JP4436054B2 - Amino resin crosslinked pulverized particles and method for producing amino resin crosslinked pulverized particles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to amino resin crosslinked pulverized particles and a method for producing amino resin crosslinked pulverized particles. More specifically, the step of further finely pulverizing the amino resin crosslinked particles obtained by evaporating and drying the water contained in the emulsion while curing the amino resin precursor emulsion under a specific temperature condition. The present invention relates to an amino resin crosslinked pulverized particle and an amino resin crushed crosslinked particle manufacturing method. The amino resin cross-linked pulverized particles are not spherical but are irregularly pulverized. More specifically, particles in which the amino resin crosslinked particles are crushed into irregular shapes by pulverization are mixed. Due to the characteristics of this particle shape, the amino resin crushed crosslinked particle of the present invention is a spherical amino resin crosslinked particle obtained by curing and formalin crosslinking a conventional spherical amino resin precursor emulsion in an emulsion state. With different characteristics. Therefore, matting agents, compounding agents for thermoplastic resins such as polyolefin and polyvinyl chloride, coating agents such as PET film, PP film, PE film and cellophane film, light diffusing agent, light scattering agent, various rubbers, various paints In addition, it can be used for various applications such as a filler such as a toner, a rheology control agent, a colorant, and the like.
[0002]
[Prior art]
Amino resin cross-linked particles make use of their excellent physical properties, matting agents, light diffusing agents, coating agents for various films, fillers for polyolefins, polyvinyl chloride, various rubbers, various paints, toners, etc., as well as rheology. It is used in a wide range of applications such as control agents and colorants. Since the amino resin crosslinked particles are obtained by substantially curing an emulsion of amino resin precursor in an emulsion state (crosslinking between amino compound and formalin), the amino resin crosslinked particles have a spherical shape. . Usually, the crosslinked particles are produced by a filtration step, a dried suspension, and a pulverization step. And it is used for the said use etc. mainly from a viewpoint of slipperiness, smoothness, and a filling property as spherical particle | grains which are bridge | crosslinked and have sufficient particle | grain intensity | strength and particle | grain hardness. In the first place, in the process of curing an emulsion containing a known amino resin precursor, it is performed for the purpose of giving sufficient particle strength and particle hardness to the crosslinked particles. The cross-linked particles are not crushed to such an extent that the obtained particle groups become single particles.
[0003]
In particular, in recent years, application in advanced technology fields and precision technology fields such as application of amino resin crosslinked particles to light diffusion sheets for LCDs has attracted attention, and high-quality amino resin crosslinked particles having no defects are strongly demanded in these fields. It has been.
[0004]
However, in the production method of amino resin crosslinked particles obtained by a conventional production method (for example, see Patent Document 1 and Patent Document 2), the emulsion of the amino resin precursor in a state before the amino resin particles are formed. The purpose of the heating / curing process in the liquid is to cause crosslinking between the formalin and the functional group (specifically, methylol group) of the amino resin, and finally have good hardness, strength and heat resistance. The purpose was to produce the amino resin crosslinked particles. Therefore, the known curing conditions are that the emulsion of the amino resin precursor is cured at a relatively low temperature of 40 to 80 ° C. in the presence of an acid catalyst that is a curing agent, and then the temperature is gradually increased to crosslink within the particles. Is set to be uniform. Moreover, the hardening was a hardening process heated in the state of a liquid, specifically, an emulsion or a suspension. And the grinding | pulverization process normally performed after hardening is performed for the objective of making the state which the amino resin crosslinked particles aggregated in the hardening process and the drying process into the monodispersed state of amino resin crosslinked particles.
[0005]
That is, the cured amino resin crosslinked particles obtained in the above-mentioned known patent documents are crosslinked particles that are highly tough and difficult to break even in the pulverization step after curing because the crosslinked particles are uniformly crosslinked. . That is, the cured amino resin crosslinked particles obtained in the above-mentioned patent document may include particles having a partially pulverized shape even after a subsequent pulverization step, but are substantially spherical or spherical aggregates. I was in physical condition.
[0006]
In addition, since the amino resin crosslinked particles in the above-mentioned patent document have good physical properties (strength, hardness, heat resistance, etc.) that have no practical problems, they are used as crosslinked particles suitable for ordinary applications described above. ing.
[0007]
[Patent Document 1]
JP 49-57091 A
[Patent Document 2]
JP 50-45852 A
[0008]
[Problems to be solved by the invention]
However, when there is a difference in physical properties due to a difference in particle shape even with the same filler, such as fused silica and crystalline silica in the filler, they are properly used depending on the application in which the physical properties due to the difference in particle shape are reflected. Even in the case of amino resin crosslinked particles, there is an increasing need for other physical properties brought about by different shapes in addition to the physical properties brought about by shapes which are usually substantially spherical or aggregates of spherical particles.
[0009]
For example, when the amorphous amino resin crosslinked pulverized particles of the present invention are added to a film as an anti-blocking agent, or added to a resin or synthetic leather as a matting agent, the conventional average particle size of the same level is used. Compared with the spherical particles, the effect of reducing the dropout rate of the particles can be obtained. This is considered to be due to the large contact area between the particles and the film or resin of the base material as compared with the spherical case because it is indefinite. It is also possible to obtain particles having specific physical properties other than the slipperiness and light scattering properties exhibited by ordinary spherical amino resin crosslinked particles.
[0010]
However, the amino resin crosslinked particles obtained through a normal curing process have sufficiently high hardness, strength and toughness since uniform crosslinking occurs as described above, and can be pulverized under normal conditions. Have difficulty. Therefore, it was found that it was difficult to obtain amino resin crosslinked particles having different desired shapes under known production conditions.
[0011]
Therefore, the problem to be solved by the present invention is a method for producing amino resin crosslinked pulverized particles having an irregular shape, not a substantially spherical or spherical aggregate, and an amino resin crosslinked pulverized product produced by the production method. To provide particles.
[0012]
[Means for Solving the Problems]
The present inventor has intensively studied to solve the above-mentioned problems, and further studied on conditions for curing and drying an emulsion of an amino resin precursor formed from an amino-based compound and holymarin. As a result, the condition is such that the emulsion of the amino resin precursor to which the acid catalyst is added is not cured in a liquid state but is also dried together with the water of the emulsion at a relatively high temperature. By adopting a process in which the curing (crosslinking) of the amino compound and formalin and the drying of the produced crosslinked particles occur in parallel, and after curing, pulverization, preferably jet pulverization is performed. Thus, it was succeeded in obtaining amino resin-crosslinked pulverized particles that were pulverized into an irregular shape instead of a substantially spherical or spherical aggregate. By adopting a process in which the curing (crosslinking) of the amino compound and formalin takes place in parallel with the drying of the crosslinked particles, the amino compound is non-uniformly crosslinked, resulting in a crushed crosslinked state. It was possible.
[0013]
Moreover, it is also possible to obtain amino resin cross-linked pulverized particles having relatively high hardness by further heat-treating the pulverized particles as necessary.
[0014]
The configuration of the present invention is as follows.
[0015]
(1) A catalyst is added to an emulsion containing emulsified particles of an amino resin precursor obtained by emulsifying an amino resin precursor obtained by reacting an amino compound with formaldehyde, and the emulsion To obtain a dried amino resin crosslinked particle through a step of evaporating water from the emulsion while curing the emulsified particles of the amino resin precursor to form an amino resin crosslinked particle, and the amino resin crosslinked obtained after drying A method for producing crosslinked amino resin particles, wherein the particles are further pulverized.
[0016]
(2) A method for producing crosslinked amino resin particles, wherein the temperature of heating the emulsion is 70 ° C. or higher.
[0017]
(3) In the step of evaporating water from the emulsion, the temperature of the emulsion is raised to 70 ° C. or higher within 1 hour after the addition of the catalyst, and the emulsion particles in the emulsion are cured while the emulsion particles are cured. A method for producing crosslinked amino resin particles characterized by evaporating water from an emulsion.
[0018]
(4) The emulsion is heated in the range of 70 ° C. to 150 ° C. to evaporate water from the emulsion while curing the emulsion particles of the amino resin precursor to form amino resin crosslinked particles. The amino resin cross-linked particles are produced by the method described above, wherein the water content of the amino resin cross-linked particles is 5% or less.
