HK1181375B - Glass fiber - Google Patents

Description

Glass fiber

[ technical field ] A method for producing a semiconductor device

The invention relates to glass fibers, in particular to high-elasticity glass fibers.

[ Prior Art ] A method for producing a semiconductor device

Conventionally, SiO has been known as a glass for glass fibers having excellent strength and elastic modulus₂、Al₂O₃And MgO (S glass). However, from the viewpoint of the 1000 poise temperature and the liquidus temperature, the S glass is not necessarily easy to produce glass fibers. The 1000-poise temperature is a temperature at which the glass has a melt viscosity of 1000 poise, and the liquidus temperature is a temperature at which crystallization first occurs when the temperature of the molten glass is lowered. In general, when the glass is spun so that the melt viscosity of the glass is around 1000 poise, the glass fiber can be efficiently produced, and therefore the spinning is usually performed in a temperature range (working temperature range) between the 1000 poise temperature and the liquidus temperature. The working temperature range of S glass is narrow, namely molten glassCrystallization (devitrification) is likely to occur even under the influence of a slight temperature decrease. Therefore, in order to stably perform spinning, it is necessary to control the spinning conditions with good accuracy in the manufacturing step of the glass fiber.

As for the improved products of S glass, SiO-containing glass is known₂、Al₂O₃And glass compositions of MgO and CaO (patent documents 1 and 2). Patent document 1 discloses a glass composition in which fiberization is facilitated with a decrease in liquidus temperature. Patent document 2 discloses that a difference between a temperature (fiberization temperature) corresponding to a viscosity at a temperature of about 1000 poise and a maximum temperature (liquidus line) at which a balance exists between the liquid glass and its primary crystal phase is large.

Documents of the prior art

Patent document

Patent document 1: japanese examined patent publication No. 62-001337

Patent document 2: japanese Kokai publication No. 2009-514773

[ summary of the invention ]

[ problems to be solved by the invention ]

However, as a result of studies by the present inventors, the glass composition of the above document has a somewhat wide working temperature range, but the 1000 poise temperature and the liquidus temperature are high in some cases, and it is not always easy to produce glass fibers. In addition, the elastic modulus of the obtained glass fiber tends to be insufficient.

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a glass fiber which is easy to manufacture and has a sufficient elastic modulus.

[ means for solving problems ]

In order to achieve the above object, the glass fiber of the present invention comprises: SiO based on the total weight₂57.0 to 63.0 wt.% of Al₂O₃19.0 to 23.0 wt%, MgO 10.0 to 15.0 wt%, CaO 4.0 to 11.0 wt%, and SiO₂、Al₂O₃And a total content of MgO and CaO of 99.5 wt% or more. By having such a composition, the 1000 poise temperature and the liquidus temperature can be lowered, and therefore, the glass composition can be easily produced. And also has a sufficient modulus of elasticity.

In the composition of the above glass fiber, SiO₂Content and Al₂O₃The total content of the components is preferably 77.0 to 85.0 wt%. If the total content is 85.0 wt% or less, the 1000 poise temperature and the liquidus temperature can be lowered, and the glass composition can be easily produced. On the other hand, if the total content is 77.0 wt% or more, the devitrification phenomenon of crystal precipitation in the glass is hard to occur, and therefore, spinning becomes easy at the time of production thereof.

The glass fiber preferably has a composition of SiO₂Content of Al₂O₃The content is 2.7-3.2 by weight ratio. Within such a range, the glass fiber will have a wide working temperature range at the time of its production and will also have a sufficient modulus of elasticity.

In the composition of the glass fiber, the total content of the MgO content and the CaO content is preferably 16.0 wt% or more. In this case, the glass composition from which the glass fiber is used has a low 1000 poise temperature and a low liquidus temperature, and the viscosity of the molten glass is reduced, so that the glass composition is easily melted, and thus the glass composition can be more easily produced.

In the composition of the glass fiber, the weight ratio of the MgO content/CaO content is preferably 0.8 to 2.0. When the weight ratio is 2.0 or less, the liquidus temperature is lowered, and therefore, the working temperature range during production may be widened. On the other hand, if the weight ratio is 0.8 or more, the glass fiber will have a sufficient elastic modulus.

