JP4525583B2 - Method for producing zinc oxide dispersed paste - Google Patents

Description

  The present invention provides a stable dispersion method of fine zinc oxide.

  Zinc oxide is inexpensive (180-400 yen / kg) and has a low refractive index (about 2.0), so it has long been used as a filler for paints and inks, and as a vulcanizing agent for rubber. Furthermore, it is also used in antibacterial and antibacterial properties of zinc oxide. It is also characterized by providing a highly transparent film because of its low refractive index. For these applications, zinc oxide having a relatively large average primary particle size (0.5 to 10 μm), which is generally referred to as zinc white, is used.

  At this average primary particle size level, there is no need to care about the activity of the particle surface, and it is not necessary to bring out further functions as fine particles, so the usual dispersion technology used in paint, ink and rubber kneading is applied. Has been put to practical use.

  On the other hand, with (ultra) fine zinc oxide (having an average primary particle size of about 300 nm or less), the activity of the particle surface becomes extremely strong as the particle surface area increases rapidly, and in combination with the fine particles, dispersion and mixing are performed. Is extremely difficult. In other words, even if we were able to disperse well, in other words, even if particles with the expected particle size were obtained, the dispersion (paste), paint, ink, etc. would separate and settle in a relatively short time. The level was far from practical. Furthermore, thixotropic ones such as cosmetics and ointments have been put into practical use without being concerned about the viscosity. However, this thixotropic viscosity cannot be applied to industrial applications that require a coating process, and is not a solution to problems.

  Now, it is known that zinc oxide has ultraviolet absorption ability and conductive performance. In addition, it has a large reserve, is a relatively inexpensive material, and is a very useful material if it can be used stably. Furthermore, it is well known that the effect is dramatically improved if ultrafine zinc oxide is used, and ultrafine zinc oxide is usually used when expecting conductivity and ultraviolet absorption.

  Zinc oxide has an ultraviolet absorption capability and an ultraviolet blocking capability comparable to or better than benzophenone ultraviolet absorbers and benzotriazole ultraviolet absorbers, which are well-known organic ultraviolet absorbers. Furthermore, unlike these organic ultraviolet absorbers, zinc oxide does not disappear or expire over time and exhibits its function semipermanently.

Further, since it is a metal oxide, it has a function as a photocatalyst, a property as a semiconductor, and conductivity as is well known. The conductivity is not so much with zinc oxide alone, but the one with aluminum or gallium as a dopant has an electric resistance of 10 ⁰ to 10 ¹⁰ Ω · cm, and is expected as a transparent conductive material to replace ITO or ATO. .

  On the other hand, since zinc oxide has a high activity and an isoelectric point of about 9, it is known that paints and cosmetics containing zinc oxide are liable to cause deterioration, deterioration due to precipitation, separation, and reaction. Furthermore, it is known that the base material and the skin are easily affected by the activity of zinc oxide even in the applied state.

  In order to suppress this, a method has been proposed in which the surface of zinc oxide is coated with an oxide or hydroxide of aluminum, silicon, or an organic polysiloxane (see Patent Document 1).

According to the proposed technique, the activity of zinc oxide is suppressed, it can be stably dispersed in various media, and deterioration of zinc oxide over time is suppressed. However, it is well known that the dispersion stability of zinc oxide largely depends on the pigment dispersion method and cannot be sufficiently solved only by surface treatment. Also, even if a dispersion with good dispersion stability can be produced using a sand mill for dispersion as in this proposal, it is necessary to discuss whether it is stable when supplied as a coating material. In general, the dispersion stability of the dispersion is not the dispersion stability of the equal coating agent. In general, coating agents are often mixed with various solvents, isocyanate compounds, and curing agents such as epoxy resins to adjust the viscosity suitable for coating, and the isoelectric point of zinc oxide described above. In combination with (about 9), the dispersion stability deteriorates rapidly, and separation and gelation due to aggregation of zinc oxide are promoted.
JP 2002-87817 A

  When zinc oxide is stably dispersed and a zinc oxide-dispersed paste is produced, a method for producing a zinc oxide-dispersed paste having excellent storage stability has been desired.

  The present invention provides a method for dispersing zinc oxide, particularly fine zinc oxide having an average primary particle size of submicron size or less, for example, an average primary particle size of 200 nm or less.

  The zinc oxide-dispersed paste produced according to this production method is excellent in storage stability and is difficult to cause separation or precipitation over time.

  The paint, adhesive and the like containing the zinc oxide dispersion paste produced according to the present invention are excellent in storage stability without causing precipitation or separation.

  In addition, products coated with the paint, adhesive, etc., are protected from ultraviolet rays that cause deterioration because zinc oxide is uniformly dispersed in the coating film, and can be given antistatic properties and electrical conductivity. It becomes.