[0019]
(5) Amino resin cross-linked pulverized particles obtained by the above production method, wherein the amino resin cross-linked pulverized particles have a non-spherical shape rather than a spherical shape.
[0020]
(6) A catalyst is added to an emulsion containing emulsified particles of an amino resin precursor obtained by emulsifying an amino resin precursor obtained by reacting an amino compound with formaldehyde, and the emulsion In the amino resin cross-linked pulverized particles obtained by pulverizing amino resin particles produced by the step of curing the amino resin precursor emulsified particles to form amino resin cross-linked particles,
The average particle diameter (A) of the emulsified particles of the amino resin precursor before curing the emulsified particles of the amino resin precursor is in the range of 0.5 to 500 μm,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by curing and pulverizing the emulsified particles of the amino resin precursor is in the range of 0.35 to 350 μm,
Furthermore, the amino resin crosslinked pulverized particles, wherein the ratio of the pulverization degree represented by the average particle diameter (B) / the average particle diameter (A) is 0.7 or less.
[0021]
(7) The average particle diameter (A) of the emulsified particles of the amino resin precursor before curing the emulsified particles of the amino resin precursor is in the range of 0.5 to 500 μm, the variation coefficient is 60% or less,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by curing and pulverizing the emulsified particles of the amino resin precursor is in the range of 0.35 to 350 μm, the coefficient of variation is 60% or less,
Furthermore, the above-mentioned amino resin crosslinked pulverized particles, wherein the ratio of the pulverization degree represented by the average particle diameter (B) / the average particle diameter (A) is 0.7 or less.
[0022]
More specifically, the amino resin crosslinked pulverized particles are characterized in that the shape of the amino resin crosslinked pulverized particles is not substantially spherical but irregular.
[0023]
More specifically, the amino resin crosslinked pulverized particles in which the amino compound contains at least one compound selected from the group consisting of benzoguanamine, cyclohexanecarboguanamine, cyclohexenecarboguanamine, and melamine in an amount of 40% by weight or more. It is a manufacturing method.
[0024]
Moreover, this invention is the amino resin bridge | crosslinking grinding | pulverization particle | grains obtained by said manufacturing method. More specifically, the amino resin cross-linked pulverized particles are characterized in that the shape of the amino resin cross-linked pulverized particles is not substantially spherical but irregular.
[0025]
Further, the present invention may be a dispersion containing the above-mentioned amino resin cross-linked pulverized particles, and can be used as a film additive or a resin additive. Therefore, this invention is also an additive for films containing the said amino resin crosslinked ground particle. It is also a resin additive containing the above-mentioned amino resin crosslinked pulverized particles.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the amino resin crosslinked pulverized particles and the method for producing amino resin crosslinked pulverized particles according to the present invention will be described in more detail. However, the scope of the present invention is not limited to these explanations, and other than the following examples, It can implement suitably in the range which does not impair the meaning of this invention.
[0027]
In the present specification, the particle state in the production process of the amino resin crosslinked particles produced in the former stage of the amino resin crosslinked pulverized particles in the present invention is divided into two liquids, “emulsion” and “suspension”. Express with state. According to the usual definition, “emulsion” refers to a liquid in which liquid particles are dispersed as colloidal particles or coarser particles, forming a milky state. The solid particles are dispersed as colloidal particles or particles that can be seen with a microscope.
[0028]
Therefore, in the process of producing amino resin crosslinked particles, which is the pre-stage production process of amino resin crosslinked crushed particles in the present invention, the state during emulsification should be expressed as an emulsion and the state after curing as a suspension. There is. Moreover, both forms may coexist during curing, but in this specification, the state during curing may be expressed as a suspension.
[0029]
The process for producing crosslinked amino resin particles according to the present invention includes a step of adding a catalyst to an emulsion containing an amino resin precursor and curing and drying it while evaporating water in a specific temperature range as a previous step. This is a production method for obtaining amino resin crosslinked particles. Through the above curing and drying process, amino resin crosslinked particles are formed in the emulsion containing the amino resin precursor to which the catalyst has been added, and at the same time, the moisture is evaporated and the drying proceeds and the amino can be pulverized. Resin crosslinked particles can be produced. For convenience, the process of curing and drying may be referred to as a preceding process, and the pulverizing process for pulverizing the amino resin crosslinked particles may be referred to as a subsequent process. In the method for producing crosslinked amino resin particles including a step of curing and drying under specific conditions, a catalyst is applied to an emulsion obtained by emulsifying an amino resin precursor obtained by reacting an amino compound with formaldehyde. It is a method for producing amino resin crosslinked particles by curing and drying the amino resin precursor by adding, and it is a preferred embodiment that the curing and drying temperature is in the range of 70 to 150 ° C. . More preferably, it is the range of 80 degreeC-120 degreeC.
[0030]
A production process for obtaining an amino resin precursor as an initial condensation reaction product by reacting an amino compound with formaldehyde may be referred to as a resinification process. In reacting an amino compound with formaldehyde, water is usually used as a solvent. Therefore, as a reaction form, an amino compound is added to react with formaldehyde in the form of an aqueous solution (formalin), or trioxane or paraformaldehyde is added to water so that formaldehyde can be generated in water. Preferred examples include a method in which an amino compound is added to the aqueous solution to cause the reaction, and the former method is more preferable from the viewpoint of economy, such as the necessity of an adjustment tank for the aqueous formaldehyde solution and the availability. .
[0031]
The reaction form of the amino compound and formaldehyde may be any form in which the amino compound and formaldehyde react in a mixed state. For example, in addition to the form in which the amino compound is added to an aqueous formaldehyde solution, amino The form which adds the aqueous solution of formaldehyde to a system compound may be sufficient.
[0032]
In general, the resinification step for carrying out the above reaction is preferably carried out under stirring by a generally known stirring device or the like.
[0033]
An amino compound that can be used as a raw material in the resinification step is not particularly limited, and examples thereof include benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, and cyclohexenecarboguanamine. And melamine. Of these, amino compounds having a triazine ring are generally more preferred, but benzoguanamine is excellent in dyeability in the initial condensation state because it has a benzene ring and two reactive groups, and is acceptable after crosslinking. It is particularly preferable because of its excellent flexibility (hardness), stain resistance, heat resistance, solvent resistance and chemical resistance. These amino compounds may be used alone or in combination of two or more.
[0034]
The total of the amino compounds exemplified above (benzoguanamine, cyclohexanecarboguanamine, cyclohexenecarboguanamine and melamine) is preferably 40% by weight or more, more preferably 60% by weight or more, in the whole amino compounds to be used. More preferably, it is 80% by weight or more, and most preferably 100% by weight. When the total of the amino compounds exemplified above is 40% by weight or more, an effect that amino resin crosslinked particles having excellent heat resistance and solvent resistance can be obtained can be obtained.
[0035]
The molar ratio (amino compound (mol) / formaldehyde (mol)) of the amino compound and formaldehyde to be reacted in the resinification step is preferably 1 / 3.5 to 1 / 1.5, and 1/3 5 to 1 / 1.8 is more preferable, and 1 / 3.2 to 1/2 is more preferable. If the molar ratio is less than 1 / 3.5, the unreacted formaldehyde may increase. If it exceeds 1 / 1.5, the unreacted amino compound may increase.
[0036]
When water is used as a solvent, the amount of amino compound and formaldehyde added to water, that is, the concentration of the amino compound and formaldehyde at the time of preparation should be higher as long as the reaction is not hindered. Is desirable. More specifically, the viscosity in the temperature range of 95 to 98 ° C. of the reaction solution containing the amino resin precursor as a reactant is 2 × 10 ^-2 ~ 5.5 × 10 ^-2 The concentration can be adjusted and controlled within the range of Pa · s (20 to 55 cP), and more preferably, the concentration of the amino resin precursor in the emulsion is 30 to 30 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 in the range of 60% by weight.
[0037]
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 95 to 98 ° C. is 2 × 10 ^-2 ~ 5.5 × 10 ^-2 Pa · s (20 to 55 cP) is preferable, and 2.5 × 10 8 is more preferable. ^-2 ~ 5.5 × 10 ^-2 Pa · s (25 to 55 cP), more preferably 3.0 × 10 ^-2 ~ 5.5 × 10 ^-2 Pa · s (30 to 55 cP).
