JP2015009166A - Manufacturing method for particle mixture, optical adhesive composition, and optical adhesive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a particle mixture which keeps organic particles and inorganic particles efficiently dispersed while preventing primary particles from being destroyed.SOLUTION: A manufacturing method, used for manufacturing a particle mixture containing inorganic particles, organic particles, and a dispersion medium by a mill comprising a pulverization chamber, a rotor rotatably provided in the pulverization chamber, and a particulate pulverization medium housed in the pulverization chamber, includes the step of feeding the inorganic particles, the organic particles, and the dispersion medium into the pulverization chamber and the step of rotating the rotor in the state that the inorganic particles, the organic particles, and the dispersion medium are present in the pulverization chamber, with a number average particle size of the pulverization medium at 0.1 mm - 3 mm and the peripheral velocity of the rotor during the rotation of the rotor at 0.2 m/sec - 3.0/sec.

Description

  The present invention relates to a method for producing a particle mixture, an optical pressure-sensitive adhesive composition, and an optical pressure-sensitive adhesive layer.

  When an optical member such as an optical film is bonded, an optical pressure-sensitive adhesive composition may be used to improve adhesive strength. The optical pressure-sensitive adhesive composition generally contains a pressure-sensitive adhesive material such as a polymer and a solvent, and if necessary, contains other components. For example, the optical pressure-sensitive adhesive composition may contain particles for the purpose of imparting light diffusibility to the pressure-sensitive adhesive composition.

  However, particles contained in the adhesive composition are generally small and easily aggregate. Therefore, when producing a pressure-sensitive adhesive composition, it is common to take a method in which the agglomerated particles are broken and then the broken particles are mixed with the pressure-sensitive adhesive material. In order to solve such agglomerated particles, for example, a dispersing device such as a bead mill is often used (Patent Document 1).

JP-A-6-277479

  In recent years, optical adhesive compositions containing a combination of inorganic and organic particles have been developed. Such an adhesive composition is produced, for example, by preparing a particle mixture containing inorganic particles, organic particles, and a dispersion medium, and mixing the particle mixture and the adhesive material. However, as described above, the particles contained in the optical pressure-sensitive adhesive composition are likely to agglomerate due to their small size, and among them, organic particles tend to agglomerate particularly. Therefore, in the production of the pressure-sensitive adhesive composition, in general, a particle mixture is produced by performing a dispersion treatment using a dispersing device such as a bead mill in order to break up the agglomerated particles, and then the particle mixture and the pressure-sensitive material are mixed. .

  However, when a composition containing inorganic particles and organic particles is treated with a bead mill, not only is agglomerated particles (hereinafter sometimes referred to as “secondary particles”) unresolved, but When broken, the primary particle size may change. Therefore, it has heretofore been difficult to obtain an adhesive composition containing organic particles and inorganic particles having a desired particle size distribution.

  In the optical adhesive composition, it is desired to appropriately adjust the particle size distribution of the contained particles from the viewpoint of expressing desired optical properties. For this reason, the destruction of the primary particles by the dispersion treatment for unraveling the secondary particles has hindered the improvement of the optical characteristics.

  The present invention was devised in view of the above-described problems, and a method for producing a particle mixture in which organic particles and inorganic particles can be efficiently dispersed while preventing destruction of primary particles; a particle mixture obtained by the production method And an optical pressure-sensitive adhesive layer produced using the optical pressure-sensitive adhesive composition.

As a result of intensive studies to solve the above-mentioned problems, the present inventor used a mill equipped with a grinding chamber, a rotor and a grinding medium to produce a particle mixture containing inorganic particles, organic particles and a dispersion medium. By keeping the number average particle diameter of the medium and the peripheral speed of the rotor within a predetermined range, it is possible to efficiently disperse the inorganic particles and organic particles while preventing the inorganic particles and organic particles from being destroyed. As a result, the present invention has been completed.
That is, the present invention is as follows.

[1] A particle mixture containing inorganic particles, organic particles, and a dispersion medium using a mill including a grinding chamber, a rotor rotatably provided in the grinding chamber, and a particulate grinding medium housed in the grinding chamber A manufacturing method for manufacturing
Supplying the inorganic particles, the organic particles and the dispersion medium into the grinding chamber;
Rotating the rotor with the inorganic particles, the organic particles and the dispersion medium in the grinding chamber,
The number average particle size of the grinding medium is 0.1 mm to 3 mm,
The method for producing a particle mixture, wherein a circumferential speed of the rotor during rotation of the rotor is 0.2 m / sec to 3.0 m / sec.
[2] The method for producing a particle mixture according to [1], wherein the primary particles of the inorganic particles have a volume average particle diameter of 1 nm to 200 nm.
[3] The method for producing a particle mixture according to [1] or [2], wherein the primary particles of the organic particles have a volume average particle diameter of 0.1 μm to 10 μm.
[4] An optical pressure-sensitive adhesive composition comprising the particle mixture produced by the production method according to any one of [1] to [3] and a pressure-sensitive adhesive material.
[5] An optical pressure-sensitive adhesive layer formed of a material obtained by drying the optical pressure-sensitive adhesive composition according to [4].

  According to the present invention, a particle mixture containing non-aggregated organic particles, non-aggregated inorganic particles and a dispersion medium can be efficiently produced without destroying the primary particles when dispersing the organic particles and the inorganic particles. A method for producing a particle mixture that can be produced; an optical pressure-sensitive adhesive composition containing the particle mixture obtained by the production method; and an optical pressure-sensitive adhesive layer produced using the optical pressure-sensitive adhesive composition can be realized. .

FIG. 1 is a schematic view schematically showing an apparatus for producing a particle mixture according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments. However, the present invention is not limited to the embodiments described below, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalent scope thereof.

