JP4429249B2 - Processing method for elastic members - Google Patents

Description

  The present invention relates to a method for processing an elastic member.

In the production line of absorbent articles such as panty liners, sanitary napkins, incontinence pads, etc., when a belt-like stretchable member is continuously transported, the stretchable member should not be stretched without applying transport resistance as much as possible. Even if transport is performed as described above, the stretchable member is stretched in the flow direction due to the rotational resistance and frictional resistance of the free roll. In addition, even when the tension of the stretchable member drawn out from the roll-shaped raw material is controlled to be constant during the transfer using a dancer roll, mechanical loss such as a free roll (sliding resistance of a rotating shaft support such as a bearing) Thus, the stretchable member is stretched by the generic name of the force that makes it difficult to turn the freeroll.
For this reason, when processing the pasting, cutting, printing, etc. of other sheet materials to the stretchable member after being transported to some extent, it is introduced into the processing device in a stretched state. Therefore, inconveniences such as phase shift and variation in cut length occur, which may adversely affect subsequent processes and final products. In addition, when another sheet material is bonded to the stretchable elastic member and then cut, the stretched elastic member contracts to cause wrinkles in the other sheet material, and the product There was a problem that the quality deteriorated or it became a defective product.

  As a technique related to the conveyance of the sheet material, a method is known in which the sheet material is conveyed while being adsorbed by a so-called vacuum conveyor. For example, Patent Document 1 describes a sheet conveying device that travels an endless conveying belt in which suction holes are arranged and places a sheet on the conveying belt for suction conveyance. However, when a belt-shaped stretchable member is conveyed using a vacuum conveyor, the stretchable member is restrained from being stretched on the vacuum conveyor, but the stretchable member may be stretched before and after that. . Further, the vacuum conveyor has a complicated structure. For example, a manufacturing facility for manufacturing an absorbent article using a band-shaped stretchable member is complicated, and there is a problem that the manufacturing cost is increased.

JP 7-309474 A

Accordingly, an object of the present invention is to provide a method for processing a stretchable member that does not require complicated equipment and can process the stretchable member in a state in which the stretch of the stretchable member is suppressed. .

  The present invention continuously conveys a belt-shaped stretchable member and introduces it into a processing apparatus, and in the processing apparatus, processes the stretchable member to perform predetermined processing on the stretchable member while transporting the stretchable member. In the method, by means of an overfeed device arranged immediately before the processing device, the stretchable member is sent out at a speed higher than the conveying speed of the stretchable member when processing by the processing device, and on the upstream side of the overfeed device The above-mentioned object is achieved by providing a method for processing an elastic member that introduces and processes an elastic member in a state in which the degree of extension is less than that of the elastic member into the processing apparatus. is there.

According to the method for processing an elastic member of the present invention, the elastic member can be processed in a state where expansion of the elastic member is suppressed without requiring complicated equipment .

Hereinafter, the present invention will be described based on a preferred embodiment thereof with reference to the drawings.
FIG. 1 shows an example of a production line for manufacturing a panty liner having a configuration in which a liquid holding layer made of a stretchable material and a leak-proof layer made of a non-stretchable material are laminated and both layers are joined to each other at the peripheral edge. The parts are shown. The panty liner is used with the liquid retaining layer side directed toward the wearer's skin side and the leak-proof layer directed toward the underwear side such as shorts. The liquid can be held so as not to leak.

In the processing method of this embodiment, as shown in FIG. 1, the belt-like stretchable member 1 which is a material for forming the liquid retaining layer of the panty liner is continuously fed out from the roll-shaped raw fabric 10 and its stretchability is obtained. The member 1 is transported by the transport unit 2 in which a plurality of free rolls (rolls that come into contact with the transported strip material and rotate in conjunction with the movement of the strip material) 21 to 24 are disposed , and transported by the transport unit 2 The stretchable member 1 after being introduced is introduced into the processing device 3, and the processing device 3 performs predetermined processing on the stretchable member 1 while transporting the stretchable member 1.

