Method for manufacturing glass filaments and glass yarns

Abstract

The present invention provides a method for manufacturing a glass filament that generates less broken yarn when stretched into a glass fiber, and a method for manufacturing a glass yarn that generates less broken yarn and fuzz when twisted, and has less quality deviation at the start and end of winding. The method for manufacturing a glass filament includes: (1) a stretching step in which a raw yarn formed from a glass composition containing 90% or more of SiO2 by mass is stretched into a glass fiber under conditions in which the melting temperature is 1,500 to 3,500°C and the tension is 0.1 to 1.0 cN per root; and (2) a bundling step in which 30 to 400 of the glass fibers obtained in the stretching step are bundled to manufacture a glass filament.

Description

Technical Field

[0001] This invention relates to a method for manufacturing glass strands and glass yarns. Background Technology

[0002] In recent years, with the popularization of fifth-generation mobile communication systems (5G) and the development and production of Internet of Things (IoT) devices, there is a need for high-performance printed circuit boards (PCBs) capable of handling high-speed information processing and high-frequency communication. Therefore, glass cloth used in PCBs requires lower dielectric loss to better suppress signal degradation.

[0003] Compared to ordinary glass fibers, glass fibers with higher SiO2 content are known to have superior dielectric properties. In particular, high-purity quartz glass fibers composed of SiO2 have very low dielectric loss due to their small relative permittivity and dielectric loss tangent, and are expected to expand their application as glass cloths for printed wiring substrates.

[0004] Patent document 1 proposes a method for manufacturing quartz glass fibers by heating and stretching using a mixed flame of oxygen and hydrogen, while patent document 2 proposes a method for heating and stretching by irradiating with a laser.

[0005] However, quartz glass fiber is a rigid yet fragile material, and compared to E glass fiber, it is prone to fuzzing and yarn breakage. This problem is not shown in Patent Documents 1 and 2, and suppressing fuzzing and improving weavability remain unresolved technical issues. In particular, long glass yarns exceeding 100 km in length have consistently exhibited quality deviations at the beginning and end of the winding process.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2006-282401 Patent Document 2: Japanese Patent Application Publication No. 2022-173836 Summary of the Invention

[0007] (a) Technical problems to be solved The present invention was made in view of the above circumstances, and its object is to provide: a method for manufacturing glass filaments that produce fewer yarn breaks when stretched into glass fibers; and a method for manufacturing glass yarns that produce fewer yarn breaks and fuzzing during twisting, and whose long glass yarns have smaller quality deviations between the beginning and end of winding.

[0008] (II) Technical Solution To solve the above-mentioned technical problems, the present invention provides a method for manufacturing glass precursor fibers, characterized in that it comprises: (1) A stretching process, wherein, under conditions of a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / fiber, a raw yarn formed from a glass composition is stretched into glass fibers, the glass composition containing 90% by mass or more of SiO2; and (2) Bundling process, wherein 30 to 400 glass fibers obtained in the stretching process are bundled together to manufacture glass filament.

[0009] If the glass filament manufacturing method of the present invention is to stretch it into glass fiber under the conditions of melting temperature of 1,500~3,500°C and tension of 0.1~1.0 cN / fiber, a method for manufacturing glass filament with less yarn breakage during stretching into glass fiber can be provided.

[0010] Furthermore, quartz glass containing 99% by mass or more of SiO2 is preferably used as the glass composition.

[0011] The glass composition is preferably used.

[0012] Furthermore, it is preferable to use a method selected from burner flame, laser, and electric furnace to melt the raw yarn formed from the glass composition.

[0013] Preferably, the melting method for the raw yarn formed from the glass composition is this melting method.

[0014] Furthermore, the fuel gas used as the burner flame is preferably a mixture of hydrogen, oxygen, and nitrogen, wherein the mixing ratio of the mixture is hydrogen:oxygen = 1:1 to 3:1, and the mixing ratio of nitrogen is less than 1 relative to oxygen (1).