The present invention also provides a glass fiber having a composition satisfying the following conditions in which (a) SiO₂content/(SiO)₂Content + MgO content + CaO content). times.100, (b) MgO content/(SiO)₂Content + MgO content + CaO content). times.100, and (c) CaO content/(SiO)₂In 3-component phase diagrams represented by ((a), (b), (c)) with the content + MgO content + CaO content) × 100 as coordinates, SiO in the constituent components of the glass fiber₂The 3 components of MgO and CaO are in the range enclosed by the following coordinate points: (a ═ 81.0, (b ═ 19.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 29.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 15.0, (c) ═ 14.0), (a ═ 81.0, (b) ═ 8.0, and (c) ═ 11.0).

The present inventors have found that the devitrification rate can be suppressed by causing crystals (devitrification initial phase) formed first when the glass devitrifies to be cordierite crystals or mixed crystals of cordierite and anorthite. Especially in Al₂O₃When the amount is set to about 20 wt%, the devitrification initial phase is cordierite crystal or mixed crystal of cordierite and anorthite by satisfying the conditions of the 3-component phase diagram. Therefore, even when the working temperature range in the production of the glass fiber having such a composition cannot be sufficiently widened, the glass fiber is not devitrified, is easy to produce, and has a sufficient elastic modulus.

[ Effect of the invention ]

According to the present invention, by having a specific composition, a glass fiber having a sufficient elastic modulus, which is easy to manufacture, can be provided.

Drawings

FIG. 1 shows SiO of a glass fiber₂A composition diagram of 3 components of MgO and CaO.

FIG. 2 shows a method of manufacturing glass fibersAl₂O₃SiO in the case of a content fixed at 20% by weight₂And 3 components of MgO and CaO.

Detailed Description

The composition of the glass fiber of the present embodiment is characterized by containing SiO₂、Al₂O₃MgO and CaO, and the contents of the respective components are within the following ranges. Further, the content is based on the total weight of the glass fiber composition.

(1)SiO₂: 57.0 to 63.0% by weight

(2)Al₂O₃: 19.0 to 23.0% by weight

(3) MgO: 10.0 to 15.0% by weight

(4) CaO: 4.0 to 11.0% by weight

(5) The total of the above (1) to (4): 99.5 wt% or more

The glass fiber of the present embodiment has the above composition, and therefore can sufficiently widen the operating temperature range in the production from the glass composition, and can have an elastic modulus equivalent to that of S glass. Specifically, the 1000 poise temperature is 1385 ℃ or less (typically 1350 ℃ or less), the working temperature range is sufficiently secured (typically 40 ℃ or more), and glass fibers having a high elastic modulus of about 95GPa or more (typically 97 to 98GPa) can be efficiently obtained.

If SiO₂When the content is 57.0 wt% or more based on the total weight of the glass fiber composition, the mechanical strength of the glass fiber can be improved and the chemical properties are stable. On the other hand, when the amount is 63.0% by weight or less, the 1000 poise temperature and the liquidus temperature are lowered, and therefore, the glass fiber can be easily produced. In particular, SiO is used to make the 1000 poise temperature below 1350 ℃₂The content is preferably 57.5 to 62.0 weight percent based on the total weight of the glass fiber composition%, more preferably 58.0 to 61.0% by weight.

In Al₂O₃When the content is 19.0 wt% or more based on the total weight of the glass fiber composition, the elastic modulus can be improved. On the other hand, in the case of 23.0 wt% or less, the liquidus temperature is lowered, so that the working temperature range can be widened. Al (Al)₂O₃The content is preferably 19.5 to 22.0 wt%, more preferably 20.0 to 21.0 wt%, based on the total weight of the glass fiber composition.

When the content of MgO is 10.0 wt% or more based on the total weight of the glass fiber composition, the elastic modulus of the glass fiber can be improved. On the other hand, in the case of 15.0 wt% or less, the liquidus temperature is lowered, so that the working temperature range is widened. The MgO content is preferably 11.0 to 14.0 wt%, more preferably 11.5 to 13.0 wt%, based on the total weight of the glass fiber composition.

When the content of CaO is 4.0 to 11.0 wt% based on the total weight of the glass fiber composition, the glass fiber can be easily produced. That is, when the CaO content is 4.0 wt% or more based on the total weight of the glass fiber composition, the liquidus temperature is lowered, and thus the working temperature range is widened. On the other hand, in the case of 11.0 wt% or less, the 1000 poise temperature and the liquidus temperature can be lowered. In addition, since the liquid phase temperature of the glass composition may be increased when the CaO content is 11.0 wt% or more, the CaO content is preferably 5.5 to 10.5 wt%, more preferably 7.0 to 10.0 wt%, based on the total weight of the glass fiber composition.

