt-mixed, and melt-spun under a draft ratio of 20 or more. Yes. The obtained polyolefin fiber contains 0.001 to 5% by mass of a fibrillar fluorine-based polymer, and the tensile elastic modulus is improved to 2.0 GPa. However, improvement of mechanical properties is still desired.

JP-A-7-243119 JP-A-5-214184 JP-A-6-306212 JP 2000-303252 A JP 2002-220729 A

  An object of the present invention is to provide a polyolefin fiber having a high tensile strength and a high tensile elastic modulus and a method for producing the same.

  The polyolefin fiber of the present invention is a polyolefin fiber containing 0.01 to 10 parts by mass of a fluoropolymer with respect to 100 parts by mass of a polyolefin polymer and having a tensile strength of 0.65 GPa to 1.6 GPa. .

  In the polyolefin-based fiber of the present invention, the fluorine-based polymer is preferably fibril.

The polyolefin fiber of the present invention preferably has a fibril diameter of the fluoropolymer of 0.1 nm to 50 nm.

  The polyolefin fiber of the present invention preferably has a tensile modulus of 12.2 GPa to 20 GPa or less.

  In the polyolefin-based fiber of the present invention, the fluorine-based polymer is preferably polytetrafluoroethylene, and the polyolefin-based polymer preferably includes 80% by mass or more of polypropylene.

  In the method for producing a polyolefin fiber of the present invention, 0.01 parts by mass to 10 parts by mass of a fluorine-based polymer is blended with 100 parts by mass of a polyolefin polymer, melt-mixed, melt-spun, and a draw ratio of 16 is obtained. It is a method for producing a polyolefin-based fiber comprising stretching at a magnification of 30 to 30 times.

  In the method for producing a polyolefin fiber of the present invention, the ratio (A / B) of the fiber winding speed A and the average discharge linear speed B of the molten polymer at the discharge hole is preferably from 1.5 to 100.

  The method for producing a polyolefin fiber according to the present invention is such that the fluoropolymer is mixed into a polyolefin polymer by mixing 100 mass parts of an organic polymer powder and 20 mass parts to 300 mass parts of a fluoropolymer powder. It is preferable to do.

  In the method for producing a polyolefin fiber of the present invention, the stretching temperature is preferably 110 ° C to 190 ° C.

  According to the present invention, a polyolefin fiber having a high tensile strength and a high elastic modulus can be obtained. In addition, high production is possible because of high stretchability.

Such polyolefin fiber can be suitably obtained by the production method of the present invention described later.
The polyolefin fiber of the present invention and the production method thereof will be described in detail below.
<Polyolefin fiber>
The polyolefin-based fiber obtained by the present invention is characterized by containing 0.01 to 10 parts by weight of a fluorine-based polymer with respect to 100 parts by weight of the polyolefin-based polymer.

  In the polyolefin fiber of the present invention, it is important to set the content of the fluoropolymer in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the polyolefin polymer. If the content of the fluoropolymer is 0.01 parts by mass or more, the effect of improving the strength and elastic modulus is sufficient, which is preferable. Moreover, if content of a fluorine-type polymer is 10 mass parts or less, the dispersibility of a fluorine-type polymer is favorable and there is little fall of a spinnability. From the above viewpoint, the content of the fluoropolymer is preferably 0.1 part by mass to 8 parts by mass, and more preferably 0.2 part by mass to 5 parts by mass.

  The polyolefin fiber of the present invention has a tensile strength of 0.65 GPa to 1.6 GPa. The tensile modulus is 12.2 GPa to 20 GPa. If the tensile strength of the polyolefin fiber is 0.65 GPa or more, it can be suitably used for industrial materials.

In the polyolefin fiber of the present invention, the fluorine polymer in the fiber is preferably fibril. A fibril shape is a fiber form, and a fibril diameter (diameter of a cross section perpendicular to the fiber axis direction) is in the order of nanometers to micrometers.
The fibril shape is preferably as thin as possible and has a larger number. It is considered that the fibril diameter is narrow and the gap between adjacent fibrils is narrowed by increasing the number of the fibrils, and the three-dimensional crystal growth of polyolefin can be suppressed. That is, the crystallization of the polyolefin is promoted to increase the crystallinity, and the crystal of the polyolefin grows along the fibril of the fluoropolymer to improve the crystal orientation. Is thought to improve.

