JPH0215676B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a sizing emulsion, and more particularly to a method for producing a sizing emulsion suitable for improving the emulsification process and obtaining paper with excellent sizing effects. A typical papermaking method involves blending a sizing agent, an emulsion, and, if desired, an emulsification auxiliary with water and thoroughly stirring the resulting sizing emulsion, which is then blended with other additives into a pulp suspension, followed by papermaking, It consists of dehydration and drying. In this paper manufacturing process, the process of producing a sizing emulsion is generally carried out by adding a sizing agent, an emulsifier, etc. to water and stirring the mixture at high speed using a high-speed mixer, high-speed homogenizer, or the like. However, this stirring requires a large amount of electric power, and the size effect of paper produced using the obtained emulsion was not necessarily satisfactory. The present inventors have conducted various studies regarding the method for producing an emulsion for size. In the process,
When adding sizing agents, emulsifiers, etc. to water,
Attempts were made to spray these components into water using a nozzle. In this case, the influence of the nozzles was investigated using nozzles whose tips had rectangular, square, triangular, or circular cross-sectional shapes. As a result, good results can be obtained when using a nozzle whose tip has a rectangular cross-sectional shape.
Furthermore, when the ratio of the lengths of the long side L and the short side D of the rectangle is set to a predetermined value, and the length of the short side D is set to a predetermined value, paper having an excellent size effect is used. They have discovered that it is possible to prepare an emulsion suitable for obtaining the following, and have completed the present invention based on this knowledge. That is, in the present invention, water is filled in a container equipped with stirring means, and a mixture containing a sizing agent and an emulsifier is mixed.
Using a pump, the cross-sectional shape of the tip portion is rectangular, the ratio L/D of the length of the long side L to the short side D of the rectangle is 80 to 2000, and the length of the short side D is
The present invention provides a method for producing an emulsion for size, characterized in that the emulsion is injected into water from a nozzle having a diameter of 0.10 to 0.50 mm while the nozzle is immersed in water. In the present invention, any known sizing agent can be used, including substituted cyclic dicarboxylic anhydrides such as alkenyl succinic anhydride. Similarly, any emulsifier can be used, and an appropriate emulsifier may be selected from among anionic, cationic, and nonionic emulsifiers. In addition, components such as an emulsification aid typified by alkenyl dicarboxylic acid can be used as necessary. Furthermore, known conditions may be applied to the usage amounts of each of the above components. Next, the nozzle used for injecting the mixture containing the sizing agent and emulsifier into water has a rectangular cross-sectional shape at its tip, and the L/L of the rectangular shape is rectangular.
It is necessary to use one in which D is 80 to 2000, more preferably 100 to 1000, and the length of the short side D is 0.10 to 0.50 mm. If L/D is less than 80, the resulting emulsion cannot provide a sufficient size effect even if the injection speed of the mixture into water is increased. Note that when the mixture is injected into water using a nozzle, water is filled in a container equipped with a stirring means, and the mixture is injected while the nozzle is immersed in the water. Furthermore, it is desirable to inject the mixture while stirring the water. In that case,
As the stirring means, a propeller type stirring blade or the like may be used. According to the present invention, when producing a size emulsion, there is no need to use high-speed stirring means that requires a large amount of electric power, and there is no need to use chemicals or the like to improve emulsification. Paper having excellent sizing effects can be efficiently obtained by manufacturing paper by a conventional method using the sizing emulsion obtained according to the present invention. Next, the present invention will be explained in detail with reference to examples. Examples 1 to 6 and Comparative Examples 1 to 3 Water 40 was poured into a 45 container equipped with a stirring means, and while stirring at a rotational speed of 660 rpm using a propeller type stirring blade, 100 parts by weight of isobutyl succinic anhydride and nonionic sizing agent were added. Emulsifier (“Noogen”
A size mixture consisting of 9 parts by weight of "EA167" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and 5 parts by weight of isobutylsuccinic acid as an emulsification aid was added using a Chemide metering pump.
The cross-sectional shape of the tip is rectangular (dimensions are shown)
A size emulsion was prepared by injecting at a predetermined speed through a nozzle. Note that the nozzle was used by being immersed in stirred water. A mixture of the sizing emulsion thus obtained, a fixing agent (cationic starch), a filler (ground calcium carbonate) and a retention aid (cationic polyacrylamide) was mixed with sodium bicarbonate to pH 7. It was added to a 0.5% by weight hardwood bleached sulfate pulp suspension adjusted to .5% by weight. The amounts of each component added were three types: 0.1% by weight, 0.15% by weight, and 0.20% by weight of the emulsion, 0.8% by weight of the fixing agent, 20.0% by weight of the filler, and 0.03% by weight of the retention aid. All of these values are percentages of the pulp solid content. Next, 408 ml of freeness (JIS
P8121), a basis weight of 80 g/m ² and drying conditions of 110° C. and 2 minutes (rotary dryer) to obtain paper sheets.
The table shows the size effect of the paper sheets obtained (JISP8122, Stekicht method). Comparative Examples 4 to 7 The cross-sectional shape of the tip of the nozzle is circular (diameter 2 mm)
or 6mm) and triangular (base 4mm or 8mm)
Paper sheets were obtained in the same manner as in the example except that paper sheets (mm, height: 4 mm) were used. The measurement results for this paper sheet are shown in the table. 【table】

Claims (1)

[Claims] 1. Pour water into a container equipped with stirring means, and add a mixture containing a sizing agent and an emulsifier using a pump.
The cross-sectional shape of the tip part is a rectangle, and the ratio L/D of the length of the long side L and the short side D of the rectangle is 80 to 2000.
A method for producing a size emulsion, which comprises spraying into water from a nozzle whose short side D has a length of 0.10 to 0.50 mm while the nozzle is immersed in water.