AMORPHOUS OLEFIN CO/TER-POLYMERS

Abstract: Amorphous and impact resistant co/ter-polymer made from olefins and aryl-substituted cyclic monomers by polymerizing using a catalyst, wherein the substituent is a phenyl- or indanyl-group and the catalyst is a metallocene-catalyst. Preferably said aryl-substituted cyclic monomer is phenyl-norbornene (5-phenyl-bicyclo-2,2,1-hept-2-ene) or indanyl-norbornene (1,4-methano-1,4,4a,9a-tetrahydrofluorene).

Description: Amorphous olefin co/ter-polymers The invention is related to the manufacturing of amorphous olefin co/ter-polymers. The invention especially concerns the improvement of the softness, flexibility and impact properties of amorphous co/ter-polymers by using substituted cyclic co-monomers. Cycloolefin - copolymers ( COC ) are manufactured commercially using metathesis ring- opening polymerization providing thermoplastic COC - polymers with high glass transition temperatures ( Tg ) and good optical properties (used in compact discs etc.). Furthermore COC - polymers are manufactured commercially by co-polymerizing ethylene and cycloolefins using vanadium type Ziegler-Natta-catalysts, also providing good optical properties and heat resistance, but rather bad impact properties. Also by using metallocene catalysts ethylene-cycloolefin-copolymers with high Tg have been made. Based on the patent examples, however, these technologies are focusing on using norbornene or tetracyclododecene as comonomer. Typical for both these co-monomers is the bad impact properties of their COC - polymers. This is due to the fact that the forces between the polymer chains are very weak ( van der Waal's forces ), because the polymer chains are fully saturated hydrocarbons ( paraffinic ). Furthermore there is a very low degree of entanglement of these polymer chains due to their stiffness. The idea with this invention is that the cyclic comonomer is substituted with a chemical group which increases the forces between the polymer chains as well as decreases the rotation of the cyclic comonomer around the polymer chain ( stiffens the chain ). When the substituent is a phenyl-group or any other kind of aromatic group the forces between the polymer chains increase due to the interaction of - electrons. In this respect a non- condensed aromatic group like the phenyl-group can move more freely and find another phenyl-group in a neighbouring chain, in which case the improvement of the impact properties is greater than if the aromatic group is condensed or otherwise linked to the cycloolefin via several bonds ( like the indanyl-group ). The phenyl-group also decreases the rotation around the polymer chain but not as much as when the substituent is linked to the cycloolefin via several bonds ( tetracyclododecene, indanyl-norbornene etc. ). Less rotation around the polymer chain increases the Tg more efficiently. By using metallocene catalysts and methylaluminoxane ( MAO ) as cocatalyst one can make amorphous ethylene-co/ter-polymers which have both high heat resistance ( high glass transition temperature, Tg ) and good impact properties. When ethylene is co- polymerized with phenyl-norbornene, indanyl-norbornene or any other aryl-substituted norbornene stiff er polymer chains ( higher Tg:s ) are obtained as when incorporating the same amount of norbornene. In addition one obtains a softer, more flexible and more impact resistant product. The greatest disadvantage with the present cyclo-olefin- coplymers ( COC ) is their bad impact resistance. Due to the fact that the substituted nprbornenes mentioned above have a more stiffening effect on the polymer chains than norbornene substantially lower incorporations are needed which is a great advantage from a production as well as economical point of view. Furthermore phenyl-norbornene ( 5 - phenyl - bicyclo - 2,2,1 - hept - 2 - ene ) is made from styrene and indanyl-norbornene ( 1,4 - methano - l,4,4a,9a - tetrahydrofluorene ) from indene using dicyclopentadiene as the other component in a Diels-Alder-reaction. These raw-materials are readily available liquids which are easy to transport and store and also the corresponding cyclic monomers are liquids and can therefore be easily purified and fed to the polymerization process. Norbornene on the other hand is made from ethylene and dicyclopentadiene which requires that the monomer reactor is connected to an ethylene pipe-line or to an ethylene cold-storage and the reactor needs to stand higher pressures. Draw-backs of norbornene are also its semisolid state and very intense and bad odor. Using for instance Molecular Modelling the stiffening effects of different substituted cyclic monomers on the polymer chain have been noticed. Due