Ester compound, method for synthesizing ester compound, and resin composition

Abstract

The present disclosure pertains to: an ester compound that is a transesterification reactant between a polyol and a dicarboxylic acid ester having a disulfide bond and that has, in a molecule chain, a disulfide bond and has, at a terminal, a hydroxy group; a method for synthesizing said ester compound; and a resin composition containing said ester compound and a photo-radical generator.

Description

[Technical Field]

[0001] The present disclosure relates to an ester compound, a method for synthesizing the ester compound, and a resin composition. [Background technology]

[0002] Photosoftenable compositions that are softened by light irradiation are used in a variety of applications. For example, Patent Document 1 discloses an image-forming apparatus equipped with a recording member having a photosoftenable resin layer made of a photosoftenable resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-190883 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a novel ester compound having photosoftening properties, a method for synthesizing the ester compound, and a resin composition that softens upon irradiation with light. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to an ester compound that is a transesterification product of a dicarboxylic acid ester having a disulfide bond and a polyol, and that has a disulfide bond in the molecular chain and a hydroxy group at a terminal.

[0006] Another aspect of the present disclosure relates to a method for synthesizing an ester compound, which comprises subjecting a dicarboxylic acid ester having a disulfide bond to a transesterification reaction with a polyol to obtain an ester compound having a disulfide bond in the molecular chain and a hydroxy group at its terminal.

[0007] Another aspect of the present disclosure relates to a resin composition containing the ester compound and a photoradical generator. [Effects of the Invention]

[0008] According to the present disclosure, there are provided a novel ester compound having photosoftening properties, a method for synthesizing the ester compound, and a resin composition that softens upon irradiation with light. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to the following embodiments.

[0010] As used herein, "photosoftening" refers to properties such as a decrease in viscosity, a decrease in modulus of elasticity, an increase in loss tangent (tan δ), or a decrease in hardness upon exposure to light. The term "process" as used herein includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. Numerical ranges indicated using "to" in this specification indicate ranges that include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of a numerical range of another stage. In numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, individually described upper and lower limits can be arbitrarily combined.

[0011] In this specification, the content of each component in a composition means the total amount of the components in the composition unless otherwise specified, when the composition contains multiple substances corresponding to each component. Furthermore, unless otherwise specified, the exemplified materials may be used alone or in combination of two or more. "A or B" means that either A or B is contained, or both may be contained.

[0012] [Ester compounds] The ester compound according to the present embodiment is a photosoftenable resin that is a product of an ester exchange reaction between a dicarboxylic acid ester having a disulfide bond and a polyol, and that has a disulfide bond in the molecular chain and a hydroxyl group at the terminal. Such an ester compound can be obtained by an ester exchange reaction between a dicarboxylic acid ester having a disulfide bond and a polyol.

[0013] As a compound having a hydroxy group and a disulfide bond, a compound obtained by a Michael addition reaction between a thiol compound having a disulfide bond and an acrylate compound having a hydroxyl group is known. The compound having a hydroxy group and a disulfide bond obtained by the Michael addition reaction has a thioether bond derived from the thiol group. In contrast, the ester compound according to the present embodiment differs from at least the compound having a hydroxy group and a disulfide bond obtained by the Michael addition reaction in that it does not have a thioether bond. Furthermore, compared to the Michael addition reaction, the transesterification reaction makes it easier to control the molecular weight, and the target ester compound can be stably obtained.

[0014] The hydroxyl value of the ester compound may be 20 to 150 mgKOH / g, 20 to 140 mgKOH / g, or 25 to 120 mgKOH / g. The hydroxyl value can be measured in accordance with JIS K0070.

[0015] (Dicarboxylic acid ester with disulfide bond) The dicarboxylic acid ester having a disulfide bond is a compound having a disulfide bond capable of generating a thiyl radical upon irradiation with light and an alkyl ester group capable of transesterification. For example, a compound having a structure represented by the following formula (1) can be used as the dicarboxylic acid ester having a disulfide bond. R 1 -OC(=O)-R 3 -SSR 4 -C(=O)-OR 2 (1)

[0016] In formula (1), R 1 and R 2 each independently represents an alkyl group having 1 to 4 carbon atoms, and R 3 and R 4 R each independently represents an alkylene group having 1 to 10 carbon atoms. 1 and R 2 R is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group, in view of the ease with which the transesterification reaction proceeds. 3 and R 4 may be an alkylene group having 1 to 8 carbon atoms, an alkylene group having 2 to 6 carbon atoms, or an alkylene group having 2 to 4 carbon atoms.