[0038]
The viscosity measurement method is optimally a method using a viscometer so that the progress of the reaction can be grasped immediately (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. This viscometer has a vibrating part that constantly vibrates. When the vibrating part is immersed in the reaction liquid, the viscosity of the reaction liquid increases and a load is applied to the vibrating part. Is converted to and displayed immediately. Moreover, even if not instantaneous, it is possible to sample the reaction solution and determine the end point of the reaction based on the viscosity of the reaction solution. More preferably, the vibration viscometer as described above is used.
[0039]
By reacting an amino compound with formaldehyde in water, an amino resin precursor which is a so-called initial condensate can be obtained. The reaction temperature is preferably within a temperature range of 95 to 98 ° C. so that the progress of the reaction can be immediately grasped and the end point of the reaction can be accurately determined. The reaction between the amino compound and formaldehyde has a viscosity of 2 × 10 ^-2 ~ 5.5 × 10 ^-2 What is necessary is just to complete | finish by operation, such as cooling this reaction liquid, when it becomes in the range of Pa * s. Thereby, the reaction liquid containing an amino resin precursor is obtained. The reaction time is not particularly limited.
[0040]
About the amino resin precursor obtained in the resinification step, the molar ratio of the structural unit derived from the amino compound and the structural unit derived from formaldehyde constituting the amino resin precursor (the structural unit derived from the amino compound (mol)) / Formaldehyde-derived structural unit (mole)) is preferably 1 / 3.5 to 1 / 1.5, more preferably 1 / 3.5 to 1 / 1.8, and 1/3 More preferably, it is 2 to 1/2. By setting the molar ratio within the above range, particles having a narrow particle size distribution can be obtained.
[0041]
Normally, the viscosity of the reaction solution at the end of the reaction is significantly higher than the viscosity of the aqueous solution charged with the amino compound and formaldehyde (at the start of the reaction). Not affected. 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.
[0042]
In the method for producing amino resin cross-linked particles of the present invention, the amino resin cross-linked particles finally obtained can be obtained by lowering the viscosity of the reaction liquid in the resinification step of obtaining the reaction liquid containing the amino resin precursor. The particle diameter can be reduced. However, the viscosity of the reaction solution is 2 × 10 ^-2 If it is less than Pa · s, or 5.5 × 10 ^-2 When it exceeds Pa · s, it is impossible to obtain amino resin crosslinked particles having a particle diameter almost uniform (narrow particle size distribution) in the end. That is, the viscosity of the reaction solution is 2 × 10 ^-2 If it is less than Pa · s (20 cP), the stability of the emulsion obtained in the emulsification step described below becomes poor. For this reason, when the amino resin precursor is cured in the curing step, the resulting amino resin crosslinked particles may be enlarged or the particles may be aggregated, and the particle diameter of the amino resin crosslinked particles is controlled. This may result in amino resin crosslinked particles having a wide particle size distribution.
In addition, when the stability of the emulsion is poor, the particle diameter (average particle diameter) of the amino resin crosslinked particles changes every time of production (for each batch), which may cause variations in the product. . On the other hand, the viscosity of the reaction solution is 5.5 × 10 ^-2 If Pa · s (55 cP) is exceeded, the load applied to the high-speed stirrer used in the emulsification step described later is too large and the shearing force decreases, so that the reaction solution can be sufficiently stirred (emulsified). There is a risk that it will not be possible. For this reason, it becomes impossible to control the particle diameter of the finally obtained amino resin crosslinked particles, which may result in amino resin crosslinked particles having 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 amino resin crosslinked particles as a pre-stage of the production method for obtaining the amino resin crosslinked pulverized particles of the present invention. Moreover, in the manufacturing method of the amino resin crosslinked ground particle of this invention, the form which adjusts the brittleness and hardness of an amino resin crosslinked particle is preferable so that it can grind | pulverize in a subsequent grinding | pulverization process on specific hardening conditions.
[0043]
Changes in the particle diameter (average particle diameter) of the amino resin crosslinked particles explained above, and the particle diameter of the amino resin crosslinked particles finally obtained by deviating from the preferable range of the viscosity of the reaction liquid can be controlled. Even if it is eliminated, it is within the scope of the embodiment of the present invention as long as the obtained amino resin crosslinked particles can be pulverized. In other words, in some cases, depending on the conditions of the production process in the previous stage, even if amino resin crosslinked particles having a slightly wide particle size distribution are obtained, they may be finally pulverized to obtain amino resin crosslinked particles having a desired effect. is there.
[0044]
In the emulsification step, the amino resin precursor obtained in the resinification step is emulsified to obtain an emulsion of the amino resin precursor. In emulsifying, for example, it is preferable to use an emulsifier capable of constituting a protective colloid.
[0045]
Examples of the emulsifier include polyvinyl alcohol, carboxymethyl cellulose, sodium alginate, polyacrylic acid, water-soluble polyacrylate, and polyvinyl pyrrolidone. These emulsifiers may be used in the form of an aqueous solution in which the entire amount is dissolved in water, or a part of the emulsifier is used in the form of an aqueous solution, and the rest is used as it is (for example, powder, granule, liquid, etc.). You may do it. Among the emulsifiers exemplified above, 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 larger the amount of emulsifier used for the amino resin precursor obtained in the resinification step, the smaller the particle size of the particles produced. 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.
[0046]
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 weight. 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 weight, the productivity of the amino resin crosslinked particles may be reduced, and if it exceeds 60% by weight, the resulting amino resin crosslinked particles may be enlarged or particles may be May agglomerate, and the particle diameter of the amino resin crosslinked particles cannot be controlled, so that amino resin crosslinked particles having a wide particle size distribution may be obtained.
[0047]
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), specifically, for example, a so-called high-speed stirrer, homomixer, TK homomixer (special Kikaka Kogyo Co., Ltd.), 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), etc. The method is preferred.
[0048]
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 crosslinked particle | grains may be obtained. Specifically, emulsification is performed so that the average particle diameter of the emulsified amino resin precursor is 0.5 to 500 μm by appropriately considering the type of container and stirring blade, the stirring speed, the stirring time, the emulsification temperature, and the like. . Furthermore, it is preferable to emulsify so that it may become 1-300 micrometers. Furthermore, it is preferable to emulsify so that it may become 1-200 micrometers, Furthermore, it is preferable to emulsify so that it may become 1-100 micrometers. Furthermore, it is preferable to emulsify so that it may become 1-50 micrometers, More preferably, it is 2-30 micrometers, More preferably, it is 2-20 micrometers. By emulsifying the amino resin precursor so as to be in the above particle size range, it is possible to finally obtain amino resin crosslinked pulverized particles having a desired particle size range, which will be described later, even after a subsequent pulverization step.
[0049]
The average particle size of the above-mentioned emulsified amino resin precursor (the average particle size of the amino resin precursor dispersed in the emulsion obtained by emulsification) is the Coulter Multisizer II type described in the examples below. Measured value.
[0050]
In this invention, the process of adding and diluting water to the emulsion obtained through the said emulsification process may be included. In this case, the average particle size of the emulsified amino resin precursor (amino resin precursor dispersed in the emulsion obtained by emulsification) is shown as a form indicating the state of the emulsion before dilution obtained through the emulsification step. Average particle diameter). In the case where the emulsion obtained through the emulsification step includes a step of adding water to dilute, the average particle size of the amino resin precursor measured using Coulter Multisizer type II is 0.5. Emulsification is carried out to a thickness of ˜500 μm. Furthermore, it is preferable to add water when it becomes 1-300 micrometers. More preferably, it is when it becomes 1-200 micrometers. Furthermore, it is a more preferable form to add water and dilute when it becomes 1 to 100 μm, and it is a more preferable form to add water and dilute when it becomes 1 to 50 μm, more preferably 2 It is preferable to dilute by adding water when it becomes ˜30 μm, more preferably 2 to 20 μm.
[0051]
Also obtained by final pulverization based on the average particle diameter of the amino resin precursor dispersed in the emulsion obtained by emulsification obtained by measurement using Coulter Multisizer type II. It is a preferred embodiment to define the state of the obtained crosslinked amino resin particles of the present invention.
