NZ619657B2 - Creping methods using ph-modified creping adhesive compositions - Google Patents
Creping methods using ph-modified creping adhesive compositions Download PDFInfo
- Publication number
- NZ619657B2 NZ619657B2 NZ619657A NZ61965712A NZ619657B2 NZ 619657 B2 NZ619657 B2 NZ 619657B2 NZ 619657 A NZ619657 A NZ 619657A NZ 61965712 A NZ61965712 A NZ 61965712A NZ 619657 B2 NZ619657 B2 NZ 619657B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- creping
- adhesive
- dryer
- base formulation
- dryer surface
- Prior art date
Links
- 239000000853 adhesive Substances 0.000 title claims abstract description 268
- 230000001070 adhesive Effects 0.000 title claims abstract description 268
- 239000000203 mixture Substances 0.000 title claims abstract description 244
- 238000009472 formulation Methods 0.000 claims abstract description 101
- 229920000642 polymer Polymers 0.000 claims abstract description 84
- 239000000835 fiber Substances 0.000 claims abstract description 72
- 238000000576 coating method Methods 0.000 claims abstract description 71
- 239000011248 coating agent Substances 0.000 claims abstract description 70
- 239000003002 pH adjusting agent Substances 0.000 claims abstract description 44
- 238000004519 manufacturing process Methods 0.000 claims abstract description 12
- 239000002585 base Substances 0.000 claims description 96
- 238000000034 method Methods 0.000 claims description 73
- 239000007921 spray Substances 0.000 claims description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 26
- 238000002156 mixing Methods 0.000 claims description 24
- 230000001965 increased Effects 0.000 claims description 23
- 229910052751 metal Inorganic materials 0.000 claims description 18
- 239000002184 metal Substances 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 17
- 235000011180 diphosphates Nutrition 0.000 claims description 16
- XPPKVPWEQAFLFU-UHFFFAOYSA-J Pyrophosphate Chemical compound [O-]P([O-])(=O)OP([O-])([O-])=O XPPKVPWEQAFLFU-UHFFFAOYSA-J 0.000 claims description 14
- -1 alkali metal bicarbonate Chemical class 0.000 claims description 14
- 239000000463 material Substances 0.000 claims description 11
- 230000002378 acidificating Effects 0.000 claims description 10
- 239000003607 modifier Substances 0.000 claims description 10
- XSQUKJJJFZCRTK-UHFFFAOYSA-N urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-K [O-]P([O-])([O-])=O Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 7
- 125000002091 cationic group Chemical group 0.000 claims description 7
- 239000010452 phosphate Substances 0.000 claims description 7
- PRKQVKDSMLBJBJ-UHFFFAOYSA-N Ammonium carbonate Chemical compound N.N.OC(O)=O PRKQVKDSMLBJBJ-UHFFFAOYSA-N 0.000 claims description 6
- 150000008044 alkali metal hydroxides Chemical group 0.000 claims description 6
- 239000001099 ammonium carbonate Substances 0.000 claims description 6
- 239000004202 carbamide Substances 0.000 claims description 6
- VTZCXKGZGDSBQC-UHFFFAOYSA-J diazanium;zirconium(4+);dicarbonate;dihydroxide Chemical compound [NH4+].[NH4+].[OH-].[OH-].[Zr+4].[O-]C([O-])=O.[O-]C([O-])=O VTZCXKGZGDSBQC-UHFFFAOYSA-J 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- 229920003169 water-soluble polymer Polymers 0.000 claims description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate dianion Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxyl anion Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 5
- 239000011780 sodium chloride Substances 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
- 230000003139 buffering Effects 0.000 claims description 4
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 3
- 239000003513 alkali Substances 0.000 claims description 3
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 3
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 3
- 229910000272 alkali metal oxide Inorganic materials 0.000 claims description 3
- 229910000318 alkali metal phosphate Inorganic materials 0.000 claims description 3
- 229910052910 alkali metal silicate Inorganic materials 0.000 claims description 3
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 claims description 3
- 150000003973 alkyl amines Chemical class 0.000 claims description 3
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 3
- 235000012501 ammonium carbonate Nutrition 0.000 claims description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 3
- 239000000908 ammonium hydroxide Substances 0.000 claims description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 3
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 claims description 3
- 150000003242 quaternary ammonium salts Chemical class 0.000 claims description 3
- 150000003672 ureas Chemical class 0.000 claims description 3
- 229910001854 alkali hydroxide Inorganic materials 0.000 claims description 2
- 230000001264 neutralization Effects 0.000 claims description 2
- 150000007530 organic bases Chemical class 0.000 claims description 2
- 238000005507 spraying Methods 0.000 claims description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 abstract description 24
- 238000007792 addition Methods 0.000 abstract description 10
- 239000003795 chemical substances by application Substances 0.000 description 30
- 239000000123 paper Substances 0.000 description 29
- 230000004048 modification Effects 0.000 description 20
- 238000006011 modification reaction Methods 0.000 description 20
- 239000000047 product Substances 0.000 description 20
- 230000002829 reduced Effects 0.000 description 16
- 239000007787 solid Substances 0.000 description 15
- 210000001519 tissues Anatomy 0.000 description 15
- 238000004132 cross linking Methods 0.000 description 12
- 239000000654 additive Substances 0.000 description 10
- 229920005989 resin Polymers 0.000 description 10
- 239000011347 resin Substances 0.000 description 10
- 239000000126 substance Substances 0.000 description 9
- 239000004744 fabric Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- RYCLIXPGLDDLTM-UHFFFAOYSA-J tetrapotassium;phosphonato phosphate Chemical compound [K+].[K+].[K+].[K+].[O-]P([O-])(=O)OP([O-])([O-])=O RYCLIXPGLDDLTM-UHFFFAOYSA-J 0.000 description 8
- 239000003518 caustics Substances 0.000 description 7
- 239000006185 dispersion Substances 0.000 description 6
- 230000003028 elevating Effects 0.000 description 6
- FQENQNTWSFEDLI-UHFFFAOYSA-J Tetrasodium pyrophosphate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]P([O-])(=O)OP([O-])([O-])=O FQENQNTWSFEDLI-UHFFFAOYSA-J 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 230000000007 visual effect Effects 0.000 description 5
- 230000002411 adverse Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000002708 enhancing Effects 0.000 description 4
- 238000005755 formation reaction Methods 0.000 description 4
- 229920002451 polyvinyl alcohol Polymers 0.000 description 4
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 235000019818 tetrasodium diphosphate Nutrition 0.000 description 4
- LTMQZVLXCLQPCT-UHFFFAOYSA-N 1,1,6-trimethyltetralin Chemical compound C1CCC(C)(C)C=2C1=CC(C)=CC=2 LTMQZVLXCLQPCT-UHFFFAOYSA-N 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 3
- 229920001131 Pulp (paper) Polymers 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 239000003431 cross linking reagent Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229920001519 homopolymer Polymers 0.000 description 3
- 230000000670 limiting Effects 0.000 description 3
- 230000002441 reversible Effects 0.000 description 3
- 229920001187 thermosetting polymer Polymers 0.000 description 3
- LFVGISIMTYGQHF-UHFFFAOYSA-N Ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N HCl Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000006057 Non-nutritive feed additive Substances 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002250 absorbent Substances 0.000 description 2
- 230000002745 absorbent Effects 0.000 description 2
- ACOGMWBDRJJKNB-UHFFFAOYSA-N acetic acid;ethene Chemical group C=C.CC(O)=O ACOGMWBDRJJKNB-UHFFFAOYSA-N 0.000 description 2
- 239000002313 adhesive film Substances 0.000 description 2
- 238000007605 air drying Methods 0.000 description 2
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 2
- 229940027983 antiseptics and disinfectants Quaternary ammonium compounds Drugs 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-M bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 2
- 239000008199 coating composition Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 229920001038 ethylene copolymer Polymers 0.000 description 2
- 239000011121 hardwood Substances 0.000 description 2
- 239000002655 kraft paper Substances 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 235000019837 monoammonium phosphate Nutrition 0.000 description 2
- 239000006012 monoammonium phosphate Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 150000003856 quaternary ammonium compounds Chemical class 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 239000001488 sodium phosphate Substances 0.000 description 2
- 239000011122 softwood Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 238000007725 thermal activation Methods 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- JZNZSKXIEDHOBD-HUUCEWRRSA-N 2-[4,10-bis(carboxymethyl)-7-[(2R,3S)-1,3,4-trihydroxybutan-2-yl]-1,4,7,10-tetrazacyclododec-1-yl]acetic acid Chemical class OC[C@@H](O)[C@@H](CO)N1CCN(CC(O)=O)CCN(CC(O)=O)CCN(CC(O)=O)CC1 JZNZSKXIEDHOBD-HUUCEWRRSA-N 0.000 description 1
- 244000145845 Chattering Species 0.000 description 1
- ZBCBWPMODOFKDW-UHFFFAOYSA-N Diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 1
- 239000002879 Lewis base Substances 0.000 description 1
- 229910019440 Mg(OH) Inorganic materials 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Tris Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000000996 additive Effects 0.000 description 1
- 239000002671 adjuvant Substances 0.000 description 1
- 230000000240 adjuvant Effects 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 150000001447 alkali salts Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000007526 arrhenius bases Chemical class 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 230000000903 blocking Effects 0.000 description 1
- 150000007528 brønsted-lowry bases Chemical class 0.000 description 1
- UIIMBOGNXHQVGW-UHFFFAOYSA-M buffer Substances [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 1
- 239000006172 buffering agent Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 238000010192 crystallographic characterization Methods 0.000 description 1
- VOLSCWDWGMWXGO-UHFFFAOYSA-N cyclobuten-1-yl acetate Chemical compound CC(=O)OC1=CCC1 VOLSCWDWGMWXGO-UHFFFAOYSA-N 0.000 description 1
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 description 1
- 229910000397 disodium phosphate Inorganic materials 0.000 description 1
- 235000019800 disodium phosphate Nutrition 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- BRLQWZUYTZBJKN-UHFFFAOYSA-N epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 description 1
- HZAXFHJVJLSVMW-UHFFFAOYSA-N ethanolamine Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 230000001815 facial Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000002427 irreversible Effects 0.000 description 1
- 150000007527 lewis bases Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910000403 monosodium phosphate Inorganic materials 0.000 description 1
- 235000019799 monosodium phosphate Nutrition 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 230000001151 other effect Effects 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 230000021962 pH elevation Effects 0.000 description 1
- 238000001139 pH measurement Methods 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229920000962 poly(amidoamine) Polymers 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 239000011528 polyamide (building material) Substances 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 230000000717 retained Effects 0.000 description 1
- 150000003335 secondary amines Chemical class 0.000 description 1
- 239000002453 shampoo Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 235000002639 sodium chloride Nutrition 0.000 description 1
- AJPJDKMHJJGVTQ-UHFFFAOYSA-M sodium dihydrogen phosphate Chemical compound [Na+].OP(O)([O-])=O AJPJDKMHJJGVTQ-UHFFFAOYSA-M 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000000087 stabilizing Effects 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 230000000153 supplemental Effects 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 238000010345 tape casting Methods 0.000 description 1
- 150000003512 tertiary amines Chemical group 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004634 thermosetting polymer Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
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
- D21H19/00—Coated paper; Coating material
- D21H19/10—Coatings without pigments
- D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
- D21H19/16—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising curable or polymerisable compounds
-
- 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
- D21H21/146—Crêping adhesives
-
- 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
- D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
- D21H23/56—Rolls
- D21H23/58—Details thereof, e.g. surface characteristics, peripheral speed
- D21H23/60—Details thereof, e.g. surface characteristics, peripheral speed the material on the applicator roll being subjected to a particular treatment before applying to the paper
-
- 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
- D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
- D21H23/64—Addition to the formed paper by contacting paper with a device carrying the material the material being non-fluent at the moment of transfer, e.g. in form of preformed, at least partially hardened coating
Abstract
Disclosed herein is a method for manufacturing a creped fiber web comprising providing a rotating cylindrical dryer surface, providing a creping adhesive composition or coating package having a pH boosted at least 0.5 pH units relative to its original base formulation pH in the range of from about 4.5 to about 9 by the addition of a pH modifier such as sodium hydroxide in order to chemically set a crosslinkable polymer component at least in part before applying the creping adhesive composition to the rotating cylindrical dryer surface to provide an adhesive dryer surface on which a fiber web can be transferred, dried, and creped. .5 to about 9 by the addition of a pH modifier such as sodium hydroxide in order to chemically set a crosslinkable polymer component at least in part before applying the creping adhesive composition to the rotating cylindrical dryer surface to provide an adhesive dryer surface on which a fiber web can be transferred, dried, and creped.
