Method of making a gas permeable material
US5925406A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Jul 18, 2017 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD06N2209/121
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of making a gas permeable material having a diffusive gas permeability at 0.21 atmosphere diffusive driving force in the range of about 0.5.times.10.sup.5 cm.sup.3 /100 square inches/day to about 2.times.10.sup.5 cm.sup.3 /100 square inches/day. The method comprises the step of coating a pattern of spots of a gas impermeable material onto a porous substrate, followed by a step of enlarging the pattern of spots to cover greater than about 95% of the porous substrate such that the gas permeability occurs only through openings between the pattern of spots. The gas impermeable material is preferably a hot melt adhesive and the porous substrate is preferably a nonwoven. The step of enlarging the pattern of spots includes smearing substantially circular spots into oblong spots as the pattern of spots is printed onto the porous substrate until the oblong spots partially overlap. The smearing is achieved by operating a printing screen at a surface speed higher than a draw rate of the porous substrate. Alternatively, the step of enlarging the pattern of spots includes calendering through a fixed gap the porous substrate after the pattern of spots is coated thereon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.