US3677484A

US3677484A - Method for winding up a thin layer material having a broad width

Info

Publication number: US3677484A
Application number: US79091A
Authority: US
Inventors: Masahide Yazawa; Haruhisa Tani
Original assignee: Polymer Processing Research Institute Ltd
Current assignee: Polymer Processing Research Institute Ltd
Priority date: 1969-12-09
Filing date: 1970-10-08
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18
Also published as: FR2073158A5; DE2052202B1; GB1315687A; NL7109269A; NL146457B

Abstract

A thin layer material having a large width can be wound up around a winding core by continuously supplying and inserting an elongated continuous yarn-like material, which traverses the thin layer material, in between one wound layer and another to leave a clearance along the inserted yarn-like material. Irregularities in thickness of the thin layer material are absorbed into the clearance, whereby a long length of wide thin layer material can be wound up into a cylindrical form of larger diameter. Further, by making a width to which the yarn-like material is extended, when supplied by reciprocatingly traversing the layer material, larger than the width of the wound thin layer material, and thus supplying the yarn-like material beyond both the edge parts of the thin layer material, the greater portion of thus supplied yarn-like material can be formed into almost wound at first and then arc chords at both the side faces of the wound cylindrical roll of the thin layer material, and the resulting chords cover the side surfaces of the woundup cylindrical roll of the layer material, whereby the side faces of the wound roll are protected through a large number of the yarn-like materials forming said arc chords, and at the same time, deformation, such as telescoping of the wound thin layer material can be prevented, even when loosely wound up and also the successive unwinding can be easily assured.

Description

United States Patent Yazawa et a].

[ 1 July 18, 1972 Polymer Processing Research Institute Ltd., Tokyo, Japan 221 Filed: octs, 1910 2: Appl.No.: 79,091

[73] Assignee:

[30] Foreign Application Priority Data Dec. 9, 1969 Japan ..44/99208 [52] U.S. Cl. ..242/54 R, 28/21 [51 Int. Cl ..B65h 75/00 [58] Field 0! Search ..242/54 R; 28/2] [56] Relerenoes Cited UNITED STATES PATENTS 2,386,823 l0/l945 Thornburgh ..242/54 R X 3,289,440 l2/l966 Buddecke ..242/54 R X 3,32 I ,185 5/l967 Zenke .242/54 R X 3,583,65l 6/1971 Schulze et al. ..242/54 R Primary ExaminerStanley N. Gilreath Assistant Examiner-Milton Gerstein Attorney-Fred C. Philpitt [57] ABSTRACT A thin layer material having a large width can be wound up around a winding core by continuously supplying and inserting an elongated continuous yarn-like material, which traverses the thin layer material, in between one wound layer and another to leave a clearance along the inserted yarn-like material. lrregularities in thickness of the thin layer material are absorbed into the clearance, whereby a long length of wide thin layer material can be wound up into a cylindrical form of larger diameter. Further, by making a width to which the yarnlike material is extended, when supplied by reciprocatingly traversing the layer material, larger than the width of the wound thin layer material, and thus supplying the yam-like material beyond both the edge parts of the thin layer material, the greater portion of thus supplied yarn-like material can be formed into almost wound at first and then are chords at both the side faces of the wound cylindrical roll of the thin layer material, and the resulting chords cover the side surfaces of the woundup cylindrical roll of the layer material, whereby the side faces of the wound roll are protected through a large number of the yam-like materials forming said are chords, and at the same time, deformation, such as telescoping of the wound thin layer material can be prevented, even when loosely wound up and also the successive unwinding can be easily assured.

