EP4202119A1 - Reclable paper of high wet strength - Google Patents
Reclable paper of high wet strength Download PDFInfo
- Publication number
- EP4202119A1 EP4202119A1 EP21217014.6A EP21217014A EP4202119A1 EP 4202119 A1 EP4202119 A1 EP 4202119A1 EP 21217014 A EP21217014 A EP 21217014A EP 4202119 A1 EP4202119 A1 EP 4202119A1
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- EP
- European Patent Office
- Prior art keywords
- paper
- tonne
- dry
- pam
- tonne dry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 239000011347 resin Substances 0.000 claims abstract description 15
- 229920005989 resin Polymers 0.000 claims abstract description 15
- BRLQWZUYTZBJKN-UHFFFAOYSA-N Epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 claims abstract description 5
- 150000001408 amides Chemical class 0.000 claims abstract description 5
- 229920002401 polyacrylamide Polymers 0.000 claims abstract description 5
- 239000000123 paper Substances 0.000 claims description 82
- 229920002472 Starch Polymers 0.000 claims description 12
- 239000008107 starch Substances 0.000 claims description 12
- 235000019698 starch Nutrition 0.000 claims description 12
- 239000011436 cob Substances 0.000 claims description 8
- 239000002655 kraft paper Substances 0.000 claims description 7
- 239000011122 softwood Substances 0.000 claims description 6
- 125000002091 cationic group Chemical group 0.000 claims description 5
- 239000011121 hardwood Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- 238000009736 wetting Methods 0.000 description 6
- 239000000835 fiber Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000008399 tap water Substances 0.000 description 4
- 235000020679 tap water Nutrition 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 235000013305 food Nutrition 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 1
- 235000002595 Solanum tuberosum Nutrition 0.000 description 1
- 244000061456 Solanum tuberosum Species 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229940037003 alum Drugs 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 230000001815 facial effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 1
- 235000013311 vegetables Nutrition 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- 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
- D21H17/33—Synthetic macromolecular compounds
- D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
- D21H17/375—Poly(meth)acrylamide
-
- 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
-
- 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
- D21H17/33—Synthetic macromolecular compounds
- D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/52—Epoxy resins
-
- 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
- D21H17/33—Synthetic macromolecular compounds
- D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
- D21H17/55—Polyamides; Polyaminoamides; Polyester-amides
-
- 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
- D21H17/33—Synthetic macromolecular compounds
- D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
- D21H17/56—Polyamines; Polyimines; Polyester-imides
-
- 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
- D21H21/18—Reinforcing agents
-
- 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
- D21H21/18—Reinforcing agents
- D21H21/20—Wet strength agents
-
- 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
Definitions
- the present disclosure relates to the field of paper and in particular recyclable paper having relatively high wet strength.
- An objective of the present disclosure is to provide a paper of relatively high wet strength that is recyclable.
- the present disclosure provides a paper (preferably a kraft paper) comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM), wherein the amount of PAE resin is 0.15-1.75 kg/tonne dry paper.
- PAE polyamino amide epichlorohydrin
- G-PAM glyoxylated polyacrylamide
- a paper comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM).
- PAE polyamino amide epichlorohydrin
- G-PAM glyoxylated polyacrylamide
- the amount of G-PAM is preferably 0.5-6.0 kg/tonne dry paper and more preferably 1.0-5.0 kg/tonne dry paper, such as 1.5-4.0 kg/tonne dry paper.
- the amount of PAE resin is preferably 0.25-1.50 kg/tonne dry paper, more preferably 0.30-1.25 kg/tonne dry paper, such as 0.30-1.10 kg/tonne dry paper or 0.40-1.25 kg/tonne dry paper.
- the PAE resin and the G-PAM is typically added in the wet end.
- the PAE resin and the G-PAM are thus wet end chemicals.
- the paper is preferably a kraft paper, such as a machine glazed (MG) kraft paper.
- MG machine glazed
- the paper may be bleached or unbleached. Bleached paper is typically easier to repulp and may therefore be preferred.
- the grammage of the paper is typically 35-200 g/m 2 and preferably 50-140 g/m 2 . In one embodiment, the grammage is 50-110 g/m 2 . In another embodiment, the grammage is 60-120 g/m 2 . In yet another embodiment, the grammage is 35-55 g/m 2 . In the present disclosure, grammage is measured according to ISO 536:2019.
