JP2010248475A - Amino resin crosslinked particle and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide amino resin crosslinked particles having low hygroscopicity and a sharp particle size distribution, and a method for producing the same. <P>SOLUTION: The amino resin crosslinked particles has a core-shell structure in which a shell layer is provided in an outer circumference of a core, comprises a condensate of an amino compound and formaldehyde, and has a coefficient of variation of particle diameter, a CV value, of 30% or less. The shell layer comprises a condensate of an amino compound (B) and formaldehyde, a ratio of a guanamine compound in the amino compound (B) of the shell layer being 10-100 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to amino resin crosslinked particles and a method for producing the same.

  The conventional production method of amino resin crosslinked particles by condensation and curing (crosslinking) reaction of amino compound and formaldehyde in aqueous medium is based on the hydrophilicity and hydrophobicity of the condensation product (precursor before curing) of amino compound and formaldehyde. The method is partially different (see, for example, Patent Documents 1 to 4).

  Of these, the first reaction method (reaction method I) is a reaction method in which a condensate (precursor before curing) of an amino compound and formaldehyde becomes hydrophilic.

  (1) A method usually applied when melamine is used alone as an amino compound or melamine is used as a main component, and a condensate obtained by conducting a condensation reaction between an amino compound and formaldehyde is dissolved in water. Therefore, it becomes a uniform system.

  (2) Next, by adding a curing catalyst (acid catalyst) to the solution containing the condensate (preferably under heating), crosslinking and precipitation occur, and amino resin particles are obtained. When a curing catalyst is added, a surfactant is added to the homogeneous solution containing the condensate for coagulation suppression and particle size suppression, and coexistence is performed.

  In the amino resin particles obtained by the reaction method I, particles having a sharp particle size distribution can be obtained. However, the amino resin particles obtained were highly hygroscopic particles. The upper limit of the particle size of the obtained monodisperse particles was about 2 μm (usually about 1 μm). When attempting to obtain particles having a larger and uniform particle size distribution, aggregation or the like occurred, making it difficult to obtain particles in a monodispersed state.

  Next, the second reaction method (reaction method II: suspension system) is a reaction method in which a condensate (precursor before curing) of an amino compound and formaldehyde becomes hydrophobic.

  (1) This method is employed when an amino compound having a highly hydrophobic crosslinking composition is used as a monomer. In this case, the condensate of the amino compound and formaldehyde becomes water-insoluble. For this reason, the solution containing a condensate will be in a heterogeneous state.

  (2) Next, a surfactant is added to the condensate-containing solution to make it emulsified, and then a curing catalyst (acid catalyst) is added (preferably under heating) to cause cross-linking, and amino resin Particles are obtained. Although the obtained amino resin particles had lower hygroscopicity than the particles obtained by the reaction method I, the particle size distribution had to be broad. Further, when the average particle size is 1 μm or less, it is difficult to control the particle size distribution.

JP 2004-99878 A JP 2000-256432 A Japanese Patent Publication No. 7-17723 Japanese Patent Laid-Open No. 52-5894

  Furthermore, in the case of Reaction Method I or Reaction Method II, when a small amount of melamine is used as an amino compound, the resulting amino resin particles are mainly composed of a condensate composition whose surface is derived from melamine. Therefore, it was found that the particles became highly hygroscopic.

  That is, in the prior art, it has been found that it is difficult to obtain amino resin particles having a sharp particle size distribution and controlled hygroscopicity.

  Accordingly, an object of the present invention is to provide amino resin crosslinked particles having low hygroscopicity and sharp particle size distribution, and a method for producing the same.

  In order to achieve the above object, one embodiment of the present invention has a core-shell structure in which a shell layer is provided on the outer periphery of a core, and has a coefficient of variation CV of a particle diameter made of a condensate of an amino compound and formaldehyde. 30% or less amino resin crosslinked particles, wherein the shell layer is composed of a condensate of an amino compound (B) and formaldehyde, and the ratio of the guanamine compound in the amino compound (B) of the shell layer is 10 to 100 mass. %, The amino resin crosslinked particles.

  In another embodiment of the present invention for achieving the above object, an amino resin particle comprising a condensate of an amino compound (A) containing 1 to 100% by mass of a melamine compound (Y) and formaldehyde is used as an aqueous medium. The shell layer composed of the amino compound (B) -formaldehyde condensate is added to the amino resin particles by adding and mixing the amino compound (B) while maintaining the temperature of the aqueous medium at 50 ° C. or higher. A method for producing crosslinked amino resin particles formed on a surface, wherein the amino compound (B) contains 10 to 100% by mass of a guanamine compound (X). Is the method.

  ADVANTAGE OF THE INVENTION According to this invention, a hygroscopic low amino resin crosslinked particle with a sharp particle size distribution and its manufacturing method can be provided. Furthermore, according to the present invention, it is possible to provide amino resin crosslinked particles having excellent solvent resistance and a sharp particle size distribution, and a method for producing the same.

  The present invention has technical characteristics in the formation technology of the shell layer for constituting the amino resin crosslinked particles.

  Hereinafter, the amino resin crosslinked particles and the production method thereof according to the present invention will be described in detail. However, the scope of the present invention is not limited to these descriptions, and the gist of the present invention is not impaired except for the following examples. The range can be changed and implemented as appropriate.

  In this specification, “things” such as particles and shell layers are defined (specified) by describing the content of amino compounds such as guanamine compound (X) and melamine compound (Y) and examples of preferred amino compounds. ing. However, originally, in the particle state, the amino compound undergoes a condensation reaction with formaldehyde and is contained in a form different from the original amino compound. Therefore, in the present specification, when describing “things” such as particles and shell layers, the content of amino compounds and preferred amino compounds are illustrated, but in fact, structures derived from amino compounds are described. The calculation of numerical values is based on the amount of amino compound that can be identified from the structure.

  For example, “the content of the guanamine compound (X) in the total amount of amino compound in the shell layer is 10 to 100% by mass” means that “the guanamine compound (X in the total amount of amino compound specified from the structure derived from the amino compound in the shell layer) ) Content of 10 to 100% by mass. Therefore, the content of the structure derived from the guanamine compound (X) in the total structure derived from the amino compound in the shell layer is substantially 10 It means “˜100 mass%”. Hereinafter, in the present specification, the same shall be understood unless otherwise specified.

<Method for producing amino resin crosslinked particles>
In the method for producing crosslinked amino resin particles according to one aspect of the present invention, amino resin particles comprising a condensation product of an amino compound (A) containing 1 to 100% by mass of a melamine compound (Y) and formaldehyde are used as an aqueous medium. The shell layer composed of the amino compound (B) -formaldehyde condensate is formed on the surface of the amino resin particles by dispersing and adding and mixing the amino compound (B) while maintaining the temperature of the aqueous medium at 50 ° C. or higher. A method for producing crosslinked amino resin particles, wherein the amino compound (B) contains 10 to 100% by mass of a guanamine compound (X). It is. In the present invention, the ratio (%) of the guanamine compound (X) and the melamine compound (Y) in the amino compounds (A) and (B) is “mass%” unless otherwise specified.

  The guanamine compound (X) is preferably selected from guanamines such as benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, cyclohexenecarboguanamine, acetoguanamine, norbornenecarboguanamine, and spiroguanamine. One or more selected, and particularly preferably benzoguanamine. The melamine compound (Y) is preferably melamine or a compound represented by the following general formula (1), particularly preferably melamine.

(In the formula, R represents a hydrogen atom or an alkyl group which may have a substituent, and at least one of them is an alkyl group which may have a substituent. Each R may be the same or different. May be.)
Preferred R is a hydrogen atom or a hydroxyalkyl group.

  The production method of the present invention can provide a method for producing amino resin crosslinked particles having low hygroscopicity and a sharp particle size distribution. That is, by this manufacturing method, a shell layer having a structure derived from the amino compound (B) composition in the additive liquid is formed on the surface of the amino resin particles, and non-hygroscopic particles are obtained. In addition, the particle size distribution of the core located inside is sharp and the formation of the shell layer of each particle occurs evenly, so the particle size distribution of the finally obtained amino resin crosslinked particles is also sharp.

  In the method for producing amino resin crosslinked particles of the present invention (in the case of producing amino resin particles as a core, including a step of forming a shell layer), when formaldehyde is used as a raw material, preferably an aqueous formaldehyde solution (formalin) It is subjected to the reaction in the form. Moreover, what generate | occur | produces formaldehyde, such as a trioxane and paraformaldehyde, can also be used as a raw material.

  The process for producing crosslinked amino resin particles according to the present invention comprises a step of forming a shell layer composed of an amino compound (B) -formaldehyde condensate on the surface of the amino resin particles composed of the amino compound (A) -formaldehyde condensate and curing the same. (Also referred to as a condensation / curing step).

  Therefore, in producing the amino resin crosslinked particles of the present invention, an essential process is a process of forming a shell layer on the amino resin particles and curing, but a heat treatment process (heating process) for increasing the degree of crosslinking. It is desirable to do.

  Moreover, the method for producing the amino resin particles as the core is not particularly limited, and is arbitrary (the existing production method can be used), but is produced by the first and second production methods described later. The second production method with a uniform particle diameter is particularly preferably employed.

  Therefore, the important steps in the method for producing amino resin crosslinked particles of the present invention are as follows.

  1) Amino resin particle production method (step): Although not particularly limited, the first and second production methods (steps) described below are preferred embodiments, and particularly the second production method (step). Is more preferred.

  However, in any method, in order to provide a process of forming a shell layer and curing, a heat treatment process for increasing the degree of crosslinking can be performed at the core particle stage, but the core particle is cured. Particles (dispersion liquid) that have been subjected to the stage of curing by adding a catalyst are preferred.

2) Step of forming a shell layer and curing: This is the most important and essential step. This will be described in detail below.

  3) Heat treatment step for increasing the degree of crosslinking: Although not essential, this is a preferred embodiment.

  The above-mentioned 1) 1st and 2nd production process steps ⇒ 2) step ⇒ 3) step is a preferred production method for producing the amino resin crosslinked particles of the present invention. The method used is a more preferable method.

4) Other steps a) Method of processing the amino resin crosslinked particles obtained above into a powder form, a solvent dispersion form, or a resin composition form (separation step, pulverization classification step, heating solvent replacement method) The powdering method and the like are not particularly limited, and conventionally known methods can be used.

  However, the pulverization classification process and the powdering method (powdering process) are preferably performed in an atmosphere (dry atmosphere) in consideration of moisture absorption.

  b) The neutralization step is not essential, and may be performed as necessary, for example, when sulfuric acid having high acid strength is used as the curing catalyst.

  c) A coloring process, which is a process necessary for forming colored particles such as a colored spacer, may be performed as necessary.

  Hereinafter, with respect to the method for producing crosslinked amino resin particles according to the present invention, the step 2) of forming and curing the shell layer, the step 3) of heat treatment for increasing the degree of cross-linking, and finally the step 1 above are optional steps. The preferred production method (process) of the amino resin particles is described in order.

[I] Step (condensation / curing step) for forming and curing the shell layer of 2) The condensation / curing step is an aqueous system in which amino resin particles comprising the amino compound (A) -formaldehyde condensate are dispersed. The amino compound (B) and formaldehyde are subjected to a condensation reaction and a curing reaction by adding and mixing the amino compound (B) while maintaining the medium at 50 ° C. or higher, and the amino compound (B)- A formaldehyde condensate is grown to form a shell layer made of the condensate.

  In this condensation / curing step, in addition to the amino compound (B), formaldehyde (formalin), a curing catalyst, a surfactant and the like are added in an appropriate amount in a timely manner in the aqueous medium in which the amino resin particles are dispersed. desirable. Therefore, in the following description of the manufacturing method, embodiments using these will be described in detail. However, in the production method of the present invention, such a production method can be sufficiently applied as long as a desired shell layer can be formed without using formaldehyde (formalin), a curing catalyst, or a surfactant in the above step. Needless to say. Furthermore, inorganic particles and phenols may be added as appropriate in order to obtain a preferred embodiment that further suppresses the hygroscopicity of the amino resin crosslinked particles obtained by the production method of the present invention.

  Hereinafter, each constituent requirement of the condensation / curing step will be described in detail.

(1) Amino resin particles The amino resin particles used in this step are composed of a condensate of an amino compound (A) and formaldehyde, and the amino compound (A) has a melamine compound (Y) ratio of 1 to 100 mass. %. By using amino resin particles having the above configuration (hereinafter also referred to as cores or core particles), the average particle size can be reduced. Further, the coefficient of variation CV of the particle diameter of amino resin particles can be limited to 30% or less, and amino resin particles having a sharp particle size distribution can be obtained.

  If the ratio of the melamine compound (Y) in the amino compound (A) is out of the above range, for example, coarse particles may be generated. The proportion of the melamine compound (Y) in the amino compound (A) is preferably 80% or more, more preferably 90% or more, since the particle size distribution can be suppressed sharply. On the other hand, the ratio of the melamine compound (Y) in the amino compound (A) is preferably 95% by mass or more, more preferably 100% by mass in that the average particle diameter can be easily controlled in the submicron region.

  When the proportion of the melamine compound (Y) in the amino compound (A) is other than 100%, the amino compound (A) other than the melamine compound (Y) is particularly limited as long as it is a compound having an amino group in the molecule. However, from the viewpoint of excellent moisture resistance of the resulting amino resin crosslinked particles, a compound having two or more amino groups in the molecule is preferable, and a polyfunctional amino compound having a triazine ring is more preferable.

  Examples of polyfunctional amino compounds having a triazine ring include guanamines such as benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, cyclohexenecarboguanamine, acetoguanamine, norbornenecarboguanamine, and spiroguanamine. In addition to at least one compound selected from (guanamine compound (X)), diaminotriazine compounds represented by the following general formulas (2) and (3) are preferable, and guanamine compound (X) is particularly preferable.

  General formula (2) is

(In the formula, R ¹ represents a hydrocarbon group having 1 to 2 carbon atoms which is a linear structure or a structure having a side chain.)
It is a diaminotriazine compound represented by these.

  General formula (3) is

(In the formula, R ² represents a hydrocarbon group having 1 to 8 carbon atoms which is any one of a linear structure, a structure having a side chain, a structure having an aromatic ring, and a structure having an alicyclic ring. And the structure having an alicyclic ring may be a structure having a side chain and / or a structure having a substituent.)
It is a diaminotriazine compound represented by these.

  As an amino compound (A), the amino compound combined with a melamine compound (Y) may be 1 type, but may use 2 or more types together.

  The average particle diameter d of the amino resin particles used in the production method of the present invention is preferably 0.01 to 5 μm. Within the above range, for example, particles that are particularly excellent in light diffusing performance when used as a light diffusing member using amino resin crosslinked particles obtained by the production method of the present invention and a binder resin are obtained. For the same reason, the average particle diameter of the amino resin particles is more preferably 0.05 μm or more, more preferably 0.08 μm or more, and particularly preferably 0.18 μm or more. On the other hand, from the viewpoint of the CV value being in a more preferable range, the upper limit of the average particle diameter d is preferably 3 μm or less, more preferably 1 μm or less, more preferably 0.5 μm or less, particularly preferably. 0.3 μm or less. In the present invention, the average particle diameter d of the amino resin particles is obtained by taking an SEM photograph so that the total number of particles is about 200, and the diameter of 100 particles randomly selected from the photograph is calipered. The number average value is taken as the average particle diameter. Since the particles are substantially spherical, the maximum length of the particles (cross section) of the photographed photograph is measured and taken as the diameter.

(2) Aqueous medium The aqueous medium in which the amino resin particles used in this step can be dispersed is not particularly limited, and examples thereof include water and alcohols.

  The concentration of the amino resin particles in the aqueous medium (that is, the solid content concentration) is not particularly limited, but is preferably adjusted to be in the range of 3 to 25% by mass. By making the concentration of the amino resin particles 3% by mass or more, it is excellent in that the productivity of the resulting amino resin crosslinked particles can be improved. On the other hand, when the concentration of amino resin particles is 25% by mass or less, enlargement of the resulting amino resin crosslinked particles and aggregation of particles can be effectively prevented, and amino resin crosslinked particles having a narrow particle size distribution can be obtained. it can.

  When the amino resin particles (core particles) are produced using an aqueous medium and the amino resin particles are dispersed in the aqueous medium, the concentration of the amino resin particles in the aqueous medium (solid If necessary, an aqueous medium may be further added so that the partial concentration) falls within the above range. In order to mix and disperse the amino resin particles in the aqueous medium, it is only necessary to mix and disperse using a general stirring means. For example, a disk turbine, a fan turbine, a Faudler type, a propeller type, a multistage blade, etc. Examples include a method of stirring using a stirring blade. These stirring methods can also be applied as they are to the stirring of the reaction liquid during the curing (crosslinking) reaction described later.

