US3514368A - Laminated plastic yarns and method and apparatus for making the same - Google Patents

Description

May 26, 1970 J. NETSEL LAMINATED PLASTIC YARNS AND METHOD AND APPARATUS FOR MAKING THE SAME 2 Sheets-Sheet 1 Original Filed Feb. 19, 1965 Q JM Q R R g R N wm wm m.

MOE

INVENTOR. JOSEPH NETSEL A TTORNE Y.

y 6, 1970 J. NETSEL 3,514,368

LAMINATED PLASTIC YARNS AND METHOD AND APPARATUS FOR MAKING THE SAME Original Filed Feb. 19, 1965 2 Sheets-Sheet 2 INVENTOR.

JOSEPH NETSEL no.9 BY

ATTORNEY:

United States Patent 3,514,368 LAMINATED PLASTIC YARNS AND METHOD AND APPARATUS FOR MAKING THE SAME Joseph Netsel, Providence, R.I., assignor to Acme Backing Corporation, Stamford, Conn., a corporation of New York Continuation of application Ser. No. 433,983, Feb. 19,

1965. This application Mar. 27, 1968, Ser. No. 716,666 Int. Cl. D02g 3/00 US. Cl. 161-177 12 Claims ABSTRACT OF THE DISCLOSURE A laminated plastic yarn formed from film having longitudinal prescored fold lines to insure in the folded yarn precise, uniform width and thickness of the yarn throughout the length thereof; together with a method and apparatus for forming the same.

This application is a continuation of applicants copending application Ser. No. 433,983 filed Feb. 19, 1965, now abandoned.

Conventional plastic yarns of the laminated type, which are formed by folding the opposite lateral portions toward each other over a central portion, have a tendency to vary in width along the length thereof and may also vary in thickness at various points along the length thereof, due to changes in the disposition of the individual laminae of the yarn.

Such irregularities in conventional plastic yarns not only interfere with the usual textile weaving and finishing operations in converting such yarns into fabric, but necessarily require special techniques and adjustments in the manufacture of fabrics utilizing such yarns. Also textile fabric designs are compelled to recognize the shortcomings of this type of fiat yarns and must compensate for the same.

Accordingly, an object of this invention is to provide an improved multi-ply flat plastic yarn having a precise Z fold construction which insures uniformity of width of the yarn throughout its length, as well as uniformity of ply disposition and thickness.

Still another object of this invention is to provide an improved method and apparatus for converting plastic film of a selected gauge into multiply yarns which have a precise uniform width and thickness throughout the length thereof.

Yet another object of this invention is to provide an improved fiat monofilament textile yarn of superior tensile strength with a low specific gravity, which lends itself to the manufacture of a variety of types of fabric and particularly as warp elements in drapery fabrics and the like.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

In the drawing:

FIG. 1 is a plan view showing the progressive conversion of plastic web into yarns embodying the invention;

FIG. 2 is a side elevational view showing the apparatus and procedure embodying the invention;

FIG. 3 is a front elevational view showing the slitterscoring assembly of said apparatus;

FIG. 4 is an end elevational view thereof;

FIG. 5 is an enlarged sectional view showing the meshing slitting-scoring discs;

FIG. 6 is an enlarged sectional view showing the slit and scored strip issuing from said assembly;

FIG. 7 is a side elevational view of the folder of said apparatus;

FIG. 8 is an end view thereof; and

FIG. 9 is a transverse sectional view showing the finished yarn embodying the invention.

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Essentially, the yarn of the instant invention is derived from a thermoplastic film or web of selected gauge and width, which is processed in a continuous manner by slitting the same into laterally related strips, simultaneously scoring the strips, folding the scored strips by a Z fold into a three-ply laminate, which is then heated, stretched and tensilized to form the finished yarn of precise uniform width and thickness.

Thus, as shown in FIG. 1, 10 designates a plastic film or web of selected gauge and width, preferably derived from a polyolefin resin such as polypropylene. Film 10 is continuously slit along parallel lines 11 to form laterally related individual strips 12 which are simultaneously scored longitudinally along a pair of parallel, equally spaced longitudinal lines 13.

Strip 12 having two score lines 13 allow the same to be folded in Z fashion to form a 3-ply laminate indicated at 14. The laminated strip 14 is then stretched at a controlled temperature, reducing the strip to a selected width and thickness and converted to the final multi-ply monofilament yarn 15.

As indicated in FIG. 2, yarns 15 may be produced in a continuous manner, from thermoplastic film or web 10 of selected gauge which is provided on a reel 16 suitably mounted on a horizontal axis for movement in a longitudinal path through successive processing elements. Thus, the film 10 is fed from reel 16 to tensioning means 17 comprising a pair of opposed felt members 18, 19, where one of said members is held in a fixed horizontal position and the other member is mounted for adjusted movement toward the fixed member to thereby vary the tensioning action on the film moving between said tension members 18, 19.