to these effects the heat resistance and impact resistance of ethylene-phenylnorbornene and ethylene-indanyl- norbornene are higher and the hardness lower compared to corresponding ethylene- norbornene-copolymers ( with the same molar ratios ). The amount of aryl-substituted cyclic monomer in the polymer can vary within a large range. Therefore its concentration can be within 1 - 90 mol % but in most practical cases within 20 - 75 mol %. According to the invention the ansa-metallocene catalysts are suitable catalysts even if also Ziegler-Natta catalysts and other suitable polymerization catalysts can be considered. One can for instance use ethylene bis ( indenyl ) zirconium dichloride or dimethylsilyl bis ( indenyl ) zirconium dichloride. As cocatalyst an alkylaluminoxane like methylaluminoxane ( MAO ) can be used. The amount of cocatalyst can vary so that the Al / Zr - ratio is in the range of 10 - 10,000. The polymerization can be done in a conventional way, for instance in a suitable solvent at 10 - 90 °C for 0.2 - 20 h. In the following examples and tables the invention is described more in detail. They are, however, only presented in order to clarify the invention and should not limit the scope of the invention. Example 1 The synthesis of COC - polymers The appropriate amount of norbornene and/or substituted norbomenes was dissolved in toluene and diluted to 200 ml after which molecular sieves were added in order to absorb water. The next day the solution was poured to a 0.5 1 Buchi reactor which was thermostated and equipped with a stirrer. Then the reactor was purged with nitrogen after which the chosen amount of methylaluminoxane ( MAO ) was added and the reactor was purged with ethylene and ethylene was added until the solution was samrated at the chosen pressure. The ethylene pressure and temperature were controlled automatically and it was assumed that ethylene dissolved in toluene according to Henry 's law. When the toluene solution was saturated with ethylene and the ethylene pressure and temperature were constant the metallocene catalyst was pumped to the reactor as a diluted toluene solution. Now the polymerization started and the ethylene consumed in the polymerization was automatically replaced so that the ethylene pressure stayed constant. When the polymerization was stopped by closing the ethylene feed and venting the reactor its contents was poured into ethanol and some hydrochloric acid was added. After filtration the polymer was washed with acetone, filtrated again and dried. Example 2 The heat resistance ( Tg ) and Shore hardness of COC Ethylene and cyclic monomers ( PhN = Phenyl-Norbomene, 5-Phenyl-bicyclo-2,2,l-hept- 2-ene : InN = Indanyl-Norbornene, l,4-Methano-l,4,4a,9a-tetrahydrofluorene : N = Norbomene, Bicyclo-2,2,l-hept-2-ene ) were polymerized as explained in Example 1. The toluene solution was 200 ml, the ethylene pressure 3 ata, the temperature 30 °C, the catalyst 2 mg ethylene bis ( indenyl ) zirconium dichloride ( catalyst A ) and the cocatalyst MAO ( Al/Zr = 3000 ). The polymerization time was 1 h. In Table 1 are presented the properties of polymers made in this way. Table 1 The heat resistance and hardness of COC Run Comonomer Yield Tg Shore- hardness 1 30 mol-% (5,9 g) FN 14.0 g < 0 °C 65°A/°D 2 50 mol-% (13,8 g) FN 11,9 g 113 °C 45°A 3 70 mol-% (32,0 g) FN 86,0 g Oily - oligomer 4 30 mol-% (6,3 g) IN 12,5 g 104 °C 60°D 5 50 mol-% (7,6 g) N 12,9 g 32 °C 67°D 6 7,6 g N + 5,9 g FN 16,4 g 43 °C 45°D From Table 1 it can be seen that by using aryl-substituted norbomenes as comonomer the heat resistance ( Tg ) is better than when using the same amount of norbomene (5 ). By reducing the amount of phenyl-norbomene in the reaction mixture from 50 mol % ( 2 ) to 30 mol % ( 1 ) the Shore hardness increased. However, when increasing the amount of phenyl-norbomene to 70 mol % ( 3 ) the the concentration of comonomer was so high that an oil-like oligomer was obtained. Indanyl-norbornene ( 4 ) is stiff er than phenyl- norbomene ( 1 ) and therefore stiffens the polymer chain more efficiently ( higher Tg and Shore-hardness ). The Shore-hardness for the ethylene-norbomene-phenylnorbornene- terpolymer ( 6 ) was lower than for the ethylene-norbomene-copolymer ( 5 ) even if the heat resistance was higher. Also the yield of this terpolymer was rather high. Example 3 ( references ) Ethylene-norbomene-copolymers used as reference-materials. Ethylene and norbomene were copolymerized in the same way as in Example 1 but the toluene solution was 250 ml and different polymerization conditions were used. The amount of MAO was 3000 Al/Zr in all runs except ran 15 where it was 6000 Al/Zr. Table 2 The heat resistance and hardness