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
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J101/00—Adhesives based on cellulose, modified cellulose, or cellulose derivatives
  • C09J101/08—Cellulose derivatives
  • C09J101/16—Esters of inorganic acids
  • C09J101/18—Cellulose nitrate
• • 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
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
  • C08L2666/04—Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/08—Homopolymers or copolymers of acrylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
  • C08L71/02—Polyalkylene oxides

Definitions

• the invention relates to a multilayer film, a method for producing this multilayer film and its use in flexible packaging.
• Flexible packaging generally consists of the base carrier materials paper, aluminum foil and / or plastic film. By combining with other materials, such as films that can consist of different thermoplastic polymers, a multilayer film in the form of a film composite with a wide variety of properties can be constructed, which in addition to the basic requirement of mechanical protection barrier properties against liquids, light, gases and Aromas.
• Flexible packaging is widely used in both the food and non-food sectors. For example, flexible packaging is used to package sterile medical items, such as syringes, bandages, or gloves. In the cosmetics sector, flexible packaging is used, for example, to pack soap, shower gel or hair shampoo.
• multilayer films are used as flexible packaging material to encase aroma-tight cigarette packaging.
• flexible packaging is used to pack sausage, coffee, pasta, soup cubes, baked goods, confectionery (e.g. chocolate bars) and snack food (e.g. potato chips).
• Snack food is mentioned here by way of example for foods that can be sensitive to oxygen and / or light and / or dry out quickly or tend to absorb unwanted moisture and undesirable flavor absorption or loss.
• Multilayer films that are metallized are often used to package these foods. The metallization is usually carried out in a vacuum by vapor deposition of metals or metal oxides, preferably aluminum, as a thin layer of approximately 30 to 80 nanometers on one side of the film.
• the metal or metal oxide layers have barrier properties, in particular against water vapor and light and thus protect the fats contained in snack food, for example, which are susceptible to photooxidation, from becoming rancid.
• the barrier properties are increased by adhesives which are used to bond two or more materials, for example plastic films, to produce a composite film.
• Multi-layer films in the form of composite films are produced by laminating a base carrier material, hereinafter referred to as carrier film, with other films to form a composite film, usually in the dry lamination process.
• Dry lamination is understood to mean the large-area, continuous connection of flexible foils by gluing, the gluing taking place in the dry but still adhesive-active state after previous drying. Dry lamination can be done in-line after printing (1-step process) or off-line (2-step process).
• Two-component (2-component) laminating adhesives in particular 2-component polyurethane adhesives, and hot-melt adhesives are used for bonding.
• the application amount of the laminating adhesive is in the range from approx.
• Disadvantages of dry lamination with laminating adhesives based on polyurethanes are the waiting times of approximately 2 hours to 48 hours before the curing process of the adhesive is complete and additional films can be added to the composite film or the composite film into the finished one Shape can be cut. Before the corresponding articles, in particular foodstuffs, can be packaged, it must be ensured that the composite film is free of any migration-capable monomers, in particular monomeric diisocyanates, from the laminating adhesive that may still be present initially. As a rule, further waiting times of the order of 5 to 7 days must be observed.
• a multilayer film can also be produced by extrusion lamination.
• Extrusion lamination means the application in the extrusion process of olefinic homo- or copolymers in liquid form, in particular polyethylene, from slot dies to the films (webs) to be connected, which are usually pretreated with primers.
• Primers are base coats with e.g. B. adhesion-promoting, passivating and / or corrosion-inhibiting effect, which are applied in very thin layers (approx. 1 g / m 2 ). In most cases, they consist of dilute solutions of the adhesive base materials that are also to be used for the subsequent bonding.
• Extrusion lamination is usually carried out off-line, i.e. not in a continuous process after printing.
• the application amount of the olefinic homo- or copolymers in liquid form used in the extrusion lamination is approximately 12 g / m 2 to approximately 20 g / m 2 , which means that the total weight of such a multilayer film is significantly higher than the weight of a comparable multilayer -Foil made using dry lamination.