  In the present invention, the fibril diameter of the fluorinated polymer is preferably 0.1 nm to 50 nm. If it is 50 nm or less, it is preferable at the point of the dispersibility of a fluorine-type polymer. More preferably, it is 30 nm or less, More preferably, it is 15 nm or less.

  It is important that the polyolefin fiber of the present invention is uniformly dispersed in the polyolefin resin without the fibrillar fluoropolymers being associated with each other. The rate is 4.0 GPa or more.

  Furthermore, the polyolefin fiber of the present invention can be highly stretched by containing a fibrillar fluoropolymer. The tensile strength of the polyolefin fiber obtained by highly drawing can be 0.65 GPa or more, and the tensile modulus can be 12.2 GPa or more.

There is no restriction | limiting in particular as a fluorine-type polymer used for this invention if it can become a fibril form, For example, a polytetrafluoroethylene can be mentioned as a representative example.
Polytetrafluoroethylene is obtained by polymerizing a monomer containing tetrafluoroethylene as a main component by a known method. In addition, as long as the properties of polytetrafluoroethylene are not impaired, the copolymer component may contain fluorinated olefins such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, perfluoroalkyl vinyl ether, and perfluoroalkyl (meth) acrylate. Fluorine alkyl (meth) acrylate can also be included.
Among these, examples of the fluorine-based polymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride. Among them, polytetrafluoroethylene which has a large number of fluorine atoms in the molecule and tends to form a fibril is preferred.
The copolymer component is preferably 10% by mass or less based on the copolymer from the viewpoint of fibrillation.

  The polyolefin in the present invention is not particularly limited as long as it is a polyolefin generally used for fibers. Examples thereof include homopolymers such as polypropylene, polyethylene, polybutene-1, and polymethylpentene, copolymers, and modified products thereof, and these may be used alone or in combination of two or more. Particularly preferred for fiber shaping are those mainly composed of polypropylene and polyethylene. Polypropylene is preferably 80% by weight or more.

       Moreover, it is preferable that the fluoropolymers are arranged in the fiber axis direction. At the time of spinning, the fibrillar fluorine-based polymer is easily arranged in the discharge direction in the polyolefin resin, and as a result, the degree of crystal orientation of the polyolefin is also improved.

  Furthermore, for the fibers of the present invention, known lubricants, processing aids, impact modifiers, fillers, mold release agents, foaming agents, pigments, ultraviolet absorbers, antifogging agents, antibacterial agents, electrification may be used as necessary. An inhibitor, a surfactant, a flame retardant, or the like may be added.

<Manufacturing method>
As a method for producing a polyolefin fiber of the present invention, 0.01 to 10 parts by mass of a fluoropolymer is blended with 100 parts by mass of a polyolefin polymer to obtain a molten resin by melting and mixing, The resin is melt-spun to obtain an undrawn yarn, and the undrawn yarn is drawn at a draw ratio of 16 to 30 times.

When blending the fluoropolymer with a polyolefin resin, it is preferable to use a powder in which the fluoropolymer and an organic polymer are mixed.
When an organic polymer is mixed with the fluoropolymer, the organic polymer has a high affinity with the polyolefin resin, and the fluoropolymer is easily dispersed uniformly in the polyolefin resin, which is preferable.

  The organic polymer mixed and adjusted with the fluoropolymer is not particularly limited, but is characterized in that a polymer having a high affinity with the polyolefin resin is used as the organic polymer. When the organic polymer having a high affinity with the polyolefin resin is adopted, it is preferable because dispersibility when blended with the polyolefin resin is improved.

  Specific examples of the monomer for producing the organic polymer include styrene monomers such as styrene, p- or o-methylstyrene, p- or o-chlorostyrene, p- or o-methoxystyrene. , Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate , (Meth) acrylate monomers such as tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate; olefin monomers such as ethylene, propylene, isobutylene; acrylonitrile, meta Vinyl cyanide monomers such as rilonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; dienes such as butadiene, isoprene and dimethylbutadiene Based monomers. These monomers can be used alone or in admixture of two or more.