[0017] Examples of dicarboxylic acid esters having a disulfide bond include dimethyl 3,3'-dithiopropionate, dimethyl dithiodiacetate, and dimethyl 4,4'-dithiodibutyrate. The dicarboxylic acid ester according to this embodiment may include at least one selected from the group consisting of dimethyl 3,3'-dithiopropionate, dimethyl dithiodiacetate, and dimethyl 4,4'-dithiodibutyrate.

[0018] (Polyol) The polyol can be used without any particular limitation as long as it is a compound having two or more hydroxy groups. The polyol may be a compound (diol) having two hydroxy groups. Examples of polyols include polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, polybutadiene polyols, and bisphenol A-ethylene oxide adduct diols. The polyol according to this embodiment may include at least one selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, polybutadiene polyols, and bisphenol A-ethylene oxide adduct diols.

[0019] Polyether polyols include, for example, polytetramethylene ether glycol, polyethylene glycol, and polypropylene glycol.

[0020] In the method for synthesizing an ester compound according to this embodiment, an ester compound having a disulfide bond in the molecular chain and a hydroxy group at its terminal can be obtained by a transesterification reaction between a dicarboxylic acid ester having a disulfide bond and a polyol.

[0021] The blending ratio of the dicarboxylic acid ester and the polyol when synthesizing the ester compound is preferably adjusted so that the molar ratio of the alkyl ester group in the dicarboxylic acid ester is in the range of 0.5 to 0.9 moles per mole of the hydroxy group in the polyol, which makes it easier to obtain an ester compound having a hydroxy group at its terminal, and makes it easier to adjust the proportion and molecular weight of the disulfide bond in the ester compound.

[0022] When synthesizing an ester compound, a catalyst may be used to promote the transesterification reaction. The catalyst is not particularly limited as long as it is a compound commonly used in transesterification reactions. Examples of the catalyst include titanium compounds and acetate compounds. Examples of titanium compounds include titanium tetraisopropoxide.

[0023] The temperature and time of the transesterification reaction are not particularly limited, and the temperature may be about 25 to 120° C., and the time of the transesterification reaction may be about 1 to 20 hours.

[0024] [Resin composition] The resin composition according to this embodiment contains the above-described ester compound and a photoradical generator.

[0025] (Photoradical generator) The photoradical generator may be a component that reacts with a thiyl radical generated when the resin composition is irradiated with light or a component that generates a photoinduced radical. Examples of the photoradical generator that can be used include a photoradical polymerization initiator.

[0026] Examples of photoradical generators include intramolecular cleavage-type photoradical polymerization initiators and hydrogen abstraction-type photoradical polymerization initiators. Examples of intramolecular cleavage-type photoradical polymerization initiators include benzyl ketal-based photoradical polymerization initiators; α-hydroxyacetophenone-based photoradical polymerization initiators; benzoin-based photoradical polymerization initiators; aminoacetophenone-based photoradical polymerization initiators; oxime ketone-based photoradical polymerization initiators; acylphosphine oxide-based photoradical polymerization initiators; titanocene-based photoradical polymerization initiators; S-phenyl thiobenzoate polymerization initiators; and high molecular weight derivatives thereof. Examples of hydrogen abstraction-type photoradical polymerization initiators include benzophenone-based photoradical polymerization initiators, thioxanthone-based photoradical polymerization initiators, and anthraquinone-based photoradical polymerization initiators.

[0027] The content of the photoradical generator may be 1 part by mass or more, 5 parts by mass or more, or 8 parts by mass or more, and may be 25 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less, relative to 100 parts by mass of the ester compound.

