Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-09-28
2003-07-01
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C525S186000, C525S187000, C525S430000, C525S438000
Reexamination Certificate
active
06586512
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to superabsorbent polymer compositions and their use in absorbent articles.
Superabsorbent polymers are well-known materials that commonly are used in personal care articles such as diapers. These polymers are known to absorb several times their weight of, for example, water, saline solution, urine, blood, and serous bodily fluids. Fixation or containment of superabsorbent polymer particles within an absorbent device is important to producers of absorbent personal-care devices. This containment reduces particle shakeout in these devices. Particle shakeout can result in loss of containment of the particle in the device and subsequent contact of the particle with a user's skin. Particle shakeout also results in redistribution of the particles within the device, potentially causing performance problems with the device.
It would be desirable to have an improved solution to the problem of particle shakeout in personal-care devices, cable wrap components, and other applications where particle shakeout is a problem.
SUMMARY OF THE INVENTION
The present invention includes such a solution in the form of a process comprising contacting a substrate with a superabsorbent polymer and a binding amount of a hydroxy-functionalized polyether. This process reduces the shakeout of a superabsorbent polymer from an absorbent article. In another aspect, the invention is a composition comprising a superabsorbent polymer and a hydroxy-functionalized polyether. Surprisingly, the polyether can be employed at very low concentrations to give good adhesion of the superabsorbent polymer to the substrate. In another embodiment, the polyether is employed as part of a hot-melt adhesive composition further optionally comprising a compatible tackifier, a compatible plasticizer and a compatible diluent.
The compositions of the present invention may be employed in a wide variety of uses known in the art, such as, for example, the assembly or construction of cable wrap components and various disposable absorbent articles, such as sanitary napkins, disposable diapers, hospital gowns, bed pads and the like.
DETAILED DESCRIPTION OF THE INVENTION
The process, composition and article of manufacture of the invention employ a superabsorbent polymer and a hydroxy-functionalized polyether (HFPE).
The polyether advantageously is employed in an amount sufficient to bind the superabsorbent polymer of the invention to a substrate. Preferably, the polyether is employed in an amount that is from 0.01 to 20 weight percent of the total weight of polyether and superabsorbent polymer. More preferably, the amount of polyether is from 0.1 to 10 weight percent, even more preferably the amount is from 0.15 to 4 weight percent, and most preferably the amount of polyether is from 0.25 to 2 weight percent. Preferably, the amount of polyether is at least 0.01 weight percent, based on the weight of polyether and superabsorbent polymer, more preferably is at least 0.1 weight percent, even more preferably is at least about 0.15 weight percent, and most preferably is at least 0.25 weight percent. Preferably, the amount of polyether is at most 20 weight percent, based on the weight of polyether and superabsorbent polymer, more preferably is at most 10 weight percent, even more preferably is at most 4 weight percent, and most preferably is at most 2 weight percent. The polyether preferably is thermoplastic.
The polyether employed in the composition of the present invention may be employed in any form such as, for example, neat, or formulated as part of a hot melt adhesive, or as a latex, a suspension, or a fiber, including a multicomponent fiber, or in particulate form, or as mixture of these forms.
Preferably, the HFPE comprises any one of the following hydroxy-functional polyethers:
(1) poly(hydroxy-ethers) polymers having repeating units represented by the formula:
(2) poly(hydroxy amino ethers) having repeating units represented by the formula:
(3) poly(hydroxy ether sulfonamides) having repeating units represented by the formula:
(4) poly(hydroxy ether sulfides having repeating units represented by the formula:
(5) poly(hydroxy amide ethers) having repeating units represented independently by any one of the formulas:
(6) poly(hydroxy amide ethers) having repeating units represented by any one of the formulas:
(7) poly(hydroxy ester ethers) or poly(hydroxy esters) having repeating units represented by the formula:
wherein R
5
is
R
6
is a divalent organic moiety which is predominantly hydrocarbylene or
R
7
is
each R independently is alkyl or hydrogen; R
1
and R
3
are independently a substituted or an unsubstituted alkyl or aryl moiety wherein each substituent independently is a monovalent moiety which is inert in the reactions used to prepare the hydroxy-functionalized polyethers, such as cyano, halo, amido, hydroxy and hydroxyalkyl; each A independently is a diamino moiety or a combination of different amine moieties; each Ar independently is a divalent aromatic moiety; each B, R
2
, and R
4
is independently a divalent organic moiety which is predominantly hydrocarbylene; each R
8
independently is methyl or hydrogen; m, x and y are each independently from 0 to 100; and n is an integer from 5 to 1000.
The term “predominantly hydrocarbylene” means a divalent radical which is predominantly hydrocarbon, but which optionally contains a minor amount of one or more heteroatomic moieties such as oxygen, sulfur, imino, sulfonyl, and sulfoxyl.
In the preferred embodiment of the present invention, R is hydrogen; R
1
and R
3
are independently methyl, ethyl, propyl, butyl, 2-hydroxyethyl or phenyl; Ar, B, R
2
and R
4
are independently 1,3-phenylene, 1,4-phenylene, sulfonyldiphenylene, oxydiphenylene, thiodiphenylene or isopropylidenediphenylene; and each A independently is 2-hydroxyethylimino, 2-hydroxypropylimino, piperazenyl or N,N′-bis(2-hydroxyethyl)-1,2-ethylenediimino. In one embodiment of the invention, the polyether is not the reaction product of a dicarboxylic acid with a diglycidyl ether.
The hydroxy-functional polyethers having repeating units represented by Formula I are prepared, for example, by contacting a diglycidyl ether or a combination of diglycidyl ethers with a dihydric phenol, such as a bisphenol, or a mixture of dihydric phenols using the process described in U.S. Pat. No. 5,164,472. Alternatively, the poly(hydroxy ethers) are obtained by allowing a dihydric phenol or a combination of dihydric phenols to react with an epihalohydrin by the process described by Reinking, Barnabeo, and Hale in the
Journal of Applied Polymer Science
, Volume 7, page 2135 (1963). Preferably the poly(hydroxy ether) of Formula I is a poly(hydroxy phenoxyether).
The polyetheramines having repeating units represented by Formula II are prepared by contacting one or more of the diglycidyl ethers of a dihydric phenol with a difunctional amine (an amine having two amine hydrogens) under conditions sufficient to cause the amine moieties to react with epoxy moieties to form a polymer backbone having amine linkages, ether linkages and pendant hydroxyl moieties. These polyetheramines are described in U.S. Pat. No. 5,275,853. The polyetheramines can also be prepared by contacting a diglycidyl ether or an epihalohydrin with a difunctional amine.
The hydroxy-functional poly(ether sulfonamides) having repeating units represented by Formulas IIIa and IIIb are prepared, for example, by polymerizing an N,N′-dialkyl or N,N′-diaryldisulfonamide with a diglycidyl ether as described in U.S. Pat. No. 5,149,768.
The hydroxy-functional polyethers having repeating units represented by Formula IV are prepared by reacting a diglycidyl ether and a dithiol as described in U.S. Pat Nos. 4,048,141 and 4,171,420.
The poly(hydroxy amide ethers) represented by Formula V are prepared by contacting a bis(hydroxyphenylamido)alkane or arene, or a combination of 2 or more of these compounds, such as N,N′-bis(3-hydroxyphenyl)adipamide or N,N′-bis(3-hydroxyphenyl)glutaramide, with a
Dukes Charles D.
Shaffer Donna G.
Hayhurst Paul D.
Rajguru U. K
Seidleck James J.
The Dow Chemical Company
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