  In the following description, the destruction of the particle means that the primary particle diameter is changed by breaking the primary particle of the particle. Therefore, it is not included in the destruction of particles that the aggregated particles are unraveled, that is, the secondary particles are unraveled to become primary particles.

  Moreover, (meth) acrylic acid includes acrylic acid and methacrylic acid. The (meth) acrylate includes acrylate and methacrylate. Furthermore, (meth) acrylonitrile includes acrylonitrile and methacrylonitrile.

[Production method of particle mixture]
FIG. 1 is a schematic view schematically showing an apparatus for producing a particle mixture according to an embodiment of the present invention. In this embodiment, a manufacturing apparatus 10 including a bead mill 100 as shown in FIG. 1 is used to manufacture a particle mixture containing inorganic particles, organic particles, and a dispersion medium.

  The manufacturing apparatus 10 includes a bead mill 100, a tank 200 even connected to the bead mill 100 by a pipe 210, and a pump 300 provided in the middle of the pipe 210. The manufacturing apparatus 10 has a structure capable of supplying the fluid composition stored in the tank 200 to the bead mill 100 by operating the pump 300.

  The bead mill 100 includes a vessel 110, and a pipe 210 is connected to the vessel 110. A filter 120 is provided in the vessel 110, and the space in the vessel 110 is partitioned into a crushing chamber 130 and a recovery chamber 140 by the filter 120.

  A rotor 150 is provided in the grinding chamber 130. The rotor 150 has a disk shape and is connected to a rotating shaft 160 that is rotationally driven by a driving device (not shown) as indicated by an arrow A1. For this reason, the rotor 150 is provided to be rotatable in the circumferential direction along with the rotation of the rotating shaft 160. Furthermore, a protrusion 151 is formed near the end of the rotor 150 so that the grinding medium 170 can be efficiently stirred by the rotation of the rotor 150.

In the pulverization chamber 130, a particulate dispersion medium 170 is accommodated. In the present embodiment, the number average particle size of the dispersion medium 170 is usually 0.1 mm or more, preferably 0.2 mm or more, more preferably 0.3 mm or more, and usually 3 mm or less, preferably 2 mm or less, More preferably, it is 1 mm or less. By using a dispersion medium 170 having a number average particle diameter in such a range and setting the peripheral speed of the rotor 150 to a predetermined range as described later, the primary particles of the organic particles and the inorganic particles are dispersed during the dispersion treatment. These secondary particles can be solved well while preventing destruction. Moreover, by making the number average particle diameter of the dispersion medium 170 equal to or greater than the lower limit of the above range, the destruction of the inorganic particles and the organic particles can be more stably prevented. Moreover, by making it below the upper limit value, secondary particles can be crushed and particles can be efficiently dispersed.
The number average particle size of the dispersion medium 170 can be measured by a laser diffraction particle size distribution measuring device (trade name “SALD-2300” manufactured by Shimadzu Corporation).

  Examples of the material forming the dispersion medium 170 include zirconium oxide, magnesia stabilized zirconium oxide, yttrium stabilized zirconium oxide, zirconium silicate, glass, stainless steel, titania, and alumina. Moreover, the material of the dispersion medium 170 may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The density of the material forming the dispersion medium 170 is preferably 1.5 g / cm ³ or more, more preferably 2.0 g / cm ³ or more, particularly preferably 2.5 g / cm ³ or more, preferably 9.0 g. / Cm ³ or less, more preferably 8.0 g / cm ³ or less, and particularly preferably 7.0 g / cm ³ or less. By setting the density of the material forming the dispersion medium 170 to be equal to or higher than the lower limit of the above range, the secondary particles of the organic particles can be effectively solved. Moreover, destruction of the primary particle of an inorganic particle and an organic particle can be prevented more reliably by setting it as an upper limit or less.

  The filling rate of the dispersion medium 170 in the pulverizing chamber 130 is preferably 40% by volume or more, more preferably 50% by volume or more, particularly preferably 60% by volume or more, and preferably 98% by volume or less, more preferably 95%. It is not more than volume%, particularly preferably not more than 90 volume%. By setting the filling rate to be equal to or higher than the lower limit value of the above range, the dispersion can be efficiently performed. In addition, by setting the upper limit value or less, a sufficient space in which the dispersion medium 170 moves around in the pulverizing chamber 130 can be secured. Here, the filling rate of the dispersion medium 170 is obtained by calculating the filling volume of the dispersion medium 170 by dividing the weight of the dispersion medium 170 by the bulk density of the dispersion medium 170 and dividing the filling volume by the volume of the grinding chamber 130. Can be sought.

  The recovery chamber 140 is a chamber for recovering a particle mixture containing inorganic particles and organic particles that have been dissolved in the pulverization chamber 130 into primary particles. Although the grinding media 170 cannot pass through the filter 120, inorganic particles and organic particles can pass through the filter 120. Therefore, the bead mill 100 has a configuration in which the particle mixture can flow into the recovery chamber 140.

  A cooler 180 is provided on the outer periphery of the vessel 110 as a temperature adjusting device. The cooler 180 is provided with a pipe (not shown) through which water can pass, and the vessel 110 can be cooled by passing water through the pipe, and thus the inside of the grinding chamber 130 can be cooled.

In the manufacturing method of the particle mixture which concerns on this embodiment, a particle mixture is manufactured with the following procedures using the manufacturing apparatus 10 mentioned above.
First, inorganic particles, organic particles, and a dispersion medium are prepared as raw materials for the particle mixture. At this time, the inorganic particles, the organic particles and the dispersion medium may be prepared separately, but usually the inorganic particles are prepared in a state of a dispersion dispersed in the dispersion medium.

