JP6080010B2 - Glass fiber composition, glass fiber, and method for producing glass fiber - Google Patents

Description

  The present invention relates to a glass fiber used as a reinforcing material for a composite material, and a manufacturing method thereof.

Glass fibers (also referred to as glass fibers) used in composite materials are generally formed and spun using a molding device generally called a bushing (also referred to as a platinum heating container) having a substantially rectangular appearance. It is manufactured. The bushing device is a pot-shaped container that can temporarily retain molten glass, and is made of a heat-resistant metal material such as platinum. In addition, a large number of nozzles (bushing nozzles) are provided at the bottom. With this bushing device, the temperature of the molten glass is controlled at the tip of the bushing nozzle so that the molten glass has an optimum temperature, specifically, a value in the vicinity of a temperature corresponding to 10 ³ dPa · s (molding temperature Tx). Pull out continuously from the nozzle and mold into a filament. The monofilaments formed in this way are bundled into a predetermined number to obtain glass fibers (long glass fibers).

  When molding such glass fibers, if the liquid phase temperature Ty of the molten glass is equal to or higher than the molding temperature Tx, crystals that cause devitrification near the bushing nozzle are likely to precipitate in the molten glass. As a result, the bushing nozzle is clogged, causing thread breakage called break. For this reason, it is preferable that the temperature difference ΔTxy between the liquidus temperature Ty and the spinning temperature of the molten glass is larger and the devitrification temperature Ty is lower.

  On the other hand, in the manufacture of glass fibers, attempts have been made to reduce the content of boron (B) in the glass composition in consideration of the problem of environmental pollution. Furthermore, since the raw material used as a supply source of boron is expensive, it is important to reduce the boron content in the glass composition in order to achieve a reduction in the glass fiber cost. From this point of view, Patent Document 1, Patent Document 2 or Patent Document 3 all attempt to achieve this object by limiting the glass composition.

  Further, in applications that are used for functional members that require fine structure control, there is an increasing demand for fine glass fiber products. For example, in printed wiring boards, etc., conductive holes of 0.1 mm or less (via holes or vias, through holes, inner via holes, blind via holes, via holes, etc.) that connect any conductor layer provided via an insulating base material. It is found that it is preferable to use fine count glass fibers as the glass fibers constituting the base material in order to perform such high-precision processing on the substrate. doing.

  In order to spin glass fibers with fine count, the bushing nozzle diameter should be reduced. However, the thinner the nozzle diameter, the more likely the problem of nozzle creep deformation and the shorter the service life of the bushing base plate. There is a problem of becoming. In order to avoid such a problem, Patent Document 4 and Patent Document 5 disclose inventions that limit the shapes of bushings and nozzles. Further, in the glass fiber molding by the bushing as described above, clogging of the nozzle leads to fiber cutting, which lowers the product yield, so it is important to prevent it. Therefore, Patent Document 6 discloses an invention in which a weir is provided to prevent inhomogeneous foreign matter from flowing into the nozzle.

JP 2000-247684 A JP 2005-29465 A Special table 2003-500330 gazette JP-A-5-279072 JP 7-215729 A Japanese Patent Laid-Open No. 9-142871

  However, it is difficult to achieve a sufficiently high effect only by various improvements made so far, and there is room for further improvement. For example, the glass manufacturing industry is an industry that consumes a great deal of energy, and it is necessary to reduce the high temperature viscosity of the glass. In addition, when the high-temperature viscosity of the glass is high, there is a problem that the melting temperature is increased, and the refractory erosion of the melting kiln is increased, thereby shortening the lifetime of the kiln. Since waste refractories generated by refurbishment of the kiln are landfilled, the environment is burdened anyway. In order to improve the meltability, it is often necessary to take measures such as greatly increasing the capacity of the production facility, and as a result, there is a problem that the total production cost becomes high. In addition, there is a limit to the change in the equipment performed to cope with the fine count because there is a factor that shortens the equipment life of the base plate of the bushing. In addition, such a change in equipment newly causes the following manufacturing problems that were not assumed in the past. For example, when the diameter of the bushing nozzle is reduced, even fine foreign matters and devitrification of molten glass, which have not been regarded as problems in the past, cause thread breakage. Further, regarding the efforts to realize a glass composition that can solve such problems, in addition to the conventional fiber diameter, it is not possible to easily form a glass monofilament having a finer count.

