JPS6028818A - Dispersing agent for calcium carbonate - Google Patents

Abstract

PURPOSE:To obtain a titled dispersing agent exhibiting satisfactory dispersibility even to a high-concn. slurry by constituting said agent of acrylic acid and/or methacrylic acid, one kind among maleic acid, fumaric acid, and itaconic acid, and a monomer contg. a phosphate ester group. CONSTITUTION:The agent is constituted of the salt of a copolymer of 40- 99mol% the following component (A), 0-50mol% (B), and 1-10mol% (C). The component (A) consists of >=1 kind of unsaturated monocarboxylic acid selected from acrylic acid and methacrylic acid, the component (B) consists of >=1 kind of unsaturated dicarboxylic acid selected from maleic acid, fumaric acid, and itaconic acid, and the component (C) consists of >=1 kind of a monomer contg. a phosphate ester group having a terminal double bond. The dispersing agent shows a high dispersibility and gives a low viscosity even to a high-concn. slurry with a reduced amt. of addition. The agent also has durable stability, and shows a sufficient dispersing effect even on fine particles having <=1mu particle diameter.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a dispersant for calcium carbonate.

[Prior art]

Calcium carbonate is widely used in the form of an aqueous slurry dispersed in water in various fields such as rubber, synthetic resins, paper, and paints. The aqueous slurry of calcium carbonate used in fields such as λ naturally needs to have good dispersibility and high concentration in order to be a high-quality raw material for products and for ease of handling. In addition, it is required to have low viscosity and excellent stability over time.

The conventional method for producing calcium carbonate slurry involves passing carbon dioxide gas through an aqueous suspension of calcium hydroxide to generate a precipitate, and then filtering the precipitate using a filter press.
A method generally employed is to add an aqueous solution containing a dispersant to the filtered precipitate to form a slurry. in this case,
By adjusting the reaction conditions of calcium hydroxide and carbon dioxide, particles of various sizes and shapes can be obtained.
For example, the particle size is 0.02-0. lOμ! It is possible to adjust the size from extremely fine (2) to relatively large (1 to 3 μm), and the shape can be adjusted from almost cubic
You can even change it to have a spindle shape. Further, the calcium carbonate slurry can be obtained by dispersing a previously obtained powder in water together with a dispersant.

In the above-mentioned calcium carbonate slurry, dispersants used in combination include phosphoric acid sodium salts such as sodium tripolyphosphate and sodium hexametaphosphate, homopolymers of acrylic acid, and copolymers of acrylic acid and maleic anhydride. Polymeric polycarboxylic acid salts, ammonium salts, etc., such as copolymers of acrylic acid and sulfone group-containing monomers (eg, styrene sulfonic acid), have been generally employed.

However, these conventionally used dispersants
The dispersion effect and stability over time are still not satisfactory, and the resulting slurry has high viscosity at high concentrations and poor stability over time. Furthermore, in order to obtain a slurry with a low viscosity, it is necessary to increase the degree of dispersion creation, and it does not show a particular dispersion effect for calcium carbonate particles with an average particle size of 1μI11 or less. Including problems.

〔the purpose〕

The present invention overcomes the drawbacks of conventional calcium carbonate dispersants, shows good dispersibility even in highly concentrated slurries at reduced loadings, and provides low viscosity.
-1 VL with excellent stability and average particle size of 1 μm or more
An object of the present invention is to provide a calcium carbonate dispersant that exhibits a good dispersion effect even for fine particles.

[withered]

The present invention is carbonic acid consisting of a copolymer salt containing 11% of F, nail body component (A): 40 to 99 mol%, (0): 0 to 50 mol%, and (C): 1 to 10 mol%. A dispersant for calcium is provided.

Component [A] At least one unsaturated monocarboxylic acid selected from niacrylic acid and methacrylic acid Component [B]: At least one unsaturated dicarboxylic acid selected from maleic acid, fumaric acid, and itaconic acid. Component [C]: At least one monomer containing a phosphate ester group having a terminal double bond In the polymer dispersant of the present invention, acrylic acid and/or methacrylic acid and a phosphate ester group-containing monomer as an essential component of the copolymer. It contains a monomer and, if necessary, at least one selected from maleic acid, fumaric acid, and itaconic acid. The dispersant of the present invention, which is a salt of a copolymer consisting of such components, has a significantly superior dispersion effect and has significantly improved stability over time compared to conventional ones. .

