Patent Application
20050252628
The invention relates to an improvement in compositions used in treatments for paper, fiber, nonwoven, textile, and carpets and in firefighting foam compositions. The invention is particularly useful for stabilizing treatment ingredients that impart grease, oil, and water resistance to a treated substrate. The present composition is particularly suitable for aqueous treatments that impart or enhance oil, grease, and water resistance to the finished product.
Fluorochemicals of one or more types are used to impart resistance to grease, oil, and water. See, U.S. Pat. Nos. 4,590,129; 5,252,754; 5,492,599; 5,674,961; 6,218,464 and published U.S. application Ser. No. 2003/0217824, the disclosures of which are herein incorporated by reference.
Multiple tests have been devised to measure and evaluate fluorochemical treatments of paper. See, U.S. Pat. No. 5,674,961. One common test is known as the “Kit Test” (TAPPI T559 cm-02), so-called due to the form in which the 12 formulations containing castor oil, heptane, and toluene are provided.
Paper products are provided with enhanced grease and oil resistance by treatment of the paper fibers with one or more fluorochemical compounds. The treatment process can be incorporated into the paper fibers by adding the fluorochemical during a wet end processing stage (i.e., where the pulp is still in slurry form before formation and drying) in the paper manufacturing process. The treatment process may be applied to the formed paper, before, during, or after any of the forming or drying stages, such as surface starch sizing application systems or water repellent size finishing systems. Treatments employing one or more of the above application strategies are also possible.
Effective fluorochemical compounds used in grease- and oil-resistant treatments are very expensive. Because the grease-proofing market is highly competitive, intolerant of failure, and constantly in search of technological advantages that provide a meaningful competitive advantage, there exists a continuing need for improvements that make better use of the applied fluorochemical grease- and oil-proofing compounds.
It is an objective of the invention to provide an improved fluorochemical treatment composition that comprises: (a) an fluorochemical compound that imparts grease and oil resistance to a treated substrate; and (b) a water soluble dispersant extender having a cyclic molecular structure with relatively hydrophobic interior cavity that is attractive to said fluorochemical compound and a relatively hydrophilic exterior shell.
The water soluble dispersant extender of the invention enhances the effectiveness of the applied fluorochemical compound. By using the present water soluble dispersant extender, an inclusion complex is formed whereby enhanced dispersion and solubility over the surface of the substrate allows more efficient use of the fluorochemical compound so that either less fluorochemical compound can be used to achieve the same level of grease and oil resistance or the same proportions of fluorochemical compound can be used for greater grease and oil resistance.
It has now been found that the oil and grease resisting properties of conventional agents imparting grease and oil resistance to a substrate may be extended, i.e., similar grease and oil resistant properties may be achieved using smaller quantities of the expensive active ingredient compound when employed with the dispersant extenders disclosed herein. If the same amount of active ingredient compound is used, the grease and oil resistance properties of the treated substrate are improved relative to the use of the same active ingredient composition but without the dispersant extender.
Preferred active ingredients for imparting grease and oil resistance are generally fluorine-based compounds and are conventionally used in the papermaking industry as finishing agents that can be added to the wet end of the process or to a post-formation finishing process. Exemplary fluorochemical treatment agents include those described in U.S. Pat. Nos. 3,997,500; 4,590,129; 5,252,754; 5,674,961; and 6,300,409 the disclosures of which are herein incorporated by reference. Fluorocarbon chemical compounds which are generally suitable as oil- and water-repellents are those polymeric materials which have a polar head (to interact with the reactive fiber) and a fluorocarbon non-polar tail (which is both oleophobic and hydrophobic, thereby imparting stain resistance to both organic compounds, such as oils, and water). Several of types anionic molecules also are used for sizing, with comparatives studies being mentioned in examples. These compounds are generally referred to as fluorocarbon chemicals, fluorocarbon finishing agents, polymeric fluorocarbons, fluorochemical finishing agents and fluorocarbons. Such terms are used interchangeably herein, all of them referring to fluorocarbon chemicals which are useful in imparting oil-, water-, and stain-repellency to substrates.
