Process for fiber treatment
United States Patent [191 Pattison [451 Apr. 29, 1975 PROCESS FOR FIBER TREATMENT [75] Inventor: Victor A. Pattison, Tonawanda,  
 [73] Assignee: Hooker Chemicals &amp; Plastics Corporation, Niagara Falls, NY.  
 [22] Filed: Jan. 12, 1973 [21] Appl. No.: 323,177  
 [52] US. Cl. 162/167; 260/295 AM; 260/295 CA [51] Int. Cl D21h 3/12 [58] Field of Search. 260/295 CA, 295 C, 295 Q,  
 [56] References Cited UNITED STATES PATENTS 2,518,266 8/1950 Baird et a1. 260/295 AM 2,518,267 8/1950 Baird et a1 260/295 AM Primary Examiner-Robert L. Lindsay, Jr.  
 Assistant ExaminerWilliam F. Smith Attorney, Agent, or Firm-Peter F. Casella; John M. Petruncio [57] ABSTRACT Compositions of the formula are used to impart wet-strengthening and waterrepellency properties of fibers and fibrous materials.  
 8 Claims, No Drawings PROCESS FOR FIBER TREATMENT This invention relates to the treatment of fibrous materials. More particularly, this invention relates to the improvement of wet strength and water repellency characteristics of paper and paper products.  
 For many years, no commercially available wet&#39; strength resins were available which would function effectively at pHs much above about 5.5. As a consequence, many grades of paper and paper products made on the alkaline side for various reasons, including strength, softness, use of alkaline fillers or the like, could not be effectively wet-strengthened.  
  Attempts to allievate this and other problems have been made in the past. Recently, the wet-strengthening of paper and paper products by the use of polymeric reaction products of epichlorohydrin and polyamides derived from polyalkylene polyamines and saturated aliphatic dicarboxylic acids containing from 3 to carbon atoms has been prepared. Such resins have been proposed for use under pH conditions on the alkaline side in the production of alkaline papers, and in applications to fibers while the fibers are in dilute aqueous suspensions of the consistancy generally used in paper mills.  
  It is also known to produce paper having a measure of wet strength by mixing fibrous pulp with suspensions of polyvinyl alcohol, or with latex, and to produce paper from the thus formed mixture.  
  Unsaturated aliphatic dibasic acids, reacted with ammonia, a polyamine and epichlorohydrin have also been proposed for use in imparting wet strength to paper and paper products. However, universal acceptance of the wet-strengthening materials of the prior art has been less than total.  
  It is an object of the present invention to provide paper products having improved wet strength and water repellency characteristics.  
 This and other objects and advantages of the present invention will become apparent from a reading of the description which follows and the appended claims.  
  Briefly stated, the wet strength and water-repellency characteristics of fibrous materials, such as paper and paper products, are improved by treating such materials with resinous treating materials of the formula wherein R, R and R are organic radicals generally having from 1 to about 12 carbon atoms; R, is an alkyl radical having from about 5 to about 24 carbon atoms; X is halogen; a, b and c are numbers having a value of from zero to 3; x is a number having a value of from about 1 to about 10 and y is a number having a value of from about 0.8 to about 4.  
  The fibers which may be treated in according with the process of the present invention include textile and paper fibers, and the process is particularly useful in treating paper pulp and paper products.  
 According to the process of the present invention,  
 the fibrous materials are treated by applying thereto the resins hereinbefore as aqueous dispersions, generally the dispersions containing from about 0.1 to about 10 percent by weight resin, preferably from about 1 to about 5 weight percent. The dispersions may contain the resins in greater amounts; however, it has been found that subjecting the fibrous materials to treatment with aqueous dispersions of resin containing from about 1 to about 5 percent by weight resin, for a time sufficient to provide an addon of resin from about 0.2 to about 2 percent by weight, preferably from about 0.2 to about 1.5 percent by weight, based on the dry weight of the fibrous material treated.  
