Dispersant for metal oxide particles, and dispersion

Abstract

To provide: a dispersant for metal oxide particles with which it is possible to satisfactorily disperse metal oxide particles; and a dispersion that has excellent metal oxide particle dispersibility and with which it is possible to form a cured product having both good transparency and good refractive index.SOLUTION: Tes dispersant for metal oxide particles is used for dispersing metal oxide particles, and contains a compound represented by the general formula (1) in the figure (where R1 represents an alkyl group, m represents an integer of 2-7, and n represents an integer of 5-15). The dispersion contains the dispersant for metal oxide particles, metal oxide particles, and an acrylic compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dispersant used to disperse metal oxide particles and a dispersion containing the dispersant. [Background technology]

[0002] Metal oxide particles have unique properties not found in organic polymer particles, making them extremely useful materials, for example, as various additives and fillers. Typical properties of metal oxide particles include a high refractive index, photocatalytic function, toughness, and transparency. By incorporating metal oxide particles with these properties into a target material, such as a resin, new properties can be imparted to the target material. Therefore, metal oxide particles are extremely valuable in creating new functional materials.

[0003] It is known that the various properties of metal oxide particles as described above depend strongly on their particle size, and in particular, when particle sizes reach the nanometer range, i.e., the so-called metal oxide nanoparticles range, new functions that are not possible with particles on the micrometer order can be realized. For this reason, the development of functional materials using nano-sized metal oxide particles has been actively pursued in recent years.

[0004] On the other hand, when the particle size of metal oxide particles reaches the nanoparticle size range, aggregation of particles due to an increase in specific surface area and other factors is likely to occur, and this aggregation becomes particularly pronounced in liquids such as solvents. From this perspective, it is also important to develop a technology that can more highly disperse metal oxide particles in solvents. For example, Patent Document 1 discloses a technology for dispersing zirconium oxide particles in a dispersion medium using a dispersant made of a compound having a specific structure. This technology is said to make it possible to disperse zirconium oxide particles even in nanometer sizes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-007144 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been a demand for even higher dispersibility than before in order to more effectively utilize the excellent properties of metal oxide particles. By suppressing aggregation of metal oxide particles and further improving dispersibility, the inherent properties of metal oxide particles can be significantly exhibited. For example, materials incorporating highly dispersible metal oxide particles are expected to exhibit significantly improved functions such as a higher refractive index and transparency. From this perspective, there has been a strong demand for the development of dispersants that can highly disperse metal oxide particles.

[0007] The present invention has been made in view of the above, and aims to provide a dispersant for metal oxide particles that can disperse metal oxide particles well. Another aim of the present invention is to provide a dispersion that has excellent dispersibility of metal oxide particles and is suitable for forming a cured product that has both good transparency and a good refractive index. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above object, the present inventors have discovered that the above object can be achieved by applying a compound having a specific structure, and have thus completed the present invention.

[0009] That is, the present invention includes, for example, the subject matter described in the following sections. Item 1 A dispersant used to disperse metal oxide particles, The following general formula (1)

[0010] [ka]

[0011] (In formula (1), R 1 represents an alkyl group, m is a number from 2 to 7, and n is a number from 5 to 15. A dispersant for metal oxide particles, comprising a compound represented by the formula: Section 2 In the formula (1), R 1 Item 2. The dispersant for metal oxide particles according to Item 1, wherein is an alkyl group having 1 to 4 carbon atoms. Section 3 Item 3. A dispersion comprising the dispersant for metal oxide particles according to Item 1 or 2, metal oxide particles, and an acrylic compound. [Effects of the Invention]

[0012] The dispersant for metal oxide particles of the present invention can disperse metal oxide particles well.

[0013] The dispersion of the present invention has excellent dispersibility of metal oxide particles and can form a cured product that has both good transparency and a good refractive index. DETAILED DESCRIPTION OF THE INVENTION

[0014]

[0023] In the present specification, the terms "contain" and "comprise" include the concepts of "contain," "comprise," "consist essentially of," and "consist only of."

[0015] 1. Dispersants for metal oxide particles The dispersant for metal oxide particles of the present invention contains a compound represented by the following general formula (1).

