JP2515983B2 - Emulsifier for neutral papermaking - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an emulsifying apparatus for neutral papermaking. More specifically, the present invention relates to an emulsification device capable of producing an oil-in-water emulsion of a liquid sizing agent having an excellent size effect in a neutral papermaking method using a liquid sizing agent and a surfactant.

(Prior art and problems) In the past, in general, a large amount of fillers such as talc and clay has been used in the paper manufacturing process in order to improve printability and whiteness, impart opacity, etc. In lieu of this, there is an increasing trend to use calcium carbonate, which exists in large quantities in Japan and is inexpensively available. However, so-called anionic sizing agents, such as rosin-based sizing agents that have been commonly used as papermaking sizing agents, are used in the acid sizing method of fixing to pulp with a sulfuric acid band, and therefore when calcium carbonate is used as a filler, There is a drawback that calcium carbonate is decomposed by the acidity of the papermaking system.

Therefore, recently, in order to solve this problem, various so-called neutral sizing agents have been proposed which can perform sizing in a neutral region without using a sulfuric acid band.

For example, an addition reaction product of olfine and maleic anhydride is known as a sizing agent which reacts with a hydroxyl group of cellulose fiber to form an ester bond to exert a sizing effect. These maleic anhydride addition products are usually emulsified with a homomixer, homogenizer, colloid mill, or other emulsifying device using a water-soluble polymer compound such as cationized starch or a surfactant such as polyoxyethylene alkylaryl ether. , Added to the stock in the form of an oil-in-water emulsion. However, in order to reduce the amount of the surfactant added and increase the size effect, an emulsifying device that can easily control the stirring force has been desired.

However, it is difficult to control the stirring force of the emulsifying device such as the above-mentioned homomixer, homogenizer, colloid mill and the like, and it is difficult to effectively exert the size effect of the sizing agent.

(Means for Solving the Problems) In view of the above situation, the present inventors have conducted various investigations, and as a result, conducted a neutral papermaking process which is cheaper than the conventional one and can effectively exhibit the size effect of the liquid sizing agent. Invented an emulsifying device for use.

That is, as shown in FIG. 1, in a neutral papermaking method using a liquid sizing agent and a surfactant, a pressure pump (P) and an aqueous solution supply line (1) on the suction side of the pressure pump (P), An injection nozzle (N) for primary stirring and a line (2) for supplying a mixed liquid of a liquid sizing agent and a surfactant between the injection nozzle (N) for primary stirring and the pressure pump (P). The secondary stirring orifice mixer (L) is connected to the discharge side of the pressure pump (P), and a part of the high-pressure liquid on the discharge side of the pressure pump (P) is injected into the injection nozzle (N) for primary stirring. Piping for more jetting (3)
Further, the inventors have invented an emulsification device for neutral papermaking, which is equipped with a circulation line (5) including a control valve (4) for controlling the discharge side pressure of the pressurizing pump (P).
The plate portion (M) of the secondary stirring orifice mixer (L) preferably has a biconvex lens shape in cross section.

 A vortex pump is suitable as the pressurizing pump.

(Function) In the neutral papermaking method, the concentration of the liquid sizing agent when used as an oil-in-water emulsion is usually 0.02 to 2%.
And the concentration of surfactant is 0.5-1 of liquid sizing agent.
0%, so 0.000 of surfactant in aqueous solution
The concentration is 1 to 0.2%. In order to produce a stable emulsion with a small amount of surfactant in this way, the stirring force is adjusted to suit each condition and the liquid size is made to have an optimum particle size distribution, and the size effect is effective. It is essential to express it.

That is, if the particle size distribution is too large, the liquid sizing agent separates and floats in the form of a film above the water, or if the particle size distribution is too fine, the area of the interface becomes too large, It is difficult to maintain the formation of even a monomolecular film on the activator, which deteriorates stability and reduces the size effect.Therefore, stirring force is added according to the amount of liquid size and surfactant to improve the size effect. Effective expression is important.

When the emulsifying apparatus according to the present invention is used, preliminary emulsification is performed by the nozzle for primary stirring, then pressure is applied by the pressure pump, and then the pressure of the orifice mixer for secondary stirring (L) is controlled by the pressure control valve. Only by doing so, it is possible to easily adjust the stirring force, and further, it is possible to make the liquid sizing agent have an optimum particle size distribution and to effectively exert the sizing effect.

Examples of the liquid sizing agent used in the present invention include alkyl or alkenyl succinic anhydride.

(Examples) Next, examples of the present invention will be specifically described, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Example and 2 Comparative Examples 1 and 2 (Effects of the Invention) As is clear from the above-mentioned Examples and Comparative Examples, when emulsification is performed using the emulsification device according to the present invention, a superior size effect is obtained as compared with conventional devices.

[Brief description of drawings]

FIG. 1 is a drawing showing an embodiment of the present invention, FIG. 2 is a plan view of a plate portion of an agitating orifice mixer of the present invention, and FIG.
The drawing is a central cross-sectional view of the plate portion of the FIG. 2 orifice mixer. 1 ... Aqueous solution supply line 2 ... Line for supplying a mixture of a sizing agent and a surfactant 3 ... Pipe for injecting a part of the high-pressure liquid from the injection nozzle (N) for primary stirring 4 ... Pressure control Valve 5 ... Circulation line 6 ... Pressure gauge 7 ... Valve P ... Pressurizing pump N ... Primary stirring jet nozzle L ... Secondary stirring orifice mixer M ... Secondary stirring orifice mixer plate E: Oil-in-water emulsion S: Mixture of liquid sizing agent and surfactant

Claims (2)

(57) [Claims] 1. An emulsifying apparatus for neutral papermaking using a liquid sizing agent and a surfactant, which comprises a pressure pump (P), and an aqueous solution supply line (at the suction side of the pressure pump (P) ( The return line (3) branched from the discharge side pipe of the pressurizing pump (P) is connected to 1), and the tip of the return line is inside the aqueous solution supply line and the injection nozzle (N) for primary agitation is connected. ), This injection nozzle (N)
A line (2) for supplying a mixed liquid of a liquid sizing agent and a surfactant is connected to the aqueous solution supply line (1) between the pressure pump (P) and the discharge side of the pressure pump (P). A secondary stirring orifice mixer (L) is arranged in the pipe downstream of the return line branching portion, and a pressurizing pump (P) is further provided.
An emulsification device for neutral papermaking, comprising a circulation line (5) including a control valve for controlling the discharge side pressure of the. 2. The emulsifying device for neutral papermaking according to claim 1, wherein the plate portion (M) of the secondary stirring orifice mixer (L) has a biconvex lens shape in cross section. .