  Inorganic particles are particles formed of an inorganic material. Examples of the inorganic particles include metal oxides such as zirconia, titania, tin oxide, and antimony pentoxide; titanates such as barium titanate and strontium titanate; CdS, CdSe, ZnSe, CdTe, ZnS, HgS, Examples thereof include sulfides such as HgSe, PdS, and SbSe, selenides, and tellurides. Moreover, an inorganic particle may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

As the inorganic particles, those having a particle diameter smaller than that of the dispersion medium and the organic particles are usually used. The volume average particle diameter of the primary particles of the inorganic particles is preferably 1 nm or more, more preferably 3 nm or more, particularly preferably 5 nm or more, preferably 200 nm or less, more preferably 150 nm or less, and particularly preferably 100 nm or less. By keeping the volume average particle diameter of the primary particles of the inorganic particles in such a range, for example, the refractive index can be appropriately adjusted, and desired optical characteristics are expressed in the optical pressure-sensitive adhesive layer using the produced particle mixture. be able to.
Here, the volume average particle diameter of the primary particles indicates the volume average particle diameter of the particles that are not aggregated. Further, the volume average particle diameter of the particles represents a particle diameter at which the cumulative volume calculated from the small diameter side is 50% in the particle diameter distribution measured by the laser diffraction method.

  The concentration of inorganic particles in the composition subjected to the dispersion treatment (hereinafter sometimes referred to as “raw material mixture” as appropriate) is preferably 10% by weight or more, more preferably 15% by weight or more, and particularly preferably 20% by weight. It is above, preferably 70% by weight or less, more preferably 60% by weight or less, and particularly preferably 50% by weight or less. By making the density | concentration of an inorganic particle more than the lower limit of the said range, an adhesive composition can obtain sufficient viscosity after mixing with an adhesive material. Moreover, mixing with an adhesive material can be made easy by using below an upper limit.

  The organic particles are particles formed of an organic material. Examples of the organic particle material include polymers such as silicone, acrylic polymer, and polystyrene. Moreover, one type of organic particles may be used alone, or two or more types may be used in combination at any ratio.

  As the organic particles, those having a particle size smaller than that of the dispersion medium and larger than that of the inorganic particles are usually used. The volume average particle diameter of the primary particles of the organic particles is preferably 0.1 μm or more, more preferably 0.3 μm or more, particularly preferably 0.5 μm or more, preferably 10 μm or less, more preferably 5 μm or less, particularly preferably. Is 3 μm or less. By keeping the volume average particle diameter of the primary particles of the organic particles in such a range, for example, light scattering becomes possible, and desired optical characteristics are expressed in the optical adhesive layer using the produced particle mixture. Can do.

Furthermore, the particle size ratio (inorganic particles / organic particles) between the volume average particle size of the primary particles of the inorganic particles and the volume average particle size of the primary particles of the organic particles is preferably within a predetermined range. Specifically, the particle size ratio is preferably 1.0 × 10 ⁻⁴ or more, more preferably 1.0 × 10 ⁻³ or more, particularly preferably 5.0 × 10 ⁻³ or more, preferably Is 0.8 or less, more preferably 0.5 or less, and particularly preferably 0.1 or less. By setting the particle size ratio to be equal to or higher than the lower limit of the above range, precipitation of the organic particles in the particle mixture can be reduced. Moreover, the destruction by the bead mill of an inorganic particle can be reduced by making it below an upper limit.

  The concentration of the organic particles in the raw material mixture is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, particularly preferably 1.0% by weight or more, preferably 20% by weight or less, more preferably It is 10 wt% or less, particularly preferably 5 wt% or less. By setting the concentration of the organic particles to be equal to or higher than the lower limit of the above range, sufficient light diffusibility can be secured when the optical adhesive layer is formed. Moreover, sufficient adhesiveness can be obtained in the optical pressure-sensitive adhesive layer by setting it to the upper limit value or less.

  The weight ratio (inorganic particles / organic particles) between the amount of inorganic particles and the amount of organic particles is preferably within a predetermined range. Specifically, the weight ratio is preferably 3 or more, more preferably 5 or more, particularly preferably 10 or more, preferably 200 or less, more preferably 150 or less, and particularly preferably 100 or less. By setting the weight ratio to be equal to or higher than the lower limit of the above range, sufficient adhesiveness can be obtained in the optical adhesive layer. Moreover, when it is set to the upper limit value or less, sufficient light diffusibility can be ensured when the optical adhesive layer is formed.

  Examples of the dispersion medium include ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; methanol, ethanol, isopropyl alcohol, n-butanol, iso-butanol, and the like. Alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, etc .; ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether Esters such as acetate and propylene glycol monoethyl ether acetate; dimethylform Bromide, N, N- dimethyl acetoacetamide, amides such as N- methyl pyrrolidone; and water. Moreover, a dispersion medium may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  In addition, the raw material mixture may further contain optional components in combination with the inorganic particles, organic particles, and dispersion medium described above, as long as the effects of the present invention are not significantly impaired. Examples of such optional components include a dispersant. The dispersant has an action of coordinating on the surface of inorganic particles or organic particles to prevent aggregation of these particles, and is particularly effective in preventing aggregation of inorganic particles.

  The prepared inorganic particles, organic particles and dispersion medium, and optional components used as necessary are placed in the tank 200 and mixed. Usually, stirring is performed in the tank 200. Although the inorganic particles and the organic particles are dispersed to some extent by stirring, the organic particles that tend to aggregate are usually aggregated into secondary particles. On the other hand, the inorganic particles are often primary particles in the tank 200 when prepared in the state of a dispersion previously dispersed in a dispersion medium. Thus, a composition containing inorganic particles, organic particles, and a dispersion medium, in which inorganic particles or organic particles are aggregated, is stored in the tank 200 as a raw material composition 400 to be subjected to dispersion treatment. It is done.