The present invention
(1) a method for producing a zinc oxide dispersion paste dispersed in a bead mill, the dispersion medium, toluene, ethyl acetate, butyl acetate, 1 - hexyl-3-methylimidazolium hexafluorophosphate at least DOO or selected When the shear rate is ¹ to 10 s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersion paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 50)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; A method for producing a zinc oxide dispersed paste which is at least one kind,
(2) a method for producing a zinc oxide dispersion paste dispersed in a bead mill, the dispersion medium, toluene, ethyl acetate, butyl acetate, 1 - hexyl-3-methylimidazolium hexafluorophosphate at least DOO or selected When the shear rate is 10 to 10 ² s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersion paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 30)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; The present invention relates to a method for producing at least one zinc oxide dispersion paste.

  In the method for producing a zinc oxide-dispersed paste of the present invention, as zinc oxide, the average primary particle diameter is preferably 0.5 nm or more in order to increase the transparency of a coating film or an adhesive film and to efficiently ensure ultraviolet absorption. It is desirable that the thickness be 200 nm or less, more preferably 0.5 nm to 150 nm, and still more preferably 0.5 nm to 100 nm.

  When the average primary particle diameter of zinc oxide exceeds 200 nm, the transparency of the coating film or the adhesive film tends to be impaired, and precipitation and aggregation tend to occur easily.

  On the other hand, when the average particle size is less than 0.5 nm, stable pigment dispersion may be very difficult. In addition, the pigment tends to re-aggregate and may thicken and gelate over time.

  Zinc oxide can be used without distinction whether it is surface-treated with an organic polysiloxane or the like or untreated.

  Furthermore, when zinc oxide uses aluminum or gallium as a dopant, it is possible not only to absorb ultraviolet rays but also to provide conductivity at the same time, which is useful when forming an antistatic or transparent conductive film. is there. Therefore, in the method for producing a zinc oxide-dispersed paste of the present invention, preferably, zinc oxide is conductive zinc oxide doped with aluminum, or zinc oxide is conductive zinc oxide doped with gallium.

In the manufacturing method of the zinc oxide dispersion paste of the present invention, the dispersion medium, toluene, ethyl acetate, butyl acetate, 1 - hexyl-3-methylimidazolium hexafluorophosphate. These dispersion media may be used alone or as a mixture of two or more.

  In the method for producing a zinc oxide-dispersed paste of the present invention, as a dispersion medium, esters such as ethyl acetate and butyl acetate are suitable because they have a high evaporation rate when applied to a polyester film or the like having a short processing time in an oven. is there.

  In addition, ionic liquids such as 1-hexyl-3-methylimidazolium hexafluorophosphate, combined with the electronic conductivity of zinc oxide, have the effect of further improving electrical conductivity while complementing each other. It is extremely effective and recommended for producing antistatic coatings and adhesives, electromagnetic shielding coatings and adhesives.

  In the method for producing a zinc oxide-dispersed paste of the present invention, zinc oxide is preferably dispersed in a dispersion medium by 10 to 50% by weight, more preferably 20 to 45% by weight, and further preferably 25 to 40% by weight. Is desirable. When the zinc oxide concentration is less than 10% by weight, not only the zinc oxide dispersion efficiency is poor, but also it may be difficult to increase the zinc oxide concentration in the film, and sufficient UV absorption and conductivity are obtained. It may not be possible. When zinc oxide exceeds 50% by weight, the viscosity during pigment dispersion tends to be high, and thixotropic properties tend to be obtained, and pigment dispersion tends to be insufficient.

In the method for producing a zinc oxide-dispersed paste of the present invention, as the pigment dispersant, nonionic surfactants such as polyoxyethylene glycol and polyoxyethylene alkylphenyl ether, polyoxyethylene glycol alkylphenyl ether sulfate, polyester poly An anionic surfactant such as a carboxylate, a polyester having an amino group, an amide group and a carboxylic acid group, and a polyester polyamidoamine salt are used .

  Zinc oxide has an isoelectric point of about 9 and an average primary particle diameter of preferably 200 nm or less, so that it can be made as fine as possible in the pigment dispersion step and stabilized as a pigment dispersant. High molecular weight is recommended. From this viewpoint, composite pigment dispersants such as high molecular weight polyesters and high molecular weight polyester polyamidoamine salts having amino groups, amide groups and carboxylic acid groups at the same time are desirable. When a pigment dispersant that does not have an amino group, amide group, or carboxyl group and does not have a high molecular weight is used, zinc oxide tends to cause gradual aggregation (hereinafter also referred to as flocculation), and storage stability and pot Life tends to get worse.

  The pigment dispersant is preferably blended in an amount of 2 to 50 phr, more preferably 5 to 50 phr, and still more preferably 8 to 40 phr with respect to zinc oxide. When the blending amount of the pigment dispersant is less than 2 phr, since the zinc oxide is an ultrafine particle, it may not be effective to uniformly coat the zinc oxide particle surface, and precipitation and separation are likely to occur. There is a tendency to become. When the pigment dispersant exceeds 50 phr, the light resistance, heat resistance, moist heat resistance and the like of the coating film and the pressure-sensitive adhesive may be deteriorated.