  Under such circumstances, the inventors of the present invention have an object to provide a composition for glass fiber that facilitates the production of the above-described problems, in particular, a fine count glass monofilament.

  As a result of various studies, the present inventors have found that the above problems can be solved by adding a small amount of SrO and BaO as a glass composition, and propose the present invention.

That is, the glass fiber composition of the present invention, _SiO 2 _50-60% by mass percentage of oxide _{equivalent, Al 2 O 3 10~16%,} B 2 O 3 0~8%, 0~5% MgO, CaO 16~30%, SrO 0.1~2%, BaO 0.1~2%, MgO + CaO + SrO + BaO 22~30%, Na 2 O 0~2%, K 2 O 0~2%, Li 2 O + Na 2 O + K 2 O 0 to _2%, characterized in that it contains _P 2 O 5 _0~3%. Here, “MgO + CaO + SrO + BaO” means the total content of MgO, CaO, SrO and BaO. “Li ₂ O + Na ₂ O + K ₂ O” means the total content of Li ₂ O, Na ₂ O and K ₂ O.

  According to the above configuration, productivity is not impaired, and a decrease in manufacturing yield can be effectively suppressed due to yarn breakage or the like even when manufacturing a fine count glass fiber.

In the present invention, it is preferable that the molding temperature Tx is 1250 ° C. or lower and the liquidus temperature Ty is 1130 ° C. or lower. Here, the “forming temperature Tx” means a temperature at which the viscosity of the glass is 10 ³ dPa · s. “Liquid phase temperature Ty” means a temperature at which a specific crystal phase is generated as an initial phase.

  According to the said structure, since it can spin at low temperature, it becomes possible to reduce the load with respect to an installation. Moreover, it becomes easy to maintain a state in which no crystal is precipitated in the molten glass during the molding of the glass monofilament.

  In the present invention, the temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty is preferably 100 ° C. or higher.

  According to the above configuration, devitrification near the bushing nozzle is less likely to occur, and yarn breakage can be effectively suppressed. This makes it easy to achieve stable glass fiber molding, particularly continuous molding of fine glass fibers.

  The glass fiber of the present invention is characterized by comprising the glass fiber composition described above. In the present invention, “glass fiber” refers to a collective term for a plurality of glass monofilaments, and the form thereof is not limited.

  In the present invention, any form of chopped strands, yarns, and rovings is preferable.

  The glass fiber-containing composite material of the present invention is characterized in that the above-described glass fiber is combined with an organic medium, concrete, or mortar.

  According to the said structure, it becomes possible to achieve the stable physical strength over a long period which was not realizable with organic medium, concrete, or mortar alone.

Process for producing a glass fiber of the present invention, _SiO 2 _50-60% by mass percentage of oxide _{equivalent, Al 2 O 3 10~16%,} B 2 O 3 0~8%, 0~5% MgO, CaO 16~30%, SrO 0.1~2%, BaO 0.1~2%, MgO + CaO + SrO + BaO 22~30%, Na 2 O 0~2%, K 2 O 0~2%, Li 2 O + Na 2 O + K 2 O ) A glass raw material is prepared so as to be a glass containing 0 to 2% and P ₂ O ₅ 0 to 3%, melted, and then spun to form glass fibers.

  In the present invention, it is preferable to perform spinning while measuring and managing within a range of ± 20 ° C. with respect to the target molding temperature.

  According to the said structure, it becomes possible to achieve a high dimensional quality by interlocking with the system which copes with the temperature fluctuation at the time of shaping | molding.

  Hereinafter, the reason for limiting the composition range of each component as described above for the glass fiber composition of the present invention will be described. In the following description, unless otherwise specified,% display means mass%.

SiO ₂ is a component that forms a skeletal structure of oxide glass and greatly contributes to the strength and basic chemical durability of the glass article and the viscosity at the time of melting. When the content of SiO ₂ is small, the mechanical strength of the glass fiber is lowered. Further, if the content of SiO ₂ is large, the viscosity of the molten glass becomes too high, so that it becomes difficult to obtain a homogeneous molten state. As a result, there is a possibility that the glass fiber diameter is difficult to adjust and difficult to mold. growing. The preferable range of the content of SiO ₂ is 50 to 57%, more preferably 51 to 55% , and most preferably 52 to 55% .

