US2684300A

US2684300A - Sizing paper and product

Info

Publication number: US2684300A
Application number: US26928A
Authority: US
Inventors: William S Wilson; Albert H Bump
Original assignee: Monsanto Chemicals Ltd
Current assignee: Monsanto Chemicals Ltd; Monsanto Chemical Co
Priority date: 1948-05-13
Filing date: 1948-05-13
Publication date: 1954-07-20
Anticipated expiration: 1971-07-20

Description

Patented July 20, 1954 UNITED STATES A'E'ENT QFFICE SIZING PAPER AND PRODUCT poration of Delaware No Drawing. Application May 13, 1948, Serial No. 26,928

6 Claims.

This invention relates to methods, and particularly to the use of aqueous dispersions capable of markedly increasing the efiiciency of ordinary rosin dispersions in the engine sizing of paper pulp.

It is customary at the present time to engine size paper pulp by mixing with a suspension of the pulp a dilute aqueous dispersion of rosin which has been at least partially neutralized with alkali. The rosin is then precipitated, coagulated and fixed on the pulp by adding to the suspension a small quantity of aluminum sulfate (known as alum in the papermakers art), usually about 1% by weight of the dry pulp. The dispersed rosin may be added in varying amounts, depending upon the results desired, but is usually added in amounts between and 4% based on the weight of the dry pulp being treated.

One of the objects of this invention is to provide a method of improving the sizing efiiciency of ordinary rosin size dispersions such as those described above.

A further object of the invention is to provide a sizing adjunct which, when employed in combination with rosin or other sizing agents in the engine sizing of pulp suspensions, not only provides a considerably higher degree of sizing than an equivalent amount of rosin alone, but also permits equivalent sizing with much lower rosin dosages.

Still further objects and advantages of the invention will appear from the following description and appended claims.

improved sizing The methods of the invention are carried out in general by first adding to the beater a pre determined amount of pulp in the formof a dilute aqueous suspension, after which a dilute aqueous dispersion of rosin which has been at least partially neutralized with caustic alkali,

soda ash or the like, is added in an amount sufficient to supply from to 4% of rosin based on the weight of the dry pulp used. A dilute aqueous dispersion of the reaction product of rosin with an acidic compound containing the -CO-C=C group, which product has also been at least partially neutralized with alkali, is then added, preferably in an amount sufiicient to supply between 20 and 50% of the reaction product based on the weight of the rosin employed. The dispersed mixture of rosin and resinous reaction product contained in the pulp is then fixed to the pulp fibres by adding a small amount of aluminum sulfate to the beater and thoroughly mixing the same with the treated pulp suspenmon.

Although the rosin, resinous reaction product and aluminum sulfate are preferably added to the pulp in the order described above, it is also possible to add the resinous reaction product first, and then the rosin. Moreover, the aluminum sulfate may be added at any stage, and if desired all of the above sizing materials may be added to the pulp at one time.

Suitable acidic compounds containing the CO-C=C group include alpha-beta unsaturated polybasic organic acids or acid anhydrides, such as maleic, fumaric, itaconic and citraconic acids and their anhydrides. Thus, broadly the materials which are adapted to improve the sizing efiiciency of rosin according to this invention include the reaction products of rosin with a compound of acidic character containing the CO--C=C group, such as those referred to above. The most suitable resinous reaction product for the purposes of this invention, however, is the resin prepared from rosin and maleic anhydride. For the sake of simplicity, therefore, reference will be made primarily to the above resin in further describing the details and variables of the invention.

The reaction product per se is generally prepared by heating maleic anhydride with rosin, at 160 to 170 C. for about four hours. The amount of maleic anhydride employed may be varied from about one-quarter to one mol for each mol of rosin, and in many instances some- What lower or higher temperatures than the above may be used. If lower temperatures are used a longer period of heating than four hours may be required, while if higher temperatures are used, the heating period may frequently be reduced.

