DD215558A5 - USE OF COPOLYMERS FOR THE MANUFACTURE OF FILMS - Google Patents

Abstract

The present invention relates to the use of copolymers of ethylene and alpha-olefins having at least four carbon atoms which have a density between 0.905 and 0.940 g / cm 3, a flow index between 0.2 and 2 dg / min and an average content of alpha-olefin units between 1 and 8 mole percent, for the preparation of films between 5 and 200 microns thick. The polymers are outstandingly suitable for the production of films. They have the advantage that they allow the same use at a much lower weight and have the same strength as when using the known polymers. The films produced in this way can be used in a variety of ways, in particular for large-capacity bags, rigid films for automatic packaging and films for agriculture.

Description

Berlin, 31.10 * 1903

'Excretion out

AP G 08 ϊ / 241 532/3

(61 110/19)

63 "097/18 ^:

Use of copolymers for the production of films. Field of application of the invention.

The present invention relates to the use of copolymers of ethylene and oC-olefins having at least four carbon atoms, which have a density between 0.905 and 0.940 g / cm, a JPließindex between 0.2 and 2 dg / min and a Durchsehnittagehalt to o (-Olefineinheiten between 1 and 8 mole percent, for the production of films having a thickness between 5 and 200 / um.

Characteristic of the known technical solutions

r "

The literature reveals a large number of examples of copolymers of ethylene and an α-olefin. Thus, the catalysts suitable for polymerizing the ethylene are generally capable of polymerizing the ethylene with an ok- olefin. However, the results of such copolymerization are highly dependent on the catalyst used and, above all, on the quality of the product, of the Nature of the o (O-olefin Copolymers which are best suited for processing into films are those in which the O <-olefin contains at least four carbon atoms For such copolymers, Jj ¹ R-PS 1 604 980 shows, on the one hand, the importance of a narrow one Distribution of molecular masses and, on the other hand, the importance of the distribution of the comonomer between the molecules of the copolymer.

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In view of this latter factor, the cited document teaches that the homogeneous copolymers have better properties for the production of Je'ilmen than heterogeneous copolymers. ^: . ...

However, it is known that a copolymer of ethylene and an OC-olefin, which is intended for processing in certain ways into finished articles, is actually defined only by the simultaneous presence of the following seven features: 1) density, 2) type comonomer, 3) Jj ¹ feed index, 4) molar comonomer content, 5) average molecular mass »6) the polydiapacity number which is the distribution of molecular masses and defined below, and 7) the homogeneity index of comonomer distribution.

"If, in the presence of copolymers having the same or equivalent values for six of the seven preceding features, the fourth characteristic for the seventh feature is found to be entirely different, then for those copolymers having very differentiated capabilities for a particular type of processing, they must become finished articles and finally count on completely different characteristics of the finished objects «

Object of the invention

The object of the invention is to provide heterogeneous copolymers based on ethylene and o (olefins having at least four carbon atoms which are processable into films and possess a set of properties which is at least technically equivalent and preferably better than those of similar or analogous ethylene polymers.

Under the expression "better entirety of the igenigen"

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It should be understood that in the totality of the properties contemplated, not all and at the same time all the properties are improved, but that some of these properties are substantially improved for the benefit of the user of the films, while the other properties are either simply preserved or degraded, without this worsening abolishing the favorable effects of the former. The term "similar or analogous ethylene polymers" should not only be understood as meaning those ethylene copolymers whose suitability for processing into films has been described in the literature, but also and above all the homopolymers dea. Äthylens, the so-called "low-density polyethylenes", as produced by a process under high pressure and in the presence of free radicals as initiators,

presentation; reading the invention

The invention is based on the object, films with improved properties of copolymers)! of ethylene and olefin olefins.

The invention relates to the use of copolymers of ethylene and o (olefins having at least four carbon atoms, which have a density between 0.905 and 0.940 g / cm, a flow index between 0.2 and 2dg / min and a Durchfcjchnittsgehalt of O (-Olefineinheiten between 1 and 8 mole percent, for the preparation of films having a thickness of between 5 and 2OQ / μm, characterized in that laan as copolymers uses those which are obtained by copolymerizing the ethylene and the γ-olefins having at least four carbon atoms.

