US2676745A - Shipping case - Google Patents

Description

April 27, 1954 w. GEISLER 2,676,745

SHIPPING CASE Filed Sept. 12, 1949 SOLUTION OF LATEX AND SODIUM SILICATE INVENTOR WILLIAM GEISLER ATTORNEYS Patented Apr. 27, 1954 William Geisler, Tenafly, N. J assignor to Wilbro Corporation, New York, N. Y., a corporation of New York Application September 12, 1949, Serial No. 115,310

This invention relates to shipping cases or cartons such as now almost universally employed for the Shipping of cans, bottles, packaged goods" Such cases or cartons and other commodities. are usually formed from a Single blank of double-faced corrugated paper which is cut and scored to provide four connected side walls with integral flaps to be folded over to form the ends of the carton when erected and packed. Such cartons, when kept dry and properly handled, are quite satisfactory even for heavy loads such as cans of paint and the like, but when the paper absorbs moisture, either from getting wet or in storage in a humid atmosphere, the paper is considerably weakened and is apt to give way, particularly at the score lines where the edges of the can tend to cut through the softened paper.

The object of the invention is to provide a a carton of this standard type wherein the carton is strengthened at the fold lines and is also at the same time rendered resistant to the absorption of water, so that the carton maintains its normal strength under conditions which heretofore have caused the carton to weaken in the manner I have described.

The carton may be strengthened by the method herein described at the fold lines only or throughout the entire surface of one or both faces of the blank. In protecting the score lines only of the carton a solution which serves to toughen the paper is applied to the inner surface of the corrugated board at the score lines.

In the accompanying drawing I have illustrated a carton blank of conventional configuration with its score lines treated in accordance with my invention, and in the legend on the drawing I have recited the ingredients of the applied solution.

The principal ingredient of the preferred toughening solution is latex in the form ofa water emulsion having the proportions of approximately 6()% latex and 40% water. To this is added a water dispersion of clay such as commonly used as a filler in the manufacture of molded rubber articles, the solid content of the dispersion being about 60%. To the mixture of latex and clay there is added a sodium silicate solution which may also have a solid content of approximately 60%. The latex emulsion constitutes about 60% of the toughening solution with the clay dispersion constituting 20% and the sodium silicate solution 15%. The remaining is made up of sulfur about 3%, a, suitable wetting agent, for example, sodium polyacrylic acid, about 1% and a suitable accelera- 2 Claims. (Cl. 22916) tor, for example, a mixture of tetramethyl thiurium disulfide and benzothiosol disulfide. The ingredients are mixed together at room temperature and with the water content above stated, have sufficient fluidity to be applied to the surface of the carton blank by a roll coater of ordinary construction having an applying roller of the desired pattern. The solution may be made thinner for spraying or more concentrated, if desired.

The proportions of the ingredients above speci fied are not critical. Generally speaking, the toughness of the coating, that is, its resistance to puncture and abrasion, is increased by adding to the percentage of latex. The chief function of the sodium silicate is to increase the stiffness of the treated board while the clay serves to give body to the coating which remains on the surface of the carton. However, even where the board itself has ample stiffness and it is desired merely to toughen the board against puncture and abrasion, the sodium silicate is preferably not omitted altogether, as it apparently hardens the coating as well as stiffens the board.-

This compound, when applied to the surface of the board along the score lines in stripes one inch wide in an amount of, say, one pound of solution to square feet of surface, will, after drying, render the board much less water-absorbent in the treated portions than in the other portions, and will also toughen and stifien the board so that its resistance to puncture is greatly increased and its capacity to support a stacking load, particularly when the untreated portions of the board are softened by water absorption, is also greatly increased.

The solution may be applied to the finished blank at the same time that the blank is cut and scored, and may be readily heated to dry and set the solution as the cut and scored blanks are delivered to the stacking mechanism.

The solution may be applied to the entire'surface of the corrugated board on one or both sides after the board is finished, or the solution may be applied to the surface of the paper sheet from which the facings of the corrugated board are made before the board is formed. In either case the board should be heated to vulcanizing temperature after the solution is applied, which may be readily accomplished by feeding the coated sheet, either the paper sheet or the corrugated board, as the case may be, through a conventional heater or the kind employed for vulcanizing rubber solutions applied to textile fabrics.

3 4 Iclaim: References Cited in the file of this patent 1. As a new article of manufacture, a paper carton having portions of its inner surface UNITED TE PATENTS treated with a toughening solution containing Number Name Date latex and sodlum slhcate. 393,899 Haines Dec. 4, 1888 2. A paper carton composed in whole or in part of a sheet of paper board having fold lines f jazi Deventer formed in the board, said fold lines being treated 2,259,035 Gillican Oct. 14, 1941 232:? a solution contammg latex and sodium 5111- 10 2,350,161 Gloor May 30 1944

Claims (1)

1. AS A NEW ARTICLE OF MANUFACTURE, A PAPER CARTON HAVING PORTIONS OF ITS INNER SURFACE TREATED HAVING WITH A TOUGHENING SOLUTION CONTAINING LATEX AND SODIUM SLICATE.

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