(3) Amino compound (B)
In this step, the amino compound (B) to be added to and mixed with the aqueous medium (maintained at 50 ° C. or higher) in which the amino resin particles are dispersed requires the guanamine compound (X) as an essential component and the amino acid of the guanamine compound (X). The ratio in a compound (B) is 10-100 mass%. By adopting such a structure, the hydrophobicity (hydrophobicity) of the shell layer formed and cured by this process is high, and the hygroscopicity (moisture and saturated moisture absorption) of the particles can be reduced. It is possible to make the dispersibility and the like excellent.

  That is, if the ratio of the guanamine compound (X) in the amino compound (B) is out of the above range, for example, the effect of suppressing the hygroscopicity of the particles may be insufficient. The proportion of the guanamine compound (X) in the amino compound (B) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, still more preferably 90% by mass or more, particularly preferably. Is 95% by mass or more, most preferably 100% by mass.

  When the ratio of the guanamine compound (X) in the amino compound (B) is other than 100% by mass, the amino compound (B) other than the guanamine compound (X) is the guanamine compound (X) among the amino compounds described above. Other amino compounds such as melamine, melamine compounds such as compounds represented by the general formula (1); diaminotriazine compounds represented by the above general formulas (2) and (3) can be preferably used. Although the amino compound combined with a guanamine compound (X) may be 1 type, you may use 2 or more types together.

  More preferably, the amino compound used in addition to the guanamine compound (X) in the amino compound (B) is preferably a melamine compound (Y), and the ratio of the melamine compound (Y) in the amino compound (B) is from 0 to 90. It is preferable that it is mass%. By adopting such a configuration, the shell layer formed and cured by this process has excellent affinity with the resin, the hydrophobicity (hydrophobization degree) of the shell layer is high, and the hygroscopicity (water content and saturated moisture absorption) of the particles. Can be lowered. Of the melamine compounds (Y) used as the amino compound (B), melamine is particularly preferable.

  When the ratio of the melamine compound (Y) in the amino compound (B) exceeds 90% by mass, for example, the hygroscopicity suppressing effect and the hydrophobicity improving effect may be insufficient. The proportion of the melamine compound (Y) in the amino compound (B) is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, because of its excellent hygroscopicity suppressing effect. Preferably it is 10 mass% or less, Especially preferably, it is 5 mass% or less, Most preferably, it is 0 mass%.

  Further, the shell layer (the guanamine compound (X) is 10 to 100% by mass) in the amino resin crosslinked particles can be separately defined by the contents (requirements) of the following 1) and 2) which can be analyzed even in a particle state.

  1) Definition of the amount of substituents in the guanamine compound (X) (phenyl group for benzoguanamine, methyl group for acetoguanamine) in mass% included in the shell layer.

  Preferably, the content of the substituent with respect to the shell layer is preferably 20% by mass or more, and more preferably 25% by mass or more. Moreover, it is preferable that it is 40 mass% or less, and it is more preferable that it is 35 mass% or less.

  The substituent in the guanamine compound (X) is preferably a phenyl group. Therefore, the content of the phenyl group in the shell layer is preferably 20% by mass or more, and more preferably 25% by mass or more. Moreover, it is preferable that it is 40 mass% or less, and it is more preferable that it is 35 mass% or less.

  The content of the substituent and phenyl group in the guanamine compound (X) is, for example, by measuring the ratio of the absorption intensity attributed to the substituent and phenyl group to the absorption intensity attributed to the triazine skeleton in the FT-IR method, Alternatively, it can be confirmed by measuring the area ratio of the C peak (chemical shift) derived from the triazine skeleton and the C peak (chemical shift) derived from the substituent and the phenyl group in the solid C-NMR method.

  2) In the preferred shell layer in the amino resin crosslinked particles, the ratio of the structure derived from the guanamine compound (X) to the structure derived from the amino compound is preferably 10 to 100% by mass, but the structure derived from the amino compound is triazine. It preferably has a structure derived from an amino compound having a ring.

  Regarding the content of the substituent derived from the guanamine compound (X) in the shell layer, the ratio of the triazine ring content to the content of the triazine ring is preferably 0.8 or more, and more preferably 0.9 or more. More preferably. A preferred upper limit is 1. Particularly preferably, the content ratio of the phenyl group to the triazine ring is within the above range.

  The content ratio of the substituent to the triazine skeleton can be confirmed by the FT-IR method or the solid C-NMR method.

  Moreover, as an amino compound other than the guanamine compound (X) used in the amino resin crosslinked particles according to the present invention, the melamine compound (Y) is preferably essential, and the guanamine compound (X) and the melamine compound (Y). It is preferable that the ratio of the guanamine compound (X) to the total amount is 5.0% by mass or more because it becomes easy to obtain particles with suppressed hygroscopicity. This ratio is more preferably 7.5% by mass or more, further preferably 30% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass or more. On the other hand, from the viewpoint of excellent solvent resistance of the amino resin crosslinked particles, the ratio of the guanamine compound (X) to the total amount of the guanamine compound (X) and the melamine compound (Y) is preferably 95% by mass or less. Is 90 mass% or less.

  Furthermore, the amino resin-crosslinked particles according to the present invention preferably have a structure derived from an amino compound consisting of a structure derived from a guanamine compound (X) or a structure derived from a guanamine compound (X) and a structure derived from a melamine compound (Y). . That is, it is preferable that the amino compound which is a raw material of the amino resin constituting the amino resin crosslinked particles of the present invention is composed of only the guanamine compound (X) or the guanamine compound (X) and the melamine compound (Y).

  The amount of the amino compound (B) used is preferably in the range of 10 to 1000 parts by mass, more preferably 25 to 700 parts by mass, and even more preferably 50 to 500 parts per 100 parts by mass of the amino resin particles (core). It is the range of mass parts. If it is 10 parts by mass or more, it is easy to form a shell layer excellent in the effect of suppressing hygroscopicity, and if it is 1000 parts by mass or less, particles with particularly sharp particle size distribution are likely to be obtained.

(4) Formaldehyde The content of formaldehyde required in this step is 1 for the molar ratio of formaldehyde / amino compound (B) in any of the following (7) (i) and (ii) added and mixed forms. .5-6, more preferably in the range of 2-4. By setting it within this range, the monomer crosslinking reaction can be promoted, and amino resin crosslinked particles having a narrow particle size distribution can be obtained. If the molar ratio is less than 1.5, the crosslinking density in the particles is insufficient and the solvent resistance becomes insufficient, and the unreacted amino compound (B) or the amino compound liberated without being taken into the shell layer (B ) And formaldehyde condensate may increase, and a stable suspension of amino resin crosslinked particles may not be obtained. On the other hand, if the content of formaldehyde exceeds 6 in terms of the molar ratio of formaldehyde / amino compound (B), the particle size distribution tends to be broad, a large amount of methylolated product is generated, and the moisture resistance of the particles is lowered. In addition, the amount of residual formaldehyde in the particles increases, which may cause safety problems. Unnecessary foaming may occur in the suspension, or the physical properties of the amino resin crosslinked particles finally obtained may be adversely affected. There is.

  In addition, in the case of the additive mixture form of (i) below (7), the amino resin particles obtained by adding excessive formaldehyde in the aqueous medium at the stage of producing amino resin particles (core particles) Formaldehyde can be contained in advance in the dispersed aqueous medium. In this case, if necessary, formaldehyde is further added to any one of the following (7) (i) and (ii) so that the content of formaldehyde in the aqueous medium is within the above range. To add. However, at the stage of producing amino resin particles (core particles), if the amount of formaldehyde required in this step is excessively added, it is not necessary to add formaldehyde in this step. .

(5) Surfactant The surfactant used in this step is used for the purpose of suppressing secondary aggregation and coalescence of amino resin crosslinked particles obtained after the shell formation reaction process.

  The surfactant that can be used in this step is not particularly limited, and examples thereof include all anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. An activator can be used. From the viewpoint of the dispersion stability of the particles in the condensation or curing reaction, an anionic surfactant, a nonionic surfactant or a mixture thereof is preferable.

  Examples of the anionic surfactant include alkali metal alkyl sulfates such as sodium dodecyl sulfate and potassium dodecyl sulfate; ammonium alkyl sulfates such as ammonium dodecyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium Sulfolicinoates; Alkyl sulfonates such as alkali metal salts of sulfonated paraffins, ammonium salts of sulfonated paraffins; Fatty acid salts such as sodium laurate, triethanolamine oleate, triethanolamine abiates; Sodium dodecyl Alkyl aryl sulfonates such as benzene sulfonate, alkali metal sulfate of alkali phenol hydroxyethylene; Le naphthalene sulfonate; naphthalenesulfonic acid-formaldehyde condensates; dialkyl sulfosuccinate, polyoxyethylene alkyl sulphates salts; polyoxyethylene alkylaryl sulphates salts can be used.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ether; polyoxyethylene alkyl aryl ether; sorbitan fatty acid ester; polyoxyethylene sorbitan fatty acid ester; fatty acid monoglyceride such as monolaurate of glycerol; Propylene copolymers; condensation products of ethylene oxide and aliphatic amines, amides or acids can be used.

  As said cationic surfactant, a quaternary ammonium salt etc. can be used, for example.

  As the amphoteric surfactant, for example, alkylbetaine can be used.

  The amount of the surfactant used is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the amino resin particles. If the amount is less than 0.01 parts by mass, a stable suspension of amino resin crosslinked particles may not be obtained. If the amount is more than 10 parts by mass, unnecessary foaming may occur in the suspension. May adversely affect the physical properties of the resulting amino resin crosslinked particles.

(6) Curing catalyst The curing catalyst used in this step is a particle growth (shell layer formation) by a curing (crosslinking) reaction on the surface of the amino resin particles to form amino resin crosslinked particles (specifically, amino resin crosslinked). Used to obtain a suspension of particles).

  An acid catalyst is suitable as the curing catalyst. Examples of the acid catalyst include mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid; ammonium salts of these mineral acids; sulfamic acids; sulfonic acids such as benzenesulfonic acid, paratoluenesulfonic acid and dodecylbenzenesulfonic acid; phthalic acid and benzoic acid Any of organic acids such as acid, acetic acid, propionic acid and salicylic acid can be used. These may be used alone or in combination of two or more.

  Of the acid catalysts exemplified above, a mineral acid is preferable from the viewpoint of improving the curing rate, and sulfuric acid is more preferable from the viewpoint of excellent corrosiveness to equipment, safety when using a mineral acid, and the like. When sulfuric acid is used as the acid catalyst, the amino resin crosslinked particles finally obtained are superior in that they do not discolor or have higher solvent resistance than when dodecylbenzenesulfonic acid is used.

  On the other hand, among the acid catalysts exemplified above, an alkyl having 10 to 18 carbon atoms is used in this step, which exhibits a unique surface activity for the particles and is excellent in producing a stable suspension of amino resin crosslinked particles. It is preferable to use an alkylbenzenesulfonic acid having a group. Examples thereof include decyl benzene sulfonic acid, dodecyl benzene sulfonic acid, tetradecyl benzene sulfonic acid, hexadecyl benzene sulfonic acid, octadecyl benzene sulfonic acid, and the like.

  It is preferable that the usage-amount of the said curing catalyst is 0.1-20 mass parts with respect to 100 mass parts of said amino resin particles, More preferably, it is 0.5-10 mass parts, More preferably, it is 1-10. Part by mass. The same applies when the alkylbenzenesulfonic acid having an alkyl group having 10 to 18 carbon atoms is used.

  When the amount of the curing catalyst used is less than 0.1 parts by mass, it may take a long time to form a shell layer by condensation curing or curing may be insufficient. On the other hand, when the amount exceeds 20 parts by mass, the curing catalyst is distributed more than necessary in the amino resin crosslinked particles in the generated suspension, and as a result, the amino resin crosslinked particles are plasticized to cause condensation curing. Aggregation and fusion between particles are likely to occur during the formation of the shell layer, and it may be difficult to finally obtain amino resin crosslinked particles having a uniform particle diameter.

  The amount of the curing catalyst used is preferably 0.0005 mol or more, more preferably 0.002 mol or more, based on 1 mol of the amino compound (B). 0.2 mol or less is preferable, and 0.1 mol or less is more preferable. Most preferably, it is 0.005-0.05 mol. When the amount of the curing catalyst used is less than 0.0005 mol relative to 1 mol of the amino compound (B), the reaction may take a long time or the curing may be insufficient. When the amount exceeds 0.2 mol, as described above, aggregation and fusion between particles are likely to occur during the formation of the shell layer, and there is a risk that it is difficult to finally obtain amino resin crosslinked particles having a uniform particle size. is there.

(7) Addition mixed form of amino compound (B) and the like to aqueous medium in which amino resin particles are dispersed Amino compound (B) used for condensation / curing reaction added to aqueous medium, curing catalyst, formaldehyde, interface The active agent is exemplified below with respect to a suitable additive mixture form. However, in this invention, what is necessary is just to be able to form a desired shell layer by condensation and hardening reaction, and it is not restrict | limited at all to the addition mixing form illustrated below.

  Specifically, formaldehyde, a surfactant, and a curing catalyst are coexisted in advance in an aqueous medium in which the amino resin particles are dispersed before adding the additive liquid containing (i) amino compound (B). Alternatively, it may be added when (ii) the amino compound (B) is added. When adding, (ii-1) you may add in the mixed state coexisted with the addition liquid containing an amino compound (B), or (ii-2) it is different from the addition liquid containing an amino compound (B). It may be added by route.

  The form (ii) is preferable for formaldehyde, the curing catalyst, and the surfactant, and the form (ii-1) is particularly preferable. This is because a predetermined concentration of the amino compound (B), formaldehyde, curing catalyst, and surfactant can be quickly dissolved or dispersed in the aqueous medium, and the condensation reaction and curing reaction can be easily controlled.

  In any of the above forms (i) and (ii), the addition liquid containing the amino compound (B) may be continuously added to the aqueous medium in which the amino resin particles are dispersed. May be added in portions. Preferably, continuous dripping is preferable. This is because the continuous one becomes uniform in the system and the distribution tends to be sharp.

  In the case of (ii-2) above, the addition of formaldehyde, surfactant, and curing catalyst added through a different route from the additive solution containing the amino compound (B) may be performed continuously, and intermittently. A fixed amount may be divided and added. Preferably, it is preferable to continuously drop an additive liquid containing formaldehyde, a surfactant, and a curing catalyst. At this time, the formaldehyde, the surfactant and the curing catalyst may be added by preparing separate additive solutions, or may be added by preparing an additive solution containing two or more of these. Particularly preferred is a form of an additive solution containing two or more.

  The addition of the curing catalyst and the amino compound (B) in the case of “added similarly” is preferably performed within the same range as the speed of the amino compound (B).

  The amino compound (B), formaldehyde, surfactant, and curing catalyst may be added as they are in any additive mixture form, but preferably as previously described, the amino compound (B), formaldehyde, An additive liquid containing a surfactant and a curing catalyst is prepared, and the amino compound (B) and / or an additive liquid containing at least one, preferably all of formaldehyde, a surfactant and a curing catalyst (amino compound) It is desirable to use an additive solution containing (B) and the like. Preferably, a liquid additive solution in which the amino compound (B) or the like is dispersed or dissolved in an aqueous medium is preferably used as the additive solution containing the amino compound (B) or the like because it is easily diffused uniformly after the addition. In the additive solution, the amino compound (B) is preferably finely dispersed with the surfactant.

  In addition, when the amino compound (B) is composed of two or more compounds of other amino compounds such as the melamine compound (Y) in addition to the guanamine compound (X), any of these added and mixed forms may be used in advance. They may be mixed and added, or may be added from separate routes. Similarly, also when using 2 or more types of surfactant together, these surfactants may be mixed and added previously or may be added from a separate path | route. Even when two or more kinds of curing catalysts are used in combination, these curing catalysts may be mixed and added in advance, or may be added from different routes.

  Further, the total addition time of the additive solution containing the amino compound (B) or the like (the time of the addition step, in the case of interruption, the time from the start of addition until the end of the addition) t (hr) has the following range. preferable.

