Gel particles and functional gel particles

Abstract

To provide a fine gel particle that allows the functionalization of the whole particle in water.SOLUTION: A fine gel particle comprises 1-99 mass% of a cyclocarbonate group-containing monomer (A), 1-99 mass% of an amide group-containing monomer (B) represented by the formula (3), and 0-20 mass% of a copolymerizable radical polymerizable monomer (C). (R2 is a hydrogen atom or a methyl group, and R3 and R4 independently represent a hydrogen atom or a C1-4 alkyl group).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to gel particles having a carbonate group and an amide group, and to functional gel particles. [Background technology]

[0002] Fine particles are used in a wide range of applications, including diagnostic agents, cosmetics, toner additives, and paints. In these fields, water-based paints are being developed from the viewpoints of safety and reducing volatile organic solvents. In the paint field, reactive polymers are used to improve the coating film properties of paints, but since highly reactive functional groups react with water during storage, it has been difficult to achieve both reactivity and storage stability. Patent Document 1 proposes particles having carbonate groups as functional groups that can react even in water, and these are used as curable paints by crosslinking with polyfunctional amines in water-based paints. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 1993-078600 Summary of the Invention [Problem to be solved by the invention]

[0004] However, these particles have a core-shell structure and only partially have reactive groups, so that when reacted with an amine, some sites remain unreacted, making it difficult to modify the entire particle. To solve these problems, gel particles that can be entirely functionalized in water are needed.

[0005] An object of the present invention is to provide gel microparticles which can be entirely functionalized in water. [Means for solving the problem]

[0006] As a result of investigations aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by gel microparticles composed of a polymer having both a cyclocarbonate group-containing monomer and an amide group-containing water-soluble acrylamide monomer in its structure.

[0007] That is, the present invention is as follows. (1) 3~50 % by mass of a cyclocarbonate group-containing monomer (A) represented by the following formula (1) or formula (2): 50~95 % by weight of an amide group-containing monomer (B) represented by the following formula (3), and Composition of 0 to 20 mass% of copolymerizable radical polymerizable monomer (C) (The total mass of the cyclocarbonate group-containing monomer (A), the amide group-containing monomer (B) and the radical polymerizable monomer (C) is taken as 100 mass%). Have The average particle size (25°C) is 50 nm or more and 20 μm or less. The gel particles are characterized by: [ka] (In formula (1) and formula (2), R 1 represents a hydrogen atom or a methyl group, A represents an alkylene group having 1 to 10 carbon atoms, X represents 0 or 1.) [ka] (In formula (3), R 2 represents a hydrogen atom or a methyl group, R 3 and R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. (2) Functional gel particles obtained by reacting the gel particles of (1) with an amine. Effect of the Invention

[0008] Since the gel particles of the present invention have cyclocarbonate groups and hydrophilic acrylamide structures, it is possible to functionalize the entire particle, and it is possible to obtain gel particles and functional gel particles that are highly monodisperse and responsive to external stimuli, such as temperature responsiveness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described. (Cyclocarbonate Group-Containing Monomer (A)) The cyclocarbonate group-containing monomer (A) is represented by the following formula (1) or formula (2). The monomer (A) may consist only of the monomer of formula (1), may consist only of the monomer of formula (2), or may consist of both the monomer of formula (1) and the monomer of formula (2). [ka]

[0010] In formula (1) and formula (2), R 1 represents a hydrogen atom or a methyl group. In addition, A represents an alkylene group having 1 to 10 carbon atoms. From the viewpoint of availability and ease of synthesis, the carbon number of A is preferably 2 or more. In addition, the carbon number of A is more preferably 8 or less, and particularly preferably 4 or less. In formula (1) and formula (2), x represents 0 or 1. From the viewpoint of availability and ease of synthesis, it is preferable that x is 0.

[0011] The cyclocarbonate group-containing monomer (A) of formula (1) or (2) has a cyclocarbonate group in the molecule, which provides a cyclocarbonate structure in the copolymer. The acrylate or methacrylate portion of the monomer (A) contributes to the polymerization reaction. The polyoxyalkylene group portion acts as a linker between the two.

