MXPA00010894A - Composite sheet and production method thereof - Google Patents

Abstract

A composite sheet used for a cleaning sheet (1) or the like is formed by joining a base layer (7) with grouped continuous fibers (8a) at a joint line (5). The joint line (5) consists of a first joint line (5A) formed on one side of an axis C-C which bisects the width of the grouped continuous fibers (8a) and a second joint line (5B) formed on the other side. The first and second joint lines (5A, 5B) cross the grouped continuous fibers (8a) obliquely so as to cross each other when extended toward the axis C-C.

Description

MIXED SHEET AND METHOD FOR ELABORATION DIE THE SAME FIELD OF THE INVENTION This invention relates to a bulky mixed sheet consisting of continuous fibers or filaments and, more particularly, to a mixed sheet which is suitably used to remove dust and dirt on floors, walls, windows and the like.

PREVIOUS TECHNIQUE In the accompanying drawings, Figures 8 and 9 are perspective views of the mixed sheets 101 comprising a base sheet, for example, made of non-woven fabric and continuous fibers bonded by heat with the base sheet and Figure 10 is a view. in perspective of a handle 103 of which the mixed sheet is held. These mixed sheets 101 and handle 103 are described in Japanese Patent Application Laid-Open No. 1997-149873. The floors can be cleaned by the mixed sheet 101 with the handle 103 in the hands of the user to collect dust and dirt with the upper surface of the mixed sheet 101. In this already known mixed sheet 101, a plurality of continuous fibers 108 are joined by heat integrally with the base sheet 107 along the lines of union 105. Said mixed sheet 101 is made by placing the continuous fibers 108 on the base sheet 107 and feeding them in a space between a pair of heated rollers for enhancement. As will be evident in Figure 8, the intersections 131 of the tie lines 105 are numerous in the composite sheet 101 and, therefore, the continuous fibers 108 in an inconvenient manner tend to be unevenly distributed in the vicinity of these intersections. during an enhancement procedure. In the case of the mixed sheet 101 as illustrated in Figure 9, the continuous fibers 108 tend to change transverse along an arrow Q toward a side end of the base sheet 107 as the continuous fibers 108 and the sheet base 107 are fed in the direction indicated by an arrow P to the pair of highlighting rollers. Accordingly, it is difficult to regularly distribute the continuous fibers 108 transversely of the base sheet 107. It is an objective of this invention to provide a bulky mixed sheet and a method for making said improved mixed sheet to eliminate the problems encountered in the known mixed sheets.

BRIEF DESCRIPTION OF THE INVENTION According to one aspect of this invention, a mixed sheet having a longitudinal axis is provided, the mixed sheet comprises a base layer having upper and lower surfaces and a surface layer consisting of continuous fibers extending along of the longitudinal axis and having a predetermined width defined between the transversely opposed lateral ends of the surface layer extending along the longitudinal axis and which is joined to at least one of the upper and lower surfaces of the base layer by a plurality of tie lines extending in a direction intersecting the longitudinal axis. In said mixed sheet, the tie lines comprise a plurality of first tie lines extending in intervals in a half of the surface layer defined on one side of the longitudinal axis extending as to bisect the width of the surface layer and a plurality of second tie lines that also extend at intervals in the other half of the surface layer on the other side of the longitudinal axis. The first and second connecting lines extend obliquely to the longitudinal axis to cross each other in the extensions of the first and second connecting lines towards the longitudinal axis. According to another aspect of this invention, there is provided a method for making a mixed sheet having a longitudinal axis, the mixed sheet comprising the steps of continuously feeding a base layer tape having upper and lower surfaces and a tape. surface layer consisting of continuous fibers extending along the longitudinal axis and having a predetermined width defined between transversely opposed lateral ends of the surface layer extending along the longitudinal axis, placing the surface layer tape on at least one surface of the base layer tape and attaching the surface layer tape to the base layer tape along a plurality of tie lines extending in a direction that intersects the longitudinal axis. In said method, this invention further comprises the steps for derailing and expanding a bundle of continuous filaments for the surface layer tape to the predetermined width on the surface of the base layer tape and providing a plurality of first tie lines that are they extend at intervals in one half of the surface layer ribbon defined on one side of the longitudinal axis that bisects the width of the surface layer ribbon and a plurality of second joint lines that also extend at intervals over the other half of the surface layer tape defined on the other side of the longitudinal axis so as to achieve that the first and second joint lines extend obliquely to the longitudinal axis and intersect with each other on extensions of the first and second connecting lines towards the longitudinal axis, whereby the first and second connecting lines are formed successively from the longitudinal axis towards the ends laterally opposed sides of the surface layer tape as the base layer tape and the surface layer tape are fed into the longitudinal axis.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing one embodiment of a sheet for cleaning; Figure 2 is a sectional view along line II-II of Figure 1; Figure 3 is a plan view corresponding to Figure 1; Figure 4 is a view similar to Figure 3 showing an embodiment of this invention; Figure 5 is a view similar to Figure 3 showing another embodiment of this invention; Figure 6 is a view similar to Figure 3 showing still another embodiment of this invention; Figure 7 is a fragmented larger scale figure corresponding to Figure 3; Figure 8 is a plan view showing a cleaning sheet of the prior art; Figure 9 is a view similar to Figure 8 of the prior art; and Figure 10 is a perspective view of a handle equipped with a mixed sheet.