[0015] This fuel gas is preferably used in the fuel gas of the burner flame.

[0016] Furthermore, the laser source for the laser can be selected from carbon dioxide gas systems, yttrium aluminum garnet (YAG) systems, Nd / glass, Nd / vanadate, diodes, optical fibers, disks, HeCd, copper vapor lasers, iodine lasers, argon lasers, krypton lasers, and chemical lasers.

[0017] This type of laser source is preferably used in the laser source of the laser.

[0018] Furthermore, the heating element of the electric furnace can be made of materials selected from platinum, molybdenum, tantalum, tungsten, molybdenum disilicide, lanthanum chromite, and carbon graphite.

[0019] The heating element of the electric furnace is preferably made of this material.

[0020] Furthermore, the present invention provides a method for manufacturing glass yarn, which includes a twisting process in which glass filament manufactured by the above method is twisted by 0.1 to 5 turns per 25 mm.

[0021] If this method of manufacturing glass yarn is used, glass yarn with less yarn breakage and less fuzzing can be produced during twisting.

[0022] Furthermore, the present invention provides a method for manufacturing glass yarn, which includes a winding process of winding the glass yarn obtained in the twisting process into a winding bobbin, and the length of the glass yarn is set to be 100 km or more.

[0023] If this method of manufacturing glass yarn is used, long strips of glass yarn with stable quality can be produced.

[0024] (III) Beneficial Effects As described above, the method for manufacturing the glass filament of the present invention provides a glass filament that exhibits less yarn breakage and excellent tensile properties when stretched into glass fibers. Furthermore, using the glass filament manufactured by the above method provides a method for manufacturing glass yarn that produces less yarn breakage and fuzzing during twisting and has smaller quality deviations. Detailed Implementation

[0025] As mentioned above, there is a need to develop: a method for manufacturing glass filaments that produce fewer yarn breaks when stretched into glass fibers; and a method for manufacturing glass yarns that produce fewer yarn breaks and fuzz in long strips of glass yarn, and have smaller quality deviations between the start and end of winding.

[0026] The inventors of this application conducted in-depth research on the above-mentioned technical problems and found that if the conditions of the stretching process for stretching into glass fibers are set to a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / strand, the winding tension during the stretching process can be suppressed, thereby suppressing the occurrence of yarn breakage during stretching into glass fibers. In addition, it was found that by using the glass yarn manufacturing method of glass fibers manufactured by the above method, the occurrence of yarn breakage and fuzzing during twisting can be suppressed, especially in long glass yarns of 100 km or more, glass yarns with small mass deviation between the start and end of winding are obtained, thus completing the present invention.

[0027] That is, the present invention is a method for manufacturing glass precursor fibers, characterized in that it comprises: (1) A stretching process, wherein, under conditions of a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / fiber, a raw yarn formed from a glass composition is stretched into glass fibers, the glass composition containing 90% by mass or more of SiO2; and (2) Bundling process, wherein 30 to 400 glass fibers obtained in the stretching process are bundled together to manufacture glass filament.

[0028] Furthermore, the present invention provides a method for manufacturing glass yarn, characterized in that it includes a twisting process in which glass filament manufactured by the method described above is twisted by 0.1 to 5 turns per 25 mm.

[0029] The present invention will be described in detail below, but the present invention is not limited thereto.

[0030] [Manufacturing method of glass precursor] (1) Stretching process The glass fiber manufacturing method of the present invention includes a stretching step in which a raw yarn formed from a glass composition is stretched into glass fibers under conditions of a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / fiber, wherein the glass composition contains 90% by mass or more of SiO2. The glass fibers manufactured in this stretching step are obtained by melting and stretching the raw yarn formed from the glass composition described above. The glass composition contains 90% by mass or more of SiO2. Preferably, the glass composition contains 95% to 100% by mass of SiO2, and examples include naturally occurring quartz with fewer impurities or synthetic quartz made from silicon tetrachloride. If the SiO2 content is less than 90% by mass, electrical properties such as the dielectric loss tangent will deteriorate due to the other components.

