US2220140A - Abrasive sheet material - Google Patents

Description

Nov. 5, 1940. H. G. BARTLING ET AL ABRASIVE SHEET MATERIAL original Filed Jan. 29, 1929 Patched Nov. n5, 1940 UNITED STATES PATENT OFFICE AaAsIvE snnE'r MATERIAL Delaware Continuation of application Serial No. 335,999,

January 29, 1

929. VThis application March 15, 1933, Serial No. 660,890

5 Claims. (Cl. 51-303) This invention relates to improvements in flexible, abrasive sheet material commonly known in the trade as abrasive paper or cloth, such as sand, flint, emery, garnet and aitici'al abrasives, and in the method of manufacturing the same, and one of the objects of the invention is to provide an improved abrasive sheet material of superior quality having great flexibility and durability, without possessing any objectionable qualities such as cracking or tearing of the material, and which will be highly resistant to deterioration or wear.

Heretofore abrasive material of ,thisY character usually comprises a base of a flexible sheet fabric or paper to which grit or a layer of abrasive particles are applied and secured by means of a binder interposed between the sheet and theo abrasive particles, the binder having certain characteristics according to the nature of the work to be performed. that is, for wet or dry Work.

This application is a continuation of our application S. N. 335,999 illed January 29, 1929.

With such material considerable dimculty and inconvenience has been experienced as the frici tion between the sanding element and work causes injury to binder and the abrasive particles quickly become detached. Furthermore, the fabric or paper may quickly wear or become torn. If heavy fabric or paper is employed as a base, the work', and especially the nner or higher grade oi' work, might be marred, scratched or otherwise injured thereby.

It is one of the objects of the present invention to provide an improved abrasive sheet material in which the bond or binder and the fabric or paper will be dispensed with, and the abrasive material will be attached or secured in position to a flexible body portion by means oi the in- .herent qualities of the material or substance constituting or forming the body portion of the sheet material.

A further object is to provide an improved abrasive element embodying only a flexible body portion and an abrasive element applied and secured thereto or embeddedmtherein without the employment of an adhesive 6r binding material between the body portion of the element and the abrasive material.

In carrying the invention into operation the body portion of the abrading element is formed of a flexible material such as cellulose or any other suitable substance which initially is `preferably in the form of a liquid of any desired consistency, and preferably a plastic material capable of clinging to a surface while drying, the substance being of such a nature that an abrasive may be applied thereto or mounted thereupon. The substance of which the body portion is composed should also be of such a nature and material that after the solvents have been evaporated it may be stripped or removed from such surface and when rem'oved will be flexible and of any desired thickness with the abrasive firmly attached or secured thereto. The cellulosic material which we may employ may be cellulose nitrate, cellulosexanthogenate or cellulose acetate, all of which are reactive to the normal solvents therefor. If desired, these materials may be reinforced by the addition of vai-- ious gums or gum resins. The solvents which we may employ may be acetone, with or Without a ketone, and any other of the vknown solvents for these cellulosic materials. These cellulosic materials have the characteristic of relatively rapidly solidifying when formed into a layer, the side of which contacts an adjacent surface as will hereinafter appear, solidifying before the exposed surface.

The liquid is manipulated or formed in any desired or suitable manner into a sheet of any desired length, width and thickness and is subjected to a drying operation preferably so that one side or face thereof will dry more rapidly than the other, and suiciently to permit the material to be advanced or moved forward, and at the same time leaving the top surface tacky or sticky To this surface, before the same becomes dry, is applied in any suitable manner, deposited thereupon, or embedded therein, the abrasive material, preferably in the form of sand,remery, flint or garnet, or like material, or the artificial abrasives which are used in many instances, in preference to the natural abrasives mentioned.

As the material forming the body portion of this product solidies or dries into the exible l sheet, the grit or abrasive material becomes fastened or secured thereto by the inherent qualities of the material forming the body portion of the element, and the abrading material will be fastened to the body portion more securelythan if an, adhesive is applied to secure the abrading material to a cloth, paper or other backing.

