WO1994021726A2 - Single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure - Google Patents
Single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure Download PDFInfo
- Publication number
- WO1994021726A2 WO1994021726A2 PCT/EP1994/000852 EP9400852W WO9421726A2 WO 1994021726 A2 WO1994021726 A2 WO 1994021726A2 EP 9400852 W EP9400852 W EP 9400852W WO 9421726 A2 WO9421726 A2 WO 9421726A2
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- WIPO (PCT)
- Prior art keywords
- ethylene
- procedure according
- film
- copolymer
- olefin
- Prior art date
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- 229920006257 Heat-shrinkable film Polymers 0.000 title claims abstract description 10
- 239000002356 single layer Substances 0.000 title claims abstract description 10
- 229920000092 linear low density polyethylene Polymers 0.000 title claims abstract description 7
- 239000004707 linear low-density polyethylene Substances 0.000 title claims abstract description 7
- 238000000034 method Methods 0.000 title claims description 35
- 238000004519 manufacturing process Methods 0.000 title description 6
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000005977 Ethylene Substances 0.000 claims abstract description 16
- 239000004711 α-olefin Substances 0.000 claims abstract description 15
- 239000000956 alloy Substances 0.000 claims abstract description 14
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 14
- 229920005674 ethylene-propylene random copolymer Polymers 0.000 claims abstract description 12
- 229920005684 linear copolymer Polymers 0.000 claims abstract description 11
- 238000002425 crystallisation Methods 0.000 claims abstract description 8
- 230000008025 crystallization Effects 0.000 claims abstract description 8
- 239000003112 inhibitor Substances 0.000 claims abstract description 8
- 238000001125 extrusion Methods 0.000 claims abstract description 6
- 238000001816 cooling Methods 0.000 claims description 12
- 229920005989 resin Polymers 0.000 claims description 8
- 239000011347 resin Substances 0.000 claims description 8
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 claims description 5
- YBYIRNPNPLQARY-UHFFFAOYSA-N 1H-indene Chemical compound C1=CC=C2CC=CC2=C1 YBYIRNPNPLQARY-UHFFFAOYSA-N 0.000 claims description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 4
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 239000011159 matrix material Substances 0.000 claims description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 3
- 229920001384 propylene homopolymer Polymers 0.000 claims description 3
- PMJHHCWVYXUKFD-SNAWJCMRSA-N (E)-1,3-pentadiene Chemical group C\C=C\C=C PMJHHCWVYXUKFD-SNAWJCMRSA-N 0.000 claims description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 2
- BKOOMYPCSUNDGP-UHFFFAOYSA-N 2-methylbut-2-ene Chemical compound CC=C(C)C BKOOMYPCSUNDGP-UHFFFAOYSA-N 0.000 claims description 2
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 2
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 2
- 229920006271 aliphatic hydrocarbon resin Polymers 0.000 claims description 2
- 229920006272 aromatic hydrocarbon resin Polymers 0.000 claims description 2
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 claims description 2
- 238000006555 catalytic reaction Methods 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- RYPKRALMXUUNKS-UHFFFAOYSA-N hex-2-ene Chemical compound CCCC=CC RYPKRALMXUUNKS-UHFFFAOYSA-N 0.000 claims description 2
- PMJHHCWVYXUKFD-UHFFFAOYSA-N piperylene Natural products CC=CC=C PMJHHCWVYXUKFD-UHFFFAOYSA-N 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- HJWLCRVIBGQPNF-UHFFFAOYSA-N prop-2-enylbenzene Chemical compound C=CCC1=CC=CC=C1 HJWLCRVIBGQPNF-UHFFFAOYSA-N 0.000 claims description 2
- 150000003505 terpenes Chemical class 0.000 claims description 2
- 235000007586 terpenes Nutrition 0.000 claims description 2
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 2
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 claims 1
- 238000003786 synthesis reaction Methods 0.000 claims 1
- 239000000047 product Substances 0.000 description 20
- -1 polyethylene Polymers 0.000 description 14
- 239000004698 Polyethylene Substances 0.000 description 11
- 229920000573 polyethylene Polymers 0.000 description 11
- 229920001577 copolymer Polymers 0.000 description 8
- 229920000642 polymer Polymers 0.000 description 7
- 239000000654 additive Substances 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 239000013032 Hydrocarbon resin Substances 0.000 description 5
- 238000007664 blowing Methods 0.000 description 5
- 229920006270 hydrocarbon resin Polymers 0.000 description 5
- 238000010096 film blowing Methods 0.000 description 4
- 238000004806 packaging method and process Methods 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical compound CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 2
- 239000004594 Masterbatch (MB) Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229920000089 Cyclic olefin copolymer Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 229920001198 elastomeric copolymer Polymers 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229920001179 medium density polyethylene Polymers 0.000 description 1
- 239000004701 medium-density polyethylene Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 229920002959 polymer blend Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/28—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of blown tubular films, e.g. by inflation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
- C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
- C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
- B29K2023/04—Polymers of ethylene
- B29K2023/06—PE, i.e. polyethylene
- B29K2023/0608—PE, i.e. polyethylene characterised by its density
- B29K2023/0625—LLDPE, i.e. linear low density polyethylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/0088—Blends of polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0037—Other properties
- B29K2995/0049—Heat shrinkable
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
- C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
- C08J2323/04—Homopolymers or copolymers of ethene
- C08J2323/08—Copolymers of ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
Definitions
- linear medium and low density polyethylene for the production of single-layer biaxially oriented heat-shrinkable film has been known for a long time.
