Highly functional polyethylene fiber, and product using same

Abstract

The present invention addresses the problem of providing a highly functional polyethylene fiber having a lower environmental load compared with those of highly functional polyethylene fibers using conventional fossil fuel-derived polyethylene resins. The present invention is a highly functional polyethylene fiber characterized by containing a polyethylene resin having a biomass degree of 95% or more as calculated by the measurement of radiocarbon (C14) using an accelerator mass spectrometer (AMS).

Description

High-performance polyethylene fiber and products using it

[0001] The present invention relates to a high-performance polyethylene fiber obtained from a biomass-derived raw material, a product containing the polyethylene fiber, and a method for producing the polyethylene fiber.

[0002] Polyethylene fibers are used in a variety of products, including braids, woven fabrics, knitted fabrics, nonwoven fabrics, bags, and vests, as well as in medical applications such as medical sutures and artificial ligaments. As the uses of polyethylene fibers become more diverse, polyethylene fibers with functionality suited to the required characteristics of these products are in demand. For example, ultra-high molecular weight polyethylene fibers with high strength and high elastic modulus are used for braided multifilament or monofilament braids used in many applications, such as fishing lines, nets, and ropes. Furthermore, high-strength polyethylene fibers with excellent cut resistance are used in fields requiring cut resistance, such as gloves and vests (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2004-019050

[0004] Conventional high-performance polyethylene fibers use polyethylene resins produced from raw materials derived from fossil fuels, which is undesirable from the viewpoint of reducing the environmental load. An object of the present invention is to provide a high-performance polyethylene fiber that imposes a lower environmental load than conventional high-performance polyethylene fibers using polyethylene resins derived from fossil fuels.

[0005] The high-performance polyethylene fiber of the present invention has the following configuration: [1] Radiocarbon (C) analysis using an accelerator mass spectrometer (AMS) １４) measurement. [2] A high-performance polyethylene fiber comprising a polyethylene resin having a biomass degree of 95% or more calculated by the biomass ratio (biomass ratio) measurement. [2] The high-performance polyethylene fiber according to [1], which has a single filament fineness of 0.5 to 10 dtex. [3] The high-performance polyethylene fiber according to [1] or [2], which has a tensile strength of 6 cN / dtex or more and an initial modulus of elasticity of 150 cN / dtex or more. [4] The high-performance polyethylene fiber according to any one of [1] to [3], which has a crystallinity of 60% or more. [5] The high-performance polyethylene fiber according to any one of [1] to [4], which has a polystyrene-equivalent weight-average molecular weight of 70,000 to 1,000,000. [6] The high-performance polyethylene fiber according to any one of [1] to [5], wherein the polyethylene resin contains at least one alkyl side chain selected from the group consisting of methyl, ethyl, and butyl groups, and has 0.3 or more alkyl side chains per 1,000 carbon atoms. [7] The high-performance polyethylene fiber according to any one of [1] to [6], which has a coupe tester index value of 4.0 or more as measured in accordance with European Standard EN 388. [8] The cool-to-the-touch value as measured in accordance with JIS L1927 is 0.2 W / cm ２ [9] The high-performance polyethylene fiber according to any one of [1] to [8], which has a thermal conductivity of 0.05 to 0.40 W / (m K) as measured by bringing the polyethylene fiber at 20°C into contact with a heat source plate at 30.0°C.

[10] A product comprising the high-performance polyethylene fiber according to any one of [1] to [9].

[11] A product containing radiocarbon (C) using an accelerator mass spectrometer (AMS). １４ a step of melt-extruding a resin composition containing a polyethylene resin having a biomass degree of 95% or more as calculated by a biomass ratio measurement (BRI) at a temperature 10°C or more higher than the melting point of the resin composition; a step of supplying the melt-extruded resin composition to a spinning nozzle at a temperature 80°C or more higher than the melting point of the resin composition; a step of cooling the fibrous material obtained by extruding the fibrous material from the spinning nozzle and then winding it at a speed of 25 m / min or more; and a step of drawing the fibrous material at a temperature equal to or lower than the melting point of the fibrous material at least once to a draw ratio of 5 times or more.

[0006] According to the present invention, a high-performance polyethylene fiber can be provided which has a lower environmental impact than polyethylene fibers made from polyethylene resins derived from fossil fuels. The high-performance polyethylene fiber of the present invention is particularly suitable for various products.

