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Патент USA US2131097

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Y Patented Sept.vv 27,v i938
oilio,‘ assignor to The
Pierre DrewsemSandusky,
Barrett Company, New York, N. Y., a corpora
tion of New Jersey.
NofDrawing. ~ Original application February 4, h
now Patent No..
1926, Serial \ No.‘ 86,098,
2,029,310. Divided‘ and this application No
vemb'er 16, 1935, Serial No. 50,151 I
'(ci. sea-m1
following ' detailed. descripi
This invention relates to felt and more'par? will appear from the
ticularly to felt adapted to be saturated with wa
‘ In accordance with this invention‘, wood-?bers
terproo?ng compounds such as asphalt, coal tar, of relatively great strength are blended with ‘other , ' 1
coal tar pitch or other bituminous waterproo?ng wood ?bers of relatively open structure and have‘ ‘ 5 '
material, to form waterproof products for build , ing high absorptive capacity in suitable propor
ing, flooring, roo?ng and like purposes.
tions to‘ produce a felt having the desired strength, 1 .
\ Heretofore the manufacture of felt intended to
\bsorptivelcapacity. ‘I
be saturated with Waterproo?ng compounds, such and
.As ?bers in which strength is the predominant
as liquid bituminous materials has usually been ‘mamteristm- I may employ unbleached's'ul?te 10
10 accomplished by employing one or more of the pulpor kraft pu1p_
, I
‘ 1 The preparation-of sul?te pulpis a process well
(1) Rags which contain substantially a mix-i known in the art. 'It is preferred that the ?bers
" of‘wood to the"
ture of cotton and wool; _,
resulting from the subjection
(2) Rags consisting substantially of cotton;_
sul?te process be employed in an. unbleached
(3) Rags which contain jute ?ber in-the form
condition since such ?bers ‘ possess . { relatively
of waste bagging;
‘ ‘
greater strength than bleached ?bers. Drastic‘
(4) Rags which contain old carpets composed or.
over bleaching. particularly ‘ with strong
largely of jute with quantities of cotton and wool; bleaching agentsv ‘such; as chlorine,; shouldbe
(5) Rags which contain. rag clippings of all
avoided in case a felt of high strength is desired‘
grades with varying amounts of paper; and
the reason that such bleaching weakens‘ the
(6) Paper stock composed largely of waste ?bers
and hence would result in an‘ inferior felt
as compared with a felt containing unbleached
These materials are partially‘disintegrated in ?bers or ?bers which have been subjected to only
following as raw materials:
per-making machines.
Rags are a relatively expensive raw material
a mild bleaching operation.
As strength ?bers, the sul?te pulp may be part
ly or wholly replaced by. wood ?bers known‘ gen
erally in the paper making artjas kraft (includ
. ing waste kraft pulp). '
and the use of substantial proportions of the
same in the manufacture of felt results in a
relatively expensive product.
Paper stock composed largely of waste paper
is a less expensive raw material than rags, but
the use of large quantities of this material in
the manufacture of felt tends to harden or stiffen
the felt sheets and produce a product of inferior
quality for many purposes.
Wood ?bers have been recognized as a low cost
material and proposals have been made tosub
stitute such ?bers for a portion of the more v
expensive ?bers hereinabove mentioned.
rag cutters and thereafter,.while in suspension in
water, are beaten in paper mill beaters, then
jordaned if desired and ?nally formed into a
‘continuous sheet on Fourdrinier ‘or cylinder pa
One object of this invention is to produce a low
cost felt, of relatively great strength and having
a relatively high capacity for absorbing water
proo?ng compounds, consisting substantially en
tirely of wood fibers. A further object of the
invention is the production of felt by blending
wood ?bers whose principal function is to impart
50 strength to the felt with other wood ?bers of a
Since the preparation of beta sul?te stipend 30
kraft pulp is well known in ‘the paper: making
art, and thes e materials are commercially avail
able, further descriptlon of the processes for the
preparation thereof is believed to be unnecessary.
Of the two classes of wood ?bers, those to be 35
employed principally for imparting high absorp
tive capacity to the felt may be, prepared by
cooking wood substances in an alkaline medium.
and disintegrating the ?bers by mechanical treat-‘
by _ treatment with‘edge run- 40
ners or in beating engines or Jordan, engines.
ment, for example,
As an example of the preparation of absorp
tive ?bers, wood substances such as spruce or
hemlock may be treated at elevated tempera
tures in the presence of a solution of caustic soda 45
having a str ength of ten per cent or higher by .
weight. It is preferred to perform the cooking
operation at temperatures of over 90° C. and I
have found that ?bers having a high absorptive
capacity may be prepared by cooking spruce'chips
or shavings in the presence of a solution of
character to impart a high capacity for absorp- - caustic sodacontaining 5 to 10 percent caustic
soda based von the weight of the ?bers ‘at a tem
tion to form a felt havingvthe desired strength
perature‘of from 90 to 100° C. andsubsequently I
?bers and disintegrating them in a
Other objects and advantages'of my invention ‘washing the
and absorptive capacity.
