Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – Producing multilayer work or article
Patent
1997-07-25
2000-01-11
Silbaugh, Jan H.
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
Producing multilayer work or article
2641711, 26417316, 26417126, 4251311, 4253261, 51298, B29C 4904, B29C 7060, B29C 7064
Patent
active
060132221
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for producing sheet material which incorporates particulate matter. In one aspect, the invention relates to a method and apparatus for producing abrasive sheet material.
BACKGROUND OF THE INVENTION
There are uses in many fields for sheet material with particular properties which result from the presence of particulate matter in and, specifically, at the surface of the sheet material. In particular, sheet materials with abrasive particles at the surface are available in the form of rolls or pre-cut sheets of sandpaper or in the form of abrasive discs and belts, and are used to provide anti-slip surfaces for walkways and similar locations. Also, for example, sheet materials with magnetizable particles at the surface are used as magnetic recording media; and sheet materials with reflective particles at the surface are used for pavement marking purposes and for signs. All of those sheet materials are typically produced by comparatively complex coating processes.
Abrasive sheet materials, for example, are conventionally produced by a coating process which typically involves the steps of applying an adhesive to a substrate; depositing abrasive grit particles on the adhesive (optionally using an electrostatic coater to orient the particles); drying and/or curing the adhesive; and, optionally, applying a size coating to anchor the grit particles more firmly in place. The coating process is comparatively slow because it involves multiple coating steps together with long drying and/or curing times, and careful control of the coating conditions is required to ensure the continuous output of an acceptable product. The process may involve the use of organic solvents, the disposal of which should be carefully controlled to reduce the risk of damage to the environment. Moreover, the process does not readily accommodate changes in the various coating materials when it is required to produce a different grade of product.
As an alternative to that process, it has been proposed to produce abrasive products by embedding abrasive grit in the softened surface of a substrate. U.S. Pat. No. 2,712,987 describes a process for making an abrasive belt, in which abrasive particles are distributed over the surface of a nylon substrate softened with a suitable solvent so that the particles become embedded, following which the solvent is dried. U.S. Pat. No. 2,899,288 describes a process for making an abrasive product, in which the upper surface of a thermoplastic backing sheet is softened by heating before abrasive material is spread over the surface and pressed into the sheet between rollers. U.S. Pat. No. 3,813,231 describes a process in which abrasive grit is distributed over the surface of a copolymer film which is then heated in a platen press to bond the grit to the film. U.S. Pat. No. 4,240,807 describes a process in which the substrate is paper coated with a heat-activatable binder which is softened by heating; abrasive grit is then distributed over, and allowed to sink into, the softened binder.
Polymer-based materials in the form of sheets are also known and can be produced simply and economically by extrusion, either through a blown film die or through a slot die. Slot dies can be used to produce comparatively thick cast films and also to coat a film onto a substrate. The extrudate from a slot die may be stretched in the longitudinal and transverse directions (tentered) to produce a film which is biaxially oriented. A blown film die is a ring die with a central passageway through which a required volume of air is admitted into the centre of the extruded polymer tube, causing the extruded tube to expand substantially to form a so-called "bubble". When the polymer has cooled, the expanded tube is collapsed and can then be cut to provide sheeting material of the required shape and size. A method and apparatus for producing blown film are described in, for example, U.S. Pat. No. 5,104,593.
It is known, when using both blown film dies and slot dies,
REFERENCES:
patent: 2328998 (1943-09-01), Radford
patent: 2411724 (1946-11-01), Hill
patent: 2712987 (1955-07-01), Storrs et al.
patent: 2899288 (1959-08-01), Barclay
patent: 3709642 (1973-01-01), Stannard
patent: 3813231 (1974-05-01), Gilbert et al.
patent: 4240807 (1980-12-01), Kronzer
patent: 4302409 (1981-11-01), Miller et al.
patent: 4379806 (1983-04-01), Korpman
patent: 4419014 (1983-12-01), Gale
patent: 4564349 (1986-01-01), Brown
patent: 4603073 (1986-07-01), Renalls et al.
patent: 4648508 (1987-03-01), Neal et al.
patent: 5075061 (1991-12-01), Howell
patent: 5318603 (1994-06-01), Scheider et al.
patent: 5443906 (1995-08-01), Pihl et al.
patent: 5491025 (1996-02-01), Pihl et al.
patent: 5518794 (1996-05-01), Barber, Jr. et al.
Douglas Malcolm F.
Jackson Graham V.
Lenius Steven J.
3M Innovative Properties Company
Busse Paul W.
Poe Michael
Silbaugh Jan H.
LandOfFree
Method of producing sheet material incorporating particulate mat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing sheet material incorporating particulate mat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing sheet material incorporating particulate mat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1459555