[0007] The high-performance polyethylene fiber of the present invention was analyzed by radiocarbon (C) using an accelerator mass spectrometer (AMS). １４ The high-performance polyethylene fiber of the present invention is a resin composition containing a polyethylene resin having a biomass content of 95% or more as calculated by a biomass content measurement (biomass content measurement). Because the high-performance polyethylene fiber of the present invention uses a biomass-derived polyethylene resin made from renewable biological resources such as plants, it has a lower environmental impact than polyethylene fibers made from polyethylene resins derived from fossil fuels.

[0008] In the present invention, biomass refers to renewable, biologically derived organic resources, excluding fossil resources. Specific examples of biomass include livestock resources such as livestock excrement, food resources such as processing residues, food waste, and animal and plant residues, industrial resources such as pulp waste liquor, sawmill residues, and construction waste wood, and waste biomass such as sewage sludge; unused biomass such as forestry resources such as forest residues, agricultural resources such as rice straw, rice husks, and wheat straw, and marine resources such as shells and seaweed; and resource crops such as carbohydrate resources such as sugarcane and sugar beet, starch resources such as rice, potatoes, and corn, oil resources such as rapeseed, soybeans, peanuts, oil palm, and castor bean, and herbaceous resources such as Erianthus.

[0009] (1) Biomass Degree In the present invention, a polyethylene resin having a biomass degree of 95% or more is used. A polyethylene resin having a biomass degree of 95% or more refers to a polyethylene resin in which 95% or more of the raw material is derived from biomass. The biomass degree of the polyethylene resin is preferably 97% or more, more preferably 98% or more, even more preferably 99% or more, and even more preferably 100%. The remainder (5% or less) of the polyethylene resin may contain inorganic metals such as lithium, calcium, magnesium, aluminum, barium, silicon, cobalt, chromium, zinc, iron, copper, zirconium, magnesium, antimony, hafnium, manganese, sodium, nickel, phosphorus, and titanium as a fossil fuel-derived polyolefin resin or catalyst residue. However, the higher the biomass degree, the less environmental impact. The biomass-derived raw material may be obtained by any known production method, and the type of biomass raw material and the production method are not limited. For example, polyethylene resins produced from biomass-derived raw materials can be used, such as polyethylene resins obtained by dehydrating ethanol (biomass ethanol) obtained by fermenting biomass raw materials and polymerizing the resulting ethylene, or polyethylene resins obtained by chemically treating biomass raw materials. The biomass content is the content of biomass-derived carbon relative to the total carbon in the polyethylene raw material, and is measured by radiocarbon (C) analysis using an accelerator mass spectrometer (AMS) in accordance with ASTM D6866-06. １４ For example, in the present invention, the biomass degree of a polyethylene raw material can be measured and used as the biomass degree of the polyethylene resin.

[0010] The high-performance polyethylene fiber of the present invention is composed of a resin composition containing a polyethylene resin having a biomass content of 95% or more, and the resin composition may contain a resin other than the polyethylene resin having a biomass content of 95% or more (hereinafter referred to as "other resin"). Examples of other resins include low-density polyethylene resin and polypropylene resin, and one or more of the other resins may be contained.

[0011] The content of the polyethylene resin having a biomass degree of 95% or more in the resin composition (100% by mass) is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, still more preferably 99% by mass or more, and most preferably 100% by mass. The higher the content of the polyethylene resin having a biomass degree of 95% or more in the resin composition, the greater the effect of reducing the environmental load, which is desirable.

[0012] In the present invention, the high-performance polyethylene fiber preferably satisfies one of (7) index value, (8) cool touch, and (9) thermal conductivity, and more preferably satisfies all of these. In addition to these, the high-performance polyethylene fiber preferably satisfies one or more of (2) to (6), and more preferably satisfies all of (2) to (6). In the present invention, the polyethylene fiber having excellent mechanical properties particularly satisfies (3) tensile strength and initial modulus of elasticity.

[0013] (2) Single Yarn Fineness The average single yarn fineness of the high-performance polyethylene fiber of the present invention is preferably 0.5 dtex or more, more preferably 0.6 dtex or more, even more preferably 1.0 dtex or more, and is preferably 10 dtex or less, more preferably 5 dtex or less. An average single yarn fineness of 0.5 dtex or more can impart sufficient strength to the high-performance polyethylene fiber of the present invention. In addition, woven or knitted fabrics (woven or knitted fabrics) using the high-performance polyethylene fiber in the above range are desirable because they do not have a stiff feel and do not lose their flexibility.

