JP3210699B2 - Method for forming fluffy pads for diapers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for forming and bonding fluffy or fluffy pads for diapers, and more particularly to a method using an annular drum, wherein one suction is used. The invention relates to a method for both forming and thermally bonding pads on a formula drum.

Drums for forming fluff or fluff are described, for example, in US Pat. No. 3,599,293 of the applicant.
It has been known for quite some time, as can be seen in the specification. Furthermore, although the method of forming the pad and the method of thermal bonding are existing technologies, there is no example in which both methods are performed with a single drum.

[0003] The manufacturing advantages provided by the present invention of performing both of the above methods on a single drum are significantly greater than when both methods are performed separately. That is, the advantage is that the shape of the pad can be maintained. Diaper manufacturers have made great efforts in forming pads shaped to have optimal performance for receiving waste. However, in the process of removing the pad from the forming drum, the shape is damaged. Therefore, in the joining step, the pad that has not solidified at that time is further distorted.

[0004] An important operational advantage is that the flow of the air (which forms and bonds the pads) is split on the drum, thus providing better control of these air flows. These advantages (and other advantages) are described in more detail below.

[0005] 1. Pad removal: The fluffy mixture of synthetic material allows the pad to be removed very cleanly from the forming form due to the increased bondability.

[0006] 2. Pad integrity: The initial formation is not disturbed by handling since the pads are bonded in the forming mold. This can maximize fiber entanglement and maximize bonded fiber area. It will be appreciated that handling such as bending, spreading or compressing the pads tends to eliminate the fiber bonds obtained in the forming process.

[0007] 3. Mechanism simplification: 1 for both methods
Since two drums are used, an intermediate moving mechanism is omitted.

[0008] 4. Cost savings: According to the method of the present invention, the thin leaf wrap normally present to assist in transporting the pad to the final product, i.e., a position for insertion into a disposable diaper, sanitary pad or the like, is provided. Can be omitted.

[0009] The basic method involves converting wood pulp and other fibrous materials and bonding polyolefins into fibers that are suspended in the air via a hammer mill or other fiberizing device. The suspended fibers, the so-called fluffy mixture, are then collected on the surface of a screen, which allows air to pass through but retains the fluffy mixture.

This screen is made of a woven material or other porous material, has a region largely open to the flow of air, and is formed into a desired pad shape.
This screen area or pocket means is supported by a rotating drum through which air is exhausted.

[0011] The formation of the pad includes the attachment of a fluff mixture,
This is done by several steps consisting of other attachments, such as superabsorbents, and scarfing. Scarfing refers to the process of brushing the outer surface of a newly formed pad with a rotating brush roller or similar surface. These steps are repeated to form multiple layers of material on the pad.

Thereafter, the formed pad is moved to a region where high-temperature air is guided to the pad and discharged from the inside of the drum.
It is rotated on the drum. At least a portion of the pad includes synthetic fibers, such as polyolefin fibers, that have a lower melting point than natural (wood) fibers that make up the majority of the pad. By heating the pad above the melting point of the synthetic fiber and below the melting point of the wood fiber, the synthetic fiber is brought into a molten state, and the wood fiber can be covered. After heating to the bonding temperature, the pad is cooled, thereby solidifying the molten material and bonding the fibrous structures together, providing the advantages outlined above. It should be noted that simultaneous formation and bonding on a forming drum in order to form a diaper pad without distortion is a conventional technique, i.e., U.S. Pat. No. 3,051,369,
No. 3,619,322, 3,939,240, 4,592,708 and 4,666,647 are not disclosed.

[0013] Other advantages and objects of the present invention will become apparent from the following detailed description.

[0014]

DETAILED DESCRIPTION First, referring to FIG.
Numeral 10 generally indicates a pad forming drum, and a plurality of pockets (pocket means) 11 are arranged at regular intervals in a circumferential direction on an outer peripheral surface thereof. Usually, the diameter of this drum 10 is about
It is 2.5-3m (8-10ft.). In the figure, the drum 10
Is shown to have one pocket 11 at a constant width for simplicity. However, multiple pockets 11
May be arranged in an axially aligned relationship. A spider 12 is provided on one side of the drum 10, and serves as a means for connecting a transmission 13 (see FIG. 3) for rotating the drum 10.