DESCRIPTION OF THE BEST WAY TO WORK FROM THE INVENTION The details regarding the composite sheet and the method for making same in accordance with this invention will be better understood from the description given herein with reference to the accompanying drawings. Although this invention is not intended to be limited to a sheet for cleaning, one embodiment of this invention will be described primarily in terms of sheet to clean. Figures 1 and 2 are a perspective view showing a sheet for cleaning 1 as an embodiment of the composite sheet of the invention and a view along the line ll-ll of figure 1. The sheet for cleaning 1 comprises a base layer 7 consisting of a thermoplastic nonwoven fabric and a surface layer 8 consisting of a plurality of thermoplastic continuous fibers (filaments) 8a which are joined to the upper surface of the base layer 7 along a plurality of connecting lines 5. The cleaning sheet 1 can be used with the base layer 7 fixed along its lateral edges 9 transversely opposed to a handle of figure 10 to remove dust and dirt on a floor by means of the surface layer 8, and also with the cleaning sheet 1 held in the user's hand. The continuous fibers 8a of the surface layer 8 extend parallel to one another between the lateral ends 9 longitudinally of the base layer 7 (ie, between the left and right sides as indicated by an arrow A). The fibers 8a are successively bonded onto the bond lines 5 by heat and pressure and, as a result, the fibers 8a on the binding lines 5 are no longer fibrous and lines with compressed grooves and raised regions are defined which describe arcs 8b that are alternate Preferably, the height of each of the elevations describing an arch is dimensioned to more than three times a total thickness of a portion of the junction line (the bottom of the compressed groove) and the base layer (see Figure 2) . Said surface layer 8 of the continuous fibers has excellent bulging, elasticity and compressibility characteristics as well as three dimensional appearances, and needless to say, these characteristics are superior to those of the base layer 7. In actual use the cleaning sheet 1 the surface layer 8 is placed against the floor and moves in the direction indicated by the arrow A or in a direction intersecting it at a right angle as indicated by an arrow B. This movement of the sheet to clean 1 ensures that the portions describing an arc of the fibers 8a collect and contain dust and dirt in themselves. The surface layer 8 is also attached to the longitudinal edges of the base layer 7 along the joint lines 15, although the joint lines 15 are not necessarily required for the cleaning sheet 1. Figure 3 is a plan view of the cleaning sheet 1. The widths of the surface layer 8 are enlarged schematically in this figure. The surface layer 8 has its width completely bisected by the longitudinal axis C-C. The base layer 7 has a plurality of first tie lines 5A in an upper half with respect to the longitudinal axis C-C as seen in Figure 3 and a plurality of second tie lines 5B in a lower half. The first connecting lines 5A extend parallel to each other at substantially regular intervals and the second connecting lines 5B also extend in a similar manner. The first and second connecting lines 5A5B extend obliquely to the fibers 8a so that the first and second connecting lines 5A and 5B intersect each other if they extend further towards the longitudinal axis C-C. It should be understood that the first and second connecting lines 5A, 5B can actually intersect with each other on the longitudinal axis CC as indicated in Figure 3. The first and second connecting lines 5A, 5B extend at the same angle with with respect to the longitudinal axis CC, that is, to the fibers 8a. The first and second tie lines 5A, 5B have their first ends 11 A, 11 B resting about the longitudinal axis C-C and their second ends 12 A, 12 B rest around the lateral extremities 9, respectively. With reference to the drawing of Figure 3, a plurality of imaginary chain lines H extend transversely to the cleaning sheet 1 to intersect the longitudinal axis C-C at right angles. Each imaginary line H intersecting the first ends of the corresponding pair of junction lines 5A, 5B intersects the second ends 12A, 12B of the adjacent pair of junction lines 5A, 5B. In Figure 3, the imaginary line H-i intersecting the first end 11 of each first joint line 5A intersects the second end 12A of the first joint line 5A before or after the adjacent one. All the continuous fibers 8a extending parallel to each other in the direction A are joined to the base layer 7 on the first or second joining lines 5A, 5B and the fibers 8a do not detach from the base layer 7.