Al ₂ O ₃ is a component that improves the initial solubility of the glass and also has an effect of improving devitrification. Devitrification tendency of the glass with a low content of Al ₂ O ₃ is increased. Moreover, when the content of Al ₂ O ₃ increases, the viscosity of the glass becomes high, but not as high as SiO ₂ , and there is a concern that problems such as molding may occur. The preferable range of the content of Al ₂ O ₃ is 10 to 14%, more preferably 11 to 14%, and most preferably 12 to 14%.

B ₂ O ₃ is a component having a function of lowering the glass melting temperature by lowering the viscosity of the glass and improving the solubility of the glass. However, the raw materials are generally expensive, and if they are contained in a large amount, the amount of evaporation from the molten glass also increases, so that it is not preferable to contain a large amount from the viewpoint of environmental protection. A preferable range of the content of B ₂ O ₃ is 1 to 8%, more preferably 2 to 7%, and most preferably 3 to 6.5%.

  MgO and CaO are both components that improve solubility.

An increase in the content of MgO is not preferable because diopsite (Di) (CaO.MgO.2SiO ₂ ) is likely to precipitate and the liquidus temperature rises. The preferable range of the content of MgO is 0 to 4%, more preferably 0 to 3%, and most preferably 0.1 to 3%.

When there is little content of CaO, the viscosity of a molten glass will become high and a meltability and spinnability will worsen. On the other hand, an increase in the content of CaO is not preferable because wollastonite (Wo) (CaO.SiO ₂ ) is likely to precipitate. The preferable range of the content of CaO is 16 to 25%, more preferably 20 to 25%, and most preferably 20 to 24%.

SrO and BaO are components that contribute to the improvement of the solubility and resistance to devitrification. Further, SrO and BaO can be partially substituted with MgO and CaO to reduce the content of these components, so that diopsite (Di) (CaO · MgO · 2SiO ₂ ) and wollastonite (Wo ) The precipitation temperature of (CaO.SiO ₂ ) can be lowered. As a result, devitrification hardly occurs during spinning, and productivity can be improved.

  An increase in SrO is not preferable because the raw material cost increases. The preferable range of the SrO content is 0.1 to 1.8%, more preferably 0.1 to 1.6%, still more preferably 0.1 to 1.4%, and most preferably 0.1 to 1%. It is.

  An increase in BaO is not preferable because the raw material cost increases. The preferable range of the BaO component is 0.1 to 1.8%, more preferably 0.1 to 1.5%, and most preferably 0.2 to 1%.

  When the total content of the alkaline earth metal oxides (MgO, CaO, SrO, BaO) is small, the viscosity of the molten glass increases, and the meltability and spinnability deteriorate. On the other hand, when there is much total amount of these components, devitrification will deteriorate. The total content of the alkaline earth metal oxide is preferably 22 to 29%, particularly preferably 23 to 28%.

  Among alkaline earth metal oxides, SrO and BaO materials are relatively expensive. Therefore, in addition to the method of introducing strontium carbonate or barium carbonate as a raw material, it can be used for liquid crystal displays and the like within a usable range, and it is also possible to use silica-aluminum-borate glass cullet containing SrO or BaO as a raw material. is there.

Alkali metal oxides (Li ₂ O, Na ₂ O, K ₂ O) have a function of significantly improving glass solubility and glass fiber spinnability. However, when the amount of alkali metal oxide is excessive, when a composite material is used, the alkali metal component in the glass is eluted, which makes it difficult to maintain strength over time. The total content of alkali metal oxides is preferably 0 to 2%, particularly 0 to 1%, and more preferably 0.1 to 0.8%. If a high-purity raw material composition is adopted as the raw material, the composition can be made substantially free of alkali metal oxides. A content of 1% or more may be allowed.

The preferable ranges of the contents of Li ₂ O, Na ₂ O, and K ₂ O are all 0 to 1%.

P ₂ O ₅ is a component having an effect of suppressing the formation of fine crystal nuclei in the molten glass. In particular, the effect of lowering the crystal formation temperature of wollastonite (Wo) (CaO.SiO ₂ ) and diopsite (Di) (CaO.MgO.2SiO ₂ ) is remarkable. However, an increase in the content of P ₂ O ₅ is not preferable because the tendency of glass to devitrify becomes strong. The preferable range of the content of P ₂ O ₅ is 0 to 2%, more preferably 0 to 1%, and most preferably 0.1 to 1%.

