U.S. patent application number 13/899907 was filed with the patent office on 2013-10-10 for paper substrate containing a wetting agent and having improved printability.
The applicant listed for this patent is INTERNATIONAL PAPER COMPANY. Invention is credited to Yan C. Huang, Benjamin Thomas Liguzinski, David B. Shelmidine, Kapil M. Singh, Christopher Michael Wilson.
Application Number | 20130266746 13/899907 |
Document ID | / |
Family ID | 41404386 |
Filed Date | 2013-10-10 |
United States Patent
Application |
20130266746 |
Kind Code |
A1 |
Huang; Yan C. ; et
al. |
October 10, 2013 |
PAPER SUBSTRATE CONTAINING A WETTING AGENT AND HAVING IMPROVED
PRINTABILITY
Abstract
The present invention relates to a sizing composition that, when
applied to paper substrate, creates a substrate, preferably
suitable for inkjet printing, having increased print density, and
print mottle, as well as print sharpness, low HST, and/or image dry
time, the substrate preferably having high brightness and reduced
color-to-color bleed as well. In addition, the present invention
relates to a method of reducing the HST of a paper substrate by
applying the sizing composition to at least one surface thereof.
Further, the application relates to methods of making and using the
sizing composition, as well as methods of making and using the
paper containing the sizing composition.
Inventors: |
Huang; Yan C.; (Prescott
Valley, AZ) ; Singh; Kapil M.; (West Chester, OH)
; Shelmidine; David B.; (Ticonderoga, NY) ;
Liguzinski; Benjamin Thomas; (Cambridge, MA) ;
Wilson; Christopher Michael; (Middletown, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTERNATIONAL PAPER COMPANY |
Memphis |
TN |
US |
|
|
Family ID: |
41404386 |
Appl. No.: |
13/899907 |
Filed: |
May 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12572081 |
Oct 1, 2009 |
8460511 |
|
|
13899907 |
|
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61194875 |
Oct 1, 2008 |
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Current U.S.
Class: |
428/32.2 ;
162/181.1; 428/32.1; 428/32.18; 524/52 |
Current CPC
Class: |
D21H 17/28 20130101;
D21H 17/36 20130101; D21H 17/66 20130101; D21H 21/30 20130101; D21H
21/16 20130101; D21H 21/18 20130101; D21H 21/24 20130101 |
Class at
Publication: |
428/32.2 ;
162/181.1; 524/52; 428/32.1; 428/32.18 |
International
Class: |
D21H 21/16 20060101
D21H021/16 |
Claims
1. A sizing composition, comprising at least one binder; at least
one inorganic salt; and at least one wetting agent.
2. The sizing composition according to claim 1, comprising at least
two binders; at least one inorganic salt; and at least one wetting
agent.
3. The sizing composition according to claim 1, wherein the at
least two binders are polyvinyl alcohol and starch.
4. The sizing composition according to claim 1, wherein the total
binder is present at an amount ranging at least 20 wt %, based upon
the total weight of the solids in of the composition.
5. The sizing composition according to claim 1, further comprising
an optical brightening agent.
6. The sizing composition according to claim 5, wherein the optical
brightening agent is cationic.
7. The sizing composition according to claim 6, wherein the optical
brightening agent is a dye fixative.
8. The sizing composition according to claim 7, wherein the optical
brightening agent is present at an amount ranging from 1 to 5 wt %
based upon the total weight of the solids in of the
composition.
9. The sizing composition according to claim 1, comprising at least
one binder at an amount of at least 20 wt % based upon the total
weight of the solids in of the composition; at least one inorganic
salt at an amount ranging from 1 to 25 wt % based upon the total
weight of the solids in of the composition, and at least one
wetting agent at an amount ranging from 0.5 to 20 wt % based upon
the total weight of the solids.
10. The sizing composition according to claim 9, comprising at
least two binders wherein the at least two binders are starch and
polyvinyl alcohol; and an optical brightener.
11. A paper substrate, comprising the sizing composition according
to claim 1.
12. The paper substrate according to claim 11, wherein the
substrate has a print density of at least 0.95.
13. The paper substrate according to claim 11, wherein the
substrate has a waterfastness of at least 95%.
14. The paper substrate according to claim 11, wherein the
substrate has at least two surfaces, each of said surfaces having a
surface print mottle of less than 15.5 as measured by the print
non-uniformity index.
15. The paper substrate according to claim 11, wherein the
substrate has at least two surfaces, each of said surfaces having a
surface print mottle of less than 9.0 as measured by the print
non-uniformity index.
16. The paper substrate according to claim 15, wherein the
substrate has a print density of at least 1.0 and an HST of not
more than 10 seconds.
17. The paper substrate according to claim 16, wherein the
substrate has a waterfastness of at least 95%.
18. A method of making the paper substrate according to claim 11,
comprising contacting a sizing composition with a web of cellulose
fibers, wherein the sizing composition comprises at least one
binder, at least one inorganic salt, and at least one wetting
agent.
19. The method according to claim 18, wherein the contacting occurs
at the wet end, the size press, or the coater.
20. The method according to claim 19, comprising contacting the
sizing composition with the web at the size press an amount such
that from 50 to 110 lbs of binder is applied per ton of web, from
1.5 to 15 lbs of wetting agent is applied per ton of web, and from
5 to 30 lbs of inorganic salt is applied per ton of web.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a sizing composition that,
when applied to paper substrate, creates a substrate, preferably
suitable for inkjet printing, having increased print density, print
sharpness, low HST, and/or image dry time, the substrate preferably
having high brightness and reduced color-to-color bleed as well. In
addition, the present invention relates to a method of reducing the
HST of a paper substrate by applying the sizing composition to at
least one surface thereof. Further, the application relates to
methods of making and using the sizing composition, as well as
methods of making and using the paper containing the sizing
composition.
BACKGROUND OF THE INVENTION
[0002] Ink jet recording systems using aqueous inks are now well
known. These systems usually generate almost no noise and can
easily perform multicolor recordings for business, home and
commercial printing applications. Recording sheets for ink jet
recordings are known. See for example U.S. Pat. Nos. 5,270,103;
5,657,064; 5,760,809; 5,729,266; 4,792,487; 5,405,678; 4,636,409;
4,481,244; 4,496,629; 4,517,244; 5,190,805; 5,320,902; 4,425,405;
4,503,118; 5,163,973; 4,425,405; 5,013,603; 5,397,619; 4,478,910;
5,429,860; 5,457,486; 5,537,137; 5,314,747; 5,474,843; 4,908,240;
5,320,902; 4,740,420; 4,576,867; 4,446,174; 4,830,911; 4,554,181;
6,764,726 and 4,877,680, which are hereby incorporated, in their
entirety, herein by reference.
