Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31725—Of polyamide
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31725—Of polyamide
  • Y10T428/3175—Next to addition polymer from unsaturated monomer[s]

Definitions

• the invention relates to a multilayer, weldable flat film, from which tubular films are produced in a known manner by welding, which are used for packaging and wrapping foodstuffs, in particular pasty foods, the multilayer flat film being laminated by laminating at least two flat films, which in turn are a - Can be multilayer and biaxially stretched, is produced.
• Multi-layer, weldable flat films which are produced by lamination, are known.
• Tubular foils of all types can be produced from such multilayer flat foils by welding for packaging purposes, either by bending the flat foil together to form a tube in a known manner and the mutually abutting opposite edges being connected to one another by a sealing strip running in the longitudinal direction.
• a second possibility is to bend the flat film together to form a tube by letting the opposite edges overlap and by welding the overlapping areas together.
• the third possibility of forming a tubular film from a flat film is to bend the flat film together to form a tubular film and to weld opposite edge regions along the longitudinal axis to form a longitudinal fold in which the same sides of the flat film lie against one another.
• such foils In addition to high water vapor and oxygen impermeability, such foils have to meet high requirements with regard to weldability, in particular strength of the weld seam.
• the object of the invention is therefore to provide a flat film which fulfills the above-mentioned requirements.
• the surface layers are made up of at least one sealable copolyamide.
• Such known copolyamides are prepared from monomers which are selected from the group consisting of caprolactam, laurolactam, omegaaminoundecanoic acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, tetramethylenediamine, pentamethylenediamine diamine, octamethylene diamine, hexamethylene diamine, hexamethylene diamine, octamethylene diamine, hexamethylene diamine, hexamethylene diamine, hexamethylene diamine, octamine diamine diamine, hexamine diamine diamine, and amine diamine diamine, hexamine diamine diamine, octamine diamine diamine, hexamine diamine diamine, octamine diamine,
• the addition of an amorphous polyamide and / or a homopolyamide and / or a modified polyolefin to a copolyamide in the surface layer significantly increases the seal seam strength compared to pure copolyamide, or high seal seam strengths are achieved even at lower sealing temperatures.
• the film according to the invention thus has considerable advantages in terms of application technology.
• the amorphous polyamides used for the surface layer are polyamides whose glass transition temperature in the dry state is between 50 and 200 ° C. Examples include polyamide 6I 6T, polyamide 6-3 -T and polyamide 61.
• Polyamides which can be prepared from the same monomers as the copolyamides already described above are used as homopolyamides for the surface layer.
• the homopolyamides can have both aliphatic and partly aromatic character.
• modified polyolefins modified homo- or copolymers of ethylene and / or propylene and optionally further linear alpha olefms with 3 to 8 carbon atoms, which are monomers from the group of alpha-beta-unsaturated dicarboxylic acids, preferably maleic acid, fumaric acid, itaconic acid or their acid anhydrides, acid esters, Acid amides or acid imides grafted on.
• the main component of the respective surface layer is a sealable copolyamide or a mixture of sealable copolyamides, this main component being present in amounts between 50 and 95% by weight.
• the other components, amorphous polyamide, homopolyamide and modified polyolefin, can be mixed with the main constituent in amounts of 0 to 30% by weight, based on the entire surface layer.
• At least one further layer is located between the two surface layers of the flat film according to the invention.
• the additional layer or layers arranged between the two surface layers serve to give the flat film, in addition to the weldability, other desired properties such as a high barrier to oxygen and water vapor, high puncture resistance or good mechanical properties.
• Materials that can form the layers between the two surface layers are polyamides, polyolefins, modified polyolefins and ethylene vinyl alcohol copolymers. Mixtures of these materials with one another can also be used. Additional layers of adhesion promoters may also be present if adjacent layers do not have sufficient adhesion to one another.