Here, Wx: mass of the amino compound (B) to be added (kg)
Wy: Mass of amino resin particles (core particles) (kg)
By setting the total addition time t of the additive liquid containing the amino compound (B) or the like within the above range, the amino resin precursor is formed on the surface of the amino resin particles (core) dispersed in the aqueous medium (reaction liquid). After that, a layer made of amino resin can be selectively (preferentially) grown, and there is little variation in the growth thickness between individual particles, and a shell layer having a desired thickness (average value) can be formed. In addition, the outermost layer on the obtained particle surface can be a condensed composition rich in guanamine compound (X), and further reduction of hygroscopicity can be effectively achieved. Furthermore, by adjusting the total addition time t of the additive liquid containing the amino compound (B) or the like within the above range, the particle diameter fluctuations are maintained without impairing the sharp characteristics of the particle size distribution of the amino resin particles (core). It is possible to obtain amino resin crosslinked particles having a coefficient CV value of 30% or less, and more preferable CV value as described above. This is because, by adding the amino compound (B), not only on the surface of the amino resin particles (core) but also in an aqueous medium (reaction solution), a new amino resin is obtained by a condensation reaction of the amino compound (B) and formaldehyde. Amino resin particles are formed from the precursor, and most of them are adsorbed and bound to the amino resin layer that grows on the surface of the amino resin particles (core) in the vicinity. It is considered that the formation of new amino resin particles can be suppressed by controlling the total addition time t of the additive liquid containing B) or the like within the above range. The newly produced amino resin particles are, like so-called particles formed by the conventional one-step method, the outermost layer of the surface tends to be a melamine compound (Y) rich composition, and the particle size is also different. For this reason, there is a possibility that the sharpness of the particle size distribution is lowered and the hygroscopicity is suppressed. In addition, by setting t within the above range, it is advantageous in that residual unreacted monomer can be suppressed. On the other hand, when the total addition time t of the additive liquid containing the amino compound (B) or the like is less than (Wx / Wy) × 0.5 (hr), the above-described formation of new amino resin particles and particle 2 May cause secondary agglomeration. When it exceeds (Wx / Wy) × 5.0 t (hr), the production efficiency may be deteriorated. In addition, there is no restriction | limiting in particular about the specific value of Wx / Wy, The thickness of the shell layer of the amino resin crosslinked particle obtained ("t" mentioned later in the column of description of the amino resin crosslinked particle obtained), amino resin crosslinked What is necessary is just to adjust suitably so that the shell layer ratio (similarly "t / d" mentioned later) of particle | grains may become a desired value. As an example, the value of Wx / Wy is preferably 0.1 to 10, more preferably 0.25 to 7, and still more preferably 0.5 to 5. In the present condensation / curing step, it is preferable to keep the reaction solution in an appropriate temperature range and to proceed with the condensation / curing reaction while stirring / mixing with an appropriate stirring force.

(8) Condensation / curing reaction conditions of amino compound (B) and formaldehyde In this step, the aqueous medium in which amino resin particles composed of the amino compound (A) -formaldehyde condensate are dispersed is maintained at 50 ° C. or higher. The amino compound (B) and formaldehyde are subjected to a condensation reaction and a curing reaction (referred to as condensation / curing reaction) by adding and mixing the above-mentioned additives such as the amino compound (B) in an appropriate timely manner. A compound (B) -formaldehyde condensate is grown to form a shell layer made of the condensate, thereby obtaining amino resin crosslinked particles.

  The liquid temperature of the reaction liquid during the condensation / curing reaction is 50 ° C. or higher as described above. When the liquid temperature of the reaction solution is less than 50 ° C., the above reaction hardly occurs, and the target amino resin crosslinked particles are difficult to obtain. The liquid temperature of the reaction liquid is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, from the viewpoint that the above reaction can easily proceed rapidly. The upper limit of the liquid temperature of the reaction solution is preferably 300 ° C. or lower, more preferably 200 ° C. or lower. The temperature of the reaction liquid need not always be maintained at a constant temperature, and may be varied within the above range. For example, the reaction liquid may be kept under stirring from a low temperature of 50 ° C. to a high temperature of 100 ° C. or higher under pressure. This is one of the desirable modes.

  As described above, the pressure of the reaction system during the condensation / curing reaction is not particularly limited, and may be atmospheric pressure, reduced pressure, or increased pressure. From the viewpoint of safety and economy (production cost), it is preferable to carry out under atmospheric pressure. However, as described above, in the case of holding under stirring from a low temperature of 50 ° C. to a high temperature of 100 ° C. or higher under pressure. It is desirable to carry out under pressure if necessary.

  Moreover, it is preferable to hold | maintain the reaction liquid in the case of condensation and hardening reaction under stirring. As such a stirring method, it is preferable to carry out stirring under a generally known stirring device.

  The end point of the condensation / curing reaction may be determined by sampling or visual observation.

  The reaction time of the condensation / curing reaction is not particularly limited, and it may be usually maintained by heating for 1 to 12 hours. The condensation / curing reaction is completed by raising the temperature to 50 ° C. or higher and holding it for a certain period of time, but it is preferable to perform a heat treatment step for increasing the degree of crosslinking described later.

(9) Additives such as inorganic particles and phenols In the method for producing amino resin crosslinked particles, preferably in the condensation / curing reaction step after shell layer formation, in order to further suppress the hygroscopicity of the resulting amino resin crosslinked particles, Inorganic particles and phenols may be added as appropriate.

  The inorganic particles exhibit an effect of preventing the amino resin crosslinked particles from agglomerating together with a hygroscopicity suppressing effect. As the inorganic particles, metal oxide particles are preferable. As the metal oxide particles, silica, titania, alumina, zinc oxide, magnesium oxide and the like are preferably exemplified, and used in the form of powder, aqueous sol such as silica sol, alumina sol and ceria sol, or sol such as organic solvent sol. The Usually, the inorganic particles can be combined with the amino resin particles (core) in the aqueous medium, or can be combined with the amino compound (B) additive solution, and added to the shell layer to be combined and supplied to the shell layer.

Preferably the specific surface area of the inorganic particles is 10 to 400 m ² / g, more preferably 20~350m ² / g, even more preferably 30~300m ² / g. The particle diameter of the inorganic particles is 0.2 μm or less, preferably 0.1 μm or less, more preferably 0.05 μm or less. The method for adding the inorganic particles to the aqueous medium is not particularly limited, and the inorganic particles may be added as they are, or may be added in the form of a dispersion dispersed in water.

  The addition amount of the inorganic particles may be in a range in which the above-described addition effect can be exhibited, and is 1 to 30 parts by mass, preferably 2 to 28 parts by mass with respect to 100 parts by mass of the amino resin particles contained in the aqueous medium. More preferably, it is 3-25 mass parts.

  In addition, the inorganic particles are added in an inorganic medium before the condensation / curing reaction in the condensation / curing process or in the aqueous medium in the condensation / curing reaction process or in the dispersion containing the amino resin crosslinked particles obtained in the condensation / curing process. Although particles can be added, in the reaction for forming the shell layer, it is preferable to carry out the condensation / curing reaction in the state of coexisting in the aqueous medium together with the amino resin particles (core).

  A phenol means a compound having a phenolic hydroxyl group. A compound having a phenolic hydroxyl group can be added together with the amino compound (B), for example, by co-condensing the amino compound (B) with formaldehyde, thereby forming a condensate with formaldehyde, a co-condensation of the phenols with the amino compound and formaldehyde. It can be combined with the shell layer as a condensate. The phenols may be added as long as the desired hygroscopicity-suppressing effect can be achieved within a range that does not impair the effects of the present invention. The amount of the phenols used is amino compound (B) 1 It is preferable that it is 0.1-3 mol with respect to mol, More preferably, it is 0.2-1.5 mol. The phenols are not particularly limited, and examples thereof include phenol, o-ethylphenol, p-ethylphenol, mixed cresol, pn-propylphenol, o-isopropylphenol, p-isopropylphenol, and mixed isopropylphenol. O-sec-butylphenol, m-tert-butylphenol, p-tert-butylphenol, pentylphenol, p-octylphenol, p-nonylphenol, 2,3-dimethylphenol, 2,4-dimethylphenol, 2,6- Dimethylphenol, 3,4-dimethylphenol, 2,4-di-s-butylphenol, 3,5-dimethylphenol, 2,6-di-s-butylphenol, 2,6-di-t-butylphenol, 3-methyl -4-Isop Pyrphenol, 3-methyl-5-isopropylphenol, 3-methyl-6-isopropylphenol, 2-t-butyl-4-methylphenol, 3-methyl-6-t-butylphenol, 2-t-butyl-4- Compounds having a phenolic hydroxyl group such as ethylphenol; compounds having two or more phenolic hydroxyl groups in the molecule such as catechol, resorcin, biphenol, bisphenol A, bisphenol S, bisphenol F and the like.

  In addition, in the manufacturing method of amino resin crosslinked particles, as described above, the method for forming the shell layer has its characteristics (difference from the prior art), and the amino resin particles (core) The production method to be produced and the steps after the production of amino resin crosslinked particles (core-shell particles) (after reaction solution = after suspension containing amino resin crosslinked particles) will be briefly described below.

[II] Step after production of amino resin crosslinked particles (core shell particles) (after reaction solution) Step after production of amino resin crosslinked particles (core shell particles) in the condensation and curing step of [I] above (reaction solution) There are no particular restrictions on the following. That is, the method for processing the amino resin crosslinked particles obtained in the condensation / curing step into a powder form, a solvent dispersion form, or a resin composition form is not particularly limited, and a conventionally known method is used. Can be used.

  However, in the pulverizing and classifying step and the pulverizing step, it is preferable to perform in a dry atmosphere in consideration of moisture absorption.

  Moreover, a neutralization process is a process which should just be performed as needed, when a sulfuric acid with high acid strength is used for a curing catalyst.

  Further, the coloring step is not particularly limited (this step is necessary when colored particles such as colored spacers are used).

  The amino resin cross-linked particles (core-shell particles) obtained in the condensation / curing step of [I] are subjected to (1) heat treatment step and (2) neutralization step, if necessary, The form, the form of the solvent dispersion, and the method of processing into the form of the resin composition (separation step, pulverization and classification step, heated solvent replacement method, powdering method, undried powder utilization method, etc.) are taken. Here, the heated solvent replacement method refers to a method in which an aqueous medium (reaction solution, after neutralization treatment, after heat treatment, etc.) is replaced with another solvent, and the pulverization method refers to an aqueous medium (reaction solution). , After neutralization treatment, after heat treatment, etc.), and is a method of pulverizing the amino resin crosslinked particles and dispersing in a solvent. The undried powder utilization method refers to a method in which a cake obtained through a separation step from an aqueous medium (reaction solution, after neutralization treatment, after heat treatment, etc.) is dispersed in a solvent.

  Moreover, you may perform the washing | cleaning process by water and a solvent as needed after manufacturing amino resin crosslinked particle (core-shell particle).

  Hereinafter, the steps after the production of the core-shell particles including the above steps (after the reaction solution) will be described.

(I) Heat treatment step for increasing the degree of cross-linking The reaction liquid obtained by the condensation curing step is a dispersion in which the amino resin cross-linked particles of the present invention are dispersed, and the cross-linking of amino resin cross-linked particles in the dispersion is performed. In order to increase the density, it is preferable to perform a heat treatment step. The heat treatment step is a preferable step for further promoting the degree of crosslinking of the amino resin crosslinked particles in the dispersion as described above, but as a result of the increased degree of crosslinking, the hygroscopicity is suppressed and the heat resistance is improved. The effect that solvent resistance becomes high is acquired.

  Therefore, in the heat treatment step, it is preferable to perform heat treatment at a higher temperature in order to further increase the degree of crosslinking. From this point of view, the heat treatment step may be performed by autoclaving in the state of a dispersion such as (a) a reaction liquid of amino resin crosslinked particles before the separation step, or (b) from the dispersion through the separation step. The isolated amino resin crosslinked particles may be heat-treated in the gas phase. The heat treatment (b) can be performed in a heating step (drying step) described later. The heat treatment time at this time is about 30 minutes to 10 hours.

  In the autoclave treatment (a), it is preferable to perform a heat treatment step of heating at 100 to 300 ° C. in a dispersion state. By performing the autoclave treatment in the above temperature range, condensation crosslinking in the amino resin crosslinked particles can be further advanced to obtain amino resin crosslinked particles having a high crosslinking density. The autoclave treatment time of (a) is not particularly limited. When the autoclave treatment temperature is lower than 100 ° C., the autoclave treatment alone cannot sufficiently proceed with condensation / crosslinking in the amino resin crosslinked particles, and the hygroscopicity suppressing effect of the amino resin crosslinked particles is insufficient. The solvent resistance and heat resistance may not be improved. If the temperature exceeds 300 ° C., the pressure is high and uneconomical, and the resulting amino resin crosslinked particles may be discolored. The autoclave treatment (a) is applicable as long as it is in a dispersion state. Specifically, it can be applied to the reaction solution after the condensation / curing step, the dispersion after the neutralization step, the dispersion after the coloring step, and the like.

(Ii) Neutralization process The neutralization process is not particularly limited. The production method of the present invention is not essential. It is a good process. This is because in the case of a strong acid or strong alkali that has not been neutralized, if there is a large amount of the residue in the dry cake, the powder after drying tends to be colored, and it is required to be colorless (white) for light diffusion purposes. This is because it is not preferable. Therefore, it is preferable to neutralize the pH between 5.5 and 8.5, more preferably between 6.5 and 7.5. When the pH is less than 5.5, the acid catalyst and the alkali agent remain, so that the amino resin crosslinked particles may be discolored (for example, yellow) during the heating step or drying described later. is there. By adjusting the pH between 5.5 and 8.5 by the neutralization, amino resin crosslinked particles having excellent solvent resistance and heat resistance and no discoloration can be obtained. Further, in the case of colored amino resin crosslinked particles, the neutralization step is a preferred embodiment for obtaining vivid colored particles having an effect of suppressing yellowing and having excellent heat resistance.

  As a neutralizing agent that can be used in the neutralization step, for example, when neutralizing a strong acid such as sulfuric acid having a high acid strength used for the curing catalyst, an alkaline substance is suitable. Examples of the alkaline substance include sodium carbonate, sodium hydroxide, potassium hydroxide, and ammonia. Among them, sodium hydroxide is preferable in terms of easy handling, and an aqueous sodium hydroxide solution is preferably used. . These may be used alone or in combination of two or more. When neutralizing an alkali, an acidic substance is suitable as the neutralizing agent. Examples of the acidic substance include mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid; ammonium salts of these mineral acids; sulfamic acids; sulfonic acids such as benzenesulfonic acid, paratoluenesulfonic acid and dodecylbenzenesulfonic acid; phthalic acid and benzoic acid Carboxylic acids such as acetic acid, propionic acid and salicylic acid are preferred. In addition, when neutralization is performed, it is preferable to wash with ion-exchanged water or the like in order to remove residual strong acid, strong alkali, and salts generated by the reaction of these with a neutralizing agent. Further, even when neutralization is not performed, it is preferable to wash in the same manner in order to remove the curing catalyst, the surfactant and the like used in the reaction step.

(Iii) Method of processing into powder form, solvent dispersion form, and resin composition form In powder form, from the dispersion of amino resin crosslinked particles obtained after the condensation / curing step or after the neutralization step, It is preferable to perform a separation step of taking out the amino resin crosslinked particles. Even in the form of a solvent dispersion, it is preferable to perform a separation step in the case of a pulverization method or an undried powder utilization method.

  Examples of a method (separation method) for taking out amino resin crosslinked particles from the dispersion include a method of filtering and a method using a separator such as a centrifuge, but the method is not particularly limited. A known separation method can be used. Furthermore, you may wash | clean with water, an organic solvent, etc. After washing, draining is carried out by separation or centrifugation, and these operations may be repeated if necessary.

  In the form of powder, it is preferable to perform a heating step of heating the amino resin crosslinked particles taken out through the separation step at a temperature of 130 to 210 ° C. Even in the form of a solvent dispersion, in the case of a pulverization method, it is preferable to perform the heating step (including the heat treatment step in the gas phase of (b) above).

  By performing the heating step, moisture and organic solvent adhering to the amino resin crosslinked particles and remaining free formaldehyde can be removed. Furthermore, in the case where the autoclave treatment (a) is not performed, in this heating step, in order to further promote the condensation / crosslinking reaction in the amino resin crosslinked particles and further increase the degree of crosslinking, It is desirable to perform heat treatment (heat treatment). When the heat treatment temperature is lower than 130 ° C., condensation / crosslinking in the amino resin crosslinked particles cannot be sufficiently advanced, and the moisture absorption suppressing effect, solvent resistance, or heat resistance of the amino resin crosslinked particles is improved. When the temperature exceeds 210 ° C., the resulting amino resin crosslinked particles may be discolored. 150 degreeC or more is more preferable at the point which the effect which raises a crosslinking degree is excellent.

  The heating method in the heating step is not particularly limited, and a conventionally known heating method may be used. It is preferable to perform the said heating process until the moisture content of the amino resin crosslinked particle after pulverization becomes 3 mass% or less at least. Further, the heating time is not particularly limited.

  In the form of powder, the amino resin crosslinked particles obtained in the condensation / curing step are separated from the dispersion (reaction solution), taken out, dried (heated), and the resulting dried product is pulverized. The crushed material is classified. By this pulverization and classification step, amino resin crosslinked particles having a desired average particle size between submicron size and micron size and having a coefficient of variation CV value of particle size of 30% or less are obtained in powder form. be able to. Even in the form of a solvent dispersion, it is preferable to perform the pulverization and classification step in the case of a pulverization method.