[0003] However, conventional paper substrates, such as those above
remain poor in balancing good print density, HST, color-to-color
bleed, print sharpness, and/or image dry time. Accordingly, there
is a need to provide such high-performance functionality to paper
substrates useful in inkjet printing, especially those substrates
preferably having high brightness.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1: A first schematic cross section of just one
exemplified embodiment of the paper substrate that is included in
the paper substrate of the present invention.
[0005] FIG. 2: A second schematic cross section of just one
exemplified embodiment of the paper substrate that is included in
the paper substrate of the present invention.
[0006] FIG. 3: A third schematic cross section of just one
exemplified embodiment of the paper substrate that is included in
the paper substrate of the present invention.
[0007] FIG. 4: Graphic illustration of print non-uniformity indexes
(a quantitative analysis of print mottle) of various paper
substrates described in Example 1.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The present inventors have discovered a sizing composition
that, when applied to paper or paperboard substrates, improves the
substrate's print density, print mottle, color-to-color bleed,
print sharpness, and/or image dry time. Further, the paper
substrate preferably has a high brightness.
[0009] The sizing composition may contain at least one wetting
agent (also known as surfactants and tensides). Examples of wetting
agents include those having an HLB value of from at least 2, and at
least 5 up to at most 15, at most 17, at most 18, and at most 20.
The HLB value of the wetting agent may be 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, including any and
all ranges and subranges contained therein. In one embodiment,
those wetting agents have a HLB value of from 3 to 10 are
sufficient. In another embodiment, those wetting agents having a
HLB value of from 12 to 20, more preferably 12-18, are sufficient.
Examples of wetting agents include, but are not limited to those
containing pyrrolidones such as for example caprylyl pyrrolidone,
and lauryl pyrrolidone. Examples of those are Easy-Wet.RTM.
commercially available from ISP Technologies. Further examples of
wetting agents include glycerol esters such as those commercially
available as Myverol.RTM.. These glycerol esters include glyceryl
monostearate, mixtures of glyceryl monostearate and glyceryl
monopalmitate (Myvaplex, Eastman Fine Chemical Company),
glycerylmonooleate, a mixture of mono, di and tri-glycerides (ATMUL
84S), glycerylmonolaurate, paraffin, white wax, long chain
carboxylic acids, long chain carboxylic acid esters, long chain
carboxylic acid alcohols, and mixtures thereof. The long chain
carboxylic acids can contain from 6 to 30 carbon atoms; in certain
embodiments at least 12 carbon atoms, and in other embodiments from
12 to 22 carbon atoms. In some embodiments this carbon chain is
fully saturated and unbranched, while others contain one or more
double bonds. In at least one embodiment the long chain carboxylic
acids contain 3-carbon rings or hydroxyl groups. Non-limiting
examples of saturated straight chain acids include n-dodecanoic
acid, n-tetradecanoic acid, n-hexadecanoic acid, caproic acid,
caprylic acid, capric acid, lauric acid, myristic acid, palmitic
acid, stearic acid, arachidic acid, behenic acid, montanic acid and
melissic acid. Also useful are unsaturated monoolefinic straight
chain monocarboxylic acids. Non-limiting examples of these include
oleic acid, gadoleic acid and erucic acid. Also useful are
unsaturated (polyolefinic) straight chain monocaboxyic acids.
Non-limiting examples of these include linoleic acid, linolenic
acid, arachidonic acid and behenolic acid. Useful branched acids
include, for example, diacetyl tartaric acid. Non-limiting examples
of long chain carboxylic acid esters include glyceryl
monostearates; glyceryl monopalmitates; mixtures of glyceryl
monostearate and glyceryl monopalmitate (Myvaplex 600, Eastman Fine
Chemical Company); glyceryl monolinoleate; glyceryl monooleate;
mixtures of glyceryl monopalmitate, glyceryl monostearate glyceryl
monooleate and glyceryl monolinoleate (Myverol 18-92 and Myverol
18-06 Eastman Fine Chemical Company); glyceryl monolinolenate;
glyceryl monogadoleate; mixtures of glyceryl monopalmitate,
glyceryl monostearate, glyceryl monooleate, glyceryl monolinoleate,
glyceryl monolinolenate and glyceryl monogadoleate (Myverol 18-99,
Eastman Fine Chemical Company); acetylated glycerides such as
distilled acetylated monoglycerides (Myvacet 5-07, 7-07 and 9-45,
Eastman Fine Chemical Company); mixtures of propylene glycol
monoesters, distilled monoglycerides, sodium stearoyl lactylate and
silicon dioxide (Myvatex TL, Eastman Fine Chemical Company);
mixtures of propylene glycol monoesters, distilled monoglycerides,
sodium stearoyl lactylate and silicon dioxide (Myvatex TL, Eastman
Fine Chemical Company) d-alpha tocopherol polyethylene glycol 1000
succinate (Vitamin E TPGS, Eastman Chemical Company); mixtures of
mono- and diglyceride esters such as Atmul (Humko Chemical Division
of Witco Chemical); calcium stearoyl lactylate; ethoxylated mono-
and di-glycerides; lactated mono- and di-glycerides; lactylate
carboxylic acid ester of glycerol and propylene glycol; lactylic
esters of long chain carboxylic acids; polyglycerol esters of long
chain carboxylic acids, propylene glycol mono- and di-esters of
long chain carboxylic acids; sodium stearoyl lactylate; sorbitan
monostearate; sorbitan monooleate; other sorbitan esters of long
chain carboxylic acids; succinylated monoglycerides; stearyl
monoglyceryl citrate; stearyl heptanoate; cetyl esters of waxes;
cetearyl octanoate; C10-C30 cholesterol/lavosterol esters; sucrose
long chain carboxylic acid esters; and mixtures thereof.
[0010] When the composition contains a wetting agent, the wetting
agent may be present in an amount ranging from at least 0.1 wt %,
at least 0.5 wt %, at least 1 wt %, and at least 2 wt %, and up to
at most 5 wt %, at most 10 wt %, and at most 20 wt % based upon the
total weight of the solids in of the composition. This amount of
wetting agent includes 0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 wt % based upon the
total weight of the solids in of the composition, including any and
all ranges and subranges contained therein. In one embodiment, the
composition contains from 0.5 to 10 wt % of wetting agent based
upon the total amount of the solids in of the composition.
