HK1199011B - Glass fibers and fiber-reinforced resin compact using same - Google Patents

Description

Glass fiber and fiber-reinforced resin molded article using same

Technical Field

The present invention relates to a glass fiber having a non-circular cross-sectional shape and a fiber-reinforced resin molded article using the same.

Background

Conventionally, glass fibers having a non-circular cross-sectional shape have been proposed (for example, see patent document 1). In the present application, a shape in which all portions of the circumference are equally spaced from the center point is a perfect circle, and a shape different from the perfect circle is defined as a non-circular shape. The non-circular shape includes, for example, a flat shape, a star shape, a cross shape, a polygon shape, a doughnut shape, and the like. In addition, the flat shape includes, for example, an oval shape, an oblong shape, a cocoon shape, and the like.

The glass fiber having a non-circular cross-sectional shape is mixed with a thermoplastic resin and subjected to melt injection molding to form a fiber-reinforced resin molded article, and the mechanical strength, dimensional accuracy, bending, and the like of the fiber-reinforced resin molded article can be improved. The reason why the mechanical strength of the fiber-reinforced resin molded article is improved is that the glass fiber having a non-circular cross-sectional shape has a larger contact area with the thermoplastic resin than the glass fiber having a perfect circle in cross-sectional shape. In addition, the reason why the dimensional accuracy, the warpage, and the like of the fiber-reinforced resin molded article are improved is that the orientation of the fiber-reinforced resin molded article in the plane direction is better and the fiber-reinforced resin molded article is easily oriented 2-fold in comparison with a fiber having a perfect circular cross-sectional shape when the fiber-reinforced resin molded article is formed from the fiber-reinforced resin molded article.

In general, the glass fiber having a non-circular cross-sectional shape is formed of E glass, but the glass fiber formed of E glass may not have sufficient strength and elastic modulus. Here, it is desirable to impart sufficient strength and modulus of elasticity to the glass fiber having a non-circular cross-sectional shape.

Glass fibers made of S glass are widely known as glass fibers having more excellent strength than glass fibers made of E glass. The glass fiber made of S glass contains 65 mass% of SiO2, 25 mass% of Al2O3, and 10.0 mass% of MgO, relative to the total amount of the glass fiber. However, the S glass melts a glass composition as a raw material thereof, and when a glass fiber is obtained as a molten glass by spinning from the molten glass, there is a problem that a difference between the 1000 poise temperature and the liquidus temperature of the molten glass is small.

The "1000 poise temperature" refers to a temperature at which the viscosity of the molten glass becomes 1000 poise, and the "liquidus temperature" refers to a temperature at which crystals are initially precipitated when the temperature of the molten glass is lowered. In general, the viscosity suitable for producing glass fibers is 1000 poise or less, and since stable spinning is possible as the temperature range (working temperature range) between 1000 poise temperature and the liquidus temperature is wider, the working temperature range is used as an index for ensuring spinnability.

If the difference between the 1000 poise temperature and the liquidus temperature of the molten glass is small, the molten glass is likely to be crystallized (devitrified) under the influence of only a temperature decrease in the process of being cooled after spinning to become glass fibers, and problems such as cutting of the glass fibers are likely to occur. Since the S glass has a relatively narrow working temperature range, when a glass composition as a raw material is melted as molten glass, it is difficult to stably spin glass fibers having a non-circular cross-sectional shape from the molten glass. "devitrification" refers to a phenomenon in which crystals precipitate when the temperature of the molten glass is lowered.

Here, it is proposed to improve the glass composition as a raw material of the S glass, which is a glass composition containing SiO2, Al2O3, MgO and CaO. As the glass composition, for example, a glass composition is known which can be easily spun at a relatively low temperature in an operating temperature range by lowering the viscosity by lowering the 1000 poise temperature (see patent document 2). As the glass composition, a glass composition having a large difference between 1000 poise temperature and liquidus temperature is known (see patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2006-45390

Patent document 2: japanese examined patent publication No. 62-001337

Patent document 3: japanese Kokai publication No. 2009-514773

Disclosure of Invention

Problems to be solved by the invention

However, the glass composition described in patent document 2 containing SiO2, Al2O3, MgO, and CaO tends to be easily devitrified when molten glass is formed by melting, and it is difficult to stably spin the glass. In addition, the glass composition described in patent document 3 is difficult to mass-produce because the 1000 poise temperature of the molten glass is high when the molten glass is obtained by melting. Therefore, it is difficult to obtain a glass fiber having a non-circular cross-sectional shape and having excellent strength and elastic modulus from the conventional glass composition.

In view of the above inconvenience, an object of the present invention is to provide a glass fiber having a non-circular cross-sectional shape and excellent strength and elastic modulus.

Another object of the present invention is to provide a fiber-reinforced resin molded article using the glass fiber having a non-circular cross-sectional shape.