[0016] [ka]

[0017] Here, in formula (1), R 1 represents an alkyl group, m is an integer of 2 to 7, and n is an integer of 5 to 15.

[0018] The dispersant for metal oxide particles of the present invention (hereinafter sometimes simply referred to as "the dispersant of the present invention") contains the above-mentioned compound, and thus has the property of being able to disperse metal oxide particles well. Therefore, the dispersant of the present invention can be suitably used as a raw material for forming a dispersion described below, and is particularly optimal as a dispersant used to disperse metal oxide particles.

[0019] The dispersion contains the dispersant for metal oxide particles of the present invention and metal oxide particles, and therefore has excellent dispersibility of the metal oxide particles, and can maintain a good dispersion state even in a cured product formed by curing the dispersion. Furthermore, the cured product obtained from the dispersion has good transparency and a good refractive index, and can be suitably used in various applications where these properties are required.

[0020] In the formula (1), R 1 may be a linear alkyl group or a branched alkyl group, and is preferably a linear alkyl group.

[0021] In the formula (1), R 1 The number of carbon atoms in the alkyl group R is not particularly limited, and can be, for example, about 1 to 10, preferably 1 to 4, from the viewpoint of easily increasing the dispersibility of the metal oxide particles. 1 is preferably an alkyl group having 1 to 4 carbon atoms (1 or more and 4 or less). In this case, it is possible to further improve the dispersibility of the metal oxide particles. The alkyl group having 1 to 4 carbon atoms is preferably linear.

[0022] R 1 Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0023] In the formula (1), m is a number from 2 to 7, i.e., a number from 2 to 7. If m is less than 2, the dispersibility of the metal oxide particles may decrease, and if m exceeds 7, the dispersibility of the metal oxide particles may decrease. m is preferably 3 or more and 6 or less. m may be an integer or a decimal point.

[0024] In the formula (1), the method for adjusting the value of m is not particularly limited, and for example, the value can be adjusted by appropriately selecting the type of raw material (cyclic ester compound, etc.) used when producing the compound represented by formula (1).

[0025] In the formula (1), n ​​is "-(CH2) m "n" means the repeating unit of the "-COO-" moiety, more specifically the number average repeating unit, in other words, n means the number average degree of polymerization of the compound represented by formula (1).

[0026] n is a number from 5 to 15, i.e., a number between 5 and 15. If n is less than 5, the dispersibility of the metal oxide particles may decrease, and if n exceeds 15, the dispersibility of the metal oxide particles may decrease. n is preferably 6 or more, more preferably 7 or more, and even more preferably 8 or more, and is preferably 14 or less, more preferably 13 or less, even more preferably 12 or less, and particularly preferably 11 or less. The value of n can be estimated from the 1H-NMR spectrum of the compound represented by formula (1). n may be an integer or a decimal point.

[0027] In the formula (1), the method for adjusting the value of n is not particularly limited, and for example, it can be adjusted by appropriately selecting the proportions of the raw materials (cyclic ester compound and fatty acid) used when producing the compound represented by formula (1).

[0028] The method for producing the compound represented by formula (1) is not particularly limited. For example, the compound represented by formula (1) can be produced by reacting a cyclic ester compound with a fatty acid.

[0029] The cyclic ester compound can be exemplified by a compound represented by the following general formula (2).

[0030] [ka]

[0031] In formula (2), m has the same meaning as in formula (1). The compound represented by formula (2) is -(CH2) m - is a cyclic compound in which the ester bonded to the ring.

[0032] Examples of the compound represented by the formula (2) include ε-caprolactone and γ-butyrolactone.

[0033] The fatty acid may be, for example, a saturated fatty acid. Specifically, the fatty acid may have a linear alkyl group. The alkyl group may be a group represented by R 1 Examples of the alkyl group include the same alkyl groups as those shown in the above.

[0034] When the compound represented by formula (1) is produced by reacting the cyclic ester compound with the fatty acid, the reaction conditions are not particularly limited, and a wide variety of reaction conditions, such as those for known ring-opening polymerization and known dehydration reactions, can be used. In the reaction, a catalyst, water, etc. can be used as needed, and p-toluenesulfonic acid can be used as the catalyst. The amounts of catalyst and water used are not particularly limited, and can be, for example, catalytic amounts. For purification after the reaction, an alkali such as sodium hydroxide can be used. The reaction temperature and reaction time for the ring-opening polymerization and dehydration reaction are also not particularly limited, and can be the same as those for known reactions.

