DE1704542A1 - New elastic polymer films and processes for their production - Google Patents

Description

Dr-In ₉ , from Krefcier Dr.-Ing. ScJrönwaW i / U -f O * t Z DrJno. Th. Meyer Dr. Fms Mt *, DtIdMMlMiMW

August 10, 196? Ke / Λχ

522_ Fifths Avenue ^ New. York,. N. Y .. 100 ^ "(U.S ../ LJU.

i s che_ polymer f oil i en_ and ^ ancestor cn ^ to ^ her he Manufacturing

" i

The invention relates to elastic films made of crystalline Polymers.,

It has already been proposed, her2ustcllon films of crystalline polymers, such as _e polypropylene by extrusion of the molten material and · cooling. These films have many excellent properties, such as high strength, stability and rigidity. A completely new type of film was found that in contrast to the films bekannton a high ElastizitKtsgrad after a relatively strong stretching beispielsv / Eiso to 5Q # or more at 21 ⁰ C

as well as numerous other unique and beneficial (

Has properties.

The invention, accordingly, new ^y elastic films known in their Eigenschafton films are superior, and a method for producing these elastic films.

j The invention is described below in connection with the Illustrations described.

Fig. 1 i £ t oino schematic representation showing the Ancestor of the invention, namely extrusion illustrated by oino wide slot nozzle on oino application roller. '

Pig. 2 schematically shows another mode of operation for Carrying out the process using the combined extrusion-blow molding process

According to one aspect, the invention relates to films made of one relatively crystalline film-forming polymers which, if they have a standard tension (elongation) of 50 # under-grains an elastic recovery or resilience of at least about 70 #, preferably at least about 8O # at zero springback time (according to the following Definition) at 25 ° C and 65 # relative humidity to have".

It should be noted that although a standard stress from $ 50 is needed to get the elastic properties lcr products according to the invention to be determined ^, however this elongation is only given as an example - the films of course generally have even higher elongations below 50 $ elastic recoveries than at a 50 # stretch, and their elastic rebound when stretching significantly more than 50 #, e.g. 100 #, is also relatively high.

The films according to the invention must be distinguished from films made from classic elastomers Stress expansion prelialtciij, in particular the stress-temperature relationship, dominated by an entropy mechanism of deformation (cummiolasticity). The positive one Temperature coefficient of the contraction force, i.e. the decreasing stress with decreasing temperature and complete loss of elastic properties in the Freezing temperatures are special consequences of the entropy elasticity. The elasticity of the films according to the invention, on the other hand, is of a different nature. In the case of qualitative thermodynamic ones Experiments with the foils according to the invention can lead to increasing tension with decreasing temperature

982 7 / '? 309 ^: '
ORIGINAL

■ negative temperature coefficient) was designed so that the elasticity of these films was not controlled by entropy effects, but depended on an energy level. Even more significant is the made determination that "the erfindungsgetnäßen foils their" keep elastic elongation "at temperatures at which the entropy elasticity could no longer be effective. For example, to keep the high molecular weight Acetalpolymercn according to the invention, its elastic strain at -78 ⁰ C, a temperature far below the freezing range (-J10 ° to -60 ° C). Furthermore, it was found that certain polypropylon films from an elongation of 50 $ at -86 ° C an elastic springback of 70 # or ir.ehr, preferably from 70 to 80 # It can thus be concluded that the mechanism of elastic behavior ( ^tf stretch "-Hechanisir.us; of the films according to the invention is based on energetic elasticity and the elastomers can be referred to as" non-classical "elastomers.

The invention is based on the finding that the The properties described above by using a crucial combination of process variables and process stages can be achieved. The necessary ancestral stages include molding, i. Extrusion of the foils under crucial conditions with subsequent tempering, which gives the desired degree of sluggishness. The following procedural conditions are necessary: l) high take-off speed, 2) high take-off ratio and 3) low temperature of the Melt, i.e. a temperature of the melt that is much closer to the melting temperature of the fum-forming Polymers than with conventional extrusion processes.

The high withdrawal speed can, for example, be achieved by using the take-up reel or spool for the

1098-21 / 1909

SAD ORIGINAL

extruded film is arranged at a distance of at most 5.1 cm, preferably at most 2.5 cm from the opening of the slot die. At the same time, the take-up roll must run at high speed, e.g. a speed of the film of 1.6 m / minute, measured on the roller blind, since the take-off speed of the film when exiting the nozzle (where the film is relatively thick) and on the take-up roll ( where the film is comparatively, thinner) is actually different.

