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Patent US5656333 - Method of producing nonwoven articles - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsNonwoven articles having high durability and absorbent characteristics, and their methods of manufacture, are presented. One preferred article is characterized by (a) a nonwoven web comprised of organic fibers comprised of polymers having a plurality of pendant hydroxyl groups; and (b) a binder comprising...http://www.google.com/patents/US5656333?utm_source=gb-gplus-sharePatent US5656333 - Method of producing nonwoven articlesAdvanced Patent SearchPublication numberUS5656333 APublication typeGrantApplication numberUS 08/653,856Publication dateAug 12, 1997Filing dateMay 28, 1996Priority dateJun 2, 1993Fee statusLapsedAlso published asCA2163109A1, CN1044269C, CN1124985A, DE69403797D1, DE69403797T2, EP0705354A1, EP0705354B1, US5641563, US5883019, US6013587, WO1994028223A1Publication number08653856, 653856, US 5656333 A, US 5656333A, US-A-5656333, US5656333 A, US5656333AInventorsJack G. Truong, Willa M. Studiner, Bradford B. Wright, Michael M. Rock, Jr.Original AssigneeMinnesota Mining And Manufacturing CompanyExport CitationBiBTeX, EndNote, RefManPatent Citations (43), Non-Patent Citations (6), Referenced by (18), Classifications (30), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetMethod of producing nonwoven articles
US 5656333 AAbstract
Nonwoven articles having high durability and absorbent characteristics, and their methods of manufacture, are presented. One preferred article is characterized by
(b) a binder comprising an at least partially crosslinked and at least partially hydrolyzed polymeric resin having a plurality of pendant resin hydroxyl groups, the resin crosslinked by a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides, the polymeric resin derived from monomers selected from the group consisting of monomers within the general formula ##STR1## wherein: X is selected from the group consisting of Si(OR4 OR5 OR6) and O(CO)R7 ; and
R1 -R7 inclusive are independently selected from the group consisting of hydrogen and organic radicals having from 1 to about 10 carbon atoms, inclusive, and combinations thereof.
1. A method of making an absorbent nonwoven article comprised of a nonwoven web of fibers, at least a portion of the fibers having a binder coated thereon, the method comprising:(a) providing a nonwoven web of organic fibers, the fibers comprising polymers having a plurality of pendant hydroxyl groups; (b) coating the nonwoven web with a binder precursor composition comprising a silanol modified, at least partially crosslinked, and at least partially hydrolyzed polyvinyl alcohol resin and a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates, dialdehydes and amorphous metal oxides; and (c) solidifying the binder precursor composition on the nonwoven web to form the binder and provide an absorbent nonwoven article, the binder comprising a crosslinked polyvinyl alcohol wherein amorphous metal oxides coordinate with silanol groups on the polyvinyl alcohol backbone and wherein the organic titanates and dialdehydes coordinate with secondary hydroxyl groups on the polyvinyl alcohol backbone. 2. The method as defined in claim 1 wherein the providing of the nonwoven web comprises forming an open, lofty, 3-dimensional nonwoven web comprising the organic fibers; and entangling the fibers of the web to provide an entangled fiber web.
3. The method as defined in claim 1 wherein the organic fibers have a fineness within the range from about 0.5 to about 10 denier.
4. The method as defined in claim 1 wherein the organic fibers of the nonwoven web are selected from the group consisting of polyvinyl alcohol, cotton, rayon, polyester, polypropylene, polyethylene and combination of the foregoing materials.
5. The method as defined in claim 4 wherein the rayon comprises viscose rayon and cuprammonium rayon.
6. The method as defined in claim 1 wherein the organic fibers comprise a blend of rayon fibers and polyvinyl alcohol fibers wherein the weight ratio of polyvinyl alcohol fibers to rayon fibers is from about 1:100 to 100:1.
7. The method as defined in claim 1 wherein the polyvinyl alcohol resin comprises the hydrolyzed reaction product of vinyl acetate and vinyl trialkoxysilane.
8. The method as defined in claim 1 wherein the providing of the nonwoven web further comprises entangling the web.
9. The method as defined in claim 1 wherein the binder further comprises optional components selected from colorants, softeners, fragrances, fillers, bactericidal agents, or combinations of any of the foregoing materials.
10. The method as defined in claim 1 wherein the coating of the web is accomplished by roll coating, spray coating, immersion coating, gravure coating, or transfer coating.
11. The method as defined in claim 1 wherein the binder is coated on the fibers of the nonwoven web in a manner to provide a finished article comprising 10% to 60% by weight of the binder precursor after solidifying.
12. A method of making an absorbent nonwoven article comprised of a nonwoven web of fibers, at least a portion of the fibers having a binder coated thereon, the method comprising:(a) providing a nonwoven web of organic fibers, the fibers comprising polymers having a plurality of pendant hydroxyl groups; (b) coating the nonwoven web with a binder precursor composition comprising a silanol modified, at least partially crosslinked, and at least partially hydrolyzed polyvinyl alcohol resin and a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides; and (c) solidifying the binder precursor composition on the nonwoven web to form the binder and provide an absorbent nonwoven article, the binder comprising a crosslinked polyvinyl alcohol wherein amorphous metal oxides coordinate with silanol groups on the polyvinyl alcohol backbone and wherein the organic titanates coordinate with secondary hydroxyl groups on the polyvinyl alcohol backbone. 13. The method as defined in claim 12 wherein the providing of the nonwoven web comprises forming an open, lofty, 3-dimensional nonwoven web comprising the organic fibers; and entangling the fibers of the web to provide an entangled fiber web.
14. The method as defined in claim 12 wherein the organic fibers have a fineness within the range from about 0.5 to about 10 denier.
15. The method as defined in claim 12 wherein the organic fibers of the nonwoven web are selected from the group consisting of polyvinyl alcohol, cotton, rayon, polyester, polypropylene, polyethylene and combination of the foregoing materials.
16. The method as defined in claim 15 wherein the rayon comprises viscose rayon and cuprammonium rayon.
17. The method as defined in claim 12 wherein the organic fibers comprise a blend of rayon fibers and polyvinyl alcohol fibers wherein the weight ratio of polyvinyl alcohol fibers to rayon fibers is from about 1:100 to 100:1.
18. The method as defined in claim 12 wherein the polyvinyl alcohol resin comprises the hydrolyzed reaction product of vinyl acetate and vinyl trialkoxysilane.
19. The method as defined in claim 12 wherein the providing of the nonwoven web further comprises entangling the web.
20. The method as defined in claim 12 wherein the binder further comprises optional components selected from colorants, softeners, fragrances, fillers, bactericidal agents, or combinations of any of the foregoing materials.
21. The method as defined in claim 12 wherein the coating of the web is accomplished by roll coating, spray coating, immersion coating, gravure coating, or transfer coating.
22. The method as defined in claim 12 wherein the binder is coated on the fibers of the nonwoven web in a manner to provide a finished article comprising 10% to 60% by weight of the binder precursor after solidifying.
23. A method of making an absorbent nonwoven article comprised of a nonwoven web of fibers, at least a portion of the fibers having a binder coated thereon, the method comprising:(a) providing a nonwoven web of organic fibers, the fibers comprising polymers having a plurality of pendant hydroxyl groups; (b) coating the nonwoven web with a binder precursor composition comprising crosslinked and at least partially hydrolyzed resin having a plurality of pendant resin hydroxyl groups, and a crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides, the resin derived from first and second monomers, the first monomer selected from the group consisting of monomers within the general formula ##STR5## wherein: X is Si(OR4 OR5 OR6);said second monomer selected from the group consisting of monomers within the general formula ##STR6## wherein: Y is O(CO)R7 ; and R1, R2, R3, R4, R5, R6 and R7 are independently selected from the group consisting of hydrogen and organic radicals having from 1 to about 10 carbon atoms. (c) solidifying the binder precursor composition on the nonwoven web to form the binder and provide an absorbent nonwoven article, the binder comprising a crosslinked polyvinyl alcohol. 24. The method as defined in claim 23 wherein the providing of the nonwoven web comprises forming an open, lofty, 3-dimensional nonwoven web comprising the organic fibers; and entangling the fibers of the web to provide an entangled fiber web.