Further, in addition to the _{above, TiO 2, ZrO 2, As} 2 O 3, SnO 2, ZnO, Sb 2 O 3, SO 3, Cl 2, H 2 O, He, Ar, Xr, H 2, Fe, Ni , W, Mo, Pt, Rh, Ag, Au, Cu, Hg, or Nb can be contained in an appropriate amount as necessary. In particular, O ₂ , CO ₂ , CO, SO ₃ , N ₂ , Cl ₂ , H ₂ O, He, Ne, Ar, Xr or H ₂ that are gas components may be contained from 0.01 ppm to 1000 ppm. .

  The glass fiber of the present invention may contain fine crystals as long as there is no problem with the characteristics of the glass fiber or the application.

  The glass fiber of the present invention is preferably made of glass having a molding temperature Tx of 1250 ° C. or lower and a liquidus temperature Ty of 1130 ° C. or lower. The physical factors for glass that are important for making a molten glass into a fiber in the melt-spinning process are the surface tension of the molten glass and the viscosity of the molten glass, but the surface tension of the molten glass depends on temperature. Is generally about 300 dyn / cm. For this reason, the viscosity is the most important for making molten glass into a monofilament. The present inventor has found that the liquid phase temperature Ty is 1130 ° C. or less, particularly 1100 ° C. or less, more preferably 1080 ° C. It has been found that the molding temperature Tx is 1250 ° C. or lower, particularly 1230 ° C. or lower, more preferably 1200 ° C. or lower.

  Further, if the temperature difference between the molding temperature Tx and the liquidus temperature Ty is 100 ° C. or more, particularly 110 ° C. or more, and further 120 ° C. or more, the molding condition can be widened, and the count is finer to thicker than that. It is preferable because even glass fibers can be accommodated. By setting the liquidus temperature Ty to a temperature sufficiently lower than the molding temperature Tx, the temperature of the molten glass may fluctuate due to subtle variations in molding conditions at the molding temperature Tx, changes in the molding fiber diameter, etc. However, it is preferable because fine crystals are not precipitated in the molten glass and stable quality can be maintained.

  The above characteristics can be easily obtained by appropriately selecting the component ratio within the above composition range.

  Next, the method for producing the glass fiber of the present invention will be described by taking the direct melt method (DM method) as an example. The present invention is not limited to the following method. For example, a so-called indirect molding method (MM method: marble melt method) in which a glass fiber material molded into a marble shape is remelted and spun using a bushing apparatus is employed. You can also. This method is suitable for the production of small quantities of other varieties.

First, SiO ₂ 50-60%, Al ₂ O ₃ 10-16%, B ₂ O ₃ 0-8%, MgO 0-5%, CaO 16-30%, SrO 0.1 in terms of mass percentage in terms of oxide. _{~2%, BaO 0.1~2%, MgO} + CaO + SrO + BaO 22~30%, Na 2 O 0~2%, K 2 O 0~2%, Li 2 O + Na 2 O + K 2 O 0~2%, P 2 O 5 A glass raw material is prepared so that the glass contains 0 to 3%. The reason why the content of each component is as described above is as described above, and the description is omitted here.

  Subsequently, the prepared glass raw material batch is put into a glass melting furnace, vitrified, melted and homogenized. The melting temperature is preferably about 1400 to 1550 ° C.

  Subsequently, molten glass is spun and formed into glass fibers. More specifically, molten glass is supplied to the bushing device. Further, the glass is drawn into filaments from a number of bushing nozzles provided on the bottom surface of the bushing device, and is formed into glass fibers by focusing every predetermined number. By manufacturing using a bushing device, it is possible to continuously produce a large amount of glass fibers having a desired diameter, and it is possible to adjust the obtained glass fiber to have a variable diameter value within a predetermined range. is there.

  As for the bushing device, any device having desired heat resistance and sufficient strength, and having a predetermined opening for allowing molten glass to flow out to a part of the container. Can be used if there is. The structure of other parts of the bushing device, the presence or absence of an attached device, etc. are not questioned. Further, the overall size and shape of the bushing device, and further, the heating method, the number of holes, the hole size, the hole shape, the nozzle shape or the number of nozzles are not particularly limited. And what is comprised with what kind of material if it has predetermined intensity | strength can be used. Particularly preferred is one composed of a refractory metal containing platinum.

