US1668349A - Paper article and method of manufacture - Google Patents

Description

May 1, 1928. 1,668,349

- E. G. BAUM PAPER ARTICLE AND METHOD OF MANUFACTURE Filed March 22. 1926 Patented May 1, 1928.

UNITED STATES PATENT OFFICE.

EWALD G. BAUM,

OF NATICK, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS,

IORATION OF MASSACHUSETTS.

PAPER ARTICLE AND METHOD OF MANUFACTURE.

Application filed March 22, 1926. Serial No. 96,503.

This invention relates to articles of cellulosic material and a method of manufacture, more especially of such articles formed up from paper sheets, as, for example, certain forms of bottle caps or'closures. More particularly it relates to such articles and their formation where resistance to deformation in the presence of moisture is desirable or necessary.

It has been found that when such articles are formed. by pressing sheets of paper out of their normally flat condition there is a strong tendency for such articles to flatten out somewhat under the action of moisture, even though the sheet material be quite thoroughly treated with waterproofing material, and where milk bottle caps are so made, these caps being provided with pouring lip housing portions, as shown, for example, in my-Reissue Patent No. 15,491 dated November 21, 1922, for bottle caps, this tendency, if not counteracted, causes the marginal portions thereof to flare so that they do not properly engage the bottle. The caps then do not hold to the bOl'r' tles with suflicient tenacity and the contents are not always completely sealed.

By the method of the however, the structure 0 the paper is so so modified over at least those portions where flattening would be likely to be detrimental, that such flattening tendency is quite effectually prevented. In general the method comprises .a preliminary treatment of the paper by which the cellulosic fibers are swelled and softened and by which the de sired waterproofing compounds are incorporated therein prior to the forming of the aper into the article, and after this preiminary treatment the subjection of the material, preferably in the process of formation, to such heavy pressure, at least over that portion or portions where flattening is to be prevented, that the fibers are compacted together and the fibers of successive overlapping layers interfelted so as to form with the waterproofing agent a dense, horn like, translucent structure inthe desired sha e quite different from the structure of tiie paper sheet before being subjected to this pressure.

Present invention,

For a more complete understanding of this invention reference may be had to the accompanying drawings showing the application of the method to a form of a milk bottle cap somewhat like that shown in my reissued patent hereinbefore referred to. In these drawings,

Figure 1 is a plan of a blank from which the cap is to be formed.

Figures 2, 3, 4 and 5 are detail sections showing successive positions of the dies relative to each other and to the blank as it is being formed into a cap.

Figures 6 and 7 are elevation and plan Views, respectively, of a partially formed cap corresponding to that illustrated in Figure 4.

Figure 8 is a detail section on line 8-8 of Fi ure 6; I

igure 9 is a side elevation of a fully formed cap.

Figure 10 is a detail section on line 1010 of Figure 9.

The paper stock employed for this process should have high absorptive qualities and should be of uniform thickness and of a strength as near as possible the same across the sheet as in its lengthwise direction. The paper is blanked out to the form required to make up the article and either before or after the blanking operation, is subjected to the following steps.

First, it is treated with water which it should be capable of absorbing freely, the water being applied to the paper under such conditions of time pressure and temperature as are found most suitable with the particular stock being employed. The warmer the water the easier the paper absorbs it under ordinary conditions. If the water is warm the pressure or time of treatment or both may be reduced, or the treatment may be prolonged under lower pressure or temperature conditions or both. The treatment should be sufiiciently thorou 11, however, to cause the cellulosic fibers 0% the paper to swell and soften to a material extent. The moistened paper should be allowed to stand a suflicienttime so that the moisture becomes uniformly spread' through its tex 'ture, Ordinarily but aiew minutes is necessary for this, the time necessary depending largely on the particular paper stock being employed and somewhat also on the moistening methods which may have been used. The paper should then be passed through a waterproofing compound preferably at an elevated temperature. The compound which has been found most suitable in practice comprises waxes, such, for example, as paraflin preferably with the addition of a small amount of hardening wax such as carnauba or Montan wax. The particular composition of the wax may be varied to suit the product and also somewhat to suit the stock being treated. When the moistened and swollen paper passes into this bath of wax which should be at a temperature above 212 F., as for example from approximately 235 F. to 240 F., a portion of the water in the material is converted into steam and escapes and as the paper passes out from the melted wax the condensation of steam which may remain in the paper draws in the melted wax so as to impregnate its fibrous structure without destroying its tensile strength, and to fill the intercellular spaces of the paper without however causing the fibers to be shrunk and contracted to their substantially dry condition.