Description
CREPING METHODS USING PH-MODIFIED
CREPING ADHESIVE COMPOSITIONS
FIELD OF THE INVENTION
This application claims priority from U.S. Provisional Patent Application No.
61/513,716, filed August 1, 2011, which is incorporated in its entirety by reference herein.
The present invention relates to the manufacture of crepe paper including soft,
absorbent tissue paper webs and particularly to the mode of creping of such webs using pH
modified creping adhesive compositions to attain adequate softness and adhesive
characteristics in the web with enhanced creping performance.
BACKGROUND OF THE INVENTION
It is known in the art to form a thin paper web from a slurry of water and fiber,
dewater the wet web, and then at least partially dry the dewatered web. In the manufacture of
tissue and similar paper products, creping is commonly used on such dewatered webs to
impart desirable properties, such as softness and bulk. Creping is typically accomplished by
conveying or carrying the web on a fabric to a heated rotary drum termed in the art a Yankee
dryer. The web commonly is transferred to an adhesive dryer surface of the dryer and carried
around a major circumferential portion of the dryer before the web reaches a zone of web de-
contact from the drum. The de-contact zone is equipped with a creping blade against which
the web abuts so as to be pushed backwardly or compacted upon itself in a machine direction
of the web and attain the well-known tissue crepe paper structure, at which point the resulting
creped web is removed from the dryer and collected, usually in rolled up form.
Before the web is transferred to the Yankee dryer, typically an adhesive
composition, sometimes referred to as a “coating package” in the industry, is applied directly
to the dryer surface of the dryer to form the adhesive dryer surface. The creping action
typically requires some adhesion of the web to the outer surface of the dryer to effect a
consistent and uniform creping action. Creping adhesives alone or in combination with
release agents or other adjuvants have been applied either to the web or to the surface of the
dryer in efforts to provide some balance of adhesion and release between the web and the
dryer surface for purposes of drying and creping.
Various properties of the creping adhesive can be factors in the creping
performance obtained. The rewettability of the creping adhesive on the dryer surface can be
one such factor. An adhesive which can rewet on the surface of the dryer may improve
retention of the web on the dryer surface through creping and assist in reducing buildup on
the drum and on the creping blade. Many conventional creping adhesives are not rewettable.
Further, coating buildup can appear as a build-up of adhesive on the rear surface of the
creping blade, such as along the edges or corners of the creping blade. This adhesive build up
can cause chattering or bouncing of the blade. Eventually, portions of the web may skip
underneath the creping blade, causing picks or holes in the removed creped web, which may
lead to web breaks and machine downtime. The level of adhesion of the creping adhesive to
the drum dryer surface can be another factor which affects creping performance and results.
Inadequate adhesion can result in poor creping, sheet floating, poor sheet handling, or other
problems, whereas excessive adhesion may result in crepe blade picking, web plugging
behind the crepe blade, web breaks due to excessive tension, or other problems.
Various types of creping adhesives have been used to adhere fibrous webs to
rotary dryers such as Yankee dryers. Creping adhesives have included, for example,
polyvinyl acetate-ethylene copolymer emulsions and aqueous polyvinyl alcohol solutions. It
has been found that conventionally used polyvinyl acetate-ethylene copolymer compositions,
which may contain small percentages of polyvinyl alcohol such as less than about 5% of the
total solids by weight, may be generally adequate for the purpose but can cause a number of
undesirable effects, such as blocking problems and others as mentioned in U.S. Patent No.
6,991,707 B2, which is incorporated herein by reference in its entirety. Polyvinyl alcohol
compositions (which may contain some polyvinyl acetate) can pose similar problems when
used as creping adhesives, and can tend to coat the dryer with a hard and uneven film that
builds up as drying and creping proceed, resulting in uneven creping or other problems.
Other creping adhesives have included wet strength resins, such as
polyamidoamines cross-linked with epihalohydrin (PAE). PAE resins are described, for
example, in U.S. Patent Nos. 2,926,116; 7,943,705 B2; and 7,718,035 B2. PAE resins are
generally prepared by reacting an epichlorohydrin and a polyamide containing secondary or
tertiary amine groups, followed by stabilizing the reaction products by acidification with
sulfuric or hydrochloric acid. The creping adhesive desirably should be "rewettable," which
is not a property of many conventional PAE resins as previously synthesized and used. A
non-rewettable adhesive can result in buildup of adhesive on the dryer surface or cause other
problems.
The present investigators have determined that creping performance and
product quality in the manufacture of creped paper products can be enhanced by increasing
the pH of settable or curable coating packages before application to a dryer surface.
SUMMARY OF THE INVENTION
A feature of this invention is to provide a method of enhancing creping
performance by elevating the pH of a coating package before application to a dryer to form a
coating film thereon.
An additional or alternative feature of this invention is to provide a method of
creping with elevating of the pH of a coating package prior to the application to a dryer
surface to provide chemical setting of the coating package with thermal independence or at
least reduced thermal dependence.
An additional or alternative feature of this invention is to provide a method of
creping with upward-adjusting of the pH of a coating package prior to application of the
coating package to a dryer surface to provide chemical set times which are capable of
accommodating more challenging operational conditions, such as shortened dwell times, high
running speeds, lowered dryer steam pressures, lightweight paper grades, smaller diameter
Yankee dryers, or other more extreme operational conditions.
An additional or altrenative feature of this invention is to improve creping
performance by elevating the pH of creping adhesive composition(s) at a mix pot and/or
spray boom before application to a Yankee dryer.
An additional or alternative feature of this invention is to provide a method of
creping using a multifunctional setting agent which can elevate the pH of an adhesive creping
formulation and provide a creping adhesive composition capable of reversible crosslinking
and/or rewettable film formation.
An additional or alternative feature of this invention is to provide creped paper
products of such methods.
An additional or alternative feature of this invention is to provide the public
with a useful choice. Additional features and advantages of the present invention will be set
forth in part in the description which follows, and in part will be apparent from the
description, or may be learned by practice of the present invention. The objectives and other
advantages of the present invention will be realized and obtained by means of the elements
and combinations particularly pointed out in the written description and appended claims.
To achieve these and other advantages and in accordance with the purposes of
the present invention, as embodied and broadly described herein, the present invention, in
part, relates to a method for manufacturing a creped fiber web wherein the method includes
providing a rotating cylindrical dryer which has a dryer surface, a coating applicator fluidly
connected to a feed line (e.g., mixing vessel or supply) containing an adhesive base
formulation which has a first pH of from about 3.5 to about 8.5 (or from about 4.5 to about
8.5) and comprises at least a crosslinkable polymer. A pH modifier is added to the adhesive
base formulation to provide a creping adhesive composition which has a second pH value that
is at least about 0.5 pH units greater than the first pH value. After pH modification (or even
during pH modification), the creping adhesive composition is applied to the dryer surface
with the coating applicator to provide an adhesive dryer surface. A fibrous web is conveyed
into contact with the adhesive dryer surface, the fiber web is dried on the adhesive dryer
surface to form a dried fiber web, and the dried fiber web is creped and removed from the
adhesive dryer surface. As an option, the pH of the adhesive base formulation can be upward
adjusted up to pH about 9.0 before coated on the Yankee dryer. As another option, the
original pH of the adhesive base formulation can be acidic. The crosslinkable polymer can be,
for example, a crosslinkable cationic water-soluble polymer which can be rewettable on the
dryer surface. The adhesive base formulation can further combine the crosslinkable polymer
with one or more of a release modifier (e.g., oil based or aqueous based), a phosphate donor,
a different polymer, or other additives, or any combinations of these. As an option, a
multifunctional setting agent can be used which elevates the pH of an adhesive creping
formulation and provides a creping adhesive composition capable of reversible crosslinking,
which can improve the set time and rewettability of the adhesive film.
[0016a] More specifically, in a first aspect, the present invention provides a process for
manufacturing a creped fiber web, comprising:
providing a rotating cylindrical dryer including a dryer surface;
providing a coating applicator fluidly connected to a supply or feed;
providing an adhesive base formulation in the supply or feed comprising a
crosslinkable polymer, in an aqueous medium having an acidic pH, wherein the adhesive
base formulation has a first pH value, wherein the first pH value is from about 3.5 to about
8.5;
adding a pH modifier to said adhesive base formulation to provide a creping adhesive
composition having a second pH value, wherein the second pH value is at least about 0.5 pH
units greater than the first pH value, wherein said adding of said pH modifier comprises
introducing said pH modifier as a premixture with water to a mixing vessel, to make-up
water, to a feed going to a boom, or a return to a mixing vessel, or any combination thereof;
applying said creping adhesive composition to the dryer surface with the coating
applicator to provide an adhesive dryer surface;
conveying a fibrous web into contact with the adhesive dryer surface;
drying the fiber web on said adhesive dryer surface to form a dried fiber web; and
creping the dried fiber web from said adhesive dryer surface,
wherein the adding of the pH modifier to said adhesive base formulation is effective
for chemically setting at least a portion of the crosslinkable polymer to form a crosslinked
polymer before the creping adhesive composition contacts the dryer surface.