  In the pulverization classification process, only classification may be performed, or a process of performing both pulverization and classification may be performed. When performing the pulverization and classification, classification may be performed after pulverization, or pulverization and classification may be performed simultaneously. In the pulverization / classification step, separate devices may be used for the pulverizer and the classifier, but an apparatus having both functions of pulverization and classification (pulverization classifier) can also be used. A conventionally well-known thing can be used for these apparatuses. The pressure of the dry air when pulverizing using a jet mill is preferably 0.4 mPa or more, and more preferably 0.5 mPa or more.

In the pulverization / classification step, it is desirable to use a dry gas in consideration of moisture absorption in order to form an air current in at least one treatment after the pulverization. Specifically, the moisture content of the gas used for the air flow formation, 6 g / ^{m 3} or less, preferably 4g / ^{m 3} or less, more preferably 2 g / ^{m 3} or less, especially preferably 1 g / ^{m 3} or less Is desirable. By setting the water content to 6 g / m ³ or less, as in the case of using normal air (atmosphere), some of the particles once pulverized or classified are agglomerated due to moisture absorption and become coarse particles. Can be effectively suppressed. This makes it possible to easily, reliably and effectively obtain amino resin crosslinked particles having a desired average particle size between submicron size and micron size and having a coefficient of variation CV value of particle size of 30% or less. Because. In addition, the minimum of the said water content is not specifically limited.

  The use of the dry gas in consideration of moisture absorption for forming the airflow may be at least one treatment after the pulverization, but is preferably used in all the treatments after the pulverization. The gas used for forming the airflow includes not only the gas used for the pulverizing process and the classifying process but also the gas used for particle transfer (particle transfer) between the processes.

  Since the gas used for forming the airflow has a risk of dust explosion, it is preferable to use an inert gas such as nitrogen gas having a low oxygen concentration, and the oxygen concentration is 10% by volume or less, preferably 5 volumes. % Or less, more preferably 3% by volume or less.

  As described above, classification may be performed in a wet manner as a method other than performing classification in an air stream (dry type). The wet classification can be performed by a vibrating sieve or a method described in, for example, JP-A-2001-252587 in the stage of the amino resin crosslinked particle dispersion before the heat treatment, that is, in the state of an aqueous dispersion or a solvent dispersion.

  Next, in the form of solvent dispersion, usable solvents include conventionally known organic solvents such as ketones, esters, ethers, alcohols, glycol derivatives (ethers, esters), hydrocarbons and the like. The solvent dispersion may be appropriately selected depending on the purpose of use. These may be used alone or in combination of two or more.

  When amino resin cross-linked particles are obtained in the form of a solvent dispersion by the heated solvent substitution method, another solvent having a higher boiling point is added to the aqueous medium, and the boiling point of the other solvent is equal to or higher than the boiling point of the aqueous medium. It is preferable to evaporate only the aqueous medium and disperse (substitute) the amino resin crosslinked particles in another solvent by heating at a temperature below. Here, the other solvent having a high boiling point is preferably a solvent having a boiling point of 100 ° C. or higher and in which the amino resin crosslinked particles are not dissolved or absorbed. Preferable examples include high boiling alcohols such as n-butanol and ethylene glycol. These may be used alone or in combination of two or more. From the viewpoint of dispersion stability, n-butanol is preferable.

  As the form of the solvent dispersion, the amino resin crosslinked particles can be obtained in the form of a solvent dispersion by a method (powdering method) in which the amino resin crosslinked particles in the form of powder are obtained and then dispersed in a solvent. Here, as the usable solvent, the above-mentioned organic solvents can be used, and may be appropriately selected according to the purpose of use of the solvent dispersion. These may be used alone or in combination of two or more. From the viewpoint of maintaining the moisture resistance of the powder, aliphatic hydrocarbons and aromatic hydrocarbons are preferable. For example, hexane and toluene are preferable. In order to disperse the powder in the solvent after powdering, it is necessary to disperse the powder in a dry state through a heating process, and a high-speed stirrer, homomixer, or ultrasonic disperser capable of powerful stirring is used. It is good to use.

  In the form of the solvent dispersion, instead of the heating solvent replacement method, the aqueous medium (reaction solution, after neutralization treatment, after heat treatment, etc.) is filtered and washed (separation step), and the cake is dispersed in the solvent. By the method (utilizing undried powder), amino resin crosslinked particles can be obtained in the form of a solvent dispersion. Here, as the usable solvent, the above-mentioned organic solvents can be used, but a hydrophilic solvent is preferable in that it can dissolve water remaining in the cake, and in particular, a low-boiling alcohol such as methanol or ethanol. Is preferred. These may be used alone or in combination of two or more. From the viewpoint of economy, methanol is preferable. In the above dispersion, a cake (powder) in a wet state after filtration and washing may be dispersed, so that a general stirring device such as a high-speed disper can be used.

(Iv) Coloring step The coloring step is not particularly limited. This process is not essential in the production method of the present invention, and is a process necessary for producing colored particles such as colored spacers. That is, in the production method of the present invention, in both the powder form and the solvent dispersion form, before the condensation / curing reaction in the condensation / curing step or the aqueous medium in the condensation / curing reaction process, A coloring step of adding a dye to the dispersion containing the amino resin crosslinked particles obtained in the curing step can be included.

  Amino resin particles and amino resin crosslinked particles are excellent in affinity with dyes. Therefore, the dye added in the coloring step is not particularly limited, and water-soluble dyes and oil-soluble dyes can be used, but water-soluble dyes are preferable. These dyes may be used alone or in combination of two or more. The method for adding the dye to the amino resin crosslinked particle dispersion is not particularly limited, but it is preferable to add the dye by dissolving or dispersing it in a solvent such as water.

(V) Inorganic particle addition step The inorganic particle addition step is also performed as necessary for the purpose of preventing the finally obtained amino resin crosslinked particles from being strongly aggregated, as in the coloring step. Can do.

  As an inorganic particle, the thing similar to the inorganic particle demonstrated in the shell layer formation process can be used. The preferred material, specific surface area, added amount and other aspects that the inorganic particles can take are as described above. The method for fixing the inorganic particles to the amino resin crosslinked particle surface is not particularly limited. From the viewpoint that the inorganic particles can be firmly fixed to the amino resin crosslinked particles, a dispersion of the amino resin crosslinked particles and an inorganic particle dispersion are provided. A method of mixing inorganic particles and adhering inorganic particles to amino resin crosslinked particles by heteroaggregation, or a method of using a device (device having high shearing force) that can be vigorously stirred such as a hybridization method is preferable.

(Vi) Coupling agent treatment step In the method for producing crosslinked amino resin particles of the present invention, the shell layer is formed in the above [I] in order to further suppress the hygroscopicity of the crosslinked amino resin particles obtained in the above [I]. The surface of the formed amino resin crosslinked particles may be treated with a coupling agent using a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, or the like.

  The coupling agent treatment conditions and the like may be any as long as the desired hygroscopicity suppressing effect can be exhibited as long as the effects of the present invention are not impaired. The amount of coupling agent used is the total amount of amino resin crosslinked particles. It is preferable that it is 0.1-10 mass% with respect to it, More preferably, it is 1-10 mass%.

(Vii) Washing step In the method for producing amino resin crosslinked particles of the present invention, a washing step using a washing liquid such as water or an organic solvent to further suppress the hygroscopicity of the amino resin crosslinked particles obtained in [I] above. May be performed. By performing the washing, it is possible to efficiently remove the surfactant remaining on the particle surface and suppress hygroscopicity. As the cleaning liquid, water or an organic solvent can be used as appropriate. Of these, water; alcohols such as methanol and ethanol; and a mixture thereof are preferably used.

[III] Production Method for Producing Amino Resin Particles (Core) The production method for producing amino resin particles is not particularly limited, and is a conventionally known production method such as JP-A-52-5894. The manufacturing methods described in Japanese Patent Publication Nos. 7-17723, 2000-256432, 2004-99878, and the like can be used.

  Hereinafter, the production method for obtaining the amino resin particles having the above-described configuration will be briefly described, but the production method of the present invention is not limited to the production method.

  The first production method and the second production method for producing amino resin particles are carried out by adding a curing catalyst to an amino resin precursor, which is an initial condensate of an amino compound and formaldehyde, to advance the curing reaction. In the production method, when the amino resin precursor is obtained in a state dissolved in an aqueous medium as a reaction solvent, the second production method is preferably applied, while the amino resin precursor is applied. When it is obtained in an insolubilized state, it is preferable to apply the first production method.

  In the first production method and the second production method, as the amino compound (A) used as a raw material in the resinification step for preparing the resin precursor, the above-described amino compound can be used, and among them, the triazine ring is used. The polyfunctional amino compound which has is preferable, More preferably, they are a guanamine compound (X) and a melamine compound (Y).

  Among the guanamine compounds (X), benzoguanamine is particularly preferable because it is easy to obtain the crosslinked amino resin particles of the present invention having excellent heat resistance and solvent resistance and suppressed hygroscopicity.

  Moreover, it is preferable that content with respect to the amino compound (A) total amount of the melamine compound (Y) in the amino compound and formaldehyde condensate is 1-100 mass%.

  As the melamine compound (Y), melamine and a compound represented by the following general formula (1) are preferable, and melamine is particularly preferable.

(In the formula, R represents a hydrogen atom or an alkyl group which may have a substituent, and at least one of them is an alkyl group which may have a substituent. Each R may be the same or different. May be.)
Preferred R is a hydrogen atom or a hydroxyalkyl group.

  The amino compound used in combination with the melamine compound (Y) is preferably a guanamine compound (X) from the viewpoint that amino resin particles having a uniform particle size distribution are easily obtained. For the same reason as described above, benzoguanamine is more preferable. preferable.

  Whether the amino resin precursor can be obtained in a dissolved or insoluble state in an aqueous medium as a reaction solvent affects not only the type of amino compound used and the composition of the compound used, but also the degree of condensation of the amino resin precursor. Therefore, the type of amino compound used in each production method and the boundary line of the composition cannot be strictly defined. However, in the second production method, the amino resin precursor tends to be water-soluble, so the melamine compound It is preferable that (Y) is a main component, and specifically, the ratio of the melamine compound (Y) to the total amount of the amino compound (A) is preferably 80% by mass or more, and 90% by mass or more. More preferably, it is more preferable to set it as 95 mass% or more. Especially preferably, it is 100 mass%.

  On the other hand, in the first production method, from the viewpoint of the raw material composition in which the amino resin precursor is likely to be hydrophobic, it is preferable to use a highly hydrophobic amino compound such as guanamine compound (X). It is preferable to use 20% by mass or more. Accordingly, the ratio of the melamine compound (Y) to the total amount of the amino compound (A) is preferably less than 80% by mass, more preferably less than 50% by mass, and more preferably less than 20% by mass. .

  It is preferable that the average particle diameter of the amino resin particles obtained in the first manufacturing method and the second manufacturing method is controlled within a preferable range of the above-described average particle diameter d of the core. That is, it is preferably controlled to 0.01 to 5 μm. The lower limit of the average particle diameter of the amino resin particles obtained in the first production method and the second production method is more preferably controlled to 0.05 μm or more, more preferably 0.08 μm or more, and particularly preferably. Is 0.18 μm or more. On the other hand, the upper limit is preferably limited to 3 μm or less, more preferably 1 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.3 μm or less.

  The second production method is preferred from the viewpoint that amino resin particles having a sharp particle size distribution can be easily obtained. That is, in order to make the particle size distribution of the amino resin crosslinked particles of the present invention uniform and to make the particle diameter variation coefficient within a preferable range, the second production method is preferable as a method for producing amino resin particles serving as a core.

(1) First Production Method As described above, the first production method for the amino resin particles (core) (hereinafter sometimes simply referred to as “first production method”) is the amino compound ( It is essential to obtain a dispersion containing amino resin particles by emulsifying and curing the amino resin precursor obtained by reacting A) with formaldehyde in an aqueous medium. If necessary, the amino resin particles can be separated from the aqueous medium and dried, the obtained dried product is pulverized, and the obtained pulverized product is classified to obtain amino resin particles in a powder state. .

  A first production method includes a resinification step of obtaining an amino resin precursor by reacting the amino compound (A) with formaldehyde, and emulsifying the amino resin precursor obtained by the resinification step to obtain an amino resin. An emulsifying step for obtaining an emulsion of the precursor, and a curing step for obtaining amino resin particles by carrying out a curing reaction of the amino resin precursor emulsified by adding a catalyst to the emulsion obtained by the emulsifying step. This is a method for producing amino resin particles.

  In the resinification step, an amino resin precursor as an initial condensation reaction product is obtained by reacting the amino compound (A) with formaldehyde. In reacting the amino compound (A) with formaldehyde, water is usually used as a solvent. Therefore, as a reaction form, a reaction liquid containing an amino resin precursor as an initial condensation reaction product is obtained by reacting an amino compound and formaldehyde in an aqueous medium. Methods include adding an amino compound to formaldehyde in an aqueous solution and reacting it, or adding an amino compound to an aqueous solution that can generate formaldehyde in water by adding trioxane or paraformaldehyde to water. The former method is preferred, and the former method is more preferred from the viewpoint of economy, such as the necessity of an adjustment tank for an aqueous formaldehyde solution and easy availability. In addition, it is preferable to perform resinification process under stirring by a well-known stirring apparatus etc.

  The molar ratio (amino compound (A) (mol) / formaldehyde (mol)) between the amino compound (A) and formaldehyde to be reacted in the resinification step is preferably 1 / 4.5 to 1 / 1.5. 1 / 4.0 to 1 / 1.8, more preferably 1 / 3.5 to 1/2. If the molar ratio is less than 1 / 4.5, free formaldehyde may increase, and if it exceeds 1 / 1.5, unreacted amino compound (A) may increase.

When water is used as a solvent, the amount of amino compound (A) and formaldehyde added to water, that is, the concentration of amino compound (A) and formaldehyde at the time of charging is higher as long as the reaction is not hindered. The concentration is desirable. More specifically, the viscosity in the temperature range of 60 to 98 ° C. of the reaction solution containing the amino resin precursor as a reaction product is 2 × 10 ^{−2 to} 5.5 × 10 ⁻² Pa · s (20 It is preferable that the concentration can be adjusted and controlled within the range of ~ 55 cP), and more preferably, the concentration of the amino resin precursor in the emulsion is in the range of 30 to 60% by mass in the emulsification step described later. The concentration may be such that the reaction solution can be added to the aqueous solution of the emulsifier or the emulsifier or the aqueous solution of the emulsifier can be added to the reaction solution so as to be inside.

Therefore, when the reaction liquid containing the amino resin precursor is obtained in the resinification step, the viscosity of the reaction liquid within the temperature range of 60 to 98 ° C. is 2 × 10 ^{−2 to} 5.5 × 10 ⁻² Pa. -It is preferable that it is s (20-55 cP), More preferably, it is 2.5 * 10 ^<-2 > -5.5 * 10 ^{< -2} > Pa * s (25-55 cP), More preferably, it is 3.0 * 10 < ^- >. ^{2 to} 5.5 × 10 ⁻² Pa · s (30 to 55 cP). The viscosity of the reaction solution is more preferably in the above range in the temperature range of 95 to 98 ° C.

  As the method for measuring the viscosity, a method using a viscosity measuring machine is optimal so that the progress of the reaction can be grasped in real time and the end point of the reaction can be accurately determined. As the viscometer, a vibration viscometer (manufactured by MIVI ITS Japan, product name: MIVI 6001) can be used.

By reacting the amino compound (A) with formaldehyde in water (in an aqueous medium), an amino resin precursor that is a so-called initial condensate can be obtained. The reaction temperature is preferably in the temperature range of 60 to 98 ° C, particularly preferably 95 to 98 ° C. And reaction of an amino compound (A) and formaldehyde cools this reaction liquid when the viscosity of a reaction liquid becomes in the range of 2 * 10 ^<-2 > -5.5 * 10 ^{< -2} > Pa * s. It suffices to end it by performing an operation such as. Thereby, the reaction liquid containing an amino resin precursor is obtained. The reaction time is not particularly limited.

  About the amino resin precursor obtained in the resinification step, the molar ratio of the structural unit derived from the amino compound (A) and the structural unit derived from formaldehyde constituting the amino resin precursor (structure derived from the amino compound (A)) The unit (mole) / formaldehyde-derived structural unit (mole)) is preferably from 1 / 4.5 to 1 / 1.5, more preferably from 1 / 4.0 to 1 / 1.8. 1 / 3.5 to 1/2 is even more preferable. By setting the molar ratio within the above range, particles having a narrow particle size distribution can be obtained.

  Amino resin precursors are usually soluble in organic solvents such as acetone, dioxane, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methyl ethyl ketone, toluene, and xylene. However, it is substantially insoluble in water.