[0011] The sizing composition may contain at least one inorganic
salt. Suitable inorganic salts may be monovalent and/or divalent
and/or trivalent and may contain any level of hydration complexes
thereof. Exemplified inorganic salts are those from Groups 1, 2 and
13 from the Periodic Table of Elements and hydrated complexes
thereof, including monohydrates, dihydrates, trihydrates,
tetrahydrates, etc. The cationic metal may be sodium, calcium,
magnesium, and aluminum preferably. The anionic counterion to the
cationic metal of the inorganic salt may be any halogen such as
chloride, boride, fluoride, etc and/or hydroxyl group(s). The most
preferred inorganic salt being sodium chloride.
[0012] The sizing composition may contain at least one inorganic
salt at any amount. When the sizing composition contains at least
one inorganic salt, the inorganic salt may be present at an amount
0.25 to 90 wt %, preferably from 0.25 to 25 wt % of the inorganic
salt based on the total weight of the solids in the composition.
This range may include 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5,
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85
and 90 wt % based on the total weight of the solids in the
composition, including any and all ranges and subranges contained
therein. In one embodiment the composition contains at least 5 wt %
of inorganic salt based on the total weight of the solids in the
composition.
[0013] The sizing composition may contain a binder. Examples of
binders include, but are not limited to, polyvinyl alcohol, Amres
(a Kymene type), Bayer Parez, polychloride emulsion, modified
starch such as hydroxyethyl starch, starch or derivatives thereof
including cationic and oxidized forms and from corn and/or potato
for example, polyacrylamide, modified polyacrylamide, polyol,
polyol carbonyl adduct, ethanedial/polyol condensate, polyamide,
epichlorohydrin, glyoxal, glyoxal urea, ethanedial, aliphatic
polyisocyanate, isocyanate, 1,6 hexamethylene diisocyanate,
diisocyanate, polyisocyanate, polyester, polyester resin,
polyacrylate, polyacrylate resin, acrylate, and methacrylate. While
any combination of binders may be used, one embodiment includes a
sizing composition containing starch or modifications thereof
combined with polyvinyl alcohol as multi-component binder.
[0014] When there is a multicomponent binder system, one embodiment
relates to a system including at least starch and deriviates
thereof with polyvinyl alcohol. In this embodiment, the ratio of
starch/PVOH solids based on the total weight of the solids in the
sizing composition may be any ratio so long as both are present in
the composition. The sizing composition may contain a ratio of
starch/PVOH wt % solids based on the total weight of the solids in
the composition of from 99/1 to 1/99, preferably from 50/1 to 1/5,
more preferably at most 10/1 to 1:2, most preferably at most 8/1 to
1/1. This range includes 99/1, 50/1, 25/1, 15/1, 10/1, 9/1, 8/1,
7/1, 6/1, 5/1, 4/1, 3/1, 2/1, 1/1, 2/3, 1/2, 1/10, 1/25, 1/50,
1/99, including any and all ranges and subranges therein. The most
preferred starch/PVOH ratio being 6/1.
[0015] When polyvinyl alcohol is utilized in the sizing solution
and/or in the paper, polyvinyl alcohol (PVOH) is produced by
hydrolyzing polyvinyl acetate (PVA). The acetate groups are
replaced with alcohol groups and the higher the hydrolysis
indicates that more acetate groups have been replaced. Lower
hydrolysis/molecular weight PVOH are less viscous and more water
soluble. The PVOH may have a % hydrolysis ranging from 100% to 75%.
The % hydrolysis may be 75, 76, 78, 80, 82, 84, 85, 86, 88, 90, 92,
94, 95, 96, 98, and 100% hydrolysis, %, including any and all
ranges and subranges therein. Preferably, the % hydrolysis of the
PVOH is greater than 90%.
[0016] The sizing composition may contain a binder at any amount.
The sizing composition may contain at least one binder from 0 to 99
wt %, preferably at least 10 wt %, at least 40 wt %, and/or at
least 50 wt % based on the total weight of the solids in the
composition. This range may include 0, 1, 5, 10, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100 wt % based on
the total weight of the solids in the composition, including any
and all ranges and subranges contained therein. In one embodiment,
the composition may contain from 65 to 85 wt % of binder based on
the total weight of the solids in the composition.
[0017] The sizing composition may contain at least one optical
brightening agent (OBA). Suitable OBAs may be those mentioned in
U.S. Ser. No. 60/654,712 filed Feb. 19, 2005, and U.S. Pat. No.
6,890,454, which are hereby incorporated, in their entirety, herein
by reference. The OBAs may be commercially available from Clariant.
Further, the OBA may be either cationic and/or anionic. Example OBA
is that commercially available Leucophore BCW and Leucophore FTS
from Clariant. In one embodiment, the OBA contained in the sizing
composition is cationic. In another embodiment, the OBA may be also
act as a dye fixative. An example of a dye fixative that is in the
form of a complex with an OBA or that may also act as an OBA is
that which is commercially available from Clariant as Leucophor
FTS. Further examples of such dye fixative/OBA dual function
compounds and/or formulations include those when the OBA is
cationic rather than anionic. Still further, examples can be found
in U.S. Pat. Nos. 7,060,201 and 6,890,454, which is hereby
incorporated, in its entirety, herein by reference.