[0035] The dispersant of the present invention may contain other components in addition to the compound represented by formula (1), or may consist solely of the compound represented by formula (1). The dispersant of the present invention preferably contains 90% by mass or more of the compound represented by formula (1), more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0036] The dispersant of the present invention can disperse metal oxide particles well. Examples of the types of metal oxide particles include a wide range of metal oxide particles contained in the dispersion described below, and is particularly suitable for dispersing zirconium oxide (zirconia), titanium oxide (titania), etc.

[0037] The dispersant of the present invention can disperse metal oxide particles well in various solvents, among which the acrylic compounds described below can be preferably used as the solvent.

[0038] When dispersing metal oxide particles using the dispersant of the present invention, for example, the amount of dispersant used per 100 parts by mass of metal oxide particles can be 0.5 to 30 parts by mass, preferably 1 to 20 parts by mass, more preferably 3 to 18 parts by mass, and even more preferably 4 to 16 parts by mass.

[0039] 2. Dispersion and cured product of the dispersion The dispersion of the present invention contains the above-mentioned dispersant for metal oxide particles, metal oxide particles, and an acrylic compound. Because the dispersion contains the dispersant of the present invention, it has excellent dispersibility of the metal oxide particles.

[0040] (metal oxide particles) In the metal oxide particles, the type of metal can be, for example, one metal selected from the group consisting of metal elements belonging to Periods 4, 5, and 6 of the Periodic Table (IUPAC 1991), and among these, metal elements of Groups 2 to 14 are preferred.

[0041] More specifically, the metal element constituting the metal oxide particles is preferably a metal that can impart a high refractive index when a metal oxide is formed, such as zirconium, titanium, tin, antimony, zinc, cerium, indium, or yttrium.

[0042] Specific examples of metal oxide particles include zirconium oxide, titanium oxide, tin oxide, antimony pentoxide, zinc oxide, cerium oxide, tin-doped indium oxide, antimony-doped tin oxide, and yttrium oxide. Of these, zirconium oxide, titanium oxide, and tin oxide are preferred, zirconium oxide and titanium oxide are more preferred, and zirconium oxide is particularly preferred.

[0043] In the dispersion of the present invention, the size of the metal oxide particles is not particularly limited as long as it does not reduce dispersibility. For example, the D50 volume average particle diameter of the metal oxide particles is preferably 1 nm or more, more preferably 2 nm or more, even more preferably 3 nm or more, and particularly preferably 5 nm or more, and is preferably 1000 nm or less, more preferably 100 nm or less, even more preferably 50 nm or less, and particularly preferably 30 nm or less. The D50 volume average particle diameter of the metal oxide particles refers to the particle diameter at the point where the volume cumulative distribution is 50% on the particle size distribution curve. The D50 volume average particle diameter of the metal oxide particles refers to a value measured using a dynamic light scattering (DLS) particle size distribution analyzer (Nanotrac Wave II (manufactured by Microtrack Bell)).

[0044] The shape of the metal oxide particles is not particularly limited, and may be, for example, the same as that of known metal oxide particles.

[0045] The metal oxide particles can be obtained, for example, in the form of a powder or a dispersion liquid from a commercial product, etc. Alternatively, the metal oxide particles can be produced, for example, by a known production method.

[0046] (acrylic compounds) The acrylic compound contained in the dispersion of the present invention serves as a dispersion medium for the metal oxide particles in the dispersion, and since the acrylic compound is polymerizable, it is also a component that can become a polymer by curing the dispersion.

[0047] Examples of acrylic compounds include (meth)acrylate compounds. In this specification, "(meth)acrylic" means "acrylic" or "methacrylic", and "(meth)acrylate" means "acrylate" or "methacrylate". The (meth)acrylate compound is preferably one or more compounds selected from the group consisting of monofunctional (meth)acrylate compounds and polyfunctional (meth)acrylate compounds.

