US2794737A - Paper sized with a condensation product of a fatty amine and hexahydro-1, 3, 5-triacrylyl-s-triazine - Google Patents

Description

United States Patent Ofiice 2,794,737 Patented June 4-, 1957 Lennart A. Lundberg and Walter F. Reynolds, Jr., Stamford, Conn., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application June 10, B54, Serial No. 435,917

13 Claims. (Cl. 923) The present invention relates to cellulosic webs, including paper, sized by a content of a condensation product of about 1 to 2 mols of a long chain alkylamine with 1 mol of hexahydro-1,3,5-triacrylyl-s-triazine, and processes for the manufacture of such webs. The invention includes webs sized by a content of such material in at least partially polymerized form.

The present invention is chiefly based upon the dis covery that the condensation products of 1 or 2 mols of a long chain saturated fatty amine with hexahydro-l,3,5- triacrylyl-s-triazine, in the form of their water-soluble salts, are valuable sizing agents which are strongly cationic and substantive to cellulosic fibers dispersed in aqueous medium, and that these materials act as sizing agents which greatly increase the water-resistance of the fibers having a content of the same when formed into paper, etc. It has been found that certain of these compounds perform the additional function of wet strength agents.

We have still further found that the condensation products referred to may be partially polymerized while in aqueous dispersion, and that when so polymerized they yield superior results when employed in the manner described.

The preferred sized paper of the present invention have i the following characteristics.

1. They have good resistance to penetration by water and excellent resistance to penetration by ink and by aqueous sodium hydroxide and lactic acid solutions.

2. They have very nearly the same dry strength as comparable paper containing none of the sizing material.

3. They have very substantial wet strength, and this strength is increased by contact with hot alkali solutions.

4. These properties are not significantly affected by the pH at which the cellulosic fibers are sheeted. The paper may thus contain without substantial detriment alkaline fillers such as calcium carbonate, or be used as material for the packaging of alkaline material such as cement or plaster.

The cellulosic webs of the present invention, broadly, are made by a process which includes the steps of contacting cellulosic fibers with an aqueous dispersion of the sizing materials referred to in either monomeric or partially prepolymerized form, depositing an effective amount on the fibers, and heating the fibers to dry the same and develop the sizing properties of the sizing agent thereon. During this heating, polymerization may take place depending on the presence or absence of a catalyst.

Sized webs of the present invention may be prepared by the tub-sizing method in which a preformed cellulosic web is immersed in or sprayed or padded with a dilute (1%-5 aqueous dispersion ofv the sizing material, after which the web is dried by heating.

The webs may be more conveniently prepared by the beater addition method, this method taking advantage of the strongly cationic, cellulose-substantive characteristics of the sizing material. According to this method, a dilute dispersion of the size is added to an aqueous cellulosic fiber suspension, which may have a pH between 4 and 9.

Adsorption is rapid, a sufliciently eifective amount usually being adsorbed within about 1 minute and often within a few seconds. The fibers are then sheeted to form paper or other web. Development of the water-repellence and wet strengthening properties of the size substantially takes place when the web is heated for about one-half minute at 260 F. or 3-10 minutes at about 200 F.

Alkaline filled paper may be manufactured by adding calcium carbonate or other alkaline filler after addition of the resin to the aqueous fibrous suspension.

In some instances as little as 0.1% of the size material, based on the dry weight of the fibers, has imparted a noticeable amount of water-resistance, and the addition of this amount is therefore within the scope of the present invention. Much better results are obtained when about 0.5% is added, this amount being considered about the minimum needed for useful results in the absence of other sizing agents. Best Water-resistance per increment of sizing material added is obtained in the range of about to 2% and larger amounts produce only a minor increase in wet strength. However, up to about 4%5% may be added with continued and substantial increases in wet strength.

The sizing materials are conveniently prepared by a process which commences with heating between about 1 and 2 mols of a long chain saturated fatty amine with hexahydro-1,3,5-triacrylyl-s-triazine, a method for the preparation of which is disclosed in U. S. Patent No. 2,559,835.

The condensation products containing 1 mol of fatty amine are preferred, since this group of compounds usually gives best sizing results and wet and dry strength.

Preferably, the amines referred to are long chain saturated fatty amines, that is, alkylamines containing 16-22 carbon atoms, the water repellence afforded decreasing rapidly when chains of shorter length are employed, and the dispersibility of the addition products, even in the form of their salts, being unduly difficult in the case of chains of greater length. In practice, we prefer to use o'ctadecylamine, this material being readily available while yielding a product which disperses readily while providing satisfactory water-resistance. Unsaturated fatty amines are tolerated well in small amounts and thus there may be used the commercial, not quite completely hydrogenated amines derived from naturally-occurring fatty acids containing up to about 10% of unsaturated material.