Means for solving the problems

In order to achieve the above object, the glass fiber having a non-circular cross-sectional shape according to the present invention is a glass fiber obtained by melting a glass composition as a raw material of the glass fiber into molten glass and spinning the molten glass, and is characterized by comprising: the total amount of the composite material is 57.0 to 63.0 mass% of SiO2, 19.0 to 23.0 mass% of Al2O3, 10.0 to 15.0 mass% of MgO, and 5.5 to 11.0 mass% of CaO, and the ratio of the content of CaO to the content of MgO, MgO/CaO, is in the range of 0.8 to 2.0.

According to the present invention, a glass composition as a raw material of the glass fiber having the components is melted as a molten glass. Then, a glass fiber having a non-circular cross-sectional shape is obtained by spinning from the molten glass. Since the glass fiber having a non-circular cross-sectional shape of the present invention includes the above components, excellent strength and elastic modulus can be obtained.

When the content of the glass fiber based on the total amount of SiO2 is less than 57.0 mass%, sufficient mechanical strength as a glass fiber cannot be obtained, and when the content of the glass fiber based on the total amount of SiO2 exceeds 63.0 mass%, the 1000 poise temperature and the liquidus temperature of a molten glass obtained from a glass composition as a raw material thereof become high.

When the content of the glass fiber relative to the total amount of Al2O3 is less than 19.0 mass%, a sufficient modulus of elasticity cannot be obtained, and when the content of the glass fiber relative to the total amount of Al2O3 exceeds 23.0 mass%, the liquidus temperature of the molten glass obtained from the glass composition as a raw material thereof becomes high.

When the content of MgO in the glass fiber is less than 10.0 mass% relative to the total amount, a sufficient modulus of elasticity cannot be obtained, and when the content of MgO in the glass fiber exceeds 15.0 mass%, the liquidus temperature of the molten glass obtained from the glass composition as a raw material thereof becomes high.

When the content of the glass fiber with respect to the total amount of CaO is less than 5.5 mass%, the liquidus temperature of the glass composition becomes high, and when the content of the glass fiber with respect to the total amount of CaO exceeds 11.0 mass%, the 1000 poise temperature and the liquidus temperature of the molten glass obtained from the glass composition as the raw material thereof become high.

Further, when the ratio MgO/CaO of the glass fiber to the content of CaO, which is the content of MgO, is less than 0.8, a sufficient elastic modulus cannot be obtained, and when the ratio MgO/CaO of the glass fiber to the content of CaO, which is the content of MgO, exceeds 2.0, the liquidus temperature of the molten glass obtained from the glass composition as the raw material thereof becomes high.

In the glass fiber having a non-circular cross-sectional shape according to the present invention, the cross-sectional shape is, for example, a flat shape. The flat shape may be one selected from the group consisting of an oval shape, an oblong shape, and a cocoon shape.

Further, when a molten glass obtained from a glass composition as a raw material is spun, there is a problem that the glass fiber is easily devitrified and cut. However, in the present invention, since the glass fiber is provided with the components, the crystal that is initially precipitated when the temperature of the molten glass is lowered (initial stage of devitrification) is a single crystal of cordierite or a mixed crystal of cordierite and anorthite. Depending on the type of the initial stage of devitrification, the influence on the precipitation of crystals, the generation of bubbles, and the like can be known. However, in the initial devitrification stage of the molten glass, crystals are less likely to precipitate at the liquidus temperature, as compared with the case of crystals other than the above. Therefore, when the molten glass obtained by melting the glass composition as a raw material is spun, troubles such as cutting of glass fibers can be suppressed, and stable spinning can be performed.

In the present invention, the cross-sectional shape of the glass fiber can be made non-circular by setting the operating temperature range of the temperature range between the temperature at which the viscosity of the molten glass is 1000 poise and the liquidus temperature at which the crystallization is first precipitated, as the 1000 poise temperature, and by setting the viscosity (liquidus viscosity) of the molten glass corresponding to the liquidus temperature to 3000 poise or more when the temperature is lowered, to 50 ℃ or more.

The setting conditions of the temperature range of the spinning temperature are relatively strict for the glass fiber having a non-circular cross section as compared with the glass fiber having a circular cross section. In order to make the cross-sectional shape non-circular, it is necessary to spin at a high viscosity of 1000 poise or more. When the viscosity of the molten glass during spinning is less than 1000 poise, the glass fiber obtained by spinning has a circular cross section due to surface tension, and the cross section cannot be made to be non-circular. Therefore, in order to make the cross-sectional shape non-circular, it is generally necessary to spin at a high viscosity of 1000 or more. To satisfy this condition, it is necessary to make the viscosity of the liquid phase at least 3000 poise or more in order to secure the working temperature range of spinning. For stable spinning, the liquid phase viscosity is preferably 4000 poise or more, more preferably 5000 poise or more.