25. The method as defined in claim 23 wherein the organic fibers have a fineness within the range from about 0.5 to about 10 denier.
26. The method as defined in claim 23 wherein the organic fibers of the nonwoven web are selected from the group consisting of polyvinyl alcohol, cotton, rayon, polyester, polypropylene, polyethylene and combination of the foregoing materials.
27. The method as defined in claim 26 wherein the rayon comprises viscose rayon and cuprammonium rayon.
28. The method as defined in claim 23 wherein the organic fibers comprise a blend of rayon fibers and polyvinyl alcohol fibers wherein the weight ratio of polyvinyl alcohol fibers to rayon fibers is from about 1:100 to 100:1.
29. The method as defined in claim 23 wherein the providing of the nonwoven web further comprises entangling the web.
30. The method as defined in claim 23 wherein the binder further comprises optional components selected from colorants, softeners, fragrances, fillers, bactericidal agents, or combinations of any of the foregoing materials.
31. The method as defined in claim 23 wherein the coating of the web is accomplished by roll coating, spray coating, immersion coating, gravure coating, or transfer coating.
32. The method as defined in claim 23 wherein the binder is coated on the fibers of the nonwoven web in a manner to provide a finished article comprising 10% to 60% by weight of the binder precursor after solidifying.
This application is a division of U.S. patent application Ser. No. 08/536,071, filed Sep. 29, 1995, which is a continuation of U.S. patent application Ser. No. 08/070,270, filed Jun. 2, 1993, now abandoned.
In accordance with the present invention, absorbent nonwoven articles are presented which can be produced using binder crosslinking agents which are less troublesome to handle, and which afford the inventive articles with as good or better absorbency and physical properties than known articles. In addition, certain preferred embodiments of the inventive articles may be made without the use of any chemical crosslinkers.
(b) a binder comprising an at least partially crosslinked and at least partially hydrolyzed polymeric resin having a plurality of pendant resin hydroxyl groups, the resin crosslinked by a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides, the polymeric resin derived from monomers selected from the group consisting of monomers within the general formula ##STR2## wherein: X is selected from the group consisting of Si(OR4 OR5 OR6) and O(CO)R7 ; and
Preferably, the binder is bonded to at least a portion of the organic fibers through bonds between the pendant fiber hydroxyl groups, a bonding agent, and the pendant resin hydroxyl groups, wherein the crosslinking agent and bonding agent are independently selected from the group consisting of organic titanates and amorphous metal oxides. Also preferred articles in accordance with this aspect of the invention are those wherein the crosslinking agent and bonding agent are the same compounds, and wherein R4 -R7 inclusive are methyl (--CH3).
The binders useful in the articles of the invention improve on conventional formaldehyde cross-linking agents which tend to embrittle the web fibers, reducing web strength, softness, and absorption, and which present chemical hazards.
FIG. 1 is a perspective view of a wipe made in accordance with the invention;
1. Articles Employing Chemically Crosslinked PVA Binders
Nonwoven webs of fibers for use in the articles of the invention may be made using methods well documented in the nonwoven literature (see for example Turbak, A. "Nonwovens: An Advanced Tutorial", Tappi Press, Atlanta, Ga., (1989). The uncoated (i.e., before application of any binder) web should have a thickness in the range of about 10 to 100 mils (0.254 to 2.54 mm), preferably 30 to 70 mils (0.762 to 1.778 mm), more preferably 40 to 60 mils (1.02 to 1.524 mm). These preferred thicknesses may be achieved either by the carding/crosslapping operation or via fiber entanglement (e.g., hydroentanglement, needling, and the like). The basis weight of the uncoated web preferably ranges from about 50 g/m2 up to about 250 g/m2.
Silanol modified PVA's used in the present invention may be made via the copolymerization of any one of a number of ethylenically unsaturated monomers having hydrolyzable groups with an alkoxysilane-substituted ethylenically unsaturated monomer. Examples of the former are vinyl acetate, acetoxyethyl acrylate, acetoxyethylmethacrylate, and various propyl acrylate and methacrylate esters. Examples of alkoxysilane-substituted ethylenically unsaturated monomers include vinyl trialkoxysilanes such as vinyl trimethoxysilane and the like.
The theoretical crosslink density may range from 1 to about 40 mole % based on mole of ethyleneically unsaturated monomer. This may be achieved by addition of one or more aqueous titanates and, optionally, dialdehyde/NH4 Cl solutions to a polyvinyl alcohol binder resin. Though dialdehydes such as glyoxal and several classes of titanium complexes have been shown to crosslink aqueous compositions of polyvinyl alcohol, we have found that chelating titanates such as dihydroxybis(ammonium lactato) titanium (available under the trade designation "Tyzor LA" from du Pont) and titanium orthoesters such as Tyzor 131 provide excellent crosslinking for wiping articles described in this invention. It is desired that crosslinking be avoided until curing conditions (i.e., high temperatures) are present. Thus, organic acids, such as citric acid, may help to stabilize titanates such as dihydroxybis (ammonium lactato) titanium in aqueous compositions until the binder precursors are exposed to crosslinking and curing conditions.
To improve the tensile and tear strength of the inventive articles, and to reduce lint on the surface of the articles, it may be desirable to entangle (such as by needletacking, hydroentanglement, and the like) the uncoated web, or calender the uncoated and/or coated and cured nonwoven articles of the invention. Hydroentanglement may be employed in cases where fibers are water insoluble. Calendering of the binder coated web at temperatures from about 5� to about 40� C. below the melting point of the fiber may reduce the likelihood of lint attaching to the surface of the inventive articles and provide a smooth surface. Embossing of a textured pattern onto the wipe may be performed simultaneously with calendering, or in a subsequent step.
The absorbent nonwoven articles in accordance with this aspect of the invention comprise a nonwoven web of a plurality of organic fibers comprising polymers having a plurality of pendant hydroxyl groups, a major portion of the polymers being at least partially hydrolyzed polymerized monomers selected from the group consisting of monomers within the general formula ##STR4## wherein X is O(CO)R7 the provisos mentioned above. A binder coats at least a portion of the fibers, the binder consisting essentially of polyvinyl alcohol insolubilized with an effective amount of polyacrylic acid. Optionally, chemical crosslinking agents and/or bonding agents may also be employed.
Triad syndiotacticity, as used herein, means that of a triad of three pendant hydroxyl groups, all three are on the same side of the polymer chain. This is opposed to atactic, which means that the hydroxyl groups are randomly arranged, and isotactic, meaning the hydroxyl groups are positioned in alternating pattern from side-to-side on the polymer chain.
Optionally, small amounts (i.e., less than about 5 wt. %) of additional monomers may be incorporated in the parent polymer to improve various properties of the polyvinyl alcohol derived therefrom. A particularly preferred syndiotactic PVA (and used in Examples 65-91 below) is poly(vinyl trifluoroacetate-co-[3-allyl-2,2'-dihydroxy-4,4'-dimethoxybenzophenone]) (99.95:0.05 by weight, abbreviated as PVTFA). The triad syndiotacticity measured by 1 H NMR was 51%, isotacticity =7%, atacticity =42%.
