NZ216514A - Polyolefin-polyvinyl alcohol compositions in which the pva is partly or totally bound to the olefin polymer - Google Patents

Description

216514 law M&C FOLIO: 799P51427 WANGDOC: 0312i MODX?Igp POLYOLEFIN AXP PROCEDURE FOR ITS MANUFACTURE, AND ITS USE.

The invention teaches the manufacture of an olefin/viayialcohol segment mixed polymeV by chemically joining polyvinylalcohol (PVA) to polyolefin, for instance by grafting silane to a polyolefin and condensing the silane with the hydroxy groups of polyvinylalcohl or a mixed polymer thereof. In this way. branched polymer molecules are obtained which consist of polyolefin branches (non-polar) and polyvinylalcohol branches (polar). An olefin/vinylalcohol segment mixed polymer possesses properties both of the polyolefin and of polyvinylalcohol. It can be machined by all polyolefin machining methods, and the product is both water-tight (polyolefin) and tight against gas and oil (polyvinylalcohol. It is moreover possible by this procedure to increase the molecular weight of the polymer (to lover the melt index) substantially without risk of cross-1 inking. Since the olefin/vinylalcohol segment polymer is both polar and non-polar at the same time, it can also be used as a so-called emulsifier polymer in plastic alloys consisting of polar as well as 3 j -.0:0-; rc-ssi^isi.zysi 2 1 65 2 non-polar compor.encs, cr an adhesion layer in multi-ply products consisting of polar plies, or metal and non-polar plies.

At present, a.i ethylene/vinylalcohol random mixed '> polymer is Kanufa::u:e<i by hydroxys ir.g an ethylene/vinylacerate random mixed polymer. Hydrolysis (alccholysis) is effected with the aid of alcohol, and Che mixture may be either acid or basic, and the hydrolysis may be carried out in the solid state, in the 1 fj molten state or Ln solution. There is multitude of patents concur nine; this procedure for manufacturing ethylene/vir.ylacohcl random polymers, a summary of them being found in the article "Rectivity of Ethylene Vinyl Acetate Copolymers: A Critical Evaluation of the 15 Comprehensive Patent Literature on the Acetoxy-Hydroxide Transformation of Ethylene Vinyl Acetate Copolymers", R.J. Koopmas. K. van der Linden and E.F. Vansant, Polymer Engineering ar.d Science. July 1982, Vol 22. No. 10. p. 645. All these procedures are based on 20 hydrolysis of the acetate group to give an alcohol group, and there is no mention of any segment mixed polymers. Commercial ethylene/vinylaIcohol random mixed polymers are of two Kinds. Brands containing 20 to 30 rnol-* of vinylalcchol are marketed and their use is 25 mainly for die pressing and for powder coating of steel tubing ("Levasint" by Bayer, and "Mirawithen" by VEB 2165 3 Leuna-WerKe Walter Ulbricht). These brands are made from ethylene/vinylalco.nol random mixed polymer manufactured by a high pressure technique. Also commercially available are brands containing 60 to 80 '■> mol-% vinylaicohol. which are mostly used Cor gas-tight layers in multi ply products (EVAL by Kuraray, and Soarnol by Nippon Gohsei). These brands are manufactured by adding etnylene to the polyvinyl acetate process and hydrolysirtg the product in the sane manner in which polyvinylalcohol (PVA) is made from poiyvinylaceta;e. If there is less than 50 rcoi-% vinylaicohol. the gas-tightness of the product goes down abruptly. When the ethylene/vinylalcohol random mixed polymer contains nore than 60 mol-* vinylaicohol, it forms monoclinic crystals, (the same as PVA). and when there is less than 20 raol-% vinylaicohol, it forms rhobrcic crystals (the same as polyethylene). Between these contents, a mixed crystal structure is dense enough to be applicable as a barrier plastic. it is possible to produce silicones from silanes by polycondensation but in addition, silanes are used n the-plastic industry also as coupling agents, as crosslinking agents and to improve adhesion. The coupling agent idea is based on causing the hydroxyl groups on the surface of a pigment or filler to condense with a silane; the chemical composition of the surface 2 zzi c 5o;o-: 165 is thereby change.! to be such chat it wets the plastic, is admixed with i: or pcssioly reacts chemically with the plastic. The miscibility of filler and plastic, the adhesion between them and the properties both of the !-> molten and solid plastic mixture are improved in this way. It is also possible to cross-link, for instance, plyethylene with a silane in the manner so that unsaturated alkoxysiiane is grafted, with the aid of peroxide or of electron radiation, to the polyethylene i;] chain, whereafter the silane groups are allowed to undergo hydrolysis and to condense with the aid of water and of a condensation catalyst. There is an abundance of patents and patent applications dealing with this technique. Grafting may also be achieved with silyl !'} peroxide (Akzo), cr the unsaturated silane may be added as a comonomec at the polymerizing step already (Mitsubishi), with a silane it is also possible to improve the adhesion e.g. between plastic and metal, or between non-polar plastic and polar plastic, in 20 multi-ply products (>»este).

