US 3214193 A
Description (OCR text may contain errors)
United States Patent 3,214,193 BOOK Lawrence A. Monroe, Evanston, llL, assignor to R. R. Donnelley & Sons Company, a corporation of Delaware No Drawing. Filed May 20, 1963, Ser. No. 281,743 4 Claims. (Cl. 28121) This invention relates to a book construction employing in combination with the usual assembly of paper sheets a combination of adhesives for binding the paper sheets to the book.
In making certain types of books, particularly those using a patent binding, it is customary to adhere the back edges of the paper sheets making up the book with an adhesive which may have incorporated therewith a loosely woven fabric in order to give strength at the back of the book. Customarily, this adhesive has been an animal protein glue containing water. This adhesive has customarily contained glycerine which serves primarily as a plasticizer or humectant for keeping the glue flexible.
This type of prior book construction has not been completely satisfactory, as the adhesive tends to dry out and become brittle so that the book can be cracked at the back if it is opened up to too great a degree. Furthermore, in order to apply animal protein glue to books, it has been customary to liquefy the glue by adding water and by heating. It has been customary to limit the heating to an upper temperature limit of 140 F. to avoid the denaturation of the proteins which is prone to change their chemical nature when wet above that temperature, causing loss of their ability to serve as adhesives. Bookbinders customarily apply glue to books wit-h mechanized glue pots which cannot operate well if the viscosity of the contained glue is much in excess of 10,000 centipoises. Accordingly, it is usual to add water in the pots to reduce the Working viscosity to this level, using mixtures of glue, glycerine, and water whose water content amounts to 30 or 40 or more percent of the total mixture.
When paper covers or liners are applied to such wet glues the free water of the glue tends to diffuse into the paper, softening it, so that further processing and handling of the book, such as conveying, storing, trimming. wrapping, bundling, and shipping may mar or destroy the paper cover or liner, if done within eight to sixteen hours after application of the glue.
It is known that when water is added to perfectly dry animal protein glue, the first 20 or 21 percent of water added to the protein becomes bound to the protein, much as Water of crystallization is bound to certain chemical compounds. It might be thought that a glue of such low water content could be used with customary glycerine additions in bookbinding, as the absence of free water from such glues would reduce or eliminate the softening of paper covers and liners previously mentioned. However, in order to obtain the proper fluidity in the glue pot which is a part of every binding machine for producing books of this type, it is necessary to heat such an adhesive of low water content to as much as 180 F. or more. At these temperatures the animal glue tends to deteriorate and lose its adhesive characteristic, so that the glue pot must be frequently emptied and refilled with fresh glue.
One of the features of the present invention is to provide an improved book construction that avoids the above difiiculties.
Other features and advantages of the invention will be apparent from the following description of certain embodiments thereof.
In the present invention the book comprises an assemice bly of paper sheets having the back edges aligned for binding and with the sheets being bound at the aligned back edges with an adhesive that is in at least two layers. The first adhesive layer is a conventional book binding adhesive including the usual animal gelatin-glycerinewater combination.
On this first adhesive layer which is applied directly to the back edges of the aligned paper sheets there is provided a second adhesive layer of a specific type. This second layer comprises animal gelatin containing approximately 20% bound moisture, as contrasted to free and separate moisture; about 50-90% by weight of glycerine based on the total Weight of gelatin plus water. A coumarone-indene resin having a ball and ring softening temperature of about 25-55 C. comprises about l020% by weight of the total weight of the gelatin plus Water plus glycerine. This second adhesive is prepared by adding the coumarone-indene resin in molten form to the other ingredients at a temperature of about F. Adhered to this second adhesive layer is a book cover to complete the book.
In a book having the characteristics set out in the preceding paragraph the moisture in the first adhesive layer is retained because the second adhesive layer prevents passage of the moisture therethrough. This means that the adhesive combination at the back of the book retains its moisture and remains flexible for an extremely long period of time. It also means that the cover can be water sensitive and will not be damaged by the water of the first adhesive layer as the second adhesive layer functions as a moisture barrier. In addition, the second adhesive layer (which does not readily bond directly to paper) binds the paper sheets much better than when used alone as the first layer diffuses into the adjacent edges of the paper to form a firm bond therewith so that the second layer, in turn, is bonded firmly to the first layer.