  Thereafter, the rotor 150 of the bead mill 100 is rotated. Further, with the rotation of the rotor 150 maintained, the pump 300 is operated to continuously supply the raw material mixture 400 in the tank 200 into the grinding chamber 130 of the bead mill 100. Thereby, the step of supplying the inorganic particles, the organic particles and the dispersion medium into the grinding chamber 130 and the step of rotating the rotor 150 in a state where the inorganic particles, the organic particles and the dispersion medium are in the grinding chamber 130 are performed.

  In the pulverization chamber 130, organic particles and inorganic particles are dispersed by the rotor 150 and the dispersion medium 170. That is, the dispersion medium 170 is agitated by the rotation of the rotor 150. A shearing force is applied to the inorganic particles and the organic particles by the stirred dispersion medium 170. By this shearing force, the secondary particles of inorganic particles and organic particles are solved and become primary particles. Moreover, since these inorganic particles and organic particles are stirred by the dispersion medium 170, they are uniformly dispersed in the dispersion medium.

  The peripheral speed of the rotor 150 during rotation of the rotor 150 is usually 0.2 m / second or more, preferably 0.4 m / second or more, more preferably 0.8 m / second or more, and usually 3.0 m / second. Hereinafter, it is preferably 2.5 m / sec or less, more preferably 2.0 m / sec or less. Here, the circumferential speed of the rotor 150 refers to the speed of the outer edge portion 152 of the rotor 150. By using the dispersion medium 170 that keeps the peripheral speed of the rotor 150 in such a range and has a number average particle diameter in a predetermined range as described above, the primary particles of the organic particles and the inorganic particles are dispersed during the dispersion treatment. These secondary particles can be solved well while preventing destruction. Further, by making the peripheral speed of the rotor 150 equal to or higher than the lower limit of the above range, the secondary particles can be efficiently crushed and the particles can be dispersed. Moreover, destruction of an inorganic particle and an organic particle can be prevented more stably by setting it as an upper limit or less.

  The peripheral speed of the rotor 150 may be constant or may vary as long as it is within the above range.

  When the raw material mixture 400 is supplied from the tank 200 to the bead mill 100, the flow rate of the raw material mixture 400 flowing into the crushing chamber 130 is preferably within a desired range. Specifically, when the volume of the crushing chamber 130 is Vml, the flow rate of the raw material mixture 400 is preferably 0.05 × Vml / min or more, more preferably 0.1 × Vml / min or more, and particularly preferably 0. .15 × Vml / min or more, preferably 0.5 × Vml / min or less, more preferably 0.3 × Vml / min or less, and particularly preferably 0.2 × Vml / min or less. Excessive dispersion processing can be prevented by setting the flow rate of the raw material mixture 400 to be equal to or higher than the lower limit of the above range. Moreover, a uniform dispersion | distribution process can be performed by making it into below an upper limit.

  Further, when the rotor 150 is rotated, heat may be generated due to friction of the dispersion medium 170. Therefore, it is preferable to cool the inside of the crushing chamber 130 by passing water through the piping of the cooler 180.

  The time for performing the dispersion treatment can be appropriately set according to factors such as the types and composition ratios of the inorganic particles, the organic particles, and the dispersion medium. Usually, in the manufacturing method according to the present embodiment, dispersion processing can be performed efficiently, so that dispersion in a short time is possible.

  After the secondary particles are unraveled in the pulverization chamber 130, the inorganic particles and organic particles that have become primary particles, and the dispersion medium are sent to the recovery chamber 140 through the filter 120, and the particles are mixed outside the bead mill 100. Is sent to. This particle mixture includes non-aggregated inorganic particles, non-aggregated organic particles, and a dispersion medium. Further, the primary particles of the inorganic particles and the organic particles are not broken by the dispersion treatment by the bead mill 100. Therefore, the volume average particle diameter of the primary particles of the inorganic particles contained in the produced particle mixture can be made substantially the same as the volume average particle diameter of the primary particles of the inorganic particles contained in the raw material mixture. Moreover, the volume average particle diameter of the primary particles of the organic particles contained in the produced particle mixture can be made substantially the same as the volume average particle diameter of the primary particles of the organic particles contained in the raw material mixture.

  In general, when particles are dispersed by a dispersing device such as a bead mill, it is often the purpose to make the primary particles as small as possible by breaking the primary particles. However, in the above-described embodiment, the secondary particles are solved without destroying the primary particles. Therefore, the change in the particle size distribution of the primary particles can be reduced before and after the dispersion treatment. In particular, in a composition containing a plurality of types of particles having different compositions and physical properties of organic particles and inorganic particles, secondary particles can be solved while suppressing changes in the particle size distribution of the primary particles. This is significant in efficiently producing the composition.

  Furthermore, the particle size distribution of the primary particles of the inorganic particles and the organic particles in the raw material mixture is usually maintained in the produced particle mixture. Therefore, when inorganic particles and organic particles contained in the raw material mixture are those having a sharp peak of the particle size distribution of the primary particles, the particle size of the primary particles of the inorganic particles and organic particles in the produced particle mixture The distribution remains sharp. This advantage is in contrast to the fact that when the primary particle breakage occurs as in the conventional dispersion treatment technique, the peak of the particle size distribution of the primary particle in the produced particle mixture is broad. Is. Here, generally, the sharp peak of the particle size distribution of the particles means that the particle sizes of the particles are uniform. Therefore, the above-described method for producing a particle mixture is significant in that it enables production of a particle mixture including inorganic particles having a uniform primary particle size and organic particles having a uniform primary particle size. .