Polyvinylalcohol (PVA) is mostly used as a dispersing agent in PVC suspension polymerizing, and by regulating the molecular weight of the PVA and its degree of hydrolysis one is enabled to regulate the 25 properties of the PVC. When PVA has a high enough degree of hydrolysis, it is water-soluble. This 2 1 65 water-solubility «i:;d difficult machir.g restrict the use s of PVA in the plastics industry. Ory PVA is interesting in itself because it has excellent barrier properties (gas-tight). With a view to eliminating these rj> drawbacks, the ethylene/vinylalcohcl random mixed polymer (EVAL) has been developed. However, the gas-tightness cf EVAL is dependent on moisture, and it is therefore necessary to protect the EVAL film against air humidity, for instance with a polyethylene film on 10 both sides. Moreover, EVAL does not adhere to plvethyler.e as it is: an adhesion plastic (e.g. Adraer) has to be used between these components in addition. It is. however, a fact that such a five-ply coextrusion design is high exacting and expensive, and EVAL and adhesion plastics are likewise very expensive. 1- EVAL may also be admixed with plastic, and it is then less sensitix'e to moisture. For instance. EVAL is admixed with polyethylene terephthalate (PET), and in this way bottles with better gas-tightness can be produced than by the aid of coextrusion 20 (Eastman-Kodak). EVAL may also be admixed with polyolefins, whereby adequate gas-tightness is obtained (a 30 to 50* addition of EVAL is equivalent to the tightness of polyaraide) and, at the same time, adhesion to polyolefins (no adhesion plastic required) (Neste). ; ■ 65 The above-mentioned mixtures are macro-mixtures . Two phases are produced, and Jo: this reason the products are not transparent.

According to the present invention it has been found, among other things, that a 3ilane which has been grafted to or copolymerized with a polyolefin chain reacts with polyvinylalcohol or with its mixed polymer. This reaction takes place without presence of water and without condensation catalyst (Fig. i). When the reaction takes place in a dry mix, no cross-linking occurs: the polyolefin molecule and the polyvinylalcohol molecule combine with the aid of silane. Mixing and reaction take place at the micro-level (the molecular level), and for this reason there is obtained a transparent, completely new plastic, an olef in/vinylalcohol segment rsixed polyicer (Fig. 2). As polyolefin, there may be used high pressure polyethylene (LOPE), low pressure polyethylene (HOPE, MDPE, LLDPE), polypropylene (PP). poly-1-butylene (PB), poly-4-methyl-l-pentene (TPX) or other polyolefin plastics, rubbers or additives. It is also possible to use mixed polymers, mixtures or homopolymer/mixed polymer mixtures of the polymers mentioned. According to the invention, the silane may be grafted using a peroxide, using an electron radiation or by another expedient, or it may be an unsaturated silane added as a 2 165 comonomer at the polyrr.er iz ing step, such as vinyltcimethoxy-siiane. vinyi tr ethoxysi lane, vinyl-tris(becamethoxyethoxy)silane or gamma-roe thacryloxypropyl tr imethoxysi lar.e . The grafting may '} dlso be carried out. usir:y a i ly Iyer oxide. Act:utdl;iy to the invention, the polyvinylalcohol may be of the brands commonly used in suspension polymerizing PVC, which may be completely or partially (with vinylacetate as comonomer) hydrolysed; etnylene/vinylaIcohol random 1C mixed polymer, or equivalent partly hydrolysed terpolymer; or any other polymer containing between 0.5 and ICO* by weight vinylaicohol.