[0016b] In a second aspect, the present invention provides a process of making creped
fiber web, comprising:
increasing the pH of an adhesive base formulation that is to be used on a dryer
surface, wherein said adhesive base formulation comprises at least one crosslinkable
polymer, wherein the adhesive base formulation has a first pH value that is from about 4.5 to
about 8.5, and said increasing of the pH is by at least about 0.5 pH units greater than the first
pH value so as to form a creping adhesive composition,; and
applying said adhesive base formulation to the dryer surface with a spray boom
wherein said increasing of the pH occurs in a mixing pot, make-up water, or a feed line to
said spray boom prior to said applying with the spray boom;
conveying a fibrous web into contact with the dryer surface having said adhesive base
formulation;
drying the fiber web to form a dried fiber web; and
creping the dried fiber web,
wherein adding a pH modifier to said adhesive base formulation is effective for
chemically setting at least a portion of the crosslinkable polymer to form a crosslinked
polymer before the adhesive base formulation contacts the dryer surface.
The present invention further relates to creped fiber products made from the
indicated processes.
[0017a] The term “comprising” as used in this specification and claims means
“consisting at least in part of”. When interpreting statements in this specification and claims
which include the term “comprising”, other features besides the features prefaced by this term
in each statement can also be present. Related terms such as “comprise” and “comprises” are
to be interpreted in similar manner.
As used herein, “setting” refers to a crosslinking reaction which includes a
crosslinkable polymer to form a crosslinked or thermoset polymer material.
As used herein, “chemically setting” refers to a chemical reaction of at least
one crosslinkable polymer and a setting agent which forms a crosslinked or thermoset
polymer material. Heating is not a required part of this definition, although system heat,
whether ambient or actively provided, may contribute in some part, or not at all, to the overall
setting process.
The term “rewettable” or “rewetting” and similar variants refers to the
capability of a polymer to change from a crosslinked or chemically set state to a tacky
condition.
As used herein, the “coating package” refers to the complete coating
formulation which is applied to the dryer surface of the rotary dryer. As used herein, a “base
formulation” can be supplemented with a pH modifier to provide a coating package of the
present invention. As used herein, a “base formulation” is a chronological characterization of
an adhesive formulation, which can be supplemented with different components before use,
such as the indicated pH modifier.
Additional features and advantages of the present invention will be set forth in
part in the description that follows, and in part will be apparent from the description, or may be
learned by practice of the present invention. The objectives and other advantages of the present
invention will be realized and attained by means of the elements and combinations particularly
pointed out in the description and appended claims.
It is to be understood that both the foregoing general description and the
following detailed description are exemplary only and are not restrictive of the present
invention, as claimed. All patents, patent applications, and publications mentioned above and
throughout the present application are incorporated in their entirety by reference herein. In
this specification where reference has been made to patent specifications, other external
documents, or other sources of information, this is generally for the purpose of providing a
context for discussing the features of the invention. Unless specifically stated otherwise,
reference to such external documents is not to be construed as an admission that such
documents, or such sources of information, in any jurisdiction, are prior art, or form part of
the common general knowledge in the art.
The accompanying drawings, which are incorporated in and constitute a part
of this application, illustrate some of the features of the present invention and together with
the description, serve to explain the principles of the present invention.
[0024a] In the description in this specification reference may be made to subject matter
which is not within the scope of the appended claims. That subject matter should be readily
identifiable by a person skilled in the art and may assist in putting into practice the invention
as defined in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may be more fully understood with reference to the
accompanying figures. The figures are intended to illustrate exemplary features of the present
invention without limiting the scope of the invention.
is a flow chart illustrating a process according to the present invention.
is a schematic illustration of a creping system that can be used to
perform a creping method according to the present invention.
is a table showing various testing parameters for a creping operation
using a creping adhesive composition which is pH modified according to a method of the
present invention (Example 1).
is a table showing various testing parameters for a creping operation
using a creping adhesive composition which is pH modified according to a method of the
present invention (Example 2).
DETAILED DESCRIPTION OF THE PRESENT INVENTION
According to the present invention, a method of manufacturing crepe paper,
including soft, absorbent tissue paper webs, and particularly to modes of creping of such
webs using pH modifications of creping adhesives are provided with improved creping
performance while minimizing operational difficulties and accommodating a wide range of
operating conditions. Enhanced creping performance can be achieved by elevating the pH of
an adhesive base formulation (having an original pH of from about 3.5 to about 8.5, or from
about 4.5 to about 8.5) by at least about 0.5 pH units before coated on a rotary dryer with the
resulting composition. The pH modification can initiate setting (crosslinking) or speed up the
setting of at least one crosslinkable adhesive component of the coating package prior to
establishing contact with the Yankee surface or other dryer surface. These enhancements may
take the form, for example, of thicker coating film development with faster setting rates and
coating film development on the dryer along with reduced streaking, chatter, and/or
corrugation, as compared to the performance of the original unmodified adhesive
composition (i.e., without the pH elevation adjustment). Higher visual coating development,
for example, can be achieved, even at reduced add-on rates.
Further, as an option, the coating package can be set chemically, at least in
part, or primarily, or completely, instead of thermally set. A chemically-set creping adhesive
composition or coating package can be provided by driving cross-linking of at least one
crosslinkable polymer component of the adhesive base formulation by increased pH.
Elevating the pH of an adhesive base formulation before reaching and/or in a coating
applicator, such as a spray boom of a Yankee dryer, can facilitate the setting rate of the
coating package independent of any thermal treatment or activation applied to the coating
package. The method can reduce or eliminate thermal setting requirements for the coating
package. Even though chemical setting is initiated by the indicated pH modification before
the adhesive composition is coated on the dryer, it can remain coatable with a sprayer or
other coating device. The change in pH provided in the methods of the present invention can
accelerate film formation on the dryer. This effect of accelerating the setting of the adhesive
by a chemical treatment can be especially useful for Yankee dryers, such as small diameter
Yankee dryers, operated with short dwell times (e.g., from coating application to suction
press roll (SPR) nip), low steam pressures, high running speeds, lightweight paper grades
(e.g., 8.8#), and other more extreme operating conditions.
The setting rate provided in the creping adhesive composition by addition of
the pH modifier in methods of the present invention can be a direct positive function of the
amount of pH increase imparted. For example, greater imparted pH increases can yield
corresponding faster setting rates. Using a higher pH creping adhesive composition in a spray
boom or other coating applicator can reduce corrosion on equipment coming into contact
with the creping adhesive composition. The level of pH increase imparted can be controlled
to adjust the window of the set point of the coatings to balance setting and tack properties of
the coated film. The level of pH increase imparted can be increased until sheet float is
encountered. The pH of the adhesive base formulation can be upward adjusted up to about
9.0 before coated on the Yankee dryer.
As another option, the inducement of setting by the pH modification as
indicated can provide a creping adhesive composition capable of reversible crosslinking. This
property can improve the set time and rewettability of the adhesive film. By elevating the pH,
visibly better coating build-up and reduced release aid requirements can be provided. The
methods of the present invention can provide the creping operator with additional tools and
options to control the coating package. The resulting creping adhesive compositions may
form thickened coating films on the dryer surface with suitable adhesion properties for
creping.
For purposes of the present invention, the pH modification of the present
invention can occur at any location (or multiple locations) up to where the adhesive base
formulation is applied to the dryer surface. The adhesive base formulation prior to pH
modification as described herein can be fed to the coating applicator(s) from a supply or feed
(e.g., one or more feed lines (once through feed lines or closed loops systems), mixing pot,
mixing vessel, supply tank, and the like). The pH modification can even occur at the time of
contacting the dryer surface. The pH modification can be accomplished on a continuous,
semi-continuous, or as batches. The pH modification can be done to form a pre-mixture that
is added to the dryer surface. The pH modification can be done through a feed line where the
pH modifier is added to the adhesive base formulation through a feed line or drip line or any
feed to achieve the desired pH modification described herein. The pH modification of the
present invention to form the creping adhesive composition of the present invention can be
achieved in a mixing vessel, mixing pot, in the make up water, in the feed to the spray boom,
in the return to a mixing tank. The present invention can be used in a once through system
and/or a closed-loop system. The present invention can be used in a pressurized system, such
as a pressurized closed loop system.
After the indicated pH modification, the resulting creping adhesive
composition can be coated onto a dryer surface to form an adhesive dryer surface and
combined with a partially dewatered paper web for creping. A partially dewatered paper web
can be transferred to the adhesive dryer surface, for example, and then can be carried on the
rotating dryer for further dewatering until reaching a creping blade or other creping device.
The creping device crepes the web, and the resulting creped web is removed from the dryer
and collected, such as on a reel. After removal of the creped web, the dryer surface optionally
can be cleaned, and then can be rotated back to the adhesive coating zone, and the indicated
process cycle can be repeated as part of a continuous or semi-continuous running mode. As
stated, a feature of the method of the present invention is the pH modification of an adhesive
base formulation before coating on the dryer. The components of the adhesive base
formulation can be combined in a mix pot or other suitable mixing vessel to provide a base
formulation which can rapidly reach a steady-state pH value before addition of the pH
modifier in the range of from about 3.5 to about 8.5 or from about 4.5 to about 8.5, or from
about 5 to about 8 or from about 5.5 to about 8, or from about 4.5 to about 6, or from about 4
to about 7. As another option, the original pH of the adhesive base formulation can be acidic
(i.e., < pH 7.0), and the pH can be upward adjusted up to about 9.0. As used herein with
respect to pH value, “steady-state pH value” refers to a value which can have ± 0.25 tolerance
when successively measured the same way. If slight variations in pH values within the
indicated tolerance are measured for the adhesive base formulation before addition of the pH
modifier, the largest measured pH value is used as the reference point for calculating the
adjusted pH value which will have at least a 0.5 pH unit increase provided by adding the pH
modifier. As an option, the pH modifier can be added to the adhesive base formulation in an
amount which increases the pH of the resulting creping adhesive composition as compared to
the original pH of the adhesive base formulation at least about 0.5 pH units, or at least about
0.6 pH units, or at least about 0.7 pH units, or at least about 0.8 pH units, or at least about 0.9
pH units, or at least about 1.0 pH units, or at least about 1.5 pH units, or at least about 2.0 pH
units, or at least about 2.5 pH units, or at least about 3.0 pH units, or from about 0.5 to about
3.0 pH units, or from about 0.6 to about 2.5 pH units, or from about 0.7 to about 2.0 pH units,
or from about 0.8 to about 1.5 pH units, or from about 0.9 to about 4.0 pH units, or other ≥0.5
pH unit increases relative to the pH of the adhesive base formulation. The pH values of
adhesive base formulation and creping adhesive composition are based on at least one pH
measurement taken from the respective composition, or an extracted sample thereof, after all
of the components of the respective formulation or composition have been combined and
stirred or otherwise agitated to provide a substantially uniform mixture of the components
added to that point and a steady-state pH value is provided. A conventional submersible pH
probe, or other suitable submersible pH measuring device, which can support real time
measurements and display of results, can be used.