[0052]
Specifically, as described above, an emulsion containing amino resin precursor emulsion particles having a certain average particle size range and having a catalyst added thereto is heated to cure the emulsion emulsion particles of amino resin precursor. The amino resin cross-linked product of the present invention is obtained by a process of obtaining a dried amino resin cross-linked particle through a step of evaporating water from the emulsion while using the amino resin cross-linked particle, and further crushing the amino resin cross-linked particle obtained after drying. Although the pulverized particles are produced, in a preferred embodiment of the present invention, the average particle diameter (A) of the emulsified particles of the amino resin precursor before curing the emulsified particles of the amino resin precursor is 0.5 to In the range of 500 μm,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by curing and pulverizing the emulsified particles of the amino resin precursor is in the range of 0.35 to 350 μm,
Furthermore, amino resin crosslinked pulverized particles having a pulverization degree ratio represented by the average particle diameter (B) / the average particle diameter (A) of 0.7 or less can be obtained.
[0053]
Adjusting the production conditions so that the pulverization degree is 0.7 or less is a preferred embodiment for producing the crosslinked amino resin particles according to the present invention. More preferably, it is 0.6 or less. When the ratio of the degree of pulverization is about 0.9, it is difficult to obtain the effect of the present case because the pulverized amino resin crosslinked pulverized particles are not obtained.
[0054]
The average particle diameter (A) of the emulsion particles of the amino resin precursor before curing the emulsion particles of the amino resin precursor is in the range of 0.5 to 500 μm, and the standard deviation of the average particle diameter is the average particle diameter. The coefficient of variation expressed in (%) after dividing by is 60% or less,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by curing and pulverizing the emulsified particles of the amino resin precursor is in the range of 0.35 to 350 μm, the coefficient of variation is 60% or less,
Furthermore, the ratio of the pulverization degree represented by the average particle diameter (B) / the average particle diameter (A) is 0.7 or less, which is the average particle diameter of the amino resin crosslinked pulverized particles according to the present invention. This is a preferred embodiment because the distribution is narrower.
[0055]
Specifically, the variation coefficient is a value (%) expressed by a variation coefficient = standard deviation of the average particle diameter of the emulsified particles / average particle diameter measured with a multisizer. A smaller value of the coefficient of variation means that the particle size distribution of the particles becomes narrower. When the distribution of the average particle diameter of the amino resin crosslinked pulverized particles is narrower, the light scattering characteristics of the amino resin crosslinked pulverized particles are more uniform when used as a light scattering agent. Moreover, fluidity is further improved when used as a resin additive or resin compounding agent.
[0056]
Moreover, the more preferable range of the said average particle diameter (B) of the amino resin bridge | crosslinking grinding | pulverization particle | grains obtained by grind | pulverizing the emulsified particle of the said amino resin precursor after hardening is 0.35-350 micrometers. Furthermore, it is preferable to emulsify so that it may become 0.7-210 micrometers. Furthermore, it is preferable to emulsify so that it may become 0.7-140 micrometers, and also it is preferable to grind | pulverize so that it may become 0.7-70 micrometers. Furthermore, it is preferable to grind | pulverize so that it may become 0.7-35 micrometers, More preferably, it is 1.4-21 micrometers, More preferably, it is 1.4-14 micrometers.
[0057]
In the production method of the present invention, in order to more reliably prevent the finally obtained amino resin crosslinked particles from agglomerating more securely, if necessary, inorganic particles may be added to the emulsion obtained after the emulsification step. Can be added. Specific examples of inorganic particles include silica fine particles, zirconia fine particles, aluminum powder, alumina sol, and serie sol. Among them, silica fine particles are more preferable because they are easily available. The specific surface area of the inorganic particles is preferably 10 to 400 m <2> / g, more preferably 20 to 350 m <2> / g, still more preferably 30 to 300 m <2> / g. The particle diameter of the inorganic particles is more preferably 0.2 μm or less, more preferably 0.1 μm or less, and further preferably 0.05 μm or less. When the specific surface area and the particle diameter are within the above ranges, a further excellent effect can be exhibited in preventing the finally obtained amino resin crosslinked particles from being strongly aggregated.
[0058]
The method of adding the inorganic particles to the emulsion is not particularly limited. Specifically, for example, the method of adding the inorganic particles as they are (particulate), or the inorganic particles are dispersed in water. The method of adding in the state of a dispersion liquid etc. are mentioned. The amount of inorganic particles added to the emulsion is preferably 1 to 30 parts by weight, more preferably 2 to 28 parts by weight, even more preferably 100 parts by weight of the amino resin precursor contained in the emulsion. Is 3 to 25 parts by weight. If it is less than 1 part by weight, it may not be possible to sufficiently prevent the finally obtained amino resin crosslinked particles from agglomerating sufficiently. If it exceeds 30 parts by weight, aggregates of only inorganic particles are generated. There is a risk. Moreover, as a stirring method at the time of adding inorganic particles, the method using the above-described apparatus capable of stirring strongly (apparatus having high shearing force) firmly fixes inorganic particles to amino resin particles. preferable.
[0059]
In the curing step, the emulsion obtained in the emulsification step is diluted by adding water as necessary, and then a catalyst (specifically a curing catalyst) is added to cure the emulsified amino resin precursor. By carrying out (curing the amino resin precursor in a milky state), amino resin crosslinked particles (specifically, suspension of amino resin crosslinked particles) are obtained.
[0060]
As the catalyst (curing catalyst), an acid catalyst is suitable. Acid catalysts 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, benzoic acid, Organic acids such as acetic acid, propionic acid, salicylic acid and the like can be used. Of the acid catalysts exemplified above, a mineral acid is preferable from the viewpoint of curing speed, and sulfuric acid is more preferable from the viewpoints of corrosiveness to equipment, safety when using a mineral acid, and the like. Moreover, when using a sulfuric acid as said catalyst, compared with the case where a dodecylbenzenesulfonic acid is used, for example, the amino resin bridge | crosslinking particle | grains finally obtained are preferable at the point which does not discolor or has high solvent resistance. These may be used alone or in combination of two or more. The amount of the catalyst used is preferably 0.1 to 5 parts by weight, more preferably 0.3 to 100 parts by weight with respect to 100 parts by weight of the amino resin precursor in the emulsion obtained by the emulsification step. 4.5 parts by weight, 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 0 with respect to 1 mol of the amino compound used as the raw material compound. 0.01 to 0.1 mol. When the amount of the catalyst used is less than 0.002 mol relative to 1 mol of the amino compound, the reaction may take a long time or curing may be insufficient.
[0061]
The curing reaction in the curing step performed in the step of obtaining the amino resin pulverized particles of the present invention (the step in which curing and drying are performed) is preferably 70 ° C. or higher under normal pressure or reduced pressure. More preferably, it is 80 ° C. or higher. At this time, the temperature of the emulsion becomes 70 ° C. or higher. More preferably, it is carried out at a temperature in the range of 70 to 150 ° C, more preferably 80 to 120 ° C. When the reaction temperature of the curing reaction (drying temperature at the time of drying) is less than 70 ° C., the curing does not proceed sufficiently, and the solvent resistance and heat resistance of the resulting amino resin crosslinked particles may be reduced, When it exceeds 150 ° C., a heating source is required, which is not economical.
[0062]
The end point of the curing reaction (the step in which curing and drying are performed) may be determined based on the moisture in the amino resin crosslinked particles that are the powder obtained by drying, and the moisture in the dried powder is 5% or less. You just have to end it. Further, the reaction time of the curing reaction (the step in which curing and drying are performed) is not particularly limited.
More preferably, the moisture content of the crosslinked amino resin particles after drying for preferably producing the amino resin crosslinked particles of the present invention is 3% or less. More preferably, it is 2% or less.
[0063]
In the production process of the amino resin crosslinked pulverized particles of the present invention, more preferably, in the step of evaporating water from the emulsion, the emulsion is heated to 70 ° C. or more within 1 hour after the addition of the catalyst. The step of evaporating moisture from the emulsion while curing the emulsified particles in the emulsion is performed.
[0064]
More preferably, the catalyst is added to the emulsion containing the emulsion particles of the amino resin precursor and stirred, and the reaction vessel containing the emulsion is added to another heating device or heating device within 1 hour. The step of raising the temperature of the emulsion to 70 ° C. or higher is performed by heating the heating device to 70 ° C. or higher.