[0031] In particular, quartz glass containing 99% by mass or more of SiO2 is preferably used as the glass composition.

[0032] To prevent malfunctions caused by radiation, the content of U or Th, which are impurities, in the glass composition is more preferably 0.1 ppb or less. By using this glass composition, glass cloth with U and Th contents of 0.1 ppb or less can be obtained. The concentration of the above-mentioned impurities can be determined by atomic absorption spectrophotometry, inductively coupled plasma (ICP) emission spectrometry, or the like.

[0033] The aforementioned raw yarn can be either filamentous or rod-shaped, and its diameter is preferably 100~500μm, more preferably 200~400μm.

[0034] As conditions for stretching the aforementioned raw yarn into glass fibers, the melting temperature is 1,500 to 3,500°C, preferably 1,700 to 3,300°C, more preferably 2,000 to 3,000°C, and even more preferably 2,200 to 2,800°C. If the measured temperature of the melting portion is below 1,500°C, the viscosity at the time of melting is high, the tension during stretching increases, and the tensile strength ratio decreases due to tight winding. In particular, the tensile strength decreases significantly at the end of the glass yarn winding (the beginning of the winding process). Furthermore, if the temperature exceeds 3,500°C, the glass composition melts excessively, resulting in yarn breakage and unstable stretching. In addition, in this specification, the melting temperature refers to the temperature obtained by measuring the melting portion using a two-color thermal imaging temperature measuring instrument (Thermera manufactured by Nobby Tech. Ltd.) with an exposure time of 8 seconds and a frame rate of 4.99 fps.

[0035] Furthermore, the tension when stretching the glass fibers described above is 0.1~1.0 cN / fiber, preferably 0.1~0.7 cN / fiber, and more preferably 0.1~0.5 cN / fiber. If the tension is below 0.1 cN / fiber, it is difficult to stretch stably, and the winding becomes loose, which can easily lead to the shedding of glass fibers and breakage of the yarn during the twisting process; if the tension exceeds 1.0 cN / fiber, the winding becomes tight, and the tensile strength ratio will decrease. In addition, in this invention, the tension of the glass fibers is calculated by measuring the glass filaments being wound using a digital tension meter (ZEF-100 manufactured by SCHMIDT Corporation) and dividing by the number of bundled fibers.

[0036] Preferably, the melting method of the raw yarn used in the stretching process is set to use any one of burner flame, laser and electric furnace.

[0037] The fuel gas for the burner flame can include methane, propane, propylene, ethylene, acetylene, and hydrogen. From the perspective of carbon neutrality, hydrogen is preferred.

[0038] When hydrogen is used as the above-mentioned fuel gas, the fuel gas is preferably a mixture of hydrogen, oxygen and nitrogen, more preferably a fuel gas in which hydrogen:oxygen = 1:1 to 3:1, and the mixing ratio of nitrogen to oxygen is 1 or less relative to 1.

[0039] The gas mixing methods described above include nozzle mixing, which mixes at the burner nozzle, and premixing, which mixes near the burner nozzle. Premixing, which can make the flame temperature uniform, is preferred.

[0040] If the laser source of the above-mentioned laser has a wavelength of 0.7~100μm, there are no special restrictions. For example, laser sources selected from carbon dioxide gas system, YAG system, Nd / glass, Nd / vanadate, diode, optical fiber, disk, HeCd, copper vapor laser, iodine laser, argon laser, krypton laser and chemical laser can be used.

[0041] Among them, carbon dioxide gas laser with a wavelength of 10.6 μm, Nd-doped YAG laser with a wavelength of 1.06 μm or yttrium vanadate (YVO) laser are particularly preferred because carbon dioxide gas laser has higher power and can heat glass in a short time.

