Process for the production of entry sheet for drilling and entry sheet
US9986644B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2009 |
| Grant date | May 29, 2018 |
| Priority date | — |
| Expiry date | Aug 12, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249953
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A process for the production of an entry sheet for drilling a printed wiring board material, which process comprises forming a multi-layered water-soluble resin composition layer on at least one surface of a metal foil, wherein an aqueous solution of a water-soluble resin composition is applied to the metal foil, dried and solidified to form one water-soluble resin composition layer, the application, drying and solidification of the aqueous solution of the water-soluble resin composition are repeated at least once to form at least one water-soluble resin composition layer on the above one water-soluble resin composition layer, the multi-layered water-soluble resin composition layer is composed of these water-soluble resin composition layers, the multi-layered water-soluble resin composition layer has a thickness of at least 50 μm and is almost free from air bubbles, and an entry sheet for drilling a printed wiring board material obtained by the above process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.