CN108495959B

CN108495959B - Colored polyethylene fiber and method for producing same

Info

Publication number: CN108495959B
Application number: CN201780007375.2A
Authority: CN
Inventors: 福岛靖宪; 石田诚治; 西村浩和; 冈本达志; 古田明久; 奥山幸成; 福西范树; 吉崎贤一
Original assignee: Toyobo Co Ltd
Current assignee: Dongyang Textile Mc Co ltd
Priority date: 2016-02-24
Filing date: 2017-02-23
Publication date: 2021-07-06
Anticipated expiration: 2037-02-23
Also published as: TWI715733B; TW201800640A; CN108495959A

Abstract

The colored polyethylene fiber of the present invention has an L value of 80 or less based on the CIE-L a b color system, and has a color fastness to rubbing of 3 or more in the dry state and the wet state, or has a solvent resistance of 75% or more by a predetermined measurement method. Thus, the colored polyethylene fiber of the present invention is colored in a deep color, and is not easily discolored or matted, and further, is uniformly dyed with little unevenness and has high strength.

Description

Colored polyethylene fiber and method for producing same

Technical Field

The present invention relates to a coloured polyethylene fibre.

Background

Conventionally, various techniques have been disclosed as methods for producing colored fibers. However, since the high-strength polyethylene has a simple chemical structure and a very high crystallinity, there are the following problems: it is difficult to obtain a polyethylene fiber having a color tone and color fastness satisfying the market requirements. In order to solve the above problems, for example, patent document 1 discloses a method of adding a dye from a raw material preparation stage to dye a yarn as a dope, and patent document 2 discloses a method of applying a dye to an intermediate drawn yarn under heating.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3143886

Patent document 2: japanese patent laid-open publication No. 4-289212 "

Disclosure of Invention

Problems to be solved by the invention

However, in the case of a dope dyed yarn, there is a problem that it is difficult to color a deep color because there is a limit to the concentration of the dye that can be added in the raw material preparation step. Further, when a dye is applied to the intermediate drawn yarn under heating, there are problems as follows: the thermal history applied to the intermediate drawn yarn affects the subsequent drawing, and unevenness in thickness of the fiber occurs, and it is difficult to achieve uniform strength in the longitudinal direction of the fiber and dyeing with less unevenness.

Accordingly, an object of the present invention is to solve the above conventional problems. Namely, the object is to provide: a colored polyethylene fiber which is colored in a dark color, is less likely to be discolored, and has a high strength and which is uniformly dyed with less unevenness, and a process for producing the same.

Means for solving the problems

The present inventors have made extensive studies to solve the above problems, and as a result, have found that: the present inventors have found that a colored polyethylene fiber having a deep color and excellent color fastness can be obtained by applying a coloring material to a polyethylene fiber under specific conditions and performing a heat treatment process.

That is, the colored polyethylene fiber of the present invention is characterized in that,

the color system has an L value of 80 or less based on CIE-L a b and a color fastness to rubbing of 3 or more in both dry and wet states.

In addition, in the colored polyethylene fiber of the present invention, it is preferable that the Coefficient of Variation (CV) defined by the following formula 1 of the tensile strength measured at any 10 positions in the longitudinal direction is 10% or less.

Coefficient of variation (%) in tensile strength (standard deviation of tensile strength/average value of tensile strength) × 100 (formula 1)

In addition, the colored polyethylene fiber of the present invention preferably has an acid value of 0.1mgKOH/g or more and 50mgKOH/g or less.

Alternatively, the colored polyethylene fiber of the present invention preferably contains a surfactant having an HLB value (Hydrophile-Lipophile Balance) of 7.0 to 14.0% of 0.4 to 5.0%.

The present invention also includes a colored polyethylene fiber having a solvent resistance of 75% or more as determined by the following measurement method.

[ method for measuring solvent resistance ]

The colored polyethylene fiber was immersed in acetone so as to be 0.1g/mL and allowed to stand at room temperature for 24 hours. The transmittance in the wavelength range of 350nm to 780nm was measured using an ultraviolet-visible spectrophotometer for acetone used for dipping the colored polyethylene fiber and acetone obtained by dipping the colored polyethylene fiber and allowing it to stand at 20 ± 5 ℃ for 24 hours, the integral value of the transmittance in the above wavelength region was obtained from the obtained transmittance curve, and the solvent resistance was calculated by the following formula 2.

Solvent resistance (%) - (T)₁/T₀) X 100 (formula 2)

In the formula 2, T₀T represents the integral value of the transmittance of acetone at a wavelength of 350nm to 780nm₁The integrated value of the transmittance of acetone after the colored polyethylene fiber having a wavelength of 350 to 780nm was impregnated is shown.

In the colored polyethylene fiber of the present invention, it is preferable that the fineness in the longitudinal direction is not 10% or less. Further, the tensile strength is preferably 18cN/dtex or more. Further, the colored polyethylene fiber of the present invention preferably contains a coloring material which is an oil-soluble dye. The monofilament fineness of the colored polyethylene fiber of the present invention is preferably 1dtex or more and 80dtex or less.

Further, the present invention includes: a braid comprising at least 1 of the above colored polyethylene fibers, a fishing line, a glove, a rope, a net, a fabric or a woven fabric comprising the above colored polyethylene fibers. The strength of the fiber unwound from the braid is preferably 15cN/dtex or more.

The method for producing a colored polyethylene fiber of the present invention is characterized by comprising the steps of:

a step of spinning a polyethylene solution obtained by dissolving a polyethylene having an intrinsic viscosity [. eta. ] of 5.0 to 25dL/g in an organic solvent so that the concentration of the polyethylene in the repeating unit thereof is 0.5 to 40 mass%, the polyethylene having an ethylene content of 90 mol% or more, to obtain a polyethylene fiber;

a step of bringing a polyethylene fibrous material containing less than 20 mass% of an organic solvent into contact with a coloring liquid containing a coloring material and an organic solvent and having a temperature of 0 ℃ or higher and less than 60 ℃;

heating a polyethylene fiber material to which a coloring liquid has been added and which contains an organic solvent in an amount of less than 25% by weight of the fiber at 110 ℃ for 10 seconds or longer; and the combination of (a) and (b),

and stretching the polyethylene fiber material.

a step of bringing the polyethylene fiber-like material into contact with a coloring liquid which contains a coloring material and a polyolefin having a hydrophilic group at one end and has a temperature of 0 ℃ or higher and lower than 60 ℃;

heating the polyethylene fibrous material to which the coloring liquid has been applied at 110 ℃ or higher for 10 seconds or longer; and the combination of (a) and (b),

and stretching the polyethylene fiber material.

a step of bringing the polyethylene fibrous material into contact with a coloring liquid containing a coloring material and a surfactant having an HLB (Hydrophile-Lipophile Balance) of 7.0 to 14.0 inclusive and having a temperature of 0 ℃ to less than 60 ℃;

and stretching the polyethylene fiber material.

In the method for producing a colored polyethylene fiber of the present invention, it is preferable that the temperature of the polyethylene fibrous material in contact with the coloring liquid is 50 ℃ or lower. Preferably, the heating is performed while applying a tension of 0.8 to 6.5cN/dtex to the polyethylene fibrous material to which the coloring liquid is applied. Preferably, the method includes the steps of: the polyethylene fiber-like material to which the coloring liquid has been applied is stretched at a stretch ratio of 2 times or more.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided: a colored polyethylene fiber which is colored in a dark color and has excellent color fastness to rubbing and/or solvent resistance. Further, the polyethylene fiber has high strength and is less in variation in strength and fineness, and therefore, it is suitably used as materials such as a braid, a fishing line, a glove, a rope, a net, a woven fabric, and a knitted fabric. In addition, if water is used as a solvent for the coloring material, the polyethylene fiber can be produced with reduced environmental load.

Detailed Description

The present invention will be described in detail below.

[ embodiment mode 1]

The colored polyethylene fiber of the present embodiment is characterized in that,

(I) a value of L based on the CIE-La b chromaticity system of 80 or less, and a color fastness to rubbing of 3 or more in both dry and wet states; or the like, or, alternatively,

(II) the solvent resistance determined by the following measurement method is 75% or more.

[ method for measuring solvent resistance ]

Solvent resistance (%) - (T)₁/T₀) X 100 (formula 2)

In the formula 2, T₀Showing acetone (blank, colored) in the above wavelength regionPolyethylene fiber not impregnated) of transmittance, T₁The integrated value of the transmittance of acetone after the colored polyethylene fiber in the wavelength region was impregnated is shown.

The colored polyethylene fiber of the present embodiment is colored in a dark color, and the L value obtained when the colored polyethylene fiber or a processed product obtained from the colored polyethylene fiber is measured by CIE-la-b color difference measurement is 80 or less. Smaller values of L indicate more colored polyethylene fibers. Therefore, the value of L is preferably 75 or less, more preferably 70 or less, and further preferably 65 or less. The lower limit of the L value is not particularly limited.

The colored polyethylene fiber of the present embodiment has excellent color fastness to rubbing. More specifically, the color fastness to rubbing is grade 3 or more both when dry and when wet. The higher the grade for crockfastness, the less discolorable and matted the fiber. Therefore, the color fastness to rubbing is preferably grade 4 or more, more preferably grade 5. The color fastness to rubbing was evaluated as follows: with respect to a sample prepared in accordance with JIS L0801 (2000), a rubbing fastness test in accordance with JIS L0849 (2004) was performed using a chemical vibration type rubbing tester, and evaluation was performed using a gray scale for staining (JIS L0805 (2005)). Details of the test and evaluation methods are illustrated in the examples.

The colored polyethylene fiber according to the present embodiment further includes the following colored polyethylene fibers: the solvent resistance determined by the measurement method described in the above (II) is 75% or more. The solvent resistance is preferably 80% or more, more preferably 85% or more. The solvent resistance is an index of the amount of the coloring material extracted from the colored polyethylene fiber, and the larger the value, the smaller the amount of the coloring material extracted from the colored polyethylene fiber. Therefore, the larger the value of the solvent resistance is, the more preferable the solvent resistance is 98% or more.

The colored polyethylene fiber preferably satisfies both of the above (I) and (II). The polyethylene fiber is colored in a deep color, has excellent resistance to friction and organic solvents, and is not likely to be discolored or overlapped.

The colored polyethylene fiber of the present embodiment preferably has a tensile strength of 18cN/dtex or more. The tensile strength is more preferably 20cN/dtex or more, and still more preferably 25cN/dtex or more. The upper limit of the tensile strength is not particularly limited, but it is technically and industrially difficult to obtain a polyethylene fiber having a tensile strength of more than 60 cN/dtex.

In addition, the colored polyethylene fiber preferably has a Coefficient of Variation (CV) (%) in tensile strength, which is determined by the following formula 1, of 10% or less, with respect to the tensile strength measured at any 10 positions in the longitudinal direction (longitudinal direction) of the fiber.

The coefficient of variation (%) in tensile strength is more preferably 9% or less, still more preferably 8% or less, and still more preferably 5% or less. The coefficient of variation (%) in tensile strength is preferably such that the variation in strength in the longitudinal direction of the polyethylene fiber within the above range is small.

The elongation (elongation) of the colored polyethylene fiber at the maximum strength is preferably 3.0% or more. More preferably 3.5% or more, and still more preferably 3.7% or more. The upper limit of the elongation is not particularly limited, but is preferably 6.0% or less.

The colored polyethylene fiber preferably has an initial elastic modulus of 500cN/dtex or more and 2000cN/dtex or less. The initial modulus of elasticity is more preferably 600cN/dtex or more, further preferably 700cN/dtex or more, more preferably 1600cN/dtex or less, further preferably 1400cN/dtex or less. If the initial elastic modulus is too high, it is difficult to form a polyethylene fiber into a rope or a braid during the molding process, and it is likely that a monofilament is cut.

The fineness of the monofilament constituting the colored polyethylene fiber is preferably 1dtex or more and 80dtex or less. When the single fiber fineness exceeds 80dtex, the polyethylene fiber becomes hard and it is difficult to improve the strength. Preferably 70dtex or less, more preferably 60dtex or less. Fibers having a fiber diameter of less than 1dtex may be easily fluffed during drawing in the production process thereof or during practical use of polyethylene fibers. Preferably 2dtex or more, more preferably 5dtex or more.

In addition, the variation in fineness (coefficient of variation in total fineness) of the colored polyethylene fiber is preferably 10% or less. When the fineness is not more than 10%, not only the strength unevenness is liable to occur, but also the coloring unevenness is liable to occur due to the fluctuation of the fineness, and the color tone of the appearance may fluctuate, but when the fineness is not more than 10%, the above problem is not liable to occur, and therefore, it is preferable. The fineness unevenness is more preferably 6% or less, and still more preferably 5% or less.

