Dispersion agent and slurry composition for fine particles

Abstract

The present invention relates to a slurry composition which can maintain excellent dispersion stability of a powder even if a binder is added. The means for solving the technical problem is a dispersant for fine particles formed from a polyether ester compound or a salt thereof, the polyether ester compound being an ester reactant of component (a1) and component (a2) and having an acid value of 85 to 220 mgKOH / g, component (a1): a polyether compound of formula (1) HO-(AO) m -H ··· (1) AO is an oxyalkylene group having 2 to 4 carbon atoms, the oxyethylene group accounts for 20% or more by mass of AO, m is 2 to 30, component (a2): a polybasic acid having 2 or 3 carboxyl groups or an acid anhydride thereof having 2 to 9 carbon atoms.

Description

Technical Field

[0001] This invention relates to a particulate dispersant and a slurry composition for dispersing organic or inorganic powders or other dispersions in a solvent. More specifically, it relates to a particulate dispersant that maintains excellent dispersion stability even with the addition of a binder, and a slurry composition using the particulate dispersant. Background Technology

[0002] Electronic components such as multilayer ceramic capacitors (MLCCs) or multilayer chip inductors are mainly manufactured by a process of laminating a printed circuit board (green sheet) formed of ceramics such as barium titanate and ferrite, and a binder resin. Furthermore, this printed circuit board is manufactured by: mixing ceramic particles, solvents, dispersants, etc., and crushing them using a bead mill or ball mill; adding polyvinyl butyral resin or acrylic resin; and further adding plasticizers, thereby preparing a slurry composition; and coating this prepared slurry composition onto a PET film or similar material and drying it.

[0003] In recent years, with the miniaturization and high performance of electronic devices, there is a need for miniaturization and high capacity of MLCCs. To achieve miniaturization and high capacity, the ceramic printed circuit board and conductive layer, which are its constituent components, are thin-film / multilayered. Furthermore, to obtain high-quality thin films, ceramic or metal powders used as raw materials for the paste composition are micronized, and a high molecular weight resin that provides strength even in thin films is used as a binder.

[0004] On the other hand, in the past, dispersants were used to efficiently crush ceramic or metal powders in solvents and obtain dispersion stability after crushing. For example, Patent Document 1 proposed an esterification of polyoxyethylene monophenyl ether and cyclic carboxylic acid. However, when the powder is micronized as described above, the increased cohesion between particles leads to the aforementioned problems of decreased dispersibility in the initial stage of crushing or decreased dispersion stability over time.

[0005] To address this problem, a dispersant has been proposed to improve the initial dispersibility or dispersion stability of particles with a particle size of less than 1 μm. Patent Document 2 shows a specific polyoxyalkylene ether ester with trimellitic acid.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2007-144402

[0009] Patent Document 2: Japanese Patent Application Publication No. 2016-147216 Summary of the Invention

[0010] The technical problem to be solved by the present invention

[0011] However, recently, with the advancement of raw material powder micronization, the demand for dispersant performance in slurry compositions has been increasing. In particular, when the powder particle size is small, the dispersibility or dispersion stability obtained in the solvent can significantly decrease when adding a binder component as a polymeric resin to the slurry. If the dispersion stability of the slurry composition decreases, it becomes difficult to obtain high-quality printed circuit boards as thin films due to the inability to uniformly coat the slurry.

[0012] The technical problem of the present invention is to solve the above-mentioned technical problem. In detail, the technical problem of the present invention is to provide a slurry composition that not only maintains excellent powder dispersion stability in a solvent, but also maintains excellent powder dispersion stability even when a binder is added.

[0013] Technical means to solve technical problems

[0014] In order to solve the above-mentioned technical problems, the inventors of this application conducted a careful study and found that the above-mentioned technical problems can be solved by using a particulate dispersant formed by a polyether ester compound or its neutral salt, wherein the polyether ester compound is formed by a polyether with a specific structure and a polybasic acid.

[0015] That is, the present invention is as described in [1] and [2] below.