- Linear polyethylene has found extensive application in the packaging sector as heat-shrinkable films, which require a good transparency and gloss, high mechanical resistance combined with high shrinking values.
- linear polyethylene - compared with branched polyethylene - exhibits the following characteristics:
- a single-layer heat- shrinkable film comprising linear low density polyethylene can be obtained by a procedure comprising the steps of : a) preparing a mixture consisting of : - an ethylene/ ⁇ -olefin linear copolymer,
- the present invention contemplates a single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure.
- the primary component of said film is an ethylene/ ⁇ -olefin linear copolymer with 4-8# by wt. ⁇ -olefin.
- Said copolymer is added with 10 to 0% by wt. heterophasic polymers alloy composed of a matrix consisting of propylene homopolymer and a disperse phase consisting of a synthetic elastomer, e.g. ethylene/propylene.
- the ethylene/ ⁇ -olefin linear copolymer may be alternatively or also added with 10 to 50 by wt . ethylene-propylene random copolymer .
- a non-alternative additive may be an oligomer of the so-called crystallinity inhibitors group .
- linear ethylene/ ⁇ -olefin copolymer means a copolymer of ethylene and from 4 to 8 by wt . butene or octene or ⁇ -methyl pentene , having linear
- the preferred cc— olefin is octene.
- copolymer density ranges from 0.900 to 0.935 g/c ⁇ and melt index from 0.7 to 4.0.
- polymeric alloy also known as “catalloy” -
- 2o means a product obtained by catalytic reaction composed of a matrix consisting of propylene homopolymer and a disperse phase (copolymer) .
- the disperse phase of said alloys may consist of ⁇ — olefins of the C2-C or C -C / 1 type . Density is 0.88 to 0.90 g/ci- and melt index is 0.7 to 4.
- ethylene-propylene random copolymer means a synthetic product obtained from ethylene and propylene, the latter being the major component, e.g. 10% ethylene and 90% propylene.
- aliphatic and aromatic hydrocarbon resins aliphatic and aromatic copolymers , such as piperylene , methylbutene , vinyltoluene , indene , ⁇ -methylstyrene, polycyclodiene , etc. , hydrogenated CQ resins , styrene, ⁇ -methylstyrene, isobutene, pinene and rosin resins , and terpene resins .
- the ethylene/ ⁇ -olefin linear copolymer can be hardly oriented by the twin-bubble procedure.
- a further possibility of mixture adjustment consists in the addition of crystallization inhibitory oligomers .
- the present invention introduces some innovations in the traditional twin-bubble procedure, which allow an accurate product control during the process critical phases.
- Extrusion is carried out by single-screw extruders, 28-32 diameters long.
- the melted mixture leaves the extruder die in a tubular form at a temperature of l8 ⁇ ° C to 205°C.
- the tubular film diameter is a function of the desired max. stretching ratio of the final film.
- the tubular film leaving the extruder is sized and cooled by a new method in respect of the conventional twin-bubble extrusion technique.
- the tubular film, which is still hot is sized by passing between an outer ring, wherefrom a liquid coolant at 15 ° C-25 ° C flows continuously, and a mould, internal to the tubular film, which is also cooled by a liquid coolant at 15°C-25°C.
- the max. temperature variation along the tubular film circumference is 1 ° C. A more uniform thickness and a greater homogeneity of the extruded material are thus secured.
- the tubular film temperature drops to 2 ⁇ °-32°C in few seconds, preferably within 4 to 9 sec.
- the water leaving the outer ring adheres, as a liquid film, to the tubular film outer surface and flows to the chamber underneath.
- the cold tubular film is then fed to an IR-ray or hot-air oven where it is heated to a temperature close to softening. Once heated to the desired temperature, the tubular film is inflated with compressed air and expanded in the transversal direction.
- the tubular film inflation is carried out by controlling the operating temperature within ⁇ 1 C.
- the tubular film is stretched in the longitudinal direction by causing the pull-roll upstream of the oven and the final pull-roll to operate at a different speed.