The syndiotacticity of the polyvinyl alcohol binder employed in this aspect of the invention typically and preferably ranges from about 45% to 100% syndiotacticity. It is known that increasing syndiotacticity at constant degree of polymerization results in increased melting point for the gel. (See Matsuzawa, S. et al., "Colloid Poly. Sci. 1981", 259 (12), pp. 1147-1150.) For this reason higher syndiotacticity is preferred since mechanical strength and thermal stability are improved, but aqueous compositions of polyvinyl alcohol become more viscous and/or thixotropic as syndiotacticity increases due to gel formation. For these reasons, and owing to methods of preparation, the preferred range of syndiotacticity when coated from aqueous compositions preferably ranges from about 25 to about 65% syndiotacticity. Although detrimental to the flexibility of the nonwoven articles of the invention, it may be advantageous to incorporate a small amount (e.g., up to about 10 mole %) of a chemical crosslinker such as those mentioned above in order to eliminate washout of the binder during use. Preferred crosslinkers are the above-mentioned titanates, with dialdehydes and the like being suitable but less preferred for ecological reasons.
Web 48 may then be passed through another set of calender rollers 50, which may used to emboss a pattern, fuse the surfaces, and impart other qualities to the article. Web 52 generally has a thickness of no more than 60 mils (1.524 mm), and a weight ranging from about 50 g/m2 to about 250 g/m2.
Tensile strength measurements were made on 1�3 inch (2.54�7.62 cm) wringer damp, die cut samples using an Instron Model "TM", essentially in accordance with ASTM test method D-5035. A constant rate of extension (CRE) was employed, and jaws were clamp-type. Rate of jaw separation was 9.3 inches/min. (23.6 cm/min).
Elmendorf tear tests were conducted on 2.5�11 inch (6.35�27.94 cm) damp, die-cut, notched (20 mm) samples, essentially in accordance with ASTM D-1424, using an Elmendorf Tear Tester model number 60-32, from Thwing-Albert Co., with a 3200 gram pendulum. An average of four measurement was used. A high value is desired.
Absorption measurements were made on 6�8 inch (15.24�20.32 cm) samples which were die-cut in damp conditions. The absorption measurements are reported using the following terms:
(f) % Weight (H2 O) Loss=(No Drip Weight--With Drip Weight)/No Drip Weight.
(g) Grams Water Absorbed per Square foot (grams/929 cm2)=3�(No Drip Weight-Dry Weight).
(i) MD=machine direction, CD=cross direction, "abs" =absorbed, and "eff"=effective
(j) effective water absorption=3�(no drip weight-damp weight).
The materials are used in the examples which follow:
"R1130" is the trade designation for a copolymer of vinyl silane and vinyl acetate containing from about 0.5 to about 1.0 molar % of the silyl groups as vinylsilane units, a degree of polymerization of about 1700, and degree of hydrolysis of the vinyl acetate units preferably of 99+ % (Kuraray Chemical KK, Japan).
"Airvol 165" is the trade designation for a 99.5+ % hydrolyzed polyvinyl alcohol from Air Products and Chemicals, Inc.
General Procedure I for Preparing Inventive Articles
Nonwoven webs consisting of a blend of polyvinyl alcohol and rayon fibers (45% polyvinyl alcohol fiber having 1.5 denier and a length of 1.5 inch (3.81 cm) purchased from Kuraray, Japan, and 55% rayon fiber having 1.5 denier and a length of 1 and 9/16 inch (3.97 cm) purchased from BASF) were made using a web, making machine known under the trade designation "Rando-Webber". The resultant web had a nominal basis weight of 11.5 g/ft2 (123.8 g/m2) and an average thickness of 0.052 inch (0.132 cm).
Silanol modified polyvinyl alcohol granules ("R1130") were added to deionized water in proportions up to 10 wt. % solid in a stirred flask. The flask was then heated to 95� C. until reflux condition is achieved. The polymeric solution was then kept at reflux for a minimum of 45 minutes with adequate mixing. The solution was then cooled down to room temperature (about 25� C.). The silanol modified PVA solution was then diluted to 2.5 wt. % solid. Reactants such as Nalco 8676, Tyzor LA, Tyzor 131, and glyoxal were then added to the silanol modified PVA solution at various proportions and combinations as described in the examples to follow.
A 12�15 inch (30.48�38.1 cm) piece of this nonwoven web was placed in a pan and saturated with approximately 200 g of an aqueous coating solution containing 5.00 g of total polymer.
Saturated samples were then dried and cured in a flow-through oven at various conditions to be described in the examples below. When curing was completed, the samples were conditioned for 60 minutes in 60�-80� F. (140�-176� C.) tap water then dried. Samples were then analyzed for hydrophilicity, water retention and absorption, tensile strength, tear strength, and dry wiping properties.
Examples 1-10 and Comparative Example A
The results of testing on Comparative Example A, a nonwoven wipe originally 59 mils (0.149 cm) thick, and known under the trade designation "Brittex-11" (available from Vileda, a division of Freudenberg Co., Germany, and which is a PVA web coated with a PVA binder crosslinked with formaldehyde) were as follows:
Total Water Absorption=137.5 g/ft2 (1479 g/m2);
tensile strength (machine direction)=273 lbs/in2 (1882 KPa);
tensile strength (cross direction)=203 lbs/in2 (1399 KPa);
Elmendorf Tear strength (machine direction and damp)=86.
The test results for the inventive nonwovens of Examples 1-10 are presented in Tables 1 and 2. The nonwovens of Examples 1-10 were prepared as described in General Procedure I. For each example, 200 g of the polymeric solution (2.5 wt. % of R1130) was added with the reactants described below along with 0.1 g of Orcabrite Green BN 4009 pigment. The wt. % designated below represents the wt. % of active reactant (solid) over the R1130 polymer. The coated samples were dried at 150� F. (65.5� C.) for 2 hrs. then 250� F. (121.1� C.) for 2 hrs. and finally cured at 300� F. (148.8� C.) for 10 minutes. All samples had excellent dry wiping properties, low drag, and good feel.
TABLE 1______________________________________                      g H2O Sample      Wet out  abs/g of                             g H2O  % H2OEx. # Description (sec)    Dry wipe                             abs/(ft2)                                    Loss______________________________________1     Uncoated    0        11.37  148.7  24.78 nonwoven substrate COMPARATIVE2     R1130       0        8.90   158.6  18.553     R1130/0.5   0        8.37   159.7  17.2 wt. % Nalco 8676/5 wt. % Tyzor 1314     R1130/0.5 wt.             0        7.46   145.7  21.2 % Nalco 8676/ 15 wt. % Tyzor 1315     R1130/0.5 wt.             0        8.42   150.3  15.95 % Nalco 8676/5 wt. % Tyzor LA6     R1130/0.5 wt.             0        7.79   155.9  16.73 % Nalco 8676/15 wt. % Tyzor LA7     R1130/5 wt. %             0        8.26   145.5  15.71 Tyzor 1318     R1130/15 wt. %             0        7.83   150.4  17.11 Tyzor 1319     R1130/5 wt. %             0        8.52   151.1  16.47 Tyzor LA10    R1130/15 wt. %             0        8.06   136.6  12.93 Tyzor LA______________________________________
TABLE 2______________________________________          Tensile Strength          (KPa)     Elmendorf TearEx. # Sample Description                MD      CD    MD    CD______________________________________1     Uncoated nonwoven                1289     641  74.7  56.3 substrate COMPARATIVE2     R1120          2126    2011  85.5  93.03     R1130/0.5 wt. %                2555    2012  95.0  88.0 Nalco 8676/5 wt. % Tyzor 1314     R1130/0.5 wt. % Nalco 8696/15 wt. %                2770    2032  86.3  100 Tyzor 1315     R1130/0.5 wt. %                2543    2001  76.7  85.0 Nalco 8676/5 wt. % Tyzor LA6     R1130/0.5 wt. %                2802    1921  90.3  100 Nalco 8676/15 wt. % Tyzor LA7     R1130/5 wt. %  2481    2155  77.0  84.5 Tyzor 1318     R1130/15 wt. % 2327    2201  90.8  84.0 Tyzor 1319     R1130/5 wt. %  2356    1787  80.3  82.5 Tyzor LA10    R1130/5 wt. %  2769    2090  78.0  87.5 Tyzor LA______________________________________
The wipes of Example 11-20 were prepared as described in General Procedure I, and dried and cured as in Examples 1-10, except that the final 10 minute cure at 300� F. (121.1� C.) was eliminated. The absorbency, tensile strength and tear test results are presented in Tables 3 and 4.
