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
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/10—Packing paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
• • 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
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
  • D21H17/24—Polysaccharides
  • D21H17/28—Starch
  • D21H17/29—Starch cationic
• • 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
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
• • 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
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/16—Sizing or water-repelling agents

Definitions

• the present invention relates to packaging paper for sharp-edged objects and/or objects that have unevenly arranged, protruding, essentially non-deformable elevations on at least one of its surfaces, which consists of kraft sulphate pulp as the main component and fillers, starch, sizing agents and other processing aids as well optionally bleaching agents and/or coating agents.
• Packaging materials made of paper and/or cardboard are used extensively worldwide for a wide variety of objects or materials, on the one hand to provide recyclable packaging materials and on the other hand to reduce or avoid as far as possible the amount of waste materials that do not decompose. For this reason, in recent years more and more paper has also been used in areas in which only a few years ago plastics and plastic composite materials were used as packaging material. possible fat and/or moisture content, the external shape of the packaged objects and the stability of the packaged objects in relation to pressure, temperature stress and the like. more consideration must be taken, so that it becomes necessary to provide specially manufactured or treated papers. So it is known to use paper for packaging building materials such as sand, cement or stones, as well as for packaging consumer goods, especially for food such as flour, rice, pasta, nuts and the like. More. Another area of use for paper is the packaging of consumer goods such as toys, clothing, electronic components, household goods, screws or nails and much more, as well as open packaging such as sacks or carrier bags.
• Packaging papers must meet the respective requirements of the goods to be packaged in them; in particular, they must have sufficient tear strength, elasticity, air permeability, and the like. On the other hand, it is, for example, for a packaging paper which is used for packaging moisture-sensitive materials is used, provided that it has sufficient moisture resistance and, in particular, has a barrier property to moisture or has only very limited moisture permeability.
• a person skilled in the art can estimate and determine which specific properties a packaging paper must have for the respective planned use , all paper that meets these requirements, take into account a large number of factors, which often also interact with one another, so that a final composition of the packaging paper and its production usually require many attempts and failed attempts.
• Paper can only be used here to a limited extent, since on the one hand it can be rubbed off on uneven areas and can lose a large part of its original positive properties, such as strength and the like, by destroying or tearing the structure of the paper.
• Another possible risk is that the packaging paper tears through contact with the sharp edges or points of the items packed in it and as a result the items packed in it can either be lost, damaged or degraded in quality, since an intact packaging is no longer possible present.
• packaging paper In order to avoid such a tearing of packaging paper, it has often been the case in the past that it was coated on at least one side with plastic films, polymers or other tear-resistant and at the same time elastic materials, or an insert made of such materials was inserted into multi-layer papers to paper to be able to use as packaging material for sharp-edged objects or objects with an uneven surface.
• packaging materials made of paper which on the one hand are sufficiently elastic, stretchable and flexible in order not to tear under the corresponding stresses and on the other hand if sharp-edged objects are contained therein packed, destruction or damage of the packaging, such as being able to prevent objects packed in it from being pierced, rubbed off or torn open.
• the present invention thus aims to provide such a packaging paper with which it is possible to package a wide variety of sharp-edged objects or materials having an irregular surface without the packaged object penetrating the packaging paper or tearing same comes.
• a packaging paper according to the invention is essentially characterized in that it contains at least 95% primary pulp, at least 80%, preferably at least 90%, in particular at least 95% pulp with an average length-weighted fiber length of at least 2.0 mm and less than 4 5%, preferably less than 4.0%, in particular less than 3.7% fillers and cationic starch and other processing aids, that it has an elongation at break in the machine direction (MD) according to ISO 1924-3:2005 of at least 6.0%, preferably at least 6.5% and that it has a puncture energy index according to DIN EN 14477:2004 measured at a test speed of 10.0 mm/min on any side of the packaging paper in the range from 30 to 75 mJ.m 2 /kg, preferably 35 up to 70 mJ.m 2 /kg.