[0014] (3) Tensile Strength and Initial Modulus of Elasticity The high-performance polyethylene fiber of the present invention preferably has a tensile strength of 6 cN / dtex or more and an initial modulus of elasticity of 150 cN / dtex or more. Increasing the tensile strength and initial modulus of elasticity can improve the mechanical properties of the product. The tensile strength is more preferably 8 cN / dtex or more, even more preferably 9 cN / dtex or more, and even more preferably 10 cN / dtex or more. The higher the tensile strength, the more sufficient strength can be imparted. There is no upper limit, but it is preferably 30 cN / dtex or less, more preferably 20 cN / dtex or less. The initial modulus of elasticity is more preferably 200 cN / dtex or more, and even more preferably 250 cN / dtex or more. The higher the initial modulus of elasticity, the more suppressed changes in physical properties and shape due to external force can be. There is no upper limit, but it is preferably 600 cN / dtex or less, more preferably 500 cN / dtex or less.

[0015] (4) Crystallinity The high-performance polyethylene fiber of the present invention has a crystallinity of preferably 60% or more, more preferably 65% ​​or more, and even more preferably 70% or more. Increasing the crystallinity of the polyethylene fiber can suppress changes in the fiber properties and also improve the mechanical properties of applied products.

[0016] (5) Weight-Average Molecular Weight The weight-average molecular weight of the high-performance polyethylene fiber of the present invention is preferably 70,000 or more, more preferably 100,000 or more, even more preferably 200,000 or more, and even more preferably 300,000 or more, and is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 350,000 or less. If the weight-average molecular weight is too low, defects due to molecular chain ends increase, resulting in reduced stretchability, reduced productivity, and insufficient strength. If the weight-average molecular weight is too high, for example, the melt viscosity during spinning becomes very high, making it difficult to extrude from a nozzle, which is undesirable. The molecular weight distribution (Mw / Mn) of the high-performance polyethylene fiber of the present invention is not particularly limited, but is preferably 3.0 or more, more preferably 5.0 or more, and preferably 10.0 or less, more preferably 8.0 or less.

[0017] (6) Number of Alkyl Branches (Number / 1,000 Carbon Atoms) The polyethylene resin of the present invention having a biomass content of 95% or more preferably has 0.3 or more, more preferably 0.5 or more, and even more preferably 1.0 or more alkyl side chains per 1,000 carbon atoms, and preferably 10.0 or less, more preferably 8.0 or less, and even more preferably 5.0 or less. The alkyl side chain is at least one selected from the group consisting of methyl, ethyl, and butyl groups. The more alkyl side chains there are, the better the creep properties and dimensional stability. On the other hand, if there are too many alkyl side chains, stretchability may be impaired.

[0018] (7) Index Value The index value of the high-performance polyethylene fiber of the present invention measured by a coupe tester is preferably 4.0 or more, more preferably 4.5 or more, and even more preferably 5.0 or more. A higher index value improves cut resistance, making the fiber suitable for protective woven and knitted fabrics, etc. The coupe tester index value is a value measured based on European Standard (EN388 method).

[0019] (8) Coolness to the Touch (Q-max) The coolness to the touch of the high-performance polyethylene fiber of the present invention is preferably 0.2 W / cm ２ More preferably, 0.25 W / cm ２ More preferably, 0.3 W / cm ２ More preferably, 0.35 W / cm ２ or more, preferably 1.0 W / cm ２ or less, more preferably 0.8 W / cm ２ or less, more preferably 0.6 W / cm ２ The higher the coolness to the touch, the more the coolness of the skin in contact with the polyethylene fiber can be improved. There is no particular upper limit. The coolness to the touch is a property that indicates the coolness to the touch of a fabric, and is defined as the maximum value of the initial heat flux (Q-max: W / cm) when the fabric comes into contact with the skin, measured according to JIS L1927. ２ )

[0020] (9) Thermal Conductivity The thermal conductivity of the high-performance polyethylene fiber of the present invention is preferably 0.05 W / (m K) or more, more preferably 0.10 W / (m K) or more, even more preferably 0.15 W / (m K) or more, and even more preferably 0.20 W / (m K) or more, and is preferably 0.40 W / (m K) or less, more preferably 0.35 W / (m K) or less, and even more preferably 0.30 W / (m K) or less. Higher thermal conductivity is preferred because it makes it easier to achieve a cool feeling to the touch. The thermal conductivity is a value measured by contacting a 20°C test specimen with a heat source plate at 30.0°C (temperature difference ΔT = 10°C from the test specimen).