The tensioned plastic film then passes to a web guide comprising a pair of vertically disposed plates 20 adjustably mounted in spaced relation on a guide bar 21, to engage the side edges of said film or web 10 to direct the same in a given path around a guide roller 22 and thence to a slitting and scoring roller assembly 23, hereinafter described in detail, where the film 10 is slit to form strips 12 and simultaneously scored to form score lines 13 therein.

The leading ends of strips 12 are hand folded in a Z fashion along said score lines 13 and introduced into folder means 24 where the folding operation thereafter takes place in a continuous manner. The folded strips 14 issuing from folder 24 are moved by driven pull rollers 25 operating at a surface speed slightly greater than the surface speed of the slitter-scorer roller assembly 23.

From the pull rollers 25, the strips 14 pass over a heated platen 26 at a temperature of about 235 F., the strips having moving surface contact with said platen. The heated strips then pass to a second set of pull rollers 27 which have a surface speed which is 400% to 725% greater than that of puller rollers v25, whereby the strips 14 are stretched and reduced in width and thickness to selected dimensions to form the yarns 15.

The yarns 15 then pass through chamber 28 heated by forced hot air at a temperature of about -185 F., by way of a guide roller 29 in said chamber, to pull rollers 30 which have a surface speed of about 2% less than that of pull rollers 27 to allow the yarns to recover before the same are wound on bobbins, reels, pirns, or the like, not shown.

The slitter-scorer assembly 23, as shown in FIGS. 3-5, is adapted to slit film 10 continuously into strips 12, which strips are simultaneously scored to provide score lines 13 which permit the strips 12 to be folded in Z form. Accordingly assembly 23 comprises a pair of parallel, horizontally disposed shafts 31, 32 arranged to be driven, by means not shown. On the shafts 31, 3-2 are mounted a series of spaced slitting and scoring discs in meshing relation adapted to slit film at equally spaced intervals along the width thereof and to simultaneously score the slit web portions at equally spaced transverse intervals to divide each of said strips into a pair of outer zones and an intermediate zone, all of equal width.

To this end, there is mounted on the left hand end of the upper shaft 31, a square edge slitter disc 33, followed by spacer discs 34 of equal width and alternating with either bevel edge slitter-scorer discs 35 or square edge slitter-scorer discs 36 in a predetermined sequence. Similarly, on the lower shaft 32 there is mounted on the left hand end thereof, a square edge slitter-scorer disc 37, followed by spacer discs 34 which alternate with bevel edge slitter-scorer discs 38 similar to discs 35 or additional square edge slitter-scorer discs 37 similar to discs 36 and terminating at the right hand end thereof with a square edge slitter disc 39.

Each of the discs 35, 38 is bevelled at one edge 40, 41, respectively, at an angle of about while the other edges 42, 43 respectively are left in squared condition. The bevel edges 40, 41 have a width of about .003" on the face edge of discs 35, 38 and a depth of about .010 on the one side thereof. The discs 35, 36 on shaft 31 intermesh with discs 37, 38 on shaft 32 to an extent determined by the gauge of the web 10 passing therethrough. By way of example, the discs may mesh to an extent of about .010" to allow for slitting and scoring the film 10.

It will be apparent from a consideration of FIG. 5 that discs 35, 36, 37 and 38 are arranged in successive assemblies along shafts 31, 32 so that coacting square edges will effect a slitting action while a square edge coacting with a bevel edge through a small clearance therebetween will effect a scoring action, which is limited to about /3 to /2 the thickness of the film 10. Thus, starting at the left hand end of shafts 31, 32, discs 33, 37 coact to slit and trim the left hand edge of web 10; the square edge of disc 37 and bevelled edge 40 of disc 35 form a first score line 13A on one side of the film 10 and the square edge 42 of disc 35 and the beveled edge 41 of disc 38 form the second score line 13B on the other side of film 10. The square edge of disc 38 and the square edge of disc 36 slit the web 10* to thus provide the first scored strip 12. The square edge of said disc 36 and the adjacent bevel edge 41 of adjacent disc 37 again forms a score line in the next strip 12 and this is repeated throughout the width of web 10 with successive slitting actions and intermediate scoring effects, until the square edge of the last disc 35 on shaft 31 coacts with the square edge of disc 39 on shaft 32 to slit and trim the right hand side edge of web 10.

Obviously, the width of spacer discs 34 will determine the spacing between score lines 13. As the slit and scored strips 12 issue from assembly 23, said strips will be preconditioned by score lines 13A, 13B, FIG. 6 to facilitate a Z fold of lateral zone A toward one side of intermediate zone B while the other lateral zone C is folded toward the other side of intermediate zone B, which folding action takes place in a continuous manner in folding means 24.