When upward adjusted at least about 0.5 pH units, the resulting creping
adhesive composition from the pH modification can be rapidly settable while still being
coatable via a spray boom or other applicator to a dryer surface. The chemical setting of the
creping adhesive which is provided in the present method with the pH adjustments can permit
the Yankee dryer to be operated at lower temperature with less energy requirements and less
dependence on temperature control. For example, the crosslinkable polymer in the adhesive
base formulation can be crosslinked with less dependence on or independence from
temperature settings or adjustments (e.g., heating) made to the composition on or off the
Yankee drum. Requirements for thermal activation of the adhesive on the dryer surface can
be reduced in the methods of the present invention. This can permit reduced heating
requirements at the dryer, increased run speeds of the web and dryer, shorter web dwell times
on the dryer, or combinations of these advantages.
The indicated pH modification can provide improvements in creping
performance and product quality as compared to use of the adhesive base formulation without
the indicated pH modification. For example, coatings with thickened development or
continuous development at reduced add-on, less streaks, reduced chatter, reduced
corrugation, or combinations of these advantages on the Yankee dryer can be provided.
Further, the method can provide creping adhesive compositions which are rewettable to
enhance creping quality and performance. A rewettable adhesive can be capable of being
activated (rewetted) on the dryer surface, for example, when a pressure roller brings the paper
web into initial contact with the adhesive on the dryer surface. This activation can occur in
part, for example, from the chemical structure of the adhesive, additives used, the moisture
content in the web, or combinations of these or other reasons. Rewettability also may affect
adhesiveness, particularly as the moisture content in the web decreases, such as in higher
fiber-consistency (lower moisture content) webs. The methods of the present invention also
may assist in controlling wear, corrosion, or both, on the Yankee dryer and creping blade
surfaces, which, if achieved, can reduce equipment maintenance requirements and production
downtimes.
Although this application illustrates the method with reference generally to a
tissue paper at instances, it will be appreciated that the invention can be used for manufacture
of a wide variety of creped paper products, such as bath tissue, paper towels, facial tissue,
paper napkins, filter papers, coffee filters, sanitary napkin wrappers, and other creped paper
products. The creped paper products can be single-ply or multi-ply products.
Referring now to the drawings, is a flow chart showing a series of steps
included in a method according to the present invention that can be used for the formation of
a creped tissue paper web (process 100). Such webs can have a finished basis weight, for
example, in the range of from about 1 to about 80 pounds per 3,000 square feet, or from
about 7 to about 40 pounds per 3,000 square feet, or other basis weights, and can be formed
from aqueous fiber slurries. According to the present invention, in steps 101-102, a thin
paper web can be formed from a slurry of water and fiber using a conventional web forming
technique or other suitable method, and then in step 103, the web can be dewatered at least in
part, such as at least partially dried. For example, the slurry can be directed to a conventional
Fourdrinier drainage wire to form a fiber web. Dewatering of the fiber web can occur through
the wire in a conventional manner. The fibrous web can be formed of various types of wood
pulp based fibers which are used to make the above products, such as hardwood kraft fibers,
softwood kraft fibers, hardwood sulfite fibers, softwood sulfite fibers, chemi-thermo-
mechanical fibers, thermomechanical pulps, refiner mechanical pulps, recycled paper fibers,
or other pulp fibers, or any combinations thereof. As an option, before transfer to the Yankee
dryer or other rotary dryer, the fiber web can be dried to a fiber consistency of from about
% by weight to about 90% by weight, or from about 20% by weight to about 80% by
weight, or from about 25% by weight to about 75% by weight, or from about 40% by weight
to about 60% by weight, or from 40% by weight to about 50% by weight, or other values,
before being conveyed to the web dryer surface. For purposes herein, “fiber consistency”
refers to the percentage value of dry fiber weight relative to the total weight of the web. As an
option, the “moisture content” of the web may constitute most or all of the balance of the web
weight. For example, the fibrous web, prior to application to the Yankee dryer or other rotary
dryer, can have moisture contents, for example, of from about 90% by weight to about 10%
by weight, or from about 75% to about 25% by weight to about 75% by weight, or from
about 60% by weight to about 40% by weight, or from about 50% to about 60% by weight, or
other values, can be processed according to the methods of the present invention. Such webs
accordingly would have fiber contents making up the additional weight % of the web. After
dewatering, the web can then be conveyed, e.g., carried on a fabric, to a creping dryer or web
dryer, which can be, for example, a steam-heated rotary drum dryer, referred to herein and
elsewhere as a Yankee dryer. Before receiving the fiber web, an adhesive dryer surface of
the Yankee dryer is prepared in a unique manner as part of the present method, which can
involve steps 104-106 in this illustration.
In step 104 shown in creping adhesive base formulation components
are fed, recirculated, or both into a mixing pot or other suitable mixing vessel, which can be
equipped for agitation of its contents. Although not shown, the creping adhesive base
formulation components can be fed into a closed loop system, such as a pressurized closed
loop system, or can be fed into a once through application system. As an option, the creping
adhesive composition can be prepared as an aqueous film-forming dispersion of the active
components including a crosslinkable polymer, a pH modifier, and any other additives. As an
option, the crosslinkable polymers are sourced as acidic compositions (e.g., pHs from about
3.5 to about 6.0 or higher, or from about 4.5 to about 5.5, or from about 4.5 to about 5.0, or
other acidic pH values). In step 105, a pH modifier is added of a type and amount effective
to increase the pH of the contents at least 0.5 pH units (e.g., increased to a pH of 4 or higher,
such as a pH of 4.5 or 5.0 or higher, such as or 6.0, or 7.0, or 8.0, or higher values up to pH
about 9.0, or other ≥ 0.5 increases between pH 5-9). In step, 106, the resulting creping
adhesive composition is coated on a dryer surface of a Yankee dryer or other large rotary
dryer, and an adhesive dryer surface is formed. As an option, creping adhesive compositions
can be applied to the Yankee surface as the sole active agent, or optionally with a release aid,
and further optionally with a phosphate donor or other additives and resins, through the same
spray boom or other coating applicator. As an option, creping adhesives alone or in
combination with release agents can be applied to the surface of the dryer in order to provide
the appropriate adhesion to produce the desired crepe. As generally understood, the adhesive
portion and any release aids used in the coating composition may migrate differentially as
between a hot Yankee surface and the opposite web surface. Adhesion modifiers, if used,
may assist in controlling the adhesion force to assist crepe within a broader range of moisture
operation. As an option, the spray boom or other coating applicator can be located after the
creping blade and any cleaning blade, but before the pressure roll, using specific geometries
and spray pressures to achieve desired results.
In step 107 shown in the dewatered and partially dried wet paper web
is conveyed, for example, carried on a fabric, to the adhesive dryer surface of a large rotary
dryer, such as a steam-heated and/or hood heated rotary drum dryer, referred to herein and
elsewhere as the Yankee dryer. A Yankee dryer can be a large diameter, typically about 8 to
about 20 foot diameter drum, or other diameters, which is designed to be pressurized with
steam to provide a hot surface for completing the drying of papermaking webs at the end of
the papermaking process. The web can be transferred to the dryer, for example, at a
circumferential dryer position, such as a position at least about halfway around, or at least
about 75% around, the cylindrical dryer with respect to the zone of web de-contact where the
creped web is separated and removed from the drum. The transfer fabric can be, for example,
a transfer and impression fabric having knuckles which can compact a portion, e.g., about
% or other amounts, of the surface of the web on a creping or Yankee dryer, to form a
knuckled fiber web. As an option, the creping adhesive composition can retain the knuckled
fiber web on the web dryer surface until a fiber consistency of the web is about 75% by
weight or more, for example, at least about 95% by weight. In some modes of operation
referred to herein as through-air drying, contact of the web with the dryer surface is limited.
Methods and systems of through-drying operations which optionally may be used in the
present invention include those such as described in U.S. Patent No. 6,991,707 B2, which is
incorporated herein by reference. The methods of the present invention can be used, for
example, with through-air drying systems with creping methods, with Yankee dryer systems
and methods, and with wet-crepe machines, systems, and methods. In step 108, the web can
be retained on the adhesive dryer surface while carried around or on the dryer until reaching a
de-contact zone. In step 109, the de-contact zone can be equipped with a creping device,
such as a creping blade or doctor blade, against which the web abuts so as to be pushed or
compacted backwardly upon itself and attain a recognizable tissue crepe paper structure. In
step 110, the creped web can be recovered off the dryer. The web can be creped from the
dryer to form a dried web having a fiber content or consistency, for example, of about 75%
by weight or higher, for example, at least about 90% by weight, or at least about 95% by
weight, or at least about 97% by weight consistency, and then can be wound into rolls or
otherwise be collected off the dryer. At the creping stage, the fibrous web can have a water
content, for example, of less than 25% by weight, or less than about 10% by weight, or less
than about 7% by weight, or less than about 5% by weight, or other amounts.
The creping adhesive compositions or coating packages used in methods
according to the present invention include at least one crosslinkable polymer. The polymer
can be partially crosslinked, but not completely cross-linked, wherein it can have some
crosslinkability still available when added to the adhesive base formulation. The
crosslinkable polymer can be, for example, a self-crosslinkable polymer used alone, or a
crosslinkable polymer used in combination with one or more different crosslinkable or non-
crosslinkable polymers. The crosslinkable polymer can be rewettable. As an option, the
crosslinkable polymer can be any polymer which can form a continuous or substantially
continuous film when dried from an aqueous solution on a dryer surface of a Yankee dryer.
