Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
  • D21H23/22—Addition to the formed paper
  • D21H23/46—Pouring or allowing the fluid to flow in a continuous stream on to the surface, the entire stream being carried away by the paper
  • D21H23/48—Curtain coaters
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/80—Paper comprising more than one coating
  • D21H19/82—Paper comprising more than one coating superposed
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/10—Packing paper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C5/00—Apparatus in which liquid or other fluent material is projected, poured or allowed to flow on to the surface of the work
  • B05C5/005—Curtain coaters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/30—Processes for applying liquids or other fluent materials performed by gravity only, i.e. flow coating
  • B05D1/305—Curtain coating

Definitions

• the invention relates to a method for producing a packaging material with a functional layer on a substrate using a casting method for coating the substrate.
• Paper-based products are used for many applications in the field of web-type packaging materials. In many cases and when the requirements for the barrier properties of the packaging material are low, this happens without further modifications to the same. With the help of functional coatings, packaging papers are given barrier properties against oxygen, water vapour, oil and fat and other substances.
• the requirements of the food industry in particular for sensitive products are very high and have so far usually been met by plastics or composites, for example with aluminum or plastic foils.
• the social development of the past few years has led to an increasing rethinking in the field of packaging.
• One of the demands of the market and customers on the manufacturers of packaging materials is to use more ecological materials based on paper and renewable raw materials whenever possible.
• the limit values for hazardous substances are further reduced to the lowest possible values due to legal requirements and also due to social requirements to avoid or reduce hazardous substances.
• the challenge for manufacturers of food packaging is to to achieve high barrier properties and the ecological requirements with economically justifiable processes.
• the parallel application of several layers by curtain coating is, for example, in the EP 1 416 087 B1 described.
• the already described barrier properties with regard to oxygen and water vapor as well as a sealing layer are applied to a substrate.
• Table 1 gives the formulations and the application weights for the application of a curtain made up of five individual layers by curtain coating.
• the two outer ones Layers of the curtain have a higher application weight and a comparable amount of surface-active substances compared to the inner layers. All layers contain surface-active substances. The amount of surface-active additive used for the entire product is therefore very high for the products described in this document in order to ensure sufficient quality during manufacture.
• the EP 1 666 637 A1 largely dispenses with the use of surface-active additives due to the use of solvents.
• the use of solvents is undesirable for ecological and occupational health reasons.
• the EP 1 395 705 B1 describes packaging papers with barrier properties. With curtain coating, different layers are applied in a variety of combinations. Here, too, the focus is on a functioning curtain application, which is ensured by the use of surface-active additives in all layers. The process stability is consequently bought here by the use of large amounts of surface-active additives.
• the EP 1 255 615 B1 describes the curtain coating of substrates for the production of packaging materials.
• the use of surface-active substances because of the curtain coating exceeds the required limit values.
• the invention is based on the object of providing a stable coating method according to the principle of curtain coating for the production of packaging materials that, with regard to the packaging material obtained, better meets the legal requirements with regard to the proportion of harmful substances than known packaging materials produced with curtain coating.
• Stable coating process means that the coating on a substrate will pass through a casting process can be carried out on an industrial scale without fear of material flow breaks in the curtain.
• this object is achieved by the application of functional layers to a substrate using a casting process, comprising the formation of a multi-layer, water-based curtain and the application of this curtain to the substrate, in which the outer layers of the Curtains contain surface-active additives and the difference in surface tension between the outer layers and the adjacent inner layer(s) of the curtain is at least 5 mN/m.
• the invention also relates to packaging material with a substrate and an at least three-layer application arranged thereon, which is applied to the substrate by curtain coating, the application containing at least one functional layer and the layer of the application that is in contact with the substrate and the layer of the application that is in contact with the air-contact layer of the application contain a surface-active additive and the difference in surface tension between these two outer layers and an inner layer of the application adjacent to this is at least 5 mN/m.
• the difference in surface tension of said layers is achieved by the higher concentration of surface-active additives in the coating composition for the outer layers of the curtain compared to the concentration of the inner layer(s) of the curtain.
• the inner layer(s) of the curtain may preferably be free of a surface active additive.