;. , '·· ^; , ..... :. .. · -. · ⁶ 3 097/18 ··. '

in at least one reactor containing at least one zone having a temperature between 180 and 320 ⁰ O and a pressure between 300 and 2500 bar, by means of a Ziegler Kätalysatörsystems with on the one hand an activator selected from the group consisting of the hydrides and orgahometallischeh compounds of Metals of groups I to III of the periodic table and on the other hand at least one halogen compound of a transition metal, wherein the Ätomverhältnia between the metal of the activator and the transition metal between 1 and 10 and the average residence time of the catalyst system in the polymerization reactor is between 2 and 100 s, on the one hand the feeding the reactor gas stream constant weight of 10 to 80 -.% ethylene and 20 to 90 wt .-% O <-olefin is formed, and on the other hand, the catalyst system has a reactivity with the ethylene, the much r ^ is greater than its reactivity opposite the O (- Olefins are produced.

It has now surprisingly been discovered that it is possible to obtain heterogeneous copolymers of ethylene and Xk olefins having at least four carbon atoms which, in contrast to the teaching of EP-A-1 604 980, are suitable for their processing into films. Own properties ».

In the following description, the term copolymer is used to designate at the same time binary polymers which contain, in addition to ethylene, an e <-olefin and, in addition to ethylene, two ternary polymers containing oC-olefins. Furthermore, the invention ^ü held more than two-ol OXefine also refers in addition to the ethylene-containing polymer *

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First and foremost are copolymers of ethylene and od-olefins having at least four carbon atoms, which copolymers have a density between 0.905 and 0.940 g / cm, a flow index between 0.2 and 2 dg / min and an average content of o (-olefin units are between 1 and 8 mole percent and characterized by Bind, that the distribution of the ^ -glucose units in the copolymer is heterogeneous, said copolymer containing crystalline and amorphous fractions, and that the content of the copolymer ofOi -Olefinjiinhe.iten je varies according to the considered fractions between at least 0.2 and at most 5 times their average salary The copolymers may be further characterized in that their crystalline fractions a single iJchmölzpeak between 110 ⁰ C and 130 C have and 20 to 50 wt.. - % of the total copolymer. '.' yy ^ m?,.

Further, copolymers having an average molecular weight between 15,000 and 60,000 and / or a polydispersity number between 3 and 9 in the case of binary polymers and between 6 and 12 in the case of ternary polymers may be used. In the above definition, in conventional manner in polymer art, the number average molecular mass Mn should be understood as numbers and the polydispersity number as the ratio Mw / Mn of the average molecular mass by weight to the number average molecular mass. On the other hand, the © t-olefins that can be used to form heterogeneous copolymers are, for example, Buten-1, Hexjn-1, Methyl-4-pentene-1 and Okten-1. When two O.sub.10-olefins are present in equilibrium in the copolymer (the case of a terpolymer), their average total content, as described above, is between 1 and 8% by vol

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the ratio of their respective average shares between 0.25 and 4. So z. For example, a terpolymer ethylene / butene-1 / hexene-1 having an average of 95 mole percent of ethylene units "contains on average 1 to 4 mole percent of butene-1 units and 4 to 1 mole percent of hexene-1-units.

The copolymers thus obtained are endowed with remarkable properties and can be made into films having a total of properties which are technically superior to the ethylene polymers known to be processable into films. The most important properties that affect this improvement are the elongation at break and the tear strength. Thus, copolymers according to the invention is generally in the case of films having a thickness of 50 / To an elongation at break between about 600% and 1100%, a tensile strength _t (measured according ÄS'iJM D 1922-67) between about 150 and 900 g, depending on whether in the longitudinal or transverse direction, an industrial ductility of 10 μm or less, depending on the measurement conditions indicated in the examples below, a gloss (measured according to ASTLI D-2457) of 70 % or more and an impact strength (in accordance with the standard IJF T 54 109), which can reach up to 400 g. Ea must be erv / ähnt that, as far as the properties in the longitudinal direction, the thickness of the Meßpröbe must be specified üiuner, since these properties greatly increase with increasing thickness'^''; · ^Λ '''''"λ./' ·. ':''

For the production of the copolymers (AZ AP C 08 F / 241 592/3) no claim is made at this point.

The heterogeneous copolymers are found according to the invention.