[0012] To produce the monomer (A), various epoxy compounds having a (meth)acryloyl group are used as starting materials, and carbon dioxide is blown in at about 0.05 to 0.3 MPa to cause a reaction, whereby the monomer (A) can be obtained. In this case, various monomers can be used as the epoxy compound having a (meth)acryloyl group. However, since the viscosity is low, the reaction time is short, and the obtained cyclocarbonate group-containing monomer (A) has a low hue and good transparency, it is preferable to use glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexylmethyl methacrylate, etc. as the epoxy compound having a (meth)acryloyl group, and it is more preferable to use glycidyl (meth)acrylate.

[0013] The cyclocarbonate group-containing monomer (A) can be synthesized by reacting carbon dioxide with an epoxy group to form a cyclocarbonate group. The method of introducing carbon dioxide into the reaction system can be selected from pressurized conditions, blowing under normal pressure, etc., but pressurized conditions are preferred. At this time, by controlling the pressure and temperature within a certain range, the yield of the target product can be increased and the content of by-products can be kept low. In this case, the pressure is 0.05 to 0.3 MPaG, and preferably 0.1 to 0.2 MPaG. Even if the pressure is set high, exceeding 0.3 MPaG, the yield of the cyclocarbonate body does not increase, and side reactions are likely to proceed, which may increase the content of the di(meth)acrylate monomer.

[0014] The reaction temperature during synthesis varies depending on the pressure and catalyst conditions, but is in the range of 40 to 70°C, preferably in the range of 50 to 60°C. If the temperature is less than 40°C, the reaction time will be too long and unreacted raw materials will tend to remain. In addition, coloring will tend to occur. On the other hand, if the temperature exceeds 70°C, a large amount of di(meth)acrylate monomer will be contained, and problems such as gelation will tend to occur during polymerization. In addition, coloring will tend to occur.

[0015] When the total mass of monomers (A), (B) and (C) is taken as 100 mass%, the mass of the cyclocarbonate group-containing monomer (A) is 3~50 The mass of the monomer (A) is expressed as % by mass. 3 If the mass of the monomer (A) is less than 10%, the effect of the amine modification is reduced. 50 If the content exceeds 50% by mass, the water solubility decreases. The mass of the monomer (A) is preferably 50% by mass or less, and more preferably 30% by mass or less.

[0016] (Amide Group-Containing Monomer (B)) The amide group-containing monomer (B) may contain one or more monomers represented by the following formula (3). [ka]

[0017] In formula (3), R 2 represents a hydrogen atom or a methyl group. Also, R 3 , R 4 Each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. From the viewpoint of hydrophilicity, R 3 , R 4 is preferably a hydrogen atom, and R 3 , R 4 The number of carbon atoms in the alkyl group constituting R is preferably 1 to 4, more preferably 1 to 3, and particularly preferably 1 or 2. 3 is a hydrogen atom and R 4 has 1 to 4 carbon atoms, or R 3 is a hydrogen atom and R 4 is preferably an alkyl group having 1 to 3 carbon atoms, or R 3 and R 4 are each preferably an alkyl group having 1 to 2 carbon atoms.

[0018] Examples of the amide group-containing monomer include acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, Nt-butylacrylamide, and N-isopropylmethacrylamide.

[0019] When the total mass of the monomers (A), (B) and (C) is taken as 100 mass%, the mass of the amide group-containing monomer (B) is 50~95 The mass of the monomer (B) is preferably 50% by mass or more, more preferably 65% ​​by mass or more, from the viewpoint of the hydrophilicity of the copolymer. The mass of the monomer (B) is more preferably 95% by mass or less.

[0020] (Other copolymerizable monomers (C)) The other copolymerizable monomer (C) is not particularly limited as long as it is a monomer that is copolymerizable with the monomer (A) or the monomer (B), and may contain one or more types. However, (meth)acrylic acid ester monomers and aromatic vinyl compounds are preferred.

[0021] Examples of the (meth)acrylic acid ester monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, Examples of the acrylates include glyceryl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, stearyl (meth)acrylate, and ethylene oxide adducts of (meth)acrylic acid. Preferred are methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and benzyl (meth)acrylate, and more preferred are methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0022] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-ethylstyrene, m-ethylstyrene, o-ethylstyrene, t-butylstyrene, chlorostyrene, hydroxystyrene, t-butoxystyrene, vinyltoluene, and vinylnaphthalene, with styrene being preferred.