^ Deduction ratios are expediently applied up to to 1000 ;! and preferably in the range of about 75: 1 to 125: 1.

The temperature of the extruded melt is generally not higher than 10O ⁰ C above the melting point of the polymer, most expediently in the range from 10 to ² JO ^{0 C above this melting point, while the draw-off} ratio in extrusion, ie the ratio of the linear speed of the winding roller to linear extrusion gas speed, at least 20 ι 1. The heat treatment is generally carried out at a temperature in Eercich of about 5 to 100 ⁰ C below the melting point of the polymers k for a period of at least 5 seconds. The annealing can be carried out while the film is in the untensioned state or in the slightly tensioned state, as is the case with continuous annealing.

As already mentioned, the elastic foils exist according to The material consists of a type of polymer which has an essential Able to develop degree of crystallinity in contrast to the more common elastic materials, e.g. Rubber that-in the unstretched or tension-free state is essentially amorphous.

An important group of polymers to which the invention is based is anvrcndbai *, the olefin polymers, e.g. polypropylene,

1098 * 21/1909

OADOfMGlNAL

Poly-3-ir.ethylbutene-1, poly - ^ - ir.ethylpenton-i, polyethylene and copolymers of propylene, 3-kothylbutene-1, 4-methylpentene-1 or ethylene with one another or with small amounts of other olefins, Z ₀ B ₀ copolymers of propylene and ethylene, copolymers of a larger amount of 3-methylbutene-1 and a smaller amount of a high-chain n-alkone, such as n-octene-Ij η-hexene !, n-hexadscene-1, n-octadecene -i, or other relatively long-chain alkenes, as well as copolymers of methylpentene-1 and any n-alkynes of the group mentioned above in connection with 5-methylbutene-1. In the form of films, these polymers generally have a crystallinity of at least $ 0 $, for example 5Q ~ 6O #.

Another group of polymers to which the invention can be applied are the high molecular weight acotal polymers. Acetal (or oxymethylene) homopolymers are suitable, but a "random" Oxymethylcncopolymeres is preferred as the Oxymethylcncopolymeres, ie a Copolyrceres the recurring Oxymethylcnoinhciten, ie units of the Porir.ol -CH ₂ O- with interspersed OR groups in the Contains polymer main chain, where R is a divalent radical containing at least two carbon atoms that are directly bonded to each other and are in the chain between the two valences, any substituents on the grate R being inert, ie containing no disruptive functional groups and no undesired reactions and in which the greater number of the -OR- units are present as units bound to oxymethylone groups on each side. Eeispicle of preferred polymers are the Copolyir.ercn of trioxane and cyclic ethers, which contain at least two adjacent carbon atoms ©, ζ.B-. the copolymers described in U.S. Patent No. 5,027,352. These polymers in polionic form also have a crystallinity of at least 505 », for example from 50 to 60 #.

109 8-2 1/190 9

8AD

Other relatively crystalline polymers to which the Invention is applicable, are polyethylene sulfide, polyamides, ζ, Βο polyhexamethylcnadipamide (nylon 66} and poly caproiactain (nylon 6), and polyester, e.g. polyethylene terephthalate,

The devices which are suitable for producing the films according to the invention are generally known. For example, a film extruder is sufficient, which is provided with a Hoir.ogenisicrschneckt with shallow flight depth and "coat hanger" - W nozzle, as shown in FIG. 1. With this arrangement, the resin is filled into the feed hopper 1 of the extruder 2, which contains a screw 3 and a jacket provided with heating elements 4. The resin is melted and transported by the screw into the extrusion die 5, from which it is pressed through the slot 6 in the form of a film 7 which is pulled off by the winding roller 8. Of course, several take-up rollers can be used in various combinations «

In an arrangement of this type, films can be extruded with a draw-off ratio of about 30: 1 to 1000: 1, preferably from 75: 1 to 125: 1 ₃ . The nozzle P opening or slot circuit can, for example, be in the range of Ο.76 to 5 mm. Polypropylene can be extruded at a melt temperature of ISO to 2 ² JO ⁰ C, preferably from 200 to 25 ° C, while acetal polyrr.oro, for example of the type described in US Pat. No. 3,027,352, at a temperature of Melt from 165 to 240 ° C, preferably from 200 to 215 C, can be extruded. Polyethylene can be extruded from 175 to 225 ° C at oinov Temporary Cordon.

