JP7128057B2 - Compounding agent for paint - Google Patents

Description

The present invention relates to coating formulations comprising surface-treated inorganic oxide particles.

Inorganic oxide particles such as silica have conventionally been blended into paints as matting agents for the purpose of reducing the glossiness of the coating film surface. This matting agent forms fine irregularities on the coating film surface, thereby lowering the gloss value.

By the way, the inorganic oxide particles as described above are usually used after being surface-treated with an organic material such as polyolefin wax in order to improve dispersibility in paints and resins (see, for example, Patent Document 1). Waxes used as surface treatment agents for inorganic oxide particles are solid at room temperature, but when waxes with a low melting point are used, the problem of bleeding out occurs. Therefore, it is desired to use a polyolefin wax with a high melting point, such as a polypropylene wax.

When such a high-melting polypropylene wax is used as a surface treatment agent, it is generally melt-kneaded with inorganic oxide particles. There is an inconvenience that

The use of organic solvents is conceivable as a means of resolving such inconveniences, but organic solvents pose problems of disposal and the environment. still not resolved.

Therefore, it is also known to use polypropylene wax in the form of an emulsion for surface treatment of inorganic oxide particles at a relatively low temperature (Patent Document 2).

The surface treatment of inorganic oxide particles using an aqueous polypropylene emulsion has the advantage that it can be carried out at a relatively low temperature and that there is no need to worry about disposal or environmental problems because an organic solvent is not used. is doing.

However, according to the research of the present inventors, when surface treatment is performed using an aqueous polypropylene emulsion, there is a tendency, although slight, to cause yellowing, which may impair the aesthetic appearance of the coating film. The actual situation is that the practicality as a compounding agent is hindered.

JP-A-2000-136265 JP-A-11-60231

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a paint formulation which effectively suppresses yellowing in spite of using an aqueous emulsion of polypropylene having a high melting point as a surface treatment agent.

The present inventors have conducted many experiments and studied yellowing that occurs when inorganic oxide particles are surface-treated using a polypropylene wax emulsion. The present inventors have obtained knowledge that it is derived from conditions, and have completed the present invention based on this knowledge.

According to the present invention, a paint compounding agent comprising inorganic oxide particles surface-treated with an aqueous emulsion of polypropylene wax having a melting point of 140° C. or higher,
The polypropylene wax is contained in an amount of 1 to 15 parts by mass per 100 parts by mass of the inorganic oxide particles,
A paint formulation is provided which is characterized by a Hunter brightness of 90% or greater.

In the paint compounding agent of the present invention,
(1) the inorganic oxide particles have a bulk density of 0.1 to 1.5 g/cm ³ ;
(2) the inorganic oxide particles are silica;
(3) Carbonyl group calculated by FT-IR measurement (>C=O, Wavenumbers 1701 cm ^-1 ) (i), carboxylate in carboxylate (-COO ^- , Wavenumbers 1558 cm ^-1 )... (ii), water (H ₂ O, Wavenumbers 1630 cm −1 ) (iii), polypropylene (PP, Wavenumbers 1461 cm ⁻¹ ) (iv) peak intensity ratio ( ^ixii /iii/ iv) is less than or equal to 0.25;
(4) the average particle size is adjusted to 1 to 50 μm;
(5) The average particle size used as a compounding agent for curable paint is adjusted to 1 to 50 μm,
is preferred.

The paint compounding agent of the present invention is surface-treated with polypropylene wax, so that when it is incorporated in the paint, it is uniformly dispersed in the resin for forming the coating film, and the inorganic oxide fine particles provide a matting effect. The first feature is that the polypropylene wax has a melting point of 140° C. or higher. That is, when the melting point of this polypropylene wax is low, or when the surface treatment is performed with polyethylene wax instead of polypropylene, bleeding from the coating film becomes remarkable, and the decorativeness of the coating film deteriorates due to whitening or the like. It may be damaged. In particular, when blended in a UV curable paint, bleeding is conspicuous when the temperature rises during the formation of a coating film by light irradiation.
However, in the present invention, as described above, the problem of bleeding is effectively solved because the surface is treated using a polypropylene wax having a high melting point.