In addition, it is necessary to set the operating temperature range of the difference between 1000 poise temperature and the liquidus temperature to 50 ℃ or higher. If the working temperature range is narrow, there is a possibility that troubles in spinning such as cutting of the molten glass devitrified glass fibers may occur.

Accordingly, the glass fiber having a non-circular cross-sectional shape of the present invention is obtained by melting a glass composition as a glass fiber raw material as a molten glass and spinning the molten glass from the molten glass, and is characterized in that the operating temperature range of the difference between 1000 poise temperature and the liquidus temperature of the molten glass is 50 ℃ or more, and the liquidus viscosity of the molten glass corresponding to the viscosity of the liquidus temperature is 3000 poise or more.

The molten glass for melting a glass composition as a glass fiber raw material of the present invention has a temperature condition for spinning the glass fiber having a non-circular cross-sectional shape. Therefore, the glass fiber having a non-circular cross-sectional shape can be stably spun.

In the present invention, it is preferable that the strength of the glass fiber is 4.0GPa or more and the elastic modulus of the glass fiber is 85GPa or more. The glass fiber having a non-circular cross-sectional shape of the present invention can be suitably used for the purpose of constituting a fiber-reinforced resin molded product by setting the strength to 4.0GPa or more and the elastic modulus of the glass fiber to 85GPa or more.

The fiber-reinforced resin molded article of the present invention is formed by injection molding by mixing and melting the glass fiber having a non-circular cross-sectional shape with the thermoplastic resin. Since the fiber-reinforced resin molded article of the present invention contains the glass fiber having a non-circular cross-sectional shape, mechanical strength, dimensional accuracy, bending, and the like are improved, and excellent strength can be obtained.

Drawings

FIG. 1 is a graph showing the strength of a fiber-reinforced resin molded article in accordance with the type of glass fiber.

Detailed Description

Next, embodiments according to the present invention will be described in further detail.

The glass fiber having a noncircular cross-sectional shape according to the present embodiment is obtained by melting a glass composition as a glass fiber raw material as molten glass and spinning the molten glass. The glass fiber having a non-circular cross-sectional shape according to the present embodiment may have a flat cross-sectional shape, or may have various shapes such as a star shape, a cross shape, a polygonal shape, a trilobal shape, a quadralobal shape, an H shape, a U shape, a V shape, and a doughnut shape. Examples of the flat shape include an elliptical shape, an oval shape, a cocoon shape, and the like.

The glass fiber having a non-circular cross-sectional shape of the present embodiment has a composition in which the content of SiO2 is 57.0 to 63.0 mass%, the content of Al2O3 is 19.0 to 23.0 mass%, the content of MgO is 10.0 to 15.0 mass%, the content of CaO is 5.5 to 11.0 mass%, and the ratio of MgO/CaO with respect to the content of CaO is 0.8 to 2.0.

When the content of the glass fiber based on the total amount of SiO2 is less than 57.0 mass%, sufficient mechanical strength as a glass fiber cannot be obtained, and when the content of the glass fiber based on the total amount of SiO2 exceeds 63.0 mass%, the 1000 poise temperature and the liquidus temperature of a molten glass obtained from a glass composition as a raw material thereof become high. The content of the SiO2 is preferably within a range of 57.0 to 62.0 mass%, more preferably 57.0 to 61.0 mass%, relative to the total amount of the glass fibers, in order to keep the 1000 poise temperature of the composition of the molten glass obtained from the glass composition as a raw material of the glass fibers at 1350 ℃ or lower.

When the content of the glass fiber relative to the total amount of Al2O3 is less than 19.0 mass%, a sufficient modulus of elasticity cannot be obtained, and when the content of the glass fiber relative to the total amount of Al2O3 exceeds 23.0 mass%, the liquidus temperature of the molten glass obtained from the glass composition as a raw material thereof becomes high. In order to obtain an excellent modulus of elasticity in the glass fiber and to lower the liquidus temperature of the molten glass and to expand the operating temperature range, the content of Al2O3 is preferably in the range of 19.5 to 22.0 mass%, more preferably in the range of 20.0 to 21.0 mass%, relative to the total amount of the glass fiber.

The glass fiber content is in the range of 19.0 to 23.0 mass% relative to the total amount of Al2O3, and particularly, when the content is in the vicinity of 20.0 mass%, the devitrification in the molten glass obtained from the glass composition as a raw material thereof can be caused to be a single crystal of cordierite or a mixed crystal of cordierite and anorthite at the initial stage of the devitrification. When the content of Al2O3 is less than 19.0 mass% relative to the total amount of the glass fibers, the initial devitrification stage in the molten glass obtained from the glass composition as a raw material thereof cannot be caused to be a single crystal of cordierite or a mixed crystal of cordierite and anorthite. Here, in the glass fiber, the content of Al2O3 is preferably in a range of about 19.0 to 22.0 mass% relative to the total amount of the glass fiber, so that the initial stage of devitrification in the molten glass obtained from the glass composition as a raw material thereof is a single crystal of cordierite or a mixed crystal of cordierite and anorthite.