• Polyamides as the intermediate layer can be homo- and / or copolyamides which are produced from monomers which are selected from the group caprolactam, laurolactam, omegaaminoundecanoic acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecandicarboxylic acid, terephthalic acid, isophthalic acid, tetramethylene diamine diamine, hexamethylene diamine, octamethylene diamine and xylylenediamine.
• Preferred homo- and copolyamides are polyamide 6, polyamide 12, polyamide 66, polyamide 610, polyamide 612, polyamide MXD6, polyamide 6/66, polyamide 6/12 and polyamide 6I / 6T.
• the wall thickness of the polyamide intermediate layer is between 5 and 30 ⁇ m.
• Polyolefins as an intermediate layer are homopolymers of ethylene or propylene and / or copolymers of linear alpha olefins with 2 to 8 carbon atoms. Linear low-density polyethylene, high-density polyethylene, polypropylene homopolymer, polypropylene block and polypropylene random copolymer are preferably used for this layer.
• the wall thickness of the polyolefin intermediate layer is between 5 and 30 ⁇ m.
• the modified polyolefins as the intermediate layer are copolymers of ethylene or propylene and optionally further linear alpha-olefins having 3 to 8 carbon atoms with alpha-beta-unsaturated carboxylic acids, preferably acrylic acid, methacrylic acid and / or their metal salts and / or their alkyl esters or corresponding graft copolymers of the monomers mentioned onto polyolefins or partially saponified ethylene-vinyl acetate copolymers, which are optionally graft-polymerized with an alpha-beta-unsaturated carboxylic acid and have a low degree of saponification or mixtures thereof.
• alpha-beta-unsaturated carboxylic acids preferably acrylic acid, methacrylic acid and / or their metal salts and / or their alkyl esters or corresponding graft copolymers of the monomers mentioned onto polyolefins or partially saponified ethylene-vinyl
• the modified polyolefins can be modified homo- or copolymers of ethylene and / or propylene and, if appropriate, further linear alpha-olefins having 3 to 8 carbon atoms, the monomers from the group of the alpha-beta-unsaturated dicarboxylic acids, preferably maleic acid, fumaric acid, itaconic acid or whose acid anhydrides, acid esters, acid amides or acid imides contain grafted on.
• the wall thickness of the intermediate layer made of modified polyolefin is between 5 and 30 ⁇ m.
• the ethylene vinyl alcohol copolymers as an intermediate layer are produced by completely saponifying copolymers of ethylene with vinyl acetate.
• the ethylene content in the ethylene-vinyl alcohol copolymers is between 27 and 48 mol%.
• ethylene-vinyl alcohol copolymers are preferred, the ethylene content of which is between 34 and 48 mol%.
• the wall thickness of the intermediate layer made of ethylene vinyl alcohol copolymer is between 3 and 20 ⁇ m.
• adhesion promoters are used in the intermediate layer, these are homopolymers or copolymers of ethylene and / or propylene and, if appropriate, further linear alpha-olefins having 3 to 8 carbon atoms, the monomers from the group of the alpha-beta-unsaturated dicarboxylic acids, preferably maleic acid , Fumaric acid, itaconic acid or their acid anhydrides, acid esters, acid amides or acid imides grafted on.
• the number indices 1,2 denote several layers from the same raw material class.
• a ⁇ B // DA 2 ; A1B // EA2; A 1 D / EA a ; A1B // C // A2
• A, EB // CFA 2 ; A 1 F ⁇ E // BF 2 A 2 ; A ⁇ D ⁇ E7 BD 2 Aa; A 1 F 1 C / EF 2 A 2 ; A 1 F 1 C // BFA 2 ; A1F1B1 / YB2F2A2; Aid / ZBiBaBs / VA .; A1FB1 // B2EA3; A ⁇ D // B ⁇ B 2 / fA2
• a ⁇ D 1 // B ⁇ EB 2 // D 2 A 2 ; A1F1C // BEF2A2; A ⁇ D 1 // B 1 B 2 B 3 // D 2 A 2 ; A ⁇ F 1 C 1 // B // C 2 F 2 A 2 ; A ⁇ F ⁇ B 1 // C // B 2 F 2 A 2
• the flat film may also contain customary auxiliaries, for example antiblocking agents, stabilizers, antistatic agents or lubricants. These auxiliaries are usually added in amounts of 0.1 to 5% by weight. Furthermore, the film can be colored by adding pigments or pigment mixtures.
• auxiliaries for example antiblocking agents, stabilizers, antistatic agents or lubricants. These auxiliaries are usually added in amounts of 0.1 to 5% by weight.
• the film can be colored by adding pigments or pigment mixtures.
• the starting foils for the lamination can be printed. If the print is on the side of the original film to which another film is applied during lamination, the print in the finished laminated film is in an intermediate layer and is therefore protected against damage during further processing of the film.