[0018] The sizing composition may contain any amount of at least
one anionic OBA. The sizing composition may contain anionic OBA at
an amount from 0 to 99 wt %, from 5 to 75 wt %, from 10 to 50 wt %,
from 20 to 40 wt % based on the total weight of the solids in the
composition. This range may include 0, 1, 5, 10, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 99 wt % anionic OBA
based on the total weight of the solids in the composition,
including any and all ranges and subranges contained therein. In
one embodiment, the composition may contain from 1 to 10 wt %, from
2 to 5 wt % of anionic OBA based on the total weight of the solids
in the composition
[0019] The sizing composition may contain any amount of at least
one cationic OBA. The sizing composition may contain cationic OBA
at an amount from 0 to 99 wt %, preferably from 0.5 to 25 wt %,
from 1 to 20 wt %, and from 2 to 10 wt % based on the total weight
of the solids in the composition. This range may include 0, 1, 5,
10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90,
99 wt % cationic OBA based on the total weight of the solids in the
composition, including any and all ranges and subranges contained
therein. In one embodiment, the composition may contain from 1 to
10 wt %, from 2 to 5 wt % of cationic OBA based on the total weight
of the solids in the composition
[0020] The composition may also contain a crosslinking agent. The
crosslinking agent may be any chemical that is capable of
crosslinking the hydroxyl groups of starch and/or the functional
groups of the dye fixative. The crosslinking agent may be
formaldehyde, urea, formaldehyde/urea resins, melamine,
formaldehyde/melamine resins, acid anhydrides, maleic anhydride,
anhydrides, metal salts, boron-containing compounds, boron
containing salts, metal containing boron compounds, borates, sodium
borate, ammonium salts, zirconium salts, AZT, glyoxal, blocked
glyoxal such as those commercially available from Clariant (known
as Cartabond TSI). Examples of blocked glyoxals are those that have
the reactive groups either sterically or chemically blocked so that
such groups may not react until a temperature of the compound is
reached. While this temperature could be any temperature, in some
circumstances the temperature could be greater than 150.degree.
Farenheit or even at least 160.degree. Farenheit.
[0021] The sizing composition may contain any amount of at least
one crosslinking agent. The sizing composition may contain at least
one crosslinking agent at an amount from 0 to 99 wt %, from 0.25 to
25 wt %, from 0.5 to 10 wt %, and from 0.75 to 2 wt % based on the
total weight of the solids in the composition. This range may
include 0, 0.25, 0.5, 0.75, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 99 wt % crosslinking agent
based on the total weight of the solids in the composition,
including any and all ranges and subranges contained therein.
[0022] The sizing composition may or may not contain a pigment.
Examples of pigments are clay, calcium carbonate, calcium sulfate
hemihydrate, and calcium sulfate dehydrate, calcium carbonate,
preferably precipitated calcium carbonate, in any form including
ground calcium carbonate and silica-treated calcium carbonate. When
the pigment is a calcium carbonate, it may be in any form. Examples
include ground calcium carbonate and/or precipitated calcium
carbonate.
[0023] The pigment may have any surface area. Those pigments having
a high surface area are included, including those having a surface
area of greater than 20 square meters/gram, preferably greater than
30 square meters/gram, more preferably greater than 50 square
meters/gram, most preferably greater than 100 square meters/gram.
This range includes greater than or equal to 1, 5, 10, 15, 20, 25,
30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100 square
meters/gram, including any and all ranges and subranges contained
therein.
[0024] The sizing composition may contain a pigment at any amount.
The composition may less than 15 wt %, less than 10 wt %, and less
than 5 wt % pigment based upon the total weight of the solids in
the composition. This range may include less than 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, and 15 wt % of pigment based upon the total weight of
the solids in the composition, including any and all ranges and
subranges contained therein. In one embodiment, the composition
does not contain pigment or does not contain substantial amounts of
pigment. Thus, the composition may contain trace amounts of
pigment, but preferably as little as possible.
[0025] The sizing composition may contain at least one nitrogen
containing organic species acting as a dye fixative. Exemplified
nitrogen containing organic species are compounds, oligomers and
polymers are those containing one or more quaternary ammonium
functional groups. Such functional groups may vary widely and
include substituted and unsubstituted amines, imines, amides,
urethanes, quaternary ammonium groups, dicyandiamides and the like.
Illustrative of such materials are polyamines, polyethyleneimines,
polymers and copolymers of diallyldimethyl ammonium chloride
(DADMAC), copolymers of vinyl pyrrolidone (VP) with quaternized
diethylaminoethylmethacrylate (DEAMEMA), polyamides, cationic
polyurethane latex, cationic polyvinyl alcohol, polyalkylamines
dicyandiamid copolymers, amine glycigyl addition polymers,
polyoxyethylene (dimethyliminio) ethylene (dimethyliminio)
ethylene] dichlorides. Examples of nitrogen containing species
include those mentioned in U.S. Pat. No. 6,764,726, which is hereby
incorporated, in its entirety, herein by reference. The most
preferred nitrogen containing species are polymers and copolymers
of diallyldimethyl ammonium chloride (DADMAC).
[0026] The sizing composition may contain at least one nitrogen
containing organic species at any amount. The sizing composition
may contain the nitrogen containing species at an amount ranging
from 0.5 to 50 wt %, from 1 to 20 wt %, and from 2 to 10 wt % based
on the total weight of the solids in the composition. This range
may include 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30,
35, 40, 45, and 50 wt % based on the total weight of the solids in
the composition, including any and all ranges and subranges
contained therein. In one embodiment, the composition does not
contain a nitrogen containing organic species or does not contain
substantial amounts of a nitrogen containing organic species. Thus,
the composition may contain trace amounts of a nitrogen containing
organic species, but preferably as little as possible. The present
invention also relates to a paper substrate containing any of the
sizing compositions described above.
[0027] The paper substrate contains a web of cellulose fibers. The
source of the fibers may be from any fibrous plant. The paper
substrate of the present invention may contain recycled fibers
and/or virgin fibers. Recycled fibers differ from virgin fibers in
that the fibers have gone through the drying process at least
once.
[0028] The paper substrate of the present invention may contain
from 1 to 99 wt %, preferably from 5 to 95 wt %, most preferably
from 60 to 80 wt % of cellulose fibers based upon the total weight
of the substrate, including 1, 5, 10, 15, 20, 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 99 wt %, and including
any and all ranges and subranges therein.
[0029] While the fiber source may be any, the preferable sources of
the cellulose fibers are from softwood and/or hardwood. The paper
substrate of the present invention may contain from 1 to 100 wt %,
preferably from 5 to 95 wt %, cellulose fibers originating from
softwood species based upon the total amount of cellulose fibers in
the paper substrate. This range includes 1, 2, 5, 10, 15, 20, 25,
30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 wt
%, including any and all ranges and subranges therein, based upon
the total amount of cellulose fibers in the paper substrate.
[0030] The paper substrate of the present invention may contain
from 1 to 100 wt %, preferably from 5 to 95 wt %, cellulose fibers
originating from hardwood species based upon the total amount of
cellulose fibers in the paper substrate. This range includes 1, 2,
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,
90, 95, and 100 wt %, including any and all ranges and subranges
therein, based upon the total amount of cellulose fibers in the
paper substrate.