E_: inI woijcntli.; H within the scope of the invention, Ua) extrusion tn :. ' rapid cooling and rapid Afc-ug bygc ^r - ^{: i;} ^ i » ^ - na.cin: ale blasti .l .-. v.- :: u achieve. This can

1.09 * 2 1/19110

8ADORiGtNAL

can be achieved in that the take-up roll is relatively 'close to the nozzle outlet., For example with a distance of up to 5 orn, preferably 2.5 cm, is arranged and rotated as quickly as possible without breaking the film.

An "air brush" can be placed at a distance of up to 2.5 cm from the slot be used. The speed of rotation of the take-up roll can be, for example, 6 to 305 m / min., Preferably 15 to 152 m / minute.

Another process for the production of the films according to the invention is the combined extrusion-blow molding process, "

which is illustrated in Fig. 2, where the hopper 1 and the extruder 2 are practically identical to the slotted extruder shown in Fig. 1. From the extruder, the melt arrives at the injection molding tool 10 - from which it is pressed through the dog slit 11 to form the tubular film 12 with your initial diameter D ^. Air is introduced through the inlet IJ and passed through the air ring i ^ 6d £ .A \ öh'e opening in this ring into the interior of the tubular film 12, whereby the tubular film is inflated to the diameter Dg. A -Next airflow, lh introduced into the air distribution ring through the inlet 16 and this air ring | distributed so that the air strikes the outside of the hot tubular film 12 and causes the necessary rapid cooling. After a certain running distance, during which the film is allowed to cool and harden completely, it is wound onto the take-up roll 16.

When using the blow molding process, the deduction ratio is preferably 20: 1000, the width of the slot nozzle 0.5 to 5 mm, the ratio Dg / Dj .0.5: 6.0 and the Wind-up speed 7.6 to 313 ft / ml. The temperature the melt can lie in the areas described above for extrusion with straight slot dies were called.

1098-21 / 1909;

ORIGINAL

As already mentioned, the extruded sheet must be tempered in order to develop the desired elasticity range. In general, the tempering is carried out at a temperature in the range from about 5 to 100 ^° C. below the crystalline melting point of the polymer for a period of at least 5 seconds. For example, the preferred annealing temperature for polypropylene is about 100 to 155 ° C, for oxymethylene copolymers (acetal) is about 110-165 ⁰ C and for polyethylene about ICO to 150 ⁰ C ₀

According to one of the possible methods, the tempering is carried out with hot rollers, whereby the tempering time is im is generally in the range of * about 5 to 90 seconds » Another method is to place the film in a tension-free state in a heating cabinet at the desired temperature held. In this case, a dwell time is preferred applied in the range of 5 minutes to 1 hour »

The invention enables the production of polypropylene films which * at 25 ^° C. and 65 % relative humidity have a springback or elastic recovery from 50 % elongation of 85 to 95 %, a tensile strength of 387 to 527 kg / cm ² , an elongation at break of 250 up to 35O %, have a modulus of I7.6OC to 24,600 kg / cm (all values mentioned are measured in the machine or longitudinal direction). The other properties of these polypropylene films are generally within the following ranges: density 0.88 to 0.91 g / cm, haze 5 to 15 %, moisture vapor permeability 1 to 100 g / 24 hours / m / atm., An oxygen permeability of 2000 to 3OOO, a nitrogen permeability of 500 to 700 and a ^ permeability of 8000 to 9500 cm- ⁵ /24 hours / m ² / atm "

Films made from oxymethylene copolymers according to the invention (or acetal copolymers), e.g. B. those in the U.S.A. patent 3,027,352 described polymers, generally have the following properties in longitudinal

1 £) 38'21 / AS BATH ORIGINAL

direction at 25 ° C and 65% relative humidity: elastic recovery to 3I.6OO kg / cm "have aus.50% elongation tensile strength of 85 to 99 $$ 56o to 700 kg / cm ^2, elongation at break 100-150 $, 28,100 Furthermore module such films generally have a density of 1.36 to 1.41, a haze of 5 to 15 $>, a moisture vapor permeability of 300 to 450 g / 24 hours / m / atm. and an oxygen permeability of 2CO to 400, a nitrogen permeability of 100 to 200 and a (^ permeability of 6000 to 13,000 ml / 24 hours /.