[0021] Other Additives The high-performance polyethylene fiber of the present invention may contain one or more additives, such as oils, crosslinking agents, plasticizers, lubricants, antioxidants, UV absorbers, light stabilizers, reinforcing agents, hard particles, antistatic agents, pigments, dyes, and modifying resins.

[0022] Fiber Structure The structure of the high-performance polyethylene fiber of the present invention is not limited, and may be, for example, a composite fiber such as a core-sheath structure in which the high-performance polyethylene fiber of the present invention is combined with other fibers. When the high-performance polyethylene fiber of the present invention has a core-sheath structure, the high-performance polyethylene fiber of the present invention may be either a core or a sheath structure. The other fiber is not particularly limited, but is preferably a fiber with a biomass degree of 95% or more, more preferably a polyethylene fiber containing a polyethylene resin with a biomass degree of 95% or more and with different blending amounts of additives and other resins. The cross section of the high-performance polyethylene fiber is not limited, and may have any shape, such as a circle, a star, a triangle, or a hollow.

[0023] Products The high-performance polyethylene fiber of the present invention can be used in various products. In such cases, it is desirable to appropriately adjust the above-mentioned physical properties depending on the required characteristics of the product. Examples of products using the high-performance polyethylene fiber of the present invention include, but are not limited to, woven fabrics, knitted fabrics, nonwoven fabrics, bags, braided cords, nets, gloves, fishing lines, ropes, medical sutures, artificial ligaments, vests, etc. Furthermore, it is sufficient that at least a part of the product contains the high-performance polyethylene fiber of the present invention, and the proportion of the high-performance polyethylene fiber in the product is not limited.

[0024] The high-performance polyethylene fiber of the present invention is suitable for products requiring cut resistance, such as cut-resistant woven and knitted fabrics, gloves, and vests. Gloves can be produced, for example, by knitting the polyethylene fiber of the present invention using a knitting machine, or by weaving the polyethylene fiber of the present invention into a fabric, which can then be cut and sewn into gloves. The gloves can be used as is, or, if necessary, can be coated with a urethane-based or ethylene-based resin (anti-slip material) to provide anti-slip properties.

[0025] In particular, since the polyethylene fiber of the present invention has excellent cut resistance, it can be suitably used not only for the above-mentioned gloves but also for fiber-reinforced resin reinforcements, cement reinforcements, fiber-reinforced rubber reinforcements, or protective materials that are expected to be subject to environmental changes, bulletproof materials, medical sutures, artificial tendons, artificial muscles, machine tool parts, battery separators, chemical filters, etc. Of course, products using the polyethylene fiber of the present invention are not limited to these.

[0026] The high-performance polyethylene fiber of the present invention has high strength and excellent moldability. Therefore, it can be processed into woven fabrics, knitted fabrics, nonwoven fabrics, braided cords, nets, etc. Specific applications include not only the gloves and vests mentioned above, but also fishing lines and ropes. Furthermore, it is suitable for use in tapes, material protective covers, sheets, kite lines, bags, interior materials, backpacks, footwear, sportswear, outdoor wear, tactical wear, workwear, performance apparel, bowstrings, sailcloth, tents, tent materials, medical sutures, and artificial ligaments.

[0027] The method for producing the high-performance polyethylene fiber of the present invention will be described below. The method will be described based on melt spinning, which is a preferred method for producing the high-performance polyethylene fiber of the present invention, but the production method of the present invention is not limited to this.

[0028] Melt-extrusion step: A resin composition containing a polyethylene resin having a biomass content of 95% or more is melted in an extruder or the like and melt-extruded at a temperature 10°C or higher, preferably 50°C or higher, and more preferably 80°C or higher than the melting point of the resin composition. During melt-extrusion, it is preferable to supply an inert gas such as nitrogen to the extruder. The pressure of the inert gas supplied is not limited, but is preferably 0.001 MPa or higher, more preferably 0.05 MPa or higher, and even more preferably 0.1 MPa or higher, and is preferably 0.8 MPa or lower, more preferably 0.7 MPa or lower, and even more preferably 0.5 MPa or lower.