  The dispersion may be added to the material to be treated by any method known to the art. The dispersions are particularly suited to the treatment of paper pulp. In treating pulp, the dispersion is added to the pulp slurry, with stirring, in amounts to obtain the desired addon, the pulp is sheeted out by conventional methods and dried.  
  The resins utilized in treating the fibrous materials, as stated, are those of the formula:  
 wherein R, R and R are organic radicals generally having from 1 to about 12 carbon atoms; R is an alkyl radical having from about 5 to about 24 carbon atoms; X is halogen; a, b and c are numbers having a value of from zero to 3; x is a number having a value of from about 1 to about and y is a number having a value of from about 0.8 to about 4.  
  The molecular weight of the resins may vary from about 500 to&#39;about 2,500, or higher.  
  The resins used in the present process are prepared by:  
  a. N-methyl aniline, or a substituted N-methyl anilines, or mixtures thereof are condensed with formaldehyde and a non-N-substituted aniline or mixtures thereof;  
  b. the resin obtained from (a) is reacted with a carbonic dihalide to convert the N-methyl amino groups to carbamoyl halide groups and the amino groups to isocyanate groups;  
  c. the resin of (b) is reacted with a C C alcohol at the isocyanate sites; and  
  d. the resin of (c) is reacted with pyridine N-oxide, substituted pyridine N-oxides, or suitable mixtures thereof to obtain the resins.  
  Suitable carbonic dihalides are phosgene, carbonic dibromide, and the like. Preferably, phosgene is the carbonic dihalide utilized.  
 Suitable N-methyl anilines for use in formulating the resinous compositions of the present invention include N-methyl aniline; 3,5-dimethyl N-methyl aniline; 4- dodecyl N-methyl aniline; 4-phenyl N-methyl aniline; 4-naphthyl N-methyl aniline; 3-(2-chloro) propyl N- methyl aniline; 3,4,5-trimethyl N-methyl aniline, and the like, as well as a mixtures thereof. The most preferred N-methyl aniline is the unsubstituted N-methyl anilines.  
  Suitable pyridine N-oxides for formulating the resinous compositions of the present invention include 3,5- dimethyl pyridine N-oxide; 3,5-dipropyl pyridine N- oxide; 3-methyl pyridine N-oxide; 4-naphthyl pyridine N-oxide; 4-phenyl pyridine N-oxide; 3-hexyl pyridine N-oxide; 4-(3-chloropropyl) pyridine N-oxide and the like, or mixtures thereof. The most preferred reactant is unsubstituted pyridine N-oxide.  
  The formaldehyde employed may be obtained from such sources as aqueous solutions of formaldehyde, trioxane, paraformaldehyde, and the like. Preferably, the formaldehyde is used as an aqueous solution, about 37 percent by weight formaldehyde. v  
  Suitable non-N-substituted anilines useful in preparing the resins of the present invention include 3,5- dimethyl aniline; 3,5-dipropyl aniline; 4-phenyl aniline; 4-naphthyl aniline; 4-(4-chloro phenyl) aniline; 3-hexyl aniline; 4-dodecylaniline and the like, or mixtures thereof. The most preferred reactant is unsubstituted aniline.  
  The reaction of the aniline compound, the N-methyl aniline compound and formaldehyde is conducted by adding the fomaldehyde on a continuous basis to the aniline compounds in a system acidified to a low pH of a suitable mineral acid such as hydrochloric acid, the formaldehyde added in sufficient amounts to effect condensation of the anilines present. Following the addition of the formaldehyde, the reaction mixture is made alkaline by the addition thereto of a suitable alkaline agent, as for example, aqueous sodium hydroxide,  
 a solid product separating. The liquid phase is removed by decantation, and the residue heated to remove any remaining water. The pH of the reaction system, during the addition of the formaldehyde, is generally maintained at l or less.  
  The temperature during the step (a) reaction is generally maintained at from about to about 160C, preferably from about 130 to about 160C, with the time required to effect the condensation being on the order of from about 60 to about 90 minutes.  