  Among these monomers, styrene monomers, (meth) acrylate monomers, and olefin monomers are preferable from the viewpoint of affinity with polyolefin resins. Particularly preferable is a content of 20% by mass or more of one or more monomers selected from the group consisting of long chain alkyl (meth) acrylate monomers having 5 or more carbon atoms, styrene and olefin monomers. Can be mentioned.

The mixed powder preferably contains 20 to 300 parts by mass of the fluoropolymer with respect to 100 parts by mass of the organic polymer.
If the mixed powder is 20 parts by mass or more of the fluoropolymer with respect to 100 parts by mass of the organic polymer, it is preferable in terms of fiber physical properties, and if it is 300 parts by mass or less, the dispersibility of the fluoropolymer can be reduced. This is preferable. More preferably, they are 25 mass parts-250 mass parts, More preferably, they are 30 mass parts-200 mass parts.

  The particle size of the fluoropolymer fine particles when dispersed in the polyolefin resin is preferably 0.05 to 1.0 μm. If the particle size of the fluoropolymer fine particles is 0.05 μm or more, it is preferable from the viewpoint of fibrillation, and if it is 1.0 μm or less, it is preferable from the viewpoint of dispersibility of the fluoropolymer. More preferably, it is 0.1 micrometer-1.0 micrometer, More preferably, it is 0.2 micrometer-1.0 micrometer.

  In the fluorinated polymer-containing mixed powder, it is preferable that the fluorinated polymer is dispersed as fine particles as uniformly as possible. For example, it is preferably produced by the following method. That is, it can be obtained by a method of mixing an aqueous dispersion of fluoropolymer fine particles having a particle diameter of 0.05 μm to 1.0 μm and an aqueous dispersion of organic polymer particles and coagulating or spray drying.

  Alternatively, it can also be obtained by a method in which a monomer constituting an organic polymer is polymerized in the presence of an aqueous dispersion of fluorine-based polymer fine particles having a particle diameter of 0.05 μm to 1.0 μm and then coagulated or spray-dried. Alternatively, a monomer having an ethylenically unsaturated bond is further emulsion-polymerized in a dispersion obtained by mixing an aqueous dispersion of fluoropolymer fine particles and an aqueous dispersion of organic polymer particles, and then coagulated or spray-dried. Methods can also be used.

  The mixed powder containing a fluoropolymer and an organic polymer obtained by using such an aqueous dispersion takes a composite form in which the organic polymer surrounds the fluoropolymer fine particles by any method. In addition, since the fluorine-based polymer alone does not form a domain having a particle diameter exceeding 10 μm, the dispersibility with respect to the polyolefin-based resin is extremely excellent.

The fiber of the present invention is, for example, a melt extruder in which a mixed powder prepared by mixing and adjusting a mixed powder containing a fluoropolymer powder and an organic polymer powder is added to a polyolefin resin such as crystalline polypropylene. It can be obtained by melt-kneading and dispersing it in a polyolefin resin, and then melt spinning as it is.

  Alternatively, a mixed powder containing a fluoropolymer powder and an organic polymer powder is melt-mixed in a small amount of polyolefin resin to once produce a master batch or master pellet having a high fluoropolymer content. Further, it may be mixed with a larger amount of polyolefin resin during spinning.

In order to make the fluorine-based polymer into the fine fibrils as described above, it is effective to use a mixed powder containing a fluorine-based polymer including a powder of a fluorine-based polymer and a powder of an organic polymer.
When the organic polymer is contained, the dispersibility of the fluorine-based polymer is improved, so that it is easy to form a fine fibril.

In order to make the fluorine-based polymer into a fine fibril form, it is necessary to uniformly disperse the fluorine-based polymer in the polyolefin resin and then apply a sufficient shearing force to the fluorine-based polymer with a kneader or the like.
What is necessary is just to adjust suitably the magnitude | size of shear force, the time which gives a shear force, etc. so that a fibril diameter may be set to 0.1 nm-50 nm.

  As a spinning method, melt spinning of a general polyolefin resin is used. Under general melt spinning temperature conditions, the fluoropolymer may be in a softened state without melting, but even in such a softened state, it passes through the kneading process and nozzle discharge holes. Due to the shearing force, the fluorinated polymer becomes a fibrillar shape.