P '' ■ ■ * - '■■■■■ ..' · ■. ■ '■■' ■ · ■■ "■■ '■■■ · ■' · ^N ■:

m / atm. -:

The films according to the invention thus have much higher Springback or elastic recovery than usual foils, ™

which are produced by the known methods, while their elongations at break are somewhat lower than these usual foils. . = i

Example 1. . ^:

The forming polymer of this example was a copolymer of trioxane and, based on the weight of the polymer, 2% ethylene oxide. It had a melt index, of 2.5. It was post-treated to remove unstable groups in the manner described in U.S. Patent 3,219,623 and appropriately stabilized. ^!

and belonged to the copolyir. type used in the U.S; A. ~ f Patent Specification 3,027,352 is described 1st.

This polymer was 19I at ⁰ C by a 20.32 cm wide slit die of the type shown in Fig. 1 at a shear rate of about ^l \ 6 reciprocal seconds, using a 2.54 em-Extrudera, extruded, the feed screw with a low Aisle depth was provided. The length / diameter ratio of the cylinder of the extruder was 24: 1. The strand was drawn off very quickly with a draw-off ratio of 270: 1 and brought into contact with a rotating casting roll which was kept at 143 ° C

109821/1909

- ^ h .;. · ■ - :%? ΘΛΟ OFWGINAt

and was less than 6.35 mm from the nozzle outlet. The film produced in this way was wound up. It had the following properties: Jbicke 13yu

Springback of $ 50 elongation $ 46

The film was annealed for 1.5 hours at 15O ⁰ C in the stress-free state. It was then taken out of the warming cabinet and left to cool, after which it had the following properties:

Thickness 13 p

Springback from $ 50 stretching

the first stretch $ 90

Springback from $ 50 stretching

the fifth stretch is $ 78

Springback from $ 100 stretching
the. first stretch

The polymer described in Example 1 was extruded at 204 ° C. through a 20.32 cra-flashing nozzle of the type shown in FIG. 1 with a 44.5 mm extruder which was provided with a horco-whirling screw of the type shown in FIG was. The length / diameter ratio of the cylinder of the extruder was 24: "I. Per strand, was drawn off quickly with a draw-off ratio of 120: 1 and taken up by a rotating casting roll, which was set at 132 ⁰ C and at a distance of about 6 mm from The film produced in this way was wound up and at this point had the following properties: Thickness, 23 ix

Resilience of 50 $ D _e hnung at 25 ⁰ C 44 $

The film was then tempered in the tension-free state at 145 ^° C. for 1 hour. It was taken from the warming cabinet and left to cool. 'She had the following characteristics:

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BATH ORIGINAL

Thickness 23

Springback from $ 50 stretching after the first stretch

Springback from $ 50 stretching
the fifth stretch

Springback from $ 100 elongation $ 82

After the film was stretched by five times $ 50, she was again the power is disconnected at 14O ⁰ C for 1 minute annealed in an oven * She was then removed from the oven and allowed to cool, whereupon they had the following characteristics:. ■

Resilience of $ 50 after the first stretching D _e hnung 88 $ 50 $ resilience of stretching in the fifth stretching $ 74

The polymer described in Example 1 was based on the in Example 2 described way extruded with the difference that the draw ratio was 50: 1. Open up wrap the film had the following properties: thickness, 53.3 m

Springback from $ 50 stretching $ 40

The film was then heated in a tension-free state for 2 hours at 149 ^° C. in a heating cabinet. It was taken out of the ■ warming cabinet and left to cool down and now had the following properties: -. Thick. 53.3

Springback from $ 50 stretch after first stretching $ 84 Springback from $ 50 stretching after the second stretching $ 80

The polymer used in this example was that in Example 1 described similar t the difference that it is a terpolymer of trioxane, 2 $ ethylene oxide and 1 $ Fentaerythritol was formal and a melt index of 0.5 would have. This polymer was at 204 ° C through a 8 "slot die of the type shown in Figd with a 44..5 mm extruder extruded; the one with a Hcmogonisior-

109821/1909

ORIGINAL

screw was provided with a shallow flight depth. The length / The diameter ratio of the cylinder of the extruder "was 24: 1 o The strand was fast at a withdrawal ratio deducted from 200: 1, via a rotating, at 141 ° C held casting roll guided and then wound up ». At this point in time, the film had the following properties: Thickness 20.3 / J.

