JP2005288294A - Dispersant for electronic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dispersant for an electronic material capable of also reducing a viscosity in slurry having high concentration of a powder of the pulverized electronic material, and further making a change in slurry viscosity due to a change in addition amount of the dispersant and a change in concentration of electronic material slurry small. <P>SOLUTION: The dispersant for the electronic material and a dispersion composition for the electronic material containing the dispersant are each an ammonium salt or an amine salt of a copolymer between acrylic acid or methacrylic acid and an unsaturated dibasic acid, and contain at least one kind of salt selected from the group consisting of a salt of a (metha)acrylic acid-dibasic acid copolymer having a molar ratio of a constitutional monomer unit of (metha)acrylic acid/dibasic acid=50/50 to 92/8 and a weight average molecular weight (Mw) of 25,000 to 80,000. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dispersant for electronic materials that is suitably used when a slurry is obtained by dispersing powder for electronic materials such as pigments in a dispersion medium such as water, and a dispersion composition for electronic materials containing the same.

When dispersing powder for electronic materials such as pigments used for manufacturing electronic parts in an aqueous medium to form a slurry, a polycarboxylate-based dispersant is used. As the above-mentioned slurry has become more functional and finer for electromagnetic / optical member fine ceramics, the powders such as pigments used in electromagnetic / optical member fine ceramics are further refined, and the slurry has a drying efficiency. In order to increase productivity such as improvement, the concentration is further increased. Electromagnetic / optical member fine ceramics, when metal ions such as Na, K, Mg, etc. are mixed, will adversely affect the electromagnetic characteristics. Therefore, chemicals that do not contain metal ions are used. Examples of the agent include those reported in Patent Document 1, Patent Document 2, and Patent Document 3. However, in the dispersants described in these patent documents, for example, when a powder having an average particle size of 0.2 μm or less is reduced in viscosity as a slurry having a solid content of 75% or more, a slight change in the amount of dispersant added or electronic material slurry Due to the change in the concentration, the change in the slurry viscosity is remarkably large. Therefore, it has been pointed out that the workability is deteriorated, for example, when the sheet is formed in a subsequent process such as sheet forming, the sheet is uneven and not uniform. Moreover, although there exists a method of adding a dispersing agent during slurry manufacture in order to improve workability, it has not reached a satisfactory level.
JP 59-22639 A JP 61-101449 A Japanese Patent Laid-Open No. 03-279251

  The problem of the present invention is that it is possible to reduce the viscosity even in a high-concentration slurry of atomized powder for electronic materials, and further, the change in slurry viscosity due to the change in the amount of dispersant added or the concentration change in the electronic material slurry. An object of the present invention is to provide a dispersing agent for electronic materials which can be reduced in size and a dispersing composition for electronic materials containing the same.

  The present invention is an ammonium salt or amine salt of a copolymer of acrylic acid or methacrylic acid and an unsaturated dibasic acid (hereinafter referred to as a salt of a (meth) acrylic acid-unsaturated dibasic acid copolymer). The molar ratio of the constituent monomer units is (meth) acrylic acid / unsaturated dibasic acid = 50/50 to 92/8, and the weight average molecular weight (Mw) is 25,000 to 80,000. Disclosed are a dispersant for electronic materials containing at least one selected from the group consisting of salts of basic acid copolymers, and a dispersion composition for electronic materials containing this dispersant.

  The dispersant for electronic materials of the present invention can reduce the viscosity even in a high-concentration slurry of finely divided powder for electronic materials, compared to conventional dispersants for electronic materials. It is possible to reduce the change in slurry viscosity due to the change in the amount or the change in the concentration of the electronic material slurry.

  The reason for producing such a remarkably excellent effect is not clear, but the viscosity of a high-concentration slurry of finely divided powder is reduced to a substantially constant low viscosity without being affected by the amount of dispersant added. In terms of retention, both the adsorption power of the dispersant to the powder such as pigments used in electromagnetic and optical member fine ceramics and the repulsive force (electrostatic and / or steric) due to the dispersant adsorbed on the powder are both It is thought to be based on the superiority.

  The salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer of the present invention reduces the viscosity of a high-concentration slurry of finely divided powder, and is almost constant without being affected by the amount of dispersant added. From the viewpoint of maintaining the viscosity, the molar ratio of the constituent monomer units is (meth) acrylic acid / unsaturated dibasic acid = 50/50 to 92/8, and the weight average molecular weight (Mw) is 25,000 to 80,000.