- the film Once the film has undergone double hot stretching, it is rapidly cooled to maintain the inner orientation of molecules, resulting from transversal inflation and longitudinal stretching.
- the stretched film is cooled to 25°C-35°C by blowing air at 5 ° C to 1 ° C within 15 to 30 sec.
- the film obtained according to the claimed procedure is 10 to 40 ⁇ thick and exhibits improved characteristics over the product obtained by the known technique.
- the film of the invention having thickness between 12 and 25 um exhibits:
- the procedure under the invention gives a film with characteristics tailored to the various uses. Thanks to the above characteristics, the film as per the present invention is suitable for the packaging sector in general and in particular for the applications requiring a good film shrinkage and adhesion to the packed product as well as a good mechanical and heat seal resistance.
- the claimed film is particularly fit for the packaging of vegetables, boxes, food also of irregular shape, books and magazines, multiple packed products, etc.
- a single-layer film, 15 ⁇ thick, consisting of the following raw materials was produced.
- the basic polymer used was linear polyethylene containing 8 % by wt. octene (melt index 1 and sp. gr. 0.923), in particular Clear Flex FG 308 produced by Enichem Polimeri. Said polymer was added with 20% by wt. propylene-ethylene polymeric alloy (melt index 0.8 and density 0.89 g/cm ⁇ ) , in particular the elastomeric copolymer Hi Fax 7023 XEP produced by HIM0NT.
- the crystallinity inhibitor was a completely saturated hydrogenated hydrocarbon resin , Eastotac 140 produced by Eastman Kodak , having molecular weight of 900 approx . and Brookfield viscosity of 1000 approx .
- Said resin after dispersion in low density polyethylene ( 50% ) to give the masterbatch (Prisma AD WAX 90237 produced by Frilvam) was added to the basic polymer mixture in a 5% amount equivalent to 2.5% pure resin.
- antiblock and sliding additives were used to improve film handling in production and application phases .
- 0.5% micronized silicon dioxide was used as antiblock agent (equivalent to 1% masterbatch of type AB 6004 produced by Constab) .
- the operating conditions were as follows: - temperature of the melted material leaving the die: l8l°C - cooling water: 19 ° C ⁇ 1
- Table 1 shows the characteristics of the film obtained and, for the purpose of comparison, the characteristics of commercial product CLYSAR LLP (DuPont).
- the film obtained according to Example 1 showed an improved tear strength in respect of CLYSAR LLP.
- Example 2 The procedure of Example 1 was repeated with the difference that the mixture of raw materials was further added with ethylene-propylene random copolymer (melt index 1.8), in particular with 10% Moplen EP2 S 3 F (HIM0NT) .
- the product obtained showed higher elastic modulus and improved optical characteristics. It was also stiffer than that as per
- Example 1 and, therefore, more adequate for use in automatic fast packaging machines. Also handling conditions improved, the bubble stability being higher .
- the melted material temperature ranged from 185°C to 188°C and the tubular film blowing temperature was 126°C.
- Table 1 shows the characteristics of the film obtained. Compared with the product as per Example 1, the film had a higher heat seal resistance and improved optical properties.
- Example 1 The procedure of Example 1 was repeated with the difference that the mixture was further added with ethylene-propylene random copolymer (melt index 4), in particular with 10% Moplen
- the product obtained exhibited improved heat sealing characteristics (lower sealing temperature in respect of the product as per Example 2, which means shorter sealing times and wider sealing range) . Also seal resistance was improved.
- Example 2 Furthermore, like in Example 2, the temperature range was wider than in Example 1, and bubble stability was the same.
- Example 1 The procedure of Example 1 was repeated with the difference that the polymeric alloy was completely removed and the quantity of ethylene-propylene random copolymer (melt index 4) , in particular Moplen SYL 7008 XCP ( HIMONT ) was increased
- the product obtained had excellent heat seal characteristics. On handling, bubble stability and thickness distribution were excellent.
- Table 1 shows the characteristics of the film obtained.
- Example 1 The procedure of Example 1 was repeated with the difference that the hydrocarbon resin was added in a 1 . 5% amount in respect of the basic copolymer.
- the product obtained was a medium-stiff and medium-shrinkable film.
- the operating conditions were similar to those of Example 1: temperature of melted product leaving the die: 183°C tubular film blowing temperature: 123 C
- Table 1 shows the characteristics of the film obtained. Compared with the previous products, this film exhibited good mechanical properties and excellent tear strength.
- Example 1 The procedure of Example 1 was repeated with the difference that the basic copolymer was linear polyethylene (melt index 1.1; sp. gr. 0.920) containing 8% octene, with more uniform distribution (Dowlex NG 06 E produced by Dow Chemical).
- the basic copolymer was linear polyethylene (melt index 1.1; sp. gr. 0.920) containing 8% octene, with more uniform distribution (Dowlex NG 06 E produced by Dow Chemical).