The emulsion containing the emulsified particles of the amino resin precursor as a pre-process for producing the amino resin crosslinked pulverized particles of the present invention undergoes this step, whereby the emulsion is cured while curing the emulsified particles in the emulsion. The water contained in can be evaporated. The heating device used at this time may be any device that can hold the emulsion and can be heated, and specifically uses a container such as a vat and uses a heating dryer, There are forms that use paddle dryers and rotary kilns. In addition, a spray dryer (spray dryer) can be used as the heating device, but in order to adapt the drying method using the spray dryer, in order to prevent the fusion phenomenon of amino resin particles in the spray dryer, It is preferable to carry out in such a form that amino resin particles that have been cured to some extent after addition of the catalyst are introduced into a spray dryer. Therefore, as a simpler method, the particles are cured and dried by using a container such as a bat as a heating device and using a dryer.
[0065]
Therefore, the step of curing and drying, which is an essential step in obtaining the amino resin crushed crosslinked particles of the present invention, is a drying selected from a heat dryer using a bat container, a paddle dryer, a rotary kiln and a spray dryer. A form using a machine is preferred. More preferably, a heat dryer using a bat container is used.
[0066]
More preferably, when the catalyst is added to the emulsion before the curing and drying steps, the emulsion is in a stirred state. The catalyst can be mixed more uniformly and in a short time.
[0067]
By passing through the above manufacturing process, in particular, by adding a catalyst to the emulsion containing the amino resin precursor and drying the moisture while curing, pulverization (specifically, after the crosslinking curing reaction) Can obtain amino resin particles that can be crushed in the jet pulverization step. Probably through the above specific curing step, cross-linking of the amino resin and formalin occurs non-uniformly, and it is possible to produce amino resin cross-linked particles that are hard and brittle and are easily pulverized.
[0068]
In a generally known method for producing amino resin crosslinked particles, a curing agent is blended in an emulsion or an emulsion of amino resin initial condensate (or amino resin precursor) and cured, and amino resin crosslinked particles having good final physical properties are cured. In other words, in order to retain sufficient strength or heat resistance as the amino resin crosslinked particles, a relatively low to medium temperature (50 to 50) in the state of an emulsion or suspension containing the amino resin initial condensate is obtained. 100 ° C.) or after being held at a relatively low temperature (40 to 60 ° C.) for 1 hour and then cured at a normal pressure or under a pressure in a temperature range of 60 to 200 ° C. Therefore, in such a known production condition of the amino resin crosslinked particles, a large amount of moisture is not removed from the system in the curing step.
[0069]
In other words, the known curing conditions for the amino resin crosslinked particles are heat applied in an emulsion state, that is, in an aqueous solution state. The moisture is removed by filtering the amino resin crosslinked particles produced after curing and drying the amino resin. After that, it is pulverized, but the amino resin crosslinked particles produced through the production process of such known amino resin crosslinked particles are such that the agglomerated cured particles are not aggregated and become monodisperse particles even if pulverized. Yes, the particles themselves are hard to break.
[0070]
In other words, when the amino resin particles obtained under known production conditions are pulverized, they are partially crushed particles (ground particles) depending on the curing conditions and the like, but are mixed together, but the state of the amino resin particles obtained is substantially spherical. Is shown. This is clear in an electron micrograph or the like in a comparative example of the present invention described later. The amino resin particles produced under known production conditions have an overwhelmingly large number of spherical particles.
[0071]
In the production process of known amino resin crosslinked particles, it is cured at a relatively low temperature to a medium temperature (50 to 100 ° C.) in the presence of water, or held at a relatively low temperature (40 to 60 ° C.) for 1 hour, and then at atmospheric pressure. Alternatively, since it is crosslinked under conditions of curing in a temperature range of 60 to 200 ° C. under pressure, it is difficult to physically grind because of high toughness, and it is difficult to obtain particles that are crushed and irregularly shaped by grinding. there were.
[0072]
Specifically, the amino resin particles can be obtained by emulsifying a reaction product of an amino compound such as benzoguanamine or melamine and formaldehyde with an emulsifier and then curing with an acid catalyst or the like. Conventionally, in this curing step, in order to make the cross-linking in the particles uniform, a method of gradually heating and curing after being held at a relatively low temperature for several hours has been employed (see JP-A-50-45852). . By adopting such a formulation, toughness was produced in the particles, and spherical particles that were not easily crushed even when an external force was applied were obtained. Known amino resin cross-linked particles include particles that have been partially pulverized to such an extent that the aggregation of particles is crushed even after the pulverization step, but most of the particles that are substantially spherical even after the pulverization step. Thus, it was difficult to obtain amino resin crosslinked pulverized particles that became indeterminate due to the crushing of the amino resin particles that occurred in the pulverization step as in the present invention.
[0073]
However, as described above, the present invention employs temperature conditions and process conditions that cause curing and moisture drying to occur simultaneously.
[0074]
As a result of further intensive studies, it is possible to obtain particles with relatively low toughness by simultaneously curing and drying (removing water) at relatively high temperatures (80 to 150 ° C.). It was found that irregularly shaped particles obtained by crushing the particles were obtained. Thereafter, if necessary, an amorphous amino resin crosslinked particle imparted with moderate toughness can be obtained by advancing the condensation reaction for several hours in an atmosphere of about 130 to 200 ° C.
[0075]
A known pulverizer can be used as the pulverizer used to obtain the pulverized particles of the present invention. A classification function may be attached. As the pulverizer, a bantam mill, a pulverizer (manufactured by Hosokawa Micron Co., Ltd.), a sample mill (manufactured by Fuji Powder Co., Ltd.) and the like can be used. As the pulverizer, LABO JET (manufactured by Nippon Pneumatic Kogyo Co., Ltd., Jet Mill STJ-200 (manufactured by Seishin Enterprise Co., Ltd.), etc. can be used. This is preferable.
[0076]
In addition, an inert gas having an oxygen concentration of 10% or less is used as a gas used for pulverization, classification, and powder conveyance during pulverization or pulverization classification in order to avoid the risk of dust explosion. It is preferable. More preferably, it is 5% or less, More preferably, it is 3% or less. As the inert gas, a rare gas such as nitrogen gas, helium gas, or argon gas can be used. Nitrogen gas is preferable from the viewpoint of economy and availability.
[0077]
Further, regarding the above gas, the moisture content in the gas is 6 g / m. ³ It is preferable to be controlled as follows. More preferably, the water content in the gas is 5 g / m. ³ It is as follows. More preferably 3 g / m ³ It is as follows. More preferably 1 g / m ³ It is as follows. The lower limit of the water content is not limited and is ideally 0, but in reality it is 0.05 g / m. ³ That's it.
[0078]
Further, a classification step can be performed as necessary. Classification methods that can be used in the classification process include an airflow classification method and a sieve classification method. In consideration of continuous productivity and the possibility of clogging the screen, an air classification method is preferable. In the pulverizer or pulverizer and the subsequent classification process, it is preferable to control the oxygen concentration and water content in the gas used or the carrier gas as described above.
[0079]
In the manufacturing method of this invention, the coloring process which adds the aqueous solution formed by melt | dissolving dye in water can be included in an emulsion.
[0080]
The amino resin crosslinked particles obtained by curing the amino resin precursor and its emulsified particles are excellent in affinity with the dye. The dye added to the obtained emulsion in the coloring step is preferably a dye that dissolves in water, that is, a water-soluble dye. Specific examples of water-soluble dyes include basic dyes such as rhodamine B, rhodamine 6GCP (manufactured by Sumitomo Chemical Co., Ltd.), methyl violet FN, and Victoria blue FN; quinoline yellow SS-5G and quinoline yellow. Examples include, but are not particularly limited to, acid dyes such as GC (manufactured by Chuo Synthetic Chemical Co., Ltd.), Acid Magenta O, Methyl Violet FB, Victoria Blue FB; These dyes may be used alone, or. Two or more types may be used in combination.
[0081]
The concentration of the dye in the aqueous solution is not particularly limited, but is more preferably in the range of 0.1 to 5% by weight, and still more preferably in the range of 1 to 3% by weight. If the concentration of the dye is less than 0.1% by weight, the amount of the aqueous solution to be added becomes large, and the productivity of the amino resin crosslinked particles may be lowered. On the other hand, when the concentration of the dye exceeds 5% by weight, the stability of the emulsion is lowered, and thus the resulting amino resin crosslinked particles may be enlarged or the particles may be aggregated. The method for preparing the aqueous solution obtained by dissolving the dye in water and the method for adding and mixing the aqueous solution to the emulsion are not particularly limited.