Furthermore, with the present invention the product consists of buttwo elements, one of which is a flexible substance, preferably though not necessarily non-metallic, and the other an abrasive material, the two being fastened or se- Y while the latter is plastic or semi-dry, it willbecome a part of the flexible body portion as the cured together without the added use of adhesives, /binders or backing.

As the abrasive is applied to the body portion,

latter solidies or hardens through evaporation of the solvents therefrom.

During the operation the material will harden or solidify around the atoms or particles of the abrading material and firmly hold or secure them to the surface of the body portion of the element.

This abrasive sheet may also be producedn in another manner as the plastic or semi-plastic body portion may be formed and allowed to become partially or thoroughly dry or solidified,

and at a subsequent time apply the abrasive to the `surface thereof.

If this latter method is employed, then one face of the body portion thus produced may be dampened with the liquid of Ithe same material as the body portion, or with a solvent in a liquid state so as to render the surface of the body portion sticky or tacky, after which the abrasive material may be 'deposited upon, applied to or embedded in such surface in any desired manner. A further drying or solidiiication ofthe product thus produced will cause the particles of the body to firmly grip around the atoms or particles of the abrasive material.

If desired and in order to reinforce the body portion of the abrading element, a iiexible reinforcing element, preferably, although not ncessarily non-metallic, may be embedded or molded therein with the body portion of the abradin'g element formed around or about the same.

The methods disclosed herein for producing an abrasive article of, this invention may be carried out by various apparatus and in the figures of the drawing we have illustrated embodiments of apparatus for producing an abrasive article of the character described herein.

In the drawing:

Figure 1 is a diagrammatic view-of apparatus for carrying out one of the methods disclosed herein.

Figure 2 is a modified form of the invention and Figure 3 is a still further modied form.

Referring now to Figure l, there is provided a carrier or conveyor, preferably of av n exible but stable nature indicated at 5, said carrier having a relatively smooth exposed upper surface 6, t which is applied the cellulosic compound forming the backing of the abrasive article to be produced, the path of the conveyor 5 being changed in directionas indicated at 1 by passing over a suitable roller or over propelling means.

above the conveyor,` and spaced the desired distance therefrom we provide a hopper 8 for binder material which is extended to serve the purpose of the backing herein described This backing material, preferably of a cellulosic character, is indicatedflowing in plastic form from the hopper V8 at 9 into a layer I0 on the conveyor 5.

Owing to the nature of the adhesive employed the back surface thereof in contact with Ithe belt or conveycr 5 has a tendency to solidify or harden more rapidly Whrre it contacts at I2 with said conveyor than at its outer surface I3; the outer surface remains in a plastic or semi-plastic state as the backing material or binder passes beneath the hopper I4, which hopper is adapted to contain a-pulverulent abrasive material I5 for deposition on the backing I!) which abrasive is applied to the plastic surface of the backing I touform a layer of abrasive I6.

As the layer or backing I0 having the grit incorporatedtherein movesalong the conveyor by adhesion thereto and approaches the deflected portion 1 of the conveyor,y the backing engages a stripping blade I1 positioned so as to have its reduced edge I8 presented tangentially to the conveyor thus stripping the backing and its grit layer from the conveyor.

In order to cause the Vpreliminary setting of the backing or to hastenthe setting of" the tacky surface of the backing I0, cooling air blasts may be directed against the underside of 'the conveyor as indicated at I9 and 20. 20.

The air blast delivered from the nozzle I9 is applied before the layer of binder material reaches the point of deposition of the grit and the other air blasts 20 are applied after the binder passes the grit hopper.

It will be understood ,that the conveyor may Vbe of any desired length depending upon the ingredients employed in the backing layer and Ithe time interval betweenthe deposition of bin'der and deposition of grit required to produce the desired results. An auxiliary drying nozzle 2I may be provided if desired for hastening setting kof the backing at the end of the flight to -the conveyor. i n

Referring now to Figure 2, the assembly here issubstantially the sameas that shown in Figure 1 and a detailed description of all of the parts thereof is therefore not included. For some purposes it may be desired to allow the backing I0 nto become st beforereceiving the grit, but if this is done as hereinabove explained, the'means for supplying a solvent in a liquid state for rendering the exposed surface of the backingy I0 tacky may be employed. Such a means is. dise closed at 22 and includes a nozzle controlled by valve 23.