- the teachings of the present disclosure are not intended for tissue paper, such as bath, towel, facial or napkin paper. Accordingly, the paper of the present disclosure typically has a density of at least 600 kg/m 3 , such as 600-1000 kg/m 3 . In the present disclosure, density is measured according to ISO 534:2011.
- the water absorbency of the paper is preferably relatively low.
- the Cobb 60 s value of at least one side of the paper is preferably below 40 g/m 2 , more preferably below 30 g/m 2 , such as below 25 g/m 2 .
- both sides of the paper have a Cobb 60 s value below 40 g/m 2 , such as below 30 g/m 2 , such as below 25 g/m 2 .
- Cobb 60 s is measured according to ISO 535:2014.
- hydrophobic size may be added, typically in the wet end of the paper machine.
- hydrophobic size are AKD, ASA and rosin size.
- the (dry) geometrical tensile index measured according to ISO 1924-3:2005 is at least 50 Nm/g, such as 50-150 Nm/g.
- the geometrical wet tensile index measured according to ISO 1924-3:2005 (using a wetting time of 10 min) of the paper is typically at least 10 Nm/g, such as at least 15 Nm/g, such as at least 16 Nm/g.
- the paper is preferably formed from a softwood pulp or a mixture of a softwood pulp and a hardwood pulp. Softwood pulp typically provides better strength and hardwood typically provides better surface properties.
- At least 75% by dry weight of the fibres of the paper are virgin fibres and preferably at least 90% by dry weight of the fibres of the paper are virgin fibres.
- Virgin fibres provide better strength than recycled fibres.
- the paper of the present disclosure comprises less than 3.5 kg/tonne dry paper of starch, such as 1-3 kg/tonne dry paper of starch.
- the starch is preferably cationic starch.
- Strength may be impaired by the addition of inorganic filler to the paper pulp.
- a high amount of filler corresponds to a high ash content.
- the paper of the present disclosure preferably has an ash content of less than 7.0% by dry weight, such as less than 5.5% by dry weight.
- the package is a Quick Service Restaurant food package.
- the package is typically a bag or a wrap.
- the package is a medical device package, in particular a medical device package that will undergo or has undergone gas or steam sterilization.
- the package may be a sack, such as a potato sack or a sack for a hydraulic binder (e.g. a cement sack), a garbage bag, a pouch for foods (e.g. fruits or vegetables) or an e-commerce bag.
- the grammage of the paper is typically in the range of 35-55 g/m 2 .
- a coated barrier paper comprising a paper substrate, which is a paper according to the first aspect, and a barrier coating provided on the paper substrate.
- Step Additive Fibre consist. (g/l) Dosage (g/kg dry fibre) Stirring time (s) 1 Fibre 12.5 2 PAE 12.5 Acc. to Table 2 30 3 AKD 12.5 30 4 G-PAM 12.5 Acc.
- the sheets were cured at 105 °C for 2 * 30 minutes.
- sheets were tested for the following properties: dry tensile strength (ten stripes per series in MD and seven stripes per series in CD except for series 2 for which only two stripes could be tested due to restricted amount of paper); COBB 60 s; air resistance (Gurley); and wet tensile strength measured after wetting times of 1, 3, 5, and 15 minutes (ten stripes per series in MD and seven stripes per series in CD except for series 2 for which only two stripes could be tested due to restricted amount of paper).
- Tensile index values were calculated by dividing the tensile strength values by the grammage. Geometrical tensile index values were calculated as the geometrical mean of the tensile index in MD and the tensile index in CD.
- WS 3 means average geometrical wet tensile strength index measured after 3 minutes of wetting time.
- WS 5 means average geometrical wet tensile strength index measured after 5 minutes of wetting time.
- WS 15 means average geometrical wet tensile strength index measured after 15 minutes of wetting time.
- FIG. 1 shows a sharp increase in the wet strength when 0.5 kg/tonne and 1.0 kg/tonne PAE is added, but a more modest increase when the amount is higher.
- figure 2 shows a relatively modest decrease of the recyclability when 0.5 kg/tonne and 1.0 kg/tonne PAE is added, and a sharper decrease beyond those amounts. Consequently, figures 1 and 2 together show that the optimal amount of PAE is from about 0.25 kg/tonne to about 1.5 kg/tonne when high wet strength is to be combined with high recyclability, provided that G-PAM has been added.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Paper (AREA)
Abstract
There is provided a paper comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM), wherein the amount of PAE resin is 0.15-1.75 kg/tonne dry paper.