[0023] When the total mass of the monomers (A), (B) and (C) is taken as 100% by mass, the mass ratio of the monomer (C) is 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less, and may be 0% by mass, from the viewpoint of the hydrophilicity of the gel microparticles.

[0024] (Crosslinking agent) The gel particles of the present invention may contain a crosslinking agent in the process of preparing the dispersion of the gel particles, and the crosslinking agent is not particularly limited and may contain one or more kinds. As the crosslinking agent, BIS: N,N'-methylenebis(acrylamide); HMBA: N,N'-hexamethylenebis(methacrylamide); DHEA: N,N'-(1,2-dihydroxyethylene)bisacrylamide; PEG: polyethylene glycol dimethacrylate; DVB: divinylbenzene; EBA: N,N'-ethylenebis(acrylamide) is preferred.

[0025] (Initiator) There are no particular limitations on the water-soluble radical polymerization initiator, but examples include KPS: Potassium peroxodisulfate, V-50: 2,2-Azobis(2-methylpropanimidamide) Dihydrochloride, etc. are used.

[0026] (Method of producing gel particles) The gel particles can be produced, for example, by using an aqueous precipitation polymerization method. Specifically, a mixture of a monomer and a crosslinking agent is stirred, and nitrogen gas is flowed or bubbled to remove dissolved oxygen in the solution. An aqueous solution of an initiator is then added, and the internal temperature is raised to cause precipitation polymerization. After polymerization for a predetermined period of time, the mixture is cooled to room temperature to obtain gel particles. The heating temperature, heating time, polymerization time, etc. can be appropriately set depending on the composition of the monomer and the initiator used.

[0027] The average particle size (25° C.) of the gel particles of the present invention is 20 μm or less. the law of nature, It is preferably 5 μm or less. The lower limit of the average particle size (25° C.) of the gel microparticles is usually 50 nm or more from the viewpoint of production. However, the average particle size (25° C.) of the gel microparticles is measured by the average particle size Dh at 25° C. using a particle size measuring device (Zetasizer Nano S manufactured by Malvern Instruments) by the cumulant method.

[0028] (Functionalization of gel particles) The gel particles of the present invention can be functionalized, preferably with amines. Examples of functionalization include fluorescent labeling with amines having functional groups that exhibit fluorescence, crosslinking with amines having two or more amino groups, functional group conversion using amines having different functional groups such as amines and thiols, and selective adsorption of amines by utilizing a reaction with amines.

[0029] There is no particular limitation on the amine used for functionalizing the gel particles, and one or more kinds may be contained. From the viewpoint of reactivity with carbonate groups, primary or secondary amines are preferred, and primary amines are more preferred. Preferable specific examples include alkylamine compounds such as methylamine, ethylamine, propylamine, butylamine, and hexylamine; aromatic amine compounds such as benzylamine; alicyclic amine compounds such as morpholine, cyclopentylamine, and cyclohexylamine; aliphatic diamine compounds such as methylenediamine, ethylenediamine, trimethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine, N-(2-hydroxyethyl)-1,3-diaminopropane, and N-(2-hydroxyethyl)-ethylenediamine; aromatic diamine compounds such as phenylenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 4,4'-methylenebis(phenylamine), 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, and xylylenediamine; Examples of the diamine compounds include alicyclic diamine compounds such as cyclopentyldiamine, cyclohexyldiamine, 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, piperazine, 2,5-dimethylpiperazine, and isophoronediamine; and hydrazines and derivatives thereof such as hydrazine, adipic dihydrazide, sebacic dihydrazide, dodecanoic dihydrazide, and isophthalic dihydrazide.

[0030] There are no particular limitations on the conditions for functionalization, but an amine can be added to an aqueous dispersion of gel fine particles and stirred to cause a reaction between the carbonate groups and the amine for functionalization, and the temperature at this time is preferably 5 to 100° C., more preferably 20 to 80° C., from the viewpoint of reaction rate. There are no particular limitations on the amount of amine added, but from the viewpoint of efficiency of functionalization, it is preferably 0.1 to 5 mol, more preferably 0.3 to 3 mol, and even more preferably 0.5 to 2 mol, per mol of carbonate groups. EXAMPLES