[0048] Specific examples of the monofunctional (meth)acrylate compound include alkyl (meth)acrylates in which the alkyl group has 1 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. Acrylates; (meth)acrylate compounds having an aromatic ring such as benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 3-phenoxybenzyl acrylate, and EO-modified orthophenylphenol acrylate; alkoxyalkyl (meth)acrylates such as butoxyethyl (meth)acrylate; aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate, triethylene glycol monobutyl ether (meth)acrylate Polyalkylene glycol monoalkyl ether (meth)acrylates such as tetraethylene glycol monomethyl ether (meth)acrylate, hexaethylene glycol monomethyl ether (meth)acrylate, octaethylene glycol monomethyl ether (meth)acrylate, nonaethylene glycol monomethyl ether (meth)acrylate, dipropylene glycol monomethyl ether (meth)acrylate, heptapropylene glycol monomethyl ether (meth)acrylate, and tetraethylene glycol monoethyl ether (meth)acrylate; polyalkylene glycol monoaryl ether (meth)acrylates such as hexaethylene glycol monophenyl ether (meth)acrylate; (meth)acrylate compounds having an alicyclic structure such as cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, and methylene oxide-added cyclodecatriene (meth)acrylate; (meth)acrylate compounds having a heterocyclic ring such as (meth)acryloylmorpholine and tetrahydrofurfuryl (meth)acrylate;Fluorinated alkyl (meth)acrylates such as heptadecafluorodecyl (meth)acrylate; (meth)acrylate compounds having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate, and octapropylene glycol mono(meth)acrylate; glycidyl ( (Meth)acrylate compounds having a glycidyl group such as 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate, 2-(meth)acryloyloxyethyl isocyanate, and other (meth)acrylate compounds having an isocyanate group; polyalkylene glycol mono(meth)acrylates such as tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate, and octapropylene glycol mono(meth)acrylate; and the like.

[0049] Specific examples of polyfunctional (meth)acrylate compounds include alkylene glycol di(meth)acrylates such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate; polyalkylene glycol di(meth)acrylates such as polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate; tri(meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, and tris(2-acryloyloxyethyl)isocyanurate; ethylene oxide-added pentaerythritol tetra(meth)acrylate, and trimethylolpropane tetra(meth)acrylate; tetra(meth)acrylate compounds such as tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; (meth)acrylate compounds having an alicyclic structure such as tricyclodecane dimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, 1,3-adamantane dimethanol di(meth)acrylate, hydrogenated bisphenol A (poly)ethoxy di(meth)acrylate, hydrogenated bisphenol A (poly)propoxy di(meth)acrylate, hydrogenated bisphenol F (poly)ethoxy di(meth)acrylate, hydrogenated bisphenol F (poly)propoxy di(meth)acrylate, hydrogenated bisphenol S (poly)ethoxy di(meth)acrylate, and hydrogenated bisphenol S (poly)propoxy di(meth)acrylate.

[0050] The acrylic compound is preferably a monofunctional (meth)acrylate compound, and more preferably a (meth)acrylate compound having an aromatic ring as described above. In this case, not only is the dispersibility of the metal oxide particles likely to be improved, but the refractive index of the cured product is also likely to be increased.

[0051] (Dispersion and cured product of dispersion) In the dispersion of the present invention, the content ratios of the dispersant, metal oxide particles, and acrylic compound can be various as long as the effects of the present invention are not impaired.

[0052] In the dispersion of the present invention, the content of the metal oxide particles can be 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more, based on the total mass of the dispersant, metal oxide particles, and acrylic compound. The content of the metal oxide particles can be 80% by mass or less, preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, based on the total mass of the dispersant, metal oxide particles, and acrylic compound.

[0053] In the dispersion of the present invention, the content of the dispersant can be 0.5 parts by mass or more, preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 4 parts by mass or more, and particularly preferably 5 parts by mass or more, per 100 parts by mass of the metal oxide particles. The content of the dispersant can be 30 parts by mass or less, preferably 25 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 13 parts by mass or less, per 100 parts by mass of the metal oxide particles.