The colored polyethylene fibers comprise a coloring material. As the coloring material, an organic coloring material is preferable, and a dye soluble in an organic solvent is particularly preferably used. Examples of such coloring materials include oil-soluble dyes, disperse dyes, acid dyes, and cationic dyes. Among them, oil-soluble dyes and disperse dyes are preferable because they have good compatibility with polyethylene and can easily realize polyethylene fibers colored in a deep color. Examples of preferable oil-soluble dyes include c.i. solvent yellow 2 (hereinafter, referred to as "c.i. solvent yellow") 6, 14, 15, 16, 19, 21, 33, 56, 61, 80, c.i. solvent orange 1 (hereinafter, referred to as "c.i. solvent orange"), 2, 5, 6, 14, 37, 40, 44, 45, c.i. solvent red 1 (hereinafter, referred to as "c.i. solvent red"), 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, c.i. solvent violet 8 (hereinafter, referred to as "c.i. solvent violet"), 13, 14, 21, 27, c.i. solvent blue 2 (hereinafter, referred to as "c.i. solvent blue") 11, 12, 25, 58, 36, 55, 73, c.i. solvent green 3, and the like. Examples of the disperse dye include c.i. disperse red 4 (hereinafter, referred to as "c.i. disperse red"), 5, 11, 17, 60, 74, 75, 86, 91, 92, 152, 153, 167, 179, 200, 221, 302, a disperse dye classified as c.i. disperse black, c.i. disperse orange 3 (hereinafter, referred to as "c.i. disperse orange"), 13, 25, 31, 37, 45, 61, 76, a disperse dye classified as c.i. disperse gray, c.i. disperse yellow 3 (hereinafter, referred to as "c.i. disperse yellow"), 5, 42, 49, 79, 82, 104, 134, 149, 198, 211, 241, a disperse dye classified as c.i. disperse green, c.i. disperse violet 1 (hereinafter, referred to as "c.i. disperse violet"), 3, 28, 43, a disperse dye classified as c.i. disperse brown, c.i. disperse blue 1 (hereinafter, referred to as "c.i. disperse blue 1"), 106, 60, 165, 183, 257, 360, 183, and the like. These coloring materials may be used alone, or a plurality of coloring materials having different hues may be used in combination.

The amount of the coloring material contained in the colored polyethylene fiber is preferably 0.2 mass% or more and 5 mass% or less. More preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and still more preferably 2% by mass or more. The upper limit is more preferably 4% by mass or less, and still more preferably 3% by mass or less. When the content of the coloring material is within the above range, deep coloring can be achieved, and there is little concern about the influence on the mechanical properties of the fiber, which is preferable. The amount of the coloring material contained in the colored polyethylene fiber can be determined by the method described in the examples of the subsequent stage.

Next, the manufacturing method of the present embodiment will be described.

In the present embodiment, the colored polyethylene fiber is produced by a solution forming method. The solution forming method is not particularly limited as long as a conventionally known method is employed, and for example, the following solution spinning method is preferably employed: polyethylene is dissolved in a volatile organic solvent such as decalin and tetralin, or a nonvolatile organic solvent such as paraffin, and the polyethylene is formed into a fibrous form.

As the raw material polyethylene, a polyethylene having an intrinsic viscosity [ eta ] of 5.0dL/g or more and 25dL/g or less and containing ethylene in a repeating unit of 90 mol% or more is used. The intrinsic viscosity is more preferably 7.0 to 22dL/g, and still more preferably 8 to 20 dL/g. When the intrinsic viscosity is too low, the dimensional stability tends to be poor, and the change in mechanical properties with time tends to be large, and it is difficult to realize a strength of 10cN/dtex or more. On the other hand, when the intrinsic viscosity is too high, high strength and high elastic modulus are easily achieved, but there is a concern that the polyethylene fiber is frequently cut in a post-process of processing into a product such as a braid. When polyethylene having an intrinsic viscosity within the above range is used as a raw material, the number of structural defects in fibers and fiber products can be reduced by setting the molecular end group of the polyethylene to an appropriate range. As a result, mechanical properties such as strength and elastic modulus, dimensional stability, and abrasion resistance of the polyethylene fiber can be improved, and further, the change in mechanical properties over time can be suppressed.

More than 90 mol% of the repeating units of the raw material polyethylene are ethylene. The ethylene repeating unit is preferably 92 mol% or more, more preferably 94 mol% or more, and most preferably a homopolymer of ethylene. The polyethylene as a raw material may contain components other than ethylene as long as the components do not adversely affect the physical properties of the polyethylene fiber. For example, ethylene and a small amount of other monomers can be used as the raw material polyethylene, and specifically, a copolymer of ethylene and other monomers such as α -olefin, acrylic acid and its derivatives, methacrylic acid and its derivatives, and vinylsilane and its derivatives can be used as the raw material polyethylene.

The intrinsic viscosity may be within the above range, and the raw material polyethylene may be, for example, a blend containing a blend of high-density polyethylene and ultrahigh-molecular-weight polyethylene, or a blend of low-density polyethylene and ultrahigh-molecular-weight polyethylene, the polyethylene having different weight average molecular weights. Further, the raw material polyethylene may be a blend of 2 or more kinds of ultrahigh molecular weight polyethylenes having different weight average molecular weights, or a blend of 2 or more kinds of polyethylenes having different molecular weight distributions.

However, if the content of the component other than ethylene is excessively increased, the component may rather become a factor of inhibiting the stretching. Therefore, from the viewpoint of obtaining a high-strength fiber, the number of branches present in the polyethylene is preferably 3 or less per 1000 main chain carbon atoms. More preferably 2 or less, and still more preferably 1.5 or less.

Additives such as an antioxidant and a light-resistant agent may be added to the polyethylene as a raw material in order to suppress the deterioration of the physical properties of the polyethylene fiber. When an antioxidant is used as an additive, the mechanical properties such as strength of the colored polyethylene fiber can be suppressed, and the change in color tone can be suppressed. This is because the mechanism of deterioration of the coloring material by ultraviolet rays is considered to be basically the same as that of deterioration of the polyethylene fiber. Therefore, when the polyethylene fiber contains an antioxidant, the polyethylene fiber is inhibited from deteriorating in strength, and similarly, the coloring material is inhibited from deteriorating, and as a result, the change in color tone of the colored polyethylene fiber is also inhibited. The amount of the additive to be used is preferably 0.01 to 10 parts by mass per 100 parts by mass of the raw material polyethylene.

The polyethylene solution is prepared by dissolving the above raw material polyethylene in an organic solvent. The concentration of the polyethylene is 0.5 mass% or more and 40 mass% or less, preferably 2.0 mass% or more and 30 mass% or less, and more preferably 4.0 mass% or more and 20 mass% or less. When the polyethylene concentration is too low, the production efficiency tends to be lowered. On the other hand, when the concentration of polyethylene is too high, the molecular weight of polyethylene derived from the raw material is very large, and it tends to be difficult to discharge from a nozzle described later in the solution spinning method.

The organic solvent that dissolves the raw material polyethylene is preferably a solvent that dissolves the raw material polyethylene and has a boiling point of not less than the melting point of the raw material polyethylene, and more preferably an organic solvent that has a boiling point of not less than 20 ℃ higher than the melting point of the raw material polyethylene. Examples of the solvent include aliphatic hydrocarbon solvents such as n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane, and mobile paraffin and kerosene, aromatic hydrocarbon solvents such as xylene, naphthalene, tetrahydronaphthalene, decahydronaphthalene, butylbenzene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene, dodecylbenzene, dicyclohexyl, methylnaphthalene and ethylnaphthalene, or hydrogenated derivatives thereof, halogenated hydrocarbon solvents such as 1,1,2, 2-tetrachloroethane, pentachloroethane, hexachloroethane, 1,2, 3-trichloropropane, dichlorobenzene, 1,2, 4-trichlorobenzene and bromobenzene, paraffin process oils, naphthenic process oils and aromatic process oils. Among these organic solvents, volatile organic solvents are preferable because they can remove the organic solvents from the polyethylene fibrous material simultaneously with stretching in the stretching step described later.

The polyethylene solution is preferably heated at a temperature higher than the melting point of the raw material polyethylene by 10 ℃ or more (melting point of the raw material polyethylene +10 ℃ or more), and then passed through a spinning nozzle (spinneret) to form a polyethylene fibrous material (undrawn yarn) (spinning step). The heating temperature is more preferably +20 ℃ or higher of the melting point of the raw material polyethylene, and still more preferably +30 ℃ or higher of the melting point of the raw material polyethylene. By heating in the above temperature range, the raw material polyethylene dispersed in the organic solvent can be dissolved to form a uniform solution.

The temperature of the spinneret is preferably set to a melting point of the raw material polyethylene +5 ℃ or higher and a boiling point of the organic solvent used in the polyethylene solution or lower. More preferably, the melting point of the raw material polyethylene is +10 ℃ or higher. When the temperature of the spinneret is too low, the viscosity of the raw polyethylene decreases, and it may be difficult to collect the polyethylene fiber at a desired speed. On the other hand, when the temperature of the spinneret exceeds the boiling point of the organic solvent, the organic solvent may boil immediately after the polyethylene solution is discharged from the spinneret, and thus, a broken end may frequently occur immediately below the spinneret.

The spinning nozzle preferably has an orifice (hole) having a diameter of 0.2mm to 3.5 mm. The diameter of the orifice is more preferably 0.5mm to 2.5mm, and still more preferably 0.8mm to 2.0 mm.

The discharged molded product from the spinning nozzle was cooled, solidified, and collected to obtain a polyethylene fiber-like material. The cooling method is not particularly limited, and the molded product discharged from the spinneret may be naturally cooled by exposing the molded product to the atmospheric temperature, or a cooling device may be used. The cooling method by the cooling device may be a dry quenching method using a gas such as air or nitrogen, or a cooling method using a liquid miscible with the organic solvent used in the polyethylene solution, or a liquid such as water that is difficult to be miscible with the organic solvent used in the polyethylene solution.

The discharge-molded product is preferably deformed at a magnification of 1.1 to 100 times until it is cooled and solidified into a polyethylene fibrous material. The deformation magnification is more preferably 2.0 times or more and 80 times or less, and still more preferably 5.0 times or more and 50 times or less. The time required for deformation is preferably set to be within 3 minutes. More preferably within 2 minutes, and still more preferably within 1 minute. If the time required for deformation exceeds 3 minutes, the chains of the polyethylene molecules constituting the polyethylene fiber material may be loosened, and it may be difficult to obtain a polyethylene fiber having high strength and high elastic modulus. In the step of spinning the polyethylene solution to obtain the polyethylene fiber, a part of the solvent contained in the polyethylene fiber may be removed.

Subsequently, the obtained polyethylene fibrous material (undrawn yarn) is heated and drawn several times (drawing step). The stretching step may be 1-step stretching or a multi-step stretching of 2 or more steps. From the viewpoint of enhancing the strength of the polyethylene fiber, it is preferable to conduct multi-stage drawing in 2 or more stages. In the present specification, the term "polyethylene fibrous material" means a polyethylene fibrous material which has been stretched to a predetermined stretch ratio after a spinning step.

In the stretching step, the polyethylene fibrous material is heated by a method not particularly limited, and may be heated by using an inert gas such as air or nitrogen, or a medium such as water vapor or liquid, or may be heated by using a heating roll, a contact heater, or the like. The stretching temperature is preferably 110 ℃ or higher, more preferably 120 ℃ or higher, and still more preferably 130 ℃ or higher. The upper limit of the drawing temperature may be set to a range in which the fibers are not fused.

The draw ratio of the polyethylene fiber is preferably 8 times or more, more preferably 10 times or more, and further preferably 12 times or more, based on the total draw ratio by the roll. The upper limit of the draw ratio is not particularly limited, and a polyethylene fiber that can obtain desired strength, elongation, and elastic modulus can be determined.

When the polyethylene solution contains a volatile organic solvent, the organic solvent contained in the polyethylene fibers may be removed (desolventized) simultaneously with the stretching of the fibers. On the other hand, when the organic solvent constituting the polyethylene solution is nonvolatile, the nonvolatile organic solvent can be removed from the polyethylene fiber by extraction. For the extraction, for example, chloroform, benzene, trichlorotrifluoroethane (TCTFE), hexane, heptane, nonane, decane, ethanol, higher alcohols and other organic solvents can be used.

The desolvation step of removing the organic solvent from the polyethylene fibrous material may be performed in a step different from the drawing step, or may be performed simultaneously with the drawing step.

The production method of the present embodiment includes, in addition to the spinning step and the drawing step, the steps of: and a step of bringing the fibrous material of polyethylene into contact with a coloring liquid (coloring liquid contact step). In the coloring liquid contact step, a polyethylene fibrous material containing less than 20 mass% of an organic solvent is brought into contact with a coloring liquid containing a coloring material and an organic solvent and having a temperature of 0 ℃ or higher and less than 60 ℃. Thereby, the polyethylene fiber-like material can be provided with a coloring material.

The time for the coloring liquid contacting step is not limited as long as it is carried out on the polyethylene fibrous material having an organic solvent amount of less than 20% by mass. However, after the crystallization of the polyethylene is completed, it may be difficult to move the coloring material into the fibrous material, and therefore, it is preferable to perform the coloring liquid contact step before the final stretching in which the polyethylene fibrous material is stretched to a predetermined stretching ratio. Therefore, the coloring liquid contact step is preferably performed after the spinning step and before the stretching step, and when the stretching is performed in a plurality of steps of 2 or more, the coloring liquid contact step may be performed between the stretching steps, for example, if the stretching is performed in 2 steps, the stretching may be performed between the stretching steps of the 1 st step and the 2 nd step.

The amount of the organic solvent (residual solvent amount) contained in the polyethylene fiber is preferably 18% by mass or less, more preferably 15% by mass or less, preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 3% by mass or more. It is considered that the coloring material is easily moved to the inside of the polyethylene fiber before the solvent is completely removed, and therefore, the coloring material is present in the core portion of each fiber. Therefore, from the viewpoint of a deep color and uniform coloring, the polyethylene fiber is preferably subjected to the coloring liquid contact step in a state of containing a certain amount of residual solvent. However, the amount of the residual solvent is too large or too small, and tends to inhibit the migration of the coloring material into the fibrous material. When the amount of the residual solvent is too large, it is recommended to perform the solvent removal before the coloring liquid contact step, and the amount of the residual solvent is set to the above range in advance.

As the organic solvent contained in the coloring liquid, an organic solvent exemplified in the preparation of a polyethylene solution or an organic solvent for extraction exemplified in the solvent removal step can be used. When the organic solvent used for the preparation of the polyethylene solution is used, it is not necessary to change the conditions of the desolvation step depending on the kind of the solvent, and it is not necessary to separate the solvent recovered after the desolvation step for each solvent, which is preferable.

