Polyetherester Compounds

Abstract

To provide a powder amphiphatic dispersant that can dispersing particulates in a wide variety of solvents well.SOLUTION: A powder amphiphatic dispersant is composed of a polyether ester compound expressed by the following expression (1). (In the expression, EO is an oxyethylene group, and (a) is an average addition mol number of the oxyethylene group indicated by EO. AO is an oxyalkylene group of 3-4 of the carbon number, and (b) is an average addition mol number of the oxyalkylene group indicated by AO, an (a) is 1-40, and (b) is 0-10, where a and b satisfy the relationship of 0.5≤a / (a+b)≤1. A carbon atom in a heterocycle may be partially replaced by an oxygen atom. (m) is 1-2. RCOOM is a residue of a dibasic acid of the carbon number of 4-8. M is a hydrogen atom, alkaline metal, alkaline earth metal, ammonium or organic ammonium).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a dispersant capable of dispersing fine particles well in a wide variety of solvents. [Background technology]

[0002] The polarity, viscosity, and reactivity of polyalkylene glycol derivatives can be controlled by adjusting the type of constituent alkylene oxide and its degree of polymerization, thereby imparting properties such as flexibility and steric repulsion, and these derivatives are used in a variety of applications, such as cleaning agent compositions, water treatment agents, scale inhibitors, lubricants, plasticizers, and dispersants. As dispersants, copolymers of polyalkylene glycol monomers and carboxylic acid (salt) monomers have been proposed, and polyalkylene glycols are used to exhibit steric repulsion properties in a wide range of solvents, from water to hydrophobic solvents. Dispersants are used in various industrial fields to disperse organic or inorganic powders in various solvents. Examples of organic powders include organic pigments, and dispersion compositions containing organic pigments are used in paints, printing inks, inkjet inks, color filter resists, writing instrument inks, and the like. Examples of inorganic powders include ceramics and metal powders, and dispersion compositions containing ceramic powders are used in abrasives, fireproof materials, and the like, in addition to electronic components such as dielectric layers of laminated ceramic capacitors, semiconductor substrates, sensors, and liquid crystal display elements, and dispersion compositions containing metal powders are widely used as electronic materials for forming electrodes, such as paints, conductive pastes, and conductive inks. Patent Document 1 proposes an ester of polyoxypropylene monomethacrylic ether with enhanced lipophilicity and trimellitic anhydride in order to disperse zinc oxide in a non-aqueous solvent. On the other hand, when preparing an aqueous slurry using ceramic powder such as titanium oxide, polyacrylic acid or a neutral salt of polyacrylic acid is often used (see Patent Document 2). In this way, different dispersants are used depending on the solvent used. Since a variety of solvents are used in various industrial fields, many dispersants are required depending on the type of solvent. For this reason, dispersants are required to have the ability to disperse fine particles well in a wide variety of solvents. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-144402 A [Patent Document 2] JP 2011-105808 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dispersant capable of dispersing fine particles well in a wide variety of solvents. [Means for solving the problem]

[0005] Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems, and as a result have found that a polyether ester compound comprising a polyether having a specific structure and a dibasic acid can solve the above problems. That is, the present invention relates to the following [1] and [2]. [1] A polyether ester compound represented by the following formula (1):

[0006] [ka]

[0007] (In formula (1), EO is an oxyethylene group, and a is the average number of moles of the oxyethylene group represented by EO. AO is an oxyalkylene group having 3 to 4 carbon atoms; b is the average number of moles of the oxyalkylene group represented by AO added; a is 1 to 40; and b is 0 to 10. a and b satisfy the relationship 0.5≦a / (a+b)≦1. Some of the carbon atoms in the heterocycle may be replaced by oxygen atoms. m is 1 to 2. RCOOM is a residue of a dibasic acid having 4 to 8 carbon atoms. M is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium. [2] An amphiphilic dispersant for powders comprising the polyether ester compound according to [1]. Effect of the Invention

[0008] According to the present invention, fine particles such as organic or inorganic powders having a size of 1 μm or less can be dispersed satisfactorily in a wide variety of solvents. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the amphiphilic compound of the present invention will be described in order.

[0010] The compound of the present invention is a polyether ester compound consisting of a polyether represented by the following formula (1) and a dibasic acid. Hereinafter, the ester compound consisting of a polyether represented by the formula (1) and a dibasic acid will also be simply referred to as a "polyether ester compound."