The second feature of the paint compounding agent of the present invention is that it is surface-treated using the aqueous emulsion of the high-melting point polypropylene wax.
That is, since it is a surface treatment using an aqueous emulsion, there is no need for complicated equipment such as melt-kneading, and there is no need for exhaust equipment for solvent removal, etc., and there is no adverse effect on the environment. Moreover, it does not increase the manufacturing cost.

Furthermore, in the paint compounding agent of the present invention, the content of the high melting point polypropylene wax (that is, the surface treatment amount) is 1 to 15 parts by mass, preferably 1 to 9 parts by mass, per 100 parts by mass of the inorganic oxide particles. The third feature is that it is adjusted to a certain range. That is, the amount of surface treatment with polyolefin wax or the like generally exceeds 10 parts by mass per 100 parts by mass of inorganic oxide particles. . As a result, by adjusting the surface treatment conditions (temperature and treatment time) using the emulsion, yellowing is effectively avoided, and the Hunter whiteness is 90% or more, preferably 93% or more, particularly preferably 96%. % or more, and an extremely high degree of whiteness is ensured.

That is, in the paint compounding agent of the present invention, yellowing is effectively suppressed and excellent whiteness is obtained in spite of the fact that the surface is treated with an aqueous emulsion. Therefore, the paint compounding agent of the present invention can be produced at a low cost and effectively avoids deterioration of the appearance of the coating film due to yellowing and bleeding. , is industrially extremely useful.

The relationship between the whiteness of the paint compounding agents obtained in Experimental Examples and the peak intensity ratio including carbonyl groups (>C=O) calculated by FT-IR measurement. Peak intensity observed in FT-IR measurement of the paint formulation obtained in Comparative Example 1. Viscosity of the UV curable paint compounded with the paint compounding agent (Example 1) used in the paint experiment and UV curable paint compounded with silica (inorganic oxide particles (A)) were measured with a rotational viscometer. The figure which shows a viscosity.

The paint compounding agent of the present invention has a particle structure in which the surfaces of the inorganic oxide particles are covered with the polypropylene wax used as the surface treatment agent.

<Inorganic oxide particles>
The inorganic oxide particles to be surface-treated are not particularly limited, and may be silica, alumina, titanium oxide, magnesium oxide, calcium oxide, or a mixture of two or more of these inorganic oxides, or a composite of two or more of these inorganic oxides. compound inorganic oxides (e.g., aluminosilicates, titanosilicates), etc., which are known per se, but are particularly chemically and thermally stable and are preferably used as compounding agents for paints. , alumina, titanium oxide and the like are preferred, and silica is most preferred.

In addition, the above-mentioned inorganic oxide particles may contain a large amount of impurities such as various inorganic salts. It becomes easy to produce dispersion|variation in the characteristic as a compounding agent etc. for. Therefore, it is desirable that such impurities be as small as possible, and for inorganic oxide particles containing a large amount of impurities, it is preferable to reduce the impurity content by, for example, elutriation or washing with water.
For example, high-purity inorganic oxide particles have high electrical resistance, and those with a high impurity content have low electrical resistance. In particular, it is preferable to reduce the impurity content to 40 kΩ·cm or more.

In the present invention, the inorganic oxide particles preferably have a bulk density in the range of 0.1 to 1.5 g/cm ³ , particularly 0.1 to 0.7 g/cm ³ . That is, bulky materials with a low bulk density may collapse particles when blended in paints, resins, etc., and may cause significant thickening, fluctuations in refractive index, etc., but the bulk density is within the above range. By using dense particles, the above problems can be effectively prevented. In addition, if the bulk density becomes larger than necessary, for example, when a paint film is formed by blending it with a paint or the like, the paint film is more likely to be scratched by rubbing. should be in range.