[0042] The material used for the heating element of the aforementioned electric furnace is preferably selected from platinum, molybdenum, tantalum, tungsten, molybdenum disilicide, lanthanum chromite, and carbon graphite. Among these, carbon graphite is further preferred because it can heat glass in a short time.

[0043] The method for stretching the glass fiber of the present invention is not particularly limited. For example, the rod method in which the raw yarn of the glass composition is heated and melted while one end is stretched and wound up, the direct melt method in which the glass composition is melted in a crucible and flows out from a plurality of small holes provided at the bottom of the crucible and wound up, and the marble melt method are all examples. When the glass composition is a quartz glass composition with a high melting temperature, the rod method is preferred.

[0044] The stretch ratio of the glass fiber is preferably 50 to 30,000 times, and more preferably 250 to 20,000 times.

[0045] (2) Bundling process The glass fiber manufacturing method of the present invention includes a bundling process in which 30 to 400 glass fibers obtained in the stretching process are bundled together to manufacture glass fiber.

[0046] The number of glass fibers bundled in the above stretching process is 30 to 400. This number of fibers can reduce or eliminate the number of yarn-binding steps, thus improving productivity.

[0047] When bundling the glass fibers described above, a bundling agent is preferably used.

[0048] The aforementioned bridging agent preferably comprises one or more bridging agents selected from starch, urethane resin, and vinyl acetate resin, and may include other components as needed.

[0049] Examples of starches mentioned above include those derived from corn, wheat, rice, potatoes, sweet potatoes, cassava, sago, kudzu root, bracken, lotus root, or legumes. Corn starch and rice starch with smaller particle sizes are preferred, rice starch is more preferred, and japonica rice starch is even more preferred. One type of starch may be used alone, or two or more may be used in combination. Furthermore, the starches mentioned above can be unprocessed or processed. Processed starches are not particularly limited, and examples include acetylated distarch adipate, acetylated distarch phosphate, acetylated starch oxide, acetate starch, oxidized starch, hydroxypropyl starch, hydroxypropyl distarch phosphate, phosphorylated distarch phosphate, distarch phosphate, pregelatinized starch, and heat-treated starch.

[0050] The aforementioned urethane resin is not particularly limited to being a reaction product of a polyester or polyether with an isocyanate. Examples of polyesters include esters of adipic acid, sebacic acid, and ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,3-butanediol, trimethylolpropane, etc. Examples of polyethers include polypropylene glycol and polyethylene glycol. Examples of isocyanates include hexamethylene diisocyanate. These substances can be used alone or in combination of two or more.

[0051] Examples of vinyl acetate resins include anionic vinyl acetate, cationic vinyl acetate, and nonionic vinyl acetate, with cationic vinyl acetate being preferred.

[0052] Other components mentioned above may include, for example, lubricants, antistatic agents, emulsifiers, softeners, film-forming agents, preservatives, and silane coupling agents. Additionally, small amounts of alcohols such as methanol, ethanol, and isopropanol, or other organic solvents, may be added.

[0053] Examples of such lubricants include tallow, modified silicone oil, soybean oil, coconut oil, rapeseed oil, palm oil, sesame oil, paraffin wax, and ester condensates of higher saturated fatty acids and higher saturated alcohols. Animal and vegetable oils may also be hydrogenated oils.

[0054] Examples of antistatic agents include anionic surfactants, cationic surfactants, amphoteric surfactants, ionic antistatic agents, nonionic antistatic agents, ionic liquids, conductive polymers, and carbon particles. Ionic antistatic agents are preferred, and cationic surfactants are more preferred. Examples of cationic surfactants include tertiary amines and quaternary ammonium salts. Quaternary ammonium salts with high water solubility are even more preferred.

[0055] Examples of emulsifiers mentioned above include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0056] Examples of such softeners include amides, imidazolines, tetraethylenepentamine, and condensates of polyethyleneimine and stearic acid.

[0057] In addition to starch, urethane resin, and vinyl acetate resin, other examples of film-forming agents include polyethylene glycol and polyvinyl iodine.