  In the method for producing a zinc oxide dispersion paste of the present invention, for mixing and preliminary dispersion of zinc oxide, a pigment dispersant, and a dispersion medium, for example, a method of slowly mixing and stirring the entire dispersion with a three-one motor is recommended. A large stirring blade such as a Max blend blade or a paddle is desirable. This may also use a planetary mixer. It is sufficient for the preliminary dispersion to be a uniform dispersion as a whole.

  When using a stirrer or disperser with a strong shearing force such as a homogenizer or disperser for pre-dispersion, a lump with a strong cohesive force tends to be formed (hereinafter also referred to as agglomerate). On the contrary, there is a case where the purpose cannot be achieved because it becomes impossible to unravel.

  In the preliminary dispersion, a method in which a pigment dispersant is dissolved in a dispersion medium and zinc oxide is added little by little while stirring is recommended.

  The dispersion produced by the preliminary dispersion is passed through a bead mill to carry out the main dispersion.

  Examples of the bead mill include Dino mill (Shinmaru Enterprises' pigment disperser), Ultra Apex mill (Koto Kogyo's pigment disperser), Spike mill (Inoue's pigment disperser), Advantis (Buhler's Pigment dispersers), star mills (Ashizawa Finetech pigment dispersers), sand mills and the like.

  In the method for producing a zinc oxide-dispersed paste of the present invention, a pigment disperser capable of using finer particle media such as ultraapex mill, advantis, star mill and the like, for example, 1 mm or less in order to produce a finer and more stable dispersion. Is recommended as a suitable disperser.

  In the pigment dispersion in the bead mill, the zinc oxide concentration is preferably 10 to 50% by weight, more preferably 20 to 45% by weight, and further preferably 25 to 40% by weight. When the zinc oxide concentration is less than 10% by weight, not only the zinc oxide dispersion efficiency is poor, but also it may be difficult to increase the zinc oxide concentration in the film, and sufficient UV absorption and conductivity are obtained. It may not be possible. When zinc oxide exceeds 50% by weight, the viscosity during pigment dispersion tends to be high, and thixotropic properties tend to be obtained, and pigment dispersion tends to be insufficient.

The method for producing a zinc oxide-dispersed paste of the present invention is a method for producing a zinc oxide-dispersed paste that is dispersed by a bead mill, and the dispersion medium is toluene, ethyl acetate, butyl acetate , 1- hexyl-3-methylimidazolium hexafluoro and at least one dispersing medium selected Hosufe bets or al,
When the shear rate is ¹ to 10 s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersed paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 50)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; A method for producing a zinc oxide dispersion paste that is at least one kind,
When the shear rate is 10 to 10 ² s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersed paste having a zinc oxide concentration of 25 to 35% by weight at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 30)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; This is a method for producing at least one zinc oxide dispersion paste.

  In the method for producing a zinc oxide dispersion paste of the present invention, preferably, zinc oxide, a dispersion medium, and a pigment dispersant are mixed and predispersed, and then pigment dispersion is performed by a bead mill.

  In the method for producing a zinc oxide-dispersed paste of the present invention, dispersion conditions, for example, media diameter of media (1 mm, 0.5 mm, 0.3 mm, 0.05 mm, 0.03 mm, etc.), filling rate of media (large, small) Etc.), pigment flow rate (fast, slow, etc.), pigment dispersion temperature (forced cooling, normal cooling, heating, etc.), pigment disperser peripheral speed (fast, slow, etc.), pigment dispersion device, media Adjusting the material (glass, ceramic, metal, etc.), pigment disperser dispersion chamber (glass, ceramic, metal, etc.), pigment concentration (high, low, etc.), pigment dispersant concentration (high, low, etc.) decide.

  In the method for producing a zinc oxide-dispersed paste of the present invention, the following conditions are recommended in order to improve the storage stability of the zinc oxide-dispersed paste and improve the performance when producing paints and adhesives.

  In order to improve dispersibility and to make fine particles, the smaller the particle diameter of the media, the more desirable and 1 mm or less. Moreover, the material made from a ceramic is recommended also in the meaning which avoids mixing of a foreign material, and the thing made from a zirconia is recommended especially. It is recommended that the media filling ratio is preferably 60% or more, more preferably 70% or more, and further preferably 80% or more. When the media filling rate is less than 60%, a sufficient dispersion state cannot be obtained, and separation and sedimentation tend to occur.

  The dispersion chamber of the disperser is also preferably made of ceramics in order to avoid contamination by foreign substances, and in particular, it is recommended that it is made of zirconia.