The olefin/vinylaIcohol segment mixed polymer may be prepared using 1 to 991 by weight polyolefin, 99 to 11. 15 by weight polyvinylsIcohol and 10* by weight silane, calculated on the polyolefin. and the peroxide quantity required for grafting (e.g. 0.01 to 0.5% by weight dicumylperoxide. calculated on the polyolefin) or another radical former. All chemical components that 20 are required may be added in a melt mixer (Banbury mixer. Continuous mixer. Buss Kokneader. etc.) simultaneously in the form of a dry mix, premixed and grafted in solid form or in molten form, or the si lane/peroxide raix and the polyvinylalcohol may be 2b separately added. The main requirement is that addition of the components takes place under such conditions that 3 ZZ z 0 o 0 <10 *• » 4fm 2 1 65 8 the silane first becomes grafted to the polyolefin and only thereafter reacts with polyvinylalcohol. The polyvinylalcohol raay be added after grafting, or the silane grafting may be carried out at a temperature at 5 which the polyvinylalcoho1 is not molten. The reaction mix should be dry so that the silane does not condense. This implies, in the first place, that the polyvinylalcohol has to be dried.

The olef ir./vinylalcohol segment mixed polymer 10 manufactured as taught by the invention may be used as it is in those applications where ethylene/vinylalcohol random mixed polymer is being used. it may be used as a barrier layer in multi-ply products such as film, bottles, and other products. In coextruded products, ^commercial adhesion plastics (e.g. Adner, Plexar, etc.) may be used for adhesion layers, or they may be omitted, depending on the polyvinylalcohol content and on the properties of the other plastic plies. it may also be used in powder coating. The advantage of the 29 olefin/vinylalcohol segment mixed polymer manufactured as taught by the invention is that its manufacture is exceedingly simple and inexpensive, and the raw materials are likewise comparatively inexpensive, compared with commercial EVAL. Furthermore, many kinds of raw materials may be used, for instance polypropylene instead of polyethylene and the degree of hydrolysis of s - - 3 o 2165 1 4 9 the polyvinylalcohol may vary. The vinyl alcohol content nay also be regulated within wide limits, consistent with the intended use of the end product.