[0058] Formalin and tributyltin oxide are examples of the aforementioned preservatives.

[0059] Examples of silane coupling agents include: trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenylmethylvinylethoxysilane, naphthyltrimethoxysilane, naphthyltriethoxysilane, and 1,4-bis(methoxydimethylsilane). (B)benzene, tetramethoxysilane, tetraethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidyletheroxypropyltrimethoxysilane, 3-glycidyletheroxypropylmethyldimethoxysilane, 3-glycidyletheroxypropyltriethoxysilane, 3-glycidyletheroxypropylmethyldiethoxysilane 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-( 2-Aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane and its hydrochloride, N-(vinylbenzyl)-2-aminoethyl-3-aminopropylmethyldiethoxysilane and its hydrochloride, 3-isocyanate propyltriethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane.

[0060] There are no particular limitations on the method of applying the above-mentioned slugging agent to glass fiber. Examples include spray coating using a sprayer, roller or belt coating, and impregnation coating.

[0061] [Method for manufacturing glass yarn] (3) Twisting process The preferred method for manufacturing glass yarn includes a twisting process in which glass filaments manufactured by the method are twisted by 0.1 to 5 turns per 25 mm.

[0062] Glass yarn is obtained by twisting the glass filaments obtained in the above-mentioned bundling process using a twisting machine. The preferred twist number for the glass yarn is 0.1 to 5 turns per 25 mm, more preferably 0.5 to 1.0 turns per 25 mm. If the twist number is low, the fabric thickness will easily decrease during the fiber opening process after the glass cloth is made, and air permeability will easily be reduced. Furthermore, if the twist number is high, the yarn's bundling property is improved, and breakage and pilling are less likely to occur during weaving. If the twist number is 0.1 turns or more, breakage and pilling are less likely to occur during weaving. If the twist number is 5 turns or less, the following advantages are available: the force that causes the yarn to recover in the opposite direction of twisting is suppressed, and adjacent yarns will not tangle during warping, allowing for stable warping.

[0063] In addition, in this specification, the above-mentioned bundling process and the above-mentioned twisting process are sometimes collectively referred to as the twisting process.

[0064] Furthermore, the aforementioned method for manufacturing glass yarn preferably includes a winding process after the twisting process, in which the obtained glass yarn is wound onto a winding bobbin, and the length of the glass yarn is 100 km or more. Even with such a long glass yarn, the manufacturing method of the present invention can produce glass yarn with stable quality at both the beginning and end of winding. Specifically, the tensile strength Ts at the beginning of winding and the tensile strength Te at the end of winding in the length direction of the glass yarn are preferably in the range of Te / Ts = 0.5 to 2.0, more preferably in the range of 0.7 to 1.3. If within this range, the overall quality of the glass yarn wound onto the winding bobbin can be considered uniform.

[0065] Example The following examples and comparative examples illustrate the present invention in detail, but the present invention is not limited to the following examples.

[0066] The measurements in the examples were performed using the following methods.

[0067] [Melting Temperature] The measurements were taken using a two-color thermal imaging temperature measuring instrument (Thermera manufactured by Nobby Tech. Ltd.) with an exposure time of 8 seconds and a frame rate of 4.99fps.

[0068] [tension] The tension of the glass fiber is measured by using a digital tension meter (ZEF-100 manufactured by SCHMIDT) to measure the glass fiber being wound under the condition that the fiber path of the glass fiber is horizontal, and then divided by the number of bundled fibers.

[0069] Tensile strength According to section 7.4.3 of Japanese Industrial Standard (JIS) R 3420:2013, measurements were performed using an Autograph (AGS-50NX manufactured by Shimadzu Corporation). The tensile strength at the beginning of winding along the length of the glass yarn was defined as Ts, and the tensile strength at the end of winding was defined as Te. The deviation was evaluated using Te / Ts.