[0011] [ka]

[0012] EO is an oxyethylene group, and a is the average number of moles of the oxyethylene group represented by EO. The b AOs are the same or different and are oxyalkylene groups having 3 to 4 carbon atoms, and the addition form may be random or block, and b is the average addition molar number of the oxyalkylene groups represented by AO. a is 1 to 40, and b is 0 to 10. Preferably, a is 1 to 25, and b is 0 to 10, and more preferably, a is 1 to 15, and b is 0 to 5. The order of addition of EO and AO is not particularly limited, and may be random or block-like.

[0013] The average number of moles a of oxyethylene groups added and the average number of moles b of oxyalkylene groups having 3 to 4 carbon atoms added satisfy the relationship 0.5≦a / (a+b)≦1. The polyoxyalkylene moiety (composed of an oxyalkylene group having 3 to 4 carbon atoms and an oxyethylene group) acts as a steric repulsion moiety in the dispersant structure when adsorbed to powder. a+b represents the sum of the average number of moles of oxyethylene groups added and the average number of moles of oxyalkylene groups having 3 to 4 carbon atoms added, and when a+b exceeds 50, the viscosity increases and the dispersant becomes difficult to handle. From this viewpoint, a+b is set to 50 or less, preferably 35 or less, and more preferably 20 or less. a / (a+b) means the balance between the highly hydrophilic polyoxyethylene group of the polyether chain in the polyether ester compound and the highly lipophilic poly(oxyalkylene) group (polyoxypropylene group, polyoxybutylene group, etc.) having 3 to 4 carbon atoms. If a / (a+b) is less than 0.6, the lipophilicity is too high, so that the solubility in polar solvents decreases, causing the polyether chain to shrink, and the steric repulsion effect decreases, which may result in a decrease in dispersibility. a / (a+b) is preferably 0.8 or more, and more preferably 0.9 or more. a+b means the polyether chain length per equivalent of active hydrogen bonded to a nitrogen atom, and satisfies 1≦a+b≦50. If a+b exceeds 50, the polyether chains are likely to be entangled, and the initial dispersibility may be reduced. In addition, the viscosity increases, making it difficult to handle. From the viewpoint of initial dispersibility and handling, a+b is preferably 1≦a+b≦35, and more preferably 1≦a+b≦25. From the viewpoint of solubility in highly polar solvents, it is most preferable that the polyether moiety consists of only oxyethylene groups. From the viewpoint of water solubility, it is preferred that some of the carbon atoms in the heterocycle are replaced with oxygen atoms, and it is more preferred that they are replaced with 1 to 2 oxygen atoms.

[0014] m is 1 to 2, and preferably m=2.

[0015] RCOOM is a reaction residue when a polyether and a dibasic acid having 4 to 8 carbon atoms are esterified, and is preferably succinic acid, maleic acid, or phthalic acid, and more preferably succinic acid or maleic acid.

[0016] M is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium. Examples of the alkali metal include lithium, sodium, and potassium. Examples of the alkaline earth metal include calcium, strontium, barium, magnesium, etc. Examples of the organic ammonium include alkanol ammonium derived from alkanol amines such as monoethanolamine, diethanolamine, and triethanolamine, and alkyl ammonium derived from alkyl amines such as diethylamine and triethylamine. M is preferably a hydrogen atom, ammonium or alkanolammonium, more preferably a hydrogen atom or alkanolammonium, and most preferably a hydrogen atom.

[0017] Next, a method for producing the polyether ester compound represented by formula (1) will be described.

[0018] The polyetherester compound represented by formula (1) can be produced by a first step of producing a polyether and a second step of reacting the polyether obtained in the first step with a dibasic acid or a dibasic acid anhydride.

[0019] The first step will be described. Polyethers can be produced by adding alkylene oxides appropriately to a nitrogen-containing heterocyclic compound having active hydrogen according to the desired structure. Examples of catalysts used in the addition reaction of alkylene oxide include alkali catalysts, such as oxides and hydroxides of alkali metals and alkaline earth metals, alcoholates, alkylamines such as triethylamine, and alkanolamines such as triethanolamine. In addition to the above alkali catalysts, Lewis acid catalysts such as boron trifluoride and tin tetrachloride can be used. The amount of catalyst used is generally 0.01 to 5.0% by mass based on the mass after the addition reaction is completed. The addition reaction of the alkylene oxide can be carried out, for example, in an atmosphere of an inert gas such as argon or nitrogen gas, at 50 to 200° C. and at 0.02 to 1.0 MPa, by continuously adding the alkylene oxide while applying pressure.