In charging the beater with the above reaction product, it is necessary to first form an alkaline dispersion of the resin in water to facilitate thorough mixing of the reaction product with the pulp. This is preferably accomplished by first forming a preliminary dispersion of relatively high concentration, after which the concentrated dispersion may be diluted to the desired extent. In general, the rosin-maleic reaction product, caustic soda or other alkali and water are heated and simultaneously stirred in any suitable reaction vessel at temperatures between about 140 and 200 C. The various ma-- terials used may be added in amounts varying from about 50 to of reaction product, 4 to 14% of alkali, and 6 to 46% of water. The charge is finally cooled down to 60 to C., depending upon the amount of reaction product employed, and is then removed, whereupon it cools to a consistency varying from a viscous fluid mass to a hard and brittle solid, which may be ground to a powder. For example, when say 57% of the reaction product, of caustic soda and 38% of water are employed, the resulting dispersion is in the form of a viscous fluid, while when say 80% of the reaction product, 7% of caustic soda and 13% of water are employed, the dispersion in is the form of a hard and brittle solid.

In preparing the secondary or dilute dispersion from the primary dispersion, the latter dispersion is diluted with from 1500 to 4000 parts by weight of water for each 100 parts by weight of the dispersion depending upon the amount of reaction product in the dispersion. The mixing is preferably accomplished with the aid of vigorous stirring and at temperatures varying from to 65 C., depending upon the amount of reaction product present in the primary dispersion. In all instances the resulting product is in the form of a milky dispersion which does not settle to any great extent upon standing.

In using the above milky dispersion as a sizing adjuvant, the beater is first charged with a predetermined amount of pulp, after which the rosin size is added in the form of a dilute aqueous and partially or wholly neutralized dispersion in amounts capable of supplying from about to 4% of rosin based on the weight of the dry pulp used. The dilute dispersion or" rosin-maleic reaction product prepared as described above is then added to the pulp suspension in an amount sufficient to supply from 20 to 50% of the rosinmaleic reaction product based on the weight of the rosin used. After thoroughly beating the mixture the pulp is then ready for the addition of aluminum sulfate or like fixing agent, which may be added in amounts varying from about 1 to 5% based on the dry pulp weight, depending upon the type of paper which it is desired to make. As previously indicated, however, the various materials employed may be added in any desired order, or simultaneously.

A further understanding of the invention will be obtained from the following specific examples of methods of using the sizing adjuvants of the invention.

Example I A paper beater was first charged with 40,000 pounds of a sulfite pulp suspension containing about 5% of dry pulp. To the charge was then added about 30 pounds of rosin in the form of a rosin dispersion which was 70% neutralized and contained 0.29 pound of rosin per gallon of dispersion. The rosin dispersion was beaten into the pulp for about one-half hour, after which an alkaline dispersion of rosin-maleic anhydride reaction product, prepared by reacting rosin with maleic anhydride, partially neutralizing the reaction product and dispersing the neutralized product in suiiicient water to produce a dispersion containing 0.29 pound of reaction product per gallon, was added in an amount sufiicient to provide about 6 pounds of the reaction product. The resulting mixture was beaten for about one-half hour, after which about 5% of aluminum sulfate based on the weight of the dry pulp was added. After a further half hour of beating, the stock was made into paper, which upon being tested by the standard ink penetration test showed 28 minutes sizing. The same stock sized with 62 pounds of rosin in the form of a 70% neutralized rosin dispersion, but without the addition of the rosin-maleic anhydride reaction product, showed 26 minutes sizing. Thus, it was possible to obtain better sizing by using rosinmaieic anhydride reaction product in conjunction with the rosin, even though more than twice as much rosin was used in the absence or" the reaction product.

The extent to which a given sheet of paper is sized is generally expressed in units of time, as for example, the number of seconds or minutes required for a given liquid, such as water, ink or the like, to penetrate the sheet to a predetermined degree. The liquid used, the end point taken, and the method of determining the arrival of the end point vary, and as a result the numerical values obtained by diiierent observers vary quite widely. It is noteworthy however that the comparative values for different kinds or samples of paper are very nearly the same, regardless of the test method employed.