Crosslinkable polymers useful in the present invention can include, for
example, crosslinkable natural polymers, crosslinkable synthetic polymers, crosslinkable
thermoplastic polymers, thermosetting polymers, or any combinations thereof. The
crosslinkable polymers can be, for example, homopolymers, copolymers, block copolymers,
multi-stage polymers, star polymers, or any combinations thereof. Non-limiting examples of
polymer chemistries include, but are not limited to, ethylene vinyl acetate polymers, acrylic
homopolymers and copolymers, vinyl acetate homopolymers, polyamides, polyvinyl
alcohols, starches, cellulosics, poly(aminoamide)-epichlorohydrins (PAEs), ionene polymers,
polymeric quaternary ammonium compounds (polyquats), or other polymers, or any
combinations thereof. The polymer can be functionalized to provide crosslinking
functionality. Other crosslinkable polymers which may be used include those mentioned, for
example, in U.S. Patent No. 5,246,544, which is incorporated herein by reference in its
entirety.
The crosslinkable polymer can be, for example, a crosslinkable cationic water-
soluble polymer. Polymers which can be used include, for example, BUBOND® series
release agents, such as BUBOND® 2062, BUBOND® 2624, sold by Buckman Laboratories
International Inc., Memphis, TN USA. Crosslinkable or partially crosslinked, partially
crosslinkable PAE type resins may be used. PAE resins synthesized with a small excess of
epihalohydrin with the extent of crosslinking controlled to terminate by the addition of acid
before reaching completion can be used, such as mentioned in U.S. Patent No. 7,718,035 B2,
which is incorporated herein by reference in its entirety. CREPETROL® 5318, for example,
a commercial PAE creping adhesive sold by Hercules Incorporated, can be used. Partially or
lightly crosslinked ionene polymers or polymeric quaternary ammonium compounds
(polyquats) may be used, such as mentioned in U.S. Patent No. 6,991,707 B2, which is
incorporated herein by reference in its entirety.
A second or more optional polymer which can be used with the crosslinkable
polymer can be, for example, a wet strength or hard cationic resin or polymer that is non-
crosslinkable or crosslinkable. Another type of optional polymer which may be used can be a
soft polymer which has a lot of tack, which may assist edge control at high running speeds. A
non-limiting commercial example of such a soft, yet tacky resin is PROSOFT® TC9700, an
EPI-crosslinked poly(aminoamide), sold by Hercules Incorporated. Other optional polymers
which may be used include, for example, CREPETROL® 1145, or any other crosslinking
adhesive of a pH below 5.
The crosslinkable polymer concentration in the creping adhesive composition
can depend in part on the coating process used to apply the coating on a dryer surface. In
spray boom applications, the total crosslinkable polymer solids of the creping adhesive
composition can range, for example, from about 0.05% by weight to about 20% by weight, or
from about 0.1% by weight to about 15% by weight, or from about 0.5% by weight to about
12% by weight, or from about 0.75% by weight to about 10% by weight, or from about 1%
by weight to about 7% by weight, or from about 1.5% by weight to about 5% by weight,
based on the total weight of a sprayable composition (solids and liquids). As an option, the
sprayable creping adhesive composition can comprise the crosslinkable polymer in a
concentration of from about 1% by weight to about 99% by weight, or from about 3% by
weight to about 95% by weight, or from about 4% by weight to about 75% by weight, or
from about 5% by weight to about 50% by weight, or from about 7% by weight to about 30%
by weight, based on total dry solids weight of the creping adhesive composition.
Examples of pH modifiers that can be used to elevate the pH of the adhesive
base formulation include, for example, caustic materials, alkali materials (e.g., alkali metal
materials, alkaline earth metal materials), and basic buffering materials, or any combinations
thereof. The pH modifier can be inorganic or organic, or combinations and mixtures of these
different types of pH-modifying materials. The pH modifier can be, for example, an alkali
metal hydroxide, an alkali metal oxide, an alkali metal phosphate, an alkali metal carbonate,
an alkali metal bicarbonate, an alkaline earth hydroxide, an alkaline earth oxide, an alkaline
earth phosphate, an alkaline earth carbonate, ammonium zirconium carbonate, organotitanate,
organozirconate, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate,
alkali metal silicate, urea, substituted urea, a cyanate, an alkylamine, an alkanolamine, a
quaternary ammonium salt, a salt of a weak acid and a strong base, an alkaline buffering
solution, polyalkali metal pyrophosphates, or any combinations thereof.
An example of an
alkali metal hydroxide which may be used is NaOH. Example of alkaline earth metal
hydroxide which may be used, for example, are Mg(OH) , Ca(OH) , or any combinations
thereof. The alkali salts can be used as brines or in water-soluble salt forms. As an option, an
alkaline buffering agent can be used in the adhesive base formulation to establish alkalinity
and resist pH changes. Examples of alkaline buffers which can be used include, for example,
magnesium oxide, and an aqueous solution of disodium phosphate and monosodium
phosphate. Examples of alkanolamines include triethanolamine, diethanolamine, or
monoethanolamine. The pH modifier can be, for example, an Arrhenius base (i.e., a
substance that ionizes in water to produce hydroxide ions), a Brønsted-Lowry base (i.e., a
substance that can accept a proton or hydrogen cation (H )), or a Lewis base (i.e., a species
that donates an electron pair), provided its introduction can affect an increase in the pH of an
adhesive base formulation. The dosage rate of the pH modifier depends on factors of the level
of pH increase sought, the base strength of the particular material, and the addition rate. As a
non-limiting example, to increase the pH about 0.5 units, a 10% by weight NaOH solution
can be added in a wt:wt ratio (solids only basis) to crosslinkable polymer having an original
pH in water of about 4.0 to about 6.0 in a range amount of about 1/30 to about 30/1, such as
1/10 or 10/1, or other range values. The magnitude of further increases in pH obtained by
further increasing the amount of pH modifier added may be approximately proportional or at
least may trend together.
As an option, a multi-functional agent can be used which increases the pH of
the adhesive base formulation and performs at least one different function when used in the
adhesive base formulation. The different function, for example, can be a processing aid
function or a performance agent function. For example, a multi-functional setting agent can
be used which increases the pH of the adhesive base formulation and structurally participates
in the crosslinking of the crosslinkable polymer. Multi-functional crosslinking materials of
this type can include, for example, ammonium zirconium carbonate, organotitanates,
organozirconates, or like materials. Additional multi-functional setting agents which can be
used in methods of the present invention are described, for example, in U.S. Patent Nos.
4,837,272 and 6,663,942 B1, which are incorporated herein by reference in their entireties.
As an option, a polyalkali metal pyrophosphate can be added to the adhesive
base formulation to increase the pH of the resulting creping adhesive composition, which
additionally can provide at least one other function, such as reducing or eliminating coating
streaks, minimizing corrugation on the creping drum/rolls, or providing combinations of
these or other affects, in the manufacture of creped fiber web in a process of the present
invention. For example, a polyalkali metal pyrophosphate can be used to increase the pH of
an adhesive base formulation which has an original pH value in the range of about 4.5 to
about 8.5, such as an original acidic value (pH <7.0, e.g., pH about 3-4), at least 0.5 pH units,
and to reduce coating streaks and/or minimize corrugation in providing a creping adhesive
composition suitable for use in the process of the present invention. The polyalkali metal
pyrophosphate can be, for example, tetrapotassium pyrophosphate, tetrasodium
pyrophosphate, or salts thereof, or any combinations thereof. A polyalkali metal
pyrophosphate in an aqueous form can be used for the addition or combination with an
adhesive base formulation as described herein. For example, a tetrapotassium pyrophosphate
(TKPP) salt (e.g., CAS No. 73205) in water can be used (e.g., CAS No. 77325). As
another example, tetrasodium pyrophosphate (TSPP) salt (e.g., CAS No. 77225) in water
can be used. For example, about 50 wt% to about 70 wt% TKPP singly, TSPP singly, or
combinations thereof, in water or other concentrations can be used as a multi-functional agent
in combination with an adhesive base formulation that is used in a process of the present
invention. A commercial product which contains TKPP, which can be used as such a multi-
functional agent in a process of the present invention, is BUSPERSE® 2436, sold by
Buckman Laboratories International Inc., Memphis, TN USA. The higher the dosage of
polyalkali metal pyrophosphate added to an adhesive base formulation on an application rate
basis (e.g., mg/m ) in a process of the present invention, the greater the increased pH
adjustment in the resulting creping adhesive composition that can be provided. The higher the
dosage of polyalkali metal pyrophosphate added to the adhesive base formulation, the less the
coating streaks that tend to build up when using the resulting creping adhesive composition
on a creping roll or drum. Similarly, the extent of corrugation in the creped fiber web can be
further minimized by increasing the dosage of the polyalkali metal pyrophosphate added to
the adhesive base formulation. The use of polyalkali metal pyrophosphate as a multi-
functional pH modifier also can allow for the use of reduced dosage of the crosslinkable
polymer in the adhesive base formulation on an application rate basis (mg/m ), and allow the
sheet quality to be maintained by controlling the set point of the adhesive for optimal
tackiness. An upper limit on the dosage of the polyalkali metal pyrophosphate used in the
creping adhesive composition may be reached if the crosslinkable polymer reacts too rapidly,
which may make it difficult to pick up the sheet at the pressure roll and result in severe
corrugation.
In addition to the indicated pH modifier, the creping adhesive composition
comprising the crosslinkable polymer can comprise one or more release agents, as well as
other additives that may affect the creping process. Suitable creping release agents are, for
example, described in U.S. Patent Nos. 5,660,687 and 5,833,806, incorporated herein by
reference in their entireties. Other release agents which can be used include, for example,
BUSPERSE® series release agents, such as BUSPERSE® 2097, BUSPERSE® 2906, which
are sold by Buckman Laboratories International Inc., Memphis, TN USA. The creping action
can be facilitated by ensuring that the web is adhered to the dryer to effect a consistent and
uniform creping action, and for example, to prevent flaring of the web from the dryer before
or at the exit zone in the vicinity of the creping blade. The tightness of the adhesion of the
web to the dryer optionally can be controlled (e.g., reduced) by using a release agent, such as
silicone oil, other oils, surfactants, soaps, shampoos, or conventional additives for creping
adhesives or other adhesives. A release agent, if used to limit adhesion, can either be applied
between the surface of at least one of the dryer and the web, mixed with the adhesive base
formulation, or combinations of these. Other processing aids which can be used include, for
example, BUSPERSE® 2906, which is sold by Buckman Laboratories International Inc.,
Memphis, TN USA. BUSPERSE® 2906, for example, can help to control coating build-up at
the cleaning blade and can also slow down coating streak build-up. The additives can be used
in amounts effective for providing the indicated or other effects. The indicated polyalkali
metal pyrophosphates, such as BUSPERSE® 2436, also may be used as an additive that is
included in the creping adhesive composition in an amount which does not necessarily cause
a pH increase of at least about 0.5 pH, but is sufficient to impart other desired processing or
performance aids or benefits.