The method for producing a particle mixture according to an embodiment of the present invention is as described above, but the present invention may be further modified.
For example, the structure of the mill may be changed. As a specific example, the shape of the rotor 150 is not limited to the disc shape as in the above embodiment, but may be a rod shape, a blade shape, or the like. In the manufacturing method described above, mills having various configurations can be used. For example, commercially available bead mills sold by manufacturers such as Ashizawa Finetech, Kotobuki Kogyo, and Imex may be used.

  Further, for example, the dispersion process by the bead mill 100 may be repeated twice or more by returning the particle mixture sent from the recovery chamber 140 into the tank 200. Thereby, the amount of secondary particles remaining in the particle mixture can be reduced. Thus, it is preferable to repeatedly perform the dispersion treatment by circulating the raw material mixture or the particle mixture between the bead mill 100 and the tank 200 because a particle mixture having a high degree of particle dispersion can be efficiently performed.

  Further, when the raw material mixture or the particle mixture is circulated between the bead mill 100 and the tank 200, some components such as inorganic particles, organic particles, and a dispersion medium may be appropriately added to the raw material mixture or the particle mixture. Good. For example, the composition may be adjusted by adding a volatilized dispersion medium during the circulation.

  In addition, the supply of the raw material mixture 400 to the bead mill 100 may be performed collectively as well as continuously as in the above-described embodiment. That is, instead of supplying the raw material mixture 400 by a flow as in the above-described embodiment, the dispersion process may be performed in batches.

[Optical adhesive composition]
The optical pressure-sensitive adhesive composition according to the present invention (hereinafter sometimes referred to as “adhesive composition” as appropriate) includes the particle mixture and the pressure-sensitive adhesive material produced by the production method according to the present invention. Therefore, the pressure-sensitive adhesive composition according to the present invention includes a pressure-sensitive adhesive material, non-aggregated inorganic particles, non-aggregated organic particles, and a dispersion medium.

  As an adhesive material, a polymer is usually used. In the adhesive composition, the polymer as the adhesive material is usually dissolved in the dispersion medium. Examples of such a polymer include acrylic polymer, polyurethane, polyvinyl alkyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, and polyvinyl acetate. One of these may be used alone, or two or more of these may be used in combination at any ratio.

  Among these, an acrylic polymer excellent in properties such as transparency, weather resistance, and heat resistance is preferable. An acrylic polymer is a polymer containing a structural unit having a structure formed by polymerizing an acrylic monomer. Examples of such an acrylic polymer include a polymer obtained by polymerizing an acrylic monomer; or a polymer obtained by polymerizing a mixture (monomer mixture) of an acrylic monomer and a monomer copolymerizable therewith.

  Examples of acrylic monomers include alkyl (meth) acrylates. The average carbon number of the alkyl group of the alkyl (meth) acrylate is preferably 1 or more, more preferably 3 or more, preferably 12 or less, more preferably 8 or less. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate. Moreover, these may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  Preferred examples of the monomer that can be copolymerized with the acrylic monomer include a monomer having a functional group, a nitrogen atom-containing monomer, and a modified monomer.

  Examples of the monomer having a functional group include a monomer having a carboxyl group, a monomer having a hydroxyl group, and a monomer having an epoxy group. Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and itaconic acid. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, and N-methylol (meth) acrylamide. Examples of the monomer having an epoxy group include glycidyl (meth) acrylate. When the acrylic monomer and the monomer having a functional group are used in combination, the ratio of the two is 100% by weight of the total of the acrylic monomer and the monomer having a functional group, and the acrylic monomer is 60% by weight to 99.8% by weight. It is preferable that the monomer which has a functional group is 40 to 0.2 weight%.

  Examples of nitrogen atom-containing monomers include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, (meth) acetonitrile, vinylpyrrolidone, N- Examples include cyclohexylmaleimide, itaconimide, and N, N-dimethylaminoethyl (meth) acrylamide. When the acrylic monomer and the nitrogen atom-containing monomer are used in combination, the ratio of the two is such that the total of the acrylic monomer and the nitrogen atom-containing monomer is 100% by weight, the acrylic monomer is 60% by weight to 99.8% by weight, and the nitrogen atom The content monomer is preferably 40% by weight to 0.2% by weight.

  Examples of modifying monomers include vinyl acetate and styrene. When the acrylic monomer and the modified monomer are used in combination, the ratio of the two is such that the total of the acrylic monomer and the modified monomer is 100% by weight, the acrylic monomer is 60% by weight to 99.8% by weight, It is preferable that it is 40 weight%-0.2 weight%.

  One of these monomers that can be copolymerized with the acrylic monomer may be used alone, or two or more thereof may be used in combination at any ratio.

  The amount of the adhesive material in the adhesive composition is preferably 3% by weight or more, more preferably 5% by weight or more, particularly preferably 8% by weight or more, preferably 30% by weight or less, more preferably 25% by weight. Hereinafter, it is particularly preferably 20% by weight or less. By making the amount of the adhesive material equal to or more than the lower limit of the above range, the adhesive strength of the optical adhesive layer can be increased. Moreover, a favorable surface shape can be obtained at the time of application | coating of an adhesive composition by setting it as an upper limit or less.

  In the pressure-sensitive adhesive composition, the inorganic particles are not aggregated and become primary particles. Further, the primary particles are not destroyed by the dispersion treatment described above. For this reason, the volume average particle diameter of the inorganic particles contained in the adhesive composition can be within the same range as described above as the volume average particle diameter of the primary particles of the inorganic particles. Therefore, the inorganic particles can impart desired optical properties according to the particle diameter to the adhesive composition, and for example, can increase the refractive index of the adhesive composition.

