Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2002-01-03
2004-11-02
Yao, Sam Chuan (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S214000, C156S285000, C264S101000, C264S257000, C264S571000
Reexamination Certificate
active
06811642
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a production method for an absorbent article (body) used for pet sheets, disposable diapers, sanitary napkins, and the like.
BACKGROUND OF THE INVENTION
Conventional production methods for producing absorbent bodies are explained with reference to
FIGS. 13 and 14
.
In the conventional production method of an absorbent body shown in
FIG. 13
, a carrier tissue
2
is drawn from a roll
2
a
which is supported by an axis
1
and is forwarded continuously. A pulp supplier
3
is provided above the carrier tissue
2
which is forwarded continuously. Crushed pulps are supplied from the pulp supplier
3
to be poured on the carrier tissue
2
. A supply nozzle
4
for supplying particulate SAP (super-absorbent polymers) is provided above the carrier tissue
2
, and supplies the SAP on the carrier tissue
2
which is forwarded continuously.
A suction chamber
6
is provided opposite the pulp supplier
3
and the supply nozzle
4
with the carrier tissue
2
interposed. Crushed pulp and the SAP are sucked by the suction chamber
6
to form a strip of an absorbent material layer
5
comprised of a mixture of crushed pulp and SAP on the carrier tissue
2
.
For a faster production, crushed pulp and SAP are continuously supplied onto the carrier tissue
2
to form a strip of an absorbent material layer
5
. Thereafter, a cover tissue (not shown) is supplied onto the strip of the absorbent material layer
5
to form a laminated body, which comprises the carrier tissue
2
, a cover tissue and the absorbent material layer
5
interposed between the tissues. Both sides of the laminated body are then cut by a cutter, such as a rotary cutter, and thereafter the laminated body is cut into individual absorbent bodies.
In the conventional production method of an absorbent body shown in
FIG. 14
, the carrier tissue
2
drawn from the roll
2
a
is forwarded continuously. A circular pattern drum
7
is provided above the carrier tissue
2
which is forwarded continuously. The pattern drum
7
rotates in the clockwise direction around the axis
8
at the running speed of the carrier tissue
2
.
Concavities
9
are provided on the outer face of the pattern drum
7
at predetermined intervals. Mesh
9
a
of a predetermined screen dimension is provided at the bottom of the concavity
9
. The concavity
9
is formed in a predetermined shape such as the shape of an hourglass. A pulp supplier
11
is provided above the pattern drum
7
, facing the outer surface of the pattern drum
7
. A supply nozzle
12
for supplying SAP is provided also facing the outer surface of the pattern drum
7
.
According to the production method of the absorbent body as shown in
FIG. 14
, crushed pulp is supplied from the pulp supplier
11
into the concavity
9
which is provided on the outer surface of the rotating pattern drum
7
. Also, SAP is supplied from the nozzle
12
into the concavity
9
in the same manner.
A suction means is provided inside of the pattern drum
7
facing the pulp supplier
11
and the supply nozzle
12
for sucking air through the openings of the mesh
9
a
provided at the bottom of the concavity
9
. The crushed pulps and the particulate SAP are sucked onto the concavity
9
, thereby forming an absorbent material layer
13
having the same shape as the concavity
9
.
At the time the concavity
9
faces the carrier tissue
2
during the course of rotation of the pattern drum
7
, another suction means provided below the carrier tissue
2
sucks air through the carrier tissue
2
. By this suction, the absorbent material layer
13
is transferred onto the carrier tissue
2
. Subsequently, a cover tissue (not shown) is laid along the carrier tissue
2
and the absorbent material layer
13
, thereby forming a laminated body comprised of the carrier tissue
2
, the cover tissue and the absorbent material layer
13
interposed between the tissues. Thereafter, the carrier tissue
2
and the cover tissue are cut in accordance with the shape of the absorbent material layer
13
to produce individual absorbent bodies.
In high speed production of the absorbent body, according to the conventional production method shown in
FIG. 13
, because the absorbent material layer
5
is formed in a strip shape on the carrier tissue
2
in a continuous process, a rectangular absorbent body is produced. However, it is almost impossible to produce an absorbent body having a desired shape, such as an hour glass shape. Therefore, in order to produce an absorbent body having a desired shape, e.g., hour glass shape, it is necessary to perform a trimming process to such laminated body in a press working process. However, this results in many additional processing steps.
In addition, in order to laminate another absorbent material layer on the absorbent material layer
5
formed by the conventional production method shown in
FIG. 13
, crushed pulp and SAP must be sucked by the suction means through the carrier tissue
2
and the absorbent material layer
5
. However, due to the poor air permeability of the laminated layers formed from the carrier tissue
2
and the absorbent material
5
, it is almost impossible to form another absorbent material layer over the laminated body by sucking additional crushed pulp or SAP by the suction means. For this reason, in the production of the absorbent body having two absorbent material layers laminated, each of the absorbent material layers must be produced separately by the method shown in FIG.
13
and each laminated thereafter. Therefore, conventional methods inevitably use many production steps to produce an absorbent body having two absorbent material layers therein.
Moreover, in order to cut an absorbent body having two laminated absorbent material layers therein, another cover tissue must to be laid over the absorbent material layer at the upper side. Consequently, at least three tissue layers are needed, making the production of the absorbent body expensive.
On the other hand, according to the conventional production method of the absorbent body shown in
FIG. 14
, the absorbent material layer
13
can be formed in the same shape as that of the concavity
9
formed on the outer face of the pattern drum
7
.
However, in order to form the absorbent material layer
13
in the same shape as that of the concavity
9
, crushed pulp and particulate SAP must be sucked into the concavity
9
by the suction force through the openings of the mesh
9
a
provided at the bottom of the concavity
9
. In general, the opening size of the mesh
9
a
is 60 mesh (according to the standard of Tyler, U.S.A. the opening size of such mesh is equal to 0.246 mm).
However, because of the fineness of the SAP supplied to the concavity
9
, SAP easily passes into the inside of the pattern drum
7
through the mesh
9
a
, thereby rendering a very poor yield ratio of SAP. Due to the passage of SAP through the mesh
9
a
, which results in a poor yield ratio of SAP, it is very difficult to increase the content of SAP in the absorbent layer
13
. Therefore, it is extremely difficult to produce an absorbent layer containing 20% SAP or more by weight.
Further, in order to accelerate the liquid absorption speed of the absorbent material layer, the particle size of SAP present in the absorbent material layer must be very small. However, the mesh
9
a
having the opening size of 60 mesh can hardly prevent such fine SAP from passing through into the pattern drum
7
. Therefore, it is almost impossible for the mesh
9
a
to hold SAP having a small particle size, such as 100 mesh or less (which passes through a mesh having an opening size of 0.147 mm) at the concavity
9
.
In addition, according to the conventional production method shown in
FIG. 14
, the absorbent material layer
13
must be sucked through the carrier tissue
2
by the suction means provided below the carrier tissue
2
at the time the concavity
9
faces the carrier tissue
2
. However, in order to suck the absorbent material layer formed in the concavity
9
through the carrier tissue
2
, a very stron
Darby & Darby
Unicharm Petcare Corporation
Yao Sam Chuan
LandOfFree
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