  The flow rate during pigment dispersion is preferably 200 ml / min or more, more preferably 500 ml / min or more, and still more preferably 800 ml / min in order to increase the number of collisions between zinc oxide particles and media and produce a more stable dispersion. The above is desirable. When the flow rate is less than 200 ml / min, the dispersion paste tends to cause flocculation and agglomeration, and storage stability and pot life may be deteriorated. It is desirable and recommended that the flow rate be approximately 1/3 or more capacity / min of the inner volume of the dispersion vessel, and more preferably 1/2 or more of the inner volume of the dispersion vessel.

  The temperature at which the pigment is dispersed need not be specified, but it is desirable that the temperature is not higher than the boiling point in consideration of the boiling point of the dispersion medium. In general, if the ability of the pigment disperser permits, it is desirable to carry out at 40 ° C. or less as much as possible.

  The pigment dispersant is preferably blended in an amount of 2 to 50 phr, more preferably 5 to 50 phr, and still more preferably 8 to 40 phr with respect to zinc oxide. When the blending amount of the pigment dispersant is less than 2 phr, since the zinc oxide is an ultrafine particle, it may not be effective to uniformly coat the zinc oxide particle surface, and precipitation and separation are likely to occur. There is a tendency to become. When the pigment dispersant exceeds 50 phr, the light resistance, heat resistance, moist heat resistance and the like of the coating film and the pressure-sensitive adhesive may be deteriorated.

In the method for producing a zinc oxide-dispersed paste of the present invention, the viscosity of the zinc oxide-dispersed paste is measured under the following conditions using a “VAR-type Visco Analyzer” (Rheology measuring device of Jusco International Co., Ltd.).
[Viscosity measurement conditions]
・ Measurement temperature 25 ℃
2. Shear rate table Shear rate 1.000E + 0 to 1.000E + 4 s ⁻¹ , delay time 2.000E + 0 s, integrated steady state equilibrium value + −0.010
3. Regulator strength 100.0%
4). Measure normal force
5). Measurement test geometry Cone plate
Corn: C 40 1 (40 mm 1 ° C. Plate)
6). Measurement interval 2,000E + 0 s
In the method for producing a zinc oxide dispersed paste of the present invention, when the shear rate is ¹ to 10 s ⁻¹ , the viscosity (mPa · s) of the dispersed paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 50)
The viscosity of the dispersion paste is preferably
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 25)
More preferably,
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 20)
It is desirable that

  When the viscosity of the dispersion paste exceeds (dispersion medium viscosity × 50) mPa · s (25 ° C.), the dispersion paste has strong flocculation regardless of the average particle diameter of the dispersed zinc oxide. Therefore, precipitation, separation, and gelation are likely to occur when a diluent solvent or a curing agent is blended. In particular, when a curing agent such as urethane or epoxy resin is blended, the pot life is drastically shortened.

In the method for producing a zinc oxide dispersed paste of the present invention, when the shear rate is 10 to 10 ² s ⁻¹ , the viscosity (mPa · s) of the dispersed paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 30)
And preferably
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 20)
More preferably, (dispersion medium viscosity) ≦ (dispersion paste viscosity) ≦ (dispersion medium viscosity × 12.5)
It is desirable that

  When the viscosity of the dispersion paste exceeds (dispersion medium viscosity × 30) mPa · s (25 ° C.), the dispersion paste exhibits strong flocculation and agglomerate regardless of the particle diameter of the dispersed zinc oxide, It tends to cause precipitation and separation.

  In the method for producing a zinc oxide-dispersed paste of the present invention, the viscosity of the zinc oxide-dispersed paste is required to strictly satisfy the above conditions, but the dispersed zinc oxide particle size is not necessarily close to the average primary particle size. It is not necessary to make fine particles. Even if the dispersion condition is selected or the pigment dispersion is performed until the particle diameter of the dispersion is close to the average primary particle diameter over time, if the above conditions are not satisfied, the stability of the dispersion paste and various Function is not obtained.

  On the other hand, as a matter of course, when a dispersion close to the primary particle size can be produced by dispersion and the above viscosity condition is satisfied, further excellent dispersion stability and performance can be expected.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, unless there is particular notice, a composition ratio shall show a weight ratio.

  Moreover, in order to make the effect easy to understand, in the following examples and comparative examples, the zinc oxide concentration was all set to 30% by weight.

  The particle size is “concentrated particle size analyzer FPAR-1000” (Otsuka Electronics Co., Ltd. Laser Light Scattering Particle Size Distribution Measuring Device) (hereinafter also referred to as particle size device), converted to scattering intensity distribution at 25 ° C. The value obtained for the average particle diameter was adopted.

  As described above, the rheology measurement was performed under the conditions described above using a “VAR-type Bisco Analyzer” (a rheology measuring apparatus manufactured by Jusco International Co., Ltd.).