Referring again to FIG. 1, a pulp mixture comprising polyolefin and wood fiber, as shown at 14,
It is designed to be introduced into the hammer mill 15. The hammer mill 15 is rotated by a motor 16 via a transmission 17. The fiberized fluff mixture, indicated by arrow 18, passes through conduits 19, 20 and extends partially around drum 10 and defines a sector portion (hereinafter "sector-defining plenum") 21, Sent to 22. Also, heated air is introduced through the sector defining plenums 23, 24, and the formed pads P are removed from the drum 10 onto the conveyor 26 under the vacuum created by the vacuum box 25. Thereafter, the pad P is coated between the nonwoven web 27 and the polyethylene web 28.

After the pad P is removed, the empty pocket 11 is cleaned in the vacuum hood 30 by air sucked radially outward as indicated by reference numeral 29. The pipe 31 is connected to a vacuum source (not shown). Immediately after cleaning, the release powder is applied to the empty pocket 11 through the plenum 32.

The following embodiments of the present invention are believed to be helpful in understanding the present invention.

[0018]

EXAMPLE In this example, the web 14 (see the left part of FIG. 1) 14 is a pulp mixture consisting of 85% wood fibers and 15% olefins and is approximately 1089 kg / hour (24 hours).
00lb.). A suitable pulp mixture is available from Hercules, Inc. under the trade name "PULPEX E-338".
Available at As shown schematically at 33, air at room temperature, ie, 70 ° F. (21.1 ° C.), is also drawn into the hammer mill 15 in a quantity of 3000 CFM.

The first layer of material located within the pocket 11 is a fluff release agent delivered from the sector defining plenum 32, which layer is schematically indicated at 34 in FIG. . Next, the fluff mixture transferred into the sector defining plenum 21 in the conduit 19 is arranged to form a layer 35, while air is exhausted through the exhaust port 36. The first layer 35 is subjected to a surface treatment (scarfing) as indicated by reference numeral 37.

The first layer 35, as indicated by reference numeral 38,
Approximately 320 entering the sector definition plenum 23 at a flow rate of approximately 1000 CFM
Joined by heated air at 160 ° F (° F). This air is
It is discharged from port 39 at approximately 210 ° F (98.9 ° C).
Next, a layer of superabsorbent powder, indicated schematically at 40 in FIG. 2, is placed in the area covered by the plenum 41.

A second fluff mixture layer 42 (see FIG. 2) is placed through plenum 22 and air is exhausted through port 43. Then, as shown by reference numeral 44, 1000
Coupling is accomplished by heated air flowing into the plenum 24 at a temperature of 350 ° F at a CFM flow rate and exiting the port 45 at a temperature of about 250 ° F.

Cooling air is directed to the last sector portion 46 of the forming drum 10 and is exhausted through a port 47.

[0023]

Referring to FIG. 3, it can be seen that the forming drum 10 is supported on a frame designated generally by the reference numeral 48. The frame 48 has a horizontal tubular body 49 removably clamped thereto, which rotatably supports a shaft 50 on which the spider 12 is mounted. Further details of the construction of the drum 10 are described in U.S. Pat. No. 4,995,141.

The spider 12 supports a ring 51, a plurality of pad forms 52 (defining the pockets 11), and a second ring 53 passing through the pad form 52 (see also FIG. 4). ).
Therefore, the inner second ring 53 is connected only to the ring 51 via the plurality of arc-shaped pad molds 52.
On both sides of the pad form 52, clamps 54 for integrally fixing the rings 51 and 53 are provided (the left part in FIG. 3).

Within the drum 10, and more particularly, inside the axially spaced rings 51, 53, there is provided an immobile plenum, generally designated by the numeral 55. This is fixed to the frame 48 and has a sealing relationship with the rings 51 and 53 of the drum 10.