- Example 2 The procedure of Example 2 was repeated with the difference that the basic resin was added with 7% propylene-ethylene polymeric alloy and with 2% random copolymer.
- Example 1 The procedure of Example 1 was repeated without addition of polymeric alloy.
- the bubble could not be maintained at stable and uniform conditions and frequent bursts occurred. No improvement even by considerably varying all operating conditions. Significant and measurable samples could not be obtained.
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- Engineering & Computer Science (AREA)
- Polymers & Plastics (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Laminated Bodies (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Connection Or Junction Boxes (AREA)
Abstract
Single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene obtained by extrusion and twin-bubble biaxial orientation of a mixture of ethylene/α-olefin linear copolymer, a polymeric alloy and/or an ethylene-propylene random copolymer and optionally a crystallization inhibitor.
Description
SINGLE-LAYER BIAXIALLY ORIENTED HEAT-SHRINKABLE FILM COMPRISING
LINEAR LOW DENSITY POLYETHYLENE AND RELEVANT PRODUCTION
PROCEDURE
Prior art
The use of linear medium and low density polyethylene for the production of single-layer biaxially oriented heat-shrinkable film has been known for a long time.
Linear polyethylene has found extensive application in the packaging sector as heat-shrinkable films, which require a good transparency and gloss, high mechanical resistance combined with high shrinking values.
Generally, however, there are various reasons for the biaxial orientation of linear polyethylene being harder than that of normal branched polyethylene. First of all, orientation is hindered by the polymer structure being free from long branched chains and having a higher crystallinity percentage.
Furthermore, the density being the same, linear polyethylene - compared with branched polyethylene - exhibits the following characteristics:
- a higher melting point by 10°C to 20°C approx.
- just a few very short side chains
- narrow molecular weight distribution. Collectively, the above features hinder orientation. However, the experimentation on linear polyethylene was a
source for the development of particular types of such polyethylene suitable for orientation.
For example, USP 4,497,920 (Du Pont) claims the production of a heat-shrinkable film consisting of an ethylene/α-olefin linear copolymer having two distinct crystalline melting points below
128°C.
The existence of two melting areas according to the above patent allows an easy biaxial orientation of the film, which can be processed between the two melting points.
As known, polymers like linear polyethylene which tend to crystallize on cooling generally exhibit one crystalline melting point by calorimetric analysis.
It is, therefore, very hard to determine the temperature or a temperature range at which the extruded tubular film is sufficiently ductile for blowing (with biaxial orientation) and at the same time sufficiently tough to resist blowing pressure. It follows that the twin-bubble orientation of crystallizable polymers (linear polyethylene, polypropylene and polyolefins in general) is extremely critical, in particular in the case of a single-layer film.
Summary
It has surprisingly been found that a single-layer heat- shrinkable film comprising linear low density polyethylene can be obtained by a procedure comprising the steps of : a) preparing a mixture consisting of :
- an ethylene/α-olefin linear copolymer,
- a polymeric alloy and/or an ethylene-propylene random copolymer, and optionally
- a crystallization inhibitor; b) extruding, in the melted state, the mixture obtained under a); c) rapid cooling of the tubular film leaving the extrusion die to a temperature of 28°C to 32 C and subsequent heating to a temperature close to softening; d) biaxially orienting the film by the twin-bubble technique; e) rapid cooling of the biaxially oriented film to 25 C-35°C. The claimed procedure allows an easy and precise control of the operating parameters as well as the obtainment of films with improved mechanical, optical and heat seal resistance properties.
Detailed description of the invention
The present invention contemplates a single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure. The primary component of said film is an ethylene/α-olefin linear copolymer with 4-8# by wt. α-olefin.
Said copolymer is added with 10 to 0% by wt. heterophasic polymers alloy composed of a matrix consisting of propylene homopolymer and a disperse phase consisting of a synthetic elastomer, e.g. ethylene/propylene.
The ethylene/α-olefin linear copolymer may be alternatively or also added with 10 to 50 by wt . ethylene-propylene random copolymer . A non-alternative additive may be an oligomer of the so-called crystallinity inhibitors group .
5 The addition, if any , of said oligomer in a by wt . % amount ranging from 1 to 20 in respect of the basic copolymer depends on the type of primary mixture ( more or less rich in crystallizable polymeric components ) , on the procedure and on the operating conditions ( more or less favouring crys tals
,Q formation) , and to the desired final characteristics of the product.
In particular , the expression " linear ethylene/α-olefin copolymer" means a copolymer of ethylene and from 4 to 8 by wt . butene or octene or α-methyl pentene , having linear
, 5 molecular chains without branchings and without cross-links . The preferred cc— olefin is octene.