[0029] Spinning Step The melt-extruded resin composition is supplied to a spinning nozzle using a constant-rate supply device or the like at a temperature 80° C. or higher, preferably 100° C. or higher, than the melting point of the resin composition. The diameter of the spinning nozzle is not limited, but is preferably 0.3 mm or higher, more preferably 0.5 mm or higher, and is preferably 2.5 mm or lower, more preferably 1.5 mm or lower.

[0030] The single-hole discharge rate of the molten resin composition extruded from the spinning nozzle is not limited, but is preferably 0.1 g / min or more, more preferably 0.2 g / min or more, and is preferably 5 g / min or less, more preferably 3 g / min or less, and even more preferably 1 g / min or less.

[0031] Winding Step The fibrous material discharged from the spinning nozzle is preferably passed through a heat-retaining section and then cooled by any cooling means such as quenching. The cooling temperature is preferably 40°C or lower, more preferably 35°C or lower, and even more preferably 30°C or lower, and is preferably 5°C or higher, more preferably 10°C or higher, and even more preferably 15°C or higher. The cooling rate is not limited, but is preferably 0.1 m / s or higher, more preferably 0.5 m / s or higher, and preferably 5.0 m / s or lower, more preferably 3.0 m / s or lower, and even more preferably 1.0 m / s or lower.

[0032] After cooling, the fibrous material is wound up at a constant speed. The winding speed is not limited, but is preferably 25 m / min or more, more preferably 50 m / min or more, even more preferably 100 m / min or more, and even more preferably 200 m / min or more, and is preferably 500 m / min or less, more preferably 400 m / min or less, and even more preferably 300 m / min or less.

[0033] Stretching step: Next, the wound fibrous material is stretched using a temperature-controllable roller or the like. The number of stretching times is preferably one or more, more preferably two or more. The stretching ratio (total when stretching multiple times) is preferably 5 times or more, more preferably 6 times or more, even more preferably 7 times or more, and preferably 30 times or less, more preferably 25 times or less, and even more preferably 20 times or less. When stretching multiple times, for example, stretching twice, the stretching ratio in the first stage is preferably 1.05 times or more, more preferably 2.0 times or more, and preferably 4.0 times or less, more preferably 3.0 times or less. The stretching ratio in the second stage is preferably 2.5 times or more, more preferably 5.0 times or more, and preferably 15 times or less, more preferably 10 times or less.

[0034] The stretching temperature is preferably a temperature not higher than the melting point of the resin composition constituting the fibrous material. When stretching is performed multiple times, the roller temperature in the first stage (initial stretching temperature) is preferably lower than the crystal dispersion temperature of the fiber, and the stretching temperature is preferably set to 80°C or lower, more preferably 70°C or lower. The stretching temperature in the second stage is preferably higher than the crystal dispersion temperature of the fiber, and the stretching temperature is preferably 90°C or higher. The stretching temperature is preferably lower than the melting point of the fiber, more preferably lower than the melting point of the fiber.

[0035] This application claims the benefit of priority based on Japanese Patent Application No. 2023-188337, filed on November 2, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-188337, filed on November 2, 2023, are incorporated herein by reference.

[0036] The present invention will be explained in more detail below with reference to examples. However, the present invention is not limited to the following examples, and it is possible to carry out the invention by making appropriate modifications within the scope of the above and below-described aims, and all such modifications are included in the technical scope of the present invention.

[0037] The measurement conditions for each sample are as follows.

[0038] (1) Biomass Degree Carbon-14 counting, carbon-13 concentration (carbon-13 / carbon-12), and carbon-14 concentration (carbon-14 / carbon-12) were measured in accordance with ASTM D6866-21. For the measurements, oxalic acid (HOxII) provided by the National Institute of Standards (NIST) was used as the standard sample. Measurements of this standard sample and a background sample were also performed simultaneously. Carbon-14 concentration (pMC) refers to the ratio of the carbon-14 concentration of the sample carbon to the standard modern carbon. In accordance with ASTM D6866-21, the carbon-14 concentration (pMC) measured as described above was rounded to two decimal places to determine the biomass-derived carbon concentration. In accordance with ASTM D6866-21, the biomass ratio was calculated using pMC corrected by δC (the carbon-13 concentration (carbon-13 / carbon-12) of the sample carbon was measured, and the deviation from the reference sample was expressed in thousandths (0 / 00)). The biomass ratio (%) was rounded to the nearest integer. The atmospheric correction factor used was the value for 2019-2021 listed in ASTM D6866-21 (latest edition) (100.0 pMC). Note that the carbon-14 concentration in the atmosphere may continue to decrease (change) year by year. If the atmospheric correction factor value listed in ASTM D6866 (latest edition) is changed from 100.0 pMC in the future, the atmospheric correction factor will be the value listed in ASTM D6866 for the year in which the raw material related to this invention was produced. If the production year of the raw material is unknown, the atmospheric correction factor was set to 100.0 pMC. Biomass (%) = (pMC of sample corrected by δC / atmospheric correction factor) × 100 (1)