of ethylene-norbomene-copolymers Run Comonomer P T Cat. Time Yield Tg Shore- ata °C mg h g °C hardness 7 50 mol-% 2 30 2 12,5 39 69 n D 8 50 mol-% 2 50 2 3,6 < 0 66°D 9 50 mol-% 4 30 2 16,8 < 0 68°D 10 50 mol-% 4 50 2 24,6 < 0 65°D 11 70 mol-% 4 30 2 22,3 90 71°D 12 70 mol-% 4 50 2 23,5 85 77°D 13 70 mol-% 4 30 2 0,5 15,3 90 74°D 14 70 mol-% 4 30 4 0,5 17,3 101 75"D 15 70 mol- 4 30 2 0,5 13,1 93 72°D 16 50 g 4 30 4 0,5 11 ,0 124 77°D 17 70 g 4 30 4 0,5 15,5 142 82°D 18 90 g 4 30 0,5 3,5 155 84°D From Table 2 it can seen that all ethylene-norbomene-copolymers were very hard and when their Tg:s were above room temperature their compression moulded plaques were also so brittle that they broke when folded. Only by adding very big amounts of norbomene can Tg:s over 100 °C be obtained. When using 50 mol % norbomene or less the heat resistance was very bad. When the Tg increased also the Shore hardness increased. Example 4 Ethylene and phenyl-norbomene were copolymerized in the same way as in Example 1 and the characterization was done in the same way as in Example 2, but the polymerization parameters were changed one at a time. Table 3 The influence of different polymerization parameters on the heat resistance and Shore hardness of ethylene-phenylnorbornene-copolymers Run Comonomer "New" Yield Tg Shore- g conditions g °C hardness 19 10 30°C, 0,5 h 14,5 51 49°A/13°D 20 10 50°C, 0,5 h 14,8 29 70°A/25°D 21 10 30°C, 0,5 h 7,7 < 0 40°A/9°D 1 mg cat. A 22 20 30°C, 0,5 H 11,0 40 62°A 23 20 30°C, 1 h 26,5 110 37°D 24 10 30°C, 0,5 h, 0,2 42 59°A/19°D 2 mg cat. B From Table 3 it can be seen that when using 10 g ( 42 mol % ) phenyl-norbomene (19) the yield was of the same order of magnitude as when using 5.9 g ( 1, Table 1 ) even if the polymerization time was only 0.5 h. Also the Tg was higher. By increasing the polymerization temperature to 50 °C ( 20 ) the yield remained on the same level but the Tg decreased and the hardness increased. This copolymer was, however, much softer than the ethylene-norbomene-copolymers. When the amount of catalyst was decreased to 1 mg ( 21 ) the yield decreased accordingly and the heat rsistance and hardness decreased. In other words very low catalyst- and cocatalyst-concentrations can be used when copolymerizing ethylene and phenyl-norbomene and also less comonomer is needed compared to the copolymerization of ethylene and norbomene. These are very great advantages from a production and economical point of view. When the amount of phenyl-norbomene was 20 g ( 59 mol % ) ( 22 ) the yield and Tg were lower but the polymer was harder than when using 10 g ( 19 ). This amount of phenyl-norbomene in relation to ethylene is clearly too high under these conditions. When polymerizing for 1 h ( 23 ) under the same conditions the yield was, however, very high and the Tg was higher. In this case a lot of ethylene was consumed at the end of the polymerization and the temperature increased. In other words, the concentration of the polymer solution was so high ( too much catalyst and cocatalyst under these conditions ) that the reaction accelerated. One should, however, notice that by using 20 g phenyl- norbomene one can obtain Tg:s which are on the same level as when using 50 g norbomene ( 16 ). This heat resistant ethylene-phenylnorbornene-copolymer ( 23 ) was , however, also soft and impact resistant. Also by using 2 mg dimethylsilyl bis ( indenyl ) zirconium dichloride ( catalyst B ) as catalyst an ethylene-phenylnorbornene-copolymer ( 24 ) was obtained, which had about the same Tg and hardness as when using 2 mg ethylene bis ( indenyl ) zirconium dichloride ( catalyst A ), but the yield was considerably lower. Example 5 In this example the impact resistance of copolymers made from ethylene and aryl- substituted norbomenes were compared with those made from ethylene and norbornene. In the previous examples the elasticity of COC was described by the Shore-hardness but in order to describe this property more clearly also their Charpy impact properties are presented. Table 4 The impact resistance of different COC:s Run Comonomer Yield Tg Charpy, kJ/m 2 g g °C Notched/Unnotched 2 13,8 FN 11,9 113 25/No break 4 6,3 IN 12,5 104 5/No break 16 50,0 N 11,0 124 -/ 1,3 kJ/m 2 From Table 4 it can be seen that by using aryl-substimted norbomenes instead of norbomene a corresponding heat resistance ( Tg ) can be obtained with much lower / amounts of comonomer and the impact resistance is significantly better. COC:s containing aromatic groups can therefore be heat resistant as well as impact resistant and they can be made using rather small amounts of comonomer which decreases the variable costs as well as the investment costs of the production.