• MD machine direction
• the packaging paper contains at least 95% primary cellulose ensures that the packaging paper is of the highest quality and best properties, as it is known to a person skilled in the art that the possible admixture of recycled cellulose can adversely affect the paper quality and in particular the strength properties and the elasticity properties of the paper can be impaired. Surprisingly, it has been shown that a possible admixture of secondary pulp in the order of up to a maximum of 5% does not adversely affect the strength and elasticity of the paper.
• the proportion of primary cellulose may need to be adjusted and, for example, increased.
• the packaging paper is designed in such a way that it contains 100% primary cellulose. Even if an admixture of secondary pulp in the order of up to a maximum of 5% does not adversely affect the strength and elasticity of the paper, the use of 100% primary pulp can ensure that the packaging paper for the packaging of has a non-uniform, uneven Surface having foods such as pasta, muesli bars, nuts or the like. Is suitable.
• packaging papers it is possible, depending on the grammage of the respective paper, to provide single- or multi-ply packaging papers, which can serve, for example, as a replacement for plastic packaging or packaging boxes.
• this term also includes the ash content that is in the paper itself. This is because the amounts of ash present in the paper do not normally exceed 0.5%.
• At least 80% softwood pulp, more preferably at least 90% softwood pulp, in particular at least 95% with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 2.1 mm and the remainder hardwood pulp with an average length-weighted fiber length according to ISO 16065 -2:2014 of at least 1.0 mm it is possible in particular to influence the strength and elasticity properties of the packaging paper produced with it in the direction of greater elasticity of the packaging paper and thereby prevent premature tearing of the packaging paper produced according to the invention when it comes into contact with sharp-edged objects in Contact comes to hold back.
• the paper auxiliaries such as the filler content, the cationic starch or the sizing agent, in particular to sizing agents processed at a neutral pH in the paper to values of less than 4.5%
• packaging paper made exclusively from primary pulp which not only has excellent mechanical properties, but is also suitable for special purposes, such as food packaging and the like, and is also used as such, in particular due to the small amounts of additional additives or fillers used may be.
• Such a packaging paper which consists essentially exclusively of primary pulp, which consists mainly of softwood fibers, which may contain or have mixed in small amounts of hardwood fibers, and contains small amounts of fillers and starch, is achieved by a special treatment, in particular, for example grinding of the cellulose fibers and optionally further process steps, such as treatment of the paper web on a Clupak system, a calender and the like. an elongation at break in the machine direction according to ISO 1924-3:2005 of at least 6.0%.
• suitable primary pulps include long-fiber pulp comprising one or more types of coniferous wood, short-fiber pulp comprising one or more types of hardwood, and mixtures comprising the pulps mentioned.
• the pulps are preferably produced according to the kraft sulphate process.
• Such packaging paper also has a puncture energy index according to DIN EN 14477:2004 measured at a test speed of 10.0 mm/min on any side of the packaging paper in the range from 30 to 75 mJ.m 2 /kg, which means that if such a paper is used for packaging sharp-edged objects and/or objects having irregularly arranged, protruding and substantially non-deformable bumps on at least one of their surfaces, penetration or piercing of the sharp-edged objects by the paper can be prevented.
• packaging paper with an elongation at break of more than 6.0% also has the highest values for the puncture energy index and can therefore have disadvantageous effects, which e.g.
• the packaging paper provides an optimally balanced paper, both in terms of elongation and strength.
• a wrapping paper according to the invention can now be used safely and without risk of loss of items packaged therein due to abrasion by protruding portions of the items packaged therein, for the packaging of such sharp-edged items as, for example, gravel, pellets, metal parts such as screws, clothes with buttons , shoes with sharp heels, children's toys, but also foods such as muesli bars, chocolate-nut bars, nuts, pasta and the like.
• Puncture energy which is defined in DIN EN 14477:2004, is the force, taking into account an elongation, that has to be applied in order to penetrate paper or cardboard with a defined test specimen.