1 Claim, 4 Drawing Figures Patented July 18, 1972 2 Sheets-Sheet l Patented July 18, 1972 2 Sheets-Sheet 'l FIG.2

METHOD FOR WINDING UP A THIN LAYER MATERIAL HAVING A BROAD WIDTH This invention relates to a method for winding up a thin layer material having a broad width, and more particularly to a method for winding up a thin layer material having a broad width, where a thin layer material having a broad width such as a film and thinly spread filament tow, etc., is wound up onto a winding core, which comprises continuously supplying and inserting an elongated consecutive yarn-like material, reciprocatingly traversing the thin layer material into between one wound layer and another, even if there is a little irregularity in thickness of the thin layer material; winding up the thin layer material while leaving a clearance along the yarn-like material between the wound up layers thereof, thereby to make the clearance absorb the irregularity in the thickness and make it possible to wind up the thin layer material into a roll of cylindrical form, even if the long thin layer material is to be wound up into a roll of larger diameter; making a width to which the yarn-like material is extended, larger than the width of the wound thin layer material namely beyond the side edge of thin layer material when supplied by reciprocatingly traversing the layer; and allowing the supplied portion of the yarn-like material over the width of the wound thin layer material to cover both the side faces of wound cylinder in a form of wound arc chords to protect the side faces of woundup thin layer material roll by piled up layers of a large number of arc chords of the yarn-like material as well as protect deformation, such as telescoping, of the wound-up thin layer material, even if the thin layer material is wound up under a low tension and make sure unwinding.

The "thin layer material having a broad width" defined in the present invention can include the following materials.

Group A: Yarn and filament layers of organic and inorganic fibers extended to a thin layer, which can be illustrated by:

I. Thin, parallel fiber layer of a large number of parallel fibers prepared in a process for producing a filament tow of artificial fibers in a laterally extended state, for example, 30 50 cm wide in case where a thickness is 300,000 500,000 denier (d.) in the total denier (d.), and the parallel fiber layer laterally re-extended to an approximately equal thickness afier bundling said thin, parallel fiber layers in tow form, and further subjected to a towform processing such as heat-treatment, drying, bleaching, drying, crimping, etc.

2. Parallel yarn layer of filament yarns which has been subjected to stretching, heat treating, cohering by pasting, drying and laterally extended in a parallel state where, for example, 200 to 300 filament yarns are extended laterally to a width of 50 cm.

3. Warped parallel yarn layer of filament yarns and spun yarns and parallel yarn layer of dyed and processed yarns thereof.

4. Parallel monoaxilly stretched tape layer, having been stretched in fiat and parallel arrangement, and parallel split yarn layer thereof having been subjected to a splitting process.

5. Split fiber web in a reticular structure obtained by subjecting a broad monoaxially stretched film to a splitting process; a non-woven fabric of split fibers which is obtained by further extending said split fibers web to a definite broadness and whose web fiber arrangement is fixed by an adhesive binder; and non-woven fabric of split fibers having warp and weft construction and prepared from said split fiber web where the warp and wefi layers are fixed together.

Group B: Film and sheet such as:

6. Non-stretched film of thermoplastic polymer whose irregularity in thickness is generally in a range of t 5 30 percent when molded by extrusion.

7. Broad, monoaxially stretched film.

8. Biaxially stretched film.

9. Processed films and laminates of the films (6), (7) and The "Yarn-like material" used in the present invention means a narrow and elongated consecutive yarn-form product having a good dimensional stability in a longitudinal direction and a little elastic bulkiness in the direction of thickness, and includes, for example:

i. Spun yarn, filament yarn and split-fiber yarn having a suitable thickness; a thread, cord and string prepared by doubling and twisting these yarns.

ii. Yarn prepared by doubling and twisting straight yarn together with other yarn in a bulky manner to endow an elastic bulkiness to the thickness direction of the yarn, the yarn twisted together with crimped yarn and flufi'ed yarn.

iii. Tape, string and bristle, of ordinary or foamed structure,

etc.

The thin layer material, as explained above, has always some extent of deviations 5 30 percent) in thikness along both lateral and longitudinal directions in its manufacturing and processing processes, but an occurence of such irregularities in thickness is an inevitable phenomenon. When such a thin layer material is wound up plainly, as it is, under a tension, an irregularity in diameter of the wound roll, that is, convexed parts and concaved parts appears along the entire width due to the irregularity of the material in thickness when a considerably long thin layer material is wound up. Tension at every convex part becomes higher, and such a higher tension gives an unfavorable influence upon the quality of wound-up product. Therefore, the plain winding of such a thin layer material, whose length exceeds several 1000 meters, has been heretofore regarded as being impossible, and such a roll product has not been available commercially. Of course, it is possible to make the irregularity in thickness of the thin layer material be absorbed in a clearance between the wound layers if the winding tension is made lower and a loose winding-up is carried out. Then no irreguarity appears on the surface of the wound roll, but in that case the wound-up cylindrical roll has such disadvantages that the wound-up layers are liable to slip in a longitudinal direction of the winding core, that is telescoping, and a winding deformation and roll collapse take place remarkably. Therefore, the winding-up of long thin layer material has not been practically effected yet.