Although a size of the base layer 7 of the cleaning sheet 1 is not specified, preferably the base layer 7 has a length of 5 ~ 200 cm and a width of 5 ~ 50 cm. The base layer 7 may be formed of dimensionally stable materials such as a nonwoven or woven fabric made of thermoplastic synthetic fibers and a thermoplastic synthetic resin film and other materials. Preferred examples of the non-woven fabric include a spunbonded nonwoven fabric and a knitted non-woven fabric both made of polyethylene / polyester blended fibers. Preferably, the nonwoven fabric or film has a unit weight of 5 ~ 200 g / m2. Examples of the continuous fibers 8a are continuous filaments made of polyethylene, polypropylene, nylon, polyester, rayon and others. A preferable example of the continuous fibers 8a may be obtained by uncoupling or opening a bundle of these continuous fibers in a filament bundle form and then expanding the open fibers to a predetermined width by conventional methods. The bundle of filaments is a package of continuous polymer filaments in the form of a commercially available rope. The continuous fibers 8a can be a denier per filament of 2-20. Preferably, the fibers 8a are folded because this offers bulging and compressibility thus facilitating good collection of dust and dirt from the floor. Preferably, the number of folds is within a range of 5-25 crests per 2.54 cm. It is recommended that the fibers 8a have a unit weight of 20-500 g / m2. It is possible to treat the fibers 8a with oil or with a hydrophilic surfactant in order to improve the efficiency in the collection of dust or the capacities to absorb water. Preferably, the bond lines 5 can extend at an angle of 10-80 degrees, more preferably 15-75 degrees with respect to the longitudinal axis C-C. Although not specified, each bond line 5 preferably has a width of 0.5 - 10 mm. Although Figure 3 illustrates the fibers 8a as being attached only to the upper surface of the base layer 7, it is also possible to join the fibers 8a to the lower surface of the base layer 7. When the fibers 8a are so bonded to the surface upper as the lower of the base layer 7, the lines of union 5 on the upper surface coincide with the lines of union 5 on the lower surface in their patterns as well as in their placements. Figures 4 through 6 are views similar to Figure 3 showing other embodiments of this invention. In the cleaning sheet 1 shown in FIG. 3, the imaginary line H intersecting the first end 11A of each first joining line 5A intersects the second end 12A of the first bonding line 5A immediately adjacent. In the cleaning sheet 1 shown in FIG. 5, all the connecting lines 5 are relatively short. The first connecting lines 5A distributed in the upper half with respect to the longitudinal axis C-C comprise the first connecting lines 5C having their first ends 11 A on the longitudinal axis C-C and the first connecting lines 5D having their second ends 12A on one of the lateral ends 9 of the base layer 7. Similarly, the second connecting lines 5B distributed in the lower half with respect to the longitudinal axis C-C comprise the second connecting lines 5E having their first ends 11 B on the longitudinal axis C-C and the second connecting lines 5F having their second ends 12B on the other lateral end 9 of the base layer 7. It should be understood that, in the case of the first and second tie lines 5A, 5B shown in Figure 5, the ends of the respective tie lines resting on or adjacent the longitudinal axis CC are referred to as the first ends 11 A, 12 A while the ends thereof resting on or adjacent to the lateral ends 9 are referred to as the second ends 11B, 12B. The imaginary line H intersecting the first end 11A of each first line of junction 5C or 5D intersects the second end 12A of the first immediately adjacent junction line 5C or 5D. The same relationship is maintained between the second joining line 5B and the imaginary line H. The fibers 8a are joined to the base layer 7 along any of the first joining lines 5A comprising the 5C and 5D or the second ones joining lines 5B comprising 5E and 5F. In this way, the fibers 8A do not detach from the base layer 7. In the case of the cleaning sheet shown in