USRE21575E - Container closure and limino - Google Patents

Description

Sept. 11, 1940. K. TATOR Re. 21,575

CONTAINER CLOSURE AND LINING COMPOSITION Original Filed Sept. 4, 1934 II II vlllnuanllulrunllnnanl fmenibr: Jf ermef/1 72.7fm"

m a? (17mm JZzfarney Reissued Sept. '17, 1940 UNITED STATES CONTAINER CLOSURE AND IJNING- COLIPOSITION Kenneth Tater, Em, Mala, a-ignor to Dewey All!!! M011 am and , North d ala. a corporation of Orlgillal No. 2,134,217, dated October 25, 1938, Se-

rial No. 742.848,

This invention relates generally to the art of container closure and specifically is directed to the production of a superior lining compound. Among the objects of the invention are to provide a method 01' incorporating substantial amounts of fibrous fillers in the compound with out at the same time unduly increasing its viscosity; to prevent substantial hydration of the fibre; and to produce a fibre-reinforced lining 10 compound.

These and other objects will become apparent from the specification and from the drawing in which the single figure represents a greatly enlarged cross-section through a portion of a double seamed can body and end.

It has been the previous experience that organic or mineral fibres (type substances are cellulose and asbestos) cannot be added to a waterdispersed can-lining compound insubstantial go amounts because such fibres hydrate readily and form sluggish viscous quite unsuitable for can lining purposes. For example, a water slurry containing 8% of dry fibre is too still for the purposes ofthis invention. The controlling 1| factor is, of course, the viscosity limits which arerlgidly setbythe nature oftheliningmachinery and the configuration of the can ends used 1! rubber and wood pulp or cotton'fibres are so worked on a rubber mill, the fibre is drawn into the rubber by the apparent process of wetting.

Itismybeliefthattherubberparticleswetthe individual cellulosic fibers and also that this wetting is preferential and persists in the presence 35 of water. In certain cases, notably with news pulp,.the amount of dried fibre which can be carried in may equal the weight 0! the rubber.

Incertain other cases, as when cotton linters or cotton fiock are used, this proportion cannot 40 be obtained without producing a stock which is too short to follow or work on the mill. In such a case I follow the procedure outlined by W. B.

Wescott, U. 8. Patent No. 1,702,225, and beat the fibres to form a slurry, then add latex. and

a precipitate rubber upon the fibres in the manner he has described. when dried. such coated fibres may be milled into a rubber mass over a very wide range of proportions. It asbestos be used, I consider it advantageous but not strictly 50 w -toprecoat thefibres with rubberlatex andinsuchcaseImayutllizetheprocesset forth by G. R. Tucker in U. 8. Patents Nos. 1,907,616 and. 1,907,617.

I have discovered that such high fibre conutentmlxtin'escanbedlspersedundercertain September 4. I934. Application for reissue July (0|. see-a1) 194., Serial No. 347,551

conditions and that the coated (or rubber wetted) fibres do not hydrate in a comparable degree to untreated 'fibres in water. Without regard to the accuracy of my explanation of this V eflect, I note as a fact that I am able to pro- 5 duce a water dispersed lining compound containing one part of fibre to one part oi rubber solids and still have a viscosity which is suitable for lining machine requirements.

I have also discovered that this eifect is not limited to rubber or its analogues but occurs generally whenever a substantially non-hydratable body is used. For example, excellent low viscosity dispersions based on asphalt, parafiln and waxes may alsobe made.

It is widely believed that the dispersion of rubber in water is brought about by the repeated stretching of the rubber mass and the introduction of water between the rubber globules with each extension. It is also stated that the protective colloid serves both to carry in the water and to coat the rubber globules to prevent their re-coalescence. Whether this be true or not, the fact remains that rubber to disperse well in a mixer must originally possess some nerve". The mixture of one part fibre, one part rubber is, however, soft and crumbly and cannot be dispersed with the cheap and commonly useddispersing agents such as kaolin and bentonite. They are unctuous and slippery. Soap dispersing agents also fall. But, I have found that the property of "nerve" need not re- "side in the rubber, but may be introduced as an attribute of the colloid. Substances such as casein, glue, gelatin, karaya, sea moss and the $5 algins attach themselves so firmly to the rubber and have such high self-cohesion that the pulling and stretching of the rubber necessary to produce a dispersion can be brought about.