• the flexible packaging is sealed by sealing.
• the multi-layer film as a single film or as a composite film must have at least one sealable layer which is located on the outside, the inside or on the outside and inside of the single film or the composite film.
• the term "sealing" is generally understood to mean that a soft sealing medium sets in an adhesive manner. Heat input and / or a minimum sealing pressure are required for this. Accordingly, a distinction is made between heat sealing and cold sealing, with the question of which type of sealing is used, for example, of the materials used , the object to be packaged (e.g. its sensitivity to heat) and the type of packaging machine.
• Cold sealing adhesives are used for cold sealing, which cause two polymer layers to be bonded at approx. Room temperature under high pressure.
• Cold seal adhesives are mainly applied as aqueous dispersions in an amount of 1 - 6 g / m 2 to the polymer to be bonded and are based on rubber and rubber-like polymers, PVDC (polyvinylidene chloride), PVAC (polyvinyl acetate) and poly (meth) acrylates.
• PVDC polyvinylidene chloride
• PVAC polyvinyl acetate
• a disadvantage of cold seal adhesives is that they can only be sealed against themselves and often have insufficient adhesion.
• heat seal dispersions, heat seal lacquers, hot melt adhesives as well as films made of thermoplastic elastomers and extrusion coatings are used for the heat sealing.
• Heat-seal dispersions are predominantly PVDC, PVAC, poly (meth) acrylate or latex-containing dispersions which, after the water has evaporated, form sealable, dry and generally transparent coatings when applied in quantities of approximately 2 to 15 g / m 2 .
• a disadvantage of coatings made from heat-seal dispersions is often the tendency to stick with certain printing inks.
• heat seal lacquers In contrast to the heat seal dispersions, organic solvents are used in the heat seal lacquers using the same or similar polymers.
• the application amount of the heat seal lacquer is approx. 1 to 12 g / m 2. As a rule, heat seal lacquer cannot be used for sealing against different materials.
• Heat seal adhesives based on hot melt adhesives generally contain ethylene-vinyl acetate copolymers as base materials, which are deposited on the substrate by roller application or by extrusion.
• Coextrudates also belong to this group, whereby coextrudates mean multilayer films The layers of which are extruded to be melted together in one operation, extrusion. All polymers, preferably elastomers, which are thermoplastic in a temperature range of about 50 to about 220 ° C. are sealable or weldable.
• PE Polyethylene
• carrier films such as aluminum, polypropylene, polyester and polyamide enables a variety of packaging material specifications.
• Peelable sealing at low sealing temperatures of foils with certain other foils or deep-drawn cups is obtained by coextrusion coatings from PE-EVA blends. Also at low sealing temperatures, but with high seal seam strengths, special polyethylene copolymers which contain carboxylate groups and which partially contain zinc or sodium ions as the counter ion seal.
• WO 00/39200 discloses a coextruded BOPP film with peelable sealing properties, the film being printed in a grid-free manner in a sealing area left free of color with a thermoplastic lacquer which comprises at least one polyvinyl butyral (PVB) or at least one ethylene-vinyl acetate copolymer (EVA copolymer).
• DE 100 02 167 discloses a highly transparent, high-gloss, flame-retardant, UV-stable, thermoformable film which is equipped with a heat seal lacquer or a heat seal layer on at least one surface side.
• the film can be sealed against itself or other materials at temperatures below 150 ° C (page 2, lines 56-57).
• the heat seal layer consists of polyolefins, copolymers thereof, polyvinylidene chloride, special cover sealing lacquers, preferably polyethylene, in particular LDPE (claim 9). No suggestions can be found in this document for the selection of the heat seal lacquer.
• DE 197 07 786 discloses a plastic film for the production of packaging containers, in which one outside of the film is coated with a sealing lacquer and the opposite outside with a lacquer based on acrylate.
• the acrylate-based varnish fulfills the function of a "release coat” and prevents plastic films lying one above the other from sticking together during storage (page 6, lines 1 to 7). Films in this configuration are not particularly suitable for sealing the outside with the opposite outside.
