US2309981A

US2309981A - Apparatus for coating sheet material

Info

Publication number: US2309981A
Application number: US306817A
Authority: US
Inventors: Chester J Randall
Original assignee: United States Rubber Co
Current assignee: Uniroyal Inc
Priority date: 1939-11-30
Filing date: 1939-11-30
Publication date: 1943-02-02
Anticipated expiration: 1960-02-02

Description

Feb. 2, 1943.

c. J. RANDALL v APPARATUS FOR COATING SHEET MATERIAL 2 Sheets-Sheet l mmvrba 66 5976? u. FAA/041A A mRNEYS.

Filed Nov. 30; 1939 Feb. 2, .1943. c. J. RANDALL I APPARATUS FOR COATING SHEET MATERIAL 2 Sheets-Sheet 2 Filed NOV. 30. 1939 INVENTOR/ 095575? FAA/041A BYM a A TTORNEYS.

STATES: PATENT orms 1 l l d' llsg o i rmc SHEET I I Chester J. Randall, Naugatuck, Conn., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey 2 Application November 30, 1939, Serial No. 306,817 scisime. (oral-4s) This invention relates to an apparatus for applying liquids, par icularly rubber containing liqulds, to sheet materials, such as textile fabrics. for the purpose of coating and/or impregnating such materials.-

Heretofore fabrics have been coated by applying the rubber containing liquid to the surface thereof by the use of the doctor blade method,

by theuseof the usual pickup roll which runs in a bath of the liquid and carries it to the surface of the fabric running in contact therewith,

and by coating a surface, such as a belt, with f th rubber containing liquid and then applying the fabric to the coated surface and transferring the liquid coating thereto. In all of the above named [methods it is dimcult; to control the amount of liquid applied to the surface of the fabric. Consequently the thickness of the coating of rubber deposited on the fabric and the degree of penetration of the liquid cannot be accurately controlled. The last named method of coating fabrics also resultsin the loss of the rubber containing liquid due to' some of it sticking to the belt after the fabric has been removed. The control of the thickness of the coating and the penetratio of the rubber containing liquid by the above methods becomes increasingly more difilcult in the treatment of light weight materials, such as knitted or woven fabrics.

In accordance with the present invention the rubber containing liquid is applied directly to the fabric under an hydraulic head which transmits the liquid to all surfaces of the fabric under a uniform pressure which can be accurately controlled by controlling the quantity of liquid supplied, and thereby uniformly coat or penetrate the surface of the fabric to the predetermined extent desired. I

The above and other objects of this invention will be more clearly understood byreferring to the following description and the accompanying drawings, in which:

Fig. '1 is a semi-diagrammatic side elevation of the complete apparatus;

Fig. 2 is a semi-diagrammatic plan view thereof 4 Fig. 3 is a section on line 3--3 of Fig. 1;

Fig. 4 is a view of .a section of an applier bar taken in perspective from above; and

Figs. 5, 6 and 7 are cross-sectional views of the coated fabric illustrating, respectively, a light coating, and difierent degrees of penetration pro duced by the rubber containing liquid.

Referring to Fig. 1 of the drawings, the sheet material III or fabric to be coated, is led from areel ll underneath a pair of rollers l2 and I3 which are supported on a table l4. The material I is drawn from the roll l3 up one side of an applier bar I and down the other side by a driven 'roll l6. As the material is drawn over the bar IS a liquid, suchas a rubber containing liq- .uid, adapted to produce'a coating on the fabric when dried is forced from the interior of the applier bar and applied to the under surface of the material 10. The cylindrical surface of the roll [6 is covered with a material adapted to resist the slippage of the fabric thereon. As shown in the drawings, the cylindrical surface of the roll I6 is covered with what is commonly known as card clothing material having relatively small, sharp and, closely spaced pins anchored in a fabric backing which is placed adjacent to the roll so that the pins project from the periphery of the roll and contact with the material Ill. sheet material It passes from the roll l6 over a roll I! and then over a heating surface I8, where the coating is dried. The sheet material It! is supp rted over the heating surface 18 by a pluralityof small rolls 19. The coated material It] then passes underneath a roll 20 and is wound up Three samples of the finished. coated fabric, impregnated different amounts, are shown in Figs. 5, 6 and '7. As shown in Fig. 5 the finished rabric 22 consists of a, light, coating 23 of rubber composition applied to the fabric II]. In this case the fabric is penetrated to a very small extent. Fig. 6 illustrates a finished fabric 24 having a coating of rubber 25 which penetrates the fabric It) to about one-half its thickness, and Fig. '7 illustrates a fabric 26 in which the textile fabric It) has been completely penetrated and provided with a coating 21.