[0020] Next, the second step will be described. Regarding the dibasic acid or dibasic acid anhydride used in the second step, the dibasic acid includes succinic acid, maleic acid, and phthalic acid, and the dibasic acid anhydride includes succinic acid anhydride, maleic acid anhydride, and phthalic acid anhydride. Dibasic acid anhydride is preferable. The reaction ratio in the second step is preferably 0.7<(H) / (T)<1.2, more preferably (H) / (T)=1, where (H) is the mole number of hydroxyl groups of the heterocycle-derived polyether and (T) is the mole number of the dibasic acid or dibasic acid anhydride. In the second step, a catalyst may be used. Examples of the catalyst include tertiary amine compounds, such as triethylamine, triethylenediamine, N,N-dimethylbenzylamine, N-methylmorpholine, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene.

[0021] Both the first and second steps may be carried out without a solvent, or a suitable dehydrated organic solvent may be used. After the reaction is completed, the solvent used in the reaction may be removed by an operation such as distillation, or may be used as it is as part of the product. The reaction temperature is 60 to 150°C, preferably 70 to 120°C, and more preferably 80 to 100°C.

[0022] The polyether ester compound of the present invention may be neutralized with an amine, such as ammonia, alkylamines such as methylamine, dimethylamine, and ethylamine, and alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, and one or more selected from these may be used.

[0023] The polyether ester compound of the present invention can be used as a dispersant for powders either as a single compound or mixed with other additives commonly used in the art (thickeners, plasticizers, antistatic agents, etc.) (hereinafter, these may be collectively referred to as "amphiphilic dispersants for powders made of polyether ester compounds").

[0024] The "amphiphilic dispersant for powder consisting of a polyether ester compound" of the present invention can be used as a dispersant to disperse the object to be dispersed (powder) in a solvent by a method commonly used in the art.

[0025] The dispersant of the present invention can disperse organic or inorganic powders. Examples of the organic powder include organic pigments such as azo, diazo, condensed azo, thioindigo, indanthrone, quinacridone, anthraquinone, benzimidazolone, phenylene, phthalocyanine, anthrapyridine, and dioxazine. Examples of inorganic powders include metal powders, alloy powders consisting of two or more types of metals or metals and nonmetals, composite powders consisting of metal powders or alloy powders, and mixed powders consisting of two or more types of inorganic powders or inorganic powders mixed with other powders. Other examples of inorganic powders include powders of silicate compounds, carbonate compounds, sulfate compounds, hydroxide compounds, oxide compounds, carbide compounds, nitride compounds, titanate compounds, and the like.

[0026] Preferred examples of the dispersion include metal powders such as nickel, cobalt, palladium, copper, silver, gold, and platinum; powders of oxide compounds such as zirconium oxide, magnesium oxide, aluminum oxide, iron oxide, zinc oxide, indium tin oxide, and titanium oxide; and powders of titanate compounds such as barium titanate, calcium titanate, and strontium titanate.

[0027] From the viewpoint of usefulness, the average particle size of the dispersion is preferably 0.01 to 10 μm, more preferably 0.01 to 5 μm, and even more preferably 0.01 to 1 μm. The average particle size of the dispersion can be measured by a microtrack method.

[0028] Examples of solvents for dispersing the dispersion using the dispersant of the present invention include aromatic hydrocarbon solvents such as toluene and xylene, hydrocarbon solvents such as cyclohexane, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and n-propyl acetate, glycol ether solvents such as ethylene glycol monoethyl ether and ethylene glycol monoisopropyl ether, glycol ether ester solvents such as ethylene glycol monoethyl ether acetate and ethylene glycol monoisopropyl ether acetate, terpene solvents such as terpineol and dihydroterpineol, alcohol solvents such as methanol, ethanol, and n-propanol, and water. One or more solvents selected from these can be used.

[0029] As a solvent for dispersing the dispersion with the dispersant of the present invention, a high polarity solvent having a solubility parameter (SP value) of 10 or more, a low polarity solvent having a solubility parameter (SP value) of less than 10, or a mixed solvent of two or more of them can be used. For example, the SP values ​​of water, ethanol, and toluene are 23.4, 12.7, and 8.8, respectively, and the SP values ​​of a water:ethanol=1:1 (wt%) mixed solvent and a toluene:ethanol=1:1 (wt%) mixed solvent are 20.2 and 11.1, respectively.

