Paper making and fiber liberation – Processes and products – Non-fiber additive
Reexamination Certificate
2000-06-12
2002-08-13
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Processes and products
Non-fiber additive
C162S179000, C162S164100, C162S168100, C106S243000, C106S287230, C106S287250
Reexamination Certificate
active
06432269
ABSTRACT:
BACKGROUND OF THE INVENTION
Alkaline paper differs from acid paper in that some alkaline paper contains internal sizing (added to the wood pulp rather than to surface of the paper), such as, alkyl succinic anhydride (ASA), to prevent rewetting of the paper. However, certain conventional opacifiers such as mixtures of the mono- and di-stearamides of amino ethyl ethanol amine, tend to react with the ASA sizing which prevents the sizing from functioning. As a result, the paper absorbs water.
It would be desirable to have an opacifier for alkaline paper which does not react with alkyl succinic anhydride.
SUMMARY OF THE INVENTION
The present invention provides a novel opacifier and opacifying composition for use with alkaline paper which does not react with alkyl succinic anhydride. The opacifier comprises a mixture of: an aromatic polymer, preferably an aromatic acrylic polymer or an aromatic anhydride polymer, more preferably a styrene acrylic polymer or a styrene maleic anhydride polymer; and a stearamide. The stearamide preferably comprises either a mono-stearamide or a di-stearamide of an ethanol amine, more preferably the stearamide comprises both a mono-stearamide and a di-stearamide of an ethanol amine, preferably an amino ethyl ethanol amine. Preferably the opacifier comprises from 5% to 60%, more preferably from 15% to 50%, most preferably from 30% to 40% aromatic polymer and preferably from 40% to 95%, more preferably from 50% to 85%, most preferably from 60% to 70% of the stearamide.
Preferably the opacifying composition comprises from 0.01% to 100%, more preferably from 2 to 50%, even more preferably from 3% to 40%, most preferably from 5% to 35%, opacifier; and from 0% to 99.99%, preferably from 0.001 to 99.99%, more preferably from 50% to 98%, even more preferably from 60% to 97% water; most preferably from 65% to 95% water. The water is preferably present in an effective amount to emulsify the opacifier and thus to provide the opacifying composition in a liquid, emulsion form. A base is preferably present in an effective amount to provide the opacifying composition with a pH greater than 7.5. The base is preferably present in an effective amount to provide the opacifying composition with a pH of from 7.5 to 11.0. In a embodiment where water is employed, the opacifying composition is preferably an emulsion.
When the opacifying composition is added to the alkaline wood pulp, the paper produced therefrom has the desired opacity, brightness and non-absorbency. The inventions also relate to paper, methods of enhancing optical properties of paper and to methods of making the novel opacifying compositions.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a novel opacifying composition for use with alkaline paper which does not react with alkyl succinic anhydride. As used herein, “paper” means a matted or felted sheet of fiber. Preferably the fiber is cellulose. The opacifying composition comprises a mixture of an aromatic polymer, preferably a styrene acrylic polymer, and a stearamide which preferably comprises a mono-stearamide or a di-stearamide of amino ethyl ethanol amine. Most preferably the stearamide comprises both a mono-stearamide or a di-stearamide of amino ethyl ethanol amine. Preferably the opacifier comprises from 5% to 60%, more preferably from 15% to 50% , most preferably from 30% to 40% aromatic polymer and preferably from 40% to 95%, more preferably from 50% to 85%, most preferably from 60% to 70% of the stearamide.
Preferably the opacifying composition comprises from 1% to 100%, more preferably from 2 to 50%, even more preferably from 3% to 40%, most preferably from 5% to 35%, opacifier, and from 0% to 99%, more preferably from 0.001 to 99%, even more preferably from 50% to 98%, most preferably from 60% to 97% water. The water is preferably present in an effective amount to provide the opacifying composition in a liquid, emulsion form. Thus, the opacifying composition may be in solid form comprising primarily the opacifier, or in liquid form comprising water and the opacifier.