[0082]
Moreover, in the manufacturing method of this invention, the pre-stage coloring process which adds the dispersion liquid which disperse | distributes dye to water to the reaction liquid obtained at the said resinification process can be included.
[0083]
The dye is preferably a dye that is dispersed in water, that is, an oil-soluble dye. Specific examples of oil-soluble dyes include, for example, Oil Orange B, Oil Blue BA (manufactured by Chuo Synthetic Chemical Co., Ltd.), Azosol Brilliant Yellow 4GF, Azosol Fast Blue GLA, Oil Red TR-71, etc. Solvent-soluble dyes; disperse dyes such as Fast Yellow YL, Fast Blue FG, Seriton Pink FF3B, Seriton Pink 3B; and the like. These dyes may be used alone or in combination of two or more.
[0084]
In addition, a pre-stage coloring step in which a dispersion obtained by dispersing an oil-soluble dye in water is added to the reaction solution obtained in the resinification step, and a coloring in which an aqueous solution obtained by dissolving the dye in water is added to the emulsion. The process may be performed only in one of them, or both processes may be used together, but the combined use is more sufficiently and uniformly colored, that is, the color tone of individual particles This is preferable in that even more uniform amino resin crosslinked particles can be obtained.
[0085]
The content of the dye in the dispersion obtained by dispersing the oil-soluble dye in water is not particularly limited, but is preferably in the range of 1 to 50% by weight, more preferably in the range of 20 to 40% by weight. Okauchi is more preferable. When the content of the dye is less than 1% by weight, the amount of the added dispersion becomes large, and the productivity of the amino resin crosslinked particles may be lowered. On the other hand, when the content of the dye exceeds 50% by weight, the fluidity of the dispersion liquid is lowered, so that the handling property at the time of addition is lowered and the addition may take time. Further, since oil-soluble dyes have poor wettability with water, a dispersion aid can be used as necessary when the dye is dispersed in water. The method for preparing a dispersion obtained by dispersing the dye in water and the method for adding and mixing the dispersion to the reaction solution are not particularly limited.
Yes.
[0086]
The above reaction liquid (solution) after adding a dispersion obtained by dispersing an oil-soluble dye in water, for example, using an alkali agent such as sodium carbonate, sodium hydroxide, potassium hydroxide, or aqueous ammonia, the pH is adjusted. It is preferable to adjust within the range of 6-12, more preferably within the range of 7-9. Thereby, the condensation / curing of the amino resin precursor in the curing step can be sufficiently controlled. The amount of alkali agent used is not particularly limited. Moreover, although the method of adding and mixing an alkaline agent with the reaction liquid in the state of aqueous solution is suitable, this method is not specifically limited.
[0087]
As described above, the amino resin crosslinked particles used for producing the amino resin crosslinked particles of the present invention can be colored, and finally colored amino resin pulverized particles having various shapes can be obtained. Can do. The colored amino resin pulverized particles thus obtained have a shape different from that of the known colored amino resin pulverized particles, and thus can exhibit specific coloring performance.
[0088]
In the manufacturing method of this invention, it is preferable to perform the heating process which heats the amino resin bridge | crosslinking grinding | pulverization particle | grains obtained by grind | pulverizing at the temperature of 130-200 degreeC. By performing the heating step, moisture adhering to the amino resin crosslinked particles and remaining formaldehyde can be removed, and condensation (crosslinking) in the amino resin crosslinked particles can be further promoted. When the heating temperature is lower than 130 ° C., condensation (crosslinking) in the amino resin crosslinked particles cannot be sufficiently promoted, and the hardness, solvent resistance and heat resistance of the amino resin crosslinked particles can be improved. If it exceeds 200 ° C., the resulting amino resin crosslinked particles may be discolored.
[0089]
The heating method in the heating step is not particularly limited, and a generally known heating method may be used.
[0090]
What is necessary is just to complete | finish a heating process, for example in the stage in which the moisture content of amino resin crosslinked particle became 3 weight% or less. Further, the heating time is not particularly limited.
[0091]
In the manufacturing method of this invention, you may further perform processes, such as a grinding | pulverization (crushing) and classification, as needed after the said heating process.
[0092]
The average particle size of the crosslinked amino resin particles obtained by the production method of the present invention is further preferably 0.05 to 30 μm, more preferably 0.1 to 15 μm. If the average particle size is less than 0.05 μm, the matting effect when used as a matting agent for paints may not be sufficient, and if it exceeds 30 μm, it is sufficient when used as a rheology control agent. Performance may not be obtained.
[0093]
For the amino resin constituting the amino resin crosslinked pulverized particles obtained by the production method of the present invention, the molar ratio between the structural unit derived from the amino compound and the structural unit derived from formaldehyde is 1 mol of the structural unit derived from the amino compound. It is preferable that the number of moles of the structural unit derived from formaldehyde is 1.05 to 3 mol, and more preferably 1.1 to 2.5 mol. When the number of moles of the structural unit derived from formaldehyde relative to 1 mole of the structural unit derived from the amino compound is less than 1.05 mole, the degree of crosslinking of the resulting amino resin crosslinked pulverized particles is lowered, and the heat resistance and solvent resistance are reduced. When the amount exceeds 3 moles, the resulting amino resin crosslinked pulverized particles are not sufficiently cured, and the heat resistance and solvent resistance may be lowered.
[0094]
Since the amino resin cross-linked pulverized particles obtained by the production method of the present invention have the performance and physical properties as described above, for example, as in the past, a matting agent, a light diffusing agent, and various film coating agents. It can be used in application fields such as fillers and resin additives for polyolefins, polyvinyl chloride, various rubbers, various paints and toners, or resin additives for films; rheology control agents and colorants. In particular, it is suitable for applications where high-quality amino resin crosslinked pulverized particles having no defects are required.
[0095]
The amino resin cross-linked pulverized particles in the present invention are particles that are clearly pulverized when an electron micrograph is taken and the shape thereof is observed. In this invention, this state may be described as an amorphous amino resin pulverized particle. The shape of the amino resin-crosslinked pulverized particles of the present invention is obtained by subjecting an electron micrograph taken at a magnification of 2000 times to image processing and counting spherical particles (that is, not pulverized) in the electron micrograph region. The feature of the shape can be shown preferably by expressing the distribution.
Specifically, the area (B) of the spherical particles based on the area (A) of the photographed electron micrograph.
The ratio (B) / (A) may be calculated, and the output value (C) may be displayed as a spherical particle area ratio (%). At this time, a method of calculating how small the spherical particle area ratio of the pulverized particles is based on the spherical particle area ratio of particles having the same average particle diameter manufactured under the manufacturing conditions that are difficult to pulverize May be combined.
Further, the number of the particles (Y) may be counted on the assumption that the size of the spherical particles (Y) is X μm or more. In addition, by performing image processing, the area of the particle (Y) may be (By), and the ratio may be expressed by (By) / (A) and displayed (%). Commercially available software can be used for image processing.
More specifically, by using software such as WinROOF manufactured by Mitani Corporation, spherical amino resin is obtained by counting spherical particles (that is, not pulverized) in the electron micrograph region. Particle distribution can be calculated by area. More specifically, circular pattern matching is performed using the software. By performing such processing on the photographed electron micrograph, it is a preferred embodiment to express the shape characteristics of the crosslinked amino resin particles according to the present invention.
[0096]
For example, the amino resin crosslinked particles produced under the known pulverized condition and manufactured through the pulverization process are based on the area (A) of the spherical particles taken on the basis of the area (A) of the photographed electron micrograph. B), the ratio of (B) / (A) is calculated, and the value (C) is expressed as (%) as the spherical particle area ratio. It becomes larger than the spherical particle area ratio (pulverization).