As the coloring material, the above coloring material is preferably used. More preferably an oil soluble dye or a disperse dye. The concentration of the coloring material in the coloring liquid can be adjusted so that the coloring material is contained in the colored polyethylene fiber in an amount of 0.2 to 5 mass%, and generally, the concentration of the coloring material in the coloring liquid is preferably 1 to 28 mass%. More preferably 1.5% by mass or more and 25% by mass or less, and still more preferably 2% by mass or more and 23% by mass or less. If the concentration of the coloring material is too low, it may be difficult to color a deep color, and if the concentration of the coloring material is too high, an excessive amount of the coloring material may remain on the fiber surface, which may undesirably decrease the color fastness of the polyethylene fiber.

The temperature of the coloring liquid is 0 ℃ or higher and less than 60 ℃. More preferably 5 ℃ or higher, still more preferably 8 ℃ or higher, still more preferably 10 ℃ or higher, preferably 50 ℃ or lower, and still more preferably 40 ℃ or lower. The temperature of the polyethylene fiber in contact with the coloring liquid is preferably 50 ℃ or lower, more preferably 45 ℃ or lower, and still more preferably 40 ℃ or lower. The lower limit of the temperature of the polyethylene fiber is not limited, and generally, it is preferably room temperature or higher. The temperature of the polyethylene fiber can be measured by a non-contact thermometer such as an infrared thermometer.

When the temperature of the coloring liquid is too high, the organic solvent evaporates rapidly, and only the coloring material remains on the surface of the polyethylene fiber, and it tends to be difficult to move the coloring material into the inside of the polyethylene fiber. In the above case, there is a concern that the surrounding members are contaminated in the subsequent step, and the coloring material may fall off from the product using the obtained polyethylene fiber to cause contamination. Further, in order to solve the above problem, a step of cleaning the dye attached to the surface is required, and there is a concern that the work efficiency is lowered. In addition, when the temperature of the coloring liquid is too high, the temperature of the polyethylene fiber material in contact therewith rises, and the influence on the tension applied to the polyethylene fiber material in the heat treatment step and the stretching step performed after the coloring liquid contact step becomes large, and as a result, there is a fear that unevenness in fineness and strength (yarn unevenness) may occur. In particular, when the stretching step is performed after the coloring liquid contact step, if the temperature of the polyethylene fibrous material is too high, the stretching point is not fixed, and there is a fear that stretching unevenness occurs.

Even if the temperature of the polyethylene fiber is sufficiently low and the temperature of the coloring liquid is high, the crystal structure formed in the polyethylene fiber when the polyethylene fiber is in contact with the coloring liquid may be disintegrated, resulting in uneven coloring. If the temperature of the coloring liquid and the temperature of the polyethylene fiber are within the above ranges, the above problems are less likely to occur, and therefore, the temperature is preferable.

The method of contacting the polyethylene fiber with the coloring liquid is not particularly limited as long as the coloring material can be applied to the polyethylene fiber, and various methods can be employed. Specific contact methods include: a method of contacting the polyethylene fiber-like material with the coloring liquid by guiding Oiling (Guide Oiling); a method of bringing a polyethylene fibrous material into contact with the surface of a rotating roller to which a coloring liquid is adhered; a method of spraying a coloring liquid to a running polyethylene fiber; and a method of contacting the polyethylene fibrous material with the coloring liquid by passing the polyethylene fibrous material through a bath of the coloring liquid. When the polyethylene solution contains a nonvolatile organic solvent (e.g., paraffin), the polyethylene fiber may be contacted with the coloring liquid by passing the polyethylene fiber through an extraction bath as the extraction bath, which is a coloring liquid obtained by dissolving the coloring material in the extraction solvent used in the solvent removal step.

The amount of the coloring liquid added to the polyethylene fibrous material is preferably in the range of 0.1 to 15% by mass relative to the polyethylene fibrous material. More preferably 0.5% by mass or more, further preferably 1% by mass or more, further preferably 12% by mass or less, and further preferably 8% by mass or less. When the amount of the coloring liquid is too small, there is a fear that coloring to a deep color is difficult, while when the amount of the coloring liquid is too large, an excessive coloring material remains on the fiber surface, and color fastness is deteriorated, and there is a fear that the coloring material is peeled off from the fiber during the process to contaminate peripheral members.

In the coloring liquid contacting step, the amount of the organic solvent contained in the polyethylene fibrous material may increase. However, when an excessive amount of organic solvent is present in the polyethylene fiber, the crystal structure is likely to be loosened, or the fiber is likely to slip on the stretching roll, and as a result, uniform stretching becomes difficult, and variation in fineness and strength is likely to occur. Therefore, the amount of the organic solvent contained in the polyethylene fiber after contact with the coloring liquid (the total amount of the organic solvent contained in the polyethylene fiber supplied to the coloring liquid contact step and the amount of the organic solvent added in the coloring liquid contact step) is less than 25% by mass, preferably 20% by mass or less, and more preferably 18% by mass or less. The lower limit of the amount of the organic solvent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1.0% by mass or more.

The coloring liquid contacting step is preferably carried out while applying a tension of 0.05cN/dtex or more and 3cN/dtex or less to the polyethylene fibrous material. More preferably 0.1cN/dtex and 1cN/dtex below, further preferably 0.2cN/dtex and 0.8cN/dtex below. When the tension applied to the polyethylene fiber is too small, it is difficult to stably run the polyethylene fiber, and there is a fear that the variation occurs and the unevenness in the application of the coloring material occurs. On the other hand, if the tension is too high, the polyethylene fibrous materials are in a bundled state, and the coloring liquid may hardly penetrate into the respective fibrous materials. In the above case, not only the uniformity of dyeing of the monofilaments is impaired, but also a large amount of coloring material remains on the surface of the polyethylene fibrous material, and as a result, the color fastness may be lowered.

In the present embodiment, a heat treatment step (heat treatment step) of heating the polyethylene fibrous material to which the coloring liquid has been applied at 110 ℃ or higher for 10 seconds or longer is performed. This promotes permeation of the coloring liquid into the polyethylene fiber, and facilitates migration of the coloring material to the core of the polyethylene fiber. As a result, a colored polyethylene fiber having a deep color and further improved color fastness can be obtained. This is considered to be because the heat treatment step is performed to perform the drawing step in a state where the coloring material is present inside (core portion) the polyethylene fiber, and the coloring material can be taken into the inside (core portion) of the polyethylene fiber by the polyethylene crystal generated by the drawing.

The heat treatment step may be performed at any time after the coloring liquid contact step. The heat treatment step may be performed alone or simultaneously with the stretching step. When the heat treatment step and the stretching step are performed simultaneously, the movement of the coloring material into the polyethylene fibrous material by the permeation of the coloring liquid and the crystallization of the polyethylene by the stretching can be performed simultaneously. In addition, when the heat treatment step and the stretching step are separately performed, the heat treatment step allows the stretching step to be performed after the coloring material has moved into the polyethylene fiber, and thus the color fastness can be further improved. The heat treatment step and the stretching step are preferably performed simultaneously.

The heating temperature is preferably 120 ℃ or higher, more preferably 130 ℃ or higher. The upper limit of the heating temperature is preferably a temperature at which breakage does not occur due to fusion, that is, a melting point of the polyethylene single fibers or less.

The heating method is not particularly limited, and for example, a known method such as hot air, hot roll, radiation plate, steam jet, hot pin, or the like can be used. In addition, from the viewpoint of minimizing contamination by the coloring material, a non-contact heating method using hot air, a radiation plate, steam jet, or the like is preferably employed.

The heating time is preferably 10 seconds or more, more preferably 12 seconds or more, and further preferably 15 seconds or more. The upper limit of the heating time is not particularly limited, and is, for example, preferably 150 seconds or less, more preferably 120 seconds or less, and further preferably 100 seconds or less. When the heat treatment step is performed alone, the heat treatment step and the stretching step are preferably performed within the above ranges.

The heat treatment step is preferably performed while applying tension to the polyethylene fibrous material. The tension applied to the polyethylene fiber is preferably 0.8cN/dtex to 6.5 cN/dtex. More preferably 1cN/dtex or more, further preferably 2cN/dtex or more, more preferably 6cN/dtex or less, further preferably 5cN/dtex or less.

The tension in the above range is applied in the heat treatment step, whereby the molecular chains of the polyethylene are stretched to cause a capillary phenomenon, and the permeation of the coloring liquid into the inside of the fibrous material is further promoted, which is preferable. When the tension in the heat treatment step is too small, the capillary phenomenon may not be easily generated. On the other hand, if the tension is too high, fuzz or the like occurs, and there is a fear that it is difficult to obtain a polyethylene fiber having a small variation in fineness or strength.

In the stretching step after the heat treatment step or simultaneously with the heat treatment step, the polyethylene fibrous material is preferably stretched at a magnification of at least 2 times. More preferably 2.5 times or more. As an upper limit, it is preferable to increase the draw ratio as much as possible for the purpose of increasing the strength, but if it is too high, the occurrence of yarn breakage or fuzz may be observed. Therefore, the stretch ratio is preferably 30 times or less.

In general, in the production of high-strength polyethylene, drawing is performed at a high draw ratio in order to increase the strength of the fiber. However, when the polyethylene fiber is brought into contact with a coloring liquid having a high temperature before the stretching step, the polyethylene fiber is softened in the stage of feeding to the stretching step, and therefore, when the high-magnification stretching is performed in this state, the stretching point is not fixed, and unevenness in fineness and strength may occur. Therefore, the stretching ratio in the stretching step after the heat treatment step or simultaneously with the heat treatment step is preferably within the above range.

[ embodiment 2]

the color fastness to rubbing is 3-grade or higher in both dry and wet states, and the acid value is 0.1mgKOH/g or higher and 50mgKOH/g or lower.

The colored polyethylene fiber of the present embodiment is colored in a dark color, and the L value obtained when the colored polyethylene fiber or a processed product obtained from the colored polyethylene fiber is measured by CIE-la-b color difference measurement is 80 or less. Smaller values of L indicate more colored polyethylene fibers. Therefore, the value of L must be 80 or less, preferably 75 or less, more preferably 70 or less, and still more preferably 65 or less. The lower limit of the L value is not particularly limited.

Coefficient of variation (%) in tensile strength is the standard deviation of tensile strength/average value of tensile strength × 100 (formula 1)

The colored polyethylene fiber preferably has an initial elastic modulus of 500cN/dtex or more and 2000cN/dtex or less. The initial modulus of elasticity is more preferably 600cN/dtex or more, and still more preferably 700cN/dtex or more. Further, 1600cN/dtex or less is more preferable, and 1400cN/dtex or less is even more preferable. If the initial elastic modulus is too high, it is difficult to form a polyethylene fiber into a rope or a braid during the molding process, and it is likely that a monofilament is cut.

The fineness of the monofilament constituting the colored polyethylene fiber is preferably 1dtex or more and 80dtex or less. When the single fiber fineness exceeds 80dtex, the polyethylene fiber becomes hard and it is difficult to improve the strength. Preferably 70dtex or less, more preferably 60dtex or less. In addition, fibers having a fiber size of less than 1dtex may be easily fluffed during drawing in the production process thereof or during actual use of polyethylene fibers. Preferably 2dtex or more, more preferably 5dtex or more.

In addition, the variation in fineness (coefficient of variation in total fineness) of the colored polyethylene fiber is preferably 10% or less. When the fineness unevenness exceeds 10%, not only the strength unevenness is liable to occur, but also the coloring unevenness is liable to occur due to the fluctuation of the fineness, and the color tone of the appearance may fluctuate, but when the fineness is not more than 10%, such a problem is not liable to occur, and therefore, it is preferable. The fineness unevenness is more preferably 6% or less, and still more preferably 5% or less.

The colored polyethylene fibers comprise a coloring material. As the coloring material, an organic coloring material is preferable, and particularly, it is preferable to use: a coloring material having an affinity with a polyolefin having a hydrophilic group at one terminal. This is because an emulsion can be formed by adding a polyolefin having a hydrophilic group at one end to a solvent for an organic coloring material, and water can be used as the solvent. This will be further explained in the following paragraphs. By using water in the solvent, the environmental load at the time of production and the environmental load of the product can be suppressed.

Examples of such coloring materials include oil-soluble dyes, disperse dyes, acid dyes, and cationic dyes. Among them, oil-soluble dyes and disperse dyes are preferable because they have good compatibility with polyolefins having a hydrophilic group at one end and can easily realize colored polyethylene fibers having a dark color. Examples of preferable oil-soluble dyes include c.i. solvent yellow 2 (hereinafter, referred to as "c.i. solvent yellow") 6, 14, 15, 16, 19, 21, 33, 56, 61, 80, c.i. solvent orange 1 (hereinafter, referred to as "c.i. solvent orange"), 2, 5, 6, 14, 37, 40, 44, 45, c.i. solvent red 1 (hereinafter, referred to as "c.i. solvent red"), 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, c.i. solvent violet 8 (hereinafter, referred to as "c.i. solvent violet"), 13, 14, 21, 27, c.i. solvent blue 2 (hereinafter, referred to as "c.i. solvent blue") 11, 12, 25, 58, 36, 55, 73, c.i. solvent green 3, and the like. Examples of the disperse dye include c.i. disperse red 4 (hereinafter, referred to as "c.i. disperse red"), 5, 11, 17, 60, 74, 75, 86, 91, 92, 152, 153, 167, 179, 200, 221, 302, a disperse dye classified as c.i. disperse black, c.i. disperse orange 3 (hereinafter, referred to as "c.i. disperse orange"), 13, 25, 31, 37, 45, 61, 76, a disperse dye classified as c.i. disperse gray, c.i. disperse yellow 3 (hereinafter, referred to as "c.i. disperse yellow"), 5, 42, 49, 79, 82, 104, 134, 149, 198, 211, 241, a disperse dye classified as c.i. disperse green, c.i. disperse violet 1 (hereinafter, referred to as "c.i. disperse violet"), 3, 28, 43, a disperse dye classified as c.i. disperse brown, c.i. disperse blue 1 (hereinafter, referred to as "c.i. disperse blue 1"), 106, 60, 165, 183, 257, 360, 183, and the like. These coloring materials may be used alone, or a plurality of coloring materials having different hues may be used in combination.