[0031] When the paper substrate contains both hardwood and softwood
fibers, it is preferable that the hardwood/softwood ratio be from
0.001 to 1000. This range may include 0.001, 0.002, 0.005, 0.01,
0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500,
600, 700, 800, 900, and 1000 including any and all ranges and
subranges therein and well as any ranges and subranges therein the
inverse of such ratios.
[0032] Further, the softwood and/or hardwood fibers contained by
the paper substrate of the present invention may be modified by
physical and/or chemical means. Examples of physical means include,
but is not limited to, electromagnetic and mechanical means. Means
for electrical modification include, but are not limited to, means
involving contacting the fibers with an electromagnetic energy
source such as light and/or electrical current. Means for
mechanical modification include, but are not limited to, means
involving contacting an inanimate object with the fibers. Examples
of such inanimate objects include those with sharp and/or dull
edges. Such means also involve, for example, cutting, kneading,
pounding, impaling, etc means.
[0033] Examples of chemical means include, but is not limited to,
conventional chemical fiber modification means including
crosslinking and precipitation of complexes thereon. Examples of
such modification of fibers may be, but is not limited to, those
found in the following patents 6,592,717, 6,592,712, 6,582,557,
6,579,415, 6,579,414, 6,506,282, 6,471,824, 6,361,651, 6,146,494,
H1,704, 5,731,080, 5,698,688, 5,698,074, 5,667,637, 5,662,773,
5,531,728, 5,443,899, 5,360,420, 5,266,250, 5,209,953, 5,160,789,
5,049,235, 4,986,882, 4,496,427, 4,431,481, 4,174,417, 4,166,894,
4,075,136, and 4,022,965, which are hereby incorporated, in their
entirety, herein by reference. Further modification of fibers is
found in United States patent applications having Application No.
60/654,712 filed Feb. 19, 2005; Ser. Nos. 11/358,543 filed Feb. 21,
2006; 11/445,809 filed Jun. 2, 2006; and 11/446,421 filed Jun. 2,
2006, which may include the addition of optical brighteners (i.e.
OBAs) as discussed therein, which are hereby incorporated, in their
entirety, herein by reference.
[0034] One example of a recycled fiber is a "fine". Sources of
"fines" may be found in SaveAll fibers, recirculated streams,
reject streams, waste fiber streams. The amount of "fines" present
in the paper substrate can be modified by tailoring the rate at
which such streams are added to the paper making process.
[0035] The paper substrate preferably contains a combination of
hardwood fibers, softwood fibers and "fines" fibers. "Fines" fibers
are, as discussed above, recirculated and are any length. Fines may
typically be not more that 100 .mu.m in length on average,
preferably not more than 90 .mu.m, more preferably not more than 80
.mu.m in length, and most preferably not more than 75 .mu.m in
length. The length of the fines are preferably not more than 5, 10,
15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,
and 100 .mu.m in length, including any and all ranges and subranges
therein.
[0036] The paper substrate may contain fines at any amount. The
paper substrate may contain from 0.01 to 100 wt % fines, preferably
from 0.01 to 50 wt %, most preferably from 0.01 to 15 wt % based
upon the total weight of the fibers contained by the paper
substrate. The paper substrate contains not more than 0.01, 0.05,
0.1, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100 wt %
fines based upon the total weight of the fibers contained by the
paper substrate, including any and all ranges and subranges
therein.
[0037] The paper substrate may also contain an internal sizing
and/or external sizing composition. The internal sizing composition
may be applied to the fibers during papermaking at the wet end,
while the external sizing composition may be applied to the fibers
via a size press and/or coater. The above mentioned sizing
compositions of the present invention may be the internal and/or
external sizing composition contained by the paper substrate of the
present invention.
[0038] FIGS. 1-3 demonstrate different embodiments of the paper
substrate 1 in the paper substrate of the present invention. FIG. 1
demonstrates a paper substrate 1 that has a web of cellulose fibers
3 and a sizing composition 2 where the sizing composition 2 has
minimal interpenetration of the web of cellulose fibers 3. Such an
embodiment may be made, for example, when a sizing composition is
coated onto a web of cellulose fibers.
[0039] FIG. 2 demonstrates a paper substrate 1 that has a web of
cellulose fibers 3 and a sizing composition 2 where the sizing
composition 2 interpenetrates the web of cellulose fibers 3. The
interpenetration layer 4 of the paper substrate 1 defines a region
in which at least the sizing solution penetrates into and is among
the cellulose fibers. The interpenetration layer may be from 1 to
99% of the entire cross section of at least a portion of the paper
substrate, including 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50,
55, 60, 65, 70, 75, 80, 85, 90, 95, and 99% of the paper substrate,
including any and all ranges and subranges therein. Such an
embodiment may be made, for example, when a sizing composition is
added to the cellulose fibers prior to a coating method and may be
combined with a subsequent coating method if required. Addition
points may be at the size press, for example.
[0040] FIG. 3 demonstrates a paper substrate 1 that has a web of
cellulose fibers 3 and a sizing solution 2 where the sizing
composition 2 is approximately evenly distributed throughout the
web of cellulose fibers 3. Such an embodiment may be made, for
example, when a sizing composition is added to the cellulose fibers
prior to a coating method and may be combined with a subsequent
coating method if required. Exemplified addition points may be at
the wet end of the paper making process, the thin stock, and the
thick stock.
[0041] The paper substrate may be made by contacting any component
of the sizing solution with the cellulose fibers consecutively
and/or simultaneously. Still further, the contacting may occur at
acceptable concentration levels that provide the paper substrate of
the present invention to contain any of the above-mentioned amounts
of cellulose and components of the sizing solution. The contacting
may occur anytime in the papermaking process including, but not
limited to the thick stock, thin stock, head box, and coater with
the preferred addition point being at the thin stock. Further
addition points include machine chest, stuff box, and suction of
the fan pump. Preferably, the components of the sizing solution are
preformulated either together and/or in combination within a single
and/or separate coating layer(s) and coated onto the fibrous web
via a size press and/or coater.
[0042] The paper or paperboard of this invention can be prepared
using known conventional techniques. Methods and apparatuses for
forming and making and applying a coating formulation to a paper
substrate are well known in the paper and paperboard art. See for
example, G. A. Smook referenced above and references cited therein
all of which is hereby incorporated by reference. All such known
methods can be used in the practice of this invention and will not
be described in detail.