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preferred application in the manufacture of films of improved performance and a thickness between 5 and 200 / μm, in particular 20, or below, ie below those of the low density polyethylene films obtained by the radical route. These films are obtained by conventional Jixtrusionsblastechnikenm.it a ^Ä ufblasverhältnis between 1.5 and 4, and have the außergewähnlichen advantage that they allow the same use at a much lower weight and have the same strength as the radical Polyethylene. The films produced in this way have numerous applications, in particular for large-capacity bags, rigid films for automatic packaging and films for agriculture,

Implemented is ρ IeI ^; ; '. ·;

The invention will be explained in more detail below with reference to some examples. The following examples are illustrative and not limiting.

example 1

Ethylene and hexene-1 are copolymerized in a reactor in the form of a cylindrical autoclave operating under a pressure of 1000 bar and equipped internally with a stirrer and metallic diaphragms delimiting three zones of equal volume. Zone 1, operating at one temperature is held by 200? G and supplied with a 3-trom from 49 ^ kg hexene-1 / h and 24 kg of ethylene / h, obtains a catalyst system consisting on the one hand from Dirnethyläthyldiäthylsiloxalan other hand, of a compound of formula TIGL _3, ^ ALOL ₃ , 2 VCl ₃ in such respective amounts,

   · ·:; ··; -8- '31 .10.1933. ·

that the atomic ratio Äl / ΐχ is equal to 3. Zone 2, maintained at ambient temperature T ₂ (at ⁰ C), is fed at a rate of 24 kg / lh and receives the same isocyanate system as described above. Finally, zone 3, at the outlet of which the copolymer-containing fatty acid mixture is evacuated against a separating and recycling device, is maintained at a temperature T _v (at ⁰ C) and receives neither a monomer nor a catalyst, the average weight fraction of hexene-1 in the reactor is therefore 50.5 %. The copolymerization is carried out in the presence of 0.12 mole percent hydrogen. The average residence time of the catalyst system in the reactor is 80 s.

The resulting copolymer is characterized by the following properties:. , ·. ... '· · .- ", - ·; .i

a) Flow index (11) measured according to the iMorm ASTM D .1238-73 and expressed in dg / min. .

b) density f in g / cm ³ , -

c) average molecular mass Mn in numbers, measured by gel permeation chromatography, expressed in thousands,

d) Polydisperia number, determined from Mn and the average molecular weight Mw measured by the same method, by weight,

e) average content of hexene-1 units in the copolymer, expressed in mole percent and based on the percentage of methyl groups for 1000 carbon atoms in the molecule by infrared radiation absorption analysis according to ASTM D 2238-64 T, as described in J ¹ R-PS 1 604 930, measured,

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f) index of homogeneity of the distribution of the Cotoonoiaer »determined by oil polymer fractionation stat And expressed dusch the multiple and the fraction c # ii of the average content _t between which ddt? The amount of witches varies from one to four.

g) Melting point: the crystalline hcaciton of the oopolymer, expressed in ⁰ Q and determined by ultra-elastic. thermal analysis. , '.

The values of these properties are summarized in Table 1 below with the hosts of ΐρ and ΐ-s. ,

Example 2 . ...: ... ';..''.:..'..: ·. ";

One copolymerizes ethylene and witches--! tuiter Aüchter keeping a pressure of 10ö0 bar in the same reactor before and under the same conditions except for the following exceptions. Zone 1 is fed with a stream of 61 kg hexene-1 / h and 25 kg ethylene / h. Zone 2 receives a flow of 25 kg ethylene / h. The average weight loss of hexene-1 in the reactor is thus 55 %. The copolymerization is carried out in the absence of hydrogen. The catalytic efficiency R, expressed in kg of copolymer per 10 "x ³ g of transition metal, and the properties of the resulting copolymer are shown in the following Table X.

Ethylene and hexene-1 are copolymerized while maintaining a pressure of 600 bar in the same reactor as before and under the same conditions except the following.

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the exceptions. Zones 1 and 2 are each fed with a stream of 27.5 kg athylene / h and 28.5 kg of hexene-1 / h. Accordingly, the average weight fraction of hexene-1 in the reactor is 50.9 %. The copolymerization is carried out in the presence of 0.06 mol% of hydrogen peroxide. The catalytic efficiency and the .Eigenschaften of the copolymer obtained are shown in Table I below.

Table X

example ¹ Z ^X 3 'Μ / Μη- ^R c , 7 1 0 IF IH , 6 3 ,, 4 0 , 929 ; _r,. · 225 270 3 7.5 5, , 5 6 0 , 36 , 9 1 , 6 0 , 920 " ^: '2 ^: 210 255 4 3,4 7, , 0 1 0 0 , 22 2 2 »5 0 , 934 3 220 245 6 8.2 6 1 20 Table I (Continuation) P ° C example  .Mxi, Hexene-1 126 ' ^/:. 1'.'. , 21 1 125 '·' .2. "^:;: 46 4 M 127 $ ". · ^: ' 18 2 Example 4

Copolymerizing ethylene and octene-1 while maintaining a pressure of 1000 bar ^ n the same reactor as above and under the same conditions as in Example 3 except for the following exceptions _e Zones 1 and 2 are each with 24 kg of ethylene einem'Strom / h and 29 kg octene-1 / h fed · The average weight fraction of octene-1 in the reactor is thus 35 ..% ·. ^SS ie copolymerization