  The amount of the inorganic particles in the adhesive composition is preferably 50 parts by weight or more, more preferably 80 parts by weight or more, particularly preferably 100 parts by weight or more, preferably 300 parts by weight with respect to 100 parts by weight of the adhesive material. Hereinafter, it is more preferably 250 parts by weight or less, and particularly preferably 200 parts by weight or less. The refractive index of the optical pressure-sensitive adhesive layer can be increased by setting the amount of inorganic particles to be equal to or higher than the lower limit of the above range. Moreover, the adhesive force of the optical adhesive layer can be increased by setting it to the upper limit value or less.

  In the adhesive composition, the organic particles are not agglomerated but are primary particles. Further, the primary particles are not destroyed by the dispersion treatment described above. For this reason, the volume average particle diameter of the organic particles contained in the adhesive composition can fall within the same range as described above as the volume average particle diameter of the primary particles of the organic particles. Therefore, the organic particles can impart desired optical properties according to the particle diameter to the adhesive composition, and for example, can impart light scattering properties to the adhesive composition.

  The amount of the organic particles in the adhesive composition is preferably 1 part by weight or more, more preferably 3 parts by weight or more, particularly preferably 5 parts by weight or more, and preferably 50 parts by weight with respect to 100 parts by weight of the adhesive material. Below, more preferably 30 parts by weight or less, particularly preferably 20 parts by weight or less. Sufficient light diffusibility can be ensured by setting the amount of organic particles to be equal to or greater than the lower limit of the above range. Moreover, the adhesive force of the optical adhesive layer can be increased by setting it to the upper limit value or less.

  In the adhesive composition, the dispersion medium contained in the particle mixture may be used. Further, for example, in order to adjust the concentration of the solid content of the adhesive composition, a dispersion medium may be further mixed in addition to the dispersion medium contained in the particle mixture. Here, the solid content of the adhesive composition refers to a substance remaining after drying the adhesive composition.

  The amount of the dispersion medium in the pressure-sensitive adhesive composition is preferably set so that the solid content concentration of the pressure-sensitive adhesive composition falls within a desired range. The specific range of the solid content concentration of the pressure-sensitive adhesive composition is preferably 10% by weight or more, more preferably 15% by weight or more, particularly preferably 20% by weight or more, and preferably 50% by weight or less. Is 45% by weight or less, particularly preferably 40% by weight or less. By setting the solid content concentration of the pressure-sensitive adhesive composition to be equal to or higher than the lower limit of the above range, an optical pressure-sensitive adhesive layer having a sufficient thickness can be obtained when the pressure-sensitive adhesive composition is applied. Moreover, a favorable surface shape can be obtained at the time of application | coating of an adhesive composition by setting it as an upper limit or less.

Moreover, the adhesive composition may contain arbitrary components other than an adhesive material, an inorganic particle, an organic particle, and a dispersing agent.
For example, the adhesive composition may contain a plasticizer. By using a plasticizer, the viscosity of the pressure-sensitive adhesive composition can be reduced, and the pressure-sensitive adhesive force of the optical pressure-sensitive adhesive layer formed using this pressure-sensitive adhesive composition can be increased.

  Examples of the plasticizer include polybutene, vinyl ether compound, polyether compound (including polyalkylene oxide and functionalized polyalkylene oxide), ester compound, polyol compound (for example, glycerin), petroleum resin, hydrogenated petroleum resin, and styrene. System compounds (for example, α-methylstyrene) and the like. Of these, ester compounds are preferred because of their good miscibility with adhesive materials, and ester compounds containing an aromatic ring such as benzoic acid and phthalic acid are particularly preferred.

Examples of the benzoic acid ester that can be used as the plasticizer include diethylene glycol dibenzoate, dipropylene glycol dibenzoate, benzyl benzoate, and 1,4-cyclohexanedimethanol dibenzoate. Particularly preferred among these are, for example, benzoic acid ester compounds such as dipropylene glycol dibenzoate and benzyl benzoate; dimethyl phthalate, diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, and ethyl phthalyl ethyl glycolate. Phthalic acid ester compounds. Furthermore, as an example of a commercially available plasticizer, a brand name "BENZOFLEX 9-88SG" (made by Eastman) can be mentioned.
Moreover, a plasticizer may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

  The amount of the plasticizer in the adhesive composition is preferably 1 part by weight or more, more preferably 5 parts by weight or more, preferably 35 parts by weight or less, more preferably 100 parts by weight of the adhesive material. 30 parts by weight or less.

  Moreover, the adhesive composition may contain the silane coupling agent. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyl. Trimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxy Lan, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane Silane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, Examples include 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, and 3-isocyanatopropyltriethoxysilane. Moreover, as an example of a commercially available silane coupling agent, a brand name "KBM-803" (made by Shin-Etsu Chemical Co., Ltd.) can be mentioned. A silane coupling agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The amount of the silane coupling agent in the adhesive composition is preferably 0.05 parts by weight or more, more preferably 0.2 parts by weight or more, and preferably 10 parts by weight with respect to 100 parts by weight of the adhesive material. Part or less, more preferably 5 parts by weight or less.

  Furthermore, the adhesive composition may contain a curing agent. As a hardening | curing agent, an isocyanate compound can be mentioned, for example. Specific examples of the curing agent include addition polymers of isocyanate containing isophorone diisocyanate (for example, trade name “NY-260A”, manufactured by Mitsubishi Chemical Corporation). A hardening | curing agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  The amount of the curing agent in the adhesive composition is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and preferably 10 parts by weight or less with respect to 100 parts by weight of the adhesive material. More preferably, it is 5 parts by weight or less.

  The pressure-sensitive adhesive composition can be produced by mixing the particle mixture according to the present invention, the pressure-sensitive material, and components other than these as necessary simultaneously or in any order.