Example II A small paper beater was charged with 132 grams of an alpha pulp suspension containing about 1.7% of dry pulp. To the charge was then added about 2 grams of rosin, or 1.5% based on the weight of the dry pulp, in the form of a rosin dispersion which was 70% neutralized and contained 10 grams of rosin per liter of dispersion. The rosin dispersion was beaten into the plup for about 15 minutes, after which an alkaline dispersion of rosin-maleic anhydride reaction product was added in an amount sufficient to provide about 0.4 gram of the reaction product or 20% based on the weight of the rosin used. The resulting mixture was beaten for about 15 minutes, after which about 1% of aluminum sulfate based on the weight of the dry pulp was added. After another 15 minutes of beating, the stock was made into paper, which upon being tested by the standard ink penetration test showed seconds sizing. The same stock sized with 2 grams of rosin in the form of a 70% neutralized rosin dispersion, but without the addition of the rosin-maleic anhydrid reaction product, showed only 29 seconds sizing.

Example III One hundred and thirty-two grams of an alpha pulp suspension containing about 1.7% of drr, pulp were treated in the manner described in Example II, but using 1 gram of rosin, or 0.75% based on the weight of the dry pulp, and 0.2 gram of the rosin-maleic anhydrid-e reaction product, or 20% of the weight of the resin used. .After making paper of the resulting stock, the paper was tested by the standard ink penetration test and showed 61 seconds sizing. The same stock sized with 1 gram of rosin in the form of a 70% neutralized rosin dispersion, but without the addition of the rosin-maleic anhydride reaction product, showed only 5 seconds sizing.

Example IV To 1500 cc. of a suspension of bleached Gatineau sulfite pulp in water containing 30 grams (2%) of dry pulp were added with agitation 0.2 gram of rosin in the form of an alkaline dispersion in water, which was 70% neutralized and contained 30 grams of rosin per liter of dispersion, and 0.1 gram of rosin-maleic anhydride reaction product in the form of an alkaline dispersion in water which was 50 neutralized and contained 30 grams of the reaction product per liter of dispersion. The resulting mixture was agitated for about 15 minutes, after which about 3.5% of aluminum sulfate on the weight of the dry pulp was added. After another 15 minutes of agitation, the stock was made into paper, which upon being tested by the standard ink penetration test showed 320 seconds sizing. On sizing the same stock. in the same manner as described above, but applying 0.3 gram of resin in the form of a 70% neutralized dispersion instead of the combination of rosin and rosin-maleic anhydride reaction product, and on testing the paper prepared therefrom by the ink penetration method, only 122 seconds sizing was obtained.

Example V A suspension of bleached Gatineau sulfite pulp was prepared and sized in the manner described in Example IV, but using sufficient of the alkaline dispersions to provide 0.4 gram of rosin and 0.2 gram of the rosin-maleic anhydride reaction product. In this instance, the dispersion of the rosin-maleic anhydride reaction product was 100% neutralized. Paper prepared from the resulting stock showed 4'71 seconds sizing on being tested by the ink penetration method, while paper which had been prepared and sized in the same way, but using 0.6 gram of rosin instead of the combination of rosin and rosin-maleic anhydride reaction product, showed only 155 seconds sizing. Example VI Alkaline dispersions of rosin and rosin-maleic anhydride reaction product were prepared con taining 30 grams per liter of rosin and the reaction product, respectively. The rosin dispersion was '70 neutralized, and the dispersion of the reaction product was 50% neutralized. Sufficient of these dispersions were added to 1500 cc. of a suspension of bleached Gatineau sulfite pulp containing 30 grams of dry pulp to deposit 0.225 gram of rosin and 0.075 gram of rosin-maleic reaction product on the pulp. The resulting mixture was agitated for about 15 minutes, after which 3.5% of aluminum sulfate on the weight of the dry pulp was added. After another 15 minutes of agitation, the stock was made into paper, and was tested by the standard ink penetration method, showing 283 seconds sizing. On sizing the same stock in the same manner as described above, but applying 0.3 gram of rosin instead of the combination of rosin and rosinmaleic anhydride reaction product, and on testing the paper prepared therefrom by the ink penetration method, only 122 seconds sizing was obtained.

