US1647528A - Monolithic structure and method of making same - Google Patents

Description

Patented -Nov.' :1, 19 27.

'UNITEDTJSTATES wr'rmnmr norrm Korma, or new roux, N. Y., ASSIGNOR' ro rnxas PATENT OFFICE.

qunr SULPHUR comm, or BAY crrr, waxes, a oonrona'rron or Texas.

Honour rare srnucruna Ann mnrnon or mxmo same.

No Drawing.

This invention relates to monolithic structures and has for its object the provisionQ-of a method of producing such structures Wlth a'base of molded wood pulp. The invention also involves a new and improved wood pulp article having the characteristics of .a highly mineralized substance which is very strong and not at all brittle. 1

sulfur which'has solidified or congealed in The present invention contemplates a.

method of producing molded wood pulp articles having a substantially monolithic structure torender molded wood pulp articles better suited. for their common uses,

and moreover, to adapt'them for uses for which they have been heretofore unsuitable. I have discovered that molded wood pulp articles, treated in accordance with the invention, are water proof and extremely resistant to acids and corrosive liquors. Moreover, such articles, thus treated, possem greatlysuperior strength and increased dielectric strength,'without material decrease in resiliency.

The articles treated in accordance with the invention I prefer to call molded wood pulp articles. By molded wood pulpvarticle's, I

refer to articles formed in an ,appropriate manner within a fine mesh wire screen or the like from disintegrated wood'pulp produced during the intermediate steps in the manufacture-of paper. Such a wood pulp may be Inolded,, cast or blown within a -fine mesh wire screen in accordance with the 1 to'congeal therein to obtain a relatively hard impervious mass of monolithic structure,

Although sulfur is a brittle, relatively weak material, nevertheless, when'the pores or interstices of the molded wood pulp article are impregnated with congealed sulfur, the strength of the resulting article is from five to eight times greater than that of the origim1, ,article. By congealed sulfur, I mean situ in the interstices of a molded wood pulp article, the sulfur beinginitially introduced in themolten or liquid condition'into the interstices.

I have discovered that molded wood pulp Application filed October 27, 1924. Serial No. 746,251.

with molten sulfur, since they are extremely porous and may be'made with walls of any reasonable thickness. In such articles, the

absorption of molten sulfur amounts to many times the weight of the untreated article, but is usually'from three to four times the \original weight. After impregnation with sulfur, the. finished product has a monolithicstructure and may consist in some cases of as much as eighty-five per cent by weight of sulfur. This indicates that the molded wood pulp article simply serves as a carrier or vehicle for the sulfur and. that the impregnated article is a radically difierent and new material. In other words, this processed woodpulp ceases to be a woody structure and takes on the characteristics of a highly mineralized substance which is, how-. over, very strong, not at all brittle, and can not be likened to an article of-similar form or configuration cast from sulfur alone. The molded wood'pulp article impregnated with sulfur in accordance 'th the invention is from five to eight tims tronger than the untreated material and is waterv proof, impervious and extremely resistant to the action of practically all destructiveagencies, especially the various corrosive acids and other chemicals.

Various methods may be employed for impregnating molded wood pulp articles with sulfur in accordance with the invention. order to secure the most satisfactory impregnation of the article with sulfur, the

.pores or interstices of the article must be freed of gases'to permit filling of the poreswithsulfur. When'it is desired to impregnate relatively small molded .wood pulp objects, they may be introduced, either with or without preheating, into a bath of molten sulfur at a temperature of about 120 C. at which temperature the sulfur is a relatively thin li uid. The molded wood pulp articles should e completely submerged in the bath, and, if necessary, means should be provided for holding them below the surface of the sulfur. I have found that it is sometimes desirable and advantageous to give the article to be impregnated a sli ht rotary movement in the molten sulfur atlil' The productspf various-forms and configurasulfur may be. increased toiabout 220 C. at

tions are ideally adapted for impregnation which temperature the sulfur approaches the 7,

viscous stage. This causes the heat of the bath to penetrate well into the article and completely expel the air or other gases from its pores. After the gases have been thor- 6 oughly expelled, as indicated, by'thc reduction in the amount of gas bubbles coming to the surface of the bath, the temperature of the bath may be lowered until the sulfur again reaches the thin liquid stage. The

10 gases now having been removed from the pores of the molded wood pulp articles, the

thin liquid sulfur will gradually enter and 11 the pores of the material.- The impregnation ofthe articles with sulfur will generally 15 becomplete in from-twelve to twenty-four hours", depending upon the size and shape of the object being impregnated. During this soaking period, it may be found advantageous to'occasionally raise the temperature of the bath temporarily as this seems to aid in the impregnation.

When particularly complete impregnation is desired, great care should be paid to 'the manner of withdrawing the article from the 5 bath. For example, both the bath and the article should be allowed to cool until when a surface of the article is lifted from contact with the bath, the sulfur thereon begins to show indications of congealing. Thenthe article is slowly withdrawn from the bath and the sulfur on the surface of the article begins to congeal during the operation. It is sometimes advantageous and desirable when withdrawing the article from the sulfur bath, to subject the article to the action distortion. Molded wood pulp articles, so

treated, are from five to eight times stronger than the original without substantial change in resiliency.

