Patent Publication Number: US-3880708-A

Title: Process for fiber treatment

Description:
United States Patent n 1 Pattison Apr. 29, 1975 1 i PROCESS FOR FIBER TREATMENT [75] Inventor: Victor A. Pattison, Tonawanda.  
 [73] Assignee: Hooker Chemicals &amp; Plastics C0rp., Niagara Falls, N.Y.  
 [22] Filed: Jan. 12,1973  
 [21] Appl. No.: 323,020  
 [56] References Cited UNITED STATES PATENTS 2.518266 3/1950 Baird et al 260/295 AM 2.518267 8/1950 Baird et al 260/295 AM Primary Examiner-Robert L. Lindsay, .lr.  
 ANS/SIG!!! Examiner-William F. Smith Attorney. Agent, or FirmPeter F. Casella; John M. Petruncio [57] ABSTRACT Compositions of the formula 1 a 1 ll in aqueous dispersion are used to improve wet strength and water repellency characteristics of fi brous materials, particularly paper and paper products.  
 8 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 and water repellency properties of paper and paper products.  
  For many years. no commercially available wet 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.  
  Additionally. in providing papers of wet strength and additional properties. such as water repellency. it has generally been found that paper must be treated with specific compositions to impart specific properties. e.g.. separate conditioning agents for wet strengthening and for water repellency.  
  It is an object of the present invention to provide paper and paper products having improved wet strength and water repellency properties.  
 It is another object of the present invention to provide a process for imparting wet strength and water repellancy properties to paper and to paper products by subjecting such materials to treatment with a single treating agent.  
  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 and water proofed by the treatment of such materials. in acid or alkaline medium. with an aqueous dispersion of a resinous material of the formula C11 a o (m N, a -G-O-R3 e J .........a (HZ l R2 (R1) L b x 2 c.  
 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 resinous materials hereinbefore specified as aqueous dispersions. 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 dispersions contain from about 0. l to about l0 percent by weight of the treating material. preferably from about 1 to about 5 percent by weight of the treating material.  
  The paper pulp or paper product may be treated with the aqueous dispersion in any convenient manner. Generally. where pulp is to be treated. the dispersion 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 0.2 to about 2 percent by weight. based on the dry weight of the paper treated. Higher treating material add-on may be obtained. if desired. However. treatment to effect addon within the range specified is generally sufficient to provide suitable wet strength and water repellency values.  
  The addition of the aqueous dispersion may be conveniently effected at ambient temperatures. i.e.. C. Following the contacting of the paper or paper product with the aqueous treating dispersion. generally a period of about 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 105C for a period of about 30 to about minutes. in the instance where pulp is treated. the pulp is sheeted out. e.g.. as handsheets. excess water removal. and the sheets dried and cured.  
  The treating materials may have molecular weights on the order of from about 500 to about 2.500. or higher. Particularly useful are those resinous treating materials wherein the ratio of .r to y. the values of which have been hereinbefore expressed. is about 3:2.  
 The resin 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 Nmethyl anilines with formaldehyde and a non-N-substituted aniline. or suitable mixtures. in a condensation reaction;  
  b. the resin obtained from step (a) is reacted with a carbonic dihalide;  
  c. the resin obtained from step (b) is reacted with a C5-C aliphatic alcohol; and  
  d. the resin obtained from step (c) is reacted with a suitable pyridine or ring-substituted pyridine or suitable mixtures thereof.  
  In the formula hcreinbefore set forth. suitable R. R, and R radicals include methyl. ethyl. propyl. butyl. hexyl. heptyl. octyl. decyl. phenyl. naphthyl. functional derivatives of such radicals and the like. Exemplary of suitable R radicals are pentyl. heptyl. dodecyl. stearyl. and the like, having from about 5 to about 24 carbon atoms. The preferred R radical is the stearyl radical l m ;n)  
  Suitable carbonic dihalides include phosgene. carbonic dibromide and the like. Preferalby. 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-naphthyl N-methyl aniline; 4-(4-chloro-phenyl)-N-methyl aniline. and the like, as well as suitable mixtures thereof. Unsubstituted N- methyl aniline is most preferred.  
  Suitable non-N-substituted anilines include 3.5- dimethyl aniline; 4-phenyl aniline; 3-hexyl aniline; 3,4,5trimethyl aniline; 4-naphthyl aniline and the like. as well as suitable mixtures thereof.  
  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 prepared the resin may be obtained from such sources as aqueous solutions of formaldehyde. trioxane paraformaldehyde, or the like.  
  The reaction of the alkaline compound. 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 anilines 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 reamining 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 l00 to about 160C. preferably from about 130 to about l60C, 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 sufficient 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 150C over a period of about 90 minutes. The solvent is removed by distillation, generally at about 120C under reduced pressures. Generally the reaction is completed within a period of from about 90 to 120 minutes.  
  Suitable solvents include the halogenated hydrocarbons such as chlorobenzene, dichlorobenzene and the like.  
  The product of step (a) is then reacted with the selected fatty alcohol. or suitable mixtures thereof, by adding the alcohol, with stirring, to the resin in amounts sufficient to convert essentially all of the isocyanate groups to carbamoyl ester groups, generally at a temperature of about C. the reaction being essentially completed within a period of about 30 minutes. The fatty alcohols suitable for use are those having from about 5 to about 24 carbon atoms, i.e., pentanol to tetra-cosanol.  
  The reaction product from step (c) 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 28 hours, at ambient temperatures. The reaction, however, may be conducted at elevated temperatures, on the order of about 90C.  
 EXAMPLE I N-methyl aniline (257 parts by weight) is condensed with formaldehyde and aniline 149 parts by weight) at a pH of about I and at a temperature of about C. The reaction mixture is added to dichlorobenzene and heated to remove water present. Phosgene is added to the reaction system, after coolin to below about 35C. and the temperature gradually increased to about [50C over a period of about 90 minutes. Following removal of the solvent, a mixture of l 5 grams ofthe product and 43 grams of stearyl alcohol are heated at about 90C for a period of about 30 minutes. Pyridine (20 grams) is added to the hot reaction product and stirred for about 15 minutes until homogeneous. The reaction system is sealed and allowed to stand an cool overnight. The product is a friable wax easily dispersed in water, a 5 percent weight.  
  In the following examples, untreated kraft pulp is admixed with varying concentrations of aqueous dispersion of a resin prepared in accordance with the procedure of Example l. After stirring for about 30 minutes. hand 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 TREAT- STRENGTH MENT (Kg/15mm) EXAMPLE LEVEL I; ADDON Dr Wet &#39;2 Control 0 0 8.4 0,! l  
 l (Llll (M4 7.9 0.5 6 Z (1.25 0.36 7.7 (H1 8 3 (1.5 0.70 7 l l.ll l4 wherein R. R and R are alkyl or aryl organic radicals. 4. A process as defined by claim 3 wherein X is chlohaving from I to 12 carbon atoms; R;, is an alkyl radical rine. having from to 24 Carbon atoms; X is halogen; b 5. A process as defined by claim 4 wherein the ratio and c are numbers having a value of from zero to 3; .r 70 of ,t to y is about 3:2. is a number having a value of from I to and is a 6. A process as defined by claim 5 wherein the finumber from 0.8 to 4. brous material treated is paper pulp.  
  2. A process as defined by claim 1 wherein the resin- 7. A process as defined by claim 6 wherein the resin ous material is present in the aqueous dispersion in an addon is from 0.2 to 2 percent by weight. amount of from 1 to 5 percent. H 8. Paper produced by the process as defined by claim 3. A process as defined by claim 2 wherein a. b. and 7. c are each zero.