The acid value of the colored polyethylene fiber is preferably 0.1mgKOH/g to 50mgKOH/g, more preferably 0.5mgKOH/g to 30mgKOH/g, and still more preferably 1.0mgKOH/g to 10 mgKOH/g. In the present embodiment, the acid value of the colored polyethylene fiber has an influence on the polyolefin having a hydrophilic group at one terminal added to the solvent of the coloring material of the organic substance, and as described later in detail, when the acid value of the colored polyethylene fiber is less than 0.1mgKOH/g, a polyethylene fiber having high fastness cannot be obtained, which is not preferable. On the other hand, an acid value exceeding 50mgKOH/g is not preferable because the fastness is also deteriorated.

Next, the manufacturing method of the present embodiment will be described. In this embodiment, a coloring liquid used for coloring is different from that of embodiment 1, but a colored polyethylene fiber is basically produced by the same production method as that of embodiment 1. Therefore, the same contents in the steps described in embodiment 1 will not be described.

The production method of the present embodiment includes, in addition to the spinning step and the drawing step, the steps of: and a step of bringing the fibrous material of polyethylene into contact with a coloring liquid (coloring liquid contact step). In the coloring liquid contact step, the polyethylene fibrous material is contacted with a coloring liquid which contains a coloring material and a polyolefin having a hydrophilic group at one end and has a temperature of 0 ℃ or more and less than 60 ℃. Thereby, the polyethylene fiber-like material can be provided with a coloring material. The coloring liquid contains a coloring material and a polyolefin having a hydrophilic group at one end, and is preferably dispersed in water or in an emulsified state.

As the polyolefin having a hydrophilic group at one end, it is preferable to add a low molecular weight polyethylene having an acid value of not less than 1mgKOH/g and not more than 150mgKOH/g to the coloring liquid.

The molecular weight of the polyethylene added to the coloring liquid (hereinafter, added polyethylene) is preferably 500 to 20000. When the molecular weight is less than 500, the melting point becomes low, and the additive polyethylene may bleed out from the product when the product using the colored polyethylene fiber is used, which is not preferable. On the other hand, when the molecular weight of the polyethylene added exceeds 20000, the polyethylene added does not penetrate into the fiber, and therefore, it is not preferable.

The acid value of the polyethylene added is 1mgKOH/g to 150mgKOH/g, more preferably 3mgKOH/g to 120mgKOH/g, and still more preferably 5mgKOH/g to 100 mgKOH/g. When the acid value is less than 1mgKOH/g, the affinity with the coloring material becomes low, and a polyethylene fiber having high fastness cannot be obtained, which is not preferable. On the other hand, when the acid value exceeds 150mgKOH/g, the affinity between the polyethylene fiber and the added polyethylene becomes low, and therefore, the polyethylene fiber adheres to the polyethylene fiber in the middle of the below-described yarn-making step, and when the polyethylene fiber penetrates into the fiber, the penetration into the fiber becomes slow. As a result, the coloring material stays on the surface of the fiber, and thus the fastness of the fiber is deteriorated, which is not preferable.

Thus, by adding a polyethylene having a functional group terminal which has a low molecular weight and an acid value of 1mgKOH/g or more and 150mgKOH/g or less to the coloring liquid, a colored polyethylene fiber having an acid value of 0.1mgKOH/g or more and 50mgKOH/g or less can be obtained.

The melting point of the polyethylene added is preferably 80 ℃ or higher. When the melting point is less than 80 ℃, polyethylene exudes from the product during use of the product, which is not preferable. The method comprises the following steps: the additive polyethylene added to the coloring liquid is added so as to be compatible with the coloring material in the coloring liquid and to form an emulsion shape. The solvent in this case is preferably water. As described above, by using water in the solvent, the environmental load at the time of production and the environmental load of the product can be suppressed, and the fiber considering the environment and ecosystem can be produced.

The time for the coloring liquid contacting step is not limited as long as it is carried out on the polyethylene fibrous material. However, since it is sometimes difficult to move the coloring material into the fibrous material after the crystallization of the polyethylene is completed, it is preferable to perform the coloring liquid contact step before the final stretching in which the polyethylene fibrous material is stretched to a predetermined stretching ratio. Therefore, the coloring liquid contact step is preferably performed after the spinning step and before the stretching step, and when the stretching is performed in a plurality of steps of 2 or more, the coloring liquid contact step may be performed between the stretching steps, for example, in the case of 2-step stretching, the coloring liquid contact step may be performed between the stretching steps of the 1 st step and the 2 nd step.

When the temperature of the coloring liquid is too high, when the coloring material is dispersed in water, the water evaporates rapidly, and only the coloring material remains on the surface of the polyethylene fiber, and it tends to be difficult to move the coloring material into the inside of the polyethylene fiber. In the above case, there is a concern that the surrounding members are contaminated in the subsequent step, and the coloring material may fall off from the product using the obtained polyethylene fiber to cause contamination. Further, in order to solve the above problem, a step of cleaning the dye attached to the surface is required, and there is a concern that the work efficiency is lowered. In addition, when the temperature of the coloring liquid is too high, the temperature of the polyethylene fiber material in contact therewith rises, and the influence on the tension applied to the polyethylene fiber material in the heat treatment step and the stretching step performed after the coloring liquid contact step becomes large, and as a result, there is a fear that unevenness in fineness and strength (yarn unevenness) may occur. In particular, when the stretching step is performed after the coloring liquid contact step, if the temperature of the polyethylene fibrous material is too high, the stretching point is not fixed, and there is a fear that stretching unevenness occurs.

The method of contacting the polyethylene fiber with the coloring liquid is not particularly limited as long as the coloring material can be applied to the polyethylene fiber, and various methods can be employed. Specific contact methods include: a method of contacting the polyethylene fibrous material with the coloring liquid by introducing oil; a method of bringing a polyethylene fibrous material into contact with the surface of a rotating roller to which a coloring liquid is adhered; a method of spraying a coloring liquid to a running polyethylene fiber; and a method of passing and contacting the polyethylene fibrous material in a bath of the coloring liquid. When the polyethylene solution contains a nonvolatile organic solvent (e.g., paraffin), the polyethylene fiber may be contacted with the coloring liquid by passing the polyethylene fiber through an extraction bath as the extraction bath, which is a coloring liquid obtained by dissolving the coloring material in the extraction solvent used in the solvent removal step.

The amount of the coloring liquid added to the polyethylene fibrous material is preferably in the range of 0.1 to 15% by mass relative to the polyethylene fibrous material. More preferably 0.5% by mass or more, further preferably 1% by mass or more, further preferably 12% by mass or less, and further preferably 8% by mass or less. When the amount of the coloring liquid is too small, there is a fear that coloring to a deep color is difficult, while when the amount of the coloring liquid is too large, an excessive coloring material remains on the fiber surface, and color fastness is deteriorated, and further, the coloring material is peeled off from the fiber during the process, and there is a fear that peripheral members are contaminated.

When tension is applied to the polyethylene fibrous material in the heat treatment step, the molecular chains of the polyethylene are stretched to cause a capillary phenomenon, and the permeation of the coloring liquid into the inside of the fibrous material is further promoted, which is preferable. When the tension in the heat treatment step is too small, the capillary phenomenon may not be easily generated. On the other hand, if the tension is too high, fuzz or the like occurs, and there is a fear that it is difficult to obtain a polyethylene fiber having a small variation in fineness or strength.

In general, in the production of high-strength polyethylene, drawing is performed at a high draw ratio in order to increase the strength of the fiber. However, when the polyethylene fiber-like material is brought into contact with a coloring liquid having a high temperature before the stretching step, the polyethylene fiber-like material is softened in the stage of being supplied to the stretching step, and therefore, when the high-magnification stretching is performed in this state, the stretching point is not fixed, and there is a fear that unevenness occurs in fineness and strength. Therefore, the stretching ratio in the stretching step after the heat treatment step or simultaneously with the heat treatment step is preferably within the above range.

The colored polyethylene fiber of the present embodiment desirably has a residual solvent concentration after the heat treatment and drawing treatment of 1000ppm or less. When the residual solvent concentration exceeds 1000ppm, the influence on the environment and ecosystem at the time of production and use of the product becomes large, which is not preferable.

[ embodiment 3]

the color fastness to rubbing is 3-grade or higher in both dry and wet states, and the surfactant contains a surfactant having an HLB value (Hydrophile-Lipophile Balance) of from 0.4% to 5.0% of 7.0 to 14.0.

The colored polyethylene fiber of the present embodiment is colored in a dark color, and the L value obtained when the colored polyethylene fiber or a processed product obtained from the colored polyethylene fiber is measured by CIE-la-b color difference measurement is 80 or less. Smaller values of L indicate more colored polyethylene fibers. Therefore, the value of L must be 80 or less, and is preferably 75 or less, more preferably 70 or less, and still more preferably 65 or less. The lower limit of the L value is not particularly limited.

The colored polyethylene fiber of the present embodiment preferably has a tensile strength of 18cN/dtex or more. The tensile strength is more preferably 20cN/dtex or more, and still more preferably 25cN/dtex or more. The upper limit of the tensile strength is not particularly limited, and it is technically and industrially difficult to obtain a polyethylene fiber having a tensile strength of more than 60 cN/dtex.

The colored polyethylene fibers comprise a coloring material. As the coloring material, an organic coloring material is preferable, and particularly, it is preferable to use: a dye having an affinity with a surfactant. This is because the surfactant and the coloring material form an emulsion by adding the surfactant to the solvent of the coloring material of the organic substance, and therefore, water can be used as the solvent. This will be further explained in the following paragraphs. By using water in the solvent, the environmental load at the time of production and the environmental load of the product can be suppressed.

Examples of such coloring materials include oil-soluble dyes, disperse dyes, acid dyes, and cationic dyes. Among them, oil-soluble dyes and disperse dyes are preferable because they have good compatibility with surfactants and can easily realize polyethylene fibers colored in a deep color. Examples of preferable oil-soluble dyes include c.i. solvent yellow 2 (hereinafter, referred to as "c.i. solvent yellow") 6, 14, 15, 16, 19, 21, 33, 56, 61, 80, c.i. solvent orange 1 (hereinafter, referred to as "c.i. solvent orange"), 2, 5, 6, 14, 37, 40, 44, 45, c.i. solvent red 1 (hereinafter, referred to as "c.i. solvent red"), 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, c.i. solvent violet 8 (hereinafter, referred to as "c.i. solvent violet"), 13, 14, 21, 27, c.i. solvent blue 2 (hereinafter, referred to as "c.i. solvent blue") 11, 12, 25, 58, 36, 55, 73, c.i. solvent green 3, and the like. Examples of the disperse dye include c.i. disperse red 4 (hereinafter, referred to as "c.i. disperse red"), 5, 11, 17, 60, 74, 75, 86, 91, 92, 152, 153, 167, 179, 200, 221, 302, a disperse dye classified as c.i. disperse black, c.i. disperse orange 3 (hereinafter, referred to as "c.i. disperse orange"), 13, 25, 31, 37, 45, 61, 76, a disperse dye classified as c.i. disperse gray, c.i. disperse yellow 3 (hereinafter, referred to as "c.i. disperse yellow"), 5, 42, 49, 79, 82, 104, 134, 149, 198, 211, 241, a disperse dye classified as c.i. disperse green, c.i. disperse violet 1 (hereinafter, referred to as "c.i. disperse violet"), 3, 28, 43, a disperse dye classified as c.i. disperse brown, c.i. disperse blue 1 (hereinafter, referred to as "c.i. disperse blue 1"), 106, 60, 165, 183, 257, 360, 183, and the like. These coloring materials may be used alone, or a plurality of coloring materials having different hues may be used in combination.

The amount of the surfactant contained in the colored polyethylene fiber is preferably 0.4% or more and 5.0% or less, more preferably 0.4% or more and 3% or less, and further preferably 0.4% or more and 1% or less. The content of the surfactant in the colored polyethylene fiber particularly affects the surfactant added to the solvent of the coloring material used for coloring in the production process. When the content of the surfactant in the colored polyethylene fiber is less than 0.4%, dispersion of the coloring material in a water solvent is difficult, and if dispersion is possible, the coloring liquid adheres to the polyethylene fiber in the middle of the yarn-making step described later, and when the coloring liquid penetrates into the fiber, the penetration into the fiber becomes slow. As a result, the coloring material stays on the surface of the fiber, and thus, the fastness is deteriorated, which is not preferable. On the other hand, if the surfactant content in the colored polyethylene fiber exceeds 5.0%, aggregation of the coloring material contained in the coloring liquid occurs, or if coloring is possible, fluctuation occurs due to the influence of the surfactant excessively adhering to the fiber surface. This is not preferable because the surface smoothness and fastness of the fiber surface when forming a fiber product and the quality of the processed product during handling are impaired.

The HLB value (Hydrophile-Lipophile Balance) of the surfactant contained in the colored polyethylene fiber is preferably 7.0 or more and 14.0 or less. If the HLB value is less than 7, it is not preferable because it is difficult to form a surfactant into an aqueous dispersion when a coloring liquid is applied to the polyethylene fiber. Further, when the HLB value exceeds 14, the solubility of the surfactant in water is good, but the solubility of the colorant is poor, which is not preferable.