From the above point of view, in the present invention, the inorganic oxide most preferably used as the inorganic oxide to be surface-treated is so-called gel silica or precipitation silica.
Such gel-process silica has, for example, a dense structure corresponding to the core of the double structure amorphous silica particles of Patent Document 2 described above, and is obtained by mixing an alkali silicate aqueous solution and a mineral acid aqueous solution at a pH of 2 to 10. Obtained by neutralizing under conditions. A so-called sedimentation method is also known for other silica, and amorphous silica obtained by such a method is also suitably used as inorganic oxide particles to be surface-treated.

<Polypropylene wax>
In the present invention, the polypropylene wax used as the surface treatment agent and covering the surfaces of the inorganic oxide particles has a melting point of 140° C. or higher, particularly 160° C. or higher. This melting point is a peak top value measured by so-called differential thermal analysis (DSC). When blended, bleeding tends to occur when subjected to heat history due to heating during coating or film formation, for example, the slipperiness is enhanced, the coating film properties and film physical properties are impaired, and the use is reduced. It is unsuitable for the present invention because it is too restrictive.

Moreover, the surface treatment with this wax is carried out using the wax in the form of an emulsion, as will be described later. Therefore, the polypropylene forming this wax is copolymerized with an unsaturated carboxylic acid having an ethylenically unsaturated bond, such as maleic anhydride or (meth)acrylic acid, in order to improve dispersibility in water. That is, by introducing such a compound having a polar group as a copolymerization component, the affinity for water is enhanced, and an emulsion can be prepared.

In the case of using ordinary polypropylene wax into which no polar group is introduced as described above, for example, surface treatment is performed using melt-kneading or an organic solvent. High-temperature heating and processing facilities for disposal of organic solvents are required, which leads to an increase in cost and makes it impossible to achieve the object of the present invention.

In the present invention, the polypropylene wax described above is present on the surfaces of the inorganic oxide particles in an amount of 1 to 15 parts by weight, particularly 1 to 9 parts by weight, per 100 parts by weight of the inorganic oxide particles. If this amount (amount of wax impregnated) is less than the above range, the particles tend to agglomerate, making it difficult to uniformly disperse the wax in the paint or resin, or when the wax is dispersed in the paint or resin. As a result, the blending amount is limited, and it becomes difficult to impart desired properties to paints and resins. Also, if the amount is set higher than the above range, yellowing will occur due to the surface treatment using the aqueous emulsion described later.

<Characteristics of surface-treated inorganic oxide particles>
The surface-treated inorganic oxide particles used as the paint compounding agent of the present invention are obtained by attaching the copolymer-modified polypropylene wax to the surface of the inorganic oxide particles in the above amount for forming an emulsion. In addition, it has a Hunter whiteness of 90% or more, preferably 93% or more, and particularly preferably 96% or more, which is an extremely high degree of whiteness.

That is, according to the studies of the present inventors, it has been found that yellowing occurs when surface treatment is performed using an aqueous emulsion of polypropylene wax (hereinafter sometimes referred to as emulsion method surface treatment). In particular, this yellowing is relatively slight when surface-treating a small amount of inorganic oxide particles, as typified by laboratory experiments, and does not appear to be a problem with the naked eye. It appears significantly when surface treatment is performed on a large amount of inorganic oxide particles in . That is, in the emulsion method surface treatment, it is necessary to use equipment (drying equipment for removing moisture) that is completely different from surface treatment using an organic solvent or surface treatment by melt-kneading, which has been conventionally adopted. Therefore, even though small-scale production was carried out in the laboratory, it was hardly carried out industrially, so this kind of yellowing was not regarded as a problem. It seems that it was not considered.