Example 1
In a 2 L stainless steel container, 700 g of ethyl acetate (viscosity 0.43 mPa · s / 25 ° C.) as a dispersion solvent, “Disparon DA-7300” (Enomoto Kasei Co., Ltd.), amide amine salt of high molecular weight polyester acid as a pigment dispersant 80% of active ingredient) was charged and stirred until uniform using a three-one motor.

  To this, 300 g of “ZINCOX SUPER F-2” (Haxitec Co., Ltd. zinc oxide, average primary particle diameter 70 nm) (hereinafter also referred to as F-2) was added little by little, and the zinc oxide was dispersed by stirring for 30 minutes. A slurry was produced.

  The slurry was dispersed in zinc oxide using a “LABSTAR / MINI CER” (Ashizawa Finetech Co., Ltd. pigment disperser) (hereinafter also referred to as mini) (zinc oxide concentration is 30% by weight). .

Dispersion conditions were vessel material ZrO ₂ , rotor ZrO ₂ , media ZrO ₂ , media diameter 0.1 mm, media filling rate 85%, peripheral speed 10 m / sec, and slurry was supplied at 300 ml / min using a diaphragm pump. The temperature of the slurry during dispersion was adjusted (cooled) to 20 to 30 ° C.

After dispersion for 2 hours, the average particle size was 95 nm. In addition, as a result of rheology measurement,
The minimum value of the viscosity at a minimum 1.98mPa · s viscosity, maximum 5.49mPa · s, shear rate 10 to 10 ² s ^-1 at a shear rate 1～10S ^-1 1 It was 0.44 mPa · s, and the maximum value was 1.80 mPa · s.

  The manufactured zinc oxide dispersion paste was placed in a 500 ml mayonnaise bottle and allowed to stand at 23 ° C. for 1 month, but it was stable without causing separation or precipitation.

[Evaluation of paint]
Acrylic resin (hereinafter also referred to as AC) composed of methyl methacrylate / n-butyl methacrylate / n-butyl acrylate / 2-hydroxyethyl methacrylate (= 50/20/25/5) dissolved in ethyl acetate (solid content) 50% concentration, weight average molecular weight of acrylic 28000) and zinc oxide dispersion paste were mixed so that the solid content conversion pigment concentration (hereinafter also referred to as PWC) was 50%, and 2-ethylhexanoic acid was further added to the acrylic solution in an amount of 0.1%. 5 phr, isopropyl alcohol is mixed with 5 phr of acrylic, and “K-KAT 348” (curing catalyst of Enomoto Kasei Co., Ltd.) is mixed with 2 phr of acrylic, and the mixture is stirred with a stirrer for 30 minutes. Furthermore, “Mazerustar” (Kurabo Co., Ltd. stirring and defoaming apparatus) was used, and stirring and defoaming were performed for 20 minutes. "Sumijoule N-3300" (isocyanate compound of Sumitomo Bayer Urethane Co., Ltd.) (curing agent) so that the equivalent ratio of OH group of acrylic to NCO group of curing agent is 1: 2 in this paint (main agent) And a urethane curable paint containing zinc oxide.

  The urethane curable paint containing zinc oxide was stirred and defoamed with "Mazelstar" for 30 minutes, and then put into a 100 ml glass bottle and stoppered. It left still in a 25 degreeC thermostat, and the coating-material state was observed. Even after 12 hours, the appearance and fluidity of the paint did not change, and the zinc oxide-containing urethane curable paint was stable even after the curing agent was blended.

  A urethane curable paint containing zinc oxide was applied to a transparent PET film so as to have a dry film thickness of 3 μm, and baked and dried at 130 ° C. for 2 minutes. This was immersed in methyl ethyl ketone for 1 minute, but the coating film did not change, and it was observed that the crosslinking reaction had progressed sufficiently.

  As a result of measuring the light transmittance of 300 to 500 nm with a spectrophotometer using the coated PET film as a reference, the light transmittance of 300 to 380 nm is 10% or less, and the light transmittance of 400 nm to 500 nm is 80% or more. Met. It was found that the manufactured paint was excellent in ultraviolet blocking performance and visible light transmission performance.

Example 2
Into a 3 L stainless steel container, 1400 g of ethyl acetate (viscosity 0.43 mPa · s / 25 ° C.) as a dispersion solvent and 120 g of “Disparon DA-7300” as a pigment dispersant are stirred until uniform using a three-one motor. did.

  To this, “Pazet CK” (Huxitec Co., Ltd. conductive zinc oxide (aluminum dope), average primary particle diameter 20 nm) (hereinafter also referred to as “CK”) 600 g was added little by little, and stirred for 30 minutes. A dispersed slurry was produced.

  This slurry was dispersed with zinc oxide using “Starmill LMZ-2” (Ashizawa Finetech Co., Ltd. pigment disperser) (hereinafter also referred to as LMZ) (zinc oxide concentration is 30% by weight). .