[0070] [Example 1] A glass fiber filament binder was prepared, consisting of 3.0% by mass starch, 0.5% by mass tallow, 0.1% by mass emulsifier, and the balance water. For a 230 μm diameter raw yarn formed from a quartz glass ingot, an oxyhydrogen flame premixed with hydrogen, oxygen, and nitrogen in a ratio of 2.6:1:0.05 was used. The melting temperature was set to 2522°C, and the raw yarn was stretched at a stretch ratio of 3306 times to produce glass fibers with an average diameter of 4 μm. The quartz glass ingot contained 99.9% by mass SiO2. The stretch ratio was determined based on the ratio of the feed rate to the glass fiber winding rate. The filament binder was then applied to the glass fibers using a coater, and 100 fibers were bundled together to form a glass filament. This filament was then twisted 0.6 turns per 25 mm to obtain a glass yarn. The tension during stretching was 0.45 cN / fiber, and the tensile strength ratio was Te / Ts = 0.9.

[0071] [Example 2] Using the same glass fiber slub and raw yarn as in Example 1, the raw yarn was irradiated with a carbon dioxide gas laser with a diameter of 3.5 mm, a wavelength of 10.6 μm, and a power of 22.2 W. The melting temperature was set to 2688°C, and the raw yarn was stretched at a stretch ratio of 3306 to produce glass fibers with an average diameter of 4 μm. The glass fiber slub was then coated with the glass fiber slub using a coater, and 100 of these glass fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 0.40 cN / fiber, and the tensile strength ratio was Te / Ts = 1.0.

[0072] [Example 3] Using the same glass fiber slub and raw yarn as in Example 1, the raw yarn was heated in an electric furnace with a carbon graphite heating element to a melting temperature of 2437°C. The raw yarn was stretched at a draw ratio of 3306 to produce glass fibers with an average diameter of 4 μm. The glass fiber slub was then coated with the slub using a coater, and 100 fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The draw ratio was determined based on the ratio of the feed speed to the glass fiber winding speed. The tension during stretching was 0.50 cN / fiber, and the tensile strength ratio was Te / Ts = 0.8.

[0073] [Example 4] Using the same glass fiber slub and raw yarn as in Example 1, a hydrogen-oxygen flame premixed with hydrogen, oxygen, and nitrogen in a ratio of 2.6:1:0.05 was used to set the melting temperature to 2563°C. The raw yarn was stretched at a stretch ratio of 529 times to produce glass fibers with an average diameter of 10 μm. The slub was then coated onto the glass fibers using a coater, and 200 fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 0.18 cN / fiber, and the tensile strength ratio was Te / Ts = 1.0.

[0074] [Example 5] Using the same glass fiber slub and raw yarn as in Example 1, the raw yarn was irradiated with a carbon dioxide gas laser with a diameter of 3.5 mm, a wavelength of 10.6 μm, and a power of 22.2 W. The melting temperature was set to 2799°C, and the raw yarn was stretched at a stretch ratio of 529 times to produce glass fibers with an average diameter of 10 μm. The glass fiber slub was then coated with the glass fiber slub using a coater, and 200 of these glass fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 0.16 cN / fiber, and the tensile strength ratio was Te / Ts = 1.0.

[0075] [Example 6] Using the same glass fiber sizing agent and raw yarn as in Example 1, the raw yarn was heated in an electric furnace with a carbon graphite heating element to a melting temperature of 2484°C. The raw yarn was stretched at a stretch ratio of 529 to produce glass fibers with an average diameter of 10 μm. The glass fiber sizing agent was then applied to the glass fibers using a coater, and 200 fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 0.30 cN / fiber, and the tensile strength ratio was Te / Ts = 1.0.

[0076] [Comparative Example 1] Using the same glass fiber slub and raw yarn as in Example 1, the raw yarn was irradiated with a carbon dioxide gas laser with a diameter of 3.5 mm, a wavelength of 10.6 μm, and a power of 34 W. The melting temperature was set to 3790 °C, and the raw yarn was stretched at a stretch ratio of 3306 to produce glass fibers with an average diameter of 4 μm. The glass fiber slub was then coated with the glass fiber slub using a coater, and 100 of these glass fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 0.03 cN / fiber, and the tensile strength ratio was Te / Ts = 1.0.