In addition to the adhesive components and release agent additives, creping
adhesive formulations can further comprise surfactants, dispersants, salts to adjust the water
hardness, modifiers, anti-corrosion agents, fillers, opacity agents, whiteners, crosslinking
agents, or other useful additives. By including a small amount of monoammonium phosphate
(MAP), for example, the adhesive formulation can minimize corrosion that may otherwise be
caused by chlorides in or from any ionene or other chlorine-containing polymer(s), if used.
Other Yankee cylinder protection/corrosion inhibition agents which may be used include, for
example, BUTROL® series agents, sold by Buckman Laboratories International Inc.,
Memphis, TN USA. Suitable additional modifiers include, but are not limited to, tackifier
resins of U.S. Patent No. 6,133,405, or the stabilizers of the U.S. Patent No. 6,280,571, which
are incorporated herein by reference in their entireties. A crosslinking agent or catalyst can be
included in the adhesive base formulation, which can promote crosslinking, depending on the
type of polymer used and the crosslinking agent.
Application of the creping adhesive compositions to a dryer surface of a
Yankee dryer or other rotary dryer can be done in any manner known in the art and in forms
comprising aqueous, solid, dispersion, or aerosol. As stated, a preferred option of application
is via a spray boom directed at the surface of the drying surface prior to transfer of the paper
web. Spray application of the creping adhesive composition can be done according to any of
the conventional methods known in the art or any desired combination of application
procedures.
Referring to Fig. 2, a system 200 is shown for creping tissue with applying of
a creping adhesive composition 218 to a Yankee dryer 205 according to a method of the
present invention. The transfer and impression fabric designated reference numeral 201 can
carry the formed, dewatered and partially dried web 202 around turning roll 203 to the nip
between press roll 204 and Yankee dryer 205. A supplemental lower carrier designated at 216
may also be employed to carry the web in sandwich fashion, which may be particularly useful
under conditions of higher web dryness. The fabric, web, and dryer move in the directions
indicated by the arrows. The entry of the web into the dryer is well around the roll from
creping blade 206, which, as is schematically indicated, crepes the traveling web from the
dryer as indicated at 207. The creped web 207 exiting from the dryer passes over guide and
tension rollers 208, 209 and is wound into a soft creped tissue roll 210. To adhere a partially
dried and dewatered paper web 202 (at, for example, 10-90 wt.% fiber consistency) entering
the dryer to the surface of the dryer, a spray boom 211 can be used to apply a creping
adhesive composition 218 to the dryer surface 213 which is exposed after de-contacting the
creped tissue web 207 from the dryer 205 to provide an adhesive dryer surface 214 ahead of
the nip between the press roll 204 and Yankee 205. The spray boom 211 can be a single spray
boom or multi-spray boom, such as a dual-spray boom as illustrated. The spray boom can
include an overspray collection container (not shown). The spray boom 211 is fluidly
connected 219 to a mixing pot 215 for feeding creping adhesive composition from the mixing
pot after pH modification. The mixing pot 215 can be equipped with an agitator 217. The
mixing pot can be fed the adhesive base formulation components of the creping adhesive
composition and water via feed supply lines (not shown). To reduce potential local alkaline
shock to the adhesive base formulation, the pH modifier can be, for example, diluted with the
feed water in advance of being supplied to the mixing pot 215, added with vigorous agitation
of the mix pot contents, or both. The adhesive base formulation components including the
crosslinkable polymer and pH modifier can be introduced into the mixing pot 215 in any
convenient manner. The resulting pH modified creping adhesive composition can be pumped
or otherwise fed under pressure to the nozzle sprayer(s) of the spray boom 211. To promote
drying of the web on the dryer, the Yankee 205 can be internally steam heated by
conventional or other suitable arrangements (not shown), externally heated using a hood 212,
or using both. This sprayed composition 218 optionally may be applied to the traveling web
202 directly, but is preferably directly sprayed onto the dryer surface 213, such as to limit the
pickup of adhesive by the web and to limit the penetration of adhesive through the web to the
carrying fabric. Sprayer systems and arrangements which can be adapted and used in
methods of the present invention include, for example, those described in U.S. Patent No.
6,465,047 B1, which is incorporated herein by reference in its entirety.
As an option, the spray can be aqueous and suitably has a total solids content
of from about 0.5% by weight to as much as about 80% by weight total solids, or from about
0.75% by weight to about 20% by weight total solids, or from about 1% by weight to about
% by weight total solids, although any suitable solids content can be used. For roll coating
of the creping adhesive composition onto the dryer surface, or knife coating, higher total
solids contents may be employed, such as, for example, from about 1% by weight to about
70% by weight, for example, from about 3% by weight to about 50% by weight.
The creping adhesive composition can be applied to the dryer surface at a rate,
relative to the rate of dryer surface rotation, which provides an adequate amount of adhesive
to hold the web during drying yet release the dried web upon completion of drying.
Conventional adhesive coverage rates and weights can be used as are known to those skilled
in the art. The creping adhesive composition can be continuously applied to the rotating
dryer so that an adequate amount of adhesive is always on the dryer surface.
Exemplary application rates of the creping adhesive composition on the dryer
surface can provide an application rate of the crosslinkable polymer component thereof in a
2 2 2
range, for example, of from about 0.5 mg/m to about 100 mg/m , or from about 1 mg/m to
2 2 2 2
about 75 mg/m , or from about 1.5 mg/m to about 50 mg/m , or from about 2 mg/m to
2 2 2 2
about 30 mg/m , or from about 2.5 mg/m to about 25 mg/m , or from about 3 mg/m to
2 2 2
about 20 mg/m , or from about 3.5 mg/m to about 10 mg/m , or other rates, based on the
solids weight of the crosslinkable polymer and coated dryer surface area. If used as a pH
modifier added to the adhesive base formulation, a polyalkali metal pyrophosphate (e.g.,
TKPP or TSPP) can be applied as part of a resulting creping adhesive composition to a dryer
surface of a rotating cylindrical dryer at a rate, for example, of from about 0.5 mg/m or
2 2 2
more, or from about 0.5 mg/m to about 5.5 mg/m , or from about 0.75 mg/m to about 4.5
2 2 2 2
mg/m , or from about 1.0 mg/m to about 3 mg/m , or from about 1.2 mg/m to about 2.75
mg/m , on a dry solid basis, or other rates. If used in combination with the crosslinkable
polymer in the creping adhesive composition, a release aid, can be used in an application rate
in a range, for example, of from about 1 mg/m to as much as 150 mg/m , or from about 3
2 2 2 2
mg/m to about 100 mg/m , or from about 5 mg/m to about 50 mg/m , or from about 7
2 2 2 2
mg/m to about 30 mg/m , or from about 10 mg/m to about 25 mg/m , or from about 12.5
2 2 2 2
mg/m to about 20 mg/m , or from about 14 mg/m to about 18 mg/m , or other rates, based
on the solids weight of the release aid and coated dryer surface area.
Other creping systems, methods, and adhesives are described in the following
U.S. Patents which are incorporated herein in their entireties by reference: 3,640,841;
4,304,625; 4,440,898; 4,788,243; 4,994,146; 5,025,046; 5,187,219; 5,326,434; 5,246,544;
,370,773; 5,487,813; 5,490,903; 5,633,309; 5,660,687; 5,846,380; 4,300,981; 4,063,995;
4,501,640; 4,528,316; 4,886,579; 5,179,150; 5,234,547; 5,374,334; 5,382,323; 5,468,796;
,902,862; 5,942,085; 5,944,954; 3,879,257; 4,684,439; 3,926,716; 4,883,564; 5,437,766.
The adhesives used according to the present invention can provide enhanced runnability and
reduced chatter. Creping with the pH modified adhesives according to the methods of the
present invention can enhance operational runnability because the adhesives retain their
adhesion over wide moisture and temperature ranges, and can be rewettable. As shown in the
examples, for example, the methods of the present invention are versatile enough to be used
on smaller diameter Yankee dryers operated at high running speeds. For example, the
methods can be applied to a Yankee dryer which has a diameter of less than about 15 feet, or
less than about 12 feet, or less than about 10 feet, or from about 5 feet to about 15 feet, or
from about 7.5 to 12 feet, or other diameters, with the Yankee dryer can be run at a speed of
from about 2000 feet/minute to about 3500 feet/minute, or from about 2200 feet/minute to
about 3200 feet/minute, or from about 2500 feet/minute to about 3000 feet/minute, or other
running speeds. As an option, because of the chemical setting of the creping adhesive
composition provided by methods of the present invention, the temperature of dryer surface
can be kept at lower values or reduced, for example, such as to from about 25°C to about
75°C, or to from about 35°C to about 60°C, or other values. Creped products produced using
the present methods and modified adhesives of the present invention, results in superior
creped tissue and towel products when compared to products made by systems and methods
that use conventional adhesives. The rewettability which adhesives of the present invention
can have, minimizes irreversible felt filling, minimizes deposit formation, and minimizes
clean-up time and efforts. The methods of using the pH modified adhesives according to the
present invention can enhance the creping performance in any type of tissue and towelling
process, including Yankee dryer processes, through-air dryer processes, and wet crepe tissue
machine processes.
The present invention includes, or described herein are, the following
aspects/embodiments/features in any order and/or in any combination:
1. A process for manufacturing a creped fiber web, comprising:
providing a rotating cylindrical dryer including a dryer surface;
providing a coating applicator fluidly connected to a supply or feed;
providing an adhesive base formulation in the supply or feed comprising a
crosslinkable polymer, wherein the adhesive base formulation has a first pH value, wherein
the first pH value is from about 3.5 to about 8.5;
adding a pH modifier to said adhesive base formulation to provide a creping adhesive
composition having a second pH value, wherein the second pH value is at least about 0.5 pH
units greater than the first pH value;
applying said creping adhesive composition to the dryer surface with the coating
applicator to provide an adhesive dryer surface;
conveying a fibrous web into contact with the adhesive dryer surface;
drying the fiber web on said adhesive dryer surface to form a dried fiber web; and
creping the dried fiber web from said adhesive dryer surface.
2. The process of any preceding or following embodiment/feature/aspect, wherein first
pH value is an acidic pH.