Dispersion conditions, Bessel material Arujiru, rotor ZrO _2, Mejia ZrO _2, Mejia diameter 0.1 mm, Mejia filling rate of 85%, peripheral speed 10 m / sec, the slurry was supplied at 1.5 L / min using a diaphragm pump. The temperature of the slurry during dispersion was adjusted (cooled) to 20 to 30 ° C.

After dispersion for 2 hours, the average particle size was 30 nm. As a result of rheological measurements, when the minimum value is 2.28mPa · s viscosity at a shear rate 1～10S ^-1, the maximum value is 20.5 MPa · s, is shear rate of 10 to 10 ² s ^-1 The viscosity had a minimum value of 1.12 mPa · s and a maximum value of 1.78 mPa · s.

  The manufactured zinc oxide dispersion paste was placed in a 500 ml mayonnaise bottle and allowed to stand at 23 ° C. for 1 month, but it was stable without causing separation or precipitation.

[Evaluation of conductive adhesive]
Acrylic resin (hereinafter also referred to as AC2) composed of 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate (= 95/5) dissolved in toluene / ethyl acetate (= 60/40) (solid content concentration 40%, acrylic Number average molecular weight 192000) and zinc oxide dispersion paste were mixed so that PWC was 50%, and “Mazerustar” was used for 30 minutes stirring and defoaming. “Sumidule N-3300” (curing agent) is blended with this pressure-sensitive adhesive (main agent) so that the equivalent ratio of acrylic OH group to NCO group of the curing agent is 1: 1, and a urethane-cured urethane compound containing zinc oxide. A conductive adhesive (hereinafter also referred to as adhesive 1) was produced.

  The pressure-sensitive adhesive 1 was stirred and defoamed with “Mazerustar” for 30 minutes, and then put into a 100 ml glass bottle and stoppered. It left still in a 25 degreeC thermostat, and the coating-material state was observed. Even after 24 hours, the paint appearance and fluidity did not change, and the adhesive 1 was stable.

  Adhesive 1 was applied to a transparent PET film so that the dry film thickness was 25 μm, and baked and dried at 100 ° C. for 2 minutes.

  After this adhesive film was cured at 23 ° C. for 1 week and then applied to a glass plate with a load of 2 kg, it showed good adhesiveness and removability. Moreover, as a result of measuring the light transmittance of 300-500 nm with this coated film spectrophotometer using the coated PET film as a reference, the light transmittance of 300-380 nm is 10% or less, and the light transmittance of 400 nm-500 nm. The rate was 80% or more. It was found that the produced pressure-sensitive adhesive 1 was excellent in ultraviolet blocking performance and visible light transmission performance.

Furthermore, when the electric resistance of this adhesive film (adhesive layer) was measured, it was 2.8 × 10 ⁷ Ω / □. It was found to be sufficient as an antistatic adhesive.

Example 3
Three-one stainless steel container was charged with 1400 g of 1-hexyl-3-methylimidazolium hexafluorophosphate (ionic liquid, viscosity 358 mPa · s) as a dispersion solvent and 120 g of “Disparon DA-7300” as a pigment dispersant. Was stirred until homogeneous.

  To this, 600 g of “CK” was added little by little, and stirred for 30 minutes to produce a slurry in which zinc oxide was dispersed.

  This slurry was dispersed with zinc oxide using “LMZ” (zinc oxide concentration was 30 wt%).

Dispersion conditions, Bessel material Arujiru, rotor ZrO _2, Mejia ZrO _2, Mejia diameter 0.1 mm, Mejia filling rate of 85%, peripheral speed 10 m / sec, the slurry was supplied at 1.5 L / min using a diaphragm pump. The temperature of the slurry during dispersion was adjusted (cooled) to 20 to 30 ° C.

After dispersion for 2 hours, the average particle size was 30 nm. The minimum viscosity when the results of rheological measurements, minimum 2864mPa · s viscosity at a shear rate 1～10S ^-1, maximum 4296mPa · s, shear rate 10 to 10 ² s ^-1 The value was 1790 mPa · s, and the maximum value was 2864 mPa · s.

  The manufactured zinc oxide dispersion paste was placed in a 500 ml mayonnaise bottle and allowed to stand at 23 ° C. for 1 month, but it was stable without causing separation or precipitation.

[Evaluation of conductive adhesive]
Acrylic resin (hereinafter also referred to as AC3) composed of EHA / 3-ethyl-3-oxetanylmethyl methacrylate (= 98/2) dissolved in 3-ethyl-3-hydroxymethyloxetane (polymer concentration 85%, number average molecular weight 82000) 100 g, zinc oxide dispersion paste 50 g, triallylsulfonium hexafluorophosphate salt (photocation polymerization initiator) 4 g were mixed, stirred for 30 minutes with “Mazerustar”, and defoamed to produce a conductive gel-like pressure-sensitive adhesive. .