[0030] The polyether ester compound of the present invention is an "amphiphilic" dispersant, where amphiphilic means that it is soluble in both highly polar solvents having an SP value of 10 or more and low polarity solvents having an SP value of less than 10, and is particularly soluble in solvents (or mixed solvents) having an SP value of 5 to 25. EXAMPLES

[0031] Next, the present invention will be described in more detail with reference to examples and comparative examples.

[0032] (Synthesis Example 1: Synthesis of polyether ester compound 1) A 5-liter stainless steel pressure vessel equipped with an agitator, pressure gauge, thermometer, safety valve, gas inlet tube, exhaust pipe, cooling coil, and steam jacket was charged with 261 g (3 mol) of tetrahydro-1,4-oxazine (trade name: Morpholine, manufactured by Tokyo Chemical Industry Co., Ltd.), and the system was replaced with nitrogen gas. Under stirring at 140°C and 0.05 to 0.5 MPa (gauge pressure), 132 g (3 mol) of ethylene oxide was added from a separately prepared pressure vessel through the gas inlet tube while pressurizing with nitrogen gas. After the addition was completed, the reaction was continued under the same conditions until the internal pressure became constant. After cooling to 40°C, 1.2g of sodium methoxide was added, and the system was replaced with nitrogen gas. After heating to 140°C under stirring, 1850g (42mol) of ethylene oxide was added under 0.05-0.5MPa conditions while pressurizing with nitrogen gas through a gas inlet tube. After the addition was completed, the reaction was continued under the same conditions until the internal pressure became constant. Thereafter, the reaction product was taken out of the pressure vessel, neutralized with hydrochloric acid to pH 9-11, and reduced pressure treatment was performed at 100°C for 1 hour to remove the contained moisture, and finally, the salt was removed by filtration to obtain 2100g of polyether. The hydroxyl value of the obtained polyether was 75, and the molecular weight calculated from the hydroxyl value was 748.

[0033] Next, 224g (0.3mol) of the polyether obtained above and 45g (0.3mol) of phthalic anhydride (Kanto Chemical Co., Ltd.) were charged into a 0.5L glass reaction vessel equipped with a stirrer, a thermometer, and a gas inlet tube, and reacted at 90°C for 2 hours. The reaction was terminated when it was confirmed by measuring the acid value that 95% or more of the acid anhydride had been half-esterified. This resulted in the production of polyether ester compound 1 (compound 1 in Table 1 below).

[0034] Polyether ester compounds 2 to 6 and compound 9 in Table 1 were synthesized by carrying out the operations similar to those in Synthesis Example 1, except that the morpholine and ethylene oxide in Synthesis Example 1 were appropriately replaced with other compounds.

[0035] [Table 1]

[0036] (Examples 1 to 6 and 13) Using the polyether ester compounds 1 to 6 and 9 as dispersants, dispersion compositions were prepared as follows. 2.0 g of titanium oxide (product name: Super Titania F-2, manufactured by Showa Denko Ceramics, average particle size: 60 nm), 1.3 g of the following solvent, and 0.2 g of dispersant were weighed into a 50 mL screw tube, and a dispersion treatment was carried out for 2 minutes using a planetary centrifugal mixer to obtain a slurry-like dispersion composition. In industry, titanium oxide is often processed in an aqueous system, so the solvents used were ion-exchanged water, a mixed solution of ion-exchanged water:ethanol = 1:1 (wt%), ethanol, and a mixed solution of toluene:ethanol = 1:1 (wt%). The dispersion compositions obtained using polyether ester compounds 1 to 6 and 9 in Table 1 were designated as Examples 1 to 6 and 13, respectively.

[0037] Comparative Example 1 In Comparative Example 1, a dispersion composition was prepared in the same manner as in Examples 1 to 6 and 13, except that a polycarboxylic acid-based polymer dispersant (Compound 7) was used as the aqueous dispersant instead of the polyether ester-based compound. Compound 7 is a copolymer of water-soluble allyl polyether and maleic anhydride, and was prepared with reference to Example 1 of JP-A-1-109.