In addition, since in SiO₂、Al₂O₃When the total content of MgO and CaO is less than 99.5 wt% based on the total weight of the glass fiber composition, the content of other impurity components becomes relatively large, and therefore, the working temperature range in the production of glass fibers or the elastic modulus of the obtained glass fibers cannot be secured. Therefore, the total content is preferably 99.7 wt% or more, more preferably 99.8 wt% or more, based on the total weight of the glass fiber composition。

In the composition of the glass fibers, SiO₂The contents (defined as A) and Al₂O₃The total content (A + B) of the content (defined as B) is preferably 77.0 to 85.0 wt%, more preferably 78.0 to 82.0 wt%. When a + B is 85.0 wt% or less, the melting temperature of the glass can be sufficiently lowered, and spinning becomes easy. Further, when a + B is 77.0 wt% or more, devitrification due to crystal precipitation in the glass hardly occurs, and therefore, spinning is facilitated in the production of glass fibers. Further, in order to set the 1000 poise temperature to 1350 ℃ or less, A + B is preferably 81.0 wt% or less. Further, in order to make the liquidus temperature 1300 ℃ or lower, A + B is preferably 80.0 wt% or lower.

In the composition of the glass fibers, SiO₂Content of Al₂O₃The content (defined as A/B) is preferably 2.7 to 3.2, more preferably 2.9 to 3.1, in terms of weight ratio. When A/B is 3.2 or less, a glass fiber having a high elastic modulus can be obtained. When the weight ratio is 2.7 or more, the liquid phase temperature can be lowered and the devitrification phenomenon can be suppressed.

In the composition of the glass fiber, the total content (C + D) of the MgO content (defined as C) and the CaO content (defined as D) is preferably 16.0 wt% or more, and when the C + D is 16.0 wt% or more, the 1000 poise temperature and the liquidus temperature can be lowered, and the glass composition can be easily melted and the viscosity can be reduced, so that the production of the glass fiber can be facilitated. Therefore, (C + D) is preferably 18.0 wt% or more.

In the composition of the glass fiber, the weight ratio of MgO content/CaO content (defined as C/D) is preferably 0.8 to 2.0, and more preferably 1.0 to 1.8. When the C/D is 2.0 or less, the liquid phase temperature is lowered, so that the working temperature range can be widened, and for example, the working temperature range can be secured to 40 ℃ or more. On the other hand, when the C/D is 0.8 or more, the elastic modulus of the glass fiber can be improved.

In addition, as described above, according to the findings of the present inventors of this new finding,containing SiO₂、Al₂O₃The devitrification speed of MgO and CaO glasses is affected by the type of devitrification initial phase. That is, in the case where the devitrification initial phase is a cordierite crystal or a mixed crystal of cordierite and anorthite, the crystal is less likely to be precipitated at the liquid phase temperature than in the case of other crystals. Therefore, when the molten glass having such a composition is spun, problems such as breakage and the like occurring in the production of glass fibers can be suppressed, and stable spinning can be performed.

From such a viewpoint, the glass fiber of the present embodiment preferably has a composition satisfying the following conditions: in the presence of (a) SiO₂content/(SiO)₂Content + MgO content + CaO content). times.100, (b) MgO content/(SiO)₂Content + MgO content + CaO content) × 100, (c) CaO content/(SiO)₂In a 3-component phase diagram represented by ((a), (b), and (c)) with the coordinate of content + MgO content + CaO content) × 100, SiO in the constituent components of the glass fiber₂The 3 components of MgO and CaO are in the range enclosed by the following coordinate points: (a ═ 81.0, (b ═ 19.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 29.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 15.0, (c) ═ 14.0), and ((a) ═ 81.0, (b) ═ 8.0, (c) ═ 11.0). Al (Al)₂O₃When the content is 19.0 to 23.0 wt%, particularly around 20 wt%, the glass composition for glass fibers having such a composition is advantageous in terms of production of glass fibers because the devitrification initial phase is cordierite crystal or mixed crystal of cordierite and anorthite.

In addition, in Al₂O₃Less than 19.0 wt%, in SiO₂In the 3-component phase diagram of MgO and CaO, devitrification initial phases may not be cordierite crystals or mixed crystals of cordierite and anorthite. Al for making devitrification primary phase cordierite crystal₂O₃The content is preferably 19.5% by weight or more based on the total weight.