The weight ratio of the content of SiO2 to the content of Al2O3 is preferably 2.6 to 3.3. With this range, the glass fiber can have a wide range of operating temperatures during its production and can have a sufficient modulus of elasticity. Further, the weight ratio of the content of SiO 2/the content of Al2O3 is preferably 2.7 to 3.2. When the weight ratio of the content of SiO 2/the content of Al2O3 is 3.2 or less, a glass fiber having a high modulus of elasticity can be obtained. When the weight ratio is 2.7 or more, the liquidus temperature can be lowered and the devitrification phenomenon can be suppressed.

When the content of MgO in the glass fiber is less than 10.0 mass% relative to the total amount, a sufficient modulus of elasticity cannot be obtained, and when the content of MgO in the glass fiber exceeds 15.0 mass%, the liquidus temperature of the molten glass obtained from the glass composition as a raw material thereof becomes high. In order to obtain an excellent modulus of elasticity in the glass fiber and to lower the liquidus temperature of the molten glass and to expand the operating temperature range, the oil content of MgO is preferably in the range of 11.0 to 14.0 mass%, more preferably in the range of 11.5 to 13.0 mass%, relative to the total amount of the glass fiber.

When the content of the glass fibers with respect to the total amount of CaO is less than 5.5 mass%, the liquidus temperature of the molten glass obtained from the glass composition as the raw material thereof becomes high, and when the content of the glass fibers with respect to the total amount of CaO exceeds 11.0 mass%, the 1000 poise temperature and the liquidus temperature of the molten glass become high. In order to lower the 1000 poise temperature and liquidus temperature of the molten glass and to expand the operating temperature range, the content of CaO is preferably 6.0 to 10.5 mass%, more preferably 7.0 to 10.0 mass%, relative to the total amount of glass fibers.

Further, when the ratio of the content of MgO to the content of CaO in the glass fiber is less than 0.8, a sufficient elastic modulus cannot be obtained, and when the ratio of MgO to CaO exceeds 2.0, the liquidus temperature of the molten glass obtained from the glass composition as a raw material thereof becomes high. In order to obtain an excellent modulus of elasticity in the glass fiber and to lower the liquidus temperature of the molten glass and to expand the operating temperature range, the ratio MgO/CaO of the MgO content to the CaO content is preferably in the range of 1.0 to 1.8.

The glass fiber may contain SiO2, Al2O3, MgO, and CaO as essential components in the above-mentioned ranges, or may contain other components which are inevitably mixed due to factors such as raw materials contained in the respective components. Examples of the other components include alkali metal oxides such as Na2O, F2O3, TiO2, ZrO2, MoO3, Cr2O3, and the like. The content of the other component is preferably less than 1.0% by mass, more preferably less than 0.5% by mass, and still more preferably less than 0.2% by mass, based on the total amount of the glass fibers.

When the total content of SiO2, Al2O3, MgO, and CaO is 99.0 mass% or more and the content of other impurity components is relatively small, the glass fiber can obtain a sufficient elastic modulus. In addition, when glass fibers are produced from molten glass obtained from a glass composition as a raw material thereof, a sufficient working range temperature can be secured.

Further, the total content of SiO2, AL2O3, MgO, and CaO is 99.5 mass% or more, and more excellent elastic modulus can be obtained in the glass fiber. Further, in order to secure a sufficient working temperature range on the molten glass obtained from the glass composition as the raw material of the glass fiber, the total content of SiO2, AL2O3, MgO, and CaO is more preferably 99.8 mass% or more with respect to the total amount of the glass fiber.

The glass fiber has a glass composition as a raw material and a component equivalent to a molten glass obtained by melting the glass composition.

As the glass composition as a raw material of the glass fiber, cullet or a glass batch can be used. In addition, the molten glass can be obtained by a method of re-melting cullet or directly melting the glass batch. Specifically, the operating temperature range of the difference between the 1000 poise temperature and the liquidus temperature of the molten glass is 50 ℃ or more. Further, the viscosity (liquidus viscosity) of the molten glass corresponding to the liquidus temperature is 3000 poise or more, preferably 4000 poise or more, more preferably 5000 poise or more from the viewpoint of spinning stability.

The glass fiber having a non-circular cross-sectional shape can be produced from the molten glass by a known method. According to the known method, the molten glass spun yarn is drawn from several tens to several thousands of platinum alloy nozzles called bushings, and wound at high speed to obtain glass fibers.

Here, although the viscosity can be increased by lowering the temperature of the molten glass, when the target high viscosity region is lower than the liquidus temperature, troubles such as devitrified glass fiber breakage may occur. However, the molten glass of the present embodiment has the same composition as the glass fiber, has a wider operating temperature range, and has a small crystallization rate even when the initial stage of devitrification is a single crystal of cordierite or a mixed crystal of cordierite and anorthite. Here, the molten glass can be stably spun without devitrification, and a glass fiber having the non-circular cross-sectional shape can be obtained.