• US 6,077,602 discloses a heat sealable polyolefin film containing a polyolefin substrate with a first and a second side.
• the first side has a polymeric coating based on a nitrile monomer and on the second side a metal is deposited or a polymer coating based on acrylic polymer.
• the coating on the first side can be sealed against itself or against the coating on the second side (page 4, lines 37-61).
• DE-OS-29 00 291 discloses a coating composition for polyolefin products based on methmethacrylate / butyl methacrylate copolymers, polyester resin and nitrocellulose of medium viscosity. It is not clear from the laid-open specification whether sealing from an outer side coated with this coating composition to the opposite outer side not coated with this coating composition is possible and intended.
• the object of the present invention was therefore to provide inexpensive multilayer films for flexible packaging.
• Another task was to provide multilayer films for flexible packaging, which enable sealing against different materials, preferably against printed and / or metallized surfaces.
• the object of the invention to provide films which can be used for packaging, in particular for packaging foodstuffs, without complex process steps and directly, that is to say without prolonged intermediate storage.
• the object is achieved by a multilayer film in which an outside is coated with a first hot-seal adhesive and the opposite outside has a layer based on a polyolefin or polyvinyl compound, the first hot-seal adhesive
• A) contains cellulose nitrate and acrylic polymers
• the multilayer film contains at least one carrier film (A1).
• the carrier film (A1) consists of plastic, paper or metal.
• the carrier film (A1) consists of a plastic film.
• the carrier film (A1) can be combined with other films made of plastic or metal to form a composite film and contain layers of paper, cardboard, metal or adhesive.
• the carrier film (A1) has a weight of 15 to 45 g / m 2 , preferably 25 to 42 g / m 2 and particularly preferably 30 to 38 g / m 2 and is usually produced continuously in the form of web goods by processes known to the person skilled in the art.
• the carrier film (A1) preferably contains at least one polymer from the group: polyamide (PA), polyurethane (PUR), polypropylene (PP), poly (ethylene-co-vinyl alcohol) (EVOH), polyvinyl alcohol (PVOH), polyethylene terephthalate (PET) , Polyethylene naphthalate (PEN), polystyrene (PS) or polymethyl methacrylate (PMMA).
• PET homopolymers and copolymers which have a reduced tendency to crystallize are preferred.
• the tendency to crystallize PET is e.g. B. reduced by copolymerization of comonomers such as isophthalic acid or 1,4-cyclohexane-dimethanol.
• the carrier film (A1) can be in a non-oriented (unstretched) or monoaxial as well as biaxially oriented design.
• the carrier film (A1) consists of oriented polypropylene (OPP), in particular biaxially oriented polypropylene (BOPP).
• OPP oriented polypropylene
• BOPP biaxially oriented polypropylene
• the multilayer film is preferably a carrier film (A1) in which the one outside is coated with the first hot-seal adhesive and the opposite outside has a sealable layer based on a polyolefin or polyvinyl compound.
• the layer (B) of the first hot-seal adhesive directly or indirectly, preferably directly, essentially, that is to say preferably over the entire surface, covers an outside of the carrier film (A1) and is located on the opposite outside, which is a layer based on a polyolefin - Or has polyvinyl compound.
• "Indirectly” means that the layer (B) of the first hot-seal adhesive, for example on a layer containing printing inks, metallic layer or surface of a further film, which does not represent the carrier film (A1), but is combined with it, of the multilayers -Film is applied.
• the amount of layer (B) applied is 0.1 to 6 g / m 2 , preferably 0.3 to 4 g / m 2 and particularly preferably 0.5 to 2 g / m 2 .
• the following components are contained in the first hot-seal adhesive forming layer (B):
• V 0 to 10% by weight of at least one plasticizer, the sum of components (I) to (V) giving 100% by weight.
• the first hot-seal adhesive preferably contains the following components:
• the acrylic polymer (II) has an average molecular weight of 30,000 to 80,000.
• the acrylic polymer (II) is preferably a methyl methacrylate copolymer.
• the polyalkylene glycol (III) is preferably a water-soluble polypropylene glycol.