The processing apparatus 3 in this embodiment is a bonding apparatus including a pair of nip rolls 31 and 32, and a hot melt adhesive is applied to one surface of a strip-shaped non-stretchable member 33 that is a material for forming a leak-proof layer of a panty liner. The member 33 after the hot melt adhesive 35 is applied by the coating machine 34 is laminated on the stretchable member 1 introduced into the processing apparatus 3, and the upper and lower surfaces of the laminated body are paired with a pair of nip rolls 31, 31. The non-stretchable member 33 is bonded to the stretchable member 1 by narrowing the pressure between 32.
The pair of nip rolls 31 and 32 of the processing apparatus 3 are driven to rotate by a servo motor (not shown). In the processing method of this embodiment, the nip rolls 31 and 32 are rotated at the same peripheral speed V1. Thereby, the non-stretchable member 33 is bonded to the stretchable member 1 transported at the speed V1.

In the present embodiment, as shown in FIG. 1, an overfeed device 4 is disposed immediately before the processing device 3. The overfeed device 4 includes a pair of nip rolls 41, 42, and both rolls 41, 42 rotate in the direction of the arrow in the figure with the stretchable member 1 sandwiched between the pair of nip rolls 41, 42. Thus, the stretchable member 1 can be sent out toward the downstream side, that is, the processing apparatus 3 side at the same speed V2 as the peripheral speed V2 of both the rolls 41 and 42.
In the processing method of the present embodiment, the delivery speed V2 of the stretchable member 1 by the overfeed device 4 is made faster than the transport speed V1 of the stretchable member 1 in the processing device 3.
Thereby, it is possible to reduce the degree of expansion of the stretchable member 1 that has been stretched in the conveyance path 2 and the like. It is possible to prevent seal phase shift, product cut length variation and the like during processing. Further, after the laminate 5 in which the non-stretchable member 33 is bonded to the stretchable stretchable member 1 is subjected to a known process such as a sealing process for sealing the peripheral portion, and then cut into individual panty liners, A large number of wrinkles as shown in FIG. 3 occur on the non-skin contact surface constituted by the non-stretchable member 33 due to the contraction of the stretchable member 1, but the degree of expansion is reduced as in this embodiment. By introducing the elastic member 1 into the processing apparatus, it is possible to prevent or remarkably reduce the occurrence of such wrinkles.

The ratio of the feeding speed V2 by the overfeed device 4 to the transport speed V1 of the elastic member 1 in the processing device 3 is determined by the elastic member 1 immediately before being introduced into the processing device when the overfeed device 4 is eliminated. Although it can be appropriately determined according to whether it is extended to some extent, and is not particularly limited, for example, the delivery speed V2 can be 100.5% to 400% of the transport speed V1, It is preferable to be 100.5% to 300% of the conveyance speed V1.
The distance from the processing device 3 to the overfeed device 4 is 100 to 1000 mm, preferably 300 to 500 mm. If this distance is too close, the stretched stretchable member is difficult to return between the overfeed device 4 and the processing device 3, and if the distance is too long, the stretchable member tends to sag due to its own weight.

In the present embodiment, a strip of multilayer nonwoven fabric having the structure shown in FIG. 2 is used as the stretchable member 1, and a strip formed of a resin film such as a polyethylene film, a polypropylene film, or a polyester film is not stretched. It is used as the sex member 33.
The multilayer nonwoven fabric shown in FIG. 2 includes a first fiber layer 11 containing latent crimpable fibers and a latent crimpable fiber that contains no latent crimpable fibers or a lower content than the first fiber layer 11. It consists of a second fiber layer 12, and the first fiber layer 11 and the second fiber layer 12 are integrated by a joint portion 13 that is partially formed by being dispersed in the plane direction. An uneven shape is formed on the second fiber layer 12 side of the multilayer nonwoven fabric. This multi-layer nonwoven fabric has a first fiber layer forming material and a second fiber layer forming material laminated to each other, and is partially heat-sealed by heat or ultrasonic embossing, etc. After the intermediate formed in a dispersed state is manufactured, the intermediate is subjected to a heat treatment, and the first fiber layer forming material is thermally contracted. Has elasticity derived from. The latent crimpable fiber is a fiber that can be handled in the same manner as a conventional nonwoven fabric fiber before heating, and has a property that a helical crimp is developed and contracted by heating at a predetermined temperature.

  The latent crimpable fiber includes, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates as components. Examples of the thermoplastic polymer material include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, and polyamides. The content of the latent crimpable fiber is preferably 40 to 100% by weight, more preferably 70 to 100% by weight, based on the weight of the liquid holding layer 2. This multilayer nonwoven fabric is laminated and bonded to the non-stretchable member 33 with the first fiber layer 11 side facing the non-stretchable member 33 side.