The condensation products, after removal of any sol vent present, are normally waxy solids, and are conveniently made into a size by grinding to a powder and slowly pouringthe powder into a volume of rapidly agitated hot water containing suflicient of a lower watersoluble acid to form a fluid dispersion or suspension containing up to about 15% of the product as an amine salt thereof, beyond which concentration the dispersion is very viscous. It is preferred that less of the condensation product be added so that the dispersion is quite fluid. Ordinarily, about 1 mol equivalent of acid is employed per mol of combined long chain amine, but often a lesser amount has proved satisfactory while an excess does no harm. As acids, chloroacetic (mono-, di-, or tri-), formic, hydrochloric, glycolic, and propionic may be used. Acetic acid is preferred, this acid being non-toxic, readily available, and appearing to yield salts of the lowest softening point.

The dispersions thus formed, when diluted, exhibit the opalescent bluish haze indicative of the presence of colloidal material therein, and may be employed without further treatment in the manufacture of paper. More advantageously, however, the dispersions are subjected to a'preliminary polymerization. This is most conveniently done by treating the dispersions, hot or cold, with a small amount of any of the organic catalysts heretofore known to promote vinyl polymerization. t-Butyl hydroperoxide, peracetic acid, methyl ethyl ketone peroxide, performic acid, and the like are suitable, but because of its freedom from color and lack of toxicity, we prefer to use hydrogen peroxide which yields entirely satisfactory results. Catalysts of the inorganic salt type are less convenient since these acts quite rapidly and tend to cause the dispersions to flocculate or gel in a comparatively short time. Completion of the action of the catalyst and therefore of the polymerization occurs when the dispersions cease increasing in viscosity, this, in the case of hydrogen peroxide, usually requiring from about 30 minutes to 24 hours depending on the temperature, concentration of the dis persion, and the amount of catalyst added. It is unnecessary to wait for termination of the pre-polymerization reaction, excellent results having been obtained when the material has reacted to a roughly estimated of completion. The dispersions are best added to the cellulosic fiber suspension before they have entered the gel stage or have flocculated, depending on the effect of the particular catalyst used.

The effect of this pre-polymerization is to increase the size and cationic strength of the particles, as a result of which paper and other cellulosic products are obtained having greater wet and dry strength without increase in the temperature or duration of the curing step.

A particular advantage associated with hydrogen peroxide as catalyst is that only a very small amount is efiective and the use of a very large amount is not accompanied by any serious detriment. Moreover, it acts with sutficient rapidity at room temperature. Thus, as little as 5% based on the weight of solids in the dispersion has been very successfully, and the addition of 20% has given substantially identical results, 24 hours of standing being allowed in each instance so as to permit the catalytic action of the hydrogen peroxide to become substantially fully evident. Only a negligible decrease in dry and wet strength and water-resistance was observed in the paperproduced when 20% of hydrogen peroxide was added based on the weight of size solids with a standing time of five days. Moreover, in one experiment handsheets were made from the dispersion of Example 1 without peroxide addition and from dispersion of the same material containing 20% of hydrogen peroxide on the weight of the size therein, handsheets being made five minutes, one hour, three hours, six hours, and 24 hours after addition of the hydrogen peroxide. The sheets were tested for their dry and wet tensile strength and water-resistance by the Currier test, and ink-resistance by the BKY test, and the sheets were formed at pH values of 5.0 and 9.0. With hydrogen peroxide at room temperature, the properties of the material as sizing agent were substantially completely developed at the end of one hour of standing or perhaps somewhat earlier. Thus, it appears that hydrogen peroxide is incapable of causing overpolyrnerization under normal conditions. With other and more active catalysts the dispersions should be used before evidence of flocculation or gelation appears.

The invention will be further illustrated by the examples which follow. These examples are preferred embodiments of the invention and are not to be construed as limitations.

Example 1 was obtained which was crushed and oven-dried under vacuum at 50-55 C. for six hours. The product was 1,3 diacrylyl hexahydro-S-octadecylaminopropionybstriazine or a low molecular weight homopolymer thereof.

Example 2 The procedure of Example 1 was repeated using 128 g. (0.516 mol) of hexahydro-1,3,S-triacrylyl-s-triazine, 291 g. of octadecylamine (1.03 mols), and 800 cc. of ethylene dichloride. The product contained 2 mols of combined octadecylamine per mol of the triazine taken. The product was hexahydro 1 acrylyl-3,5-(octadecylaminopropionyl)-s-triazine or a low molecular weight homopolymer thereof.

Example 3 A series of papers was prepared as follows to illustrate the effect of varying the number of mols of combined octadecylamine, the effect of partial pre-polymerization, the amount of condensation product added, and the pH of the fibrous suspension.