It can be seen comparing the data of Tables 3 and 4 with the data of Tables 1 and 2 that addition of Tyzor LA or Tyzor 131, and the final 121.1� C. cure, gave immediate wet-out and consistently higher tensile strength and Elmendorf tear values.
TABLE 3______________________________________                       g H2OSample         Wet out abs/g of                              g H2O % H2OEx. #Description    (sec)   dry wipe                              abs/(ft2)                                    Loss______________________________________11   R1130/0.5 wt. %               28      8.87   152.8 17.7Nalco 867612   R1130/1 wt. %  60+     7.80   141.5 14.09Nalco 867613   R1130/1.5 wt. %               60+     7.65   141.7 13.99Nalco 867614   R1130/2.0 wt. %               60+     7.48   138.7 14.92Nalco 867615   R1130/0.5 wt. %               0       8.35   160.7 19.60Nalco 8676/1wt. % Tyzor LA16   R1130/0.5 wt. %               0       8.49   161.5 19.70Nalco 8676/5wt. % Tyzor LA17   R1130/0.5 wt. %               0       8.31   155.6 16.57Nalco 8676/10wt. % Tyzor LA18   R1130/0.5 wt. %               0       8.49   164.2 18.63Nalco 8676/1wt. % Tyzor 13119   R1130/0.5 wt. %               0       8.12   165.0 19.69Nalco 8676/5wt. % Tyzor 13120   R1130/0.5 wt. %               0       8.61   164.8 21.33Nalco 8696/10wt. % Tyzor 131______________________________________
TABLE 4______________________________________Sample        Tensile strength (Kpa)                           Elmendorf TearEx. #   Description             MD      CD     MD     CD______________________________________11      R1130/0.5 2218    2022   91.7   85.0   wt. %   Nalco 867612      R1130/1   2212    1856   88.8   100.0   wt. %   Nalco 867613      R1130/1.5 2678    1948   83.3   90.0   wt. %   Nalco 867614      R1130/2.0 2961    2164   86.3   100.0   wt. %   Nalco 867615      R1130/0.5 2425    1783   78.3   100.0   wt. % Nalco   8676/1 wt. %   Tyzor LA16      R1130/0.5 2182    2086   74.5   100.0   wt. %   Nalco 8676/   5 wt. %   Tyzor LA17      R1130/0.5 2379    2130   100.0  95.0   wt. %   Nalco 8676/   10 wt. %   Tyzor LA18      R1130/0.5 2390    1959   90.3   92.0   wt. %   Nalco 8676/   1 wt. %   Tyzor 13119      R1130/0.5 2295    1904   85.0   100.0   wt. %   Nalco 8676/   5 wt. %   Tyzor 13120      R1130/0.5 2419    1837   78.0   100.0   wt. %   Nalco 8676/   10 wt. %   Tyzor 131______________________________________
The inventive nonwovens of Examples 21-27 were prepared as described in General Procedure I. For each sample, 200 g of the polymeric solution (2.5 wt. % of R1130 ) was mixed with 1.54 g of glyoxal (40 wt. % aqueous solution) and 0.25 g of NH4 Cl and then reacted with the reactants described below. The wt. % designated below represents the wt. % of active reactant (solid) over the R1130 polymer. The coated samples were dried at 110� F. (92.2� C.) for 4 hrs. All samples had excellent dry wiping properties, low drag, and good feel. The results of the absorbency, tensile strength, and tear strength are presented in Tables 5 and 6.
TABLE 5______________________________________                      g H2O Sample      Wet out  abs/g of                             g H2O  % H2OEx. # Description (sec)    Dry wipe                             abs/(ft2)                                    Loss______________________________________21    NONE:        0       7.40   127.9  15.27 COMPARATIVE22    1 wt. %      60+     8.86   157.1  24.28 Nalco 867623    3 wt. %      60+     9.39   162.9  26.12 Nalco 867624    5 wt. %      60+     8.03   139.3  23.10 Nalco 867625    1 wt. %      31      8.25   148.7  19.70 Al2(SO4)3 (100% solid)26    3 wt. %      16      8.53   153.8  21.82 Al2(SO4)3(100 % solid)27    5 wt. %      60+     8.54   147.1  21.32 Al2(SO4)3(100 % solid)______________________________________
TABLE 6______________________________________         Tensile Strength         (KPa)      Elmendorf TearEx. # Sample Description               MD       CD    MD    CD______________________________________21    NONE:         1717     2616  100.0 86.3 COMPARATIVE22    1 wt. %       1693     2639   94.0 94.3 Nalco 867623    3 wt. %       2509     1915  --    91.0 Nalco 867624    5 wt. %       2248     3230  100.0 90.3 Nalco 867625    1 wt. %       1880     2202  100.0 82.7 Al2(SO4)3(100 % solid)26    3 wt. %       1813     2273  100.0 85.0 Al2(SO4)3 (100% solid)27    5 wt. %       2449     2030  100.0 96.0 Al2(SO4)3 (100% solid)______________________________________
Examples 28-29 demonstrated the use of nonwoven web containing 100% PVA fibers. The nonwoven web was made from 100% PVA fibers which were 1.5 denier and 1.5 inch long (3.81 cm), purchased from Kuraray, Japan, with a basis weight of 7.0 g/ft2 (75.3 g/m2) using a carding machine known under the trade designation "Rando-Webber." A 12�15 inch (30.48�38.1 cm) sample of this web was coated with a solution containing: 130 g of R1130 solution (2.5 wt. % solid), 0.16 g of Nalco 8676 (10% solid), 1.63 g of Tyzor 131 (20 wt. % in water), and 0.16 g of Orcobrite Royal blue pigment #R2008. The coated sample was dried at 150� F. (65.5� C.) for 2 hrs. then cured at 300� F. (148.9� C.) for an additional 15 minutes. The coated sample had a rubbery feel. The absorbency and tensile strength data are presented in Tables 7 and 8.
TABLE 7______________________________________                      g H2O Sample      Wet out  abs/g of                             g H2O  % H2OEx. # Description (sec)    dry wipe                             abs/(ft2)                                    Loss______________________________________28    Uncoated    0        12.74  159.3  30.71 100% PVA fiber web COMPARATIVE29    Coated 100% 7        4.74   81.3   13.32 PVA fiber web______________________________________
TABLE 8______________________________________               Tensile Strength (KPa)Ex. #   Sample Description                     MD       CD______________________________________28      Uncoated 100% PVA fiber                     1751     2042   web COMPARATIVE29      Coated 100% PVA fiber web                     2752     2352______________________________________
Examples 30-31 demonstrated the use of a nonwoven web containing a blend of PVA and cotton fibers. The nonwoven web was made from 50 wt. % PVA fibers which were 1.5 denier and 1.5 inch (3.81 cm) in length, purchased from Kuraray, Japan, and 50 wt. % cotton fibers with a resultant basis weight of 5.5 g/ft2 (59.2 g/m2) using a web making machine known under the trade designation "Rando-Webber." A 12�15 inch (30.48�38.1 cm) sample of this web was coated with a solution containing: 110 g of R1130 solution (2.5 wt. % solid in H2 O), 0.13 g of Nalco 8676 (10% solid in H2 O), 1.38 g of Tyzor 131 (20% solid in H2 O), and 0.14 g of Orcobrite Royal blue pigment #R2008. The coated sample was dried at 150� F. (65.5� C.) for 2 hours, then cured at 300� F. (148.9� C.) for an additional 15 minutes. The coated sample had excellent dry wiping properties, low drag, and good feel. The absorbency and tensile strength data are presented in Tables 9 and 10.