In the present invention, acrylic acid and/or methacrylic acid used as the unsaturated monocarboxylic acid component [Δ] of the copolymer is 40 to 99 mol%, or 52 to 95 mol%.
One or two or three selected from maleic acid, fumaric acid and itaconic acid used as the saturated dicarboxylic acid component [0] is 0 to 50 mol%, preferably 4 40 mol%, and the phosphoric acid ester group-containing monomer having a 4L terminal double bond used as component (C) is 1 to 10 mol%, preferably 1 to 8 mol%. The dispersant of the present invention can be easily obtained by copolymerizing these components by a conventional method.

In this case, the carboxyl groups contained in components [A) and [11] can exist in the form of alkali metal salts, ammonia-11 salts, organic amine salts, etc. in addition to the carboxyl groups of 3IttFllt during the reaction. Also component (C)
The phosphoric acid ester group can likewise be present in the form of a salt during the reaction.

As the phosphate group-containing monomer having a terminal double bond used as the copolymer component [c] in the present invention, conventionally known monomers can be used, such as those represented by the following general formulas (1) and (II). Those shown are preferably adopted.

In the above formula, R is a hydrogen atom or a methyl group, amine, triethanolamine, dimethylamine, etc.), and n is an integer of 2 to 4.

Such a monomer containing a phosphoric acid ester group having a terminal double bond can be obtained by introducing a phosphoric acid group into a hydroxyalkyl ester of an unsaturated monocarboxylic acid having a double bond such as acrylic acid or methacrylic acid. Preferred specific examples thereof include hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate,
■-Talolomethyl-2-hydroxyethyl acrylate-1
Examples include phosphoric acid esters such as -11-chloromethyl-2-hydroxyethylmethacrylate-1-. As this phosphoric acid ester, a monoester is preferable, but a part thereof may include a diester or a 1-diester. The proportion of this phosphate group-containing monomer affects the effect of the dispersant, and it is best to select it in the range of 0.1 to 10 mol% based on the total monomer components. The dispersion effect is significantly reduced.

The salt of the copolymer used as a dispersant in the present invention generally has an average molecular weight of 500 to 50,000, and has an average molecular weight of 10,000 to 20,000. In addition, as the polymer salt, alkali metal salts and ammonium salts such as sodium salts and potassium-11 salts are preferable, but those in which a part of them is substituted with alkaline earth metal salts such as calcium salts are preferred. In addition, unneutralized portions may remain, and it is sufficient that the entire copolymer salt is water-soluble.The method for synthesizing the copolymer salt according to the present invention is particularly limited. Any method may be used as long as it provides a salt of the copolymer as described above.

In addition, in the copolymer of the present invention, it is also possible to add other monomers as necessary, as long as they do not particularly impair the aspect 1 of the present invention. For example, an alkyl group having 1 to 3 carbon atoms may be added. A vinyl monomer such as an acrylic ester or methacrylic ester, acrylamide, or acid-resistant vinyl, or a monomer having a sulfonic acid group such as styrene sulfonic acid is substituted for a part of the unsaturated monocarboxylic acid component (A). You can also.

The dispersant of the present invention exhibits an excellent effect on the dispersion of calcium carbonate 11 in water, and provides a highly concentrated slurry of calcium carbonate with excellent dispersibility and stability over time and reduced viscosity. The dispersant of the present invention contains 0.1
~5.0% by weight, preferably 0.3~2.0% per 100 parts by weight of calcium carbonate! in: Used within the range of parts.

〔effect〕

The dispersant of the present invention exhibits a good dispersion effect when added in a small amount to calcium carbonate slurry with a wide range of concentrations, from a low concentration of 50% by weight or less to a high concentration of 70% by weight or more, and has a low viscosity. Gives a slurry that is thick and has good stability over time. Further, the dispersant of the present invention exhibits an excellent dispersion effect even for fine calcium carbonate having an average particle diameter of 1 μm or less.

