US 2107276 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Feb. s, 1938. T, ANDERS N 2,107,376
VERTICAL COATINGEQUIPMENT Filed July 28, 1936 Wz'i/iam 7. Anderson INVENTOR ATTORNEY.
. 45 vation view of a coating head Patented Feb. 8, 1938 UNITED STATES 2,107,276 VERTICAL COATING EQUIPMENT 7 William T. Anderson, llggertsville, N. Y., assignor to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware,
Application July 28, 1936, Serial No. 92,989
This invention relates to machines for coating flexible sheet material and more particularly to improved equipment for coating cloth with a cellulose derivative composition.
This invention may be considered an improvement or modification of the apparatus described in U. S. Patent No. 1,857,241 issued to William H. Edmondson. In conventional coating machines the fabric to be coated is unwound from a roll and passed over suitable supports to a coating head where the composition is applied by supplying an excess before a doctor knife. The composition is thereby spread over the sheet material in a more or less uniform layer. Disad- 16 vantages of these machines are that the composition runs over the edges of the material being coated and does not always coat the extreme edges uniformly.
This invention has as an object the provision 20 of apparatus which coats fabrics, whether delicate or heavy, uniformly even to the edges.
A further object is the provision of apparatus which simplifies the coating operation by the elimination of a container located in front of the doctor knife for the coating composition.
A. still further object is the provision of an apparatus the use of which insures an exceptionally uniform application of the coating composition by means of specially designed knives.
30 A still further object is the provision of equipment in which the axis of the knife holder remains in a fixed position for coating with the various types of knives with respect to the relation between its edge and the fabric to be coated.
35 Other objects will appear as the description of the invention proceeds.
These objects are accomplished by means of an improved coating head placed before the standard or other drying arrangement. This im- 40 proved. coating head is arranged to coat the sheet material while it moves in a substantially vertical plane before it enters the drying chamber.
' In the drawing, Figure 1 represents an end elewith the parts arranged according to the present invention. Figures 2 and 3 are detailed views of the knife 5 in Figure 1. These figures represent a full round or .dull blade and a modified dull blade redo spectively as will be more fully described later.
In Figure l, l represents the sheet material to be coated, IZ representsnip rolls which guide the material I around the tension rolls l3, 3 is a smooth roll over which the material passes and which provides a means of adjusting the angle of incidence formed by the material being coated and the doctor knife, 4 represents a screw by means of which the roll 3 may be raised or lowered to change the angle of incidence, and 5 is a doctor knife mounted in the holder 6. The angle which the doctor knife makes with the cloth or other material being coated may also be varied by means of the 'worm l, 8 represents the composition which is being applied to the sheet material, and 9 is a guide roll. The roll it! is a rubber-covered, driven friction roll which assists in drawing the fabric past the knife, II is a heated drying chamber.
In the operation of the apparatus according to the present invention, the fabric such as cloth which is to be coated is unwound from the unwind and passed over the tension rolls E3. The material then passes over roll 3 and under the edge of the doctor knife 5 which may be ground to any form depending on the amount of composition desired to be deposited on the fabric.
There are also provided ears, not shown in the drawing, mounted on each end of the knife holder 5. The ears" are approximately 4" to 6" wide in the direction of the width of the mate- 7 rial so as to prevent the jelly roll 8 from approaching the edges of the web being coated except in limited amounts as determined by undercutting the ears in a diagonal manner to taper the jelly roll slowly to a point near the selvage or edge of the web.
This machine is particularly adapted to coating fabric with cellulose derivative compositions. These compositions are usually prepared in a form having the consistency of a jelly and may be eith clear or pigmented. The amount of 'composi ion deposited can be varied by increasing the tension of the fabric I. This may be done by adjusting the tension on the unwind, not shown in the drawing, or by changing the position of the coating knife. The amount of composition deposited may also be varied by the shape of the edge of the knife 5 which is in contact with the fabric to be coated. It is preferred that the edge have the form of an arc of constant radius even in cases where a comparatively sharp knife is used for special purposes. In general, it may be said that the smaller the radius of curvature of the arm in contact with the cloth the less composition will be applied.