From the above viewpoint, the (meth) acrylic acid / unsaturated dibasic acid (molar ratio) is preferably 70/30 to 90/10, and more preferably 80/20 to 87/13. Moreover, 25000-60000 are preferable and, as for a weight average molecular weight (Mw), 40000-50000 are more preferable.
Here, the weight average molecular weight (Mw) is a value measured by the measuring method described in Examples.

  As the unsaturated dibasic acid constituting the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer of the present invention, maleic anhydride, maleic acid, itaconic acid, fumaric acid and the like can be used. Of these, maleic anhydride and maleic acid are preferred.

  The salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer of the present invention is an ammonium salt or an amine salt. As the amine salt, primary, secondary or tertiary alkylamine salt or alkanolamine salt, specifically, monoalkyl (alkyl group having 1 to 3 carbon atoms) amine, dialkyl (alkyl group having 1 to 3 carbon atoms). ) Amine, trialkyl (alkyl group having 1 to 3 carbon atoms) amine, monoalkanol (alkanol having 1 to 3 carbon atoms) amine, dialkanol (alkanol having 1 to 3 carbon atoms) amine, trialkanol (alkanol carbon number) 1-3) Salts such as amines may be mentioned. Of these, ammonium salts are preferred.

  The degree of neutralization or alkali excess of the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer of the present invention is not particularly defined, but from the viewpoint of the decomposition resistance of the powder component and the odor resistance, Usually, it is 50 to 120%, preferably 60 to 110%, and more preferably 75 to 105%.

  The degree of neutralization or the excess of alkali means [A (equivalent of free base capable of constituting a salt + equivalent of acid group constituting a salt) / B (free acid group capable of constituting a salt). Equivalent + equivalent of acid group constituting the salt)] × 100 (%). When A / B is 1 or less, the degree of neutralization is expressed, and when A / B = 1, the degree of neutralization is 100%. A / B greater than 1 is expressed as alkali excess and shows a value greater than 100%.

  Further, the pH of the aqueous solution of the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer is preferably 5 to 9 from the viewpoint of the decomposition resistance of the powder component and the odor resistance, and 5.5 to 5.5. 8.5 is more preferable, and 6 to 8 is particularly preferable.

  The content of the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer in the dispersant of the present invention is preferably 97 to 100% by weight in a category in which a high-concentration slurry of powder can be reduced in viscosity. 98 to 100% by weight is more preferable, and 99 to 100% by weight is particularly preferable. In addition to this, unreacted acrylic acid, methacrylic acid, unsaturated dibasic acid and the like may be contained.

  Although the manufacturing method of the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer of this invention is not specifically limited, For example, it can manufacture by the method shown below.

  An unsaturated dibasic acid and ion-exchanged water are charged into a reaction vessel so that the concentration of the unsaturated dibasic acid is 48% by weight or more, heated to 55 ° C., and then an aqueous ammonia solution is charged. Next, after heating to about 100 ° C., at this temperature, acrylic acid or methacrylic acid is added so that the (meth) acrylic acid / unsaturated dibasic acid (molar ratio) is 50/50 to 92/8. Aqueous hydrogen peroxide solution was added dropwise over 3 to 5 hours so that the hydrogen peroxide was 30 to 60 mol% with respect to the total charged moles of (meth) acrylic acid and unsaturated dibasic acid, and polymerization reaction was performed. I do. After completion of dropping, the mixture is aged at 100 ° C. for 5 to 10 hours. After completion of the reaction, the reaction solution is cooled to about 40 ° C., and an aqueous ammonia solution is added so that the pH is around 7. Thus, an ammonium salt of a (meth) acrylic acid-unsaturated dibasic acid copolymer is obtained.

  The dispersant of the present invention has a dispersant addition amount of 0 with respect to 100 parts by weight of the powder for electronic materials, from the viewpoint that the powder slurry maintains a substantially constant low viscosity without being affected by the dispersant addition amount. . When the viscosity is changed to 2 parts by weight, 0.5 part by weight, 1 part by weight, 2 parts by weight and 4 parts by weight, the B content (25 ° C.) of the slurry having a powder content of 50% by weight or more in the slurry It is preferable that the value satisfies the range of M × (1 ± 0.2) mPa · s (where M represents an average viscosity value of B viscosity defined by the following formula).

