Process for preparing polyalkenamers for packaging applications

Abstract

The present invention relates to a process for producing cycloalkenamer-containing compositions and to such cycloalkenamer-containing compositions. The invention further relates to the use of these cycloalkenamer-containing compositions in the field of packaging materials, especially for food and drink.

Claims

1. A process for producing a polyalkenamer-containing composition, comprising the steps of: a) converting at least one cycloalkene by ring-opening metathetic polymerization, in the presence of a chain transfer agent, to obtain a polyalkenamer-containing product-mixture, b) converting the product-mixture into solid form, c) granulating or pulverizing the product-mixture in solid form to particles prior to step d), and d) working up the product-mixture to remove the at least one cycloalkene monomer and/or an oligomer of the at least one cycloalkene to obtain the polyalkenamer-containing composition, wherein step d) is effected by extraction in a solvent mixture comprising at least one solvent 1 and at least one solvent 2, where the solubility parameter of the solvents 1 is not more than 20.07 MPa.sup.1/2 and the solubility parameter of the solvents 2 is at least 20.27 MPa.sup.1/2.

2. The process according to claim 1, wherein the at least one solvent 1 is present in relation to the at least one solvent 2 in a mass ratio of 95:5 to 5:95.

3. The process according to claim 1, wherein the at least one cycloalkene is at least one member selected from the group consisting of cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclododecene, cycloocta-1,5-diene, 1,5-dimethylcycloocta-1,5-diene, cyclodecadiene, norbornadiene, cyclododeca-1,5,9-triene, trimethylcyclododeca-1,5,9-triene, norbornene (bicyclo[2.2.1]hept-2-ene), 5-(3-cyclohexenyl)-2-norbornene, 5-ethyl-2-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, dicyclopentadiene, and a mixture thereof.

4. The process according to claim 1, wherein the at least one solvent 1 is at least one member selected from the group consisting of hexane, heptane, diamyl ether, diethyl ether, butyl butyrate, ethyl amyl ketone, butyl acetate, methyl isobutyl ketone, methyl amyl ketone, amyl acetate, ethyl n-butyrate, carbon tetrachloride, diethyl carbonate, propyl acetate, diethyl ketone, dimethyl ether, toluene, ethyl acetate, tetrahydrofuran, benzene, tetrachloroethylene, chloroform, methyl ethyl ketone, chlorobenzene, dichloromethane, chloromethane, 1,1,2,2-tetrachloroethane, ethylene dichloride, and a mixture thereof.

5. The process according to claim 1, wherein the at least one solvent 2 is at least one member selected from the group consisting of acetone, 1,2-dichlorobenzene, carbon disulphide, 1,4-dioxane, cresol, aniline, pyridine, N,N-dimethylacetamide, cyclohexanol, cyclohexanone, butyl alcohol, 2-butyl alcohol, acetonitrile, dimethyl sulphoxide, N,N-dimethylformamide, furfuryl alcohol, propylene glycol, 1,2-propylene carbonate, ethanol, methanol, propanol, isopropanol, a butanol, ethylene glycol, ethylene carbonate, glycerol, water, and a mixture thereof.

6. The process according to claim 1, wherein the extraction is conducted within a temperature range from 20 C. up to the boiling range of the solvent mixture.

7. The process according to claim 1, wherein the solvent mixture is a single phase.

8. The process according to claim 1, wherein the solvent removing of step b) is performed by vacuum degassing.

9. The process according to claim 1, wherein the conversion of the at least one cycloalkene is conducted in the presence of a catalyst.

10. The process according to claim 1, wherein the solvent mixture comprises at least one stabilizer.

11. The process according to claim 1, wherein the at least one solvent 1 is at least one member selected from the group consisting of hexane, heptane, toluene, tetrahydrofuran, chloroform, methyl ethyl ketone, dichloromethane, ethyl acetate, and a mixture thereof.

12. The process according to claim 1, wherein the at least one solvent 2 is at least one member selected from the group consisting of acetone, isopropanol, acetonitrile, ethanol, methanol, propanol, a butanol, water, and a mixture thereof.