The glass fiber of the present embodiment is prepared by mixing SiO₂MgO, CaO and Al₂O₃The content is determined as the above conditionMore preferably, the devitrification initial phase is a cordierite crystal or a mixed crystal of cordierite and anorthite. Here, a composition in which the devitrification initial phase is a cordierite crystal or a mixed crystal of cordierite and anorthite will be described below. FIG. 1 is a diagram showing SiO in a glass fiber₂A composition diagram of 3 components of MgO and CaO. In FIG. 1, the point X represents (SiO)₂The point where MgO, CaO) ═ 81.0 wt%, 19.0 wt%, 0.0 wt%, and the point Y indicates (SiO)₂MgO, CaO) ═ point (71.0 wt%, 29.0 wt%, 0.0 wt%). In addition, point Z represents (SiO)₂The point where MgO and CaO) ═ is (71.0 wt%, 15.0 wt%, 14.0 wt%), and the point W represents (SiO)₂MgO, CaO) ═ point (81.0 wt%, 8.0 wt%, 11.0 wt%). That is, the devitrification initial phase is a composition of cordierite crystal or mixed crystal of cordierite and anorthite, and satisfies the condition that the composition is within a tetragonal range surrounded by the points X, Y, Z and W.

The weight% of each component at the point X, Y, Z, W is SiO of the glass fiber₂The content of 3 components, MgO and CaO, taken as a total of 100 wt%, is shown. Incidentally, the composition of the glass fiber is other than SiO₂MgO and CaO, and at least Al₂O₃Therefore, the contents of the respective components shown in fig. 1 are different from the actual contents.

For example, in the composition of the glass fibers, Al₂O₃In the case where the content is 20.0% by weight based on the total weight, in the actual glass fiber composition in point X, Y, Z, W, SiO is contained as each component₂The contents of MgO and CaO are the value obtained by multiplying the above values by 0.8. FIG. 2 shows the expression in Al₂O₃SiO in the case of 20.0 wt% based on the total weight₂And 3 components of MgO and CaO. Specifically, the composition of the glass fiber satisfies the conditions: based on the total weight of the glass fiber composition, Al is₂O₃The content was 20.0% by weight, SiO₂56.8 to 64.8 wt%, 6.4 to 23.2 wt% MgO, and 0.0 to 11.2 wt% CaO% of the total weight of the composition, and is within a region enclosed by points X, Y, Z, W and V. In addition, the region of the above-mentioned 3-component composition in this composition diagram follows Al₂O₃The content varies.

The composition of the glass fiber of the present embodiment substantially contains SiO₂MgO, CaO and Al₂O₃And has the above-mentioned characteristic composition, but may contain other components, for example, the raw materials of the respective components are already contained or are inevitably mixed in, etc. As other components, Na may be mentioned₂Alkali metal oxides such as O and Fe₂O₃、Na₂O、TiO₂、ZrO₂、MoO₂、Cr₂O₃And the like. The total content of these other components may be less than 0.5% by weight, preferably less than 0.3% by weight, and more preferably less than 0.2% by weight, based on the total weight.

The glass fiber of the present embodiment may contain Fe, for example, to finely adjust the glass composition in order to improve both the mechanical strength and the spinnability₂O₃The content of the alkali metal oxide is preferably 0.4% by weight or less, more preferably 0.01% by weight or more and less than 0.3% by weight. In addition, in this case, Fe₂O₃The content is preferably 0.01 wt% or more and less than 0.3 wt%, more preferably 0.03 wt% or more and less than 0.2 wt%.

The glass fibers described above may be made from glass compositions. The glass fiber may be in any form of a glass fiber monofilament, a glass fiber bundle composed of a plurality of glass fiber monofilaments, or a glass fiber yarn obtained by twisting a glass fiber bundle. The filament diameter of the glass fiber can be set to 3 to 30 μm, for example, and the glass fiber bundle can be obtained by bundling 50 to 8000 filaments, for example. The glass fiber yarn can be produced by twisting the glass fiber bundle, for example, 13 times/25 mm or less. The glass fiber may be provided as a wound body wound around a core made of paper or plastic for about 10 to 200km, or may be provided as a glass fiber (chopped glass fiber bundle or the like) cut into about 1 inch. The glass fiber of the present embodiment can be provided as a glass fiber fabric, a woven fabric, a nonwoven fabric, a mat, a composite, a roving, a powder, or the like. The glass fiber of the present embodiment may be used alone, but 2 or more kinds of known commercially available glass fibers, carbon fibers, aramid fibers, ceramic fibers, and the like may be used in combination.