In the first production method, the particle diameter of the finally obtained amino resin particles is reduced by increasing the viscosity of the reaction liquid in the resinification step for obtaining the reaction liquid containing the amino resin precursor. Can do. When the viscosity of the reaction solution is less than 2 × 10 ⁻² Pa · s, or when it exceeds 5.5 × 10 ⁻² Pa · s, the particle sizes are finally almost uniform (the particle size distribution is narrow). Amino resin particles cannot be obtained. That is, when the viscosity of the reaction solution is less than 2 × 10 ⁻² Pa · s (20 cP), the stability of the emulsion obtained in the emulsification step described later becomes poor. For this reason, when the amino resin precursor is cured in the curing step, the resulting amino resin particles may be enlarged or the particles may be aggregated. Moreover, when the stability of the emulsion is poor, the average particle size and particle size distribution of the amino resin particles may be changed. On the other hand, if the viscosity of the reaction liquid exceeds 5.5 × 10 ⁻² Pa · s (55 cP), the shearing force of a high-speed stirrer used in the emulsification process described later decreases, so the reaction liquid must be sufficiently stirred. There is a risk that it will not be possible. For this reason, there exists a possibility of becoming an amino resin particle with a wide particle size distribution. Therefore, adjusting the reaction solution in the resinification step to the above viscosity range is a preferred embodiment for obtaining the amino resin particles of the present invention.

  In the emulsification step, the amino resin precursor obtained in the resinification step is emulsified to obtain an emulsion of the amino resin precursor. For emulsification, for example, an emulsifier that can form a protective colloid is preferably used, and an emulsifier made of a water-soluble polymer that can form a protective colloid is more preferable.

  Examples of the emulsifier include polyvinyl alcohol, carboxymethyl cellulose, sodium alginate, polyacrylic acid, water-soluble polyacrylate, and polyvinyl pyrrolidone. Among the above-mentioned emulsifiers, polyvinyl alcohol is more preferable in consideration of the stability of the emulsion, interaction with the catalyst, and the like. Polyvinyl alcohol may be a completely saponified product or a partially saponified product. Moreover, the polymerization degree of polyvinyl alcohol is not particularly limited. The amount of the emulsifier used is preferably 1 to 30 parts by weight and more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the amino resin precursor obtained in the resinification step. If the amount used is outside the above range, the stability of the emulsion may be poor.

  In the emulsification step, for example, the reaction solution obtained in the resinification step is added to the aqueous solution of the emulsifier so that the concentration of the amino resin precursor (that is, the solid content concentration) is in the range of 30 to 60% by mass. Then, it is preferable to make it emulsion within the temperature range of 50-100 degreeC, More preferably, it is 60-100 degreeC, More preferably, it is 70-95 degreeC. The concentration of the aqueous solution of the emulsifier is not particularly limited as long as the concentration of the amino resin precursor can be adjusted within the above range. If the concentration of the amino resin precursor is less than 30% by mass, the productivity of the amino resin particles may be reduced, and if it exceeds 60% by mass, the resulting amino resin particles are enlarged or the particles are aggregated. There is a risk of doing so.

  As a stirring method in the emulsification step, a method using a device capable of stirring more strongly (a device having a high shearing force), for example, a high-speed stirrer, a homomixer, or a TK homomixer (Special Machine Industries, Ltd.) And high-speed disperser, Ebara Mileser (manufactured by Ebara Corporation), high-pressure homogenizer (manufactured by Izumi Food Machinery Co., Ltd.), static mixer (manufactured by Noritake Company Limited), and the like.

  In the emulsification step, it is preferable to promote emulsification of the amino resin precursor obtained in the resinification step until a predetermined particle size is reached, and the predetermined particle size is finally an amino resin having a desired particle size. What is necessary is just to set suitably so that particle | grains may be obtained. In order to obtain amino resin particles having a suitable particle size, the average particle size of the emulsion is preferably 0.1 to 20 μm, more preferably 0.5 to 20 μm, still more preferably 0.8 to 20 μm, particularly preferably. 1 to 15 μm. Specifically, the average particle size of the emulsion can be controlled by appropriately selecting the kind of the container and the stirring blade, the stirring speed, the stirring time, the emulsifying temperature, and the like.

  In the first production method, if necessary, inorganic particles are added to the emulsion obtained after the emulsification step in order to more reliably prevent the finally obtained amino resin crosslinked particles from agglomerating firmly. Can be added. The inorganic particles are the same as described in [II] above.

  In the curing step, a catalyst (specifically a curing catalyst) is added to the emulsion obtained in the above emulsification step, and the emulsified amino resin precursor is cured (the amino resin precursor is cured in an emulsion state). ) To obtain a suspension of amino resin particles.

  The catalyst (curing catalyst) is the same as that described in the section “(6) Curing catalyst” of [I] condensation / curing step. However, the amount of the catalyst used is preferably 0.1 to 5 parts by weight, more preferably 0.005 parts by weight with respect to 100 parts by weight of the amino resin precursor in the emulsion obtained by the emulsification step. 3 to 4.5 parts by weight, still more preferably 0.5 to 4.0 parts by weight. If the amount of the catalyst used exceeds 5 parts by weight, the emulsion state may be destroyed and the particles may be aggregated. If the amount is less than 0.1 parts by weight, the reaction may take a long time or be cured. May become insufficient. Similarly, the amount of the catalyst used is preferably 0.002 mol or more, more preferably 0.005 mol or more, and still more preferably with respect to 1 mol of the amino compound (A) used as the raw material compound. Is 0.01 to 0.1 mol. When the amount of the catalyst used is less than 0.002 mol with respect to 1 mol of the amino compound (A), the reaction may take a long time or the curing may be insufficient.

  The curing reaction in the curing step is preferably 15 (normal temperature) to 100 ° C., more preferably 40 to 95 ° C., even more preferably 60 to 90 ° C., and after holding for at least 1 hour, preferably under normal pressure or pressure. It is preferable to carry out at a temperature in the range of 60 to 250 ° C, more preferably 80 to 220 ° C, and still more preferably 100 to 200 ° C. If the reaction temperature of the curing reaction is less than 60 ° C., the curing does not proceed sufficiently, and the solvent resistance and heat resistance of the resulting amino resin particles may be reduced. Decomposition starts and the particles are easily yellowed.

  The reaction time for the curing reaction is preferably 0.1 to 12 hours, but is not particularly limited.

  As a stirring method in the curing step, it is preferably carried out under stirring by a generally known stirring device or the like.

  In the first production method, the curing is further performed by adding a catalyst to the emulsion obtained by the emulsification, and the addition of the catalyst is performed within 5 hours from the start of the emulsification. It is preferable to make it. Thus, by controlling the time from the start of emulsification (start of mixing of the amino resin precursor and the emulsifier) to the start of curing (at the time of addition of the catalyst) (hereinafter sometimes referred to as emulsification time) within 5 hours. Amino resin particles can be obtained.

  The emulsification time is preferably within 4 hours, more preferably within 3 hours, even more preferably within 2 hours, and even more preferably within 1 hour. When the time exceeds 5 hours, the generation amount of coarse particles (or particles) having a specific particle size or more is not preferable.

  However, the first production method can also include a coloring step of adding an aqueous solution obtained by dissolving a dye in water to an emulsion of amino resin precursor or a suspension of amino resin particles. Moreover, you may add dye further to the reaction liquid obtained at the said resinification process as a pre-stage coloring process as needed. Furthermore, the neutralization process which neutralizes the suspension containing the amino resin crosslinked particle obtained by the said hardening process can be included. The coloring process, the pre-coloring process, and the neutralization process are the same as described in [II] above.

  In the first production method, the suspension of amino resin particles obtained after the curing step or the neutralization step may be performed as described above. However, it is necessary to distribute, store or store as an intermediate product. In some cases, a separation step of removing the amino resin particles can be further included. Moreover, the process of drying (heating) the amino resin particle taken out through the isolation | separation process can be included. Further, the amino resin particles obtained through the curing reaction step are separated from the aqueous medium at the time of emulsification and dried (heated), and the obtained heat-dried product is pulverized. Finally, the obtained pulverized product is obtained. May be classified. The separation step, drying (heating) step, and pulverization / classification step are the same as described in [II] above.

(2) Second Production Method A second production method of amino resin particles (hereinafter sometimes simply referred to as “second production method”) that can be suitably used as the core of the crosslinked amino resin particles of the present invention. As described above, an amino resin precursor having a high water miscibility obtained by reacting the amino compound (A) with formaldehyde is mixed with a surfactant in an aqueous medium, and this mixture is mixed with a curing catalyst. Is added to cure, precipitate, and granulate the amino resin precursor in the aqueous medium. If necessary, the amino resin particles may be further separated from the aqueous medium and dried, the obtained dried product is pulverized, and the obtained pulverized product may be classified. However, also in the second production method, which is the production step of the core particles, particles that have been subjected to the step of curing by adding a curing catalyst as the core particles are preferable, and in the core particle step, a heat treatment step for increasing the degree of crosslinking ( It is preferable not to perform autoclave treatment or heating step).

  The amino resin particles of the present invention having a desired average particle size between submicron size and micron size, and more preferably having a variation coefficient CV value of the particle size of 30% or less are the first and second production methods. Among these, it can obtain preferably by the 2nd manufacturing method. In a preferred state of the second production method, it is easy to prepare amino resin particles having a very small particle diameter by initiating curing of the amino resin precursor in an aqueous solution state, and the average particle diameter is 0.1 to 5 μm. This is because it is easy to obtain amino resin particles that are particles having a sharp particle size distribution (variation coefficient CV value is 30% or less).

  The water miscibility of the amino resin precursor suitable for the second production method is 100% or more. The water miscibility is the degree of water affinity, and is the mass% of the amount of water added to the initial condensate until water is clouded by adding water to the amino resin precursor at 15 ° C. (hereinafter referred to as water miscibility). Measured). In the second production method, the preferred water miscibility of the amino resin precursor is 100% or more. An amino resin precursor having a water miscibility of less than 100% causes poor dispersion in an aqueous liquid containing a surfactant and forms only a non-uniform suspension having a relatively large particle size. The resulting amino resin particles are enlarged and it is difficult to obtain particles having a sharp particle size distribution.

  In the mixing step, the amino resin precursor obtained in the resinification step is mixed with a surfactant in an aqueous medium by stirring or the like to obtain a mixed solution. The surfactant is the same as described in the section “(5) Surfactant” in the [I] condensation / curing step.

  As a stirring method in the mixing step, a general stirring method may be used. For example, a stirring method using stirring blades such as a disk turbine, a fan turbine, a fiddler type, a propeller type, and a multistage blade is preferable.

  In the second production method, in order to prevent the amino resin particles finally obtained from agglomerating more firmly, if necessary, inorganic particles are added to the liquid mixture obtained after the mixing step. I can leave. Regarding the inorganic particles and the addition method thereof, the description in the first production method described above can be similarly applied.

  In the curing / particulation step, a catalyst (specifically a curing catalyst) is added to the mixed solution obtained in the mixing step, and the amino resin precursor is cured and granulated to produce amino resin particles (specifically, A suspension of amino resin particles) is obtained. The catalyst (curing catalyst) is the same as that described in the section “(6) Curing catalyst” of [I] condensation / curing step.

  The curing reaction and granulation in the curing and granulating step may be performed by adding the catalyst to the mixed solution of the amino resin precursor and maintaining the mixture at 15 to 100 ° C. with stirring. There is no restriction | limiting in particular in the addition method of the said catalyst, It can select suitably.

  The reaction time for the curing reaction is preferably 0.1 to 12 hours, but is not particularly limited. The curing reaction is generally completed by raising the temperature to 90 ° C. or higher and holding it for a certain period of time. However, curing at a high temperature is not necessarily required and can be obtained even at a low temperature in a short time. It is sufficient that the amino resin particles in the suspension are cured to such an extent that they do not swell with methanol or acetone. As a stirring method in the curing / particulating step, it is preferably carried out under stirring by a generally known stirring device.

  Also in the second production method, which is a production step of the core particles, particles that have been subjected to the step of curing by adding a curing catalyst as the core particles (the curing and granulating step) are preferable. A heat treatment step (autoclave treatment or heating step) for enhancing may be performed as necessary.

  However, the second production method also includes a coloring step of adding an aqueous solution obtained by dissolving a dye in water to a mixed solution of an amino resin precursor and a surfactant or a suspension of amino resin particles. Can do. Moreover, you may add dye further to the reaction liquid obtained at the said resinification process as a pre-stage coloring process as needed. Furthermore, the neutralization process which neutralizes the suspension containing the amino resin crosslinked particle obtained by the said hardening process can be included. The coloring process, the pre-coloring process, and the neutralization process are the same as described in [II] above.

  In the second production method, the suspension of the amino resin particles obtained after the curing / particulating step or the neutralizing step may be performed as described above, but it may be distributed as an intermediate product or stored / stored. When it is necessary to do this, a separation step of taking out the amino resin particles can be further included. Moreover, the process of drying (heating) the amino resin bridge | crosslinking particle taken out through the isolation | separation process can be included. Further, the amino resin particles obtained through the curing reaction step are separated from the aqueous medium at the time of emulsification and dried (heated), and the obtained heat-dried product is pulverized. Finally, the obtained pulverized product is obtained. May be classified. The separation step, drying (heating) step, and pulverization / classification step are the same as described in [II] above. In the second production method, the amino resin particles are separated from the suspension and taken out by removing the amino resin particles obtained by the curing / particulation from the aqueous medium during the mixing step or the curing / particulating step. It is to be separated and taken out from.

  The reaction liquids obtained by the first and second production methods are dispersions in which amino resin particles are dispersed. Further, the heat treatment step described in the method for producing amino resin crosslinked particles is performed to increase the crosslinking density. Then, it can also be subjected to a reaction for forming a shell layer, which is a process for producing amino resin crosslinked particles. Since the formation reaction activity of the shell layer of amino resin particles is high and the dispersibility of the amino resin particles as the core is excellent, the shell layer formation is easy to proceed uniformly and selectively, and various physical properties such as low moisture absorption Since excellent amino resin crosslinked particles are easily obtained, the reaction solution is preferably subjected to a shell layer forming reaction as an amino resin particle dispersion as a core.

<Amino resin crosslinked particles>
According to another aspect of the present invention, the particle diameter variation coefficient CV value is 30% or less, which has a core-shell structure in which a shell layer is provided on the outer periphery of the core, and is composed of a condensate of an amino compound and formaldehyde. Amino resin crosslinked particles, wherein the shell layer is composed of a condensate of an amino compound (B) and formaldehyde, and the ratio of the guanamine compound (X) in the amino compound (B) of the shell layer is 10 to 100% by mass. Amino resin crosslinked particles are provided. The technical scope of the present invention should be determined based on the description of the claims. For example, the technical scope of the “method for producing amino resin crosslinked particles” which is an embodiment of the present invention should not be limited by the structure and physical properties of the produced amino resin crosslinked particles. In addition, the technical scope of “amino resin crosslinked particles” which is another embodiment of the present invention is not limited to those obtained by the above-described production method, and those obtained by other production methods are also included. It can also be included.

  In the amino resin crosslinked particles according to this embodiment, preferably, the core is composed of a condensate of an amino compound (A) and formaldehyde, and the ratio of the melamine compound (Y) in the amino compound (A) is 1 to 100% by mass. It is.

  First, specific forms of the guanamine compound (X) and the melamine compound (Y) will be described.

  The guanamine compound (X) is preferably selected from guanamines such as benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, cyclohexenecarboguanamine, acetoguanamine, norbornenecarboguanamine, and spiroguanamine. One or more selected, and particularly preferably benzoguanamine.

  The melamine compound (Y) is preferably melamine or a compound represented by the following general formula (1), particularly preferably melamine.

(In the formula, R represents a hydrogen atom or an alkyl group which may have a substituent, and at least one of them is an alkyl group which may have a substituent. May be different.)
Preferred R is a hydrogen atom or a hydroxyalkyl group.

  In the amino resin crosslinked particles according to the present embodiment, the above configuration can be used to make particles with low hygroscopicity, and the particle diameter variation coefficient CV value can be limited to 30% or less. The ratio of the guanamine compound (X) in the amino compound (B) of the shell layer is 10% or more, because the content ratio of the structure derived from the guanamine compound (X) in the structure derived from the amino compound (triazine structure, etc.) It means 10% or more in terms of compound. The same applies hereinafter.

  If the ratio of the guanamine compound (X) in the amino compound (B) is out of the above range, for example, the effect of suppressing the hygroscopicity of the particles may be insufficient. The proportion of the guanamine compound (X) in the amino compound (B) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, still more preferably 90% by mass or more, particularly preferably. Is 95% by mass or more, most preferably 100% by mass.

  When the ratio of the guanamine compound (X) in the amino compound (B) is other than 100% by mass, the amino compound (B) other than the guanamine compound (X) is the guanamine compound (X) among the amino compounds described above. Other amino compounds such as melamine, melamine compounds such as compounds represented by the general formula (1); diaminotriazine compounds represented by the above general formulas (2) and (3) can be preferably used. Although the amino compound combined with a guanamine compound (X) may be 1 type, you may use 2 or more types together.