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is carried out in the absence of hydrogen, wherein the temperatures Tp and 1 'of Zones 2 and 3 are 200 ⁰ G and 250 ⁰ G, respectively. The average residence time of the catalyst system in the reactor is. 80th's. The copolymer obtained with a catalytic efficiency R. of 7 kg per 10 ^{J of} grams atomic length has the following properties:

Ι.ί ¹ . = 0.25 , 1 mole. Mn * 57 000 g / cnr Octene-1 -R * 1 C = O, 933 Mw / Mn a 3.3 F = 127 ⁰ G Example 5

Ethylene and butene-1 are copolymerized in a heat exchanger in the form of a cylindrical autoclave which operates under a pressure of 900 bar and is equipped in its interior with a stirrer and three-zone delimiting metallic diaphragms. ! The maintained at a temperature of 210 ⁰ C first zone "has a volume which is twice as large as that of each of the following two zones, and with a ^ trom of 200 kg / h of a 36 wt _o -% butene-1 and 64 wt .-% ethylene existing mixture and receives a catalyst system which contains on the one hand Dirnethyläthyldiäthylsiloxalan and on the other hand a compound of formula TiGl ^, 4 AlGl-, VC1_ in such respective amounts that the atomic ratio Al / Ti is equal to 3. Die auf a .Temperature .. '240 ⁰ G genaltehe zone 2 is at a current of 55 kg / h of the same mixture as above obtained is fed and the same catalyst system. the zone 3, finally, at the

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Exit the copolymer-containing reaction mixture is evacuated against a separation and Rückführhreinlehr.hung, is maintained at a temperature of 280 ⁰ C and receives neither a monomer nor a catalyst. The average Yerweii'zeit the catalyst system in, reactor is 43 s. , · '. '' · · ^: ·, '..';., \ .. ";' , ''. ^: ''.

The catalytic efficiency and the properties of the copolymer obtained are evident _; the following Table II ... '^;'; / :. ''' * ' .'...' ^:

Example 6 .... ''''"..:'. ^!

In the absence of hydrogen, ethylene, uten-1 and hexcn-1 'are terpolymerized in the reactor described in Example 1, operating under a pressure of 1000 bar. The zone 1, which is maintained at a temperature of 180 ⁰ G, is fed with a stream of 13 kg hexene-1 / h, 14 kg of ethylene / h and .6 kg of butene-1 / h and receives a catalyst system, consisting on the one hand from Djunethyläthyldiäthylailoxalan and on the other hand from a compound of formula TiCl ₃ , -i AlCl ₃ , G MgGl ₂ , 0.5 HiCl ₂ in such respective amounts that the atomic ratio Al / Ti is equal to 3. The maintained at a temperature of 225 ⁰ C zone is fed with a, ^ trom of 14 kg of ethylene / h and 6 kg ßuten _r 1 / h and receives the same catalyst system as described above. The zone 3, finally, at whose outputs _a ng the Reaktionsmischung'gegen the terpolymer containing a separating and Fdbk Üiire is evacuated inr ichtung 'is maintained at a temperature of 245 ⁰ C and receives neither a Monome'r still a catalyst. The average proportions by weight in the reactor thus amount to 53 % of ethylene,

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24 % hexene-1 and 23 % butene-1. The average residence time of the catalyst in the reactor is 85 S _0. The catalytic efficiency and the properties of the resulting terpolymer are given in Table I below. , '...', '. ''

Example 7

In the presence of 0.15% of hydrogen, ethylene, butene-1 and hexane-1 are terpolymerized in the yeast actuator described in Example 1 and operating at a pressure of 800 bar. The held on a tempering of 180 ⁰ C Zone 1 is fed with a stream of 27 »1 kg hexene-1 / h, 18.4 kg of ethylene / h and 1.6 Leg Butene-1 / h and receives that in Example 5 Catalyst system described, Zones 2 and 3 ", which are maintained at temperatures of 220 ⁰ C and 260 ⁰ C, be;; each fed with a 3-stream of 18.4 kg ethylene / h and 1.6 kg butene-1 / h. The average residence time of the catalyst system in the reactor is 100 s. The catalytic efficiency and the properties of the resulting terpolymer are shown in Table II below.

Example 8 ". '. .