• the amount of surface-active additives used in the two outer streams of the curtain in contact with air in the range of 0.02 wt .-% to 0.6 wt .-%, based on the mass of the composition of the both outer layers, are limited. Consequently, the amount of surface-active additives in the obtained unprinted packaging material is limited to the range of 0.02% to 0.6% by weight. As a result, the total amount of surface-active additives, based on the mass of the curtain, is significantly limited compared to the prior art. Surprisingly, this procedure nevertheless provides a high stability of the curtain during cast coating.
• the packaging material obtained according to the invention thus has a significantly lower concentration of undesirable surface-active additives than packaging materials produced by known processes, in particular for food.
• the two sides of the packaging material described here differ.
• the "top” of the packaging material is the side on which one or more functional layers are applied. In later use, this side is in contact with the product to be packaged, for example food.
• the "bottom” of the packaging material is the side opposite the top. In subsequent use, it forms the outside of the packaging and can optionally be equipped for printing.
• the materials to be coated in the phase are referred to in which they move as a composite of multiple layers in free fall onto a substrate or a substrate web.
• the individual layers are combined and then flow as a curtain onto the substrate.
• This curtain has two surfaces that are in contact with the ambient air.
• the inner surface of the curtain is the surface that is in direct contact with the substrate after application.
• the outer surface of the curtain is accordingly the opposite surface, which later forms the contact surface with the product to be packaged.
• a functional layer within the meaning of the invention is a layer on the substrate which improves the usability of the packaging material obtained according to the invention for a specific good to be packaged or produces desired functionalities of the packaging material.
• a functional layer can provide barrier properties for any substance.
• the packaging material according to the invention or packaging material obtained according to the invention by the curtain coating process can have one or more functional layers and further layers such as an ink-receiving layer for printing, a binder layer or a separating layer (separating layer) on a substrate.
• the free-flowing, aqueous-based, multi-layered curtain contains at least three individual streams.
• the curtain is consequently a composite, formed from two outer streams of material which are in contact with air and at least one stream of material located between the outer streams of material.
• the number of material flows (layers) in the curtain between the two outer material flows in contact with air in the curtain can be 1 to 7 or more, preferably 1 to 5.
• the curtain particularly preferably contains a total of four or five material flows with the outer material flows.
• the curtain can therefore have several functional layers with different properties or different functions in the packaging material.
• the curtain can contain two streams of material with the same functionality for the packaging material. The material flows are miscible with water.
• Additional layers can be applied to the coating applied by a casting process by other coating processes.
• Other coating methods are known application techniques for web-like substrates such as melt extrusion, doctor blades and rollers.
• a dye-receiving layer, a binder layer or a release layer can be applied by such techniques.
• the curtain of wet coating layers is applied to the substrate using a so-called curtain coater.
• Surfactants for the purposes of the invention are those which are customarily used when a surface-active or interface-active effect is desired or when streams of material for curtain coating are to be stabilized.
• the surface-active additives can be anionic, cationic or amphoteric surfactants and reduce the surface tension of aqueous systems or of water.
• the two outer layers of the curtain that are in contact with air during casting contain only 0.02% to 0.4% by weight of surfactant additives.
• the intermediate layers contain fewer surfactants than the outer layers.
• the interlayers of the curtain are free of surface-active additives.
• the wet coat weight of an outer layer can be 0.5 g/m 2 to 15 g/m 2 , preferably 1.0 g/m 2 to 6.0 g/m 2 .
• the application weight of the layer applied to the substrate by curtain coating can be a total of 3 g/m 2 to 50 g/m 2 (dry), preferably 4 g/m 2 to 30 g/m 2 .
• the application weight of individual layers of the total application can be 0.3 g/m 2 to 20 g/m 2 or more (dry), but preferably 0.5 g/m 2 to 10 g/m 2 or up to 15 g/m 2 .
• the layer thickness of the individual streams of material in the curtain or their application weight (dry) on the substrate can be the same or different.
• the coat weight of an outer layer is less than that of an inner layer of the curtain and may be 0.3 g/m 2 to 5 g/m 2 , but preferably 0.3 g/m 2 to 3 g/m 2 .
• the tenside content in the packaging material can be further reduced.