Although the reason why the above-mentioned yellowing occurs has not been clearly elucidated, the present inventors presume that the oxidative deterioration of polypropylene is the reason for the yellowing. That is, polypropylene contains tertiary carbon atoms that are easily oxidized, and at the same time, copolymer units of unsaturated carboxylic acids such as maleic anhydride are introduced into the molecule, so that it contains easily oxidizable unsaturated groups. there is Therefore, it is considered that the yellowing is caused by oxidation due to heating or the like during surface treatment to generate low-molecular-weight components such as aldehydes and ketones. In particular, in aqueous polypropylene emulsions, metal components of salts added as, for example, surfactants, dispersants, and neutralizers may have a catalytic action during emulsification, and the oxidation deterioration of the unsaturated groups described above may occur. I believe it will promote In addition, even if the inorganic oxide particles contain a large amount of impurities, the same catalytic action may accelerate the oxidative deterioration of the unsaturated groups. It is preferable to reduce the impurity content so that the specific resistance at 20° C. is 1 kΩ·cm or more, particularly 40 kΩ·cm or more.

For example, the paint compounding agent of the present invention has a peak intensity ratio ((i)×(ii)/( ⁱⁱⁱ )/ (iv)) is 0.25 or less, preferably 0.20 or less. Details of peak intensities (i), (ii), (iii) and (iv) are shown below.
carbonyl group (>C═O, Wavenumbers 1701 cm ⁻¹ ) (i)
Carboxylate in carboxylate (—COO ⁻ , Wavenumbers 1558 cm ⁻¹ ) (ii)
Water (H ₂ O, Wavenumbers 1630 cm ⁻¹ ) (iii)
Polypropylene (PP, Wavenumbers 1461 cm ⁻¹ ) (iv)
A peak intensity ratio containing a carbonyl group (>C=O) was obtained from the following formula.
(i)×(ii)/(iii)/(iv)
In the above formula, the polypropylene chain is cut due to external factors such as heat history, and the part is oxidized to generate a carbonyl group, thereby increasing (i). A carboxylate is produced between carbonyl groups to increase (ii). On the other hand, (iii) decreases due to accelerated evaporation of water due to heat history, and (iv) decreases due to scission of polypropylene chains. As described above, the above formula is a parameter indicating the degree of oxidation of the inorganic oxide particles surface-treated with the aqueous emulsion of polypropylene wax.
These peaks calculated by FT-IR measurement are measured using Thermo Fisher Scientific FT-IR (Nicolet iS50), Harrick Scientific diffuse reflection attachment (Seagull), and detector DLaTGS. For example, when the incident angle is 15 degrees, the number of times of integration is 128, and the resolution is 4 cm ⁻¹ , the wavenumber can be observed (see FIG. 2). We believe that such a carbonyl group content indicates that the yellowing is due to oxidation of the polypropylene. That is, the inorganic oxide particles surface-treated with polyethylene wax are not oxidized as much as polypropylene during the surface treatment, so the carbonyl group content is smaller than that of the present invention. Moreover, even if polypropylene wax is used, the carbonyl group content thereof is smaller than that of the present invention even if it is melt-kneaded or surface-treated with an organic solvent.
As understood from this, in the present invention, the carbonyl group content within the above range means that the surface is treated with at least an aqueous polypropylene emulsion.

The surface-treated inorganic oxide particles used as the paint compounding agent of the present invention are surface-treated by an emulsion method so as to be as difficult to be oxidized as possible based on the cause of yellowing assumed by the present inventors. As a result, whether it is a small amount of surface treatment or a large amount of surface treatment, it has a high degree of whiteness as described above. This is a characteristic not found in oxide particles at all. For example, conventionally, such a high degree of whiteness has not been obtained even when small amounts are treated in laboratory experiments.