Dispersant extenders useful in the present invention are water soluble macromolecular host compounds or inclusion complexes that are characterized by a cyclic molecular structure having a relatively hydrophobic interior cavity and a relatively hydrophilic exterior shell. See, U.S. Pat. Nos. 5,358,998; 6,358,431; and 6,541,564, which are herein incorporated by reference. The relatively hydrophobic interior cavity space becomes associated with the fluorochemical compound by solubility, chemical attraction, or other forces. The relatively hydrophilic exterior shell provides water solubility that enhances the dispersion and wetting of the associated fluorochemical. Relative hydrophobicity and hydrophilicity may be found in the structure of the molecule, from the moieties pendant from the cyclic backbone, or from moieties substituted into the cyclic backbone.
For stability in the final product and compatibility across a wide variety of substrates, generally preferred dispersants according to the present are molecules or salts thereof that contain only carbon, oxygen, and hydrogen atoms in the cyclic backbone structure of the dispersant molecule. It is, however, within the scope of the invention to provide moieties and backbone molecules that are not limited to carbon, hydrogen, or oxygen atoms when the resulting molecule does not adversely affect the treated substrate.
Examples of suitable dispersants include clathrates generally and particularly cyclic oligosaccharides such as cyclodextrins including roasted dextrins and sugared starches such as those described in U.S. Pat. No. 5,358,998, quaternized cyclodextrin, cycloamylose, cycloglucans, cyclic oligoglucosides containing 5 to about 10 glucose residues in which an enclosed tubular space allows reception of a guest molecule to form a clathrate (Schardinger dextrins), naturally occurring clathrates, and calixarenes.
Preferred cyclodextrins include alpha-cyclodextrin, a beta-cyclodextrin, a gamma-cyclodextrin, or cyclodextrin substituted by an ester, alkyl, ether, hydroxyalkylether, dihydroxyalkylether, alkoxycarbonylalkylether, carboxyalkylether, glucosyl, or maltosyl. Specific examples include alpha-, beta- and gamma-cyclodextrins, and their ester-, alkyl ether-, hydroxyalkyl ether-, alkoxycarbonyl alkyl ether-, sulfonate alkyl ether- and carboxyalkyl ether-derivates and salts thereof, e.g., methyl-alpha-cyclodextrin, methyl-beta-cyclodextrin, methyl-gamma-cyclodextrin, ethyl-beta-cyclodextrin, butyl-alpha-cyclodextrin, butyl-beta-cyclodextrin, butyl-gamma-cyclodextrin, 2,6-dimethyl-alpha-cyclodextrin, 2,6-dimethyl-beta-cyclodextrin, 2,6-dimethyl-gamma-cyclodextrin, 2,6-diethyl-beta-cyclodextrin, 2,6-dibutyl-beta-cyclodextrin, 2,3,6-trimethyl-alpha-cyclodextrin, 2,3,6-trimethyl-beta-cyclodextrin, 2,3,6-trimethyl-gamma-cyclodextrin-, 2,3,6-trioctyl-alpha-cyclodextrin, 2,3,6-trioctyl-beta-cyclodextrin, 2,3,6-triacetyl-alpha-cyclodextrin, 2,3,6-triacetyl-beta-cyclodextrin-, 2,3,6-triacetyl-gamma-cyclodextrin, (2-hydroxy)ethyl-beta-cyclodextrin, (2-hydroxy)propyl-alpha-cyclodextrin, (2-hydroxy)propyl-beta-cyclodextrin, (2-hydroxy)propyl-gamma-cyclodextrin, partially or peracetylated, methylated and succinylated alpha-, beta- and gamma-cyclodextrin, 2,6-dimethyl-3-acetyl-beta-cyclodextrin and 2,6-dibutyl-3-acetyl-beta-cyclodextrin, randomly methylated alpha-, beta- and gamma-cyclodextrin, randomly or selective sulfopropylated- or sulfobutylated alpha-, beta- and gamma-cyclodextrin. Beta-cyclodextrin (bCD) and beta-cyclodextrin derivatives are particularly preferred. In some cases, bCD may also impart enhanced brightness to treated substrates.