Description
- The present disclosure relates to the field of paper and in particular recyclable paper having relatively high wet strength.
- Paper for some applications must retain some strength also if wetted. Hence, various "wet-strength agents" have been developed for papermaking. A common drawback of the use of such wet-strength agents is that it is difficult to repulp and hence recycle the paper.
- An objective of the present disclosure is to provide a paper of relatively high wet strength that is recyclable.
- Accordingly, the present disclosure provides a paper (preferably a kraft paper) comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM), wherein the amount of PAE resin is 0.15-1.75 kg/tonne dry paper.
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Figure 1 shows the geometrical wet tensile strength index (Nm/g) measured after 3 or 15 minutes of wetting time for paper sheets comprising different amounts (kg/tonne) of PAE resin. -
Figure 2 shows the recyclability (%) according to PTS Method PTS-RH 021/97 for paper sheets comprising different amounts (kg/tonne) of PAE resin. - Further details of the paper sheets are given in the Examples section below.
- As a first aspect of the present disclosure, there is provided a paper comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM). The amount of PAE resin is 0.15-1.75 kg/tonne dry paper.
- The amount of G-PAM is preferably 0.5-6.0 kg/tonne dry paper and more preferably 1.0-5.0 kg/tonne dry paper, such as 1.5-4.0 kg/tonne dry paper.
- The amount of PAE resin is preferably 0.25-1.50 kg/tonne dry paper, more preferably 0.30-1.25 kg/tonne dry paper, such as 0.30-1.10 kg/tonne dry paper or 0.40-1.25 kg/tonne dry paper.
- The paper of any one of the preceding claims, wherein said G-PAM is cationic G-PAM.
- In the papermaking, the PAE resin and the G-PAM is typically added in the wet end. The PAE resin and the G-PAM are thus wet end chemicals.
- The paper is preferably a kraft paper, such as a machine glazed (MG) kraft paper.
- The paper may be bleached or unbleached. Bleached paper is typically easier to repulp and may therefore be preferred.
- The grammage of the paper is typically 35-200 g/m2 and preferably 50-140 g/m2. In one embodiment, the grammage is 50-110 g/m2. In another embodiment, the grammage is 60-120 g/m2. In yet another embodiment, the grammage is 35-55 g/m2. In the present disclosure, grammage is measured according to ISO 536:2019.
- The teachings of the present disclosure are not intended for tissue paper, such as bath, towel, facial or napkin paper. Accordingly, the paper of the present disclosure typically has a density of at least 600 kg/m3, such as 600-1000 kg/m3. In the present disclosure, density is measured according to ISO 534:2011.
- To improve the performance in wet conditions, the water absorbency of the paper is preferably relatively low. Hence the Cobb 60 s value of at least one side of the paper is preferably below 40 g/m2, more preferably below 30 g/m2, such as below 25 g/m2. In one embodiment, both sides of the paper have a Cobb 60 s value below 40 g/m2, such as below 30 g/m2, such as below 25 g/m2. In the present disclosure, Cobb 60 s is measured according to ISO 535:2014.
- To obtain a relatively low Cobb 60 s value, hydrophobic size may be added, typically in the wet end of the paper machine. Examples of hydrophobic size are AKD, ASA and rosin size.
- Typically, not only the wet tensile strength, but also the dry tensile strength is of interest in the application in which the paper is used. In one embodiment, the (dry) geometrical tensile index measured according to ISO 1924-3:2005 is at least 50 Nm/g, such as 50-150 Nm/g.
- The geometrical wet tensile index measured according to ISO 1924-3:2005 (using a wetting time of 10 min) of the paper is typically at least 10 Nm/g, such as at least 15 Nm/g, such as at least 16 Nm/g.
- The paper is preferably formed from a softwood pulp or a mixture of a softwood pulp and a hardwood pulp. Softwood pulp typically provides better strength and hardwood typically provides better surface properties.
- In one embodiment, at least 75% by dry weight of the fibres of the paper are virgin fibres and preferably at least 90% by dry weight of the fibres of the paper are virgin fibres. Virgin fibres provide better strength than recycled fibres.