[0016] [1] A particulate dispersant, characterized in that the particulate dispersant is formed from a polyether ester compound or its neutralized salt, wherein the polyether ester compound is an ester reaction product of the following components (a1) and (a2) and has an acid value of 85-220 mg KOH / g.

[0017] Component (a1): The polyether compound represented by formula (1) below,

[0018] HO-(AO) m -H····(1)

[0019] In formula (1), AO is an oxidized alkenyl group with 2 to 4 carbon atoms, the oxyethylene group accounts for more than 20% by mass of the oxidized alkenyl AO, and m is the average number of moles of addition of the oxidized alkenyl AO, where m is 2 to 30.

[0020] Component (a2): A polybasic acid or its anhydride having 2 to 9 carbon atoms and 2 or 3 carboxyl groups.

[0021] [2] A slurry composition, characterized in that the slurry composition contains 0.01 to 6% by mass of component (A), 1 to 10% by mass of component (B), 10 to 60% by mass of component (C), and the balance component (D).

[0022] Component (A): [1] the microparticle dispersant described above.

[0023] Ingredient (B): Polyvinyl butyral,

[0024] Composition (C): Powder with an average particle size of less than 200 nm.

[0025] Component (D): Solvent.

[0026] Invention Effects

[0027] According to the present invention, not only can the dispersion stability of powder in solvent be maintained, but also excellent dispersion stability can be maintained even when a binder is incorporated. Detailed Implementation

[0028] The particulate dispersant and slurry composition of the present invention will be described below.

[0029] (Dispersant for microparticles)

[0030] The particulate dispersant of the present invention is formed from a polyether ester compound or its neutralized salt, wherein the polyether ester compound is characterized in that it is formed from an ester reactant of component (a1) and component (a2) and has an acid value of 85 to 220 mg KOH / g.

[0031] (ingredient (a1))

[0032] The component (a1) in this invention is the polyether compound represented by formula (1).

[0033] HO-(AO) m -H····(1)

[0034] In formula (1), AO is an oxidized alkenyl group with 2 to 4 carbon atoms, which can be obtained by addition polymerization of ethylene oxide, propylene oxide, and butane oxide. Its addition form can be random or block.

[0035] When the total mass of oxidized alkenyl AO is set to 100% by mass, the vinyl oxy group accounts for 20% by mass or more, preferably 35% by mass or more, and even more preferably 50% by mass or more. When the mass of vinyl oxy group is less than 20% by mass, it is difficult to obtain compatibility with alcohol solvents or polyvinyl butyral resins, and therefore the dispersion stability of the slurry will decrease.

[0036] When the total mass of oxidized alkenyl AO is set to 100% by mass, the ratio of oxyethylene can be 100% by mass.

[0037] In formula (1), m is the average number of moles of oxidized alkenyl groups represented by AO, and m is 2 to 30. If m is less than 2, it is difficult to obtain dispersion stability. If m is greater than 30, the powder particles tend to agglomerate, and the viscosity in the initial stage of dispersion becomes difficult to decrease. From the perspective of the present invention, m is preferably 3 or more, and more preferably 4 or more. In addition, m is preferably 20 or less, and more preferably 15 or less.

[0038] Furthermore, the molecular weight of the polyether compound represented by formula (1) is preferably 100 to 1500, more preferably 100 to 1000, and even more preferably 100 to 600.

[0039] (Component (a2))

[0040] The component (a2) in this invention is a polybasic acid or its anhydride having 2 to 9 carbon atoms and 2 or 3 carboxyl groups. The polybasic acid is particularly preferably composed of 2 to 6 carbon atoms. Examples of polybasic acids include succinic acid, maleic acid, adipic acid, phthalic acid, and trimellitic acid. From the perspective of easy reaction with alcohols, anhydrides are preferred, including succinic anhydride, maleic anhydride, phthalic anhydride, and trimellitic anhydride, with succinic anhydride being particularly preferred.