Accordingly, it is an object of the present invention to provide a method for winding up a sufficiently long, thin layer material to form a wound cylindrical roll of large diameter without the above-mentioned disadvantages in effecting plain winding-up of such a thin layer material having a broad width and irregularities in thickness in which the yarn-like material inserted into between one layer and another, protects the side faces of the wound layers, prevents the roll from getting out of its initially wound up form and makes sure unwinding operation.

Now, the present method will be explained in detail, referring to the accompanying drawings:

FIG. la shows a state where a yarn-like material is supplied onto a thin layer material while being reciprocatingly overtraversed to a width greater than the width of the thin layer material, which has a broad width;

FIG. lb shows how the over-traversed yarn-like material is wound over a winding core with an increase in the winding diameter of the thin layer material roll',

FIG. 2 shows a state where the yarn-like material, which becomes a chord over the side face of the wound cylinder when the thin layer material is wound onto the winding core, is piled up in layers, if the winding diameter is smaller;

FIG. 3 shows a schematic plan view of a winding apparatus as an example.

FIG. 1a is a plan view of the wound-up thin layer material, which has been unfolded into a plane. With the progress of a thin layer material 1 of a width W, a yarn-like material 2 crosses the thin layer material at an angle 0 to the travelling direction of thin layer material and is placed on the thin layer material to the extent of length L. The yarn-like material leaves the thin layer material at a point 3 at the left edge of the thin layer material and is over-traversed up to a point 4 in the forward course. Then, in the backward course, the yarn-like material is placed again on the thin layer material at a point at the left edge of the thin layer material, At that time, the yarn-like material constituting two sides of a triangle as shown by the dotted line from the points 3, through 4 to 5 goes along the side surface of the wound material as a chord from point 3 to point 5 as indicated in a full line in the drawing, owing to a tension applied to the yarn-like material. ln the case where its length l is larger than the circumference of the winding core, the yarn-like material, at the initial stage of winding, comes in touch with the winding core 6 after it leaves the edge of the thin layer material and advances along the side surface thereof, as shown by I, in FIG. lb and is wound around the winding core. When the winding diameter increases from d, to d,, I, further becomes 1, in the U form from the y form on the winding core. With further increase in the winding diameter, the contact length of 1,, (lindicates arbitral chord of I) with the winding core gradually becomes short, and finally 1,, leaves the winding core after it has taken a tangential line form, and then takes a chord form. That is to say, with the increase in the winding diameter, a degree of opening of the V-shaped angle formed by the yarn-like material increases, and I, becomes a tangential line to the winding core at the winding diameter d,. Thereafter, 1,, becomes an arc chord to the winding circumference without any contact with the winding core. With further increase in the winding diameter, the chord 1,, appears more than once at the side face of the wound roll. That is, the chord 1,, appears twice as 1 on one side face of the wound cylinder at some winding diameter, as shown in the drawing. At that time, 1, appears twice at the other side face thereof. In other words, L is placed more than four times on the thin layer material by one round. With further increase in the winding diameter, the numbers of I,, and L by one round are increased, though not shown in the drawings. In the wound up state, 1,, at the side face of the wound cylinder lies far from the edge part of the wound cylinder and approaches the edge part with greater inclination. With the increase of winding diameter the inclination of 1,, becomes smaller. From the point where 1,, takes a tangential line form to the winding core, 1,, runs almost straight along the side face of the wound cylinder. Accordingly, as shown in FIG. 2, the wound form is such that nearer the wound chord 1,, to the winding core 6, the thicker the piling of 1,,.