  This was applied to a PET film so that the film thickness was 250 μm, and then UV-irradiated to produce an adhesive film.

After sticking the adhesive film on the glass plate, the impact resistance was evaluated at 300 g × 10 cm using a DuPont impact tester, but the glass plate was not damaged and was excellent in impact resistance absorption. In addition, the electric resistance of the adhesive layer was 2.3 × 10 ¹ Ω · cm, indicating good conductivity.

Example 4
In Example 1, except that the zinc oxide was changed to “ZnO-350” (Zinc oxide of Sumitomo Osaka Cement Co., Ltd., average primary particle diameter 20 nm) (hereinafter also referred to as SOC), the zinc oxide dispersion was performed in the same manner as in Example 1. A paste was produced.

After dispersion for 2 hours, the average particle size was 40 nm. As a result of rheological measurements, when the minimum value is 0.810mPa · s viscosity at a shear rate 1～10S ^-1, the maximum value is 2.45 MPa · s, is shear rate of 10 to 10 ² s ^-1 The minimum value of the viscosity was T2 = 1.05 mPa · s, and the maximum value was 1.29 mPa · s.

  The manufactured zinc oxide dispersion paste was placed in a 500 ml mayonnaise bottle and allowed to stand at 23 ° C. for 1 month, but it was stable without causing separation or precipitation.

  This dispersion paste was diluted with EAc so that the zinc oxide concentration became 5%, and it was put in a 100 ml glass bottle and the appearance was observed. As a result, it was a yellowish clear liquid. It was observed that the dispersibility was excellent.

[Evaluation of adhesive]
AC2 and zinc oxide dispersion paste were mixed so that the PWC was 50%, and “Mazerustar” was used for 30 minutes stirring and defoaming. “Sumidule N-3300” (curing agent) is blended with this pressure-sensitive adhesive (main agent) so that the equivalent ratio of acrylic OH group to NCO group of the curing agent is 1: 1, and a urethane-cured urethane compound containing zinc oxide. An adhesive (hereinafter also referred to as adhesive 2) was produced.

  The pressure-sensitive adhesive 2 was stirred and degassed with “Mazerustar” for 30 minutes, and then put into a 100 ml glass bottle and stoppered. It left still in a 25 degreeC thermostat, and the coating-material state was observed. Even after 24 hours, the paint appearance and fluidity did not change, and the adhesive 2 was stable.

  Adhesive 2 was applied to a transparent PET film so that the dry film thickness was 25 μm, and baked and dried at 100 ° C. for 2 minutes.

  After this adhesive film was cured at 23 ° C. for 1 week and then applied to a glass plate with a load of 2 kg, it showed good adhesiveness and removability. Moreover, as a result of measuring the light transmittance of 300-500 nm with this coated film spectrophotometer using the coated PET film as a reference, the light transmittance of 300-380 nm is 5% or less, and the light transmittance of 400 nm-500 nm. The rate was 85% or more. It was found that the produced pressure-sensitive adhesive 2 was excellent in ultraviolet blocking performance, visible light transmission performance, and transparency.

Comparative Example 1
In a 5 L stainless steel container, 2450 g of ethyl acetate (viscosity 0.43 mPa · s / 25 ° C.) as a dispersion solvent and 210 g of “Disparon DA-7300” as a pigment dispersant are charged and stirred using a three-one motor until uniform. To do.

  To this, 1050 g of “SOC” (zinc oxide, “ZnO-350”) is added little by little, and stirred for 30 minutes to produce a slurry in which zinc oxide is dispersed.

  This slurry was dispersed with zinc oxide using a “Dinomill” (Shinmaru Enterprises Co., Ltd. pigment disperser) (zinc oxide concentration is 30 wt%).

Dispersion conditions were vessel material ZrO ₂ , rotor ZrO ₂ , media ZrO ₂ , media diameter 0.3 mm, media rate 85%, peripheral speed 10 m / sec, and slurry was supplied at 150 ml / min using a diaphragm pump. The temperature of the slurry during dispersion was adjusted (cooled) to 20 to 30 ° C.

After 10 passes of dispersion while circulating the dispersion, the average particle size was 150 nm. As a result of rheological measurements, when the minimum value is 1.89mPa · s viscosity at a shear rate 1～10S ^-1, maximum 23.7mPa · s, is shear rate of 10 to 10 ² s ^-1 The viscosity had a minimum value of 0.998 mPa · s and a maximum value of 1.45 mPa · s.

  When the produced zinc oxide dispersion paste was put into a 500 ml mayonnaise bottle and allowed to stand at 23 ° C., precipitation was confirmed on the third day. The dispersion was unstable.