[0039] (2) Single Yarn Fineness The sample was cut into 100 cm pieces at three different positions in the longitudinal direction, and the weights were measured. The average value was used to determine the yarn fineness. The single yarn fineness (dtex) was calculated from the yarn fineness.

[0040] (3) Tensile strength and initial modulus of elasticity Using a "Tensilon" manufactured by Orientec Co., Ltd., a strain-stress curve was measured under conditions of an atmospheric temperature of 20°C and a relative humidity of 65% under conditions of a sample length of 200 mm (length between chucks) and an elongation rate of 100% / min, and the stress at the breaking point was used to calculate the tensile strength (cN / dtex), and the initial modulus of elasticity (cN / dtex) was calculated from the tangent giving the maximum gradient near the origin of the curve. Each value was the average of seven measurements.

[0041] (4) Crystallinity Data was measured using a differential scanning calorimeter (manufactured by TA Instruments, "DSC Measurement Apparatus"), and the measured data was analyzed using TRIOS Software (manufactured by TA Instruments). The sample was cut into pieces of 5 mg or less, and approximately 2 mg was packed and sealed in an aluminum pan. A similar empty aluminum pan was used as a reference. Measurements were performed under inert gas in a temperature range of 30°C to 200°C, with a heating rate of approximately 10°C / min. The baseline of the obtained temperature-rising DSC curve was corrected, and the measured heat of fusion was calculated by dividing the peak area by the sample mass, and the crystallinity was determined using the following formula: Crystallinity (%) = 100 x (measured heat of fusion (J / g)) / (287 (J / g)).

[0042] (5) Weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the sample in terms of polystyrene were measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw / Mn) was calculated. The GPC apparatus used was a Waters GPC 150C ALC / GPC, and the columns used were one GPC UT802.5 and two UT806M columns manufactured by SHODEX. o-Dichlorobenzene was used as the measurement solvent, and the column temperature was set to 145°C. The sample concentration was 1.0 mg / ml, and 200 microliters were injected and measured. A molecular weight calibration curve was prepared using a polystyrene sample with a known molecular weight by the universal calibration method.

[0043] (6) Number of alkyl branches (number of alkyl side chains per 1,000 carbon atoms) 250 mg of a sample was dissolved in o-dichlorobenzene + p-dichlorobenzene-d4 (7 + 3 vol) at 145°C, and C-NMR was measured at 120°C. The number was estimated from the obtained C-NMR spectrum based on the following: When the ethylene chain peak of polyethylene is taken as 30 ppm, the peak derived from methyl side chains is detected at around 37.5 ppm, the peak derived from ethyl side chains is detected at around 34 ppm, and the peak derived from butyl side chains is detected at around 23.5 ppm. When the integral value of the ethylene chain peak is taken as 1000, the peak integral value at 37.5 ppm is taken as A, the peak integral value at 34 ppm is taken as B, and the peak integral value at 23.5 ppm is taken as C, the number of methyl side chains was calculated to be A / 2 (number / 1000 C), the number of ethyl side chains was calculated to be B / 2 (number / 1000 C), and the number of butyl side chains was calculated to be C / 2 (number / 1000 C).

[0044] (7) Index Value of Coupe Tester (Cut Resistance) Measurement was carried out using a Coupe Tester (manufactured by SODMAT) based on the European standard EN388. Specifically, an aluminum foil was placed on the sample stage of the device, and a sample (polyethylene fiber) with a basis weight of about 350 g / m was placed on the aluminum foil. ２ A knitted fabric sample (6 cm x 10 cm) was placed on the test piece. The circular blade attached to the test piece was then rotated in the opposite direction to the running direction and run over the cotton cloth. After the cotton cloth was cut, the circular blade came into contact with the aluminum foil, detecting electrical conduction and stopping the rotation of the circular blade to terminate the test. While the circular blade was operating, the counter in the test piece counted the number of times the circular blade reciprocated, and the count value was recorded.