Sizing dispersions were made by grinding the products of Examples 1 and 2, respectively containing 1 and 2 mols of combined octadecylamine, and slowly pouring the powders into water at C. containing 1 mol of acetic acid per mol of combined octadecylamine present. Two viscous dispersions were obtained, each of which contained 2.25% solids. The dispersions were divided into portions and these were used either without modifi cation or after pro-polymerization with hydrogen peroxide as shown in the table below. In the case of the dispersion formed from the product of Example 1, pre-poly' merization was effected by allowing the peroxide-treated dispersion to stand for 2 hours at roomtemperature. In the case of the dispersion formed from the product of Example 2, 3 hours of standing was allowed.

In each instance the dispersions were stirred into 0.6% consistency bleached 60% su1fite-40% soda blended pulp suspensions which had been beaten to a Green freeness of 475ml. After addition of the dispersion, the pH of the suspensions was adjusted to the values shown in the table by the use of. hydrochloric acid or sodium hydroxide as necessary, gently stirred for five minutes, and sheeted on a Nash handsheet machine. The sheets were dried for one minute at 240 F. without blotter, conditioned for 24 hours at 72 F. and 50% relative humidity, and tested as shown in the table below.

Tensile Percent Percent Strength, BKY No. 11 0 Size pH of Basis Lb./in. Currier Ink Added Added 1 Stock 3 Wt. Sec. Sec. To Size 1 Dry Wet;

1---- Control Nil 46.0 17.8 I 0. 2 3 3 Product of Example 1 2. Nil 5.0 4. 5 46. 0 9. 3 1. 4 18 600 3. Nil 5. 0 9.0 46. 6 8. 7 2. 8 56 600 4--.. 10 5.0 4. 5 46.0 11. 9 2.7 54 600 5-. 10 6. 0 9. 0 46. 2 12. 4 2. 9 55 (600 6- 10 2. 5 4. 5 48. 1 13. 9 3. 8 60 (600 10 2. 5 9. 0 47. 3 14. 6 2. 9 48 600 8...- 10 1. 25 4. 5 47. 3 15. 1 2. 3 50 600 9---. 10 1. 25 9. 0 47. 0 15. 7 1. 6 23 Product of Example 2 10... N11 5. 0 4. 5 45. 2 6. 2 1. 4 54 600 Nil 5. 0 9. 0 44. 9 5. 4 1. 8 56 600 12. 10 5. 0 4. 5 45. 2 5. 9 1. 2 51 600 13... 10 5.0 V 4. 5 44. 9 5. 1 1. 7 61 600 Example 4 The manufacture of sized paper by the tub-sizing process using a sizing material prepared from the product of Example 1, showing the efiect of the peroxide treatment is illustrated by the following.

A set of sulfite-soda handsheets having a basis weight of 48.0 lbs. and containing no added material whatever were impregnated with aqueous dispersions at various dilutions of the product of Example 1 at pH 4.5, prepared according to Example 2 without the use, of hydrogen peroxide. The sheets were squeezed to remove excess liquid and were estimated to contain by weight of sizing solids. One of the sheets was set apart as primary control and air-dried without further treatment. A second sheet was impregnated with plain water at pH 4.5 as secondary control and dried at 240 F. for 1 minute on a laboratory drum dryer. The three remaining sheets were air-dried and impregnated with aqueous hydrogen peroxide to absorb hydrogen peroxide in amounts shown in the table below. The three test sheets were dried in the same manner as sheet No. 2; the size thus being cured in the presence of hydrogen peroxide. The dry tensile strength and water-resistance (Currier) of the sheets were then determined with the following results.

The table shows that while good sizing was obtained (No. 2) without use of hydrogen peroxide, much better results were obtained when the size was cured in the presence of hydrogen peroxide.

Example 5 The following papers were made to illustrate the extraordinary lactic acid-resistance imparted by the size. The sizing material employed was prepared by adding 20% of hydrogen peroxide (as a 30% aqueous solution) to a 4.70% aqueous dispersion of the product of Example 1 made by the use of acetic acid, and allowing the mixture to stand for 3 hours at room temperature. The suspension employed w!as bleached northern kraft pulp beaten to a Green freeness of 485 ml. and diluted to 0.6% consistency. After addition of the size, the suspensions were adjusted to pH 5 or 9 as shown in the table below, and stirred for five minutes. The sheets were made according to the method of Example 3, except that they were dried for 3 minutes at 240 F. because of their greater thickness. The water-absorption test was made by the total immersion method and the lactic acid test by applying a 20% aqueous solution of lactic acid to one side of the sheet and noting the time required for the solution to pass through at 100 F.

1 For explanation, see previous table.

Similar untreated paper absorbs 100% or more of its weight of water, and is instantaneously saturated by lactic acid.