- Starch is often added as a strength agent in papermaking. However, the above-mentioned addition of G-PAM allows for a relatively low amount of starch. In one embodiment, the paper of the present disclosure comprises less than 3.5 kg/tonne dry paper of starch, such as 1-3 kg/tonne dry paper of starch.
- The starch is preferably cationic starch.
- Strength may be impaired by the addition of inorganic filler to the paper pulp. A high amount of filler corresponds to a high ash content. The paper of the present disclosure preferably has an ash content of less than 7.0% by dry weight, such as less than 5.5% by dry weight.
- As a second aspect of the present disclosure there is provided a package comprising a paper according to the first aspect of the present disclosure. In one embodiment, the package is a Quick Service Restaurant food package. In this embodiment, the package is typically a bag or a wrap. In another embodiment, the package is a medical device package, in particular a medical device package that will undergo or has undergone gas or steam sterilization. Further, the package may be a sack, such as a potato sack or a sack for a hydraulic binder (e.g. a cement sack), a garbage bag, a pouch for foods (e.g. fruits or vegetables) or an e-commerce bag.
- In the Quick Service Restaurant food package, the grammage of the paper is typically in the range of 35-55 g/m2.
- As a third aspect of the present disclosure, there is provided a coated barrier paper comprising a paper substrate, which is a paper according to the first aspect, and a barrier coating provided on the paper substrate.
- Lab sheets were produced in a dynamic sheet former. The target grammage was 80 g/m2. The lab procedure started with the preparation of a fiber suspension, which was a mixture bleached softwood kraft pulp and bleached hardwood kraft pulp in a dry weight ratio of 70:30. Both pulps were taken from the production of MG paper in BillerudKorsnäs' mill in Skärblacka. The pulps were diluted with tap water to obtain a fibre consistency of 12.5 g/l and the pH was adjusted 8.0. Furnishes for sheet forming were then prepared according to Table 1.
Table 1. "PAE" was Kymene GHP20 from Solenis, which is a polyamino amide epichlorohydrin resin. "AKD" was FennoSize 364M from Kemira. "G-PAM" was Fennobond 3150E from Kemira, which is a cationic glyoxylated polyacrylamide. "Silica" was FennoSil 442 from Kemira. "Starch" was Solbond PC35 from Solenis which is a cationic starch with degree of substitution 35%. Step Additive Fibre consist. (g/l) Dosage (g/kg dry fibre) Stirring time (s) 1 Fibre 12.5 2 PAE 12.5 Acc. to Table 2 30 3 AKD 12.5 30 4 G-PAM 12.5 Acc. to Table 2 15 5 Tap water 5 15 5 Alum 5 4 Added with the tap water 5 Sulphuric acid 5 To obtain pH 6 Added with the tap water 6 Starch 5 Acc. to Table 2 20 7 Silica 5 0.25 10 Table 2. PAE (kg/tonne) G-PAM (kg/tonne) Starch (kg/ton) Series 13 0 4 Series 21 2.8 2 Series 30.5 2.8 2 Series 40 2.8 2 - Ten sheets per series were made. Pressing was carried out by two passes through a nip press (5 bar). Drying was carried out in a "STFI dryer" at 130 °C for 10 minutes.
- To simulate the curing that paper typically undergoes in the paper machine and after the paper machine, but before the paper is used by the customer, the sheets were cured at 105 °C for 2 * 30 minutes.
- After curing, sheets were tested for the following properties: dry tensile strength (ten stripes per series in MD and seven stripes per series in CD except for
series 2 for which only two stripes could be tested due to restricted amount of paper); COBB 60 s; air resistance (Gurley); and wet tensile strength measured after wetting times of 1, 3, 5, and 15 minutes (ten stripes per series in MD and seven stripes per series in CD except forseries 2 for which only two stripes could be tested due to restricted amount of paper). - Tensile index values were calculated by dividing the tensile strength values by the grammage. Geometrical tensile index values were calculated as the geometrical mean of the tensile index in MD and the tensile index in CD.
- Further, sheets were sent to Karlstad University for recyclability testing in accordance with PTS Method PTS-RH 021/97.
- Results of the tests are presented in the tables 3 and 4 below.