After passing under the knife blade, the material enters a heating chamber where the solvents are volatilized and recovered. The heating chamber ll may be of any conventional type or that disclosed in the copending application Serial No.
ing an edge of such shape that the cloth follows exactly the entire edge thereby increasing the.
contact area of the doctor blade and the sheet material, giving a heavier and smoother. coat than is possible with former type knives. It is also possible to apply a thin coating on the fabric by using a knife the edge of which has a constant radius but with a portion of the are cut away. When this has been done, the knife is .usually designated as A round or or A round as the case may be. When none of the edge has been removed but a section through the blades shows an edge which resembles a semi-circle, it is called a full round knife. By using such a knife, a heavy smooth coat of cellulose derivative composition may be applied which heretofore could only be accomplished by more than one pass through the coating head.
The knife bar, if preferred, may be constructed by coring out a portion and fitting it to hot and cold water connections so that the optimum temperature of the jelly at the doctor blade may be maintained.
The apparatus herein disclosed presents the advantage that the coating composition container may be eliminated which in turn saves time in cleaning and changing from one color or type of composition to another with less loss of running time and coating compositions.
Another advantage is that by use of the driven friction roll immediately following the coating knife there is less tension on the fabric being coated as it travels onward through the drying equipment. This is advantageous because it reduces the tension on the warp threads, while the fabric is passing through the drier, thereby resulting in little or no pull down in width of the cloth. As a result it is possible to use cloth of a narrower width than required by machines which do not have such a driven friction roll. The so-called "rib effect, which is an imprintof the goods showing through the coating, is practically eliminated.
A further advantage is that the axis of the rotatable knife holder remains in a fixed position and may be used for the various types of knives used in coating. The rotatable knife holder affords access to knives for cleaning and changing.
' The uniform arc of contact with the knife edge permits the coating of very thin fabrics which could be coated only with great difiiculty in the conventional t'ype machines. A still further advantage resides in the fact that knives having a uniform radius have a much longer life and in that the knifeis worn away uniformly without change in the shape of the edge and does not require frequent grinding. This isa costly operation since great care is necessary in grinding these knives in order that a uniform film of composition will be applied. Moreover, the knives having a. large contact surface area are not easily dented or nicked as is the case with the sharp,-
As many apparently widely different embodiments of the invention may be made without departing from its spirit and scope, it is to be understood that the invention is not limited to the specific embodiments hereinbefore set out, except as defined in the appended claims.
1. Apparatus for coating fabrics which comprises a doctor knife, means for passing a fabric in a substantially horizontal direction before contact with the knife, andmeans for moving the said fabric in a substantially vertical direction after contact with the said knife.
2. Apparatus for applying cellulose derivative coating compositions to fabric 'which comprises means for drawing the said fabric over an adjustable guide roll and idler rolls and a coating knife disposed between two of the rolls such that the fabric approaching the knife passes in sub-- stantially a horizontal plane and the fabric leaving the knife passes in substantially a vertical plane.
3. Apparatus for applying a cellulose derivative coating composition to fabric sheet material' which comprises means for passing the said fabric over an adjustable guide roll, means for passing the fabric in substantially a horizontal plane to a doctor knife and means for passing the fabric after it'leaves the doctor knife in substantially a vertical plane over guide and friction rolls to a heating chamber. a
4. Apparatus of claim 1 in which the edge of the knife only in contact with the fabric has a constant radius. r
5. Apparatus of claim 2 in which the edge of the knife only in contact with the fabric has a constant radius.
6. Apparatus of claim 3 in which the edge of the knife only in contact with the. fabric has a constant radius. A
7. Apparatus for applying a cellulose derivative coating composition to a fabric sheet which comprises means for passing the said fabric over an 0 adjustable guide roll, means for passing the fabric in a substantially horizontal plane to a coating knife and means for passing the fabric after it leaves the said knife in substantially a vertical plane and a driven friction roll to assist in drawing the fabric under the knife.
8. The combination of means for passing a fabric in a horizontal direction and in a substantially verticaldirection and a doctor knife having a rounded edge which is a portion of thearc-of a circle, said cloth bearing against the said roundrection of the cloth changes from horizontal to 7 ed edge of the knife at the point in-which the di- CERTIFICATE OF CORRECTION. Patent No 2,107 276. February 8, 1938.
WILLIAM T ANDERSON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, line L 9, for the word "arm" read arc; and that the s aid Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in the Patent Office Signed and sealed this 12th day of April, Ao D. 1958.
Henry Van Arsdale (Seal) Acting Commissioner of Patents.