US2873203A - Liquid rosin sizes containing anti-stratifying agent - Google Patents

Description

LIQUID ROSIN SIZES CONTAINING ANTI-STRATIFYING AGENT William C. Hopkins, Valdosta,

Jr., South Charleston, Cyanamid Company, of Maine Ga., and John G. Senese, W. Va., assignors to American New York, N. Y., a corporation No Drawing. Application February 25, 1954 Serial No. 412,636

5 Claims. (Cl. 106-438) Rosin sizes have their principal use in the manufacture United States Patent 0 of paper. These sizes are manufactured on a large commercial scale by heating a natural or modified rosin above its melting point, forming a hot caustic solution from Water and an alkali metal alkali such as potassium or, more commonly, sodium hydroxide or carbonate, and reacting the alkali solution with the rosin. The rosins referred to are organic acids. Neutralization of these acids by the caustic takes place within a few hours, the product being a viscous soap dispersion. In this process, the amount of water employed is controlled so that the size contains between about 50% and 80%85% of size solids, on the one hand to avoid sizes so dilute that they cannot be shipped economically, and on the other hand to avoid sizes so concentrated and, therefore, viscous that they cannot be pumped.

The amount of alkali employed in this manufacture is at least about 60% of that requiredfor complete neutralization so that the size contains up to about 40% of free rosin acids, based on the weight of the solids therein, a lower amount of alkaliyielding a size which contains so much free rosin acids that it cannot be successfully diluted for application to paper. On the other hand, the amount of alkali may be sufficient to completely neutralize the rosin, and this yields satisfactory sizes.

In commercial practice, liquid rosin sizes generally contain between 60% and 80% of size solids by weight,

thus minimizing shipping costs while providing a product having a pumpable viscosity at a temperature of about 60-70" C., this being the standard temperature at which sizes are handled within paper mills. Moreover, suflicient alkali is used to cause at least 95 %75 neutralization of the rosin, this amount insuring that the rosin possesses excellent dilutability in water while maintaining consumption of alkali and the viscosity of the product at minimum practical values.

Frequently, liquid rosin sizes are stored by the manufacturer before they are shipped in tank cars, and these sizes are further stored by paper manufacturers before use. It is known that during these periods of storage liquid rosin sizes of the commercially practicable types I mentioned, that is, sizes containing from about 5% to of free rosin acids and about 60% to 80% of solids, stratify on storage and separate into two layers. The

bottom layer is more viscous than the upper layer. Hence,

when a liquid rosin size has been prepared of maximum pumpable viscosity, allowance being made for the increase in viscosity which normally takes place on agmg, storage of the sizeresults in separation of a bottom layer which A further disadvantage is that the upper layer is usually 2,873,203 Patented Feb. 10, 1959 darker in color than the lower layer, and this introduces a problem of color control in the manufacture of paper.

Stratification of liquid rosin size often becomes evident in the laboratory in 3-5 hours and, in the case of rosin stored in large commercial tanks, in about 3 days. The phenomenon is not spontaneously reversible and homogeneity can be obtained only by thorough mixing of the contents of the tank.

The discovery has now been made that liquid rosin sizes of the composition mentioned containing a small amount of sodium chloride do not stratify or otherwise separate on storage. The stratification is inhibited by the presence therein of between about 0.7% and 2% by weight of dissolved sodium chloride based on the weight of solids in the size and substantially completelyinhibited by the presence therein of between about 2% and 5% by weight of-dissolved sodium chloride based on the weight of solids in the size. It has further been found that separation of the sizes into phases takes place when more than about 5% of sodium chloride is present, the sodium chloride in this instance acting to salt out the rosin soap resulting also in an actual increase in viscosity of the size.

. From the foregoing it will be seen that the subject matter of the present invention comprises a liquid rosin size of about 5% to 25% free rosin acids content containing about 60% to size solids by weight, said size being inhibited against Stratification on storage by the presence of an effective amount between about 0.7% and 5%, based on the weight of the solids, of sodium chloride dissolved therein, the amount of said sodium chloride being insufiicient to salt out said size.

The amount of sodium chloride which should be present within the range mentioned varies with the type of rosin employed, the solids content of the size, the amount of free rosin acids in the size, and the temperature of the size. As a result, the minimum effective amount can best be determined in each instance by laboratory trial. In general, with regard to liquid rosin sizes of the composition mentioned, we have found that. fortified rosin sizes of low solids content but containing an intermediate amount of free rosin acids show the greatest and most rapid stratification, and that with regard to these sizes, higher temperatures favor Stratification. For example, a fortified rosin size containing 60% or 70% solids and 15% of free rosin acids is particularly prone to stratify and requires somewhat more sodium chloride for stabilizationat the upper normal storage temperature of 80 C. than does ordinary rosin size containing 80% solids and 15% free rosin acids at the lower normal storagetemperature of 50 C.