In the processing method of the present invention, it is preferable that a tension control means for keeping the tension of the stretchable member 1 constant is arranged between the feeding portion 1A of the stretchable member 1 and the overfeed device 4. For example, as shown in FIGS. 4 and 5, at least one dancer roll 25 can be disposed between the feeding unit 1 </ b> A and the processing device 3. The dancer roll 25 is preferably arranged at a position immediately after unwinding.
By keeping the tension of the elastic member 1 to be transported constant before the overfeed device 4, a constant overfeed amount can be obtained, thereby enabling more stable overfeed transport. .

Further, in the processing method of the present invention, a monitoring means for the degree of expansion of the elastic member is provided on the downstream side of the overfeed device 4, and the overfeed device 4 sends out according to the degree of expansion of the elastic member. It is preferable to adjust the speed V2. As a means for monitoring the degree of expansion of the elastic member, as shown in FIG. 4, it is disposed between the overfeed device 4 and the processing device 3,
A width sensor 71 that continuously or intermittently detects the width of the elastic member, and the degree of expansion of the elastic member is determined from the width of the elastic member detected by the width sensor 71, and according to the degree, Examples include those provided with a calculation unit 72 that outputs a signal for accelerating / decelerating the feed speed of the feed device 4 to the overfeed device 4.
In the overfeed device 4 in the embodiment shown in FIGS. 1 and 4, the pair of rolls 41 and 42 are driven by the servo motor 43, and such control is easy. In addition, by performing such control, the elastic member can be handled with higher accuracy.

As one method for accelerating / decelerating the delivery speed of the overfeed device 4 in accordance with the degree of expansion of the elastic member, a width corresponding to a preferable degree of extension is set as a reference value and detected by a width sensor. When the width is wider than the reference value, the delivery speed V2 by the overfeed device 4 is decelerated, and when the width is narrower than the reference value, the delivery speed V2 by the overfeed device 4 is increased. The width set as the reference value is preferably set so as to be the sheet width at the minimum tension at which the sheet can be conveyed without meandering.
As the width sensor, a one-dimensional laser sensor or a line sensor may be used, or a two-dimensional image sensor may be used. For example, the calculation unit 72 converts data (for example, image data) obtained from the width sensor into speed data by an internal controller and sends a signal to the servo motor.

If the stretchable member is accelerated rapidly only by the pair of nip rolls (feed rolls) 41 and 42 of the overfeed device, the sheet contraction may not be in time and sheet sagging may occur. In particular, in the case of a super flexible material, the overfeed amount [overfeed amount = (feeding speed V2 by overfeeding device / conveying speed V1 in processing device) × 100] may be 400% or more. May occur.
As a method for solving such a problem, as in the embodiment shown in FIG. 5, overfeed devices 4A to 4C having a pair of nip rolls 41 and 42 are provided in multiple stages along the conveyance path, and are farthest from the processing device. It is preferable to change the delivery speed (feed speed) from the device 4C toward the nearest device 4A so as to gradually decrease. In particular, it is preferable to set the feed speed V2 of the overfeed device 4A closest to the processing apparatus to 105% or less of the transport speed V1 in the processing apparatus 3.

The feed speeds V2, V3, V4 of the overfeed devices provided in multiple stages are feedback-controlled for the feed speed V2 of the overfeed device 4A closest to the processing device, based on the width of the stretchable member using the width sensor 71, for example. The feed speed V3 of the upstream overfeed device 4B is determined so as to be a predetermined ratio (feed ratio) with respect to the speed V2, and further, the upstream speed is set so as to be a predetermined ratio with respect to the speed V3. It is preferable to determine the delivery speed V4 of the overfeed device 4C. The feed ratio is preferably determined within 150% with respect to the upstream overfeed device. Examples of the feed ratio include V2 / V1 = 105%, V3 / V2 = 150%, and V4 / V3 = 150%. can do.
In FIGS. 4 and 5, the same elements as those in FIG. 1 or 4 are denoted by the same reference numerals.

As mentioned above, although embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the meaning of this invention.
For example, the belt-like stretchable member used in the present invention includes a stretchable member having one or more layers containing latent crimpable fibers crimped three-dimensionally, such as the multilayer nonwoven fabric described above, as well as physiological Various elastic members conventionally used in the manufacture of absorbent articles such as napkins, panty liners, disposable diapers, etc. can be used, and various elastic members used in other than the manufacture of absorbent articles Can also be used. The belt-like stretchable member only needs to have stretchability in at least the flow direction, and even if it has stretchability in both the flow direction and the direction orthogonal to the flow direction, it is stretchable only in the flow direction. It may have.