The copolymer density ranges from 0.900 to 0.935 g/cπ and melt index from 0.7 to 4.0. The expression "polymeric alloy" - also known as "catalloy" -
2o means a product obtained by catalytic reaction composed of a matrix consisting of propylene homopolymer and a disperse phase (copolymer) .
In particular, the disperse phase of said alloys may consist of α— olefins of the C2-C or C -C/1 type . Density is 0.88 to 0.90 g/ci- and melt index is 0.7 to 4.
The expression "ethylene-propylene random copolymer" means a synthetic product obtained from ethylene and propylene, the latter being the major component, e.g. 10% ethylene and 90% propylene.
Out of the oligomers inhibiting crystallization, the following products are suitable for the purpose: aliphatic and aromatic hydrocarbon resins , aliphatic and aromatic copolymers , such as piperylene , methylbutene , vinyltoluene , indene , α-methylstyrene, polycyclodiene , etc. , hydrogenated CQ resins , styrene, α-methylstyrene, isobutene, pinene and rosin resins , and terpene resins .
The ethylene/α-olefin linear copolymer can be hardly oriented by the twin-bubble procedure.
In fact , on approaching the crystalline melting point , the polymer loses consistency and the bubble obtained by tubular film inflation is extremely unstable.
We have found that the addition of ethylene-propylene polymeric alloy and/or of ethylene-propylene random copolymer yields a mixture that can be easily handled thanks to its wide temperature range within which the tubular film is sufficiently ductile to be blown and sufficiently tough to resist blowing pressure.
A further possibility of mixture adjustment consists in the addition of crystallization inhibitory oligomers . The present invention introduces some innovations in the
traditional twin-bubble procedure, which allow an accurate product control during the process critical phases.
According to the claimed procedure, proper proportions of the single components are mixed in a conventional slow mixer with separate mixture preparation or by an automatic mixing and metering apparatus on the extruder hopper.
Extrusion is carried out by single-screw extruders, 28-32 diameters long.
The melted mixture leaves the extruder die in a tubular form at a temperature of l8θ°C to 205°C. The tubular film diameter is a function of the desired max. stretching ratio of the final film.
As concerns polyolefins, it is usual practice to use a balanced stretching ratio in the two directions (longitudinal and transversal) , which ratio may range from 4 to 6. The stretching ratio used in the claimed procedure is 1:4.5 approx. The tubular film leaving the extruder is sized and cooled by a new method in respect of the conventional twin-bubble extrusion technique. In particular, the tubular film, which is still hot, is sized by passing between an outer ring, wherefrom a liquid coolant at 15°C-25°C flows continuously, and a mould, internal to the tubular film, which is also cooled by a liquid coolant at 15°C-25°C. The max. temperature variation along the tubular film circumference is 1°C. A more uniform thickness and a greater
homogeneity of the extruded material are thus secured.
By internal and external cooling the tubular film temperature drops to 2δ°-32°C in few seconds, preferably within 4 to 9 sec.
The water leaving the outer ring adheres, as a liquid film, to the tubular film outer surface and flows to the chamber underneath.
This provides an accurate control of the rate of crystal formation in the product.
The cold tubular film is then fed to an IR-ray or hot-air oven where it is heated to a temperature close to softening. Once heated to the desired temperature, the tubular film is inflated with compressed air and expanded in the transversal direction.
This results in a transversal orientation of the molecules.
The tubular film inflation is carried out by controlling the operating temperature within ±1 C.
At the same time, the tubular film is stretched in the longitudinal direction by causing the pull-roll upstream of the oven and the final pull-roll to operate at a different speed. Once the film has undergone double hot stretching, it is rapidly cooled to maintain the inner orientation of molecules, resulting from transversal inflation and longitudinal stretching.
To this purpose, the stretched film is cooled to 25°C-35°C by blowing air at 5°C to 1 °C within 15 to 30 sec.
The film obtained according to the claimed procedure is 10 to 40 μ thick and exhibits improved characteristics over the product obtained by the known technique.
In particular, the film of the invention having thickness between 12 and 25 um exhibits:
- haze: from 1.0 to 2.0 depending on thickness
- surface gloss at 20°C: from 100 to 120 units
- tensile strength: from 100 to 120 N/mm2
- shrinking at 120°C: from 50 to 60%, balanced in the two directions
- heat seal resistance: >6θ N/mm2
- tearing propagation: from 10 to 25 g depending on thickness. Furthermore, the procedure under the invention gives a film with characteristics tailored to the various uses. Thanks to the above characteristics, the film as per the present invention is suitable for the packaging sector in general and in particular for the applications requiring a good film shrinkage and adhesion to the packed product as well as a good mechanical and heat seal resistance. For example, the claimed film is particularly fit for the packaging of vegetables, boxes, food also of irregular shape, books and magazines, multiple packed products, etc.
The following examples are conveyed by way of illustration, not of limitation.