Table 3. "WS3" means average geometrical wet tensile strength index measured after 3 minutes of wetting time. "WS5" means average geometrical wet tensile strength index measured after 5 minutes of wetting time. "WS15" means average geometrical wet tensile strength index measured after 15 minutes of wetting time. Series PAE (kg/ tonne) G-PAM (kg/ tonne) Recyclability* (%) WS3 (Nm/g) WS5 (Nm/g) WS15 (Nm/g) 1 3.0 0 46,5 22.7 21.6 21.0 2 0 2.8 99.7 17.0 14.9 12.2 3 0.5 2.8 98.0 18.8 17.1 15.1 4 1.0 2.8 93.7 21.1 18.3 17.3 * Recyclability (%) means the percentage suitable for recycling or usable in papermaking. It corresponds to the total mass of the sample (50g oven-dry =̂ 100%) less the total reject. - The results of Table 3 are also presented in
figures 1 and 2 . Notably,figure 1 shows a sharp increase in the wet strength when 0.5 kg/tonne and 1.0 kg/tonne PAE is added, but a more modest increase when the amount is higher. Conversely,figure 2 shows a relatively modest decrease of the recyclability when 0.5 kg/tonne and 1.0 kg/tonne PAE is added, and a sharper decrease beyond those amounts. Consequently,figures 1 and 2 together show that the optimal amount of PAE is from about 0.25 kg/tonne to about 1.5 kg/tonne when high wet strength is to be combined with high recyclability, provided that G-PAM has been added. - Further properties of the sheets are presented in table 4 below.
- Table 4. Average values for Cobb, Gurley and dry strength. The tests behind the results in this table were carried out between the first and the second curing, i.e. after curing at 105 °C for 1 * 30 minutes.
Series PAE (kg/ tonne) G-PAM (kg/ tonne) Cobb 60s (g/m2) Gurley (s) Geometrical dry tensile strength index (Nm/g) 1 3.0 0 21.4 18.5 99.3 2 0 2.8 19.3 24.2 107.2 3 0.5 2.8 18.9 22.6 105.9 4 1.0 2.8 18.9 15.4 110.0
Claims (15)
- A paper comprising polyamino amide epichlorohydrin (PAE) resin and glyoxylated polyacrylamide (G-PAM), wherein the amount of PAE resin is 0.15-1.75 kg/tonne dry paper.
- The paper of claim 1, wherein the amount of G-PAM is 0.5-6.0 kg/tonne dry paper, preferably 1.0-5.0 kg/tonne dry paper, such as 1.5-4.0 kg/tonne dry paper.
- The paper of claim 1 or 2, wherein the amount of PAE resin is 0.25-1.50 kg/tonne dry paper, preferably 0.30-1.25 kg/tonne dry paper, such as 0.30-1.10 kg/tonne dry paper or 0.40-1.25 kg/tonne dry paper.
- The paper of any one of the preceding claims, wherein said G-PAM is cationic G-PAM.
- The paper of any one of the preceding claims, which is a kraft paper, such as a machine glazed (MG) kraft paper.
- The paper of any one of the preceding claims, which is bleached.
- The paper of any one of the preceding claims, wherein the grammage measured according to ISO 536:2019 is 35-200 g/m2, such as 50-200 g/m2, preferably 50-140 g/m2, such as 50-110 g/m2 or 60-120 g/m2.
- The paper of any one of the preceding claims, wherein the density measured according to ISO 534:2011 is at least 600 kg/m3, such as 600-1000 kg/m3.
- The paper of any one of the preceding claims, wherein the Cobb 60 s value measured according to ISO 535:2014 of at least one side of the paper is below 40 g/m2, preferably below 30 g/m2, such as below 25 g/m2.
- The paper of any one of the preceding claims, wherein the geometrical tensile index measured according to ISO 1924-3:2005 is at least 50 Nm/g, such as 50-150 Nm/g.
- The paper of any one of the preceding claims, wherein the geometrical wet tensile index measured according to ISO 1924-3:2005 is at least 10 Nm/g, such as at least 15 Nm/g, such as at least 16 Nm/g.
- The paper of any one of the preceding claims, which is formed from a softwood pulp or a mixture of a softwood pulp and a hardwood pulp.
- The paper of any one of the preceding claims, wherein at least 75% by dry weight of the fibres of the paper are virgin fibres and optionally wherein at least 90% by dry weight of the fibres of the paper are virgin fibres.
- The paper of any one of the preceding claims, wherein the paper comprises less than 3.5 kg/tonne dry paper of starch, such as 1-3 kg/tonne dry paper of starch.