[0097]
On the contrary, the amino resin crosslinked particles produced under the condition of being easily pulverized according to the present invention and produced through the pulverization process are obtained by using the above-mentioned spherical particle, based on the area (A) of the photographed electron micrograph. The area was calculated (B), the ratio was calculated by (B) / (A), and the value (C) was expressed as (%) as the spherical particle area ratio. Smaller than the spherical particle area ratio (known product). Therefore, as a preferred form of the amino resin crosslinked pulverized particles of the present invention, the shape characteristics are shown in the form that the above-mentioned spherical particle area ratio is a specific value or less. One of these embodiments is illustrated in the following figure.
[0098]
Further, the above-mentioned spherical particle area ratio of the obtained pulverized particles can be defined as a certain numerical value calculated on the basis of the spherical particle area ratio manufactured under non-pulverized conditions.
[0099]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.
In addition, the moisture measuring method of the dry powder of amino resin crosslinked particles in the present invention is as follows.
[0100]
The dry powder is put in a mortar and sufficiently pulverized using a pestle. About 2.0 g of the crushed sample is precisely weighed (up to 1 mg) and placed in an aluminum cup (diameter 6 cm, depth 3 cm) (the weight of the aluminum cup itself is also precisely weighed (up to 1 mg). Heat for 30 minutes at a temperature of 120 ° C. After heating, the aluminum cup is allowed to cool in a desiccator for 15 minutes, then its weight is measured and the weight loss of the sample is calculated to obtain moisture.
[0101]
Sample weight: Ag
Aluminum cup weight: Bg
Aluminum cup weight after heating and cooling: Cg
Moisture (%) = 100− (C−B) / A * 100
[Example 1]
In a reaction vessel having a capacity of 10 L equipped with a stirrer, reflux condenser, thermometer, vibration viscometer (manufactured by MIVI ITS Japan, model name: MIVI 6001), benzoguanamine 3000 g (16 mol) as an amino compound, 2600 g of formalin with a concentration of 37 wt% (formaldehyde 32 mol) and 10 g of sodium carbonate 10 wt% aqueous solution (0.01 mol of sodium carbonate) were charged, and the temperature was raised while stirring to react at 95 ° C.
[0102]
And the viscosity of the reaction solution is 4.5 × 10 ^-2 The resinification step was completed by cooling the reaction solution at the time when Pa · s (45 cP) was reached (5 hours after the start of the reaction). Thereby, the reaction liquid containing the amino resin precursor which is the initial condensate of benzoguanamine and formaldehyde was obtained.
[0103]
Next, polyvinyl alcohol (stock) as an emulsifier was added to a 25 L (inner diameter 28 cm) reaction kettle equipped with a reflux condenser, a pipeline homomixer (SL type, manufactured by Tokushu Kika Kogyo Co., Ltd.), a stirrer, a thermometer, etc. An aqueous solution prepared by dissolving 100 g of Kuraray Co., Ltd., trade name: PVA205) in 7500 g of water was charged and heated to 75 ° C. while stirring. Then, after adding the above reaction liquid to the reaction kettle, the liquid temperature is raised to 77 ° C. and maintained at 77 ° C., in order to suppress foaming, a silicone-based antifoaming agent (FS Antifoam 025, Dow A solution made up to 100 g by diluting 0.1 g of Corning Asia Co., Ltd. (active ingredient 28%) with water was added. By vigorously stirring the contents at a rotational speed of 5000 rpm, the amino resin precursor was emulsified to obtain an emulsion having a concentration of 30.8% by weight of the amino resin precursor. When the emulsion was measured with a Coulter Multisizer (manufactured by Coulter, measurement particle number: 30000, using aperture-AP200), the average particle size (d50) of the amino resin precursor in the emulsion was 8.5 μm. The standard deviation was 2.8 μm. (The coefficient of variation indicated by the standard deviation / average particle diameter was 33%.) Thereafter, 2500 g of room temperature pure water was added, and the obtained emulsion was cooled to 30 ° C.
[0104]
The aperture is used to measure the average particle diameter and the distribution of the particles in the emulsion state or the suspended particles in the Coulter Multisizer, depending on the average particle diameter of the particles. Choose an appropriate size. When an aperture having a large number is used, the particle size distribution of particles having a large average particle diameter can be measured more accurately. Therefore, it is preferable to select an appropriate numerical aperture when measuring the average particle diameter.
[0105]
Next, an aqueous solution obtained by dissolving 40 g (0.4 mol) of sulfuric acid as a catalyst in 1200 g of pure water and a solution obtained by diluting 0.2 g of an antifoaming agent with water to suppress foaming to 150 g were added to the milk. After adding to the suspension (the temperature of the content is 30 ° C.) and stirring, the emulsion was put into a stainless steel vat and cured and dried for 8 hours in a constant temperature dryer at 110 ° C. (as a catalyst) 1 hour after the addition of sulfuric acid, the temperature of the emulsion reached 80 ° C). The moisture in the powder after drying was 4.0%. The obtained dry powder was pulverized and classified using a jet pulverization classifier (with a classification function), device name: LABO JET, manufactured by Nippon Pneumatic Industrial Co., Ltd. As operating conditions, powder feed amount: 0.5 kg / hr, pulverizer supply air pressure: 0.4 MPa, secondary air (louver): small, adjust string: 3 sheets (24 mm), distance ring: 10 mm were used. . At this time, the secondary air used in the pulverizing section was air having a moisture content in the air of 3 g / m 3. As a result, white powdery amino resin crosslinked pulverized particles were obtained. The powder was heat-treated at 150 ° C. for 3 hours in a box dryer, and then the amino resin crosslinked pulverized particles were measured with a Coulter Multisizer (manufactured by Coulter, measuring particle number: 30000, using aperture AP50). The average particle size (d50) was 4.4 μm, and the standard deviation was 2.0 μm (the coefficient of variation was 45%). By pulverizing, the average particle size was smaller than the emulsified particles.
[0106]
When the obtained particles were observed with an SEM, they were indeterminate white particles containing many pulverized particles as shown in FIG.
[Comparative Example 1]
After adding the sulfuric acid aqueous solution as the catalyst in Example 1, the same operation as in Example 1 was performed except that the following operation was performed without curing and drying with a constant temperature dryer. The average particle diameter (d50) of the amino resin precursor in the emulsion was 8.4 μm, and the standard deviation was 2.8 μm (AP200 used, variation coefficient was 33%).
[0107]
After the sulfuric acid aqueous solution was added (the temperature of the contents was 30 ° C.), the temperature was raised at 10 ° C./hr until the temperature reached 90 ° C. with stirring. And after reaching 90 degreeC, it hold | maintained at this temperature for 1 hour, and the amino resin precursor was condensed and hardened. Therefore, the reaction time is a total of 7 hours.
[0108]
After finishing the curing step, the suspension containing the amino resin particles was cooled to 30 ° C. Thereafter, the amino resin particles were taken out of the suspension by filtration. The amino resin particles taken out were heat-treated at 150 ° C. for 3 hours (the water content in the amino resin particles after heat drying was 2%), and then pulverized with a jet pulverizer under the same operating conditions as in Example 1. did.
The obtained white powder was measured with a Coulter Multisizer (manufactured by Coulter, measured particle number: 30000), and the average particle size (d50) was 8.7 μm, and the standard deviation was 3.0 μm. (AP200 used, variation coefficient is 34%), and the average particle size and particle size distribution were the same as those of the emulsified particles. Observation of the obtained particles by SEM revealed spherical white particles as shown in FIG.
[0109]
[Example 2]
An emulsion was obtained in the same manner as in Example 1, and then the following operation was performed before adding the sulfuric acid aqueous solution.
[0110]
Subsequently, 3000 g of an aqueous dispersion of Aerogel 200 (manufactured by Nippon Aerosil Co., Ltd.) having a solid content concentration of 10% by weight as an aqueous dispersion of silica, which is an inorganic compound, was added to the reaction kettle, and then the contents were mixed with a homomixer. The product was stirred for 5 minutes at a rotational speed of 4000 rpm. The average particle diameter (d50) of the amino resin precursor in the emulsion was 8.6 μm, and the standard deviation was 2.8 μm (AP200 used, variation coefficient was 33%).
