US2025207330A1PendingUtilityA1
Extruded starch and process of producing paper
Est. expiryApr 8, 2042(~15.7 yrs left)· nominal 20-yr term from priority
D21H 21/18D21F 11/00D21H 17/29D21H 17/28
60
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Claims
Abstract
A process of making paper includes providing a stock having fibrous material, extruded starch and optionally an inorganic filler. The stock is pressed to a minimum solids content before drying. The extruded starch may a) be cationic, b) be chemically or enzymatically modified c) be not cross linked, d) have a solubility in the range of 40-99%, c) have a molecular weight of over 300,000 Da, f) have a weight fraction over 30,000,000 Da of 0.05 or less and/or g) have an RVA viscosity of 15.000 cP or less. Feed starch is extruded with water. Optionally, one or more of a polyol, a humectant or a plasticizer, may be added. Optionally, chemical reagents or enzymes are used during extrusion to modify the starch. Optionally, the extrusion is performed substantially without a crosslinker. The extrusion may be done in a twin-screw extruder, optionally with one or more high shear sections.
Claims
exact text as granted — not AI-modified1 . A process of making paper comprising the steps of,
providing a stock, the stock comprising fibrous material, extruded starch, water and optionally one or more inorganic fillers; forming a paper web from the stock; pressing the paper web; and, drying the paper web, wherein the pressed paper web has solids content in wt % that is at least as much as a minimum solids content D(x) defined by formula (I):
D
(
x
)
=
46
+
(
x
-
10
)
*
0.3
(
I
)
wherein x is the ash content of the dry paper.
2 . The process of claim 1 wherein the ash content is determined according to ISO 1762:2019.
3 . The process of claim 1 wherein the paper has a weight in the range of 12-240 g/m 2 .
4 . The process of claim 1 comprising adding extruded starch to an aqueous suspension of the fibrous material.
5 . The process of claim 1 wherein the stock has a concentration of fibrous material in the range of 0.5 g/L to 15 g/L before draining the stock.
6 . The process of claim 5 comprising providing a thick stock at an initial concentration of fibrous material in the range of 0.5 g/L to 40 g/L, 10-40 g/L or 20-40 g/L and diluting the thick stock to concentration in the range of 0.5 g/L to 15 g/L.
7 . The process of claim 6 wherein the thick stock has a concentration of inorganic filler in the range of 0 to 20 g/L.
8 . The process of claim 1 wherein the extruded starch is present in the stock in a range of 0.05 to 5 wt %, or 0.06 to 2 wt %, relative to the weight of dry fibrous material.
9 . The process of claim 1 wherein the extruded starch is not crosslinked.
10 . The process of claim 1 wherein the extruded starch is crosslinked.
11 . The process of claim 1 wherein the extruded starch is cationic.
12 . The process of claim 1 , wherein the fibrous material comprises softwood fiber, hardwood fiber, non-wood fiber, or a combination thereof.
13 . The process of claim 1 , wherein the fibrous material comprises waste paper, market pulp, machine broke, recycled fiber, or a combination thereof.
14 . The process of claim 1 , wherein the inorganic filler comprises one or more pigments selected from the group consisting of metal oxides, silicates, carbonates, calcium carbonate, ground lime, chalk, marble (GCC), precipitated calcium carbonate (PCC), talc, kaolin, bentonite, satin white, calcium sulfate, barium sulfate and titanium dioxide.
15 . The process of claim 1 wherein at least a portion of the inorganic filler is provided as part of recycled fibrous material.
16 . The process of claim 1 , wherein the stock comprises one or more paper auxiliaries, optionally selected from the group consisting of: a sizing agent, a wet strength agent, a retention aid, a drainage aid, a dry strength enhancer, an optical brightener, a defoamer, a biocide, a paper dye, or a combination thereof.
17 . The process of claim 1 , wherein the paper has an ash content in the range of about 0 wt. % to about 40 wt. %.
18 . The process of claim 1 , wherein the extruded starch has one or more of the following attributes: the extruded starch is cationic; the extruded starch is not cross linked; the extruded starch has a solubility in the range of 40-99% or 40-93%; the extruded starch has a molecular weight of over 300,000 Da or over 500,000 Da or over 2,000,000 Da or 4,000,000 Da or more; the extruded starch has a molecular weight of 12,000,000 Da or less or 10,000,000 Da or less, or 8,000,000 Da or less; the extruded starch has a weight fraction (WF/dLog M) at 30,000,000 Da of 0.05 or less; the extruded starch has a cumulative weight fraction with a molecular weight of 1,000,000 Da or less, or 100,000 Da or less, in the range of 0-8% or 0-1%; the extruded starch has an RVA viscosity of 15,000 cP or less or 5,000 cP or less; and, the extruded starch is chemically or enzymatically modified during extrusion.
19 . A method of making a starch-containing product comprising the steps of,
treating starch-containing material in an extruder, or in another high shear and/or high specific mechanical energy environment, preferably using a twin screw extruder, optionally with one or more mixing and/or high shear sections, essentially without a crosslinker.
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30 . A starch-containing product having a molecular weight (Mw) of over 300,000 Da with one or more of: a) RVA viscosity of 15,000 cP or less at 20% solids, b) substantially no weight fraction over 30,000,000 Da (i.e. WF/d Log MW of 0.05 or less at 3*10 7 Da), c) a solubility in the range of 40-99%, d) a cumulative weight fraction with a molecular weight of 1,000,000 Da or less or 100,000 Da or less in the range of 0-8% or 0-1%, and e) Mw of 12,000,000 Da or less.
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37 . A process for production of paper, card and board, the process comprising draining paper stock comprising a mixture of paper fibers, inorganic fillers, water and at least one type of extruded starch, with sheet formation in the wire section further removal of water from the wet paper sheet by pressing the sheet in a press section and a final step of water removal by thermal treatment in a drying section to form a product, wherein:
the paper stock having a fibrous concentration in the range from 0.5 g/L to 40 g/L and an inorganic filler concentration in the range between 0 and 20 g/L, contains at least one type of starch dispersion obtained from an extruded starch, wherein before the paper making process, e.g., the first dewatering step, starts the paper stock containing the starch dispersion is diluted to a fibrous concentration in the range from 0.5 g/L to 15 g/L, wherein the diluted paper stock is then drained to form a sheet and the sheet is pressed in the press section to a solids content D(x) wt % or greater and D(x) computes according to
D
(
x
)
=
46
+
(
x
-
10
)
·
0.3
(
I
)
where x is the numerical value of inorganic filler content of the product (in wt %) and D(x) is the minimal solids content (in wt %) to which the sheet is pressed, wherein the extruded starch that provides the starch dispersion is obtained in a process where a feed starch is mixed with an aqueous liquid and where mechanical and thermal energy is applied by shear and/or additional heating in an extruder.
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