[0041] The polyether ester compound of the present invention is an ester reactant obtained by esterification of component (a1) with component (a2). This reaction can be carried out in a solvent-free environment or using a suitable dehydrating organic solvent. The solvent used in the reaction can be removed after the reaction by distillation or other operations, or it can be used directly as part of the product. The reaction temperature is preferably 60–180°C, more preferably 70–160°C, and particularly preferably 80–140°C.

[0042] The preferred reaction ratio of component (a1) to component (a2) is a molar ratio of component (a1) / component (a2) of 2 / 1 to 1 / 2.

[0043] Furthermore, the acid value of the polyether ester compound of the present invention is 85–220 mg KOH / g, preferably 100–220 mg KOH / g, more preferably 120–220 mg KOH / g, and even more preferably 140–200 mg KOH / g. If the acid value is lower than 85 mg KOH / g, it lacks adsorption capacity for the powder and it is difficult to obtain dispersion stability.

[0044] The molecular weight of this polyether ester compound is preferably 200–1600, more preferably 200–1100, and even more preferably 200–700. The molecular weight can be determined by conventional methods, such as gel permeation chromatography using THF solvent.

[0045] The polyether ester compounds of the present invention can be neutralized using amines. Examples of amines include alkylamines such as ammonia, monomethylamine, dimethylamine, and ethylamine, or alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine. One or more of these amines can be used.

[0046] (Slurry composition)

[0047] The slurry composition of the present invention contains 0.01 to 6% by mass of component (A), 1 to 10% by mass of component (B), 10 to 60% by mass of component (C), and the balance component (D).

[0048] Component (A): The above-mentioned particulate dispersant,

[0049] Ingredient (B): Polyvinyl butyral,

[0050] Composition (C): Organic or inorganic powders with an average particle size of less than 200 nm.

[0051] Component (D): Solvent.

[0052] The content of component (A) (dispersant for particulate matter) in the slurry composition is 0.01 to 6% by mass. The content of component (A) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and particularly preferably 0.3% by mass or more. Furthermore, the content of component (A) is more preferably 5% by mass or less, and particularly preferably 4% by mass or less.

[0053] The total content of components (A), (B), (C), and (D) is set to 100 by mass.

[0054] In addition, microparticles refer to organic or inorganic powders with an average particle size of less than 200 nm (C).

[0055] As component (B) (binder) in the slurry composition, polyvinyl butyral resin, acrylic resin, ethyl cellulose resin, etc. can be used, with polyvinyl butyral resin being preferred as it is easy to obtain the strength of the printed circuit board after thin film formation.

[0056] In particular, from the perspective of easily obtaining the strength of the thin-film printed circuit board, it is preferable to combine the particulate dispersant of the present invention with polyvinyl butyral having a weight-average molecular weight of 60,000 or more, and more preferably with polyvinyl butyral having a weight-average molecular weight of 100,000 or more. Furthermore, from the perspective of solvent solubility, it is preferable that the weight-average molecular weight of the polyvinyl butyral resin is 1,000,000 or less, and more preferably 500,000 or less.

[0057] In addition, the weight-average molecular weight of the present invention was determined using gel permeation chromatography under the following conditions.

[0058] Device: TOSOH CORPORATION HLC-8320GPC

[0059] Columns: SHODEX KF-804L (8mm inner diameter × 30cm length) manufactured by Showa Denko KK, 3 columns

[0060] Eluent: Tetrahydrofuran

[0061] Flow rate: 1.0 mL / min

[0062] Detector: Differential refractometer (RI)

[0063] Temperature: 40℃

[0064] Standard: Polyethylene glycol

[0065] Sample: Inject 100 μL of a THF solution containing 0.1 wt% active ingredient.

[0066] The content of component (B) in the slurry composition is set to 1-10% by mass, preferably 1-8% by mass, and more preferably 2-6% by mass.

[0067] The component (C) (organic powder and inorganic powder) is not particularly limited as long as it is a component that is usually used for slurry preparation, and ceramic powder, which is widely used as a raw material for electronic components manufactured by lamination process, is particularly preferred.