• the static viscosity of a stream in the curtain can be up to 3 Pa.s, preferably 50 to 500 mPa.s, measured with a Brookfield RVT rotational viscometer at 25° C. and a spindle speed of 20 and 100 rpm.
• the surface tensions of the two outer layers can be at least 5 mN/m lower than that of the adjacent inner layer of the curtain.
• the solids content of the layers of the curtain can be 5 to 50% by weight, preferably 10 to 30% by weight, based on the mass of the layer.
• Functional layers that are applied to the paper according to the invention are those with a barrier effect for, for example, water vapor, air, fat, oils and gas or a heat-seal layer.
• each of the functional layers (material streams) applied according to the invention can be an outer layer or an inner layer in the curtain.
• a second heat-seal layer can also be arranged inside the curtain.
• a functional layer with barrier properties for water vapor can essentially contain or consist of a hydrophobic polymer or hydrophobic polymer mixture.
• a polymer can be a polyolefin.
• Preferred polyolefins are polyethylene (PE), polypropylene (PP) or mixtures of polyethylene and polypropylene.
• a moisture vapor barrier layer limits the moisture vapor transmission rate of the packaging material to 50 cm 3 /m 2 per 24 hours (23°C, 50% RH) at 1 atm and less. Two or more layers having moisture vapor barrier properties may also be present in the curtain for application to a substrate.
• Another functional layer can have barrier properties for grease and/or oil.
• a layer is preferably made of a polar polymer educated. Suitable polar polymers for this purpose are, for example, polyvinyl alcohol (PVOH) and ethylene vinyl alcohol (EVOH).
• PVOH polyvinyl alcohol
• EVOH ethylene vinyl alcohol
• KIT value of greaseproof packaging materials obtained according to the invention is at least KIT 5 (DIN 53116) and is preferably greater than KIT 8.
• a corresponding barrier layer can be applied to the substrate.
• Moisture barrier properties can be created by coatings containing polypropylene or polyamide. Polypropylene can be used with particular preference for this purpose.
• a gas barrier layer can also be applied to the substrate.
• Conventional polymers known for this purpose can be used for this purpose.
• the barrier layer against gases of the packaging material according to the invention is preferably formed from at least one thermoplastic polymer.
• the thermoplastic polymer can be selected from ethylene-vinyl alcohol copolymers (EVOH), an at least partially hydrolyzed polyvinyl acetate, polyvinylidene chloride (PVDC), vinylidene chloride copolymer, preferably with a proportion of vinylidene chloride of at least 80% by weight, based on the total weight of the vinylidene chloride -Copolymers, or a mixture of at least two of the aforementioned polymers.
• EVOH ethylene-vinyl alcohol copolymers
• PVDC polyvinylidene chloride
• vinylidene chloride copolymer preferably with a proportion of vinylidene chloride of at least 80% by weight, based on the total weight of the vinylidene
• the ethylene/vinyl alcohol copolymers (EVOH) used to produce the layer are obtained by complete or incomplete hydrolysis of corresponding ethylene/vinyl acetate copolymers (EVAc). Fully hydrolyzed ethylene/vinyl acetate copolymers with a degree of hydrolysis greater than or equal to 98% and an ethylene content of 0.01 to 80 mol%, preferably 1 to 50 mol%, based on the total weight of the ethylene/vinyl alcohol Copolymers used.
• a polyvinyl acetate which is at least partially hydrolyzed to produce the gas barrier layer is obtained by complete or incomplete hydrolysis of corresponding polyvinyl acetates.
• Particularly preferred at least partially hydrolyzed polyvinyl acetates used to produce the layer are fully hydrolyzed polyvinyl acetates (polyvinyl alcohols, PVOH) with a degree of hydrolysis greater than/equal to 98% and partially hydrolyzed polyvinyl acetates with a degree of hydrolysis of 75% to 98%.
• the gas barrier layer in particular if it is at least partially based on an ethylene-vinyl alcohol copolymer, can preferably be connected to a polyamide layer as a further layer in each case for protection against moisture.