  In the present invention, in order to increase the crystal orientation degree of the polyolefin polymer of the obtained fiber and obtain the effect of improving the strength and elastic modulus, as described above, a fluorinated polymer dispersed in a fine fibril form in the fiber axis direction. It is necessary to arrange.

In the method for producing a polyolefin fiber of the present invention, it is important to stretch the melt-spun undrawn yarn at a high magnification in order to arrange the fluoropolymer dispersed in a fine fibril shape in the fiber axis direction. It is preferable to draw at a draw ratio of 16 times to 30 times.
If the draw ratio is 16 times or more, it is preferable from the viewpoint of high strength and high elastic modulus, and if it is 30 times or less, it is preferable from the viewpoint of drawing stability. The draw ratio is more preferably 16 times to 28 times, and still more preferably 16 times to 25 times.

When stretching, it is preferable to heat the unstretched yarn using a hot air furnace or a hot plate because the temperature of the unstretched yarn is increased, and it is preferable to heat the unstretched yarn. Is preferably 100 ° C. to 190 ° C.
If the stretching temperature is 100 ° C. or higher, it is preferable in terms of stretchability, and if it is 190 ° C. or lower, it is preferable in terms of not causing melt fracture. The stretching temperature is more preferably 100 ° C to 180 ° C, and further preferably 100 ° C to 170 ° C.

Moreover, regarding the crystal orientation degree of polyolefin, the influence of the elongation deformation degree of the molten resin discharged from the discharge hole of the nozzle is large. The elongation deformation degree of the molten resin discharged from the discharge hole of the nozzle is expressed by a draft ratio which is a ratio (A / B) of the fiber winding speed A and the average discharge linear speed B of the molten polymer at the discharge hole portion. .
The draft ratio is preferably 1.5 to 100. If the draft ratio is 100 or less, sufficient stretchability can be secured in the subsequent stretching step. The draft ratio is more preferably 11 to 50, still more preferably 15 to 30.

  As described above, a polyolefin fiber having a high tensile strength and a high tensile modulus can be produced by drawing an undrawn yarn at a high magnification.

  The draw ratio is determined from the ratio of the peripheral speeds of the supply roller and the take-up roller when the undrawn yarn is drawn.

  Hereinafter, the present invention will be described more specifically with reference to examples. The examples described below are examples of the best mode of the present invention, but the present invention is not limited to these examples.

(Tensile strength, tensile modulus)
The tensile strength and tensile modulus were measured using an autograph manufactured by Shimadzu Corporation. The test length was 20 mm and the tensile speed was measured at 20 mm / min. The number of tests was five, and the average value was obtained.

(Fibril diameter)
The obtained fiber was embedded with an epoxy resin for an electron microscope, a section having a thickness of about 80 nm was cut out using a microtome, observed with a transmission electron microscope, and 50 pieces on a photograph baked 30,000 times. The average value was obtained by measuring the diameter of the fibrils. In the comparative example, when the number of fibrils was small, the diameter of 10 fibrils was measured to obtain an average value.

(Example 1)
A polypropylene resin (Y2000GV manufactured by Prime Polymer Co., Ltd.) and a mixed powder containing a fluorine-based polymer (A-3000 manufactured by Mitsubishi Rayon Co., Ltd.) were mixed at a mass ratio shown in Table 1, and the mixture was introduced into a twin-screw kneading extruder. Strands were obtained by melt-kneading at 600 ° C. for 20 minutes at 600 ° C. The obtained strand was cut into pellets using a pelletizer. The obtained pellets were put into a melt spinning apparatus and extruded from a nozzle having a diameter of 0.8 mm, and the spinning temperature and draft ratio were spun as shown in Table 1 to obtain an undrawn yarn. The obtained undrawn yarn was drawn in a heat tube at the draw ratio and temperature shown in Table 1 to obtain a polypropylene fiber having a single fiber fineness of 7 dtex. The polypropylene fiber had a tensile strength of 1.01 GPa and a tensile elastic modulus of 12.5 GPa.
The fibril diameter was about 8 nm.

(Examples 2 to 6)
A polypropylene fiber was obtained under the same conditions as in Example 1 except that the undrawn yarn obtained in the Example was drawn at the draw ratio and temperature shown in Table 1. The results of the tensile strength and tensile modulus of the obtained polypropylene fiber are shown in Table 1.