  In addition, about the heating method, the homogenization method, etc. of the molten glass which flows into a bushing apparatus, arbitrary methods can be employ | adopted and the flow rate of a molten glass, a raw material structure, etc. are not limited.

  Further, it is preferable to perform spinning while measuring and managing the molding temperature Tx of the molten glass by the bushing device in a range of ± 20 ° C. with respect to the target molding temperature. In this way, it is possible to finely adjust the bushing temperature for suppressing fluctuations in the diameter of the glass fiber to be molded, thereby making it possible to highly stabilize the molding viscosity of the glass fiber.

  The measurement management of the molding temperature Tx may be performed by measuring the temperature with any measuring means. For example, it may be a thermocouple or an optical method such as an optical pyrometer. The measured results can be monitored at any time by a program, etc., and by adding a heating / cooling system that can quickly respond to a sudden rise or fall in temperature, highly accurate management is possible. Become.

  Various treatment agents can be applied when the monofilament is focused. For example, sizing agent, binding agent, coupling agent, lubricant, antistatic agent, emulsifier, emulsion stabilizer, pH adjuster, antifoaming agent, colorant, antioxidant, hindering agent or stabilizer, etc. Or it can apply | coat and coat | cover an appropriate amount on the surface of the glass fiber which was converged combining arbitrary multiple types. Further, such a surface treatment agent or coating agent may be a starch type or a plastic type. For example, in the case of a sizing agent for FRP, acrylic, epoxy, urethane, polyester, vinyl acetate, vinyl acetate / ethylene copolymer, and the like can be used as appropriate.

  The glass fiber of the present invention thus formed is processed into chopped strands, yarns, rovings, etc. and used for various applications.

  The chopped strand is obtained by cutting glass fibers (strands) obtained by focusing glass monofilaments into a predetermined length. A yarn is a twisted strand. Roving is a combination of a plurality of strands wound in a cylindrical shape.

  About a chopped strand, the length dimension and fiber diameter are not limited. About the length dimension and fiber diameter of a fiber, what was adapted for a use can be selected. Further, any method for producing chopped strands can be adopted. An arbitrary method can be adopted as a cutting method. For example, an outer peripheral blade cutting device, an inner peripheral blade cutting device, a hammer mill, or the like can be used.

  Moreover, it does not restrict | limit especially about the usage form of a chopped strand. That is, chopped strands can be laminated or accumulated on a plane or three-dimensionally in a non-directional direction and integrated in a bulk shape with a specific binder.

  As for the yarn, the size and direction of the twist are not particularly limited.

  Moreover, about roving, it is not limited about the diameter of the wound-up fiber and the number of wires arranged.

  In addition to the above, the glass fiber of the present invention can also be used in the form of LFTP, continuous strand mat, bonded mat, cloth, tape, braided fabric, milled fiber, or the like. Moreover, it can also be set as the prepreg impregnated with resin. And for usage and molding methods that apply glass fiber, spray-up, hand lay-up, filament winding, injection molding, centrifugal molding, roller molding, or BMC using match die, SMC method, etc. Can do.

  Further, the glass fiber composition of the present invention is not limited to use as the above-described long fiber, and can be formed into a short fiber used for a heat insulating material, for example. In this case, it may be formed by a fiberizing device called a spinner instead of using a bushing device.

  The glass fiber of the present invention can be combined with an organic medium, concrete or mortar.

  Here, the organic medium is typified by an organic resin such as a thermoplastic resin or a thermosetting resin. Concrete is a mixture of cement, sand, gravel and water, and mortar is a mixture of cement, sand and water.

  As for the type of organic medium, it is possible to use one or more types of optimal resins as appropriate depending on the application, and other structural reinforcing materials such as carbon fibers, ceramic fibers, bead materials, etc. may be used in combination. it can.

  Further, the mixing ratio of various components constituting the concrete or mortar and the type of cement are not particularly limited. Fly ash etc. can also be added.