• the chelate compound with titanium as the central atom (IV) is preferably a compound of ethyl acetonate, acetylacetonate, lactic acid and its salts, and triethanolamine.
• Usable plasticizers (V) are monohydric or polyhydric alcohols, preferably glycol monophenyl ether, hexamethylene glycol, glycerol and in particular polyalkylene glycols with a molecular weight of 200 to 6,000. Polyethylene glycols with a molecular weight of up to about 1,000, preferably up to about 600, are preferred. Also polypropylene glycol and polybutylene glycol , as well as polymethylene glycol are useful. Conveniently, esters are used as plasticizers, e.g.
• liquid polyesters and glycerol esters such as glycerol diacetate and glycerol triacetate, as well as neopentyl glycol dibenzoate, glyceryl tribenzoate, pentaerythritol tetrabenzoate and
• alkyl monoamines and fatty acids with preferably 8 to 36 carbon atoms may also be useful.
• Plasticizers based on aromatic dicarboxylic acid esters, ie the corresponding ester of phthalic acid, isophthalic acid or terephthalic acid, are preferably used.
• the alcohol residue in these esters used as plasticizers usually has 1 to 8 carbon atoms.
• Medical white oil and naphthenic mineral oil are particularly suitable.
• the composition for layer (B) of the first hot-seal adhesive is applied in the form of a 20 to 30% strength by weight solution or dispersion in volatile organic solvent to the surface to be coated using the customary methods known to those skilled in the art.
• solvents used are ethanol, propanol, isopropanol, ethyl acetate, n-propyl acetate, acetone, methyl ethyl ketone, low-boiling hydrocarbons or mixtures of these solvents.
• the first hot-seal adhesive remains as a dry layer (B) on the outside of the multilayer films.
• one layer of the carrier film (A1) or the composite film is metallized or contains an aluminum film which is connected to the layer below, for example a plastic film, via an adhesive layer.
• the layer (B) of the first hot-seal adhesive is applied to the metallized side or to the metal foil and is sealable against an opposite outside, which has a layer based on polyvinyl. If the first hot-seal adhesive is applied to a metallic layer, the following components are also included:
• an acid from the group of phosphoric or sulfur-containing acids is preferred, for example sulfuric acid or phosphoric acid.
• Methoxyl, ethoxyl or beta-methoxylethoxyl groups can be used as RiO substituents.
• "X" is a reactive end group, preferably an amino, hydroxyl, vinyl, methacrylic or epoxy group.
• the layer (B) of the first hot-seal adhesive protects the metallized surface from dirt and gives the metal coating abrasion resistance. The coating with a protective lacquer or a removable film, which is otherwise customarily used for these purposes, is therefore eliminated.
• the first hot-seal adhesive is a high-gloss seal lacquer.
• the first hot-seal adhesive covers essentially the entire surface of the outside.
• the opposite outer side which contains a layer (A2) based on a polyolefin or polyvinyl compound, is tightly sealing against the layer (B) made of the first hot-seal adhesive. This requires a so-called “inside against outside” seal.
• the layer based on a polyvinyl compound particularly preferably contains a sealable polyacrylate composition.
• the coating of the first hot-seal adhesive is partially replaced over the entire layer thickness by the layer of a second hot-seal adhesive in such a way that both coatings together cover essentially the entire area cover the outside.
• Layer (B) of the first hot-seal adhesive is in particular partially replaced by layer (C) of the second hot-seal adhesive in the areas that are sealed against the layer (A2) on the opposite outside.
• Layer (C) of the second hot-seal adhesive is applied to the opposite side of layer (A2) based on a polyolefin or polyvinyl compound.
• the amount of layer (C) applied is 0.1 to 5 g / m 2 , preferably 0.2 to 3 g / m 2 and particularly preferably 0.3 to 1 g / m 2 .
• Layer (C) is a sealable layer made of heat seal dispersion adhesive, heat seal lacquer or hot melt adhesive.
