Process and apparatus for stretching a tubularly-formed sheet of a thermo-plastic material and the product produced thereby

MEMORY

POOR

QUALITY No. κ od β mimo * for VEISTS years conducted in Bepefíft in favor of ΒΖΛΧ-PiaWIL »CQRPSEAIXQS, of American nationality, domiciled in 1066

5. American Prive, Lícenah, Wieconein, U.3.A., by Procedure for longitudinally stretching a sheet forming it tubuleraente and corresponding apparatus, with priority of the US application 766,926 dated February 9, 1977. ---------- ---------------- io. iosoria psmfliyim

Bata invention does not refer to a new procobo and apparatus for the pulling of a tubularly formed sheet of taraoplaetic material and more pnrtículerne to a prooeso and a new apparatus for Diaxial stretching of

fifteen. a tubularly foamed sheet of an orienting tersopláati ee pelifflárieo material to form boleas of resistance to tensile rupture in improved strip. ------- Lae thermoplastic boleas for various uses, such as snack boleas, trash boleas, bowl20 "that for leaves and sirailaraa, are produced by extracting" tube

- 2 A tereoplast material, such as the polyethylene of the density and cooling · to the resulting tubular material sol. giving it tacitly and scratching or cutting to the desired length. The bag formed by this lamp exhibits a long tensile tensile break in the Sativa dam of the elaborated thermopiratory material. The end-use of the noplastoa woven bag usually provides for the eeleoeion of the thermoplastic material, for example, eatao bag for sandwiches * "eoc £ ge a thermoplastic material of low porosity and resistance10. normal wave while a garbage bag would demand the

BsleeoiÓn. of a thermoplastic material that exhibits characteristics of high resistance. ------------ It is an object of the present invention to provide a new process and apparatus for stretching a lamp15. Tennoeoldable tubular mine ds a material without a puppet. - - Another purpose of the present invention is to provide a new process and apparatus for biaxially stretching a sheet or strip of tubular and heat-weldable thermoplastic material in a crushed liner to form a bolus.

20, with an improved tensile strength in strip at least twice greater than the “faith, the tubular sheet of thermoplastic material being treated} effectively, providing a significant or unexpected result in the sense that it is the signal of Welding eats the do25 zone, softness increases sn resistance, in addition to the movie signal £

Other objects and various advantages The present invention will become apparent in the following detailed description of an exemplary embodiment of the same »ilustráadjs, in particular, the new features in the laws

5. annexed vindications. ----------------- It is agreed that the present invention provides a process and an apparatus for the selective stretching of a sheet or strip formed of thermoplastic material in a workstation equipped of a rc10 game. sub-sinusoidally grooved dilles »whereby the sheet or band of the tormopláetjL eo material is stretched in such a way that a uniform stretching is performed, thereby producing a sheet or band of greater dimension in the direction of stretching. ----------fifteen. According to a preferred embodiment of the present invention, a process and apparatus for biaxially stretching a sheet formed of tubular and tensile welded of thermoplastic material in a first workstation and a plurality of second workplaces are provided

twenty. in which the first and second positions are provided with sets of rollers provided with perpendicular grooves and strips, respectively, to the axis of each set of rollers. Fl grooved drawing of each roller set ee such that the distance between grooves is less than once (in tailíae25. Tros) the base weight of the sheet or band in grams per meter

- 4 square (g / m²) »The band limb <3 * tubular thermoplastic material and stretches a sound such that a" makes a uniform drawing to produce a teraoplastic reel of re alfitaneia to tensile rupture on eubstaneialewate strip

5, improved. ------------------------ The invention will be more alarming, with reference to the following detailed description of an exemplary realization of the myoma jointly with the loa Do you plan annexes in which »- - - - - - - - - - -10 · Figure 1 shows a side view of the apparatus and procedure of the present invention? and ------------------------ Figure 2 is a schematic upper wing of the apparatus and the procedure in this in15. vención ------- - · - - - - - - - - - Sn aras gives clarity and has omitted what sets of drive and support * synchronization and safety circuits and the like * known and used by the thocai eos «i the matter. -------------------twenty. With reference to Figure 1 * sa illustrates a realj ^

Preferred ration of the method and apparatus of the present invention which includes a set of circular blown aatris do pelí5 oulft and a stretch assembly, generally designated 10 and 12 respectively. The circular blown film matrix assembly 10 forming the copied film 12 can be any of the types of assembly

5. sold by the S-terling Extrudcr Corporation of South

Plninfield, New Jersey. The blown film 12 is made around the roller 14 to form a flat sheet 16 two layers before its introduction into the soldering iron assembly, indicated generally with 18, which is a