  Specifically, the glass fiber composite material of the present invention can be used in the following applications. For example, in applications related to electronic equipment, printed wiring boards, insulating boards, terminal boards, IC boards, electronic equipment housing materials, gear tape reels, various storage cases, optical parts packages, electronic parts packages, switch boxes, insulation supports For vehicle-related applications, vehicle roofing materials (roof materials), window frame materials, car body fronts, car bodies, lamp houses, air spoilers, fender grills, tank trolleys, ventilators, water tanks, filth tanks, seats, There are nose cones, fender grills, curtains, filters, air conditioning ducts, muffler filters, dash panels, fan blades, radiator tires, timing belts, etc. For aircraft-related applications, engine covers, air ducts, seat frames, containers, curtains, interior materials , Service There are trays, tires, anti-vibration materials, timing belts, etc. For shipbuilding, land transportation and shipping related applications, motor boats, yachts, fishing boats, domes, buoys, marine containers, floaters, tanks, traffic lights, road signs, curved mirrors, containers, pallets , Guardrails, lighting lamp covers, spark protection sheets, etc., for agriculture-related applications, there are greenhouses, silo tanks, spray nozzles, struts, linings, soil conditioners, etc. For construction, civil engineering and building materials, bathtubs, baths Toilet unit, toilet tank, septic tank, water tank, interior panel, capsule, valve, knob, wall reinforcement, precast concrete board, flat plate, parallel plate, tent, shutter, exterior panel, sash, piping pipe, reservoir, pool, road , Side wall of structure, concrete formwork, tarpaulin, waterproof liner , Curing sheets, insect screens, etc. For industrial facilities, bug filters, sewer pipes, water purification equipment, anti-vibration concrete reinforcement (GRC), water tanks, belts, chemical tanks, reaction tanks, containers, fans , Ducts, corrosion-resistant linings, valves, refrigerators, trays, freezers, troughs, equipment parts, motor covers, insulation wires, transformer insulation, cable cords, work clothes, curtains, evaporation panels, equipment housings, etc. In, there are fishing rods, skis, archery, golf clubs, pools, canoes, surfboards, camera housings, helmets, shock protection armor, flower pots, display boards, etc.In daily goods related applications, tables, chairs, beds, benches, mannequins, There are trash cans and mobile phone protection materials.

  The glass fiber composition of the present invention can also be used as a spacer material. For example, in a liquid crystal display device used as a display device for a liquid crystal television or a personal computer, it can be used as a liquid crystal spacer used to maintain a distance between two substrate glasses. In this case, the monofilament is not focused but used alone.

  Furthermore, the glass fiber of the present invention can be recycled. That is, an article containing the glass fiber of the present invention may be subjected to a remelting step to be shaped into a fiber shape or various shapes other than a fiber such as a spherical shape or a granular shape and used for other purposes. For example, it can be used as a soil additive, a concrete additive, an aggregate, an asphalt additive, or the like.

Below, the composition for glass fibers and glass fiber of this invention are demonstrated concretely based on an Example.
[Example 1]
Table 1 shows Examples (Sample Nos. 1 to 10) and Comparative Examples (Sample No. 11) of the present invention.

  Sample No. Each glass sample of 1-11 was prepared in the following procedures, and used for each evaluation.

  First, a glass batch raw material obtained by weighing and mixing a predetermined amount of glass raw material so as to have each glass composition is put into a platinum rhodium crucible, and is heated at 1500 ° C. for 5 hours in an air atmosphere in an indirect heating type electric furnace. Was heated and melted. In order to obtain a homogeneous molten glass, the molten glass was stirred using a heat-resistant stirrer during heating and melting.

  Thereafter, the molten glass in a homogeneous state was poured out into a carbon mold, cast into a predetermined shape, and slowly cooled to obtain a final glass molded body for measurement.

  The physical characteristics of each glass composition of the examples shown in Table 1 were measured by the following procedure.

Regarding the molding temperature Tx corresponding to a viscosity value of 10 ³ dPa · s of the molten glass, each glass molded body was put into an alumina crucible, reheated and heated to a molten state, and then a platinum ball pulling method. It was calculated by interpolation of viscosity curves obtained by multiple measurements of each viscosity value measured based on.