• Puncture energy index which is the puncture energy of a paper divided by its grammage, was measured in connection with the present invention using the standard DIN EN 14477:2004, which standard is usually used to determine the puncture energy of flexible packaging materials such as plastic films.
• the elongation on puncture in mm is also decisive for ensuring that the packaging is not damaged.
• the integral under a force-strain curve reflects the energy that a material, and according to the present invention a packaging paper, can absorb without damaging the same.
• the puncture energy index in mJ.m 2 /kg is divided by the grammage according to ISO 536:2019 of the respective paper, converted into kg/m 2 .
• the puncture energy index is calculated in analogy to the calculation of the tensile work index according to ISO 1924-3:2005.
• an average length-weighted fiber length according to ISO 16065-2:2014 of the cellulose fiber is understood to mean a length-weighted average of the fiber lengths.
• a cationic starch means a starch which has been subjected to a cationization treatment with bases such as NaOH, KOH, calcium carbonate and a cationizing agent such as 2,3-epoxy-propyl-trimethylammonium chloride and the like Degree of cationization, i.e. having a fraction of cationic charge in the range of from 0.02 to about 0.06.
• Softwood pulp is understood to mean pulp which has been produced from softwood, ie wood with a Darr density of less than 0.55 g/cm 3 .
• softwoods are essentially almost all softwoods, such as spruce, larch, fir, pine and Douglas fir, but also hardwoods such as willow, poplar or lime.
• Hardwood pulp is understood to mean pulp which has been produced from hardwood, ie wood which has a Darr density of more than 0.55 g/m 3 .
• Representatives of hardwoods are, for example, beech, oak, ash, as well as birch, poplar, aspen, maple and acacia.
• Another distinguishing feature between hardwood and softwood is the fiber length of the fibers it contains, whereby this fiber length is influenced not only by the type of wood but also by the age of the tree and the position of the fiber in the cross-section of the log.
• essentially softwoods with a length-weighted average fiber length of at least 2.1 mm and optionally hardwoods with a length-weighted average fiber length of at least 1.0 mm are used.
• This length-weighted fiber length of a pulp fiber is defined in ISO 16065-2:2014 and is determined according to this standard.
• the packaging paper according to the invention is further developed in such a way that it is 100% Contains primary pulp. If it is ensured that, apart from primary cellulose, in particular no recycled cellulose is contained in the paper, a packaging paper with exactly reproducible properties can be obtained. Furthermore, packaging papers which consist exclusively of primary cellulose can be used as packaging paper for food.
• the packaging paper is essentially characterized in that the primary pulp consists of a mixture consisting of at least 80% softwood pulp, more preferably at least 90% softwood pulp, in particular at least 95% softwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 2.1 mm and remainder hardwood pulp with a mean length-weighted fiber length according to ISO 16065-2:2014 of at least 1.0 mm.
• the packaging paper By choosing the appropriate primary pulp or a corresponding mixture of primary pulps, it is not only possible to influence the properties of the packaging paper, such as its elongation at break and its puncture energy index, but also other properties that are essential for packaging paper, such as the strength of the paper, tensile strength of the same, air permeability, and the like.
• the packaging paper is designed in such a way that the primary pulp consists of 100% softwood pulp with an average length-weighted fiber length according to ISO 16065-2:2014 of at least 2.1 mm.
• the packaging paper which is made 100% from softwood pulp with an average length-weighted fiber length of at least 2.1 mm according to ISO 16065-2:2014, compared to paper that has hardwood components or is made exclusively from hardwood pulp are thinner, have good strength and are also printable, but on the other hand, for example, higher hardwood components make the paper even more uniform in the sheet structure and the achievable print quality can also be improved.