EXAMPLE 1
A single-layer film, 15 μω thick, consisting of the following raw materials was produced.
The basic polymer used was linear polyethylene containing 8 % by wt. octene (melt index 1 and sp. gr. 0.923), in particular Clear Flex FG 308 produced by Enichem Polimeri. Said polymer was added with 20% by wt. propylene-ethylene polymeric alloy (melt index 0.8 and density 0.89 g/cm^) , in particular the elastomeric copolymer Hi Fax 7023 XEP produced by HIM0NT.
The crystallinity inhibitor was a completely saturated hydrogenated hydrocarbon resin , Eastotac 140 produced by Eastman Kodak , having molecular weight of 900 approx . and Brookfield viscosity of 1000 approx . Said resin , after dispersion in low density polyethylene ( 50% ) to give the masterbatch (Prisma AD WAX 90237 produced by Frilvam) was added to the basic polymer mixture in a 5% amount equivalent to 2.5% pure resin. Finally, antiblock and sliding additives were used to improve film handling in production and application phases . In particular , 0.5% micronized silicon dioxide was used as antiblock agent (equivalent to 1% masterbatch of type AB 6004 produced by Constab) . The operating conditions were as follows: - temperature of the melted material leaving the die: l8l°C
- cooling water: 19°C ± 1
- cooling temperature of tubular film leaving the die: 30°C
- cooling time of tubular film leaving the die: 5 sec
- diameter of tubular film leaving the die: 180 mm - longitudinal/transversal stretching ratio: 4.5
- tubular film blowing temperature: 120 C
- cooling temperature of stretched tubular film: 30°C
- cooling time of stretched tubular film: 20 sec.
Table 1 shows the characteristics of the film obtained and, for the purpose of comparison, the characteristics of commercial product CLYSAR LLP (DuPont).
The film obtained according to Example 1 showed an improved tear strength in respect of CLYSAR LLP.
EXAMPLE 2 The procedure of Example 1 was repeated with the difference that the mixture of raw materials was further added with ethylene-propylene random copolymer (melt index 1.8), in particular with 10% Moplen EP2 S 3 F (HIM0NT) .
The type and quantity of hydrocarbon resin and of antiblock and sliding additives remained unchanged.
The product obtained showed higher elastic modulus and improved optical characteristics. It was also stiffer than that as per
Example 1 and, therefore, more adequate for use in automatic fast packaging machines. Also handling conditions improved, the bubble stability being
higher .
The melted material temperature ranged from 185°C to 188°C and the tubular film blowing temperature was 126°C.
Table 1 shows the characteristics of the film obtained. Compared with the product as per Example 1, the film had a higher heat seal resistance and improved optical properties.
EXAMPLE 3
The procedure of Example 1 was repeated with the difference that the mixture was further added with ethylene-propylene random copolymer (melt index 4), in particular with 10% Moplen
SYL 7008 XCP (HIMONT) .
The type and quantity of hydrocarbon resin and of antiblock and sliding additives remained unchanged.
The product obtained exhibited improved heat sealing characteristics (lower sealing temperature in respect of the product as per Example 2, which means shorter sealing times and wider sealing range) . Also seal resistance was improved.
Furthermore, like in Example 2, the temperature range was wider than in Example 1, and bubble stability was the same.
Operating parameters: melted product temperature: 18 °C tubular film blowing temperature: 124°C Table 1 shows the characteristics of the film obtained. Compared with the products as per the above mentioned Examples, heat-sealed film had a high tear strength.
EXAMPLE 4
The procedure of Example 1 was repeated with the difference that the polymeric alloy was completely removed and the quantity of ethylene-propylene random copolymer (melt index 4) , in particular Moplen SYL 7008 XCP ( HIMONT ) was increased
(25%) .
The type and quantity of hydrocarbon resin and of antiblock and sliding additives remained unchanged.
The product obtained had excellent heat seal characteristics. On handling, bubble stability and thickness distribution were excellent.
Operating parameters : melted product temperature : l82°C bubble blowing temperature : 122° C
Table 1 shows the characteristics of the film obtained.
The mechanical properties were worse than in the previous cases .
EXAMPLE 5
The procedure of Example 1 was repeated with the difference that the hydrocarbon resin was added in a 1 . 5% amount in respect of the basic copolymer.
The type and quantity of antiblock and sliding addi tives remained unchanged .
The product obtained was a medium-stiff and medium-shrinkable film.
The operating conditions were similar to those of Example 1: temperature of melted product leaving the die: 183°C tubular film blowing temperature: 123 C
Table 1 shows the characteristics of the film obtained. Compared with the previous products, this film exhibited good mechanical properties and excellent tear strength.
EXAMPLE 6
The procedure of Example 1 was repeated with the difference that the basic copolymer was linear polyethylene (melt index 1.1; sp. gr. 0.920) containing 8% octene, with more uniform distribution (Dowlex NG 06 E produced by Dow Chemical).