TABLE 9______________________________________                       g H2OSample         Wet out abs/g of                              g H2O % H2OEx. #Description    (sec)   Dry wipe                              abs/(ft)                                    Loss______________________________________30   Uncoated 50/50 0       22.27  170.4 50.16blend ofPVA/Cotton fibersweb: COMPARATIVE31   Coated 50/50   4       5.82   57.7  17.41blend ofPVA/Cotton fibersweb______________________________________
TABLE 10______________________________________              Tensile Strength (KPa)Ex. #   Sample Description                    MD       CD______________________________________30      Uncoated 50/50 blend of                    384      411   of PVA/Cotton fibers   web: COMPARATIVE31      Coated 50/50 blend of                    3689     2919   PVA/Cotton fibers web______________________________________
The nonwoven web used in Example 32 was made from rayon fibers which were 3.0 denier and 2.5 inches (6.35 cm) long from Courtaids Chemical Company, England, using a carding/crosslap/needletacking process. Its basis weight was 16.2 g/ft2 (174.3 g/m2). A 15�15 inch sample of this web (38.1�38.1 cm) was coated with a solution containing: 250 g of R1130 solution (2.5% solid in H2 O), 0.31 g of Nalco 8676 (10% solid in H2 O), 3.13 g of Tyzor 131 (20 wt. % in H2 O), and 0.4 g of Orcobrite Royal blue pigment #R2008. The coated sample was dried at 150� F. (65.5� C.) for 2 hours and then at 250� F. (121.1� C.) for 2 hours, and finally at 300� F. (148.8� C.) for an additional 10 minutes. The coated sample had excellent dry wiping properties, low drag, and soft feel.
Example 33 demonstrated the preparation of a bactericidal wipe based on iodine and the polyvinyl alcohol/polyiodide complex. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g of water was prepared. This solution was then saturated on a wipe prepared using the procedure of Example 5. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue color which is a characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water, iodine color and odor were plainly evident.
Nonwoven webs consisting a blend of polyvinyl alcohol and rayon fibers (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 inch (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 1 and 9/16 inch (3.97 cm) purchased from BASF) were made using a web making machine known under the trade designation Rando-Webber. The resultant web had an average dry weight of 12 g/ft2 (129 g/m2) and nominal thickness of 0.056 inch (0.142 cm).
An aqueous binder precursor solution was prepared for each example containing various amounts of Airvol 165 (a 99.8% hydrolyzed polyvinyl alcohol with molecular weight 110,000 and degree of polymerization 2500, obtained from Air Products) reacted with Tyzor LA and/or Tyzor 131 and optionally, glyoxal as described in Examples 34-47 and NH4 Cl, an acid catalyst. The binder precursor solutions also may have contained optional crosslinker(s) and pH modifiers as detailed in the Examples. A 12�15 inch (30.48�38.1 cm) piece of this nonwoven web was placed in a pan and saturated with approximately 200 g of an aqueous coating solution containing 5.00 g of total polymer.
Saturated samples were dried in a flow-through oven at 150� F. (65.5� C.), for between 30 minutes and 4 hours, and cured in a flow-through oven, preferably for greater than 10 minutes, at temperatures greater than 220� F. (104� C.). The samples were flipped every 10-30 minutes to aid in even drying conditions. When curing was completed, the samples were conditioned for 60 minutes in 60�-80� F. (15.6�-26.7� C.) tap water then dried. Samples were then analyzed for hydrophilicity, water retention and absorption, tensile strength, tear strength, and dry wiping properties.
Examples 34-38 illustrated the advantages of employing a titanate crosslinked PVA binder in wiping articles according to the invention. The wipes of Examples 34-38 were prepared as described in General Procedure II with the compositions described below at an initial coating weight of 5 g of polymeric material per 200 g solution and dried slowly at 150� F. (65.5� C.), followed by curing at 300� F. (148.9� C.). The absorbency, tensile strength, and tear data are presented in Tables 11 and 12, respectively.
TABLE 11______________________________________          Wet                 H2 O                                      Eff gEx.            Out     % H2 O                        g H2 O                              Abs/Dry H2 O/#    Description          (sec.)  Loss  abs./ft2                              wgt. (g/g)                                      ft2______________________________________34   Airvol 165          0       20.49 157.62                              6.20    116.22withoutTitanate35   Airvol 165          0       17.52 149.55                              7.95    109.86with 5%Tyzor LA36   Airvol 16-5          0       13.10 142.83                              7.51    101.49with 15%Tyzor LA37   Airvol 165          0       18.89 144.96                              7.77    106.56with 5%Tyzor 13138   Airvol 165          0       15.79 133.47                              7.21     96.06with 15%Tyzor 131______________________________________
TABLE 12______________________________________      Av. Tensile Stress                  Elmendorf Tear      (KPa)       (Damp)Ex. # Description            Machine  Cross  Machine                                   Cross______________________________________34    Airvol 165 2489     1999   100+   88 without Titanate35    Airvol 165 2916     2330   100+   69 with 5% Tyzor LA36    Airvol 165 2985     2489   83     96 with 15% Tyzor LA37    Airvol 165 2930     2296   86     93 with 5% Tyzor 13138    Airvol 165 3103     2530   75     88 with 15% Tyzor 131______________________________________
Examples 39-45 illustrated the advantages of employing a titanate, and optionally, glyoxal crosslinked PVA binder in wiping articles according to the invention. The wipes of Examples 39-45 were prepared at an initial coating weight of 5 g total PVA, 1.59 g glyoxal, and 0.25 g NH4 Cl per 200 g solution and dried slowly at 150� F. (65.5�). The absorbency, tensile strength, and tear data are presented in Tables 13 and 14, respectively.
TABLE 13______________________________________          Wet           g H2 O                              H2 O                                      Eff gEx.  Sample    Out     % H2 O                        Abs./ Abs/Dry H2 O/#    Description          (sec.)  Loss  ft2                              wgt. (g/g)                                      ft2______________________________________39   Airvol 165          1       14.47 125.37                              7.42    88.11withGlyoxal,NH4Cl,w/outTitanate40   Airvol 165          1       14.91 124.62                              7.39    87.81withGlyoxal,NH4Cl,and1% TyzorLA41   Airvol 165          1       14.65 128.88                              7.34    92.64withGlyoxal,NH4Cl,and5% TyzorLA42   Airvol 165          1       14.75 130.53                              7.35    93.33withGlyoxal,KH4Cl,and10% TyzorLA43   Airvol 165          1 to 25 13.83 121.05                              7.34    84.36withGlyoxal,NH4Cl,and1% Tyzor13144   Airvol 165          1 to 20 15.27 128.61                              7.48    91.23withGlyoxal,NR4Cl,and5% Tyzor13145   Airvol 165          1       14.58 121.92                              7.27    83.97withGlyoxal,NH4Cl,and10% Tyzor131______________________________________
TABLE 14__________________________________________________________________________              Avg. Tensile                        Elmendorf Tear        PVA   Stress (KPa)                        (Damp)Ex. #Description        Retention              Machine                   Cross                        Machine                             Cross__________________________________________________________________________39   Airvol 165        80.5  2482 2255 98   100+withGlyoxal,NH4Cl, w/outTitanate40   Airvol 165        63    2709 2193 86   100withGlyoxal,NH4Cl, and1% Tyzor LA41   Airvol 165        91.2  2592 2055 86   96withGlyoxal,NH4Cl, and5% Tyzor LA42   Airvol 165        91.9  2758 2034 88   95withGlyoxal,NH4Cl, and10% Tyzor LA43   Airvol 165        78.2  2696 2455 97   100+with GlyoxalNH4Cl, and1% Tyzor 13144   Airvol 165        86.1  2772 2392 94   100+withGlyoxal,NH4Cl, and5% Tyzor 13145   Airvol 165        75.1  2558 2310 100+ 100+withGlyoxal,NH4Cl, and10% Tyzor131__________________________________________________________________________
Example 46 demonstrated the ability to color the wiping articles of this invention made in accordance with General Procedure II in varying colors and shades. A binder binder precursor solution was prepared consisting of 100 g 5 wt. % Airvol 165, 1.68 g Tyzor LA, 0.03 g, 0.06 g, 0.13 g, 0.25 g, or 0.5 g pigment dispersion, and deionized water to achieve a total solution weight of 200 g for each run. The binder precursor solution was coated onto a 12�15 inch (30.48 cm�38.1 cm) piece of PVA/rayon nonwoven produced as described in General Procedure II, dried at 120� F. (48.9� C.) for 2 hours, and finally cured for one hour at 140� F. (57.0� C.). Upon completion of run, the samples were conditioned for 60 minutes in 60�-80� F. (140�-176� C.) water and dried. Results are shown below.