FIG. 3 shows one embodiment of an apparatus for winding up a thin layer material. A yarn-like material 2 is supplied from a bobbin 7, and passes through resistance rods 8 and 8' to give a proper tension thereto, through a guide 9 provided with a coil spring to keep a tension almost constant, even if a pulling out speed of the yarn-like material is changed, for instance, at the time of over-traversing, and through a tip guide 12 at a traverse rod ll, whose root end is supported by a pivot l0, and reci rocatingly traversed over a cylindrical roll of the thin layer l3, which has been already wound up. The yarn-like material is over-traversed beyond the width of the wound thin layer material and reciprocatingly moves between points 4 and 4'. The yarn-like material is continuously pulled out as the wound roll revolves and inserted into between one layer and another of the thin layer material at an inclined angle. The shape, which the over-traversed yarn-like material takes at both the side faces of the cylindrical wound-up layer, has been already explained above, referring to FIG. lb. The change in the supply speed of the yarn-like material according to the change in the form of I, from the points 3, through 4 to 5 is adjusted by elongation or contracting of the coil spring and the yarn-like material is supplied under an almost uniform tension. Any other suitable method for traversing the yarn-like material can also be employed.

The first object and effect of inserting the yarn-like material in between one layer and another of the wound cylindrical roll is to provide an inclined clearance between the layers by insertion of the yarn-like material which allows an irregularity in the thickness of the thin layer material to be absorbed in the clearance and thus makes it possible to wind up a considerably lengths of thin layer material into a cylindrical roll, because the yarn-like material, even if inserted at a constant pitch, is inserted many times into each neighboring layers and scattered in an inclined form between each layer of the wound roll at some winding diameter, since the winding diameter of the thin layer material increases on each round and the inserting position of the yarn-like material is consequently changed.

The second object and effect is, as explained, referring to the drawing, to provide an action which protects an edge part of the wound layers of the thin layer material by the use of wound chord layers at the side faces of the cylindrical wound roll.

The third object and effect is to completely prevent a winding collapse, because the side face of the wound cylinder are protected from slipping by the wound chord in accordance with the present invention. In the case where there are many irregularities in the thickness of the thin layer material, it is a usual practice to loosen the winding tension so as to absorb the irregularities and effect plain winding up of the thin layer material without inserting the yarn-like material as in the present invention. However, in case where a long, thin layer material is wound up into a roll of larger diameter, the wound layers are liable to slip out and sometimes are transformed into a shape like a telescope. That is, winding deformation and roll collapse often occur in the usual winding practice.

The fourth object and effect is to make sure that the unwinding operation is without any damage to remaining or newly developed fluff, which is particularly important in the case where the thin layer material is a broad, parallel filament or yarn layer, because, when the yarn-like material is inserted into between the layers at a constant pitch, the fluffs, which are liable to remain or appear in the yarn layer when unwinding the wound layers, are swept away and separated by yarnlike material unwound together with the thin layer material by a separate means. For example, when an inclined and elongated continuous yarn-like material is inserted into between the layers one by one round at the start to wind up the layer onto the winding core, the number of inserted yarn-like material in each round is increased with an increase in the winding diameter from the start of winding. That is to say, the wound layer is subjected to sweeping by a number of the yarnlike material in one round, at the unwinding, in the case of the wound layers of large diameter. Even if the unwinding comes near the winding core, the fluffs are swept away once in one turn.

Even if a rate of irregularity in the thickness of the thin layer material is equal throughout one winding process, an absolute value of dimension in the irregularity in the thickness becomes larger with an increase in the thickness of the thin layer material. Therefore, in the present invention, to absorb such irregularity in the thickness, at yarn-like material having a larger thickness must be used to make the clearance larger or winding-up must be effected under a low tension in a range not to allow the inserted yarn-like material to slip or move. In that case, use of a yarn-like material having an elastic bulkiness in the thickness direction is more preferable and meets the object of preventing the wound layers and the yarn-like material from slipping, and also prevents a winding from deforming and a package from collapsing, whereby a long, thin layer material can be wound up into a cylindrical roll of larger diameter.

As explained above, the thin layer material having a broad width includes the Group (A) of fibers and yarns and the Group (B) of films and sheets, and the present invention is applicable to any of these groups effectively, but there is some modification in application, depending upon the groups.

