JPS5951568B2 - Method for producing easily water-soluble polyacrylic acid metal salt granules - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves granulating an aqueous polyacrylic acid metal salt powder by a fluidized bed granulation method while spraying an aqueous solution of the polyacrylic metal metal salt to obtain easily water-soluble polyacrylic acid metal salt granules. Relating to a method of manufacturing.

Aqueous polyacrylic acid metal salts are used for various purposes such as food additives such as thickeners and emulsion stabilizers, coagulation sedimentation accelerators for industrial wastewater, soil conditioners, and cement additives. This substance is expected to be used as a treatment for peptic ulcers. This substance is usually used as an aqueous solution, but it has the disadvantage of very poor solubility in water due to its strong hygroscopicity and stickiness. To improve this drawback, water or a water-containing hydrophilic organic solvent is added to the powder of sodium polyacrylate, the mixture is kneaded, and then this is dried and then crushed or granulated and dried to form granules (especially 18368-8368-1983 also, powder of alkali metal salt of polyacrylic acid is brought into contact with water in a hydrophilic organic solvent, the resulting lump is dried, and then crushed to form granules (Unexamined Japanese Patent Publication No. No. 50-133251), etc. However, the production yield of these products is as low as about 55%, and the production operation is also complicated.The present inventors therefore attempted to improve the above-mentioned drawbacks. As a result of various studies, we found that the dissolution rate was worsened by granulating water-soluble metal polyacrylate powder by fluidized bed granulation and using an aqueous solution of metal polyacrylate as a binder. It has been found that readily water-soluble polyacrylic acid metal salt granules of constant quality can be obtained with a yield of <about 80% without causing any damage.

The present invention was completed based on the above findings.

The easily water-soluble polyacrylic acid metal salt granules obtained in the present invention are composed of a large number of powder particles agglomerated to form one granule, and this structure makes them very easily water-soluble.

To specifically explain the present invention, a powder of an aqueous metal salt of polyacrylate was placed in a fluidized bed granulator, and while hot air was blown up from below to fluidize the powder, an aqueous solution of a metal salt of a polyacrylate was sprayed for a certain period of time. Then stop the spray for a certain period of time and allow the powder to flow (shaking).

This operation may be repeated until a predetermined amount of the aqueous solution is used up, and then the resulting granules may be dried.
The granules thus obtained can be sieved to obtain the desired particle size. In the case of the present invention, particles having a particle size larger than 80 meshes, preferably 12 to 60 meshes, are suitable. The water-soluble polyacrylic acid metal salt used in the present invention has a molecular weight of 500,000 to
10 million, preferably 5 million to .・10 million alkali metal salts, alkaline earth metal salts, trivalent metal salts, etc.

Moreover, the particle size is 20 to 300 mesh, preferably 50 mesh.
~200 mesh is good. The polyacrylic acid metal salt to be sprayed is preferably of the same type as the polyacrylic acid metal salt 1 to be granulated, and the aqueous solution thereof has a viscosity of 50 to 700 c·Ps, preferably 150 to 350 c·Ps.
p-S is good.

Any type of fluidized bed type, modified fluidized bed type, or spouted bed type can be used as the fluidized granulator, and there is no particular restriction. Next, it will be explained by experimental examples that the method of the present invention shows an excellent yield.

Experimental example (1) Raw material powder Sodium polyacrylate (hereinafter referred to as "PANA") 15 with an average molecular weight of 8 million and a particle size of 50 to 150 mesh
．． 5 kg (2) Preparation of Granules Granules having an average molecular weight of 8 million PANAO. O75w/
v% aqueous solution (298 c.p.s) Sample A polyvinylpyrrolidone 20% w/v% aqueous solution (215 c.p.S
) ... Control sample B 6% w/v% methylcellulose aqueous solution (304 c.p.s) ... Control sample C Using only water as a binder ... Control sample D JP-A No. 50-133251 Okosi granules produced by the method: Control sample E (3) Calculation of yield The yield was calculated using the following formula.

(4) Results Table 1 shows the results.

As is clear from this result, JP-A-50-133251
The yield of control sample D produced by the method is 54.7%, while that of sample A of the present invention is 80.1%,
In fact, a yield improvement of more than 40% is observed.

In addition, in the case of control samples B and C manufactured using polyvinylpyrrolidone and methylcellulose as binders, respectively,
The yields were only 63.2% and 60.5%, respectively, and the yield of control sample D prepared by spraying only water was 59.
Not much different from 1%. On the other hand, the yield of sample A of the present invention produced using PANA as a binder was 80.1%, an improvement of more than 30%, indicating that it is an excellent binder. Furthermore, Sample A of the present invention is superior to Control Samples B, C, and D in terms of granule strength.

Furthermore, by coating the granules of the present invention with a semipermeable membrane, the granules can be made to have even better solubility.

Example 1 Particle size distribution is 50-150 mesh, average molecular weight is 800
Fluidized granulation dryer 8WSG for 5.5 kg of PANAl
A 0.075 w/v% aqueous solution (298 c.p.s) 7.51 of PANA having the above molecular weight was sprayed at a spray pressure of 5 kg/v into a 115R model (manufactured by Okawara Seisakusho) while flowing at 50°C.
Cm2, and granulate with spraying at a feed rate of 120 m1/min.

At this time, start spraying, repeat the operation of spraying for 20 seconds and shaking for 5 seconds for 5 minutes, and then
Spray for 1 minute and shake for 5 seconds. After the granulation was completed, it was dried at 140° C. for 6 hours, and then sieved and classified using a Gyroscope filter to obtain granules of 16 to 48 meshes. The dissolution time was 75 minutes, which was the same as the dissolution time of Okosi granules produced by the method of JP-A-50-133251. Note that the dissolution time of the raw material powder for this granule was 320 minutes.

Example 2 Particle size distribution is 50-200 mesh, average molecular weight is 590
16.3 kg of PANA powder with the above molecular weight was placed in the same machine as in Example 1, and while fluidized at 55°C, PANA with the above molecular weight was added.
(7) 0.11W/V% aqueous solution (311C.p.S) 8
．． 11, spray pressure 4.5 kg/Cm2, feed speed 10
Granulate while spraying at 0 ml/min.

The spraying, drying and sieving methods were the same as in Example 1.
Granules of 6 to 48 meshes were obtained. The yield was 82.7% and the dissolution time was 70 minutes. Example 3 In Example 1, 15.1 kg of a water-soluble metal polyatalylic acid salt powder having a particle size distribution of 50 to 200 mesh and an average molecular weight of 7.8 million, in which 50% of the total carboxyl groups are sodium salt and 50% are aluminum salt, was prepared. By the same manufacturing method as 0.
15 w/v% aqueous solution of the same substance (267C.P.S) 7
．． 71 while spraying at a feed rate of 90 m1/min to obtain granules of 16 to 48 meshes.

At this time, the yield was 80.9% and the time required for dissolution was 65 minutes. Reference Example 1 5 parts of ethyl cellulose and 1 part of glycerin fatty acid ester (0.D.0 Nisshin Oil Co., Ltd.) were added to 15 kg of the granules of Example 1.
Spray coating was carried out using a coating liquid consisting of 1.5 parts of methanol, 47 parts of methylene chloride, and 47 parts of methylene chloride until the solid component weight increased by 900 g to obtain granules with excellent solubility.

Claims (1)

[Claims] 1. A method for producing easily water-soluble polyacrylic acid metal salt granules, which comprises granulating water-soluble polyacrylic acid metal salt powder by a fluidized bed granulation method while spraying an aqueous solution of polyacrylic acid metal salt.