[0054] In the dispersion of the present invention, the content of the acrylic compound can be 50 parts by mass or more, preferably 60 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, and particularly preferably 90 parts by mass or more, per 100 parts by mass of the metal oxide particles. The content of the acrylic compound can be 300 parts by mass or less, preferably 250 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 150 parts by mass or less, and particularly preferably 130 parts by mass or less, per 100 parts by mass of the metal oxide particles.

[0055] The dispersion of the present invention may contain other components in addition to the dispersant, metal oxide particles, and acrylic compound, as long as the effects of the present invention are not impaired. Examples of other components include the photopolymerization initiator described below, as well as additives such as light stabilizers, antioxidants, preservatives, flame retardants, pigments, colorants, mildew inhibitors, and lubricants. When the photopolymerization initiator is contained in the coating agent described below, it does not need to be contained in the dispersion. The additives contained in the dispersion may be one or more types.

[0056] The method for preparing the dispersion of the present invention is not particularly limited, and for example, the dispersion can be prepared by blending a dispersant, metal oxide particles, an acrylic compound, and other components added as needed in a predetermined ratio. The metal oxide particles used to prepare the dispersion may be in a powder state, may be dispersed in a solvent, or may be in other forms. For example, a commercially available mixer or the like can be used to prepare the dispersion, and a disperser or the like can also be used as needed to disperse the metal oxide particles.

[0057] The dispersion of the present invention is a dispersion of metal oxide particles in an acrylic compound. Since the dispersion of the present invention contains a dispersant for metal oxide particles, the dispersion has excellent dispersibility of the metal oxide particles and also has high transparency.

[0058] The dispersion of the present invention contains a polymerizable (curable) acrylic compound, and therefore can be cured to form a cured product. For example, the dispersion of the present invention is applied to a substrate to form a coating film, and the coating film is cured to form a cured product (which can also be called a cured film) of the dispersion.

[0059] To promote curing of the dispersion, the dispersion may contain a photopolymerization initiator. The type of photopolymerization initiator is not particularly limited, and for example, a wide range of known photopolymerization initiators can be used. Examples of photopolymerization initiators include polymerization initiators that are activated by active energy rays such as ultraviolet rays.

[0060] Examples of the photopolymerization initiator include aromatic ketones such as benzophenone, aromatic compounds such as anthracene and α-chloromethylnaphthalene, and sulfur compounds such as diphenyl sulfide and thiocarbamate.

[0061] Examples of polymerization initiators using active energy rays other than visible light, such as ultraviolet rays, include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzil dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl- Examples of such an alkyl ester include 1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone).

[0062] Commercially available active energy ray polymerization initiators include, for example, Omnirad 184, 369, 651, 500, 819, 907, 784, 2959, 1000, 1300, 1700, 1800, and 1850 manufactured by IGM Resins BV, Lucirin TPO manufactured by BASF, Ubecryl P36 manufactured by UCB, Esacure KIP150, KIP100F, KT37, KT55, KTO46, TZT, and KIP75LT manufactured by Fratelli Lamberti, and Kayacure DETX manufactured by Nippon Kayaku Co., Ltd.

[0063] When the dispersion contains a photopolymerization initiator, the content of the photopolymerization initiator is not particularly limited and is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass per 100 parts by mass of the acrylic compound.

[0064] Examples of the substrate for forming a cured product of the dispersion of the present invention include a resin film, a resin sheet, and a resin plate, and may also be a substrate formed of glass, metal, inorganic material, etc.

[0065] The method for applying the dispersion to the substrate is not particularly limited, and for example, the dispersion can be applied to the substrate using a known coating machine such as a bar coater, thereby forming a coating film of the dispersion on the substrate. The method for curing the coating is also not particularly limited, and examples thereof include a method of irradiating the coating film with active energy rays and a method of heating the coating film. Examples of active energy rays include high-pressure mercury lamps, electron beams, gamma rays, carbon arc lamps, xenon lamps, and metal halide lamps. When curing by heating, the composition can be cured by heating to a temperature range of 60 to 250°C.

[0066] Since the cured product is formed from the dispersion of the present invention, the metal oxide particles can maintain a good dispersion state even in the cured product, and therefore the metal oxide particles are less likely to aggregate in the cured product, which can result in the cured product having excellent transparency.