[0038] (Distributed Test) Dispersion tests were carried out using the dispersion compositions of Examples 1 to 6 and 13 and Comparative Example 1. For each dispersion composition, the shear viscosity was measured at a temperature of 20° C. and at shear rates of 0.1 to 100 (1 / s) using a dynamic viscoelasticity device. The shear viscosity at a shear rate of 1 (1 / s) is shown in Table 2. The evaluation criteria for dispersibility were based on the shear viscosity at a shear rate of 1 (1 / s) and were evaluated as follows. <Evaluation criteria> ◎: Shear viscosity is 100 Pa s or less, and dispersibility is very good. ○: Shear viscosity is 200 Pa s or less, and dispersibility is good. △: Shear viscosity exceeds 200 Pa s, and dispersibility is low. ×: No slurry was obtained.

[0039] [Table 2]

[0040] The dispersion compositions of Examples 1 to 6 and 13, to which the polyether ester compounds 1 to 6 and 9 according to the present invention were added, all exhibited good dispersibility, and it was found that the effect on dispersibility was small even when the type of solvent was changed. On the other hand, the dispersion composition of Comparative Example 1 to which compound 7 was added did not give a slurry when the polarity of the solvent was reduced, and even when a slurry was obtained using ion-exchanged water, the dispersibility was significantly inferior.

[0041] (Examples 7 to 12 and 14) Using the polyether ester compounds 1 to 6 and 9 as dispersants, dispersion compositions were prepared as follows. 2.0 g of barium titanate (product name: KZM-50, manufactured by Sakai Chemical Industry Co., Ltd., average particle size: 50 nm), 0.5 g of the following solvent, and 0.1 g of dispersant were weighed into a 50 mL screw tube, and a dispersion treatment was carried out for 2 minutes using a planetary centrifugal mixer to obtain a slurry-like dispersion composition. In industry, barium titanate is often processed in non-aqueous systems, so the solvents used were a mixed solution of ion-exchanged water:ethanol = 1:1 (wt%), ethanol, a mixed solution of toluene:ethanol = 1:1 (wt%), and toluene, respectively. The dispersion compositions obtained using the polyether ester compounds 1 to 6 and 9 were designated as Examples 7 to 12 and 14, respectively.

[0042] Comparative Example 2 In Comparative Example 2, a dispersion composition was prepared in the same manner as in Examples 7 to 12 and 14, except that a polyetherester-based compound (Compound 8) was used as the non-aqueous dispersant instead of the polyetherester-based compound. Compound 8 is an ester of polyether capped at one end with a long-chain alkyl group and trimellitic anhydride, and was prepared with reference to compound 3 in JP 2016-147261 A.

[0043] (Distributed Test) Dispersion tests were carried out using the dispersion compositions of Examples 7 to 12 and 14 and Comparative Example 2. For each dispersion composition, the shear viscosity was measured at a temperature of 20°C and at shear rates of 0.1 to 100 (1 / s) using a dynamic viscoelasticity device. The shear viscosity at a shear rate of 1 (1 / s) is shown in Table 3. The evaluation standard for dispersibility is the shear viscosity at a shear rate of 1 (1 / s) and is evaluated as follows. <Evaluation criteria> ◎: Shear viscosity is 50 Pa s or less, and dispersibility is very good. ○: Shear viscosity is 100 Pa s or less, and dispersibility is good. △: Shear viscosity exceeds 100 Pa s, and dispersibility is low. ×: No slurry was obtained.

[0044] [Table 3]

[0045] The dispersion compositions of Examples 7 to 12 and 14, in which the polyether ester compounds 1 to 6 and 9 according to the present invention were added, all exhibited good dispersibility, and it was found that the effect on dispersibility was small even when the type of solvent was changed. On the other hand, the dispersion composition of Comparative Example 2, in which Compound 8 was added, exhibited significantly poorer dispersibility when the polarity of the solvent was increased, demonstrating the large effect of changing the type of solvent. [Industrial Applicability]

[0046] The present invention provides a dispersant that can disperse fine particles well in a wide variety of solvents.

Claims

[Claim 1] An amphiphilic dispersant for powders comprising a polyether ester compound represented by the following formula (1): 【Chemistry 1】 (In formula (1), EO is an oxyethylene group, and a is the average number of moles of the oxyethylene group represented by EO. AO is an oxyalkylene group having 3 to 4 carbon atoms; b is the average number of moles of the oxyalkylene group represented by AO added; a is 1 to 40; and b is 0 to 10. a and b satisfy the relationship 0.5≦a / (a+b)≦1. Some of the carbon atoms in the heterocycle may be replaced by oxygen atoms. m is 1 to 2. RCOOM is a residue of a dibasic acid having 4 to 8 carbon atoms. M is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.

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