[Evaluation of paint]
AC and zinc oxide dispersion paste are mixed so that the PWC is 50%. Further, 2-ethylhexanoic acid is mixed with 0.5 phr of acrylic, isopropyl alcohol is mixed with 5 phr of acrylic, and “K-KAT 348” is mixed with 2 phr of acrylic. And stir with a stirrer for 30 minutes. Furthermore, “Mazerustar” was used, and stirring and defoaming were performed for 20 minutes. This paint (main agent) is blended with "Sumidur N-3300" (curing agent) so that the equivalent ratio of acrylic OH groups to NCO groups of the curing agent is 1: 2, and a urethane curable paint containing zinc oxide. Manufactured.

  The urethane curable paint containing zinc oxide was stirred and defoamed with "Mazelstar" for 30 minutes, and then put into a 100 ml glass bottle and stoppered. It left still in a 25 degreeC thermostat, and the coating-material state was observed. After about 2 hours, the coating became gelled and unstable.

Comparative Example 2
In a 2 L stainless steel container, 700 g of ethyl acetate (viscosity 0.43 mPa · s / 25 ° C.) as a dispersion solvent and 36 g of “Disparon DA-7300” as a pigment dispersant are charged and stirred using a three-one motor until uniform. To do.

  To this, 300 g of “Pazet GK-2” (gallium-doped conductive zinc oxide of Hakusitec Co., Ltd., average primary particle size 30 nm) (hereinafter also referred to as GK) was added little by little, and the mixture was stirred for 30 minutes. A dispersed slurry was produced.

  This slurry was dispersed with zinc oxide using “LABSTAR / MINI CER” (zinc oxide concentration is 30% by weight).

Dispersion conditions were vessel material ZrO ₂ , rotor ZrO ₂ , media ZrO ₂ , media diameter 0.1 mm, media filling rate 85%, peripheral speed 10 m / sec, and slurry was supplied at 200 ml / min using a diaphragm pump. The temperature of the slurry during dispersion was adjusted (cooled) to 20 to 30 ° C.

After dispersion for 2 hours, the average particle size was 45 nm. The viscosity when the results of rheological measurements, minimum 34.2mPa · s viscosity at a shear rate 1～10S ^-1, the maximum value is 149mPa · s, shear rate 10 to 10 ² s ^-1 The minimum value was 6.88 mPa · s, and the maximum value was 22.8 mPa · s.

  When the produced zinc oxide dispersion paste was placed in a 500 ml mayonnaise bottle and allowed to stand at 23 ° C., precipitation occurred on the first day and the dispersion was unstable.

Comparative Example 3
In Comparative Example 1, instead of “SOC”, zinc oxide “NANOFINE s-50” (surface-treated zinc oxide of Sakai Chemical Co., Ltd., d = 20 nm) was used, and zinc oxide was dispersed under the same conditions. went.

After 10 passes of dispersion while circulating the dispersion, the average particle size was 98 nm. As a result of rheological measurements, when the minimum value is 3.06mPa · s viscosity at a shear rate 1～10S ^-1, maximum 35.0mPa · s, is shear rate of 10 to 10 ² s ^-1 The minimum value of the viscosity was 1.97 mPa · s, and the maximum value was 2.26 mPa · s.

  When the produced zinc oxide dispersion paste was put into a 500 ml mayonnaise bottle and allowed to stand at 23 ° C., precipitation was confirmed on the fifth day. The dispersion was unstable.

Claims (5)

A method for producing a zinc oxide dispersion paste dispersed in a bead mill, the dispersion medium, toluene, ethyl acetate, butyl acetate, 1 - hexyl-3-methylimidazolium hexafluorophosphate or selected the at least one When the shear rate is ¹ to 10 s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersion paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 50)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; A method for producing at least one zinc oxide dispersion paste. A method for producing a zinc oxide dispersion paste dispersed in a bead mill, the dispersion medium, toluene, ethyl acetate, butyl acetate, 1 - hexyl-3-methylimidazolium hexafluorophosphate or selected the at least one When the shear rate is 10 to 10 ² s ⁻¹ , the viscosity (mPa · s) of the zinc oxide dispersion paste having a zinc oxide concentration of 25 to 35 wt% at 25 ° C.
(Viscosity of dispersion medium) ≦ (Viscosity of dispersion paste) ≦ (Viscosity of dispersion medium × 30)
A polyester containing a dispersion medium and a pigment dispersant, wherein the pigment dispersant has a nonionic surfactant, an anionic surfactant, an amino group, an amide group, and a carboxylic acid group at the same time; A method for producing at least one zinc oxide dispersion paste. The method for producing a zinc oxide-dispersed paste according to claim 1 or 2, wherein the average primary particle diameter of zinc oxide is 0.5 to 200 nm. The method for producing a zinc oxide-dispersed paste according to claim 1, wherein the zinc oxide is conductive zinc oxide doped with aluminum. The method for producing a zinc oxide-dispersed paste according to claim 1, wherein the zinc oxide is a conductive zinc oxide doped with gallium.