  More preferably, the amino compound used in addition to the guanamine compound (X) in the amino compound (B) is preferably a melamine compound (Y), and the ratio of the melamine compound (Y) in the amino compound (B) is from 0 to 90. It is preferable that it is mass%. By adopting such a configuration, the shell layer formed and cured by this process has excellent affinity with the resin, the hydrophobicity (hydrophobization degree) of the shell layer is high, and the hygroscopicity (water content and saturated moisture absorption) of the particles. Can be lowered. Of the melamine compounds (Y) used as the amino compound (B), melamine is particularly preferable.

  When the ratio of the melamine compound (Y) in the amino compound (B) exceeds 90% by mass, for example, the hygroscopicity suppressing effect and the hydrophobicity improving effect may be insufficient. The proportion of the melamine compound (Y) in the amino compound (B) is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, because of its excellent hygroscopicity suppressing effect. Preferably it is 10 mass% or less, Especially preferably, it is 5 mass% or less, Most preferably, it is 0 mass%.

  As described above, in the amino resin crosslinked particles according to this embodiment, by adopting the above-described configuration, it is possible to obtain particles with low hygroscopicity, and it is possible to limit the particle diameter variation coefficient CV value to 30% or less.

  As a result, it can be said that the present invention can be sufficiently applied to components and members used in various industrial products including the field of display elements such as LCDs. Specifically, including light diffusing agents for optical resins such as light diffusing plates for display elements such as LCDs, light diffusing agents for light diffusing films (diffusing transmitted light), and light diffusing agents for anti-glare films. , PET (polyethylene terephthalate) film, PEN (polyethylene naphthalate) film, PP (polypropylene) film, anti-blocking agent for various polymer films such as PE (polyethylene) film, lubricant; light diffusion used for LED lighting covers, etc. Agents; gap distance retention agents such as LCD spacer agents; base particles for conductive particles (metal plating) (suitable for anisotropic conductive films and the like); matting agents and the like, but are not limited to these It is not a thing. In particular, since the amino resin crosslinked particles of the present invention have low hygroscopicity, they can be monodispersed in the resin matrix without agglomerating between the particles, and evenly disposed on the surface of the film substrate or the like when used in the above applications Can be made. In addition, the adhesion with the binder resin and film base due to moisture absorption of the particles and the generation of voids at the interface with the binder resin and film base can be greatly suppressed and prevented, providing excellent adhesion It can also develop power. As a result, a resin molded product such as a film having high quality and excellent durability can be obtained. Furthermore, the amino resin crosslinked particles of the present invention can be made into core-shell structured particles with a sharp particle size distribution, the optical refractive index etc. can be changed between the core and the shell, and the average particle size can also be adjusted arbitrarily from submicron to micron size Since it can do, it can arrange | position uniformly as a light-diffusion agent etc. with which the particle diameter was very uniform on the surfaces, such as a film base material, for the said use, and can achieve the outstanding light-diffusion characteristic.

  Hereinafter, the preferable form of the amino resin crosslinked particles according to this embodiment will be described in more detail.

(1) Particle diameter variation coefficient CV value of amino resin crosslinked particles In the amino resin crosslinked particles according to the present embodiment, the particle diameter variation coefficient CV value is 30% or less. The coefficient of variation CV of the particle diameter of the amino resin crosslinked particles is more preferably 20% or less, still more preferably 10% or less, and particularly preferably 7% or less from the viewpoint of excellent light diffusion characteristics. In the present invention, the coefficient of variation CV of the particle diameter of the amino resin crosslinked particles is the average particle diameter D determined according to the following average particle diameter measuring method (2) and the particle diameter standard measured by the same method. Using the deviation, the following formula is used.

(2) Average particle diameter D of amino resin crosslinked particles
The preferable average particle diameter D of the amino resin crosslinked particles (core-shell particles) according to this embodiment is in the range of 0.05 to 100 μm. When the average particle diameter D is out of the range of 0.05 to 100 μm, for example, the light diffusion performance may be deteriorated when a light diffusion member is formed using amino resin crosslinked particles and a binder resin. The average particle diameter of the amino resin crosslinked particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, and further preferably 0.2 μm or more from the viewpoint of becoming a light diffusing member with high brightness. On the other hand, from the viewpoint of excellent light diffusion characteristics, the average particle diameter of the crosslinked amino resin particles of the present invention is preferably 50 μm or less, more preferably 30 μm or less, still more preferably 10 μm or less, particularly preferably 5 μm or less. 4 μm or less is preferable. In the present invention, the average particle diameter D of the amino resin crosslinked particles is obtained by taking an SEM photograph so that the total number of particles is about 200, and the diameter of 100 particles randomly selected from the photograph. Measure with a vernier caliper and use the number average value as the average particle size. Since the particles are substantially spherical, the maximum length of the particles (cross section) of the photographed photograph is measured and taken as the diameter.

(3) Thickness (average value) t of shell layer of amino resin crosslinked particles
In the amino resin crosslinked particles according to this embodiment, the thickness (average value) t of the shell layer of the particles is preferably 0.01 μm or more. When the thickness (average value) t is 0.01 μm or more, the particles tend to be hygroscopically suppressed, and the light diffusion performance when, for example, amino resin crosslinked particles and a binder resin are used as a light diffusion member. It will be excellent. The thickness (average value) t of the shell layer of the amino resin crosslinked particles of the present invention is preferably 0.02 μm or more, more preferably 0.03 μm or more, particularly preferably 0.04 μm from the viewpoint of particularly low hygroscopicity. That's it. On the other hand, the thickness is preferably as large as possible from the viewpoint of suppressing hygroscopicity, but the thickness (average value) t of the shell layer of the amino resin crosslinked particles according to this embodiment is preferably 5 μm or less from the viewpoint of excellent dispersibility. The thickness (average value) t of the shell layer of the amino resin crosslinked particles is expressed by the formula: t = (D) from the average particle diameter D (μm) of the grown particles after the shell formation and the average particle diameter d (μm) of the core. -D) / 2. Here, as D and d, values obtained by the above-described method can be used.

(4) Shell layer ratio of amino resin crosslinked particles (t / d)
The shell layer ratio (t / d) of the core particles of the amino resin crosslinked particles according to this embodiment is in the range of 0.1 to 1.5. Here, the shell layer ratio of the amino resin crosslinked particles refers to the thickness (average value) t (μm) of the shell layer / the diameter (average particle size) d (μm) of the core inside the shell layer. When the shell layer ratio is in the range of 0.1 to 1.5, the hygroscopic property is low and the dispersibility is excellent. For example, the light diffusion member using the amino resin crosslinked particles and the binder resin of the present invention can be used. Excellent light diffusion performance. The shell layer ratio of the amino resin crosslinked particles according to this embodiment is preferably 0.1 or more, more preferably 0.2 or more, and particularly preferably 0.3 or more from the viewpoint of low hygroscopicity.

(5) Overall Composition of Amino Resin Crosslinked Particles Amino resin crosslinked particles according to this embodiment are composed of a condensate of an amino compound and formaldehyde, the shell layer is composed of a condensate of amino compound (B) and formaldehyde, and an amino compound ( B) is selected from guanamine compounds (X) such as benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, cyclohexenecarboguanamine, acetoguanamine, norbornenecarboguanamine, spiroguanamine and the like. Species or two or more species are essential, and it is essential that the ratio of the guanamine compound (X) is 10 to 100% by mass with respect to the total amount of the amino compound (B).

  Furthermore, in the amino resin crosslinked particles according to this embodiment, the core is preferably composed of a condensate of an amino compound (A) and formaldehyde, but the proportion of the melamine compound (Y) in the amino compound (A) is 1 to 100% by mass. If there is, there is no restriction | limiting in particular regarding an amino compound (A).

(6) Form of amino resin cross-linked particles and preferred embodiment The form of the amino resin cross-linked particles according to the present embodiment can take the form of a powder or a solvent dispersion depending on the following usage.

  In the amino resin crosslinked particles according to the present embodiment, the following a) to c) can be taken as preferred embodiments for further suppressing hygroscopicity.

  a) Inorganic particles, and more preferably metal oxide particles such as silica, titania, alumina, zinc oxide and magnesium oxide are combined in a shell layer.

  In a preferred embodiment of a), the primary particle diameter of the metal oxide fine particles is 0.1 μm or less. More preferably, it is 0.05 micrometer or less, More preferably, it is 0.03 micrometer or less. The lower limit is preferably 0.005 μm or more.

  b) Compound having phenolic hydroxyl group, compound having two or more phenolic hydroxyl groups in the molecule (polyhydric phenols) and formaldehyde condensate, and compound, amino compound and formaldehyde cocondensate compounded in shell layer It is made up of.

  Here, the embodiment a) can be obtained by, for example, coexisting with an amino resin particle (core) in an aqueous medium in a reaction for forming a shell layer.

  The embodiment of b) can be obtained, for example, by cocondensing amino compound (B) with formaldehyde, such as adding phenols together with amino compound (B) in the reaction for forming the shell layer.

  c) The surface of the crosslinked amino resin particles of the present invention on which the shell layer has been formed is treated with a coupling agent such as a silane coupling agent, a titanate coupling agent, and an aluminum coupling agent.

(7) Characteristics of Amino Resin Crosslinked Particles As described above, the amino resin crosslinked particles according to this embodiment are characterized in that, as described above, the shell layer, that is, the surface is mainly composed of the amino compound (B) and the formaldehyde containing the guanamine compound (X). By being a condensate, non-hygroscopicity and hydrophobicity can be high, and a high refractive index can be obtained. Due to the core-shell structure (two-layer structure), it is excellent in light diffusion characteristics and solvent resistance. Due to the crosslinked particles of amino resin, it has excellent heat resistance. When the CV value is 30% or less, the particle (group) has a sharp particle size distribution.

  As a result of the amino resin crosslinked particles having the constitution of the present invention, the following properties are exhibited in addition to the above properties.

(A) Water content of particles The water content of the amino resin crosslinked particles according to the present embodiment is preferably 0.1 to 3% by mass. More preferably, it is 2.5 mass% or less, Most preferably, it is 1 mass% or less. Since it has the water content, it is excellent in dispersibility and adhesion to the binder resin.

  The moisture content of the amino resin crosslinked particles was determined by quantifying 1 g of the crushed powder (amino resin crosslinked particles) by the Karl Fischer method as described in the evaluation method of the Examples, and the percentage of the obtained moisture content was determined. The water content (% by mass). That is, the amino resin crosslinked particles of the present invention can be obtained not only in the form of powder but also in the form of a solvent dispersion. When such moisture content is determined, conventionally known methods such as filtration and centrifugation of the particles from the solvent are used. A sample obtained by isolating and evaporating the solvent is used as a sample.

(B) Saturated moisture absorption amount of particles The saturated moisture absorption amount (%) of the amino resin crosslinked particles according to this embodiment is preferably less than 10%, and more preferably 7% or less. More preferably, it is 6% or less, and particularly preferably 5% or less. Moreover, it is preferable that a lower limit is 1% or more. Since it has the above saturated moisture absorption amount, it is excellent in dispersibility in the binder resin.

  The saturated moisture absorption amount of the amino resin cross-linked particles was determined by leaving the pulverized powder (amino resin cross-linked particles) for 1 day in an atmosphere of a temperature of 30 ° C. and a humidity of 90% RH as described in the evaluation method of the examples. The water content is measured in the same manner as the water content of the amino resin crosslinked particles (a) above, and the percentage of the obtained water content is defined as the saturated moisture absorption (%).

(C) Hydrophobic degree of amino resin cross-linked particles The hydrophobized degree of the amino resin cross-linked particles according to this embodiment is preferably 10% or more, more preferably 20% or more, still more preferably 22.5% or more, particularly Preferably it is 25% or more. Since it has the above hydrophobicity, it is excellent in dispersibility in the binder resin.

  Hydrophobic degree of amino resin cross-linked particles is determined by placing 50 cc of water in a 200 cc glass beaker and floating 0.2 g of hydrophobized powder (pulverized amino resin cross-linked particles) on the stirrer. Stir gently and put a burette containing methyl alcohol in the water and gradually mix the methyl alcohol. The methyl alcohol is the total amount of water and methyl alcohol when the completely floating powder sinks. The percentage of the input amount is defined as the degree of hydrophobicity (%).

(8) Use Application of Amino Resin Crosslinked Particles The amino resin crosslinked particles according to this embodiment can be suitably used for various applications by having the above-described characteristics.

(A) Light diffusing agent The amino resin crosslinked particles according to the present embodiment have a hygroscopicity suppressed, an amino resin composition, a high refractive index of the shell layer, a core-shell structure, and a particle size. Because of its sharp distribution, it has excellent light diffusing characteristics, and because the surface is made of a specific amino resin, it has excellent dispersibility and affinity for binder resins. It can be suitably used for a light diffusing agent for a light diffusing film, a light diffusing agent for an optical resin such as a light diffusing agent for an antiglare film, or a light diffusing agent used for a cover for LED lighting. In the application, the amino resin crosslinked particles preferably have an average particle diameter D of 0.1 to 50 μm, more preferably 0.2 μm or more, more preferably 0.5 μm or more, and particularly preferably 1 μm or more. Moreover, 10 micrometers or less are preferable and especially 5 micrometers or less are preferable.

(B) Anti-blocking agent, lubricant The amino resin cross-linked particles according to the present embodiment are characterized in that the hygroscopicity is suppressed, in addition to the amino resin composition, the particle size distribution is sharp and the heat resistance is excellent. , PET (polyethylene terephthalate) film, PEN (polyethylene naphthalate) film, PP (polypropylene) film, PE (polyethylene) film, and other various polymer films such as anti-blocking agents and lubricants. In this application, the amino resin crosslinked particles preferably have an average particle size of submicron, particularly 0.1 to 0.9 μm, and a particle size variation coefficient (CV value) of 10% or less.

(C) LCD spacer, gap distance retaining agent The amino resin crosslinked particles according to this embodiment have a hygroscopicity suppressed, an amino resin composition, a sharp particle size distribution, and a hydrophobic surface. Therefore, light leakage due to abnormal alignment of liquid crystal molecules can be suppressed, and it can be suitably used for a spacer for LCD. In this application, the amino resin crosslinked particles preferably have an average particle diameter D of 0.5 to 10 μm and a coefficient of variation (CV value) of the particle diameter of 10% or less. Further, the amino resin crosslinked particles according to the present embodiment are not limited to the LCD spacer, but are also suitably used as a gap distance holding agent in bonding and bonding between various electronic components.

(D) Base particles for conductive particles The amino resin crosslinked particles according to this embodiment have a hygroscopicity suppressed, an amino resin composition, a sharp particle size distribution, and a particle surface. Since it consists of a specific amino resin, it can be suitably used for base particles for conductive particles, particularly for conductive particles for anisotropic conductive films, because of its excellent adhesion to a metal plating layer. In this application, the amino resin crosslinked particles preferably have an average particle diameter D of 0.5 to 10 μm and a coefficient of variation (CV value) of the particle diameter of 10% or less.

(E) Matting agent The amino resin cross-linked particles according to the present embodiment have light absorption because the hygroscopicity is suppressed and the amino resin composition has a high refractive index of the shell layer and a core-shell structure. It can be suitably used as a matting agent because of its excellent characteristics, sharp particle size distribution, and easy control of light scattering characteristics. In the application, the amino resin crosslinked particles preferably have an average particle diameter of 0.5 to 10 μm, particularly 1 to 5 μm.

  However, the use application of the amino resin crosslinked particles according to the present embodiment is not limited to the applications exemplified above as long as the characteristics (characteristics) of the amino resin crosslinked particles can be effectively exhibited. It can be used in a wide range of technical fields.

<Resin composition using amino resin crosslinked particles>
(1) Paint resin composition The paint resin composition according to the present invention comprises a binder resin, a solvent, and amino resin crosslinked particles provided by the present invention. Among the above (a) to (e) described in the section “(8) Use of amino resin crosslinked particles” of the amino resin crosslinked particles of the present invention, for (a), (b), and (e), It is preferable to use it in the form of the resin composition for paints described above.

  Here, the binder resin may be appropriately selected from conventionally known binder resins for resin compositions for paints depending on the intended use, and an appropriate amount may be used. Specifically, examples of the binder resin include vinyl resins such as (meth) acrylic resins, (meth) acrylic-styrene resins, and styrene resins; epoxy resins; phenol resins; amino resins; A fluororesin; a silicone resin or the like can be suitably employed.

  As the solvent, conventionally known organic solvents such as ketones, esters, hydrocarbons, ethers, alcohols, glycol derivatives and the like, conventionally known solvents such as mineral oil, water and the like can be used. An appropriate amount may be used by appropriately selecting according to the intended use of the product.

  At this time, the amino resin crosslinked particles obtained by the production method of the present invention may be used by appropriately selecting a desired average particle size between submicron size and micron size according to the intended use.

Preferred Composition of Paint Resin Composition The content of the amino resin crosslinked particles is preferably 1 to 50% by weight, more preferably 10 to 30% by weight, based on 100% by weight of the total amount of the paint resin composition.