Springback from $ 50 stretching $ 50

The film was then annealed 1.5 hours in an oven at 150 ⁰ C, removed from the cabinet and allowed to cool. It now had the following properties: Thickness 20.3 a.

Springback from $ 50, stretching $ 94

Springback from $ 100 stretch. $ 87

Example ^

Crystalline polypropylene, which had a melt index of 4jO and a density of 0.305 g / cm., Was extruded at 193 ° C. through a 20.32 cm slot die of the type shown in FIG metering screw with a low junction depth had the length / diameter ratio was of the cylinder of the extruder 24: 1 "the strand was very fast at a rate from :: ugsverhältnis of 90: peeled 1 and brought into contact with a rotating casting roll in contact, the at 85 ⁰ C and held at a distance of 6.4 mm from the exit orifice of the nozzle. The film produced in this way had the following properties:

Thickness 25.4 m

Springback from $ 50 stretching $ 49

The film was then annealed in a stress-free state 45 minutes in oven at 140 ⁰ C. It was taken out of the cupboard and left to cool. It had the following characteristics «

109 82 1/1909

.JWiulKO ÖA £ * BAD ORIGINAL

Density 0.908 g / era ³

Springback ana 5C $ stretching after the

first stretch. ■■ · .. · 945 »·

Springback from $ 50 stretching after the

fifth stretch 84,

Springback from 5O # stretching after the

tenth stretch. 77

Springback from $ 50 stretching after the twentieth stretch ', 74, springback from $ 50 stretch after the first stretch

After the! Film was stretched to twenty 50 #, it was annealed again when no voltage is 3 minutes in an oven at 135 ⁰ C, taken from the oven and allowed to cool. It now had the following properties:

Springback at 50 $ stretching at 25 ⁰ C after the first stretch

Springback at 50 $ 6 stretching at 25 ⁰ C after the fifth stretch

Ee is noteworthy that the density of the material according to the first anneal, i.e. 908 g / cm, is representative of a highly crystalline material.

The polymer described in Example 5 was extruded at 228 ⁰ C by 20.32 cm slit die of the type shown in Fi'g.t with a 44.5 mm extruder, which was provided with a angtiefe HomogoniSierechnecke low ^. _The base length / diameter ratio of the cylinder of the extrusion press was 24 * 1. The strand was rapidly peeled off at 'a draw ratio of 30Oi1 and brought into contact with a rotating casting roll in contact, the at 82 ⁰ C and at a distance of 6.35 ram from the outlet opening. the nozzle was held. The film produced on this whiteness was wound up and had the following properties: thickness 7.6 ix

Springback from $ 50 stretch, $ 52

1098-21 / 1909

ORIGINAL

Ί7045Α2

The film was then annealed in a stress-free state for 10 minutes at 140 ⁰ C. It was taken out of the warming cabinet and left to cool. It now had the following characteristics:

Springback from $ 50 stretching $ 92

Springback from $ 100 elongation $ 85

EXAMPLE _- I.

The polymer described in Example 5 was as described in Example 6 W _e ise extruded with the difference that the temperature of the melt 199 ⁰ C and the draw ratio 41: 1. After extrusion and rolling, the film had the following properties: thickness 51 / α

Springback from $ 50 stretching $ 40

The film was annealed 1.5 hours in an oven at 140 ⁰ C in the stress-free state. It was taken out of the oven and left to cool. It now had the following properties:

Springback from $ 50 stretching $ 84

Springback from $ 100 elongation $ 77

The following examples illustrate the preparation of films according to the invention according to the blow method illustrated in FIG.

Example_8

The polymers described in Example 1 was carried out at 227 ⁰ C mm by close Ringdüee of 1.02 and extruded 102 mm diameter * The thus-formed hot tube was expanded by blowing with air to 1.4 times, and cooled with βΐηβφ air flow, that from an air ring, which by 4 ^ 3. Nozzle and above the nozzle at which the film was directed. An extrusion press was used for extrusion, the cylinder of which had a length / diameter ratio of 20: 1 and a homogenizing screw with a shallow pitch. The strand was drawn off very quickly at a draw-off ratio of 80: 1 and passed through a series of rollers out that the hose pl ^;: . t le ten and maintained the internal air pressure.