[0028] (Polyisocyanate) The resin composition according to the present embodiment may further contain a polyisocyanate. The polyisocyanate may be any compound having two or more isocyanate groups without any particular limitation. The polyisocyanate may be a compound having two isocyanate groups (diisocyanate).

[0029] Examples of polyisocyanates include aromatic isocyanates such as diphenylmethane diisocyanate (4,4'-diphenylmethane diisocyanate), dimethyldiphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and p-phenylene diisocyanate; alicyclic isocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and derivatives and polynuclear compounds derived from these isocyanates, such as isocyanurates, biurets, allophanates, uretdione, and polymerics. One type of polyisocyanate may be used alone, or two or more types may be used in combination.

[0030] The content of the polyisocyanate may be 10 parts by mass or more, 15 parts by mass or more, or 20 parts by mass or more, and may be 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass or less, relative to 100 parts by mass of the ester compound.

[0031] The resin composition may further contain other components in addition to the components described above. Examples of the other components include thermosetting resins such as epoxy resins, adhesion improvers such as coupling agents, polymerization inhibitors, light stabilizers, antifoaming agents, fillers, chain transfer agents, thixotropy-imparting agents, flame retardants, mold release agents, surfactants, lubricants, and antistatic agents. Known other components can be used. The total content of the other components may be 0 to 95 mass%, 0.01 to 50 mass%, or 0.1 to 10 mass%, based on the total amount of the resin composition.

[0032] The resin composition may be diluted with a solvent and used as a varnish. Examples of the solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; and amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone (NMP). The solvents may be used alone or in combination.

[0033] The concentration of solid components in the varnish may be 10 to 80% by mass based on the total mass of the varnish.

[0034] The resin composition can be prepared, for example, by mixing or kneading the ester compound, the photoradical generator, and any other components added as needed. Mixing and kneading can be carried out using an appropriate combination of dispersing machines such as a conventional mixer, a mortar and pestle, a three-roll mill, a ball mill, or a bead mill.

[0035] The resin composition according to the present embodiment can be formed into a film and used as a photosoftenable resin film. Alternatively, the resin composition can be formed into a block and used as a photosoftenable resin block. The method for forming the resin composition into a film or block is not particularly limited, and known methods can be used.

[0036] The resin composition according to this embodiment has the property that, upon irradiation with light, the disulfide bond (-SS-) in the ester compound is cleaved, and the compound having the disulfide bond is reduced in molecular weight and softened. The resin composition can also be softened to a liquid state. The resin composition also has the property of being easily molded into a film or block shape. By utilizing this property, the resin composition according to this embodiment can be applied, for example, to photoresist agents for photolithography, and can be used as a photosensitive resin composition or a photosensitive resin film. The photosensitive resin composition or the photosensitive resin film can be patterned by irradiation with light (exposure), and can further be developed by washing with water after irradiation with light (exposure). The resin composition according to this embodiment can be suitably used for forming a patterned film.

[0037] The resin composition according to this embodiment can also be used in a variety of applications, such as a softener or easy-removal agent for strong adhesive tapes; an adhesive for weakly adhesive or non-adhesive films; a partial softener for coating materials, adhesives, or adhesives; a partial softener for molding materials; a punchable, ultra-low elasticity film obtained by irradiating light after punching; a moisture-proofing agent; a capsule coating that softens and dissolves upon light irradiation; and a thickener that reduces viscosity upon light irradiation.

[0038] By irradiating the resin composition according to the embodiment with light, a softened resin composition can be obtained. The light used for the light irradiation is not particularly limited, and may be, for example, ultraviolet light or visible light. The wavelength of the light used for the light irradiation may be 150 to 830 nm. The light irradiation may be performed, for example, using a light irradiation device at an irradiation dose of 100 mJ / cm. 2 The irradiation can be carried out under the above conditions. The irradiation amount means the product of illuminance and irradiation time (seconds). Examples of light sources for irradiating ultraviolet light or visible light include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and LED lamps. The light irradiation may be carried out directly on the photosoftenable resin composition or through glass or the like.

[0039] The resin composition may be irradiated with light while being heated, for example, at a temperature of 40 to 200°C. [Example]

[0040] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to these examples.