- beatingengine. In lieu of caustic soda solution,
a solution of other alkali may be employed as the
cooking medium; It will be understood to those
skilled in the art that the time for which the
wood ?bers‘are subjected to cooking or beating
one felt’ suitable for ‘manufacturing mineral sur
faced roo?ng mayvconsist of about 25 percent
of strength ?bers and about 75 per cent of ab
sorptive ?bers. Such a felt having a thickness
of 0.057 inch will have a tensile strength of 27
as hereinabove described, will depend on many lbs. per inch of sheet width and will absorb about
factors among which may be mentioned the tem
180 per cent of its weight of asphalt.
perature of the solution to which the ?bers are ‘
It will be seenthat the felt of the present in
subjected, the strength of the solution, the
10 amount of the charge, etc., and that the treat
ment of the ?bers is carried out until the ?bers
are disintegrated and rendered absorbent to the
desired extent which may be determined by in
specting and testing the ?bers in the cooking or
16 beating engine as the case may be.
Absorptive ?bers may also be formed by cook
ing wood substances, such as spruce or hemlock
chips or shavings in a calcium pentasul?de so
lution as described in U..S. Patent No. 996,225
of June 27, 1911 to Viggoj Drewsen, after which
the ?bers are disintegrated by treatment with
edge runners or in the ordinary form of beating
engine or Jordan engine. Instead of a solution
of calcium pentasul?de, polysul?des of certain
other alkali or alkaline earth materials, such as
sodium pentasul?de, may be employed as the
cooking ‘medium.
.Having produced the pulp containing ?bers of
relatively high ‘strength and pulp containing
vention consists substantially entirely of wood
?bers and possesses advantageous properties of
high strength and a high capacity for,absorp
tion of waterproo?ng compounds. The felt is
made from low cost materials and therefore can
be produced more cheaply than the usual felt‘
products containing substantial percentages of 15
relatively expensive ?bers such as rag ?bers. My
felt isadmirably adapted for employment as a
?brous base for water-proofed materials to be
employed for building purposes such, for ex
ample, as siding and roo?ng.
. 20
This application is a division of my copending
application Serial No. 86,098, ?led February 4, '
1926 which has issued as Patent No. 2,029,310,
February 4, 1936.
_ '
vIt is to be understood that the above descrip
tion- is to be interpreted as illustrative and' not
in a limiting sense and that this invention is not‘ ~
restricted to the present disclosure otherwise than as de?ned by the appended claims.
_ "
I claim:
?bers to be employed for imparting high absorp
tive capacity to the felt, the two types of ?bers
1. A ?exible felt‘sheet consisting substantially
are blended in proportions of from 15 per cent entirely of wood ?bers, said felt containing from
to 45 per cent of strength ?bers with from 55 per
cent to 85 per cent of absorptive ?bers and the
' resulting blend of ?bers is formed into a felt sheet
on Fourdrinier or cylinder felt-making machines.
The percentages of the ‘two types of ?bers may
be varied within the limits stated depending-upon
the type of I felt desired tobe produced. For ex
ample, for a felt of exceptionally great strength
and in which it ,is not important that a large
amount of saturant be absorbed, the proportion
of strength ?bers may be ‘increased'with a cor
responding decrease in the proportion of absorp
45 tive ?bers. On the other hand; if it is desired
to produce a felt having relatively high saturat
15 per cent to 45 per cent of ?bers of relatively
great strength from the group consisting of sul
?te pulp and kraft pulp and from 55 per cent,
to 85 per cent of ?bers having high absorptive
capacity produced by cooking wood‘ with a re
agent of the group consisting of caustic alkali and
alkaline sul?des, said felt being impregnated with .
waterproo?ng ‘material. ' '
2. A ?exible felt sheet consisting substantially
entirely of wood fibers, said felt containing from
15_per cent to 45 per cent of ?bers of relatively
great strength from. the group consisting of sul
?te pulp and knit pulp and from 55 per cent 45
to 85 per centv of ?bers having high absorptive
capacity produced by cooking wood with a re-'
' mg capacity, for example a felt capable of ab
sorbing 150-170 per cent or more, e. g., more agent from the group consisting of caustic soda '
than 200 per cent by weight of bitumen, such as . and polysul?des of alkali and alkali earth metals, ‘
asphalt, the proportion of “absorptive ?bers may
said felt being impregnated with bituminous wa
be increased with a corresponding decrease in
terproo?ng material.
the proportion of strength‘ ?bers. For example,
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