More specifically, the inner plenum 55 comprises a generally cylindrical structure defined by rings 56, 57, which are formed by a laterally extending member 58 and a radially extending member. The members 59 and 60 extending in the directions are integrated. As shown by reference numeral 61, an annular plate closing the plenum is attached to the inside of the rings 56 and 57,
This plate is advantageously composed of a transparent material such as plexiglass. Furthermore, the sector formation plate
62 is provided inside the radial members 59, 60 and the axial member 58.

Here, referring to FIG. 1, as indicated by reference numeral 62, it can be seen that a plurality of sector forming plates are provided. Accordingly, a sector-shaped chamber is provided for each of the outer plenums 21 to 24, 29, 32. No plenum is required to reduce the room temperature cooling air 46 that is drawn under the influence of the exhaust port 47.

[0028]

First, a web 14, preferably made of wood pulp and polyolefin, is introduced into a hammer mill 15. Also, room temperature air is sucked into the hammer mill as indicated by reference numeral 33, and at the same time, the fluff mixture is delivered to the plenums 21 and 22. The fibers are deposited in the pockets 11 (see FIG. 4), and air is discharged radially inward under the plenum 21 through the flow ports 36.

Next, heated air for performing the coupling function is introduced through the plenum 23 and then discharged from the port 39. Superabsorbent powder may be added to plenum 41 at this stage to form layer 40 (see FIG. 2).

The second fluff mixture layer 42 comprises a plenum.
It is formed by fibers ejected from 22 and discharged from exhaust port 43. Bonding of these fibers is performed by heated air flowing radially inward from the plenum 24. Thereafter, the pad P is cooled by cooling air, as indicated by reference numeral 46, and under the influence of vacuum, as indicated by reference numeral 25, on the conveyor 26.
And further processed by a nonwoven web 27 and a polyethylene web 28 and the like. After this, pocket 11
Is cleaned by air 31 flowing radially outward into plenum 29 under the influence of a vacuum. The empty pocket 11 is covered with a release material by a plenum 32 (see FIG. 2).

While one embodiment of the present invention has been described in detail for purposes of illustration, those skilled in the art can make various modifications to the details without departing from the spirit and scope of the invention.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a pad forming drum device configured according to the present invention.

FIG. 2 is an enlarged sectional view schematically showing one of the diaper pads of FIG.

FIG. 3 is an end view showing the apparatus of FIG. 1;

FIG. 4 is an exploded perspective view schematically showing a pad forming drum of the apparatus of FIG.

[Explanation of symbols]

 10 Pad-forming drum 11 Pocket 14 Web of fluff mixture 15 Hammer mill 18 Fluff mixture 21,22,23,24 Sector-defined plenum P-pad

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Gary E. Johnson Redovina Street, Green Bay, Wisconsin, United States of America 1646 (56) References Patent 2813819 (JP, B2) Patent 2541557 (JP, B2) Patent 2541558 (JP, B2) JP 8-29155 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01G 25/00 A61F 13/18 A41B 13/02

Claims (5)

(57) [Claims] An annular drum having a plurality of pad forming pocket means (11) circumferentially separated from each other on an outer peripheral surface thereof.
(10), and while the drum is being rotated, air containing synthetic material binder-added fluffy fibers (18) is passed through the first sector portion (21) of the drum in a radial direction of the outer peripheral surface. A method of forming an absorbent fluffy pad for diapers, comprising flowing inward and attaching said fluffy fibers in each of said pocket means (11), wherein the temperature is above the melting point of the synthetic material binder. The second sector following the first sector portion (21) in the drum rotation direction.
The heated air is flowed radially inward of the drum through the sector portion (23) of the above, to thermally bond the synthetic material binder to integrate the fluffy fibers, and to remove the pad (P) from the drum. A method for forming a fluffy pad for diapers, characterized in that: 2. The method of claim 1, further comprising flowing air through a last sector portion (46) to cool the pad. 3. The method of claim 1, further comprising the step of scarfing the surface of the pad before exposing the pad to heated air. 4. In order to form a binder-free layer in said pocket means, first a release material is applied in a sector part (32) located before said first sector part (21). 2. The method for forming a fluffy pad for diapers according to claim 1, further comprising flowing air containing the diapers. 5. The method according to claim 1, wherein the attaching step (22) and the heating step (24) are repeated.