[0067] Furthermore, since the dispersibility of the metal oxide particles in the cured product is excellent, the properties of the metal oxide particles themselves are likely to be effectively exhibited. For example, if the metal oxide particles are capable of imparting a high refractive index, the high refractive index of the metal oxide particles is likely to be reflected in the cured product (film), resulting in a cured product with a high refractive index.

[0068] Furthermore, the cured product formed from the dispersion of the present invention has excellent transparency because it contains a specific dispersant, metal oxide particles, and a polymer of an acrylic compound.

[0069] The shape of the cured product formed from the dispersion of the present invention is not particularly limited, and examples thereof include various shapes such as a film, a plate, a lump (block), and a particle.

[0070] As described above, the dispersion of the present invention can form a cured product having the above-mentioned various properties, and therefore can be applied to various applications, and is suitable for use as, for example, a coating agent for forming a cured product. Such a coating agent contains the dispersion of the present invention and can contain other components as necessary. For example, when the dispersion does not contain the above-mentioned photopolymerization initiator, the coating agent can contain the same photopolymerization initiator as above, and the content thereof is as described above.

[0071] By using the coating agent, a cured product of the dispersion can be formed, and therefore it can be used for coating a substrate, etc., and can impart, for example, high transparency and refractive index.

[0072] In specifying the inventions included in the present disclosure, the components (properties, structures, functions, etc.) described in the embodiments of the present disclosure may be combined in any manner. In other words, the present disclosure includes all subject matter consisting of all combinations of the components that can be combined as described in this specification. [Example]

[0073] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] Example 1 To 1.0 mol of propionic acid, 8.0 mol of ε-caprolactone, 0.2 mol of p-toluenesulfonic acid monohydrate, and 2.2 mol of pure water were added, and the mixture was stirred at 80°C for approximately 8 hours. After that, the mixture was further stirred for another 2 hours while dehydrating under reduced pressure (30 kPa). Finally, the propionic acid remaining in the reaction system was distilled off, and after a purification step (washed with water three times) and a drying step, the mixture was purified to obtain Dispersant 1 (R of Formula (1)). 1 is ethyl, m is 5, and n is 10).

[0075] (Comparative Example 1a) To 1.0 mol of propionic acid, 18.0 mol of ε-caprolactone, 0.5 mol of p-toluenesulfonic acid monohydrate, and 5.1 mol of pure water were added, and the mixture was stirred at 80°C for approximately 8 hours. After that, the mixture was dehydrated under reduced pressure (30 kPa) and stirred for another 2 hours. Finally, the propionic acid remaining in the reaction system was distilled off, and the mixture was purified (washed with water three times) and dried to give Dispersant 1 (R of Formula (1)). 1 The compound (wherein m is ethyl, m is 5, and n is 20) was obtained.

[0076] (Comparative example 1b) To 1.0 mol of propionic acid, 2.0 mol of ε-caprolactone, 0.02 mol of p-toluenesulfonic acid monohydrate, and 0.2 mol of pure water were added, and the mixture was stirred at 80°C for approximately 8 hours. After that, the mixture was further stirred for another 2 hours while dehydrating under reduced pressure (30 kPa). Finally, the propionic acid remaining in the reaction system was distilled off, and the mixture was purified (washed with water three times) and dried to give Dispersant 1 (R in Formula (1)). 1 The compound (wherein m is ethyl, m is 5, and n is 3) was obtained.

[0077] (raw materials) Predetermined raw materials were selected from the raw materials shown below (metal oxide particles, dispersant for metal oxide particles, acrylic compound) to prepare dispersions of Examples 2-1 to 2-9 and Comparative Examples 2 to 5 described below.

[0078] <Metal oxide particles> Metal oxide particles 1: Zirconium oxide methanol dispersion (D50 = approx. 10 nm) manufactured by Sakai Chemical Industry Co., Ltd. Metal oxide particles 2: Zirconium oxide methanol dispersion (D50 = approx. 3 nm) manufactured by Sakai Chemical Industry Co., Ltd. Metal oxide particles 3: Zirconium oxide methanol dispersion (D50 = approx. 50 nm) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.