Thanks to the segmented structure of the l> olef in/vinylalcohol segment mixed polymer, good adhesion to polyolefins is achieved in coextrusion (no need for adhesion plastic as an intervening layer), and the end products may be hot-seaned with themselves or with polyolefin. It is thus to be understood that the •0 olefin/vinyialcohs1 segment mixed polymer can be used, as it is, as an intervening layer between polyolefin films (three-ply rcextrusion) or together with another polar plastic laysr, for instance polyamide. The olefin/vinylalcohol segment mixed polymer is both I'* gas-tight and wat'Sr vapour-tight, and the gas-tightness is not very highly sensitive to moisture. It may furthermore be diluted with polyolefin or with polyvinylaIcoho1 according to whether higher water vapour tightness or gas tightness is desired. :;0 Furthermore, it may be mixed with other polar or non-polar plastics and. in this way, their barrier properties (gas or water vapour) may be improved or their surface properties may be changed (to become polar or non-polar). The olefin/vinylaicohol segment mixed 2-> polymer manufactured as taught by the invention may also be used as a so-called emulsifier polymer in polymer mixtures and in alloys, in which case it becomes 2 1651 concentrated between immiscible phases and improves the adhesion between them and the usability and machinability of the end product. By using silane in higher proportion to the ?VA content, the rrelt index can be lowered, and when the melt index of the polyolefin is low. very low melt indices (high molecular weights) are reached without cross-1 in'ning in the product. A product is obtained wnich has molten and solid state properties resembling KMW-IIDPK. Such olef in/vinylalcohol segment 1;: mixed polymers with very high molccular weight could be used in applications where high molten strength and good mechanical properties, and durability of the chemicals, are required. Applications of this Kind are: cable sheaths, tubes and pipes, die-blown products, certain high-strength die-cast products, rotation-cast products, sintered products. Multi-component products may also be contemplated because the hydroxyl groups of PVA have good adhesion properties to metals, ceramic substances, fillers and polar plastics, etc.. and whenever required, these adhesion characteristics may be further improved by using coupling agents, such as silane for instance. In these instances, too, the tightness properties of PVA may be utilized. It would in fact be possible, of such an olefin/vinylalccho1 segment mixed polymer with very high molecular weight, to construct a strong and tight petrol tank for an automobile. The high molten strength and the high crystallizing point of PVA could also be 2 :T3 o so;o-: 216514 n utilised in manufacturing foamed products. When PVA crystallises< the foam will no longer shrink. The gas-tightnsss. heat tolerance and strength of a PB tube could be improved by grafting silane to the PB and ■> making it react with PVA, or by coextrudirtg or mixing the P3 with completed olefin/vinylalcohol segment mixed polymer.

By means cf the following, non-restrictive examples shall be illustrated the rnanufacturing of the olefin/vinylalcolhoi segment mixed polymer.

Using a Haaka P.heomix 4000 mixer, the formulations given in Tables 1 and 3 were mixed Cor 7 minutes, using Roller rotors, sp^ed 95 rr.ir. and jacket temperature 200®C. A nitrogen bed was used during mixing, and the pva was dried for 12 hrs at 8c°c, prior to mixing.

T aaIf 1 Tesi t i Pciyolcf in Per ox ice si: ,-ine PVA I 1 LDPE.

MI-7,5; Is -0,913 ! 0.05 phr DC? 0,5 phr VTMO /• PVA-1 i c LDPE.

MI-7,5; 0 -C.913 | 0,05 phr DC? 1.0 phr VTMO z PVA-1 3 LDPE, MI-7,5; 0 -0,918 j 0.05 phr DC? jl.5 phr VTMO z PVA-I ; a LDPE, MI-7.5; r* -0,913 | 0,05 phr DC? i m /* PVA-i i s LDPE, MI-7.5; 0 -0.918 i z PVA- I ! 6 j LDPE.

MI-7,5; p •0,913 : o.os phr DC? U.o phr VTEO «» M PVA-1 ; 7 LDPE, MI-7,5; s -0,918 . 0,05 phr DC? j 1.0 phr VTMO Z PVA-2 ; 8 HOPE, MI-5,0; D -0.955 ; o.o5 phr DC? ! i.o i phr VTMO z PVA—1 j s LDPE, MI-7.5 0 -0.918 j 0,05 1 phr DCP I1,0 phr VTMO z PVA-I s rr; 2 165 1 12 After mixing, trie rr.ixt.ure was rough-ground. and of the ground material sheets wore pressed at 200°C. The following were determined by measurement: laeit m*Jex (MI), density ($). degree of cross-linking, tensile strength, fraction soluble in hot S0:50 water/isopropar.cl mixture, i.e., the degree of grafting of PVA, ar.d the oxygen permeability of a IOC y. sheet (Tables 2 and -1). "able ■ u Te sz Mcl r Densi:y De c i > v » old ' t —■ o': t i: -C-.is: u;: 1 Slcriza-r ion - soiv.b: Oxv^e ;'r<ms 8/10 nsir.j g/ca3 : .r< i::- , T ' «• ( S C rcr ! h? \ a. i - 1 — | * (Uxrr i 3 , 1 en : i ) i 1 1 1.30 j 0,553 3 , / 9, I 10 ,0 J 170 3,? ' 1 33S 2 0.46 !0,955 1 3.3 9 ; io i .0 | 140 2.1 j I 205 3 0.02 j 0,9.10 ; ^ s , 3 :c .5 | 40 : t. * » w 1 137 4 1.53 !0,950 1 3.5 s. /, 9 ,6 j 90 ,2 1 56$ 7.72 :0,545 | n *? i w t - 9.