Example 6 The following illustrates the resistance of sized paper of the present invention to boiling water, acid, and

Sized handsheets were prepared at a basis weight of about 48 lbs. from bleached northern kraft pulp employing the hydrogen peroxide treated acetate dispersion of Example 5. The sheets were dried for one minute at 240 F. and strips cut from each. The strips were aged at room temperature and their dry tensile strength values determined. In addition, one set of strips was boiled in 5% sodium carbonate solution, and another set in 2% sulfuric acid for 10 minutes each. The wet tensile strength of these strips was then determined. Results were as follows:

Tensile Wet Tensile After- Percent Basis WtJ Size Added I Stock pH Dry W6C N 800; H180 Boll Boil Nil 44. 7

encore comma 1 For footnotes, see previous table.

The data show that the alkali boil tended to increase the wetrstrength of the paper, while appreciable wet strength remained after the acid boil.

What we claim is:

1. A cellulose web comprising water-laid cellulose fibers sized by a content of from 0.1% to 5% of their dry weight of a condensation product of about 1 to 2 mols of a long chain saturated fatty amine wherein the chain contains 16-22 carbon atoms with 1 mol of hexahydrol,3,S-triacrylyl-s-triazine.

2. A web according to claim 1, wherein the condensation product is present in at least partially polymerized form.

3. A cellulosic web comprising water-laid cellulose fibers sized by a content of from 0.1% to 5% of their weight of a condensation product of about 1 mol of a long chain saturated fatty amine wherein the chain contains 16-22 carbon atoms with 1 mol of hexahydro- 1,3,S-triacrylyl-s-triazine.

4. A web according to claim 1, wherein the alkyl amine is octadecyia mine.

5. A web according to claim 1 containing from about 2% to 30% by weight of calcium carbonate filler.

6. A process for manufacturing sized paper which comprises contacting cellulosic fibers with a dilute aqueous dispersion of a salt of a condensation product of about 1 to 2 mols of a long chain saturated fatty amine wherein the chain contains 16-22 carbon atoms with 1 mol of hexahydro-1,3,S-triacrylyl-s-triazine, thereby depositing between about 0.1% to 5% of said product on said fibers based on the dry weight thereof, and heating the fibers at about l90-260 F. for one-half to ten min utes to dry the same and to develop the water-resistance properties of the condensation product thereon.

7. A process according to claim 6 wherein the dispersion contains the condensation product in partially polymerized form.

8. A process for manufacturing sized paper which comprises forming an aqueous dispersion of cellulosic fibers, adding thereto an aqueous dispersion containing from about 0.1% to 5%, based on the dry weight of the fibers, of a salt of a condensation product of between about 1 and 2 mols of a long chain saturated fatty amine wherein the chain contains 16-22 carbon atoms with 1 mol of hexahydro-1,3,5-triacrylyl-s-triazine, thereby ad sorbing said condensation product on said fibers, sheeting the fibers to form a cell-ulosic web, and heating the web at about 260 F. for about one-half to ten,

minutes to develop the sizing properties of the condensation-product thereon.

9. A process. according to claim 8 wherein the condensation product is addedin partially polymerized form.

10. A process according to claim 8 wherein the libers are sheeted at a pH above 7.

11; A-process according to claim .8 wherein from about 2% to 30% of-calcium carbonate. filler is added to the suspension subsequent to addition of the condensation product.-

12. A process according to claim 8 wherein the condensation product is the addition product of about 1 mol of a long chain saturated fatty alkyl amine wherein the chain contains 16-22 carbon atoms with 1 mol of hexahydro-1,3,5-triacrylyl-s-triazine.

13.- A process according to claim 8 wherein the alkyl amine is octadecylamine.

References Cited in the file of this patent UNrrEp 4 STATES PATENTS Britt July 27, Schur Jan. 4, Sherman Nov. 15, Harrison et al. Apr. 11, Zerner et a1. July 10, Zerneret al. July 10, Daniel et a1. June 24, Zerner, et a1. Sept. 8, Daniel e t a1. Oct. 27, Lindqui st Feb. 11, Reynolds. y 6, Reynolds, Nov. 16,

OTHER REFERENCES MacDonald Paper Trade J.; April 11, 1929; page 54.

Claims (1)

1. A CELLULOSE WEB COMPRISING WATER-LAID CELLULOSE FIBERS SIZED BY A CONTENT OF FROM 0.1% TO 5% OF THEIR DRY WEIGHT OF A CONDENSATION PRODUCT OF ABOUT 1 TO 2 MOLS OF A LONG CHAIN SATURATED FATTY AMINE WHEREIN THE CHAIN CONTAINS 16-22 CARBON ATOMS WITH 1 MOL OF HEXAHYDRO1,3,5-TRIACRYLYL-S-TRIAZINE.