[0077] [Comparative Example 2] Using the same glass fiber slub and raw yarn as in Example 1, the raw yarn was heated in an electric furnace with a carbon graphite heating element to a melting temperature of 1,400°C. The raw yarn was stretched at a draw ratio of 529 to produce glass fibers with an average diameter of 10 μm. The glass fiber slub was then coated with the slub using a coater, and 200 fibers were bundled together to form a glass filament. Each 25 mm section was twisted 0.6 turns to obtain a glass yarn. The draw ratio was determined based on the ratio of the feed speed to the glass fiber winding speed. The tension during stretching was 2.00 cN / fiber, and the tensile strength ratio was Te / Ts = 0.3.

[0078] [Comparative Example 3] Using the same glass fiber sizing agent and raw yarn as in Example 1, the raw yarn was heated in an electric furnace with a carbon graphite heating element to a melting temperature of 1,700°C. The raw yarn was stretched at a stretch ratio of 529 to produce glass fibers with an average diameter of 10 μm. The glass fiber sizing agent was then applied to the glass fibers using a coater, and 200 fibers were bundled together to form a glass filament. This filament was then twisted 0.6 turns every 25 mm to obtain a glass yarn. The stretch ratio was determined based on the ratio of the supply speed to the glass fiber winding speed. The tension during stretching was 1.40 cN / fiber, and the tensile strength ratio was Te / Ts = 0.4.

[0079] The glass filaments and glass yarns obtained in each embodiment and comparative example were evaluated as follows. The results are shown in Table 1.

[0080] 1. Tensile properties When the raw yarn is stretched into glass fiber with a length of 100km, the case where yarn breakage occurs in 4 or fewer out of 10 batches is marked as "○", and the case where yarn breakage occurs in 5 or more out of 10 batches is marked as "×".

[0081] 2. Yarn breakage during the twisting process When glass filaments with a length of 100km are bundled together in the number of strands described in the above embodiments and comparative examples, and then twisted under the above conditions to produce glass yarn, the case where no yarn breakage occurs is marked as "○", and the case where yarn breakage occurs midway is marked as "×".

[0082] 3. Visual inspection of glass yarn By observing the surface of the glass yarn wound on the spool with a magnifying glass and shining light on it from the side, the amount of surface fuzz can be measured visually.

[0083] [Table 1] According to Table 1 above, the evaluation results of Examples 1 to 6 using glass filaments and glass yarns manufactured by the method of the present invention are all good. On the other hand, regarding Comparative Examples 1 to 3 manufactured under conditions that are not the manufacturing method of the present invention, in Comparative Example 1, more yarn breaks occurred when stretching into glass fibers. In Comparative Example 2, more yarn breaks occurred when producing glass yarns, and more surface fuzz was observed during visual inspection, and the tensile strength ratio was also significantly reduced. In Comparative Example 3, more yarn breaks occurred when producing glass yarns, and more surface fuzz was observed during visual inspection. That is, it was found that by stretching under conditions of a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / thread, glass filaments with fewer yarn breaks can be manufactured, and by using glass filaments manufactured by the above method, glass yarns with small quality deviations can be obtained even in long glass yarns of 100 km or more.

[0084] This manual includes the following solutions: [1] A method for manufacturing glass fiber, characterized in that it comprises: (1) A stretching process, wherein, under conditions of a melting temperature of 1,500 to 3,500°C and a tension of 0.1 to 1.0 cN / fiber, a raw yarn formed from a glass composition is stretched into glass fibers, the glass composition containing 90% by mass or more of SiO2; and (2) Bundling process, wherein 30 to 400 glass fibers obtained in the stretching process are bundled together to manufacture glass filament.