The surfactant used for the colored polyethylene fiber of the present embodiment is preferably a higher alcohol-based ethylene oxide adduct of a nonionic surfactant, such as a polyoxyalkylene alkyl ether, polyoxyethylene behenyl ether, or polyoxyethylene stearyl ether.

Next, the manufacturing method of the present embodiment will be described. In this embodiment, a coloring liquid used for coloring is different from that of embodiment 1, and a colored polyethylene fiber is produced by basically the same production method as that of embodiment 1. Therefore, the same contents in the steps described in embodiment 1 will not be described.

The method for producing a colored polyethylene fiber according to the present embodiment includes, in addition to the spinning step and the drawing step, the steps of: and a step of bringing the fibrous material of polyethylene into contact with a coloring liquid (coloring liquid contact step). In the coloring liquid contact step, a polyethylene fibrous material containing less than 20 mass% of an organic solvent is brought into contact with a coloring liquid containing a coloring material, a surfactant having the above HLB value range, and water and having a temperature of 0 ℃ or higher and less than 60 ℃. Thereby, the polyethylene fiber-like material can be provided with a coloring material. The coloring liquid contains a coloring material and a surfactant having the above HLB value, and is preferably dispersed in water or emulsified.

In the method for producing a colored polyethylene fiber according to the present embodiment, the coloring liquid used in the coloring liquid contact step is preferably a method comprising: a coloring material, a surfactant and water are used to form an aqueous dispersion or emulsion shape, thereby being added to the polyethylene fiber. As the method of emulsion, any known method can be used as long as the state of the coloring liquid can be changed from W/O phase to O/W phase. For example, an emulsion-liquefied coloring liquid can be obtained by mixing a coloring material and a surfactant, stirring the mixture with a stirrer such as a homogenizer or a high-speed stirrer, and dripping a small amount of water little by little to gradually increase the liquid viscosity, immediately bringing the phase transition to a paste state, and further dripping water. In order to dissolve the coloring material, an appropriate amount of solvent may be added.

When the emulsion is produced, various amounts of the functional agent may be added within a range not interfering with the spinning step and the coloring step. Examples thereof include light stabilizers (ultraviolet absorbers, light stabilizers, etc.), antibacterial agents, smoothing agents, deodorants, and the like. The amount of the additive to be used is preferably 0.01 to 10 parts by mass per 100 parts by mass of the coloring liquid.

The HLB value is a value indicating the balance between hydrophilicity and hydrophobicity, and can be obtained by various calculation methods such as the griffin method and the davis method. For example, in the griffin method, the HLB value is 20 × (molecular weight of hydrophilic group)/(total molecular weight of surfactant), and it is known that when the HLB value is in the range of 8 to 18, it can be estimated to be a surfactant suitable for water dispersion or emulsion. For example, when the number of carbons of the polyoxyalkylene alkyl ether is 12 and the number of moles of ethylene oxide added is 10 (when the atomic weight of hydrogen is1, the atomic weight of carbon is 12, and the atomic weight of oxygen is 16), the total molecular weight of the surfactant is 625, the molecular weight of the hydrophilic group is 396, and the HLB value is 20 × (440/625) ═ 14.08.

The HLB value of the surfactant does not change even in the fiber after the coloring liquid including the surfactant is applied.

The HLB of the surfactant can be determined as a value roughly based on information of a known analytical method such as cobalt (II) tetrasulfate absorptiometry JIS1993, a hydrobromic acid decomposition method, a bismuth iodide salt method, a liquid chromatography mass spectrometry method, a gas chromatography mass spectrometry, a flow paraffin O/W test, and a flow paraffin W/O test (association of basic and stabilization and evaluation technical information of emulsions).

Specific examples of the surfactant of the higher alcohol ethylene oxide adduct used in the method for producing a colored polyethylene fiber according to the present embodiment include a trade name "Nonion S-207" (manufactured by nippon oil co., ltd., HLB value 10.7) and a trade name "nanoact CL-70" (manufactured by sanyo chemical industries, ltd., HLB value 11.5).

The coloring liquid contacting step is not limited as long as it is carried out on the polyethylene fibrous material. However, after the crystallization of the polyethylene is completed, it may be difficult to move the coloring material into the fibrous material, and therefore, it is preferable to perform the crystallization before the final stretching in which the polyethylene fibrous material is stretched to a predetermined stretching ratio. Therefore, the coloring liquid contacting step is preferably performed after the spinning step and before the drawing step, and when the drawing is performed in a plurality of steps of 2 or more, the drawing may be performed between the drawing steps, for example, if the drawing is performed in 2 steps, the drawing may be performed between the drawing steps of the 1 st step and the 2 nd step.

When the temperature of the coloring liquid is too high, when the coloring material is dispersed in water, the water evaporates rapidly, and only the coloring material remains on the surface of the polyethylene fiber, and it tends to be difficult to move the coloring material into the inside of the polyethylene fiber. In the above case, there is a concern that the surrounding members are contaminated in the subsequent step, and the coloring material may fall off from the product using the obtained polyethylene fiber to cause contamination. Further, in order to solve the above problem, a step of cleaning the coloring material adhering to the surface is required, and there is a concern that the work efficiency is lowered. In addition, when the temperature of the coloring liquid is too high, the temperature of the polyethylene fiber material in contact therewith rises, and the influence on the tension applied to the polyethylene fiber material in the heat treatment step and the stretching step performed after the coloring liquid contact step becomes large, and as a result, there is a fear that unevenness in fineness and strength (yarn unevenness) may occur. In particular, when the stretching step is performed after the coloring liquid contact step, if the temperature of the polyethylene fibrous material is too high, the stretching point is not fixed, and there is a fear that stretching unevenness occurs.

The colored polyethylene fiber of the present embodiment desirably has a residual solvent concentration after the heat treatment and drawing treatment of 1000ppm or less. When the residual solvent concentration exceeds 1000ppm, the influence on the environment and human upon the use of the product during the production becomes large, which is not preferable.

The colored polyethylene fibers described in embodiments 1 to 3 are colored in a dark color and have excellent color fastness to rubbing and/or solvent resistance, and therefore are suitable for use as materials such as braids, fishing lines, gloves, ropes, nets, fabrics, and woven fabrics. All filaments used in these applications may be used as the colored polyethylene fiber, and the colored polyethylene fiber may be used in a part thereof. For example, in the case of a braid, it is desirable to contain at least 1 colored polyethylene fiber.

Preferably, the strength of the fiber (multifilament) unwound from the braid is 15cN/dtex or more. More preferably 18cN/dtex or more, and further preferably 20cN/dtex or more. The upper limit of the fineness is the same as that of the colored polyethylene fiber.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples, and it goes without saying that the present invention can be carried out with appropriate modifications within a range that can meet the gist described above and below, and these are included in the scope of protection of the present invention. In the following, unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

First, a method for evaluating a colored polyethylene fiber (yarn) obtained in examples and the like of the subsequent stage will be described.

(1) Determination of color (CIE-L a b color system)

The measurement conditions were measured in accordance with JIS Z8781-42013. This was done using a SPECTROPHOTOMETER CM-3700D (manufactured by Konica Minolta Co., Ltd.) with a Datacolor Spectraflash model SF-300 colorimeter (Datacolor International) using a D65/10 degree light source.

The measurement samples were prepared as follows: the colored polyethylene fiber was wound around a stainless steel (SUS304) plate so as to form as few gaps as possible.

The measurement was carried out by using an International reference color measurement method published by "Commission International de L' Eclairage" (France, Paris) (International Society for Illumination/Lighting)) ("CIE") using a reference color coordinate of an L a b color space of mCIELLAB. "L" represents lightness coordinates, "a" represents red/green coordinates (+ a "represents red and-a" represents green), and "b" represents yellow/blue coordinates (+ b "represents yellow and-b" represents blue).

(2) Color fastness to rubbing

A sample was prepared according to JIS L0801 (2000). The color fastness to rubbing was tested on the samples in the dry state and the wet state using a rubbing tester type II (chemical vibration type) in accordance with JIS L0849 (2013). As a result, the color fastness was determined by a visual method using a gray scale for staining (JIS L0805 (2005)).

At least 1 piece of the colored polyethylene fiber as a sample was fixed to a sample stage of a chemical vibration type friction tester and measured. When the length of the fiber is sufficient, a plurality of fibers are aligned and fixed on a sample stage, and measurement is performed. Alternatively, a sample wound densely and rigidly around a rectangular cardboard having a size similar to the size of the sample stage may be produced in parallel with the longitudinal direction of the cardboard, and the sample may be measured, or may be measured in a state where a fabric is formed by tubular knitting or the like. When the sample is a fabric, it can be used as it is.

(3) Solvent resistance (measurement in examples 1-1 to 1-5, comparative examples 1-1 to 1-5, and reference examples 1-1 and 1-2)

The colored polyethylene fiber was immersed in acetone so as to be 0.1g/mL in a transparent glass container, and allowed to stand at room temperature (20 ℃ C.) for 24 hours. Acetone (blank acetone) used for dipping the colored polyethylene fiber and acetone obtained by dipping the colored polyethylene fiber and leaving the dipped colored polyethylene fiber for 24 hours were measured for transmittance in a wavelength range of 350 to 780nm by an ultraviolet-visible spectrophotometer (Hitachi, manufactured by Ltd., U-3210 type), and the integrated value T of transmittance in the above wavelength range was obtained from the obtained transmittance curve₀(acetone used for impregnation of blank and colored polyethylene fiber), T₁(acetone after impregnation of the colored polyethylene fiber), the solvent resistance was calculated by the following formula 2.

Solvent resistance (%) - (T)₁/T₀) X 100 (formula 2)

(4) Fineness of yarn, fineness unevenness of yarn

The polyethylene fibers were cut into 50cm pieces at 3 positions different in the longitudinal direction, and the weight thereof was measured, and the average value thereof was used to determine the fineness of the yarn. The fineness of the single yarn can be calculated from the fineness of the yarn.

The fineness unevenness in the longitudinal direction was measured by the following method. The weight of each of 10 colored polyethylene fibers was measured by cutting 10 pieces of the fibers continuously at 10cm intervals, and the fineness unevenness (coefficient of variation of total fineness) was determined by the following formula 3.

Fineness unevenness (%) ═ average value of fineness standard deviation/fineness x 100 (formula 3)

(5) Tensile strength, elongation and elastic modulus

Measured according to JIS L10138.5.1. The tensile strength and the elastic modulus were determined as follows: the strain-stress curve was measured under the conditions of a sample length of 200mm (length between chucks), an elongation rate of 100%/min, an atmosphere temperature of 20 ℃ and a relative humidity of 65% by using a "Tensilon universal material tester" manufactured by Orientec co., ltd., and the strength (cN/dtex) and the elongation (%) were calculated from the stress and the elongation at the breaking point, and the elastic modulus (cN/dtex) was calculated from a tangent line providing the maximum gradient in the vicinity of the origin of the curve, to obtain the strain-stress curve. The initial load applied to the polyethylene fiber during the measurement was 1/10(cN/dtex) in fineness. The average of 10 measurements was used for each value.

(6) Variation in tensile strength (coefficient of variation) of fiber in the longitudinal direction

The strength test was performed at any 10 positions in the longitudinal direction of the colored polyethylene fiber, and the Coefficient of Variation (CV) (%) of tensile strength was determined by the following (formula 1). The sample collection site is not particularly limited as long as it is collected from the same fiber (filament), and it may be collected continuously in the fiber longitudinal direction, or 1 sample may be collected and then the next sample may be collected at intervals.

(7) Intrinsic viscosity

The specific viscosities of the respective diluted solutions were measured in decalin at 135 ℃ using a Ubbelohde capillary viscosity tube, and the intrinsic viscosities were determined from extrapolated points of straight lines obtained by minimum 2-fold approximation of the viscosity-concentration curves to the origin. The intrinsic viscosity can be measured not only for the raw material polyethylene but also for the produced polyethylene fiber.

(8) Amount of organic solvent (measured in examples 1-1 to 1-5, comparative examples 1-1 to 1-5, reference examples 1-1 and 1-2 only)

From the spinning step and the coloring liquid contacting step, a polyethylene fibrous material (multifilament) was drawn out, the weight (weight before drying) was measured, and the drawn polyethylene fibrous material was vacuum-dried at a temperature at which the organic solvent was volatilized for 24 hours, and the weight (weight after drying) was measured again. From the obtained weight and the following formula, the amount of the organic solvent (residual solvent amount) contained in the polyethylene fibrous material was determined.

Residual solvent amount (%) - (weight before drying-weight after drying)/weight before drying × 100

(9) Residual volatile solvent concentration (measured in examples 2-1 to 2-4, comparative examples 2-1 to 2-6, and reference example 2-1 only)

The residual solvent concentration was measured by using a "gas chromatograph" manufactured by Shimadzu corporation. First, 10mg of polyethylene fiber was attached to a glass tube core at an inlet of a gas chromatograph, the inlet was heated to a temperature equal to or higher than the boiling point of the solvent, and the solvent generated by the heating was introduced into the column by purging with nitrogen. Subsequently, the column temperature was set to 40 ℃ and the solvent was trapped for 5 minutes. Then, the column temperature was increased to 80 ℃ and the measurement was started. The residual solvent concentration was determined from the obtained peak.

(10) Acid value of fiber (measured in examples 2-1 to 2-4, comparative examples 2-1 to 2-6, and reference example 2-1 only)

After 1 to 2g of a polyethylene fiber sample was dissolved in 20ml of hot xylene heated to 130 ℃, phenolphthalein was added, and the solution was titrated with 0.1mol/L potassium methyl alcohol to determine the acid value.

