Patent EA-004069-B1 (EA)
Title: Multilayer thermostatic structure
Inventor: KARSTEN PETRUS J A
IPC: B32B7/022
Filed: 2000-03-29
Abstract: 1. A thermoplastic polymer based multilayer structure, substantially devoid of vinyl chloride polymers and low molecular mass plasticizers, comprising at least 3 layers: a first layer (A) comprising at least 60 % by weight of at least one polyolefin with controllable crystallinity, defined as comprising at least 90 % ethylene, propylene or butene and having a softening temperature of less than 121 degree C, the thickness of the first layer being 20 % of the total thickness of the structure, whereby the first layer has a modulus of elasticity of less than 350 MPa; a second layer (B)disposed between the first (A) and third (C) layer, comprising at least 40 % by weight of at least one polyolefin with a controllable crystallinity, whereby the second layer has an overall softening temperature that is lower than 121 degree C; a third layer (C) comprising at least 50 % by weight of at least one polyolefin with controllable crystallinity, the thickness of the third layer being 5 - 30 % of the total thickness of the structure, and the third layer having a modulus of elasticity that is lower than that of the first layer, wherein under polyolefin with a controllable crystallinity is understood polymer, comprising at least 90 % ethylene, propylene or butene. 2. The structure according to claim 1, in which polyolefin with controllable crystallinity is a copolymer. 3. The structure according to one of claims 1 to 2, in which polyolefin with controllable crystallinity is a copolymer, comprising at least 90 % ethylene, propylene or butene, and at least 10% of one or several other copolymers, selected from the group consisting of (C5-C10)- alkenes, and also carboxylic acids and carboxylic acid esters. 4. The structure according to one of claims 1 to 3, in which the first layer has an overall softening temperature above 121 degree C. 5. The structure according to one of claims 1 to 4, in which the third layer has an overall softening temperature above 121 degree C. 6. The structure according to claim 5, in which the third layer has an overall softening temperature that is lower than 121 degree C. 7. The structure according to one of claims 1 to 6, in which polymer or polymers, forming the first layer, are selected exclusively from the group consisting of polyolefins with controllable crystallinity or and polyolefins with low crystallinity rate or amorphous polyolefins. 8. The structure according to one of claims 1 to 7, comprising one or several outer layers based on a thermoplastic polymer or thermoplastic polymers from the first layer and/or the third layer opposite to the second layer. 9. The structure according to one of claims 1 to 8, in which the surface layer from the first layer side comprises copolymer of cyclic olefin and/or propylene homopolymer mixed with styrene ethylene/ butylene styrene blockcopolymers. 10. The structure according to claim 8, in which the surface layer from the first layer side comprises copolymer of cyclic olefin and/or propylene homopolymer mixed with styrene ethylene/ butylene styrene blockcopolymers and polyolefins with low crystallinity rate. 11. The structure according to one of claims 1 to 10, in which the turbidity and total thickness ratio is such that the structure turbidity is less than 10% with the thickness 200mum. 12. A thermoplastic polymer based multilayer structure, substantially devoid of vinyl chloride polymers and low molecular mass plasticizers, comprising at least 3 layers, the total thickness is from 100 to 400 mum, wherein said structure simultaneously has: a modulus of elasticity of less than 350 MPa; a quantity of compounds extracted with boiling hexane is less than 3; turbidity/thickness ratio is less than 6% with the thickness 200mum. 13. A process for preparing a structure according to claim 1, in which different layers are produced by a joint extrusion and subsequently subjected to: - at least one drawing step by at least 100%at a temperature from the maximum polyolefins crystallization temperature with controllable crystallinity rate (Tc) to Tf+15 degree C, wherein Tf is the minimum softening temperature thereof; - at least one relaxation step to constant dimensions during at least 10 sec carried out in the same temperature interval; then -a a step of quenching to a temperature, which is less the maximum crystallization temperature Tc. 14. An article based on the structure according to one of claims 1 to 8 or prepared according to claim 13 in the form of a tube, film or a container. 15. An article prepared by welding of a structure according to claim 6 with the same or other structure having the outer layer of the same composition as the third layer. 16. A sealed container obtained using the article according to claim 15, having at least one permanent seam and separated into at least two compartments by easily separable welded seam. 17. Use a container according to claim 16 for separate storing and/or sterilization of liquids and mixing thereof by rupturing of easily separable welded seam. 18. A method for manufacturing a container according to claim 16, characterized in that easily separable welded seam is realized at a temperature which is less by at least 5 degree C of the permanent welded seam. 19. The method according to claim 18, characterized in that the permanent welded seam is realized at a temperature from 125 to 160 degree C, and easily separable welded seam is realized at a temperature from 95 to 140 degree C.