3. The process of any preceding or following embodiment/feature/aspect, wherein the
second pH value is a neutral or basic pH
4. The process of any preceding or following embodiment/feature/aspect, wherein the
second pH is a pH value of up to about 9.0.
. The process of any preceding or following embodiment/feature/aspect, wherein the
second pH value is a pH value of from about 7 to about 8.5.
6. The process of any preceding or following embodiment/feature/aspect, wherein the
adding of the pH modifier to said adhesive base formulation is effective for chemically
setting at least a portion of the crosslinkable polymer to form a crosslinked polymer before
the creping adhesive composition contacts the dryer surface.
7. The process of any preceding or following embodiment/feature/aspect, wherein the
rotating cylindrical dryer is a Yankee drum.
8. The process of any preceding or following embodiment/feature/aspect, wherein the
coating applicator comprises at least one sprayer for spraying the creping adhesive
composition onto the dryer surface.
9. The process of any preceding or following embodiment/feature/aspect, wherein said
coating applicator comprises a spray boom.
. The process of any preceding or following embodiment/feature/aspect, wherein pH
modifier is an inorganic alkali material, an inorganic alkaline earth material, an organic base,
or any combinations thereof.
11. The process of any preceding or following embodiment/feature/aspect, wherein the
pH modifier is an alkali metal hydroxide, an alkali metal oxide, an alkali metal phosphate, an
alkali metal carbonate, an alkali metal bicarbonate, an alkaline earth hydroxide, an alkaline
earth oxide, an alkaline earth phosphate, an alkaline earth carbonate, ammonium zirconium
carbonate, organotitanate, organozirconate, ammonium hydroxide, ammonium carbonate,
ammonium bicarbonate, alkali metal silicate, urea, substituted urea, a cyanate, an alkylamine,
an alkanolamine, a quaternary ammonium salt, a polyalkali metal pyrophosphate, salt of a
weak acid and a strong base, an alkaline buffering solution, or any combinations thereof.
12. The process of any preceding or following embodiment/feature/aspect, wherein pH
modifier is an alkali hydroxide, an alkaline earth hydroxide, a metal carbonate, an ammonium
zirconium carbonate, an organotitanate, an organozirconate, a polyalkali metal
pyrophosphate, or any combinations thereof.
13. The process of any preceding or following embodiment/feature/aspect, wherein said
adding of said pH modifier comprises introducing said pH modifier as a premixture with
water to a mixing vessel, to make-up water, to a feed going to a boom, or a return to a mixing
vessel, or any combination thereof.
14. The process of any preceding or following embodiment/feature/aspect, further
comprising introducing a release modifier to the adhesive base formulation.
. The process of any preceding or following embodiment/feature/aspect, wherein said
crosslinkable polymer comprises a crosslinkable cationic water-soluble polymer.
16. The process of any preceding or following embodiment/feature/aspect, wherein the
rotating cylindrical dryer has a diameter of less than about 15 feet and is run at a speed of
from about 2000 feet/minute to about 3500 feet/minute.
17. The process of any preceding or following embodiment/feature/aspect, wherein the
adhesive dryer surface is a cylindrical surface heated to a temperature of from about 90 °C to
about 110 °C.
18. The process of any preceding or following embodiment/feature/aspect, wherein
crosslinkable polymer is in an aqueous medium having an acidic pH.
19. The process of any preceding or following embodiment/feature/aspect, wherein said
adhesive base formulation further comprises a second cationic water-soluble polymer
different from the crosslinkable polymer.
. The process of any preceding or following embodiment/feature/aspect, wherein said
adhesive base formulation further comprises a release modifier.
21. The process of any preceding or following embodiment/feature/aspect, wherein said
creping adhesive composition comprises about 1 to 3% by weight said crosslinked polymer,
about 1 to 3% by weight release modifier, from about 0 to 1% by weight phosphate donor,
and from about 95% by weight to about 99% by weight water from all sources, by weight of
said composition.
22. The process of any preceding or following embodiment/feature/aspect, further
comprising drying said fiber web to a consistency of at least about 90% by weight before
creping said fiber web from said adhesive dryer surface.
23. A process of making creped fiber web, comprising:
increasing the pH of an adhesive base formulation that is to be used on a dryer
surface, wherein said adhesive base formulation comprises at least one crosslinkable
polymer, wherein the adhesive base formulation has a first pH value that is from about 4.5 to
about 8.5, and said increasing of the pH is by at least about 0.5 pH units greater than the first
pH value so as to form a creping adhesive composition.
24. The process of any preceding or following embodiment/feature/aspect, further
comprising:
applying said creping adhesive composition to the dryer surface.
. The process of any preceding or following embodiment/feature/aspect, further
comprising:
applying said creping adhesive composition to the dryer surface with a spray boom
and said increasing of the pH occurs in a mixing pot, in make-up water, or a feed line to said
spray boom, prior to said applying with the spray boom.
26. The process of any preceding or following embodiment/feature/aspect, further
comprising:
conveying a fibrous web into contact with the dryer surface having said creping
adhesive composition;
drying the fiber web to form a dried fiber web; and
creping the dried fiber web.
27. A method to increase the setting time of a creping adhesive that is applied on a dryer
surface, comprising increasing the pH of an adhesive base formulation that is to be used on
the dryer surface, wherein said adhesive base formulation comprises at least one
crosslinkable polymer, wherein the adhesive base formulation has a first pH value that is
from about 4.5 to about 8.5, and said increasing of the pH is by at least about 0.5 pH units
greater than the first pH value so as to form a creping adhesive composition.
28. A creped fiber product made from the process of any preceding or following
embodiment/feature/aspect.
29. The process of any preceding or following embodiment/feature/aspect, wherein the
first pH value is from 4.5 to 6 and the second pH value is from 6.1 to 8.5.
. The process of any preceding or following embodiment/feature/aspect, wherein the
firs pH value is increased by at least 2 pH units.
The present invention can include, or described herein is, any combination of
these various features or embodiments above and/or below as set forth in sentences and/or
paragraphs. Any combination of disclosed features herein is considered part of the present
description and no limitation is intended with respect to combinable features.
The present invention will be further clarified by the following examples, which
are intended to be exemplary of the present invention.
EXAMPLES
The following Examples described and results, such as shown in FIGS. 3 and
4, indicate the creping performance of a method using a pH modified adhesive formulation
used according to the present invention.
Example 1:
In this Example, an adhesive base formulation was prepared which contained a
polymer containing composition of CREPETROL® 5318, a commercial PAE creping
adhesive (Hercules Incorporated), and a release agent, BUSPERSE® 2097 (Buckman
Laboratories International Inc.), in an aqueous dispersion. An eight foot diameter Yankee
dryer was used for creping the towel fiber sheet, which dryer had a suction press roll.
Pressure on nozzle was approximately 108-110 psi, and running speed was adjusted from
about 2600 to about 2900 feet/minute (FPM). This machine was a semiwet crepe design with
a flat former. The fiber sheet had a moisture content of approximately 60-70 wt.% as
transferred to the Yankee dryer, and moisture content of approximately 15-20 wt.% when the
creped product was removed from the dryer. The Yankee dryer and reel speeds, in feet per
minute (FPM) units, pump setting, and the dryer hood temperature in degrees Fahrenheit
(°F), used in this study are indicated in the table in The adhesive was used at a
coating rate of about 3.5 mg/m and the release agent was used at about 10.6 mg/m . The
initial spray boom shower pH was 6.0. 10 wt.% NaOH solution was added to a recirculation
pot of the spray system to raise the pH of the adhesive formulation to about 8.0. At pH 6.0,
the machine speed was 2600 feet/minute (FPM) and after a couple of hours at 8.0 pH the
speed was successfully increased to 2900 FPM without coating streaking or chatter. The
dwell on this eight foot Yankee dryer was 39.7 milliseconds. At approximately 2900 FPM,
some wild edges (front) occurred. Addition of PROSOFT® TC9700 (Hercules Incorporated),
was added which prevented wild edges at the indicated higher speeds. At lower speeds, the
one adhesive was fully satisfactory. Visual observations by experienced technicians or
operators were used to evaluate the quality of the creping performance, such as in terms of
observing for coating edge buildup, streaking, and chatter. The running speeds were able to
be increased from about 2600 FPM to 2900 FPM without loss of creping performance by
only changing the pH of the boom shower. It was shown that the drying rates (reaction) for
the creping adhesive composition can be sped up without adverse streaking or chatter by
raising the pH of the creping adhesive composition at least 0.5 pH units.
Example 2:
A separate study was run on a 10 foot diameter Yankee dryer used for creping
napkin grade paper sheets, which has a 22.5 millisecond dwell. 10 wt.% NaOH solution was
fed into a mix pot. About 10 cc per minute of the caustic was added. A similar formulation
of adhesive and release agent as used in Example 1 was also used in this example. The fiber
sheet had a moisture content of approximately 60-70 wt.% as transferred to the Yankee dryer,
and moisture content of approximately 8-10 wt.% when the creped product was removed
from the dryer. The Yankee dryer and reel speeds, in feet per minute (FPM) units, pump
setting, and a Yankee temperature of 56°F, used in this study are indicated in the table in The initial pH was 5.9 and the caustic was added to increase the pH to about 7.6. The
amount of CREPETROL® 5318 adhesive coating rate was able to be reduced from 3.1
mg/m to 2.4 mg/m (about 20% reduction) without streaking or chatter while leaving the
release agent (BUSPERSE® 2097) amount unchanged at 15.7 mg/m . Visual observations by
experienced technicians or operators were used to evaluate the quality of the creping
performance, such as in terms of observing for coating edge buildup, streaking, and chatter.
Even at the reduced add-on rates for the pH modified adhesive, a constant bulk was able to be
maintained and an excellent Yankee coating was provided without adverse streaking or
chatter on this dry crepe machine. Blade wear was normal after 8 hours of operation.
Example 3:
A separate study was run on a 18-foot diameter Yankee dryer which handled
12# towel grade sheets at 12 wt.% to 14 wt.% moisture. 10 wt.% NaOH solution was fed
directly into the fresh water as it made up level in a mix pot. About 15-35 cc per minute of
the caustic was added. In this Example, an adhesive base formulation was prepared which
contained a polymer containing composition of BUBOND® 2624, a commercial modified
polyamine-type creping adhesive (Buckman Laboratories International Inc.), and a release
agent, BUSPERSE® 2097, in an aqueous dispersion. The fiber sheet had a moisture content
of approximately 65-70 wt.% as transferred to the Yankee dryer, and moisture content of
approximately 5-10 wt.% when the creped product was removed from the dryer. The Yankee
dryer speed was 4500-5500 FPM and the reel speed was 4000-4500 FPM. The Yankee
temperature was 180-210 °F and the pressure was 90-110 psi. The initial pH was 5-6.5 and
the caustic was added to increase the pH to about 7.8-8.8. The BUBOND® 2624 adhesive
coating rate used was about 2.0 to 6.0 mg/m . The BUSPERSE® 2097 coating rate was about
8-16 mg/m . Visual observations by experienced technicians or operators were used to
evaluate the quality of the creping performance, such as in terms of observing for coating
edge buildup, streaking, and chatter. Thickened film development and much more rapid cure
(setting) rates were observed without adverse streaking or chatter.