Now, further explanation will be made according to these groups:

First of all, explanation is made in case of tow of the Group (A) l Nowadays the commercially available tow is supplied in a package of 50 kg of crimped tows all prepared by a stuffer box method. When the tow is made into short fiber sliver according to a tow spinning method, for example, by

heating, stretching and cutting, the crimps are so stretched out that they have no recovering ability. Therefore, the significance to endow crimps is merely to improve a clinging property of the fibers to each other and has the object to make the handling thereof free from any trouble in case of unpacking, etc. in subsequent processes. However, the crimped tow is bulky and therefore its shipping form is a package of fibers, whose apparent winding density is as low as 0.26 0.30. As a result, its packaging cost and transportation cost become higher. Though the parallel fibers may be directly wound up onto a bobbin, flufls are liable to be generated at the unwinding, and once fiuffs are generated, these fluffs induce another fiuffs. Consequently, smooth unwinding is impossible. When wound up by traversing, the tow undergoes false twisting of a long pitch between each turning back and the parallel properties of the fibers are sometimes damaged. Thus, the tow has not yet been practically wound up.

Filament tows of polyester, nylon, polypropylene, polyacrylic, etc. have been heretofore produced and procescd as a broad, thin layer material of 30 50 cm of a tow of 300,000 to 500,000 d. not only up to a stretching step, but also to a heat-treating step except for the polyacrylic fibers, and if they can be plainly wound up and unwound without any trouble, the shipping forms will become smaller and the transportation cost will become cheaper. Thus, an invention of a better method for enabling the plain winding-up and easy unwinding has been longed for.

For tows subjected to dyeing processing in a bundled state and then laterally extended or for tows whose crimps are fixed under a saturated vapor pressure, temporarily stretched and set in order to leave remaining crimps suitable for the spinnability under the atmospheric pressure steam at l C to avoid the trouble in the subsequent spinning caused by excessive crimps and then laterally extended to a width of 30 50 cm, while keeping the parallel arrangement of the fibers as they are, an appearance of a better winding process has been also longed for.

If a tow of 300,000 to 500,000 d. can be plainly wound up in a paralleland laterally extended state of the fibers to a width of about 50 cm, without any trouble to the unwinding in a noncrimped state, it is possible to wind up and package the fiber layer at an apparent winding density of 0.5 0.8, that is, in a volume A to /5 smaller than the packaged volume of the crimped tow by conventional practice. However, in practice, it has been impossible to effect a sure unwinding because of remaining fluffs, and as already explained above, such winding-up has not been practically employed yet. When a narrow bundle of tows is wound up to a broad width by traversing, false twisting is applied to the tows as aforementioned, and a disturbance appears in arrangement or in the parallel properties of the fibers. Or, a damage due to fluff appears in case of unwinding. As these disadvantages are brought about, a package of about 100 kg of crimped tow in a carton box is employed in the current practice.

However, by employing the method of the present invention, the fluffs are swept away by the inserted yarn-like material at the unwinding, and therefore the unwinding can be effected without any trouble. That is, a cylindrical plain winding-up can be effected. For example, a tow laterally extended to a width of 50 cm is plainly wound up onto a winding core having a diameter of cm, and the wound cylindrical roll having an apparent winding density of 0.4] can be obtained when the winding diameter reaches 80 cm. That is, fibers of I00 kg can be plainly wound up. In view of the fact that it is easy to effect windingup having an apparent winding density of 0.5 0.8 in the ordinary winding-up oi the fibers and yarns, it is possible to provide a sufficient clearance for inserting the yarn-like material, when plain winding having such a low apparent winding density as explained above, is eflected, and the possibility for sufficiently absorbing the irregularities in the thickness by inserting a highly bulky, thick yarn-like material under a low tension can be given thereby. However, even in this case, there is a fear of collapse of edge part towards the side faces of the wound layers in case of the parallel fiber layer. Such a fear can be overcome if winding is carried out by a device which enables to gradually narrow the width of the wound layers according to the increase in the thickness of the wound layers. For expanding or narrowing the width of the parallel fibers, another invention of the present inventors, "a method for expanding or contracting a bundle of fibers and yarns" (U.S. Application Ser. No. 47775 filed on June 19, 1970) is one example of preferable methods. Said method is useful for uniformly spreading or converging a band comprised of a great numbers of filaments by the step of placing said band transversely across and between the turns of a coil spring of substantially uniform cross-section whereby the turns of the helix separate the filaments comprising the band into a plurality of portions, altering the distance between the turns of the helix to correspondingly enlarge or narrow the width of the band, and removing the band of adjusted width from contact with said coil spring. According to said method, the tow is extended to a larger width for the portion near the winding core, and the extended width of the tow is gradually narrowed with an increase in the winding diameter. That is to say, if the fibers or yarns are placed one upon another in a trapezoid form, a downward collapse of the edge part of the tow can be completely prevented. In any way, when a bundle tow is extended, the irregularity in the thickness of fibers along the entire extended width is sometimes increased to a considerable extent. In such a case, by making the thickness of the yarn-like material as large as 3,000 5,000 11., or by using a highly bulky yarn-like material and loosening a winding tension, the wound-up form can be kept in an almost cylindrical state, without causing winding deformation and collapse, even when about 100 kg of the layer having a width of 50 cm is wound up to a larger diameter of 70 cm. Further, unwinding can be carried out smoothly. Of course, when the thin layers of the fibers are unwound, the unwound yarn-like material can be reused, if it is wound onto a bobbin driven by a torque motor. The amount of the yarn-like material is, in most cases, less than I percent of the amount of a tow of fibers. Even when the recovered yarn-like material is thrown away, the packaging cost will be cheaper.