[0045] In this test, the basis weight is approximately 300 g / m ２ A cotton cloth (cotton) was used as a blank, and the cut resistance of the knitted fabric samples was evaluated. The test started with the blank, and the blank test and the knitted fabric sample test were alternately performed. The knitted fabric sample was tested five times, and finally, the blank test was performed a sixth time to form one set of tests. Five sets of this test were performed, and the average index value of the five sets was used to evaluate the cut resistance. A higher index value means better cut resistance.

[0046] The index value was calculated using the following formulas: A = (count value of knitted sample (or blank cotton fabric) before test + count value of knitted sample (or blank cotton fabric) after test) / 2 Index value = (count value of knitted sample (or blank cotton fabric) + A) / A The cutter used to evaluate cut resistance was a φ45 mm L-type rotary cutter manufactured by OLFA Corporation. The material was SKS-7 tungsten steel, and the blade thickness was 0.3 mm. The load applied during the test was 3.14 N (320 gf), and the evaluation was performed.

[0047] (8) Coolness to the touch (Q-max) was measured using a KES-F7 (Thermo Labo II) device based on JIS L1927. The room temperature around the measurement device and the measurement table of the measurement device were set to 20±2°C and 65±4% RH. Heat was supplied by contacting a heat supply device with the heat source plate, and the heat source plate was set to 30.0°C (temperature difference ΔT = 10°C with the knitted sample). A 15cm x 15cm knitted sample (sample = made from polyethylene fiber) adjusted to 20±2°C was placed on the measurement table. The heat source plate and the heat supply device were separated to stop the heat supply, and the measurement section was quickly brought into contact with the knitted sample at a pressure of 1.02 kPa while maintaining the measurement section horizontal. The temperature of the heat source plate at the beginning of contact was measured over time for approximately 5 seconds. From the measurement results, the heat flux q(t) was calculated using the following formulas (1) and (2), and the maximum value q(t) (= Q-max) within the measurement time was determined. The average value of five measured values ​​was used for each value. Formula (1): T(t) = Tp0 - Tp(t) Formula (2): q(t) = M × C / A × dT(t) / dt Where, q(t): heat flux (W / cm ２ ), A: area of ​​heat source plate (cm ２ ), M: mass of the heat source plate (kg), C: specific heat of the heat source plate [J / (kg·K)], Tp0: initial temperature of the heat source plate (°C), Tp(t): temperature of the heat source plate after t seconds of contact (°C), T(t): temperature drop of the heat source plate (°C).

[0048] (9) Thermal Conductivity Measurements were performed using a KES-F7 (Thermo Labo II) device. The room temperature around the measurement device and the measurement table of the measurement device were set to 20±2°C and 65±4% RH. Heat was supplied by contacting a heat supply device with the heat source plate, which was set to 30.0°C (temperature difference with the knitted sample, ΔT = 10°C). A 15cm x 15cm knitted sample (sample made from polyethylene fiber) adjusted to 20±2°C was placed on the measurement table, and the heat source plate was placed on top of it. The power consumption of the heat plate after 10 minutes was measured. From the measurement results, the thermal conductivity was calculated using the following formula (3). Note that each value was the average of five measurements. Formula (3): K = (W x D) / (A x ΔT) where K: thermal conductivity (W / m K), D: thickness of the fabric sample (m), A: contact area of ​​the heat source plate (= 0.0025 m ２ ), ΔT: temperature difference between both sides of the fabric sample (=10°C), W: heat flow loss (watts).

[0049] Example 1: Using biomass-derived raw materials, high-density polyethylene having a weight-average molecular weight of 331,000 and a weight-average molecular weight to number-average molecular weight ratio of 6.2 was extruded from a 0.9 mm diameter, 180H spinneret at 280°C with a single-hole throughput rate of 0.30 g / min. The extruded filament was passed through a 7 cm warming zone, then quenched at 20°C at 0.5 m / s and wound up at a speed of 290 m / min to obtain a polyethylene fibrous material (undrawn yarn). The polyethylene fibrous material was drawn using multiple temperature-controllable rollers. A first-stage drawing was performed at 55°C to a draw ratio of 2.5 times, followed by further heating and drawing to 100°C to produce a polyethylene fiber (drawn yarn) with a total draw ratio of 10.0 times in the drawing process. The physical properties of the obtained polyethylene fiber are shown in Table 1.

