Abstract: The glass-fiber-yarn joined body 1 is provided with glass fiber yarns 2, 3, and a connection 5 in which a resin yarn 4 is wound around ends of both of the glass fiber yarns 2, 3, the ends being superimposed with each other. The connection 5 has a width W1 of 20 to 40 mm. When a connection diameter R as a total of diameters of the respective glass fiber yarns 2, 3 and the thickness of the resin yarn 4 wound around the connection 5 is 500 to 5000 ?m and a mass of each of the glass fiber yarns 2, 3 is 200 to 6000 tex, a value of a ratio of mass of each of the glass fiber yarns 2, 3 relative to the connection diameter R is in the range of 0.32 to 2.00.

Abstract: The glass-fiber-yarn joined body 1 is provided with glass fiber yarns 2, 3, and a connection 5 in which a resin yarn 4 is wound around ends of both of the glass fiber yarns 2, 3, the ends being superimposed with each other. The connection 5 has a width W1 of 20 to 40 mm. When a connection diameter R as a total of diameters of the respective glass fiber yarns 2, 3 and the thickness of the resin yarn 4 wound around the connection 5 is 500 to 5000 ?m and a mass of each of the glass fiber yarns 2, 3 is 200 to 6000 tex, a value of a ratio of mass of each of the glass fiber yarns 2, 3 relative to the connection diameter R is in the range of 0.32 to 2.00.

Abstract: Provided is a glass fiber-reinforced resin molded article having excellent mechanical strength, heat resistance, long-term durability, and molding processability. This glass fiber-reinforced resin molded article is characterized in that glass fibers contained in the glass fiber-reinforced resin molded article have a fiber diameter D (?m) in a range from 3.0 to 12.0 ?m; the glass fibers contained in the glass fiber-reinforced resin molded article have a number-average fiber length L (?m) in a range from 160 to 350 ?m; the glass fiber-reinforced resin molded article has a glass fiber volume fraction V (%) in a range from 3.0 to 50.0%; and D, L, and V satisfy formula (1): 300.0?D2×L/V?1000.0??(1).

Abstract: Provided is a method for producing glass fiber, capable of stably performing the spinning of glass fibers without mixing of red crystals in glass fibers. When glass fibers are formed by discharging, from a nozzle tip, a molten glass obtained by melting glass raw materials mixed so as to give a glass composition including, when melted, in relation to the total amount thereof, SiO2 in a range from 57.0 to 62.0% by mass, Al2O3 in a range from 15.0 to 20.0% by mass, MgO in a range from 7.5 to 12.0% by mass, and CaO in a range from 9.0 to 16.5% by mass, and having a total content of SiO2, Al2O3, MgO and CaO of 98.0% by mass or more, the glass composition includes B2O3, Li2O, or B2O3 and Li2O as an additive or additives capable of suppressing the generation of red crystals.

Abstract: Provided is a glass composition for glass fiber allowing spinning to be stably performed without mixing of red foreign substances into glass fibers. The glass composition for glass fiber includes, in relation to the total amount thereof, SiO2 in a content falling within a range from 57.0 to 60.0% by mass, Al2O3 in a content falling within a range from 17.5 to 20.0% by mass, MgO in a content falling within a range from 8.5 to 12.0% by mass, CaO in a content falling within a range from 10.0 to 13.0% by mass and B2O3 in a content falling within a range from 0.5 to 1.5% by mass, the total content of SiO2, Al2O3, MgO and CaO being 98.0% by mass or more.

Abstract: Provided is a glass composition for glass fiber allowing spinning to be stably performed without mixing of red foreign substances into glass fibers. The glass composition for glass fiber includes, in relation to the total amount thereof, SiO2 in a content falling within a range from 57.0 to 60.0% by mass, Al2O3 in a content falling within a range from 17.5 to 20.0% by mass, MgO in a content falling within a range from 8.5 to 12.0% by mass, CaO in a content falling within a range from 10.0 to 13.0% by mass and B2O3 in a content falling within a range from 0.5 to 1.5% by mass, the total content of SiO2, Al2O3, MgO and CaO being 98.0% by mass or more.