• a barrier layer of the packaging material produced according to the invention preferably has a layer thickness of 1 ⁇ m to 30 ⁇ m, particularly preferably 1 ⁇ m to 20 ⁇ m, very particularly preferably 1 ⁇ m to 10 ⁇ m, in particular 1.5 to 7 ⁇ m. If the layer contributes to optimizing the mechanical properties of the packaging material according to the invention, it preferably has a layer thickness of 5 ⁇ m to 500 ⁇ m, particularly preferably 20 ⁇ m to 150 ⁇ m when used as a tubular bag or lid material, or 100 ⁇ m to 100 ⁇ m when used for containers, such as troughs 500 ⁇ m.
• a barrier layer of the packaging material according to the invention can contain biopolymers, as are described for the production of the heat-seal layer. A transparent blend of biopolymers and the other polymers or polyamides used to make the heat seal layer can be used.
• An oxygen barrier layer and a water vapor barrier layer are particularly preferably provided on a substrate as barrier layers.
• Each of these layers in the curtain can be an outer layer in contact with air or an inner layer sandwiched between two outer layers.
• one of the functional layers can be an optionally multilayer heat-sealing layer made of thermoplastic polymers, which is directed inward in the packaging material produced.
• Thermoplastic polymers for the heat-seal layer include olefin homo- and copolymers, homo- and/or copolyesters, transparent mixtures of at least two of the polymers mentioned and mixtures of at least two of the polymers mentioned but of limited compatibility.
• the heat-sealing layer can preferably consist of up to 100% by weight of biopolymers as the polymer component.
• the polymer can also be a copolymer of at least one olefin and at least one ⁇ , ⁇ -unsaturated, non-olefinic monomer with carboxyl groups, their salts or their esters, such as ethylene/vinyl acetate copolymers, and also copolymers of ethylene and esters of acrylic acid or methacrylic acid, Copolymers of ethylene and acrylic acid or methacrylic acid and/or salts thereof, preferably sodium or zinc salts. It is also possible to use mixtures of at least two of the polymers mentioned or mixtures of at least two of the polymers mentioned but which have limited compatibility.
• each of the layers of the multilayer packaging material according to the invention can be equipped with customary additives, preferably with at least one additive selected from antiblocking agents, lubricants, antistatic agents, dyes, inorganic fillers, antioxidants, UV stabilizers, UV absorbers or Oxygen absorbers, provided they do not belong to the surface-active substances (surfactants) described.
• customary additives preferably with at least one additive selected from antiblocking agents, lubricants, antistatic agents, dyes, inorganic fillers, antioxidants, UV stabilizers, UV absorbers or Oxygen absorbers, provided they do not belong to the surface-active substances (surfactants) described.
• At least one of the functional layers can contain a pigment.
• the pigment can be kaolin, calcined clay, talc, calcium carbonate, laminar nanoparticles, high aspect ratio clays, titanium dioxide, luster white, synthetic polymer pigment, zinc oxide, barium sulfate, gypsum, synthetic magadiite, silica, alumina trihydrate, mica and diatomaceous earth.
• the packaging material according to the invention can be a packaging for any foodstuff.
• the food can be solid, semi-solid or liquid. It can be packaging for cheese, sausage, ham, meat, poultry or poultry parts, baked goods, baking ingredients, snack foods such as chips or peanut flakes, nuts, kernels, confectionery, such as chocolate, candy, chewing gum, fish, seafood, a solid or liquid ready meal such as a pie, a fat spread such as butter and margarine, mayonnaise, mustard, ketchup, or a spice or spice mix.
• Paper, cardboard or a plastic film can be used as a substrate or carrier for one or more functional layers and/or one or more further layers.
• a cellulose-based paper, preferably web-shaped paper, is preferably used as the carrier material.
• Paper within the meaning of the invention is either base paper or coated base paper.
• raw paper here means an uncoated or understood surface-sized paper.
• a base paper can contain sizing agents such as alkylkentene dimers, fatty acids and/or fatty acid salts, epoxidized fatty acid amides, alkenyl or alkyl succinic anhydride, wet strength agents such as polyamine-polyamide-epichlorohydrin, dry strength agents such as anionic, cationic or amphoteric polyamides or cationic starches, optical brighteners, fillers, pigments , dyes, defoamers and other auxiliaries known in the paper industry.
• the base paper can be surface sized. Examples of suitable glues are polyvinyl alcohol or oxidized starch.