The glass fiber can be produced by a known method such as a remelting method or a direct melting method. In these known methods, a glass fiber is generally obtained by drawing a molten glass composition at a high speed through several hundreds to several thousands of platinum nozzles to fiberize the glass composition.

The cross-sectional shape of the glass fiber according to the present embodiment may not be all generally circular, but may be a flat cross-sectional fiber of an elliptical, oblong, or cocoon type, or a fiber having a special shape such as a star shape, a quadrangle shape, or a triangle shape. In particular, when the glass fiber is a flat cross-section fiber or a fiber having a special cross-section, it is necessary to perform spinning at a high viscosity. Therefore, if the composition is such that the devitrification primary phase of the glass becomes cordierite crystal or mixed crystal of cordierite and anorthite, the crystal of the molten glass is hardly precipitated even at a low temperature, which is a high viscosity, and glass fiber can be produced at a high temperature.

That is, in the case where the glass fiber is a flat cross-section fiber or a special-shaped cross-section fiber, it is preferable to satisfy the following conditions (1) to (2) in order to facilitate production and to have a sufficient elastic modulus. In order to more stably spin glass fibers, the following condition (3) is preferably satisfied.

(1) The composition of the glass fiber is based on the total weight, SiO₂57.0 to 63.0 wt.% of Al₂O₃19.0 to 23.0 wt%, MgO 10.0 to 15.0 wt%, CaO 4.0 to 11.0 wt%,

(2)SiO₂、Al₂O₃the total content of MgO and CaO is 99.5 wt%In the above-mentioned manner,

(3) has a composition satisfying the following conditions: in the presence of (a) SiO₂content/(SiO)₂Content + MgO content + CaO content). times.100, (b) MgO content/(SiO)₂Content + MgO content + CaO content) × 100, (c) CaO content/(SiO)₂SiO in a 3-component phase diagram represented by ((a), (b), and (c)) with the content + MgO content + CaO content) × 100 as coordinates₂The 3 components of MgO and CaO are in the range enclosed by the following coordinate points: (a ═ 81.0, (b ═ 19.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 29.0, (c) ═ 0.0), (a ═ 71.0, (b) ═ 15.0, (c) ═ 14.0), and ((a) ═ 81.0, (b) ═ 8.0, (c) ═ 11.0).

In the case of a flat cross-section fiber or a special cross-section fiber, the reduced fiber diameter is preferably 3 to 30 μm, and more preferably 5 to 20 μm. In particular, in the case of a flat-section fiber, the aspect ratio is preferably 2 to 8, and more preferably 3 to 7. The reduced fiber diameter is the diameter of a fiber having a circular cross section and the same fiber cross section, and the aspect ratio is the ratio of the long side to the short side (long side/short side) of a rectangle having the smallest area and circumscribing the cross section of the glass fiber.

Then, the glass fiber obtained by the above method can be suitably used for various purposes. For example, the glass fiber reinforced material can be suitably used for FRP used as an industrial material or an automobile part material, glass fiber for FRTP, or a glass fiber reinforced material for a laminate for a printed wiring board of an electronic material.

Further, by using the glass fiber of the present embodiment for a reinforcing material (matrix resin), a glass fiber composite material can be produced. The method of manufacturing the glass fiber composite material varies depending on the matrix resin used. When a thermoplastic resin is used, a glass fiber composite material can be produced by a technique such as a stampable sheet molding method, an injection molding method, or an impregnation method. As the thermoplastic resin, for example, polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile/butadiene/styrene (ABS) resin, methacrylic resin, vinyl chloride resin, polyamide resin, polyacetal resin, polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polycarbonate resin, polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, Liquid Crystal Polymer (LCP) resin, fluorine resin, polyether imide (PEI) resin, Polyarylate (PAR) resin, Polysulfone (PSF) resin, polyether sulfone (PES) resin, polyamide imide (PAI) resin, or the like can be used.