The quaternization of beta-cyclodextrin is done commercially in one of a few ways. The primary way is by reaction of the cyclodextrin with either glycidyltrimethylammonium chloride (e.g., U.S. Pat. No. 5,728,823) or 3-chloro-2-hydroxypropyltrimethylammonium chloride (commonly referred to as chlorohydrin) in presence of caustic. See also U.S. Pat. No. 4,547,572).
Exemplary calixarenes that can be used include those described in U.S. Pat. Nos. 6,271,337; 6,358,431; and published U.S. patent application Ser. No. 2003/212301, the disclosures of which are herein incorporated by reference.
Dispersant extenders are used in an amount sufficient to facilitate dispersion of the fluorochemical agent without adversely affecting the properties of the resulting product. Generally, the optimum amount or range of added dispersant extender will reflect an enhanced effectiveness of the fluorochemical agent as determined by comparative tests of products treated with the same fluorochemical but either with or without the dispersants identified herein. Suitable amounts will be within the range from about 1 ppm to about 6 wt % on fiber based on said fluorochemical composition applications, preferably from about 10 ppm to about 2000 ppm based on said fluorochemical composition, and most preferably within the range from about 25 ppm to about 1000 ppm.
Substrates that can be treated with the composition and method of the present invention include virtually any material that can be wet with an aqueous solution and in which enhanced resistance to grease and oil is desired. Suitable substrates that can benefit from the present invention include paper, fiber, nonwoven materials, textiles, carpets and carpet fibers.
In a starch sizing tank that feeds into a surface size press processing stage of a paper manufacturing process is batch cooked highly acid thinned hydroxyethylated starch. The water hardness is determined to be 0 ppm total hardness as CaCO3 without chelation. An oil and grease repellant composition containing a mixture of 80% di(perfluoro alkyl ethyl) phosphate ester diethanolamine salt and 20% mono perfluoroalkyl ethyl phosphate ester diethanolamine salt was used at rates of 0.20% actives in solution and was mixed into the starch sizing solution to make a finishing solution that was added to a size press at a usage rate of 350 cc/min along with 33.5 liter/min of hydroxyethylated starch makeup with about 50% starch solution pick up. Starch tank application system averaged 60° C. A sample of paper was taken from the rewinder after it was pressed and dried on the fourdrinier paper machine. Sample was tested for grease and oil resistance using a TAPPI T559 cm-02 test kit. The results of the testing provided a rating of 5 wire side/6 felt side.
Powdered beta-cyclodextrin was dissolved in 25° C. water and then added to a starch sizing tank with constant agitation at the rate. The solution was allowed to dissolve over a twenty minute period in a holding tank at a 1% dilution using and applied at a rate of 300 cc/min (about 150 ppm on make up starch). The starch sizing tank had a 10 minute turnover rate based on constant level control. As before with the same application rate of finishing solution, the treated pulp was formed into paper, dried and tested for grease and oil resistance. The kit test results gave a rating of 6 wire side/7 felt side. This improved grease and oil resistance was attributed to more efficient use of the oil and grease repellant composition because beta-cyclodextrin is not known to provide inherent grease and oil repellant characteristics to paper.
Additional tests were performed on both samples using hot corn oil (MAZOLA™ brand vegetable oil) commonly use on potato French fries. Exposure to oil at 105° C. for 10 minutes showed a clear performance advantage, little or no staining with the sample treated with beta-cyclodextrin. In addition, spray canola (PAM™ brand cornola oil) showed a performance preference to the beta-cyclodextrin treated papers.