[0079] <Dispersant for metal oxide particles> Dispersant 1: the compound obtained in Example 1 Dispersant C1 (for comparison): the compound obtained in Comparative Example 1a Dispersant C2 (for comparison): the compound obtained in Comparative Example 1b Dispersant C3 (for comparison): ω-carboxy-polycaprolactone (n≒2) monoacrylate (Toagosei Co., Ltd. "Aronix M-5300 (registered trademark)") Dispersant C4 (for comparison): Polyoxyethylene alkyl (C8) ether phosphate ester (Dai-ichi Kogyo Seiyaku Co., Ltd. "Plysurf A208F")

[0080] <Acrylic compounds> Acrylic compound 1:3-phenoxybenzyl acrylate ("Light Acrylate POB-A" manufactured by Kyoeisha Chemical Co., Ltd.) Acrylic compound 2: EO-modified orthophenylphenol acrylate (Dai-ichi Kogyo Seiyaku Co., Ltd. "New Frontier OPPE (registered trademark)") Acrylic compound 3: Benzyl acrylate

[0081] Example 2-1 A dispersion was obtained by mixing predetermined raw materials according to the blending conditions shown in Table 1. Specifically, 50 parts by mass of Metal Oxide Particles 1 as metal oxide particles, 5 parts by mass of Dispersant 1 as a dispersant, and 45 parts by mass of Acrylic Compound 1 as an acrylic compound were blended and mixed to obtain a dispersion. Note that the blending amounts of the metal oxide particles and dispersant shown above and in Table 1 are amounts converted to solid content, and do not include the amount of volatile matter such as solvent.

[0082] (Example 2-2) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that metal oxide particles 2 were used instead of metal oxide particles 1.

[0083] (Example 2-3) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that metal oxide particles 3 were used instead of metal oxide particles 1.

[0084] (Examples 2-4) A dispersion was obtained in the same manner as in Example 2-1, except that the amount of metal oxide particles 1 was changed to 55 parts by mass and the amount of acrylic compound 1 was changed to 40 parts by mass, as shown in Table 1.

[0085] (Examples 2-5) A dispersion was obtained in the same manner as in Example 2-1, except that the amount of metal oxide particles 1 was changed to 45 parts by mass and the amount of acrylic compound 1 was changed to 50 parts by mass, as shown in Table 1.

[0086] (Examples 2-6) A dispersion was obtained in the same manner as in Example 2-1, except that the amount of Dispersant 1 was changed to 2.5 parts by mass and the amount of Acrylic Compound 1 was changed to 47.5 parts by mass, as shown in Table 1.

[0087] (Examples 2-7) A dispersion was obtained in the same manner as in Example 2-1, except that the amount of Dispersant 1 was changed to 7.5 parts by mass and the amount of Acrylic Compound 1 was changed to 42.5 parts by mass, as shown in Table 1.

[0088] (Examples 2-8) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that acrylic compound 2 was used instead of acrylic compound 1.

[0089] (Examples 2-9) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that acrylic compound 3 was used instead of acrylic compound 1.

[0090] (Comparative Example 2) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that Dispersant C1 was used instead of Dispersant 1.

[0091] (Comparative Example 3) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that Dispersant C2 was used instead of Dispersant 1.

[0092] Comparative Example 4 As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that Dispersant C3 was used instead of Dispersant 1.

[0093] (Comparative Example 5) As shown in the formulation conditions in Table 1, a dispersion was obtained in the same manner as in Example 2-1, except that Dispersant C4 was used instead of Dispersant 1.

[0094] (Preparation of cured product) A coating agent was prepared by adding 3 parts by mass of Omnirad184 (IGM Resins B.V.) as a photopolymerization initiator to 100 parts by mass of the total mass of the dispersion obtained in each Example and Comparative Example. A polyethylene terephthalate film (trade name: Cosmoshine A4360, manufactured by Toyobo Engineering Co., Ltd.) was prepared as a substrate, and the coating agent was applied to this substrate with a bar coater to form a coating film with a thickness of 50 μm. Next, a high-pressure mercury lamp was used to irradiate the coating film with an accumulated 1000 mJ / cm. 2 The coating was cured by irradiating the substrate with light, forming a cured product (cured film) of the dispersion on the substrate. This gave a test specimen consisting of a laminate of the substrate and the cured product of the dispersion.