• the packaging paper according to the present invention advantageously has a basis weight according to ISO 536:2019 of 45 g/m 2 to 165 g/m 2 , preferably 50 g/m 2 to 160 g/m 2 . It has been shown in the course of tests that this wide range of basis weights can be ensured in particular by adjusting the fillers that are added to the cellulose pulp and the refining energy used. It has been shown, for example, that the content of cationic starch must be kept low when papers with basis weights in the range from 50 g/m 2 to 70 g/m 2 and a puncture energy index according to DIN EN 14477:2004 in the range from 30 mJ.m 2 /kg to 75 mJ.m 2 /kg are to be produced.
• the packaging paper is designed in such a way that it has a tensile strength index in the machine direction according to ISO 1924-3:2005 of between 60 Nm/g and 140 Nm/g.
• tensile strength indices can be achieved with the packaging papers according to the invention due to the low filler content in the paper, whereby care must be taken when using fillers in particular that, if the paper is intended for use in the food sector, they are also approved for this purpose.
• particular reference should be made to grain sizes in the micrometer and nanometer range.
• the choice of filler is less critical, but in order to achieve the desired tensile strength indices in the machine direction between 60 Nm/g and 140 Nm/g, the filler content should in principle be kept low.
• Derivatized starch preferably cationic starch, for example, can be mentioned as a further auxiliary substance for adjusting strength properties.
• attention must be paid to their suitability as input materials for the manufacture of food packaging paper.
• the packaging paper is designed in such a way that the primary cellulose is contained as ground, in particular high-consistency ground cellulose with a Schopper-Riegler freeness according to ISO 5267-1:1999 between 13°SR and 20°SR. Beating of pulp influences the fiber strength or firmness and thus raises the quality of the product made with it from several points of view. Especially when using non-bleached, i.e. unbleached (i.e.
• the paper quality can be influenced in such a way that the remaining wood splinters contained in the pulp and fiber agglomerates not broken up by the pulp cooking are finely ground during high-consistency grinding and the texture of the paper is thus better evened out and in particular is smoothed.
• the primary pulp used is a ground, in particular high-consistency ground pulp with a Schopper-Riegler freeness according to ISO 5267-1:1999 after high-consistency grinding between 13°SR and 20°SR, it is possible to further increase the puncture energy.
• the cellulose can of course also be ground to a low consistency. Low-consistency grinding is carried out at a pulp suspension consistency of between 2% and 6%, with this step being able to achieve a further increase in strength and thus also an increase in the puncture energy.
• the packaging paper can have a kappa number according to ISO 302:2015 between 35 and 58, preferably 39 and 48.
• the use of packaging paper with a kappa number according to ISO 302:2015 between 35 and 58, preferably 39 and 48 ensures that the use of bleaching chemicals can be dispensed with and the use of the packaging paper in the food sector is therefore advantageous .
• an unbleached pulp can bind more starch than a bleached pulp fiber.
• the use of cationic starch increases the dry strength of the paper mixed with it, which is why, particularly when using unbleached pulp for the production of packaging paper, the aim is to use starch contents of more than 12 kg/ton of paper atro (atro means absolutely dry).
• Bleaching paper removes by-products and is used in particular when the surface of the paper has to be printed, for example, since bleached paper is usually easier to print on because better printing color brilliance is possible.
• the packaging paper is primarily used as unbleached packaging paper, for the production of which pulps with kappa numbers according to ISO 302:2015 in the range of 35 or higher have been used.
• packaging paper With regard to the objects packed in it, packaging paper must on the one hand be dense enough to avoid loss of powdery materials or to reduce water absorption of hygroscopic objects packed in it according to the application and on the other hand have sufficient air permeability so that air brought in during filling, for example, can also pass through the packaging paper itself can escape.
• the packaging paper has a Gurley value according to ISO 5636-5:2013 between 5 s and 45 s, in particular 10 s and 40 s.
• the packaging paper can be designed according to a development in such a way that at least one side of the packaging paper is surface-coated, in particular smoothed and/or coated.
• the moisture barrier property can be influenced, for example, but the puncture energy in particular can also be further improved, so that the paper can withstand even greater stresses, in particular in relation to uneven or pointed objects packed in the paper.