A further set of tests reduced the rate of applied oil and grease repellant formulation from a usage rate of 350 cc/min to 250 cc/min. The paper treated with this reduced rate of oil and grease repellant composition gave a kit rating of 5 wire side/6 felt side and corresponded with a application specific 30% reduction in the rate of fluorochemical usage.
On reduction of about 30% fluorochemical usage in co-application with beta-cyclodextrin, showed similar visual staining amounts as compared to samples without beta-cyclodextrin and increased fluorochemical consumption.
One kilogram of Beta-Cyclodextrin was slurried in a 20 liter pail of 40° C. deionized water which dissolved clear, leaving behind a slight amount of residue.
The beta-cyclodextrin slurry was then added as a size press additive on a fourdrinier paper machine by directly pouring into a starch run tank with a known turn over of 15 minutes. Addition was made to approximate 8 minutes before a reel turn up on the dry end. The beta-cyclodextrin was used in conjunction with a di(perfluoroalkyl)ethyl phosphate ester, diethanolamine salt added by individual metering pump at 1000 cc/min.
Prior to beta cyclodextrin addition, off machine test kit response was 7 wire side/7 felt side. Beta-cyclodextrin addition moved the kit response to 8 wire side/8 felt side. Corresponding reduction is estimated at 25%. In light of the relative costs of beta-cyclodextrin and fluorochemical oil and grease repellant composition, the beta-cyclodextrin provides a cost effective extender for fluorochemical-based oil and grease repellants.
Efficacy of beta-cyclodextrin in a pilot fourdrinier machine paper laboratory was evaluated in the next several examples with commercially available aqueous dispersions of fluorochemicals. Using the paper industry standard compositions of hydroxyethylated starches, aqueous dispersions of commercially available fluorochemicals, and chelating agents, beta-cyclodextrin was substituted to demonstrate effect.
Acid thinned hydroxyethylated corn starch was batch cooked at 15% solids and cut to 5% solids prior to size press applications. 20 liter solutions of 5% hydroxyethylated starch used 10 gm of ethylenediamine tetraacetic acid (EDTA) chelating agent, 0.2% wt by actives of copolymers of 2-perfluoroalkylethyl acrylate, 2-N,N-diethylaminoethyl methacrylate, and glycidyl methacrylate replaced the fluorochemical formulation used in example 1. Tests with the TAPPI T559 cm-02 showed repellence scores of 7 wire side/7 felt side.
The addition of 1.5 gm (75 mg/l) of powdered beta-cyclodextrin was dissolved in starch by agitation in 20 liters. Resulted in improved scores to 9 wire side/8 felt side by TAPPI Method T559 cm-02.
The reaction products of glycine, N,N-bis-2-hydroxy-3-(2-propenyloxy) propyl-, monosodium salt, with ammonium hydroxide and pentafluoroiodoethane-tetrafluoroethylene telomer (CAS Reg. No. 220459-70-1) were used instead of the fluorochemical active ingredients used in example 1 in the finishing solution. The fluorochemical was introduced to the slurry at the rate of 0.2% actives in solution. Tests with the TAPPI T559 cm-02 test kits gave scores of 7 wire side/7 felt side.
The addition of 300 ppm of beta-cyclodextrin to the finishing solution improved the ratings to 8 wire side/8 felt side. As with example 1, it is believed that the improved resistance ratings were due to an enhanced efficiency in the dispersion of the applied fluorochemical composition.
The reaction products of 3-cyclohexane-1-carboxylic acid, 6-((di-2-propenylamino)carbonyl)-,(1R,6R) with pentafluoroiodoethane-tetrafluoroethylene telomer, ammonium salts replaced the fluorochemical composition used in example 1.
The fluorochemical active ingredients was used at the rate of 0.2 wt % in solution. Tests with the TAPPI T559 cm-02 tests gave results of 7 wire side/7 felt side.