  The total amount of the particles and the binder resin is preferably 5 to 70% by mass and more preferably 10 to 50% by mass with respect to 100% by mass of the resin composition for paint.

  The content of the solvent is preferably 30 to 95% by mass and more preferably 50 to 90% by mass with respect to 100% by mass of the resin composition for paint.

(2) Molded resin composition The molded resin composition according to the present invention comprises a binder resin and amino resin crosslinked particles provided by the present invention. Among the above (a) to (e) described in the section “(8) Use of amino resin crosslinked particles” of the amino resin crosslinked particles, (a), (b), and (e) are formed as described above. It is preferably used in the form of a body resin composition.

  Here, as the binder resin, an appropriate amount may be used by appropriately selecting from conventionally known binder resins for molded resin compositions according to the intended use. Specifically, examples of the binder resin include polyolefin resins; polycycloolefin resins; polyester resins; polyimide resins; polyurethane resins; (meth) acrylic resins, styrene resins, (meth) acrylic resins. A vinyl polymer resin such as a styrene resin; a silicone resin; a polycarbonate resin; a thermoplastic or thermosetting resin such as an epoxy resin can be suitably employed.

  At this time, the amino resin cross-linked particles provided by the present invention may be used in an appropriate amount by appropriately selecting a desired average particle size from submicron size to micron size according to the intended use.

Preferred Composition of Resin Composition for Molded Body The content of the amino resin crosslinked particles is preferably 0.005 to 50 mass% with respect to 100 mass% of the total composition. More preferably, it is 0.01-30 mass%.

  The content of the binder resin is preferably 50 to 99.995% by mass and more preferably 70 to 99.99% by mass with respect to 100% by mass of the total composition.

  In the resin composition for paints and the resin composition for molded bodies, if necessary, a conventionally known curing component such as a resin binder curing agent, a crosslinking agent, a curing catalyst, and a curing accelerator may be appropriately selected and used. Good.

[Evaluation methods]
(1) Average particle size (core, grown particles)
A scanning electron microscope image (SEM photograph) was taken so that the total number of particles was about 200, and the diameter of 100 particles randomly selected from the photograph was measured with a caliper, and the number was repeated five times. The average value was defined as the average particle size. Since the particles are substantially spherical, the maximum length of the particles (cross section) of the photographed photograph was measured and used as the diameter.

(2) Thickness of shell layer In the following examples, the thickness t (μm) of the shell layer was determined as follows.

  It calculated | required by the following formula from the average particle diameter D (micrometer) of the growth particle | grains after shell formation, and the average particle diameter d (micrometer) of a core.

Shell layer thickness t (μm) = (D−d) / 2
D and d were randomly selected from a scanning electron microscope image, 100 diameters were measured, and a number average value was obtained to obtain an average particle diameter.

(3) CV value (%)
The value obtained by the following formula from the standard deviation value of the particle diameter measuring method in (1) above was defined as the coefficient of variation CV value (%).

Coefficient of variation CV value (%) = (standard deviation of particle diameter / average particle diameter) × 100
(4) Moisture content (%)
1 g of the pulverized powder was quantified by the Karl Fischer method. The percentage of the water content obtained was defined as the water content (%).

(5) Saturated moisture absorption (%)
After the pulverized powder was left in an atmosphere of a temperature of 30 ° C. and a humidity of 90% RH for 1 day, the same moisture measurement as in (4) above was performed. The percentage of the obtained water content was defined as the saturated moisture absorption (%).

(6) Degree of hydrophobicity (%)
50 cc of water was put into a 200 cc glass beaker, and 0.2 g of the hydrophobized powder (pulverized powder) was floated on the beaker and gently stirred with a stirrer. A burette charged with methyl alcohol in the water is gradually mixed with the methyl alcohol, and the amount of hydrophobicity (using the following formula) is calculated from the amount of methyl alcohol added when the completely floating powder sinks ( %).

(7) Film evaluation 100 parts of polyester polyol, 20 parts of polyfunctional isocyanate (manufactured by Sumika Bayer Urethane Co., Ltd .: Sumidur N320), and 12 parts of particles are uniformly mixed, and then the coating liquid is 100 μm thick by roll coating. The surface was coated so that the dry film thickness was 10 μm. This was left to dry at room temperature for 1 hour and then dried at 80 ° C. for 24 hours to obtain a light diffusion film. The film was allowed to stand in a constant temperature and humidity machine at 40 ° C. in a 90 RH% environment for 1 week, and then evaluated as follows.

Luminance The obtained film was placed on the upper surface of a light guide plate type backlight device, and the luminance was measured using a TOPCON luminance meter BM-7.

-Haze Haze was measured using Nippon Denshoku Industries NDH-1001DP.

● Haze decay rate The haze decay rate (%) was determined using the following formula. In addition, the value of this haze attenuation factor is so preferable that it is small.

[Example 1: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell), guanamine compound (X): BG, melamine compound (Y): example of Me]
(Core (amino resin particle) production)
A 4-necked 500 cc separable flask equipped with a stirrer, a reflux condenser, and a thermometer was charged with 100 parts of melamine (hereinafter also referred to as Me), 193.0 parts of 37% by mass formalin, 3.5% by mass of ammonia water 3.5%. The temperature was raised to 70 ° C. while stirring and held at 70 ° C. for 30 minutes. By this operation, 296.5 parts of amino resin precursor containing liquid (1) was obtained.

  Separately, a 10 L separable flask equipped with a stirrer, a reflux condenser, and a thermometer has a solid concentration of 65 mass% sodium dodecylbenzenesulfonate (manufactured by Kao Corporation: Neoperex G65: hereinafter also referred to as 65 mass% DBSNa). A uniform surfactant aqueous solution heated to 90 ° C. while stirring 6.2 parts and 1400 parts of pure water was prepared.

  296.5 parts of the amino resin precursor-containing liquid (1) is added to the above aqueous surfactant solution under stirring at 90 ° C., held at 90 ° C. for 5 minutes, and then 10 mass% dodecylbenzenesulfonic acid ( Hereinafter, also referred to as DBS.) 50 parts of an aqueous solution was added (solid content concentration: 10.0% by mass). Holding in this state at 90 ° C. for 5 hours, 1752.7 parts of a liquid containing amino resin particles (1) 10.0% by mass (hereinafter, also simply referred to as melamine resin seed liquid (1)) (as solid content) 175 parts). When the obtained particles (amino resin particles (1)) were observed with an SEM, the average particle size was 0.20 μm (CV value: 12%).

(Shell layer formation)
100 parts of benzoguanamine (hereinafter also referred to as BG), 130 parts of 37% by weight formalin, 6.2 parts of 65% by weight DBSNa, 5.0 parts of DBS, and 350 parts of pure water were uniformly dispersed and mixed to obtain a BG dispersion. The BG dispersion was dropped into 1752.7 parts of the melamine resin seed liquid (1) maintained at 90 ° C. over 2 hours with a roller pump (solid content concentration: 14% by mass). After dropping, the mixture is further maintained at 90 ° C. for 5 hours, and then cooled to 30 ° C. to contain 14.0% by mass of amino resin crosslinked particles (1) whose core surface is coated with a condensate of BG and formaldehyde 2343.9 parts of dispersion (1) (hereinafter also simply referred to as BG-coated slurry) was obtained. When the obtained particles (amino resin crosslinked particles (1)) were observed with an SEM, the average particle size was 0.24 μm (CV value: 8.2%).

(Filtering, drying, grinding process)
The BG-coated slurry was subjected to solid-liquid separation with a centrifuge (centrifugal force: 10,000 G), the supernatant was discarded, and only the precipitated cake was taken out into a pad. The filtered cake was put into a 180 ° C. circulating hot air dryer, held for 5 hours, taken out, and then the dried powder was crushed and classified by jet mill classification with a pulverization pressure of 0.7 mPa · s to obtain an amino resin. A crosslinked particle powder (P1) was obtained.

  The obtained powder (P1) had a moisture content of 1.1 mass% and a saturated moisture absorption (left at 30 ° C. and 90% RH for 1 day) of 5.6%. The degree of hydrophobicity was 15%. Various physical properties of the amino resin particles (1) and the crosslinked amino resin particles (1) are shown in Table 1A, and the evaluation results of the amino resin crosslinked particle powder (P1) are shown in Table 2A. The average particle size and CV value of the amino resin crosslinked particle powder (P1) were the same as the measured values (growth particle size and CV value shown in Table 1A) of the amino resin crosslinked particle (1) after the reaction. .

[Example 2: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100% by mass (shell), guanamine compound (X): example of coating up]
In the formation of the shell layer, instead of the BG dispersion of Example 1, 200 parts of BG, 260 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water are uniformly dispersed and mixed. A dispersion (2) containing 16.3% by mass of amino resin crosslinked particles (2) was obtained by performing core preparation and shell formation in the same manner as in Example 1 except that the liquid was dropped. Various physical properties of the resulting amino resin particles (2) and amino resin crosslinked particles (2) are shown in Table 1A. Further, amino resin crosslinked particle powder (P2) was obtained from dispersion (2) in the same manner as in Example 1. The evaluation results of the obtained powder (P2) are shown in Table 2A. The average particle diameter and CV value of the amino resin crosslinked particle powder (P2) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (2) after the reaction. .

[Example 3: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100% by mass (shell), guanamine compound (X): example of coating up]
In the shell layer formation, instead of the BG dispersion of Example 1, 400 parts of BG, 520 parts of 37% by weight formalin, 24.8 parts of 65% by weight DBSNa, 20 parts of DBS, and 1400 parts of pure water are uniformly dispersed and mixed. Except that the liquid was dropped, a core was prepared and a shell was formed in the same manner as in Example 1 to obtain a dispersion (3) containing 19% by mass of amino resin crosslinked particles (3). Various physical properties of the resulting amino resin particles (3) and amino resin crosslinked particles (3) are shown in Table 1A. Further, amino resin crosslinked particle powder (P3) was obtained from dispersion (3) in the same manner as in Example 1. The evaluation results of the obtained powder (P3) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P3) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (3) after the reaction. .

[Example 4: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 80% by mass (shell), guanamine compound (X): coating up, guanamine compound (X): melamine compound ( Y) = 8: 2 Example of mixed coating]
In the shell layer formation, instead of the BG dispersion of Example 1, 160 parts of BG, 40 parts of Me, 285 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water were uniformly dispersed and mixed. A dispersion (4) containing 16.5% by mass of amino resin crosslinked particles (4) was obtained by performing core preparation and shell formation in the same manner as in Example 1 except that the resulting dispersion was dropped. Various physical properties of the resulting amino resin particles (4) and amino resin crosslinked particles (4) are shown in Table 1A. Further, amino resin crosslinked particle powder (P4) was obtained from dispersion (4) in the same manner as in Example 1. The evaluation results of the obtained powder (P4) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P4) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (4) after the reaction. .

[Example 5: Example of guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell), small particle size]
(Preparation of core (amino resin particles))
Using an apparatus equivalent to Example 1, 20 parts of Me, 38.6 parts of 37% by mass formalin, 0.7 part of 25% by mass ammonia water were charged, the temperature was raised to 70 ° C. with stirring, and 30 minutes at 70 ° C. Retained. By this operation, 59.3 parts of amino resin precursor-containing liquid (5) was obtained.

  Separately, in a 2 L separable flask equipped with an apparatus equivalent to that in Example 1, 1.2 parts of 65% by weight DBSNa and 1400 parts of pure water were stirred and a uniform aqueous surfactant solution heated to 90 ° C. was dissolved. It was.

  59.3 parts of the amino resin precursor-containing liquid (5) was added to the surfactant aqueous solution under the above stirring state, and held at 90 ° C. for 5 minutes, and then 10 parts by weight of 10% by weight DBS aqueous solution was added ( Solid content concentration: 2.5% by mass). This state was maintained at 90 ° C. for 5 hours to obtain 1470.5 parts of a dispersion containing 2.4% by mass of amino resin particles (5) (hereinafter also simply referred to as melamine resin seed solution (5)). . When the obtained core (amino resin particles (5)) was observed with an SEM, the average particle size was 0.10 μm (CV value: 12%).

(Shell layer formation)
BG dispersion was prepared by uniformly dispersing and mixing 40 parts of BG, 52 parts of 37% by weight formalin, 2.5 parts of 65% by weight DBSNa, 2.0 parts of DBS and 140 parts of pure water. The dispersion was dropped into 1470.5 parts of melamine resin seed solution (5) over 3 hours. The subsequent steps were synthesized by the same operation as in Example 1 to obtain 1707 parts of dispersion (5) containing 5.4% by mass of amino resin crosslinked particles (5). When the obtained particles (amino resin crosslinked particles (5) were observed by SEM, the average particle size was 0.14 μm (CV value: 9.3%).

  Amino resin crosslinked particle powder (P5) was obtained from dispersion (5) in the same manner as in Example 1. The evaluation results for the obtained powder (P5) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P5) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (5) after the reaction. .

[Example 6: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 66.7 mass% Example of autoclave curing]
In the same manner as in Example 2, core preparation and shell layer formation were performed to obtain amino resin crosslinked particle (6) dispersion (6). The dispersion (6) was charged into a 5 L autoclave, held at 170 ° C. (0.75 mPa) for 5 hours with stirring, and then cooled to 40 ° C. to disperse the amino resin crosslinked particles (6H). A liquid (6H) was obtained. Various physical properties of the core (amino resin particle (6)) and amino resin crosslinked particle (6H) are shown in Table 1A. The amino resin crosslinked particles (6) before heat treatment had an average particle size of 0.29 μm and a CV value of 6.3%.

  After the dispersion (6H) is solid-liquid separated with a centrifuge (centrifugal force: 10,000 G), the supernatant is discarded, 1500 g of the sediment cake is taken out into a beaker, diluted to about 3 L with MeOH, and uniformly dispersed. The mixture was stirred, heated to 50 ° C., held for 2 hours, and further solid-liquid separated with a centrifuge. After this operation was repeated three times, drying and pulverization classification were performed in the same manner as in Example 1 to obtain amino resin crosslinked particle powder (P6). The evaluation results of the obtained powder (P6) are shown in Table 2A. The average particle diameter and CV value of the amino resin crosslinked particle powder (P6) are measured values of the amino resin crosslinked particles (6H) in the dispersion (6H) after the autoclave treatment (growth particle diameters shown in Table 1A, CV value).

  In this example, the particles (amino resin crosslinked particles (6)) in the dispersion (6) after the shell layer formation were also confirmed for the various physical properties shown in Table 1A. As a result, the dispersion after the autoclave treatment was confirmed. It was the same as the value of the particles in (6H) (amino resin crosslinked particles (6H)).

[Example 7: guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 50 mass% (shell), guanamine compound (X): melamine compound (Y) = 50: 50 mixed coating Example]
In forming the shell layer, instead of the BG dispersion of Example 1, 100 parts of cyclohexyne carboguanamine (hereinafter also referred to as CHG), 100 parts of Me, 323 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS 16.8 masses of amino resin crosslinked particles (7) are obtained by carrying out core preparation and shell formation in the same manner as in Example 1 except that 700 parts of pure water is uniformly dispersed and mixed and added dropwise. % Dispersion (7) was obtained. Various physical properties of the resulting amino resin particles (7) and amino resin crosslinked particles (7) are shown in Table 1A. Furthermore, amino resin crosslinked particle powder (P7) was obtained from dispersion (7) in the same manner as in Example 1. The evaluation results for the obtained powder (P7) are shown in Table 2A. The average particle size and CV value of the amino resin crosslinked particle powder (P7) were the same as the measured values (growth particle size and CV value shown in Table 1A) of the amino resin crosslinked particle (7) after the reaction. .

[Example 8: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 12% by mass (shell), guanamine compound (X): melamine compound (Y) = 12: 88 Example]
In forming the shell layer, instead of the BG dispersion of Example 1, 24 parts of CHG, Me188 parts, 371 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water were uniformly dispersed and mixed. Except that the resulting dispersion was added dropwise, core preparation and shell formation were carried out in the same manner as in Example 1 to obtain dispersion (8) containing 17.1% by mass of amino resin crosslinked particles (8). Various physical properties of the resulting amino resin particles (8) and amino resin crosslinked particles (8) are shown in Table 1A. Furthermore, amino resin crosslinked particle powder (P8) was obtained from dispersion (8) in the same manner as in Example 1. The evaluation results for the obtained powder (P8) are shown in Table 2A. The average particle diameter and CV value of the amino resin crosslinked particle powder (P8) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particles (8) after the reaction. .