Additionally, the paint formulations of the present invention have a fairly low resistivity of less than 15 kΩ·cm at 20° C. measured in a 5% aqueous suspension. As described above, considering that the specific resistance of the inorganic oxide particles to be surface-treated is 40 kΩ cm or more, it is understood that the specific resistance is greatly reduced by this surface treatment. . That is, the paint compounding agent of the present invention is obtained by surface-treating the inorganic oxide particles by the emulsion method as described above. Various salts are transferred to the surface of the inorganic oxide particles together with the wax, and the polypropylene wax itself also has a polar group introduced by copolymerization. Therefore, the surface-treated inorganic oxide particles of the present invention have higher electrical conductivity than untreated inorganic oxide particles, and the specific resistance value is lowered as described above.

<Surface treatment>
As described above, the paint compounding agent of the present invention is obtained by surface treatment using an aqueous emulsion of high melting point polypropylene wax. Thus, the surface treatment by the emulsion method is performed under very strict control.

First, to explain roughly, the inorganic oxide particles described above are adjusted to an appropriate particle size (usually an average particle size of 1 to 50 μm) by pulverization or the like so as to be easily surface-treated, and dried to remove moisture. After removal, surface treatment is performed using an aqueous emulsion of the polypropylene wax described above by spraying the emulsion onto the sized inorganic oxide particles, followed by drying.

The polypropylene wax emulsion is sprayed onto the inorganic oxide particles by, for example, introducing the inorganic oxide particles into a mixer such as a Henschel mixer, spraying while stirring, and then drying.
The surface treatment can also be carried out by mixing and stirring the above-mentioned wax emulsion into a filtered and water-washed silica cake obtained by a gel method or a sedimentation method. In this case, the silica and the wax emulsion are mixed. Not only is it unavoidable to increase the number of large-scale stirring equipment and processing steps, but drying must be performed at a higher temperature than necessary for a long time. Surface-treated particles with whiteness cannot be obtained. Therefore, in order to obtain the surface-treated particles of the present invention, it is preferable to carry out the surface treatment by spraying as described above. For example, the inorganic oxide particles dried to a level of 10% by mass or less in water content are optimally subjected to surface treatment by spraying.

Further, when spraying as described above, depending on the amount of inorganic oxide particles charged into the mixer, the concentration of polypropylene wax in the emulsion to be sprayed, the spraying time, the temperature in the mixer during spraying, and the temperature after spraying Conditions such as drying temperature and drying time are set so as to obtain the aforementioned Hunter whiteness or carbonyl group content. That is, various conditions are set so as to suppress contact of the polypropylene wax with oxygen at high temperatures as much as possible within a range in which an appropriate surface treatment efficiency is ensured.

For example, the higher the solid content concentration (wax concentration) of the emulsion wax, the more the contact between the wax and oxygen is suppressed. On the one hand, the wax tends to solidify by itself, and it is difficult to perform a uniform surface treatment. In this case, it is possible to dilute the wax with water to reduce the concentration of the wax, thereby suppressing the solidification of the wax alone and performing a uniform surface treatment. should be avoided.
In addition, if the temperature in the mixer during spraying (spray spray temperature) and the subsequent drying temperature (temperature in the mixer after spraying) are too low, drying will take a long time, resulting in the desired Hunter whiteness. It becomes difficult to obtain surface-treated particles having On the other hand, if the temperature is too high, the oxidation of the wax will be accelerated, again making it difficult to obtain surface-treated particles with a high Hunter whiteness.
The shorter the spraying time, the better the treatment efficiency. must be set.
Furthermore, it is also necessary to set the drying time within an appropriate range. If this time is shortened, even if the treatment efficiency is improved, it is necessary to raise the drying temperature, and the increase in drying temperature promotes oxidation and causes a decrease in Hunter's whiteness (i.e., yellowing). It is from.