10 3821/1909 "BAD ORIGINAL

- ¹⁵ ■ 170A5A2

After winding at 30.5 m / min, the film had the following Characteristics:

L> J ClVC XC. ti XX

Springback from 50 % elongation 45 %

The film was then heated for 1 hour in the oven at 150 ⁰ C in the stress-free state. After this time it was removed and left to cool. She now had a springback of 88 # from "50 % elongation.

Example 9

The polymer described in Example 1 was extruded in the manner described in Example 8 with the difference that the temperature of the melt was 232 ° C., the tube was expanded 1.8 times, the draw-off ratio was 40: 1 and the draw-off speed was 32 m / min, was = The film produced in this way had the following properties: ⁿ thickness. 25.4 ^ i springback from $ 50> elongation 40 % -

A roll of film made in the manner described above was continuously slit in two places and wound up in the form of two rolls of single-layer film. wobe'i a commercially available cutting and winding device was used. One of these rolls of single-ply film was rotating continuously taut by three Metal rollers drawn and continuously passed over these 'rollers which were held at 147 ° C. The total contact time with the hot rollers took about 2 minutes. After leaving the metal roll, the film was rolled up It now had the following properties:

thickness the end 50 % Elongation 25.4 / kg / cm 9ΑΌ ORIGINAL Springback 85 * 30,900 kg / cm ² g / cm module • 598 tensile strenght 1.41 density 10 % Cloudiness 1 09 8-21 / 1909 • yes * ^; . ■># ■ :: - c

The density of the film, ie "1.4 l g / ciri " is typical for a highly crystalline material ".

Example_10

The polymer described in Example 5, · in the manner described in Eeispiel 8 manner extruded with the difference that the temperature of the melt 177 ⁰ C, the tube was expanded to 2.0 times was the draw ratio. 33: 1, and the Take-off speed was 16.8 m / min. The film obtained had the following properties:

Thickness x 30.5 u

Springback from 50 % elongation 44 %

The film was kept in a tension-free state in a heating cabinet at 120 ^° C. for 20 minutes. After this time, it was removed from the oven and left to cool. She now had an elastic springback of 9 ?. % from 50 % elongation. -

Example 11

The polymer described in Example 5 was extruded in the manner described in Example 8, with the difference that the tube was inflated 2.5 times and the draw-off ratio was 53: 1. The film obtained had the following properties:
Thickness' 19 W.

Springback from 50 % elongation h2%

A roll of film produced in the manner described was continuously slit open at two points individual lanes were made into two rolls of single-layer film with a high-speed, conventional slitting and winding device rolled up. One of these rolls was placed tightly around three rotating metal rolls kept at 119.degree continuously guided over these rollers. The total contact time on the hot rollers was 37 seconds ο that of The film coming from the rollers was wound up, you had

109821/190 9 'SADORlGiNAL

following properties:

thickness

Springback from 50 % elongation Tensile strength in the longitudinal direction Module in the longitudinal direction Elongation at break Density

Cloudiness

The density of the wound film is -0.905 g / cm- typical of a highly crystalline material.

19 al

86 % .
478 kg / cm ² 21.100 kg / W 330 yrs
0.905
8 pounds

This example illustrates the influence of the take-off speed, which results from the speed of the take-off roller, on the elastic behavior. In this example, a polypropylene film was produced in the manner described in the previous examples by extrusion. The temperature of the melt, the width of the nozzle, the speed of the take-off roll and the extrusion speed are given in the following table. The extruded film was taken up on a roll with a diameter of 14 cm and a distance of 38 cm. 1 mm from the nozzle outlet. All foils were annealed at a temperature of 140 ° C. for 10 minutes.

Elastic
Springback

Temperature slot of the melt width of the ⁰ C nozzle

Speed of production of the high-speed draw roller speed, g / 3 min. UpH

52.4
84

84.7
93

204 204 232 204

1.27 mm 7.5 1.27 mm 24 3.81 mm 29 3.81 mm 50

"76.4 189 201 184

The above values clearly show the adverse effect of using a low take-off speed on the elastic springback, ^

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BATH

The above-genannton words of elastic recovery were as follows at 25 ⁰ C and 65 determines # relative humidity: A sample of 15 mm in width was clamped in an Instron Zerrcißmaschinc whose climbed had mm at a distance of 5 * 08 ", the sample was at a rate of 2.54 cm / min - stretched / until 50 # stretch was reached. It was held at this stretch for 1 minute and then _{relaxed at the same speed 3} at which it had been stretched. »The length was noted as soon as the testing machine indicated the relaxed state» The elastic. Springback is then calculated as follows;