The operating conditions were analogous to those of Example 1
(additional 5°C on extrusion) .
The film characteristics were very similar to those of Clysar LLP, as shown in Table 1.
EXAMPLE 7 (Comparison)
The procedure of Example 2 was repeated with the difference that the basic resin was added with 7% propylene-ethylene polymeric alloy and with 2% random copolymer.
All mechanical properties were worse (Table 1).
EXAMPLE 8 (Comparison)
The procedure of Example 1 was repeated without addition of polymeric alloy.
The bubble could not be maintained at stable and uniform conditions and frequent bursts occurred. No improvement even by
considerably varying all operating conditions. Significant and measurable samples could not be obtained.
TABLE 1: Film characteristics
Commercial
- CLYSAR
Ex.l Ex.2 Ex.3 Ex.4 Ex.5 Ex.6 Ex.7 LLP (Du Pont)
Thickness 15 15 15 15 15 15 15 15 μ
Tensile strength
N/mm2 120 130 110 95 125 100 85 100
Elongation at break %
125 115 130 125 130 130 90 130
Heat seal resistance 950 1100 1200 1000 1050 1100 800 1100 g/cm
Tear strength 20 15 22 18 24 16 10 10 e
Shrinking at 120"C 56 55 55 55 53 52 52 50
%
Haze % 1.7 1.4 1.4 1.2 1.4 1 1.3 1
Gloss
(photoelectric cell units) 100 105 105 105 100 110 100 110
Elastic modulus 348 360 340 300 352 315 350 300
N/mm
Claims
CLAIMS 1. Procedure for the preparation of a single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene comprising the steps of: a) preparing a mixture consisting of: - an ethylene/α-olefin linear copolymer, - a polymeric alloy and/or an ethylene-propylene random copolymer, and optionally - a crystallization inhibitor; b) extruding, in the melted state, the mixture obtained under a) ; c) rapid cooling of the tubular film leaving the extrusion die to 28°C to 3 "C and subsequent heating to a temperature close to softening; d) biaxially orienting the film by the twin-bubble technique; e) rapid cooling of the bioriented film to 25°C-35°C 2. The procedure according to claim 1 wherein said ethylene/α- olefin linear copolymer contains from 4 to 8% by wt. α-olefin selected out of the group consisting of butene, octene, hexene, and α-methylpentene. 3- The procedure according to claim 1 wherein said ethylene/α- olefin linear copolymer has density ranging from 0.900 to 0.935 g/cm3 and melt index ranging from 0.7 to 4.0. 4. The procedure according to claim 1 wherein said polymeric
alloy is a product obtained by catalytic reaction, composed of a matrix consisting of a propylene homopolymer and a disperse phase consisting of C2-C ct—olefins. 5- The procedure according to claim 1 wherein said ethylene- propylene random copolymer is obtained by the synthesis of ethylene and propylene, the latter being the major component. 6. The procedure according to claim 1 wherein said crystallization inhibitor is selected out of the group consisting of aliphatic and aromatic hydrocarbon resins, piperylene, methylbutene, vinyltoluene, indene, α-methylstyrene, styrene, pinene and rosin resins, and terpene resins. 7- The procedure according to claim 1 wherein said mixture prepared under step a) contains 10 to 40% by wt. of said polymeric alloy in respect of said ethylene/α-olefin linear copolymer and/or 10 to 50% of said ethylene-propylene random copolymer and, if necessary, 1 to 20% of said crystallization inhibitor. 8. The procedure according to claim 1 wherein said cooling of step c) causes the tubular film temperature to drop to 28°C to 32°C in 4-9 seconds. 9. The procedure according to claim 1 wherein said biaxial orientation is obtained at a longitudinal/transversal stretching ratio of 1:4.5. 10. The procedure according to claim 1 wherein said cooling of
step e) causes the tubular film temperature to drop to 25 °C to 35°C in 15-30 seconds . 11 . Single-layer biaxially oriented heat-shrinkable film made of composition comprising: - a linear low density polyethylene, - an ethylene/α-olefin linear copolymer with 4-8% by wt . α-olef in , - a polymeric alloy and/or an ethylene-propylene random copolymer, and optionally - a crystallization inhibitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU64278/94A AU6427894A (en) | 1993-03-23 | 1994-03-17 | Single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ITMI930555A IT1272132B (en) | 1993-03-23 | 1993-03-23 | BOX WITH MODULAR MODULAR ELEMENTS FOR WINDOWS |