Now, explanation will be given to the case of filament yarns of Group (A) (2). In case of nylon, polyester, etc., the yarns after spinning are stretched and twisted yarn by yarn in a draw-twister and wound up onto bobbins, each yarn on each bobbin. Such a procedure has been heretofore used, but required much labor for doffing the bobbins. However, if 200 yarns are arranged in parallel at a pitch of 5 mm within a width of l m, stretched, thereafter heattreated and pasted with a polyvinyl alcohol type adhesive for each yarn to prepare parallel pasted cohered yarns and kg of the yarns are wound up in a parallel state of 200 yarns according to the present method in which the yarn-like material is inserted, the weight of each yarn becomes 500 g and it has a sufficient length for practical usages. Thus it will be a method for producing the yarns which requires considerably less labor than the conventional methods in which yarns are applied to a draw-twister which deals with yarns one by one. The yarns, which have been passed through the stretching at a width of l m, heat treatment, cohesion-by-pasting, and drying, can be wound up after being passed through a comb at a pitch of 5 mm for yarns one by one, where the comb is inclined by 60 from the parallel position to the winding core, so that the winding width becomes 50 em. if the angle of the comb is further increased with an increase in the winding diameter, the winding width can be properly narrowed from 50 cm to 40 cm. If the winding width is narrowed while inserting the yarn-like material into between the layers, no disadvantage of winding collapse at the edge part of the wound roll is brought about. Twisting can be applied to the yarns, if necessary, after the yarns are divided into 200 ends, and then wound up onto each bobbin.

The group (A) (3), (4), etc. are treated in the quite same manner as in the case of the group (A) (2). However, in the case of a split fiber web in a reticular structure and non-woven fabric prepared therefrom of the fibers are interconnected throughout the entire width to form a reticular structure and further, the non-woven fabric of laminated layers of their warps and wefts differs from ordinary filaments and yarns in fiber arrangement where there is no fear of winding deformation and edge collapse, even when the winding width is not narrowed with the increase in the winding diameter so long as they are wound according to the present method.

Also in the case of film system of the group (B) consisted of (6), (7), (8), etc., there is no fear of the edge collapse, and therefore, the layer is only plainly wound up at a definite width while inserting the yarn-like material into between the layers according to the present method. Even when there are large irregularities in thickness, the winding up of a long film-lilte material can be done easily by increasing the thickness of the yarn-like material, using a yarn having a high modulus of elasticity of bulkiness, and loosening winding tension. There is no trouble in the unwinding operation in the case of the film like material, but an irregularity corresponding to the thickness of the yarn-like material is apt to develop at the portion of the film, with which the yarn-like material is in contact. In this case, by passing the film over a heated drum and ironing it, the irregularity is removed by heat and a smoother film can be obtained. Therefore, when a stretched film is used as a base film for coating in the preparation of a synthetic paper, it is necessary to pass the base film over the heated drum and subject it to an ironing process for smoothening before coating for synthetic paper. Namely in the case of the coated synthetic paper manufacture, a base film roll wound as long as from 10,000 to several ten thousand meters is necessary for economical commercial production. Therefore a long base film wound up to a roll of large diameter according to the present invention, maybe subjected to an ironing process using a heated drum in a unwinding process to effect smoothening of irregular film for coating it in the next step. Thus the film of large wound diameter, which has been wound up according to the present method can be used without any trouble as a base film for the synthetic paper.