______________________________________Pigment, Amount          Results______________________________________"Orcobrite Red BN",          Good color and fastness.0.03 to 0.5 g"Orcobrite Yellow          Good color and fastness.2GN", 0.03 to 0.5 g"Orcobrite Green BN",          Good color and fastness0.03 to 0.5 g"Aqualor Green"          Good color, binder washout."Aqualor Blue" Good color, binder washout.______________________________________
The aqueous pigment dispersions known under the trade designation "Aqualor" were obtained from Penn Color (Doylestown, Pa.), while those known under the trade designation Orcobrite aqueous pigment dispersions were obtained from Organic Dyestuffs (Concord, N.C.). Good results were obtained with a wide variety of the "Orcobrite" series of pigments. A major difference between the "Aqualor" and "Orcobrite" pigment dispersions, as supplied, was the substantially higher alkalinity of "Aqualor" pigment dispersions, perhaps leading to insufficient cure by the titanate crosslinking agent. Generally speaking it was found that the best results with regard to coloring were obtained at cure temperatures of 240�-250� F. (115.6�-121� C.), although higher temperatures were also useful.
Example 47 demonstrated the ability to impregnate the synthetic wipes of the invention made in accordance with General Procedure II with a number of antibacterial, antifungal, and disinfecting solutions for use in the health care, business, and/or food service trades. A nonwoven produced in accordance with General Procedure II was saturated with an aqueous solution containing 1.2 g potassium iodide, 0.64 g solid iodine crystals, and 50 g deionized water.
A 12 by 15 inch (30.48�38.1 cm) piece of polyvinyl alcohol/rayon (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 inch (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 19/16 inch purchased from BASF) blended nonwoven fiber substrate (thickness=56 mil (0.142 cm), basis weight =11.5 g/ft2 (123.8 g/m2), prepared using a web marking of Rando-Webber) was placed in a pan and saturated with 200 g of an aqueous binder precursor solution containing 5.00 g total polyvinyl alcohol and polyacrylic acid, prepared by mixing a 5% aqueous solution of "Airvol 165" with a 2.5% aqueous solution of the polyacrylic acid. "Airvol 165" (a 99.8% hydrolyzed polyvinyl alcohol, MW=110,000, DP=2500 obtained from Air Products) was used in combination with polyacrylic acid (750,000 MW, Aldrich Chemical Co.). The binder precursor solution pH was adjusted with 85% phosphoric acid. The sample and tray were placed in a flow through drying oven at 120�-150� F. (48.9�-65.5� C.) for 2 hours followed by curing at 300� F. (148.9� C.) as specified in Table 15. The samples were flipped over after about 30 minutes and 60 minutes to aid in maintaining even drying. When curing was completed the samples were conditioned for 60 minutes in 60�-80� F. water then dried.
Example wipes 48-62 were made in accordance with General Procedure III at the conditions specified in Table 15, and subsequently analyzed for wet out, absorptivity, tensile strength, tear strength, and dry wiping properties. The test results are presented in Tables 16-17. Examples 48-62 each contained 0.1 g "Orcobrite Yellow 2GN 9000" (a yellow pigment, available from Organic Dyestuffs, Corp.).
TABLE 15__________________________________________________________________________                   % Coating                          Conditioned                   Loss During                          Coat Wt.Ex. #    Description         Cure Conditions                   Conditioning                          (g/m2)__________________________________________________________________________48  Polyacrylic         2 HR 120� F.                   4      40.5    Acid, pH = 3.0,         (48.9� C.)/    COMPARATIVE         5 MIN 300� F.         (148.9� C.)49  Airvol 165         2 HR 20� F.                   1      48.4    (polyvinyl         (48.9� C.)/    alcohol), 5 MIN 300� F.    pH = 3.0, (148.9� C.)    COMPARATIVE50  1 part    2 HR 120� F.                   0      49.5    Polyacrylic         (48.9� C.)    acid/     5 MIN 300� F.    2 parts Airvol         (148.9� C.)    165, pH = 3.051  1 part    2 HR 120� F.                   0      48.2    Polyacrylic         (48.9� C.)/    acid/     5 MIN 300� F.    3 parts Airvol         (148.9� C.)    165, pH = 3.052  1 part    2 HR 120� F.                   0      56.9    Polyacrylic         (48.9� C.)/    acid/     5 MIN 300� F.    5 Parts Airvol         (148.9� C.)    165, pH = 3.053  1 part    2 HR 120� F.                   0      58.5    Polyacrylic         (48.9� F.)/    acid/     5 MIN 300� F.    10 parts Airvol         (148.9� C.)    165, pH = 3.054  1 part    2 HR 150� F.                   0      52.4    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.555  1 part    2 HR 50� F.                   0      51.6    Polyacrylic         (65.6� C.)/    acid/     15 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.556  1 part    2 HR 150� F.                   0      55.4    Polyacrylic         (65.6� C.)/    acid/     25 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.557  0.1 part  2 HR 150� F.                   1      49.5    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.558  0.5 part  2 HR 50� F.                   1      53.5    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.559  1 part    2 HR 150� F.                   0      55.4    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 3.560  1 part    2 HR 150� F.                   0      49.7    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 4.061  1 part    2 HR 150� F.                   0      52.3    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 parts Airvol         (148.9� C.)    165, pH = 4.662  1 part    2 HR 150� F.                   1      48.3    Polyacrylic         (65.6� C.)/    acid/     5 MIN 300� F.    99 Parts Airvol         (148.9� C.)    165, pH = 3.3__________________________________________________________________________
TABLE 16______________________________________Tensile  TensileStrength Strength  Elmendorf                           ElmendorfMachine  Cross Web Tear Test                           Tear TestEx.  Direction         Direction (Machine                           (Cross Web                                    % H2 O#    (KPa)    (KPa)     Direction)                           Direction)                                    Loss______________________________________48   1910     1014      65       73      1149   3054     2240      53       90      1150   2937     2420      54      100+     1051   3296     2117      74       86      1152   2379     1751      87      100+     1153   2779     1813      81       82      1354   2772     2737      96      100+     1855   2958     2565      77      100+     2056   2854     2399      79       90      2157   2758     2365      91      100+     1658   2523     2324      88      100+     1859   2723     2461      85      100+     2060   2737     2392      89      100+     2261   2785     2358      87      100+     2262   2909     2275      90      100+     19______________________________________
TABLE 17______________________________________ Total H2 O Abs.              H2 O Abs./Dry                           Eff. H2 O Abs.Ex. # (g/ft2) Wt. (g/g)    (g/ft2)______________________________________48    175.7        9.70         105.249    137.7        7.70          98.950    142.7        7.63         101.151    139.4        7.27          94.552    126.2        6.13          84.953    136.3        6.67          96.354    158.7        7.78         114.055    157.0        8.03         111.456    156.0        7.46         111.157    148.6        7.41         105.058    159.7        7.86         115.359    160.9        8.31         116.760    158.7        8.55         116.161    162.1        8.21         118.362    150.8        7.76         108.7______________________________________
This example demonstrated the preparation of a bactericidal wipe based on iodine and a polyvinyl alcohol/polyiodide complex, and made in accordance with General Procedure III. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g water was prepared. This solution was coated onto a sample of 1:2 polyacrylic acid/polyvinyl alcohol wipe prepared as in General Procedure III above. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water iodine color and odor were plainly evident.