• the base paper can be made on a Fourdrinier or a Yankee paper machine (cylinder paper machine).
• the basis weight of the raw paper is preferably 20 to 350 g/m 2 .
• the base paper can be used in uncompacted or compressed (smoothed) form.
• Particularly suitable are base papers having a density of 0.8 to 1.2 g / cm 3, preferably 0.90 to 1.1 g / cm 3.
• bleached hardwood kraft pulp LLKP
• bleached softwood kraft pulp NKP
• bleached hardwood sulfite pulp LBSP
• bleached softwood sulfite pulp NBSP
• Pulp fibers obtained from waste paper can also be used.
• the cellulose fibers mentioned can also be used as a mixture and optionally contain proportions of other fibers, for example synthetic resin fibers.
• pulp fibers made from 100% hardwood pulp are preferably used.
• the average fiber length of the unbeaten pulp is preferably 0.6 mm to 0.85 mm (Kajaani measurement).
• the cellulose preferably has a lignin content of less than 0.05% by weight, in particular 0.01 to 0.03% by weight, based on the mass of the cellulose.
• Kaolins calcium carbonate in its natural forms such as limestone, marble or dolomite, precipitated calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, talc, silica, aluminum oxide and mixtures thereof for the raw paper can be used as fillers, for example.
• the paper layer can consist of a coated base paper. In the case of a coated base paper, there is at least one pigment-containing layer on at least one side of the base paper arranged.
• a metal oxide, silicate, carbonate, sulfide or sulfate can be used as the pigment.
• Pigments such as kaolins, talc, calcium carbonate and/or barium sulfate are particularly suitable.
• a pigment mixture consisting of the abovementioned calcium carbonate and kaolin can be used for the pigment-containing layer.
• the calcium carbonate/kaolin quantity ratio is preferably from 30:70 to 70:30.
• the binder/pigment ratio in the pigment-containing layer can be from 0.1 to 2.5, preferably from 0.2 to 1.5, but in particular from about 0.9 to 1.3. Any known water-soluble and/or water-dispersible binder can be used in the pigment-containing layer.
• film-forming starches such as thermally modified starches, in particular corn starches or hydroxypropylated starches, are particularly suitable for this purpose.
• the pigment-containing layer can be applied inline or offline using any of the application units customary in papermaking, the amount applied preferably being chosen such that after drying the application weight is 0.1 to 30 g/m 2 , in particular 1 to 20 g/m 2 . or according to a particularly preferred embodiment is 2 to 8 g/m 2 .
• the pigment-containing layer is applied using a size press or film press integrated within the paper machine.
• the paper layer is essentially based on renewable raw materials such as cellulose and cellulose derivatives.
• the paper and thus the substrate can have a basis weight of 20 g/m 2 to 350 g/m 2 .
• the multilayer packaging material according to the invention preferably has a total layer thickness of 40 ⁇ m to 1000 ⁇ m, particularly preferably 40 ⁇ m to 150 ⁇ m.
• 3 to 10 layers can be arranged on the substrate of the packaging material.
• 3 to 6 functional layers and/or other layers, as explained above, can be arranged on the substrate.
• the packaging material according to the invention can particularly preferably have four layers, five layers or six layers.
• the base paper was made from eucalyptus pulp.
• the pulp was ground as an approximately 5% strength by weight aqueous suspension (high-density stock) using a refiner to a degree of beating of 36° SR.
• the mean fiber length was 0.64 mm.
• the concentration of the cellulose fibers in the thin stock was 1% by weight, based on the mass of the cellulose suspension.
• Additives were added to the thinstock such as cationic starch at 0.4% by weight, as a neutral sizing agent alkyl ketene dimer (AKD) at 0.48% by weight, wet strength agent polyamine-polyamide-epichlorohydrin resin (Kymene ® ) in an amount of 0.36% by weight and a natural CaCO 3 in an amount of 10% by weight.
• the amounts given relate to the pulp mass.
• the thin stock the pH of which was adjusted to about 7.5, was transferred from the headbox to the wire of the paper machine, whereupon sheet formation took place with dewatering of the web in the wire section of the paper machine.