After the sheet material is treated with the wax it is preferable to permit it to stand for some hours, say 24 or more, in a closed container, the material then cooling and seasoning or tempering. When removed from these containers it is in condition for the forming operation. In the case of the formation of the bottle cap of the type hereinbefore described the operations to be carried out are shown somewhat diagrammatically in the drawings. A waxed and tempered blank 1 is placed upon the die member 10, shown in Figures 2 to 5, and the die member 11 is brought down on its central portion as at 2, the blank being thus held in position for the further forming operations. Next the die member 12 is brought down against the upper face of the blank, pressing it against the outer portion 13 of the die member 10. Next the die member 14 is moved upwardly, as shown in Figure 4, forming up the upstanding wall 15 which is to engage the inner wall of the milk bottle above the usual annular ledge therein on which the usual disk of cardboard is placed.

Next the outer die member 16 is brought downwardlyto form the outer margin of the blank into the downwardly extending portion 17, shown best in Figure 9, which bears against the outer face of the bottle pouring lip. The pressure exerted on the material by these dies is very considerable,

being on the order of from 6,000 to 10,000

pounds per square inch for waxed paper approximately .028 inch thick or .022 inch thick before being softened and waxed, and the clearances between the die members 12, 14 and 16 are so proportioned that substantially this pressure is exerted on the material therebetween when the cap is being formed.

It will be noted that since the maximum diameter of the finished cap is very inuch smaller than that of the blank from which it is formed, the material in the inner upstanding and in the outer downwardl extending portions 15 and 17, respectively, must be gathered together in overlapping layers, and where the material is treated as hcreinbefore described prior to the forming operations this heavy pressure causes these overlapping portions -to be pressed together resulting in more or less interfelting of the fibers in the contacting layers and compacting the fibers and the wax into a dense, horn-like structure which is highly resistant to the action of moisture.

Where articles of paper are formed up by pressing from. flat sheet material there is a strong tendency for overlapping layers to separate somewhat so that the material tends to flatten after formation, this tendency being particularly noticeable when the articles are subjected to moisture conditions. If this should be permitted in the case of a bottle cap of the type shown, it would result in the outer pouring lip housin wall flaring so that its lower edge woui d not properly engage the outer side of the bottle and would also result in the inner wall engaging the inner wall of the bottle drawing away from close contact with the bottle so that the sealing qualities of'the cap would be very greatly lmpaired and its removal from the bottle would be rendered too easy for security. By the treatment herein outlined, however, this pouring lip housing,

which is of general channel shape in section, is maintained in proper condition with the opposite walls thereof in the form in which they are produced by the dieing operation. It has been found in practice that such a cap may be subjectedto water for an indefinite time without showing any tendency for flattening of the cap or flaring of these walls to occur. Preferably, though not necessarily, the upper portion of the pouring lip housing has radial corrugations since this construction produces added resiliency to the pouring lip housing portion so that it may be pressed over the pouring lip and tightly engage it on opposite sides. Preferably also the heavy pressure is applied to substantially the entire aieaof the cap ineluding its central bore-covering portion,