• Components contain: i) 25 to 90% by weight, preferably 35 to 80% by weight, particularly preferably
• Components contain: i) 25 to 90% by weight of at least one ethylene-vinyl acetate copolymer, ii) 1 to 50% by weight of at least one tackifying resin, iii) 1 to 40% by weight of at least one wax-based lubricant , the sum of components (i) to (iii) being 100% by weight.
• the ethylene-vinyl acetate copolymer (i) is characterized by its vinyl acetate content of 30 to 40% by weight and a melt index of 2 to 5 g / 10 min (ASTM D 1238).
• the tackifying resin (ii) is a) hydroabietyl alcohol and its esters, in particular its esters with aromatic carboxylic acids such as terephthalic acid and phthalic acid, b) preferably modified natural resins such as resin acids from balsamic resin, tall resin or root resin, for example fully saponified balsamic resin or alkyl esters of optionally partially hydrogenated Rosin with low softening points such as methyl, diethylene glycol, glycerol and pentaerythritol esters, c) acrylic acid copolymers, preferably styrene-acrylic acid copolymers and d) Resins based on functional hydrocarbon resins.
• alkyl ester of partially hydrogenated rosin as the tackifying resin, the alkyl group preferably containing 1 to 6 carbon atoms.
• the wax (iii) to be used as a lubricant is carnauba wax, paraffin wax, oxazoline wax or a mixture of two or more of these waxes.
• Hydrocarbon resins and / or hydrogenated hydrocarbon resins (iii) the wax to be used as a lubricant (iii) a carnauba wax,
• Paraffin wax Paraffin wax, oxazoline wax or a mixture of two or more of these waxes.
• the second hot-seal adhesive for producing the layer (C) is applied in the form of a 20 to 30% strength by weight solution or dispersion in volatile organic solvent using the customary methods known to the person skilled in the art, directly or indirectly, to the surface of ( A1) applied and after application is located on the opposite side of the layer (A2) based on a polyolefin or polyvinyl compound.
• the second hot-seal adhesive can be sealed against a layer on the opposite outside based on a polyolefin compound.
• the layer based on a polyolefin compound particularly preferably contains ethylene-vinyl acetate copolymers and / or polypropylene copolymers.
• the outside, which has the layer (A2) based on a polyolefin or polyvinyl compound, is defined as the “inside” of the multilayer film.
• the side that is provided with the sealing layer (C) is called the “outside " Are defined.
• the indirect application means that the sealing layer (C) in a multilayer film is not applied directly to the carrier film (A1), but to the last layer of the composite, starting from the layer (A2) based on a polyolefin or polyvinyl -Connection as the first layer.
• the second hot-seal adhesive for example, ethyl acetate, n-propyl acetate, acetone, methyl ethyl ketone, low-boiling hydrocarbons or mixtures of these solvents are used as solvents.
• the second hot-seal adhesive remains as a dry layer (C) on the surface of the multilayer film.
• the sealing layer (C) can almost completely cover an outside of the multilayer film, for reasons of economy it is preferably applied only in areas in which sealing properties are desired. These areas can be (colored) printed, the sealing layer (C) is therefore applied both in an ink-free and ink-containing sealing area.
• the sealing layer (C) is preferably applied in certain patterns or grids, for example it is applied in strips on the respective long sides of the multilayer film. Further strips of the sealing layer (C) can be located at certain intervals across the width of the multilayer film between the longitudinally applied sealing layer (C). The distance between the strip-shaped sealing layer (C) applied over the width of the multilayer film defines the length of the individual packaging. Preferred patterns of the applied sealing layer (C) are described in WO 00/39200.
• the layer (A2) based on a polyolefin or polyvinyl compound on the opposite side of the multilayer film is produced by coextrusion, for example in the flat film or film blowing process, or is applied by lamination, extrusion lamination or extrusion coating.
• the layer (A2) based on polyolefin is against the layer (C) of the second hot Sealable adhesive sealable, the layer based on polyvinyl is sealable against the layer (B) of the first hot-seal adhesive.