[0041] [Ester compounds] Example 1 A flask equipped with a stirrer, thermometer, reflux condenser, pressure reducing equipment, and nitrogen inlet piping was prepared. 800 parts by mass of polyethylene glycol (Sanyo Chemical Industries, Ltd., trade name "PEG-400," molecular weight 400) and 238 parts by mass of dimethyl 3,3'-dithiodipropionate (Fujifilm Wako Chemical Co., Ltd.) were charged into the flask. The liquid phase was bubbled with nitrogen and the pressure was reduced to 70 kPa while stirring at 90°C for 2 hours. Next, 10 parts by mass of titanium tetraisopropoxide (Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 100°C for 5 hours while maintaining the bubbling and reduced pressure, allowing for a transesterification reaction. This resulted in the production of ester compound A (hydroxyl value: 108 mg KOH / g) having a hydroxy group and a disulfide bond.

[0042] Example 2 2000 parts by mass of polyethylene glycol (manufactured by Sanyo Chemical Industries, Ltd., trade name "PEG-2000", molecular weight 2000) and 119 parts by mass of dimethyl 3,3'-dithiodipropionate were charged into a flask similar to that used in Example 1, and the mixture was stirred at 90°C for 2 hours while bubbling nitrogen into the liquid phase and reducing the pressure to 70 kPa. Next, 22 parts by mass of titanium tetraisopropoxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 100°C for 12 hours while maintaining the bubbling and reduced pressure, to carry out an ester exchange reaction. This yielded ester compound B (hydroxyl value: 27 mgKOH / g) having a hydroxy group and a disulfide bond.

[0043] [Resin composition] Example 3 A resin composition was prepared by mixing 100 parts by mass of ester compound A and 10 parts by mass of a photoradical generator (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by IGM Resins BV, trade name "Omnirad TPO").

[0044] Example 4 A resin composition was prepared by mixing 100 parts by mass of ester compound B and 10 parts by mass of Omnirad TPO.

[0045] Example 5 A resin composition was prepared by mixing 100 parts by mass of ester compound A, 25 parts by mass of diphenylmethane diisocyanate (manufactured by Tosoh Corporation, trade name "Millionate MT"), and 13 parts by mass of Omnirad TPO, and then curing the mixture at 80°C for 24 hours.

[0046] (Comparative Example 1) Ester compound B was used as a resin composition without being mixed with other components.

[0047] (Comparative Example 2) A resin composition was prepared by mixing 100 parts by mass of polyethylene glycol (manufactured by Sanyo Chemical Industries, Ltd., trade name "PEG-2000", molecular weight 2000) and 10 parts by mass of Omnirad TPO.

[0048] The resin composition was irradiated with 2000mJ / cm at an illuminance of 100mW using a high-pressure mercury lamp. 2 The viscosity of the resin composition before and after irradiation was measured at 25° C. or 60° C. using an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1.

[0049] [Table 1]

Claims

1. A method for synthesizing an ester compound, comprising: subjecting a dicarboxylic acid ester having a disulfide bond to a transesterification reaction with a polyol to obtain an ester compound having a disulfide bond in the molecular chain and a hydroxy group at a terminal thereof; The method for synthesizing an ester compound, wherein the molar ratio of alkyl ester groups in the dicarboxylic acid ester is 0.5 to 0.9 moles per mole of hydroxy groups in the polyol.

2. A method for synthesizing an ester compound described in claim 1, wherein the transesterification reaction is carried out using a titanium compound as a catalyst.

3. A method for synthesizing an ester compound described in claim 1 or 2, wherein the hydroxyl value of the ester compound is 20 to 150 mg KOH / g.

4. The method for synthesizing an ester compound according to any one of claims 1 to 3, wherein the dicarboxylic acid ester comprises at least one selected from the group consisting of dimethyl 3,3'-dithiopropionate, dimethyl dithiodiacetate, and dimethyl 4,4'-dithiodibutyrate.

5. The method for synthesizing an ester compound according to any one of claims 1 to 4, wherein the polyol comprises at least one selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, polybutadiene polyols, and bisphenol A-ethylene oxide addition diols.

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