The coatings of rubber 23, 25 and 21 in Figs. 5, 6 and 'l are deposited upon the under surface of the fabric l0 from a rubber containing liquid which is applied to the fabric by means of the applier bar l5 which is shown in detail in Figs. 3 and 4. The applier bar l5 has a transversely rounded upper surface which is provided with a longitudinal groove 28 over which the fabric is drawn by the driven roll l6 and held in contact with the edges of the groove by the roll I3 and the driven roll [6. The rubber containing liquid is supplied to an internal chamber 29 in the applier bar IS. The chamber 29 is connected with the groove 28 by a restricted throat 30 which extends substantially the length of the groove 28 and causes back pressure to be built up in the chamber 38 and evenly distributes the The rubber containing liquid under a uniform pressure throughout the length of the groove 28. The hydraulic pressure placed upon the rubber containing liquid in the chamber 29 is so controlled that the groove 28 is completely filled with the rubber containing liquid at all times. The liquid is thereby continuously maintained in contactwith the bottom surface of the fabric I as it is drawn over the bar I5. An undercut groove 3| is formed in the applier bar l and it is provided with an upper edge 32 which extends along the line where the fabric breaks contact with the upper surface of the bar. The top surface of the edge 32 extends substantially parallel with, or tangentially to, the bottom surface of the fabric and prevents the rubber containing liquid from pulling away from and stringing after the fabric as it leaves the top surface of the bar IS.

The rubber containing liquid is supplied to the bar l5 from a tank 33 which is connected .to a pump 34 through a pipe 35. Thepump 34 delivers the rubber containing liquid through a pipe 36 and its branches 3'! (Fig. 3) to the chamber 29 in the bar l5, and thence to the groove 28. For the purpose of insuring a free flow of rubber containing liquid from the tank 33 to the pump 34, air under the desired pressure is supplied to the top of the rubber containing liquid in the tank'33 through a pipe 38.

The hydraulic pressure or the quantity of rubber containing liquid delivered to the groove 28, in a unit of time is controlled by the speed at which the pump 34 is driven, and the quantity of rubber containing liquid applied to the unit area of the fabric ID as it passes over the applier bar l5, for a given rate of fiow of liquid, is controlled by varying the speed at which the fabric I0 is drawn over the bar l5. For this purpose the roll I6 is driven by a motor 39 which drives the variable speed drive 40 through a sprocket and chain drive 4|. The variable speed drive 40 is connected to the shaft 42 of theroll l6 by means of a sprocket and chain drive 43. The speed at which the fabric is drawn over the bar l5 by the roll I 6 may be controlled by varying the ratio of the driving to the driven speeds in the variable speed drive 40 by means of the hand wheel 44.

The pump 34 is driven through a variable speed drive 45 on the opposite side of the machine from the variable speed drive 40. The variable speed drive 45 is driven from the shaft 42 of the roll l6 through a sprocket and chain drive 46. The variable speed drive 45 is directly connected to the pump 34 through the sprocket and chain drive 41. The speed of the pump 34 and consequently the rate of flow of rubber containing liquid and the hydraulic pressure maintained thereon may be varied by changing the ratio of the driving to the driven speeds in the drive 45 by operating the hand wheel 48.

Wherever the term rubber containing liquid is used herein it shall include rubber cements and suitably compounded latex which latter broadly designates coagulable aqueous dispersions of elastic materials, including artificial dispersions of rubber or rubber-like materials as well as natural latex, which may be preserved or compounded or otherwise treated as desired, as by vulcanization, and which may be in a normal, diluted,

' bar having a transversely rounded upper surconcentrated or'purifled condition produced by methods well known in the art.

As shown herein the pump 34 is of the rotary type which produces a uniform flow of liquid without pulsations. Such pump is suitable for pumping rubber cement but as is well known it is not suitable for pumping rubber containing liquids, such as latex, which-coagulate upon the blades of the pump. Where it is desired to use latex in.this system the pump 34 is taken out of the

pipe line

35 and 36 and the tank 33 is directly connected to the chamber 29 in the applier bar I 5 by the

pipes

35 and 36. Sufilcient air pressure is applied through the pipe 38 to the top of the latex in the tank, and the pressure is controlled in any well known manner to cause the latex to fiow'at a predetermined rate to the bar l5.

While this invention has been described in detail it will be understood that changes may be made, and it is desired to claim the invention as broadly as permitted by the prior art and as covered by the scope of the appended claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. An apparatus for applying liquid to the surface of sheet material comprising a support for said material, said support having a transversely rounded upper surface provided with a groove extending lengthwise thereof, means for drawing the material across said groove and in contact with the edges thereof on said support, said rounded surface having an undercut groove therein provided with a top edge extending parallel with said groove and along the line where the sheet material breaks contact with the surface of the support, and means for supplying said groove with liquid so as to maintain the liquid continuously in contact with the material.

2. An apparatus for applying liquid to the surface of sheet material comprising an applying face provided with a groove extending lengthwise thereof, a roller on each side of the said bar so arranged that the material passes underneath the rollers and over the bar and is thereby maintained in contact with the edges of said groove, means for pumping liquid into said groove, means for controlling thequantity of liquid pumped, means for drawing said material underneath said rollersandover said bar, and said pumping means being driven from said drawing means so that any change in speed of said drawing means will cause a proportional change in the speed of said pumping means.

3. An apparatus for applying liquid to the surface of sheet material comprising an applicator for said material, said applicator having a transversely rounded surface provided with a groove extending lengthwise thereof, means for drawing the material across said groove and in contact with the edges thereof on said applicator, said rounded surface having an undercut groove therein provided with an edge extending parallel with said groove and along the line where the sheet material breaks contact with the surface of the applicator, and means for supplying said groove with liquid so as to maintain the liquid continuously in contact with the material.

CHESTER J. RANDALL.