US2347618A - Container closure and lining composition - Google Patents

Description

April 25, 1944. O'R 2,347,618

CONTAINER CLOSURE AND LINING COMPOSITION 1 Filed July 25, 1940 INVENTOR KENNETH TATOR ATToRNEY.

Patented Apr. 25, 1944 CONTAINER CLOSURE AND LINING COMPOSITION Kenneth Tater, Egypt, Mass, assignor to Dewey and Almy bridge, Mass. a

Chemical Company, North Camcorporation of Massachusetts Application July 25, 1940, Serial No. 347,541 In Canada June 1'1, 1935 6 Claims.

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 of incorporating substantial amounts of fibrous fillers in the compound without at the same time unduly increasing its viscosity; to prevent substantial hydration of the fibre; and to produce a fibre-reinforced linin compound.

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

The present application is a continuation-inpartof my divisional application, Serial No. 196,-

800, filed March'l8, 1938, which application contains subject matter divided from my Patent No. 2,134,217, patented October 25, 1938. My patent contains claims covering the process of preparing water-resistant sealing gaskets on container closures and the resulting article of manufacture, while the claims of the present application are directed to the novel water-resistant compound and the process of manufacturing. the same.

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 in substantial amounts because such fibres hydrate readily and form sluggish viscous masses quite unsuitable for can lining purposes. For example, a water slurry containing 8% of dry fibre is too stifi for the purposes of this invention. The controlling factor is, of course, the viscosity limits which arerigidly set by the nature of the lining machinery and the configuration of the can ends used.

If rubber and wood pulp or cotton fibres are worked on a rubber mill, the fibre is drawn into the rubber by the apparent process of wetting.

It is my belief that the rubber particles wet the individual cellulosic fibres and also that this wetting is preferential and persists in the presence of water. In certain cases, notably with news ried in may equal the weight of the rubber. In

the amount of dried fibre which can be car-- .tective colloid serves cipitate 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. If asbestos be used, I consider it advantageous but not strictly necessary to precoat the fibres with rubber latex and in such case I may utilize the process set forth by G. R. Tucker in U.'S. PatentsNos. 1,907,616 and 1,907,611.

I have discovered that such high fibre content mixtures can be dispersed under certain 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 effect, I note as a fact that I am able to produce a water dispersed lining compound containing one part of fibre to one part of rubber solids and still have a viscosity which is suitable for lining machine requirements.

' I have also discovered that this efiect 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, parafiin and waxes may also be 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 proboth 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 used dispersing agents such as kaolin and bentonite. They are unctuous and slippery. Soap dispersing agents also fail; property of nerve need not reside in the rubher, but may be introduced as an attribute of the colloid. Substances such as casein, glue, gelatin, karaya, sea moss and the algins attach themselves so firmly to the rubber and have such high elfcohesion that the pulling and stretchingof the rubber necessary to produce a dispersion can be brought about;

The seal produced But, I have found that the.

by my compound is i1lus-' trated in the figure, a sectional view through a into a Baker-Perkins mixer and worked with 100- parts of casein mixed with 150 parts of ammonia water (28%NH3). Additional water to the amount of 1500 parts is run into the mixer bit by bit as the process continues. The mixing is continued until the rubber is "thoroughly dispersed and a smooth paste is formed. Compounding ingredients may -be added to the mass which may be viscosity or plasticity factors such as are disclosed in the patent to Dewey and Crocker, No. 1,765,134, or they may be vulcanizing agents. The addition of such factors has no efiect on the general nature of the dispersion I produce.

In the same general manner, I am able to produce dispersions of wool, cattle hair, shoddy, or asbestos. As I have previously stated, my invention is not limited to coating the fibres with rubber, or like substances alone, but asphalt, Waxes and parafiin may be used in the manner specified. In the case of wax the addition of an ethanol-amine may be found helpfuland in all cases a 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 proportions stated therein. Those familiar with the art will recognize that the proportion of fibre which can be added may vary through wide limis employed to indicate-a system involving a continuous phase and at least one dispersed phase wherein the continuous phase comprises water, and the discontinuous or dispersed phase comprises solid particles freely suspended in the continuous phase. Such a systemis distinguished from a mere mixture by the fact that the dispersed phase is stable and does not have any substantial tendency to settle out.

I claim:

1. The method of making a stable aqueous dispersion which comprises milling cellulosic fibres into rubber to coat the fibres with rubber and then intensively working the resulting mass with water and a dispersing agent selected from the class consisting of casein, glue, gelatin, karaya, sea moss and algin to disperse the mass as a stable disperse phase in water.

2. That method of producing a water dispersion containing rubber and a substantial proportion of fibre both in the disperse phase which includes the separate steps of coating said fibre by coagulating latex thereon, incorporating said coated fibres in an additional quantity of rubber by milling and then forming a dispersionby working the milled batch in the presence of water and a material selected from the class consisting of casein, glue, gelatin, karaya, sea moss and the algins.

3. The method of making a stable aqueous dispersion which comprises milling cellulosic fibres into a waterrepellent substance selected from the class consisting of rubber, asphalt, paraflin, and waxes to coat the fibres with said substance and then intensively working the resulting mass with water and a material selected from the class consisting of casein, glue, gelatin, karaya, sea moss and algin to disperse the mass as a stable disperse phase in water.

4. A stable aqueous dispersion, being the product of the process of claim 1.

a 5 A stable aqueous dispersion, being the prodnot of the process of claim 2.

6. A stable aqueous dispersion, being the product of the process of claim 3.

. KENNETH TATOR.

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