The addition of 75 ppm of beta-cyclodextrin to the finishing solution improved kit test results to a 9 wire side/8 felt side. Such improvements in repellency would allow a reduction in the usage rate of fluorochemical oil and grease repellant composition.
The reaction products of (a) 2-propen-1-ol, (b) pentafluoroiodoethane-tetrafluoroethylene telomer, (c) dehydroiodinated, (d) reaction products with epichlorohydrin and triethylenetetramine (CAS Reg. No. 464-178-90-3) was used by means of producing a representative sample.
The fluorochemical extender beta-cyclodextrin was replaced with alpha-cyclodextrin, hydroxypropyl beta-cyclodextrin 4.5 DS; hydroxypropyl beta-cyclodextrin 6.5 DS; beta-cyclodextrin, sulfated, sodium salt (CAS 37 191-69-8); and beta-cyclodextrin, tri-acetyl (CAS 23739-88-0).
Tri-acetyl beta-cyclodextrin exhibited such a low soluble in water (similar to acetyl substitution on amylose) that its usefulness as a fluorochemical extender in aqueous systems would be minimal.
Alpha-cyclodextrin, six unit cyclical glucan and gamma-cyclodextrin, eight unit cyclical glucan were used as alternate extenders. The efficacies of each were similar to that seen with beta-cyclodextrin. However, the increased costs of these materials relative to beta-cyclodextrin would make commercial use prohibitive.
Sulfated beta-cyclodextrin was also used in a similar manner as described in prior examples. It was noted that this compound was highly soluble in aqueous systems, and its effectiveness was verified as an appropriate inclusion compound for use as a fluorochemical extender.
The following examples demonstrate the efficacy of beta-cyclodextrin as an additive to wet end of aqueous fiber systems. Beta-cyclodextrin (150 ppm) was added to a 0.5% solids pulp slurry containing 50% hardwood fibers, and 50% softwood fibers refined to 310 Canadian Standard Freeness.
Based on 1.2 gram handsheets, 0.3% Nalco 7607 was added on fiber, along with 0.2% actives fluorochemical on fiber, followed by 0.05% Nalco 625 on fiber. Nalco 625 is believed to be a polymeric product of apidic acid and epichlorhydrin. Nalco 7607 is believed to be a 100% substituted polyamine. An additional set was made from a pulp slurry without beta-cyclodextrin (“bCD”) for control purposes, using 0.3% Nalco 7607, 0.2% fluorochemical, and 0.05% Nalco 625. The results are listed in the table below.
A matrix chart of wet end beta-cyclodextrin derivatives is included in Table 2 showing their efficacy as extenders for grease proofing fluorochemical compounds. The fluorochemical/cyclodextrin complex was heated to 60° C. and cooled felt side down to ambient temperature to confirm stability in solution. Some complexes precipitated and some did not. The precipitating complexes were not generally effective.
Handsheet samples were made by adding 0.5 ml of Nalco 7607 (a low molecular weight cationic retention aid), a quantity of the fluorocarbon/cyclodextrin complex, and 1 drop of 1% Nalco 625 (high molecular weight anionic flocculating agent). The efficacy of each treatment on paper was determined using the industry standard 3M/TAPPI test kit solutions and reported in Tables 2-5 below. Results from multiple samples are reported as separated by commas.
The following abbreviations apply: CD=cyclodextrin; bCD=beta-cyclodextrin; HPbCD=(2-hydroxy)propyl-beta-cyclodextrin; HEbCD=(2-hydroxy)ethyl-beta-cyclodextrin; CMbCD=carboxymethyl-ether-beta-cyclodextrin; and Quat-bCD=quarternized beta-cyclodextrin using 3-chloro-2-hydroxypropyltrimethylammonium chloride.
The results in Tables 2-5 show that treatment of paper with one or more types of fluorocarbon-cyclodextrin extender complexes can result in enhanced grease and oil resistance.