In this way, in order to prevent yellowing, the various conditions described above are related to each other. It is necessary to set and strictly control each condition.
By the way, suitable conditions for obtaining the surface-treated inorganic oxide particles of the present invention impregnated with a predetermined amount of polypropylene wax by putting 60 to 100 kg of inorganic particles into a Henschel mixer are as follows. is confirmed experimentally.
Emulsion concentration (wax concentration): 15 to 20% by mass
Spray atomization temperature (spray room temperature): 130-140°C
Spray time: 60-120 minutes Drying temperature: 130-140°C
Drying time: 0 to 30 minutes Although the drying itself begins at the same time as the spraying, the above drying time is the time after the end of the spraying.
A commercially available polypropylene wax emulsion can generally be used, and the concentration of the emulsion is adjusted by, for example, dilution with water.

In addition, in the present invention, the surface treatment and drying are performed in an inert gas atmosphere such as nitrogen without performing the detailed control of the conditions as described above, so that the desired yellowing does not occur and the surface has a high Hunter white color. Treated particles can be obtained. However, such means requires a surface treatment apparatus with a special structure, which is disadvantageous in terms of cost. Therefore, in the present invention, it is preferable to obtain the desired surface-treated inorganic oxide particles by controlling each condition in the surface treatment under normal atmosphere.

The surface-treated oxide particles of the present invention obtained by spraying and drying as described above are usually blended in media such as resins and paints for use. In addition, from the viewpoint of suppressing the viscosity increase of these media and ensuring workability, the average particle diameter (volume-based median diameter measured by the laser diffraction scattering method) is 1 to 50 μm, particularly 3 to 20 μm. It is pulverized and classified for use.
Furthermore, from the viewpoint of suppressing foaming due to moisture during heating when blended in the above medium, it is preferable to use after drying to a moisture content of 9% or less, particularly 5% or less.

<Application>
The paint compounding agent of the present invention can impart matte properties and low-slip properties to paint films by incorporating it into paints.
As paints, depending on the type of resin, conventional oil paints, nitrocellulose paints, alkyd resin paints, aminoalkyd paints, vinyl resin paints, acrylic resin paints, epoxy resin paints, polyester resin paints, chlorinated rubber paints, etc. In addition to paints known per se, rosin, ester gum, penta resin, coumarone-indene resin, phenolic resin, modified phenolic resin, maleic resin, alkyd resin, amino resin, vinyl resin, petroleum resin, epoxy resin, polyester resin, styrene resin, acrylic resin, silicone resin, rubber-based resin, chloride resin, urethane resin, polyamide resin, polyimide resin, fluorine resin, natural or synthetic lacquer and paints containing one or more of the above.

Also, the paints used are classified into solvent-based paints, water-based paints, curable paints, powder paints, etc., depending on how they are used. Since the surface is treated with a high-melting point polypropylene wax with a temperature of ℃ or higher, it is most suitable as a compounding agent for curable paints.
That is, curable paints contain, for example, thermosetting or UV-curable acrylic resins, epoxy resins, vinyl urethane resins, acrylic urethane resins, polyester resins, etc. as resin components, and are cured by heat or light irradiation (UV). It cures to form a coating film, and in oxide particles surface-treated with wax, the wax melts due to the heat generated during curing and bleeds to the surface, resulting in increased lubricity of the coating film. Otherwise, the matting property may be impaired. However, in the surface-treated oxide particles of the present invention, since the wax has a high melting point, bleeding due to temperature rise during curing is effectively suppressed, and the above problems do not occur.

Of course, the surface-treated oxide particles of the present invention can be used, for example, as an antiblocking agent with various thermoplastic resins, such as olefin resins, polyamides such as nylon 6, nylon 6-6, nylon 6-10, nylon 11 and nylon 12. , thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, polysulfones, vinyl chloride resins, vinylidene chloride resins, vinyl fluoride resins, and the like. In particular, in terms of their dispersibility, olefinic resins such as low-, medium- or high-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, or their copolymers with ethylene or α-olefins. certain polypropylene polymers, linear low-density polyethylene, ethylene-propylene copolymers, polybutene-1, ethylene-butene-1 copolymers, propylene-butene-1 copolymers, ethylene-propylene-butene-1 copolymers Polymers, ethylene-vinyl acetate copolymers, ionically crosslinked olefin copolymers (ionomers), ethylene-acrylic acid ester copolymers, blends thereof, etc. are particularly preferably blended, and polypropylene or its copolymer. Optimally blended into coalesce.