[0043] The paper substrate may contain the sizing composition at
any amount. The paper substrate may contain the sizing composition
at an amount ranging from 70 to 300 lbs/ton of paper, preferably
from 80 to 250 lbs/ton of paper, more preferably from 100 to 200
lbs/ton of paper, most preferably from 115 to 175 lbs/ton of paper.
This range includes, 70, 80, 90, 100, 110, 120, 130, 135, 140, 150,
160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270 280,
290, and 300 lbs/ton of paper, including any and all ranges and
subranges therein. In a preferred embodiment the paper substrate
contains a size press applied sizing composition at an amount of
from 110 to 150 lbs/ton of paper substrate.
[0044] Given the above mentioned preferred amounts of sizing
composition contained in the substrate of the present invention,
combined with the above-mentioned amounts of binder, inorganic
salt, OBA and wetting agent; the amounts of each of the binder,
inorganic salt, OBA and wetting agent that are contained in the
paper may be easily calculated. For example, if 50 wt % of binder
is present in the sizing solution based upon the total weight of
solids in the composition, and the paper substrate contains 150 lbs
of the sizing composition/ton, then the paper substrate contains
50%.times.150 lbs/ton of paper=75 lbs binder/ton of paper, which is
75 lbs/2000 lbs.times.100=3.75 wt % binder based upon the total
weight of the paper substrate.
[0045] The paper substrate contains any amount of at least one
wetting agent. The paper substrate may contain from 0.001 wt % to 5
wt %, from 0.01 to 2.5 wt %, from 0.02 to 1 wt %, and from 0.05 to
0.5 wt % of wetting agent based upon the total weight of the
substrate. This range includes 0.001, 0.002, 0.005, 0.007, 0.01,
0.02, 0.03, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5,
0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8,
3, 3.5, 4, and 5 wt % of wetting agent based upon the total weight
of the substrate, including any and all ranges and subranges
therein.
[0046] The paper substrate contains any amount of at least
inorganic salt. The paper substrate may contain from 1 wt % to 20
wt %, from 2 to 10 wt %, 3 to 8 wt % of inorganic salt based upon
the total weight of the substrate. This range includes at least 1,
2, 3.5, 4, 5, 5.5, 6, 7, 7.5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, and 20 wt % of inorganic salt based upon the total weight
of the substrate, including any and all ranges and subranges
therein.
[0047] The paper substrate contains any amount of at least one
binder. The paper substrate may contain from 0.1 wt % to 10 wt %,
from 1 to 7 wt %, and from 2 to 5 wt % based upon the total weight
of the substrate. This range includes 0.1, 0.2, 0.3, 0.4, 0.5, 1,
1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 9, and 10
wt % of binder based upon the total weight of the substrate,
including any and all ranges and subranges therein.
[0048] The paper substrate may contain any amount of OBA. The OBA
may be cationic and/or anionic. The OBA may be supplied by the
sizing composition as mentioned above and/or within the substrate
itself. For example, the OBA may be premixed with the fibers at the
wet end of the papermaking and even before the headbox. Preferred
examples of using OBA:fiber mixes is found in United States patent
applications having application Ser. Nos. 11/358,543 filed Feb. 21,
2006; 11/445,809 filed Jun. 2, 2006; and 11/446,421 filed Jun. 2,
2006, which are hereby incorporated, in their entirety, herein by
reference.
[0049] In one embodiment of the present invention, the paper
substrate contains internal OBA and externally applied OBA. The
internal OBA may be cationic or anionic, but is preferably anionic.
The externally applied OBA may be cationic or anionic, but is
preferably cationic. The externally applied OBA is preferably
applied as a member of the sizing composition at the size press as
mentioned above in the above preferred amounts of OBA. However,
external OBA may also be applied at the coating section.
[0050] In one embodiment when the OBA is a cationic OBA, the paper
substrate contains from 1 to 10 wt % of externally applied OBA
based upon the total weight of the paper. This range includes 1, 2,
3, 4, 5, 6, 7, 8, 9 and 10 wt % of OBA based upon the total weight
of the substrate, including any and all ranges and subranges
therein.
[0051] The paper substrate of the present invention may have any
amount of OBA. In one embodiment, the OBA is present in as
sufficient amount so that the paper has at least 80% GE brightness.
The GE brightness is preferably at least 80, 85, 90, 91, 92, 93,
94, 95, 96, 97, 98, 99, and 100%, including any and all ranges and
subranges contained therein.
[0052] Further, the paper may have a suitable amount of OBA and
other additives (such as dyes) so that the paper preferably has a
CIE whiteness of at least 130. The CIE whiteness may be at least
130, 135, 140, 145, 150, 155, 160, 65, 170, 175, 180, 185, 190,
195, and 200 CIE whiteness points, including any and all ranges and
subranges therein.
[0053] In one embodiment, the substrate contains an effective
amount of OBA. An effective amount of OBA is such that the GE
brightness is at least 90, preferably at least 92, more preferably
at least 94 and most preferably at least 95% brightness. The OBA
may be a mixture of the above-mentioned internal and externally
applied OBA, whether cationic and/or anionic so long as it is an
effective amount.
[0054] The density, basis weight and caliper of the web of this
invention may vary widely and conventional basis weights, densities
and calipers may be employed depending on the paper-based product
formed from the web. Paper or paperboard of invention preferably
have a final caliper, after calendering of the paper, and any
nipping or pressing such as may be associated with subsequent
coating of from about 1 mils to about 35 mils although the caliper
can be outside of this range if desired. More preferably the
caliper is from about 4 mils to about 20 mils, and most preferably
from about 7 mils to about 17 mils. The caliper of the paper
substrate with or without any coating may be 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 17, 20, 22, 25, 27, 30, 32, and 35,
including any and all ranges and subranges therein.
[0055] Paper substrates of the invention preferably exhibit basis
weights of from about 10 lb/3000 ft.sup.2 to about 500 lb/3000
ft.sup.2, although web basis weight can be outside of this range if
desired. More preferably the basis weight is from about 30 lb/3000
ft.sup.2 to about 200 lb/3000 ft.sup.2, and most preferably from
about 35 lb/3000 ft.sup.2 to about 150 lb/3000 ft.sup.2. The basis
weight may be 10, 12, 15, 17, 20, 22, 25, 30, 32, 35, 37, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140,
150, 160, 170, 180, 190, 200, 225, 250, 275, 300, 325, 350, 375,
400, 425, 450, 500 lb/3000 ft.sup.2, including any and all ranges
and subranges therein.
