Process for fiber treatment
United States Patent [1 1 Pattison Apr. 29, 1975 PROCESS FOR FIBER TREATMENT [75] Inventor: Victor A. Pattison, Tonawanda,  
 [73] Assignee: Hooker Chemicals &amp; Plastics Corp., Niagara Falls, N.Y.  
 [22] Filed: Jan. 12, 1973 [21] App]. No.: 323,179  
 [52] U.S. Cl. l62/l67; 260/295 AM; 260/295 CA [5 I] Int. Cl D2lh 3/12 [58] Field of Search l62/l64, I58, I67; 260/295 AM(), 295 E, 295 CA; 8/189, 182.  
 [56] Relerences Cited UNITED STATES PATENTS 8/l950 Baird et al 260/295 AM 8/1950 Baird et al 260/295 AM Primary ExaminerRobert L. Lindsay, .Ir.  
 Assixranl Examiner-William F. Smith Attorney, Agent, or FirmPeter F. Casella; John M. Petruncio [57] ABSTRACT Compositions of the formula in aqueous dispersion are used to improve we! strength characteristics of fibrous materials, particularly paper and paper products.  
 7 Claims, No Drawings 1 PROCESS FOR FIBER TREATMENT This invention relates to the treatment of fibrous materials. More particularly. this invention relates to the improvement of wet strength of paper and paper prod ucts.  
  For many years. no commercially available \vet strength resins were available which would function effectively at a pH much about 5.5. i.e.. on the acid side. As a consequence, many grades of paper made on the alkaline side for various reasons. including strength. softness. use of alkaline fillers and the like. could not be effectively wet-strengthened.  
  It is the object of the present invention to provide paper and paper products having improved wet strength.  
  It is the object of the present invention to provide a novel process for imparting wet strength to paper and to paper products.  
  These and other objects and advantages of the present invention will become apparent from a reading of the description which follows and from the appended claims.  
  it has been found that paper and paper products can be effectively wet-strengthened. by the treatment of such materials. in acid or alkaline medium. with an aqueous solution of a treating material of the formula s ug! l l \2 wherein R and R, are organic radicals. substituted or unsubstituted. generally having from 1 to about 12 carbon atoms; a and I) are numbers having a value of from zero to 3; X is halogen; and x is a number having a value of from about 1 to about I0.  
  The fibrous materials which may be treated according to the process of the present invention include such as textile and paper fibers. or textile and paper products. the process being 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 treating materials hereinbefore specified as aqueous solutions. and at a pH ranging from the acid side. i.e.. lower than 7.0. to an alkaline pH. on the order of 7.5 or higher. Generally. the solutions contain from about 0.l to about percent by weight of treating material. preferably from about i to about 5 percent by weight of the treating material.  
  The paper pulp or paper products may be treated with the aqueous treating solutions in any convenient manner. Generally. where pulp is to be treated. the  
 treating solution is added to the pulp slurry. and the mixture stirred to effect the pulp treatment.  
  Desirably. the treatment is effected such that the paper has an add-on of treating material of from about 0.1 to about 5 percent by weight. based on the dry weight of the paper treated. Higher treating material add-ons may be obtained. if desired. However. treatment to effect add-on within the range specified is generally sufficient to provide suitable wet streangth.  
  The addition of the aqueous treating solution may be conveniently effected at ambient temperatures. i.e.. 25C. Following the contacting of the paper or paper product with the aqueous treating solution, generally a period of about 30 minutes being sufficient to achieve the desired addon. the paper is subjected to excess water removal dried and cured. generally at a temperature of about C for a period of about 30 to about 60 minutes. In the instance where pulp is treated. the pulp is sheeted out. e.g.. as handsheets. excess water removed. and the sheets dried and cured.  
  The treating materials may have molecular weight on the order of from about 250 to about 2.500. or higher.  
  The treating materials used in the present process may be prepared by:  
  a. reacting N-methyl aniline. or a substituted N- methyl aniline. or mixtures of suitable N-methyl anilines with formaldehyde in a condensation reaction;  
  b. the product obtained from step (a) is reacted with a carbonic dihalide;  
  c. the product obtained from step (b) is reacted with a suitable pyridine or ring-substituted pyridine or suitable mixture thereof.  
  In the formula hereinbefore set forth. suitable R and R, radicals include methyl. ethyl. propyl. butyl. hexyl. heptyl. octyl. decyl. phenyl. naphthyl. functional derivatives of such radicals and the like.  
  Suitable carbonic dihalides include phosgene. carbonic dibromide and the like. Preferably. the carbonic dihalide is phosgene.  
