US3390004A - Manufacture of paste rosin size in closed circuit reactor - Google Patents

Description

June 25, 1968 J, c. 0| PLACIDO 3,39

MANUFACTURE OF PASTE ROSIN SIZE IN CLOSED CIRCUIT REACTOR Filed Sept. 1, 1965 INVENTOR. JOH/V CARL DiPLAC/DO A TTOR/VEY United States Patent 3,390,004 MANUFACTURE 0F PASTE ROSIN SIZE IN CLOSED CIRCUIT REACTOR John Carl Di Placido, Mobile, Ala., assignor to American Cyanamid Company, Stamford, Conn., a corporation of Maine Filed Sept. 1, 1965, Ser. No. 484,263 2 Claims. (Cl. 106238) ABSTRACT OF THE DISCLOSURE Paste rosin size is manufactured by introducing hot paste rosin size, hot aqueous alkali metal alkali solution, and molten rosin in appropriate proportions into the vortex of a centrifugal pump rotating sufficiently rapidly to emulsify the rosin.

The present invention relates to an improvement in the saponification of rosin with aqueous alkali metal solution to form paste rosin size.

Paste rosin size (rosin saponified with aqueous sodium hydroxide or other aqueous alkali metal solution to a solids content of about 60%80% solids by weight and a free rosin acid content of about 5% to 25%) can be cheaply and simply prepared by the continuous process disclosed in Anderson et al. US. Patent No. 2,842,453. According to this patent, molten rosin and hot aqueous alkali metal alkali solutions are piped in paste rosin sizemaking proportions (along with hot paste rosin size) to a centrifugal pump in which the rosin is emulsified, with conversion of the rosin to paste rosin size state. (In commercial practice, the components are metered separately and automatically and are introduced under pressure into the closed circuit of the reactor.) The rosin is rapidly emulsified by the whirling action of the pump (the paste rosin size acting as emulsifying agent) and reacts with the alkali metal alkali, forming paste rosin size.

While this method has greatly simplified the manufacture of paste rosin size, in large-scale operation, it has been diflicult to supply the molten rosin and alkali metal alkali solution into the centrifugal pump at a uniform continuous rate without use of high injection pressures. When these components are introduced at moderate pressure into the piping, severe oscillations occur in the rate at which the rosin and alkali metal alkali solutions are metered with corresponding variations in the quality of the size which is discharged from the pump. The cause of these variations has not been ascertained, but is probably the tendency of the rosin to travel as slugs rather than as a uniformly distributed component of the reaction mixture. It became desirable, therefore, to overcome these difficulties without use of special auxiliary equipment or specially responsive controls.

The discovery has nOW been made that the aforementioned ditficulties are obviated in the process described when the alkali metal alkali solution and rosin are introduced directly into the vortex which is present at the inlet side of the centrifugal pump when the pump is working at emulsification speed. I have found that as a result, the two materials pass smoothly and uniformly into and through the pump from their time of introduction, and undergo much more uniform reaction than has heretofore been the case. Emulsification of the rosin to paste rosin size consequently takes place almost instantly and uniformly, typically within about second, with production of a better and more uniform grade of paste rosin size than heretofore produced.

At the present time, paste rosin size may contain minor amounts of sodium chloride, potassium chloride or a lower alkanol as fiuidifying agents, and pentachloro- 3,390,004 Patented June 25, 1968 phenol as a mold growth inhibitor. These and other special additives such as are customarily present in rosin size may be introduced separately into the centrifugal pump or, if preferred, they may be metered into the alkali metal alkali solution, the molten rosin, or the paste rosin size product as appropriate in each instance.

The invention is further illustrated by the drawing wherein:

FIGURE 1 is a schematic elevation of an electric motor-driven centrifugal pump provided with supplementary inlet pipes which permit the pump to be used for the practice of the present invention;

FIGURE 2 is an enlarged view of the inlet cover and upstream half of the collar of the feed side of the pump, showing the arrangement and length of the feed pipes therein;

FIGURE 3 is a view into the component of FIGURE 2 presenting a different vieW of the arrangement of the inlet pipes; and

FIGURE 4 is a view into the centrifugal pump from the feed side with the inlet cover and collar removed, showing the impeller vanes of the pump, the area typically occupied by the eye of the vortex, and the area over which the feeds are introduced into the pump.

In the drawings, the same numbers are used to identify the same parts.

In FIGURE 1, 1 represents a centrifugal pump supported on bearing casing 2 driven by variable speed electric motor 3 and having an inlet collar 4. To this collar (which contains the vortex when the pump is in normal operation) is affixed flanged conical inlet cover 5a having axial supply orifice 5b, alkali metal alkali supply pipe 6, and molten rosin supply pipe '7. The pump has tangential exit orifice 8. The pump collar and cover are of conventional design except for pipes 6 and 7, which are present to permit practice of the present invention.

In FIGURE 2, the alkali metal alkali supply pipe 6 is shown as extending axially beyond the flange of cover 5:: by a distance sufiicient to introduce the solution into the eye of the vortex which forms in collar 4 when the pump is in operation. Rosin supply pipe 7 terminates in an adja cent location 50 as to ensure most rapid contact between the rosin and the alkali metal alkali soiution.

In FIGURE 4, the inlet area is shown as extending over the entire inlet face of the pump (the area ringed by collar 4- as indicated by S and is coextensive with the area swept by impeller vanes 10. The periphery of a typical vortex is indicated by dotted circle 11.

In operation, paste rosin size having a temperature above the melting point of rosin is admitted under pressure through axial pipe 5b into inlet cover 5a which distributes paste rosin size as emulsifying medium uniformly over inlet face 9 of the pump. The pump is operated at least sufficiently fast to emulsify the rosin.

Hot alkali metal alkali solution and molten rosin are respectively admitted under pressure from automatic meters (not shown) through pipes 6 and 7 in proportions suitable for formation of paste rosin size.

Best emulsification and reaction of the rosin has generally occurred when the ratio of the volume of the paste rosin size which is admitted as emulsifying agent to the combined volumes of the molten rosin and alkali metal alkali solution is between 3 :1 and 5:1.

The present invention is usefully employed in the process of said Anderson et al. patent, wherein a closed circuit reactor is employed, and the rosin and alkali metal alkali solution are emulsified in recirculated paste rosin size.

The invention need not be practiced in the specific form of apparatus shown in the drawing. Thus, for example, the pipe for admitting the rosin to the vortex in the pump need not be adjacent to the pipe used for admitting the alkali metal alkali solution but may be concentric therewith.

I claim:

1. In the continuous manufacture of paste rosin size by a process wherein molten rosin and aqueous alkali metal alkali solution in paste size making proportions and paste rosin size as emulsifying medium for said rosin are piped to a centrifugal pump rotating at sutficient speed to form a vortex on its intake side and to emulsify said rosin, the improvement which consists in introducing said alkali metal alkali solution and said rosin into said vortex, whereby said alkali metal alkali solution and said rosin References Cited UNITED STATES PATENTS 7/1951 Russell 25996 7/1958 Anderson et al l06238 ALLAN LIEBERMAN, Primary Examiner.

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