Figure 6, the connecting lines 5 extend from the longitudinal axis CC to the ends lateral 9 although the first ends 11 A, 11 B of the first and second connecting lines 5A, 5B are outside the intersection on the longitudinal axis C-C. However, the extensions of these first and second connecting lines 5A , 5B towards the longitudinal axis CC intersect with each other. The imaginary line H intersecting the first end 11A of each first junction line 5A intersects the second end 12A of the first junction line 5A immediately adjacent. The same relationship between the second joining line 5B and the imaginary line H is maintained. The cleaning sheet 1 as described above with reference to figures 3 to 6 can be made by placing a tape for the surface layer 8 of the continuous fibers 8a which expand to a predetermined width on a belt for the base layer 7 and continuously feeding these belts in a defined space between a pair of heated rollers for an enhancement treatment. At least one of the pair of rollers has projections having a pattern corresponding to the joining lines 5 and the pair of rollers are rotated so that the connecting lines 5 can be formed successively on the belt of the surface layer 8 from the longitudinal axis C-C to the opposite side 8c transversely thereof. In this way, the fibers 8 can be distributed over the belt of the base layer 7 with a substantially uniform thickness as the connecting lines 5 are successively formed. This is true even when the belt of the surface layer 8 is fed to the rollers under a condition that the belt of the surface layer 8 is relatively dense in an intermediate region transversely thereof. Figure 7 is a fragmentary larger scale figure corresponding to Figure 3, illustrating a way in which the lines of junction 5 intersect the imaginary lines H. An effective length L of the joint line 5 throughout of the imaginary line H corresponds to a total length of portions in which the junction line 5 intersects the imaginary line H. For example, a junction length Li in connection with the imaginary line Hi can be expressed as Li = a + b + c + d Similarly, a link length L2 in connection with the imaginary line H2 can be expressed as L2 = a + d + e. The effective length L depends on the patterns of the bond lines 5. It is preferable in this invention to have the bond lines 5 to provide an effective length L of which a ratio of a maximum to a minimum is less than 2. For example , the pattern of the connecting lines 5 is selected so that the imaginary lines H intersecting the first ends 11A, 11B of the connecting lines 5 can also separate the second ends 12A, 12B as in the modalities shown in FIGS. Figures 3 to 6. Said patterns of the connecting lines 5 allow the belt of the surface layer 8 and the belt of the base layer 7 to continuously contact the projections of the rollers for the enhancement. Since the rolls do not press these tapes intermittently but continuously, the continuous fibers 8a of the tape of the surface layer 8 can easily expand with a uniform thickness over the base layer tape 7. In an embossing machine it can also be decrease the chances of damage caused by pressing intermittently. In the following steps of the sheet that was obtained in the above procedure the tape of the surface layer 8 is attached to the tape of the base layer 7 along said joining line 15 as shown in Figure 3, and these ribbons are cut into a mixed sheet as shown in Figures 3 to 6. The mixed sheet can be used not only for the cleaning sheet 1 but also for a cushioned material if the surface layer 8 of the continuous fibers 8a is bulky and a material that absorbs disposable or non-disposable water if the continuous fibers 8a are water absorbers or hydrophilic. The mixed sheet according to this invention has the surface layer of the continuous fibers bonded to the base layer with a substantially uniform thickness. Being free of irregularities in the distribution of the fibers, this mixed sheet can be used as a good cleaning sheet to uniformly clean a floor or the like. The composite sheet of this invention is useful for a wide variety of applications including household cleaners for general purposes and many other end uses.