• the packaging paper is designed in such a way that the puncture energy index according to DIN EN 14477:2004 between a surface-coated side of the packaging paper and an untreated side of the packaging paper is greater by a factor of 1.0 to 1.7 or less than 1 by a factor 0 to 1.7 differs.
• the puncture energy index is usually influenced by the implementation of surface treatment steps such as the introduction of functional barrier coatings.
• the puncture energy index is preferably to be seen as an inherent paper property and is not or only to a small extent dependent on the surface finish.
• Appropriate surface treatment is particularly advantageous and useful if one side of the paper comes into contact with sharp-edged objects and the other side is to be printed or written on, for example, in which case the two surfaces of the wrapping paper must be subjected to different tempering treatments.
• Example 1 Production of packaging paper with a grammage of 50 g/m 2 Process description:
• An unbleached pulp consisting of 95% primary softwood pulp with a kappa number of 42 and 5% primary hardwood pulp with a kappa number of 40, which is first subjected to high-consistency beating with a beating capacity of 190 to 210 kWh/to, where a degree of freeness of the pulp after high-consistency beating was 17°SR and then this pulp was subjected to low-consistency beating with a beating capacity of 75 kWh/ton until a degree of freeness of at least 18°SR was reached.
• the additives are added in the approach flow of the paper machine.
• the pH was adjusted to a pH of 6.5 to 7.5 with aluminum sulfate, cationic starch, with a degree of cationization DS of 0.05, was added in an amount of 2.5 kg/ton paper atro and as Size used was alkenylsuccinic anhydride in an amount of 0.5 kg/tonne of dry paper.
• the pulp contained no fillers.
• the consistency of the pulp at the headbox was 0.2%.
• Dewatering took place on a Fourdrinier wire section, and with a press section with three nips, the line pressure at the three nips being 55 kN/m, 80 kN/m and 80 kN/m. Before the still damp paper was fed to the Clupak system, it was pre-dried in a slalom dryer section and treated in a Clupak system with a differential speed of -4.8% and finally finally dried.
• the paper can be used as such and the paper properties described in the table below were measured with this paper.
• the paper can additionally be calendered, for example in a soft nip or long nip calender, or subjected to a coating treatment, such as a dispersion coating treatment, whereby the properties can be further changed.
• a calendering treatment is carried out on the packaging paper when this has a dry content of at least 88%, preferably at least 90%, particularly preferably at least 91%, ie the residual moisture content is less than 12%.
• such packaging paper can be used, for example, as a replacement for thin plastic packaging, for example for food such as muesli bars.
• the paper thus produced had the following properties: paper property standard Unit Direction result grammage ISO 536:2019 gsm 2 49 tensile strenght ISO1924-3:2005 kN/m md 5.8 Tensile Strength Index ISO1924-3:2005 Nm/g md 118.4 tensile strenght ISO1924-3:2005 kN/m CD 2.4 Tensile Strength Index ISO1924-3:2005 Nm/g CD 49.0 elongation at break ISO1924-3:2005 % md 7.1 elongation at break ISO1924-3:2005 % CD 8.8 tensile work ISO1924-3:2005 J/ m2 md 261 train breaking work ISO1924-3:2005 J/ m2 CD 162 Air Permeability Gurley ISO 5636-5:2013 s 22.7 Bendtsen roughness ISO8791-2:2013 ml/min top 1170 Bendtsen roughness ISO8791-2:2013 ml/min bottom 740 puncture resistance DIN EN 14477:2004
• Example 2 Production of a packaging paper with a grammage of 100 g/m 2 Process description:
• An unbleached pulp consisting of 100% primary pulp from softwood with a kappa number of 42 was first subjected to high-consistency beating with a beating capacity of 220 to 240 kWh/ton, with a freeness of the pulp after high-consistency beating being 17°SR and then this was Pulp subjected to low-consistency beating with a beating capacity of 80 to 90 kWh/ton until a freeness of at least 18°SR was reached.