[Example 9: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100% by mass (shell), guanamine compound (X): examples of coating component acetoguanamine, coating up]
In forming the shell layer, 200 parts of acetoguanamine (hereinafter also referred to as AG), 260 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, 700 parts of pure water instead of the BG dispersion of Example 1 A dispersion containing 16.3% by mass of amino resin crosslinked particles (9) is obtained by carrying out core preparation and shell formation in the same manner as in Example 1 except that a dispersion obtained by uniformly dispersing and mixing is added. 9) was obtained. Various physical properties of the resulting amino resin particles (9) and amino resin crosslinked particles (9) are shown in Table 1A. Further, amino resin crosslinked particle powder (P9) was obtained from dispersion (9) in the same manner as in Example 1. The evaluation results for the obtained powder (P9) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P9) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (9) after the reaction. .

[Example 10: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell), guanamine compound (X): Example of coating component spiro ring-containing guanamine, coating up]
In forming the shell layer, instead of the BG dispersion of Example 1, spiro ring-containing guanamine (Fuji Kasei Kogyo: Delamine CTU-100, hereinafter also referred to as CTUG) 200 parts, 37% by weight formalin 260 parts, 65% by weight Amino resin crosslinked particles (by forming a core and forming a shell in the same manner as in Example 1 except that a dispersion obtained by uniformly dispersing and mixing 12.4 parts of DBSNa, 10 parts of DBS, and 700 parts of pure water was dropped. A dispersion (10) containing 16.3% by mass of 10) was obtained. Various physical properties of the amino resin particles (10) and amino resin crosslinked particles (10) obtained are shown in Table 1A. Furthermore, amino resin crosslinked particle powder (P10) was obtained from dispersion (10) in the same manner as in Example 1. The evaluation results of the obtained powder (P10) are shown in Table 2A. The average particle diameter and CV value of the amino resin crosslinked particle powder (P10) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (10) after the reaction. .

[Example 11: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell), guanamine compound (X): Example of coating component cyclohexenecarboguanamine, coating up]
In the shell layer formation, instead of the BG dispersion of Example 1, dispersion obtained by uniformly dispersing and mixing 200 parts of CHG, 260 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water. A dispersion (11) containing 16.3% by mass of amino resin crosslinked particles (11) was obtained by carrying out core preparation and shell formation in the same manner as in Example 1 except that the liquid was dropped. Various physical properties of the resulting amino resin particles (11) and amino resin crosslinked particles (11) are shown in Table 1A. Further, amino resin crosslinked particle powder (P11) was obtained from dispersion (11) in the same manner as in Example 1. The evaluation results for the obtained powder (P11) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P11) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (11) after the reaction. .

[Example 12: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100% by mass (shell), guanamine compound (X): example of coating up]
In the shell layer formation, instead of the BG dispersion of Example 1, BG 900 parts, 37% by weight formalin 1170 parts, 65% by weight DBSNa 55.8 parts, DBS 45 parts, and pure water 3150 parts are uniformly dispersed and mixed. A dispersion (12) containing 21.8% by mass of amino resin crosslinked particles (12) was obtained by carrying out core preparation and shell formation in the same manner as in Example 1 except that the liquid was dropped over 5 hours. Various physical properties of the resulting amino resin particles (12) and amino resin crosslinked particles (12) are shown in Table 1A. Further, amino resin crosslinked particle powder (P12) was obtained from the dispersion (12) in the same manner as in Example 1. The evaluation results of the obtained powder (P12) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P12) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (12) after the reaction. .

[Example 13: guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell), guanamine compound (X): example of large particle size]
(Preparation of core (amino resin particles))
In the same apparatus and the same operation as in Example 1, 296.5 parts of amino resin precursor-containing liquid (13) was obtained.

  Separately, in a separable flask equipped with the same apparatus as in Example 1, while stirring 3.0 parts of 65% by weight DBSNa and 1400 parts of pure water, a uniform surfactant aqueous solution that was raised to 60 ° C. was dissolved. It was.

  296.5 parts of the amino resin precursor-containing liquid (13) was added to the surfactant aqueous solution under stirring as described above and held at 60 ° C. for 5 minutes, and then 30 parts of a 10% by weight DBS aqueous solution was added (solids). Min 10.0%).

  After introducing DBS, the temperature was raised to 90 ° C., and this state was maintained at 90 ° C. for 5 hours, and a dispersion containing 10.0% by mass of amino resin particles (13) (hereinafter simply referred to as melamine resin seed). Liquid (also referred to as liquid (13)) was obtained. When the obtained core (amino resin particles (13)) was observed with an SEM, the average particle diameter was 0.65 μm.

(Shell layer formation)
In forming the shell layer, synthesis was performed in the same manner as in Example 1 to obtain a dispersion (13) containing 14.0% by mass of amino resin crosslinked particles (13). Various physical properties of the resulting amino resin particles (13) and amino resin crosslinked particles (13) are shown in Table 1A. Further, amino resin crosslinked particle powder (P13) was obtained from dispersion (13) in the same manner as in Example 1. The evaluation results for the obtained powder (P13) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P13) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particle (13) after the reaction. .

[Example 14: guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 80% by mass (shell) and 20% by mass (core), guanamine compound (X): melamine compound (Y) = 8: 2 mixed coating, example of large particle size]
(Preparation of core (amino resin particles))
Using an apparatus equivalent to that in Example 1, 80 parts of Me, 20 parts of BG, 180.4 parts of 37% by mass formalin, 3.5 parts of 25% by mass ammonia water were charged, and the temperature was raised to 70 ° C. while stirring. For 30 minutes. By this operation, 283.9 parts of amino resin precursor containing liquid (14) was obtained.

  Separately, a homogeneous surfactant aqueous solution heated to 90 ° C. was dissolved in a separable flask equipped with the same apparatus as in Example 1 while stirring 6.2 parts of 65% by weight DBSNa and 1800 parts of pure water. It was.

  283.9 parts of the amino resin precursor-containing liquid (14) was added to the surfactant aqueous solution under stirring as described above and held at 90 ° C. for 5 minutes, and then 50 parts of a 10 mass% DBS aqueous solution was added (solid state). Min 8.0%).

  This state was maintained at 90 ° C. for 5 hours to obtain 2140.1 parts of a dispersion containing 8.0% by mass of amino resin particles (14) (hereinafter also simply referred to as melamine resin seed solution (14)). . When the obtained core (amino resin particles (14)) was observed with an SEM, the average particle diameter was 0.42 μm.

(Shell layer formation)
Shell as in Example 1 except that a dispersion obtained by uniformly dispersing and mixing 80 parts of BG, 20 parts of Me, 143 parts of 37% by weight formalin, 6.2 parts of 65% by weight DBSNa, 5 parts of DBS, and 350 parts of pure water was dropped. By performing the formation, a dispersion liquid (14) containing 11.9% by mass of amino resin crosslinked particles (14) was obtained. Various physical properties of the resulting amino resin particles (14) and amino resin crosslinked particles (14) are shown in Table 1A. Further, an amino resin crosslinked particle powder (P14) was obtained from the dispersion (14) in the same manner as in Example 1. The evaluation results for the obtained (P14) are shown in Table 2A. In addition, the average particle diameter and CV value of the amino resin crosslinked particle powder (P14) were the same as the measured values (growth particle diameter and CV value shown in Table 1A) of the amino resin crosslinked particles (14) after the reaction. .

[Example 15: Example of guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% (shell) and 60 mass% (core), coverage ratio Down, large particle diameter]
(Preparation of core (amino resin particles))
Using an apparatus equivalent to that in Example 1, 40 parts of Me, 60 parts of BG, 155.2 parts of 37% by mass formalin, 3.5 parts of 25% by mass ammonia water were charged, and the temperature was raised to 70 ° C. while stirring. Held for 45 minutes. By this operation, 258.7 parts of an amino resin precursor-containing liquid (15) was obtained.

  Separately, a uniform surfactant aqueous solution heated to 70 ° C. was dissolved in a separable flask equipped with the same apparatus as in Example 1 while stirring 10.0 parts of 65% by weight DBSNa and 1340 parts of pure water. It was.

  283.9 parts of the amino resin precursor-containing liquid (15) was added to the surfactant aqueous solution under the above stirring condition and held at 70 ° C. for 5 minutes, and then 30 parts of 10% by weight DBS aqueous solution was added (solid Min 10.0%).

  This state was maintained at 90 ° C. for 5 hours to obtain 1638.7 parts of a dispersion containing 10.0% by mass of amino resin particles (15) (hereinafter also simply referred to as melamine resin seed solution (15)). . When the obtained core (amino resin particles (15)) was observed with an SEM, the average particle size was 3.02 μm.

(Shell layer formation)
Shell formation was carried out in the same manner as in Example 1 except that a dispersion obtained by uniformly dispersing and mixing 50 parts of BG, 65 parts of 37% formalin, 3.1 parts of 65 mass% DBSNa, 2.5 parts of DBS, and 175 parts of pure water was dropped. By carrying out, the dispersion liquid (15) containing 12.1 mass% of amino resin crosslinked particles (15) was obtained. Various physical properties of the resulting amino resin particles (15) and amino resin crosslinked particles (15) are shown in Table 1A. Further, amino resin crosslinked particle powder (P15) was obtained from dispersion (15) in the same manner as in Example 1. The evaluation results of the obtained powder (P15) are shown in Table 2A. The average particle size and CV value of the amino resin crosslinked particle powder (P15) were the same as the measured values (growth particle size and CV value shown in Table 1A) of the amino resin crosslinked particles (15) after the reaction. .

[Comparative Example 1: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 0 mass% Example without coating]
After producing a liquid (melamine resin seed) containing amino resin particles (c1) by the same operation as in Example 1, it was filtered and dried in the same manner as in Example 1 except that no schol layer was formed with BG. Then, pulverization classification was performed to obtain amino resin particle powder (Pc1). Table 1B shows the physical properties of the amino resin particles (c1), and Table 2B shows the evaluation results of the powder (Pc1).

[Comparative Example 2: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 0 mass% Example of melamine compound (Y) coating]
In the shell layer formation, instead of the BG dispersion of Example 1, a dispersion obtained by uniformly dispersing and mixing 200 parts of Me, 386 parts of 37% by weight formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water. A dispersion (c2) containing 17.2% by mass of amino resin crosslinked particles (c2) was obtained by performing core preparation and shell formation in the same manner as in Example 1 except that the liquid was added dropwise. Various physical properties of the resulting amino resin particles (1) and amino resin crosslinked particles (c2) are shown in Table 1B. Further, amino resin crosslinked particle powder (Pc2) was obtained from dispersion (c2) in the same manner as in Example 1. The evaluation results for the obtained powder (Pc2) are shown in Table 2B.

[Comparative Example 3: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 2 mass% (shell), an example in which the guanamine content is small]
In forming the shell layer, instead of the BG dispersion of Example 1, 12 parts of CHG, Me188 parts, 378 parts of 37% formalin, 12.4 parts of 65% by weight DBSNa, 10 parts of DBS, and 700 parts of pure water were uniformly dispersed and mixed. A dispersion (c3) containing 17.2% by mass of amino resin crosslinked particles (c3) was obtained by performing core preparation and shell formation in the same manner as in Example 1 except that the resulting dispersion was dropped. Various physical properties of the resulting amino resin particles (c3) and amino resin crosslinked particles (c3) are shown in Table 1B. Further, amino resin crosslinked particle powder (Pc3) was obtained from dispersion (c3) in the same manner as in Example 1. The evaluation results of the obtained powder (Pc3) are shown in Table 2B.

[Comparative Example 4: Guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100% by mass (core), guanamine compound (X) initial resin condensation, example without coating]
Using an apparatus equivalent to that of Example 1, 100 parts of BG, 130.0 parts of 37% by mass formalin, and 3.4 parts of 25% by mass ammonia water were charged, the temperature was raised to 75 ° C. with stirring, and the mixture was heated at 75 ° C. for 30 minutes. Retained. What was obtained by this operation was made into the amino resin precursor containing liquid (c4).

  Separately, in a 2 L separable flask equipped with the same apparatus as in Example 1, 6.2 parts of 65% by weight DBSNa and 1400 parts of pure water were stirred and a uniform aqueous surfactant solution heated to 90 ° C. was dissolved. It was.

  The amino resin precursor-containing liquid (c4) was added to the surfactant aqueous solution under the above-mentioned stirring state, held at 90 ° C. for 5 minutes, and then 50 parts of 10% by weight DBS aqueous solution was added (solid content concentration: (9.0 mass%), and then kept at 90 ° C. for 5 hours to obtain a dispersion liquid (c4) containing amino resin particles (c4).

  Thereafter, filtration, drying, and pulverization classification were performed in the same manner as in Example 1 except that no schol layer was formed with BG to obtain amino resin particle powder (Pc4). Table 1B shows the physical properties of the amino resin particles (c4), and Table 2B shows the evaluation results of the powder (Pc4).

  Note) “X / (X + Y) total%” in the table and “guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) value (%)” described next to the example number ”are The value (mass%) of the guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) of the whole particle | grains which match | combined the core and shell layer of the particle | grains (growth particle) after shell layer formation.

  “X / (X + Y) core%” in the table is a value (mass%) of the guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) only of the core of the growing particle.

  “X / (X + Y) shell%” in the table is the value (mass%) of the guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) of only the shell layer of the grown particles.

  The core particle diameter means an average particle diameter (μm) of particles (amino resin particles) obtained by core production.

  The growth particle size refers to the average particle size (μm) of particles (amino resin crosslinked particles) after the shell layer is formed.

  The shell layer refers to the thickness (average value) (μm) of the shell layer of the grown particles.

  The shell layer ratio (%) means the thickness (average value) t (μm) of the shell layer / average particle diameter d (μm) of the core × 100 (%).

  However, when autoclaving as in Example 6, each value is shown based on the evaluation results for the particles after autoclaving.

[Discussion]
In the shell layer, the amino resin crosslinked particle powder obtained in Examples 1 to 15 in which the ratio of the guanamine compound (X) to the amino compound used was 10 to 100% was compared with the ratio of 0 to 2%. It was proved that the saturated moisture absorption amount was lower than in Examples 2 and 3.

  In addition, referring to Examples 1 to 3 and Example 12, the ratio of the guanamine compound (X) in the whole particle including the core and the shell layer (“X / (X + Y) total%” described in Table 1A) As the value increases (50 → 90%), the growth particle size increases proportionally (0.24 → 0.43 μm, Table 1A), while the saturated moisture absorption decreases (5.6 → 2.8). %, Table 2A). Moreover, the haze attenuation rate of the film using the particles was also reduced (29 → 14%, Table 2A).

  Further, in Comparative Example 3 in which the ratio of the guanamine compound (X) in the whole particle including the core and the shell layer is 4% (the ratio of the guanamine compound in the shell layer is 6%), Examples 4, 7, and 8 It can be seen that the saturated moisture absorption amount is increased as compared with.

  Further, in Comparative Example 4 corresponding to the production method of the prior art in which particles of guanamine compound (X) / (guanamine compound (X) + melamine compound (Y)) = 100 mass% are obtained by a one-step method, only particles having a large particle size distribution are used. It turns out that it was not obtained (CV value of Table 1B = 32%).

Claims (8)

Amino-resin crosslinked particles having a core-shell structure in which a shell layer is provided on the outer periphery of the core and made of a condensate of an amino compound and formaldehyde, and having a coefficient of variation CV of particle diameter of 30% or less,
The amino resin crosslinked particles, wherein the shell layer is composed of a condensate of an amino compound (B) and formaldehyde, and the ratio of the guanamine compound (X) in the amino compound (B) of the shell layer is 10 to 100% by mass.   The amino resin crosslinked particles according to claim 1, wherein the core is composed of a condensate of an amino compound (A) and formaldehyde, and the ratio of the melamine compound (Y) in the amino compound (A) is 1 to 100% by mass. ;   The amino resin crosslinked particles according to claim 1 or 2, wherein a ratio of the melamine compound (Y) in the amino compound (B) of the shell layer is 0 to 90% by mass.   The amino resin crosslinked particles according to claim 1, wherein the shell layer has a thickness of 0.01 μm or more.   The amino resin according to any one of claims 1 to 4, wherein a thickness (μm) of the shell layer / a diameter (μm) of the core (all are average values) is in a range of 0.1 to 1.5. Cross-linked particles. While dispersing amino resin particles composed of a condensate of amino compound (A) containing 1 to 100% by mass of melamine compound (Y) and formaldehyde in an aqueous medium, the temperature of the aqueous medium is maintained at 50 ° C. or higher. A method for producing crosslinked amino resin particles, wherein a shell layer comprising an amino compound (B) -formaldehyde condensate is formed on the surface of the amino resin particles by adding and mixing the amino compound (B),
The said amino compound (B) contains 10-100 mass% guanamine compound (X), The manufacturing method of amino resin crosslinked particle characterized by the above-mentioned. The production method according to claim 6, wherein the total addition time t (unit: time) of the amino compound (B) satisfies the relationship of the following formula (1).

In the formula, Wx: mass of added amino compound (B) (kg)
Wy: Mass of amino resin particles (kg)   The method according to claim 6 or 7, wherein a curing catalyst is added in the same manner as the amino compound (B).