Claims: Claims: 1. An amorphous and impact resistant co/ter-polymer made from olefins and aryl- substituted cyclic monomers by polymerizing using a catalyst, wherein the substituent is a phenyl- or indanyl-group and the catalyst is a metallocene-catalyst. 2. A co/ter-polymer according to claim 1, wherein said aryl-substimted cyclic monomer is phenyl-norbomene ( 5-phenyl-bicyclo-2,2,l-hept-2-ene ). 3. A co/ter-polymer according to claim 1, wherein said aryl-substimted cyclic monomer is indanyl-norbornene ( l,4-methano-l,4,4a,9a-tetrahydrofluorene ). 4. A co/ter-polymer according to claims 1-3, wherein the content of aryl-substimted cyclic monomer is 1 - 90 mol-%. 5. A co/ter-polymer according to claims 1-4, wherein the metallocene catalyst is an ansa- metallocene catalyst and the cocatalyst is methylaluminoxane ( MAO ). 6. A co/ter-polymer according to claims 1-5, wherein the metallocene catalyst is ethylene bis ( indenyl ) zirconium dichloride or dimethylsilyl bis ( indenyl ) zirconium dichloride. 7. A co/ter-polymer according to claims 1-6, wherein the glass transition temperature is more than 25°C. 8. A co/ter-polymer according to claims 1-7, wherein the Shore-hardness is less than 90°A. 9. A co/ter-polymer according to claims 1-8, wherein the olefin is ethylene or propylene. 10. A ter-polymer according to claims 1-9, wherein there is a third monomer in addition to the olefin and the aryl-substimted cyclic monomer. 11. A process for making co-/ter-polymers with improved impact properties from olefins and aryl-substimted cyclic monomers, wherein the comonomer is a phenyl- or indanyl-substituted cyclic monomer and the catalyst is a metallocene catalyst. 12. A process according to claim 11, wherein the catalyst is of the ansa-metallocene type and the cocatalyst is methylaluminoxane. 13. A process according to claims 11 or 12, wherein the cyclic monomer is phenyl- norbomene ( 5-phenyl-bicyclo-2,2,l-hept-2-ene ) or indanyl-norbomene ( 1 ,4-methano- l,9a,4,4a-tetrahydrofluorene ) and the concentration of substimted monomer 1 - 90 mol- %. / 14. Process according to claims 11-13, wherein the catalyst is ethylene bis ( indenyl ) zirconium dichloride or dimethylsilyl bis ( indenyl ) zirconium dichloride.

Inventors: AHJOPALO LISBETH, BERGSTROEM CHRISTER, HASE TAPIO, PAAVOLA SARI, PIETILAE LARS-OLOF, RUOTOISTENMAEKI JUHANA, SEPPAELAE JUKKA, AHJOPALO, LISBETH, BERGSTROEM, CHRISTER, HASE, TAPIO, PAAVOLA, SARI, PIETILAE, LARS-OLOF, RUOTOISTENMAEKI, JUHANA, SEPPAELAE, JUKKA
Applicants: AHJOPALO LISBETH, BERGSTROEM CHRISTER, HASE TAPIO, OPTATECH CORP, PAAVOLA SARI, PIETILAE LARS OLOF, RUOTOISTENMAEKI JUHANA, SEPPAELAE JUKKA, AHJOPALO, LISBETH, BERGSTROEM, CHRISTER, HASE, TAPIO, OPTATECH CORPORATION, PAAVOLA, SARI, PIETILAE, LARS-OLOF, RUOTOISTENMAEKI, JUHANA, SEPPAELAE, JUKKA
Application year: 1996
Main classification: C08F210
IPC codes: C08F4, C08F210, C08F232