CA2436506A1 - Process and device for formation of mineral wool and mineral wool products - Google Patents

Abstract

Glass fiber insulation products, and methods of manufacturing small diameter glass fibers with fewer stress-rising defects are provided. The insulation products of this invention can provide the same thermal resistance or R-valu e with reductions in fiber density of at least about 20% or more while achievi ng acceptable recovery of the nominal thickness following compression. The methods provided by this invention can produce fine diameter glass fibers wi th fewer defects through a combination of lower attenuating gas velocities and the use of spinners having more and smaller holes. A preferred method of the invention uses a device for internal centrifugation of mineral fibers including a centrifuge equipped with a peripheral bland perforated with orifices distributed in a plurality of annular zones (ZA) arranged on top of each other, assuming that the centrifufe is in centrifugation position. In accordance with the invention, the device also includes at least two annualr zones (ZA1, ZA2) whose number or orifices per unit of surface area (NS1, NS2 ) differs by a value greater than or equal to 5%, in particular greater than o r equal to 10%, and even 20%.

Claims (20)

1. A method of making a glass fiber insulation product, characterized by:
(a) providing at least one glass material;
(b) melting the glass material;
(c) disposing said molten glass material in a spinner (centrifuge) (1) having a plurality of spinner orifices (14);
(d) centrifuging the molten glass material through said plurality of spinner orifices (14) to form a multiplicity of glass streams (15);
(e) attenuating said glass streams (15) with a gas current adjacent the exterior of the spinner (1) to form glass fibers (10) having an average diameter of no greater than about 3.5 microns, said gas current being substantially provided by a burner (9) having a burner pressure of about 10-25 inches of water (250-635 mm CE) preferably less than 23 inches of water (580 mm CE), said burner having a pair burner lip portions (54, 56) separated by a width of at least 8 mm preferably between 8.1 and 8.5 mm ;
(f) combining the fibers (10) together with a resinous binder to form an insulation product having an ASTM C 686 parting strength of at least about 100 g/g, and exhibiting a substantial recovery of its nominal thickness following compression.

2. The method of claim 1 wherein said attenuating step (e) comprises an airflow of about 50,000-100,000 ft3/hr.

3. The method of one of the preceding claims wherein said attenuating step (e) comprises a gas flow rate of about 3,000-6,000 ft3/hr.

4. The method of one of the preceding claims wherein the spinner (centrifuge) (1 ) of step (c) and (d) has a peripheral band which is perforated with orifices (14) distributed in a plurality of annular zones (ZA) arranged on top of each other with the centrifuge in centrifugation position, and which includes at least two annular zones (ZA1, ZA2) whose number of orifices per unit of surface area (NS1, NS2) differs by a value greater than or equal to 5%, in particular greater than or equal to 10%, and even 20%, and in that the annular zone containing the greatest number of orifices per unit of surface area is located below the other annular zone, assuming that the centrifuge is in centrifugation position.

5. The method of claim 4 wherein the annular zone of the spinner (1)containing the greatest number of orifices per unit of surface area is located below another annular zone of the spinner (1) containing a lower average number of orifices per unit of surface area.

6. The method of claim 4 or claim 5 wherein the orifices (14) of each annular zone of the spinner (1) are grouped in rows, with-a diameter of orifice (d) substantially constant in each annular zone and decreasing from one annular zone to another, from the top to the bottom of the peripheral band of the centrifuge (7).

7. The method of claim 6 wherein the preceding rows are spaced from each other at a distance between 1 and 2 mm, in particular between 1.2 and 1.8 mm, preferably with a pitch from one row to the next of between 1 and 2 mm, for example between 1.2 and 1.6 mm.

8. The method of claims 4 to 7 wherein the diameter (d) of at least a part of the orifices (14) of the spinner centrifuge (1) is at most 1.5 or 1.2 mm, in particular between 1.1 and 0.5 mm, for example between 0.9 and 0.7 mm.

9. The method of claims 4 to 8 wherein the distance (D) between the centers of the closest orifices neighboring the same annular zone (ZA) of the spinner (1) is substantially constant over an entire annular zone and in that this distance (D) varies from one zone to another by at least 3%, or even at least 5%, and even 10% or more, and is decreasing from the top to the bottom, with in particular a distance D
between 0.8 and 3 mm, for example between 1 and 2 mm. and even between 1.4 and 1.8 mm.

10. The method of claims 1 to 9 wherein the centrifuge (1) presents an average diameter (DM) less than or equal to 800 mm, in particular by at least 200 mm.

11. The method of claims 1 to 10 wherein the high temperature gazeous drawing jet of step (e) is produced by an annular burner (9).

12. The method of claim 11 wherein the annular burner (9) is a tangential burner which includes a mechanism of giving the gaseous drawing jet a tangential component in relation to the external horizontal edge of the centrifuge.

13. An insulation product formed of fibers of a glass material, the fibers being produced by passing glass material in a molten state through orifices placed on the periphery of a spinner and being attenuated by gas currents surrounding the spinner, wherein said insulation product is characterized by:
(a) said glass fibers have an average diameter of no greater than about 3.0 microns;
(b) at least 50% of said fibers are less than 3.0 microns; and (c) said product has the following characteristics:
(i) an ASTM C 686 parting strength of at least about 100 g/g; and (ii) an ASTM C 167 product gram weight of about 40-210 g/ft2 preferably of about 70-100 9/ft; said insulation product exhibiting a substantial recovery of its nominal thickness following compression.

14. The insulation product of claim 13 wherein said insulation product has a thermal resistance value about equivalent to that for an insulation product of substantially similar external dimensions made from glass fibers having an average diameter of about 3.9 microns, but exhibiting at least a 12% lower gram weight than said insulation product made with fibers having an average diameter of about 3.9 microns.

15. The insulation product of claim 13 wherein said insulation product has a greater thermal resistance value than that for an insulation product made from glass fibers having an average diameter of about 3.9 microns, and exhibiting substantially similar external dimensions and substantially similar gram weight

16. The insulation product of claims 13 to 15 made with the method of any one of claims 1 to 12 and a burner inside pressure of less than about 23 inches water (585 mm CE).

17. An insulation batt or roll formed of fibers of a glass material, the fibers being produced by passing said glass material in a molten state through orifices placed on the periphery of a spinner and being attenuated by gas currents surrounding the spinner, said insulation batt being characterized by being composed of glass fibers having an average diameter of no greater than about 3 microns, said insulation batt having an ASTM C 167 thickness recovery and R-value thermal resistance rating of about equivalent to, or better than, that of an insulation product of substantially similar external dimensions made from glass fibers having an average diameter of about 3.9 microns.

18. The insulation batt or roll of claim 17 having an ASTM C 167 product gram weight of about 50-150 g/ft3.

19. The insulation batt or roll of claim 17 or 18 having a soft cotton-like feel.

20. An insulation batt or roll made with the method of any one of the claims 1-12.