(11) The amount of surfactant in the fiber (measured in examples 3-1 to 3-7 and comparative examples 3-1 to 3-4 only)

The colored polyethylene fiber is extracted, separated and purified, and the amount of the surfactant remaining in the fiber is measured by a known method such as structural analysis such as NMR and LC/MS.

(example 1-1)

An ultrahigh molecular weight polyethylene having an intrinsic viscosity of 18.5dL/g and 98% of its repeating units was dispersed in decalin to prepare a dispersion having a polyethylene concentration of 8% by mass. The dispersion was heated at 190 ℃ in an extruder to form a solution, which was then discharged from a spinneret having an orifice diameter of 1.0mm and containing 30H at a nozzle face temperature of 180 ℃ and a discharge rate per hole of 2.0 g/min. The discharged filaments were deformed 8 times until they were solidified, and cooled in a water-cooling bath at 30 ℃ to obtain polyethylene fibers (undrawn filaments). The amount of the residual solvent in the undrawn yarn was 12% by mass.

Next, a coloring liquid (30 ℃) in which 20 mass% of c.i. solvent blue 58 was dissolved in decalin was attached by guided oil injection so as to have an attachment amount of 6 mass% with respect to the mass of the polyethylene fibrous material. The temperature of the polyethylene fiber material at the time of contact with the coloring liquid was 30 ℃, the tension was 1.2cN/dtex, and the amount of the organic solvent contained in the polyethylene fiber material after contact with the coloring liquid was 16.8 mass%.

Then, the polyethylene fibrous material was subjected to heat treatment in a hot air of nitrogen gas at 120 ℃ for 11 seconds while applying a tension of 3.7cN/dtex, and then subjected to stretching at the same temperature by 3 times (step 1). Thereafter, the polyethylene fiber material stretched in the 1-step was stretched 5-fold in an oven at 150 ℃ (step 2), and wound up. The intrinsic viscosity of the colored polyethylene fiber obtained in this case was 16 dL/g. The production conditions used in example 1-1 are shown in Table 1, and the physical properties of the obtained colored polyethylene fiber are shown in Table 2.

The resulting colored polyethylene fibers were color measured and found to have L value of 41.25, a value of 1.62, b value of-42.05. Next, the mixture was mixed in acetone at a bath ratio of 1: 20 (polyethylene fiber: acetone, mass ratio), left to stand at room temperature (20 ℃) for 24 hours, then taken out, and the color measurement was carried out in the same manner. The polyethylene fibers after acetone treatment had the following color tones: the values of L, a, and b are 42.10, 1.73, 41.06, respectively. Also, no change in color tone was observed in comparison with the polyethylene fiber before acetone treatment.

A method for examining the structure and content of the coloring material contained in the fiber will be described with reference to example 1-1. When different coloring materials are used, if an appropriate solvent or device is used depending on the coloring material, the structure of the coloring material contained in the fiber can be identified and the content can be determined in the same manner.

3g of the colored polyethylene fiber obtained in example 1-1 was subjected to Soxhlet extraction for 4 hours using 120mL of acetone as a solvent. Drying the extractive solution, dissolving the obtained residue 15mg in 0.6mL deuterated chloroform, and performing by using AVANCE500 prepared from BRUKER BIOSPIN¹And (4) determination of an H-NMR spectrum.

In addition, 1mg of the above residue was dissolved in 20mL of a methanol/chloroform mixed solvent (2/1 volume ratio), and precision mass measurement was performed by electrospray ionization using microOTOF manufactured by BRUKER DALTONICS.

From the result¹The results of the H-NMR spectrum and the accurate mass measurement confirmed that the polyethylene fiber of example 1-1 contained C.I. solvent blue 58 without causing decomposition or the like.

The content of the coloring material in the colored polyethylene fiber of example 1-1 can be determined as follows. The residue obtained in the Soxhlet extraction was dissolved in acetone to prepare a sample solution having a concentration of 10mg/L, and the UV-visible absorption spectrum was measured by a UV-visible spectrophotometer (for example, SolidSpec-3700 manufactured by Shimadzu corporation). Separately, acetone solutions of at least 3 kinds of c.i. solvent blue 58 having different concentrations were prepared, and the ultraviolet-visible absorption spectrum was measured in the same manner to prepare a calibration curve showing the relationship between the absorbance at the maximum absorption wavelength (440 nm in the case of c.i. solvent blue 58) at a wavelength of 350nm to 700nm and the solution concentration. Then, from the calibration curve and the measurement result of the sample (10 mg/L acetone solution of the residue), the amount of the coloring material contained in the polyethylene fiber can be determined. When a coloring material other than c.i. solvent blue 58 is used, an appropriate solvent or device may be used depending on the coloring material.

(examples 1 to 2)

Polyethylene fibers were produced by spinning and drawing under the same conditions as in example 1-1, except that 1.7% by mass of an antioxidant was added to the raw material polyethylene used in example 1-1. The intrinsic viscosity of the colored polyethylene fiber obtained in example 1-2 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained colored polyethylene fiber are shown in table 2.

(examples 1 to 3)

Polyethylene fibers were produced by spinning and drawing under the same conditions as in example 1-1, except that the temperature of the coloring liquid was changed to 45 ℃ and the drawing temperature in the drawing step of step 2 was changed to 148 ℃, and further, the conditions shown in table 1 were used. The intrinsic viscosity of the colored polyethylene fibers obtained in examples 1 to 3 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained colored polyethylene fiber are shown in table 2.

Since the coloring liquid had a higher temperature than that of example 1-1, tension relaxation occurred in the heat treatment step and the stretching step in step 1, but the physical properties were not significantly reduced.

(examples 1 to 4)

In the drawing step of step 1 after contact with the coloring liquid, the furnace length of the drawing furnace was increased to 130 ℃ for the heat treatment and drawing temperature (step 1) while keeping the drawing speed constant, and the polyethylene fiber was produced by spinning and drawing under the same conditions as in example 1-1 except that the conditions shown in Table 1 were used. The intrinsic viscosity of the colored polyethylene fibers obtained in examples 1 to 4 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained polyethylene fiber are shown in table 2.

The heat treatment time and the deformation time were longer than those of the other examples, and the tension was relaxed between the heat treatment and the drawing in step 1, but the physical properties of the polyethylene fiber were not much different from those of example 1-1. The polyethylene fibers of examples 1 to 4 were colored in a dark color (L × value 39.32) as compared with the polyethylene fibers of the other examples, but the amount of acetone extracted from the colored material was small, and the solvent resistance (95%) was excellent. This is presumably because, compared with the other examples, the heat treatment temperature after the coloring liquid contact was high and the heat treatment time was long, and therefore, the movement of the coloring material into the polyethylene fiber was promoted.

(examples 1 to 5)

In example 1-1, the polyethylene fiber (undrawn yarn) obtained in the spinning step and the coloring liquid were heat-treated in hot air of nitrogen at 120 ℃ for 11 seconds without being in contact with each other, and drawn at the same temperature at a draw ratio of 3 times (step 1). The coloring liquid (20 mass% C.I. solvent blue 58 decalin solution, 30 ℃) was attached to the polyethylene fiber material after the 1-step stretching by guided oil injection so that the amount of the attached coloring liquid was 6 mass% based on the mass of the polyethylene fiber material (residual solvent amount: 9 mass%). The polyethylene fiber material in contact with the coloring liquid was at a temperature of 30 ℃ and a tension of 0.5 cN/dtex.

Then, the polyethylene fiber material after the contact of the coloring liquid was heat-treated at 150 ℃ for 18 seconds (tension 4.5cN/dtex), and then stretched 5 times at the same temperature and wound up. The intrinsic viscosity of the colored polyethylene fibers obtained in examples 1 to 5 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained polyethylene fiber are shown in table 2.

Even if the drawing step of step 1 was followed by the coloring liquid contact step, the physical properties were not significantly different from those of example 1-1, and a colored polyethylene fiber colored in a deep color and having excellent color fastness and solvent resistance could be obtained.

Comparative example 1-1

The spinning and drawing were carried out under the same conditions as in example 1-1 except that the temperature of the coloring liquid in contact with the polyethylene fibrous material (undrawn yarn) obtained in the spinning step was changed to 140 ℃.

Comparative examples 1 and 2

A polyethylene fiber was obtained by spinning and drawing under the same conditions as in example 1-1 except that the temperature of the coloring liquid in contact with the polyethylene fibrous material (undrawn yarn) obtained in the spinning step was changed to 110 ℃ and the tension was changed to 0.02cN/dtex, the temperatures of the heat treatment step and the drawing step in step 1 were changed to 110 ℃, the draw ratio was changed to 5 times, and the drawing temperature in the drawing step in step 2 was changed to 145 ℃ and the draw ratio was changed to 4 times. The intrinsic viscosity of the colored polyethylene fiber obtained in comparative example 1-2 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained colored polyethylene fiber are shown in table 2.

The obtained colored polyethylene fiber had larger variations in fineness and strength than those of examples. This is considered to be because, in comparative example 1-2, since the temperature of the coloring liquid was too high, the undrawn yarn was softened at the time of contact with the coloring liquid, and the tension could not be maintained at a high level in the coloring liquid contact step, and since the drawing step of step 1 was performed in this state, the drawing point was not fixed, and it was difficult to obtain uniform drawing.

In addition, the polyethylene fibers were colored in a dark color, but both the color fastness to rubbing and the solvent resistance were inferior to those of the examples. This is presumably because, since the temperature of the coloring liquid is high, decalin as a solvent rapidly volatilizes from the coloring liquid adhering to the undrawn yarn, the concentration of the dye in the fiber surface becomes too high, and the movement of the coloring material into the undrawn yarn is less likely to occur.

Comparative examples 1 to 3

Colored polyethylene fibers were obtained by spinning and drawing under the same conditions as in example 1-1 except that the tension applied to the polyethylene fiber material at the time of contact with the coloring liquid was set to 0.9cN/dtex, the subsequent heat treatment was performed at 90 ℃ for 5 seconds and at a tension of 4.2cN/dtex, the draw ratio in the 1 st step was set to 2 times, and the draw temperature in the drawing step in the 2 nd step was set to 141 ℃ and the draw ratio was set to 2.5 times. The intrinsic viscosity of the colored polyethylene fibers obtained in comparative examples 1 to 3 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained colored polyethylene fiber are shown in table 2.

The obtained colored polyethylene fiber had poor color fastness to rubbing as compared with the colored polyethylene fibers of examples. This is considered to be because the temperature of the heat treatment after the coloring liquid contact step is low and the time is short, and therefore, it is difficult to promote the permeation of the coloring material into the inside of the fibrous material. This is also indicated by a solvent resistance of 64%.

In addition, the colored polyethylene fibers of comparative examples 1 to 3 had lower strength and elastic modulus than those of examples, and also had variations in strength and fineness. This is considered to be because the stretching temperature in step 1 is low, and therefore the stretching ratio cannot be increased in step 1 and step 2, and in addition, the stretching point is not fixed due to the influence of the coloring material and the solvent remaining on the surface of the fibrous material in a large amount, and the stretching cannot be performed homogeneously.

Comparative examples 1 to 4

Polyethylene fibers were obtained by spinning and drawing under the same conditions as in example 1-1, except that a coloring liquid (solvent: decalin) having a concentration of 30% by mass of a coloring material (c.i. solvent blue 58) was used and the amount of the coloring liquid added to the polyethylene fiber material was 20% by mass. The organic solvent contained in the polyethylene fibrous material after the coloring liquid contact step (the total amount of the organic solvent after the spinning step and the organic solvent derived from the coloring liquid) was 26 mass%. The intrinsic viscosity of the colored polyethylene fibers obtained in comparative examples 1 to 4 was 16 dL/g. The production conditions are shown in table 1, and the physical properties of the obtained polyethylene fiber are shown in table 2.

The polyethylene fibers obtained had a dark color, but had inferior color fastness and solvent resistance, and large variations in strength and fineness as compared with the examples. This is considered to be because the drawing step is passed in a state where an excessive coloring material is present on the surface of the fiber. Further, it is considered that the residual solvent amount contained in the polyethylene fibrous material after the coloring liquid contact step is large, and therefore, the stretching becomes uneven.

(reference examples 1-1 and comparative examples 1-5)

A colored polyethylene fiber was obtained by spinning and drawing in the same manner as in example 1-1, except that c.i. solvent blue 58 was added to the raw material polyethylene dispersion (polyethylene concentration 8 mass%) so that the concentrations thereof were 0.1 mass% (reference example 1-1) and 0.01 mass% (comparative example 1-5) with respect to the solvent, and the colored liquid contact step was not performed. However, in the drawing step of step 2 of reference example 1-1, since breakage occurred more when the draw ratio was set to 5 times, the draw ratio was set to 4 times. The intrinsic viscosity of the colored polyethylene fibers of reference examples 1 to 1 was 16dL/g, and the intrinsic viscosity of the colored polyethylene fibers of comparative examples 1 to 5 was 16 dL/g. The coloring material contained in the colored polyethylene fiber of reference example 1-1 was 1.2 mass%, and the coloring material contained in the colored polyethylene fiber of comparative example 5 was 0.12 mass%. The production conditions and physical properties are shown in tables 1 and 2, respectively.

The polyethylene fibers obtained in reference example 1-1 had low strength, elongation, and elastic modulus, and the fluctuations in strength and fineness within the fibers (filaments) were also larger than those of the polyethylene fibers of the examples. In reference example 1-1, since the coloring material was added to the raw material polyethylene dispersion liquid in the spinning stage, the coloring material may be present in a deep portion within the crystal structure of the polyethylene, but it functions as a foreign substance and it is difficult to increase the draw ratio. On the other hand, in comparative examples 1 to 5, the effect of foreign matter was reduced by decreasing the content of the coloring material, and polyethylene fibers having strength, elongation and elastic modulus of the same degree as those of examples could be obtained, but the L value was higher than 80 and was pale in color because of a small amount of the coloring material added.