In AnwesenJrieJtt of 0.1% hydrogen to ethylene and butene-1 are copolymerized in the reactor described in Example 1, which mixtures with a constant formed gas stream from 35 üew .-% ethylene and 65 -.% Butene-1 is fed. The zones 1, 2 and 3 operate at temperatures of 200 ⁰ G, 210 ⁰ O baw. 235 ° G »and the catalyst system used is that described in Example 1. The average residence time of the catalyst system in the reactor is 45 s. The cat

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lytic efficiency, and the properties of the resulting copolymer are shown in Table H ₀ below

Table II 6 2 IF 0 Ö1'9. 1 Hexene-1 Mn ' IH Μ, Αΐη I ' ¹ example 4 , 5 0.8 0 915 43 0,5 - 3.6 122 , '' 5. ' 4 , 9 0.5 .: 0 933 0.9 15 0,3 - 10.5 121 6 '. _; ;. 6 3 0.6 0 908 1.3 21.5 0,2 - 7.6 128 .7 " 0.8 (Iortsetzung) '·'. - 25 0,5 - 5.4 117 8th Buteh- Table II example • 2.2 • 3.0 .6 ^; :   i, 8 . 7; - _? 3.2 • 2.0 8th 2.6 Examples 0.4; 6.0 until 14

The copolymers of Examples 1 to 3, 4, 5, and 7 are processed by supercrystallization under the following conditions to give a surface of 50 μm:

- Resin temperature: 230 ⁰ G. ;>'

-. Rotation speed of the iixtruder screw: 80 rpm

- ^A ufblasverhältnis: 2.0

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The properties measured on these pillows are:

a) The breaking elongation AR (in%) in the longitudinal direction L and in the transverse direction ¹ Ji, determined according to ASTM D 882-67.

b) The tensile strength RB (in g) in the longitudinal direction L and in the transverse direction T, determined according to ASTM D 1922-67.

The results of these measurements are listed in Table III, it being understood that Examples 9 to 11 relate to the copolymers of Examples 1 to 3 and Examples 12 to 14 to the copolymers of Examples 4, 5 and 7.

Table III 9 10 11 12 13 14 example 750 635 635 630 910 · 760 Ar L 860 805 610 660 1060 850 190 680 16O 150 300 200 AD L 775 900 430 500 640 440 T

Moreover, the thickness of Example 10 has an impact strength (measured according to Jüorni HF T 54 109) of 300 g.

In addition, all of the copolymers examined above have an industrial drawability determined by that of 5 μm by that film thickness which permits continuous production by extrusion blowing for 2 hours without disturbances. ·

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^: . · ''' ^/ . ... ' . / ' :' ·. "'', 63 097/18 ''''

Example 15 ... '..'''

' *''·'. , , , ·

The copolymer of Example 8 is made into a film of thickness / 50 μm by xixtrusion blowing / under the above conditions. Measure the following own shade on this film: · -

.- Impact resistance: 400 g.

- Tear strength in the longitudinal direction: 600 g .- Tear strength in the transverse direction: 800 g.

Example 16 'V''; , /. ,

The films obtained according to Examples 10, 13 and 14 are subjected to measurement of the following optical properties: gloss (according to ASTM D-2457) and haze (according to ' Λ3ΤΜ D-1003) ο These "percent printed" i properties have the in Table IV fourth.

table IV example 13 example 14 Jiilm Example TO : - 80 7 13 Shine. cloudiness 95 10.5

Claims (1)

-17- 31.10. 63 097/18 .u'rfindunKsanspruch Use of copolymers of ethylene and O (olefins having at least four carbon atoms which have a density between 0.905 and 0.940 g / cm 2 V a .Fließindex 0.2 to 2 dg / min and a purehschnittsgehalt of e (-Olefineinheiten between 1 and S mole percent, for the preparation of films having a thickness between 5 and 200 / um, characterized in that the copolymers used are those obtained by copolymerizing the Äthylens and O ^ olefins having at least four carbon atoms in at least one reactor which at least a zone with a temperature between 180 and 320 ⁰ C and a Pruck between 300 and 2500 bar contains, by means of a Ziegler Katälysätörsystems on the one hand with an activator selected from the group consisting of the hydrides and organometallic compounds of metals of groups I to III of the Periodic Table and on the other hand at least one halogen compound of a transition metal, wherein the atomic ratio between the M each of the activator and the transition metal is between: 1 and 10 and the average residence time of the catalyst system in the polymerization reactor is between 2 and 100 s., wherein on the one hand the gas stream feeding the reactor is constant from 10 to 80% by weight of ethylene and 20 to 90% by weight On the other hand, the catalyst system has a reactivity toward the ethylene which is much higher than the reactivity to the OC olefins.