Paper making and fiber liberation – Processes and products – Non-uniform – irregular or configured web or sheet
Reexamination Certificate
2000-03-14
2002-03-05
Lovering, Richard D. (Department: 1712)
Paper making and fiber liberation
Processes and products
Non-uniform, irregular or configured web or sheet
C162S164300, C162S164400, C525S430000, C528S335000
Reexamination Certificate
active
06352613
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to resin compositions having high solids contents useful as wet strength resins and creping compositions.
2. Discussion of Background Information
In the papermaking industry, it is common to attempt to optimize papermaking compositions in order to provide specific functional properties as efficiently and economically as possible. Wet strength resins are a common additive to papermaking compositions. These materials act to provide strength to wet paper and are used in, among other paper products, paper towel and packaging. Among other uses, they are also useful as creping adhesives. Wet strength resins may be added during paper production to bind the cellulose fibers together, and to enhance the strength of the paper produced so that the paper does not fall apart when used under wet conditions. Such resins may be added to pulp and formed paper.
Commonly available wet strength resins are marketed under the brand name KYMEME® by Hercules Incorporated, Wilmington, Del. Attempts have been made to optimize such wet strength resins. Aqueous dispersions of such resins, having relatively high solids content, are desirable.
KYMENE 557H ® has long been a benchmark for strength additives in the papermaking industry. It is based on the reaction product of poly(adipic acid-co-diethylenetriamine) and epichlorohydrin. An excess of epichlorohydrin is used to control the rate of cross-linking during the manufacturing process and to aid in storage stability. Such compositions, and processes for their manufacture are disclosed in U.S. Pat. Nos. 2,926,116 and 2,926,154, both to KEIM and commonly assigned to Hercules Incorporated. These patents are incorporated by reference as though set forth in full herein.
Originally supplied as a 10% aqueous solution, the solids of such compositions were eventually raised to about 12.5%. A number of other wet strength resins were developed with improvements based on this initial chemistry. Examples of such improvements are disclosed in U.S. patent application Ser. No. 09/363,224 filed Jul. 30, 1999 and now abandoned commonly assigned to Hercules Incorporated, and hereby incorporated by reference as though set forth in full herein; U.S. Pat. No. 5,614,597 to BOWER, commonly assigned to Hercules Incorporated, and hereby incorporated by reference as though set forth in full herein, and U.S. Pat. Nos. 5,644,021 and 5,668,246, both to MASLANKA, also commonly assigned to Hercules Incorporated, and incorporated by reference as though set forth in full herein. Illustrative of such products are KYMENE 557LX® (which include advantages of reduced epichlorohydrin by-products); KYMENE ULX (which include advantages of very low levels of epichlorohydrin by-products) and KYMENE PLUS® (which exhibit 30% solids).
The provision of effective high solids resins has been a longstanding goal in the industry, both as a benefit to suppliers as well as to paper manufacturers. It is believed that KYMENE PLUS® is the highest solids polyamide-based product, at 30% solids.
It is particularly desirable to provide a resin that provides a high solids content, while also being equivalent to the KYMEME® resins.
It is also desirable to provide a resin that would offer a significant improvement in wet strength over, for example, KYMEME® 557H wet strength resin-carboxymethyl cellulose (CMC) combinations, that would have low epihalohydrin residual levels and that would be economically repulpable. This combination of a polyamidoamine-epihalohydrin resin and CMC generates a coacervate (semi-gelatinous mass) that improves resin retention and improves overall bonding of the resin with the cellulose fibers.
Further, it is desirable to provide such a resin that is also useful as a creping adhesive.
SUMMARY OF THE INVENTION
The invention provides polyamidoamine resins. The invention also provides aqueous dispersions of such resins, and, additionally, aqueous dispersions of wet strength resins which have high solids contents and favorable wet strengthening and/or adhesion properties. Compositions of the invention are useful as wet strength resins and as creping adhesives.
The resins of the invention provide advantages of ease of production
The resins of the invention also provide advantages of high solids contents and storage stability.
In preferred embodiments, the resins of the invention are based on water-soluble polyamidoamine resins having the structure(s) set forth in Formula I, below:
wherein:
R
1
is a substituted or unsubstituted hydrocarbon group;
R
2
is a substituted or unsubstituted hydrocarbon group;
R
3
is a substituted or unsubstituted hydrocarbon group; and
Z is halogen selected from F, Cl, Br and I, and combinations thereof.
The invention also relates to resin compositions containing such resins, and to methods of treating paper, paper products and cellulosic products and making paper products and cellulosic products using such resins and resin compositions.
The invention also comprises methods of preparing such resins. Such methods comprise:
reacting at least one polyamide having the structure
wherein
R
1
, R
2
, and R
3
are as defined above;
with at least one ammonium halide compound and at least one epihalohydrin compound having the structures:
wherein
Z is as defined above.
The invention also provides water-soluble polyamides prepared from such reactants.
The invention provides methods of increasing the wet strength of a cellulosic product comprising cellulose fibers comprising adding to one of the cellulose product or fibers such a water-soluble polyamidoamine resin.
The invention provides methods of creping a cellulosic product comprising cellulose fibers comprising adding to one of the cellulose product or fibers such a water-soluble polyamidoamine resin.
The invention provides a cellulosic product prepared by the foregoing methods.
In any of the foregoing, R
1
may be alkyl of from 1-6 C atoms, more preferably alkyl of 3-5 C atoms, more preferably 4 C atoms; R
2
may be alkyl of from 2-4 C atoms, more preferably alkyl of 2 C atoms; R
3
may be alkyl of from 2-4 C atoms, more preferably alkyl of 2 C atoms; x is from about 10 to about 30 mole % 15, more preferably about 25 mole %; more preferably about 20 mole %, and y is from about 70 to about 90 mole %, more preferably about 75 to about 85 mole %, more preferably about 80 mole %.
In any of the foregoing, the aqueous resin composition may preferably have a solids content of at least about 35%, more preferably about 50%, more preferably about 54%, more preferably about 55%.
In any of the foregoing, x may preferably be Cl.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is related to the discovery that compounds of Formula I
provide wet strength resins and creping adhesives which exhibit desirable properties, such as a high solids content when the resins are in the form of an aqueous dispersion. The invention is also directed to compounds of Formula (I) per se.
The invention provides significant advantages of ease of production, and in preferred embodiments, a combination of ease of production, high solids content and storage stability, which combination is highly unexpected.
Preferably, compounds of Formula I are prepared by reacting compounds of the following Formulae (II), (III) and (IV):
R
1
, R
2
and R
3
may be any substituted or unsubstituted hydrocarbon moiety of any length, which allows the compound of Formula (I) to be soluble in water. For example, R
1
, R
2
and R
3
can be straight or branched chain alkyl, alkenyl or alkynyl, cycloalkyl, cycloalkenyl, aromatic or other unsaturated cyclic compound, each of which may substituted or unsubstituted. In preferred embodiments, R
1
, is a substituted or unsubstituted hydrocarbon group selected from alkyl, alkenyl and alkynyl; and is preferably alkyl of from 1-6 C atoms, preferably 3-5 C atoms, more preferably 3-4 C atoms, and most preferably 4 C atoms; R
2
is a substituted or unsubstituted hydrocarbon group selected from alkyl, alkenyl and alkynyl; and is preferab
Hercules Incorporated
Lovering Richard D.
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