[0095] (Evaluation method) The dispersibility of the dispersions obtained in each of the Examples and Comparative Examples, the hardness and transparency of the test specimens formed using the dispersions, and the refractive index of the cured products of the dispersions were evaluated by the following procedures.

[0096] <Dispersibility of Dispersed Materials> The dispersibility of the dispersion was evaluated based on the viscosity measured with an E-type viscometer and the total light transmittance of the dispersion. The viscosity of the dispersion was measured at 25°C using a commercially available E-type viscometer (Tokyo Keiki Co., Ltd.), and the total light transmittance of the dispersion was measured using a Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd. Based on these values, the dispersion was evaluated according to the following criteria. <Evaluation Criteria> A: The viscosity of the dispersion is less than 5000 mPa·s, and the total light transmittance is 80% or more, making it extremely transparent and providing particularly excellent dispersibility. B: The viscosity of the dispersion is 5000 mPa·s or more and less than 10000 mPa·s, and the total light transmittance is 75% or more and less than 80%, so that the dispersion has high transparency and excellent dispersibility. C: The viscosity of the dispersion is 10,000 mPa·s or more, and the total light transmittance is less than 75%, so the transparency is extremely poor and the dispersibility is poor.

[0097] <Hardness of the cured product> The hardness of the cured product was evaluated based on the pencil hardness of the cured product formed on the substrate of the test specimen. The pencil hardness was measured in accordance with JIS K5600-5-4. The obtained pencil hardness value was evaluated according to the following criteria. <Evaluation Criteria> A: The pencil hardness of the cured product is less than 6B. B: The pencil hardness of the cured product is 6B or more and less than 3B. C: The pencil hardness of the cured product is 3B or more and less than HB.

[0098] <Transparency of the cured product> The transparency of the cured product was evaluated based on the haze value. The haze of the cured product was measured using a Haze Meter NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd. The measured haze value was evaluated according to the following criteria. <Evaluation Criteria> A: The haze of the cured product is less than 0.5, and the transparency is extremely high. B: The haze of the cured product is 0.5 or more and less than 1.0, and the transparency is high. C: The haze of the cured product is 1.0 or more, and the transparency is extremely poor.

[0099] <Refractive index of cured product> The refractive index of the cured product formed on the test specimen was measured using a prism coupler manufactured by Metricon Corporation. In this measurement, the refractive index was measured at a wavelength of 589 nm and evaluated according to the following criteria. The refractive index of the dispersion was measured at 25°C using an Abbe refractometer (NAR-IT, manufactured by Atago Co., Ltd.). <Evaluation Criteria> A: The refractive index of the cured product is 1.66 or more, which is high. B: The refractive index of the cured product is low, less than 1.66.

[0100] Table 1 shows the blending conditions (units: parts by mass) of the dispersions obtained in each Example and Comparative Example, as well as the above-mentioned evaluation results. Note that in the blending conditions in Table 1, blank spaces indicate that the corresponding raw material was not used.

[0101] As can be seen from Table 1, the dispersions obtained in each Example contained a dispersant for metal oxide particles containing a specific compound, and thus had excellent dispersibility of metal oxide particles. Furthermore, the dispersions obtained in the Examples were highly transparent even in the cured state, so the metal oxide particles maintained a good dispersion state. Furthermore, the cured products of the dispersions obtained in the Examples had a high refractive index.

[0102] [Table 1]

Claims

1. A dispersant used to disperse metal oxide particles, The following general formula (1) 【Chemical 1】 (In formula (1), R １ represents an alkyl group, m is a number from 2 to 7, and n is a number from 5 to 15. A dispersant for metal oxide particles, comprising a compound represented by the formula:

2. In the formula (1), R １ The dispersant for metal oxide particles according to claim 1, wherein is an alkyl group having 1 to 4 carbon atoms.

3. A dispersion comprising the dispersant for metal oxide particles according to claim 1 or 2, metal oxide particles, and an acrylic compound.

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