C 9 .9 i *o 3.5 1 756 6 ; o,o: :0.352 [ •«. o 9, 7 :o .0 | 120 1 .3 1 048 7 0,07 ■0,54 3 j :, 9 9. 9 .2 ; 50 1.1 1 035 s : i 0,01 0,971 i ; 1.8 16, 6 -> » •• iioio 2.7 423 c 9 ; 0,01 ; 0 . 9 7 0 i i 3,2 j 10, 3 i ; 4 1 30 i 2,4 663 ? ion to n. d) In Table 1 are given formulations which contain fairly little polyvinylalcohol. and the quantities and types of components have been systematically varied. Table 2 reveals that by grafting more vinyltriraethoxysilane (VTMO) to LDPE (Tests l, 2 and 3) one achieves more efficient binding (a smaller*soluble 21651 13 part) of Mowiol 4'3S (PVA-l). At the same time. however, the melt index (MI) decreases, owing to increasing molecule size. However, the degree of cross-linking is gather low all the tine, and oxygen transmission, measured by the pressure-free Oxtran ICO method, decreases slightly. By totally omitting the silane (Test 4). under these conditions about half of the PVA-1 can be made to react with LDPE, and the gas transmission is then also clearly higher. On leaving out the dicumyl peroxide (DCP) as well (Test 5), the situation becomes even worse, but in a mechanical LDPS/IO* PVA-1 mixture of this type the oxygen transmission is still lower than that of pure LDPE, which is 2.100 cr.J/r.2d. By using viny 1 tr iethoxys i lar.e (VTEC) (Test 5), PVA-1 can be bound to LDPE slightly nore efficiently than by using vinyltrimetboxysilane (VTMO) (Test 2). The soluble part is less and the oxygen transmission lower, but at the same time the melt index has gone down strongly.

Alkotex 72,5 (PVA-2) (Test 7) produces somewhat lower oxygen transmission results than Mowiol 4/88 (PVA-1) (Test 2) although the degree of hydrolysis (the vinylaicohol content) is somewhat lower. It seems as if pva-2 reacted better with silane (lower soluble part and lower melt index). The density (^) is then, naturally, lower. By using hdpe for basic polymer (Test 8), or higher pva-i contents (Test 9). the oxygen tranmission 2165 14 can be reduced evsn more. 1.0 phc VTMO ar.d 0.05-J phr DC? appears to oe enough for higher ?VA-1 concents as well (smaller soluble parr). Striking are the good strength characteristics of the HOPE/vinylacholol > segment mixed polymer.

Since the oxygen transmission results stated in Table 2 were not low enough with a view to barrier plastic application, the same technique was applied in making mixtures containing 40%. SCt ar.d 6C* ?va-1 Table 3 shows the formulations, and the observation car. be made here that the basic polymer was LDPE and that a fairly small amount c£ DC? and VTMO was used, because the share of LDPE of the total quantity was rather small. For use references, corresponding LDPE/?va-1 1 ^ mixtures without chemical binding were also prepared.

Tcs- Poivclcf ir; Pc-rvxiiii? ?v,\ !io LD?S, Ml=4 .0; •» -0 922 0, 03 phr DCP 1.0 phr VTMO 40 m *9 ?VA-1 | i < i i LDPE.

MI-4 r\. • w , 0 -o. 92: 0, C3 phr oc? 1,0 phr VTMO 50 T PVA-I ! 12 LDPE.

MI-4 .0; P -0. 922 0. 03 phr DC? 1.0 phr VTMO 60 Z PVA- 1 13 LDPE. 0 1 M 31 .2; -0. 922 40 z PVA-1 14 LDPE.