On the other hand, when a thermosetting resin such as an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a melamine resin, or a phenol resin is used as the matrix resin for the glass fiber composite material, a production method such as a hand lay-up method, a spray method, a Resin Transfer Molding (RTM) method, a sheet molding compound (SMS) method, a Bulk Molding Compound (BMC) method, an extrusion method, a filament winding method, or an injection method can be used.

In the glass fiber composite material, in addition to the matrix resin, cement, mortar, concrete, asphalt, metal, carbon, ceramics, natural rubber, synthetic rubber, and the like can be used as the reinforcing material.

The glass fiber composite material using glass fibers can be used as a material for various applications described below. For example, in the field of use in aircrafts, it is used for base materials, interior materials, vibration-proof materials, etc. for aircrafts, and in the field of use in vehicles, it is used for vibration-proof reinforcing materials, bumpers, engine fenders, roof materials, car bodies, tail fins, noise-damping filters, crash panels, radiators, timing belts, etc. Further, in the applications related to ships, the coating composition can be used for a motorboat, a sailing boat, a fish boat, etc., in the applications related to construction, civil engineering and building materials, the coating composition can be used for decorative walls, light-transmitting ceiling and lamp housings, surface coverings, insect-proof nets, roll screens, tent films, back lights, lighting billboards, flat panels and folded plates, concrete insect-proof reinforcements, outer wall reinforcements, coating film waterproofing materials, smoke-proof walls, non-flammable transparent partitions, projection screens, road reinforcements, bathtubs, toilet units, etc., and in the applications related to leisure sports, the coating composition can be used for fishing rods, tennis rackets, golf clubs, skis, helmets, etc. Further, the resin composition can be used for electronic equipment-related applications such as printed circuit boards, insulating boards, terminal boards, IC boards, electronic equipment casing materials, electronic component packaging materials, optical equipment casing materials, optical component packaging materials, insulating supports, and the like, can be used for industrial equipment-related applications such as windmill blades, glass filter bags, covering materials for non-combustible heat insulating materials, reinforcing materials for cemented grinding stones, aluminum filters, and the like, and can be used for agricultural-related applications such as plastic greenhouses, agricultural poles, and storage tanks. In addition, as the glass fiber composite material, a reinforcing material which is a known fiber-reinforced composite material can be used.

[ examples ]

Suitable examples of the present invention will be described in further detail below, but the present invention is not limited to these examples.

[ preparation of glass composition for glass fiber and evaluation thereof ]

Glass raw materials were blended so as to have the compositions shown in tables 1, 2 and 3, and the basic composition was SiO₂(A)、Al₂O₃(B) The glass composition having the composition of MgO (C) and CaO (D) was melt-spun to obtain glass fibers having a fiber diameter of 13 μm. The obtained glass fiber had a composition equivalent to that of the glass composition as a raw material. Then, for each glass fiber, the 1000 poise temperature, the liquidus temperature and the working temperature range at the time of production were obtained, and simultaneously, the devitrification resistance was evaluated, the crystallization of the devitrification initial phase was analyzed, and the elastic modulus of the finally obtained glass fiber was measured. The results obtained are disclosed in tables 1, 2 and 3 together with the composition. These properties were obtained by the following evaluation methods.

(1) Temperature of 1000 poise: using glasses of respective glass compositions melted in platinum crucibles, the viscosity was continuously measured with a rotary B-type viscometer while changing the melting temperature of the glass, and the temperature corresponding to the viscosity of 1000 poise was set as the 1000 poise temperature. The viscosity was measured based on JIS Z8803-1991.

(2) Liquid phase temperature: the glass pulverized material of each glass composition was placed in a platinum dish, and heated by a tubular electric furnace having a temperature gradient of 1000 ℃ to 1500 ℃. The temperature at which crystals precipitated was defined as the liquid phase temperature.

(3) The operating temperature range: calculated from (1000 poise temperature) - (liquidus temperature).

(4) Modulus of elasticity: the elastic modulus was measured by an ultrasonic method. The ultrasonic waves (longitudinal wave sound velocity, transverse wave sound velocity) transmitted through the glass gob were measured, and the elastic modulus was calculated from the values of the specific gravity, longitudinal wave sound velocity, and transverse wave sound velocity of the glass.

(5) Evaluation of resistance to devitrification: after melting each glass composition at a temperature of 1000 poise or more, it was left at a temperature 150 ℃ C. + -. 50 ℃ C lower than the liquidus temperature for 6 hours. Next, the state of crystallization observed on the surface and inside of the glass composition was observed and evaluated in 3 stages. A indicates that no crystal was precipitated. B indicates that crystals were deposited on a part of the surface. C indicates that crystal precipitation occurred on the surface and inside.