[0068] As ceramic powders, various powders can be listed, including silicate minerals, other silicate compounds, carbonate compounds, sulfate compounds, hydroxides, oxides, nitrides, carbides, titanate compounds, etc. Examples include kaolin, clay, talc, mica, bentonite, dolomite, calcium silicate, aluminum silicate, magnesium silicate, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, aluminum sulfate, aluminum hydroxide, iron hydroxide, zirconium oxide, magnesium oxide, aluminum oxide, titanium oxide, iron oxide, zinc oxide, antimony trioxide, indium oxide, indium tin oxide, silicon carbide, tungsten carbide, aluminum nitride, silicon nitride, boron nitride, barium titanate, calcium titanate, strontium titanate, carbon black, glass fiber, carbon fiber, carbon nanofibers, and carbon nanotubes (single-walled nanotubes, double-walled nanotubes, multi-walled nanotubes), etc.

[0069] As ceramic powder, powders of oxides such as zirconium oxide, magnesium oxide, aluminum oxide, iron oxide, zinc oxide, and indium tin oxide, as well as powders of titanate compounds such as barium titanate, calcium titanate, and strontium titanate, are particularly preferred.

[0070] With the thin-film development of printed circuit boards, there is a trend towards using ceramic powders with smaller average particle sizes. From this perspective, it is preferable to combine them with ceramic powders with an average particle size of 200 nm or less, more preferably with ceramic powders with an average particle size of 100 nm or less, and even more preferably with ceramic powders with an average particle size of 50 nm or less. Furthermore, the average particle size of the powder can be measured using SEM (scanning electron microscopy).

[0071] The content of component (C) is set to 10-60% by mass, preferably 20-60% by mass, and more preferably 20-50% by mass.

[0072] As component D (solvent), a solvent compatible with the dispersant or binder can be used. Examples of such solvents include alcohols, ethers, ketones, and aromatics. In particular, from the perspective of compatibility with polyvinyl butyral, ethanol, toluene, or mixtures thereof are preferred.

[0073] In this composition, component (D) (solvent) is the balance when the total content of components (A), (B), (C) and (D) is set to 100% by mass.

[0074] In addition to the aforementioned admixtures, the slurry composition of the present invention and the ceramic printed circuit board composition utilizing the slurry composition may contain other ceramic additives, plasticizers, antistatic agents, etc., as general components. For example, common plasticizers include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, tributyl acetylacetonate, etc.

[0075] Furthermore, when the total amount of components (A), (B), (C), and (D) is set to 100% by mass, it is preferable to set the ratio of these added components to 7% by mass or less, and more preferably to 5% by mass or less.

[0076] Example

[0077] The present invention will be further described in detail below by way of examples, but the present invention is not limited to these examples in any way.

[0078] (Preparation Example)

[0079] (Example 1)

[0080] Polyethylene glycol (m = 5, 400 g, 2 mol) and succinic anhydride (200 g, 2 mol) were added to a 1 L four-necked flask, and the mixture was stirred until homogeneous while the temperature was raised to 90 °C. After reaching this temperature for 7 hours, the mixture was cooled to stop the reaction. The compound obtained in Example 1 had an acid value of 185 and a weight-average molecular weight of 303 as determined by GPC.

[0081] (Example 2)

[0082] Using the same raw materials and the same amount added as in Example 1, the reaction was carried out at 110°C for 7 hours. The resulting compound had an acid value of 130 and a weight-average molecular weight of 432 as determined by GPC.

[0083] (Example 3)

[0084] Using the same raw materials and the same amount added as in Example 1, the reaction was carried out at 110°C for 12 hours. The resulting compound had an acid value of 112 and a weight-average molecular weight of 501 as determined by GPC.

[0085] (Example 4)

[0086] Polyethylene glycol (m = 10, 402 g, 1 mol) and succinic anhydride (200 g, 2 mol) were added to a 1 L four-necked flask. The mixture was stirred until homogeneous while the temperature was raised to 90 °C. After reaching this temperature for 7 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 185 and a weight-average molecular weight of 636 as determined by GPC.