13. The process according to claim 1, wherein the conversion of the at least one cycloalkene is conducted in the presence of a catalyst comprising at least one transition metal halide and an organometallic compound or comprising at least one transition metal-carbene complex.

14. The process according to claim 1, wherein the conversion of the at least one cycloalkene is effected in the presence of an acyclic alkene as chain transfer agent having one or more non-conjugated double bonds, or a cyclic compound having a double bond in their side chain.

15. A polyalkenamer-containing composition containing at least 95% by weight of polyalkenamer, wherein less than 20,000 ppm of a monomer of a cycloalkane and/or an oligomer of a cycloalkene are present, based on the polyalkenamer-containing composition.

16. The polyalkenamer-containing composition according to claim 15, wherein the polyalkenamer is at least one member selected from the group consisting of cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclododecene, cycloocta-1,5-diene, 1,5-dimethylcycloocta-1,5-diene, cyclodecadiene, norbornadiene, cyclododeca-1,5,9-triene, trimethylcyclododeca-1,5,9-triene, norbomene (bicyclo[2.2.1]hept-2-ene), 5-(3-cyclohexenyl)-2-norbornene, 5-ethyl-2-norbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, dicyclopentadiene, and a mixture thereof.

17. A process of making a packaging material, the method comprising: shaping the polyalkenamer-containing composition according to claim 15 into a packaging material.

18. The process according to claim 17, further comprising: encasing food or drink in the packaging material.

Description

EXAMPLES

(1) Polymers

(2) Polymer 1: Vestenamer 8020 (Polyoctenamer) of Evonik, Germany was used as the polyalkenamer-containing product mixture.

(3) Polymer 2: Polymer 2 was produced from polymer 1 by a re-granulation process. Polymer 1 was fed into a twin screw extruder Werner & Pfleiderer ZSK30 via the main hopper. The barrel temperature was 125 C. A screw speed of 250 rpm was applied and the throughput of the polymer was chosen to be 6 kg/h. The effective melt temperature at the die was measured with a thermometer to be 186 C. After leaving the front plate of the extruder at the die the melt strand was cooled in a water bath and after that in air. Then the polymer strand was pelletized with a pelletizer (cutter). The cutter was operated at a strand speed of 57 m/min. The re-granulation process was conducted until an amount of 100 kg of polymer 2 was obtained.

(4) Determination of Molecular Weight

(5) The molecular weights of the polymers were determined by gel permeation chromatography (method: cf. description).

(6) TABLE-US-00001 VESTENAMER 8020 Mn in Mw in Mp in (polyoctenamer) g/mol g/mol g/mol Polydispersity Polymer 1 8700 156100 114000 18.0 Polymer 2 9100 164300 116900 18.1 Mn = number average molecular weight Mw = weight average molecular weight Mp = peak molecular weight
Trans Content of Double Bonds

(7) The trans-content of double bonds of both polymers was determined by .sup.1H NMR in deuterochloroform (CDCl.sub.3). The trans-content was 80% for polymer 1 and polymer 2.

(8) Average Particle Weight

(9) Polymer 1: The average weight of the particles is 54.0 g/1000.

(10) Polymer 2: The average weight of the particles is 2.1 g/1000.

(11) (method: cf. description)

(12) Solvents

(13) n-Hexane: Merck, n-Hexane for liquid chromatography LiChrosolve, >=98.0% GC (solvent 1) Toluene: Sigma-Aldrich, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., >=99.7% GC (solvent 1) Acetone: Sigma-Aldrich, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., >=99.5% GC (solvent 2) Isopropyl alcohol: Sigma-Aldrich, >=99.7% FCC, FG (solvent 2)

(14) The solvents used in examples are miscible.

(15) Extraction Procedure

(16) Equipment

(17) Electric shaking apparatus Memmert WNB45/SV2945: 250 mL Erlenmeyer flask with glass stopper and fixing clip.