In place of sodium chloride, no reason is known why other alkali metal halides such as sodium bromide and sodium iodide as well as the corresponding potassium salts are not also effective, and these salts are therefore included within the broad scope of the present invention.

Because of its ready availability and the excellent results which it affords, sodium chloride is preferred, and in commercial practice common rock salt has proved entirely satisfactory.

In addition toinhibiting stratification it is a most important advantage of the present invention that the presence of sodium chloride very greatly decreases the viscosity of the sizes often to only a small fraction of the values which they would otherwise possess.

ture falls, and since rosin sizes are normally stored in heated storage tanks, this means that rosin in such tanks can be stored at lower temperatures than would otherwise be the case. It is the customary practice of paper .mills to store rosin size in tanks maintained at a temperature between about 60-70 C. The presence of sodium Since the t viscosity of liquid rosin sizes increases as their temperachloride permits the same sizes' to be stored at a temperature about20 C. lower without increase inv viscosity, .thus permitting substantial economy in the heat supplied.

It is a further advantage that the sodium chloride does Example 1 'The efiiect of sodium chloride ininhibiting stratification and decreasing the viscosity of a liquid fortified rosin size is illustrated as follows.

A I 15,000 pounds of M gra e gum rosin to an ma i ii ih e iffifiiz vi i li iii {82 221 1 2 zi g fggi slowly adding 600 pounds of malerc anhydrrde. Reacp i D tion of the maleic anhydride was complete in 3 hours creases rapldly 1n viscosity during the course of about at about C the product being fortified rosin the ifirst seven days, the viscosity at that time often being containing the A1 def rosin maleic anhydride several times that of the initial viscosity of the material. Product Thereafter the viscosit of the size enerall remains at or near the high valu reached towirds the end of the In Separat? vessel 1800 Pounds of sodlum hydrpxlde first week of storage It is a further most important adwas dlssolved 5 7 9 pomllds of wlater 5 t heated to 95 e mo ten ma eate rosin an e n a h a no 0" s dlum chloride 1s a ermanent die t lfe t aib ilized sii es ot the present inventi hn having hot causuc Sohmon were Separately but slmultanecusy a much lower viscosity during and after this period than ;2 :5 :2 i gf r j g i g ifigg 52322 corresponding sizes containing no sodium chloride. ag

In the manufacture of the liquid rosin sizes to which the caustlc CmFPIetC m 2 hours The resulting S126 the present invention is directed, numerous forms of 1:3 23% 2 aclds content of 15% and a sohds conrosin are currently employed and include gum rosin, A wood rosin, and tall oil rosin, the latter being a new de- T Your i 1 a f 2:12 g gf g sd velopment in the rosin field for which standards have 0 one P e a e c been promulgated by the Department of Agri aqueous sod um chlorlde solutron to provide 0.7% of culture Moreover resins may be employed which 25 sodium chloride based on the weight of the solids therein. tain a minor amourit, e. g. 10% to 40% by weight of the To the Second. h control Sample) was ldF an equal Diels-Alder adducts formed by reacting a naturallyvolume of delomzed t To h remammg sampies occurring rosin with maleic anhydride or similar material. ii saglraied iodmm chlondfi solutloifio provllde These rosins and the sizes prepared therefrom, generally sodmm c on e 6 t 6 y? 8 g fi respectively termed fortified rosins and fortified rosin i? stofed at 8 an 0 Serve perm lea y or Sizes are disclosed broadly in S Patents 2,628; stratification. In addition, small amounts were removed 918 and 2 385 periodically from the control sample and Sample A and It will mlderstood that liquid rosin Sizes in addi their viscosity determined at the temperatures noted, the tion to the foregoing, commonly contain a number of entlre sample belng first made homogeneous by stn'rlng other materials. Included are the lower aliphatic alcobefore E Sfnan amounts were wlthdrawn' hols and rosin esters therewith since rosin size may be Stratlficatlon deemed to take P151Ce when two prepared f rosin estem Moreover, natural resins tlnct layers of dliferent color could be observed. The contain small amounts of unsaponifiable materials in- P were ratefi an Y Scale 011 Whlcl} 4 cluding lignin and stearols. Sizes containing these matelndlcatfis bad Stratlficatlon, 1 lndlcates p ly slfght rials undergo stratification on storage and the present 40 Stratification, and 0 indicates no noticeable stratification. invention is advantageously employed therewith. Results are as follows:

P t. Viscosity 2 at C. Viscosity 1 at 71 0.

en Sample N 58] Start 4Days 7Days 12 Days Start 4Days 7Days 12 Days ContL- Nil 17, 700 57,000 75. 000 47, 500 2,500 9,500 11, 500 8,400 A 0. 5, 000 7,000 17,000 8,500 1,000 1,20 1,800 1, 500 2.0 IIII IIII IIII IIII IIII IIII IIII IIII gaseil 0111 solids content of size.

en p0 SE5.

The sodium chloride may be introduced at any desirable point in the manufacture of the rosin size. For ex- Stratificatio'n ample, it may be dispersed into the molten rosin itself Sample or may be dissolved in the liquid size subsequent to its 4Days 7Days 12 Days preparation. Since, however, liquid rosin size is normally produced on a very large industrial scale it has 60 n] 4 4 4 been found most convenient to dissolve the sodium chlog 1 ride in the water in which the alkali metal alkali is dis- 0 0 0 0 solved. In this manner uniform distribution of the antistratification agent is most readily effected, and separate 1 On storage at 80 0. metering of the agent becomes unnecessary.

These tests show that the presence of 0.7% and 1.25% of sodium chloride inhibits stratification and that increasing the amount to 2% substantially prevents stratification. The tests further show that only 0.7% of sodium chloride causes a sharp reduction in the viscosity of the size throughout the test. From previous experience it is known that the viscosity of rosin sizes containing 2%5% of sodium chloride is less than the viscosity of similar sizes which contain 1.25% of sodium chloride.

Example 2 The effect of increasing amounts of sodium chloride upon the stratification of and viscosity of resin size is illustrated by the following.

A fortified rosin size containing 72.5% solids and 9.6% free rosin was made by the method of Example 1, and a control sample and sodium chloride-containing samples were prepared also as described in Example 1. The initial viscosity of these samples was determined at 71 C. The samples were stored at 71 C. for two days and ob served for stratification. Results are as follows, the stratification index being that of Example 1.

Stratification at 2 Days Percent N M31 1 Viscosity at 71 0. (ep.)

ssiia Out...

asraaoa weight of said solids, of sodium chloride dissolved therein, the amount of said sodium chloride being insuflicient to salt out said size.

2. A liquid rosin size which is a uniform aqueous dispersion containing from about to 80% rosin size solids by weight, and 5% to 25% of tree rosin acids based on the weight of said solids, said size being sta bilized against stratification on storage by the presence of an effective amount between 2% and 5%, based on the weight of said solids, of sodium chloride dissolved therein, the amount of said sodium chloride being insuflicient to salt out said size.

3. A liquid maleated rosin size according to claim 2.

4. A liquid rosin size which is a uniform aqueous dispersion containing about rosin size solids by weight, and about 15% free rosin acids based on the weight of said solids, said size being stabilized against stratifica tion on storage by the presence of an effective amount between 2% and 5%, based on the weight of said solids, of sodium chloride dissolved therein, the amount of said sodium chloride being insufiicient to salt out said size.

5. A liquid maleated rosin size according to claim 4.

References Cited in the file of this patent UNITED STATES PATENTS 83,707 Gray Nov. 3, 1868 405,269 Menzies June 18, 1889 2,192,488 Reilly Mar. 5, 1940 2,213,943 Auer Sept. 10, 1940

Claims (1)

1. A LIQUID ROSIN SIZE WHICH IS A UNIFORN AQUEOUS DISPERSION CONTAINING FROM ABOUT 60% TO 80% ROSIN SIZE SOLIDS BY WEIGHT, AND 5% TO 25% OF FREE ROSIN ACIDS BASED ON THE WEIGHT OF SAID SOLIDS, SAID SIZE BEING INHIBITED AGAINST STRATIFICATION ON STORAGE BY THE PRESENCE OF AN EFFECTIVE AMOUNT BETWEEN 0.7% AND 5%, BASED ON THE WEIGHT OF SAID SOLIDS, OF SODIUM CHLORIDE DISSOLVED THERE, THE AMOUNT OF SAID SODIUM CHLORIDE BEING INSUFFICIENT TO SALT OUT SAID SIZE.