US1574254A - Process of tbeating bagasse for fiber-making purposes - Google Patents

Description

description of the invention, such Patented Feb. 23, 1926.

UNITED STATES TREADWAY B. MUNROE, 0F FOR-EST GLEN, MARYLAND.-

PROCESS-0F TREATING BAGASSE FOR FIBER-MAKINGIPURPOSES.

No Drawing. Application filed J'u1y7,

To all whom it may concern:

Be it known that l, TREADWAY ll. MUN- ROE, a citizen of the United States, residing at Forest Glen, in the county of Montgomery and State of Maryland, have invented certain new and useful Improvements in Processes of Treating Bagasse for Fiber- Making' Purposes; and I do hereby declare the following to be a full, clear, and exact as will enable others skilled in the art-to which it appertains to make and use the same.

This invention relates to a process of treating bagasse for fiber making purposes and especially adapted for the purpose of making fiber boards. It has for its object to provide a procedure which will be more efficient in action and less costly to carry out than those heretofore proposed.

With these and other objects in view, the invention consists in the novel steps and combinations of steps constituting the process, all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

In order that the precise invention may be the more clearly understood, it is said As is Well known, when bagasse fibers are subjected to a cooking action in the presence of chemicals to make fiber boards, they are often found to be extremely harsh, hard to cook, hard to refine in the Clallin machines and they do not constitute a product as soft and pliable as-is desired.

According to this invention on the other hand, it is found that if the fibers are subjected to a fermenting action before they are cooked, they will be so loosened from the cementing material which holds the individual fibers together that said fibers will be so soft and pliable that very small quantities of chemicals will be needed to cook the same, and in many cases no chemicals at all -Will be required in the cooking process.

It is further well known that when the chemically cooked fibers of bagasse are madeup into a fiber board, there is considerable difficulty often experienced in uniformly drying and draining the same. That is to say, the drying and draining of-these fibers is found to be so uneven that the board is liable to curl up and to not be in such a smooth flat condition, as is desired for a commercially successful board. But, again,

according to this invention, it is found that if the fibers are fermented as above men- 1924. Serial N0. 724,712.

' tioned so as to render them soft and yielding and if they are ,then cooked in water with either a very small quantity of chemicals or with none at all, and if they are mixed with a suitable preccntagc of wood ul) orw round 11) news )a )er material either bcforc'or after cooking but preferably should be comparatively inexpensive and very certain in results or else the cost of a.

satisfactory product will be prohibitive.

I overcome the cost problem by proceeding as follows It is well known that bagasse as it comes from the sugar mills in addition to containing say 50% of moisture, also contains from 3% to 4% of sugar and other substances which cause the bagasse to undergo fermentations and decay ifthese actions are not properly controlled. \Vhile it is true if the bagasse is dried at the mill it will escape these fermentations, yet it is further well known that such drying is commercially too'expensive to be practicable.

Therefore, in proceeding according to this invention, the bagasse is baled at the mill, it is shipped to the place of use, and

these bales are placed in piles on well dried ground,in such manner that a minimum of surface will be exposed to the weather and sufficient ventilation between the bales will be provided to permit moisture, vapors and gases to freely escape. It is found to be sufficient, ifthe bales are piled fiat on the ground in a rectangular layer, with a few inches of space separating the sides and ends of the bales. Then, on top of this layer another similar layer is piled, each bale of the "second layer breaking joint with the bales underneath and likewise separated by a few inches from each other. The upper or second layer is made of a less area than the bottom layer, so that 'a stepped or pyramid formation is started by disposing of the outer bales of the second layer, well inside the outer bales of the lower layer. This form of piling is continued, each upper layer being of a less area than the next lower layer, each bale breaking joint with the vents or passages between the lower bales, and each bale in a layer being separated on its sides and ends from an adjacent bale.

that the fibers are soft and silky to the touch and their strengthis unimpaired. If

this fermentation is allowed to proceed, unprotected from the weather the fiber itself will be injured so it is found tobe desirable to' open'up a few of the fermented bales, and spread a layer of bagasse 6 or 8 inches thick over the entire pile of bales. After this is done, the pile of bales may be allowed to age for a period of from a month to a year, during which time the fe nented bagasse may be freely used for fiber m king purposes.