Furthermore, the surface-treated oxide particles of the present invention can be blended as a so-called filler into the thermoplastic resins, various rubbers, thermosetting resins, photo-setting resins, paper, and fibers.

The invention is illustrated by the following experimental examples. The physical properties and evaluation methods of various particles used in the present invention are as follows.

(1) Average Particle Size The volume-based median size was measured by a laser diffraction scattering method using Mastersizer 3000 manufactured by Malvern.

(2) Bulk Density Bulk density was measured by the iron cylinder method in accordance with JIS K 6220-1 7.8.2:2015.

(3) Moisture content The moisture content was calculated from the moisture content of the sample dried at 110°C.

(4) Specific resistance (20°C) when measured with a 5% aqueous suspension
A 5% aqueous suspension of the sample was prepared according to JIS K 5101-17-1:2004. The specific resistance of this suspension at 20° C. was measured with an electrical conductivity meter (DS-8F, manufactured by Horiba, Ltd.).

(5) Polypropylene wax content (wax adhesion amount)
The amount of polypropylene wax per 100 parts by mass of the inorganic oxide particles was measured by ignition loss at 1050°C.

(6) Hunter Whiteness Measured using a colorimeter ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.

(7) Peak intensity ratio including carbonyl group (>C=O) calculated by FT-IR measurement FT-IR (Nicolet iS50) manufactured by Thermo Fisher Scientific, diffuse reflection attachment (Seagull) manufactured by Harrick Scientific, and Using a detector DLaTGS, the following wavenumber peak intensity was measured at an incident angle of 15 degrees, 128 integration times, and a resolution of 4 cm ⁻¹ .
carbonyl group (>C═O, Wavenumbers 1701 cm ⁻¹ ) (i)
Carboxylate in carboxylate (-COO- ^, Wavenumbers 155
8 cm ⁻¹ ) (ii)
Water (H ₂ O, Wavenumbers 1630 cm ⁻¹ ) (iii)
Polypropylene (PP, Wavenumbers 1461 cm ⁻¹ ) (iv)
A peak intensity ratio containing a carbonyl group (>C=O) was obtained from the following formula.
(i)×(ii)/(iii)/(iv)

<Examples 1 to 7 and Comparative Examples 1 and 2>
Inorganic oxide particles used in this experimental example are shown.
(A) Silica: Mizusawa Chemical Industry Co., Ltd. gel method silica Mizukasil P-757C
(B) Aluminosilicate: sodium calcium aluminosilicate Shilton JC-30 manufactured by Mizusawa Chemical Industry Co., Ltd.
"Mizukasil" and "Silton" are registered trademarks of Mizusawa Chemical Industry Co., Ltd.
Table 1 shows physical properties of the inorganic oxide particles (A) and (B).

The surface treatment in this experimental example was performed using device (a) Henschel mixer (manufactured by Nippon Coke Kogyo Co., Ltd.) or device (b) super mixer (manufactured by Kawada Seisakusho), and the coating compounding agent was prepared according to the surface treatment conditions shown in Table 2. got
1 shows an aqueous emulsion of polypropylene wax (surface treatment agent) used in this experimental example.
(C) BYK polypropylene wax aqueous emulsion AQUACER 59
3 (melting point 160°C)
(D) Polypropylene wax aqueous emulsion P-9018 (melting point 156 ° C.) manufactured by Toho Chemical Co., Ltd.
(E) Aqueous emulsion of polypropylene wax manufactured by Maruyoshi Chemical Co., Ltd. MGP-1650
(Melting point 140°C)

The above inorganic oxide particles (A) or (B) and the aqueous emulsions (C) to (E) were blended as shown in Table 2 and subjected to surface treatment to obtain a paint formulation (Example 1 7 and Comparative Example 1).
Further, in Comparative Example 2, except for using a filter cake (water content of 64%) after dispersing the inorganic oxide particles (A) in water and a surface treatment agent (C) (wax concentration of 30%), -60231 was processed under the same conditions as in Example 6 to obtain a paint compounding agent.