[0111]
Next, an aqueous sulfuric acid solution was added and stirred in the same manner as in Example 1, followed by curing and drying to obtain white amino resin particle powder (water content in the dried powder was 3.0%). The obtained amino resin particles were pulverized using a bantam mill (manufactured by Hosokawa Micron Corporation). Next, the pulverized powder was classified using an airflow classifier (device name: Classiel N-5, manufactured by Seishin Enterprise Co., Ltd.) (as operating conditions, powder feed amount: 1 kg / hr, Rotor rotation speed: 4000 rpm, guide vane: 10 degrees, secondary air opening: 100%, tertiary air opening: 0%, air flow rate: 9.1 m3 / hr, secondary air differential pressure: 0.20 mmAq). The obtained powder was heat-treated at 150 ° C. for 3 hours using a box-type dryer to obtain amino resin crosslinked pulverized particles in the form of white powder. The amino resin cross-linked pulverized particles were measured with a Coulter Multisizer (manufactured by Coulter, measuring particle number: 30000). As a result, the average particle diameter (d50) was 4.6 μm, and the standard deviation was 1.6 μm (AP50 used, variation) The coefficient was 35%). Further, when the shape of the white powder particles was observed with an SEM, it was indefinite. By pulverizing, the average particle size was smaller than the emulsified particles.
[0112]
In order to show the particle shape, an electron micrograph was taken. About the said Example 1 and the comparative example 1, the said grinding | pulverization particle | grains and spherical particle | grains were manufactured on each conditions, the said particle | grain sample was extract | collected from three different places in each lot, and the electron micrograph was image | photographed. 1-4 (taken 15 pictures in each shape) shows an example. All of the electron micrographs showed almost similar shapes. Therefore, the state of the amino resin crosslinked pulverized particles of the present invention and the known spherical amino resin crosslinked particles is characterized by performing image processing as shown in FIG. 5 or FIG. 6 and obtaining the distribution area of the spherical particles. Can do. Specifically, the amino resin crosslinked pulverized particles of the present invention clearly have fewer spherical particles than the spherical particles. Further, the distribution area of the particles may be calculated based on the area of the electron micrograph taken under a predetermined condition.
[0113]
【The invention's effect】
The amino resin crosslinked pulverized particles according to the present invention are not substantially spherical but are irregularly pulverized. The above-mentioned amino resin cross-linked pulverized particles employ a specific curing and drying process in which curing and moisture drying occur in parallel with the curing process of the emulsion containing the amino resin precursor by adding a catalyst. After the particles are manufactured, the amino resin crosslinking can be pulverized. By passing through the above-mentioned specific curing and drying step, amino resin cross-linking between the amino resin and formalin occurs non-uniformly, and it is possible to produce amino resin cross-linked particles that are easily pulverized and in a hard and brittle cross-linked state.
[0114]
Particles obtained by crushing the amino resin crosslinked particles of the present invention into an irregular shape by pulverization are mixed. Due to the characteristics of this particle shape, the amino resin crushed crosslinked particle of the present invention is a spherical amino resin crosslinked particle obtained by curing and formalin crosslinking a conventional spherical amino resin precursor emulsion in an emulsion state. With different characteristics. Therefore, matting agents, compounding agents for thermoplastic resins such as polyolefin and polyvinyl chloride, coating agents such as PET film, PP film, PE film and cellophane film, light diffusing agent, light scattering agent, various rubbers, various paints It can be used for fillers such as toner. Further, an additive for toner for developing an electrostatic latent image may be used. Alternatively, for example, it can be used as a resin additive, a resin additive for a film, a rheology control agent, a colorant and the like, and it can be used as an amino resin crushed crosslinked particle exhibiting specific performances for various uses.
[0115]
Specifically, when the amorphous amino resin crosslinked pulverized particles of the present invention are added to a film as an anti-blocking agent, or added to a resin or synthetic leather as a matting agent, the same average particle size is obtained. Compared to conventional spherical amino resin crosslinked particles having a diameter, an effect of reducing the dropout rate of the particles can be expected. this is,
Since the pulverized particles of the present invention are not in a spherical shape, but in an irregular shape containing a large number of pulverized amino resin crosslinked particles, the particles are in comparison with spherical amino resin crosslinked particles. This is thought to be due to the large contact area between the film and the substrate film. It is also possible to obtain particles having specific physical properties other than the slipperiness and light scattering properties exhibited by ordinary spherical amino resin crosslinked particles. When manufactured as colored particles, there is a possibility that specific reflection may occur. Therefore, colored particles that can cope with various coloring properties can be obtained.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is attached with electronic data obtained by taking an image of an electron micrograph measured at a magnification of 2000 times of pulverized particles obtained in Example 1 of the present invention.
FIG. 2 is attached with electronic data obtained by capturing an electron micrograph image measured at a magnification of 3500 times that of the pulverized particles obtained in Example 1 of the present invention.
FIG. 3 is attached with electronic data obtained by taking an image of an electron micrograph measured at a magnification of 2000 times of the pulverized particles obtained in Comparative Example 1 of the present invention.
FIG. 4 is attached with electronic data obtained by taking an image of an electron micrograph measured at a magnification of 3500 times that of the pulverized particles obtained in Comparative Example 1 of the present invention.
FIG. 5 is an image processing of electronic data (the same data as FIG. 1) obtained by capturing an image of an electron micrograph measured at a magnification of 2000 times that of the pulverized particles obtained in Example 1 of the present invention. 1 shows an example of a method for calculating the area of spherical particles distributed in pulverized particles. The circles in FIG. 5 are the particles determined to be spherical by visual observation. The arrow points to it. This figure shows a state in the middle of image processing, not a form in which all particles are marked.
6 is an image process of electronic data (same data as FIG. 3) obtained by capturing an electron micrograph image measured at a magnification of 2000 times that of the spherical particles obtained in Comparative Example 1 of the present invention. 1 shows an example of a method for calculating the area of spherical particles. The circles in FIG. 6 are the particles determined to be spherical by visual observation. The arrow points to it. This figure shows the middle of image processing, not the form in which all particles are marked.

Claims (6)

  A catalyst is added to an emulsion containing emulsified particles of an amino resin precursor obtained by emulsifying an amino resin precursor obtained by reacting an amino compound with formaldehyde, and the emulsion is heated to 70 ° C. The emulsion is heated in a range of ˜150 ° C. to cure the amino resin precursor emulsified particles to form amino resin crosslinked particles, thereby evaporating water from the emulsion, so that the moisture of the amino resin crosslinked particles after moisture evaporation is 5% or less. The method for producing crosslinked amino resin particles, wherein the crosslinked amino resin particles after evaporation of water are further pulverized.   The manufacturing method of the amino resin bridge | crosslinking grinding | pulverization particle | grains of Claim 1 which adds an antifoamer to the emulsion containing the emulsion particle | grains of the said amino resin precursor.   In the step of evaporating water from the emulsion, the emulsion is heated while the emulsion is heated to 70 ° C. or more within 1 hour after the addition of the catalyst, and the emulsion particles in the emulsion are cured. The method for producing the amino resin crosslinked pulverized particles according to claim 1 or 2, wherein water is evaporated from the water. The amino resin cross-linked pulverized particles obtained by the production method according to any one of claims 1 to 3, wherein the amino resin cross-linked pulverized particles are not substantially spherical but irregular. Amino resin crosslinked pulverized particles. In the amino resin crosslinked pulverized particles obtained by the production method according to any one of claims 1 to 3,
The average particle diameter (A) of the emulsified particles of the amino resin precursor before curing the emulsified particles of the amino resin precursor is in the range of 0.5 to 500 μm,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by pulverizing the emulsified particles of the amino resin precursor after curing is in the range of 0.35 to 350 μm,
Furthermore, the amino resin crosslinked pulverized particles, wherein the ratio of the pulverization degree represented by the average particle diameter (B) / the average particle diameter (A) is 0.7 or less. The average particle diameter (A) of the emulsified particles of the amino resin precursor before curing the emulsified particles of the amino resin precursor is in the range of 0.5 to 500 μm, the variation coefficient is 60% or less,
The average particle diameter (B) of the amino resin crosslinked pulverized particles obtained by curing and pulverizing the emulsified particles of the amino resin precursor is in the range of 0.35 to 350 μm, and the coefficient of variation is 60% or less,
Furthermore, the ratio of the grinding | pulverization degree represented by the said average particle diameter (B) / the said average particle diameter (A) is 0.7 or less, The amino resin bridge | crosslinking grinding | pulverization particle | grains of Claim 5 characterized by the above-mentioned.

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