Reference examples 1 to 2

Polyethylene fibers were produced in the same manner as in example 1-1, except that the undrawn yarn was not brought into contact with the coloring liquid. The colored polyethylene fibers of reference examples 1-2 had an intrinsic viscosity of 16 dL/g. The production conditions and physical properties are shown in tables 1 and 2, respectively.

[ Table 1]

The coloring liquid contacting step of examples 1 to 5 was performed after the stretching step of step 1.

In table 1, the organic solvent amount 1 represents the amount of the organic solvent contained in the polyethylene fiber supplied to the coloring liquid contact step, the organic solvent amount 2 represents the amount of the organic solvent contained in the polyethylene fiber after the coloring liquid contact step (the total amount of the organic solvent 1 and the organic solvent derived from the coloring liquid), and the yarn temperature represents the temperature of the yarn supplied to the coloring liquid contact step.

[ Table 2]

(example 2-1)

An ultrahigh molecular weight polyethylene having an intrinsic viscosity of 17.0dL/g and 98% of the repeating units thereof was dispersed in decalin to prepare a dispersion having a polyethylene concentration of 9% by mass. The dispersion was heated at 200 ℃ in an extruder to form a solution, and then discharged from a spinneret having an orifice diameter of 1.0mm and containing 30H at a nozzle face temperature of 180 ℃ and a discharge rate per hole of 2.0 g/min. The discharged filaments were deformed 8 times until they were solidified, and cooled in a water-cooling bath at 30 ℃ to obtain polyethylene fibers (undrawn filaments).

Next, using purified water as a solvent, a coloring liquid (30 ℃) obtained by forming c.i. solvent blue 35(10 mass%), an acid value of 20mgKOH, and a modified polyethylene (added polyethylene) having a molecular weight of 3000 (10 mass%) in water into an emulsion shape was brought into contact with the polyethylene fibrous material by a guided oil injection method, and the coloring liquid was attached so that an attachment amount was 1 mass% with respect to the mass of the polyethylene fibrous material. The temperature of the polyethylene fiber (filament temperature) at the time of contact of the coloring liquid was 30 ℃.

Subsequently, the polyethylene fiber material to which the coloring liquid was adhered was heat-treated in hot air at 100 ℃ under nitrogen for 15 seconds, and then stretched 4 times at the same temperature (step 1). Thereafter, the polyethylene fiber material stretched in the 1-step was stretched 4-fold in an oven at 150 ℃ (step 2) and taken up. The production conditions used in example 2-1 and the physical properties of the resulting colored polyethylene fiber are shown in Table 3.

(example 2-2)

Colored polyethylene fibers were produced in the same manner as in example 2-1, except that polyethylene having a molecular weight of 4000 and an acid value of 30mgKOH was used as the additive polyethylene to be added to the coloring liquid, and the drawing time in step 1 was set to 25 seconds. The production conditions used in example 2-2 and the physical properties of the resulting colored polyethylene fiber are shown in Table 3.

(examples 2 to 3)

Colored polyethylene fibers were produced in the same manner as in example 2-1, except that the polyethylene added to the coloring liquid had a molecular weight of 3000 and an acid value of 60mgKOH, and the drawing time in step 1 was set to 25 seconds and the drawing ratio in step 1 was set to 3.5 times. The production conditions used in examples 2 to 3 and the physical properties of the obtained colored polyethylene fiber are shown in table 3.

(examples 2 to 4)

Colored polyethylene fibers were produced in the same manner as in example 2-1, except that the additive polyethylene to be added to the coloring liquid was polyethylene having a molecular weight of 5000 and an acid value of 40mgKOH, and was used in an amount of 20% by mass, and the drawing time in step 1 was 25 seconds and the draw ratio in step 1 was 3.5 times. The production conditions used in examples 2 to 4 and the physical properties of the obtained colored polyethylene fiber are shown in table 3.

Comparative example 2-1

An ultrahigh molecular weight polyethylene having an intrinsic viscosity of 18.5dL/g and 96% of the repeating units being ethylene was dispersed in decalin to prepare a dispersion having a polyethylene concentration of 8% by mass. The dispersion was heated at 190 ℃ in an extruder to form a solution, which was then discharged from a spinneret having an orifice diameter of 0.8mm and containing 30H at a nozzle face temperature of 180 ℃ at a discharge rate of 2 g/min per hole. The discharged filaments were deformed by 16 times until they were solidified, and cooled in a water-cooling bath at 30 ℃ to obtain polyethylene fibers (undrawn filaments).

Next, a coloring liquid (30 ℃) in which 10 mass% of c.i. solvent blue 58 was dissolved in decalin was brought into contact with the polyethylene fibrous material by a guided oiling method, and was attached so that the amount of attachment was 1 mass% with respect to the mass of the polyethylene fibrous material. The temperature of the polyethylene fiber (filament temperature) at the time of contact of the coloring liquid was 30 ℃.

Subsequently, the polyethylene fiber was heat-treated in a hot air of nitrogen at 120 ℃ for 11 seconds, and then stretched 3 times at the same temperature (step 1). Thereafter, the polyethylene fiber material after the 1-step drawing was subjected to 5-fold drawing (step 2) in an oven at 150 ℃ and taken up. The production conditions used in comparative example 2-1 and the physical properties of the resulting colored polyethylene fiber are shown in Table 2.

Comparative examples 2 and 2

Colored polyethylene fibers were produced in the same manner as in comparative example 2-1, except that the colored solution (110 ℃ C.) having 15 mass% of C.I. solvent blue 35 dissolved in decalin was brought into contact with the polyethylene fibrous material by the guided oiling method and the stretching in step 2 was carried out in an oven at 135 ℃. The production conditions used in comparative example 2-2 and the physical properties of the resulting colored polyethylene fiber are shown in Table 4.

Comparative examples 2 to 3

Colored polyethylene fibers were produced in the same manner as in comparative example 2-1, except that c.i. solvent blue 35 was added to the same raw polyethylene dispersion as in comparative example 2-1 so that the concentration thereof became 0.05 mass%, and the undrawn yarn and the coloring liquid were not brought into contact with each other (dyeing was not performed). The production conditions employed in comparative examples 2 to 3 and the physical properties of the resulting colored polyethylene fiber are shown in Table 4.

Comparative examples 2 to 4

Colored polyethylene fibers were produced in the same manner as in comparative example 2-1, except that the colored polyethylene fiber was produced in the same manner as in comparative example 2-1, except that a coloring liquid in which 20 mass% of c.i. solvent blue 58 was dissolved in decalin was used, and after heat treatment was performed for 5 seconds in hot air of nitrogen at 90 ℃, stretching was performed at 2 times at the same temperature (step 1), and then the polyethylene fiber material after stretching in step 1 was stretched in an oven at 90 ℃. The production conditions employed in comparative examples 2 to 4 and the physical properties of the resulting colored polyethylene fiber are shown in Table 4.

Comparative examples 2 to 5

Colored polyethylene fibers were produced in the same manner as in comparative example 2-1, except that the polyethylene fibrous material was adhered using a coloring liquid in which 20 mass% of c.i. solvent blue 58 was dissolved in decalin in an amount of 12 mass% relative to the mass of the polyethylene fibrous material, and the stretching in step 2 was performed in an oven at 135 ℃. The production conditions employed in comparative examples 2 to 5 and the physical properties of the resulting colored polyethylene fiber are shown in Table 4.

Comparative examples 2 to 6

A coloring liquid was prepared using c.i. solvent blue 35(10 mass%) as a coloring material, using purified water as a solvent, and without adding polyethylene. The coloring liquid is not a homogeneous solution, but a state in which the coloring material is dispersed in water. Polyethylene fibers were produced in the same manner as in examples 2 to 4 except that this coloring liquid was used. However, the coloring material adheres only to the surface of the fiber, and cannot color the polyethylene fiber. The production conditions used in comparative examples 2 to 6 and the physical properties of the obtained polyethylene fibers are shown in Table 4.

(reference example 2-1)

Polyethylene fibers were produced in the same manner as in comparative example 2-1, except that the undrawn yarn was not brought into contact with the coloring liquid (dyeing was not performed) and that the drawing in step 1 was performed by 3.5 times. The production conditions used in reference example 2-1 and the physical properties of the obtained polyethylene fiber are shown in Table 4.

[ Table 3]

[ Table 4]

As is clear from tables 3 and 4, the concentration of the residual volatile solvent is overwhelmingly low and the environmental load is hardly caused in examples 2-1 to 2-4 in which water is used as the solvent for the coloring liquid and the acid value of the fiber falls within the range of 0.1mgKOH/g to 50mgKOH/g, as compared with comparative examples 2-1 to 2-5 in which an organic solvent (decalin in comparative example) is used as the solvent for the coloring material and the acid value of the fiber is 0. It is also found that the fibers of examples 2-1 to 2-4 were colored in a dark color and excellent in color fastness and/or solvent resistance because the value of L based on the CIE-la-b color system was 80 or less, the color fastness to rubbing was 3 or more levels in both the dry state and the wet state, and the acid value was 0.1mgKOH/g or more and 50mgKOH/g or less.

(example 3-1)

First, in example 3-1, a coloring liquid was prepared as follows. While stirring c.i. solvent blue 58 as a coloring material and a surfactant of a commercially available product having an HLB value of 11.7 composed of a polyoxyalkylene alkyl ether as a main component, purified water was slowly dropped to obtain an emulsion-like coloring liquid. The formed emulsion-liquefied coloring liquid was adjusted so that the coloring material was 3 mass%, the surfactant was 1.2 mass%, and the purified water was 95.8 mass%.

The state of the coloring liquid prepared as described above was observed to be good. Here, the coloring liquid was observed as follows. The coloring liquid obtained by emulsion or the coloring liquid obtained by dispersion in water was added dropwise to commercially available coarse grass paper in a small amount, and the permeation of the dye liquid was observed. If the coloring liquid spreads uniformly to the rough paper, etc., it is judged to be good. When the coloring material is accumulated on rough paper or the like to form a permeate separated from water, emulsion is not sufficiently performed, and the coloring material is an unstable coloring liquid, and the color development becomes light even when coloring is performed, so that it is not preferable to use the coloring material.

Next, the spinning in example 3-1 will be described.

Next, the prepared coloring liquid (30 ℃) was applied by guided oiling so that the coloring material became 1 mass% based on the mass of the polyethylene fiber and the total amount of the surfactant (the total amount of the surfactant contained in the coloring liquid and the surfactant contained in the oil-top dressing) containing the surfactant whose main component was the polyoxyalkylene alkyl ether was applied in an amount of 0.93 mass%. The temperature of the polyethylene fibrous material at the time of contact with the coloring liquid was 30 ℃ and the tension was 1.2 cN.

Then, the polyethylene fiber material with the coloring liquid adhered thereto was subjected to a heat treatment in a hot air of nitrogen at 110 ℃ for 25 seconds while applying a tension of 3.7cN/dtex, and then to a 4-fold stretching at the same temperature (step 1). Thereafter, the polyethylene fiber material stretched in the 1-step was stretched 4-fold in an oven at 150 ℃ (step 2) and taken up.

The colored polyethylene fiber after the coloring liquid had adhered (after coloring) exhibited good color development, a dry rubbing fastness of grade 4, a wet rubbing fastness of grade 4, and a residual surfactant amount in the fiber was 0.89 mass%. The production conditions used in example 3-1 and the physical properties of the resulting colored polyethylene fiber are shown in Table 5.

(example 3-2)

Colored polyethylene fibers were produced in the same manner as in example 3-1, except that a commercially available surfactant having an HLB value of 7.0, which was composed of polyoxyethylene behenyl ether as a main component of the surfactant contained in the coloring liquid, was used.

Even when a small amount of the coloring liquid of example 3-2 was added dropwise to the coarse grass paper, no aggregates of the coloring material were formed, the dye liquid penetrated uniformly, and the state of the coloring liquid was good. The colored polyethylene fiber of example 3-2 exhibited good color development, a dry crockfastness of grade 4, a wet crockfastness of grade 4, and a residual surfactant amount in the fiber of 0.91% by mass. The production conditions used in example 3-2 and the physical properties of the resulting colored polyethylene fiber are shown in Table 5.

(examples 3 to 3)

Colored polyethylene fibers were produced in the same manner as in example 3-1, except that a commercially available surfactant comprising polyoxyethylene behenyl ether as the main component of the surfactant contained in the coloring liquid was used, and the HLB value of the surfactant was 14.0.

Even when a small amount of the coloring liquid of example 3-3 was added dropwise to the coarse grass paper, no aggregates of the coloring material were formed, the dye liquid penetrated uniformly, and the state of the coloring liquid was good. The colored polyethylene fibers of examples 3 to 3 had good color development, dry crockfastness of grade 4, wet crockfastness of grade 4, and the amount of the surfactant remaining in the fibers was 0.79% by mass. The production conditions used in examples 3 to 3 and the physical properties of the obtained colored polyethylene fiber are shown in Table 5.

(examples 3 to 4)

Colored polyethylene fibers were produced in the same manner as in example 3-1, except that a commercially available surfactant having an HLB value of 10.7, which was composed of polyoxyethylene stearyl ether as a main component of the surfactant contained in the coloring liquid, was used.