Further, in the case of a roll of small wound up diameter such as those of conventional products on market, for example, the wound up 1000 m long material, the film once wound up to a larger diameter according to the present invention is passed over a heated drum to form a flat film and then plainly wound up again to a smaller diameter of 1000 m-long material under a low winding tension according to the conventional method, whereby the winding can be effected without any irregularity of wound-up state even through there is a little irregularity in the thickness, and there is no fear of winding collapse. When the thin layer material is generally a fibrous product, it is, in many cases, sufficient that the winding width is 50 60 cm, the winding diameter is less than I m and the weight of one wound-up roll is about I00 kg, but when a biaxially stretched film is used as a base film for coated synthetic paper, the desirable width of the film is l to 2 m. Therefore, it is expected that the winding width becomes larger and the weight of one wound-up roll becomes 500 to I000 kg. if the apparent winding density of the wound-up layer is 0.75 at a winding width of 1.65 m and a winding diameter of 1.0 m with an inserted yarn-like material into between the layers, the weight of wound-up layer will be about one ton, and the film length be about 50,000m at an assumption of 20 g/m. There is no need of such along wound up length but, it can be used as a base film for a raw material in the coated synthetic paper manufacture by off-machine procedure sufficiently, so long as the layer has a length of at least 10,000 m, because the raw paper for the ordinary coat paper and the art paper is 6000 to 7000 m long.

As to the inclined crossing angle 9 of the yarn-like material, 9 can be changed in a wide range, depending upon the property and kind of the thin layer material, the property and kind of the yarn-like material, winding core diameter, wound-up diameter, etc. For the thin layer material of the group (A), a

relatively large an e is selected, and for the thin layer material of the group (B a relatively small angle is selected. Sometimes, an angle of 10 or less is employed. lt is not always necessary that the inclined crossing angle 0 be constant by one-round winding. For example, it is possible to make the inclined crossing angle larger at the start of winding-up to make the yarn-like material be less wound-up around the winding core. and then gradually make the angle smaller.

The inclined crossing angle 0 is determined by a relation between the winding speed of the thin layer material and the traversing speed of the yarn-like material. Further, the length of chord of the yarn-like material formed on the side face of the wound roll is determined by the excess degree of traversing, winding speed and traversing speed. Further, it is properly selected in view of the properties and kinds of the thin layer material, the properties and kinds of the yarn-like material, the diameter of the winding core, the winding diameter, etc.

What is claimed is:

1. An improved method for minimizing telescoping in the winding up of a broad width of thin layer material upon a winding core so as to thereby produce a large generally cylindrical roll which comprises:

a. continuously supplying an elongated continuous yarn-like material between I. the exterior surface of a layer of material that has just been wound and 2. the under surface of a layer that is about to be wound into face to face contact with said wound layer,

b. traversing said yarn-like material back and forth across the cylindrical surface portion of said material being wound, and

guiding said yarn-like material that has traversed the cylindrical surface portion in one direction across a portion of an end section of said cylindrical roll before said yarn-like material reverses its direction and traverses across the cylindrical surface portion of said material being wound in the opposite direction.

Claims

1. An improved method for minimizing telescoping in the winding up of a broad width of thin layer material upon a winding core so as to thereby produce a large generally cylindrical roll which comprises: a. continuously supplying an elongated continuous yarn-like material between 1. the exterior surface of a layer of material that has just been wound and 2. the under surface of a layer that is about to be wound into face to face contact with said wound layer, b. traversing said yarn-like material back and forth across the cylindrical surface portion of said material being wound, and c. guiding said yarn-like material that has traversed the cylindrical surface portion in one direction across a portion of an end section of said cylindrical roll before said yarnlike material reverses its direction and traverses across the cylindrical surface portion of said material being wound in the opposite direction.

2. the under surface of a layer that is about to be wound into face to face contact with said wound layer, b. traversing said yarn-like material back and forth across the cylindrical surface portion of said material being wound, and c. guiding said yarn-like material that has traversed the cylindrical surface portion in one direction across a portion of an end section of said cylindrical roll before said yarn-like material reverses its direction and traverses across the cylindrical surface portion of said material being wound in the opposite direction.