The new improved product of the invention is not only wet-resistant but water proof and action of 15% acetic acid, 20% macid mixturespf fe'rro us and ferric chloride,

is extremely resistant to acids and corrosive liquids. 'I have foundthat containersmade from molded wood pulp subsequently impregnated with sulfur will withstand the phosphoric 20% hydrochloric acid, 19% nitric acid, 14% sulfuric acid andeven of hydrofluoric acid. I have found that molded wood pulp articles 5 of appropriate configuration and treated in resistance to chemlcals.

of utility for fibrous articles where unimpregnated article,

mamas accordance-with the invention are adapted for use as battery jars, forming tanks,.electrolytic. cells, textile cones and for many other purposes requiring great strength and Such articles fulfill to a remarkable degree the requirements of their particular uses.

I have also discovered that this new material, consisting of molded wood pulp as a base with crystalline sulfur permeating throughout its mass and occupying substantially every fiber and 'void,-may be given an excellent finish by sanding and polishing. This finish has the appearance of old ivory. If desired, many attractive colors ma be imparted to the molded wood pulp artic e by incorporating such colors, either in the form of a pigment or certain organic dyes, in the sulfur bath and thereby carrying them into the-molded wood pulp article durmg impregnation. iodine; I am aware that it has been suggested heretofore to impregnate paper with sulfur. I have found, however, that when paper is impregnated with sulfur in accordance with "these 'prior. suggestions, it becomes extremely brittle and cannot bebent. For all practical purposes, the paper'is actually weakened by the process, and on account of its extreme brittleness, it cannot be used forthe making of containers or other products which require a high degree,of pliability in the manufacturing process. I have discovered, however, that molded wood pulp;- articles of the type heretofore described, when 1m regnated with congealed sulfur in 'accor ance,

with the invention, become in effect a monol1th1c structurefeomprlsmg a mass'of sulfur reinforced throughout by wood pulpfibers which give it great strength and serve as a base to produce different forms and shapes which cannotbe madein anyother way, and

posses other advantageous propert1es as heretofore set forth.

'I claim: 1. The method of producing an article having a substantially monolithic structure which comprises immersing a porous article in a bath'of molten sulfur, maintaining the article in the bath until the interstices of the article are impregnated to the desired extent with the sulfur, then lowering the temperature of the molten sulfur until'it shows indications of congealing, and subsequently withdrawing the sulfur-impregnated article from the bathof molten sulfur in a manner that the sulfur-in the interstices'thereof congeals in situ.

2. The method of producing an article having a substantially'monolithic structure which comprises immersing a molded wood pjulp article in a bath of molten sulfur at a temperature below that which would partially carbonize the wood, maintaining the This is notablythe case with article in the bath until the interstices of the article are impregnated to the deslred extent with sulfur, then lowering the tempera-- that the sulfur in the interstices thereof congeals in situ. p

3. The method of producing an article having a substantially monolithic structure which comprises immersing a porous article in a bath of molten sulfur, raising the temperature of the molten sulfur to assist in removing gases from the pores of the article, thereafter reducing the temperature of the sulfur to a point only slightly above the melting temperature of the sulfur, maintaining the article in the sulfur at the reduced temperature until the interstices thereof become impregnated to the desired extent, then further reducing-the temperature of the sulfur until it shows indications of congealingyand subsequently withdrawing the sulfur-impregnated article from the bath of molten sulfur in a manner that the sulfur in the interstices thereof congeals in situ. I

4. The method of producing an article having a substantially monolithic structure which comprises immersing a molded wood pulp article in a bath of molten sulfur, maintaining the article in the bath until the interstices of the article are impregnatel to the desired extent with the sulfur, then lowering the temperature of the molten sulfur until it shows indications of congealing, and

subsequently withdrawing the sulfur-impreg-.-

nate'cl article from the bath of molten sulfur in a manner that the sulfur in the'interstices thereof congeals in situ.

tially carbonize'the wood, maintaining the' article in the bath until the interstices there: of are impregnated to the desired extent with sulfur, then lowering the temperature of the molten sulfur until it shows indications of. congealing and subsequently withdrawing the sulfur impregnated article from the bath of molten sulfur and expediting the congealment of the sulfur to prevent the escape of a portion of the sulfur from the pores of the article. 6. The method of producing an article having a substantially monolithic structure which comprises immersing a porous article in a bath of molten sulfur, raising the temperature of the sulfurto assist in removlng.

gases from the pores of the article, thereafter, reducing the temperature of the sulfur to a point onl slightly above the melting, temperature of the sulfur, maintaining the article in the sulfur at the reducedtemperature until the interstices thereof become impregnated to the desired extent, then further reducing the temperaturerof the sulfur until it shows indications of congealing and subsequently withdrawing the sulfur-impregnated article from the bath of molten sulfur and exped'ting the congealment of the sulfur to preven the escape ofa portion of the sulfur from-thepores of the article.

7. The method of producing an article having a substantially monolithic structure which comprises immersing a. porous article in a bath of molten-sulfur, maintaining the article in the bath until the interstices thereof are impregnated to the desired extent with sulfur, then lowering the temperature of the molten sulfur until it shows indications of congealing and subsequently withdrawing the sulfur-impregnated article from the bath of molten sulfur and subjectin it to the action of a cold air blast to expedite the congealment of the sulfur and prevent the escape of a portion of the sulfur from the pores of the article.

In testimony whereof I aflix my signature.