US 2537785 A
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Jan. 9, 1951 R. D. OPPENHEIM METHOD OF PROTECTING SHOES DURING MANUFACTURE 2 Sheets-Sheet 1 Filed Jan. 6, 1949 INVENTOR. RICHARD I). OPPENHEIM A'TTO/P/VEYS.
1951 R. D. OPPENHEIM 2,537,785
METHOD OF PROTECTING SHOES DURING MANUFACTURE Fild Jan. 6, 1948 2 Sheets-Sheet 2 INVENTOR. RICHARD D. OPPENHEIM WMMMW ATTORNEY Patented Jan. 9, 1951 IVIETHOD F PROTECTING SHOES MANUFACTURE DURING Richard'D. Oppenheim, Woodside, N. Y., assignor to Spraylat Corporation, New York, N. Y., a corporation of New York Application January '6, 1949, Serial No. 69,511
Claims. '-(Cl. 12-; 1 i2) My invention relates to the manufacture of shoes, and has particular reference to a method of removing temporary protective coatings from described in such patents as Patent No. 1324,2151
issued to Edwin E. Newton, and Patent No. 2,049,554 issued to Walter H. Wedger.
The manufacture of shoes according to the aforementioned methods, is, however, subject to several disadvantages. Before the outsole of the shoe may be cemented to the insole, the marginal edge portion of the upper overlyin the insole must be roughened or abraded, and therefore must be first cleared of any protective film. Itis extremely important, however, to protect the ex-- posed outer edge of the upper against soilage due to the sole cement as well as the dyes used on the outsole. The lower edge of the upper, adjacentthe lasting portion must particularly be protected against soilage. It is important, therefore, to re--:
move the film from the marginal area, while retaining it upon the rest of the upper. In order to cleanly strip the film from the finished shoe, no portion of the film should remain between the outsole and the upper.
Due to the elastic nature of the rubber film, it,
is impossible to remove by roughing the unwanted section of film on the marginal edge portion of the upper overlying the insole without:
tearing or otherwise damaging th latex coating on the adjacent portions of the upper.
There have been various methods proposed for removing unwanted portions of the latex protective coverin while retaining the desired protective coating intact and undamaged. The most satisfactorily-proven method up to the present has been the use of a dull, hot knife with which the undesired latex portions are scored off. The marginal area of film may then be stripped off, permitting the shoe to be roughened on this area.-
This process of scoring with a cautery knife is,
however, time-consuming and introduces a new. operation in the shoe manufacturing process. Another method of meeting this problem is sugoeen found undesirable since it is more expedienta 2 gested in the aforementioned Patent No. 2,049,554 and comprises applying the latex composition to the outsole by means of a brush after the outsole has been attached to the last. This method has to apply the latex coating to th outsole before the lasting step is reached.
It is the principal object of my invention therefore, to provide a novel method for removing any desired portion of a temporary protective latex film without interfering with the normal shoe manufacturing process.
Another object of my invention is the provision'of a novel method of roughening the marginal lasting p rtion of the shoe upper without; tearing or otherwise damaging the adjacent protective coating.
Still another object of my invention is the provision of a protective coating for shoes which will;
not readily rupture upon contact with shoemachine parts. I These and other objects of my invention will; be readily apparent in the course of the follow- 1 ing specificationwhen taken in connection with the accompanying drawings, in which: j Fig. 1; is a bottom perspectiv view of ashore, attached to the last, and treated with a lacquer;- coating according to my new method;
Fig. 2 is a fragmentarysection thereoi'taken; alon line 22 of Fig.1; v :f Fig. 3 is a bottom perspective view smilar to} Fig. l but showing the lacquer-treated latex coating removed from the marginal lasting portion of} the upper; and l i a Fig. 4 isa fragmentary section taken along line: 4-45 of Fig.3. 7 j f' The drawings illustrate a cement shoe, by which is meant a shoe to which the outsole is to, be cemented. The shce comprises an upper I which has been covered by an outer film Of protective latex or latex composition i2, as previ-'- ously described. The entire upper H may be covered with the latex film !2. before lasting. The upper i l is then attached to a conventional last it in the usual manner. To the latex film !2 which covers the marginal overlapping lasting portion M of the upper, an outercoating of film-forming lacquer I3 is ap-, plied. The said-lacquer I3 maybe applied with-1 a brush or in any other suitable manner. The
marginal overlapping last ng portion M of-the upper to which the lacquer is app'ied, is that 1 portion of the upper II which overlies the top I surface of the last it, and which must be roughened before the sole is cemented thereto. The
lacquer is also applied to the adjacent areas of the upper, for reasons which will be presently I set forth.