Bales from these piles are broken open and loosened out the fibers separated and fed to a cooker in which they may be subjected to the action of hot water alone for a period of from 45 minutes to two and one-half hours. While it is well known that bagasse fibers may be cooked with alkalies and other suitable chemicals, such cooking has a disfrom 10% to 50%.

advantage that it dissolves valuable constituents and that due to the action of hydration of the fiber and the production of oxycellulose and other products, the fiber is hard to handle in all pulp forming equipments. By softening the fermented fiber with hydrolysis in hot water on the other hand, the cementitious material is removed from between the fibers rendering them in a suitable condition for refining by well known machines such as Claflins, etc., without the disadvantages experienced when such fibers are cooked with caustic or other chemicals. 4

It is found, however, that cooking fibers with chemicals and hot water, or even without chemicals, as described above does not produce fibers with all the properties desired in the manufacture of aheat insulating board,

for the fibers are rather long and coarse and produce a board that does not have a good surface and one which it is difiicult to waterproof. These objections, however, are overcome in this invention by adding to such bagasse fibers, other fibers in a proportion Such fibers are preferably ground wood, waste newspapers, or fibers that are classed by paper makers as close stock, also what s known as wood pulp tailings are satisfactoryfor'this purpose. These fibers are preferably employed by adding them to the fermented bagasse as it goes into the cooker, for in addition to their becoming well mixed with the bagasse fibers, these said other fibers are .the products of hydrolysis by the water present being drained from the fiber and replaced with fresh water two or three times, or until the mixture of fibers are practically free from the substances dissolved from the hot water. The mixed fibers are then ready for refining, and maybe pumped to a Claflin or other suitable refining equipment, and refined into a mixture of fibers suitable for the purpose desired. At this point may be added any suitable Waterproofing material and a fireproofing material may be applied at any suitable time later.

In the manufacture of heat insulating boards, this mixture of bagasse and other. fibers with water in the proportion of onetenth to one per cent of fibers with ninetynine and nine-tenths to ninety-nine per-cent water, is fed into a continuous board forming machine, such as that disclosed in U. S. Patent #1,456,608, where it is formed into a wet board containing 25% to 40% fiber and 7 5% to water. It is now necessary to remove this moisture from the board and this is accomplished by subjecting the wet board to the action of from 250 1*. to 350 F. of heat in any suitable continuous steam.

heated drier, for a period of from one to three hours to reduce the moisture content from 60% or down to less than 5%. It is found that the wood pulp or other close fibers added to the board are particularly valuable'at this point of the procedure for bagasse fibers are what is known as free stock, that is, they do not hold on to their water tenaciously but give it up rather fre' while wood or similar fibers being what is known as close stock do not give up their moisture freely. The result is it is found that in the drier, these wood or similar fibers which are mixed with the bagasse the temperature of'250 F. to 350 F. from.

scorching the surface of the board as it becomes progressively drier. This humidity will also prevent the board becoming dry so moisture canquick on the surface that the not come from the interior to said surface. When this fiber board isdry, it is a'good heat insulator and is quite water resisting,

' so therefore if a layer on the surface becomes dry before the moisture has been removed ely under the influence of heat,.

from the interior of the board, it will be seen that this surface layer will act as a heat insulator preventing the penetrating of the heat to the interior, and will therefore reduce the moisture coming from the interior. It is also found that this addition of close fibers to the bagasse fibers, assists materially in the production of aboard that issues from the drier absolutely fiat and smooth and with no tendency to warp or curl.

This most desirable result is assisted by cooking fermented fibers with hot water rather than with chemicals, because when ordinary bagasse fibers are cooked with chemicals and subjected to heat it is found they undergo considerable shrinkage in length. Such fibers made into boards, and subjected to heat, of course, set up uncontrollable strains in drying that cause the boards to curl. The close fibers by controlling the extraction of the moisture from the bagasse fibers also control this shrinkage of the bagasse fibers because they control the time that these long fibers must be subjected to the heat in order to manufacture the board. It is also found that these close wood fibers fill in between the bagasse fibers, thus creating minute air spaces instead of larger air spaces, and they fill up particularlv the interstices on the surface of the finished fiber board thus rendering it more ornamental.

hat is claimed is 1. The process of preparing bagasse for pulp making purposes which consists in disposing said'bagasse in piles having ventilating channels for the escape of gases and vapors; subjecting said piled bagasse to a fatty acid fermentation to loosen the fibers present from their incrusting materials; covering said piled bagasse to partially protect it from the weather before the strength of the fibers is impaired; mixing said fibers with other fibers which give up their moisture less freely than do bagasse-fibers; cooking said fermented fibers; and refiningthe cooked fibers. 1

2. The process of preparing begasse for pulp making purposes which consists in subjecting said bagasse to an acetic acid fermentation; stopping said fermentation before the strength of the fibersis impaired; mixing the fermented bagasse with fibers derived from wood; subjecting the mixture to a cooking'action; and refining the cooked mixture of fibers.

