US 3152387 A
Description (OCR text may contain errors)
Oct. 13, 1964 J. A. MACLEOD 3,152,387
ROLLERS Filed Oct. 16, 1961 INVENTOR. JOHN A. MACLEOD MWM ATTORNEY United States Patent 3,152,387 ROLLERS John A. Macleod, Dundee, Scotland, assignor to l )ayc0 Corporation, Dayton, Ohio, a corporation of Gino Filed Set. 16, 1961, Ser. No. 145,250 12 Claims. (Ci. 29-13%) This invention relates to rollers, and more specifically to resilient rubber dampening rollers for lithographic offset presses, slasher rollers for textile processing, and the like.
In certain processes the transfer of liquid solutions is important. For example, lithography requires a means for supplying water to a printing plate, the water being applied to those portions of the plate not bearing the printing image in order to prevent the inking of these parts of the plate. The water repels the ink (usually oil base) from these non image-bearing portions and keeps them clean. It has been customary for many years to use dampening rollers for this purpose, and the conventional dampening roller has an obsorbent cover made of cotton or similar material which is sewn over a rubber-coated metal core. The fabric thus acts as a water reservoir and provides the necessary dampening effect. It is quite obvious that the use of a cover for dampening purposes leaves much to be desired. For example, such a roller tends to wear the printing plates because of its hardness. Another disadvantage lies in the ditiiculty of controlling the amount of liquid which is deposited on the plates. A third disadvantage and an important one is the necessity for removing the cover periodically when it has become compressed or impregnated with the oily ingredients of the ink, thereby cutting down on its Water absorptive capacity. When this happens the cover must be removed and replaced, thus entailing not only a replacement cost but resulting in extensive down time which is very costly in modern high-speed printing operations.
In order to eliminate the need for this separate cover, applicant has invented a new type of dampening roller which is a single member; that is, the outer layer of the roller acts as the dampening means. This is accom plished by forming the outer layer of a resilient, compressible material such as natural or synthetic rubber, throughout which is distributed a fibrous material such as a fiber flock that is hydrophilic in nature. In order to enhance the efiect of this flock, it is important to use a hydrophilic plasticizer in contrast to the conventional hydrophobic plasticizers. It has been suggested in the prior art that water absorbent particles or fibers be used for similar purposes, as described for example in US. Fatent No. 2,119,491, issued May 31, 1938, to Rapport; the present invention, however, constitutes a considerable improvement over this earlier step in the combination of plasticizer and flock material. The fiber flock is the physical means by which a large body of water is held by capillary action throughout the entire layer. The hydrophilic plasticizer provides the chemical means which provides the unexpected result of cooperating with the fibers to effect retention and immediate release of the liquid solution instead of permitting the fibers to hold the solution indefinitely.
It is, therefore, a principal object of the present invention to provide an improved roller having an outer layer which can be used for transferring moisture from a liquid reservoir to a contacting member.
It is further object of the invention to provide a roller for moisture transfer, having an integral outer layer to eliminate the need for changing covers.
It is further object of the invention to provide such a roller which will minimize wear on the contacting surfaces.
Further objects will be apparent from the following detailed description and drawings, in which:
FIGURE 1 is a perspective view of a roller embodying the features of the present invention.
FIGURE 2 is a section of the novel roller taken along lines 22 of FIGURE 1.
Turning now to the drawings, FIGURE 1 illustrates a roller 11 made in accordance with the present invention. As is shown in FIGURE 2, this roller consists of a base or inner layer 12 which is made of fairly hard rubber (approximately -90 Shore A durometer hardness). Surmounting the inner layer is a central layer 13 which is considerably softer (approximately 30-40 Shore A durometer hardness) and forms a cushioning eifect against the inner layer. A third (outer) layer 14 surmounts layer 13, and this layer has a hardness 50-60, about half-way between that of the other layers. Distributed throughout this outer layer are fibers 15, such as rayon flock, which are compounded directly into the outer layer. After the three layers are assembled by conventional means, they are vulcanized together to form a unitary product. In final use this product will be placed on a metal core which is a part of the overall apparatus, such as lithographic or textile finishing system.