Table 3 shows the physical properties of the paint formulations prepared in Examples 1 to 7 and Comparative Examples 1 and 2 above. FIG. 1 shows the relationship between the whiteness of these paint compounding agents and the peak intensity ratio including a carbonyl group (>C═O) calculated by FT-IR measurement.

<Paint test>
The paint is Kyoeisha Chemical Co., Ltd. urethane acrylate UA-306T, light acrylate 1.9ND-A, and 90 parts by mass of paint blended with P-200A, Kyoeisha Chemical Co., Ltd. Floren DOPA-100, and BASF An ultraviolet (UV) curable paint containing 5 parts by mass of IRGACURE 1173 manufactured by Japan Co., Ltd. was used. The inorganic oxide particles were blended in such a manner that 10 parts by mass of the inorganic oxide particles were blended with 100 parts by mass of the UV curable paint. The dispersing conditions were T.I. K. A HOMODISPER (Model 2.5) was used and the number of revolutions was 1500 rpm for 5 minutes. Coating conditions were BYK-Gardner Cat. No. Using a 2120 applicator, it was applied to a standard test plate (glass) manufactured by Nippon Test Panel Co., Ltd. As for the curing conditions, a UV conveyor device (Eye Mini Grandage ECS-1511U) manufactured by Eye Graphics Co., Ltd. was used, and the integrated light amount was 115 to 130 mJ/cm ² .
Viscosity was measured using VISCOMETER TVB-10 (CORD No. 21) manufactured by Toki Sangyo Co., Ltd. at rotation speeds of 6, 30 and 60 rpm (40°C). Viscosity is shown in FIG. The 60° gloss was measured using a Gloss Meter VG2000 manufactured by Nippon Denshoku Industries Co., Ltd. The film thickness was measured using THICKNESS METER B1 manufactured by Toyo Seiki Seisakusho Co., Ltd. Table 4 shows the 60° gloss and film thickness.

Claims (6)

A paint compounding agent comprising inorganic oxide particles surface-treated with an aqueous emulsion of polypropylene wax having a melting point of 140° C. or higher,
The polypropylene wax is contained in an amount of 1 to 15 parts by mass per 100 parts by mass of the inorganic oxide particles,
A compounding agent for paint, characterized by having a Hunter whiteness of 90% or more. 2. The coating formulation according to claim 1, wherein said inorganic oxide particles have a bulk density of 0.1 to 1.5 g/cm ³ . 3. The paint compounding agent according to claim 1, wherein said inorganic oxide particles are silica. Carbonyl group calculated by FT-IR measurement (>C═O, Wavenumbers 1701 cm ⁻¹ ) (i), carboxylate in carboxylate (—COO ⁻ , Wavenumbers 1558 cm ⁻¹ ) (ii) ), water (H ₂ O, Wavenumbers 1630 cm ⁻¹ ) (iii), polypropylene (PP, Wavenumbers 1461 cm ⁻¹ ) (iv) Peak intensity ratio ((i) × (ii) / ( The paint compounding agent according to any one of claims 1 to 3, wherein iii)/(iv)) is 0.25 or less. The paint compounding agent according to any one of claims 1 to 4, wherein the average particle size is adjusted to 1 to 50 µm. The paint compounding agent according to any one of claims 1 to 5, which is used as a curable paint compounding agent.

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