The lacquer which has low elongation, high tensile strength, and good adhesion, bonds to the latex film and forms with said latex film a single bonded, tough film which is rigid enough to be severed and removed by means of a rotating roughing wheel. Figs. 1 and 2 show the lacquer film [3 applied to the latex coating I2 on the marginal lasting portion of the upper II and also on the adjacent areas on the sides of said upper l I.
After the lacquer has dried sufficiently to form a tough and rigid bonded film I3 on the latex coating l2, lacquer film l3 and its bonded latex film l2 are abraded from the marginal overlapping lasting portion M of the upper II. The
abrading may be done by means of a conventional rotating roughing wheel, and thus the unwanted area of latex film may be removed and the marginal lasting portion M of the upper roughened in the same operation.
Figs. 3 and 4 show the lasted upper ll after the bonded film of latex l2 and lacquer IS on the marginal lasting portion has been removed by the roughing wheel, leaving the upper ll exposed. Since the adjacent areas are also covered with the lacquer, the marginal portion of latex and lacquer may be cleanly severed without tearing or rupturing the adjacent areas of latex.
The lacquer film I3 has no permanent deleterious effect upon the rubber latex film l2, and does not in any way interfere with its removal after the shoe is finished.
After the marginal portion has been roughened, the adjacent areas remain covered with lacquer, which forms a hard, smooth, tough outer coating on the latex film, preventing it from rupturing from friction of machine parts. Because of this tough outer coating, a machine part, such as an edge trimmer shield may be slid along the lower portion of the upper or otherwise brought into contact therewith, Without damaging the coating or impairing its protective function.
In the drawings, the lacquer-covered latex is shown abraded and removed from the entire area of the upper overlapping the top of the last. If desired, however, the latex on the heel portion of this area may be left on the upper, since the heel is not cemented to the shoe. Instead of abrading the latex off the upper in this area, it is merely necessary to abrade a narrow line between the marginal portion and the adjacent area. This may be done by the use of a small emery wheel, or in any other desired manner. The heel may thus be attached directly over the latex and lacquer film in the respective marginal portion, and when the shoe is finished, the protective latex may be cleanly stripped from the remainder of the upper, because of the abraded line.
The method described in the next preceding paragraph is particularly useful in the manufacture of welt shoes and the combination welt and cement shoes, in which it is only necessary to remove the protective film from a small area between the upper and outsole which is to be cemented. Thus the latex covering on the welt portion of the overlapping upper may be severed or cut from the remainng portion of the latex covering, by making a narrow line between the two portions with an emery wheel. The sole may be attached over the separated portion of latex on the overlapping upper and the remaining portion of latex covering on the upper cleanly stripped off, after the shoe is finished.
The aforementioned lacquer which is applied 'to the protective latex portion may be formulated from any of the film-forming resins such as ethyl cellulose, cellulose acetate, cellulose nitrate, or polyvinyl resins. Such resins may be used alone, or may be combined with plasticizers and natural or synthetic resins.