3. The process of making a heat insulating board from bagasse which includes in subjecting said bagasse to a fermentin ac tion; stopping said action after the fibers present have been loosened from the ocmentitious material binding the same and before the strength of said fibers has been impaired; mixing said fermented bagasse with wood fibers; subjecting the mixture of fibers thus produced to a boiling action; subjecting the mixture to a refining action; forming the refined mixture into a board; and drying said board.

4. The process of preparing bagasse for pulp making purposes which consists in baling said bagasse; disposing said baled bagasse in piles having ventilating channels for the escape of gases and vapors; subjecting said piled bagasse to a fatty acid fermentation to loosen the fibers present from their incrusting materials; covering said piled and baled bagasse to partially protect it from the weather before the strength of the fibers is impaired; cooking said fermented fibers with hot water containing no added chemicals; mixing said fibers with other fibers which give up their moisture less freely than do bagasse fibers; and refining the cooked fibers. I

5. The process of preparing bagasse for pulp making purposes which consists in subjecting said bagasse to an acetic acid fermentation; stopping said fermentation before the strength of the fibers is impaired; mixing the fermented bagasse with more than 3% of fibers derived from wood; subjecting the mixture to a cooking action in water to which no chemicals have been added; and refining the cooked mixture of fibers.

6. The process of making a heat insulating board from bagasse which includes subjecting said bagasse to a fermenting action; stopping said action after the fibers present have been loosened from the cementitious material binding the same and before the strength of said fibers has been impaired; mixing said fermented bagasse with more than 3% of wood fibers; subjecting the mixture of fibers to a boiling action; subjecting the mixture to a refining action; forming the refined mixture into a board; and drying said board in an atmosphere containing suflicient moisture to prevent scorching the board..

7 The process of making a heat insulating fiber board which consists in subjecting piled bagasse to an acetic acid fermentation until the fibers present are partially loosened from the bundles in which they naturally occur; stopping said fermentation before the strength of the fibers is impaired; mixing with the fermented bagasse a sufficient quan tity of fibers derived from wood to aid in drying the formed board; subjecting the mixture thus obtained to a cooking action; refining the cooked mixture of fibers; separating from the refined mixture thus obtained any objectionable constituents derived from the cooking action; adding a fire re-- sis'ting material to said mixture; and forming the mass thus obtained into a board.

8. The process of making a heat insulat- "ing fiber board which consists in subjecting piled bagasse to an acetic acid fermentation until the fibers present are partially loosened from the bundles in which they naturally occur; stopping said fermentation before the strength of the fibers is impaired; mixing with the fermented bagasse a sufiicient quantity of ground fibers derived from Wood to aid in drying the formed board; subjecting the mixture thus obtained to a cooking action in water devoid of chemicals; refining the cooked mixture of fibers; separating from the refined mixture thus obtained any objectionable constituents derived from the cooking action; forming the mass thus obtained into a board; and drying said board in a moist atmosphere.

9. The process of making a heat insulating fiber board, which consists in mixing fermented bagasse, fibers with wood fibers; cooking the mixture in water; refining the cooked mixture; forming a board from the refined mixture; and drying said board.

10. The process of making a heat insulating fiber board which consists in mixing fermented bagasse fibers with wood fibers; cooking the mixture in water; refining the cooked mixture; adding a waterproofing material to the refined fibers thus produced; forming a board from the refined and waterproofed mixture; and drying said board.

11. The process of making a heat insulating fiber board, which consists in mixing fermented bagasse fibers with wood fibers; cooking the mixture in water; refining the cooked mixture; adding a waterproofing material to the refined fibers thus produced; forming a board from the refined mixture; drying said board; and fireproofing said board.

In testimony whereof I affix my signature.

' TREADWAY B. MUNRQE.