Example 4:
A separate study was run on a 10-foot diameter Yankee dryer which handled
8# lightweight grade sheets at 4-10 wt.% moisture. 10 wt.% NaOH solution was fed directly
into the fresh water as it made up level in a mix pot. About 5-20 cc per minute of the caustic
was added. In this Example, an adhesive base formulation was prepared which contained a
polymer containing composition of CREPETROL® 5318 and a release agent, BUSPERSE®
2097, in an aqueous dispersion. The fiber sheet had a moisture content of approximately 65-
75 wt.% as transferred to the Yankee dryer, and moisture content of approximately 6-10 wt.%
when the creped product was removed from the dryer. The Yankee dryer speed was 3000-
4000 FPM and the reel speed was 2500-3200 FPM. The Yankee temperature was 180-210 °F
and the pressure was 45 psi. The initial pH was 5.0-6.0 and the caustic was added to increase
the pH to about 7.5-8.5, at which the line was run for 4-5 hours. The BUSPERSE® 2097
coating rate was about 7-14 mg/m . The coating rate of CREPETROL® 5318 was able to be
reduced about 15% from about 3.0 mg/m to about 2.4 mg/m while maintaining visibly
better coating buildup and no adverse streaking or chatter.
Example 5:
A separate study was run on a Yankee dryer which handled 100% recycled
fiber (RF) towel grade sheets. In this Example, an adhesive base formulation was prepared
which contained a polymer containing composition of BUBOND® 2624 as a source of
crosslinkable polymer, and BUSPERSE® 2906 for coating build-up control, in an aqueous
dispersion. Cleaning and creping blades were loaded on the Yankee drum at 40 pounds per
linear inch (PLI). The fiber sheet moisture contents and other Yankee dryer equipment and
operating conditions were substantially similar to those described in Example 3. BUBOND®
2436, as a source of tetrapotassium pyrophosphate (60% TKPP in water), was added to the
adhesive base formulation at the spray boom before coating the resulting creping adhesive
composition on the drum. The dosage of BUBOND® 2436 add-on was varied between the
2 2 2 2
amounts of 0.4 mg/m , 2.0 mg/m , 4.3 mg/m , and 10 mg/m , with results observed for each
dosage. The initial pH of the adhesive base formulation before addition of BUBOND® 2436
was 3.5. The BUBOND® 2624 adhesive coating rate used was about 8 mg/m , and the
BUSPERSE® 2906 coating rate was about 2.5 mg/m . Visual observations by experienced
technicians were used to evaluate the quality of the creping performance, such as in terms of
observing for coating edge buildup, streaking, and corrugation. At a dosage of 0.4 mg/m
BUBOND® 2436, the spray boom adhesive pH was 3.5 and half of the roll did not pass
quality requirement for corrugation. At a dosage of 2.0 mg/m BUBOND® 2436, the spray
boom adhesive pH was 5.5 and corrugation became acceptable. At a dosage of 4.3 mg/m
BUBOND® 2436, the spray boom adhesive pH was 7.2 and at a dosage of 10.0 mg/m
BUBOND® 2436, the spray boom adhesive pH was about 7 and passed quality requirements
for creping performance.
Applicants specifically incorporate the entire contents of all cited references in
this disclosure. Further, when an amount, concentration, or other value or parameter is given
as either a range, preferred range, or a list of upper preferable values and lower preferable
values, this is to be understood as specifically disclosing all ranges formed from any pair of
any upper range limit or preferred value and any lower range limit or preferred value,
regardless of whether ranges are separately disclosed. Where a range of numerical values is
recited herein, unless otherwise stated, the range is intended to include the endpoints thereof,
and all integers and fractions within the range. It is not intended that the scope of the
invention be limited to the specific values recited when defining a range.
Other embodiments of the present invention will be apparent to those skilled
in the art from consideration of the present specification and practice of the present invention
disclosed herein. It is intended that the present specification and examples be considered as
exemplary only with a true scope and spirit of the invention being indicated by the following
claims and equivalents thereof.
Claims (25)
1. A process for manufacturing a creped fiber web, comprising: providing a rotating cylindrical dryer including a dryer surface; providing a coating applicator fluidly connected to a supply or feed; providing an adhesive base formulation in the supply or feed comprising a crosslinkable polymer, in an aqueous medium having an acidic pH, wherein the adhesive base formulation has a first pH value, wherein the first pH value is from about 3.5 to about 8.5; adding a pH modifier to said adhesive base formulation to provide a creping adhesive composition having a second pH value, wherein the second pH value is at least about 0.5 pH units greater than the first pH value, wherein said adding of said pH modifier comprises introducing said pH modifier as a premixture with water to a mixing vessel, to make-up water, to a feed going to a boom, or a return to a mixing vessel, or any combination thereof; applying said creping adhesive composition to the dryer surface with the coating applicator to provide an adhesive dryer surface; conveying a fibrous web into contact with the adhesive dryer surface; drying the fiber web on said adhesive dryer surface to form a dried fiber web; and creping the dried fiber web from said adhesive dryer surface, wherein the adding of the pH modifier to said adhesive base formulation is effective for chemically setting at least a portion of the crosslinkable polymer to form a crosslinked polymer before the creping adhesive composition contacts the dryer surface.
2. The process of claim 1, wherein first pH value is an acidic pH.
3. The process of claim 1 or 2, wherein the second pH value is a neutral or basic pH.
4. The process of any one of claims 1 to 3, wherein the second pH is a pH value of up to about 9.0.
5. The process of any one of claims 1 to 4, wherein the second pH value is a pH value of from about 7.0 to about 8.5.
6. The process of any one of claims 1 to 5, wherein the rotating cylindrical dryer is a Yankee drum.
7. The process of any one of claims 1 to 6, wherein the coating applicator comprises at least one sprayer for spraying the creping adhesive composition onto the dryer surface.
8. The process of any one of claims 1 to 7, wherein said coating applicator comprises a spray boom.
9. The process of any one of claims 1 to 8, wherein the pH modifier is an inorganic alkali material, an inorganic alkaline earth material, an organic base, or any combinations thereof.
10. The process of any one of claims 1 to 8, wherein the pH modifier is an alkali metal hydroxide, an alkali metal oxide, an alkali metal phosphate, an alkali metal carbonate, an alkali metal bicarbonate, an alkaline earth hydroxide, an alkaline earth oxide, an alkaline earth phosphate, an alkaline earth carbonate, ammonium zirconium carbonate, organotitanate, organozirconate, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, alkali metal silicate, urea, substituted urea, a cyanate, an alkylamine, an alkanolamine, a quaternary ammonium salt, a polyalkali metal pyrophosphate, salt of a weak acid and a strong base, an alkaline buffering solution, or any combinations thereof.
11. The process of any one of claims 1 to 8, wherein the pH modifier is an alkali hydroxide, an alkaline earth hydroxide, a metal carbonate, an ammonium zirconium carbonate, an organotitanate, an organozirconate, a polyalkali metal pyrophosphate, or any combinations thereof.
12. The process of any one of claims 1 to 11, further comprising introducing a release modifier to the adhesive base formulation.
13. The process of any one of claims 1 to 12, wherein said crosslinkable polymer comprises a crosslinkable cationic water-soluble polymer.
14. The process of any one of claims 1 to 13, wherein the rotating cylindrical dryer has a diameter of less than about 15 feet and is run at a speed of from about 2000 feet/minute to about 3500 feet/minute.
15. The process of any one of claims 1 to 14, wherein the adhesive dryer surface is a cylindrical surface heated to a temperature of from about 90 °C to about 110 °C.
16. The process of any one of claims 1 to 15, wherein said adhesive base formulation further comprises a second cationic water-soluble polymer different from the crosslinkable polymer.
17. The process of any one of claims 1 to 16, wherein said adhesive base formulation further comprises a release modifier.
18. The process of any one of claims 1 to 17, wherein said creping adhesive composition comprises about 1 to 3% by weight said crosslinked polymer, about 1 to 3% by weight release modifier, from about 0 to 1% by weight phosphate donor, and from about 95% by weight to about 99% by weight water from all sources, by weight of said composition.
19. The process of any one of claims 1 to 18, further comprising drying said fiber web to a consistency of at least about 90% by weight before creping said fiber web from said adhesive dryer surface.
20. The process of any one of claims 1 to 19, wherein the first pH value is from 4.5 to 6 and the second pH value is from 6.1 to 8.5.
21. The process of any one of claims 1 to 20, wherein the first pH value is increased by at least 2 pH units.
22. A process of making creped fiber web, comprising: increasing the pH of an adhesive base formulation that is to be used on a dryer surface, wherein said adhesive base formulation comprises at least one crosslinkable polymer, wherein the adhesive base formulation has a first pH value that is from about 4.5 to about 8.5, and said increasing of the pH is by at least about 0.5 pH units greater than the first pH value so as to form a creping adhesive composition; and applying said adhesive base formulation to the dryer surface with a spray boom wherein said increasing of the pH occurs in a mixing pot, make-up water, or a feed line to said spray boom prior to said applying with the spray boom; conveying a fibrous web into contact with the dryer surface having said adhesive base formulation; drying the fiber web to form a dried fiber web; and creping the dried fiber web, wherein adding a pH modifier to said adhesive base formulation is effective for chemically setting at least a portion of the crosslinkable polymer to form a crosslinked polymer before the adhesive base formulation contacts the dryer surface.
23. A creped fiber product made from the process of any one of claims 1 to 22.
24. A process of any one of claims 1 to 22 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figures.
25. A creped fiber product of claim 23 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figures.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201161513716P | 2011-08-01 | 2011-08-01 | |
US61/513,716 | 2011-08-01 | ||
PCT/US2012/048231 WO2013019526A1 (en) | 2011-08-01 | 2012-07-26 | Creping methods using ph-modified creping adhesive compositions |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ619657A NZ619657A (en) | 2015-09-25 |
NZ619657B2 true NZ619657B2 (en) | 2016-01-06 |
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