Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2000-04-05
2002-05-14
Seidleck, James J. (Department: 1711)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S3550RA, C428S3550CP, C428S906000, C524S001000, C524S027000, C524S047000, C524S048000, C524S080000, C106S285000
Reexamination Certificate
active
06387475
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to water based adhesive compositions having good release properties as well as adhesion, stiffness and strength properties making it useful in paper applications such as tissue and towels requiring release properties and coreless paper rolls. More particularly, this invention involves an aqueous adhesive composition comprising a water based adhesive and a substituted dicarboxylic acid anhydride starch derivative as a release agent.
Starches and dextrins have long been used as adhesive materials in various applications such as the fabrication of corrugated boards, paper bags, paper boxes, laminated paperboard, spiral-wound tubes, gummed labels, gummed tapes and other gumming applications. Disclosure of these and other applications may be found in “Starch Chemistry and Technology”, Second Edition, edited by R. Whistler et al., 1984, pp. 593-610 and “Starch and its Modifications”, Chapter 22, by M. W. Rutenberg, pp. 22-68 to 22-70 in “Handbook of Water-Soluble Gums and Resins”, edited by Robert L. Davidson, 1980.
Typical adhesives categories include liquid adhesives, pastes, cold water soluble adhesives and water resistant adhesives and provide properties such as tack, adhesives, solution viscosity and stability. While starch adhesives have been used in such applications, they generally do not provide release properties. Typically, separate release agents and coatings are used and they comprise materials such as silicones and waxes.
Now it has been found that a water based adhesive, such as starch adhesive composition in accordance with this invention, provides good release properties in addition to adhesion, stiffness and strength properties. This unusual combination of properties makes this composition particularly suitable in paper applications requiring release and strength properties such as needed in tissue and towel applications. Also this composition has been found suitable for use in coreless paper rolls where stiffness and strength as well as release properties are important characteristics. The nature of the adhesive as a starch material which is biodegradable and environmentally friendly also makes it attractive in paper applications where repulpability and recyclability are desired. Other possible applications for this adhesive-release composition include folding cartons, coupons or labels, envelopes and cigarette packaging.
SUMMARY OF THE INVENTION
Now it has been found that an adhesive composition with good release properties is provided by an aqueous composition comprising a water based adhesive and a substituted dicarboxylic acid anhydride starch derivative as a release agent.
More particularly, this invention is directed to an aqueous adhesive composition with good release properties comprising:
a) a water soluble polymer having a viscosity of less than about 25,000 cPs at a temperature of about 22° C. and a solids of 10% or more, and
b) an effective amount of a release agent having the formula:
where St is starch, R is a dimethylene or trimethylene group, R′ is a substituent hydrocarbon having 8 to 18 carbon atoms, M is a polyvalent metal and x is an integer equal to the valence of M.
This invention also involves an in-situ method of preparing the water based adhesive composition as described above wherein:
a) a water soluble polymer is dispered in water,
b) a substituted dicarboxylic acid anhydride starch derivative having the following formula is added to the polymer solution,
where St is the starch base material, R is a dimethylene or trimethylene group, R′ is a substituent hydrocarbon group having 8 to 18 carbon atoms and Y is alkali metal or ammonium, and
c) multivalent metal activator is added and dissolved in the solution.
DETAILED DESCRIPTION OF THE INVENTION
The adhesive-release composition of this invention comprises a water soluble polymer or polysaccharide adhesive in combination with a metal activated substituted dicarboxylic acid anhydride starch derivative as a release agent.
The water soluble polymer material useful as the adhesive component may be any polysaccharide including starch, dextrin, cellulose and gums, as well as polyvinyl alcohol and resins. Particularly useful are the starches and dextrins including any of the several starches, native, converted or derivatized, Such starches include those derived from any plant source including corn, potato, wheat, rice, sago, tapioca, waxy maize, sorghum and high amylose starch such as high amylose corn, i.e. starch having at least 45% amylose content by weight. Starch flours may also be used. Also included are the conversion products derived from any of the former bases, such as, for example, dextrins prepared by hydrolytic action of acid and/or heat; fluidity or thin boiling starches prepared by enzyme conversion or mild acid hydrolysis; oxidized starches prepared by treatment with oxidants such as sodium hypochlorite; and derivatized or modified starches such as cationic, anionic, amphoteric, non-ionic, crosslinked and hydroxypropyl starches. Other useful polysaccharides are cellulose materials such as carboxymethylcellulose, hydroxypropyl cellulose and hydroxypropyl methylcellulose, and gums such as guar, xanthan, pectin and carrageenan. Also useful polymers are polyvinyl alcohol, polyacrylic acid and protein materials such as animal glue as well as resins and resin emulsions such as polyvinyl acetate and ethylvinyl acetate.
The water soluble adhesive component will suitably have a viscosity of less than about 25,000 cPs at room temperature (about 22° C.) and a solids content of less than about 25,000 cPs at room temperature (about 22° C.) and a solids content of at least 10%, more particularly about 10 to 80%, and preferably a viscosity of from about 500 to 2,000 cPs and a solids of at least 30%, more particularly about 30 to 50%.
The release agent or fugitive adhesive additive as used in this invention is a material having the formula:
where St is starch, R is a dimethylene or trimethylene group, R′ is a substituent hydrocarbon having 8 to 18 carbons, M is a polyvalent metal and x is an integer equal to the valence of M. More particularly, R is a dimethylene group and R′ is a hydrocarbon group having 8 to 12 carbons. The hydrocarbon substituent group R′ may be an alkyl, alkenyl, aryl, aralkyl, or aralkenyl group, preferably an alkyl or alkenyl and more preferably alkenyl. M is a polyvalent or multivalent metal with a valence of 2 or more, such as calcium, aluminum, magnesium, iron, zinc and antimony with calcium and aluminum being preferred. The amount of derivative group on or bound to the starch, i.e.
will be from about 0.5 to 25% and preferably from about 1 to 10% by weight based on the weight of dry starch. Any of the starches can be used in preparing the release agent as described above. This includes any of the native, converted, modified or derivatized starches. Such starches include those derived from any plant source including corn, potato, wheat, rice, sago, tapioca, waxy maize, sorghum and high amylose starch such as high amylose corn, i.e. starch having at least 45% amylose content by weight. Starch flours may also be used. Also included are the conversion products derived from any of the former bases, such as, for example, dextrins prepared by hydrolytic action of acid and/or heat; fluidity or thin boiling starches prepared by treatment with oxidants such as sodium hypochlorite; and derivatized or modified starches such as cationic, anionic, amphoteric, non-ionic, crosslinked and hydroxypropyl starches.
The preparation of hydrocarbon substituted starch derivatives is known and described in U.S. Pat. No. 2,661,349 issued Dec. 1, 1953 to C. Caldwell et al. and also in “Starch: Chemistry and Technology”, Second Edition, edited by R. L. Whistler et al., 1984, pp. 341-343 and “Modified Starches: Properties and Uses”, edited by O. Wurzburg, 1986, Chapter 9, pp. 131-147. An improved method for preparing the hydrocarbon or hydrophobic derivative is disclosed in U.S. Pat. 5,672,699 issued on Sep. 30, 199
Billmers Robert L.
Figiel Edmund W.
Foulke Cynthia L.
National Starch and Chemical Investment Holding Corporation
Ribar Travis B
Seidleck James J.
LandOfFree
Water based adhesive composition with release properties does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water based adhesive composition with release properties, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water based adhesive composition with release properties will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2862525