  Also, for the liquidus temperature Ty, each glass molded body is cut into a predetermined shape and pulverized to a predetermined particle size, and the finely pulverized product is removed to a particle size range of 300 μm to 500 μm so as to have a predetermined surface area. Adjust and fill a platinum container with an appropriate bulk density, place it in an indirect heating type temperature gradient furnace set at a maximum temperature of 1250 ° C, and heat it in the atmosphere for 16 hours The operation was performed. Thereafter, the test specimen was taken out together with the platinum container, allowed to cool to room temperature, and then identified with a polarizing microscope and the specific operation of the liquidus temperature Ty, which is the deposition temperature, was performed.

  Further, ΔTxy indicating a temperature difference between the molding temperature Tx and the liquidus temperature Ty was calculated from the molding temperature Tx and the liquidus temperature Ty obtained by the above method.

  By the above test, test No. which is an example of the present invention. Since the samples 1 to 10 have a glass composition suitable for molding glass fibers as shown in Table 1, the molding temperature Tx is 1174 to 1194 ° C., the liquidus temperature Ty is 1030 to 1072 ° C., and ΔTxy is 110 to 110. It was 154 ° C., and it was confirmed that the material could be molded at a low temperature and was not easily devitrified during molding.

On the other hand, sample No. which is a comparative example. Since the glass composition of No. 11 does not contain SrO or BaO, the liquidus temperature Ty is as high as 1140 ° C., and the total amount of the alkaline earth metal oxide is as low as 22%, so that the molding temperature Tx is 1270 ° C. it was high.
[Example 2]
Next, glass fibers that can be realized by using the glass fiber composition of the present invention will be described.

  For example, sample no. After the glass fiber composition having the glass composition of 1 is melted, it is supplied to a bushing device having a platinum nozzle, and a monofilament having a diameter of 3 μm is pulled out from the bushing nozzle. A sizing agent is applied to the monofilament, and a plurality of bundles are bundled to form a strand.

  This bushing device is designed to operate a system capable of constantly monitoring the temperature of the molten glass in the bushing device corresponding to the bushing temperature by thermocouple measurement. The monitored temperature range is ± 20 ° C. with respect to the target molding temperature, and when the molding temperature deviates from the monitored temperature range, temperature adjustment is performed so as to correct it. For this reason, stable forming spinning is possible.

  As described above, when the composition of the present invention is used, yarn breakage hardly occurs even when continuously formed, so that glass fibers having a stable fiber diameter can be obtained.

As described above, the glass fiber to which the glass fiber composition of the present invention is applied, and the glass fiber-containing composite material exhibit excellent performance, and can be applied to all fields of industry. is there. Particularly useful in applications / fields where fine counts are required.

Claims (8)

_SiO 2 _50-60% by mass percentage of oxide _{equivalent, Al 2 O 3 10~16%,} B 2 O 3 1 ~ 7%, MgO 0.1 ~5%, CaO 16~30%, SrO 0. _{1~2%, BaO 0.1~2%, MgO} + CaO + SrO + BaO 22~30%, Na 2 O 0~2%, K 2 O 0~2%, Li 2 O + Na 2 O + K 2 O 0.1 ~2%, P glass fiber composition characterized in that it contains ₂ O _{5 0~3%.}   2. The glass fiber composition according to claim 1, wherein the molding temperature Tx is 1250 ° C. or less and the liquidus temperature Ty is 1130 ° C. or less.   The glass fiber composition according to claim 1 or 2, wherein a temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty is 100 ° C or more.   A glass fiber comprising the glass fiber composition according to any one of claims 1 to 3.   The glass fiber according to claim 4, wherein the glass fiber is in the form of chopped strand, yarn, or roving.   A glass fiber-containing composite material comprising the glass fiber according to claim 4 or 5 combined with an organic medium, concrete or mortar. _SiO 2 _50-60% by mass percentage of oxide _{equivalent, Al 2 O 3 10~16%,} B 2 O 3 1 ~ 7%, MgO 0.1 ~5%, CaO 16~30%, SrO 0. _{1~2%, BaO 0.1~2%, MgO} + CaO + SrO + BaO 22~30%, Na 2 O 0~2%, K 2 O 0~2%, Li 2 O + Na 2 O + K 2 O 0.1 ~2%, P _A glass raw material is prepared so as to be a glass containing ₂ O ₅ 0 to 3%, melted, then spun and formed into glass fiber.   The method for producing glass fibers according to claim 7, wherein spinning is performed while measuring and managing in a range of ± 20 ° C. with respect to a target molding temperature.