M = [total value of B viscosity (25 ° C.) of the slurry measured with the added amount of each dispersant when changed in the range of 0.2 to 4 parts by weight (100 parts by weight of the powder for electronic materials) / 5 (number of change points of addition amount)]
That is, for example, the amount of the dispersant added is changed to 0.2 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, and 4 parts by weight (100 parts by weight of the powder for electronic materials). A slurry is prepared, each B viscosity is measured at 25 degreeC, and M which is the average viscosity value is calculated | required. For example, when the average viscosity value M is assumed to be 100 mPa · s, the values of the B viscosity of the slurry tested at each dispersant addition amount at that time are all within the range of 100 × (1 ± 0.2), that is, 80 to It means a value of 120 mPa · s.
The B viscosity is measured by the method described in Example 1.

  Examples of the powder for electronic materials to be used in the present invention include calcium carbonate, calcium phosphate, zinc phosphate, clay, bentonite, satin white, zinc white, bengara, ferrite, titanium oxide, alumina, magnesium oxide, talc, white carbon, Examples thereof include cement, gypsum, carbon black, titanate, and silicate. Among these powders, powders used for electromagnetic / optical member fine ceramics are preferable, and titanates such as barium titanate and alumina are more preferable.

  Fine ceramics are basically composed of an inorganic compound, and are produced by a high-temperature reaction at 1000 ° C. or higher using a mineral as a raw material. Among them, the electromagnetic / optical member fine ceramics include, for example, IC packages, wiring boards, insulators, sensors, electrodes, magnetic bodies, semiconductors, capacitors, optical fibers, and the like.

  The dispersion composition for electronic materials of the present invention can be obtained by dispersing the powder for electronic materials, the raw ore of the powder for electronic materials, or coarse particles in an aqueous medium using the dispersant of the present invention. it can. Examples of the aqueous medium include water or a mixed solution of water and a water-soluble organic solvent such as ethyl alcohol or ethylene glycol, preferably water.

  The content of the powder in the electronic material dispersion composition is not particularly defined, but is preferably 50% by weight or more, more preferably 50 to 85% by weight, from the viewpoint of improving the drying efficiency and increasing the productivity. -85 wt% is particularly preferred. Further, the content of the dispersant of the present invention in the electronic material dispersion composition is not particularly limited as long as it does not interfere with the slurry of the electronic material powder, but 100 parts by weight of the electronic material powder On the other hand, it is preferably 0.2 parts by weight or more, more preferably 0.2 to 6 parts by weight, and particularly preferably 0.5 to 5 parts by weight.

  As a method for obtaining a dispersion composition for an electronic material using the dispersant of the present invention, a usual slurrying method is used. For example, a method in which the electronic material powder is added to an aqueous solution in which the dispersant is dissolved and stirred and mixed, a method in which water and a dispersant are added to the electronic material powder, and the mixture is stirred and mixed. As a method of stirring and mixing, for example, a generally used stirring device such as a high-speed disper, a homomixer, or a ball mill can be used.

  In addition, when slurrying the ore or coarse particles of the powder for electronic materials at the same time as pulverization, a method of adding water and a dispersant to the ore or coarse particles of the powder for electronic materials and slurrying at the same time as pulverization Etc. A generally used wet pulverizer such as a bead mill can be used as a method of slurrying simultaneously with pulverization.

In the following examples, the weight average molecular weight of the dispersant was measured by GPC (gel permeation chromatography) under the following conditions.
Column: TSK PWXL + G4000PWXL + G2500PWXL (both manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Detector: RI or UV (210 nm)
Eluent: 0.2 mol / L phosphate buffer / acetonitrile (9/1)
Flow rate: 1.0 mL / min
Injection volume: 0.1 mL
Standard: Polyethylene glycol Production Example 1
A reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was charged with 78.5 g of maleic anhydride and 80.0 g of ion-exchanged water, heated to 55 ° C., and then 28 wt% aqueous ammonia solution. 24.3g was dripped and it was set as the maleic acid ammonium salt aqueous solution. Maleic acid / ammonia = 100/50 (molar ratio). Next, after heating to 100 ° C. under a nitrogen stream, while maintaining this temperature, 360.5 g of an 80 wt% aqueous acrylic acid solution and 153.9 g of a 35 wt% aqueous hydrogen peroxide solution were respectively added from separate dropping funnels to 3.5. The polymerization reaction was carried out dropwise over time. After completion of the dropwise addition, the polymerization reaction was completed by aging at 100 ° C. for 10 hours. After completion of the reaction, the reaction mixture was cooled and neutralized with a 28 wt% aqueous ammonia solution so as to have a pH of 6 to 8 while maintaining about 40 ° C to obtain an ammonium salt of an acrylic acid-maleic acid copolymer. This is referred to as Dispersant 1.