• the layer (A2) contains thermoplastic polymers which melt at temperatures between 50 ° C and 200 ° C, preferably 90 ° C and 180 ° C and is sealable.
• a sealable layer is understood to be a layer which follows
• the sealable layer (A2) contains thermoplastic polymers from the group of homopolymers, alternating or random copolymers, the
• the sealable layer (A2) contains at least one polymer from the
• PET Polyethylene terephthalate
• PA polyamide
• LLDPE linear low density polyethylene
• LLDPE linear low density polyethylene
• HDPE high density polyethylene
• PP polypropylene
• PB polybutylene
• polyhexene poly-ethylene vinyl acetate
• EVA polyethylene butyl acrylate
• EAA poly ethylene ethyl acrylate
• Ethylene acrylic acid or modified polyolefin copolymers with
• modified polyolefin copolymers are polypropylene or
• Polyethylene copolymers preferred, for example by graft polymerization with monomers from the group alpha, beta-monounsaturated dicarboxylic acids
• the multilayer film can be made of an oriented homopolymer made of polypropylene (OPP) with a heat-sealable layer (A2)
• OPP polypropylene
• A2 heat-sealable layer
• Polypropylene / polyethylene copolymer exist.
• a multilayer film with only one carrier film (A1) is particularly preferred, the surface of the carrier film (A1) being identical to the sealable layer (A2).
• (A1) and (A2) preferably contain essentially OPP, biaxially oriented polypropylene (BOPP) or biaxially oriented PET.
• multilayer films can also be used in which the carrier film (A1) with the sealable surface layer (A2) has a thickness of approximately 0.2 millimeters to 2 millimeters, preferably 0.3 millimeters to 1.8 millimeters.
• the sealable layer (A2) of the multilayer film is tightly sealing or peelable (peelable) against itself or the layer (B) or (C). It is preferred in the context of the invention that the sealable layer (A2) is peelable against itself. This requires a so-called “inside against inside” seal.
• the multilayer film according to the invention can optionally be provided with functional layers, such as metallic or transparent inorganic or organic barrier layers.
• a metallic barrier layer is produced using a conventional vacuum coating process.
• Vacuum coating processes can be used to coat or metallize the composite film according to the invention with a large number of metals, for example zinc, nickel, silver, copper, gold, indium, tin, stainless steel, chromium, titanium or aluminum.
• an aluminum coating is preferred which is applied directly to the surface of the carrier film (A1) or indirectly, that is to say to a surface of a further layer of the multilayer film.
• the surface of the multilayer film - or the surface of the carrier film (A1) directly - can be pretreated.
• Corona treatment for example, makes the surface for the next one Machining process cleaned, oxidized and activated and thus improves the adhesion of the surface.
• the multilayer film can be metallized with a glossy, highly reflective surface or with a semi-gloss, weakly reflective surface, depending on whether the surface of the multilayer film or the single film (carrier film) to be metallized had a glossy or matt surface finish ,
• the multilayer film is preferably printed in the form of the composite film - or the carrier film (A1) directly.
• Printing usually takes place by horizontally introducing the carrier film web or the composite film in-line to the printing press station. It is also possible to wind the carrier film (A1) or the composite film on rolls in preparation for pressing.
• the multilayer film with a repeating design and / or other prints, for example images, decorations, or text in one or more colors, is then applied directly to the metallized or non-metallized surface of the composite film - or the carrier film (A1) directly - printed.
• gravure, gravure or flexographic printing machines are used.
• the composite film is printed on the opposite side of the sealable outer layer (A2).
• Transparent metal-filled and / or opaque printing inks are preferably applied using conventional printing processes such as rotogravure or flexographic printing processes.
• Printing inks consist of 1) colorants (pigments including fillers or dyes), 2) binders and 3) additives (e.g. drying agents, diluents, wax dispersions, catalysts or initiators for radiation drying).
• colors based on polyester resin binders are preferred, but color systems based on binders from the group: cellulose nitrate; Polyvinyl resin, such as polyvinyl chloride (PVC), polyvinyl acetate (PVAc) and copolymers based on hydroxyl-modified PVC and PVAc; Resins based on polymers and copolymers of acrylic and methacrylic acid and their esters; polyurethane; Polyamide or polyvinyl butyral (PVB) can be used.