[0056] The final density of the papers may be calculated by any of
the above-mentioned basis weights divided by any of the
above-mentioned calipers, including any and all ranges and
subranges therein. Preferably, the final density of the papers,
that is, the basis weight divided by the caliper, is preferably
from about 6 lb/3000 ft.sup.2/mil to about 14 lb/3000 ft.sup.2/mil
although web densities can be outside of this range if desired.
More preferably the web density is from about 7 lb/3000
ft.sup.2/mil to about 13 lb/3000 ft.sup.2/mil and most preferably
from about 9 lb/3000 ft.sup.2/mil to about 12 lb/3000
ft.sup.2/mil.
[0057] The web may also include other conventional additives such
as, for example, starch, expandable microspheres, mineral fillers,
bulking agents, sizing agents, retention aids, internal sizing
agents, external sizing agents, and strengthening polymers. Among
the fillers that may be used are organic and inorganic pigments
such as, by way of example, polymeric particles such as polystyrene
latexes and polymethylmethacrylate, and minerals such as calcium
carbonate, kaolin, and talc. Other conventional additives include,
but are not restricted to, wet strength resins, internal sizes, dry
strength resins, alum, fillers, pigments and dyes. Internal sizing
helps prevent the surface size from soaking into the sheet, thus
allowing it to remain on the surface where it has maximum
effectiveness. The internal sizing agents encompass any of those
commonly used at the wet end of a paper machine. These include
rosin sizes, ketene dimers and multimers, and alkenylsuccinic
anhydrides. The internal sizes are generally used at levels of from
about 0.00 wt. % to about 0.25 wt. % based on the weight of the dry
paper sheet. Methods and materials utilized for internal sizing
with rosin are discussed by E. Strazdins in The Sizing of Paper,
Second Edition, edited by W. F. Reynolds, Tappi Press, 1989, pages
1-33. Suitable ketene dimers for internal sizing are disclosed in
U.S. Pat. No. 4,279,794, which is incorporated by reference in its
entirety, and in United Kingdom Patent Nos. 786,543; 903,416;
1,373,788 and 1,533, 434, and in European Patent Application
Publication No. 0666368 A3. Ketene dimers are commercially
available, as Aquapel.RTM. and Precis.RTM. sizing agents from
Hercules Incorporated, Wilmington, Del. Ketene multimers for use in
internal sizes are described in: European Patent Application
Publication No. 0629741A1, corresponding to U.S. patent application
Ser. No. 08/254,813, filed Jun. 6, 1994; European Patent
Application Publication No. 0666368A3, corresponding to U.S. patent
application Ser. No. 08/192,570, filed Feb. 7, 1994; and U.S.
patent application Ser. No. 08/601,113, filed Feb. 16, 1996.
Alkenylsuccinic anhydrides for internal sizing are disclosed in
U.S. Pat. No. 4,040,900, which in incorporated herein by reference
in its entirety, and by C. E. Farley and R. B. Wasser in The Sizing
of Paper, Second Edition, edited by W. F. Reynolds, Tappi Press,
1989, pages 51-62. A variety of alkenylsuccinic anhydrides are
commercially available from Albemarle Corporation, Baton Rouge, La.
Internal sizing agents may also be applied externally.
[0058] The paper substrate may be made by contacting further
optional substances with the cellulose fibers as well. The
contacting of the optional substances and the cellulose fibers may
occur anytime in the papermaking process including, but not limited
to the thick stock, thin stock, head box, size press, water box,
and coater. Further addition points include machine chest, stuff
box, and suction of the fan pump. The cellulose fibers, components
of the sizing composition, and/or optional components may be
contacted serially, consecutively, and/or simultaneously in any
combination with each other. The cellulose fibers components of the
sizing composition may be pre-mixed in any combination before
addition to or during the paper-making process.
[0059] The paper substrate may be pressed in a press section
containing one or more nips. However, any pressing means commonly
known in the art of papermaking may be utilized. The nips may be,
but is not limited to, single felted, double felted, roll, and
extended nip in the presses. However, any nip commonly known in the
art of papermaking may be utilized.
[0060] The paper substrate may be dried in a drying section. Any
drying means commonly known in the art of papermaking may be
utilized. The drying section may include and contain a drying can,
cylinder drying, Condebelt drying, IR, or other drying means and
mechanisms known in the art. The paper substrate may be dried so as
to contain any selected amount of water. Preferably, the substrate
is dried to contain less than or equal to 10% water.
[0061] The paper substrate may be passed through a size press,
where any sizing means commonly known in the art of papermaking is
acceptable. The size press, for example, may be a puddle mode size
press (e.g. inclined, vertical, horizontal) or metered size press
(e.g. blade metered, rod metered). At the size press, sizing agents
such as binders may be contacted with the substrate. Optionally
these same sizing agents may be added at the wet end of the
papermaking process as needed. After sizing, the paper substrate
may or may not be dried again according to the above-mentioned
exemplified means and other commonly known drying means in the art
of papermaking. The paper substrate may be dried so as to contain
any selected amount of water. Preferably, the substrate is dried to
contain less than or equal to 10% water. Preferably, the sizing
apparatus is a puddle size press.
[0062] The paper substrate may be calendered by any commonly known
calendaring means in the art of papermaking. More specifically, one
could utilize, for example, wet stack calendering, dry stack
calendering, steel nip calendaring, hot soft calendaring or
extended nip calendering, etc. While not wishing to be bound by
theory, it is thought that the presence of the expandable
microspheres and/or composition and/or particle of the present
invention may reduce and alleviate requirements for harsh
calendaring means and environments for certain paper substrates,
dependent on the intended use thereof.
[0063] The paper substrate may be microfinished according to any
microfinishing means commonly known in the art of papermaking.
Microfinishing is a means involving frictional processes to finish
surfaces of the paper substrate. The paper substrate may be
microfinished with or without a calendering means applied thereto
consecutively and/or simultaneously. Examples of microfinishing
means can be found in United States Published Patent Application
20040123966 and references cited therein, which are all hereby, in
their entirety, herein incorporated by reference.