10. set known and used by those skilled in the art, or to which the two-layer sheet is welded at intervals chosen in a line perpendicular to the movement of the sheet 16. -------------- ---- Thus the sheet 20 of two layers and ter

fifteen. molded from sata to a first work station, generally indicated with "1 * between a pass 22 between a pair of rollers 24 provided with a plurality of grooves 26 formed perpendicularly to the axis of the rollers 24, such as see in figure 2. So keep the lamp20. mine 20 against the lower grooved roller 24 by means of a pair of pressure rollers 23 to hold the sheet 20 against the lower roller 24 so as to prevent the sheet 20 from narrowing even prior to its introduction. Once in the past 22, the sheet 20 adopts the

The shape of the groove pattern and is stretched according to a factor of the stretch ratio as described later in the present more clearly. ------------- 6 In the first place of work, in fact, eatjL a side slit, wind the SO sheet at the same speed as the feed speed. The crumpled drawing is flattened by pulling the sheet 30 lateralaent ·, for example by

5 »pinsao of teaaora branch or roller · curvea seftaladoe in general with 3? which are known and used by the experts in the field. --------------------- The groove · 36 of the roller · 34 is geared oono gear ·, as the technicians know in the kill. estuary. As the sheet 20 enters the loop 33, the line 30 takes the form of a groove 36 and is stretched by a factor determined by the length of the sine wave * of the groove divided by the original length of the band ^w& * between contact points of each «slot reata

fifteen. according to what is disclosed in the pendant US patent application n «serial 563.623» filed on March 31, 1975. --------------- The stretch ratio J is calculated / ω by the following equation doadei ---------------- at% d / 3 oj, and the sine wave of the groove ea i / y- «.

^v i + a oo »dx

0‘

twenty. Thus, for the ·· d / do 1.0, 1.75 and O »5» ratio, the · relationship · of stretching are 2.35, 2.0 and 1.6 respectively. - - - - A laterally stretched sheet 34 of the rollers 32 is passed through and passes through a passage 40 between a first pair of rollers 42 of a second position "11" te5. said rollers 42 allocating a plurality of grooves 44 parallel to the axis of the rollers 42. The sheet 32 ​​is held against the grooved lower roller 42 by a pair of presiding rollers 46 to ensure that the speed of the sheet 32 ​​is eubstantially identical to the speed

10. shallow V₁ of the remoted rollers 42. The grooves 44 of the rollers 42 are geared as gears, as known to those skilled in the art. When the sheet 34 penetrates the passage 40, the sheet 34 takes the form of a groove 44 and is stretched by a factor determined by the

fifteen. Sine wavelength "7" of the groove divided by original band length ^{M |}> between points of contact of each ridge with respect to the groove, as described above with reference to the blade of the sheet 20 through the rollers 24 dol placed I. ------ 29, plate 34 »deepuáe de its passage through the pass 40 between the rollers 42, dragged by a pair of tension rollers 43 with a superficial velocity V? greater than the surface speed of the rollers 42, but not greater than a factor of the draw ratio made in the

25. sin 40 between the rollers 42. ------------ 8

Cut also fearing, and the length of the sheet 34 increases by such factor. It is noted that the sheet 34 does not have an etching while it is stretched longitudinally, as is the case with the convention roller systems »

5. read. In a preferred embodiment of the present invention, the sheet 34 is passed through another "do" paree d "remotely rollers 42 in order to stretch the sheet 34 dinalsente length" dn more, which sheet is finally collected in a roller 50. -------------------- 10. You can terminate the maximum thinkable stretch ratio by measuring the residual elongation of the thermoplastic material. To improve # reeultadoe, the grooves 44 of the rollers 42 should be as thin as possible, increasing the distance between renurae and 0 must be oriented fac15. Toree of heavy basic step * From experience, we can see that the distance between slots »(in a») or less than 1.0 vocee the babe delgfnero (pn grams / m) is obtained with the procedure and the device of the invonolon present, and produces a bole with a length

twenty. of tensile breakage in strip (LRTX - expressed in meter ») much higher than a normal winding produced from blown film. ----------------- The operation of the procedure and the apparatus is described in the following examples that have an alloy

25. For illustrative purposes only and therefore not to be considered the invention as limited to loe mimaos. ---- 9

Example I

5.

One 7 x 7 inch (approx. 18 x 18 cm) double layer sheet is formed by extracting a mesol of a 90 / C polypropylene (melt flow regime of 0.5 g / β ») and a 10 / clay oon the following properties: ----- 10.