A 12 by 15 inch (30.48�38.1 cm) piece of polyvinyl alcohol/rayon (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 in (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 1.56 inch (3.96 cm) purchased from BASF) blended nonwoven fiber substrate (thickness=56 mil (0.142 cm), basis weight 11.5 g/ft2 (123.8 g/cm2), prepared using a web making machine known under the trade designation "Rando-Webber") was placed in a pan and saturated with 200 g of an aqueous binder precursor solution containing 5.00 g total polyvinyl alcohol. "Airvol 165" (a 99.8% hydrolyzed polyvinyl alcohol, MW=110,000, DP=2500 obtained from Air Products) was used in combination with syndiotactic polyvinyl alcohol prepared in Example 64 to comprise the polyvinyl alcohol content in Examples 65-91. The binder precursor solutions may also have contained optional crosslinker(s), and pH modifiers depending on the Example. The sample and tray were placed in a flow through drying oven at 120�-50� F. (48.9�-65.6� C.) for 3 to 4 hours as specified. The samples were flipped over after about 30 minutes and 60 minutes to aid in maintaining even drying. When curing was completed the samples were conditioned for 60 minutes in 60�-80� F. (15.6�-26.7� C.) water then dried. Samples were then analyzed for wet out, absorptivity, tensile strength, tear strength, and dry wiping properties, with the results reported in Tables 18-27.
Preparation of Syndiotactic PVA
The polyvinyl trifluoroacetate (PVTFA) copolymer described above (300 g) was dissolved in 700 g acetone. This solution was slowly added to 1700 g of 10% methanolic ammonia that had been cooled in ice to 15� C. Despite vigorous mechanical stirring a large ball of solid material formed on the stirrer blade making stirring ineffective. After addition was complete the ball of material was broken up by hand and the mixture was shaken vigorously. The process was repeated twice more (elapsed time was about 3 hr). The divided mass was vigorously mechanically stirred for 20 minutes and allowed to stand at room temperature overnight.
The supernatant liquid was decanted off leaving a mixture of white powder and yellow fibrils. The solids were collected by filtration and spread in a tray at 15.6� C. to evaporate residual solvent. The solids were collected when constant weight over 2 hr was achieved. The solid was chopped in a blender to give 87.3 g of beige powder, 92% yield, referred to hereinafter as "Syn". Analysis of this material was carried out using IR and 1 H NMR spectroscopy, and Gel Permeation Chromatography. The results indicated the likely presence of traces of trifluoroacetate esters and salts. The triad syndiotacticity measured by 1 H NMR in DMSO-d6 was 33%, atacticity=50%, isotacticity=17%, The difference between the hydrolyzed polymer and the trifluoroacetate precursor polymer may be due to acid catalyzed epimerization of hydroxyl groups during drying or solution in boiling water.
Examples 65-70 illustrated the advantages of employing syndiotactic polyvinyl alcohol alone or in blends with atactic polyvinyl alcohol in wiping articles according to the invention. The articles were prepared at an initial coating weight of 5 g total PVA/200 g solution. Curing conditions were 4 hr at 48.9� C.
TABLE 18__________________________________________________________________________    Tensile         Tensile               % Coating    Strength         Strength               Weight                     Elmendorf    Machine         Cross Loss  Tear    Direct-         Direct-               During                     Machine                            ElmendorfEx.   Descrip-    ion  ion   Condition-                     Direc- Tear Cross#  tion  (KPa)         (KPa) ing   tion   Direc-tion__________________________________________________________________________65 100%  2061 1131  10.1  63(5)  95(7)   AIRVOL   16566 99%   2186 1496  8.9   79(2)  100+   AIRVOL   165:1%   Syn67 95%   2029 1427  8.4   74(7)  89(0)   AIRVOL   165:5%   Syn68 90%   2475 1799  7.8   75(4)  86(7)   AIRVOL   165:10%   Syn69 80%   2109 1510  6.2   100+   95(4)   AIRVOL   165:20%   Syn70 100% Syn    2661 1979  5.5   100+   91(0)__________________________________________________________________________
TABLE 19__________________________________________________________________________                     Water               Total Absorption/                            Effective               Water Dry wt.                            WaterEx.   Descrip-    Wet Out         % Water               Absorption                     of Sample                            Absorption#  tion  (sec)         Loss  (g/ft2)                     (g/g)  (g/ft2)__________________________________________________________________________65 100%  0    17.4  134.52                     7.92   99.60   AIRVOL   16566 99%   0    20.0  150.09                     8.38   112.50   AIRVOL   165:1%   Syn67 95%   0    15.0  136.17                     7.81   99.90   AIRVOL   165:5%   Syn68 90%   0    14.8  130.50                     7.63   95.40   AIRVOL   165:10%   Syn69 80%   0    15.8  131.58                     7.14   94.80   AIRVOL   165:20%   Syn70 100   2    16.8  143.25                     7.33   106.71   Syn__________________________________________________________________________
Examples 71-83
These examples demonstrated the use of syndiotactic polyvinyl alcohol with chemical crosslinkers (Tyzor LA and/or glyoxal) in wiping articles according to the invention. Curing conditions were 3.5 hr at 150� F. (65.5� C.). Mole % crosslinking amounts for Tyzor LA were based on four bonds between titanium and polyvinyl alcohol. Mole % crosslinking amounts for glyoxal were based on four bonds between glyoxal and polyvinyl alcohol.