Claims (18)

NOVELTY OF THE INVENTION CLAIMS

1. - A mixed sheet having a longitudinal axis, said mixed sheet comprising a base layer having upper and lower surfaces and a surface layer consisting of continuous fibers extending along said longitudinal axis and having a predetermined width defined between the transversely opposed lateral ends of the surface layer along the longitudinal axis and joined to at least one of the upper and lower surfaces by a plurality of joining lines extending in a direction intersecting the longitudinal axis, in which: said tie lines comprise a plurality of first tie lines extending in intervals in a half of the surface layer defined on one of the sides of the longitudinal axis to bisect the width of the surface layer and a plurality of second joint lines that also extend at intervals in the other half of the surface layer on the other side of the long axis where said first and second connecting lines extend obliquely to the longitudinal axis to intersect with each other in the extensions of the first and the second connecting lines towards the longitudinal axis.

2. The mixed sheet according to claim 1, further characterized in that said first and second joining lines are parallel with each other at almost regular intervals in one half and half, respectively.

3. The mixed sheet according to claim 1, further characterized in that said continuous fibers of the surface layer are obtained by unraveling a bundle of continuous fiber filament and expanding the unraveled filament bundle into a substantially uniform ribbon having a predetermined width

4. The mixed sheet according to claim 1, further characterized in that each of the lines of union define a compressed slot.

5. The mixed sheet according to claim 1, further characterized in that said surface layer has elevation regions that describe an arc defined between each pair of said lines of union which are adjacent to each other, each of the regions of elevation that describe an arch have characteristics of bulge, elasticity and compressibility superior to those of the base layer, the height of each of the elevation regions that describe an arch its dimension is determined at least three times a total thickness of a portion of said junction line and said base layer.

6. The mixed sheet according to claim 1, further characterized in that said base layer has a length of 5-200 cm along the longitudinal axis and a width of 5-50 cm in a direction intersecting the longitudinal axis .

7. - The mixed sheet according to claim 1, further characterized in that said base layer has a unit weight of 5-200 g / m2 and said surface layer has a unit weight of 20-500 g / m2.

8. The mixed sheet according to claim 1, further characterized in that said continuous fibers of the surface layer has a fiber denier of 2-20.

9. The mixed sheet according to claim 1, further characterized in that said first and second connecting lines intersect practically with each other on the longitudinal axis.

10. The mixed sheet according to claim 1, further characterized in that said first and second joining lines extend from the longitudinal axis to the transversely opposed lateral ends of the surface layer.

11. The mixed sheet according to claim 1, further characterized by a ratio of a maximum against a minimum of a total length of crosses between an imaginary line supposedly extended at a right angle to the longitudinal axis along the layer of surface and said first and second joining lines is less than 2.

12. The mixed sheet according to claim 1, further characterized in that the base layer and the surface layer contain thermoplastics so that the bond lines are formed by melting said thermoplastics.

13. The mixed sheet according to claim 1, further characterized in that said junction lines are lines joined by heat and pressure.

14. A method for making a mixed sheet having a longitudinal axis, said mixed sheet comprising the steps of continuously feeding a base layer tape having upper and lower surfaces and a surface layer tape consisting of continuous fibers that they extend along the longitudinal axis and having a predetermined width defined between the transversely opposed lateral ends of the surface layer extending along the longitudinal axis, placing said surface layer tape on at least one surface of the base layer tape and attaching the surface layer tape to the base layer tape along a plurality of joining lines extending in a direction intersecting the longitudinal axis, further said method comprises the following steps: unraveling and expanding a continuous filament tow fiber for the surface layer tape to a predetermined width of one of the surfaces of the base layer tape; and providing a plurality of first tie lines extending at intervals in one half of the surface layer tape defined on one of the sides of the longitudinal axis to bisect the width of the surface layer and a plurality of second tie lines which also extend at intervals in the other half of the surface layer tape on the other side of the longitudinal axis to achieve that the first and second joint lines extend obliquely to the longitudinal axis and intersect with each other in extensions of the first and second connecting lines towards the longitudinal axis, wherein said first and second connecting lines are formed successively from the longitudinal axis towards the transversely opposed lateral ends of the surface layer tape according to said base layer tape and said Surface layer tape are fed in the direction of the longitudinal axis.

15. The method according to claim 14, further characterized in that said first and second junction lines are parallel to each other at practically regular intervals in a half region and another half region, respectively.

16. The method according to claim 14, further characterized in that said first connecting lines and second connecting lines respectively have first ends that rest around the longitudinal axis and second ends that rest around the lateral ends of the layer tape of surface and a line extending transversely along the continuous fibers of said surface layer tape which intersects the first ends of either the first or the second joining line and also intersects the second end of a connecting line different from any of the first and second connecting lines.

17. The method according to claim 14, further characterized in that said first lines of union and second lines of union are formed because a ratio of a maximum against a minimum of a total length of crosses between an imaginary line supposedly extended at a right angle to the longitudinal axis and the first and second joining lines is less than 2.

18. The method according to claim 14, further characterized in that said base layer tape and said surface layer tape contain thermoplastics. because the first and second lines of union are formed by melting said thermoplastics.