Referring now to Figure 3, the apparatus therein disclosed is substantially the same as that shown in either Figure 1 or 2, or both, as may be desired, a conveyor 5a being provided having a divergent portion 1a. y

Upon the conveyor 5a is applied a backing or reinforcing element 25 and this element is moved by any suitable means along with the conveyor 5a beneath the binder-containing hopperl 26 and the grit-containing hoppier 21.

The binder layer of cellulosic material or the like is shown at 2B issuing from the hopper 26 and adapted to receive the grit layer 29 supplied from the hopper 21. y

If desired, a process of moistening the exposed surface 30 of the binder layer 28 may be resorted to by the provision of the solvent delivering nozzle 3I shown in dotted lines.

It will be understood that the several forms of the apparatus-are purely diagrammatic and may be varied structurally to suit conditions of operationin the course of actual manufacture of the abrasive article.

ticles become a part of ythe body portion without ,manner in which a backing and the provision of a' binder or adhesive between the body portion and the abrading particles will be dispensed with.

What is claimed as neW is:

1. The method of manufacturing flexible abrasive material which consists in providing a substance in plastic form, then shaping said material by casting and partially solidifying the same progressively from the casting surface and leaving an exposed surface unsolidied, then applying abrasive particles to the unsolidified surace, and then completely solidifying such surace.

2. The method of manufacturing flexible abrasive material which consists in providing a nonmetallic substance in plastic form, then shaping said material by casting and partially solidifying the same progressively from the casting surface and leaving an exposed surface unsolidified, then applying abrasive particles to the un- 4solidied surface, and then vsolidifying such surface by evaporating the solvents therefrom, and solidifying the entire article so cast with the abrasive particles in situ.

3. The method of manufacturing abrading material which consists in casting upon a continuously moving surface a plastic mass from a liquid which adheres to said surface and becomes a flexible substance after evaporation of its solvents, then applying abrasive particles to the exposed face of such substance so cast While said face is still in a plastic state, then evaporating the solvents, the abrading particles being'l secured to such substance solely by solidifying the adjacent portion of the substance about said particles, and then removing the cast body portion with the abrasive fastened thereto, from the surface upon which the body has been formed.

4. A process for forming an abrasive article which includes as steps thereof, forming a plastic body on a movable conveyor, and causing same to adhere thereto, drying or setting one surface of said body to provide a cast surface While leaving the other surface tacky, applying a layer of abrasive particles to said tacky sur-r face, and then setting the body for retaining the abrasive particles therein and removing said body from the conveyor along the cast surface.

5. The method of producing exible sheet abrasive material which consists of casting upon a continuously moving supporting' surface a plasa solid iexible mass that will retain abrasive grains embedded in the surface thereof, then applying abrasive grainsv to the surface of the plastic mass before it becomes too hard to receive said abrasive grains, then hardening the plastic mass by evaporating the solvent, and then removing the 1hardened plastic mass from the supporting surface. g

' HOWARD G. BARTLING.

EILSWORTH B.` OVERSHINER.

" tic mass of liquid consistency in a volatile solvent,which is capable of being converted intov ORRTIRIOATR OF CORRECTION. Patent No. 2,220,1LLO. November 5, 19m.

HOWARD G. BARTLING, RT AL.

is hereby certified that error appears in the printed specification of' the above numbered patent requiring correction as follows: Page 5, first column, line 18, claim l,'after"f`ace insert and the material with the abrasive particles in situ; and that the said Letters Patent should be read with this correction therein that the same may conform to the record Of the Case 4in the Patent Office.

Signed and sealed this 7th day of' September, A. D. 19MB.

K Henry Van Arsdale (Seal) Acting Commissioner of Patents.

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