(6) Devitrified primary phase seed crystal: the crystal initial phase portion precipitated was pulverized using a sample whose liquid phase temperature was measured, and analyzed by an X-ray diffraction apparatus, and the seed crystal was identified. The crystal seeds of the devitrified primary phases in tables 1 to 3 are described below. In the table, when 2 or more seed crystals were present, it was confirmed that two seed crystals were present in combination.

And (3) COR: cordierite (Cordierite)

And (3) ANO: anorthite (anorthe)

PYR: pyroxene (Pyroxene)

MUL: mullite (Mullite)

TRI: tridymite (Tridymite)

SPI: spinel (Spinel)

FOR: forsterite (Forsterite)

CRI: cristobalite (Cristobalite)

CAS：CAS(Calcium·Alminium·Silicate)

In addition, samples 1 to 19 shown in Table 1 correspond to examples, and samples 20 to 44 shown in tables 2 and 3 correspond to comparative examples. Then, samples 36 to 39 in Table 3 correspond to the glass compositions of examples 2 to 5 disclosed in Japanese patent publication No. 62-001337. The samples 40 to 44 in Table 3 correspond to the glass compositions of examples 1, 4, 7, 14 and 15 disclosed in Japanese patent application laid-open No. 2009-514773.

Further, the molten glasses of the compositions of examples 5 and 9 were spun to obtain flat-section glass fibers having a fiber diameter of 15 μm and a flattening ratio of 4, and having an oblong cross-sectional shape. As a result, it was confirmed that both the samples were excellent in spinning workability.

[ Table 3]

As shown in tables 1 to 3, it was confirmed that in the samples 1 to 19 of the examples, both the 1000 poise temperature and the liquidus temperature were lowered, a wide working temperature range was obtained, and a high elastic modulus was obtained, as compared with the samples 20 to 44 of the comparative examples.

Claims (9)

1. Glass fiber characterized by: based on the total weight of the raw materials,

SiO₂57.0 to 60.2 wt.% of Al₂O₃19.0 to 23.0 wt%, MgO 10.0 to 15.0 wt%, CaO 5.5 to 11.0 wt%, and SiO₂、Al₂O₃A total content of MgO and CaO of 99.5 wt% or more, SiO₂Content of Al₂O₃The content is 2.7-3.2 by weight ratio, and the MgO content/CaO content is 0.8-2.0 by weight ratio.

2. The glass fiber of claim 1, having SiO₂Content of Al₂O₃The content is 2.7-3.1 in weight ratio.

3. The glass fiber of claim 1, having SiO₂Content and Al₂O₃The total content of the components is 77.0-85.0 wt%.

4. The glass fiber according to claim 1, which has a composition in which the total content of MgO and CaO is 16.0 wt% or more.

5. The glass fiber of claim 1, having the following composition:

further contains Fe₂O₃With alkali metal oxides, Fe₂O₃The total content of the content and the alkali metal oxide content is 0.4 wt% or less.

6. The glass fiber of claim 1, having a composition that satisfies the following condition:

in the presence of (a) SiO₂content/(SiO)₂Content + MgO content + CaO content). times.100, (b) MgO content/(SiO)₂Content + MgO content + CaO content). times.100, and (c) CaO content/(SiO)₂SiO in a 3-component phase diagram represented by ((a), (b), and (c)) with the content + MgO content + CaO content) × 100 as coordinates₂In the range surrounded by the following coordinate points, 3 components of MgO and CaO,

((a)＝81.0、(b)＝19.0、(c)＝0.0)、

((a)＝71.0、(b)＝29.0、(c)＝0.0)、

(a ═ 71.0, (b ═ 15.0, (c ═ 14.0), and

((a)＝81.0、(b)＝8.0、(c)＝11.0)。

7. the glass fiber according to claim 1, wherein the devitrification onset phase of the glass having the aforementioned composition is cordierite crystal or mixed crystal of cordierite and anorthite.

8. The glass fiber of claim 1, having the following composition:

further contains Fe₂O₃With alkali metal oxides, Fe₂O₃The total content of the content and the alkali metal oxide content is 0.01 to 0.4 wt%.

9. The glass fiber according to claim 1, which has a composition of MgO content/CaO content in a weight ratio of 1.0 to 2.0.