[0064] The Hercules Sizing Test Value ("HST") of the substrate is
selected to provide the desired waterfastness characteristics. The
HST is measured using the procedure of TAPPI 530 pm-89. The paper
substrate of the present invention may have any HST. In some
embodiments, the HST may be as much as 400, 300, 200, and 100
seconds. Further, the HST may be is as low as 0.1, 1, 5 and 10
seconds. However, in a preferred embodiment of this invention, the
HST is less than 10 seconds, preferably, less than 5 seconds, more
preferably less than 3 seconds HST, most preferably less than about
1 second. The HST may be 0.001, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2,
2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 and 10
seconds, including any and all ranges and subranges therein. As it
is well known to those of ordinary skill in the art, the HST will
vary directly with the basic weight of the substrate and other
factors known to those of ordinary skill in the art. Based upon the
foregoing information, one of ordinary skill in the art can use
conventional techniques and procedures to calculate, determine
and/or estimate a particular HST for the substrate used to provide
the desired image waterfastness characteristics.
[0065] The paper substrate of the present invention may have any
black optical density as measured by TAPPI METHOD T 1213 sp-03. The
black optical density may be from 0.5 to 2.0, more preferably from
1.0 to 1.5. The black optical density may be 0.5, 0.6, 0.7, 0.8,
0.9, 1.0, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13,
1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.2, 1.3, 1.4, and 1.5,
including any and all ranges and subranges therein.
[0066] From density, one can naturally calculate waterfastness
using the following equation:
(OD of soaked ink area/OD of unsoaked ink area)*100=%
Waterfastness.
The paper substrate of the present invention may have any
waterfastness. The paper substrate may have a waterfastness of at
least 90%, preferably at least 95%, more preferably greater than
98%, most preferably greater than 100%, including any and all
ranges and subranges therein.
[0067] In an embodiment of the present invention, a paper substrate
may having at least one surface, preferably at least two surfaces,
having an improved print mottle. The print mottle of at least one
surface may be less than 20, preferably less than 9.0, most
preferably less than 8.5 on at least one side of the substrate.
Print mottle may be measured as disclosed in United States
Published Applications 20070044929 and 20060060317, which are
hereby incorporated, in their entirety, herein by reference. Print
mottle may also be measured by the Print Non-Uniformity Index which
includes printing an image on a substrate, using Adobe PhotoShop's
histogram to graph the intensity of dark and light pixels within a
uniform color within the image. A standard deviation is calculated
by Adobe Photoshop's histogram tool. Accordingly, a high standard
deviation indicates an increase as the number of shades within in
an image increase. Accordingly, the steps to calculate the print
mottle as a function of the Print Non-Uniformity measurement is: 1)
Scan an image into Adobe Photoshop at 600 dpi; 2) Select the solid
uniform color area of the image that you want to test using
Photoshop's marquee tool. The size of the area should be as large
as possible without going outside the solid image area. Open the
histogram window and set the channel to Luminosity. The standard
deviation value can then be plotted, compared, and contrasted with
other paper substrates containing the same image and having the
same histogram plotted over the same portion of the same image.
[0068] The print mottle of the substrate may be improved by 3%,
preferably 5%, more preferably 7%, and most preferably by 10%
compared to that of conventional paper substrates, especially those
conventional substrates when not containing wetting agents. A
preferred improvement in the print mottle is in the range or from 3
to 7%, more preferably from 5 to 15%, most preferably at least 20%
compared to that of conventional paper substrates, especially those
conventional substrates when not containing wetting agents.
[0069] The present invention is explained in more detail with the
aid of the following embodiment example which is not intended to
limit the scope of the present invention in any manner.
EXAMPLES
Example 1
[0070] No pigment is present in the compositions of this example.
This example employs a wetting agent in a size press
formulation/composition to provide the inkjet (IJ) recording media
with new and improved end-use performance.
GLOSSARY
[0071] Substrate: typical commodity grade of an IJ recording media
for commercial, web-fed, high-speed IJ presses. The substrate is 60
lbs/3300 square feet. Ziegler 650: high quality commercial grade IJ
recording media for commercial, web-fed, high-speed IJ presses.
Substrate+Wetting Agent 2 (1%)+CaCl2: this is an inventive example
and is high quality commercial grade of an IJ recording media for
commercial, web-fed, high-speed IJ presses and offset pre-printable
Wetting Agent 1: commonly used wetting agent, glycerol ester type.
Myverol 18-06 is the actual used. Wetting Agent 2: aliphatic
pyrrolidone type. International Specialty Products (ISP) Easy-Wet
20 was used. % of wetting agent: based on the amount of starch in
the size press formulation, e.g., 1% means 1 lb of the wetting
agent per 100 lbs of starch in the size press formulation CaCl2:
For the two CaCl2-containing conditions, each has 15 lbs/ton in it.
Photoshop Print Non-Uniformity Index: as described above.
TABLE-US-00001 TABLE 1 Formulations in the example: starch Cargill
Leucophor Cartabond Wetting Wetting 235D FTS TSI Agent 1 Agent 2
CaCl2 (lbs/ton) (lbs/ton) (lbs/ton) (lbs/ton) (lbs/ton) (lbs/ton)
substrate 90 2 1 0 0 0 substrate + WettingAgt#1(10%) 90 2 1 9 0 0
substrate + WettingAgt#1(10%) + CaCl2 90 2 1 9 0 15 substrate +
WettingAgt#2(1%) 90 2 1 0 1 0 substrate + WettingAgt#2(1%) + CaCl2
90 2 1 0 1 15 Ziegler 650 (commercial product)
About 120 lbs/ton of the formulations above were added to the
substrate via a puddle size press. The Photoshop Print
Non-Uniformity Index of each of the examples were measured and
plotted in FIG. 4. From FIG. 4, both wetting agents improve print
uniformity. Further, wetting agent 2 is more effective as 1%
thereof is equivalent of the effect of 10% of wetting agent 1. Both
wetting agents are compatible with inorganic salts such as calcium
chloride. Wetting agent 2 has an additional advantage to even
further lower the print non-uniformity than wetting agent 1. The
formulations of this invention which includes wetting agent 1
and/or 2 matches or is better than the performance of a commercial
paper substrate, i.e. Ziegler 650 that does not contain the
composition of the present invention. Thus, Ziegler 650 is not
offset pre-printable, but the paper substrates of the present
invention are offset pre-printable.
[0072] Numerous modifications and variations on the present
invention are possible in light of the above teachings. It is,
therefore, to be understood that within the scope of the
accompanying claims, the invention may be practiced otherwise than
as specifically described herein.
[0073] As used throughout, ranges are used as a short hand for
describing each and every value that is within the range, including
all subranges therein.
All of the references, as well as their cited references, cited
herein are hereby incorporated by reference with respect to
relative portions related to the subject matter of the present
invention and all of its embodiments.
* * * * *