In order to prevent the molten glass from becoming round in the cross section of the spun glass fiber due to surface tension, it is necessary to spin the glass fiber having a non-circular cross-sectional shape at a high viscosity of 1000 poise or more. Since the fiber is spun in a high viscosity region of 1000 poise or more, it is necessary to lower the temperature of the molten glass, and the glass may be devitrified. Here, if the liquid phase viscosity is at least 3000 poise or more, glass fibers having a non-circular cross-sectional shape can be spun without devitrification of the glass when the molten glass is drawn from the nozzle.

Thus, it is necessary to more closely select the glass component and the spinning temperature range for spinning glass fibers having a non-circular cross-sectional shape than glass fibers having a circular cross-sectional shape.

The glass fiber having a non-circular cross-sectional shape spun as described above has a strength of 4.0GPa or more and an elastic modulus of 85GPa or more.

The glass fiber having a non-circular cross-sectional shape according to the present embodiment has excellent strength and elastic modulus as described above. Here, the glass fiber having a non-circular cross-sectional shape according to the present embodiment is, for example, melt-injection-molded by mixing with a thermoplastic resin, and thereby a fiber-reinforced resin molded product having excellent strength and elastic modulus while improving mechanical strength, dimensional accuracy, and bending can be obtained.

In order to use the glass fiber having a non-circular cross-sectional shape as a base material of the fiber-reinforced resin molded product, the fiber diameter is preferably in the range of 3 to 30 μm in terms of the cross-sectional area as a perfect circle. In order to use the glass fiber having a non-circular cross-sectional shape as a base material of the fiber-reinforced resin molded body, a glass deformation ratio represented by a ratio of a major axis to a minor axis is preferably in a range of 2 to 10 when measuring the major axis and the minor axis of the cross-sectional shape.

Examples of the thermoplastic resin include polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile/butadiene/styrene (ABS) resin, methacrylic resin, vinyl chloride resin, polyamide resin, polyacetal resin, polyethylene terephthalate (PET) resin, polyethylene terephthalate (PBT) resin, polycarbonate resin, polyphenylene sulfide (PPS) resin, polyether ether ketone (PEEK) resin, Liquid Crystal Polymer (LCP) resin, fluororesin, Polyetherimide (PEI) resin, Polyarylate (PAR) resin, Polysulfone (PSF) resin, Polyethersulfone (PES) resin, and polyamide-imide (PAI) resin.

In addition, a thermosetting resin may be used instead of the thermoplastic resin, and examples of the thermosetting resin include an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a melamine resin, a phenol resin, and the like. The thermoplastic resin or the thermosetting resin may be used alone, or may be a combination of 2 or more.

In addition, instead of injection molding, known molding methods such as press molding, infusion molding, hand lay-up, spraying, Resin Transfer Molding (RTM), Sheet Molding Compound (SMC), Bulk Molding Compound (BMC), pultrusion, and filament winding can be used.

In the molding method, the glass fiber having a non-circular cross-sectional shape of the present embodiment may be used alone, or one or more kinds of glass fibers having a perfect circular cross-sectional shape, which are the same component as the glass fiber having a non-circular cross-sectional shape of the present embodiment, known commercially available glass fibers, carbon fibers, organic fibers, ceramic fibers, and the like may be used in combination.

The glass fiber having a non-circular cross-sectional shape according to the present embodiment can be used as a glass fiber reinforced base material for various composite materials such as a glass fiber woven fabric, a cloth assembly, a woven fabric, a nonwoven fabric, a mat, a three-axis cloth assembly, a four-axis cloth assembly, a chopped strand, a roving, and a powder, which are used as a manufacturing material.

The fiber-reinforced resin molded product of the present embodiment can be suitably used for applications such as parts and members that require excellent mechanical strength and dimensional accuracy. Examples of the parts and components include vehicle exterior parts, vehicle interior parts, parts around a vehicle engine, electronic component cases, electronic components, and high-pressure tanks.

Examples of the vehicle exterior member include a door mirror, a member around a sunroof, and the like. Examples of the vehicle interior component and the components around the vehicle engine include a console box and a hood. Examples of the electronic device case include a cellular phone case, a computer case, a lens barrel of a digital camera, and a game machine case. In addition. The electronic component may be a connector.

Next, examples of the present invention and comparative examples are shown.

Examples

[ example 1]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO and the content of Fe2O3 were 60.2 mass%, 20.1 mass%, 10.1 mass%, 9.5 mass% and 0.1 mass%, respectively, to the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.9 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 1.1. The components of the glass composition are shown in Table 1.