I have found that the best results for eflicient shoe manufacturing may be obtained by the use of a lacquer which is easy to apply and fastdrying, and which has good film strength as well as good adhesion. By adding rapid-drying sol vents to the lacquer, the lacquer can be applied to the upper at any time after the lasting operation without interfering with the normal plant operation by requiring operations to be suspended While the lacquer is drying. I have found that best results may be obtained by using the compound made according to the following formula:
Parts by weight Ethyl cellulose (Dow Chemical Standard 100 cp.) 10 Toluol Ethyl alcohol 20 Toluol or other similar rubber solvent is used in the lacquer primarily as a solvent for the ethyl cellulose, but also for its effect upon the latex coating. The toluol combines with the latex film which is covered by the lacquer, reducing the elastic qualities of the latex. The latex coating in the presence of toluol, swells and becomes weakened, having a low elongation. Thus the weakened layer of latex and its bonded layer of lacquer offer a surface which may be easily abraded. After a relatively short period, the toluol will evaporate leaving the protective latex coating with its elasticity unaffected. The latex coating may then be conveniently peeled from the upper.
The use of fast-drying solvents such as ethyl alcohol and toluol provide reagents of such rapid-drying properties, that within fifteen minutes after application, the lacquer and its bonded latex may be removed from the marginal area of the upper by roughing. Thus the compound may be applied immediately after the bottom ironing of the marginal area without loss of appreciable time of manufacture.
Should the manufacturing process be such that drying time is not a critical factor, it is possible to use a water solution or a water dispersion of film-forming materials, such as polyvinyl alcohol, polyvinyl butyral, methyl cellulose, and casein. These materials possess all of the aforementioned desired qualities, except that they are relatively slow-drying.
It is obvious that numerous alterations, additions and omissions may be made in my invention without departing from the spirit and scope thereof. For example, the lacquer may be applied to any desired portion of the latex covering on the upper, instead of the marginal lasting portion.
1. A method of protecting shoes during manufacture which comprises applying a latex coating to a shoe upper, assembling said shoe upon a last, applying to portions of said latex covering a film-forming lacquer which will bond to said latex coating to form a rigid covering on -25 the shoe upper, then abrading selected portions of said rigid covering from the shoe upper while leaving the remainder of the latex coating unafiectecl, proceeding with the lasting operation, and subsequently stripping the remainder of the latex coating from the upper.
2. A method of protecting shoes during manufacture which comp-rises applying a latex coating to a shoe upper, assembling said shoe upper on a last, applying to the marginal edge portion of the upper a film-forming lacquer which will bond to said latex coating to form a rigid covering on said marginal edge portion, then abrading the rigid covering from said marginal edge portion while leaving the coating on the remainder of the upper unaffected, attaching the outsole of the shoe over the marginal edge portion of the upper, and subsequently stripping the remaining latex covering from the shoe upper.
3. A method of protecting shoes during manufacture which comprises applying a latex coating to a shoe upper, assembling said shoe upper on a last, applying to the marginal edge portion of the lasted upper a film-forming lacquer which is made of a resin and a rubber solvent and which will combine with the latex coating to form a rigid, non-elastic outer coating on said marginal edge portion, then abrading the rigid outer coating from said marginal edge portion while leaving the coating onthe remainder of the upper unaffected, and simultaneousl roughening the marginal edge portion of the shoe upper, attaching the outsole of the shoe over the roughened portion of the upper, and subsequently stripping the remaining latex covering from the shoe upper.
4. A method of protecting shoes during manufacture which comprises applying a latex coating over the entire surface of a shoe upper, assembling said shoe upper on a last, applying to the marginal edge portion of the lasted upper a film-forming lacquer composed of a film-forming resin, a rub-her solvent, and a rapid drying agent, allowing said lacquer to dry sufliciently to combine with. said latex coating and to form a non-elastic rigid film therewith, abrading said rigid film from the marginal edge portion of the shoe upper with a roughening wheel and simultaneously roughening the marginal edge portion of the shoe upper while leaving the coating on the remainder of the shoe upper unaffected, attaching the outsole of the shoe over the roughened portion of the upper, and subsequently stripping the remaining latex covering from the shoe upper.
5. A method according to claim 4 in which the areas of the shoe upper adjacent the marginal edge portion are also coated with the filmforming lacquer, and in which said lacquer is left upon the latex covering until the latex covering is stripped from the upper.
RICHARD D. OPPENI-IEIM.
DES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,339,462 Lionne May 11, 1920 2,031,674 Schneider et al. Feb. 25, 1936