As shown in FIGS. 8, 9, said folding means comprises a pair of opposed plates 50, 51 held together by bolts 52. The lower plate 51 is formed with a shallow recess 53 on its upper surface, thereby providing a through slot 54 between plates 50, 51 extending between the front and rear edges thereof. Slot 54 is of a depth to pass the three-ply strip 14 as the same passes from assembly 23, and to bring zones A, C into intimate fiat contact with intermediate zone B thereof. The forward edges of plates 50, 51 may be slightly beveled at slot 54 to facilitate the entry of strips 14 therein. The depth of slot 54 may be about 50% greater than the thickness of entering strip 14. The surfaces forming slot 54 should be highly polished.

The film 10, when formed of polypropylene, may be processed at speeds of up to 5060 yards per minute, and platen temperatures of 230 to 240 F., preferably 235 F. were found to be effective in producing a desirable flat yarn 15. The web 10 may have a gauge of .0015" but such gauge may be .001" or greater.

While the process herein disclosed is particularly effective when using films or webs of polypropylene, it is understood that other plastic films derived from polyethylene poly vinyl chloride, polystyrene, etc. may be similarly slit, scored and Z folded to form multiply yarns of uniform width and thickness. Platen temperatures would be adjusted in accordance with the resin used.

By way of illustration, strips 14 may have a width of about .062" and upon stretch yarns 15 may have a reduced width of about .028".

As various changes might be made in the embodiments of the invention herein disclosed without departing from the spirit thereof, it is understood that all matter herein shown or described shall be deemed illustrative and not limiting except as set forth in the appended claims.

What is claimed is:

1. A flat, multi-ply plastic monofilament yarn comprising a strip prescored along spaced longitudinal lines to provide a longitudinally extending intermediate portion and a lateral portion on each side of said intermediate portion, said portions being of substantially equal width, one of said later portions being folded on one of said score lines into contact with one surface of said intermediate portion, the other of said lateral portions being folded on another of said score lines into contact with the other surface of said intermediate portion, said yarn being of uniform width and uniform thickness throughout the length thereof.

2. A multi-ply yarn as in claim 1 wherein said plastic is polypropylene.

' 3. A three ply flat yarn formed from a folded plastic strip having a Z fold cross section with the free longitudinal edge of one outer ply substantially extending to one folded edge of the intermediate ply and the free longitudinal edge of the other outer ply substantially extending to the other folded edge of said intermediate ply, said yarn being of uniform width between the free edges of said outer plies throughout the length thereof.

4. A flat yarn as in claim 3 wherein said strip is prescored along lines at the juncture of the opposite edges of said intermediate ply with said outer plies.

5. A flat yarn as in claim 4 wherein said prescore lines are respectively on opposite sides of said strip.

6. A method of forming multi-ply flat yarns comprising slitting a plastic film into a plurality of strips, scoring each strip along transversely and equally spaced longitudinal lines to provide an intermediate portion therein and lateral portions on either side of said intermediate portion, folding the lateral portions of each strip along said score lines respectively into contact with opposite sides of said intermediate portion, heating said folded strips and longitudinally stretching the folded, heated strip.

7. A method as in claim 6 wherein said plastic film is polypropylene and said folded strips are heated to a temperature of about 235 F.

8. A method as in claim 7 wherein said heated folded strip is stretched from about 400% to about 725%.

9. A method as in claim 6 wherein said slitting and scoring operations are simultaneous.

10. A method of forming flat yarns comprising scoring a thin strip of plastic material along a pair of transversely spaced longitudinal lines therein to provide a longitudinally extending intermediate portion and a pair of longitudinally extending lateral portions respectively on either side of said intermediate portion, folding the lateral portions of said strip along said score lines respectively into contact with opposite sides of said intermediate portion, heating said folded strip and longitudinally stretching the folded, heated strip.

11. Apparatus for forming multi-ply flat yarns from a thin film of thermoplastic resin comprising means for slitting said film into a plurality of strips, means for scoring each strip longitudinally along a pair of parallel lines respectively on opposite sides thereof, means for folding each strip along the score lines thereof to bring longitudinally extending laterally disposed portions respectively into contact with the opposite sides of an intermediate portion thereof, means for heating the folded strips and means for longitudinally stretching said heated strips to reduce the width thereof to a predetermined dimension uniform throughout the length thereof.

12. Apparatus as in claim 11 wherein said slitting and scoring means comprises a pair of parallel, horizontally disposed shafts, a plurality of slitting-scoring discs and spacer discs in alternating relation on each of said shafts, each of said slitting-scoring discs having at least one square peripheral edge, some of said slitting-scoring discs having one beveled peripheral edge, the slitting-scoring References Cited UNITED STATES PATENTS 2,541,141 2/1951 Brandt 161107 2,985,503 5/1961 Becker 264-147 XR ROBERT F. BURNETT, Primary Examiner R. O. LINKER, JR., Assistant Examiner US. Cl. X.R.

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