Even when a small amount of the coloring liquid of examples 3 to 4 was dropped on the coarse grass paper, there was no aggregation of the coloring material, and the dye liquid penetrated uniformly, and the state of the coloring liquid was good. The colored polyethylene fibers of examples 3 to 4 had good color development, dry crockfastness of grade 4, wet crockfastness of grade 4, and the amount of the surfactant remaining in the fibers was 0.87% by mass. The production conditions used in examples 3 to 4 and the physical properties of the obtained colored polyethylene fiber are shown in Table 5.

(examples 3 to 5)

A coloring liquid was prepared in the same manner as in example 3-1, except that the formed emulsion-liquefied coloring liquid was adjusted so that the coloring material was 3 mass%, the surfactant was 0.6 mass%, and the purified water was 96.4 mass%. Colored polyethylene fibers were produced in the same manner as in example 3-1, except that this coloring liquid was used to attach the polyethylene fibers in such a manner that the total amount of the surfactant was 0.67 mass% based on the mass of the polyethylene fiber material.

Even when a small amount of the coloring liquid of examples 3 to 5 was dropped on the coarse grass paper, there was no aggregation of the coloring material, and the dye liquid penetrated uniformly, and the state of the coloring liquid was good. The colored polyethylene fibers of examples 3 to 5 exhibited good color development, a dry crockfastness of grade 4, a wet crockfastness of grade 3 to 4, and a residual surfactant amount in the fibers of 0.58 mass%. The production conditions used in examples 3 to 5 and the physical properties of the obtained colored polyethylene fibers are shown in Table 5.

(examples 3 to 6)

A coloring liquid was prepared in the same manner as in example 3-1, except that the formed emulsion-liquefied coloring liquid was adjusted so that the coloring material was 3 mass%, the surfactant was 0.24 mass%, and the purified water was 96.76 mass%. Colored polyethylene fibers were produced in the same manner as in example 3-1, except that this coloring liquid was used to attach the polyethylene fibers in such a manner that the total amount of the surfactant was 0.51 mass% based on the mass of the polyethylene fiber material.

The colored polyethylene fibers of examples 3 to 6 exhibited good color development, a dry crockfastness of grade 4, a wet crockfastness of grade 3 to 4, and a residual surfactant amount in the fibers of 0.49 mass%. The production conditions used in examples 3 to 6 and the physical properties of the obtained colored polyethylene fibers are shown in Table 5.

(examples 3 to 7)

A coloring liquid was prepared in the same manner as in example 3-1, except that the formed emulsion-liquefied coloring liquid was adjusted so that the coloring material was 3 mass%, the surfactant was 10 mass%, and the purified water was 87 mass%. Colored polyethylene fibers were produced in the same manner as in the spinning of example 3-1, except that the coloring liquid was used to adhere the polyethylene fibrous material in such a manner that the total amount of the surfactant was 4.6 mass% based on the mass of the polyethylene fibrous material.

The colored polyethylene fibers of examples 3 to 7 exhibited good color development and slightly sticky touch, but had a dry crockfastness of grade 3, a wet crockfastness of grade 3, and a residual surfactant content in the fibers of 4.1 mass%. The production conditions used in examples 3 to 7 and the physical properties of the obtained colored polyethylene fibers are shown in Table 5.

Comparative example 3-1

Colored polyethylene fibers were produced in the same manner as in example 3-1, except that a commercially available surfactant having an HLB value of 6.0, which was composed of polyoxyethylene stearyl ether as a main component of the surfactant contained in the coloring liquid, was used.

When this dye solution of the coloring liquid of comparative example 3-1 was dropped onto the coarse grass paper, the coloring material aggregated and separated from water. The coloring was examined while stirring the coloring liquid, but the colored polyethylene fiber obtained in comparative example 3-1 was pale in color, 3-grade in dry crockfastness, 2-grade in wet crockfastness, and 0.46 mass% in the amount of the surfactant remaining in the fiber. It can be seen that: when aggregation occurs in the coloring liquid, the surfactant has a low HLB value, and thus sufficient emulsion liquefaction cannot be performed, coloring is not performed, and the fastness is also poor. The production conditions used in comparative example 3-1 and the physical properties of the resulting colored polyethylene fiber are shown in Table 6.

Comparative example 3-2

A colored polyethylene fiber was produced in the same manner as in example 3-1, except that a commercially available surfactant having a polyoxyethylene alkyl ether as a main component of the surfactant contained in the coloring liquid was used, and the HLB value was 14.7.

The coloring liquid of comparative example 3-2 was stable in appearance, but when a small amount was added dropwise to the coarse grass paper, the coloring material aggregated and separated from water. The coloring was examined while stirring the coloring liquid, but the colored polyethylene fiber obtained in comparative example 3-2 was pale in color, on the dry crockfastness level 2, on the wet crockfastness level 1-2, and the amount of the surfactant remaining in the fiber was 0.93 mass%. It can be seen that: when the surfactant has high hydrophilicity, it is difficult to blend with a hydrophobic coloring material, and the emulsification is insufficient, which affects the coloring. The production conditions used in comparative example 3-2 and the physical properties of the resulting colored polyethylene fiber are shown in Table 6.

Comparative examples 3 to 3

The emulsion was examined using 0.05 mass% of a commercially available surfactant composed mainly of polyoxyethylene alkyl ether and having an HLB value of 11.7, and the emulsion was evaluated in accordance with example 3-1. However, the coloring liquid prepared was not mixed with water and could not be emulsified, and therefore, coloring was abandoned. The production conditions used in comparative examples 3 to 3 and the physical properties of the resulting colored polyethylene fiber are shown in Table 6.

Comparative examples 3 to 4

A colored polyethylene fiber was produced in the same manner as in example 3-1, except that 12.5 mass% of a commercially available surfactant having an HLB value of 11.7, in which the main component of the surfactant contained in the coloring liquid was a polyoxyethylene alkyl ether, was used, and the coloring liquid was allowed to adhere so that the total amount of the surfactant was 5.7 mass%.

Even when a small amount of the coloring liquid of comparative examples 3 to 4 was dropped on the coarse grass paper, no aggregates of the coloring material were formed, and the state of the coloring liquid obtained in comparative examples 3 to 4 was good. For the colored polyethylene fibers of comparative examples 3 to 4, the dry crockfastness was grade 2 to 3, the wet crockfastness was grade 2, and the amount of the surfactant remaining in the fibers was 5.2% by mass. However, the fibers have a slightly sticky feel and poor wet crockfastness. The production conditions used in comparative examples 3 to 4 and the physical properties of the resulting colored polyethylene fiber are shown in Table 6.

[ Table 5]

[ Table 6]

As is clear from tables 5 and 6, the fibers of examples 3-1 to 3-7 have an L value of 80 or less based on the CIE-la b chromaticity system, a color fastness to rubbing of 3-grade or more in both the dry state and the wet state, and contain 0.4% to 5.0% of a surfactant having an HLB value of 7.0 to 14.0, as compared with the fibers of comparative examples 3-1 to 3-4, and thus are fibers colored in a dark color and excellent in color fastness and/or solvent resistance.

The embodiments and examples described above are all examples and are not limited. The scope of the present invention is defined by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Industrial applicability

According to the present invention, there can be provided: a colored polyethylene fiber which is colored in a dark color and has excellent color fastness and/or solvent resistance. The colored polyethylene fiber has little variation in strength and fineness. Thus, the knitted fabric is suitably used as a material for braids, fishing lines, gloves, ropes, nets, fabrics, knits, and the like.

Claims

1. A colored polyethylene fiber characterized by having a value L of 80 or less based on the CIE-L a b color system and a color fastness to rubbing of 3 or more in both dry and wet states,

the coefficient of variation defined by the following formula 1 of the tensile strength measured at any 10 positions in the longitudinal direction is 10% or less,

the colored polyethylene fibers have a fineness of not more than 10% in the longitudinal direction,

the colored polyethylene fiber has a tensile strength of 18cN/dtex or more and less than 60cN/dtex,

the colored polyethylene fibers comprise a coloring material,

the amount of the coloring material contained in the colored polyethylene fiber is 0.2 to 5 mass%,

the fineness of the monofilament contained in the colored polyethylene fiber is 1dtex to 80dtex,

an elongation at maximum strength of the colored polyethylene fiber is 3.0% to 6.0%,

the colored polyethylene fiber has an initial elastic modulus of 500cN/dtex or more and 2000cN/dtex or less,

a coefficient of variation (%) of tensile strength (standard deviation of tensile strength/average value of tensile strength) × 100 · equation 1,

the method for producing the colored polyethylene fiber comprises the following steps:

and stretching the polyethylene fiber material.

2. A colored polyethylene fiber characterized by having a value L of 80 or less based on the CIE-L a b color system and a color fastness to rubbing of 3 or more in both dry and wet states,

the colored polyethylene fibers comprise a coloring material,

a step of bringing the polyethylene fiber-shaped material into contact with a coloring liquid which contains a coloring material and a polyolefin having a hydrophilic group at one end and has a temperature of 0 ℃ or higher and lower than 60 ℃;

and stretching the polyethylene fiber material.

3. A colored polyethylene fiber characterized by having a value L of 80 or less based on the CIE-L a b color system and a color fastness to rubbing of 3 or more in both dry and wet states,

the colored polyethylene fibers comprise a coloring material,

a step of bringing the polyethylene fiber-shaped material into contact with a coloring liquid which contains a coloring material and a surfactant having an HLB value of 7.0 or more and 14.0 or less and has a temperature of 0 ℃ or more and less than 60 ℃;

and stretching the polyethylene fiber material.

4. A colored polyethylene fiber characterized by having a value L of 80 or less based on the CIE-L a b color system and a color fastness to rubbing of 3 or more in both dry and wet states,

the colored polyethylene fibers comprise a coloring material,

the colored polyethylene fiber has an acid value of 0.1mgKOH/g or more and 50mgKOH/g or less,

the coefficient of variation (%) of tensile strength (standard deviation of tensile strength/average value of tensile strength) × 100 · equation 1.

5. A colored polyethylene fiber characterized by having a value L of 80 or less based on the CIE-L a b color system and a color fastness to rubbing of 3 or more in both dry and wet states,

the colored polyethylene fibers comprise a coloring material,

the colored polyethylene fiber contains 0.4-5.0% of surfactant with HLB value of 7.0-14.0,

6. A colored polyethylene fiber characterized by having a solvent resistance of 75% or more as determined by the following measurement method,

the colored polyethylene fibers comprise a coloring material,

a step of stretching the polyethylene fiber-like material,

the solvent resistance was measured by the following method:

the colored polyethylene fiber to become 0.1g/mL acetone and at room temperature and standing for 24 hours, colored polyethylene fiber impregnated using acetone, and the colored polyethylene fiber impregnated and 20 + -5 degrees C after standing for 24 hours acetone, using ultraviolet visible spectrophotometer measurement wavelength 350nm to 780nm range of transmittance, from the transmittance curve obtained in the transmittance value of the integral value of the transmittance, through the following equation 2 calculation of solvent resistance,

solvent resistance (%) - (T)₁/T₀) X 100. formula 2

7. A colored polyethylene fiber characterized by having a solvent resistance of 75% or more as determined by the following measurement method,

the colored polyethylene fibers comprise a coloring material,

a step of stretching the polyethylene fiber-like material,

the solvent resistance was measured by the following method:

solvent resistance (%) - (T)₁/T₀) X 100. formula 2

8. A colored polyethylene fiber characterized by having a solvent resistance of 75% or more as determined by the following measurement method,

the colored polyethylene fibers comprise a coloring material,

a step of stretching the polyethylene fiber-like material,

the solvent resistance was measured by the following method:

solvent resistance (%) - (T)₁/T₀) X 100. formula 2

9. A colored polyethylene fiber characterized by having a solvent resistance of 75% or more as determined by the following measurement method,

the colored polyethylene fibers comprise a coloring material,

the solvent resistance was measured by the following method:

solvent resistance (%) - (T)₁/T₀) X 100. formula 2

10. A colored polyethylene fiber characterized by having a solvent resistance of 75% or more as determined by the following measurement method,

the colored polyethylene fibers comprise a coloring material,

the solvent resistance was measured by the following method:

solvent resistance (%) - (T)₁/T₀) X 100. formula 2

In the formula 2, T₀T represents the integral value of the transmittance of acetone at a wavelength of 350nm to 780nm₁Showing the transmittance of acetone after impregnation of a colored polyethylene fiber having a wavelength of 350 to 780nmThe integral value.

11. Coloured polyethylene fibres according to any one of claims 1 to 10, characterised in that they comprise a colouring material which is an oil-soluble dye.

12. A braid comprising at least 1 colored polyethylene fiber according to any one of claims 1 to 11.

13. The braid of claim 12, wherein the strength of the fibers unwound from the braid is 15cN/dtex or more.

14. A fishing line comprising the colored polyethylene fiber of any one of claims 1 to 11.

15. A glove comprising the colored polyethylene fiber of any one of claims 1-11.

16. A rope comprising the pigmented polyethylene fiber of any one of claims 1-11.

17. A web comprising the pigmented polyethylene fiber of any one of claims 1-11.

18. A fabric or knit comprising the colored polyethylene fiber of any one of claims 1 to 11.

19. The colored polyethylene fiber according to any one of claims 1 to 3 and 6 to 8, wherein the temperature of the polyethylene fiber material in contact with the coloring liquid is 50 ℃ or lower.

20. The colored polyethylene fiber according to any one of claims 1 to 3 and 6 to 8, wherein the heating is performed while applying a tension of 0.8 to 6.5cN/dtex to the polyethylene fibrous material to which the coloring liquid is applied.

21. The colored polyethylene fiber according to any one of claims 1 to 3 and 6 to 8, wherein the method for producing the colored polyethylene fiber comprises the steps of: the polyethylene fiber-like material to which the coloring liquid has been applied is stretched at a stretch ratio of 2 times or more.