Next, a pulverized glass having the same composition as the above glass composition is contained in a platinum boat, and heated in a tubular electric furnace having a temperature gradient of 1000 to 1500 ℃ to set the temperature at which crystallization starts as a liquidus temperature.

Next, the glass composition was melted in a platinum crucible, and while changing the temperature of the molten glass, the viscosity was continuously measured using a rotary B-type viscometer, and the corresponding temperature at 1000 poise was 1000 poise. The viscosity at the liquidus temperature is a liquid phase viscosity. Also, the viscosity was measured in accordance with JIS Z8803-1991. The 1000 poise temperature, liquidus temperature and liquidus viscosity are shown in Table 2.

Then, the glass composition is heated to the temperature of above 1000 poise temperature, melted, and then placed at 100 to 300 ℃ lower than the liquidus temperature for 6 hours. Next, the morphology of crystals found on the surface and inside of the glass composition was observed, and the devitrification resistance was evaluated in a, B, and C3 stages. A indicates that no crystal was precipitated, B indicates that a part of the crystal was precipitated on the surface, and C indicates that the crystal was precipitated on the surface and inside.

Next, the initial stage of the precipitated crystal was pulverized in a sample used for the measurement of the liquidus temperature, and analyzed by an X-ray diffraction apparatus to identify the crystal type at the initial stage of devitrification. The crystal types at the initial stages of the evaluation of devitrification resistance and devitrification are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle.

Next, a drawing test was performed using the monofilament of the glass fiber as a sample, and the strength and elastic modulus of the glass fiber were calculated.

Next, the filament of the glass fiber was used as a sample, the long diameter and the short diameter were measured on the cross section of the filament, and the ratio of the long diameter/the short diameter was used as the glass deformation ratio. The cross-sectional shape, glass deformation ratio, strength and modulus of elasticity of the glass fiber are shown in Table 2.

Next, a glass fiber bundle (strand) obtained by bundling glass fibers having the oblong cross-sectional shape was cut at a length of 3mm to produce chopped strands. Next, the obtained chopped strands were melt-kneaded with a polyamide resin (polyamide 66), and a fiber-reinforced resin pellet having a glass content of 30 mass% was produced by an extrusion molding method. Next, a plate-shaped fiber-reinforced resin molded article having a size of 80mm × 10mm × 4mm was produced by an injection molding method using the obtained fiber-reinforced resin pellets, and the strength of the fiber-reinforced resin molded article was calculated by a tensile test. The results are shown in Table 2.

[ example 2]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO and the content of Fe2O3 were 59.2 mass%, 20.1 mass%, 12.6 mass%, 8.0 mass% and 0.1 mass%, respectively, based on the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.9 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 1.6. The components of the glass composition are shown in Table 1.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1, except that the glass fiber having an oblong cross-sectional shape was used. The results are shown in Table 2.

Next, a fiber-reinforced resin molded article was produced in exactly the same manner as in example 1, except that the glass fiber having the oval cross-sectional shape obtained in this example was used, and the strength of the fiber-reinforced resin molded article was calculated by a tensile test. The results are shown in Table 2.

[ example 3 ]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO and the content of Fe2O3 were 58.2 mass%, 20.7 mass%, 12.0 mass%, 9.0 mass% and 0.1 mass%, respectively, based on the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.9 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 1.3. The components of the glass composition are shown in Table 1.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1 except that the glass fiber having the oval cross-sectional shape was used. The results are shown in Table 2.

Next, a fiber-reinforced resin molded article was produced in exactly the same manner as in example 1, except that the glass fiber having an oval cross-sectional shape obtained in this example was used, and the strength of the fiber-reinforced resin molded article was calculated by a tensile test. The results are shown in Table 2.

[ example 4 ]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO, the content of Fe2O3, and the content of Na2O were 61.4 mass%, 19.0 mass%, 12.9 mass%, 6.5 mass%, 0.1 mass%, and 0.1 mass%, respectively, relative to the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.8 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 2.0. The components of the glass composition are shown in Table 1.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1, except that the glass fiber having an oblong cross-sectional shape was used. The results are shown in Table 2.

[ example 5 ]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO and the content of Fe2O3 were 58.0 mass%, 21.9 mass%, 10.0 mass% and 0.1 mass%, respectively, based on the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.9 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 1.0. The components of the glass composition are shown in Table 1.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1, except that the glass fiber having an oblong cross-sectional shape was used. The results are shown in Table 2.

[ example 6 ]

In this example, first, glass raw materials were prepared so that the content of SiO2, the content of Al2O3, the content of MgO, the content of CaO and the content of Fe2O3 were 57.0 mass%, 20.0 mass%, 12.0 mass%, 10.9 mass% and 0.1 mass%, respectively, based on the total amount, to obtain a glass composition. The total content of SiO2, AL2O3, MgO, and CaO was 99.9 mass%, and the ratio MgO/CaO of the content of MgO to the content of CaO was 1.1. The components of the glass composition are shown in Table 1.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and the molten glass is spun to obtain glass fibers having a flat oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1, except that the glass fiber having an oblong cross-sectional shape was used. The results are shown in Table 2.