In addition, the dispersant of the present invention shows a particularly excellent dispersion effect when chopped into calcium carbonate (precipitated calcicarbonate), but it can also be used with similar solid fine powders such as clay, kaolin, titanium oxide, hydroxide, etc. It also shows a good dispersion effect when dispersing inorganic pigments such as aluminum and satin white in water.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A dispersant aqueous solution shown in Table 1 below was coated with a particle size of 1μ
■ Add 60 parts by weight of precipitated calcium carbonate containing 65% by weight or more of particles of 1 or less, and mix this with a homomixer (TK
Stir and disperse for 10 minutes depending on the solid content concentration (type).
A heavy weight calcium carbonate/water slurry was obtained. In this case, the amount of dispersant used is 1% by weight based on calcium carbonate.
It was used at a ratio of

Next, the viscosity of this slurry was measured using a UL viscometer (
Measurement was carried out using a Tokyo Keiki Kaisha) under the conditions of 25°C, 60 rpm, and 1 minute value. The results are shown in the table below.

In addition, each code|symbol shown in the following Table-1 - Table-3 means the following.

[^-1]: Acrylic acid component (A-2): Methacrylic acid component (B-13: Maleic acid component [11-2]: Fumaric acid component (B-3): Itaconic acid component (C-1): (C-2): Also, the copolymer weight used as a dispersant is yz -4"
JL is also a 1-lium salt, and its molecular weight is
- Determined by migration chromatography.

As is clear from the results shown in Table 1, by adding the phosphate ester component to the copolymer component, the dispersibility and oral stability of the copolymer salt were significantly improved, and the resulting J
It can be seen that the slurry is of high quality.

Example 2 An experiment was conducted in the same manner as in Example 1, except that the amount of dispersant added was varied. The results are shown in the table below.

As is clear from the results shown in Table 2, when the dispersant of the present invention was used (Experiment N (11-6)) and when the dispersant for comparison was used (Experiment +407-13), In comparison, it can be seen that a slurry with low viscosity and excellent oral stability can be obtained with a reduced amount added.

Example 3 In Example 1, the concentration of calcium carbonate in the slurry was increased by 70% (the amount of dispersant added was 1% carbonate to lucium).
The experiment was conducted in the same manner except that the amount was changed to (% by weight). The results are not shown in the following table.6 From the results shown in Table 3, the dispersants of the present invention (NL11 to
3) shows significantly superior dispersibility and oral stability compared to the comparative product even in a slurry with a high concentration of 70 weight, as in the case of the calcium carbonate/water slurry of 60 weight nail part. I understand.

Patent Applicant Lion Co., Ltd. Agent Patent Attorney Toshiaki Ikeura Proceeding Amendment September 1981 2 IJ Patent Application No. 13816 of 1988] 2. Name of Invention Dispersant for Calcium Carbonate 3. Case of Person Making Amendment Patent applicant address: Honjo IJ “I=+ 3-7, Sumida-ku, Tokyo”
Name (676) Lion Co., Ltd. Representative Atsushi Kobayashi 4, Agent 〒151 7, Subject of amendment Structure of detailed explanation of the invention in the specification 8, Contents of amendment The following amendments will be made in the specification of this application.

(1) [0,1~1O mol%” in page 9, line 11, r
Corrected to 1-10 mol%.

(2) Page 9, line 16 r 1ooooo~2001)O
First, correct J to 1'3000~20000J.

Claims (5)

[Claims] (1) The following monomer components [43,840 to 99 mol%, (B
): 0 to 50 mol % and [C]: 1 to 10 mol % of a copolymer salt. Component [A] At least one component of unsaturated monocarboxylic acid selected from niacrylic acid and methacrylic acid [Ingredient]: At least one component of unsaturated dicarboxylic acid selected from maleic acid, fumaric acid, and itaconic acid [C]: At least one type of phosphate group-containing monomer having a terminal double bond (2) A monomer containing a phosphate ester group having a terminal double bond has the general formula (wherein, R is a hydrogen atom or a methyl group, M is a hydrogen ion,
The dispersant according to claim 1, which is an alkali metal ion, an ammonium ion, or an organic ammonium ion, and n is an integer of 2 to 4. (3) A monomer containing a phosphate ester group having a terminal double bond has the general formula: (wherein, R is a hydrogen atom or a methyl group, The dispersant according to claim 1, which is an ammonium ion. (4) The dispersant according to any one of claims 1 to 3, wherein the copolymer has an average molecular weight of 500 to 501 JOO. (5) The dispersant according to any one of claims 1 to 4, wherein the salt of the copolymer is an alkali metal salt or an ammonium salt.