' A very important advantage of the book of this invention is that the book can now be trimmed within a few minutes (often within three minutes) after the second adhesive layer and the cover are installed instead of the 8 16 hours required with a conventional adhesive binding. Another very important result of this invention is that the glue pot containing the second adhesive now need only be heated to about 150 F. instead of F, This means that there is less heat degradation of the animal protein and there is therefore less wasting of adhesive. In the conventional book binding machine the adhesive must be maintained at approximately 10,000 centipoises viscosity in the glue pot in order to operate properly.
Example 1 In one example of the invention the book pages are arranged in the conventional manner and these aligned rear edges were coated with a first adhesive layer made up of 27.8 parts gelatin, 26.0 parts glycerine and 46.2 parts water. Two-thirds of the gelatin had a gel strength of 320 as measured by the Bloom gel strength test while one-third had a gel strength of 185. All parts and percentages herein are by weight.
For the second adhesive layer the adhesive was made up of 44.3 parts gelatin, 34.4 parts glycerine, 21.3 parts water and 10 parts coumarone-indene resin R-l9 (made by The Neville Co.). The coumarone-indene resin of this example had a softening point at the ball and ring test of about 55 C. (molecular weight about 500 to 600).
The first adhesive was applied to the pages while heated to the proper fluidity. Then, the second adhesive was applied over the first adhesive. Finally, a flexible conventional binding was applied over the second adhesive. The pages of the book were immediately trimmed.
Example 2 In a second example the first adhesive was the same as described in Example 1. The second adhesive was the same as described in Example 1 except here an additional parts of coumarone-indene resin R-29 (made by The Neville Co.) was added. This latter resin has a softening point of about 25 C., measured as set out above, and a molecular weight of about 500 to 600.
Example 3 In this example the first adhesive was the same as that of Example 1 while the second adhesive used the same amounts of ingredients as set out in Example 1, but half the gelatin had a gel strength of 400450 and the other half 185 while two-thirds of the coumarone-indene resin was R-19 and one-third was R29.
Example 4 In this example the second adhesive contained 54 parts gelatin, 26 parts glycerine, 20 parts water and 15.2 parts coumarone-indene resin. In this example the glycerine and the resin were as described in the preceding example.
In producing the books of the above examples, the rear edges of the stacked sheets of paper were roughened in the conventional manner in order to increase the adhesive strength. Also, each adhesive was heated in its glue pot until the viscosity was about 10,000 centipoises.
Conventional glue or gelatin humectants or plasticizers other than glycerine may be used, for instance, various glycols, sorbitol and the like.
Having described my invention as related to the embodiments set out herein, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.
1. In a book including an assembly of paper sheets having the back edges aligned and a book cover, an adhesive material combination in the space between said edges and said cover, comprising: a first conventional book binding adhesive layer including the usual animal gelatin-glycerine-water combination adhesive; and a second adhesive layer over said first layer comprising animal gelatin containing about 20% moisture, about -90% by weight of said gelatin plus water of glycerine and about 10-20% by weight of said gelatin plus water plus glycerine of coumarone-indene resin having a ball and ring softening temperature of about 25-55 C., said book cover being adhered to said second adhesive layer.
2. The book of claim 1 wherein said cover is water sensitive but is protected from the water of said first adhesive layer by the presence of said second adhesive layer.
3. The book of claim 1 wherein said resin has a softening temperature of about 25 C.
4. The book of claim 1 wherein said resin has a softening temperature of about C.
References Cited by the Examiner UNITED STATES PATENTS 1,879,757 9/32 Kusch 111 2,277,265 3/42 Zahniser 281-21 2,394,440 2/46 Gordon 26027 2,463,148 3/49 Caesar 2606 2,512,418 6/50 Cornwell 2606 2,523,860 9/50 Budden 28121 2,657,189 10/53 Pinkney 281-21 2,673,845 3/54 Stevens 26027 JEROME SCHNALL, Primary Examiner.
LAWRENCE CHARLES, Examiner.