Total length after stretching - final distance between

Elastic springback =

D_l £ J £ L ^ -

Length taken after "the strain

χ 100

The other properties were determined according to the following ASTM methods:

Tensile strength: Elongation at break: Module:

Permeability to moisture vapor:

Permeability to O N CO

ASTM D 882, method Λ, Sample width 15

Density:

Turbidity:

ASTM D 882, method A, sample width 15 mm

ASTM D 882, Method A, sample width 2.54 cm

ASTM E 96-62T, Methede B, Ancestors B

ASTM D 1434-63, DOV / Coll-Methodc with the difference that two pieces of film with Intcrchcmical Coating NB 48} C, the thickness was less than 2.5) *> übereinandei · because of the extremely high gas permeability - were geschichtot. '

Determined by Mercury Boron Penetrationj see Textile Research Journal 33, page 21 ff. (196j) by RoGo Quynn «

ASTM D1003, method A according to Figo 2,

10 9 0 /

: Lh, ¹ ·!

SMO ORIGINAL

The above percent crystallinity values are determined by the method described in an article by RG Quynn et al in Journal of Applied Polymer Science, 2, No. 5, pp. 166-173 (1959) *.

The elastic films according to the invention are suitable as elastic pressure-sensitive tapes, elastic decorative straps, elastic device covers, elastic disposable gloves ₃ elastic non-metallic tapes for packaging purposes, as a material for bundling fruits and vegetables, etc.

10 9 821/1909

ORIGINAL

Claims (1)

Ι, polymer film with at least $ 50 crystallinity and one elastic springback of v / c at least $ 70 at 25 C. from $ 50 stretch. 2. Film according to claim 1 made of polypropylene with a crystallinity of at least $ 50 and an elastic springback of $ 85 to $ 95 at 25 ° C from $ 50 elongation. 3 »Polymor film according to claim 1 made of polyoxymethylene with a crystallinity of at least 50 and a $ ^ elastic recovery from 85 to 99 $ at 25 ⁰ C of 50fo elongation. ο polymer folio according to claim ϊ made of polyethylene with a crystallinity of at least $ 50 and an elastic springback of at least $ 70 at 25 ⁰ C from 50 $ elongation. 5 »Film according to claim 1 with an elastic springback of at least $ 70 at -86 ⁰ C from $ 50 elongation, Θ method for producing novel elastic films having a crystallinity in the solid state characterized by at least 50 $ ;, in that a molten polymer at a temperature of the melt point of not more than ctv / a 100 ⁰ C above the Kristallschmclz- * polymeric extrusion press, the film formed at high speed and with a ratio of at least 20: 1 is withdrawn and annealed at a temperature in Ecroich of about 5 ° to 100 ° C below the crystalline melting point of the polymer for a period of at least 5 seconds and as long as that one causes an elastic springback in the film of at least 70 $ at 25 ° C from 5Oro elongation. 7- ancestors according to claim 6, characterized in ₃ that the polymer is in the form of a planarcn ■. Folio with a print ratio of 30; 1 to 1000 % 1 extruded, the film being brought into contact with a cold surface or a St:; o: n cold air at a distance of ctv / a 5 cm from the outlet opening of the extruder, 1098-2 1/1909 OAa ÄAO ORIGINAL 8c method according to claim 6, characterized in that * Iran extruded the polymer in the form of a tube and this by means of compressed air to a larger diameter, its ratio to the diameter of the extruded Foil in the Eercich is between 0.5 and 6.0, expands = Process according to claim 6, characterized in that in the case of polypropylene, iran selects an extrusion temperature of 180 to 2 ^ to ⁰ C and a tempering temperature of 100 to 155 ° C. - 10. The method according to claim 6, characterized in that in the case of polyoxyethylene, an extrusion temperature of 185 to 2 ^ 0 ⁰ C and a Tcmporungstcmpcratur of 110 to 165 ⁰ C selects. 11. The method according to claim 6, characterized in that in the case of polyethylene, an extrusion crapcratur of 175 to -225 ⁰ C and a Tcmperungstcmpcratur of ICO to 15O ⁰ C is selected. 109821/1909 SAO ORIGINAL Blank page