• the paper web was further dewatered to a water content of 60% by weight, based on the web weight. Further drying took place in the drying section of the paper machine with heated drying cylinders. A base paper with a basis weight of 160 g/m 2 and a moisture content of about 7% was produced.
• the base paper is coated on both sides with a coating composition made from a styrene acrylate binder, starch and a pigment mixture of calcium carbonate and kaolin with an application weight of 15 g/m 2 each, dried and then smoothed with a calender.
• a coating composition made from a styrene acrylate binder, starch and a pigment mixture of calcium carbonate and kaolin with an application weight of 15 g/m 2 each, dried and then smoothed with a calender.
• coated base paper is used for the subsequent coating using a curtain coater.
• a composition was applied to one side of the coated raw paper using a curtain coater, the components and composition of which are described below.
• the speed to be coated was the same Paper web at 120 m/min.
• the curtain coater applicator was equipped with edge guides lubricated with dripping water and a vacuum suction device to remove this edge smearing water at the lower end of the edge guide just above the coated paper edge.
• the height of the curtain was 125 mm and the width of the curtain was 260 mm.
• the web was dried after coating using a hot-air flotation dryer.
• the following formulations were prepared in appropriately equipped mixing tanks and have the properties listed in Table 1.
• the curtains in the examples described were constructed according to the configurations listed in Table 2. Information on the application quantity based on the weight of the entire packaging material and also on the individual layers of the curtain is also listed in Table 2.
• the table also contains the quality-relevant parameters of the resulting packaging material.
• the results of Table 2 show that the examples according to the invention manage with a small proportion of surface-active substances and the parameters relevant to process engineering are in the acceptable range.
• the surface tension of the outer layers used, which come into contact with the air, is at least 5 mN/m lower than that of the adjacent inner layer.
• the lower surface tension ensures a stable curtain, which is the basis for high-quality packaging materials.
• packaging papers according to the invention produced in the tests meet all the quality criteria customary in the market that are set for packaging in the food sector.
• the barrier properties against water vapor and oxygen, which can be significantly undercut for the examples according to the invention, should be mentioned here as examples.
• the surface tension of liquids is determined in accordance with the DIN EN ISO 19403-3 standard.
• Oxygen Permeation or Oxygen Transmission Rate (OTR)
• the test serves to determine the oxygen permeability (permeation of pure oxygen or oxygen gas mixtures, e.g. air) of plastic films and plastic hollow bodies (e.g. packaging containers, plastic pipes, etc.) and thus their suitability for packaging purposes as well for technical applications.
• the test is carried out in accordance with DIN 53380-3 and at a temperature of 23°C and a relative humidity of 50%.
• the test is used to determine the water vapor permeability of plastic films, plastic webs (sheets) and multi-layer structures with plastic content using an electrolysis sensor.
• the test is carried out according to EN ISO 15106-3.
• the grease resistance test commonly known as the kit test, was carried out in accordance with DIN 53116.
• the curtain stability limit test is carried out with the curtain holders in a vertical position without suction. It starts with the flow rate (D), which results in the desired dry application for a given casting width (B), machine speed, solids content and density of the recipe.
• flow cm 3 / at least broad m * speed m / at least * dry application G / m 2 * 100 % solids content % * density G / m 3
• the flow rate is then reduced in 5% steps, based on the mass of the stream, until the curtain collapses without any further external influence.
• the last set flow before the curtain collapse divided by the width of the curtain defines the curtain stability limit.
• a flow rate of 20% above the determined curtain stability limit is set.
• the curtain is then visually checked for curtain openers for 10 minutes and the number is documented.
• Viscosity is measured with a Brookfield RVT viscometer (available from Brookfield Engineering Laboratories, Inc., Stoughton, Massachusetts, USA). To determine the viscosity, 600 ml of a sample are poured into a 1000 ml beaker and the viscosity is measured at 25° C. at a spindle speed of 20 and 100 rpm.
• the basis weight was determined according to DIN EN ISO 536.

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• Wrappers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Laminated Bodies (AREA)

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Citations (9)

• 2020
  • 2020-07-20 EP EP20186744.7A patent/EP3943661A1/fr active Pending
• 2021
  • 2021-07-20 JP JP2021119954A patent/JP2022020609A/ja active Pending

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