The seal produced by my compound is illustrated in the figure. a sectional view through a portion of the can body and end after the double seaming operation. The gasket ll, formed from the dispersion, is enfolded in and locked between the can body It and the can end II. The feature of such rubber deposits from water dispersions is the retention in the rubber agsregate of the physical constituents which characterized them in water dispersion, whereas the physical constituents of the aggregates derived from the evaporation of rubher "solutions" are disrupted and materially changed.

As a specific example of my invention, 850 partsofrubberandjfiopartsotnewsprintpulpq l pounding ingredients may be added to the mass which may be viscosity or plasticity factors such asaredisclosedinthepatenttoDeweyand Crocker, No. 1,765,134, or they'may be vulcanizing agents. The addition of such factors has no 18 eifect on the general nature of the dispersion I produce. I i

In the same general manner, I am able to produce dispersions of wool, cattle hair. shoddy, or asbestos. As I have previously stated. my inven- 20 tion is not limited to coating the fibres with rubber, or like substancesalone, but asphalt, waxes and paraflln may be used in the manner specified. In the case of was, the addition of an ethanol amine may be found helpful-and in all cases a 25 disinfectant or preservative aids when the dispersions are to be stored.

The above formula is, accordingly, given for illustrative purposes only and no limitation is intended by reason of the materials given or the 80 proportions stated therein. Those familiar with the art will recognize that the proportion of fibre which can be added may vary through wide limits and that my invention u general utility whenever it is desired to produce a dispersion con- 8! taining substantial quantities of fibre.

I claim:

1. A container closure having its joint portion provided with a sealing material deposited thereon comprising the dried residue of a water dispersion of unhydrated fibres normally hydratable but which fibres at the time of incorporation in said water dispersion are protected against hydration by a water impervious coating of a substance hydratable to a low degree.

2. A container closure having its joint portion provided with a sealing material deposited thereon comprising the dried residue of a water sion of unhydrated fibrous particles coated with a water impervious coating of rubber, the rubber and fibrous particles being present in substantially equal amounts by weight.

3. Themethodofformingacontainerclosure for hermetic sealing, which consists in depositing upon the joint portion of said closures sealing material comprising a water dispersion of unhydrated fibres normally hydratable but which fibres at the time'of'incorporation in said water dispersion are protected against hydration by a water imperviouscoatingofasubstancehydratabletoa lowdegree,anddryingsaiddepositedmaterial.

4. The process of preparing a container closure 10 for hermetic sealing, which consists in coating unhydrated fibre particles with a water impervious coating of rubber, forming a water dispersion of said rubber coated fibres, depositing said water dispersion on the ioint portions of said closure, 5 and drying said deposited dispersion.

5. The process of producing sealing gaskets on container closures, which comprises thoroughly milling together rubber and fibrous material in a dry state to produce an intimate homogeneous mass in which the particles of fibrous material are provided with water impervious coatings of rubher, mixing a dispersing agent with said mass, forming a water dispersion of said mass of fiuid consistency, depositing the dispersion on the sealing portions of said closures, and drying the deposited dispersion.

6. The process of forming sealing gaskets on container closures which consists in milling together natural rubber and dry fibrous material in 80 substantially equal proportions by weight to form a homogeneous mass in which the particles of fibrous material are provided with water impervious coatings of rubber, forming a water dispersion of said mass, applying said dispersion to the closure parts to be sealed, and drying said deposited dispersion to leave a solid gasket on said surface.

7. The method of forming sealing gaskets on container closures, which consists in milling together dryrubber and dry fibre'to form a homogeneous mass in which the particles of fibrous material are provided with water impervious coatings of rubber, dispersing said mass in the presence of water and a hydrophilic colloid having 5 high cohesive strength, depositing said dispersion upon the surfacesoi'saidclosurestobesealed, and drying said deposited dispersion to leave a solid gasket on said surface.

KENNETH Tfi'lDR.

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