Apparatus for applying adhesive to stretchable members and stretchable composite sheet

Abstract

A stretchable composite sheet, wherein pleat-free regions where no pleats are formed are formed between a plurality of pleat formation regions, the sheet being made by a method, wherein non-continuous coating sections are set so as to correspond to form the plurality of pleat formation regions, and non-coating sections are set so as to correspond to form the pleat-free regions, and an intermittent coating is performed on stretchable elastic members (rubber threads). An apparatus for non-continuously and intermittently applying a hot-melt adhesive comprises an intermittent coating unit, which includes a hot-melt supply control device having a valve mechanism and a coating head having slit grooves in which coating areas are formed, and a non-continuous coating unit, which vertically vibrates rubber threads, passing through the coating areas, between a coating position and a non-coating position.

Claims

1. An apparatus for applying an adhesive to stretchable members, comprising: a coating head that has slit grooves in which coating agent reservoirs are formed and is configured to apply an adhesive over an entire peripheral surface of rubber threads passing through the coating agent reservoirs; and a rubber thread vertical drive device that has slit grooves and is configured to move the rubber threads passing through the coating agent reservoirs up and down between a coating position at which the rubber threads pass through the coating agent reservoirs and a non-coating position at which the rubber threads pass away from the coating agent reservoirs, wherein the rubber thread vertical drive device is a rotating cam body that has a plurality of protrusions around a peripheral surface thereof and is driven synchronously with a feeding speed of the rubber threads.

2. The apparatus for applying an adhesive to stretchable members according to claim 1, wherein: a plurality of protrusions are formed on part of the peripheral surface of the rotating cam body that constitutes the rubber thread vertical drive device.

3. The apparatus for applying an adhesive to stretchable members according to claim 1, wherein: the rotating cam body that constitutes the rubber thread vertical drive device is formed with a protrusion section that has a plurality of continuous two protrusions on part of the peripheral surface and a flat section that has no protrusions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A and FIG. 1B are overviews of an apparatus for applying an adhesive to a stretchable member according to a first aspect of the invention of the present application, wherein FIG. 1A is a front view thereof, and FIG. 1B is a top view thereof.

(2) FIG. 2A and FIG. 2B are overviews of an apparatus for applying an adhesive to a stretchable member according to a second aspect of the invention of the present application, wherein FIG. 2A is a front view thereof, and FIG. 2B is a top view thereof.

(3) FIG. 3A and FIG. 3B are overviews of an apparatus for applying an adhesive to a stretchable member according to a third aspect of the invention of the present application, wherein FIG. 3A is a front view thereof, and FIG. 3B is a top view thereof.

(4) FIG. 4A and FIG. 4B are overviews of an apparatus for applying an adhesive to a stretchable member according to a fourth aspect of the invention of the present application, wherein FIG. 4A is a front view thereof, and FIG. 4B is a top view thereof.

(5) FIG. 5 is a diagram illustrating an operation of coating timing of the present invention, in a front view similar to FIG. 1A.

(6) FIG. 6 is a front view showing likewise the non-coating timing.

(7) FIG. 7 is a perspective view of a coating head which is an example of a means for applying an adhesive to rubber threads.

(8) FIG. 8 is a side view of the same.

(9) FIG. 9 is a longitudinal cross sectional view taken along the line S9-S9 in FIG. 8.

(10) FIG. 10 is a longitudinal cross sectional view taken along the line S10-S10 in FIG. 8.

(11) FIG. 11A and FIG. 11B are illustrations of a stretchable elastic member (rubber thread) in an extended state and on which a non-continuous adhesive application has been made, wherein FIG. 11A is a top view thereof, and FIG. 11B is a detail vertical cross sectional view thereof at an adhesive application position.

(12) FIG. 12A and FIG. 12B are illustrations of a stretchable composite sheet in a state in which a nonwoven fabric is integrated above and below stretchable elastic members (rubber threads) which are in an extended state and on which a non-continuous adhesive application has been made, wherein FIG. 12A is a top view thereof, and FIG. 12B is an enlarged vertical cross sectional view thereof.

(13) FIG. 13 is a perspective view of a stretchable composite sheet.

(14) FIG. 14A and FIG. 14B are illustrations of a stretchable composite sheet in an extended state, wherein FIG. 14A is a top view thereof, and FIG. 14B is an enlarged vertical cross sectional view thereof.

(15) FIG. 15 is a perspective view of a stretchable composite sheet according to the third aspect of the invention of the present application.

(16) FIG. 16 is a perspective view of a known stretchable composite sheet disclosed in Patent Literature 1, which is partially cut away.

(17) FIG. 17 is a perspective view of a known stretchable composite sheet disclosed in Patent Literature 2.