• the flat films according to the invention are produced by laminating at least two flat films, which in turn can be stretched out in one or more layers and biaxially.
• the individual films are connected to one another in a laminating system by pressing and, if appropriate, applying a laminating adhesive in such a way that the layers, the main component of which is a sealable copolyamide, form the two surface layers of the laminated flat film.
• This process makes it possible to produce wide flat films that are too wide to be used for packaging and wrapping food. In this case, it is possible to cut the wide flat films in the longitudinal direction into narrower panels, which can then be welded to tubular films of the desired dimension.
• the tubular films according to the invention have total wall thicknesses of 30 to 100 ⁇ m, preferably 40 to 80 ⁇ m. Weld strengths were determined on the tubular films according to the invention and on the comparative example.
• weld strength 50 mm wide strips were taken from the respective flat foils transversely to the running direction. Two strips each were welded to one another, welding on the one hand surface layer 1 overlapping with surface layer 2 (welding method 1) and welding on the other hand surface layer 1 with surface layer 1 (welding method 2) lying on top of one another.
• a SGPE 20 laboratory welding machine from W. Koppmaschinen was used as the welding machine. 25 mm wide strip samples were taken from the welded samples in such a way that the weld seam was transverse to the longitudinal direction of the strip. The strip samples were pulled apart on a tensile testing machine from Instron at a pull-off speed of 500 mm / min until the weld seam broke. The maximum force achieved is referred to below as weld strength.
• the flat films according to the invention show significantly higher weld seam strengths than the comparative example.
• significantly better weld seam strengths are achieved both at 180 and 200 ° C sealing temperature than in the comparative example.
• Ionomer resin Surlyn 1652 from Du Pont de Nemours GmbH, 10 ⁇ m
• 2nd layer adhesion promoter, modified polyethylene, Bynel 4140 from Du Pont de Nemours GmbH, 7 ⁇ m
• 3rd layer polyethylene (LLDPE), Dowlex 2049 E from DOW Chemical Company, 13 ⁇ m
• Ionomer resin Surlyn 1652 from Du Pont de Nemours GmbH, 10 ⁇ m
• 2nd layer adhesion promoter, modified polyethylene, Bynel 4140 from Du Pont de Nemours GmbH, 7 ⁇ m
• 3rd layer polyamide 6, Durethan B 40 F from Bayer AG, 13 ⁇ m
• Welding method 1 The following values for the weld seam strength were determined:
• Example 2 On a laminating machine, two three-layer, biaxially stretched, coextruded flat films were laminated to a six-layer flat film with the aid of a laminating adhesive, the sealable layers (1st layer in each case) forming the two outer sides of the resulting flat film.
• the layer structure of the three-layer starting foils was as follows:
• 1st layer Mix 85% polyamide 6/12, Grilon CF6S from EMS-Chemie and 5%
• 2nd layer adhesion promoter, modified polyethylene, Bynel 4140 from Du Pont de Nemours GmbH, 7 ⁇ m
• 3rd layer polyethylene (LLDPE), Dowlex 2049 E from DOW Chemical Company, 13 ⁇ m
• 1st layer Mix 85% polyamide 6/12, Grilon CF6S from EMS-Chemie and 5%
• 3rd layer polyamide 6, Durethan B 40 F from Bayer AG, 13 ⁇ m
• Welding method 1 Sealing temperature 120 ° C: 192 N / 25 mm
• Example 1 a six-layer flat film was produced by laminating two three-layer films, with the difference that the first layer of each of the two three-layer films consisted of pure polyamide 6/12, Grilon CF6S from EMS-Chemie.
• Welding method 1 The following values for the weld seam strength were determined:

Landscapes

• Laminated Bodies (AREA)
• Wrappers (AREA)

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• 2001
  • 2001-02-01 CA CA002434589A patent/CA2434589A1/en not_active Abandoned
  • 2001-02-01 WO PCT/EP2001/001065 patent/WO2002060992A1/de not_active Application Discontinuation
  • 2001-02-01 BR BR0109743-1A patent/BR0109743A/pt not_active IP Right Cessation
  • 2001-02-01 MX MXPA03006761A patent/MXPA03006761A/es unknown
  • 2001-02-01 PL PL36235501A patent/PL362355A1/xx not_active Application Discontinuation
  • 2001-02-01 HU HU0300966A patent/HUP0300966A2/hu unknown
  • 2001-02-01 EP EP01902378A patent/EP1360240A1/de not_active Withdrawn
  • 2001-02-01 US US10/470,920 patent/US20040071993A1/en not_active Abandoned
  • 2001-02-01 CZ CZ20032147A patent/CZ20032147A3/cs unknown
• 2002
  • 2002-10-01 NO NO20024714A patent/NO20024714L/no not_active Application Discontinuation

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