[0085] [2] The method for manufacturing glass fiber as described in [1] is characterized in that, as the glass composition, quartz glass containing 99% by mass or more of SiO2 is used.

[0086] [3] The method for manufacturing glass filament as described in [1] or [2] is characterized in that the melting method of the filament formed from the glass composition is set to use a method selected from any one of burner flame, laser and electric furnace.

[0087] [4] The method for manufacturing glass filament as described in [3] is characterized in that the fuel gas used as the fuel gas for the burner flame is a mixture of hydrogen, oxygen and nitrogen, wherein the mixing ratio of the mixture is hydrogen:oxygen = 1:1 to 3:1, and the mixing ratio of nitrogen is less than 1 relative to oxygen of 1.

[0088] [5] The method for manufacturing glass fiber as described in [3] is characterized in that, as the laser source of the laser, a laser source selected from carbon dioxide gas system, YAG system, Nd / glass, Nd / vanadate, diode, optical fiber, disk, HeCd, copper vapor laser, iodine laser, argon laser, krypton laser and chemical laser is used.

[0089] [6] The method for manufacturing glass filament as described in [3] is characterized in that the material used as the heating element of the electric furnace is selected from platinum, molybdenum, tantalum, tungsten, molybdenum disilicide, lanthanum chromite and carbon graphite.

[0090] [7] A method for manufacturing glass yarn, characterized in that it includes a twisting process, wherein glass filament manufactured by any one of [1] to [6] is twisted by 0.1 to 5 turns per 25 mm.

[0091] [8] The method for manufacturing glass yarn as described in [7] is characterized in that it includes a winding process of winding the glass yarn obtained in the twisting process into a winding bobbin, and the length of the glass yarn is set to be 100 km or more.

[0092] Furthermore, this invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any technical solution having a substantially identical structure and achieving the same technical effect as the technical concept described in the claims of this invention is included within the technical scope of this invention.

Claims

1. A method for manufacturing glass precursor fibers, characterized in that, It includes: (1) A stretching process, wherein, under conditions of a melting temperature of 1,500~3,500°C and a tension of 0.1~1.0 cN / fiber, a raw yarn formed from a glass composition is stretched into glass fibers, wherein the glass composition contains 90% by mass or more of SiO2; and (2) Bundling process, wherein 30 to 400 glass fibers obtained in the stretching process are bundled together to manufacture glass filament.

2. The method for manufacturing glass precursor according to claim 1, characterized in that, The glass composition used is quartz glass containing 99% by mass or more of SiO2.

3. The method for manufacturing glass precursor according to claim 1, characterized in that, The melting method for the raw yarn formed from the glass composition is set to use any one of burner flame, laser and electric furnace.

4. The method for manufacturing glass precursor according to claim 3, characterized in that, The fuel gas used as the fuel gas for the burner flame is a mixture of hydrogen, oxygen and nitrogen, wherein the mixing ratio of the mixture is hydrogen:oxygen = 1:1 to 3:1, and the mixing ratio of nitrogen is less than 1 relative to oxygen.

5. The method for manufacturing glass precursor according to claim 3, characterized in that, As the laser source, a laser source selected from carbon dioxide gas system, YAG system, Nd / glass, Nd / vanadate, diode, optical fiber, disk, HeCd, copper vapor laser, iodine laser, argon laser, krypton laser and chemical laser is used.

6. The method for manufacturing glass precursor according to claim 3, characterized in that, The heating element of the electric furnace is made of a material selected from platinum, molybdenum, tantalum, tungsten, molybdenum disilicide, lanthanum chromite, and carbon graphite.

7. A method for manufacturing glass yarn, characterized in that, It includes a twisting process in which glass filament manufactured by any one of claims 1 to 6 is twisted by 0.1 to 5 turns per 25 mm.

8. The method for manufacturing glass yarn according to claim 7, characterized in that, The process includes a winding process in which the glass yarn obtained in the twisting process is wound onto a winding bobbin, and the length of the glass yarn is set to be 100 km or more.

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