BEST MODE FOR CARRYING OUT THE INVENTION

(18) An apparatus for applying an adhesive to a stretchable member according to the first aspect of the invention of the present application will now be described with reference to FIG. 1A and FIG. 1B. This apparatus is comprised of: a coating head 10 that has slit grooves 5 in which coating agent reservoirs Q are formed and that applies an adhesive HM over the entire peripheral surface of stretchable members (rubber threads) R passing through the coating agent reservoirs Q, and a stretchable member (rubber thread) vertical drive device 1 that moves the rubber threads R passing through the coating agent reservoirs of the slit grooves up and down between a coating position (FIG. 5) at which the rubber threads pass through the coating agent reservoirs and a non-coating position (FIG. 6) at which the rubber threads pass away from the coating agent reservoirs Q.

(19) The rubber thread vertical drive device 1 is constituted by a rotating cam body 30 that has a plurality of protrusions 31 on its peripheral surface. A guide roller 32 having guide grooves 33 for feeding the stretchable members (rubber threads) R is provided, and a drive roller 34 for feeding a nonwoven fabric F is provided on the downstream side of the feeding.

(20) An apparatus for applying an adhesive to a stretchable member according to the second aspect of the invention of the present application will now be described with reference to FIG. 2A and FIG. 2B. As in FIG. 1A and FIG. 1B, the rubber thread vertical drive device is constituted by a rotating cam body 30 that has a plurality of protrusions 31 on its peripheral surface.

(21) Also provided are a drive motor 36 for a drive roller 35 for feeding the stretchable members (rubber threads) R, and a servo control mechanism 38 for a drive motor 37 for the rotating cam body 30, so that the feeding speed of the rubber threads and rotational speed of the rotating cam body 30 are synchronized.

(22) An apparatus for applying an adhesive to a stretchable member according to the third aspect of the invention of the present application will now be described with reference to FIG. 3A and FIG. 3B. A plurality of protrusions 31 are formed adjacently on part of the peripheral surface of the rotating cam body 30 that constitutes a rubber thread vertical drive device B.

(23) In the embodiment shown in FIG. 3A and FIG. 3B, the protrusions 31 are adjacent to each other over a range of 2/6 of the entire peripheral surface of the rotating cam body 30, and they are not provided over the rest of the peripheral surface range, resulting in that at least one pleat is formed by one rotation of the rotating cam body 30.

(24) An apparatus for applying an adhesive to a stretchable member according to the fourth aspect of the invention of the present application will now be described with reference to FIG. 4A and FIG. 4B. A characteristic feature thereof is that an intermittent coating is performed to form coating sections TT and non-coating sections NN, and the apparatus is comprised of an intermittent coating unit A and a non-continuous coating unit B.

(25) The intermittent coating unit A is constituted by a coating head 10 and a hot-melt supply control device 20 that has a valve mechanism 21 and a valve drive mechanism 22.

(26) The non-continuous coating unit B has a mechanism to vertically vibrate the protrusions 31 that come into contact with the traveling rubber threads, and causes the rubber threads traveling through the coating area of the coating head 10 to vibrate up and down between a coating position and a non-coating position, so that the traveling rubber threads are rapidly moved between a position where they pass through the coating area of the coating head and a position where they are moved away from the coating area, thus performing a non-continuous coating to the rubber threads.

(27) In the shown embodiment, the non-continuous coating unit B is configured such that protrusions 31 project out from the periphery of a cylindrical body, forming a hexagonal prism-shaped rotating body 30 in a horizontal arrangement. Thus, this non-continuous coating unit B corresponds to the stretchable member (rubber thread) vertical drive device 1 in the embodiments of FIG. 1A to FIG. 3B described above.

(28) In this embodiment, the protrusions 31 stick out around the periphery of the cylindrical body, so that the hexagonal prism-shaped rotating body 30 is provided in a horizontal arrangement.

(29) The non-continuous coating unit B is positioned in front of the intermittent coating unit A, and it produces a non-continuous coating operation in the coating section TT of the intermittent coating unit A, and it substantially does not operate in the non-coating section NN.

(30) The non-continuous coating operation of the stretchable member (rubber thread) vertical drive device 1 (non-continuous coating unit B) will now be described.

(31) In FIG. 5, 32 is a guide roller, and 33 is a guide face of the guide roller. 34 is a drive roller. The positions of the rubber threads R are restricted between the guide face 33 of the guide barrel and the drive roller 34.

(32) At the coating timing shown in FIG. 5, the protrusion 31 of the rotating body 30 comes into contact with the rubber threads R and pushes them upward to an upper position.

(33) In this state, the rubber threads R are passing through the coating area Q of the coating head 10. This is a coating state.

(34) At the non-coating timing shown in FIG. 6, the protrusion 31 of the rotating body 30 is separated from the rubber threads R.

(35) In this state, the rubber threads R are located below the coating area Q of the coating head 10. This is a non-coating state.

(36) By selecting the number and spacing of the protrusions 31 of the rotating body 30, the pitch of the pleats can be adjusted to obtain optimum flexibility.