Next, a fiber-reinforced resin molded article was produced in exactly the same manner as in example 1, except that the glass fiber having the oval cross-sectional shape obtained in this example was used, and the strength of the fiber-reinforced resin molded article was calculated by a tensile test. The results are shown in Table 2.

[ comparative example 1]

In this comparative example, the liquidus temperature and liquidus viscosity were determined and the devitrification resistance was evaluated in the same manner as in example 1 except that so-called S glass (SiO 2; 64 to 66%, Al2O 3; 24 to 26%, MgO; 9 to 11%) was used to identify the crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition is melted as molten glass, and after the molten glass is spun, devitrification occurs in the molten glass and spinning cutting often occurs, so that a glass fiber having an oblong cross-sectional shape cannot be obtained. In order to prevent devitrification, the cross section of the glass fiber drawn from the platinum alloy nozzle cannot be prevented from being rounded due to surface tension after spinning at a high temperature of the molten glass, and the glass fiber has a substantially perfect circular cross section. Also, the obtained glass fiber had the same composition as the glass composition and the fiber diameter thereof was 15 μm.

Further, since the glass fibers obtained in the present comparative example had a substantially circular cross-sectional shape as described above, the glass deformation ratio, the strength and the modulus of elasticity of the glass fibers, and the strength of the fiber-reinforced resin molded article, which are expressed in "table 2, were not calculated.

[ comparative example 2]

In this comparative example, the liquidus temperature and liquidus viscosity were determined and the devitrification resistance was evaluated and the crystals at the initial stage of devitrification were identified in exactly the same manner as in example 1 except that so-called E glass (the content of SiO2 was 52.0 to 56.0 mass%, the content of Al2O3 was 12.0 to 16.0 mass%, the content of MgO was 0 to 6 mass%, the content of CaO was 16 to 25 mass%, the content of Na2O was 0 to 0.8 mass%, and the content of B2O3 was 5.0 to 10.0 mass%) was used. The results are shown in Table 2.

Then, in the same manner as in example 1 except that the glass composition obtained in this example was used, the liquidus temperature and liquidus viscosity were determined, and devitrification resistance was evaluated to identify crystals at the initial stage of devitrification. The results are shown in Table 2.

Next, the glass composition was melted as molten glass, and the molten glass was spun to obtain glass fibers having an oblong cross-sectional shape. The obtained glass fiber had the same composition as the above glass composition, and the fiber diameter was 15 μm when the cross-sectional area was converted to a perfect circle. Next, the strength, modulus of elasticity, and glass strain ratio of the glass fiber obtained in this example were calculated in the same manner as in example 1, except that the glass fiber having an oblong cross-sectional shape was used. The results are shown in Table 2.

Next, a fiber-reinforced resin molded article was produced in exactly the same manner as in example 1, except that the glass fiber having an oval cross-sectional shape obtained in this example was used, and the strength of the fiber-reinforced resin molded article was calculated by a tensile test. The results are shown in Table 2.

[ Table 1]

[ Table 2]

Devitrification resistance: a indicates that no crystal was precipitated, B indicates that a part of the crystal was precipitated on the surface, and C indicates that the crystal was precipitated on the surface and inside.

Initial stage of devitrification: cor … cordierite, ano … anorthite, mul … mullite, cri … cristobalite

The cross-sectional shape of the glass fiber can be made to be a non-circular cross-sectional shape "o". Here, a perfect circle is actually created, and the deformation ratio is measured. The glass of comparative example 1 is represented by "x", and since glass fibers having a non-circular cross-sectional shape could not be produced, strength and the like as properties of the glass fibers and strength of a molded article could not be measured.

In the table, "n.d." means that no test was performed, and "n" means that the shape of the obtained fiber could not be measured.

As is clear from table 2, the glass fibers having the oblong cross-sectional shapes of examples 1 to 6 have a strength of 4.0GPa or more and an elastic modulus of 85GPa or more, and have excellent strength and elastic modulus. Further, it is clear that the fiber-reinforced resin molded articles of examples 1 to 6 have excellent strength when produced using the glass fibers having the oval cross-sectional shape.

On the other hand, in comparative example 1, since CaO was not contained in the components of the glass fiber, the liquid phase viscosity was low, and the glass fiber having the oblong cross-sectional shape could not be obtained.

In comparative example 2, the glass fibers having the oblong cross-sectional shape had lower strength and lower modulus of elasticity than the glass fibers having the oblong cross-sectional shapes of examples 1 to 6 because the content of Al2O3 and MgO in the glass fiber components was less than the lower limit of the present invention. The fiber-reinforced resin molded article of comparative example 2 was also lower in strength than the fiber-reinforced resin molded articles of examples 1 to 6.