[0050] Comparative Example 1 A high-performance polyethylene fiber (drawn yarn) was produced under the same conditions as in Example 1, except that a fossil fuel-derived raw material was used, and high-density polyethylene having a weight-average molecular weight of 325,000 and a ratio of weight-average molecular weight to number-average molecular weight of 2.8 was used. The physical properties of the obtained polyethylene fiber are shown in Table 1.

[0051]

[0052] Example 1 is an example of the present invention and is a high-performance polyethylene fiber containing polyethylene resin with a biomass content of 98%. Comparative Example 1 is a polyethylene fiber composed of polyethylene resin with a biomass content of 0% because it uses raw materials derived from fossil fuels. Therefore, Example 1 has a greater environmental impact reduction effect than Comparative Example 1. Example 1 also had sufficient mechanical properties in terms of both tensile strength and initial modulus of elasticity. Furthermore, the product using the polyethylene fiber of Example 1 had sufficient cut resistance (index value), cool touch (Q-max), and thermal conductivity compared to the Comparative Example, which used raw materials derived from fossil fuels.

[0053] The high-performance polyethylene fiber of the present invention has a small environmental impact. Furthermore, the high-performance polyethylene fiber of the present invention has particularly excellent cut resistance properties. Therefore, cord-like products, woven or knitted fabrics, gloves, and ropes made from the high-performance polyethylene fiber of the present invention have particularly excellent cut resistance and exhibit excellent performance, for example, as butcher's strings, safety gloves, safety ropes, and finishing ropes. Furthermore, the high-performance polyethylene fiber of the present invention is not limited to the above-mentioned molded products, and can be widely used in industrial materials, packaging materials, and the like, as highly shrinkable fabrics and tapes. It also exhibits excellent performance when used as a medical fiber for medical sutures, artificial tendons, artificial muscles, and the like.

Claims

1. Radiocarbon (C) using Accelerator Mass Spectrometer (AMS) １４ ) A high-performance polyethylene fiber comprising a polyethylene resin having a biomass degree of 95% or more calculated by measurement.

2. The high-performance polyethylene fiber according to claim 1, wherein the single fiber fineness is 0.5 to 10 dtex.

3. The high-performance polyethylene fiber according to claim 1, which has a tensile strength of 6 cN / dtex or more and an initial modulus of elasticity of 150 cN / dtex or more.

4. The high-performance polyethylene fiber according to claim 1, having a crystallinity of 60% or more.

5. The high-performance polyethylene fiber according to claim 1, wherein the polyethylene fiber has a weight average molecular weight in terms of polystyrene of 70,000 to 1,000,000.

6. The high-performance polyethylene fiber according to claim 1, wherein the polyethylene resin contains at least one alkyl side chain selected from the group consisting of methyl groups, ethyl groups, and butyl groups, and has 0.3 or more alkyl side chains per 1,000 carbon atoms.

7. High-performance polyethylene fiber according to claim 1, which has a Coupe Tester index value of 4.0 or more as measured based on the European Standard EN388 method.

8. The cooling sensation measured based on JIS L1927 is 0.2 W / cm ２ The high-performance polyethylene fiber according to claim 1.

9. High-performance polyethylene fiber according to claim 1, which has a thermal conductivity of 0.05 to 0.40 W / (m·K) as measured by contacting the polyethylene fiber at 20° C. with a heat source plate at 30.0° C.

10. A product comprising the high-performance polyethylene fiber according to any one of claims 1 to 9.

11. Radiocarbon (C) using Accelerator Mass Spectrometer (AMS) １４ ) measurement, at a temperature 10°C or more higher than the melting point of the resin composition; supplying the melt-extruded resin composition to a spinning nozzle at a temperature 80°C or more higher than the melting point of the resin composition; cooling the fibrous material discharged from the spinning nozzle and then winding it up at a speed of 25 m / min or more; and stretching the fibrous material obtained at a temperature equal to or lower than the melting point of the fibrous material at least once, to a draw ratio of 5 times or more.

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