[0087] (Example 5)

[0088] An ethylene oxide-propylene oxide copolymer (m=6, EO to PO molar ratio of 1:1, 300 g, 1 mol) and trimellitic anhydride (162 g, 0.77 mol) were added to a 1 L four-necked flask. The mixture was stirred until homogeneous while the temperature was raised to 120 °C. After reaching this temperature for 7 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 153 and a weight-average molecular weight of 660 as determined by GPC.

[0089] (Comparative Example 1)

[0090] The same raw materials and addition ratios as in Example 1 were used. However, unlike Example 1, the mixture was stirred until homogeneous while being heated to 150°C. After reaching this temperature for 5 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 80 and a weight-average molecular weight of 701 as determined by GPC.

[0091] (Comparative Example 2)

[0092] Propylene glycol (m = 5, 560 g, 2 mol) and succinic anhydride (200 g, 2 mol) were added to a 1 L four-necked flask, and the mixture was stirred until homogeneous while the temperature was raised to 90 °C. After reaching this temperature for 7 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 141 and a weight-average molecular weight of 395 as determined by GPC.

[0093] (Comparative Example 3)

[0094] Polyethylene glycol (m = 25, 500 g, 0.5 mol) and succinic anhydride (50 g, 0.5 mol) were added to a 1 L four-necked flask, and the mixture was stirred until homogeneous while heating to 110 °C. After reaching this temperature for 8 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 50 and a weight-average molecular weight of 1122 as determined by GPC.

[0095] (Comparative Example 4)

[0096] Polyethylene glycol (m = 2, 186 g, 3 mol) and succinic anhydride (300 g, 3 mol) were added to a 1 L four-necked flask, and the mixture was stirred until homogeneous while the temperature was raised to 90 °C. After reaching this temperature for 5 hours, the mixture was cooled to stop the reaction. The resulting compound had an acid value of 290 and a weight-average molecular weight of 193 as determined by GPC.

[0097] (Compare Examples 5 and 6)

[0098] The compound of Comparative Example 5 was set as a copolymer of maleic anhydride and allyl polyether (weight average molecular weight of 10,000), and the compound of Comparative Example 6 was set as isodec-EO (oxyvinyl) 3 mol-PO (oxypropylene) 8 mol-trimethicone monoester.

[0099] (Preparation method of slurry composition)

[0100] The compounds synthesized in Examples 1, 3, 5, and Comparative Examples 2, 5 were used as dispersants to prepare slurry compositions 1-1 to 1-5 and 2-1 to 2-5 in the following manner.

[0101] 100.0 g of barium titanate powder (average particle size: 0.1 μm, determined by electron microscopy using SEM), 40 g of toluene / ethanol mixed solvent (weight ratio 1 / 1), and 2 g of each dispersant were weighed into a 250 mL poly bottle. The mixture was dispersed in a ball mill for 8 hours using 2 mm zirconia beads to obtain slurry compositions 1-1 to 1-5.

[0102] Further, 143g of a polyvinyl butyral resin (weight average molecular weight 200,000) solution (a solution prepared by dissolving 10g of resin in 133g of a toluene / ethanol mixed solvent) and 4g of dioctyl phthalate were added to each slurry composition, and the mixture was dispersed in a ball mill for 10 hours using 2mm zirconia beads to obtain slurry compositions 2-1 to 2-5. The proportions of each raw material in the slurry are shown in Table 2.

[0103] (Stability evaluation of the slurry)

[0104] The viscosity of various slurry compositions was measured immediately after dispersion and 24 hours after dispersion.

[0105] In the viscosity determination, a dynamic viscoelastic apparatus (Paar Physica MCR-300, manufactured by Anton Paar) was used to measure the cut viscosity at a temperature of 20°C and a cutting speed of 0.1–100 (1 / s). The cut viscosity at a cutting speed of 1 (1 / s) is shown in Tables 3 and 5.