[0031] The present invention will now be described more specifically with reference to examples and comparative examples. (Example of synthesis of fine particles) The following raw materials were placed in a three-neck round-bottom flask, stirred (250 rpm) using a stirrer, and heated to 70° C. under nitrogen bubbling. The mass ratio (mass %) of each raw material in each example and comparative example is shown in Table 1. Monomer (A): Formula (1): "Blenmer DOMA" (DOMA, NOF Corp.) Monomer (B): N-Isopropylacrylamide (NIPAm, Wako Pure Chemical Industries, Ltd.) Monomer (C): Methyl methacrylate Monomer (C): Styrene Crosslinker: N,N'-methylenebis(acrylamide) (BIS, Wako Pure Chemical Industries, Ltd.) MOI: Karenz MOI: 2-isocyanatoethyl methacrylate (MOI, manufactured by Showa Denko) Ion-exchanged water Next, 5 g of a 1 wt% aqueous solution of potassium peroxodisulfate (KPS, manufactured by Wako Pure Chemical Industries, Ltd.) was added to 95 g of the raw material mixture, and free radical polymerization was carried out. The reaction was carried out for 4 hours, after which the mixture was naturally cooled to room temperature and purified by centrifugation. The average particle diameter Dh of the obtained gel microparticles was measured at 25°C and 70°C using a particle size measuring device (Malvern Zetasizer Nano S) and the analysis method: cumulant method.

[0032] (Amine Modification Method) A 0.1% gel particle dispersion was prepared in a 30 ml screw tube, and ethylenediamine (Wako Pure Chemical Industries, Ltd.) was added in an equimolar amount to "Blenmar DOMA", and the mixture was stirred (250 rpm) at room temperature for 12 hours to modify the carbonate groups with amines, followed by purification by centrifugation. The modified gel particles were measured for their average particle diameters Dh at 25°C and 70°C using a particle size measuring device (Malvern Zetasizer Nano S) and the cumulant method. In Comparative Example 1, the modification operation was carried out using the same mass of ethylenediamine as in Example 1. In Comparative Examples 2 and 3, the modification operation was carried out using "Blenmar DOMA" or "Karenz MOI" and an equimolar amount of ethylenediamine, respectively, as in Example 1.

[0033] (Evaluation of temperature response) From the average particle diameter at each temperature, the expansion rate was calculated using the formula [average particle diameter Dh at 25°C] / [average particle diameter Dh at 70°C], and evaluated according to the following criteria. ◎: 1.8 or higher ○: 1.2 or more and less than 1.8 △: Less than 1.2

[0034] (Evaluation of modification of gel particles) From the average particle diameters at 25°C before and after modification, the expansion coefficient was calculated from the formula [average particle diameter after modification Dh] / [average particle diameter before modification Dh], and the quality of the modification was evaluated according to the following criteria. ◎: 1.3 or higher ○: 1.1 or more and less than 1.3 △: Less than 1.1

[0035] [Table 1]

[0036] In the examples, both the temperature responsiveness and the modifying properties were good. In particular, in Examples 1 and 4, the copolymer consisted of only the constituent units derived from the monomer (A) and the constituent units derived from the monomer (B), and no monomer (C) was used, but the temperature responsiveness was particularly good.

[0037] In Comparative Examples 1 and 2, the monomer (A) was not contained, but the modifying properties were deteriorated. In Comparative Example 3, which did not contain the monomer (B), both the temperature responsiveness and the modifying properties were poor.

Claims

1. 3 to 50 mass % of a cyclocarbonate group-containing monomer (A) represented by the following formula (1) or formula (2): 50 to 95% by mass of an amide group-containing monomer (B) represented by the following formula (3), and The gel particles have a composition of 0 to 20 mass % of a copolymerizable radically polymerizable monomer (C) (the total mass of the cyclocarbonate group-containing monomer (A), the amide group-containing monomer (B) and the radically polymerizable monomer (C) being taken as 100 mass %), and have an average particle diameter (25° C.) of 50 nm or more and 20 μm or less. 【Chemistry 1】 (In formula (1) and formula (2), R １ represents a hydrogen atom or a methyl group, A represents an alkylene group having 1 to 10 carbon atoms; X represents 0 or 1. 【Chemistry 2】 (In formula (3), R ２ represents a hydrogen atom or a methyl group, R ３ and R ４ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

2. 2. Functional gel particles, obtained by reacting the gel particles according to claim 1 with an amine.

Images