[Optical adhesive layer]
The optical pressure-sensitive adhesive layer according to the present invention is a layer formed of a material obtained by drying the pressure-sensitive adhesive composition according to the present invention. That is, the optical pressure-sensitive adhesive layer according to the present invention is a layer formed by the solid content of the pressure-sensitive adhesive composition according to the present invention. Therefore, the optical pressure-sensitive adhesive layer according to the present invention can contain inorganic particles, organic particles, and a pressure-sensitive adhesive material in the same composition as that in the pressure-sensitive adhesive composition.

  In the optical pressure-sensitive adhesive layer, the inorganic particles and the organic particles are not aggregated and are dispersed as primary particles. Further, the primary particles are not destroyed by the dispersion treatment described above. Therefore, the volume average particle diameter of the inorganic particles in the optical pressure-sensitive adhesive layer is within the same range as described above as the volume average particle diameter of the primary particles of the inorganic particles. Therefore, the inorganic particles can impart desired optical characteristics corresponding to the particle diameter to the optical pressure-sensitive adhesive layer. For example, the refractive index of the optical pressure-sensitive adhesive layer can be increased. Furthermore, the volume average particle diameter of the organic particles in the optical pressure-sensitive adhesive layer is within the same range as described above as the volume average particle diameter of the primary particles of the organic particles. Therefore, the organic particles can impart desired optical characteristics corresponding to the particle diameter to the optical pressure-sensitive adhesive layer. For example, the organic particles can impart light scattering properties to the optical pressure-sensitive adhesive layer.

  The optical pressure-sensitive adhesive layer can be formed, for example, by applying a pressure-sensitive adhesive composition to the surface of a desired member and drying it. As described above, the optical pressure-sensitive adhesive layer thus obtained can contain components contained in the pressure-sensitive adhesive composition, but some of the components may be changed by reaction, and some of the components may be volatilized. And may disappear. For example, reactive components such as a silane coupling agent and a curing agent may react to form another substance by drying, or the dispersion medium may volatilize and disappear.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.
In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.

[Method for evaluating the state of inorganic particles]
The particle size distribution of the inorganic particles was measured with a dynamic light scattering nanotrack particle size analyzer ("UPA-EX" manufactured by Nikkiso Co., Ltd.).
In the particle size distribution of the inorganic particles, the difference between the integrated 50% particle size of the inorganic particles before the dispersion treatment (that is, the volume average particle size) and the integrated 50% particle size of the inorganic particles after the dispersion treatment is calculated. The amount of change in the integrated 50% particle size of the inorganic particles before and after the dispersion treatment was used. When this amount of change was 30% or less of the cumulative 50% particle size of the inorganic particles before the dispersion treatment, it was judged that there was no particle breakage or aggregation, and was indicated as “good”. Further, when the amount of change exceeded 30% of the 50% cumulative particle size of the inorganic particles before the dispersion treatment, it was judged that there was particle breakage or aggregation, and indicated as “bad”.

[Method for evaluating the state of organic particles]
The particle size distribution of the organic particles was measured with a particle size analyzer (“9320HRA” manufactured by Nikkiso Co., Ltd.).
In the particle size distribution of the organic particles after the dispersion treatment, when the half width of the peak of the particle size distribution is 1.05 times or less of the particle size of the peak, it is determined that there is no particle breakage or aggregation. “Good”. Further, when the half width of the peak of the particle size distribution exceeded 1.05 times the particle size of the peak, it was judged that there was particle breakage or aggregation, and indicated as “bad”.

[Method for evaluating surface state of adhesive layer]
The surface of the adhesive layer was visually observed. As a result of observation, it was judged that the glossy surface was smooth and the surface of the adhesive layer was judged as smooth. In addition, those with no gloss were judged as having a concave portion and a convex portion on the surface of the pressure-sensitive adhesive layer and indicated as “bad”.

[Example 1]
(Preparation of bead mill)
A bead mill (“RMH-03” manufactured by Imex Co., Ltd.) was prepared, which was provided with a pulverization chamber, a rotor rotatably provided in the pulverization chamber, and a pulverization medium accommodated in the pulverization chamber. The volume of the grinding chamber of this bead mill was 310 cm ³ . In this bead mill, zirconia beads (number average particle diameter 0.3 mm) were used as a grinding medium. The filling rate of the grinding medium in the grinding chamber was 80%. This bead mill was provided with a slit at the downstream end in the flow direction of the raw material mixture, and the raw material mixture that had been subjected to the dispersion treatment could be taken out through the slit.

(Preparation of raw material mixture)
An inorganic particle dispersion (Solar “ZR-010”) containing zirconia particles as inorganic particles and methyl ethyl ketone as a dispersion medium was prepared. The volume average particle diameter of the primary particles of the inorganic particles was 15 nm. Moreover, the density | concentration of the inorganic particle in an inorganic particle dispersion liquid was 30 weight%.

  Silicone particles (“XC-99” manufactured by Momentive Performance Materials, Inc.) were prepared as organic particles. The volume average particle diameter of the organic particles was 0.7 μm.

  A tank was charged with 600 g of inorganic particle dispersion and 10.6 g of organic particles, and stirred. As a result, a raw material mixture in which inorganic particles and organic particles were dispersed in the dispersion medium was obtained. In this raw material mixture, the inorganic particles are well dispersed without being aggregated, but the organic particles are aggregated to form secondary particles.

(Supply and dispersion of raw material mixture to grinding chamber)
The raw material mixture was continuously supplied into the grinding chamber of the bead mill by a pump. At this time, the flow rate of the raw material mixture when flowing into the bead mill was set to be 60 ml / min. Further, while supplying, the bead mill rotor was rotated to disperse the inorganic particles and the organic particles in the grinding chamber. Moreover, the raw material mixture which gave the grinding | pulverization process was taken out through the slit. That is, the inorganic particles and organic particles contained in the raw material mixture were dispersed by circulating the raw material mixture in the grinding chamber of the bead mill with the rotor rotated. At this time, the circumferential speed of the rotor was 0.47 m / sec. Moreover, the raw material mixture was made to distribute | circulate the bead mill over 10 minutes per dispersion process.