• PVC polyvinyl chloride
• PVAc polyvinyl acetate
• Resins based on polymers and copolymers of acrylic and methacrylic acid and their esters polyurethane
• Polyamide or polyvinyl butyral (PVB) can be used.
• the layer (B) of the first hot-seal adhesive and the layer (C) of the second hot-seal adhesive are distinguished by good compatibility with commercially available printing inks.
• the first and / or second hot-seal adhesive is applied over a sealing area containing printing inks and sealable against the opposite outside.
• layers (B) and (C) are clearly transparent, so that the printed area underneath remains clearly visible.
• Layer (B) of the first hot-seal adhesive preferably in the combination that the coating of the first hot-seal adhesive is partially replaced over the entire layer thickness by the layer of the second hot-seal adhesive, replaces a film with a sealable surface layer, which is otherwise usually inserted into the film composite and is sealed as a welding film against the sealable outer layer (A2) of the multilayer film.
• the welding film no longer needs the adhesive which is otherwise usually used to laminate the replaced film to film crosslinking.
• FIGS. 1 and 2 This is illustrated by FIGS. 1 and 2, with FIG. 1 representing the prior art and FIG. 2 a special embodiment of the invention.
• the figures serve only to illustrate the invention and do not reflect the actual size relationships.
• the invention also relates to processes for producing a multilayer film, in which a) a first hot-seal adhesive and optionally a second hot-seal adhesive in the form of a 20 to 30% strength by weight solution or dispersion of the particular composition in volatile organic solvents on the outside of a multilayer film which has a layer of a polyolefin or polyvinyl compound on the opposite outside and b) evaporates the solvent, so that essentially the entire area of the outside is covered by a layer from the first Hot-seal adhesive and possibly a layer of the second hot-seal adhesive is covered, the coating of the first hot-seal adhesive being partially replaced over the entire layer thickness by the layer of the second hot-seal adhesive.
• the hot-seal adhesives are applied using the customary methods known to those skilled in the art.
• the first and second hot-seal adhesives are applied to the surface to be coated using appropriate application devices and essentially cover directly or indirectly an outside of the carrier film (A1), the sealable layer based on (A2) a polyolefin being on the opposite outside - or polyvinyl compound.
• Uniform means that (B) and (C) have the same layer thickness.
• the layer (B) of the first hot-seal adhesive is sealed against the opposite outside, which has a layer based on a polyvinyl compound.
• the layer (C) of the second hot-seal adhesive is sealed against the opposite outside, which has a layer based on a polyolefin compound.
• the sealing of the layer (B) and / or the sealing layer (C) takes place as an "outside against inside sealing" at the usual sealing temperatures, usually from 100 to 160 ° C., and the usual sealing pressure, usually between 0 , 3 and 6 bar, against the layer (A2) based on a polyolefin or polyvinyl compound.
• the sealable multi-layer film has peelable properties with "inside against inside sealing", which means that the flexible packaging made from it can be opened easily and without tears without tearing, despite the technically unavoidable fluctuations in raw materials, as well as variations in printing conditions, sealing temperatures and Application weights over a wide tolerance range largely maintain the seal strength.
• the layer (B) of the first hot-seal adhesive gives the surface of the first hot-seal adhesive
• Composite film has a lower coefficient of friction and thus allows better processing.
• the multilayer film according to the invention is more flexible for producing
• Multi-layer films for packaging sterile medical items for example
• the multilayer film according to the invention is suitable for the following reasons.
• Packaging of articles from the cosmetics sector for example soap, shower gel or hair shampoo.
• the multilayer film according to the invention is preferably suitable for
• Packaging of food for example sausage, coffee, pasta,
• Soup cubes, baked goods, confectionery and snack food Soup cubes, baked goods, confectionery and snack food.
• the invention therefore also relates to flexible packaging which can be produced from the multilayer film according to the invention.
