Glass fiber production method

Patent metadata

Field	Value
Publication number	US-11040908-B2
Application number	US-201515752717-A
Country	US
Kind code	B2
Filing date	Aug 21, 2015
Priority date	Aug 21, 2015
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

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.

First claim

The invention claimed is:

1. A method for producing glass fiber, 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 comprising, when melted, in relation to the total amount thereof, SiO 2 in a range from 57.0 to 58.8% by mass, Al 2 O 3 in a range from 18.0 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 12.5% by mass, and having a total content of SiO 2 , Al 2 O 3 , MgO and CaO of 98.0% by mass or more, the glass composition comprises B 2 O 3 , or a combination of B 2 O 3 and Li 2 O, as an additive or additives capable of suppressing generation of red crystals,
wherein a ratio of the product between a content of the additive or additives capable of suppressing generation of red crystals (% by mass) and the content (% by mass) of CaO to the content (% by mass) of Al 2 O 3 is in a range from 0.25 to 1.00.

2. The method for producing glass fiber according to claim 1 , wherein the glass fibers each have a modified cross sectional shape in which a ratio (major axis/minor axis) of the major axis to the minor axis of the cross sectional shape falls within a range from 2.0 to 6.0.

3. The method for producing glass fiber according to claim 1 , wherein the glass fibers each have a modified cross sectional shape in which a fiber diameter defined as a diameter when a cross-sectional area is converted to a perfect circle, falls within a range from 10 to 30 μm.

4. The method for producing glass fiber according to claim 1 , wherein the glass fibers have perfect circular cross sections, and fiber diameters falling within a range of 3 μm or more to less than 10 μm.

5. The method for producing glass fiber according to claim 1 , wherein the glass raw materials mixed so as to give the glass composition are melted by using a melting furnace in which a portion in contact with the molten glass is formed of bricks containing chromium oxide.

6. The method for producing glass fiber according to claim 1 , wherein the glass composition comprises B 2 O 3 as the additive capable of suppressing the generation of red crystals, in a content of 0.5 to 1.5% by mass in relation to the total amount of the glass composition.

7. The method for producing glass fiber according to claim 1 , wherein the glass composition comprises B 2 O 3 and Li 2 O as the additives capable of suppressing the generation of red crystals, in a content of 0.5 to 1.5% by mass in relation to the total amount of the glass composition.

8. The method for producing glass fiber according to claim 1 , wherein in the glass composition, an 1000-poise temperature thereof is a temperature falling within a range from 1300 to 1370° C., a liquid phase temperature thereof is a temperature falling within a range from 1200 to 1270° C., and a working temperature range thereof is 50° C. or higher.

9. The method for producing glass fiber according to claim 1 , wherein the glass fibers each have a modified cross sectional shape in which a ratio (major axis/minor axis) of the major axis to the minor axis of the cross sectional shape falls within a range from 2.0 to 6.0, and a fiber diameter defined as a diameter when a cross-sectional area is converted to a perfect circle, falls within a range from 10 to 30 μm.

10. The method for producing glass fiber according to claim 1 , wherein the glass composition comprises CaO in a range of 10.3 to 12.5% by mass.

11. The method for producing glass fiber according to claim 1 , wherein the glass composition comprises MgO in a range of 8.8 to 12.0% by mass.

Assignees

• Nitto Boseki Co Ltd

Inventors

• Nonaka Takashi
• Hirayama Norio
• Minami Kazuaki
• Nukui Yosuke

Classifications

• C03B37/02

  by drawing or extruding, {e.g. direct drawing of molten glass from nozzles; Cooling fins therefor (C03B37/04 takes precedence; sizing of the fibres C03C25/00)} · CPC title

• C03C3/091

  containing aluminium · CPC title

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C13/00 Primary

  Fibre or filament compositions (manufacture of fibres or filaments C03B37/00) · CPC title

• C03B2203/02

  External structure or shape details · CPC title