(37) Referring to FIGS. 7 to 11, the coating head 10 is the same as a conventional device in that it is comprised of a head main body 11, a presser plate (blind plate) 12, and a shim plate (distribution plate) 13, an adhesive supply hole 3 and a distribution supply path 4 are formed in the head main body 11, and hot-melt adhesive is supplied to the adhesive application areas Q of slit grooves 5 of the shim plate 13 and in that the rubber threads, etc. R are supplied to and travel through the adhesive application areas Q of the slit grooves 5.

(38) In working the present invention, communicating paths 7 are provided for supplying hot-melt adhesive to the left and right side portions of the adhesive application areas Q.

(39) Each communicating path 7 is a left and right pair with respect to each slit groove 5. Also, the number of the slit grooves 5 (rubber threads R) may be one, two, four, or the like.

(40) In regard to the communicating paths 7 with respect to their adjacent slit grooves 5, the upper end portion 7a on the inlet side may be shared, so that the lower end portions are branched off from the middle and that adhesive is supplied to an enlarged portion 6 of two slit grooves 5 through a single communicating path 7.

(41) The steps for manufacturing a stretchable composite sheet will now be described. FIG. 12 shows the stretchable elastic members (rubber threads) R that are used, and it shows the extended state of stretchable elastic members (rubber threads) when the adhesive HM is applied to the entire peripheral surface of the stretchable elastic members (rubber threads) at specific hot-melt adhesive application positions.

(42) In coating a plurality of stretchable elastic members (rubber threads) with a hot-melt adhesive, the non-continuous coating sections TT are set so as to correspond to a plurality of pleat formation regions T, and the non-coating sections NN are set corresponding to pleat-free regions N.

(43) More specifically, in coating the stretchable elastic members (rubber threads) with the hot-melt adhesive, intermittent coating is performed to form the non-continuous coating sections TT and the non-coating sections NN.

(44) At the adhesive application positions, the stretchable elastic members (rubber threads) to the entire peripheral surface of which the adhesive has adhered are supplied such that these adhesive application positions are at the contact points with the peaks of the pleats (folds).

(45) At an intermediate step of the stretchable composite sheet shown in FIG. 13, at the point when the entire peripheral surface of the stretchable elastic members (rubber threads) R is intermittently being coated with the hot-melt adhesive HM at specific intervals, the plurality of extended stretchable elastic members (rubber threads) R are disposed between two nonwoven fabric sheets F.

(46) Thus, both sides of each of the plurality of stretchable elastic members (rubber threads) R are bonded and fixed to the nonwoven fabrics F at the contact points between the peaks of the two-layer pleats (folds) P and the plurality of stretchable elastic members (rubber threads) that are positioned orthogonally to the peaks of the pleats (folds).

(47) In an intermediate step for the stretchable composite sheet shown in FIGS. 14 and 15, at the adhesive application positions, the stretchable elastic members (rubber threads) to which entire peripheral surface the adhesive has adhered are supplied such that these adhesive application positions are at contact points with the peaks of the pleats (folds).

(48) Both sides of the plurality of stretchable elastic members (rubber threads) are bonded and fixed to the nonwoven fabrics at contact points between the peaks of the two-layer pleats (folds) and the plurality of stretchable elastic members (rubber threads) that are positioned orthogonally to the peaks of the pleats (folds).

(49) In a stretchable composite sheet in which a plurality of stretchable elastic members (rubber threads) are bonded and fixed between two nonwoven fabric sheets to form two-layer pleats <gathers> orthogonal to the plurality of stretchable elastic members (rubber threads), the stretchable composite sheet is completed in which pleats are formed such that both sides of the plurality of stretchable elastic members (rubber threads) are bonded and fixed to the nonwoven fabrics at the contact points between the peaks of the two-layer pleats <gathers> and the plurality of stretchable elastic members (rubber threads) that are positioned orthogonally to the peaks of the pleats <gathers>, and thus the plurality of pleat formation regions are formed, and pleat-free regions are formed where pleats are not formed between a plurality of the pleat formation regions.

(50) The following reference matters are additionally described, although they do not limit the scope of the present invention. It is confirmed that the best pleats are formed in the embodiment under the following conditions: Line speed of rubber threads R: 50 m/min Non-continuous coating pitch: 7 mm

INDUSTRIAL APPLICABILITY

(51) The present invention provides a stretchable composite member that is flexible, has a pleasant feel, and whose pleats are soft to the touch, for the manufacture of disposable diapers. Pleats that are optimal for absorbent products and the like can be formed, and the amount of adhesive that is applied can be reduced, thereby contributing to the development of fields of manufacture of disposable diapers and the like.

DESCRIPTION OF THE REFERENCE NUMERALS

(52) P Pleat (fold) R Stretchable elastic member (rubber thread) 1 Vertical drive device 10 Coating head 30 Rotating cam body