- A package comprising a paper according to any one of the preceding claims.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21217014.6A EP4202119A1 (en) | 2021-12-22 | 2021-12-22 | Reclable paper of high wet strength |
PCT/EP2022/052384 WO2022167437A1 (en) | 2021-02-02 | 2022-02-02 | Papermaking method |
US18/274,678 US20240110337A1 (en) | 2021-02-02 | 2022-02-02 | Papermaking Method |
EP22703919.5A EP4288603A1 (en) | 2021-02-02 | 2022-02-02 | Papermaking method |
CA3205747A CA3205747A1 (en) | 2021-02-02 | 2022-02-02 | Papermaking method |
PCT/EP2022/087656 WO2023118535A1 (en) | 2021-12-22 | 2022-12-22 | Recyclable paper of high wet strength |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP21217014.6A EP4202119A1 (en) | 2021-12-22 | 2021-12-22 | Reclable paper of high wet strength |
Publications (1)
Publication Number | Publication Date |
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EP4202119A1 true EP4202119A1 (en) | 2023-06-28 |
Family
ID=79024963
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP21217014.6A Pending EP4202119A1 (en) | 2021-02-02 | 2021-12-22 | Reclable paper of high wet strength |
Country Status (2)
Country | Link |
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EP (1) | EP4202119A1 (en) |
WO (1) | WO2023118535A1 (en) |
Citations (9)
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US5427652A (en) * | 1994-02-04 | 1995-06-27 | The Mead Corporation | Repulpable wet strength paper |
WO1995021298A1 (en) * | 1994-02-04 | 1995-08-10 | The Mead Corporation | Repulpable wet strength paperboard |
EP0835957A2 (en) * | 1996-10-11 | 1998-04-15 | Fort James Corporation | A method of forming a paper web |
WO1999050500A1 (en) * | 1998-03-31 | 1999-10-07 | Callaway Corporation | Improving retention and drainage in alkaline fine paper |
WO2001077437A1 (en) * | 2000-04-06 | 2001-10-18 | Sca Hygiene Products Ab | Method of adsorption of cationic and anionic polymers on the surface of particles and paper or nonwoven product containing such particles |
US20100269995A1 (en) * | 2009-04-24 | 2010-10-28 | Eastman Chemical Company | Sulfopolyesters for paper strength and process |
WO2015075318A1 (en) * | 2013-11-22 | 2015-05-28 | Kemira Oyj | Method for increasing paper strength |
WO2016085836A1 (en) * | 2014-11-27 | 2016-06-02 | Ecolab Usa Inc. | Paper-making aid composition and process for increasing tensile strength of paper |
US20170314204A1 (en) * | 2016-02-16 | 2017-11-02 | Kemira Oyj | Method for producing paper |
-
2021
- 2021-12-22 EP EP21217014.6A patent/EP4202119A1/en active Pending
-
2022
- 2022-12-22 WO PCT/EP2022/087656 patent/WO2023118535A1/en unknown
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5427652A (en) * | 1994-02-04 | 1995-06-27 | The Mead Corporation | Repulpable wet strength paper |
WO1995021298A1 (en) * | 1994-02-04 | 1995-08-10 | The Mead Corporation | Repulpable wet strength paperboard |
EP0835957A2 (en) * | 1996-10-11 | 1998-04-15 | Fort James Corporation | A method of forming a paper web |
WO1999050500A1 (en) * | 1998-03-31 | 1999-10-07 | Callaway Corporation | Improving retention and drainage in alkaline fine paper |
WO2001077437A1 (en) * | 2000-04-06 | 2001-10-18 | Sca Hygiene Products Ab | Method of adsorption of cationic and anionic polymers on the surface of particles and paper or nonwoven product containing such particles |
US20100269995A1 (en) * | 2009-04-24 | 2010-10-28 | Eastman Chemical Company | Sulfopolyesters for paper strength and process |
WO2015075318A1 (en) * | 2013-11-22 | 2015-05-28 | Kemira Oyj | Method for increasing paper strength |
WO2016085836A1 (en) * | 2014-11-27 | 2016-06-02 | Ecolab Usa Inc. | Paper-making aid composition and process for increasing tensile strength of paper |
US20170314204A1 (en) * | 2016-02-16 | 2017-11-02 | Kemira Oyj | Method for producing paper |
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WO2023118535A1 (en) | 2023-06-29 |
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