• the auxiliary materials were added in the approach flow of the paper machine.
• the pH was adjusted to a value of 6.8 to 7.3 with aluminum sulphate, cationic starch, with a degree of cationization DS of 0.03, was metered in in an amount of 14 kg/ton paper atro and as a size alkenylsuccinic anhydrides were used in an amount of 0.8 kg/to of dry paper.
• fillers were added in an amount of 0.3 kg/ton paper dry. The consistency of the pulp at the headbox was 0.25%.
• Dewatering was carried out on a Foudrinier wire section and with a press section with three nips, one of which may be a shoe press, the line pressure on the three nips being 60 kN/m, 90 kN/m and 500 kN/m respectively (in the shoe press ) fraud.
• the Clupak line Before the still damp paper was fed to the Clupak line, it was subjected to contact drying, conventional drying and hot air use at 169 °C, then pre-dried in a slalom dryer section and treated in a Clupak line with a differential speed of -7.9% and finally final dried.
• the paper can be used as such and the paper properties described in the table below were measured with this paper.
• the paper can also be calendered, for example in a soft nip or long nip calender, or subjected to a coating treatment, such as a dispersion coating treatment, whereby the properties can be changed even further.
• a coating treatment such as a dispersion coating treatment
• Such packaging paper can be used, for example, with or without an additional coating, for the production of paper sacks, for example for packaging gravel or game pieces.
• the paper thus produced had the following properties: paper property standard Unit Direction result grammage ISO 536:2019 gsm 2 101 tensile strenght ISO1924-3:2005 kN/m md 8.4 Tensile Strength Index ISO1924-3:2005 Nm/g md 83.5 tensile strenght ISO1924-3:2005 kN/m CD 6.4 Tensile Strength Index ISO1924-3:2005 Nm/g CD 63.2 elongation at break ISO1924-3:2005 % md 9.4 elongation at break ISO1924-3:2005 % CD 9.5 train breaking work ISO1924-3:2005 J/ m2 md 412 tensile work ISO1924-3:2005 J/ m2 CD 382 Air Permeability Gurley ISO 5636-5:2013 s 16.9 Bendtsen roughness ISO8791-2:2013 ml/min top 1310 Bendtsen roughness ISO8791-2:2013 ml/min bottom 1650 puncture resistance DIN EN 14477:2004 with 10
• Example 3 Production of a packaging paper with a grammage of 130 g/m 2 Process description:
• An unbleached pulp consisting of 100% primary pulp from softwood with a kappa number of 41 was first subjected to high-consistency beating with a beating capacity of 220 to 240 kWh/ton, with a freeness of the pulp after high-consistency beating being 18°SR and then this was Pulp subjected to low-consistency beating with a beating capacity of 80 to 90 kWh/ton until a freeness of at least 19°SR was reached.
• the auxiliary materials were added in the approach flow of the paper machine.
• the pH was adjusted to a value of 6.7 to 7.3 with aluminum sulphate, cationic starch, with a degree of cationization DS of 0.03, was metered in in an amount of 14 kg/ton paper atro and as a size alkenylsuccinic anhydrides were used in an amount of 0.8 kg/to of dry paper. Furthermore, no fillers were added. The consistency of the pulp at the headbox was 0.25%. Dewatering was carried out on a Foudrinier wire section and with a press section with three nips, one of which can be a shoe press, the line pressure on the three nips being 60 kN/m, 90 kN/m and 500 kN/m (in the shoe press) fraud.
• the paper can be used as such and the paper properties described in the table below were measured with this paper.
• the paper can also be calendered, for example in a soft nip or long nip calender, or subjected to a coating treatment, such as a dispersion coating treatment, whereby the properties can be changed even further.
• a coating treatment such as a dispersion coating treatment
• Such packaging paper can be in the form of multi-layer packaging paper, with or without an additional coating, and can be used as a replacement for cardboard packaging, e.g. for foodstuffs such as rice.
