Claims
- 1. A method of making a smooth, dimensionally stable mica-filled, glass fiber sheet having low porosity comprising:
- (a) preparing without prepulping an aqueous slurry having a pH below about 4.0 consisting essentially of glass fibers and, based on 100 parts by weight glass fibers, from 3 to 15 parts by weight organic fibers, 30 to 100 parts by weight mica flakes, and 5 to 20 parts by weight binder;
- (b) diluting the slurry to a consistency between about 0.01% and 0.05% by weight solids; and
- (c) depositing said slurry onto a moving screen, removing the excess of water to form a water laid sheet, and drying the sheet to set the binder.
- 2. The method in accordance with claim 1 in which the glass fibers have diameters in the range of 3-15 microns, an average length of 1/4 to 1/2 inch and are of a low alkali content, the mica flakes having size ranging from 20 to 100 mesh, and the organic fibers are of an average length between about 1/4 and 1/2 inch and deniers between about 1 and 6.
- 3. The method of claim 2 in which the organic fibers are polyester fibers and in which the binder is poly(vinyl alcohol) fibers which dissolve during the drying step.
- 4. The method in accordance with claim 2 in which the sheet is post saturated with from about 30% to 100% dry weight pick-up of an organic resin and cured.
- 5. The method in accordance with claim 4 in which the organic resin is melamine modified styrene-butadiene latex having a melamine to styrene-butadiene weight ratio of from about 1:6 to 1:10.
- 6. A mica filled glass fiber web of low porosity consisting essentially of 100 parts by weight of low alkali content glass fibers having diameters in the range of 3-15 microns and an average length of 1/4 to 1/2 inch; from 3-15 parts by weight synthetic organic fibers of an average length of 1/4 to 1/2 inch and deniers between about 1 and 6; 30 to 100 parts by weight mica flakes of a size range between about 20 and 100 mesh; and 5 to 20 parts by weight binder.
- 7. The web in accordance with claim 6 in which the synthetic organic fibers are polyester fibers and in which the binder is poly(vinyl alcohol).
- 8. The web in accordance with claim 6 or 7 wherein the web has been post saturated and cured with from about 30% to 100% dry weight pick-up of an organic resin.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 921,459, filed July 3, 1978, now abandoned.
US Referenced Citations (11)
Continuations (1)
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Number |
Date |
Country |
Parent |
921459 |
Jul 1978 |
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