A base is preferably present in an effective amount to provide the opacifying composition with a pH greater than 7.5. The base is preferably present in an effective amount to provide the opacifying composition with a pH of from 7.5 to 11.0.
When the opacifying composition is added to the alkaline 25 wood pulp, the paper produced therefrom has the desired opacity, brightness and non-absorbency. As used herein, “alkaline wood pulp” means the wood pulp has a pH of from 6.5 to 9.0.
The Aromatic Polymer
The aromatic polymer is preferably an aromatic acrylic polymer or an aromatic anyhdride polymer, preferably a styrene acrylic polymer, or a styrene maleic anhydride resin. Preferably the aromatic polymer has a molecular weight of from 500 to 16,500.
The Aromatic Acrylic Polymer
Preferably the aromatic acrylic polymer has a weight average molecular weight of from 4,000 to 16,500 more preferably from 7,000 to 10,000, most preferably from 7,500 to 9,000. Preferably the styrene acrylic polymer has a softening point from 53° C. to 300° C., more preferably 70° C. to 250° C., most preferably from 90° C. to 185° C., an acid number preferably from 40 to 280, more preferably from 100 to 260, most preferably from 150 to 230, a density of preferably from 1.05 to 1.6, more preferably from 1.09 to 1.5, most preferably from 1.1 to 1.2, and a glass transition temperature of preferably from 40° C. to 140° C., more preferably from 45° C. to 130° C., most preferably from 65° C. to 105° C.
Preferably the aromatic acrylic polymer is a styrene acrylic polymer. A suitable styrene acrylic polymer has a weight average molecular weight of 8,000 and is commercially available under the tradename Morez 101 from Morton. A suitable styrene acrylic polymer has a weight average molecular weight of 8,500, an acid number of 215, a softening point of 165° C., a glass transition temperature of 85° C., and a density of 1.13 and is commercially available under the trade name Joncryl 678 from Johnson Polymer.
The Aromatic Anhydride Resin
The aromatic anyhdride resin preferably has a weight average molecular weight of 500 to 10,000. The aromatic anhydride resin is a copolymer of a substituted aromatic ring and an anhydride, preferably a copolymer of styrene and maleic anhydride and the esters and salts thereof, preferably having aromatic:anhydride ratio of from 1 to 3:1. Preferably the aromatic anhydride has a melting point range of from 45-180° C., more preferably 100-175° C., most preferably from 150-170° C. Preferably the aromatic anhydride has an acid number of from 100 to 500, more preferably from 106 to 490, most preferably from 350 to 485 and preferably a 15% NVM viscosity of from 10 to 60, more preferably 12 to 26, most preferably 15 to 20 cP at 30° C.
Preferably the aromatic anhydride resin is a styrene maleic anhydride resin. A suitable styrene maleic anhydride resin is a styrene maleic anhydride copolymer, having a weight average molecular weight of 8,000, a melting point range of 150-170° C., and acid number of 480 a 15% NVM viscosity of 17 cP at 30° C. and a styrene: maleic anhydride ratio of 1:1, a Gardner color of 1-2, and is commercially available under the trade name SMA® 1000 from Atochem North America Inc.
The Stearamide
The stearamide has the following general structure:
wherein:
m is an integer from 0-1;
n is either an integer from 11 to 23; preferably from 15 to 17;
o is an integer from 0-1;
R
1
is a hydrogen;
R
2
is an alkyl group having from 1 to 15 carbon atoms preferably 2 to 6 carbon atoms;
R
3
is an aliphatic alcohol group having from 1 to 15 carbon atoms preferably 2 to 6 carbon atoms;
and R
4
is
wherein p is an integer from 11 to 23, preferably 15 to 17.
Preferably the stearamide comprises either a monostearamide or a di-stearamide or a mixture of both. Preferably the stearamide comprises from 1% to 50%, more preferably from 10% to 30% of at least one mono-stearamide; and from 50% to 99%, more preferably from 70% to 90% of at least one di-stearamide. Preferably the mono-st
Chin Peter
Golrick Mary E.
Omnova Solutions Inc.
Rywalski Robert F.
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