the upstanding wall portions 20 which are formed to engage the inner wall of the bottle beneath the usual disk-receiving annular ledge, andthe annular portion 21 which is formed to seat on the upper face of this the pressure completely formed, while Figure 10 illus-. 'trates in section the condition of this portion of the cap after it has been subjected to the heavy pressure so that it has been reduced to a substantially homogeneous, translucent, horn-like structure of substantially uniform thickness with the fibrous material of the overlapping layers felted together. This horn-like structure of the material can not be produced by the use of a water treatment alone, apparently the wax or its equivalent waterproofing material being necessary to produce the. interfelting of the fibers under to which they are subjected according to this method. This material also serves an Important function in the formation of the wall portions 15 and 17 of the cap in that it acts as a lubricant betweenthe die members and the sheet material and prevents these members from tearing the material due to their severe rubbing effect thereon during the forming operation. It also acts as a binder for the fibers and the layers'in the finished product.

Having thus described this invention it will be evident that various modifications and changes might be made therein without departing from its spirit or scope as defined by the appended claims.

I claim:

1. An article formed up from sheet cellulosic material containing a waterproofing agent and having portions of the sheet in folded overlapping relation, said portions being compressed to substantially uniform thickness and presenting a dense horn-like structure resistant to opening up when subjected to moisture.

-2. An article comprising sheet cellulosic material having portions thereof in overlapping relation, said portions presenting a dense, horny, mterfelted structure resistant to separation of the overlapping portions when subjected to moisture.

3. An article formed up from waxed sheet cellulosic material and having a portion comprising folded layers of such sheet material interfelted and compressed to a translucent, horn-like condition.

4. An article formed up from waxed sheet cellulosiqmaterial and having a portion com; prising folded layers of such sheet, such portion being formed into a dense, horny structure retaining its folded condition indefinitely when subjected to moisture.

7 and 8 is illustrated the 5. An article formed up from a sheet of waxed paper and having a portion comprising folded layers of such sheet, said portion belng compressed to form a dense, horny structure retainin its folded condition indefinitely when su jected to moisture.

6. A milk bottle cap having a bore-covering portion terminating in an upstanding port-ion enga cable with the inner wall of a milk bottle elow the usual disk-receiving annular ledge therein, a portion formed to overlie said ledge, a portion upstanding from said ledge-engaging portion to engage the inner wall of the bottle above said ledge, and a marginal downwardly turned portion engageable with the outer wall of the bottle,

said upstanding and downwardly turned.

portions presenting dense structure resistant to deformation when subjected to moisture. v7. A milk bottle cap of waxed paper having a bore-coverlng portion terminating in an upstanding portion engageable with the inner wall of a milk bottlebelow the usual disk-receiving annular led 'e therein, a portion formed to overlie sai ledge, a portion upstanding from said ledge-engagin portion to engage the inner wall of the ottle above said ledge, and a marginal downwardly turned portion engageable with the Outer wall of the bottle, said upstanding and downturned portions comprising layers of the waxed paper folded together and compacted to a dense, translucent, horn-likecondition resistant to unfolding in the presence of moisture.

8. A bottle cap having a pouring lip housing engageable with opposite sides of the bottle wall, the wall-engaging portions comprising folded layers of interfelting sheet horn-like material.

10. The step in the process of forming a waxed blank of moistened cellulosic sheet material into an article having portions of the sheet in folded overlapping relation which comprises subjecting said portions to pressure sufiiciently heavy to compact them to substantially homogeneous rigid horn-like structure of substantially uniform thickness. f 11. The method which comprises swelling and softening a blank of fibrous sheet material, incorporating wax therein, and then forming an article from the blank thus treated under pressure sulficiently heavy to comact the material together into a dense,

orny condition.

.12. The method which comprises treating a fibrous blank with water, passing the wet blank through a liquid wax heated to a temperature above 212 F. and thereby vap0riz ing a portion of the water from said blank 5 and saturating the blank with the Wax, permitting the blank thus treated to temper, and then forming said blank to the desired EWALD G. BAUM.

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