MI-0 .2: 0 -0 922 50 z *3 < > 1 LOPE. 0 1 2T .2; 0 -o.

S22 60 z PVA-l s 3 Je 651 4 Taa ! » r+ / ' 6/ < Dcr.s: l • / 3 r.in; g/CS i <. r ^. i • i M?a 1G 0, 39 f ! 1 i * C5 0 • w 1 5,5 11 c. 24 ft .03 . 1 jn.3 12 0. i i 1 ** • .7 '• 1 " 5 , • - i 13 2 75 V ! 1 i a "i »v J 0 .4 1 :.3 14 r 63 |i ,03 0 . " ! 6,5 6 . 3 7 !, 7 *5 .9 1 13.7 i-.-r.; i :c , . _ ■ Tran «n: «s ior.

Si re rut'.'. ,>.

(Oxtrm 100.-! : 3 2 cn /n d) ; - , ' i 6.0 j C, t I ! I 0 i t i j . i 5 ,C 2 ,4 33,9 ?, 4 ! 55.6 i;J 64 s 2 430 3 651 4 357 In Table 4 is seen the effect oC high PVA-l contents or. che properties of e-hylene/vir.ylalcohol segment mixed polymer (Tests 10-12). With increasing PVA-l contents, the oxygen transmission goes dovn very steeply so that when the PVA-1 content is 60% the oxygen transmission of the ethylene/vinylalcohol segment mixed polymer corresponds to the level of polyamide-5 (PA-6) (11.2 3 2 cm /n d). Simultaneously, the melt index goes down, and density and stiffness increase. In spite of the in high PVA-l content, the soluble part is very snail and the degree of cross-1 inking is low. If, in contrast, the PVA-l is not chemically bound to polyethylene, the properties show no improvement (Tests 13-15). The oxygen transmission is higher than that of polyethylene 2165 16 and increases witr increasing pva-1 concent. Then <il:;o the melt index regains high and the PVA-l is o!moct totally soluble. With the aforementioned mixtures, coextruded strips with ldpe (MI - 4 g/10 rnin. . ^ -3 0.922 g/cm3) were also run. the melt index being 200°C, and it was found chat samples 10-12 adhered fully to polyethylene, while sample 13-15 had no adhesion. The ethylene/vinyl aIcohol segment mixed polymer is a more advantageous barrier plastic, in chis respect, than 'H pa-6. which requires a separate adhesion plastic layer when coextruded with polyethylene.

An ethylene/vinylalcohol segment mixed polymer containing 50t -'VA-1 was also produced in a continuously operating Buss Kci«.neader mixer in che manner that 50t '5 LDPE (MI = 7.5 g/lC pin., 9= C.918 g/cm3) and 50* dried PVA-l were mixed as a dry mix and introduced into the Buss Kofcneader, which had temperature profile 180°C. 210°C, 180°C. After the first zone. 0.03 phr DCP ar.d 1.0 phr VTMO vere injected. The ethylene/vinylaicohol 20 segment mixed polymer thus obtained was granulated and from the granulate a blow film with lOOum thickness was prepared. Kecarding the properties of the film there may be observed that it was homogeneous and transparent, implying that LDPE and PVA had been so 25 efficiently mixed, as a result of grafting, that the 21t>D 14 size of separate phases vas less than the wavelength of light. It aay also be observed that the oxygen transmission of the blown film is considerably less than chat of equivalent pressed sheet (Test 16, 6.7 cm^/m^d).

Three formulations were prepared by admixing ethylene- silane copolyaers with PVA and are presented as tests 17, IS and 19 in Table 5. The aixing was carried out in the saae manner as in tests 10, 11 and 12, with the exception that ^ ethylene-VTM0 copolyaer was used instead of LDPE, DC?, and free VTMO. The ethylene-VTMO copolymer had MI = 0.2g/10 ain, 2 0.917 g/ca , and VTMO content = 1.03.