  By performing the dispersion treatment three times, a particle mixture containing inorganic particles, organic particles and a dispersion medium was obtained over a total of 30 minutes. About the particle | grain mixture obtained in this way, the state of an inorganic particle and the state of an organic particle were evaluated in the way mentioned above.

(Manufacture of optical adhesive composition)
As the adhesive material, an acrylic adhesive (trade name “OC-3447”, manufactured by Seiden Chemical Co., Ltd., solid content: 30%) was used.

  100 parts by weight of the acrylic pressure-sensitive adhesive (that is, 30 parts by weight of the pressure-sensitive adhesive material and 70 parts by weight of the solvent) was mixed with 190 parts by weight of the particle mixture to obtain a pressure-sensitive adhesive composition.

  A polyethylene terephthalate film (manufactured by Toray, trade name “U34”) having a thickness of 100 μm was prepared as a substrate. On the surface of this base material, the said adhesive composition was apply | coated so that the thickness after drying might be set to 20 micrometers, and it was made to dry, and the adhesion layer for optics was formed. The surface state of the obtained optical pressure-sensitive adhesive layer was evaluated in the manner described above.

[Examples 2 to 8 and Comparative Examples 1 to 5]
As shown in Table 1 and Table 2 below, except for changing the material of the grinding media, the number average particle size of the grinding media, the peripheral speed of the rotor, the type of inorganic particles, the type of organic particles, and the processing time In the same manner as in Example 1, the particle mixture, the adhesive composition, and the adhesive layer were produced and evaluated.
Whether or not to end the distributed processing was determined as follows. Sampling the dispersion treatment liquid (liquid mixture delivered from the bead mill after being subjected to dispersion treatment), measuring the particle size distribution of the organic particles with a particle size analyzer, and the peaks that are secondary particles disappear Thus, the dispersion treatment was terminated when only the peak indicating the primary particle size was reached.
Here, the titania particles used as inorganic particles in Example 6 were “NOD-742GTF” manufactured by Nagase ChemteX Corporation, and the volume average particle diameter of the primary particles was 15 nm.
The acrylic resin particles used as organic particles in Example 7 were “MP series” manufactured by Soken Chemical Co., Ltd., and the primary particles had a volume average particle diameter of 0.8 μm.
Furthermore, as the glass beads used as the dispersion medium in Example 8, those having a number average particle diameter of 0.36 mm were used.

[result]
Tables 1 and 2 show the results of Examples and Comparative Examples. In Tables 1 and 2, the meanings of the abbreviations are as follows.
Bead material: The material of the grinding media.
Bead diameter: Number average particle diameter of grinding media.
Peripheral speed: The peripheral speed of the rotor.
SIL: Silicone.
ACR: Acrylic resin.
Processing time: Total time for which distributed processing was performed. Since it is 10 minutes per distributed process, for example, a processing time of 20 minutes indicates that the distributed process has been performed twice.

[Consideration]
In Comparative Example 1, the circumferential speed of the rotor is slow, processing takes time, and efficient distributed processing cannot be performed. In Comparative Examples 2 and 3, the peripheral speed of the rotor is high, and the organic particles or inorganic particles are destroyed. In Comparative Example 4, the number average particle size of the grinding medium is small, and the inorganic particles are broken. Furthermore, in Comparative Example 5, the number average particle size of the grinding medium is large, and it takes time for the treatment, and an efficient dispersion treatment cannot be performed.

On the other hand, in Examples 1-8, efficient dispersion processing can be performed in a short time without causing destruction of inorganic particles and organic particles.
From the above results, according to the present invention, a particle mixture containing non-aggregated organic particles, non-aggregated inorganic particles and a dispersion medium, while preventing the primary particles from being destroyed when dispersing the organic particles and the inorganic particles, It was confirmed that a method for producing a particle mixture that can be efficiently produced can be realized.

DESCRIPTION OF SYMBOLS 10 Manufacturing apparatus 100 Bead mill 110 Vessel 120 Filter 130 Crushing chamber 140 Recovery chamber 150 Rotor 151 Rotor protrusion 152 Rotor outer edge 160 Rotating shaft 170 Grinding medium 180 Cooler 200 Tank 210 Piping 300 Pump 400 Raw material mixture

Claims (5)

A particle mixture including inorganic particles, organic particles, and a dispersion medium is produced using a mill including a grinding chamber, a rotor rotatably provided in the grinding chamber, and a particulate grinding medium accommodated in the grinding chamber. A manufacturing method comprising:
Supplying the inorganic particles, the organic particles and the dispersion medium into the grinding chamber;
Rotating the rotor with the inorganic particles, the organic particles and the dispersion medium in the grinding chamber,
The number average particle size of the grinding medium is 0.1 mm to 3 mm,
The method for producing a particle mixture, wherein a circumferential speed of the rotor during rotation of the rotor is 0.2 m / sec to 3.0 m / sec.   The manufacturing method of the particle mixture of Claim 1 whose volume average particle diameter of the primary particle of the said inorganic particle is 1 nm-200 nm.   The manufacturing method of the particle mixture of Claim 1 or 2 whose volume average particle diameter of the primary particle of the said organic particle is 0.1 micrometer-10 micrometers.   The adhesive composition for optics containing the particle mixture and the adhesive material which were manufactured with the manufacturing method as described in any one of Claims 1-3.   An optical pressure-sensitive adhesive layer formed from a material obtained by drying the optical pressure-sensitive adhesive composition according to claim 4.

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