The outer layer may be formed by compounding the ingredients in a mill in conventional fashion, then extruding into a tube of desired dimensions, or may be formed by calendaring and laminating. Typical formulation for the outer cover is listed below:
Example N 0. 1
Parts by weight Butadiene-acrylonitrile copolymer Zinc oxide 5 Titanium dioxide 5 Brown factice l0 Other formulations found workable are listed below:
Parts By Weight Examples Nos 2 3 4 5 6 Butadiene-acrylonitrile o0polymer 100 108 105 Zinc Oxide 6 5 6 5 5 Titanium dloxide 6 5 6 5 5 Brown factice 11 11 11 11 10 Powdered siliea 22 20 22 21 20 Aceelerator 1. 25 1. 25 1. 25 1. 25 1v 25 Sulfur 2. 5 2. 5 2. 5 2. 5 2. 5 Rayon flock (8 de er, eh) 60 60 40 30 25 Plasticizer (diethylene glycol monobutyl other formal) 15 30 30 50 60 Generally speaking, it has been found that a practical product is provided by flocking materials ranging from about 10% to 25% of the compound by weight. The plasticizer referred to above may be employed in the range of about 7% to 25% by weight. It should be further noted that in lieu of rayon, other hydrophilic materials, such as cotton, may be used, and various diameters and length of rayon or cotton may be substituted for the example given above as long as the product is small in diameter and short in length.
The hydrophilic plasticizer listed above is an example of an ester reaction product of a polyhydric alcohol such as a glycol or substituted glycol and an acid. The acid may be any of the unsaturated fatty acids such as oleic, caproic, caprylic, capric, lauric, palmitic, stearic, and the like; or one of the poly carboxylic acids and aromatic carboxylic acids such as phthalic acid, and any hydrides thereof. The glycols which may be employed to form the ester may be methyl glycol, dimethyl glycol, ethylene glycol, diand tri-ethylene glycols, etc. Esters of the alcohols and acids above described which have operated satisfactorily, include dimethyl glycol phthalate, triethylene glycol di-caprylate, and methyl glycol oleate. In addition, aldehyde modified glycol ethers such as the one previously mentioned, may be employed; for example, the acetate or the ethyl ethers, and ethyl ether acetates as well as methyl ether modifications and the like.
It can thus be seen that my invention provides a unique product in which. a hydrophilic plasticizer and hydrophilic fabrous materials cooperate to furnish a roller capable of transferring liquid solutions, such as Water. Such a roller retains the solution until needed, then releases it to contacting surfaces. When used in litho graphic processes, it can provide many hours of use and minimize shut-downs. When the surface becomes con- Laminated, it may easily be cleaned by use of a suitable solvent.
1. A roller having an outer surface layer comprising a resilient rubber body, a hydrophilic plasticizer incorporated therein, and a hydrophilic fibrous material conipoundedtherewith, said plasticizer and said fibrous material cooperating to effect retention and release of liquid solutions.
2. The roller of claim 1 in which said plasticizer comprises approximately 7% to 25% of said body by weight.
3. The roller of claim 1 in which said plasticizer is diethylene glycol monobutyl ether formal.
4. A roller having resilient rubber inner, central, and outer layers, said inner layer having greater hardness than said central and outer layers, said outer layer having a hydrophilic plasticizcr compounded therewith and hydrophilic fibrous material incorporated therein.
5. A roller having an outer surface layer comprising a resilient rubber body having distributed therethrough approximately 10% to 25 by weight of fibers, said body having a diethylene glycol monobutyl ether formal plasticizer compounded therewith.
6. The roller of claim 5 in which said plasticizer comprises between 7% and 25% of said body by weight.
7. A roller having an outer surface layer comprising a resilient rubber body, said body having compounded therewith a hydrophilic plasticizer which is the reaction production of a polyhydric alcohol and an acid, said body also having hydrophilic textile fibers distributed therethrough, said body providing retention and release of aqueous solutions.
8. The roller of claim 7 in which said plasticizer is triethylene glycol di-caprylate.
9. The roller of claim 7 in which said plasticizer is dimethyl glycol phthalate.
10. The roller of claim 7 in which said plasticizer is methyl glycol oleate.
11. The roller of claim 7 in which said plasticizer comprises approximately 7% to 25% of said body by weight.
12. The roller of claim 11 in which said fibers comprise approximately 10% to 25% of said body by weight.
References Cited in the file of this patent UNITED STATES PATENTS 2,119,491 Rapport May 31, 1938 2,350,350 Gresham June 6, 1944 2,393,953 Bacon Feb. 5, 1946 2,449,058 Coes Sept. 14, 19.48 2,633,456 Vaughan Mar. 31, 1953 2,697,087 Hetzel Dec. 14, 19.54 2,922,776 Wulff et a1. Jan. 26, 1960 2,978,431 Engle Apr. 4, 1961 d Wau-