Testing of the formulations prepared in Example VI was carried out in the saae manner as the testing of the formulations in tests 10, 11 and 12, with the results being reported in Table o.

Proa Table 6, it is seen chat lower oxygen transmission and better mechanical properties are obtained by using an ethyl ene-silane copolymer instead of an ethylene silane graft copolyaer, because a more homogeneous product is obtained. However, che amount of non-reacted PVA is higher. There is also a very rapid decrease in melt index. - 17a - 2]b 5 i 4 ^HLS 5 Test Polvclerin PVA 17 13 t Q MI = 0.2; MI = 0.2; Mi = 0.2; 0.917 £ = 0.917 0.917 1 % VTMD 1 % V3C 1 % VIMD 40 % PVA 50 % PVA 60 % PVA ias*1 TABLE 6 Test Mel- Der.s- Decree of Yield Ul'tisats Elon Sol Oxygen Trans Index ity Crcss- Liai-t "J o gation uble mission. i ■»' —g Strength Part (Cxtran 100) g/10 air. c/aa3 % M?a M?a % % (cra3/a2 d) 17 <0.05 1.12 1.3 .1 22.2 is. ■ 9.1 7 IS <0.05 1.09 1.1 13.2 22.1 9 4.2 1 19 <0.05 1.15 1.2 14.2 23.4 8 8.2 <1 (followed by pag // 2/6 Si4- - 18 "

Claims (14)

WHAT WE CLAIM IS:

1. A modified polyolefin, wherein it contains 1 to 99% polyolefin, mixed olefin polymer or mixtures of polyolefin and 99 to 1* polyvinylalcohol or its mixed polymer and that the polyolefin component and polyvinylalcohol component are partly or totally chemically bound to each other.

2. Modified polyolefin according to claim 1, wherein the polyolefin chain has been copolymerized, grafted or in another way chemically joined to a chemical compound which reacts chemically with polyvinylalcohol.

3. Modified polyolefin according to claim 1 to 2, wherein the chemical compound joined to the polyolefin chain is a silane.

4. Modified polyolefin according to any one of claims 1- 3, wherein the chemical compound joined to the polyolefin chain is an alkoxysilane.

5. Modified polyolefin according to any one of claims 1-£, wherein its melt index (190°C, 2.16 kg) is less than 0.2 g/10 -u i n .

6. Procedure for manufacturing modified polyolefin which contains 1 to 99Z by weight of polyolefin, mixed olefin polymer or mixtures of olefin polymers and 99 to 1% by weight of polyvinylalcohol, wherein to the polyolefin chain a chemical compound is copolymerized, grafted or in another way chemically joined, which compound reacts chemically with polyvinylalcohol to bind said polyvinylalcohol partly or totally to said polyolefin chain. // : --J 3- 14 NOV 1989 2/4 5/4- - 19 -

7. procedure according to claia o, wherein the ael: index (190°C, 2.16 kg) of the modified polyolefin is less than 0.2 g/10 min.

8. Procedure according to claia 6, wherein the reaction is carried out in the absence of water or a condensation catalyst.

9. The use of modified polyolefin according to any one of claias 1-5 as one or several layers in a multi-ply film.

10. The use of modified polyolefin according to any one of claias 1-5 as eaulsifier polyaer in polyaer aixtures and reinforced polyaer combinations composed of polar and non-polar polymers.

11. Procedure for manufacturing modified polyolefin according to any one of claias 6-3 substantially as herein described with reference to any one of the exaaples.

12. Modified polyolefin produced by the procedure of any one of claias 6 to 9 and 11.

13. A aulci-ply fila including at least one layer of a modified polyolefin as claimed in any one of claias 1 to 5 and 12 .

14. A polymer mixture or reinforced polymer combination composed of polar and non-polar polymers including as an eaulsifier polyaer a modified polyolefin as claimed in any one of claias 1 to 5 and 12. NESTE 0Y O r\ - By their Attorneys BALDWIN. SON & CAREY