[0106] In addition, as an indicator of stability, the viscosity increase ratio (viscosity after 24 hours / viscosity after dispersion) was measured and evaluated according to the following criteria.

[0107]

[0108]

[0109]

[0110]

[0111] As shown in Table 3, the slurry compositions 1-1, 1-2, 1-3, 2-1, 2-2, and 2-3 using the dispersants of Examples 1, 3, and 5 of this invention exhibit high viscosity stability after dispersion, regardless of the presence or absence of a binder.

[0112] Compositions 1-4, 1-5, 2-4, and 2-5, which used the dispersants of Comparative Examples 2 and 5, exhibited poor viscosity stability after dispersion, particularly when containing a binder.

[0113] In addition, except that the compounds of Examples 1-5, Comparative Examples 1-4, and each of Comparative Examples 5 and 6 were used as dispersants, and 100.0 g of barium titanate powder (average particle size: 0.05 μm, determined by electron microscopy using SEM) was used as the powder, slurry compositions 3-1-11 and 4-1-11 were prepared by the same method as described above. The proportions of each raw material in the slurry are shown in Table 4.

[0114]

[0115]

[0116] As shown in Table 5, the slurry compositions 3-1 to 3-5 and 4-1 to 4-5 using the dispersants of Examples 1 to 5 of the present invention exhibit high viscosity stability after dispersion, regardless of whether a binder is present.

[0117] Compositions 3-6, 3-7, 4-6, and 4-7, which used the dispersants of Comparative Examples 1 and 2, exhibited poor viscosity stability after dispersion, particularly when containing a binder.

[0118] Compositions 3-8, 3-9, 4-8, and 4-9, which used the dispersants of Comparative Examples 3 and 4, did not produce slurries.

[0119] Compositions 3-10, 3-11, 4-10, and 4-11, which used the dispersants of Comparative Examples 5 and 6, exhibited poor viscosity stability after dispersion, particularly when containing a binder.

[0120] In addition, using the compounds of Example 1, Example 5, and Comparative Example 5 as dispersants and polyvinyl butyral resin (weight average molecular weight of 50,000) as a binder, slurry compositions 5-1 to 3 and 6-1 to 3 were prepared by the same method as described above, with the blending amounts of each raw material shown in Table 6.

[0121] Then, each composition was evaluated in the same manner as described above. The results are shown in Tables 6 and 7.

[0122]

[0123]

[0124] As shown in Table 7, the slurry compositions 5-1, 5-2, 6-1, and 6-2 using the dispersants of Examples 1 and 5 of the present invention exhibit high viscosity stability after dispersion, regardless of the presence or absence of a binder.

[0125] Compositions 5-3 and 6-3, which used the dispersant of Comparative Example 1, exhibited poor viscosity stability after dispersion, particularly when containing a binder.

Claims

1. A dispersant for particulate matter, characterized in that, It is a particulate dispersant compatible with one or more solvents selected from the group consisting of alcohol solvents, ether solvents, ketone solvents, and aromatic solvents. The particulate dispersant is formed from a polyether ester compound or its neutralized salt, wherein the polyether ester compound is an ester reaction product of the following components (a1) and (a2) and has an acid value of 85–220 mg KOH / g. Component (a1): The polyether compound represented by formula (1) below, HO-(AO) m -H····(1) In formula (1), AO is an oxidized alkenyl group with 2 to 3 carbon atoms, the oxyethylene group accounts for more than 20% by mass of the oxidized alkenyl AO, and m is the average number of moles of addition of the oxidized alkenyl AO, where m is 2 to 30. Component (a2): Succinic acid, trimellitic acid, succinic anhydride or trimellitic anhydride.

2. A slurry composition, characterized in that, The slurry composition contains 0.01 to 6% by mass of the following component (A), 1 to 10% by mass of the following component (B), 10 to 60% by mass of the following component (C), and the balance of the following component (D). Component (A): The particulate dispersant as described in claim 1, Ingredient (B): Polyvinyl butyral, Composition (C): Powder with an average particle size of less than 200 nm. Component (D): The solvent as described in claim 1.

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