The processing apparatus according to the present invention may be a laminating apparatus for laminating a non-sheet material, for example, a thread-like elastic member, to a stretchable member instead of a laminating apparatus for a sheet material to a stretchable member. The cutting device which cuts a property member into predetermined length may be sufficient.
As a cutting device, an elastic member is introduced between a cutter roll having a cutting blade formed on the peripheral surface and an anvil roll that receives the cutting blade of the cutter roll, and the elastic member is arranged at a predetermined interval in the width direction. And a device that cuts the stretchable member into a predetermined shape. Even in this case, it is possible to prevent or reduce the deviation of the cut position.
As the processing apparatus, for example, a sealing apparatus, for example, an uneven roll and a smooth surface roll, an apparatus for clamping a stretchable member between both rolls and sealing a predetermined portion of the stretchable member, and various known methods It may be a printing device or the like.

  The overfeed device according to the present invention includes a pair of nip rolls 41 and 42 and two or more drive rolls arranged in the vicinity of each other to increase the contact angle of the sheet with the roll to give a driving force. Things can also be used. In addition, as an overfeed device, a device in which two belt-type conveyance devices in which an endless belt is installed between a drive roll driven by a servo motor or the like and a driven roll are combined with the belt portions facing each other is used. In addition, it is also possible to use a material in which an elastic member is sandwiched between the belts of both belt type conveying devices and the elastic member is sent out at a predetermined speed. Further, when the overfeed devices are arranged in multiple stages, two stages or four or more stages can be arranged instead of arranging three stages as shown in FIG.

  Also in the roll method, the overfeed efficiency may be increased by using a vacuum means to positively attract the surface of the roll to increase the grip force and make it difficult to slip. The acceleration / deceleration of the overfeed roll is not limited to the servo motor, and may be performed by a mechanical continuous transmission represented by a belt type or a traction type. In the above-described embodiment, the stretchable member 1 is fed out from the roll-shaped original fabric 10 by the surface driving type feeding mechanism. However, the elastic member 1 can be fed out by the shaft driving type feeding mechanism.

  In addition, the transport of the stretchable member on the upstream side of the overfeed device is a belt-type transport device disposed only on one side of the stretchable member, and the stretchable member is sandwiched between a pair of endless belts. It can also be carried out by a belt type carrying device or the like for carrying, and can also be carried out by various conventionally known carrying devices.

It is a perspective view which shows the process sequence of the elastic member in one Embodiment of this invention. It is sectional drawing which shows the cross section of the thickness direction of the elastic member used by one Embodiment of this invention. It is a top view which shows a part by the side of the non-skin contact surface of the panty liner obtained by the conventional processing method. It is a perspective view which shows the process sequence of the elastic member in other embodiment of this invention. It is a perspective view which shows the process sequence of the elastic member in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Strip-shaped elastic member 2 Conveying part 3 Bonding apparatus (processing apparatus)
4 Overfeed device

Claims (6)

In a processing method of a stretchable member that continuously conveys a belt-shaped stretchable member and introduces it into a processing apparatus, and performs predetermined processing on the stretchable member while transporting the stretchable member in the processing apparatus,
With the overfeed device arranged immediately before the processing device, the elastic member is sent out at a higher speed than the conveying speed of the elastic member when processing with the processing device, and the elasticity on the upstream side of the overfeed device Rutotomoni reduce the degree of expansion than the degree of expansion of the member, processing method stretchable member stretchable member in that state, machining is introduced into the processing apparatus.   The stretch member processing method according to claim 1, wherein the overfeed device is driven by a servo motor. Wherein placing a sensor for detecting the width of the stretchable member between the overfeed unit and the processing apparatus, the width detected by the sensor, is wider than a predetermined reference value, delivery speed by the overfeeding device The method for processing a stretchable member according to claim 1 or 2, wherein when the speed is lower than the reference value, the feeding speed by the overfeed device is increased.   The processing method of the elastic member in any one of Claims 1-3 which provides an overfeed apparatus in multistage along a conveyance path.   The method for processing a stretchable member according to claim 4, wherein the feed rate is gradually decreased from an overfeed device far from the processing device toward a close overfeed device.   The method for processing a stretchable member according to claim 4, wherein the feed speed of the overfeed device arranged upstream thereof is determined according to the feed speed of the overfeed device closest to the processing device.

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