Similar tests were made on alpha pulp, using rosin alone as well as rosin in combination with other resinous reaction products of the general class hereinbefore described, but otherwise following the methods of Examples II and III. .The amount of sizing obtained with the various sizing agents or combinations of sizing agents used is given in the following table:

It is to be understood that the per cents of rosin referred to in the above table are based on the weight of the dry pulp being treated, while the per cents of resinous reaction product are based on the weight of the rosin used.

In order to show further the efiectiveness of the sizing adjuvants of the present invention, comparative tests were made with various kinds of pulp and with varying amounts of the sizing agent, using the standard ink penetration method. This method, which is one of the most commonly used, involves making a boat of a test sheet of previously sized paper, floating the same upon a bath of ink, and noting the time (usually in seconds which passes before a shade of coloration appears on the upper surface of the sheet. In each instance certain samples of the test papers were sized with a rosin dispersion alone, while other samples of the same kinds of paper were sized with the rosin dispersion and proportional amounts of the rosin-maleic reaction product dispersion prepared as hereinbefore described. To reduce variables to a minimum, the tests were made in each instance with a dispersion of G grade rosin which had been 70% neutralized, with the use of 1% of aluminum sulfate based on the weight of the dry pulp, and with the final pulp suspension (after the sulfate addition) at a pH of 4. In each of those instances where the rosin-maleic reaction product was used in conjunction with the rosin, it was employed in an amount equal to 20% of the weight of the rosin employed.

The results of the various tests are given in the following tables:

BLEACHED KRAFT PULP Rosin+Rosin- Rosin Alone Maleic Reaction Product Seconds Percent Seconds Percent Rosm 'zing Rosin Sizing S ULFITE P ULPS Rosin+ Rosin- Rosin Alone Maleic Reaction Product Seconds Percent Seconds Percent R051 Sizing Rosin Sizing RA G P ULP Rosin+Rosin- Rosin Alone Maleic Reaction Product Seconds Percent Seconds Peceut Sizing Rosin Sizing ALPHA PULP Rosin+ Rosin- Maleic Reaction Product Rosin Alone Percent Rosin Seconds Seconds Sizing Percent Rosin Sizing The above tables clearly show that the eniciency of rosin as a sizing material is markedly increased, when rosin-maleic reaction product is employed therewith to the extent of 20% by weight of the rosin. Thus, it is possible to obtain either a much larger amount of sizing with an equivalent amount of rosin, when the rosinmaleic reaction product is employed, or the same degree of sizing may be obtained with considerably less rosin. This is of great advantage to the papermalrer, particularly in those instances where it is, desired to obtain a maximum amount of sizing at minimum cost. In the preparation of the dispersions of rosin or the resinous reaction products of the invention, it is usually necessary to first prepare a relatively concentrated dispersion, as it is difiicult to form dilute dispersions directly without employing excessive amounts of alkali. Moreover, the preparation of a preliminary concentrated dispersion is of considerable advantage to the papermaker, who usually does not make his own sizing agents as it permits considerable saving in freight. It is possible in some instances to add the concentrated dispersion directly to the beater without first forming a dilute dispersion, but in general it is preferable to dilute the dispersion before adding it to the beater. In preparing dispersions of the resinous reaction products, the reaction product is partly or wholly neutralized with caustic soda, caustic potash, soda ash or other alkali metal base.

Although it is possible to employ the resinous adjuncts of the invention in widely varying amounts, it is usually not practical to employ less than 20% or more than 50% of the reaction product based on the weight of the rosin used. Smaller amounts do not increase the sizing efficiency as much as is usually desired, while larger amounts give less and less increase in sizing as the amount is increased.