Production Examples 2 to 10
In the same manner as in Production Example 1, a salt of a (meth) acrylic acid-unsaturated dibasic acid copolymer having a monomer composition ratio and a weight average molecular weight shown in Table 1 was produced. These are referred to as dispersants 2 to 10, respectively.

Comparative Production Examples 1-6
The (co) polymer salts having the monomer composition ratio and the weight average molecular weight shown in Table 1 are referred to as comparative dispersants 1 to 6, respectively.

  In the table, MA represents maleic acid, AA represents acrylic acid, MAA represents methacrylic acid, BA represents butyl acrylate, and all of the copolymer salts are ammonium salts.

Example 1
158 g of barium titanate powder having an average particle size of 0.1 μm and a dispersion amount of 0.2 parts by weight of each of the dispersants 1 to 10 or the comparative dispersants 1 to 6 are added to 500 mL of a distiller beaker. Special Kika Kogyo Kogyo Co., Ltd. added 5 parts by weight, 1.0 part by weight, 2.0 parts by weight, 4.0 parts by weight (to 100 parts by weight of barium titanate powder), and ion-exchanged water. The mixture was stirred with a company homodisper (2500 rpm × 2 minutes) to prepare an 80 wt% powder slurry (dispersion composition). Next, this slurry and 2 mm zirconia beads (a ratio of 2 times the weight of the slurry) were charged into a 500 mL wide mouthed polybin, and stirred (150 rpm × 10 hours) with a tabletop pot mill rotary table manufactured by Iuchi Seieido Co., to prepare a slurry. . The B viscosity of the obtained slurry at 25 ° C. was measured at a rotational speed of the rotor of 60 rpm using a B-type viscosity measuring apparatus manufactured by Tokyo Keiki Co., Ltd.

  Table 2 shows the results of the B viscosity, the average viscosity value M, the maximum viscosity value / M, and the minimum viscosity value / M when each dispersant is used.

  A slurry that has a slurry viscosity of 200 mPa · s or less, a maximum viscosity value / M of 1.2 or less, and a minimum viscosity value / M of 0.8 or more is a good dispersant. .

Claims (5)

  Ammonium salt or amine salt of copolymer of acrylic acid or methacrylic acid and unsaturated dibasic acid (hereinafter referred to as salt of (meth) acrylic acid-unsaturated dibasic acid copolymer) (Meth) acrylic acid-unsaturated dibasic acid copolymer having a molar ratio of (meth) acrylic acid / unsaturated dibasic acid = 50/50 to 92/8 and a weight average molecular weight (Mw) of 25,000 to 80,000. A dispersant for an electronic material containing at least one selected from the group consisting of a combined salt.   The dispersant for electronic materials according to claim 1, wherein the unsaturated dibasic acid is at least one selected from maleic anhydride and maleic acid.   The dispersant for electronic materials according to claim 1 or 2, wherein the salt of the (meth) acrylic acid-unsaturated dibasic acid copolymer is an ammonium salt. When 100 parts by weight of the powder for electronic materials is used, the amount of dispersant added is changed to 0.2 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight and 4 parts by weight. The value of B viscosity (25 ° C.) of the slurry having a body content of 50% by weight or more is M × (1 ± 0.2) mPa · s (where M is an average viscosity value of B viscosity defined by the following formula) The dispersant for electronic materials according to any one of claims 1 to 3, which satisfies the requirements in the range of
M = [total value of B viscosity (25 ° C.) of the slurry measured with the added amount of each dispersant when changed in the range of 0.2 to 4 parts by weight (100 parts by weight of the powder for electronic materials) / 5 (number of change points of addition amount)] The dispersion composition for electronic materials containing the dispersing agent in any one of Claims 1-4.