Further, the case of producing a fiber-reinforced resin molded article using the glass fiber of the present invention shows that the same level of traction strength as that of S glass, which is high-strength glass, can be achieved. Fig. 1 shows the results of measuring the tensile strength of molded articles produced by using the glass fibers (1, 2) of the present invention, E glass fibers (3, 4), and S glass fiber (5) in the same manner as described above.

Using the glass fibers manufactured from the glass component of example 1, the glass fibers manufactured from the round (fig. 1, 1), oval (fig. 1, 2), the E glass component, and the round (1, 5) glass fibers manufactured from the round (fig. 1, 3), oval (fig. 1, 4), S glass component as high-strength glass, fiber-reinforced resin molded bodies were manufactured in the same manner as in example 1, and a drawing test was performed.

In comparison with the glass fiber of the E glass component, an increase in strength of the molded article was observed in the case of using the glass fiber of the present invention. In the case of using the glass fiber of the present invention, even a glass fiber having a circular cross-sectional shape (fig. 1, 1) is clearly understood to have a slight increase in strength as compared with the case of using an oblong glass fiber (fig. 1, 4).

Further, when a molded body is produced by using the glass fiber having a non-circular cross-sectional shape of the glass component of the present invention (fig. 1, 2), the strength of the molded body can be achieved to the same extent as that of S glass which is high-strength glass (fig. 1, 5). By forming the non-circular cross-sectional shape, the contact area with the thermoplastic resin becomes wider than that of the glass fiber having a circular cross-sectional shape, and the strength at the time of producing a molded body is increased. Here, although glass fibers having a non-circular cross-sectional shape that is oblong are used, the contact area can be changed according to the cross-sectional shape of the glass fibers, and therefore, the surface area can be further adjusted, and the strength of the molded body can be increased.

By using the glass fiber having a non-circular cross-sectional shape of the present invention, it is possible to achieve high strength of a molded article. As a result, a thin molded article and/or a fine molded article can be manufactured with strength maintained, and therefore, the molded article can be reduced in weight.

Claims (7)

1. A glass fiber having a non-circular cross-sectional shape, which is obtained by melting a glass composition as a raw material of the glass fiber into molten glass and spinning the molten glass, characterized in that,

the glass fiber comprises the following components: relative to the total amount of SiO₂Has a content of 57.0 to 63.0 mass%, and Al₂O₃Has a content of 19.0 to 23.0 mass%, a content of MgO of 10.0 to 15.0 mass%, a content of CaO of 10.5 to 11.0 mass%, and contains an alkali metal oxide and Fe₂O₃、TiO₂、ZrO₂、MoO₃And Cr₂O₃The total content of the other components inevitably mixed in is less than 1.0 mass%, and the ratio of the content of MgO to the content of CaO is in the range of 0.8 to 2.0 MgO/CaO, and the glass fiber has a non-circular cross-sectional shape.

2. The glass fiber having a non-circular cross-sectional shape of claim 1, wherein the cross-sectional shape is a flat shape.

3. The glass fiber having a non-circular cross-sectional shape according to claim 2, wherein the flat shape is one selected from the group consisting of an oval shape, an oblong shape, a cocoon shape.

4. The glass fiber having a non-circular cross-sectional shape according to claim 1, wherein the crystal that is precipitated at the earliest when the temperature of the molten glass is lowered is a single crystal of cordierite or a mixed crystal of cordierite and anorthite.

5. The glass fiber having a non-circular cross-sectional shape according to claim 1, wherein an operating temperature range of the molten glass is 50 ℃ or more, and a liquidus viscosity of the molten glass is 3000 poise or more, the operating temperature range being a difference between 1000 poise temperature and a liquidus temperature, the liquidus viscosity being a viscosity corresponding to the liquidus temperature.

6. The glass fiber having a non-circular cross-sectional shape according to claim 1, wherein the strength of the glass fiber is 4.0GPa or more, and the modulus of elasticity of the glass fiber is 85GPa or more.

7. A fiber-reinforced resin molded article characterized in that,

the fiber-reinforced resin molded body is formed by mixing and melting glass fibers and a thermoplastic resin and injection molding,

the glass fiber comprises the following components: relative to the total amount of SiO₂Has a content of 57.0 to 63.0 mass%, and Al₂O₃Has a content of 19.0 to 23.0 mass%, a content of MgO of 10.0 to 15.0 mass%, a content of CaO of 10.5 to 11.0 mass%, and contains an alkali metal oxide and Fe₂O₃、TiO₂、ZrO₂、MoO₃And Cr₂O₃The total content of the other components inevitably mixed in is less than 1.0 mass%, and the ratio of the content of MgO to the content of CaO is in the range of 0.8 to 2.0 MgO/CaO, and the glass fiber has a non-circular cross-sectional shape.