• Hardener 6800 from Henkel KGaA, coated and laminated against a further coextruded OPP film with a weight of 18 g / m 2 (from: Mobil Chemical).
• a coextruded OPP film with a weight of 34 g / m 2 (from: Mobil Chemical) is printed, as well as with 1.0 g / m 2 of the first hot-seal adhesive and 0.6 g / m 2 of the second Hot-seal adhesive coated. Sealing is carried out using a heated sealing tool "inside” against “outside”, the lacquered surface being sealed against the sealable surface of the coextruded OPP film.
• Adhesive for example from Henkel KGaA (Liofol UK 3640 with hardener
• a coextruded OPP film with a weight of 34 g / m 2 (from: Mobil Chemical) is printed, and with 1.0 g / m 2 of the first hot-seal adhesive high-gloss lacquer and 0.4 g / m 2 of second hot-seal adhesive coated.
• Sealing is carried out using a heated sealing tool “inside” against “outside”, the lacquered surface being sealed against the sealable surface of the coextruded OPP film.
• a standard printing machine for roll goods was used for the tests (Schiavi rotary gravure printing machine type: "Patriot").
• the hot-seal adhesives were applied by means of segmented anilox roller application, the first hot-seal adhesive and then the second hot-seal adhesive being applied sealing area (sealing zone) of the outside of the film was coated with the second hot sealing adhesive, the remaining area of the outside of the film was coated with the first hot sealing adhesive, so that both hot sealing adhesives together covered an outside of the film.
• the outside coated with the hot sealing adhesives was sealed against the opposite outside made of coex OPP at 130 ° C-140 ° C and 3 bar with a sealing time of 1 second.
• a sealing machine from Brugger-Feinmechanik / Kunststoff, type HSG-C1237 (sealing jaws 150 x 110 mm, teflonized) was used for sealing.
• the multilayer films according to the invention produced in (I and II) stand out in comparison to the corresponding comparison multilayer films. Films from the prior art have a low overall weight and equally good bond and seal seam adhesion values.
• Example II In the case of a one-sided metallized OPP film according to packaging for snack food, Example II, the metallic surface was pretreated with the primer Vitel B 2200 B (approx. 4% high molecular weight polyester, 96% ethyl acetate; from Bostik) and then coated with both hot-seal adhesives.
• the primer Vitel B 2200 B approximately 4% high molecular weight polyester, 96% ethyl acetate; from Bostik
• the first hot-seal adhesive was a mixture of 98% by weight of recipe a) from Table 1, 1% phosphoric acid and 1% epoxysilane (Silquest A 187 ( Cromptan (OSI)) or Silan Z 6040 (Dow Corning) used.
• F metal layer (there may be a laminating adhesive layer (E) between (F) and (A1))

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
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• Wrappers (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Adhesive Tapes (AREA)

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• 2003
  • 2003-03-12 DE DE10311125A patent/DE10311125A1/de not_active Withdrawn
  • 2003-03-24 CN CNA038075474A patent/CN1646312A/zh active Pending
  • 2003-03-24 KR KR10-2004-7015510A patent/KR20040105822A/ko not_active Application Discontinuation
  • 2003-03-24 PL PL03371193A patent/PL371193A1/xx not_active Application Discontinuation
  • 2003-03-24 JP JP2003580074A patent/JP2005528238A/ja not_active Withdrawn
  • 2003-03-24 MX MXPA04007625A patent/MXPA04007625A/es not_active Application Discontinuation
  • 2003-03-24 BR BR0308861-8A patent/BR0308861A/pt not_active IP Right Cessation
  • 2003-03-24 EP EP03714876A patent/EP1490218A2/de not_active Withdrawn
  • 2003-03-24 AU AU2003219095A patent/AU2003219095A1/en not_active Abandoned
  • 2003-03-24 WO PCT/EP2003/003020 patent/WO2003082570A2/de not_active Application Discontinuation
  • 2003-03-24 RU RU2004131871/04A patent/RU2004131871A/ru not_active Application Discontinuation

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