Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles – Utilizing diverse solid particles
Reexamination Certificate
2001-04-11
2003-11-04
Lechert, Jr., Stephen J. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
Utilizing diverse solid particles
C264S126000, C264S113000
Reexamination Certificate
active
06641763
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a fibrous aggregate formed by processing fibrous material comprising fibers in particular, a fibrous aggregate which is relatively low in density and is relatively thick. It also relates to a thermal method for forming such a fibrous aggregate, and an apparatus for forming such a fibrous aggregate.
Conventional methods for forming a fibrous aggregate, which are widely in use, may generally be classified into two groups: the needle punching group and the thermal group. In certain cases, a needle punching method and a thermal method are independently used, whereas in other cases, they are used in combination.
Next, the two groups of fibrous aggregate forming methods will be briefly described.
(1) Needle Punching Method
This is a method for continuously forming a sheet of fibrous aggregate by entangling fibers among themselves; multilayered fibrous material is reciprocally punched through with the use of a needle punching machine which uses a needle called a felting needle.
(2) Thermal Method
This is a method for forming a fibrous aggregate by thermally welding fibers among themselves; a predetermined amount of heat is applied to multilayered fibrous material comprising plural types of fibers different in melting point, so that the fibers with the lower melting point (bonding material) melt and weld the fibers with the higher melting point (structural material), at the intersections of the fibers with the higher melting point. In other words, according to a thermal method, the fibers with the higher melting point serve as structural material, whereas fibers with the lower melting point serve as bonding agent. As for typical thermal methods, there are a method called a heated air conveyer heating chamber method, in which multilayered fibrous material is continuously fed into a heated air conveyer heating chamber to form a continuous form of fibrous aggregate, a method called a molding method, or a batch method, in which multilayered fibrous material is packed into a mold of a predetermined size and is heated to form a block form of fibrous aggregate, which has a predetermined size (size and shape).
Next, the two methods will be described in more detail.
(2-a) Heated Air Conveyer heating chamber Method
FIG. 12
is a schematic sectional view of a conventional heated air conveyer heating chamber used for a thermal fibrous aggregate forming method. As is evident from
FIG. 12
, this heated air conveyer heating chamber
500
has a pair of mesh belts
510
and
520
, which are placed in a manner to vertically oppose each other, with the provision of a predetermined gap between the two belts, in order to move the multilayered fibrous material
600
, in the leftward direction of the drawing, while compressing the multilayered fibrous material
600
from the top and bottom sides (in the direction in which the fibers are stacked), as the multilayered fibrous material
600
is fed from the upper right direction of the drawing. The multilayered fibrous material
600
is actually layers of webs of sheathed fiber. Each web has been produced with the use of a carding machine (unillustrated), a cross-laying machine (unillustrated), or the like, and the fibers in each web have been laid more or less in parallel. The weight per unit of area of the multilayered fibrous material
600
is selected in accordance with its usage. Further, the multilayered fibrous material
600
comprises plural types of fibers different in melting points.
The distance between the two mesh belts
510
and
520
is approximately equal to the thickness of the final product, or a continuous fibrous aggregate
650
, and can be adjusted as necessary. The thickness H of the continuous multilayered fibrous material
600
fed into the heated air conveyer heating chamber
500
is greater that the gap h between the two mesh belts
510
and
520
. After being fed into the heated air conveyer heating chamber
500
, the continuous multilayered fibrous material
600
is compressed all at once to the thickness h by the mesh belt
510
and
520
, and is thermally formed into the continuous fibrous aggregate
650
while remaining in the compressed state.
In order to thermally form the continuous multilayered fibrous material
600
into a continuous fibrous aggregate
650
, an air sending chamber
530
for blowing air, and an air receiving chamber
540
for suctioning the heated air blown out of the air sending chamber
530
, are provided in the heated air conveyer heating chamber
500
. The air sending chamber
530
is provided with an air supplying hole
531
and a plurality of perforations, and is located above the path of the multilayered fibrous material
600
, within the heated air conveyer heating chamber
500
. Heated air is blown into the air sending chamber
530
through the air supplying hole
531
, and is blown out of the air sending chamber
530
through the plurality of perforations
532
to be blown at the multilayered fibrous material
600
. The air receiving chamber
540
is located below the path of the multilayered fibrous material
600
, and is provided with a plurality of perforations
542
and a plurality of air suctioning holes
541
. As the heated air having been blown at the multilayered fibrous material
600
from the air sending chamber
530
, as described above, passes through the multilayered fibrous material
600
, the heated air is suctioned into the air receiving chamber
540
through the plurality of perforations
542
, and is exhausted through the plurality of air suctioning holes
541
.
Upon being introduced into the heated air conveyer heating chamber
500
, the continuous multilayered fibrous material
600
is heated by the heated air blown out of the air sending chamber
530
until its temperature rises to a predetermined one. As described above, the continuous multilayered fibrous material
600
is continuous layers of plural types of fibers different in melting point. Therefore, the fibers, which have a relatively lower melting point, can be melted by setting the temperature of the heated air to a temperature which is higher than the melting point of the fibers with a relatively lower melting point, and is lower than the melting point of the fibers with a relatively higher melting point, so that the fibers with the relatively higher melting point, can be bonded among each other at their intersections, with the melted fibers with the lower melting point acting as bonding agent, to effect a continuous fibrous aggregate
650
, which has a predetermined thickness.
(2-b) Mold Based Method
FIG. 13
is a drawing for depicting one of conventional methods for forming a fibrous aggregate. A block of multilayered fibrous material
610
is identical in material to the continuous multilayered fibrous material
600
used in the heated air conveyer heating chamber based method, except that it is in the form of a block. More specifically, as shown in FIG.
13
(
a
), the multilayered fibrous material block
610
comprises several layers of fibers, in which fibers are aligned approximately in parallel in a certain direction a, and which are stacked in a direction b perpendicular to the direction in which the fibers are aligned in each layer. This multilayered fibrous material block
610
is placed in an aluminum mold
700
, and is covered with a lid
710
as shown in FIGS.
13
(
b
) and (
c
). At this stage, the multilayered fibrous material block
610
in the mold
700
has been simply compressed in the stacking direction b, in the mold
700
. Then, a block of fibrous aggregate is obtained by heating the mold
700
until the aforementioned condition is satisfied.
However, the above described methods for forming a fibrous aggregate block have such problems of their own that will be described below.
(1) Needle Punching Method
A needle punching method physically causes fibers to entangle, with the use of a felting needle. Therefore, a fibrous aggregate produced by a needle punching method is hard, thin, and high in bulk density. In other words, a s
Hase Tetsuya
Kitabatake Kenji
Morita Haruo
Nakamura Masao
Shimizu Eiichiro
Fitzpatrick ,Cella, Harper & Scinto
Inoac Corporation
Lechert Jr. Stephen J.
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