| ITMI93A000553 | 1993-03-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO1994021726A2 true WO1994021726A2 (en) | 1994-09-29 |
| WO1994021726A3 WO1994021726A3 (en) | 1994-11-24 |
Family
ID=11365462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP1994/000852 WO1994021726A2 (en) | 1993-03-23 | 1994-03-17 | Single-layer biaxially oriented heat-shrinkable film comprising linear low density polyethylene and relevant production procedure |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU6427894A (en) |
| IT (1) | IT1272132B (en) |
| WO (1) | WO1994021726A2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6689436B2 (en) | 1995-12-18 | 2004-02-10 | Basell Technology Company Bv | LLDPE-based thermoshrinkable films |
| EP1729272A1 (en) * | 2005-03-01 | 2006-12-06 | Bischof+Klein GmbH & Co. KG | Heat-shrinkable polymer label |
| US7387826B2 (en) | 2003-12-31 | 2008-06-17 | Boston Scienitific Scimed, Inc. | Medical device with varying physical properties and method for forming same |
| WO2008118554A1 (en) * | 2007-03-23 | 2008-10-02 | Exxonmobil Oil Corporation | Films for use in high strength bags |
| CN113165327A (en) * | 2018-12-28 | 2021-07-23 | 陶氏环球技术有限责任公司 | Laminated structure and flexible packaging material incorporating the same |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0321220A2 (en) * | 1987-12-15 | 1989-06-21 | Mitsui Petrochemical Industries, Ltd. | Easily openable heat seal material |
| EP0369658A2 (en) * | 1988-11-16 | 1990-05-23 | Sumitomo Chemical Company, Limited | Polypropylene stretched film |
| EP0423387A1 (en) * | 1989-10-18 | 1991-04-24 | Showa Denko Kabushiki Kaisha | Low-temperature heat-shrinkable film |
| EP0434322A1 (en) * | 1989-12-18 | 1991-06-26 | E.I. Du Pont De Nemours And Company | Improved heat shrinkable polyolefin film |
| EP0519837A1 (en) * | 1991-06-21 | 1992-12-23 | Ecp Enichem Polymeres France | Compositions containing ethylene coplymers and films thereof |
-
1993
- 1993-03-23 IT ITMI930555A patent/IT1272132B/en active IP Right Grant
-
1994
- 1994-03-17 AU AU64278/94A patent/AU6427894A/en not_active Abandoned
- 1994-03-17 WO PCT/EP1994/000852 patent/WO1994021726A2/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0321220A2 (en) * | 1987-12-15 | 1989-06-21 | Mitsui Petrochemical Industries, Ltd. | Easily openable heat seal material |
| EP0369658A2 (en) * | 1988-11-16 | 1990-05-23 | Sumitomo Chemical Company, Limited | Polypropylene stretched film |
| EP0423387A1 (en) * | 1989-10-18 | 1991-04-24 | Showa Denko Kabushiki Kaisha | Low-temperature heat-shrinkable film |
| EP0434322A1 (en) * | 1989-12-18 | 1991-06-26 | E.I. Du Pont De Nemours And Company | Improved heat shrinkable polyolefin film |
| EP0519837A1 (en) * | 1991-06-21 | 1992-12-23 | Ecp Enichem Polymeres France | Compositions containing ethylene coplymers and films thereof |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6689436B2 (en) | 1995-12-18 | 2004-02-10 | Basell Technology Company Bv | LLDPE-based thermoshrinkable films |
| US7387826B2 (en) | 2003-12-31 | 2008-06-17 | Boston Scienitific Scimed, Inc. | Medical device with varying physical properties and method for forming same |
| US7601285B2 (en) | 2003-12-31 | 2009-10-13 | Boston Scientific Scimed, Inc. | Medical device with varying physical properties and method for forming same |
| US7842024B2 (en) | 2003-12-31 | 2010-11-30 | Boston Scientific Scimed, Inc. | Medical device with varying physical properties and method for forming same |
| EP1729272A1 (en) * | 2005-03-01 | 2006-12-06 | Bischof+Klein GmbH & Co. KG | Heat-shrinkable polymer label |
| WO2008118554A1 (en) * | 2007-03-23 | 2008-10-02 | Exxonmobil Oil Corporation | Films for use in high strength bags |
| US8124243B2 (en) | 2007-03-23 | 2012-02-28 | Exxonmobil Oil Corporation | Films for use in high strength bags |
| CN113165327A (en) * | 2018-12-28 | 2021-07-23 | 陶氏环球技术有限责任公司 | Laminated structure and flexible packaging material incorporating the same |
| CN113165327B (en) * | 2018-12-28 | 2023-10-03 | 陶氏环球技术有限责任公司 | Laminated structure and flexible packaging material incorporating same |
Also Published As
| Publication number | Publication date |
|---|---|
| AU6427894A (en) | 1994-10-11 |
| ITMI930555A1 (en) | 1994-09-23 |
| ITMI930555A0 (en) | 1993-03-23 |
| IT1272132B (en) | 1997-06-11 |
| WO1994021726A3 (en) | 1994-11-24 |
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