  The reaction product of step (a) is then reacted with the selected carbonic dihalide, preferably phosgene, by adding a suitable solvent to the resin, heating to temperatures sufficient to remove any water present, cooling to less than about 35C, and adding the carbonic dihalide continuously, in about stoichiometric amounts to react with the N-methyl amino groups, converting the groups to carbamoyl chloride groups, and the amino groups to isocyanate groups.  
  Heat is applied to move the temperature gradually up to about 150C, evolving hydrochloric acid. The temperature is generally moved through a range of from about 35 to about 150C over a period of about 90 minutes. The solvent is removed by distillation, generally at about C under reduced pressures.  
  Suitable solvents include the halogenated hydrocarbons, such as chlorobenzene, dichlorobenzene and the like.  
  Generally the reaction is completed within a period of from about 90 to 120 minutes.  
  The product of step (b) is then reacted with the fatty alcohol by adding the alcohol, with stirring, to the resin in amounts sufficient to convert the isocyanate groups to carbamoyl ester groups, generally at a temperature of about 90C, the reaction being essentially completed within a period of about 30 minutes.  
  The reaction product from step (c) is then reacted with the selected pyridine N-oxide by adding the pyridine N-oxide in about stoichiometric amounts, based on the carbamoyl halide groups present, stirring and allowing the reaction mixture to stand for about 2-8 hours, maintaining the temperature at ambient temperatures; however, the reaction may be conducted at elevated temperatures, on the order of about 90C.  
 EXAMPLE 1 N-methyl aniline (257 parts by weight) is condensed with aniline (149 parts by weight) and formaldehyde at a pH of about 1 and at a temperature of about C. The reaction product is added to dichlorobenzene and heated to remove water-present. Phosgene is added to the reaction system, after cooling, and the temperature gradually increased to about 150C over a period of about 90 minutes. Following the removal of the solvent, 48.6 grams of the product&#39;and 32.5 grams of stearyl alcohol is heated at 90C for 120 minutes. The reaction mixture is dissolved in chloroform and added to a solution of pyridine&#39;N-oxide in chloroform (17 grams pyridine N-oxide in 102 grams chloroform). The reaction mixture is stirred for 60 minutes and on solvent evaporation, a water dispersible product is obtained.  
  In the following examples, kraft pulp of 450 ml freeness, and 0.30 consistancy, is admixed with a 5 percent aqueous dispersion of a resin prepared in accordance with the procedure of Example 1, and the concentration is adjusted to the indicated level. After stirring for 30 minutes, hand sheets are prepared and cured for 30 minutes, at 105C and conditioned overnight at about 25C and 50 percent relative humidity. The results are set forth in the following table.  
 and c are numbers having a value of from zero to 3; x is a number having a value of from 1 to 10 and y is a number having a value of from 0.8 to 4.  
  TREAT- MENT EXAMPLE LEVEL Add on pH TENSILE STRENGTH (Kg/mm) Dry Wet Control 0 O 8.0 7.0 0.3 4 l 1.0 0.2 8.0 5.7 0.6 16 2 2.5 0.6 7.4 5.0 1.0 20 3 2.5 0.7 7.4 4.0 1.2 4 5.0 1.4 7.4 3.8 [.6 42 5 5.0 1.5 7.3 4.6 1.2 30  
  The samples of l-5, when subjected to a standard water-methanol water repellency test, are unwetted by 10, 40, 60, 60 and 80 percent methanol-water solutions, respectively.  
 What is claimed is:  
  l. A process for rendering fibrous materials wetstrengthened and water repellent which comprises treating said fibrous material with a wet-strengthening and 0.1 to 10 percent of water repelling amount of an aqueous dispersion comprising water and a resinous composition of the formula CH O wherein R, R and R are alkyl or aryl organic radicals 45 addon is from 0.2 to 1.5 percent by weight.  
 having from 1 to 12 carbon atoms; R, is an alkyl radical having from 5 to 24 carbon atoms; X is halogen; a, b  
 8. The paper produced by the process as defined by claim 7.