TABLE 20__________________________________________________________________________                     Water               Total Absorption/                            Effective               Water Dry wt.                            WaterEx.   Descrip-    Wet Out         % Water               Absorption                     of Sample                            Absorption#  tion  (sec)         Loss  (g/ft2)                     (g/g)  (g/ft2)__________________________________________________________________________71 1% Blend    0    25.1  129.2 8.65   119.49   of Syn in   Airvol 165   with 20   mol %   Tyzor LA   crosslinking72 1% Blend    0    20.1  137.4 8.12   117.36   of Syn in   Airvol 165   with 20   mol %   Tyzor LA   crosslinking73 5% Blend    0    16.9  134.7 7.71   106.92   of Syn in   Airvol 165   with 20   mol %   Tyzor LA   crosslinking74 5% Blend    0    17.8  135.2 7.62   108.00   of Syn in   Airvol 165   with 20   mol %   Tyzor LA   crosslinking75 10% Blend    0    21.7  128.4 7.96   110.28   of Syn in   Airvol   165 with 20   mol %   Tyzor LA   crosslinking__________________________________________________________________________
TABLE 21__________________________________________________________________________                     Water               Total Absorption/                            Effective               Water Dry wt.                            WaterEx.   Descrip-    Wet Out         % Water               Absorption                     of Sample                            Absorption#  tion  (sec)         Loss  (g/ft2)                     (g/g)  (g/ft2)__________________________________________________________________________76 10% Blend    0    18.2  133.8 7.70   108.2   of Syn in   Airvol   165 with 20   mol %   Tyzor LA   crosslinking77 1% Blend    0    15.6  137.8 8.42   107.7   of Syn in   Airvol   165 with 40   mol %   Glyoxal   crosslinking78 1% Blend    0    17    139.4 8.58   111.4   of   Syndio-   tactic   in Airvol   165 with 40   mol %   Glyoxal   crosslinking79 5% Blend    0    15.8  145.4 8.35   114.7   of   Syndio-   tactic   in Airvol   165   with 40   mol %   Glyoxal   crosslinking80 5% Blend    0    17.3  139.7 8.80   113.3   of   Syndio-   tactic   in Airvol   165   with 40   mol %   Glyoxal   crosslinking81 10% Blend    0    11.2  144.5 8.40   107.1   of   Syndio-   tactic   in Airvol   165   with 40   mol %   Glyoxal   crosslinking82 10% Blend    0    16.9  154.8 8.30   122.3   of   Syndio-   tactic   in Airvol   165   with 40   mol %   Glyoxal   crosslinking83 10% Blend    0    13.1  141.9 7.46   105.2   of   Syndio-   tactic   in Airvol   165__________________________________________________________________________
TABLE 22______________________________________             Tensile   Tensile             Strength  Strength                              % Coating             Machine   Cross  Weight Loss             Direction Direction                              DuringEx. # Description (KPa)     (KPa)  Conditioning______________________________________71    1% Blend of 2158      2082   4.3 Syn in Airvol 165 with 20 mol % Tyzor LA crosslinking72    1% Blend of 2971      1724   4.2 Syn in Airvol 165 with 20 mol % Tyzor LA crosslinking73    5% Blend of 2572      2199   4.4 Syn in Airvol 165 with 20 mol 5 Tyzor LA crosslinking74    5% Blend of 2737      1979   4.5 Syn in Airvol 165 with 20 mol % Tyzor LA crosslinking______________________________________
TABLE 23______________________________________             Tensile   Tensile             Strength  Strength                              % Coating             Machine   Cross  Weight Loss             Direction Direction                              DuringEx. # Description (KPa)     (KPa)  Conditioning______________________________________75    10% Blend of             2475      1944   5.1 Syn in Airvol 165 with 20 mol % Tyzor LA crosslinking76    10% Blend of             2910      2240   4.8 Syn in Airvol 165 with 20 mol % Tyzor LA crosslinking77    1% Blend of 2820      1889   3.3 Syn in Airvol 165 with 40 mol % Glyoxal crosslinking78    1% Blend of 2351      --     3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking79    5% Blend of 2492      2006   3.2 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking80    5% Blend of 2199      1841   3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking81    10% Blend of             2227      1696   3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking62    10% Blend of             2379      1786   3.0 Syndiotactic in Airvol 165 with 40 mol % glyoxal crosslinking83    10% Blend of             2365      1696   1.8 Syndiotactic in Airvol 165______________________________________
Examples 84-86 demonstrated the effect of coat weight on wiping parameters of articles made in accordance with General Procedure IV. A binder precursor solution consisting only of 30% syndiotactic PVA was coated onto nonwoven substrates at various coating weights (i.e., 1 g, 2 g, 5 g total PVA in coating solution) as indicated in Tables 24 and 25, which also present the absorbency and strength test results.
TABLE 24__________________________________________________________________________    Tensile         Tensile               %    Strength         Strength               Weight                     Elmendorf    Machine         Cross Loss  Tear    Direct-         Direct-               During                     Machine                            ElmendorfEx.   Descrip-    ion  ion   Condition-                     Direc- Tear Cross#  tion  (KPa)         (KPa) ing   tion   Direction__________________________________________________________________________84 5 g:100%    2661 �         1979 �               5.5   100+   91 � 0   Syn   117  6985 2 g:100%    2006 �         1351 �               3.3   75 � 6                            96 � 2   Syn   131  3486 1 g:100%    1441 �         1186 �               2.9   84 � 9                            100+   Syn   138  89__________________________________________________________________________
TABLE 25__________________________________________________________________________                     Water               Total Absorption/                            Effective               Water Dry wt.                            WaterEx.   Descrip-    Wet Out         % Water               Absorption                     of Sample                            Absorption#  tion  (sec)         Loss  (g/ft2)                     (g/g)  (g/ft2)__________________________________________________________________________84 5 g:100%    2    16.8  143.25                     7.33   106.71   Syn85 2 g:100%    0    18.2  146.31                     8.31   116.40   Syn86 1 g:100%    0    20.5  157.68                     10.43  127.62   Syn__________________________________________________________________________
Examples 87-89
Examples 87-89 demonstrated the results of direct ammonolysis of polyvinyl trifluoroacetate after the binder precursor solutions was coated on the nonwoven substrate. The absorbency and strength of these articles (Tables 26 and 27) were superior to those of 30% syndiotactic polyvinyl alcohol coated from water described in the preceding examples. One explanation of the benefits observed is that acid catalyzed loss of syndiotacticity was minimized by use of this method which probably provided greater surface area for ammonolysis.
TABLE 26______________________________________             Tensile   Tensile             Strength  Strength                              %             Machine   Cross  Weight Loss             Direction Direction                              DuringEx. # Description (KPa)     (KPa)  Conditioning______________________________________87    16 g        3744      3041   0 PVTFA/ ammonolyzed (5 g PVA)88    6.5 g       2544      2082   0 PVTFA/ ammonolyzed (2 g PVA)89    3.2 g       1551      1165   0 PVTFA/ ammonolyzed (1 g PVA)______________________________________
TABLE 27__________________________________________________________________________                     Water               Total Absorption/                            Effective               Water Dry wt.                            WaterEx.   Descrip-    Wet Out         % Water               Absorption                     of Sample                            Absorption#  tion  (sec)         Loss  (g/ft2)                     (g/g)  (g/ft2)__________________________________________________________________________87 16 g  0    22.5  114.4 5.86    81.5   PVTFA/   ammono-   lyzed   (5 g PVA)88 6.5 g 0    23.0  143.2 7.90   107.6   PVTFA/   ammono-   lyzed   (2 g PVA)89 3.2 g 0    30.1  166.2 9.82   134.1   PVTFA/   ammono-   lyzed   (1 g PVA)__________________________________________________________________________
This example demonstrated the preparation of a bactericidal wipe based on iodine and the polyvinyl alcohol/polyiodide complex utilizing General Procedure IV. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g water was prepared. This solution was coated onto a sample of a wipe as prepared in Examples 84-86. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water iodine color and odor were plainly evident.
A sample containing 5 g 30% syndiotactic PVA as the only binder Component in 200 g total solution was prepared and coated as in Examples 84-86 containing 0.1 g "Orcobrite Blue 2GN" pigment (Organic Dyestuffs Corp., Concord, N.C.). The sample was cured at 250� F. (121� C.) for 2 hours. The sample discolored slightly and had a strong odor, but was colorfast after conditioning in luke-warm water for 2 hours.
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Ltd.A lyocell fiber with modified property and a process for making therefor* Cited by examiner, † Cited by third partyClassifications U.S. Classification427/243, 427/430.1, 427/427.6, 427/428.2, 427/439, 427/322International ClassificationD04H1/64, D06M101/02, D06M101/30, D06M101/00, D06M15/333, D06M13/02, D06M101/06, D06M101/16, D06M101/32, D06M13/503, D06M101/18, D06M15/356Cooperative ClassificationD04H1/64, D04H1/587, D04H1/643, Y10T442/2861, Y10T442/20, Y10T442/676, Y10T442/2877, Y10T442/2369, Y10T442/60, Y10T442/2352European ClassificationD04H1/64A, D04H1/64CLegal EventsDateCodeEventDescriptionMay 5, 1997ASAssignmentOwner name: MINNESOTA MINING AND MANUFACTURING COMPANY, MINNESFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TRUONG, JACK;STUDINER, WILLA M.;REEL/FRAME:008486/0697Effective date: 19930528Mar 6, 2001REMIMaintenance fee reminder mailedAug 12, 2001LAPSLapse for failure to pay maintenance feesOct 16, 2001FPExpired due to failure to pay maintenance feeEffective date: 20010812RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services