(Example 7)
Polypropylene resin (FY-4 manufactured by Nippon Polypro Co., Ltd.) and a fluorine-containing polymer-containing mixed powder (A-3000 manufactured by Mitsubishi Rayon Co., Ltd.), so that the mass ratio of polypropylene resin and fluorine-based polymer is as shown in Table 1. The mixture is introduced into a twin-screw kneading extruder, melted and kneaded at 250 ° C. and 30 rpm for 10 minutes to form a molten resin, and the molten resin is continuously extruded from a discharge hole of a nozzle having a diameter of 0.75 mm. It was made into a fiber and spun at a draft ratio shown in Table 1 to obtain an undrawn yarn. The obtained undrawn yarn was drawn at a draw ratio and temperature shown in Table 1 in a hot air oven to obtain a polypropylene fiber having a single fiber fineness of 85 dtex. The polypropylene fiber had a tensile strength of 0.88 GPa and a tensile modulus of 12.7 GPa.

(Example 8)
Table 1 shows polypropylene resin (FY-4 manufactured by Nippon Polypro Co., Ltd.), fluorine-containing polymer-containing mixed powder (A-3750 manufactured by Mitsubishi Rayon Co., Ltd.), and PVDF (KF-850) manufactured by Kureha as a fluorine-based polymer. A polypropylene fiber having a single fiber fineness of 160 dtex was obtained under the same conditions as in Example 7 except that mixing was performed at a mass ratio. The physical properties of the obtained polypropylene fiber are as shown in Table 1.

Example 9
A polypropylene fiber having a single fiber fineness of 136 dtex was obtained in the same manner as in Example 8 except that the draw ratio was set as shown in Table 1. The physical properties of the obtained polypropylene fiber are as shown in Table 1.

(Comparative Examples 1-3)
In Comparative Examples 1 to 3, only the polypropylene resin (FY-4 manufactured by Nippon Polypro Co., Ltd.) was melt kneaded and extruded. It was melt-kneaded at 220 ° C. and 100 rpm for 10 minutes, and continuously extruded from a discharge hole of a nozzle having a diameter of 0.75 mm to obtain an undrawn yarn. The spinning temperature and draft ratio are as shown in Table 1. The obtained undrawn yarn was drawn at a draw ratio shown in Table 1 in a hot air oven at 100 ° C. to obtain a final polypropylene fiber. The physical properties of the final polypropylene fiber are as shown in Table 1.

Claims (9)

  A polyolefin fiber comprising 0.01 to 10 parts by mass of a fluoropolymer with respect to 100 parts by mass of a polyolefin polymer and having a tensile strength of 0.65 GPa to 1.6 GPa.   The polyolefin fiber according to claim 1, wherein the fluorine-based polymer is in a fibril form.   The polyolefin fiber according to claim 1 or 2, wherein the fibril-like fibril diameter of the fluoropolymer is 0.1 nm to 50 nm.   The polyolefin fiber according to any one of claims 1 to 3, which has a tensile modulus of 12.2 GPa to 20 GPa.   The polyolefin fiber according to any one of claims 1 to 4, wherein the fluoropolymer is polytetrafluoroethylene, and the polyolefin polymer contains 80% by mass or more of polypropylene.   Blending 0.01 parts by mass to 10 parts by mass of a fluoropolymer with respect to 100 parts by mass of a polyolefin polymer to obtain a molten resin by melting and mixing, and melt spinning the molten resin to obtain an undrawn yarn And a method for producing a polyolefin-based fiber, comprising drawing an undrawn yarn at a draw ratio of 16 to 30 times.   The method for producing a polyolefin-based fiber according to claim 6, wherein the ratio (A / B) of the fiber winding speed A and the average discharge linear speed B of the molten polymer at the discharge hole is 1.5 to 100.   The said fluoropolymer is made into the mixed powder which consists of 20 mass parts-300 mass parts of fluoropolymer powder with respect to 100 mass parts of organic polymer powder, and mix | blends with a polyolefin polymer. Manufacturing method of polyolefin fiber.   The method for producing a polyolefin-based fiber according to any one of claims 6 to 8, wherein the extending atmospheric temperature is 110 ° C to 190 ° C.