US1921780A - Wood fiber mass - Google Patents

Description

Patented Aug. 8, 1933- woon maximise Fritz Riihlemann, wousrruni' j t t Herdey,Bautzen,Germany v No Application August 15, 1931, Serial No. 557,426, and 1930 in Germany September 11, v

"The present invention relates to a new product made from wood, being in the form of a loose mass of wood fibers substantially individually free and readily reconverted into pulp by mechanical means or by being immersed in liquids.

One of the objects of theinvention is to produce a loose mass of wood fiber, or mechanical wood pulp, from which the cementing-agents and adhesive substances have been removed to a greater or lesser extent. 1

A further object of the inventionis to produce mechanical wood pulp of such a nature as will readily-lend itself to further disintegration and manufacture into commercial products.

7 Other objects of the invention will become apparent from the furtheihescription hereinbelow and the claims.

' Mood or wood-like plants,. mechanically disin tegrated by means of grindingstones or in any other manner into .fibers and fiber bundles, are termed groundwood or mechanical wood pulp.

Originally the groundwood, after partial removal of a the water, was filled into sacks and sold in a wet condition. Later on, the removal ofthe water was more thoroughly carried out on drying machines or in presses, and the groundwood was sold commercially in the form ofmoist or dry sheets, rolls, lumps or in loose form. Besides the individual fibers and fiber bundles, groundwood is chiefiy composed of fiber, fragments and fiber mucilage. During the extraction of the water, and in greater measure during the drying operation, the fiber fragments and fiber mucilage produce a cementitious substance which joins the fibers firmly together. By plac ing the groundwood upon a sieve or a paper machine wire, either in thin or thick layers, for the extraction of the water, paper or cardboard is produced.

fibers is possible only with special machines requiring considerable power and causing the fibers to lose their original character. Groundwood of this nature is suitable only for the manufacture of paper, board and cardboard, for which the cementing together of the individual fibers with the fiber fragments and fiber mucilage is a necessary-condition. 3 Consequently the uses *ror 'groundwood of this description are limited.

The cementing together of the individual fibers through the fiber fragments. and fiber mucilage also occurs when afibrous felt is being formed from groundwood by means of su'ctioni. e., without presses-and by drying in a vacuum; It is therefore not possible again to disintegrate groundwood from-which thewater has been removed and which has'bee'n-dried in this manner,

into its original loose fibers without them. 2

1 In order to find added uses' for wood after it has been reduced mechanically intoindividual fibers and fiber bundles, it isimportant, accord--' 'ing to the invention, to remove the causes which 7 produce the cementing togetherof the individual fibers.

The invention relates tothe' productionof a mass of wood fibers which consists .exclusively 5 of long individualwood fibers and fiber bundles and completely free from fiber mucilage and poor in fiber-fragments. f v w, I

In order more easily to attain this object, the 7 percentage of fiber fragmentsand fiber muci*-..-

lage, in comparison with the long fibers,- kept correspondingly small even during the orig?- inal mechanical disintegration of the wood." It

is important that the fiber mucilageandthecolloidall'ydissolved fiber fragments removed by washing. This makes. it possible again subsequently to disintegrate thedried material into the formof uninjured Original fibers. While, however, the disintegration of the wood into the commercially known groundwood or mechanical wood pulp, in which a large percentage of short fibers and especially of fiber fra ents and fiber mucilage is desirable,'-'is possible by the expenditure of a great deal of power, the new I above mentioned method of the disintegration of thev wood into long fibers and fiber bundles requires a considerably smaller amount of power.

The new wood fiber mass has a loose, homogeneous fibrous structure which is not cemented together not interfelted and which resembles the structure of raw cotton.-

The new-wood fiber mass, is ordinarily and commercially sold airdi'y in the form of thick sheets or cakes or in other desired form. The separation of the fibers of this wood fiber mass for conversion can be eflected with the least consumption of power. in a dry condition by known means, as for instance by carding and the like. The dry wood fiber mass, reduced to individual fibers. canbe used for example when the be completely.

the dried wood fiber mass can be reduced to its individual, uninjured original fibers simply by soaking the mass in a liquid. The wood fiber mass can also be converted directly from a pulpy condition, that is to say, prior to the removal of the water and the drying of the same. A special advantage of the new wood, fiber mass consists in the fact that the disintegration of the .wood fiber mass, from whichvthe water has been extracted without pressure, is accomplished more easily and with considerably less consumption of power than is the case with the groundwood above mentioned, namely that from which the water has been removed by means of pressure.

The new wood fiber mass can be produced,-

for instance 'in the following manner:

The wood or wood-like plants are mechani-- cally disintegrated with the addition-of water by means of the usual wood grinders or wood chopping machines in combination with rasps, mills, etc., wherein it is of advantage to be careful to preserve the long fibers and fiber bundles. The

- fiber pulp thus obtained is subjected to a washing operation with water which completely removes the fiber-mucilage and the colloidally dissolved fiber fragments from the mass. After the removal of these substances, the mass is ready for conversion into articles by processes in which the presence of water is required or not deleterious. If, on the other hand, the wood fiber mass is required'to be dry for further conversion, the water is removed and thematerial dried, for examplein-rotating perforated drums through which air flows, but without special grated'wood fiber mass from which water-soluble application ,of pressure. Other known equipment may also be used for the removal of the water andfor the drying,l.such as cylinderand flat wire wet machines, vacuum installations or drains, drying cylinders and the like. The main object is to avoid them of undue pressure which would result in undesired felting of the fibers.

The described properties of the new wood fiber mass oifer chiefiy the possibility to usethe same for the manufacture of certain synthetic mate-. rial, for litter, for a material for absorbing liquids, and for the production of heat-', coldand sound-' insulating substances. Moreover it has now only become possible through the use of this new dry wood fiber mass toproduce mixtures thereof with pulverized binding materialswhich on addition of water, and after swelling, take on solid forms.

The wood fiber mass described is an entirely new product which'can be used'either by itself or as primary material for conversion into other products.

Weclaim: 1 v" 1. The process of producing a loose mass of groundwood fibers which comprises grinding wood in presence of water to produce individual fibers and fiber bundles, washing fiber-mucilage and colloidally dispersed fibers from the resulting mass, and drying the. latter without application of substantial pressure.

2. The process ofproducin'g wood fiber free from slimy particles and water-soluble matter which comprises grinding wood in the presence of water to produce individual fibers and fiber-bundles, and washing said fibers and fiber-bundles substantially free from said particles and soluble matter.

3. The process of producing wood fiber free from slimy particles and water-soluble matter which comprises comminuting wood-to produce loosened woody fibers and fiber-bundles and washing the same with water to remove therefrom slimy particles and water-soluble gums. 1113- 4. As a new product, a mechanically disinte r grated wood fiber mass from which water-soluble matter and slimy particles have been removed by washing merely with water.

' 5. As a new product, a mechanically disinte--' matter and slimy particles have been removed by washing merely .with water and which has been dried'without application of pressure.

FRITZ RI'JI-ILEMANN.

OTTO RUDOLF' HERDEY.