CH663762A5 - Writing board with hardened surface - incorporates urea glue methyl cellulose and electro-corundum with hardening agent - Google Patents
Writing board with hardened surface - incorporates urea glue methyl cellulose and electro-corundum with hardening agent Download PDFInfo
- Publication number
- CH663762A5 CH663762A5 CH271884A CH271884A CH663762A5 CH 663762 A5 CH663762 A5 CH 663762A5 CH 271884 A CH271884 A CH 271884A CH 271884 A CH271884 A CH 271884A CH 663762 A5 CH663762 A5 CH 663762A5
- Authority
- CH
- Switzerland
- Prior art keywords
- corundum
- methyl cellulose
- electro
- hardening agent
- writing board
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
- B43L—ARTICLES FOR WRITING OR DRAWING UPON; WRITING OR DRAWING AIDS; ACCESSORIES FOR WRITING OR DRAWING
- B43L1/00—Repeatedly-usable boards or tablets for writing or drawing
- B43L1/002—Repeatedly-usable boards or tablets for writing or drawing chemical details
Landscapes
- Adhesives Or Adhesive Processes (AREA)
Abstract
The writing board has a surface coating to be written on of pressed and hardened material. This is composed of heat-hardening urea glue, a hardening agent controlling the setting time, methyl cellulose as a bonding agent, and fine-ground electro-corundum. The materials can be mixed with water to allow an even painting onto a supporting surface and drying. The whole is then heated and subjected to pressure of 10 to 45 bar for hardening. USE - Particularly in schools, having a long life and allowing easy erasure of markings from pen, pencil or water-soluble felt tip.
Description
BESCHREIBUNG
Künstlich hergestellte Schreibtafeln, weiss oder farbig, die sich mehrmals beschriften und wieder löschen lassen, sind bekannt. Es hat sich aber gezeigt, dass bei intensiver Benützung, zum Beispiel in Schulen, die Schreibfläche ziemlich rasch an Griffigkeit verliert.
Bei vorliegender Erfindung ist die Oberfläche von so hoher Abriebfestigkeit, dass sie über lange Zeit unverändert bleibt. Sie kann mit normalen Blei- und Farbstiften und wasserlöslichem Filzstift beschriftet und ausserordentlich leicht wieder gelöscht werden.
Die Schreibschicht wird als wässerige Lösung, mit Pinsel oder maschinell auf einen Träger gebracht und setzt sich aus folgenden Stoffen zusammen: HeisshärtenderHarnstoffleim, z. B. BASF Kaurit 285, die Abbindzeit steuernder Härter, z. B. BASF 300, Methylcellulose als Binder, z. B. Glutolin Kalle, Elektrokorund fein gemahlen, Wasser zur Bildung einer streichbaren Masse.
Ein Auftrag von 40-50 Gramm pro m2 genügt, wird getrocknetund das Ganze heiss, unterwechselndemDruckvon 10-45 bar bis zur Aushärtung verpresst. Die gewünschte Feinheit der Schreibfläche wird durch Dosierung der Anteile und des Druckes erreicht.
Als Schichtträger für die Schülertafel dient zum Beispiel ein 45 mm starker Maschinenkarton auf den ein liniertes Blatt Papier geklebt wird. Zur erhöhten Druckfestigkeit gegenüber dem Schreibstift wird das Lineaturblatt beidseitig mit obengenanntem Kunstharz beleimt und zur Weiterverarbeitung mit einem dünnen Papier abgedeckt. Auf die getrocknete Tafel wird die Schreibschicht aufgetragen und wie aufgeführt heiss verpresst.
DESCRIPTION
Artificially produced writing boards, white or colored, which can be labeled and deleted several times, are known. However, it has been shown that with intensive use, for example in schools, the writing surface loses its grip quite quickly.
In the present invention, the surface is of such high abrasion resistance that it remains unchanged for a long time. It can be labeled with normal pencils and colored pencils and water-soluble felt-tip pens and extremely easy to erase.
The writing layer is applied to a carrier as an aqueous solution, with a brush or by machine and is composed of the following substances: hot-curing urea glue, e.g. B. BASF Kaurit 285, the setting time controlling hardener, e.g. B. BASF 300, methyl cellulose as a binder, e.g. B. Glutoline Kalle, fine corundum, water to form a spreadable mass.
An application of 40-50 grams per m2 is sufficient, is dried and the whole hot, alternating pressure of 10-45 bar is pressed until hardening. The desired fineness of the writing surface is achieved by metering the proportions and the pressure.
A 45 mm thick machine cardboard, for example, is used as a layer support for the student board on which a lined sheet of paper is glued. To increase the pressure resistance compared to the pen, the ruling sheet is glued on both sides with the above-mentioned synthetic resin and covered with a thin paper for further processing. The writing layer is applied to the dried tablet and hot pressed as listed.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH271884A CH663762A5 (en) | 1984-06-05 | 1984-06-05 | Writing board with hardened surface - incorporates urea glue methyl cellulose and electro-corundum with hardening agent |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH271884A CH663762A5 (en) | 1984-06-05 | 1984-06-05 | Writing board with hardened surface - incorporates urea glue methyl cellulose and electro-corundum with hardening agent |
Publications (1)
Publication Number | Publication Date |
---|---|
CH663762A5 true CH663762A5 (en) | 1988-01-15 |
Family
ID=4240035
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH271884A CH663762A5 (en) | 1984-06-05 | 1984-06-05 | Writing board with hardened surface - incorporates urea glue methyl cellulose and electro-corundum with hardening agent |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH663762A5 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE1016588A3 (en) * | 2005-05-13 | 2007-02-06 | Polyvision Nv | METHOD FOR MANUFACTURING A VISUAL COMMUNICATION BOARD. |
-
1984
- 1984-06-05 CH CH271884A patent/CH663762A5/en not_active IP Right Cessation
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE1016588A3 (en) * | 2005-05-13 | 2007-02-06 | Polyvision Nv | METHOD FOR MANUFACTURING A VISUAL COMMUNICATION BOARD. |
WO2006119592A3 (en) * | 2005-05-13 | 2007-03-08 | Polyvision Nv | Method for manufacturing a visual communication panel having a ceramic surface layer |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PL | Patent ceased |