<td>Thickness 0.950</td><td>: 127 microns</td>

<td colspan="2">Λ base pit of the film; 125 g / m</td>

<td>L3RTÍ</td><td>$ 3570 to</td>

<td colspan="2">Elongation at break: $ 1600</td>

<td>Initial module</td><td>x 1600 π</td>

<td>ΙΗΪΙ about welding</td><td>l 2560 m</td>

<td>Ϊϊϊϊιϊϊϊϊ on doubles</td><td>: 3050 m</td>

It is thermo-welded and the bag is stretched in the device

1.5 times in a lateral direction and 3.3 times in a longitudinal direction (3 paeadae) has a definitive dimension of 19.5 inches wide by 23 inches long (approx., 26.70 x 58, 40 cm) It is also observed that the heat-welded tone is also ethereal. The stretched ball has the following properties: ------------------

<td>MU</td><td>: 23550 a</td>

<td colspan="2">Elongation at break: 40 /</td>

<td>Initial module</td><td>x 185500 a</td>

<td>LRTT on welding</td><td>: 15500 a</td>

<td>LRIT over doubles</td><td>: 16600 ia</td>

Example II

The procedure of Example I is repeated on a similar sheet of 18 x 1 "m being heat-welded after stretching, instead of before * the LRTÍ being over

5. the welding of 2200 m * that is to say sines that the tMSI on the welding of a welded coil before stretching · * Example ΠΙ

A 7 x 7 inch double layer sheet (eprox., 18 "15 cm) is formed by extruding a polypropylene at 10C ^

10. (flow rate in fustán of 6.0 g / 10 ra) and with the following properties: -------- - - - - - - - - 15.

Thickness 0.050 ”: Base weight of the film x LRTT i Elongation at break: Initial Kódttlo t LW on welding: LRTI on doubles:

130 miera »142 g / m²3200 at 1400 JÍ 14500 ffl 14500 «3040 m

The bag is heat welded and stretched in the apparatus 20. 1 * 5 times in a lateral direction and 4 * 5 vooea in a longitudinal direction (3 heavy) a final dimension of 10 * 5 inches wide by 31 * 5 inches is sufficient long (eprex. 26.70 x 80 cm). Ro observes that the heat-welded aona is also stretched. The stretched bag has the following »property» ® *

5.

Thickness * Base weight t LRO ϊ Elongation at break * Initial module: LKTT on welding »L8TÍ on bending and« loras 21 g / ra²

35700 ra (length) £

225000 n 18400 ss 22050 ® ¹⁰»S, iwsftojy

Pe forms a 7 x 7 inch (approx., 13 x 10 ca) double layer sheet spreading a 95 / high density polypropylene (2.0 g / 10 m melt flow regime) and a 5 / of titanium dioxide and eon laa ai15 »guìnte® properties * -------------- - - -

<td>Thickness</td><td>* 200 aloras</td>

<td>Base weight of the film</td><td>: 170 g / tn²</td>

<td>Lew</td><td>s 3800 ra</td>

<td colspan="2">Elongation at break * 1800 /</td>

<td>Initial module</td><td>i 12000 ra</td>

<td>LRIT on welding</td><td>s 2600 ra</td>

<td>LRTT on doubles</td><td>: 2650 a</td>

3 · teraoouelda and ee catira the bolea in the aparate 2.0 vece® (two passes) in a lateral direction and 5.0 ve12 Cea in a * direction, longitudinal (3 passes) to a final dimension ds 14.0 inches ds width for 25 inches ds 1 »£ go (approx., 35 * 6 for £ 3 * 5 or») · It is observed that the teraosoidada trembling aona is stretched, has stretched bag has

5. The following properties -------------- 10.

Thickness and base Peco »LRTI» Elongation at break t Initial module »LKIT on tolling t LRTT on double» &lt;

honey 13 g / »²

33500 » £

17500 to 28500 »30400 a

This is easily apparent to a technician in the category who produces a new light weight bag that is fun15. tion of its dimension that exhibits substantially a length of tensile breakage in a «garlic-coated strip. It will be readily apparent to a person skilled in the art * that, depending on the end use *, the bag of improved tensile length can be produced by passing a temo foil20. tubularly formed plastic, preferably heat welded * either through the laterally grooved rollers or gonorinalaente or seouenoialaente through such grooved rollers or til ooao is described in the patent or reference to the preferred realization. --------- 25.

While the invention has been described in connection with an exemplary embodiment of the alema »it will be understood that sucha» modifications will be apparent »to those skilled in the art and that this application is intended to cover any adaptations or variations thereof. - - - - 5. For the following purposes, they declare that they are new and owned by ISepeSa, its territories and countries of Sobara Nía, the