  Suitable N-methyl anilines include. among others. N- methyl aniline; 3.5-dimethyl N-methyl aniline; 4- phenyl N-methyl aniline; 3-hexyl N-methyl aniline; 4- hexyl N-methyl aniline; 4-anphthyl N-methyl aniline; 4-(4-chloro-phenyl) -N-methyl aniline. and the like. as well as suitable mitures thereof. Unsubstituted N- methyl aniline is most preferred.  
  Suitable pyridines include 3.5-dipropyl pyridine; 3- methyl pyridine; pyridine. as well as suitable mixtures thereof. The most preferred is unsubstituted pyridine.  
  The formaldehyde used to prepare the resins may be obtained from auch sources as aqueous solutions of formaldehyde. trioxane. paraformaldehyde. or the like.  
  The reaction of the N-methyl aniline compound and formaldehyde is conducted by adding the formaldehyde on a continuous basis to the aniline reactants in an acid medium. the formaldehyde added in such amounts as to effect condensation with the aniline present. Following the addition of the formaldehyde. the reaction is made alkaline by the addition thereto of a suitable alkaline agent. such as aqueous sodium hydroxide. a solid product resulting. The liquid phase is removed and the reaction product 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 of the reaction mixture during the condensation is generally maintained at from about [00 to about C. preferably from about [30 to about 160C. with the condensation generally essentially completed within a period of from about 60 to about 90 minutes.  
  The reaction product is then reacted with a selected carbonic dihalide. preferably phosgene. by adding a suitable organic solvent. heating to a temperature suffcient to remove any water present. cooling to less than about 35C. and adding the carbonic dihalide continuously. in about stoichiometric amounts. to convert the N-methyl amino groups to carbamoyl halide groups and the amino groups to isocyanate groups. Heat is applied to move the temperature gradually up to about l50C. hydrochloric acid being evolved. The temperature is generally moved through a range of from about 35 to about [50C over a period of about 90 minutes. The solvent is removed by distillation. generally at about lC under reduced pressures. Generally. the reaction is completed within a period of from about 90 to about l20 minutes.  
  Suitable solvents include the halogenated hydrocarbons such as chlorobenzene. dichlorobenzene and the like.  
  The reaction product from step (b) is then reacted with the selected pyridine compound by adding the pyridine compound in about stoichiometric amounts. based on the carbamoyl halide groups present. stirring and allowing the reaction mixture to stand for about 2-8 hours. at ambient temperatures. The reaction. however. may be conducted at elevated temperatures. on the order of about 90C.  
 EXAMPLE l N-methyl aniline is condensed with formaldehyde at a pH of about l and at a tmeperature of about lC. The reaction mixture is added to dichlorobenzene and heated to remove water present. Phosgene is added to the reaction system. after cooling to below about C. and the temperature gradually increased to about lC over a period ofabout minutes. Following removal of the solvent. a mixture of l8.l grams of the product and pyridine 7.9 grams are admixed and heated at about 90C for about [5 minutes. The reaction system is sealed and allowed to stand and cool overnight. The product is a dark friable wax soluble in water.  
  ln the following examples. untreated kraft pulp is admixed with varying concentrations of aqueous solutions of a material prepared in accordance with the procedure of Example 1. After stirring for about 30 minutes. hard sheets are prepared and cured at about l05C for about 30 minutes. and conditioned overnight at about 25C and 50 percent relative humidity. The results are set forth in the following table.  
  TENSILE STRENGTH EXAMPLE tKg/l5mml EXAMPLE LEvEL pH Dry Wet z ADDON Control a 7.6 a 7.0 0,3 4 I&#34; 0.5 7.6 0.1l 8.0 l .0 l3 2&#39;- m 11. 0.52 8.7 1.6 l4 .1&#34; 2.5 7.4 1.76 so 20 2s 4&#34; so 72 3.1 as 3.2 37 5&#34; us 7.6 an; as 1.2 14 e 1.0 7.6 use 8.6 H1 17 1&#34; 2.5 7.4 2.0 8.9 3.0 34 a&#34; su 7.2 4.3 1.7 2.9 38  
 What is claimed is:  
  l. A process for rendering fibrous materials wetstrengthened which comprises treating saiad fibrous material with a wet strengthening amount of a 0.1 to 10 percent of aqueous solution comprising water and a treating material of the formula wherein R and R are alkyl or aryl organic radicals having from l to [2 carbon atoms; a and b are numbers having a value of from zero to 3; X is halogen; and .v is a number having a value of from 1 to about 10.  
  2. A process as defined by claim 1 wherein the treating material is present in the solution in an amount of from 1 to 5 percent.  
  3. A process as defined by claim 2 wherein u and b are each zero.  
 4. A process as defined by claim 3 wherein X is chlorme.  
  5. A process as defined by claim 4 wherein the fibrous material treated is paper pulp.  
  6. A process as defined by claim 5 wherein the resin add-on is from about 0.1 to about 5.0 percent by weight.  
  7. Paper produced by the process as defined by claim 6.