(18) Extraction

(19) A sample of 10 g of polymer 1 or polymer 2 was transferred into a 250 mL Erlenmeyer flask. After that 180 mL of extraction medium was introduced. The extraction medium consisted of a volume/volume mixture of one solvent 1 and one solvent 2. The exact compositions of these mixtures are given in table 1. These solvent mixtures were homogeneous, single-phase mixtures (no phase separation was visible). In the comparative examples only extraction media were used which consisted of one solvent. As indicated in table 1 in some cases Irganox 1076 was introduced into the extraction medium (2 mg was added into 180 mL of extraction medium by using 100 L of a 20 mg/mL solution of Irganox 1076 in the extraction medium). The flasks were closed with the stopper. Thereafter the flasks were transferred into a water bath with a temperature of 20 C. or 40 C., respectively. While being in the water bath the flasks were shaken by means of an electric shaking apparatus for four hours at a frequency of 105/min. After four hours the solvent was removed and a sample of 4 g of polymer was taken. The remaining amount of 6 g was put back into the Erlenmeyer flask and another 180 mL of extraction medium was added. Then the extraction procedure was conducted as described before. After another four hours of shaking time (in total now 24 hours) the extraction medium was removed and the polymer material was collected. The material was then dried at room temperature under a gentle nitrogen flow. After that the samples were kept at ambient conditions under air for 24 hours. The samples related to a total extraction time of 24 hours were then subjected to the measurement of cyclooctene content and the content of di-, tri- and tetramers of cyclooctene (cf. description).

(20) TABLE-US-00002 TABLE 1 results of extraction - amounts of oligomers solvent dimer/ trimer/ tetramer/ total/ # polymer solvent 1 solvent 2 mixture stabilizer temp./ C. mg/kg mg/kg mg/kg mg/kg 1* 1 3520 9576 6487 19583 2* 2 1629 9969 6604 20202 3* 2 acetone yes 40 <100 185 1829 2114 4* 2 acetone yes 20 523 2580 3147 6249 5* 1 acetone yes 40 841 2758 3240 6838 6* 2 Isoprop. yes 40 329 1696 2701 4726 7 2 hexane acetone 20:80 yes 40 <100 178 1091 1369 8 2 toluene acetone 20:80 yes 40 <100 <150 1541 1791 9 2 hexane acetone 10:90 yes 40 <100 <150 1467 1717 10 1 hexane acetone 20:80 yes 40 <100 240 1257 1596 11 2 hexane acetone 20:80 yes 20 <100 195 1730 2025 12 2 hexane acetone 40:60 yes 20 <100 <150 1566 1816 13 2 hexane acetone 20:80 no 40 <100 <150 857 1107 14 2 hexane isoprop. 20:80 yes 40 <100 <150 1575 1825 15 2 toluene isoprop. 20:80 yes 40 <100 240 1400 1740 *non-inventive isoprop. = isopropyl alcohol

(21) Samples #1 and #2 contain 15 mg/kg or 11 mg/kg of monomer cyclooctene, respectively. Cyclooctene in samples #3-#15 is below the levels detectable by method of analysis (below 0.5 mg/kg).

(22) Without any extraction, polymer 1 comprises 19.583 mg/kg and polymer 2 comprises 20.202 mg/kg of oligomers. In case of an extraction with acetone or isopropyl alcohol (#3-#6) the total amount of oligomers is much higher than in case of #7-#15 performing with solvent mixtures.

(23) TABLE-US-00003 TABLE 2 comparison of examples in view of same conditions total oligomers total amount of oligomers and (comparative percentage amount of reduction group of tests examples) (examples according to the invention) polymer 2, 2114 (#3) 1369 (#7) 1791 (#8) 1717 (#9) 1107 (#13) acetone, 40 C. 35.2% 15.3% 18.8% 47.6% polymer 2, 6249 (#4) 2025 (#11) 1816 (#12) acetone, 20 C. 67.6% 70.9% polymer 1, 6838 (#5) 1596 (#10) acetone, 40 C. 76.7% polymer 2, 4726 (#6) 1825 (#14) 1740 (#15) isoprop., 40 C. 61.4% 63.2%

(24) By performing the inventive extraction method the oligomers which cause odor are reduced in an amount of 15.3% to 76.7%. In other words by adding a solvent with a solubility parameter of not more than 20.05 (J/cm.sup.3).sup.1/2 the undesirable oligomers can be removed in higher amounts within the same time period (namely eight hours). Consequently, the extraction of oligomers by using the inventive method is faster and more effective than extractions of the art.