• the paper thus produced had the following properties: paper property standard Unit Direction result grammage ISO 536:2019 gsm 2 131 tensile strenght ISO1924-3:2005 kN/m md 10.3 Tensile Strength Index ISO1924-3:2005 Nm/g md 78.6 tensile strenght ISO1924-3:2005 kN/m CD 8.2 Tensile Strength Index ISO1924-3:2005 Nm/g CD 62.6 elongation at break ISO1924-3:2005 % md 10.3 elongation at break ISO1924-3:2005 % CD 9.7 train breaking work ISO1924-3:2005 J/ m2 md 566 tensile work ISO1924-3:2005 J/ m2 CD 497 Air Permeability Gurley ISO 5636-5:2013 s 28.6 Bendtsen roughness ISO8791-2:2013 ml/min top 1420 Bendtsen roughness ISO8791-2:2013 ml/min bottom 1890 puncture resistance DIN EN 14477:
• Example 4 Production of a packaging paper with a grammage of 160 g/m 2 Process description:
• An unbleached pulp consisting of 100% primary pulp from softwood with a kappa number of 41 was first subjected to high-consistency beating with a beating capacity of 240 to 250 kWh/ton, with a degree of beating of the pulp after high-consistency beating was 17°SR and was subsequently this pulp is subjected to low-consistency beating with a beating capacity of 45 to 55 kWh/ton until a degree of beating of at least 18°SR has been reached.
• the auxiliary materials were metered into the approach flow of the paper machine.
• the pH was adjusted to a value of 6.6 to 7.2 with aluminum sulphate, cationic starch, with a degree of cationization DS of 0.05, was metered in in an amount of 7.3 kg/ton paper atro and alkenylsuccinic anhydrides were used as sizing agents in an amount of 0.3 kg/ton paper dry. Furthermore, no fillers were added in an amount of 0.5 kg/to of dry paper. The consistency of the pulp at the headbox was 0.20%. Dewatering was carried out on a Fourdrinier wire section, such as a three-nip press section, the line pressure at the three nips being 60 kN/m, 90 kN/m and 80 kN/m. Before the still damp paper was fed into the Clupak system, it was subjected to contact drying, convection drying and hot air use at 165 °C and treated in a Clupak system with a differential speed of -10.9% and finally dried.
• a Fourdrinier wire section such
• the paper can be used as such and the paper properties described in the table below were measured with this paper.
• the paper can also be calendered, for example in a soft nip or long nip calender, or subjected to a coating treatment, such as a dispersion coating treatment, whereby the properties can be changed even further.
• the paper can also be used, for example, as multi-ply packaging paper, for example as a replacement for cardboard packaging.
• the paper thus produced had the following properties: paper property standard Unit Direction result grammage ISO 536:2019 gsm 2 160 tensile strenght ISO1924-3:2005 kN/m md 18.7 Tensile Strength Index ISO1924-3:2005 Nm/g md 116.9 tensile strenght ISO1924-3:2005 kN/m CD 7.9 Tensile Strength Index ISO1924-3:2005 Nm/g CD 49.4 elongation at break ISO1924-3:2005 % md 13.1 elongation at break ISO1924-3:2005 % CD 9.3 tensile work ISO1924-3:2005 J/ m2 md 1140 train breaking work ISO1924-3:2005 J/ m2 CD 520 Air Permeability Gurley ISO 5636-5:2013 s 31.2 Bendtsen roughness ISO8791-2:2013 ml/min top 4980 Bendtsen roughness ISO8791-2:2013 ml/min bottom 4420 puncture resistance DIN EN 14477:2004

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• 2021
  • 2021-03-31 EP EP21166361.2A patent/EP4067568A1/fr active Pending
• 2022
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  • 2022-03-30 CA CA3214122A patent/CA3214122A1/fr active Pending
  • 2022-03-30 WO PCT/EP2022/058495 patent/WO2022207756A1/fr active Application Filing
  • 2022-03-30 CN CN202280025336.6A patent/CN117321263A/zh active Pending

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