This application is a continuation-in-part of Serial No. 538,708, filed June 3, 1944, which was a division of Serial No. 452,670, filed July 28, 1942, both now abandoned.

What is claimed is:

1. The method of sizing paper which comprises charging a beater with a predetermined amount of paper pulp, adding to the pulp a sufiicient amount of an aqueous and at least artly neutralized dispersion of rosin to supply from to 4% of rosin based on the weight of the dry pulp, beating the rosin dispersion into the pulp, thoroughly mixing with the thus treated pulp a sufiicient amount of an aqueous and at least partly neutralized dispersion of the reaction product of 1 mol of rosin and from about 0.25 to 1 mol of maleic anhydride to supply from 20 to 50% of said reaction product based on the weight of the pre viousiy added rosin, and then admixing with the pulp about 1 to 5% of aluminum sulfate based on the weight of the dry pulp.

2. Paper sized with to 4% of rosin, 1 to 5% of aluminum sulfate based on the fiber, and 20 to 50%, based on the weight of the rosin, of the reaction product of 1 mol of rosin and from about 0.25 to 1 mol of maleic anhydride.

3. Paper sized with /4 to 4% of rosin,1 to 5%:

of aluminum sulfate based on the fiber, and 20 to 50%, based on the weight of the rosin, of the reaction product of 1 mol of rosin and from about 0.25 to 1 mol of fumaric acid.

4. Paper sized with /4 to 4% of rosin, 1 to 5% of aluminum sulfate based on the fiber, and 20 to 50%, based on the weight of the rosin, of the reaction product of 1 mol of rosin and from about 0.25 to 1 mol of citraconic acid.

5. Paper sized with /q. to 4% or rosin, 1 to 5% of aluminum sulfate based on the fiber, and 20 to 50%, based on the weight of the rosin, of the reaction product of 1 mol of rosin and from about 0.25 to 1 mol of itaconic acid.

6. Paper sized with A; to 4% of rosin, 1 to 5% of aluminum sulfate based on the fiber, and 20 to 50 based on the weight of the rosin, of the reaction product of one mol of rosin with from about onequarter to one mol of a compound selected from the group consisting of maleic, fumaric, itaconic and citraconic acids and their anhydrides.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,978,598 Peterson Oct. 30, 1934 1,997,366 Kern Apr. 9, 1935 2,063,541 Ellis Dec. 8, 1936 2,063,869 Ellis Dec. 8, 1936 2,081,889 Borglin May 25, 1937 2,197,383 Outterson Apr. 16, 1949 2,230,230 Boggs Feb. 4, 1941 2,249,118 De Witt July 15, 1941 2,315,675 Trommsdorfif Apr. 6, 1943 2,380,043 Hochwalt July 10, 1945 2,383,933 Bump Sept. 4, 1945 2,385,794 Chappell Oct. 2, 1945 2,386,033 Chappell Oct. 2, 1945 2,418,450 Auer Apr. 8, 1947 FOREIGN PATENTS Number Country Date 355,281 Great Britain Aug. 12, 1931 OTHER REFERENCES Ind. and Eng. Chem, vol. 22, pages 272-278, 1940.

Manufacture of Pulp and Paper, 2nd ed., vol. IV, Sec. 4, pages 40, 42 and 48-51; pub. by McGraw-Hill, New York (1927) Wilson et al.: Paper Trade J., vol. 117, No. 21; 29-34 (1943).

Bainbridge: Institute of Paper Chem. Bull, vol. 15, p. 468 (1945).

Claims

6. PAPER SIZE WITH 1/4 TO 4% OF ROSIN, 1 TO 5% OF ALUMINUM SULFATE BASED ON THE FIBER, AND 20 TO 50%, BASED ON THE WEIGHTT OF THE ROSIN, OF THE REACTION PRODUCT OF ONE MOL OF ROSIN WITH FROM ABOUT ONE-QUATER TO ONE MOL OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF MALEIC, FUMARIC, ITACONIC AND CITRACONIC ACIDS AND THEIR ANHYDRIDES.